Implications of moderate altitude training for sea level endurance in elite distance runners

Elite distance runners participated in one of two studies designed to investigate the e ects of mod- erate altitude training (inspiratory partial pressure of oxygen »115±125 mmHg) on submaximal, maximal and supramaximal exercise performance following return to sea-level. Study 1 (New Mexico, USA) involved 14 subjects who were assigned to a 4-week altitude training camp (1500±2000 m) whilst 9 performance-matched subjects continued with an identical training programme at sea-level (CON). Ten EXP subjects who trained at 1640 m and 19 CON subjects also participated in study 2 (Krugersdorp, South Africa). Selected metabolic and cardiorespiratory parameters were determined with the subjects at rest and during exercise 21 days prior to (PRE) and 10 and 20 days following their return to sea- level (POST). Whole blood lactate decreased by 23% (P < 0.05 vs PRE) during submaximal exercise in the EXP group only after 20 days at sea-level (study 1). However, the lactate threshold and other measures of running economy remained unchanged. Similarly, su- pramaximal performance during a standardised track session did not change. Study 2 demonstrated that hypoxia per se did not alter performance. In contrast, in the EXP group supramaximal running velocity de- creased by 2% (P < 0.05) after 20 days at sea-level. Both studies were characterised by a 50% increase in the frequency of upper respiratory and gastrointestinal tract infections during the altitude sojourns, and two male subjects were diagnosed with infectious mononucleosis following their return to sea-level (study 1). Group mean plasma glutamine concentrations at rest decreased by 19% or 143 (74) lM (P < 0.001) after 3 weeks at alti- tude, which may have been implicated in the increased incidence of infectious illness

Social Stigma and Sexual Minorities’ Romantic Relationship Functioning: A Meta-Analytic Review

PublishedArticleThis is the author accepted manuscript. The final version is available from SAGE Publications via the DOI in this record.To bolster knowledge of determinants of relationship functioning among sexual minorities, the current meta-analysis aimed to quantitatively review evidence for the association between social stigma and relationship functioning as well as examine potential moderators. Thirty-five studies were identified, including 130 effect sizes (39 independent; N = 10,745). Across studies, evidence was found for a small but significant inverse association between social stigma and relationship functioning. Furthermore, this association was moderated by stigma type (with more deleterious associations for internalized relative to perceived stigma) and dimension of relationship functioning (with more deleterious associations for affective relative to cognitive and negative relative to positive). Evidence for demographic moderators (region, sex, race, age) was generally mixed although important limitations related to unique characteristics of study samples are discussed. We conclude by highlighting the importance of social stigma for relationship functioning and point toward directions for future research and policy action.The author(s) disclosed receipt of the following financial support for the research, authorship, and/or publication of this article: David Matthew Doyle is now a postdoctoral fellow in the Department of Epidemiology at Columbia University, supported by training grant, T32MH13043, from the National Institute of Mental Health

Exploring Time-Sensitive Variational Bayesian Inference LDA for Social Media Data

There is considerable interest among both researchers and the mass public in understanding the topics of discussion on social media as they occur over time. Scholars have thoroughly analysed sampling-based topic modelling approaches for various text corpora including social media; however, another LDA topic modelling implementation—Variational Bayesian (VB)—has not been well studied, despite its known efficiency and its adaptability to the volume and dynamics of social media data. In this paper, we examine the performance of the VB-based topic modelling approach for producing coherent topics, and further, we extend the VB approach by proposing a novel time-sensitive Variational Bayesian implementation, denoted as TVB. Our newly proposed TVB approach incorporates time so as to increase the quality of the generated topics. Using a Twitter dataset covering 8 events, our empirical results show that the coherence of the topics in our TVB model is improved by the integration of time. In particular, through a user study, we find that our TVB approach generates less mixed topics than state-of-the-art topic modelling approaches. Moreover, our proposed TVB approach can more accurately estimate topical trends, making it particularly suitable to assist end-users in tracking emerging topics on social media

PPM demodulation: On approaching fundamental limits of optical communications

We consider the problem of demodulating M-ary optical PPM (pulse-position modulation) waveforms, and propose a structured receiver whose mean probability of symbol error is smaller than all known receivers, and approaches the quantum limit. The receiver uses photodetection coupled with optimized phase-coherent optical feedback control and a phase-sensitive parametric amplifier. We present a general framework of optical receivers known as the conditional pulse nulling receiver, and present new results on ultimate limits and achievable regions of spectral versus photon efficiency tradeoffs for the single-spatial-mode pure-loss optical communication channel.Comment: 5 pages, 6 figures, IEEE ISIT, Austin, TX (2010

Testing demand responsive shared transport services via agent-based simulations

Demand Responsive Shared Transport DRST services take advantage of Information and Communication Technologies ICT, to provide on demand transport services booking in real time a ride on a shared vehicle. In this paper, an agent-based model ABM is presented to test different the feasibility of different service configurations in a real context. First results show the impact of route choice strategy on the system performance