Changes in performance and poling kinetics during cross-country sprint skiing competition using the double-poling technique

In this study, changes in skiing performance and poling kinetics during a simulated cross-country sprint skiing competition were investigated. Twelve elite male cross-country skiers performed simulated sprint competition (4 × 1,150 m heat with 20 min recovery between the heats) using the double-poling technique. Vertical and horizontal pole forces and cycle characteristics were measured using a force plate system (20-m long) during the starting spurt, racing speed, and finishing spurt of each heat. Moreover, heat and 20-m phase velocities were determined. Vertical and horizontal pole impulses as well as mean cycle length were calculated. The velocities of heats decreased by 2.7 ± 1.7% (p = 0.003) over the simulated competition. The 20-m spurting velocity decreased by 16 ± 5% (p < 0.002) and poling time increased by 18 ± 9% (p < 0.003) in spurt phases within heats. Vertical and horizontal poling impulses did not change significantly during the simulation; however, the mean forces decreased (p < 0.039) (vertical by 24 ± 11% and horizontal by 20 ± 10%) within heats but not between the heats. Decreased heat velocities over the simulated sprint and spurting velocities within heats indicated fatigue among the skiers. Fatigue was also manifested by decreased pole force production and increased poling time.     

Simple Semantics in Topic Detection and Tracking

Topic Detection and Tracking (TDT) is a research initiative that aims at techniques to organize news documents in terms of news events. We propose a method that incorporates simple semantics into TDT by splitting the term space into groups of terms that have the meaning of the same type. Such a group can be associated with an external ontology. This ontology is used to determine the similarity of two terms in the given group. We extract proper names, locations, temporal expressions and normal terms into distinct sub-vectors of the document representation. Measuring the similarity of two documents is conducted by comparing a pair of their corresponding sub-vectors at a time. We use a simple perceptron to optimize the relative emphasis of each semantic class in the tracking and detection decisions. The results suggest that the spatial and the temporal similarity measures need to be improved. Especially the vagueness of spatial and temporal terms needs to be addressed.     

The Future of Radio Revisited: Expert Perspectives and Future Scenarios for Radio Media in 2025

In 2005–2006 the research group DRACE (Digital Radio Cultures in Europe) performed a study on how 43 people in key positions related to the radio industry in 4 European countries and Canada viewed the future of radio and which delivery technologies they considered would be most successful. In addition, it analyzed the motives and reasons certain technologies were seen as more promising than others. Finally, it presented 4 different future scenarios for radio media. The study was published in the Journal of Radio and Audio Media, May 2008.

In 2005 the future of radio was considered much less obvious and clear than it appeared 10 years previously. Instead of a transition from analog to digital audio broad- casting (DAB), there was a selection of alternative technological options for digital audio delivery. When looking back from 2015 and considering the results of expert interviews, the project group about Public Service Media in the HERA project: Transnational Radio Encounters found interesting perspectives in replicating this study—now looking forward to 2025. By using the same questionnaire and interviewing the same experts (or new persons in the same positions) they could compare the predictions with the present situation, looking for technological, regulatory, policy based, and user-oriented contexts. Furthermore, they could ask the experts to look 10 years forward to 2025. Besides from the interviews, desk studies were performed in order to explore the national similarities and differences as background for the analysis of the scenarios for the 2015 and 2025 studies.

This comparative study involves Denmark, Finland, Germany, Ireland, and the UK.     

Contralateral limb deficit after ACL-reconstruction: an analysis of early and late phase of rate of force development

The aim of this study was to assess the effect of a unilateral anterior cruciate ligament reconstruction (ACLR) on maximum voluntary contraction (MVC) and explosive strength of both the involved limb and the uninvolved limb. Nineteen male athletes completed a standard isometric testing protocol 4 months post-ACLR, while 16 healthy participants served as a control group (CG). The explosive strength of the knee extensors and flexors was assessed as RFD obtained from the slope of the force–time curves over various time intervals. Both muscle groups of the involved limb had significantly lower MVC compared to the uninvolved. The involved limb also had significantly lower RFD in the late phase of contraction (140–250 ms) for both knee extensors and flexors (P < 0.05). There was no difference in MVC between the uninvolved limb and the CG. However, RFD of the uninvolved limb was lower compared to CG for both knee extensors (0–180 ms; P < 0.01) and flexors (0–150 ms; P < 0.05). ACLR leads to lower MVC and explosive strength of the involved limb. As a consequence of potential crossover (presumably neural-mediated) effects, explosive strength deficits could be bilateral, particularly in the early phase of the contraction (<100 ms).     

Sleep of professional athletes: Underexploited potential to improve health and performance

Sleep disorders have become increasingly prevalent affecting health and working ability. Restorative sleep may be considered important for athletes’ successful recovery and performance. However, some athletes seem to experience major problems in sleeping. Thus far, there is limited scientific information about their sleep. This study aimed to evaluate the quality of sleep and the prevalence of sleep disorders as well as the impact of a structured sleep counselling protocol in professional athletes. A total of 107 professional ice hockey players participated in the study. The exploratory observational 1-year follow-up study consisted of questionnaire-based sleep assessment followed by general sleep counselling and, when needed, polysomnography and an individual treatment plan. One in every four players was found to have a significant problem in sleeping. All athletes considered sleep essential for their health and three in every four players considered that counselling would improve their performance. Counselling and individual treatment were found to improve significantly the quality of sleep with the mean alteration of 0.6 (95% CI 0.2–1.0, P = 0.004) in a scale from 0 to 10. Our results support that sleep problems are common in professional athletes. However, systematic examination, counselling and individual treatment planning can improve the quality of their sleep.     

Comparison of diagnostic accuracy for eight SARS-CoV-2 serological assays

IntroductionSevere acute respiratory syndrome coronavirus 2 (SARS-CoV-2) serological tests have been suggested as an additional diagnostic tool in highly suspected cases with a negative molecular test and determination of seroprevalence in population. We compared the diagnostic performance of eight commercial serological assays for IgA, IgM, and IgG antibodies to the SARS-CoV-2 virus.Materials and methodsThe comparison study was performed on a total of 76 serum samples: 30 SARS-CoV-2 polymerase chain reaction (PCR)-negative and 46 SARS-CoV-2 PCR-positive patients with asymptomatic to severe disease and symptoms duration from 3-30 days. The study included: three rapid lateral flow immunochromatographic assays (LFIC), two enzyme-linked immunosorbent assays (ELISA), and three chemiluminescence immunoassays (CLIA).ResultsAgreement between IgM assays were minimal to moderate (kappa 0.26 to 0.63) and for IgG moderate to excellent (kappa 0.72 to 0.92). Sensitivities improved with > 10 days of symptoms and were: 30% to 89% for IgM; 89% to 100% for IgG; 96% for IgA; 100% for IgA/IgM combination; 96% for total antibodies. Overall specificities were: 90% to 100% for IgM; 85% to 100% for IgG; 90% for IgA; 70% for IgA/IgM combination; 100% for total antibodies. Diagnostic accuracy for IgG ELISA and CIA assays were excellent (AUC ≥ 0.90), without significant difference. IgA showed significantly better diagnostic accuracy than IgM (P < 0.001).ConclusionThere is high variability between IgM assays independently of the assay format, while IgG assays showed moderate to perfect agreement. The appropriate time for testing is crucial for the proper immunity investigation.     

Predicting elections from social media: a three-country,three-method comparative study

ABSTRACT

This study introduces and evaluates the robustness of different volumetric, sentiment, and social network approaches to predict the elections in three Asian countries – Malaysia, India, and Pakistan from Twitter posts. We find that predictive power of social media performs well for India and Pakistan but is not effective for Malaysia. Overall, we find that it is useful to consider the recency of Twitter posts while using it to predict a real outcome, such as an election result. Sentiment information mined using machine learning models was the most accurate predictor of election outcomes. Social network information is stable despite sudden surges in political discussions, for e.g. around elections-related news events. Methods combining sentiment and volume information, or sentiment and social network information, are effective at predicting smaller vote shares, for e.g. vote shares in the case of independent candidates and regional parties. We conclude with a detailed discussion on the caveats of social media analysis for predicting real-world outcomes and recommendations for future work.     

The round-wheel compound bow model revisited: a new extension

An extended offset-eccentric model of an archery twin-round-wheel compound bow is derived. Varying some parameters of the model, the respective effects on the calculated force–draw curve are considered. Two static quality coefficients for the compound bow are introduced. It was found that the twin-round-wheel compound bow can be designed to be more energetic with the help of the model. For a bow with some modifications 18.5% increment of energy was calculated. Also a theoretical limit for the force–draw curve of the compound bow is concluded.     

On the relationship between the structural and socioacademic communities of a coauthorship network

This article presents a study that compares detected structural communities in a coauthorship network to the socioacademic characteristics of the scholars that compose the network. The coauthorship network was created from the bibliographic record of a multi-institution, interdisciplinary research group focused on the study of sensor networks and wireless communication. Four different community detection algorithms were employed to assign a structural community to each scholar in the network: leading eigenvector, walktrap, edge betweenness and spinglass. Socioacademic characteristics were gathered from the scholars and include such information as their academic department, academic affiliation, country of origin, and academic position. A Pearson’s χ²test, with a simulated Monte Carlo, revealed that structural communities best represent groupings of individuals working in the same academic department and at the same institution. A generalization of this result suggests that, even in interdisciplinary, multi-institutional research groups, coauthorship is primarily driven by departmental and institutional affiliation.     

Context-related problems and university students’ dropout intentions—the buffering effect of personal best goals

This study investigates the effects of contextual and motivational factors as well as, crucially, their interaction in predicting university students’ dropout intentions. We focus on context-related problems in students’ degree program as contextual factors and students’ personal best goals (PB goals) as motivational factors. The sample of this study comprised 432 university students (74.3% female) enrolled in master’s degree programs at Austrian universities. Data was analyzed by means of structural equation modeling and latent moderated structural equation modeling. The results indicated that PB goals were negatively associated with dropout intentions, while context-related problems were positively associated with dropout intentions. In addition, the context-related problems × PB goals interaction effect proved significant and negatively predicted dropout intentions. By showing that the positive relation between context-related problems and dropout intentions can be reversed by increasing PB goals, we provide empirical evidence of the buffering effect of PB goals in the face of context-related problems.