Formalising progress properties of non-blocking programs

A non-blocking program is one that uses non-blocking primitives, such as load-linked/store-conditional and compare-and-swap, for synchronisation instead of locks so that no process is ever blocked. According to their progress properties, non-blocking programs may be classified as wait-free, lock-free or obstruction-free. However, a precise description of these properties does not exist and it is not unusual to find a definition that is ambiguous or even incorrect. We present a formal definition of the progress properties so that any confusion is removed. The formalisation also allows one to prove the widely believed presumption that wait-freedom is a special case of lock-freedom, which in turn is a special case of obstruction-freedom.

Implicit learning is not subject to blocking

Explicit (aware) learning has been shown to evidence certain characteristics, such as extinction, blocking, occasion setting, and reliance on context. These characteristics have not been assessed in implicit (unaware) learning. The current study investigated whether implicit learning is subject to blocking. Participants completed a cued reaction time task, where they watched rapid presentations of a random sequence of 8 pairs of shapes, and responded to two target shapes. One target was always preceded by a cue. The experimental group completed a pretraining phase where half the cue, one shape, was followed by the target. Both experimental and control groups completed a training phase where both elements of the cue, two shapes, were followed by the target. Both aware and unaware participants evidenced learning, whereby responding was faster for cued than uncued targets. Aware participants in the experimental group responded faster to targets preceded by the pretrained element than by the other element of the cue. Control and unaware experimental participants were faster to respond to targets preceded by either element of the cue. As blocking was only evident in aware participants, but implicit learning was observed in all participants, it is concluded that implicit learning is not subject to blocking.

Conical refraction healing after partially blocking the input beam

In conical refraction, when a focused Gaussian beam passes along one of the optic axes of a biaxial crystal, it is transformed into a pair of concentric bright rings at the focal plane. We demonstrate both theoretically and experimentally that this transformation is hardly affected by partially blocking the Gaussian input beam with an obstacle. We analyze the influence of the size of the obstruction both on the transverse intensity pattern of the beam and on its state of polarization, which is shown to be very robust.

On Blocking Sets in Affine Hjelmslev Planes

ACM Computing Classification System (1998): G.2.1.

Vagal blocking for obesity control : a possible mechanism-of-action

Peer reviewed

Planned parenthood employees outside their office where anti-choice group is blocking entrance office

General note: Title and date provided by Bettye Lane.

Planned parenthood employees versus anti-choice groups who are blocking the planned parenthood entrance

General note: Title and date provided by Bettye Lane.

Anti-war, Anti-Vietnam protesters sitting in Times Square, blocking traffic

General note: Title and date provided by Bettye Lane.

REASONS BEHIND THE USAGE OF ONLINE AD BLOCKING TOOLS

Online advertising has been growing rapidly since the mid-90s. In recent years, online advertising has become as relevant as an advertising medium as print and television are. However, despite the growth, the generally held consensus is that consumers are not interested in online advertisements. The arrival of online ad blocking tools has offered consumers a very effective way to avoid and block online advertisements. Although these tools have now been around for several years and the most popular software’s have hundreds of millions of active users, the phenomenon of ad blocking has gathered surprisingly little attention from academic marketing research. For this reason, ad blocking was chosen as the topic of this thesis study. The researcher was particularly interested in the reasons behind the usage of online ad blocking tools. The object of the empirical part of this study is to provide new and valid information regarding the reasons behind the usage of online ad blocking tools. The empirical research of this study consisted of a survey study that mixed both quantitative and qualitative elements. Although the sample size of the study was fairly limited, the study provided useful answers to individual research questions and provided new knowledge regarding the reasons behind the usage of online ad blocking and the phenomenon of ad blocking as a whole. The study provides further evidence that consumers are aware of online ad blocking tools and a significant portion of them are interested in using them. This study indicates that many of the consumers who do not have previous knowledge of these tools would actually be interested in them. The reason for the usage of online ad blocking tools varies from institutional reasons to instrumental reason, such as poor quality of the online advertisements. However, there were participants who were not interested in the usage of online ad blocking tools, and some of them reported to find online advertising useful. There also seems to be a concern among some consumers that online ad blocking will have a negative effect on online content in the future if the ad blocking will keep growing as a phenomenon. This certainly can be the case, and it is very interesting to see how the development of online ad blocking will shape the online advertising, how the advertising industry will respond to the growth of online ad blocking and how will the consumers respond to these changes.

A cluster-randomised intervention trial against Schistosoma japonicum in the Peoples' Republic of China: bovine and human transmission

Background Zoonotic schistosomiasis japonica is a major public health problem in China. Bovines, particularly water buffaloes, are thought to play a major role in the transmission of schistosomiasis to humans in China. Preliminary results (1998–2003) of a praziquantel (PZQ)-based pilot intervention study we undertook provided proof of principle that water buffaloes are major reservoir hosts for S. japonicum in the Poyang Lake region, Jiangxi Province. Methods and Findings Here we present the results of a cluster-randomised intervention trial (2004–2007) undertaken in Hunan and Jiangxi Provinces, with increased power and more general applicability to the lake and marshlands regions of southern China. The trial involved four matched pairs of villages with one village within each pair randomly selected as a control (human PZQ treatment only), leaving the other as the intervention (human and bovine PZQ treatment). A sentinel cohort of people to be monitored for new infections for the duration of the study was selected from each village. Results showed that combined human and bovine chemotherapy with PZQ had a greater effect on human incidence than human PZQ treatment alone. Conclusions The results from this study, supported by previous experimental evidence, confirms that bovines are the major reservoir host of human schistosomiasis in the lake and marshland regions of southern China, and reinforce the rationale for the development and deployment of a transmission blocking anti-S. japonicum vaccine targeting bovines.