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Background: People with Down syndrome often present with balance deficits, which compromise safety during daily activity. While evidence shows that exercise can improve balance in the Down syndrome population, it is unclear if a telehealth method will elicit similar benefits. We aimed to examine the effects of a virtual exercise program on balance in adults with Down syndrome. Methods: Eighteen low-active participants with Down syndrome completed a 12-week telehealth exercise program based on the Mann Method. Balance testing took place before and after the intervention, which included: TUG, MCTSIB, FICSIT-4, and FRT. This study was registered as a clinical trial on ClinicalTrials.gov, identifier: NCT04647851. Results: Significant improvement was seen in the TUG (p = 0.043), FICSIT-4 (p = 0.019) and FRT (p = 0.019). All participants achieved maximum scores on the MCTSIB in pre- and post-testing. Conclusions: Balance in low-active adults with Down syndrome significantly improved following the telehealth exercise program, which we attribute to the tailored exercises that address visual/vestibular deficits and hip muscle weakness.

Bioturbation (sediment disturbance by animal actions) effects on nutrient cycling and nutrient levels in surface waters are difficult to quantify, in part because the diversity and magnitude of species‐specific influences are poorly understood. These influences may have consequences for the management of the trophic state of freshwater ecosystems. Fish cause bioturbation in freshwater and marine ecosystems by digging in benthic sediments, manipulating periphyton mats while searching for prey and scraping hard substrates while feeding. We used experimental enclosures (2.25 m2) to quantify bioturbation‐mediated phosphorus (P) and nitrogen (N) regeneration from sediment by three species of fish that differ in interactions with the benthos (largemouth bass, Micropterus salmoides; tilapia, Oreochromis spp.; and sailfin catfish, Pterogoplichthys spp.) in shallow eutrophic wetlands in Southern Florida. Tilapia are omnivores that include detritus in their diet (winnowing or ingesting sediments) and dig nests in soft sediments year round, sailfin catfish actively burrow into substrate and consume detritus (digging and ingesting sediments), and largemouth bass are piscivores that do not routinely interact with the benthos when feeding but may dig nests in soft sediment in spawning season (January–April). We quantified the amount of suspended flocculent organic matter and changes in water column nutrients (total phosphorus [TP] and total nitrogen [TN]) in 2‐week trials for each species and estimated the portion of nutrient increases relative to fishless controls that could be attributed to bioturbation‐mediated internal nutrient loading through suspension of organic matter (as opposed to excretion or other sources of nutrient loading). Water column nutrient concentrations increased with increasing biomass for all species, but the bioturbation contribution differed by species. Largemouth bass increased water column nutrient concentrations (TP: 86% and TN: 5% relative to controls) but did not influence water column suspended particulate matter through bioturbation of sediment. Tilapia increased water column nutrients a modest amount (TP: 8%; TN: 15%), of which a small portion was attributed to bioturbation (c. 18% of TP). Sailfin catfish raised water column nutrients substantially (TP: 105%; TN: 46%) and up to 100% of the increased TP was attributed to bioturbation. Sailfin catfish also suppressed algal growth and TP accumulation on the sides of the enclosures and reduced nutrient concentrations of the flocculent sediments. Our results were consistent with our hypothesis that behaviour and foraging traits affect bioturbation contributions to nutrient loading. The results also demonstrated that species with similar net effects like largemouth bass and sailfin catfish, added nutrients via different mechanisms (i.e. excretion vs. bioturbation). Considering the feeding strategies and interactions with the substrate of common fish species may assist managers in meeting nutrient reduction goals for eutrophic wetlands and managed freshwater systems. [ABSTRACT FROM AUTHOR]

The Arctic nearshore surrounding Point Barrow, Alaska, is a dynamic system with complex oceanographic and meteorological processes that drive community composition to change rapidly in space and time. Nearshore fish and zooplankton communities were sampled in the summers of 2013-2015. Spatial, temporal, environmental, and biological drivers of fish community structure in the Arctic nearshore surrounding Point Barrow were investigated using multivariate canonical correspondence analysis (CCA). A CCA model using the 13 most explanatory variables (three environmental, one spatial, four temporal, and five zooplankton abundances) explained 73% of the variance in community structure in this region. Distinct fish communities were identified within the three waterbodies that were studied (Chukchi Sea, Beaufort Sea, and Elson Lagoon), and these distinctions were largely driven by salinity. Species move into the nearshore at various times after landfast ice breaks up, creating an annual succession of species that can be found in these nearshore habitats. Low-latitude species tend to become abundant later in the summer season, whereas true Arctic species are present under the ice or move in shortly after breakup. Arctic species are also more abundant in colder years, whereas low-latitude species dominate during warmer years. The increasing abundance of low-latitude species in the Arctic nearshore may have serious implications for the food webs in these ecosystems as climate change continues. Le littoral arctique entourant la pointe Barrow (Alaska) est un systeme dynamique caracterise par des processus oceanographiques et meteorologiques complexes qui engendrent des changements rapides de la composition des communautes dans le temps et l'espace. Les communautes littorales de poissons et de zooplancton ont ete echantillonnees durant les etes 2013 a 2015. Les facteurs spatiaux, temporels, environnementaux et biologiques qui modulent la structure des communautes de poissons dans la zone littorale arctique entourant la pointe Barrow ont ete examines en utilisant l'analyse canonique des correspondances (ACC) multivariee. Un modele d'ACC integrant les 13 variables les plus explicatives (trois variables environnementales, une spatiale, quatre temporelles et cinq d'abondance du zooplancton) explique 73 % de la variance dans la structure des communautes dans cette region. Differentes communautes de poissons ont ete cernees dans les trois plans d'eau etudies (la mer des Tchouktches, la mer de Beaufort et la lagune d'Elson), ces distinctions etant majoritairement modulees par la salinite. Des especes entrent dans la zone littorale a divers moments apres la debacle de la glace de rive, creant une succession annuelle d'especes pouvant etre observees dans ces habitats littoraux. Les especes de faibles latitudes ont tendance a devenir abondantes plus tard durant l'ete, alors que les especes veritablement arctiques sont presentes sous la glace ou arrivent peu apres la debacle. Les especes arctiques sont aussi plus abondantes durant les annees plus froides, alors que les especes de faibles latitudes predominent durant les annees plus chaudes. Avec la poursuite des changements climatiques, l'augmentation de l'abondance d'especes de faibles latitudes dans la zone littorale arctique pourrait entramer de graves consequences pour les reseaux trophiques dans ces ecosystemes. [Traduit par la Redaction], Introduction Environmental scientists have shifted attention to polar regions where the effects of climate change occur most rapidly (Johannesson et al. 2004). In addition to environmental changes, decreasing sea ice [...]

High-flux pulses of magmatism that make up most of the exposed North American Cordilleran arcs are derived primarily from upper plate lithospheric source materials, and not the mantle wedge as most models would predict, based on a compilation of thousands of previously published Sr, Nd, and O isotopic data. Mass balance calculations show that no more than 50% of that mass can be mantle-derived. Flare-ups must have fundamentally developed simultaneously with crustal/lithospheric thickening, thus implying a connection. Subduction erosion from the trench side, and retroarc shortening from the foreland side are the main tectonic shortening processes that operate in conjunction with high flux magmatism during subduction, and therefore are likely triggers for flare-up events in arc. These arcs represent the sites of crustal differentiation, and thus contribute to net continental growth, only if dense residual lower crust was returned to the convective mantle. Isotopic data shown here suggest that if convective removal of batholithic roots takes place, it must be a consequence and not a cause of episodic flare-ups. The Altiplano-Puna Volcanic Complex in South America may be the most recent continental arc segment in flare-up mode. Keywords: subduction, isotopes, arc magmatism, flare-up, delamination. doi: 10.1130/G23898A.1