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Postural control is an important aspect of physical functioning. To determine whether postural sway complexity could discriminate asymptomatic sedentary postmenopausal women with normal or subnormal physical function from those with lower physical function. Cross-sectional study. Department of Geriatrics, University Hospital of Montpellier. 126 community-dwelling women aged 55 to 76 recruited though public meetings aimed at promoting physical activity in postmenopausal women. Women were asked to stand still on a force platform, either with eyes open (EO) or eyes closed (EC). Physical function was estimated using the Six-Minute Walking Distance (6MWD) test, expressed as a percentage of the predicted 6MWD (%-pred 6MWD) based on age, gender, body height, and weight. In addition to traditional stabilometric measures, dynamical measures (percentage of determinism of recurrence quantification analysis [DETRQA], sample entropy [SampEn] and complexity index of multiscale entropy [CIMSE]) were used to quantify the complexity of center of pressure (COP) time series (DETRQA: predictability, SampEn: regularity, CIMSE: multiscale regularity). None of the traditional stabilometric measures differentiated women with lower (%-pred 6MWD ≤ 85.5%) from those with subnormal or normal (%-pred 6MWD > 85.5%) physical function. Conversely, women with lower physical function showed lower SampEn values in the AP direction in both EO and EC conditions, as well as lower SampEn and higher DETRQA values in the ML direction in EC condition. No significant difference in the CIMSE values was found between the two groups. Lower physical function was found to be associated with lower postural sway complexity (higher regularity and predictability) in asymptomatic sedentary postmenopausal women, especially in the absence of vision. Future work is needed to determine whether a decrease in postural sway complexity could predict future decline in physical function in these women.

We measured deciduous forest soil temperatures under control (unmanipulated) and snow‐free (where snow is manually removed) conditions for four winters (at three soil depths) to determine effects of a snow cover reduction such as may occur as a result of climate change on Vermont forest soils. The four winters we studied were characterized as: ‘cold and snowy’, ‘warm with low snow’, ‘cold with low snow’, and ‘cool with low snow’. Snow‐free soils were colder than controls at 5‐ and 15‐cm depth for all years, and at all depths in the two cold winters. Soil thermal variability generally decreased with both increased snow cover and soil depth. The effect of snow cover on soil freeze‐thaw events was highly dependent on both the depth of snow and the soil temperature. Snow kept the soil warm and reduced soil temperature variability, but often this caused soil to remain near 0°C, resulting in more freeze–thaw events under snow at one or more soil depths. During the ‘cold snowy’ winter, soils under snow had daily averages consistently >0°C, whereas snow‐free soil temperatures commonly dropped below −3°C. During the ‘warm’ year, temperatures of soil under snow were often lower than those of snow‐free soils. The warmer winter resulted in less snow cover to insulate soil from freezing in the biologically active top 30 cm. The possible consequences of increased soil freezing include more root mortality and nutrient loss, which would potentially alter ecosystem dynamics, decrease productivity of some tree species, and increase sugar maple (Acer saccharum Marshall) mortality in northern hardwood forests.

The creation of a mathematical simulation model of photosynthetic microbial mats is important to our understanding of key biogeochemical cycles that may have altered the atmospheres and lithospheres of early Earth. A model is presented here as a tool to integrate empirical results from research on hypersaline mats from Baja California Sur (BCS), Mexico into a computational system that can be used to simulate biospheric inputs of trace gases to the atmosphere. The first version of our model, presented here, calculates fluxes and cycling of O 2, sulfide, and dissolved inorganic carbon (DIC) via abiotic components and via four major microbial guilds: cyanobacteria (CYA), sulfate reducing bacteria (SRB), purple sulfur bacteria (PSB) and colorless sulfur bacteria (CSB). We used generalized Monod-type equations that incorporate substrate and energy limits upon maximum rates of metabolic processes such as photosynthesis and sulfate reduction. We ran a simulation using temperature and irradiance inputs from data collected from a microbial mat in Guerrero Negro in BCS (Mexico). Model O 2, sulfide, and DIC concentration profiles and fluxes compared well with data collected in the field mats. There were some model-predicted features of biogeochemical cycling not observed in our actual measurements. For instance, large influxes and effluxes of DIC across the MBGC mat boundary may reveal previously unrecognized, but real, in situ limits on rates of biogeochemical processes. Some of the short-term variation in field-collected mat O 2 was not predicted by MBGC. This suggests a need both for more model sensitivity to small environmental fluctuations for the incorporation of a photorespiration function into the model.

We evaluated the patterns of variation in the activity of four soil enzymes in oak forests soils at spatial scales from l0s of km to <3 m. The four enzymes (beta-glucosidase, chitinase, phenol oxidase, and acid phosphatase) are specific for substrates that vary widely in lability or recalcitrance. Significant variations in enzyme activity were observed at the regional (among forested areas), topographic (along elevation gradients within a watershed) and single-tree (1 m upslope and downslope of an individual tree) scales, but not at the local scale (contiguous watersheds within forested areas). However, the specific patterns of variation in relation to spatial scale were unique to each enzyme system. Detrended correspondence analysis (DCA) ordination of the activity of the four enzymes in each soil sample suggested a strong nutrient availability gradient underlying these spatial scale differences. Exploratory path analysis produced relatively strong predictive models based on soil nutrients, organic matter, and moisture for all the individual enzymes except phenol oxidase. However, path analysis produced an even stronger model for the activity of all four enzymes together, using the DCA axis scores as the dependent variable. The results indicate that the four enzyme systems could help resolve spatial dependencies at a range of scales and could also be used to develop a scale-independent metric to be used for regional analyses in a geographic information system environment.

This study examined foliar nutrient dynamics and nutrient resorption (retranslocation) in three species of Chilean Nothofagus (Fagaceae) that differed in leaf lifespan and elevational distribution. In our central Chile study area the elevations at which these three species are most abundant increase from N. obliqua (deciduous) at low elevations to N. dombeyi at intermediate elevation and N. pumilio (deciduous) at higher elevations up to treeline. We sampled a single stand at 1680 m in which all three species co-occurred. Nothofagus dombeyi leaves were structurally heavier, with specific leaf mass approximately twice that of the two deciduous species. On a concentration basis, foliar N increased in the order N. dombeyi < N. pumilio < N. oliqua and foliar P increase in the order N. dombeyi < N. obliqua < N. pumilio. However, when the differences in specific leaf mass among species were taken into account by calculating N and P content on a leaf area basis, N. dombeyi had the greatest N and P content. N and P remained relatively constant throughout most of the 4-yr N. dombeyi leaf lifespan, then decreased prior to abscission. Nothofagus dombeyi resorbed significantly less N (44-50%) than did the two deciduous species (63-78%), both on proportional and absolute bases. In contrast, N. pumilio and N. dombeyi resorbed similar amounts of P prior to abscission (40-50%), whereas no significant resorption of P from leaves of N. obliqua was noted. We use these results to clarify the relative importance of environmental gradients associated with elevation vs. genetically fixed leaf lifespans in controlling the nutrient dynamics of these congeneric tree species.

The complexity of natural ecosystems makes it difficult to compare the relative importance of abiotic and biotic factors and to assess the effects of their interactions on ecosystem development. To improve our understanding of ecosystem complexity, we initiated an experiment designed to quantify the main effects and interactions of several factors that are thought to affect nutrient export from developing forest ecosystems. Using a replicated 2 × 2 × 4 factorial experiment, we quantified the main effects of these factors and the factor interactions on annual calcium, magnesium, and potassium export from field mesocosms over 4 years for two Vermont locations, two soils, and four different tree seedling communities. We found that the main effects explained 56%-97% of total variation in nutrient export. Abiotic factors (location and soil) accounted for a greater percentage of the total variation in nutrient export (47%-94%) than the biotic factor (plant community) (2%-15%). However, biotic control over nutrient export was significant, even when biomass was minimal. Factor interactions were often significant, but they explained less of the variation in nutrient export (1%-33%) than the main effects. Year-to-year fluctuations influenced the relative importance of the main effects in determining nutrient export and created factor interactions between most of the explanatory variables. Our study suggests that when research is focused on typically used main effects, such as location and soil, and interactions are aggregated into overall error terms, important information about the factors controlling ecosystem processes can be lost.

To contribute to the un-derstanding of the long-term effects of atmospheric deposition on forests of eastern North America, we conducted a set of greenhouse experiments designed to determine the effect of reduced soil Ca:Al ratio on growth and competitive interactions of two common, co-occuring tree species. Second year seedlings of northern red oak (Quercus rubra), an ectomycorrhizal species currently declining in abundance in eastern North America, and yellow-poplar (Liriodendron tulipifera), an arbuscular mycorrhizal species currently increasing in abundance, were grown in intraspecific or interspecific pairs in either field soil or silica sand, and at Ca:Al ratio of 4 or 100. Overall relative growth rates (RGR) of the two species were similar; however, red oak allocated more new biomass to stem wood while yellow-poplar allocated biomass to leaves and roots. Reducing the Ca:Al ratio from 100 to 4 had no major effect on red oak growth but reduced RGR, leaf production, and N uptake significantly in yellow-poplar; leaf [N] was significantly higher in red oaks grown at Ca:Al of 4 than 100. Yellow-poplar grew better in interspecific pairs than in intraspecific pairs. In contrast, competitive mode had no effect on red oak growth. Analysis of soil N pools indicated that red oak was unable to make use of the inorganic N added during biweekly nutrient solution additions. In contrast yellow-poplar was able to deplete soil N pools rapidly and its growth was probably N limited at Ca:Al ratio of 100. The critical Ca:Al threshold for growth decline appeared to be <4.0 for red oak and >4.0 for yellow-poplar. Yellow-poplar outcompetes red oak under N enriched conditions, but its competitive advantage decreases at lowered Ca:Al ratio. We hypothesize that the current shift in tree species composition observed in eastern North America may be the consequence of N enrichment, but that the direction of these shifts may reverse as lowered Ca:Al ratio and other effects of N saturation develop.

To describe the historical evolution of the International Nursing Association for Clinical Simulation and Learning's (INACSL) Standards of Best Practice: Simulation. The establishment of simulation standards began as a concerted effort by the INACSL Board of Directors in 2010 to provide best practices to design, conduct, and evaluate simulation activities in order to advance the science of simulation as a teaching methodology. A comprehensive review of the evolution of INACSL Standards of Best Practice: Simulation was conducted using journal publications, the INACSL website, INACSL member survey, and reports from members of the INACSL Standards Committee. The initial seven standards, published in 2011, were reviewed and revised in 2013. Two new standards were published in 2015. The standards will continue to evolve as the science of simulation advances. As the use of simulation-based experiences increases, the INACSL Standards of Best Practice: Simulation are foundational to standardizing language, behaviors, and curricular design for facilitators and learners.

Hereditary hearing loss is a clinically and genetically heterogeneous disorder. More than 80 genes have been implicated to date, and with the advent of targeted genomic enrichment and massively parallel sequencing (TGE+MPS) the rate of novel deafness-gene identification has accelerated. Here we report a family segregating post-lingual progressive autosomal dominant non-syndromic hearing loss (ADNSHL). After first excluding plausible variants in known deafness-causing genes using TGE+MPS, we completed whole exome sequencing in three hearing-impaired family members. Only a single variant, p.Arg185Pro in HOMER2, segregated with the hearing-loss phenotype in the extended family. This amino acid change alters a highly conserved residue in the coiled-coil domain of HOMER2 that is essential for protein multimerization and the HOMER2-CDC42 interaction. As a scaffolding protein, HOMER2 is involved in intracellular calcium homeostasis and cytoskeletal organization. Consistent with this function, we found robust expression in stereocilia of hair cells in the murine inner ear and observed that over-expression of mutant p.Pro185 HOMER2 mRNA causes anatomical changes of the inner ear and neuromasts in zebrafish embryos. Furthermore, mouse mutants homozygous for the targeted deletion of Homer2 present with early-onset rapidly progressive hearing loss. These data provide compelling evidence that HOMER2 is required for normal hearing and that its sequence alteration in humans leads to ADNSHL through a dominant-negative mode of action.

Frailty tends to be considered as a major risk for adverse outcomes in older persons, but some important aspects remain matter of debate. The purpose of this paper is to present expert's positions on the main aspects of the frailty syndrome in the older persons. Workshop organized by International Association of Gerontology and Geriatrics (IAGG), World Health Organization (WHO) and Société Française de Gériatrie et de Gérontologie (SFGG). Frailty is widely recognized as an important risk factor for adverse health outcomes in older persons. This can be of particular value in evaluating non-disabled older persons with chronic diseases but today no operational definition has been established. Nutritional status, mobility, activity, strength, endurance, cognition, and mood have been proposed as markers of frailty. Another approach calculates a multidimensional score ranging from “very fit” to “severely frail,” but it is difficult to apply into the medical practice. Frailty appears to be secondary to multiple conditions using multiple pathways leading to a vulnerability to a stressor. Biological (inflammation, loss of hormones), clinical (sarcopenia, osteoporosis etc.), as well as social factors (isolation, financial situation) are involved in the vulnerability process. In clinical practice, detection of frailty is of major interest in oncology because of the high prevalence of cancer in older persons and the bad tolerance of the drug therapies. Presence of frailty should also be taken into account in the definition of the cardiovascular risks in the older population. The experts of the workshop have listed the points reached an agreement and those must to be a priority for improving understanding and use of frailty syndrome in practice. Frailty in older adults is a syndrome corresponding to a vulnerability to a stressor. Diagnostic tools have been developed but none can integrate at the same time the large spectrum of factors and the simplicity asked by the clinical practice. An agreement with an international common definition is necessary to develop screening and to reduce the morbidity in older persons.