Vegetation type is an important predictor of the arctic summer land surface energy budget

Despite the importance of high-latitude surface energy budgets (SEBs) for land-climate interactions in the rapidly changing Arctic, uncertainties in their prediction persist. Here, we harmonize SEB observations across a network of vegetated and glaciated sites at circumpolar scale (1994-2021). Our variance-partitioning analysis identifies vegetation type as an important predictor for SEB-components during Arctic summer (June-August), compared to other SEB-drivers including climate, latitude and permafrost characteristics. Differences among vegetation types can be of similar magnitude as between vegetation and glacier surfaces and are especially high for summer sensible and latent heat fluxes. The timing of SEB-flux summer-regimes (when daily mean values exceed 0 Wm(-2)) relative to snow-free and -onset dates varies substantially depending on vegetation type, implying vegetation controls on snow-cover and SEB-flux seasonality. Our results indicate complex shifts in surface energy fluxes with land-cover transitions and a lengthening summer season, and highlight the potential for improving future Earth system models via a refined representation of Arctic vegetation types.An international team of researchers finds high potential for improving climate projections by a more comprehensive treatment of largely ignored Arctic vegetation types, underscoring the importance of Arctic energy exchange measuring stations.Peer reviewe

Integrating catchment properties in small scale species distribution models of stream macroinvertebrates

Species distribution models are increasingly applied to freshwater ecosystems. Most applications use large scales, coarse resolutions and anthropocentric modelling extents, thus not being able to consider important environmental predictors and ecological processes detectable within a catchment and at finer scales. Moreover, high resolution predictions of species distribution in streams can help improve our understanding of how environmental variables within a catchment affect the distribution of stream macroinvertebrates. We built models at a resolution of 25 m x 25 m for a 488 km(2) catchment in northern Germany to determine whether the spatial approach in which environmental predictors are implemented in the model affects the overall performance. We used predictors from four different categories relevant to freshwater ecosystems: bioclimatic, topographic, hydrologic and land use. Two spatial approaches were tested: a local one, or grid based and a cumulative for the upstream area, or subcatchment specific. Models were evaluated in terms of model performance and accuracy in order to identify the approach best suited for each category, as well as the most important predictor in each. In the case of the land use category, the subcatchment approach made a significant difference, increasing performance. A final model, calibrated with the selected predictors, resulted in the highest model performance and accuracy. Our results indicate that species distribution models perform well and are accurate at high resolutions, within small catchments. We conclude that catchment wide models, especially when using predictors from multiple categories, have the potential to significantly improve modelling framework of species distribution in freshwater ecosystems. The information produced by accurate, small scale, species distribution models can guide managers and conservation practitioners, by predicting the effects of management decisions within a catchment. We suggest that highly resolved predictors be applied in models using the catchment approach. (C) 2014 Elsevier B.V. All rights reserved.Species distribution models are increasingly applied to freshwater ecosystems. Most applications use large scales, coarse resolutions and anthropocentric modelling extents, thus not being able to consider important environmental predictors and ecological processes detectable within a catchment and at finer scales. Moreover, high resolution predictions of species distribution in streams can help improve our understanding of how environmental variables within a catchment affect the distribution of stream macroinvertebrates. We built models at a resolution of 25 m x 25 m for a 488 km(2) catchment in northern Germany to determine whether the spatial approach in which environmental predictors are implemented in the model affects the overall performance. We used predictors from four different categories relevant to freshwater ecosystems: bioclimatic, topographic, hydrologic and land use. Two spatial approaches were tested: a local one, or grid based and a cumulative for the upstream area, or subcatchment specific. Models were evaluated in terms of model performance and accuracy in order to identify the approach best suited for each category, as well as the most important predictor in each. In the case of the land use category, the subcatchment approach made a significant difference, increasing performance. A final model, calibrated with the selected predictors, resulted in the highest model performance and accuracy. Our results indicate that species distribution models perform well and are accurate at high resolutions, within small catchments. We conclude that catchment wide models, especially when using predictors from multiple categories, have the potential to significantly improve modelling framework of species distribution in freshwater ecosystems. The information produced by accurate, small scale, species distribution models can guide managers and conservation practitioners, by predicting the effects of management decisions within a catchment. We suggest that highly resolved predictors be applied in models using the catchment approach. (C) 2014 Elsevier B.V. All rights reserved

Climatic and Catchment-Scale Predictors of Chinese Stream Insect Richness Differ between Taxonomic Groups

Little work has been done on large-scale patterns of stream insect richness in China. We explored the influence of climatic and catchment-scale factors on stream insect (Ephemeroptera, Plecoptera, Trichoptera; EPT) richness across mid-latitude China. We assessed the predictive ability of climatic, catchment land cover and physical structure variables on genus richness of EPT, both individually and combined, in 80 mid-latitude Chinese streams, spanning a 3899-m altitudinal gradient. We performed analyses using boosted regression trees and explored the nature of their influence on richness patterns. The relative importance of climate, land cover, and physical factors on stream insect richness varied considerably between the three orders, and while important for Ephemeroptera and Plecoptera, latitude did not improve model fit for any of the groups. EPT richness was linked with areas comprising high forest cover, elevation and slope, large catchments and low temperatures. Ephemeroptera favoured areas with high forest cover, medium-to-large catchment sizes, high temperature seasonality, and low potential evapotranspiration. Plecoptera richness was linked with low temperature seasonality and annual mean, and high slope, elevation and warm-season rainfall. Finally, Trichoptera favoured high elevation areas, with high forest cover, and low mean annual temperature, seasonality and aridity. Our findings highlight the variable role that catchment land cover, physical properties and climatic influences have on stream insect richness. This is one of the first studies of its kind in Chinese streams, thus we set the scene for more in-depth assessments of stream insect richness across broader spatial scales in China, but stress the importance of improving data availability and consistency through time

The Effect of Interventions to Prevent Type 2 Diabetes on the Development of Diabetic Retinopathy: The DPP/DPPOS Experience

OBJECTIVE To determine whether interventions that slow or prevent the development of type 2 diabetes in those at risk reduce the subsequent prevalence of diabetic retinopathy. RESEARCH DESIGN AND METHODS The Diabetes Prevention Program (DPP) randomized subjects at risk for developing type 2 diabetes because of overweight/obesity and dysglycemia to metformin (MET), intensive lifestyle intervention (ILS), or placebo (PLB) to assess the prevention of diabetes. During the DPP and DPP Outcome Study (DPPOS), we performed fundus photography over time on study participants, regardless of their diabetes status. Fundus photographs were graded using the Early Treatment Diabetic Retinopathy Study grading system, with diabetic retinopathy defined as typical lesions of diabetic retinopathy (microaneurysms, exudates, or hemorrhage, or worse) in either eye. RESULTS Despite reduced progression to diabetes in the ILS and MET groups compared with PLB, there was no difference in the prevalence of diabetic retinopathy between treatment groups after 1, 5, 11, or 16 years of follow-up. No treatment group differences in retinopathy were found within prespecified subgroups (baseline age, sex, race/ethnicity, baseline BMI). In addition, there was no difference in the prevalence of diabetic retinopathy between those exposed to metformin and those not exposed to metformin, regardless of treatment group assignment. CONCLUSIONS Interventions that delay or prevent the onset of type 2 diabetes in overweight/ obese subjects with dysglycemia who are at risk for diabetes do not reduce the development of diabetic retinopathy for up to 20 years

Multicentre evaluation of the Naida CI Q70 sound processor:feedback cochlear implant users and professionals

Disorders of the head and nec

HLA-B(star)57 and IFNL4-Related Polymorphisms Are Associated With Protection Against HIV-1 Disease Progression in Controllers

Background. Human immunodeficiency virus type 1 (HIV-1) controllers maintain HIV-1 viremia at low levels (normally 500 cells/mm(3) for more than 7 years after HIV-1 diagnosis) vs non-LTNP-Cs who developed CD4+ T-cell count