A Brownian particle in a microscopic periodic potential

We study a model for a massive test particle in a microscopic periodic potential and interacting with a reservoir of light particles. In the regime considered, the fluctuations in the test particle's momentum resulting from collisions typically outweigh the shifts in momentum generated by the periodic force, and so the force is effectively a perturbative contribution. The mathematical starting point is an idealized reduced dynamics for the test particle given by a linear Boltzmann equation. In the limit that the mass ratio of a single reservoir particle to the test particle tends to zero, we show that there is convergence to the Ornstein-Uhlenbeck process under the standard normalizations for the test particle variables. Our analysis is primarily directed towards bounding the perturbative effect of the periodic potential on the particle's momentum.Comment: 60 pages. We reorganized the article and made a few simplifications of the conten

A preliminary audit of medical and aid provision in English Rugby union clubs:compliance with Regulation 9

BackgroundGoverning bodies are largely responsible for the monitoring and management of risks associated with a safe playing environment, yet adherence to regulations is currently unknown. The aim of this study was to investigate and evaluate the current status of medical personnel, facilities, and equipment in Rugby Union clubs at regional level in England.MethodsA nationwide cross-sectional survey of 242 registered clubs was undertaken, where clubs were surveyed online on their current medical personnel, facilities, and equipment provision, according to regulation 9 of the Rugby Football Union (RFU).ResultsOverall, 91 (45. 04%) surveys were returned from the successfully contacted recipients. Of the completed responses, only 23.61% (n = 17) were found to be compliant with regulations. Furthermore, 30.56% (n = 22) of clubs were unsure if their medical personnel had required qualifications; thus, compliance could not be determined. There was a significant correlation (p = −0.029, r = 0.295) between club level and numbers of practitioners. There was no significant correlation indicated between the number of practitioners/number of teams and number of practitioners/number of players. There were significant correlations found between club level and equipment score (p = 0.003, r = −0.410), club level and automated external defibrillator (AED) access (p = 0.002, r = −0.352) and practitioner level and AED access (p = 0.0001, r = 0.404). Follow-up, thematic analysis highlighted widespread club concern around funding/cost, awareness, availability of practitioners and AED training.ConclusionThe proportion of clubs not adhering overall compliance with Regulation 9 of the RFU is concerning for player welfare, and an overhaul, nationally, is required

Synovial cell metabolism and chronic inflammation in rheumatoid arthritis

Metabolomic studies of body fluids show that immune-mediated inflammatory diseases such as rheumatoid arthritis (RA) are associated with metabolic disruption. This is likely to reflect the increased bioenergetic and biosynthetic demands of sustained inflammation and changes to nutrient and oxygen availability in damaged tissue. The synovial membrane lining layer is the principle site of inflammation in RA. Here the resident cells are the fibroblast-like synoviocytes (FLS) and the synovial tissue macrophages (STM), which are transformed toward overproduction of enzymes which degrade cartilage and bone, and cytokines which promote immune cell infiltration. Recent studies have shown metabolic changes in both FLS and macrophages from RA patients and these may be therapeutically targetable. However, as the origins and subset specific functions of synoviocytes are poorly understood and the signaling modules which control metabolic deviation in RA synovial cells are yet to be explored, significant additional research is needed to translate these findings toward clinical application. Furthermore, in many inflamed tissues, different cell types can forge metabolic collaborations through solute carriers (SLC) in their membranes, to meet a high demand for energy or biomolecules. Such relationships are likely to exist in the synovium and are yet to be explored. Finally, it is not yet known whether metabolic change is a consequence of disease or if primary changes to cellular metabolism might underlie or contribute to early stage disease pathogenesis. This article collates what is known about metabolism in synovial tissue cells and highlights future research directions in this area

At Least Bias Is Bipartisan: A Meta-Analytic Comparison of Partisan Bias in Liberals and Conservatives

Both liberals and conservatives accuse their political opponents of partisan bias, but is there empirical evidence that one side of the political aisle is indeed more biased than the other? To address this question, we meta-analyzed the results of 51 experimental studies, involving over 18,000 participants, that examined one form of partisan bias—the tendency to evaluate otherwise identical information more favorably when it supports one’s political beliefs or allegiances than when it challenges those beliefs or allegiances. Two hypotheses based on previous literature were tested: an asymmetry hypothesis (predicting greater partisan bias in conservatives than in liberals) and a symmetry hypothesis (predicting equal levels of partisan bias in liberals and conservatives). Mean overall partisan bias was robust (r = .245), and there was strong support for the symmetry hypothesis: Liberals (r = .235) and conservatives (r = .255) showed no difference in mean levels of bias across studies. Moderator analyses reveal this pattern to be consistent across a number of different methodological variations and political topics. Implications of the current findings for the ongoing ideological symmetry debate and the role of partisan bias in scientific discourse and political conflict are discussed

Endoscopic ultrasound in the assessment of advanced duodenal adenomatosis in familial adenomatous polyposis

Objective Current surveillance strategies for duodenal adenomatosis in familial adenomatous polyposis (FAP) miss malignancies and underestimate cancer risk in ampullary disease. This study aimed to evaluate the utility of endoscopic ultrasound (EUS) in the assessment of FAP patients with duodenal and/or ampullary polyposis referred for surgical intervention. Design A retrospective analysis of FAP patients undergoing index EUS between December 2006 and May 2015 was performed. Follow-up was completed in January 2018, including review of all EUS procedures and surgical interventions (median follow-up 6 years). Results Fifty-five patients underwent 188 EUS procedures. Six patients (11%) developed malignancy (three duodenal, three ampullary). Ampullary cancer risk was underestimated by Spigelman stage and overestimated by Kashiwagi classification. Ultrasound findings were poor predictors of malignancy, with common bile duct dilatation being the only finding present in one EUS prior to a diagnosis of ampullary cancer. The best predictors of ampullary malignancy were an ampullary polyp size >3 cm and an increase >1 cm in ampullary polyp size. Ampullary polyp size >3 cm provided the best predictive value, correctly identifying two of the three cases of ampullary cancer and both patients with high-grade dysplasia. EUS biopsy failed to detect malignancy later confirmed by surgical histology in two patients. Conclusion EUS surveillance confers little additional benefit to standard endoscopic surveillance in FAP patients. The best predictor of ampullary malignancy is an ampullary polyp >3 cm; this could be regarded as a relative indication for surgery

Endoscopic ultrasound in the assessment of advanced duodenal adenomatosis in familial adenomatous polyposis

Objective: Current surveillance strategies for duodenal adenomatosis in familial adenomatous polyposis (FAP) miss malignancies and underestimate cancer risk in ampullary disease. This study aimed to evaluate the utility of endoscopic ultrasound (EUS) in the assessment of FAP patients with duodenal and/or ampullary polyposis referred for surgical intervention. Design: A retrospective analysis of FAP patients undergoing index EUS between December 2006 and May 2015 was performed. Follow-up was completed in January 2018, including review of all EUS procedures and surgical interventions (median follow-up 6 years). Results: Fifty-five patients underwent 188 EUS procedures. Six patients (11%) developed malignancy (three duodenal, three ampullary). Ampullary cancer risk was underestimated by Spigelman stage and overestimated by Kashiwagi classification. Ultrasound findings were poor predictors of malignancy, with common bile duct dilatation being the only finding present in one EUS prior to a diagnosis of ampullary cancer. The best predictors of ampullary malignancy were an ampullary polyp size >3 cm and an increase >1 cm in ampullary polyp size. Ampullary polyp size >3 cm provided the best predictive value, correctly identifying two of the three cases of ampullary cancer and both patients with high-grade dysplasia. EUS biopsy failed to detect malignancy later confirmed by surgical histology in two patients. Conclusion: EUS surveillance confers little additional benefit to standard endoscopic surveillance in FAP patients. The best predictor of ampullary malignancy is an ampullary polyp >3 cm; this could be regarded as a relative indication for surgery

A pulse compression radar system for high-resolution ionospheric sounding

A low frequency pulse compression radar system, capable of 0.75 km spatial resolution, has been developed. This system utilizes a linear frequency-modulated signal, and yields an effective peak power enhancement of 14.5 dB, over a conventional radar of equivalent resolution. The required instrumentation, as well as the development of the necessary signal processing software, are described in detail. It is shown that the resolution and peak power enhancement achieved by the system are consistent with those predicted by theory. The effectiveness of the pulse compression radar as a tool for ionospheric observation is demonstrated by comparing its performance to that of a conventional radar operating simultaneously

Does the biomarker search paradigm need re-booting?

The clinical problem of bladder cancer is its high recurrence and progression, and that the most sensitive and specific means of monitoring is cystoscopy, which is invasive and has poor patient compliance. Biomarkers for recurrence and progression could make a great contribution, but in spite of decades of research, no biomarkers are commercially available with the requisite sensitivity and specificity. In the post-genomic age, the means to search the entire genome for biomarkers has become available, but the conventional approaches to biomarker discovery are entirely inadequate to yield results with the new technology. Finding clinically useful biomarker panels with sensitivity and specificity equal to that of cystoscopy is a problem of systems biology