Subtractive and divisive adaptation in visual motion computations

Models of visual motion processing that introduce priors for low speed through Bayesian computations are sometimes treated with scepticism by empirical researchers because of the convenient way in which parameters of the Bayesian priors have been chosen. Using the effects of motion adaptation on motion perception to illustrate, we show that the Bayesian prior, far from being convenient, may be estimated on-line and therefore represents a useful tool by which visual motion processes may be optimized in order to extract the motion signals commonly encountered in every day experience. The prescription for optimization, when combined with system constraints on the transmission of visual information, may lead to an exaggeration of perceptual bias through the process of adaptation. Our approach extends the Bayesian model of visual motion proposed byWeiss et al. [Weiss Y., Simoncelli, E., & Adelson, E. (2002). Motion illusions as optimal perception Nature Neuroscience, 5:598-604.], in suggesting that perceptual bias reflects a compromise taken by a rational system in the face of uncertain signals and system constraints. © 2007.

The end of transition?:The role of informal economies in the post-Soviet space

This book challenges the accepted notion that the transition from the command economy to market based systems is complete across the post-Soviet space. While it is noted that different political economies have developed in such states, such as Russia’s ‘managed democracy’, events such as Ukraine gaining ‘market economy status’ by the European Union and acceding to the World Trade Organisation in 2008 are taken as evidence that the reform period is over. Such thinking is based on numerous assumptions; specifically that economic transition has defined start and end points, that the formal economy now has primacy over other forms of economic practices and that national economic growth leads to the ‘trickle down’ of wealth to those marginalised by the transition process. Based on extensive ethnographic and quantitative research, conducted in Ukraine and Russia between 2004 - 2007, this book questions these assumptions by stating that the economies that operate across post-Soviet spaces are far from the textbook idea of a market economy. Through this the whole notion of ‘transition’ is problematised and the importance of informal economies to everyday life is demonstrated. Using case studies of various sectors, such as entrepreneurial behaviour and the higher education system, it is also shown how corruption has invaded almost all sectors of the post-Soviet every day.

Use of amino acids as counterions improves the solubility of the BCS II model drug, indomethacin

The number of new chemical entities (NCE) is increasing every day after the introduction of combinatorial chemistry and high throughput screening to the drug discovery cycle. One third of these new compounds have aqueous solubility less than 20µg/mL [1]. Therefore, a great deal of interest has been forwarded to the salt formation technique to overcome solubility limitations. This study aims to improve the drug solubility of a Biopharmaceutical Classification System class II (BCS II) model drug (Indomethacin; IND) using basic amino acids (L-arginine, L-lysine and L-histidine) as counterions. Three new salts were prepared using freeze drying method and characterised by FT-IR spectroscopy, proton nuclear magnetic resonance ((1)HNMR), Differential Scanning Calorimetry (DSC) and Thermogravimetric analysis (TGA). The effect of pH on IND solubility was also investigated using pH-solubility profile. Both arginine and lysine formed novel salts with IND, while histidine failed to dissociate the free acid and in turn no salt was formed. Arginine and lysine increased IND solubility by 10,000 and 2296 fold, respectively. An increase in dissolution rate was also observed for the novel salts. Since these new salts have improved IND solubility to that similar to BCS class I drugs, IND salts could be considered for possible waivers of bioequivalence.

Feature analysis of spammers in social networks with active honeypots:a case study of Chinese microblogging networks

In this poster we presented our preliminary work on the study of spammer detection and analysis with 50 active honeypot profiles implemented on Weibo.com and QQ.com microblogging networks. We picked out spammers from legitimate users by manually checking every captured user's microblogs content. We built a spammer dataset for each social network community using these spammer accounts and a legitimate user dataset as well. We analyzed several features of the two user classes and made a comparison on these features, which were found to be useful to distinguish spammers from legitimate users. The followings are several initial observations from our analysis on the features of spammers captured on Weibo.com and QQ.com. ¦The following/follower ratio of spammers is usually higher than legitimate users. They tend to follow a large amount of users in order to gain popularity but always have relatively few followers. ¦There exists a big gap between the average numbers of microblogs posted per day from these two classes. On Weibo.com, spammers post quite a lot microblogs every day, which is much more than legitimate users do; while on QQ.com spammers post far less microblogs than legitimate users. This is mainly due to the different strategies taken by spammers on these two platforms. ¦More spammers choose a cautious spam posting pattern. They mix spam microblogs with ordinary ones so that they can avoid the anti-spam mechanisms taken by the service providers. ¦Aggressive spammers are more likely to be detected so they tend to have a shorter life while cautious spammers can live much longer and have a deeper influence on the network. The latter kind of spammers may become the trend of social network spammer. © 2012 IEEE.

The dark side of the internet:protecting yourself and your family from online criminals

In less than a decade, personal computers have become part of our daily lives. Many of us come into contact with computers every day, whether at work, school or home. As useful as the new technologies are, they also have a darker side. By making computers part of our daily lives, we run the risk of allowing thieves, swindlers, and all kinds of deviants directly into our homes. Armed with a personal computer, a modem and just a little knowledge, a thief can easily access confidential information, such as details of bank accounts and credit cards. This book helps people avoid harm at the hands of Internet criminals. It offers a tour of the more dangerous parts of the Internet, as the author explains who the predators are, their motivations, how they operate and how to protect against them. In less than a decade, personal computers have become part of our daily lives. Many of us come into contact with computers every day, whether at work, school or home. As useful as the new technologies are, they also have a darker side. By making computers part of our daily lives, we run the risk of allowing thieves, swindlers, and all kinds of deviants directly into our homes. Armed with a personal computer, a modem and just a little knowledge, a thief can easily access confidential information, such as details of bank accounts and credit cards. This book is intended to help people avoid harm at the hands of Internet criminals. It offers a tour of the more dangerous parts of the Internet, as the author explains who the predators are, their motivations, how they operate and how to protect against them. Behind the doors of our own homes, we assume we are safe from predators, con artists, and other criminals wishing us harm. But the proliferation of personal computers and the growth of the Internet have invited these unsavory types right into our family rooms. With a little psychological knowledge a con man can start to manipulate us in different ways. A terrorist can recruit new members and raise money over the Internet. Identity thieves can gather personal information and exploit it for criminal purposes. Spammers can wreak havoc on businesses and individuals. Here, an expert helps readers recognize the signs of a would-be criminal in their midst. Focusing on the perpetrators, the author provides information about how they operate, why they do it, what they hope to do, and how to protect yourself from becoming a victim.