segunda-feira, 24 de novembro de 2014

Don't get hacked! Research shows how much we ignore online warnings

 


For their study, BYU researchers created this screen to simulate hacking into participants' laptops.

Say you ignored one of those "this website is not trusted" warnings and it led to your computer being hacked. How would you react? Would you:

A. Quickly shut down your computer?

B. Yank out the cables?

C. Scream in cyber terror?

For a group of college students participating in a research experiment, all of the above were true. These gut reactions (and more) happened when a trio of Brigham Young University researchers simulated hacking into study participants' personal laptops.

"A lot of them freaked out -- you could hear them audibly make noises from our observation rooms," said Anthony Vance, assistant professor of Information Systems. "Several rushed in to say something bad had happened."

Fortunately for the students, nothing bad had really happened. What they saw -- a message from an "Algerian hacker" with a laughing skull and crossbones, a 10-second countdown timer and the words "Say goodbye to your computer" -- wasn't real. What was real was that all of the participants got the message by ignoring web security warnings.

Vance and BYU colleagues Bonnie Anderson and Brock Kirwan carried out the experiment to better understand how people deal with online security risks, such as malware. They found that people say they care about keeping their computers secure, but behave otherwise -- in this case, they plowed through malware warnings.

"We see these messages so much that we stop thinking about them," Vance said. "In a sense, we don't even see them anymore, and so we often ignore them and proceed anyway."

For the study, researchers first asked participants how they felt about online security. Then, in a seemingly unrelated task, participants were told to use their own laptops to log on to a website to categorize pictures of Batman as animated or photographed. (Students were told their image classification project was being used to check the accuracy of a computer algorithm to do the same task.)

As participants clicked through the image pages, warning signs would randomly pop up indicating malware issues with the site they were accessing. If they ignored the message enough times, they were "hacked."

"A lot of people don't realize that they are the weakest link in their computer security," said Kirwan, assistant professor of Psychology and Neuroscience at BYU. "The operating systems we use have a lot of built-in security and the way for a hacker to get control of your computer is to get you to do something."

Kirwan's role in the research added another fascinating layer: Using his expertise in neuroscience, Kirwan carried out an additional experiment on subjects using EEG machines to measure brain responses to risk.

While results showed that people say they care about web security but behave like they don't; they do behave in-line with what their brains say. In other words, people's brainwaves better predict how risky they are with online security.

"We learned that brain data is a better predictor of security behavior than a person's own response," Vance said. "With neuroscience, we're trying to understand this weakest link and understand how we can fortify it."

Anderson, an associate professor of Information Systems, echoed the need to do so, quoting security expert Bruce Schneier: "Only amateurs attack machines; professionals target people."

When vaccines are imperfect: What math can tell us about their effects on disease propagation

 

November 20, 2014

Society for Industrial and Applied Mathematics

The control of certain childhood diseases is difficult, despite high vaccination coverage in many countries. One of the possible reasons for this is 'imperfect vaccines,' that is, vaccines that fail either due to 'leakiness,' lack of effectiveness on certain individuals in a population, or shorter duration of potency. In a new article, authors use a mathematical model to determine the consequences of vaccine failure and resulting disease dynamics.


The control of certain childhood diseases is difficult, despite high vaccination coverage in many countries. One of the possible reasons for this is "imperfect vaccines," that is, vaccines that fail either due to "leakiness," lack of effectiveness on certain individuals in a population, or shorter duration of potency.

In a paper publishing in the SIAM Journal on Applied Mathematics, authors Felicia Magpantay, Maria Riolo, Matthieu Domenech de Celles, Aaron King, and Pejman Rohani use a mathematical model to determine the consequences of vaccine failure and resulting disease dynamics.

"We examined the effects of individual-level vaccine failure on the propagation of a disease through a population," says author Felicia Magpantay. "Specifically, we took into account different ways in which vaccines may fail. We distinguished between vaccine-induced immunity that is 'leaky', whereby vaccination reduces the probability of infection upon exposure but does not eliminate it; 'all-or-nothing', which leads to perfect protection in some individuals, but none in others; and 'waning', which reflects transient protection--or some combination of all three."

While leakiness, degree and duration of coverage have direct effects at the individual level, the protection from imperfect vaccines and reduced disease transmission at the population level is not easy to determine. "By carefully ensuring a like-with-like comparison of the differences in the mechanism of vaccine failure, we identified distinct epidemiological signatures at the population-level and explored their implications for disease control," Magpantay explains.

The group of professional applied mathematicians considers a systematic analysis based on the "susceptible-infectious-recovered" model used in epidemiological studies. This model allows one to calculate the number of susceptible, infectious and recovered individuals in a population, factoring in infection and recovery rates as well as contact between susceptible and infected individuals. The authors adapt this model with an added vaccine component to compare the dynamics of the three aforementioned types of imperfect vaccines.

The critical proportion of the model population that needs to be vaccinated in order to drive the disease to extinction is seen to be the same in all three cases. When vaccination coverage is maintained below the critical ratio, the disease remains endemic in the population at a higher level for leaky vaccines, compared to the other two imperfect vaccines. "Among vaccines that exhibit the same level of individual-level effectiveness, the purely leaky vaccine always leads to the highest prevalence of infection in the long run. The purely all-or-nothing and purely waning vaccines lead to the same levels of prevalence," Magpantay elaborates.

The authors then extend their ordinary differential equation model to account for age distribution in the population using a system of partial differential equations for age-specific transmission. "The age distribution of the infected class depends on the type of vaccine failure, the age-specific contact rates and the vaccine coverage. In the cases that we have considered, the waning vaccine leads to the highest mean age of first infection," Magpantay says.

The authors also show that the three imperfect vaccines have distinct transient dynamics following the initiation of vaccination in a population. "Numerical simulations suggest that vaccination with leaky and waning vaccines can bring about a long honeymoon period: a temporary period of low disease prevalence after the onset of mass vaccination," Magpantay explains. "This provides an alternative explanation for the observed resurgence of some diseases like pertussis in regions that maintain high vaccination coverage." All-or-nothing vaccines appear to show a more stable transition.

Topics for future work include examining the role of seasonality on transmission rates as well as the effect of a vaccine on infectiousness of an individual.


Story Source:

The above story is based on materials provided by Society for Industrial and Applied Mathematics. Note: Materials may be edited for content and length.


Journal Reference:

  1. F. M. G. Magpantay, M. A. Riolo, M. Domenech de Cellès, A. A. King, P. Rohani. Epidemiological Consequences of Imperfect Vaccines for Immunizing Infections. SIAM Journal on Applied Mathematics, 2014; 74 (6): 1810 DOI: 10.1137/140956695

Update on new treatments for liver diseases

 


Cirrhosis and nonalcoholic fatty liver disease (NAFLD) are two serious liver conditions with limited pharmacological treatments. The December issues of AGA's journals -- Clinical Gastroenterology and Hepatology and Gastroenterology -- highlight important updates into treatments for these two debilitating diseases.

Promising Probiotic for Liver Disease

A study published in Gastroenterology found that, over a six-month period, daily intake of the probiotic VSL#3® significantly improved liver function and reduced the risk of hospitalization in patients with cirrhosis. Patients who received the probiotic also had a reduction in the development of hepatic encephalopathy, the worsening of brain function that occurs when the liver is no longer able to remove toxic substances in the blood. There were no adverse events related to VSL#3.

The authors have no conflicts to disclose.

Drug Reduces Liver Fat Content in NAFLD Patients

Publishing in Clinical Gastroenterology and Hepatology, researchers report that three months' administration of the fatty acid/bile acid conjugate Aramchol is safe, tolerable and significantly reduces liver fat content in patients with NAFLD. The reduction in liver fat content occurred in a dose-dependent manner and was associated with a trend of metabolic improvements, indicating that Aramchol is a candidate for the treatment of fatty liver-related diseases, currently an unmet need.

This research was supported by Galmed Medical Research, Ltd.

Resveratrol Does Not Benefit Patients with NAFLD

Reporting in Clinical Gastroenterology and Hepatology, researchers find that eight weeks administration of resveratrol did not induce therapeutic benefits in men with established NAFLD, compared with placebo. Caution is warranted for use in obesity with chronic liver disease until further research determines safety.

This research was supported by the Princess Alexandra Research Foundation, the Lions Medical Research Foundation, and the National Health and Medical Research Council of Australia.


Story Source:

The above story is based on materials provided by American Gastroenterological Association. Note: Materials may be edited for content and length.


Journal References:

  1. Radha K. Dhiman, Baldev Rana, Swastik Agrawal, Ashish Garg, Madhu Chopra, Kiran K. Thumburu, Amit Khattri, Samir Malhotra, Ajay Duseja, Yogesh K. Chawla. Probiotic VSL#3 Reduces Liver Disease Severity and Hospitalization in Patients With Cirrhosis: A Randomized, Controlled Trial. Gastroenterology, 2014; 147 (6): 1327 DOI: 10.1053/j.gastro.2014.08.031
  2. Rifaat Safadi, Fred M. Konikoff, Mahmud Mahamid, Shira Zelber-Sagi, Maya Halpern, Tuvia Gilat, Ran Oren. The Fatty Acid–Bile Acid Conjugate Aramchol Reduces Liver Fat Content in Patients With Nonalcoholic Fatty Liver Disease. Clinical Gastroenterology and Hepatology, 2014; 12 (12): 2085 DOI: 10.1016/j.cgh.2014.04.038
  3. Rifaat Safadi, Fred M. Konikoff, Mahmud Mahamid, Shira Zelber-Sagi, Maya Halpern, Tuvia Gilat, Ran Oren. The Fatty Acid–Bile Acid Conjugate Aramchol Reduces Liver Fat Content in Patients With Nonalcoholic Fatty Liver Disease. Clinical Gastroenterology and Hepatology, 2014; 12 (12): 2085 DOI: 10.1016/j.cgh.2014.04.038

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Digoxin associated with higher risk of death, hospitalization, study shows

 


Digoxin, a drug commonly used to treat heart conditions, was associated with a 71 percent higher risk of death and a 63 percent higher risk of hospitalization among adults with diagnosed atrial fibrillation and no evidence of heart failure, according to a Kaiser Permanente study that appears in the current online issue of Circulation: Arrhythmia and Electrophysiology.

Digoxin is a drug derived from digitalis, which has been used for more than a century for heart-rate control in patients with atrial fibrillation, and it remains commonly used for this purpose worldwide. Current clinical practice guidelines for the management of atrial fibrillation recommend the use of digoxin alone for resting heart-rate control in sedentary individuals.

"Our findings suggest that the use of digoxin should be re-evaluated for the treatment of atrial fibrillation in contemporary clinical practice," said study co-author Anthony Steimle, MD, Chief of Cardiology at Kaiser Permanente Santa Clara Medical Center. "Given the other options available for heart-rate control, digoxin should be used with caution in the management of atrial fibrillation, especially in the absence of symptomatic systolic heart failure."

The results of this study follow on the findings by many of the same investigators in a 2013 study that revealed digoxin was associated with a 72 percent higher rate of death among adults with newly diagnosed systolic heart failure.

The current study was conducted between Jan. 1, 2006 and June 30, 2009 among almost 15,000 adults within Kaiser Permanente's Northern and Southern California regions who had recently diagnosed atrial fibrillation and no prior heart failure or digoxin use. Researchers examined the independent association between newly initiated digoxin use and the risks of death and hospitalization.

During the study period, 4,858 or 17.8 percent of the participants initiated digoxin use. There were 1,140 deaths among the study cohort, with a significantly higher rate of death in digoxin users compared with non-users (8.3 vs. 4.9 per 100 person years). At the same time, there were 8,456 hospitalizations for any cause, and the rate of hospitalization was higher for patients who received digoxin compared with those who did not (60.1 vs. 37.2 per 100 person years).

"Digoxin remains commonly used for rate control in atrial fibrillation, but very limited data exist to support this practice -- mostly small, older clinical studies with very limited follow-up that did not assess the long-term effects of digoxin on mortality or hospitalization," said Alan S. Go, MD, senior author of the study and research scientist at the Kaiser Permanente Division of Research in Oakland, California.

"In contrast, this study included the largest and most diverse sample of adults with incident atrial fibrillation not complicated by heart failure treated in clinical practice reported to date, with results that were consistent across age and gender," said Dr. Go. "We believe these findings, which build on earlier work, have significant value in guiding clinical cardiology decision-making in regard to digoxin use in the modern era."


Story Source:

The above story is based on materials provided by Kaiser Permanente. Note: Materials may be edited for content and length.


Journal Reference:

  1. J. V. Freeman, K. Reynolds, M. Fang, N. Udaltsova, A. Steimle, N. K. Pomernacki, L. H. Borowsky, T. N. Harrison, D. E. Singer, A. S. Go. Digoxin and Risk of Death in Adults with Atrial Fibrillation: The ATRIA-CVRN Study. Circulation: Arrhythmia and Electrophysiology, 2014; DOI: 10.1161/CIRCEP.114.002292