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Predicting the dynamics of ecosystems requires an understanding of how trophic interactions respond to environmental change. In Antarctic marine ecosystems, food web dynamics are inextricably linked to sea ice conditions that affect the nature and magnitude of primary food sources available to higher trophic levels. Recent attention on the changing sea ice conditions in polar seas highlights the need to better understand how marine food webs respond to changes in such broad-scale environmental drivers. This study investigated the importance of sea ice and advected primary food sources to the structure of benthic food webs in coastal Antarctica. We compared the isotopic composition of several seafloor taxa (including primary producers and invertebrates with a variety of feeding modes) that are widely distributed in the Antarctic. We assessed shifts in the trophic role of numerically dominant benthic omnivores at five coastal Ross Sea locations. These locations vary in primary productivity and food availability, due to their different levels of sea ice cover, and proximity to polynyas and advected primary production. The [delta][sup.15]N signatures and isotope mixing model results for the bivalves Laternula elliptica and Adamussium colbecki and the urchin Sterechinus neumeyeri indicate a shift from consumption of a higher proportion of detritus at locations with more permanent sea ice in the south to more freshly produced algal material associated with proximity to ice-free water in the north and east. The detrital pathways utilized by many benthic species may act to dampen the impacts of large seasonal fluctuations in the availability of primary production. The limiting relationship between sea ice distribution and in situ primary productivity emphasizes the role of connectivity and spatial subsidies of organic matter in fueling the food web. Our results begin to provide a basis for predicting how benthic ecosystems will respond to changes in sea ice persistence and extent along environmental gradients in the high Antarctic. Key words: Antarctica; benthic food webs; coastal sea ice; omnivory; Ross Sea; spatial subsidies; stable isotopes.

Background: Although claims of increased injury rates with Thursday night National Football League (NFL) games exist, a paucity of data exist substantiating these claims. Purpose: To evaluate the effect of rest between games on in-game injury rates as it pertains to overall injury incidence, location, and player position. Study Design: Descriptive epidemiologic study. Methods: Data were obtained from official NFL game books for regular season games from all 32 teams for the 2013-2016 seasons. All in-game injuries recorded in official game books were included. Rest periods between games were classified as short (4 days), regular (6-8 days), or long (≥10 days). Overall observed injury rates per team-game were analyzed in relation to different rest periods using negative binomial regression. For results with significant overall findings, pairwise comparisons were tested using the Wald chi-square test. Exploratory secondary analyses were performed in a similar fashion to assess differences in injury rates for the different rest periods when stratified by anatomic location and player position. Results: A total of 2846 injuries were identified throughout the 4 seasons. There was an overall significant difference in injuries per team-game between short, regular, and long rest (P =.01). With short rest, an observed mean of 1.26 injuries per game (95% CI, 1.06-1.49) was significantly different from the 1.53 observed injuries per game with regular rest (95% CI, 1.46-1.60; P =.03), but not compared with the 1.34 observed injuries per game with long rest (P =.56). For player position, only the tight end, linebacker, and fullback group demonstrated significant differences between the injury rates for different rest categories. Quarterback was the only position with more injuries during games played on Thursday compared with both regular and long rest. This specific analysis was underpowered and the difference was not significant (P =.08). No differences were found regarding injury rates in correlation with differences in rest periods with different injury locations. Conclusion: A short rest period between games is not associated with increased rates of observed injuries reported in NFL game books; rather, our data suggest there are significantly fewer injuries for Thursday night games compared with games played on regular rest. Future research correlating rest and quarterback injury rates is warranted. [ABSTRACT FROM AUTHOR]

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Presents a field experiment that investigated the effect of availability of shelter on the foraging behavior of the sea urchin `Centrostephanus rodgersii' and on the abundance of benthic invertebrates and algae. Study location; Experimental design of the habitat translocation experiment; Discussion.

Presents information on a study which examined reproduction in the diadematoid sea urchin Centrostephanus rodgersii in contrasting habitats along the coast of New South Wales, Australia. Methodology of the study; Results and discussion on the study.

Value chains are key pathways within food systems and an important focus for analysis and policy intervention. A systematic scoping review was used to examine how different value chain approaches consider food security and nutrition, with particular attention to examples of how these approaches can simultaneously address additional social, economic or environmental outcomes. Value chain research on food security and nutrition addressed multiple outcomes within the social dimension, and across social and economic dimensions, although few studies incorporated the environmental dimension. While current value chain approaches are useful to parse out problems within a food system, they may miss opportunities for more integrated analyses, particularly in integrating sustainability dimensions. • Value chain approaches are useful to understand issues within food systems. • Environment objectives are poorly incorporated in value chain food security studies. • Surveys and mapping were the most frequently used tools. • Opportunity exists for more integrated value chain analyses. • Tools that easily undertake broader analysis can complement value chain research. [ABSTRACT FROM AUTHOR]

Declines in strength and power are cardinal symptoms of Parkinson's disease (PD), a progressive neuromuscular disorder. Progressive resistance training (PRT) has been shown to reduce a wide variety of PD-related motor deficits; however, no study has examined differences between the two most common RT methodologies utilized in this population, high-load, low velocity strength training (ST) and low-load, high-velocity power training (PT). The primary purpose of this study was to compare the effects of ST and PT on measures of strength, power, balance and functional movement in persons with PD. Thirty-five persons with mild to moderate PD (Hoehm and Yahr Stages = 1–3; UPDRS Part III = 30.6 ± 14.0) were randomized into either a ST or PT group involving 12 weeks of supervised PRT (2 visits per week). Leg press (LP) and chest press (CP) muscular strength (1RM) and muscular peak power (PP) were assessed before and after the twelve week training period as primary outcome measures. In addition, secondary measures of balance (Berg Balance Assessment (BBA), dynamic posturography (DMA), Modified Falls Efficacy Scale (MFES)), functional movement (timed up-and-go), and quality of life (PDQ-39 summary index and Mobility subscore) were obtained at the same time points, given the impact of PD symptoms on fall probability and independence. Repeated measures ANCOVA revealed significant improvements in LP 1RM (M diff = 54.89 kg, 95% CI: 43.38, 66.40; p <.05; d = 3.38) and CP 1RM (M diff = 7.33 kg, 95% CI: 4.75, 9.91; p <.05; d = 2.02). Additionally, significant improvements were seen in LP PP (M diff = 112.27 W, 95% CI: 56.03, 168.51; p <.05; d = 1.42) and CP PP (M diff = 52.1 W, 95% CI: 23.38, 80.86; p =.001; d = 1.29). No significant improvements were seen for any secondary outcome measures, however BBA scores were shown to significantly decrease following the intervention (M diff = −1.686, 95% CI: −2.89, −0.482; p =.007 d = −0.96), although this change did not reach clinical significance (clinically meaningful change = ±4.0). In addition, the ST group demonstrated significantly poorer PDQ-39 SI scores (M diff = 4.96, 95% CI: 0.54, 9.38; p =.029), whereas the entire sample showed significantly poorer PDQ-39 MOB scores (M diff = 4.80, 95% CI: 0.17, 9.43; p =.043; d = 0.71). Both ST and PT appear to be effective at reducing the neuromuscular deficits associated with PD; however, the use of these interventions for improving functional performance was not supported. • Strength and power training induce similar adaptations in older persons with PD. • Similar responses allow greater flexibility during training prescriptions. • Strength and power transfers to daily activities may require movement-specific training. • Strength and power training appear equally tolerable in persons with PD. [ABSTRACT FROM AUTHOR]