Corrections to Einstein's relation for Brownian motion in a tilted periodic potential

In this paper we revisit the problem of Brownian motion in a tilted periodic potential. We use homogenization theory to derive general formulas for the effective velocity and the effective diffusion tensor that are valid for arbitrary tilts. Furthermore, we obtain power series expansions for the velocity and the diffusion coefficient as functions of the external forcing. Thus, we provide systematic corrections to Einstein's formula and to linear response theory. Our theoretical results are supported by extensive numerical simulations. For our numerical experiments we use a novel spectral numerical method that leads to a very efficient and accurate calculation of the effective velocity and the effective diffusion tensor.Comment: 29 pages, 7 figures, submitted to the Journal of Statistical Physic

Large expert-curated database for benchmarking document similarity detection in biomedical literature search

Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

The changing society of Hong Kong in the post-war period and its implications for moral education

SIGLEAvailable from British Library Document Supply Centre- DSC:DX186950 / BLDSC - British Library Document Supply CentreGBUnited Kingdo

Experimental investigations on the cooling of a motorcycle helmet with phase change material (PCM)

The thermal comfort of motorcycle helmet during hot weather is important as it can affect the physiological and psychological condition of the rider. This paper examines the use of phase change material (PCM) to cool a motorcycle helmet and presents the experimental investigations on the influences of the simulated solar radiation, wind speed, and heat generation rate on the cooling system. The result shows that the PCM-cooled helmet is able to prolong the thermal comfort period compared to a normal helmet. The findings also indicate that the heat generation from the head is the predominant factor that will affect the PCM melting time. Simulated solar radiation and ram-air due to vehicle motion under adiabatic condition can have very little influences on the PCM melting time. The results suggested that the helmet usage time would be influenced by the amount of heat generated from the head. Some major design considerations based on these findings have been included. Although this investigation focuses on the cooling of a motorcyclist helmet, the findings would also be useful for the development of PCM-cooling systems in other applications

Intelligent system design: supervising cognitive tele-rehabilitation with a virtual therapist

Intelligent virtual rehabilitation is feasible. The basis for the development of the virtual therapist has been established but the system needs refinement, improvement and more clinical trials

Intelligent system design: supervising cognitive tele-rehabilitation with a virtual therapist

Intelligent virtual rehabilitation is feasible. The basis for the development of the virtual therapist has been established but the system needs refinement, improvement and more clinical trials

Micromechanics of perforation penetration and sand production in weak sandstone formations in Kazakhstan

Research on sand production has been conducted using different approaches: analytical, laboratory experiments including centrifuge tests, continuum based modeling and a more recent trend using discrete modeling

A man with osteoblastic metastasis and hypocalcaemia

Singapore Medical Journal41274-76SIMJ