Factors Influencing Physical and Technical Variability in the English Premier League

Purpose: To investigate match-to-match variability of physical and technical performances in English Premier League players and quantify the influence of positional and contextual factors. Methods: Match data (N = 451) were collected using a multicamera computerized tracking system across multiple seasons (2005–06 to 2012–13). The coefficient of variation (CV) was calculated from match to match for physical and technical performances in selected positions across different match contexts (location, standard, and result). Results: Wide midfielders demonstrated the greatest CVs for total distance (4.9% ± 5.9%) and central midfielders the smallest (3.6% �} 2.0%); nevertheless, all positions exhibited CVs .05, effect size [ES] 0.1–0.3). Central defenders demonstrated the greatest CVs and wide midfielders the lowest for both high-intensity running (20.2% ± 8.8% and 13.7% ± 7.7%, P < .05, ES 0.4–0.8) and sprint distance (32.3% ± 13.8% and 22.6% ± 11.2%, P < .05, ES 0.5–0.8). Technical indicators such as tackles (83.7% ± 42.3%), possessions won (47.2% ± 27.9%), and interceptions (59.1% ± 37.3%) illustrated substantial variability for attackers compared with all other positions (P < .05, ES 0.4–1.1). Central defenders demonstrated large variability for the number of times tackled per match (144.9% ± 58.3%) and passes attempted and received compared with other positions (39.2% ± 17.5% and 46.9% ± 20.2%, P < .001, ES 0.6–1.8). Contextual factors had limited impact on the variability of physical and technical parameters. Conclusions: The data demonstrate that technical parameters varied more from match to match than physical parameters. Defensive players (fullbacks and central defenders) displayed higher CVs for offensive technical variables, while attacking players (attackers and wide midfielders) exhibited higher CVs for defensive technical variables. Physical and technical performances are variable per se regardless of context

Magnetospheric and solar wind dependences of coupled fast-mode resonances outside the plasmasphere

We investigate the magnetospheric and solar wind factors that control the occurrence probabilities, locations, and frequencies of standing Alfvén waves excited via coupled fast-mode resonances (cFMRs) in the outer magnetosphere's dawn and dusk sectors. The variation of these cFMR properties with the observed magnetospheric plasma density profiles and inputs to the semiempirically modeled magnetic field from the numerical cFMR calculations of Archer et al. (2015) are studied. The probability of cFMR occurrence increases with distance between the magnetopause and the Alfvén speed's local maximum. The latter's location depends on magnetospheric activity: during high activity it is situated slightly outside the plasmapause, whereas at low activity it is found at much larger radial distances. The frequencies of cFMR are proportional to the Alfvén speed near the magnetopause, which is affected by both density and magnetic field variations. The location of the excited resonance, however, depends on the relative steepness of the Alfvén speed radial profile. The steeper this is, the closer the resonance is to the outer boundary and vice versa. The variation of the density profiles with solar wind conditions and activity is also shown

The Drosophila simulans Y chromosome interacts with the autosomes to influence male fitness.

This is the author's accepted manuscriptThe final version is available from Wiley via the DOI in this recordThe Y chromosome should degenerate because it cannot recombine. However, male limited transmission increases selection efficiency for male benefit alleles on the Y, and therefore Y-chromosomes should contribute significantly to variation in male-fitness. This means that although the Drosophila Y chromosome is small and gene-poor, Y-linked genes are vital for male fertility in D. melanogaster and the Y chromosome has large male-fitness effects. It is unclear if the same pattern is seen in the closely related D. simulans. We backcrossed Y chromosomes from 3 geographic locations into 5 genetic backgrounds and found strong Y and genetic background effects on male fertility. There was a significant Y-background interaction, indicating substantial epistasis between the Y and autosomal genes affecting male fertility. This supports accumulating evidence that interactions between the Y chromosome and the autosomes are key determinants of male fitness. This article is protected by copyright. All rights reserved.DJH was funded by The Leverhulme Trust

Frequency variability of standing Alfven waves excited by fast mode resonances in the outer magnetosphere

NASA. Grant Number: NAS5-0209

Polyandry and fitness in female horned flour beetles, Gnatocerus cornutus

This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Although polyandry is common, it is often unclear why females mate with multiple males, because although polyandry may provide females with direct or indirect fitness benefits, it can also be costly. Our understanding of polyandry is also restricted by the relative paucity of studies that disentangle the fitness effects of mating more than once with a single male and mating with multiple males. Here we investigated potential benefits and costs of polyandry in the horned beetle, Gnatocerus cornutus, while controlling for the number of matings. We found that female life span was independent of mating frequency, indicating that mating itself is not very costly. However, females that mated more than once laid more eggs and had greater lifetime reproductive success than singly mated females. Because the magnitude of these effects was similar in monandrous and polyandrous females, this improved fertility was due to multiple mating itself, rather than mating with multiple males. However, although polyandrous females produced more attractive sons, these males tended to have smaller mandibles and so may fare less well in male-male competition. The se results indicate that polyandry is relatively cost free, at least in the laboratory, and has direct and indirect benefits to female fitness. However, because the attractive sons produced by polyandrous females may fight less well, the indirect benefits of polyandry will depend on the intensity of male-male competition and how free females are to exert mate choice. Where competition between males is intense, polyandry benefits via son attractiveness may be reduced and perhaps even carry costs to female fitness.This study was supported by a Grant-in-Aid for Scientific Research (KAKENHI 25840157) from Japanese Ministry of Education, Science, Sports and Culture. We thank the Editor and referees for helpful comments which greatly improved the manuscript

Wolbachia infection can bias estimates of intralocus sexual conflict

This is the final version. Available from Wiley via the DOI in this record.Males and females share most of their genome and develop many of the same traits. However, each sex frequently has different optimal values for these shared traits, creating intralocus sexual conflict. This conflict has been observed in wild and laboratory populations of insects and affects important evolutionary processes such as sexual selection, the maintenance of genetic variation, and possibly even speciation. Given the broad impacts of intralocus conflict, accurately detecting and measuring it is important. A common way to detect intralocus sexual conflict is to calculate the intersexual genetic correlation for fitness, with negative values suggesting conflict. Here, we highlight a potential confounder of this measure—cytoplasmic incompatibility caused by the intracellular parasite Wolbachia. Infection with Wolbachia can generate negative intersexual genetic correlations for fitness in insects, suggestive of intralocus sexual conflict. This is because cytoplasmic incompatibility reduces the fitness of uninfected females mated to infected males, while uninfected males will not suffer reductions in fitness if they mate with infected females and may even be fitter than infected males. This can lead to strong negative intersexual genetic correlations for fitness, mimicking intralocus conflict. We illustrate this issue using simulations and then present Drosophila simulans data that show how reproductive incompatibilities caused by Wolbachia infection can generate signals of intralocus sexual conflict. Given that Wolbachia infection in insect populations is pervasive, but populations usually contain both infected and uninfected individuals providing scope for cytoplasmic incompatibility, this is an important consideration for sexual conflict research but one which, to date, has been largely underappreciated.Royal SocietyLeverhulme TrustNatural Environment Research CouncilNarodowe Centrum Nauk

Bats that walk: a new evolutionary hypothesis for the terrestrial behaviour of New Zealand's endemic mystacinids.

RIGHTS : This article is licensed under the BioMed Central licence at http://www.biomedcentral.com/about/license which is similar to the 'Creative Commons Attribution Licence'. In brief you may : copy, distribute, and display the work; make derivative works; or make commercial use of the work - under the following conditions: the original author must be given credit; for any reuse or distribution, it must be made clear to others what the license terms of this work are.BACKGROUND: New Zealand's lesser short-tailed bat Mystacina tuberculata is one of only two of c.1100 extant bat species to use a true walking gait when manoeuvring on the ground (the other being the American common vampire bat Desmodus rotundus). Mystacina tuberculata is also the last surviving member of Mystacinidae, the only mammalian family endemic to New Zealand (NZ) and a member of the Gondwanan bat superfamily Noctilionoidea. The capacity for true quadrupedal terrestrial locomotion in Mystacina is a secondarily derived condition, reflected in numerous skeletal and muscular specializations absent in other extant bats. The lack of ground-based predatory native NZ mammals has been assumed to have facilitated the evolution of terrestrial locomotion and the unique burrowing behaviour of Mystacina, just as flightlessness has arisen independently many times in island birds. New postcranial remains of an early Miocene mystacinid from continental Australia, Icarops aenae, offer an opportunity to test this hypothesis. RESULTS: Several distinctive derived features of the distal humerus are shared by the extant Mystacina tuberculata and the early Miocene Australian mystacinid Icarops aenae. Study of the myology of M. tuberculata indicates that these features are functionally correlated with terrestrial locomotion in this bat. Their presence in I. aenae suggests that this extinct mystacinid was also adapted for terrestrial locomotion, despite the existence of numerous ground-based mammalian predators in Australia during the early Miocene. Thus, it appears that mystacinids were already terrestrially-adapted prior to their isolation in NZ. In combination with recent molecular divergence dates, the new postcranial material of I. aenae constrains the timing of the evolution of terrestrial locomotion in mystacinids to between 51 and 26 million years ago (Ma). CONCLUSION: Contrary to existing hypotheses, our data suggest that bats are not overwhelmingly absent from the ground because of competition from, or predation by, other mammals. Rather, selective advantage appears to be the primary evolutionary driving force behind habitual terrestriality in the rare bats that walk. Unlike for birds, there is currently no evidence that any bat has evolved a reduced capacity for flight as a result of isolation on islands

Virtual Support for Bereaved Parents: Acceptability, Feasibility, and Preliminary Efficacy of HOPE Group

Background Bereaved parents demonstrate increased risk for long-term psychological problems and poorer overall quality of life. Bereavement support programs can promote improved coping and are positively received by parents but remain underutilized. Virtual programs may help address barriers to accessing bereavement resources, such as families’ physical distance to the hospital and trauma reactions when exposed to a setting where the child received care. The objective of this quality improvement study is to examine caregivers’ bereavement experiences and perspectives on HOPE Group, a virtual group program for bereaved caregivers administered by the palliative care team at Nemours Children\u27s Hospital, Delaware

Direct observations of a surface eigenmode of the dayside magnetopause

The abrupt boundary between a magnetosphere and the surrounding plasma, the magnetopause, has long been known to support surface waves. It was proposed that impulses acting on the boundary might lead to a trapping of these waves on the dayside by the ionosphere, resulting in a standing wave or eigenmode of the magnetopause surface. No direct observational evidence of this has been found to date and searches for indirect evidence have proved inconclusive, leading to speculation that this mechanism might not occur. By using fortuitous multipoint spacecraft observations during a rare isolated fast plasma jet impinging on the boundary, here we show that the resulting magnetopause motion and magnetospheric ultra-low frequency waves at well-defined frequencies are in agreement with and can only be explained by the magnetopause surface eigenmode. We therefore show through direct observations that this mechanism, which should impact upon the magnetospheric system globally, does in fact occur

The Middle to Later Stone Age transition at Panga ya Saidi, in the tropical coastal forest of eastern Africa

The Middle to Later Stone Age transition is a critical period of human behavioral change that has been variously argued to pertain to the emergence of modern cognition, substantial population growth, and major dispersals of Homo sapiens within and beyond Africa. However, there is little consensus about when the transition occurred, the geographic patterning of its emergence, or even how it is manifested in the stone tool technology that is used to define it. Here, we examine a long sequence of lithic technological change at the cave site of Panga ya Saidi, Kenya, that spans the Middle and Later Stone Age and includes human occupations in each of the last five Marine Isotope Stages. In addition to the stone artifact technology, Panga ya Saidi preserves osseous and shell artifacts, enabling broader considerations of the covariation between different spheres of material culture. Several environmental proxies contextualize the artifactual record of human behavior at Panga ya Saidi. We compare technological change between the Middle and Later Stone Age with on-site paleoenvironmental manifestations of wider climatic fluctuations in the Late Pleistocene. The principal distinguishing feature of Middle from Later Stone Age technology at Panga ya Saidi is the preference for fine-grained stone, coupled with the creation of small flakes (miniaturization). Our review of the Middle to Later Stone Age transition elsewhere in eastern Africa and across the continent suggests that this broader distinction between the two periods is in fact widespread. We suggest that the Later Stone Age represents new short use-life and multicomponent ways of using stone tools, in which edge sharpness was prioritized over durability