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terça-feira, 27 de janeiro de 2015

Perovskites provide big boost in silicon solar cells

 

 

Thu, 01/22/2015 - 1:04pm

Mark Shwartz, Stanford Univ.

Stacking perovskites, a crystalline material, onto a conventional silicon solar cell dramatically improves the overall efficiency of the cell, according to a new study led by Stanford Univ. scientists.

The researchers describe their novel perovskite-silicon solar cell in Energy & Environmental Science.

"We've been looking for ways to make solar panels that are more efficient and lower cost," said study co-author Michael McGehee, a professor of materials science and engineering at Stanford. "Right now, silicon solar cells dominate the world market, but the power conversion efficiency of silicon photovoltaics has been stuck at 25% for 15 years."

One cost-effective way to improve efficiency is to build a tandem device made of silicon and another inexpensive photovoltaic material, he said.

"Making low-cost tandems is very desirable," McGehee said. "You simply put one solar cell on top of the other, and you get more efficiency than either could do by itself. From a commercial standpoint, it makes a lot of sense to use silicon for the bottom cell. Until recently, we didn't have a good material for the top cell, then perovskites came along."

Perovskite is a crystalline material that is inexpensive and easy to produce in the lab. In 2009, scientists showed that perovskites made of lead, iodide and methylammonium could convert sunlight into electricity with an efficiency of 3.8%. Since then, researchers have achieved perovskite efficiencies above 20%, rivaling commercially available silicon solar cells and spawning widespread interest among silicon manufacturers.

"Our goal is to leverage the silicon factories that already exist around the world," said Stanford graduate student Colin Bailie, co-lead author of the study. "With tandem solar cells, you don't need a billion-dollar capital expenditure to build a new factory. Instead, you can start with a silicon module and add a layer of perovskite at relatively low cost."

Sunlight to electricitySolar cells work by converting photons of sunlight into an electric current that moves between two electrodes. Silicon solar cells generate electricity by absorbing photons of visible and infrared light, while perovskite cells harvest only the visible part of the solar spectrum where the photons have more energy.

"Absorbing the high-energy part of the spectrum allows perovskite solar cells to generate more power per photon of visible light than silicon cells," Bailie said.

A key roadblock to building an efficient perovskite-silicon tandem has been a lack of transparency.

"Colin had to figure out how to put a transparent electrode on the top so that some photons could penetrate the perovskite layer and be absorbed by the silicon at the bottom," McGehee said. "No one had ever made a perovskite solar cell with two transparent electrodes."

Perovskites are easily damaged by heat and readily dissolve in water. This inherent instability ruled out virtually all of the conventional techniques for applying electrodes onto the perovskite solar cell, so Bailie did it manually.

"We used a sheet of plastic with silver nanowires on it," he said. "Then we built a tool that uses pressure to transfer the nanowires onto the perovskite cell, kind of like a temporary tattoo. You just need to rub it to transfer the film."

Remarkable efficiencyFor the experiment, the Stanford team stacked a perovskite solar cell with an efficiency of 12.7% on top of a low-quality silicon cell with an efficiency of just 11.4%.

"By combining two cells with approximately the same efficiency, you can get a very large efficiency boost," Bailie said.

The results were impressive.

"We improved the 11.4% silicon cell to 17% as a tandem, a remarkable relative efficiency increase of nearly 50%," McGehee said. "Such a drastic improvement in efficiency has the potential to redefine the commercial viability of low-quality silicon."

In another experiment, the research team replaced the silicon solar cell with a cell made of copper indium gallium diselenide (CIGS). The researchers stacked a 12.7% efficiency perovskite cell onto a CIGS cell with a 17% efficiency. The resulting tandem achieved an overall conversion efficiency of 18.6%.

"Since most, if not all, of the layers in a perovskite cell can be deposited from solution, it might be possible to upgrade conventional solar cells into higher-performing tandems with little increase in cost," the authors wrote.

A big unanswered question is the long-term stability of perovskites, McGehee added.

"Silicon is a rock," he said. "You can heat it to about 600 degrees Fahrenheit, shine light on it for 25 years, and nothing will happen. But if you expose perovskite to water or light, it likely will degrade. We have a ways to go to show that perovskite solar cells are stable enough to last 25 years. My vision is that some day we'll be able to get low-cost tandems that are 25% efficient. That's what companies are excited about. In five to 10 years, we could even reach 30% efficiency."

Source: Stanford Univ.

domingo, 25 de janeiro de 2015

Máquinas para trabalhar em casa

 

                                                               Trabalhe em casa e ganhe dinheiro

New nicotine vaccine may succeed at treating smoking addiction, where others have failed

 

 

A vaccine currently in development may be more effective at keeping nicotine molecules fro...

A vaccine currently in development may be more effective at keeping nicotine molecules from acting on the brain (Photo: Shutterstock)

If you're a smoker who's trying to quit, you may recall hearing about vaccines designed to cause the body's immune system to treat nicotine like a foreign invader, producing antibodies that trap and remove it before it's able to reach receptors in the brain. It's a fascinating idea, but according to scientists at California's Scripps Research Institute, a recent high-profile attempt had a major flaw. They claim to have overcome that problem, and are now developing a vaccine of their own that they believe should be more effective.

There are actually two forms of nicotine, and they're like molecular mirror images of one another. These are known as the left-handed and right-handed versions. Although about 99 percent of the nicotine found in tobacco is the left-handed version, a previous vaccine created by a biopharmaceutical company caused the body to create antibodies against both types.

According to lead scientist Prof. Kim Janda, this was a partial waste of the immune response, causing the vaccine to not be as effective as it could have been. As a result, it only worked on 30 percent of test subjects in clinical trials.

Instead, his team has created a vaccine which causes the body to only produce antibodies that target left-handed nicotine molecules – none of the immune response goes towards making antibodies that won't be needed. In lab tests on rats, the vaccine was found to be 60 percent more effective at producing left-handed-nicotine-targeting antibodies than an alternate version, which was made from a 50-50 mix of both left- and right-handed nicotine derivatives known as haptens.

The scientists are now trying to establish how consistently such a vaccine would work across large populations of users, given the variations in individuals' immune systems. They also note that even if it does work to remove the physiological reward system for smoking, users would still have to deal with smoking-withdrawal symptoms.

A paper on the research was recently published in the Journal of Medicinal Chemistry. Another nicotine vaccine, utilizing some of Janda's materials, is currently being developed at Weill Cornell Medical College.

Sources: Scripps Research Institute, American Chemical Society

 

When Scientists Choose Motherhood

 

 

A single factor goes a long way in explaining the dearth of women in math-intensive fields. How can we address it?

Wendy M. Williams, Stephen J. Ceci

I have frequently been questioned, especially by women, of how I could reconcile family life with a scientific career. Well, it has not been easy.
—Marie Curie, two-time Nobel Prize winner and mother of a daughter, Irène Joliot-Curie, who also won the Nobel Prize

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Jennifer was an extremely talented undergraduate, majoring in mathematics and engineering. Her grades and test scores were nearly perfect; her professors saw a bright future for her as an engineering professor and encouraged her to pursue a doctorate. In graduate school, she continued to excel, accumulating high-quality publications, fellowships and awards. She landed a premier postdoctoral position and was headed for a first-tier professorship. But she never applied for a tenure-track academic job. As a 33-year-old postdoc, she could not imagine waiting to have children until after tenure at age 40, nor could she imagine how she would juggle caring for a young family with the omnipresent demands of an assistant professorship. The harried lives of the two tenured mothers in her department convinced her that such a path was not for her. Jennifer made the choice to have a family and teach mathematics part-time at a local community college.

Although it’s not hard to find evidence of women professors’ many successes in the academy, scenarios like Jennifer’s are all too common. Women hold a substantial portion of professorships in the humanities and liberal arts, and they are well represented in the social sciences and some fields of natural science, such as biology. Overall, women make up 33 percent of faculty at doctoral-level institutions. They receive many teaching and service awards and do as well as men in winning grants. But women are in short supply in math-intensive fields, such as chemistry, physics, mathematics, engineering and computer science. For example, in the top 100 U.S. universities in 2007, women full professors in these fields numbered only 4.4 to 12.3 percent, and women were only 16 to 27 percent of assistant professors (see Figure 2).

2012-03WilliamsF2.jpgWhat is going on here? Why are women who are talented and dedicated enough to graduate from college with degrees in mathematics not progressing through graduate school and ultimately earning full professorships? Where are these women going, and why do they leave their chosen field?

Much has been written about the underrepresentation of women professors in math-intensive fields, particularly in upper-level positions. Despite the substantial amount of high-quality data on this issue, however, myths and misunderstandings prevail. Potentially addressable issues that limit women are often ignored, and efforts and resources are misdirected toward solving problems that no longer exist.

The usual explanations for the shortage of women focus squarely on sex discrimination at various life stages. As a result of such discrimination, the argument goes, girls and women drop out of math-based endeavors or change their focus. Some scholars have argued for the effects of early socialization practices that lead girls along a path that downplays math—pink versus blue attire for babies, Barbie dolls proclaiming “Math class is tough,” middle-school math teachers calling on boys more than girls, high-school girls urged to be cheerleaders or writers instead of scientists. Others invoke gender stereotypes—sets of shared cultural expectations that suggest, for instance, that females are not gifted in math or that the responsibility for raising children belongs primarily or solely to women. Still others look further down the pipeline, at disenfranchisement of women once they enter academic-science careers, focusing on claims of “chilly climate”; unequal pay and promotion; devaluing of women’s work styles and biased assessment of their efforts; and old-boys’ clubs that isolate women. Researchers have also studied the role of sex differences at the extreme right tail of the math distribution—more boys than girls demonstrate extremely high levels of math ability on standardized tests such as the SAT. Still others suggest that women simply prefer to use their math and science skills to be veterinarians and biologists, for example, rather than engineers and computer scientists, and that the difference in the numbers can be explained by this freely determined preference.

We argue for the importance of another factor in women’s underrepresentation: the choice to become a mother. To place the role of this choice in context, we consider its impact on women’s careers relative to the impacts of other variables that may reduce women’s participation in the sciences. Our own findings as well as research by others show that the effect of children on women’s academic careers is so remarkable that it eclipses other factors in contributing to women’s underrepresentation in academic science.

Unlikely Causes

Three major sets of factors have been offered to explain the dearth of women in math-intensive fields: ability differences; occupational and lifestyle preferences; and sex discrimination. Elsewhere we have extensively reviewed the evidence for several of these issues; here we provide a summary.

2012-03WilliamsF3.jpgAbility differences: Scholars once thought sex differences that favored men on tests of quantitative ability were responsible for the shortage of women in math-based fields. Although there are no systematic sex differences in average scores on tests such as the SAT mathematics (SAT-M), many more men score in the very top range. For example, among the top 0.01 percent (1 in 10,000) of scorers in nonrandom samples, there are about 4 men for every woman. College admissions committees may admit more men because of their higher SAT-M scores, setting in motion a cycle of women’s attrition.

Yet this cannot be the whole story or even a large part of it. Starting about two decades ago, women began gaining on men in math ability and participation. By 2005, men and women were almost equally represented among college math majors, and women tend to get better grades in math courses. But far fewer women than men enroll in math-based Ph.D. programs. The GRE-Quantitative scores of graduate students in math-intensive fields at our own university are very high across the board. These students come from the top end of the ability distribution, and the test actually underestimates their ability due to ceiling problems (there are not enough very hard questions to distinguish the truly exceptional from the merely talented). So, since fewer women score in the top range on tests used for admission to Ph.D. programs, this fact may be responsible for some of the shortage of women in math-intensive careers.

As compelling as this argument seems, however, there are several problems with it. Females outperform males in math classes throughout schooling, including in college. Surely graduate-admissions decision makers take women’s higher GPAs into account. Also, even if among the top 1 percent of scorers there were 2 males for every female, there should still be more women in math-based disciplines, because we do not see anything close to a 2-to-1 ratio of men to women in these careers. Recall that 12 percent or less of full professors in these fields are women. Something more than scoring at the right tail is responsible.

Some researchers argue that those who succeed in mathematical fields come from more rarefied strata than the top 1 percent. David Lubinski, Camilla Benbow and their associates at Vanderbilt University have shown that those in the topquarter of the top 1 percent of scorers outperform those in the bottomquarter of the top 1 percent in obtaining tenure-track jobs, publishing articles and patents, and other indicators of excellence and success. If extremely high math ability is important to success, and if many more men possess this extreme ability than do women, perhaps it is responsible for observed ratios of men to women in math-based fields. Although further investigation might show a correlation between success and scores in the far-right tail of the range, no one has demonstrated a causal relation between the two factors. We do know that math-talented women are less likely than equivalently math-talented men to enter mathematical professions. In other words, many fewer women than men choose mathematical fields—even when they have comparable math scores.

There is no direct evidence that men’s math-score advantage explains this shortage of women. Forty-five percent of undergraduate degrees in mathematics go to women, as do 29 percent of Ph.D.s, suggesting that whatever these women’s math skills, they are compatible with very high levels of achievement. Thus, we believe mathematical differences between the sexes are not primary factors in women’s underrepresentation in math-heavy fields.

Career preferences and lifestyle differences: If cognitive differences cannot explain most of the shortage of women in these careers, what about sex differences in career preferences and lifestyle choices? Surveys have documented that females, starting at a young age, are more interested in careers that involve living things—such as medicine, biology, animal science and psychology—than fields such as computer science, mathematics, physics and engineering. Adolescent girls seldom name engineering and computer science as desired careers, whereas nearly a quarter of adolescent boys do. Unlike some researchers, we are not overly worried by these findings, because careers in biology, medicine and veterinary science seem as valuable and satisfying as those in math-based fields. It would be troubling if adolescents declined to try such professions on the basis of faulty information about what is possible, but as long as they are doing so to pursue careers they perceive as more rewarding, society still benefits from these young people’s talents.

A related factor concerns life-course differences between the sexes. In surveys of graduate students, Lubinski, Benbow and their students found that female graduate students viewed a full-time career as “important” or “extremely important” about as often as did their male counterparts (77 percent versus 81 percent, respectively). However, when it came to the importance of temporarily having a part-time career, significant sex differences emerged (31 percent versus 9 percent, respectively), as well as for always having a part-time career (19 percent versus 9 percent, respectively).

Such life-course preferences can lead to differences in research productivity and hours spent at the office, reflecting differing priorities in optimal life-work balance. Lubinski studied the amount of time that nearly 2,000 33-year-olds, who were in the top 1 percent of quantitative ability during their adolescence, spent on career-related work. He found that roughly twice as many high-aptitude men as women reported working at their jobs more than 50 hours per week. Other surveys underscore this male advantage in working very long hours.

Sex discrimination in publishing, funding and hiring: A frequent claim is that women are derailed by sex discrimination in publishing their work, obtaining grant funding and being hired. However, although these forms of discrimination may have played important roles historically, none of these causes can explain today’s underrepresentation. In an article in the Proceedings of the National Academy of Sciences of the U.S.A., we reviewed the evidence and concluded that such discrimination is not responsible for the current dearth of women. Consider one example of the research we synthesized. In 2004 and 2005, a National Research Council committee surveyed U.S. university departments and faculty in a number of math-intensive fields about their interviewing, hiring and promotion records. It found that women applicants were actually more likely to be interviewed and offered tenure-track jobs than were their male competitors, and that there were no differences in tenure and promotion rates for women and men. A number of other analyses have reached the same conclusions. In mathematics, only 20 percent of applicants for tenure-track posts were women, but 28 percent of those invited to interview were women, as were 32 percent of those offered positions.

2012-03WilliamsF4.jpg

The picture is much the same for funding and publishing. Women scientists are as successful as men at publishing work and at earning grant funding, according to analyses of hundreds of thousands of grant applications submitted throughout the United States, Canada, the United Kingdom and Australia.

Thus, the shortage of women in mathematical fields is not the result of discriminatory hiring, publishing and funding, nor can it be explained away on the basis of ability differences. Some portion of the dearth of women in math fields can clearly be traced to differences between the sexes in career preferences. Women’s greater desire for lifestyle flexibility, reflecting differing ideas about work-life balance and different expectations regarding responsibility for raising children and working in the home, also plays a role. This latter point leads to what we see as the single most important factor in explaining women’s underrepresentation: a desire for children and family life.

The Perils of Motherhood

It is when academic scientists choose to be mothers that their real problems start. Women deal with all the other challenges of being academic scientists as well as men do. Childless women are paid, promoted and rewarded equivalently to their male peers (and in some analyses at even higher rates). Children completely change the landscape for women—but do not appear to have the same effect on the careers of men. What happens when children enter the equation, and why does this change seem to impact women’s but not men’s careers?

2012-03WilliamsF5.jpgAnswering this question requires knowledge about the typical course of an academic career. Most college students interested in becoming professors in the sciences graduate from college and matriculate in graduate school soon thereafter. Earning a doctorate takes five to six years on average; it is common to work as a postdoctoral associate for several years after the doctorate. By the time students contemplate applying for tenure-track academic jobs, they are at least 27 years old, and on average 33. Landing a job means applying broadly and being willing to relocate, giving the search priority over the needs of partners or spouses. The next six years are spent in relentless efforts to accumulate an impressive portfolio of work—encompassing research, teaching, service and grants—until finally, at age 35 or older, a professor may be fortunate enough to earn tenure. Research by Jerry Jacobs and Sarah Winslow has shown that more than 60 percent of female untenured professors are over 40, and Mary Ann Mason and Mark Goulden showed the average age of tenure was already 39-plus by 2003.

Women’s optimal fertility is between ages 18 and 31. By age 37, many will have difficulty conceiving. Waiting to have children has not only physical aspects but also emotional ones—some women want to have children when they are younger. For women, the tenure track presents a harsh reality that juxtaposes the most significant physical and emotional challenges of their lives with the most significant professional challenges. It’s easy to see why the pretenure years might be off-putting for a woman who does not wish to delay having children until her late thirties—she must deal with pregnancy, childbirth and child care while simultaneously amassing a tenurable portfolio of work. This reality is too daunting for some women, and they either leave the tenure-track pipeline or give up on having children.

Surveys have shown that regrets plague women in the academy at a far greater rate than they do men. In a 2002–2003 survey of around 4,500 University of California faculty members by Mason, Angelica Stacy, and Goulden, 38 percent of women but only 18 percent of men stated that they “regret not having children” or “regret not having more children.” In research by Elaine Ecklund and Anne Lincoln at Rice University and Southern Methodist University, nearly 40 percent of women graduate students said they had fewer children than they wanted because of the pressure of their careers (versus only 20 percent of men), as did 45 percent of women faculty in astronomy, biology and physics (versus only 25 percent of men). Often this regret is associated with leaving the academy.

2012-03WilliamsF6.jpgMen more often have stay-at-home spouses or spouses in flexible careers who bear and raise children while the men are free to focus on academic work. Women professors in heterosexual partnerships who want to bear children, by virtue of biology, can never achieve this same distance from childrearing, and male stay-at-home partners devoted to child care are rare. Mason and her colleagues found that mothers are 35 percent less likely to enter the tenure track and 38 percent less likely to achieve tenure than fathers, and twice as likely as fathers to work in part-time or non–tenure-track positions. Only one in three women who accepts a fast-track university job before having a child ever becomes a mother. Among tenured scientists, only 50 percent of women are married with children, compared to 72 percent of men, and women married when beginning faculty careers are much more likely to divorce or separate than men. For women who want to have children and a career in science, the picture is not pretty.

If women’s fears about the effects of having children on their careers were unfounded, we could simply educate young women scientists about what really happens and relieve them of their anxiety. But in fact, children represent a dramatic influence on women’s life paths and work productivity. To complicate the situation further, in some cases children have a positive impact on men’s productivity. Research by David Leslie has shown that the more children a woman has, the fewer hours per week she spends on her professional work, while the exact opposite is true for men.

Both for men and for women who have no children or plans to have them, the process of becoming a tenured professor in a scientific field depends on single-minded pursuit of academic goals. Whether measured in hours spent or in percentage of one’s life energy devoted, the job demands devotion to the task at a level that is extraordinarily challenging for women who are mothers of young children. The tenure system was created at a time when few women worked outside the home and when raising children was assumed to be women’s work, and thus it was designed for people without significant responsibilities in household work or child care. In fact, many early professors were unmarried men who were expected to live in residence at their universities. A lot has changed since then, but the tenure system itself has remained much the same.

The research by Mason, Stacy and Goulden found that childless women and childless men professors report working an average of 78 hours per week across all life domains (in the workplace and at home), and men with children work 88 hours per week. But women with children work 100-plus hours per week across all life domains. Among assistant professors with children, women spend nearly 4 hours fewer per week on their professional careers than do men (52.5 versus 56.3), according to Jacobs and Winslow. The impact of children on women is especially dramatic for the proportion working 60-plus hours per week—42 percent of married male assistant professors with children work 60-plus hours per week, compared to only 29 percent of married women with children. The reality of the lives of women professors with children may seem too stark for their younger colleagues, postdocs and students.

2012-03WilliamsF7.jpgThe role of children in women’s versus men’s decisions about whether to stay in a research-intensive career track or opt out of it can also be seen in research by Goulden, Karie Frasch and Mason. They show that once children—or even plans for children—exist, women become far more likely to move out of the research-professor pipeline. Women with no plans for children show decision making comparable to men, exhibiting about the same likelihood of opting out of research-professor careers.

This single factor of having or wanting children has great impact. In some analyses, females are twice as likely as males to decide not to pursue tenure-track careers as a result of this factor. Having children prior to working as a postdoctoral associate creates a 19 percent likelihood for men of opting out, versus 32 percent for women; having new children after beginning postdoctoral work creates a 20 percent versus 41 percent difference. No other factor can account for as much leakage of women from the research-professor pipeline. The percentage of women in the applicant pool at each of several key transition points shows this decline: From award of Ph.D., to application for tenure-track positions, to being invited to interview, to being offered a tenure-track job, to being promoted to associate and full professor, women’s numbers diminish. The proportion of applications from women is significantly lower than the proportion of doctoral degrees awarded to women. This gap is more pronounced in some fields than in others; for example, the difference is quite substantial in chemistry and biology, two disciplines with relatively high proportions (32 percent and 46 percent, respectively) of recent Ph.D.s awarded to women. However, when women do apply for tenure-track positions, they are more likely to be interviewed and hired than their proportion in the applicant pool (as opposed to their proportion in the Ph.D. pool) would lead one to expect. These data, in sum, lead us to conclude that the dynamics of family formation in Western society—not biased hiring committees, journal reviewers and grant panelists—are the primary cause of the underrepresentation of women in academic science.

2012-03WilliamsF8.jpgDo women in nonacademic careers face the same challenges? At least in some fields, the answer is yes. The economists Marianne Bertrand, Claudia Goldin and Lawrence Katz surveyed nearly 2,500 University of Chicago M.B.A.s who graduated between 1990 and 2006. More women M.B.A.s dropped out of the full-time workforce with each added year following their degree. As their biological clocks ran down, significantly fewer remained in full-time and part-time employment. Although this situation is also seen among women in medicine and among Ph.D.s, it is exacerbated in business, particularly for those jobs associated with work weeks of more than 60 hours (investment banking, consulting) or close to 60 hours (venture capital, sales, trading). For the first few years following receipt of their M.B.A., men and women have similar labor-force participation, both at nearly 100 percent. However, 10 years after graduation, among women who have one or more children, only 52 percent work full-time and full year. Sex differences in labor-force participation widen as careers progress.

Women are not found in greater numbers in some fields, particularly math-intensive ones, due to a combination of factors. The two most significant reasons are that women are more likely than men to prefer other fields (such as medicine, biology, law and veterinary science, rather than mechanical and electrical engineering, computer science and physics), even when they have comparable mathematical ability, and that family-formation goals extinguish tenure-track aspirations in women more often than in men. The majority of child care, housework and household management is done by women, and women scientists are no exception in assuming this greater burden. Although this second factor affects women in all fields of science, not just math-intensive ones, the lower numbers of women entering graduate programs in math-based fields means that any factor that further reduces their number results in a dearth of tenure-track female faculty. At the top 100 universities in the 1996-to-2005 cohort, less than a third of Ph.D.s in math-intensive fields were women, and in three of those fields less than 15 percent of Ph.D.s were women. Fields such as biology, psychology, sociology and medicine, in which the majority of new Ph.D.s and M.D.s are now women, are able to retain a larger number of women in the tenure-track pipeline, even after family-driven attrition.

Policy Changes with Potential

2012-03WilliamsF9.jpgIf sex discrimination in interviewing and hiring, or in reviewing of women’s work products, were responsible for the dearth of women professors in math-intensive fields, we would advocate interventions targeting these issues. But current data show that our society has moved past these types of blatant discrimination. Of course, more subtle forms of discrimination may operate today, and we await empirical data supporting their existence and illuminating optimal pathways to address them.

One potentially promising way to increase women’s representation is to focus efforts on the problems faced by mothers struggling to raise young families while building tenurable scholarly records. Accordingly, we advocate evaluation of an assortment of strategies (suggested by ourselves and by others, such as Mason and her colleagues) to determine which have promise. For instance, universities might educate women graduate students about the downsides of alternative career paths, following partners’ career moves and taking time off. They could explore the use of part-time tenure-track positions for women having children that segue to full-time once children are older, and offer members of a couple the option to temporarily share a single full-time position. Further strategies include not penalizing older or nontraditional applicants for jobs; leveraging technology to enable parents to work from home while children are young or ill; providing parental leaves for primary caregivers of either gender and offering funding to foster successful reentry; and providing an academic role for women who have left professional positions to have children. Institutions could also try stopping tenure clocks for primary caregivers during family formation; adjusting the length of time allocated for work on grants to accommodate childrearing; offering no-cost grant extensions; providing supplements to hire postdocs to maintain labs during family leave; reducing teaching loads for parents of newborns; providing grants for retooling after parental leave; hiring couples; offering child care during professional meetings; providing high-quality university-based child care and emergency backup care; and instructing hiring committees to ignore family-related gaps in curricula vitae. Ensuring that adolescent girls and boys have access to accurate career information is also important, so that misinformation does not lead young people to opt out of careers they might have found rewarding. Some of these strategies have been implemented at some universities; a range of adjustments to the tenure process will be necessary to ensure that women and men who want to have children and be primary caregivers will have equal opportunity.

Key factors that limit women today are still in need of solutions. It is time for our society to address them. The stresses faced when raising young families drive women out of careers for which they are trained and in which they would be as successful as men were they to make the choice not to have children. This critical constraint, which has both biological and cultural aspects, creates a sometimes grim and seemingly unfair reality for women that men simply do not face. Modern universities must create policies to target this real issue, which is supported by extensive empirical data, and which lies at the heart of the current problem.

 

 

Prompt Use of Antivirals is Key this Flu Season

 

 

Doctor talking with mature man

Influenza activity in the United States is widespread and likely to continue for weeks. Read more about what physicians can do.

A report published in the January 16th edition of the Morbidity and Mortality Weekly Report (MMWR) estimates that this season’s flu vaccine reduced a person’s risk of going to the doctor because of flu by 23 percent for all ages.

The MMWR report states the reduced protection offered by flu vaccine this season underscores the need for additional prevention and treatment efforts, including the appropriate use of influenza antiviral medications for treatment. (Read more about the effectiveness of this year’s flu vaccine in the January 15th press release).

Antiviral influenza (flu) medications are effective in treating the flu and reducing complications, and are critical tools for reducing the burden of flu illness. Unfortunately, evidence from previous and the current flu season suggest that flu antiviral drugs are severely underused. One recent study by Havers et al, reported that only 19% of high-risk outpatients who would benefit the most from and who should have gotten treated with flu antivirals actually did.

Current Flu Vaccine Effectiveness

Since CDC began conducting annual flu vaccine effectiveness (VE) studies in 2004-2005, overall estimates for each season have ranged from 10 percent to 60 percent effectiveness in preventing medical visits associated with seasonal influenza illness.

One factor that determines how well a flu vaccine works is the similarity between the flu viruses used in vaccine production and the flu viruses actually circulating. During seasons when vaccine viruses and circulating influenza viruses are well matched, VE between 50 percent and 60 percent has been observed.

H3N2 viruses have been predominant so far this season, but about 70 percent of them have been different or have “drifted” from the H3N2 vaccine virus. This likely accounts for the reduced VE.

CDC has done limited qualitative research into clinician knowledge, attitudes and practices related to anti-influenza drugs. The findings suggest that there are probably a number of factors involved. These include:

  • low clinician awareness of CDC’s antiviral recommendations;
  • a wide range in perception about how well these drugs work;
  • some clinicians may require  a positive flu test before prescribing antivirals (even though the results of rapid influenza diagnostic tests, if ordered, may not be accurate);
  • and lastly, some physicians may not prescribe antivirals after the 2-day window during which benefit is optimal.

CDC is working to understand clinicians’ concerns and improve awareness of the benefits offered by antivirals.

Messages to Clinicians

CDC's antiviral recommendations are summarized in Influenza Antiviral Medications: Summary for Clinicians, and are also available in CDC Health Update Regarding Treatment of Patients with Influenza with Antiviral Medications (Distributed January 9, 2015).

Note the following important messages:

  1. Influenza activity is currently widespread, so influenza should be high on the list of possible diagnoses for ill patients.
  2. All hospitalized, severely ill and high risk patients with suspected influenza should be treated with antivirals.
  3. CDC recommends antiviral medications for treatment of influenza as an important adjunct to annual influenza vaccination. Treatment with antivirals has been shown to have clinical and public health benefit in reducing illness and severe outcomes of influenza, as evidenced from randomized controlled trials, meta-analyses of randomized controlled trials, and observational studies conducted during past influenza seasons and during the 2009 H1N1 pandemic.All hospitalized patients and all high-risk patients (either hospitalized or outpatient) with suspected influenza should be treated as soon as possible with one of three available influenza antiviral medications.
  4. Antiviral treatment should commence regardless of a patient’s vaccination status, and without waiting for influenza confirmatory testing.
  5. While antiviral drugs work best when given early, therapeutic benefit has been observed even when treatment is initiated later for some patients.

Mother taking son's temperature

Antiviral drugs work best for flu treatment when they are started within 2 days of getting sick. However, starting antivirals later can still be helpful for some people.

Resources for Patient Education

Results from unpublished CDC qualitative research shows that most people interviewed were not aware that drugs to treat influenza illness are available. Patients being provided a prescription for an influenza antiviral drug may have questions. A fact sheet for patients is available.

Note the following important background information for patients:

  • If you get the flu, antiviral drugs are a treatment option.
  • It is very important that antiviral drugs are used early to treat hospitalized patients, people with severe flu illness, and people who are at high risk for flu complications because of their age, severity of illness, or underlying medical conditions.
  • If you have severe illness or are at high risk of serious flu complications, you may be treated with flu antiviral drugs if you get the flu.
  • For people with a high-risk condition, treatment with an antiviral drug can mean the difference between having milder illness instead of very serious illness that could result in a hospital stay.
  • Other people also may be treated with antiviral drugs by their doctor this season. Most otherwise-healthy people who get the flu, however, do not need to be treated with antiviral drugs.
  • Studies show that flu antiviral drugs work best for treatment when they are started within 2 days of getting sick. However, starting antivirals later can still be helpful for some people.
  • If your health care provider thinks you have the flu, your health care provider may prescribe antiviral drugs. A test for flu is not necessary.
  • Antibiotics are not effective against the flu. Using antibiotics inappropriately can lead to antibiotic resistance and may expose patients to unwanted side effects of the drug.
  • Other practices that may help decrease the spread of influenza include respiratory hygiene, cough etiquette, social distancing (e.g., staying home from work and school when ill, staying away from people who are sick) and hand washing.

sábado, 24 de janeiro de 2015

How to be happy: Tips for cultivating contentment

 

Are you tired of waiting around for happiness to find you? Stop waiting and start getting happy with these tips. By Mayo Clinic Staff

Do you know how to be happy? Or are you waiting for happiness to find you?

Despite what the fairy tales depict, happiness doesn't appear by magic. It's not even something that happens to you. It's something you can cultivate.

So, what are you waiting for? Start discovering how to be happy.

How to be happy: What science tells us

Only 10 percent or so of the variation in people's reports of happiness can be explained by differences in their circumstances. It appears that the bulk of what determines happiness is due to personality and — more importantly — thoughts and behaviors that can be changed.

So, yes, you can learn how to be happy — or at least happier.

Although you may have thought, as many people do, that happiness comes from being born rich or beautiful or living a stress-free life, the reality is that people who have wealth, beauty or less stress are not happier on average than those of who don't enjoy those blessings.

People who are happy seem to intuitively know that their happiness is the sum of their life choices, and their lives are built on the following pillars:

  • Devoting time to family and friends
  • Appreciating what they have
  • Maintaining an optimistic outlook
  • Feeling a sense of purpose
  • Living in the moment
How to be happy: Practice, practice, practice

If you have been looking for happiness, the good news is that your choices, thoughts and actions can influence your level of happiness. It's not as easy as flipping a switch, but you can turn up your happiness level. Here's how to get started on the path to creating a happier you.

Invest in relationships

Surround yourself with happy people. Being around people who are content buoys your own mood. And by being happy yourself, you give something back to those around you.

Friends and family help you celebrate life's successes and support you in difficult times. Although it's easy to take friends and family for granted, these relationships need nurturing.

Build up your emotional account with kind words and actions. Be careful and gracious with critique. Let people know that you appreciate what they do for you or even just that you're glad they're part of your life.

  • Express gratitude

Gratitude is more than saying thank you. It's a sense of wonder, appreciation and, yes, thankfulness for life. It's easy to go through life without recognizing your good fortune. Often, it takes a serious illness or other tragic event to jolt people into appreciating the good things in their lives. Don't wait for something like that to happen to you.

Make a commitment to practice gratitude. Each day identify at least one thing that enriches your life. When you find yourself thinking an ungrateful thought, try substituting a grateful one. For example, replace "my sister forgot my birthday" with "my sister has always been there for me in tough times."

Let gratitude be the last thought before you go to sleep. Let gratitude also be your first thought when you wake up in the morning.

Cultivate optimism

Develop the habit of seeing the positive side of things. You needn't become a Pollyanna — after all, bad things do happen. It would be silly to pretend otherwise. But you don't have to let the negatives color your whole outlook on life. Remember that what is right about you almost always trumps what is wrong.

If you're not an optimistic person by nature, it may take time for you to change your pessimistic thinking. Start by recognizing negative thoughts as you have them. Then take a step back and ask yourself these key questions:

  • Is the situation really as bad as I think?
  • Is there another way to look at the situation?
  • What can I learn from this experience that I can use in the future?
Find your purpose

People who strive to meet a goal or fulfill a mission — whether it's growing a garden, caring for children or finding one's spirituality — are happier than those who don't have such aspirations.

Having a goal provides a sense of purpose, bolsters self-esteem and brings people together. What your goal is doesn't matter as much as whether the process of working toward it is meaningful to you.

Try to align your daily activities with the long-term meaning and purpose of your life. Research studies suggest that relationships provide the strongest meaning and purpose to your life. So cultivate meaningful relationships.

Are you engaged in something you love? If not, ask yourself these questions to discover how you can find your purpose:

  • What excites and energizes me?
  • What are my proudest achievements?
  • How do I want others to remember me?
Live in the moment

Don't postpone joy waiting for a day when your life is less busy or less stressful. That day may never come.

Instead, look for opportunities to savor the small pleasures of everyday life. Focus on the positives in the present moment, instead of dwelling on the past or worrying about the future.

References

See more In-depth

sexta-feira, 23 de janeiro de 2015

Wild west physics: Bridging the gap between the study of 'outer space' and 'inner space'

 

The Compact Muon Solenoid (CMS) pixel detector. The CMS is used to detect particles generated by collisions at the Large Hadron Collider particle accelerator. A University at Buffalo team is working to connect findings from particle acceleration experiments to findings in cosmology.

Call it macro-micro physics: the study of the huge paired with the study of the very, very small.

In a new National Science Foundation-funded project, University at Buffalo physicists are looking to bridge the gap between two related but distinctive fields: the study of "outer space" (stars and galaxies) and "inner space" (fundamental particles and forces).

That description is from UB Professor Will Kinney, one of the three scientists involved. His partners on the research are Associate Professor Dejan Stojkovic, the principal investigator, and Professor Doreen Wackeroth.

To explain their project further: In the moments after the Big Bang, when the universe was young, it was an incredibly hot, dense soup of matter and energy.

Today, physicists can study this unique time in history by creating a similar environment inside giant machines called particle accelerators, which slam teeny-tiny protons into one another to create even smaller particles. The accelerators are like a "time machine," enabling scientists to study the conditions of the baby universe, Wackeroth says.

This is just one way in which research on the huge (cosmology) and the miniscule (subatomic particles and particle acceleration) are connected.

Taken together, the two fields could provide answers to some of the most important questions in physics today: How did our universe begin? How do gravity and quantum mechanics relate to one another? And what is the role of the vacuum in space and time? The new project will advance knowledge in all of these areas.

"If you want to understand the macro -- the cosmos -- you have to understand the micro," Stojkovic says.

The hunt for 'exotic physics'

The team will be asking some bizarre questions.

For example, Stojkovic's portion of the research involves, among other things, a computer simulation called BlackMax that he created with colleagues. The program is what physicists call an "event generator," and it will help researchers investigate one of the great questions in science today: What is dark matter?

BlackMax shows what it would look like if a collision inside a particle accelerator generated various forms of "exotic physics" -- phenomena beyond what scientists have observed in the real world.

Researchers at the world's most powerful particle accelerator, the Large Hadron Collider, use BlackMax to determine if their collision experiments are producing any of the anomalies the program simulates, including components of string theory or mini black holes.

(If you're worried that such black holes could destroy the Earth, don't: Those that could be created at the Large Hadron Collider would have a lifetime of around 10 to the minus 27 seconds, "which is incredibly short," Stojkovic says. "They will practically disappear in a burst of particles before they have any chance to suck even a single atom. BlackMax describes this process very precisely.")

So how does this relate to the NSF-funded project's theme of using the small to investigate the big, and vice versa?

The answer is that the curiosities explored by BlackMax are directly connected to the study of the universe.

Here's how: Today's telescopes can only detect 4 percent of the stuff that makes up the cosmos. Scientists know the other 96 percent exists because it distorts space in a way that can be seen, but they don't know what it is. This missing, invisible stuff is called "dark matter" and "dark energy."

According to Stojkovic, "Dark matter could be entirely comprised of tiny primordial black holes which were formed naturally in the early universe" -- the types of tiny black holes modeled by BlackMax.

He says that while this possibility may seem unlikely, the time has come for asking strange questions.

"We need to ask strange questions, since nature sometimes uses logic superior to our own," Stojkovic says. "Some of the phenomena we are exploring with BlackMax may sound unusual and indeed may not exist. But if we never ask the question, we'll never find out. If we discover that they do exist, the implications will be enormous in terms of our understanding of our universe."

That's science: Many great discoveries and observed phenomena are totally bizarre. And if there were ever a time to explore odd possibilities, this is it.

When scientists launched the Large Hadron Collider in 2008, one major objective was to find the Higgs boson, an extremely important fundamental particle that had been predicted by scientists but never before observed. The Higgs was discovered at the facility in 2012, marking the success of one of the greatest scientific endeavors of our time.

However, a second goal of scientists working with the collider proved more elusive: They had hoped that the proton-proton collisions there would generate a new, never-before-seen zoo of particles, some of which would account for dark matter. But this has not happened, which suggests that physicists may be looking for the wrong thing, or need to improve their search strategies, Stojkovic says.

Enter BlackMax.

As the Large Hadron Collider gears up for a new season this spring after a two-year break for maintenance, the program will be assisting scientists in their quest for dark matter.

The UB researchers aren't suggesting that all of the possibilities they are examining truly exist. They are, in fact, expecting that their work could generate negative results, possibly helping to debunk exotic theories.

For the love of knowing

Why does this research matter?

It's a question that Stojkovic, Kinney and Wackeroth hear all the time. One answer is spin-offs: particle collider research has generated all sorts of new knowledge and machinery that could lead to advancements in fields from health care to computing. But at the heart of the matter is simple scientific curiosity -- the joy of discovery.

Kinney's portion of the new NSF-funded project will involve studying various models of the early universe, and explaining what new data from particle accelerators tells us about the properties of the infant cosmos. Wackeroth will be honing the accuracy of models showing what types of particles are produced at the Large Hadron Collider. To better understand the world around us -- the origins of our universe, and the smallest particles that make up the matter in the cosmos, on Earth and inside of each one of us -- is a worthwhile goal, the scientists say.

"It brings society to a higher level," Stojkovic says.

Kinney explains the importance of basic science this way: "Electricity was once considered a parlor trick. Five hundred years ago, when it was shown that the sun was at the center of the Solar System, it wasn't necessarily clear why this mattered. It turned out that this realization was the key that allowed Newton to develop his laws of motion, which form the basis of our entire technological society today.

"Now, we are again trying to understand the structure of the cosmos. The impact of what we're learning cannot be measured, but we know that the questions we are asking are important. Fundamental discoveries drive progress in society in unpredictable ways."

Review: The super-slim FoxL Dash7 Bluetooth speaker

 

 

The FoxL Dash7 Bluetooth speaker sure is slim at under an inch thick (Photo: Noel McKeegan...

The FoxL Dash7 Bluetooth speaker sure is slim at under an inch thick (Photo: Noel McKeegan/Gizmag.com)

Image Gallery (6 images)

We've come across Bluetooth speakers of all shapes and sizes here at Gizmag, and at first glance the FoxL Dash7 is hardly one to stand out from the crowd. But spending some time with Soundmatters' latest offering you come to appreciate what's inside. The Dash7 might not pack enough punch to keep the neighborhood up at night, but it really hits that sweet spot of great portability without compromising on high-quality sound.

Appearing inspired by a TV remote control, or perhaps an oversized chocolate bar, the lightweight design of the Dash7 speaker strikes you the moment you wrap your fingers around its 0.75 x 2.1 x 7.5 in (18 x 53 x 190 mm) frame. Weighing just 71 oz (201 g), the speaker can be slipped into a pocket or thrown in your backpack and you'll barely even notice its there.

But anyone can make a Bluetooth speaker that's small and light, right? What gives the Dash7 an edge over devices of similar size, at least the ones we've turned our ear to, is the clarity of its output right across a range of sounds. We've put it to the test on wooden desktops and the grass down at the park, streaming everything from The Staple Singers to Notorious BIG, and the audio remained nothing short of impressive for a speaker of its size.

The company puts this down to what it calls "Twoofers." This patented portmanteau pertains to flattened neodymium drivers that both "tweet" and "woof" and are claimed to deliver a "uniquely wide frequency range." The lower frequencies are boosted further by the Dash7's battery, which serves as a passive bass woofer.

You will hear the speaker begin to strain under the stress of more bass-heavy audio, which again, for a speaker this compact is a minor criticism and doesn't really come as a surprise. Soundmatters does offer a separate plug-in sub-woofer called foxLO, which it says combines with the Dash7 to better round out the frequency range.

One drawback is the size of the buttons, which are no bigger than the end of your pen and ...

One other drawback is the size of the buttons, which are no bigger than the end of your pen and sit flush along the face of the speaker. This makes operating the device a bit of a pain in the neck, unless you're two years old or have unhealthily long fingernails.

The speaker features a noise-canceling microphone, which affords it functionality as a speakerphone. It also comes accompanied by a folding stand, which allows you to sit the speaker on its edge for better-targeted audio, while also doubling as a protective carry case.

Connecting over Bluetooth LE, the Dash7 will work within 30 ft (9.1 m) of your mobile device and is recharged via an included Micro USB and wall adapter, with a charge lasting for around 12 hours of listening at a time.

The speaker also features a noise-cancelling microphone, which affords it functionality as...

The FoxL Dash7 is far from the cheapest Bluetooth speaker you can find, but at the same time isn't in the same league as big players like Bose, whose high-end Soundlink speakers will set you back between $300 and $400. The Dash7 is a speaker that strikes a good balance between a compact, mobile listening solution and providing clear and high-quality audio – and to us, the $200 price tag seems about right.

Source: Soundmatters

 

Self-powered intelligent keyboard could provide a new layer of security

 

"This intelligent keyboard changes the traditional way in which a keyboard is used for information input," said Zhong Lin Wang, a Regents professor in the School of Materials Science and Engineering at the Georgia Institute of Technology. "Every punch of the keys produces a complex electrical signal that can be recorded and analyzed."

Conventional keyboards record when a keystroke makes a mechanical contact, indicating the press of a specific key. The intelligent keyboard records each letter touched, but also captures information about the amount of force applied to the key and the length of time between one keystroke and the next. Such typing style is unique to individuals, and so could provide a new biometric for securing computers from unauthorized use.

In addition to providing a small electrical current for registering the key presses, the new keyboard could also generate enough electricity to charge a small portable electronic device or power a transmitter to make the keyboard wireless.

An effect known as contact electrification generates current when the user's fingertips touch a plastic material on which a layer of electrode material has been coated. Voltage is generated through the triboelectric and electrostatic induction effects. Using the triboelectric effect, a small charge can be produced whenever materials are brought into contact and then moved apart.

"Our skin is dielectric and we have electrostatic charges in our fingers," Wang noted. "Anything we touch can become charged."

While the self-powered feature could provide a convenience benefit and potentially eliminate the need for batteries in wireless keyboards, Wang believes the major impact of the device may be in helping to secure computers by using individual typing patterns or habits as a biometric.

"This has the potential to be a new means for identifying users," he said. "With this system, a compromised password would not allow a cyber-criminal onto the computer. The way each person types even a few words is individual and unique."

To evaluate the authentication potential of the keyboard, the research team asked 104 persons to type the word "touch" four times, and recorded the electrical patterns produced. Using signal analysis techniques, they were able to differentiate individual typing patterns with low error rates, Wang said.

Instead of individual mechanical keys as in traditional keyboards, Wang's intelligent keyboard is made up of vertically-stacked transparent film materials. Researchers begin with a layer of polyethylene terephthalate between two layers of indium tin oxide (ITO) that form top and bottom electrodes.

Next, a layer of fluorinated ethylene propylene (FEP) is applied onto the ITO surface to serve as an electrification layer that generates triboelectric charges when touched by fingertips. FEP nanowire arrays are formed on the exposed FEP surface through reactive ion etching.

The keyboard's operation is based on coupling between contact electrification and electrostatic induction, rather than the traditional mechanical switching. When a finger contacts the FEP, charge is transferred at the contact interface, injecting electrons from the skin into the material and creating a positive charge.

When the finger moves away, the negative charges on the FEP side induces positive charges on the top electrode, and equal amounts of negative charges on the bottom electrode. Consecutive keystrokes produce a periodic electrical field that drives reciprocating flows of electrons between the electrodes. Though eventually dissipating, the charges remain on the FEP surface for an extended period of time.

Wang believes the new smart keyboard will be competitive with existing keyboards, in both cost and durability. The new device is based on inexpensive materials that are widely used in the electronics industry.

As part of the study, his research group evaluated the keyboard under challenging conditions, including application of moisture, dirt and oil. "You could pour coffee on the keyboard, and it would not be damaged," said Wang. "Because it is based on a sheet of plastic, liquids will not hurt it."

The research was reported December 30 online in the journal ACS Nano. It was sponsored by the U.S. Department of Energy's Office of Basic Energy Sciences.

In addition to Wang, the research team included first author Jun Chen from Georgia Tech's School of Materials Science and Engineering; Guang Zhu from the Beijing Institute of Nanoenergy and Nanosystems; Jin Yang from Chongqing University; Qingshen Jing, Peng Bai, Weiqing Yang, and Yuanjie Su from Georgia Tech; and Xuewi Qi from the University of California, Riverside.

This material is based on work supported by the U.S. Department of Energy under award DE-FG02-07ER46394.

40 Rare and Important Archaeological Finds of all time

 

 

“The past is a foreign country; they do things differently there.”

The past can be both shocking and familiar. It’s common to say that human nature never changes – but it’s still possible for archaeology to surprise us, by pulling things from the ground which transform our conception of the past.

1. Rosetta Stone

Top archaeological finds of all time

The rediscovery of the Rosetta Stone in 1799 during the French expedition to Egypt effectively began modern Egyptology by repeating a decree issued in 196BC on behalf of King Ptolemy in Ancient Greek and Demotic as well as in hieroglyphs. The stone, a stele that was used as a building material during the Middle Ages, was captured by the British in 1801 and taken to the British Museum a year later, where it remains to this day.

2. Dead Sea Scrolls

Top archaeological finds of all time

The Dead Sea Scrolls are almost 1,000 biblical manuscripts discovered in the decade after World War 2 in what is now the West Bank. The texts, mostly written on parchment but also on papyrus and bronze, are the earliest surviving copies of biblical and extra-biblical documents known to be in existence, dating over a 700-year period around the birth of Jesus. The ancient Jewish sect the Essenes is supposed to have authored the scrolls, written in Hebrew, Aramaic and Greek, although no conclusive proof has been found to this effect.

3. Pompeii

Pompeii

Pompeii, the ancient Roman city, was buried during a volcanic eruption in 79 AD when Mount Vesuvius exploded. It was lost for nearly 1700 years and the damage done to the city was so severe that even the name of the city vanished from memory. In 1738 Herculaneum – a nearby city also lost – was discovered and then ten years later military engineer Rocque Joaquin de Alcubierre discovered Pompeii. Whilst digging in later excavations, Giuseppe Fiorelli discovered that some of the large bubbles in the volcanic mud were perfectly formed molds of the men who had died there. He injected plaster into the bubbles and gave the modern world the first look at real Ancient Roman people. Interestingly the city was full of erotic art and objects (many of which were hidden until 2000 AD) and graffiti found on a wall in Pompeii called the city “Sodom and Gomorrah” leading many Christians to believe that the city was destroyed by God in retribution for its sexual perversities.

4. The Cave of Altamira

Top archaeological finds of all time

When the Cave of Altamira was first discovered it was to unleash a worldwide controversy spanning decades. In this cave, amateur archeologist Marcelino Sanz de Sautuola, led by his twelve year-old daughter, saw for the first time since paleolithic times, artworks created by man previously thought to be incapable of such a feat. Its implications for sociology and archeology were astounding. When the paintings were finally verified as authentic 20 years later, it changed forever the perception of prehistoric human beings. It is hard to fathom how Sautuola must have felt the moment he first glimpsed the paintings.

5. Tutankhamun

Top archaeological finds of all time

“At first I could see nothing, the hot air escaping from the chamber causing the candle flame to flicker, but presently, as my eyes grew accustomed to the light, details of the room within emerged slowly from the mist, strange animals, statues, and gold – everywhere the glint of gold. For the moment – an eternity it must have seemed to the others standing by – I was struck dumb with amazement.” Those are the words of Howard Carter – the man who discovered King Tut’s tomb. They sum up far better than I can the marvelousness of this most important Egyptian discovery in modern times. The importance of this discovery to the understanding of Ancient Egyptian history is probably the greatest ever.

6. Mother goddesses

Top archaeological finds of all time

One of the oldest statues ever discovered depicts an obese woman with swollen breasts. The Willendorf Venus was discovered in Austria, and is 26,000 years old. It is highly unlikely that any member of an ancient society would be so overfed as to be obese, and so the statues are symbolic rather than representative.

These figures were most likely carved to represent motherhood. The presence of rotund figurines in many ancient sites suggests that the earliest-known religious practices were related to the worship of femininity.

7. Knossos

Incredible Archaeological Discoveries

It is not often that archaeological digs can provide evidence for an entirely new civilisation, but that was exactly the result of work by Cretan antiquarian Minos Kalokairinos and his British counterpart Arthur Evans at the end of the 19th century. They unearthed the palace at Knossos, supposedly the site of the Minotaur’s labyrinth from Greek myth.

8. Antikythera Mechanism

Top archaeological finds of all time

In 1901 an ancient shipwreck was discovered by sponge divers off the coast of the Greek island of Antikythera. The construction has been dated to the early 1st century BC. Amongst the finds of typical trade goods such as statues and flasks was found a fused mass of metal. For almost a hundred years after its discovery, the mechanism was regarded as a simple curiosity.

It is now regarded as an early precursor to the computer. The various cogs and wheels of the mechanism are able to calculate where stars and planets should appear in the night sky. This discovery shows not only a keen understanding of the motion of the heavens but also the ability to replicate those movements on an artificial structure. It suggests a mechanistic understanding of the universe which points to the development of science as the best way to deal with the world around us.

9. The Pilate Stone

Top archaeological finds of all time

The Pilate stone (probably the least-known object on this list) was discovered in June of 1961 near Caesarea (part of Judea) by Dr. Antonio Frova while he was excavating with his team of archeologists an Ancient Roman theater built by Herod the Great in 30BC. The stone had been reused in the fourth century as part of a new staircase that had been added later. What was significant about this stone was what the archeologists found inscribed on the side: “To the Divine Augusti [this] Tiberieum … Pontius Pilate … prefect of Judea … has dedicated [this]“. This was the first time physical evidence had been found for the existence of the Biblical Pontius Pilate. Its authenticity is universally recognized by the archaeological world.

10. Olduvai Gorge

Incredible Archaeological Discoveries

The Olduvai Gorge runs through Eastern Africa and is probably the most important archeological location on Earth. It contains the remains of 1.9 million year-old humans and, because it was continually occupied for thousands of years, shows the progress of the evolution of man. There have been found tools, evidence of scavenging (human teeth marks on bones instead of cut marks) and hunting, as well as evidence for human social interaction at such an early age. There are also rock art formations in the area. Because of the amount of the remains and signs of human interaction, it was very possibly one of man’s first cities (so to speak).

11.  Hagar Qim

Incredible Archaeological Discoveries

When you think of the oldest buildings in the world your mind may immediately go to the Pyramids, or maybe Stonehenge, but in fact the Megalithic temples of Malta are the oldest free-standing structures on the planet. Ħaġar Qim and four other Maltese megalithic structures date back to between 3,600 and 3,200 BCE. They were first excavated and explored in the mid-19th century.

12. The Terracotta Army in Xi’an

Incredible Archaeological Discoveries

The funerary army of the first emperor of China, Qin Shi Huang, dating to the third century BCE was discovered by a group of farmers in Xi’an in 1974. More than 8,000 life-sized soldiers, 130 chariots and 150 separate horses, not to mention countless officials and courtesans, have since been documented, although the majority remain buried underground near the emperor’s mausoleum. It remains one of the most spectacular man-made sites in the world.

13. Tomb of Philip II of Macedon

Incredible Archaeological Discoveries

Vergina is a small town in northern Greece, located in the peripheral unit of Imathia, Central Macedonia.  The town became internationally famous in 1977, when the Greek archaeologist Manolis Andronikos unearthed what he claimed was the burial site of the kings of Macedon, including the tomb of Philip II, who is the father of Alexander the Great.  In 1977, Andronikos undertook a six-week study near Vergina and found four buried chambers, which he identified as undisturbed tombs. Three more tombs were found in 1980.

14. Staffordshire hoard

Incredible Archaeological Discoveries

The largest hoard of Anglo-Saxon precious metalwork was found just four years ago in a field near Lichfield, in Staffordshire. More than 3,500 martial items made from gold or silver dated back to the kingdom of Mercia in the seventh and eighth centuries were excavated, with experts describing the hoard as of equal or more importance than the Sutton Hoo discoveries.

15. Baghdad batteries

Top archaeological finds of all time

In the ruins of Mesopotamia, jars were found containing iron cylinders and copper spikes. They were created during the dynasties of Parthian or Sassanid period (the early centuries AD), and probably discovered in 1936 in the village of Khuyut Rabbou’a, near Baghdad, Iraq. They are still a mystery, but speculation has brought some interesting theories. These jars were filled with acidic grape juice, voltage may have been produced. Modern reconstructions of the jars have shown that enough voltage would have been produced to allow electrical use – but at this stage, more evidence is needed. If correct, the artifacts would predate Alessandro Volta’s 1800 invention of the electrochemical cell by more than a millennium.

16. Roman dodecahedra

Top archaeological finds of all time

Sometimes archaeologists discover an artifact whose purpose is a complete mystery – but it is rare for a whole class of artifacts to remain unknown. All over the Roman world, small metal dodecahedra (date from the 2nd or 3rd centuries CE)  with circles cut in their faces have been discovered – yet it is unknown what they were originally used for. Some suggest they were used as candle holders (unlikely in an age where oil lamps were the norm), while others think they might have been aids for judging distance.

17. Ancient antibiotics

Top archaeological finds of all time

Scientific antibiotics are about seventy years old. But bones have been found in Nubia – dating from 550AD – which show traces of tetracycline, an antibiotic still used today.

How did people use an antibiotic more than a thousand years before it was discovered? Tetracycline is produced by yeast – and yeast can be used to produce beer. It seems that the ancient Nubians – including their infant children – drank beer as a medicine.

18. Stone spears

Top archaeological finds of all time

At the Southern tip of South Africa, sharp stone fragments – perfectly suited for spear tips – were discovered. They were 200,000 years old – and suggested that humans were hunting for their food much longer ago than had been thought possible. Some evidence suggests that humans may have been hunters even earlier than this: remnants of cooking fires have been found dating up to one million years old.

19. Ancient Chemical Warfare

Incredible Archaeological Discoveries

In 1933 archaeologist Robert du Mesnil du Buisson was searching beneath the ruins of an ancient Roman/Persian battlefield when he came across some siege tunnels that had been dug under the city. In the tunnels he found the bodies of 19 Roman soldiers that seemingly died while trying to desperately escape from something and one Persian soldier clutching his chest. Apparently when the Romans heard the Persians digging under their walls they began digging a tunnel of their own with the idea of dropping in on the Persians from above. The trouble for them was that the Persians heard it and set a trap. As soon as the Roman soldiers dropped through they were met with burning sulfur and bitumen which has the unfortunate effect of turning to acid in your lungs.

20. Diquis Spheres

Incredible Archaeological Discoveries

Known as the stone spheres of Costa Rica, scientists believe these nearly perfect speres were carved around the turn of the millennium. Although there is much speculation as to what they may have been used for, no one is completely sure.

21. Wonders of Sanxingdui

Incredible Archaeological Discoveries

The  archaeological site of Sanxingdui, China is a Bronze Age site (circa 2800 to 800 B.C.) located in the town of Guanghan of Sichuan Province .

Sanxingdui is recognized as one of the most important ancient remains in the world for its vast size, lengthy period and enriched cultural contents.

The first Sanxingdui relics were discovered by a farmer in 1929 and excavation has continued ever since. During this period, generations of archaeologists have worked on the discovery and research of the Sanxingdui culture. In 1986, two major sacrificial pits were found and they aroused widespread academic attention around the world.

The Sanxingdui finds are exciting, but they remain enigmatic. No texts have been found, nor is there any mention of this culture in the records of other countries.

The artifact assemblage recovered from this site includes an enormous number of bronze, jade, gold, pottery and bone, discovered in ten caches. The two richest contained more than 1100 artifacts. Analysis of lead and other elements in the bronzes indicates sources similar to those of other cultures along the lower reaches of the Yangtze River. At this point, however, the unique culture that produced these artifacts remains a mystery.

via: china.org.cn

22. Rapa Nui

Incredible Archaeological Discoveries

Popularly known as Easter Island, this is one of the most isolated places in the world, thousands of miles off of the Chilean coast in the South Pacific. The most baffling thing about the island, however, isn’t the fact that humans even managed to find and settle it but that they then proceeded to construct enormous stone heads around the island.

23. Piri Reis Map

Incredible Archaeological Discoveries

Dating to the early 1500s this map shows the coastlines of South America, Europe, and Africa with amazing precision. Apparently it was constructed by general and cartographer Piri Reis (hence the name) from the fragments of dozens of others.

24. Nazca Lines

Incredible Archaeological Discoveries

Although they were literally beneath the feet of archaeologists for hundreds of years, the Nazca Lines weren’t discovered until the early 1900′s for the simple reason that they are nearly impossible to see unless you are directly above them. While there have been numerous explanations ranging from UFO’s to technically advanced ancient civilization, the most probable explanation is that the Nazca people were excellent surveyors, although why they would construct such enormous geoglyphs remains a mystery.

25. Mount Owen Moa

Incredible Archaeological Discoveries

In 1986 an expedition was making its deeper and deeper into the cave system of Mount Owen in New Zealand when it came across the huge claw you’re now looking at. It was so well preserved that it almost seemed like whatever it belonged to had just died recently. Upon excavation and inspection, however, it was determined to belong to an Upland Moa, a large prehistoric bird that apparently came with a nasty set of claws.

26. Voynich Manuscript

Incredible Archaeological Discoveries

Described as the “world’s most mysterious manuscript” this piece of literature has been dated back to early 15th century Italy. With most of its pages filled with what seems to be herbal recipes, none of the plants match known species and the language remains undecipherable.

27. Gobekli Tepe

Incredible Archaeological Discoveries

Although at first glance it may seem like nothing more than a bunch of rocks, this ancient settlement discovered in 1994 was constructed roughly 9,000 years ago and is currently the one of the oldest examples of complex/monumental architecture in the world, predating the pyramids by thousands of years.

28. Sacsayhuaman

Incredible Archaeological Discoveries

This walled complex just outside of Cusco, Peru is part of what used to be the capital of the Inca Empire. The crazy part about this wall, however, is in the details of its construction. The rock slabs fit together so tightly that it would be impossible to slide even a hair between them. It’s a testament to the precision of ancient Incan architecture.

29. Headless Vikings of Dorset

Incredible Archaeological Discoveries

While digging a railroad in Dorset workers came across a small contingent of viking warriors buried in the ground, all missing their heads. At first archaeologists thought that maybe some villagers had survived a raid and exacted their revenge but upon closer inspection things got a little less clear. The beheadings looked too clean and seemed to have been done from the front rather than the back. They are still not sure what happened.

30. The Tomb of Sunken Skulls

Incredible Archaeological Discoveries

While excavating a dry lake bed in Motala, Sweden archaeologists came across several skulls that had stakes driven directly through their craniums. As if that weren’t bad enough one of the skulls even had pieces of the others skulls crammed up inside it. Whatever happened there 8,000 years ago wasn’t pretty.

31. Marcahuasi

Incredible Archaeological Discoveries

Marcahuasi is a plateau in the Andes Mountains located east of Lima, Peru.  The area rises over the Rimac River.  In 1952, a man named Daniel Ruzo made a remarkable discovery in the area.  He found hundreds of stone figures that resemble human faces and animals, some 90 feet tall.  The most famous formation was called The Monument to Humanity because it purportedly shows the major human races of the world.  The mountain sized rock formations of Marcahuasi have created controversy in the scientific world.  Many educated people have claimed that the structures were formed by natural erosion.

Rare Discovery

Some of the famous rock formations at Marcahuasi include the goddess Thueris the Anfichelidia, the valley of the seals, the lion of Africa, the vicuna, and the frog.  After discovering the area, Daniel Ruzo made some bizarre accusations surrounding Marcahuasi.  He wrote that the sculptures were made ??by a culture named “Masma” or “Fourth Humanity” almost 10.000 years ago.  According to Ruzo, every 8,500 years the planet Earth suffers disruptions that threaten the existence of all living beings.  Ruzo published articles stating that Marcahuasi was the site selected to preserve the knowledge of humanity.  Man-made or not, Marcahuasi remains a remarkable archeological discovery that has become a popular tourist destination.

32.  Rat King

Incredible Archaeological Discoveries

Rat kings are formed when a number of rats become intertwined at their tails and get stuck together with blood, dirt, ice, excrement or simply knotted.  The animals grow together forming one large beast.  The earliest report of a rat king comes from 1564.  Historically, the rat king was viewed as a bad omen, and probably with good reason.  Rats carry a number of diseases, perhaps most notably plague, so it is understandable that people would associate bad luck with a large cluster of rats.  Diseases tend to arise more readily when animals are confined close together, so the location of a rat king could be a breeding ground of disease.

Rare Discovery

Specimens of purported rat kings are rare and kept in some museums.  The largest well-known mummified rat king was found in 1828 in a miller’s fireplace at Buchheim, Germany.  It consists of 32 rats.  The rat king is currently located in the museum Mauritianum in Altenburg (Thuringia).  In 1930, a specimen was found in New Zealand that is displayed in the Otago Museum in Dunedin.  It was composed of immature Rattus rattus whose tails were entangled by horse hair.  Relatively few rat kings have been discovered in history.  Depending on the source, the number of reported instances varies between 35 and 50 finds.

The occurrence is particularly associated with Germany, where the majority of rat kings have been located.  In April 1929, a group of young forest mice was reported joined in Holstein, Germany, and there have been sightings of squirrel kings.  Most rat kings show formations of callus at the fractures of their tails, which according to proponents show that the animals survived for an extended period of time with their tails tangled.  A mummified rat king can help provide an understanding of the movement of rat populations.  Sightings have been sporadic in modern history, with some rat kings being reported alive.  The most recent claim comes from an Estonian farmer’s discovery in the Võrumaa region on January 16, 2005.

33.  Sea of Galilee Boat

Incredible Archaeological Discoveries

The Sea of Galilee Boat is an ancient fishing boat from the 1st century CE (the time of Jesus Christ), discovered in 1986 on the north-west shore of the Sea of Galilee in Israel.  The remains of the boat were found by brothers Moshe and Yuval Lufan, fishermen from Kibbutz Ginnosar.  The brothers are amateur archaeologists with an interest in discovering artifacts from Israel’s past.  They found the ship after a drought reduced the water-level of the lake.  The men reported their discovery to the authorities who sent out a team of archaeologists to investigate.

Rare Discovery

Realizing that the remains of the boat was of tremendous historical importance to Jews and Christians alike, a secret archaeological dig followed, undertaken by members of Kibbutz Ginosar, the Israel Antiquities Authority, and numerous volunteers.  The boat measures at 27 feet (8.27 meters) long, 7.5 feet (2.3 meters) wide and with a maximum preserved height of 4.3 feet (1.3 meters).  Excavating the boat from the mud without damaging it was a difficult process that lasted 12 days and nights.  The boat was then submerged in a chemical bath for 7 years before it could be displayed at the Yigal Allon Museum in Kibbutz Ginosar.

The Sea of Galilee boat is made primarily of cedar planks joined together by pegged mortise-and-tenon joints and nails.  It has ten different wood types, suggesting either a wood shortage or that it was made of scrap wood.  The boat is historically important to Jews because it is an example of the type of boat used by their ancestors in the 1st century.  Previously only references made by Roman authors, the Bible and mosaics have provided archeologists insight into the construction of these types of vessels.  The boat is also important to Christians because it was the type of vessel that Jesus and his disciples used, several of whom were fishermen

34. Andrewsarchus

Incredible Archaeological Discoveries

Roy Chapman Andrews was an American explorer, adventurer and naturalist who became the director of the American Museum of Natural History.  He is primarily known for leading a series of expeditions through the fragmented China into the Gobi Desert and Mongolia.  In the summer of 1923, Andrews began his third Asiatic expedition in the Gobi Desert, while in Mongolia, a member of his team named Kan Chuen Pao discovered an enormous skull of an unidentified mammal.  The lower jaw of the creature was not found.  After investigation, the mammal was given the classification of Andrewsarchus mongoliensis.

Rare Discovery

Andrewsarchus lived during the Eocene epoch, roughly 45 and 36 million years ago.  They had a long snout with large, sharp teeth and flat cheek teeth that may have been used to crush bones.  Because Andrewsarchus is only known from a single skull, whether it was an active predator or merely a large scavenger is open to debate.  The artifact is an enormous skull (32.8 in/83 cm long and 22/56 cm wide).  If Andrewsarchus was proportioned in the same manner as Mesonyx obtusidens, it had a length from the snout to the back of the pelvis of about 11 feet (3.4 m) and a height from the ground to the shoulder or middle of the back of about 6 feet (1.8 m). In round numbers, it is possible that the creature may have been the largest land-dwelling carnivorous mammal known.  The cranium is twice the length of a modern Alaskan brown bear and about triple the length of an American wolf.

Studies have placed Andrewsarchus in the 1000 kg (2200 lb) size range, but if the animals were robust, some specimens might have weighed up to 4000 pounds.  The appearance and behavioral patterns of Andrewsarchus are virtually unknown and have been the topic of debate among paleontologists ever since it was first discovered.  Andrewsarchus possessed some of the strongest jaws ever evolved in a land mammal, well able to bite through large bones if needed.  Andrewsarchus may have fed on beached primitive whales, shellfish and hard-shelled turtles, as well as contemporary large mammals.  The creatures were related to cloven-hoofed animals, such as pigs and deer, so they probably had hooves rather than paws.

35. Teotihuacan Sacrifice

Incredible Archaeological Discoveries

Although it has been known for years that the Aztecs hosted numerous bloody sacrificial festivals, in 2004 a grisly discovery was made outside of modern day Mexico City. Numerous decapitated and mutilated bodies of both humans and animals shed some light on just how horrific the rituals could get.

36. The Grauballe Man

Incredible Archaeological Discoveries

It’s not a strange occurrence for mummified bodies to be found in bogs but this body, now known as the Grauballe Man, is a bit unique. Not only is he amazingly well preserved with his hair and fingernails still intact, it is possible to reconstruct his demise from the information found on and around his body. Judging from a large wound wrapping around his neck from ear to ear it seems he was sacrificed, probably in an attempt to turn a better harvest.

37.  The Venetian Vampire

Incredible Archaeological Discoveries

Although these days the most surefire method used to slay vampire is a stake through the heart, hundreds of years ago that was not considered sufficient. The ancient alternative – the brick through the mouth. Think about it. What’s the easiest way to keep a vampire from sucking blood? Cram his face full of cement no doubt. The skull you are looking at here was found by archaeologists just outside Venice in a mass grave.

38. Uluburun Shipwreck

Incredible Archaeological Discoveries

The Uluburun shipwreck is a Late Bronze Age shipwreck dated to the 14th century BCE.  It was discovered off Uluburun (Grand Cape) situated about 6 miles southeast of Ka?, in south-western Turkey.  The wreck was first discovered in the summer of 1982 by Mehmed Çakir, a local sponge diver from Yalikavak, a village near Bodrum.  Between the years of 1984 to 1994, eleven consecutive campaigns took place totaling 22,413 dives, and revealing one of the most spectacular Bronze Age treasure troves ever discovered in the Mediterranean Sea.  On its final journey, the Uluburun ship was sailing to the region west of Cyprus.  The objects aboard the ship range from northern Europe to Africa, as far west as Sicily, and as far east as Mesopotamia, exhibiting products of nine or ten different cultures.

Rare Discovery

The ship, which was about 50 feet long, was built of cedar in the ancient shell-first tradition, with pegged tenon joints securing planks to each other and to the keel.  Some of the hull planks were preserved under the cargo.  They were fastened with pegged mortise-and-tenon joints.  Upon discovery, there has been a detailed examination of Uluburun’s hull, but unfortunately no evidence of its framing.  The ship carried 24 stone anchors, which are of a type almost completely unknown in the Aegean.  The Uluburun ship’s cargo consisted mostly of raw materials and trade items.

The artifacts discovered include copper cargo totaling ten tons, approximately 175 glass ingots of cobalt blue turquoise and lavender, ivory in the form of whole and partial elephant trunks, hippopotamus teeth, Cypriot pottery, a ton of terebinthine resin in amphorae, a large collection of gold artifacts, ebony logs from Egypt, and ancient weapons.  The ship carried one ton of tin.  The tin from Uluburun is, at this time, the only pre-Roman tin with a reasonable provenance.  The Uluburun shipwreck has fed into virtually every aspect of research on trade and society in the Late Bronze Age Aegean and Levant.  It has helped historians understand the intensity of commercial trade during the Late Bronze Age.

39. Ardi

Incredible Archaeological Discoveries

Ardi is the designation of the fossilized skeletal remains of a female Ardipithecus ramidus, an early human-like species 4.4 million years old.  It is the most complete early hominid specimen in existence, with most of the skull, teeth, pelvis, hands and feet intact.  Fossils of Ardi were first found in Ethiopia in 1994, but it took 15 years for scientists to assess their significance.  Ardi is a more complete set of remains than the Australopithecus Lucy, which was discovered in 1974.  She is a more primitive hominid standing at 4 feet (120 cm) tall and weighing around 110 pounds (50 kg), Ardi was about 6 inches taller than Lucy but almost double her weight.  The skeleton was discovered at a site called Aramis in the arid badlands near the Awash River in Ethiopia.

Rare Discovery

Ardi has feet that are better suited for walking than chimpanzees.  Her canine teeth are smaller than humans, and equal in size between males and females.  This suggests reduced male-to-male conflict, pair-bonding, and increased parental investment among species.   ”Thus, fundamental reproductive and social behavioral changes probably occurred in hominids long before they had enlarged brains and began to use stone tools.”  The remains shows evidence of small skull capacity akin to that of apes and a bipedal upright walk akin to that of humans, providing further evidence supporting the view that bipedalism preceded increase in brain size in human evolution.  Researchers have inferred from the form of Ardi’s limbs and the presence of her opposable big toe that she was a facultative biped, bipedal when moving on the ground, but quadrupedal when moving in trees.

In trees, Ardi was nothing like modern apes.  Modern chimps and gorillas have evolved limb anatomy specialized to climbing vertically up tree trunks, hanging and swinging from branches, and knuckle-walking on the ground.  The wrists and finger joints of Ardi were highly flexible.  As a result she would have walked on her palms as she moved in the trees.  Wear patterns and isotopes have suggested a diet that includes fruits, nuts, and other forest foods.  On October 1, 2009, the journal Science published an open-access collection of eleven articles, detailing many aspects of A. ramidus and its environment.  “What Ardi tells us is there was this vast intermediate stage in our evolution that nobody knew about,” said Owen Lovejoy, an anatomist at Kent State University in Ohio.

40. The Baby Disposal

Incredible Archaeological Discoveries

One thing you will realize by the end of this list is that people, at least in the past, were very fond of cannibalism, sacrifice, and torture. As a case in point, not long ago as several archaeologists were searching through the sewers beneath a Roman/Byzantine bathhouse in Israel when they came across something terrifying…baby bones, and lots of them. For whatever reason someone in the bathhouse above apparently felt compelled to dispose of hundreds of babies in the sewer below.

source : www.moco.choco.com