The changing form of Antarctic biodiversity

Antarctic biodiversity is much more extensive, ecologically diverse and biogeographically structured than previously thought. Understanding of how this diversity is distributed in marine and terrestrial systems, the mechanisms underlying its spatial variation, and the significance of the microbiota is growing rapidly. Broadly recognizable drivers of diversity variation include energy availability and historical refugia. The impacts of local human activities and global environmental change nonetheless pose challenges to the current and future understanding of Antarctic biodiversity. Life in the Antarctic and the Southern Ocean is surprisingly rich, and as much at risk from environmental change as it is elsewher

A synergistic approach for evaluating climate model output for ecological applications

Increasing concern about the impacts of climate change on ecosystems is prompting ecologists and ecosystem managers to seek reliable projections of physical drivers of change. The use of global climate models in ecology is growing, although drawing ecologically meaningful conclusions can be problematic. The expertise required to access and interpret output from climate and earth system models is hampering progress in utilizing them most effectively to determine the wider implications of climate change. To address this issue, we present a joint approach between climate scientists and ecologists that explores key challenges and opportunities for progress. As an exemplar, our focus is the Southern Ocean, notable for significant change with global implications, and on sea ice, given its crucial role in this dynamic ecosystem. We combined perspectives to evaluate the representation of sea ice in global climate models. With an emphasis on ecologically-relevant criteria (sea ice extent and seasonality) we selected a subset of eight models that reliably reproduce extant sea ice distributions. While the model subset shows a similar mean change to the full ensemble in sea ice extent (approximately 50% decline in winter and 30% decline in summer), there is a marked reduction in the range. This improved the precision of projected future sea ice distributions by approximately one third, and means they are more amenable to ecological interpretation. We conclude that careful multidisciplinary evaluation of climate models, in conjunction with ongoing modeling advances, should form an integral part of utilizing model output

Genetic pleiotropy between age-related macular degeneration and 16 complex diseases and traits

Background: Age-related macular degeneration (AMD) is a common condition of vision loss with disease development strongly influenced by environmental and genetic factors. Recently, 34 loci were associated with AMD at genome-wide significance. So far, little is known about a genetic overlap between AMD and other complex diseases or disease-relevant traits. Methods: For each of 60 complex diseases/traits with publicly available genome-wide significant association data, the lead genetic variant per independent locus was extracted and a genetic score was calculated for each disease/trait as the weighted sum of risk alleles. The association with AMD was estimated based on 16,144 AMD cases and 17,832 controls using logistic regression. Results: Of the respective disease/trait variance, the 60 genetic scores explained on average 4.8% (0.27-20.69%) and 16 of them were found to be significantly associated with AMD (Q-values \u3c 0.01, p values from \u3c 1.0 × 10-16 to 1.9 × 10-3). Notably, an increased risk for AMD was associated with reduced risk for cardiovascular diseases, increased risk for autoimmune diseases, higher HDL and lower LDL levels in serum, lower bone-mineral density as well as an increased risk for skin cancer. By restricting the analysis to 1824 variants initially used to compute the 60 genetic scores, we identified 28 novel AMD risk variants (Q-values \u3c 0.01, p values from 1.1 × 10-7 to 3.0 × 10-4), known to be involved in cardiovascular disorders, lipid metabolism, autoimmune diseases, anthropomorphic traits, ocular disorders, and neurological diseases. The latter variants represent 20 novel AMD-associated, pleiotropic loci. Genes in the novel loci reinforce previous findings strongly implicating the complement system in AMD pathogenesis. Conclusions: We demonstrate a substantial overlap of the genetics of several complex diseases/traits with AMD and provide statistically significant evidence for an additional 20 loci associated with AMD. This highlights the possibility that so far unrelated pathologies may have disease pathways in common

Role of macronutrients in cotton production

Sound nutrition plays a key role in enhancing cotton yield. As cotton undergoes vegetative and reproductive growth at the same time, its nutritional requirements are dissimilar, compared to other field crops. Cotton is grown as an annual crop with an indeterminate growth pattern. The vegetative branching provides a potential fruiting place except under abiotic and biotic stresses. Moreover, cotton has a deep root system with low density of roots in the surface layer of soils where availability of nutrients is high. The rooting system makes cotton crop more dependent on the subsoil for nutrition. A continuous supply of nutrients is required to sustain morphogenesis. The rate of both nutrients absorption and dry matter production increases progressively during the seedling, vegetative, and fruiting periods and peaks near the end of the bloom period. Nitrogen, phosphorus, and potassium are required in large quantities and are limited in many soils. The deficiencies of macro-and micronutrients decrease plant growth and development, and consequently seed cotton yield is reduced. The deficiency of phosphorous (P), calcium (Ca), potassium (K), boron (B), magnesium (Mg), and zinc (Zn) affects fruit production in cotton than vegetative growth, while the deficiencies of nitrogen (N), sulfur (S), molybdenum (Mo), and manganese (Mn) affect equally vegetative and reproductive growth of cotton. A bevy of literature concerning the role of macronutrients in growth and development is presented in the following paragraphs. © Springer Nature Singapore Pte Ltd. 2020. All rights reserved

Intersession Test-Retest Variability of Microperimetry in Type 2 Macular Telangiectasia

Purpose: Microperimetry is used as an endpoint in type 2 macular telangiectasia (mactel) trials. The change required for defining disease progression depends on measurement error. We determined the threshold of test-retest variability (TRV) of microperimetry in mactel. Methods: A prospective study was done of 24 patients with stable mactel enrolled in a tertiary eye clinic. Each patient underwent three sessions of microperimetry separated by a median of 28 days. An identical testing protocol was used: 4-2 staircase algorithm at 37 loci radial grid covering central 6°. Microperimetry variables were compared across three visits. TRV was quantified by calculating the coefficients of repeatability (CRs) for mean and median foveal sensitivity and the number of loci with dense scotoma (DS) or normal sensitivity (NS). The 95% confidence intervals (CIs) for CRs were calculated. Results: Mean and median foveal sensitivity increased from first to second testing sessions. Test duration, visual acuity, number of loci with DS, and fixation stability remained stable through the three test sessions. The intersession CRs for mean and median foveal sensitivity were 2.6 (95% CI, 1.8-3.3) and 2.4 (95% CI, 1.7-3.1) dB, respectively. CRs for the number of DS and NS loci were 5 and 12 loci. CR for both logBCEA63 and logBCEA95 was 1.0 (95% CI, 0.8-1.2). Conclusions: The first microperimetry examination should be discarded due to learning effects. TRV in foveal sensitivity may be as high as 3.3 and 3.1 dB (∼0.3 log unit; 2× change) for its mean and median. Translational Relevance: Our results have implications for the design of clinical trials in mactel

Intrasession Repeatability and Interocular Symmetry of Foveal Avascular Zone and Retinal Vessel Density in OCT Angiography

PURPOSE: To measure intrasession repeatability and interocular symmetry of the foveal avascular zone area (FAZA) and superficial retinal vessel density (SRVD) using AngioVue Analytics optical coherence tomography angiography (OCTA). METHODS: Fifty healthy individuals were prospectively enrolled. OCTA scans (3 × 3 and 6 × 6 mm) were acquired twice in right and once in left eyes. FAZA (with and without rescaling) and SRVD for 18 regions (whole, fovea, parafovea, six parafoveal subregions, and nine square zones) were compared between two scans in right eyes (repeatability) and between both eyes (symmetry). Coefficients of repeatability (CRs) and limits of agreement (LAs) were calculated. RESULTS: Axial length-based image size rescaling had negligible impact on the intrasession CR of FAZA in both 3 × 3- and 6 × 6-mm images. The intrasession CRs for the foveal SRVD were 3.3% and 6.1% in the 3 × 3- and 6 × 6-mm OCTA images, respectively. Age and axial length did not influence test-retest variability of FAZA or SRVD. The interocular LAs in FAZA (0.039-0.059 mm2) was comparable to its CR. However, the interocular LAs in foveal SRVD were -4.5% to +3.8%, with 13% of the cohort showing an interocular difference greater than the CR. CONCLUSIONS: FAZA repeatability is not influenced by image size correction, and foveal SRVD is more variable in 6 × 6- than 3 × 3-mm OCTA images. Low image quality may contribute to interocular SRVD asymmetry. TRANSLATIONAL RELEVANCE: CRs and LAs can be used to set a threshold for true changes in FAZA and SRVD in longitudinal studies of healthy individuals