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A tenet of ecology is that temporal variability in ecological structure and processes tends to decrease with increasing spatial scales (from locales to regions) and levels of biological organization (from populations to communities). However, patterns in temporal variability across trophic levels and the mechanisms that produce them remain poorly understood. Here we analyzed the abundance time series of spatially structured communities (i.e., metacommunities) spanning basal resources to top predators from 355 freshwater sites across three continents. Specifically, we used a hierarchical partitioning method to disentangle the propagation of temporal variability in abundance across spatial scales and trophic levels. We then used structural equation modeling to determine if the strength and direction of relationships between temporal variability, synchrony, biodiversity, and environmental and spatial settings depended on trophic level and spatial scale. We found that temporal variability in abundance decreased from producers to tertiary consumers but did so mainly at the local scale. Species population synchrony within sites increased with trophic level, whereas synchrony among communities decreased. At the local scale, temporal variability in precipitation and species diversity were associated with population variability (linear partial coefficient, β = 0.23) and population synchrony (β = -0.39) similarly across trophic levels, respectively. At the regional scale, community synchrony was not related to climatic or spatial predictors, but the strength of relationships between metacommunity variability and community synchrony decreased systematically from top predators (β = 0.73) to secondary consumers (β = 0.54), to primary consumers (β = 0.30) to producers (β = 0). Our results suggest that mobile predators may often stabilize metacommunities by buffering variability that originates at the base of food webs. This finding illustrates that the trophic structure of metacommunities, which integrates variation in organismal body size and its correlates, should be considered when investigating ecological stability in natural systems. More broadly, our work advances the notion that temporal stability is an emergent property of ecosystems that may be threatened in complex ways by biodiversity loss and habitat fragmentation., (© 2023 The Authors. Ecology published by Wiley Periodicals LLC on behalf of The Ecological Society of America.)

Freshwater ecosystems, including lakes, streams, and wetlands, are responsive to climate change and other natural and anthropogenic stresses. These ecosystems are frequently hydrologically and ecologically connected with one another and their surrounding landscapes, thereby integrating changes throughout their watersheds. The responses of any given freshwater ecosystem to climate change depend on the magnitude of climate forcing, interactions with other anthropogenic and natural changes, and the characteristics of the ecosystem itself. Therefore, the magnitude and manner in which freshwater ecosystems respond to climate change is difficult to predict a priori . We present a conceptual model to elucidate how freshwater ecosystems are altered by climate change. We identify eleven indicators that describe the response of freshwater ecosystems to climate change, discuss their potential value and limitations, and describe supporting measurements. Indicators are organized in three inter-related categories: hydrologic, water quality, and ecosystem structure and function. The indicators are supported by data sets with a wide range of temporal and spatial coverage, and they inform important scientific and management needs. Together, these indicators improve the understanding and management of the effects of climate change on freshwater ecosystems.

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation., (© 2021 The Authors. Ecology Letters published by John Wiley & Sons Ltd.)

River managers strive to use the best available science to sustain biodiversity and ecosystem function. To achieve this goal requires consideration of processes at different scales. Metacommunity theory describes how multiple species from different communities potentially interact with local-scale environmental drivers to influence population dynamics and community structure. However, this body of knowledge has only rarely been used to inform management practices for river ecosystems. In this paper, we present a conceptual model outlining how the metacommunity processes of local niche sorting and dispersal can influence the outcomes of management interventions and provide a series of specific recommendations for applying these ideas as well as research needs. In all cases, we identify situations where traditional approaches to riverine management could be enhanced by incorporating an understanding of metacommunity dynamics. A common theme is developing guidelines for assessing the metacommunity context of a site or region, evaluating how that context may affect the desired outcome, and incorporating that understanding into the planning process and methods used. To maximize the effectiveness of management activities, scientists and resource managers should update the toolbox of approaches to riverine management to reflect theoretical advances in metacommunity ecology.

Emerging evidence indicates that a strong relationship exists between brain regenerative therapies and nutrition. Early life nutrition plays an important role during embryonic brain development, and there are clear consequences to an imbalance in nutritional factors on both the production and survival of mature neuronal populations and the infant's risk of diseases in later life. Our research and that of others suggest that vitamins play a fundamental role in the formation of neurons and their survival. There is a growing body of evidence that nicotinamide, the water-soluble amide form of vitamin B3, is implicated in the conversion of pluripotent stem cells to clinically relevant cells for regenerative therapies. This study investigated the ability of nicotinamide to promote the development of mature catecholaminergic neuronal populations (associated with Parkinson's disease) from mouse embryonic stem cells, as well as investigating the underlying mechanisms of nicotinamide's action. Nicotinamide selectively enhanced the production of tyrosine hydroxylase-expressing neurons and serotonergic neurons from mouse embryonic stem cell cultures (Sox1GFP knock-in 46C cell line). A 5-Ethynyl-2´-deoxyuridine (EdU) assay ascertained that nicotinamide, when added in the initial phase, reduced cell proliferation. Nicotinamide drove tyrosine hydroxylase-expressing neuron differentiation as effectively as an established cocktail of signalling factors, reducing the proliferation of neural progenitors and accelerating neuronal maturation, neurite outgrowth and neurotransmitter expression. These novel findings show that nicotinamide enhanced and enriched catecholaminergic differentiation and inhibited cell proliferation by directing cell cycle arrest in mouse embryonic stem cell cultures, thus driving a critical neural proliferation-to-differentiation switch from neural progenitors to neurons. Further research into the role of vitamin metabolites in embryogenesis will significantly advance cell-based regenerative medicine, and help realize their role as crucial developmental signalling molecules in brain development., Competing Interests: The authors have declared that no competing interests exist.

Inconsistency in taxonomic identification and analyst bias impede the effective use of diatom data in regional and national stream and lake surveys. In this study, we evaluated the effect of existing protocols and a revised protocol on the precision of diatom species counts. The revised protocol adjusts five elements of sample preparation, taxon identification and enumeration, and quality control (QC) samples. We used six independent datasets to assess the effect of the adjustments on analytical outcomes. The first dataset was produced by five analysts from three laboratories following a standard protocol (Charles et al. 2002). The remaining datasets were produced by 2-3 analysts in 1-3 laboratories following a revised protocol. The revised protocol included the following modifications: 1) use of Battarbee settling chambers to prepare coverslips, 2) development of coordinated pre-count voucher floras based on morphological operational taxonomic units (mOTUs), 3) random assignment of samples to analysts, 4) post-count identification and documentation of taxa, and 5) increased QC samples. The revised protocol reduced taxonomic bias, as measured by reduction in analyst signal, and improved similarity among QC samples. Reduced taxonomic bias improves the performance of biological assessments, facilitates transparency across studies, and refines estimates of diatom species distributions.

Background: The nature and extent of inflammation seen in multiple sclerosis (MS) varies throughout the course of the disease. Changes seen in CD4+ T-helper cells in relapsing-remitting (RR) MS and secondary progressive (SP) MS might differ qualitatively and/or quantitatively., Objective: The objective of this paper is to study the frequencies of all major CD4+ T-helper subtypes - Th17, Th22 and Th1 lineage cells - in relapse, remission and secondary progression alongside CCR6 status, a chemokine receptor involved in migration of these cells into the central nervous system., Methods: We compared 100 patients (50 RRMS and 50 SPMS) and 50 healthy volunteers and performed flow cytometric analysis of lymphocytes in blood samples., Results: We demonstrated raised frequencies of various cell types along the Th17 axis; Th17, Th17.1 (IL-17+ interferon gamma+) and dual IL-17+ IL-22+ cells in RRMS. Th22 and CCR6+ Th1 cells (nonclassical Th1) were also increased in RRMS. All these cells were CCR6+. Only Th17 frequencies were elevated in SPMS., Conclusions: Increased frequencies of Th17 cells are implicated both in RRMS and SPMS. The CCR6 pathway includes Th17, Th22 and Th1 nonclassical cells, of which Th22 and Th1 cells represent the greatest subsets in MS., (© The Author(s) 2020.)

Species reintroductions - the translocation of individuals to areas in which a species has been extirpated with the aim of re-establishing a self-sustaining population - have become a widespread practice in conservation biology. Reintroduction projects have tended to focus on terrestrial vertebrates and, to a lesser extent, fishes. Much less effort has been devoted to the reintroduction of invertebrates into restored freshwater habitats. Yet, reintroductions may improve restoration outcomes in regions where impoverished regional species pools limit the self-recolonisation of restored freshwaters. We review the available literature on macroinvertebrate reintroductions, focusing on identifying the intrinsic and extrinsic factors that determine their success or failure. Our study reveals that freshwater macroinvertebrate reintroductions remain rare, are often published in the grey literature and, of the attempts made, approximately one-third fail. We identify life-cycle complexity and remaining stressors as the two factors most likely to affect reintroduction success, illustrating the unique challenges of freshwater macroinvertebrate reintroductions. Consideration of these factors by managers during the planning process and proper documentation - even if a project fails - may increase the likelihood of successful outcomes in future reintroduction attempts of freshwater macroinvertebrates., (© 2018 Cambridge Philosophical Society.)

Salinization of surface waters is a global environmental issue that can pose a regional risk to freshwater organisms, potentially leading to high environmental and economic costs. Global environmental change including climate and land use change can increase the transport of ions into surface waters. We fit both multiple linear regression (LR) and random forest (RF) models on a large spatial dataset to predict Ca 2+ (266 sites), Mg 2+ (266 sites), and [Formula: see text] (357 sites) ion concentrations as well as electrical conductivity (EC-a proxy for total dissolved solids with 410 sites) in German running water bodies. Predictions in both types of models were driven by the major factors controlling salinity including geologic and soil properties, climate, vegetation and topography. The predictive power of the two types of models was very similar, with RF explaining 71-76% of the spatial variation in ion concentrations and LR explaining 70-75% of the variance. Mean squared errors for predictions were all smaller than 0.06. The factors most strongly associated with stream ion concentrations varied among models but rock chemistry and climate were the most dominant. The RF model was subsequently used to forecast the changes in EC that were likely to occur for the period of 2070 to 2100 in response to just climate change-i.e. no additional effects of other anthropogenic activities. The future forecasting shows approximately 10% and 15% increases in mean EC for representative concentration pathways 2.6 and 8.5 (RCP2.6 and RCP8.5) scenarios, respectively.This article is part of the theme issue 'Salt in freshwaters: causes, ecological consequences and future prospects'., (© 2018 The Author(s).)

Lentic small water bodies (LSWBs) deteriorate owing to anthropogenic activities, such as untreated domestic and agricultural waste disposal. Moreover, different turnover mechanisms occur during different seasons, contributing to nutrient enrichment and consequent degradation of LSWBs. However, understanding their spatial, temporal, and vertical variations during different seasons is understudied. In addition, studies on the variation in water quality under varying rainfall and land-use conditions are limited. Therefore, in this study, three LSWBs located in Northern India were studied during the pre-monsoon and monsoon seasons (December 2022 to October 2023). Total nitrogen (TN), chlorophyll-a (Chl-a), total phosphorus (TP), temperature, pH, dissolved oxygen (DO), total dissolved solids (TDS), chemical oxygen demand (COD), secchi disk depth (SDD), and water level (WL) were measured monthly. Sentinel-2 and CHIRPS pentad data were used for land use, land cover classification, and rainfall analysis. The spatial analysis indicates that the seasonal shift affects the water quality distribution, especially near the inlets and at the edges. The overall concentrations of TN and TP decreased during the monsoon season; however, they increased significantly at the inlets of the LSWBs. On the other hand, the Chl-a concentration shifted towards the edges due to the inflow during the monsoon. Temporal analysis also suggests that the arrival of the monsoon lowers pH, DO, and TDS. However, the concentrations of TN and TP increased because of agricultural runoff. Chl-a and COD show distinct variations due to the individual LSWBs' local conditions. Vertical variability analysis demonstrated pH, temperature, and TN stratification during the pre-monsoon period. However, during the monsoon, stratification is less significant due to intermixing. Redundancy analysis (RDA) showed that land use and rainfall patterns affected the water quality of LSWB 1, 2, and 3 by 53.49%, 81.62%, and 92.64%, respectively. This shows that land use, land cover, and rainfall changes affect the water quality of LSWBs. This study highlights the negative impact of runoff from agricultural land use as the main factor responsible for increased nutrient levels in the LSWBs., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Consensus has emerged in the literature that increased biodiversity enhances the capacity of ecosystems to perform multiple functions. However, most biodiversity/ecosystem function studies focus on a single ecosystem, or on landscapes of homogenous ecosystems. Here, we investigate how increased landscape-level environmental dissimilarity may affect the relationship between different metrics of diversity (α, β, or γ) and ecosystem function. We produced a suite of simulated landscapes, each of which contained four experimental outdoor aquatic mesocosms. Differences in temperature and nutrient conditions of the mesocosms allowed us to simulate landscapes containing a range of within-landscape environmental heterogeneities. We found that the variation in ecosystem functions was primarily controlled by environmental conditions, with diversity metrics accounting for a smaller (but significant) amount of variation in function. When landscapes were more homogeneous, α, β, and γ diversity was not associated with differences in primary production, and only γ was associated with changes in decomposition. In these homogeneous landscapes, differences in these two ecosystem functions were most strongly related to nutrient and temperature conditions in the ecosystems. However, as landscape-level environmental dissimilarity increased, the relationship between α, β, or γ and ecosystem functions strengthened, with β being a greater predictor of variation in decomposition at the highest levels of environmental dissimilarity than α or γ. We propose that when all ecosystems in a landscape have similar environmental conditions, species sorting is likely to generate a single community composition that is well suited to those environmental conditions, β is low, and the efficiency of diversity-ecosystem function couplings is similar across communities. Under this low β, the effect of abiotic conditions on ecosystem function will be most apparent. However, when environmental conditions vary among ecosystems, species sorting pressures are different among ecosystems, producing different communities among locations in a landscape. These conditions lead to stronger relationships between β and the magnitude of ecosystem functions. Our results illustrate that abiotic conditions and the homogeneity of communities influence ecosystem function expressed at the landscape scale., (© 2018 by the Ecological Society of America.)

Air temperature at the northernmost latitudes is predicted to increase steeply and precipitation to become more variable by the end of the 21st century, resulting in altered thermal and hydrological regimes. We applied five climate scenarios to predict the future (2070-2100) benthic macroinvertebrate assemblages at 239 near-pristine sites across Finland (ca. 1200 km latitudinal span). We used a multitaxon distribution model with air temperature and modeled daily flow as predictors. As expected, projected air temperature increased the most in northernmost Finland. Predicted taxonomic richness also increased the most in northern Finland, congruent with the predicted northwards shift of many species' distributions. Compositional changes were predicted to be high even without changes in richness, suggesting that species replacement may be the main mechanism causing climate-induced changes in macroinvertebrate assemblages. Northern streams were predicted to lose much of the seasonality of their flow regimes, causing potentially marked changes in stream benthic assemblages. Sites with the highest loss of seasonality were predicted to support future assemblages that deviate most in compositional similarity from the present-day assemblages. Macroinvertebrate assemblages were also predicted to change more in headwaters than in larger streams, as headwaters were particularly sensitive to changes in flow patterns. Our results emphasize the importance of focusing protection and mitigation on headwater streams with high-flow seasonality because of their vulnerability to climate change., (© 2018 John Wiley & Sons Ltd.)

Introduction: Vitamin B3 has been shown to play an important role during embryogenesis. Specifically, there is growing evidence that nicotinamide, the biologically active form of vitamin B3, plays a critical role as a morphogen in the differentiation of stem cells to mature cell phenotypes, including those of the central nervous system (CNS). Detailed knowledge of the action of small molecules during neuronal differentiation is not only critical for uncovering mechanisms underlying lineage-specification, but also to establish more effective differentiation protocols to obtain clinically relevant cells for regenerative therapies for neurodegenerative conditions such as Huntington's disease (HD). Thus, this study aimed to investigate the potential of nicotinamide to promote the conversion of stem cells to mature CNS neurons., Methods: Nicotinamide was applied to differentiating mouse embryonic stem cells (mESC; Sox1GFP knock-in 46C cell line) during their conversion towards a neural fate. Cells were assessed for changes in their proliferation, differentiation and maturation; using immunocytochemistry and morphometric analysis methods., Results: Results presented indicate that 10 mM nicotinamide, when added at the initial stages of differentiation, promoted accelerated progression of ESCs to a neural lineage in adherent monolayer cultures. By 14 days in vitro (DIV), early exposure to nicotinamide was shown to increase the numbers of differentiated βIII-tubulin-positive neurons. Nicotinamide decreased the proportion of pluripotent stem cells, concomitantly increasing numbers of neural progenitors at 4 DIV. These progenitors then underwent rapid conversion to neurons, observed by a reduction in Sox 1 expression and decreased numbers of neural progenitors in the cultures at 14 DIV. Furthermore, GABAergic neurons generated in the presence of nicotinamide showed increased maturity and complexity of neurites at 14 DIV. Therefore, addition of nicotinamide alone caused an accelerated passage of pluripotent cells through lineage specification and further to non-dividing mature neurons., Conclusions: Our results show that, within an optimal dose range, nicotinamide is able to singly and selectively direct the conversion of embryonic stem cells to mature neurons, and therefore may be a critical factor for normal brain development, thus supporting previous evidence of the fundamental role of vitamins and their metabolites during early CNS development. In addition, nicotinamide may offer a simple effective supplement to enhance the conversion of stem cells to clinically relevant neurons.

Streams and rivers are important conduits of terrestrially derived carbon (C) to atmospheric and marine reservoirs. Leaf litter breakdown rates are expected to increase as water temperatures rise in response to climate change. The magnitude of increase in breakdown rates is uncertain, given differences in litter quality and microbial and detritivore community responses to temperature, factors that can influence the apparent temperature sensitivity of breakdown and the relative proportion of C lost to the atmosphere vs. stored or transported downstream. Here, we synthesized 1025 records of litter breakdown in streams and rivers to quantify its temperature sensitivity, as measured by the activation energy (E a , in eV). Temperature sensitivity of litter breakdown varied among twelve plant genera for which E a could be calculated. Higher values of E a were correlated with lower-quality litter, but these correlations were influenced by a single, N-fixing genus (Alnus). E a values converged when genera were classified into three breakdown rate categories, potentially due to continual water availability in streams and rivers modulating the influence of leaf chemistry on breakdown. Across all data representing 85 plant genera, the E a was 0.34 ± 0.04 eV, or approximately half the value (0.65 eV) predicted by metabolic theory. Our results indicate that average breakdown rates may increase by 5-21% with a 1-4 °C rise in water temperature, rather than a 10-45% increase expected, according to metabolic theory. Differential warming of tropical and temperate biomes could result in a similar proportional increase in breakdown rates, despite variation in E a values for these regions (0.75 ± 0.13 eV and 0.27 ± 0.05 eV, respectively). The relative proportions of gaseous C loss and organic matter transport downstream should not change with rising temperature given that E a values for breakdown mediated by microbes alone and microbes plus detritivores were similar at the global scale., (© 2017 John Wiley & Sons Ltd.)

An initial and comprehensive map of ecological regions across the conterminous United States was provided by Omernik in 1987. Because that paper was the most-cited published by the Annals of the American Association of Geographers, we sought to assess and quantify its contribution to science. To do so, we conducted a scientometric analysis to address the following main questions: 1) What are the temporal and spatial citation trends? We expected that Omernik's paper would still be employed 36 years after its publication, and mostly in the United States of America. 2) For what types of environments and organisms has it been applied? Based on its generality, we expected that it had been applied to both terrestrial and aquatic ecosystems. 3) What are the main applications of Omernik's article? We predicted that it would mostly be used for describing and delineating study sites and management areas, as well as for selecting regional reference sites. The number of citations presented a positive temporal increase, indicating its continued applicability. Most papers dealt with aquatic environments, mainly in streams carried out predominantly in the United States of America, as was one of its earliest applications. The usefulness of ecoregions for assessing and managing biotic and abiotic patterns and distributions were the main topics addressed by scientists. Ecoregions have offered a general framework for developing regional expectations and rational regional management policies across large areas, as was their original intent. In addition, ecoregion maps were used for communicating patterns-or the lack of them-to interested scientists, citizens, and decision-makers. That comprehensiveness of Omernik's ecoregion approach has led to its widespread applicability and continued usefulness to a diverse set of scientific and management disciplines., (© 2023. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Road salt poses a threat to the quality of soils and water resources. Wetlands located in salt contaminated areas are at risk of experiencing lower plant and animal species diversity. Therefore, it is critical to understand how modifications to salt application rates and hydrological events impact wetland water quality. Here, we use chloride mass flux, discharge, groundwater chloride concentration, meteorological, and salt application data from 2012–2020 to estimate chloride accumulation and outflux rates in the Kampoosa Bog subwatersheds, located in Stockbridge and Lee, Massachusetts, and bordered by major highways (Interstate-90 and U.S. Route 7). We also investigate the correlation between wetland size and chloride retention rate. During the 2018–2019 period, mean annual chloride application rates in the major watershed increased from 363000 kg/year (2012–2017) to 479000 kg/year. This led to a net chloride accumulation (KB100 subwatershed: 339000 kg; KB150 subwatershed: 188000 kg) and increased groundwater chloride concentrations in the fen. Chloride outflux from these subwatersheds was primarily driven by discharge. We found that the relationship between wetland percent cover and chloride retention is complex. Although the percent wetland cover is greater in the KB100 main wetland region compared to the KB150 subwatershed, high precipitation in 2018 resulted in similar chloride retention efficiencies (~26%). During the drier year (2019), chloride retention was higher in the wetland region due to its gentle slopes which promote water accumulation and consequently higher evaporation rates which lowers discharge and chloride outfluxes. The chloride steady-state concentration analysis also suggests that there is potential for chloride accumulation to continue because the watershed has not yet reached steady-state chloride concentrations. Without major modifications to salting practices, chloride concentrations will continue increasing and potentially promote the re-growth of invasives (Phragmites) and continued growth of salt tolerant species (Typha angustifolia/xglauca) that diminish plant diversity. [ABSTRACT FROM AUTHOR]

Understanding the global variation of plant strategies is essential for unravelling eco-evolutionary processes and ecosystem functions. Variation in ten fundamental aboveground and fine-root traits is summarised in four dimensions, the first of which relates to aboveground plant size. However, there is no consensus about how root size fits within this scheme. Here, we add rooting depth and lateral spread, compiling a set of twelve key traits that define the fundamental investments of plants in growth, reproduction, and survival. We examine whether the inclusion of root size alters the dimensionality and structure of trait correlations defining plant functional strategies. Our results show that including root size traits does not alter the fundamental structure and dimensionality of the plant functional space, regardless of trait completeness and phylogenetic relatedness. Plant size defines a single continuum of allometric investments at the global scale, independent from leaf and root economic strategies. Plants show diverse strategies for growth, reproduction, and survival, shaped by key aboveground and root traits. This study finds that adding root size traits does not change the global structure of plant strategies, confirming that plant size follows a unified continuum of allometric investment. [ABSTRACT FROM AUTHOR]

In urban areas with dense populations and high water demands, effective management of water resources is crucial for sustainable development. It includes optimizing water usage and recycling wastewater to balance supply and demand. Urban rivers, which now carry sewage year-round due to increased urban water consumption, are increasingly used for irrigation in peri-urban regions. This study aims to assess the suitability of an urban stream for irrigation compared to catchment groundwater, using hydrochemical parameters to evaluate water quality indices. Analysis of major ion distribution from upstream to downstream reveals a significant increase of TDS (r2 = 0.65; p < 0.001) in the surface water and a decrease (r2 = 0.93; p < 0.001) in groundwater samples. The calculated Weighted Arithmetic-Water Quality Index (WA-WQI) indicates that around 85% and 75% of surface water and groundwater samples from the Musi river are classified as very poor to unsuitable for any use, highlighting critical pollution levels. Based on irrigation suitability indices, only 16% of the surface water samples and 60% of the groundwater samples are suitable for irrigation. The nitrate concentration increased from less than 10 mg l−1 in the upstream region to over 100 mg l−1 in the urban stretch. Nitrogen-Phosphate-Potassium (NPK) ratios across the basin are exceptionally higher, representing crops irrigated using the Musi river water might not require fertilizer applications. The adoption of fertilizer application concerning supplied water hydrochemistry, particularly the NPK ratio, might limit the excess usage of fertilizer and benefit farmers. Additionally, this practice may also limits the excess input of nitrate to the groundwater in the Musi river basin. [ABSTRACT FROM AUTHOR]

Plant diversity is the basis for human survival and development, directly affecting the function and stability of urban ecosystems. Its distribution pattern and causes have been a central issue in ecological and landscape gardening research. Rapid urbanization in Zhengzhou City has led to the fragmentation of urban green spaces and damage to ecosystems, seriously affecting urban biodiversity conservation. Understanding the distribution pattern of plant diversity in the region and its relationship with environmental factors is crucial for maintaining and enhancing urban plant diversity. Plant data from 178 sample plots in the built-up area of Zhengzhou City were collected and combined with environmental factors, and the characteristics of plant diversity, richness patterns, and their main environmental explanations in Zhengzhou City were explored. Results showed that there were 596 plant species belonging to 357 genera and 110 families in the study area. There were five dominant families and four dominant genera. Four distinct spatial patterns of plant diversity were identified along the urban–rural gradient. Urbanization factors such as GDP per capita, house prices, and imperviousness within 500 m from the patch significantly influenced plant diversity. There was an imbalance between the spatial pattern of plant diversity and application of urban landscape greening in Zhengzhou City. Future studies should focus on the application of native plants, curb plant homogenization, and reduce anthropogenic interference, which are conducive to protecting and enhancing urban plant diversity. These results can provide a basis for understanding the distribution pattern and influence mechanism of urbanization factors on plant diversity and serve as a reference for policymakers and planners of plant diversity conservation in Zhengzhou City. [ABSTRACT FROM AUTHOR]

Human activities can increase sediment delivery to streams, changing the composition, distribution, and abundance of stream aquatic life. Few U.S. states have numeric water quality standards for streambed sediment under the Clean Water Act, so managers often need to develop local application-specific benchmarks. This study developed stream surface fine sediment <2 mm (sand and fines, SF) and macroinvertebrate fine sediment biotic index (FSBI) benchmarks and an application framework to test for sediment-induced macroinvertebrate community composition changes in 1st–4th order Idaho streams. FSBI reference benchmarks were calculated as the 25th percentile FSBI value among reference sites within three ecoregion-based site classes. Two approaches were used to develop SF benchmarks. Quantile regression was used to define reach-specific SF benchmarks representing an upper bound value expected under reference conditions. In addition, logistic regression was used to predict SF values with 50% and 75% probability that FSBI is worse than reference within each stream order and site class. The strength of association between SF benchmarks and macroinvertebrate community condition was evaluated by calculating relative risk using multiple datasets and examining responses of multiple macroinvertebrate indicators to SF benchmark status. SF reference benchmarks generally had stronger associations with poor macroinvertebrate condition than SF stressor-response benchmarks. Across datasets and macroinvertebrate indicators, poor macroinvertebrate condition was 1.8–3 times more likely when SF reference benchmarks were exceeded than when achieved. We propose rating the strength of evidence for a surface fine sediment-induced macroinvertebrate community composition change at the sample event scale as 'unlikely' if both SF and FSBI reference benchmarks are achieved, having 'mixed evidence' if only one reference benchmark is achieved, and 'likely' if both reference benchmarks are not achieved. We recommend combining ratings with other relevant data in a weight-of-evidence approach to assess if sediment impairs aquatic life. [ABSTRACT FROM AUTHOR]

Purpose: The 3D U-Net deep neural network structure is widely employed for dose prediction in radiotherapy. However, the attention to the network depth and its impact on the accuracy and robustness of dose prediction remains inadequate. Methods: 92 cervical cancer patients who underwent Volumetric Modulated Arc Therapy (VMAT) are geometrically augmented to investigate the effects of network depth on dose prediction by training and testing three different 3D UNet structures with depths of 3, 4, and 5. Results: For planning target volume (PTV), the differences between predicted and true values of D98, D99, and Homogeneity were statistically 1.00 ± 0.23, 0.32 ± 0.72, and -0.02 ± 0.02 for the model with a depth of 5, respectively. Compared to the other two models, these parameters were also better. For most of the organs at risk, the mean and maximum differences between the predicted values and the true values for the model with a depth of 5 were better than for the other two models. Conclusions: The results reveal that the network model with a depth of 5 exhibits superior performance, albeit at the expense of the longest training time and maximum computational memory in the three models. A small server with two NVIDIA GeForce RTX 3090 GPUs with 24 G of memory was employed for this training. For the 3D U-Net model with a depth of more than 5 cannot be supported due to insufficient training memory, the 3D U-Net neural network with a depth of 5 is the commonly used and optimal choice for small servers. [ABSTRACT FROM AUTHOR]

The distribution of the ecologically damaging invasive Cuban Treefrog (CTF, Anura, Hylidae, Osteopilus septentrionalis) in the USA is documented primarily by users of invasive species applications (apps) such as the Early Detection and Distribution Mapping System (EDDMapS). The purpose of this case study was to investigate spatial and temporal patterns in EDDMapS’s CTF records from Florida, USA. With the accessibility of geolocated records and machine learning algorithms, predicted species distribution models (SDMs) need to be revisited to explore their accuracy as new records become available. Utilizing the machine learning TreeNet® Classification algorithm, I constructed an SDM from records uploaded in 1999–2020, mean monthly temperature and rainfall patterns from 1999–2020, 2020 United States census data, and proximity to water and residential land cover types. Of the 1,042 geolocated records, the mean annual number of entries was more than 30 times greater from 2010–2020 than years prior, indicating greater utilization of the app with time. Residential areas and wetland land cover categories represented 35.2%, and 29.8%, respectively, of the locations where the CTF had been recorded. The variables mean monthly temperature and minimum temperature during the coldest quarter contributed the greatest contribution to the model with predicted suitable areas primarily in southern Florida. Using 2021–2023 records to validate the SDM, 96.7% of the 398 geolocated records were associated with a relative occurrence index ≥ 0.80, indicating the model’s predicted suitable areas performed well. Regional programs that aim to train, mentor, and incentivize the public to report geolocated presence and absence observations with microhabitat descriptions would improve the accuracy of predicted suitable areas for invasive species whose records derive mainly from invasive species monitoring apps. [ABSTRACT FROM AUTHOR]

Lacustrine environments from Northern Patagonia are exposed to volcanic events from the Southern Volcanic Zone. Chironomid larvae are an important paleo-proxy because, in addition to their environmental sensitivity, their chitinous cephalic capsules are well preserved in lacustrine sediments, allowing their recovery and identification. We analysed the effects of a recent volcanic eruption (Puyehue-Cordón Caulle Volcanic Complex 2011) on the chironomid community based on their cephalic remains accumulated following the ash deposition process. Two pulses of ash deposition were distinguished: a first stage comprising the immediate coarse ash fall and a delayed finer volcanic deposition. An abrupt decline in chironomid taxa and their densities were noted during the first coarse pulse, followed by an attempt of community recovery through the second finer pulse, characterised by main taxa turnover, observing an alternative community functional structure. Based on these results and comparing with past volcanic depositions, we observed different chironomid responses according to their particular ecological habits, and we noted possible percolation effects, mainly in coarse tephras, and probably a delayed record of very low abundance taxa. Our results suggest caution in analysing chironomid assemblages within and adjacent to tephra deposition as local volcanic eruption could affect chironomid community with possible consequences on paleoreconstructions. [ABSTRACT FROM AUTHOR]

Diabetes Mellitus (DM) is on the rise making it a major concern for global health. DM can be classified into type 1 or type 2, and both can lead to changes in brain metabolites. These can result in serious complications like cognitive decline, particularly if not managed properly by diabetic patients. Magnetic Resonance Spectroscopy (MRS) is a non-invasive technique that allows us to study the brain metabolite levels. The present review utilises available Magnetic Resonance Imaging (MRI) data to understand how brain metabolites are affected in both type 1 and type 2 diabetes (T2DM). Research shows that in individuals with diabetes, there are changes in important brain chemicals such as creatine (Cr), N-Acetyl Aspartate (NAA), Myo-Inositol (MI), choline (Cho), glutamate, and glutamine. A consistent finding across multiple studies showed a reduction in NAA levels, which is a key indicator of brain neuron health. This suggests that diabetes negatively impacts the function of neurons in the brain. Changes were seen in other metabolites indicating potential disruptions in energy regulation and membrane function. This review concludes that alterations in brain metabolites as measured using MRS, could serve as a non-invasive biomarker for tracking the progression of DM and its related complications. [ABSTRACT FROM AUTHOR]

Background: While many factors have been examined, male gender and older age at multiple sclerosis onset are among few variables consistently associated with increased disability. Interestingly, the association between onset age and disability may not be linear with some data suggesting a faster rate of accumulation of disability in patients aged more than 30 years at onset., Objective: Explore the relationship between onset age and disability., Methods: We studied 500 MS patients grouped by cut-offs in onset age. Disability was assessed using Multiple Sclerosis Severity Scale (MSSS) and, a model based on time to reach an Extended Disability Severity Score (EDSS) (progression model). Data were analyzed using linear and logistic regression., Results: The association between disability (assessed by both MSSS and the progression model) and onset age was different in patients whose MS onset occurred after an age band of 30-35 years. Before this age range, changing age was not associated with changes in disability while during and after this age range, disability was increased., Conclusion: We found a significant change in the relationship between disability and onset age after about 31 years supporting the idea that while onset age does not define a sharp cut-off, it can help define subgroups of patients with differing rates of accumulation of disability., (Copyright © 2014 Elsevier B.V. All rights reserved.)

Factors controlling proliferation and differentiation are crucial in advancement of neural cell-based experimental neurodegenerative therapies. In this regard, nicotinamide has been shown to determine the fate of neural cells, enhance neuralization, and influence DNA repair and apoptosis. This study investigated whether the biologically active vitamin B3 metabolite, nicotinamide, could direct the differentiation of mouse embryonic stem cells, cultured as monolayers, into neurons at either early or late stages of development. Interestingly, we observed a dose-responsive increase in the percentage of neurons when nicotinamide was added at early stages to the cells undergoing differentiation (days 0-7). Nicotinamide (10 mM) had a significant effect on neuronal differentiation, increasing the βIII-tubulin-positive neuronal population and concomitantly decreasing the total number of cells in culture, measured by quantification of 4',6-diamidino-2-phenylindole (DAPI)-positive cells. Nicotinamide added between days 7 and 14 had no effect on neuronal induction. High levels of nicotinamide (20 mM) induced cytotoxicity and cell death. Current work is focusing on elucidating the mechanism(s) mediating neural specification by nicotinamide--that is, induction of cell-cycle exit and/or selective apoptosis in non-neural populations. Preliminary data suggest a reduction in the proportion of proliferating cells in nicotinamide-treated cultures--that is, nicotinamide enhances cell-cycle exit, thereby promoting neuronal differentiation. Future work will focus on evaluating the effect of nicotinamide on the differentiation of midbrain dopamine neurons, towards a therapy for Parkinson's disease.

Background: The extended disability severity scale (EDSS) is clinically useful in assessing disability in multiple sclerosis (MS) patients. It is also being used in studies to determine how genes and environment influence disability. However, since it has a complex relationship with functional scores and mobility and is strongly determined by disease duration its use can be limiting., Objective: Study associations of variables with progression described by time from disease onset until EDSS., Methods: We used a variable based on below/above median time from MS onset to reach a single EDSS value to define slow or fast progression. We compared patient categorization using this variable and MSSS, and in 533 patients (EDSS 1-8) and 242 of these patients with EDSS1-4, studied associations with skin type, gender, ultraviolet radiation and MC1R Asp294His., Results: Classifying patients into quartiles of slow/fast progression showed mean MSSS increased with faster progression (p<0.001). For EDSS 1-8: MSSS, late onset age and childhood sunburning were associated with fast and MC1R CG/GG(294) with slow progression. Combinations of skin type (1/2 or 3/4) with childhood weekend exposure (< or ≥median) or sunburning (yes/no) were not associated with progression. However, in patients with EDSS1-4, relative to other combinations, those with no sunburning history and types 1/2 demonstrated slow progression (odds ratio=0.15, 95% CI=0.04, 0.57)., Conclusion: This method, though a pilot, allows study of associations of variables with EDSS. It is based on local patients and could substitute for MSSS. In patients with EDSS1-4 but not 1-8, skin type 1/2 with no history of childhood sunburning was associated with slow progression. This is compatible with the view that disability develops through a first stage dependent on inflammation., (Copyright © 2012. Published by Elsevier B.V.)

Background: Self-efficacy concerns the individual's belief that he or she is capable of performing a certain task and producing a desired effect, i.e. it reflects the person's perceptions of their capability for specific tasks, as distinct from their actual ability. Self-efficacy has been shown to influence motivation, psychological well-being, adherence with treatment regimes and quality of life in multiple sclerosis and other conditions., Objective: To develop a unidimensional scale of MS self-efficacy with robust psychometric properties, suitable for patient self report., Methods: A questionnaire pack covering three MS self-efficacy scales, the Dispositional Resilience Scale and demographic data was posted to MS patients from two MS databases. Data underwent Rasch analysis., Results: Response rate was 309/600 (51.5%). None of the existing MS self-efficacy scales were unidimensional. A new 12-item scale, created by combining items from our two scales, was shown to fit the Rasch model, was unidimensional, and invariant for gender, education and disease duration., Conclusion: The Unidimensional Self-Efficacy scale for MS (USE-MS) provides a simple summated scale for an ordinal estimate of a persons' self efficacy. A transformation to interval scaling is available for use in the calculation of change scores and effect sizes.

Assessing the biodiversity of macroinvertebrate fauna in freshwater ecosystems is an essential component of both basic ecological inquiry and applied ecological assessments. Aspects of taxonomic diversity and composition in freshwater communities are widely used to quantify water quality and measure the efficacy of remediation and restoration efforts. The accuracy and precision of biodiversity assessments based on standard morphological identifications are often limited by taxonomic resolution and sample size. Morphologically based identifications are laborious and costly, significantly constraining the sample sizes that can be processed. We suggest that the development of an assay platform based on DNA signatures will increase the precision and ease of quantifying biodiversity in freshwater ecosystems. Advances in this area will be particularly relevant for benthic and planktonic invertebrates, which are often monitored by regulatory agencies. Adopting a genetic assessment platform will alleviate some of the current limitations to biodiversity assessment strategies. We discuss the benefits and challenges associated with DNA-based assessments and the methods that are currently available. As recent advances in microarray and next-generation sequencing technologies will facilitate a transition to DNA-based assessment approaches, future research efforts should focus on methods for data collection, assay platform development, establishing linkages between DNA signatures and well-resolved taxonomies, and bioinformatics.

Background: Multiple sclerosis outcome may be influenced by ultraviolet radiation and vitamin D synthesis, suggesting skin type and genes determining this phenotype are candidates for disability. However, though associations between melanocortin 1 receptor (MC1R) single nucleotide polymorphisms and disability are reported, some data are incompatible with their expected influence on skin type., Objective: Determine which MC1R single nucleotide polymorphisms affect disability and establish if ultraviolet radiation modifies such associations., Methods: We studied using linear regression in 525 cases, associations of the Multiple Sclerosis Severity Score (MSSS) with skin type, gender, ultraviolet radiation exposure and six MC1R single nucleotide polymorphisms (rs1805005, rs1805006, rs2228479, rs1805007, rs1805008, rs1805009)., Results: CG(294) with GG(294) genotypes (rs1805009) (coefficient = -1.44, 95% CI -2.30, -0.59, mean MSSS +/- SD = 4.33 +/- 2.87) and AC(84) (rs1805006) (coefficient = 1.62, 95% CI 0.17, 3.06, mean MSSS = 7.62 +/- 2.43) were associated with MSSS. Associations with Asp294His were found in those with skin types 1/2 and 3/4, and cases stratified by ultraviolet radiation exposure. However, they were seen only in cases with a history of childhood sunburn and not in those without sunburn. We found no significant associations between exposure parameters and MSSS., Conclusions: Multiple sclerosis outcome is influenced by interactions between host response to ultraviolet radiation and MC1R single nucleotide polymorphisms. The influence of the single nucleotide polymorphisms appears distinct from their association with skin type.

Ultraviolet radiation (UVR) may contribute to multiple sclerosis (MS) outcome by a mechanism involving vitamin D and the vitamin D receptor (VDR). In 512 patients with MS duration of 10 or more years, we studied the association of VDR single nucleotide polymorphisms (A/G(1229), C/G(3444), G/A(3944), CC(20965), CC(30056), F/f(30875), C/T(48200), T/t(65013)) with outcome or disability. ff(30875) frequency was lower in cases with EDSS > or = 6.0 than with scores < 6.0 (odds ratio = 0.38, 95% CI = 0.20-0.70). The association of ff(30875) with outcome was not mediated by cumulative exposure to UVR as assessed by questionnaire; low exposure (odds ratio = 0.42, 95% CI = 0.14-1.34) and high exposure (odds ratio = 0.34, 95% CI = 0.16-0.73).

Ecological surveys provide the basic information needed to estimate differences in species richness among assemblages. Comparable estimates of the differences in richness between assemblages require equal mean species detectabilities across assemblages. However, mean species detectabilities are often unknown, typically low, and potentially different from one assemblage to another. As a result, inferences regarding differences in species richness among assemblages can be biased. We evaluated how well three methods used to produce comparable estimates of species richness achieved equal mean species detectabilities across diverse assemblages: rarefaction, statistical estimators, and standardization of sampling effort on mean taxonomic similarity among replicate samples (MRS). We used simulated assemblages to mimic a wide range of species-occurrence distributions and species richness to compare the performance of these three methods. Inferences regarding differences in species richness based on rarefaction were highly biased when richness estimates were compared among assemblages with distinctly different species-occurrence distributions. Statistical estimators only marginally reduced this bias. Standardization on MRS yielded the most comparable estimates of differences in species richness. These findings have important implications for our understanding of species-richness patterns, inferences drawn from biological monitoring data, and planning for biodiversity conservation.

Encephalitis is uncommon but is a neurological emergency which must be considered in a patient presenting with altered consciousness. Encephalitis is a diffuse inflammatory process of the brain parenchyma associated with evidence of brain dysfunction. The presentation of encephalitis can be acute or chronic. The aetiology of encephalitis can be broadly divided into two major subtypes. (1) Infection-related encephalitis which is a direct consequence of pathogenic viral, bacterial or parasitic agents. Herpes simplex virus (HSV) and varicella-zoster virus (VZV) are the most common cause of acute infectious encephalitis. (2) Autoimmune-mediated encephalitis which is mediated by an aberrant immune response. This can be triggered by a recent viral infection or vaccination. An example of this would be acute disseminated encephalitis (ADEM). This article will focus on the medical management of acute encephalitis. This will involve an extensive overview of the literature reviewing the diagnosis, investigation and treatment of acute viral encephalitis, ADEM and acute haemorrhagic leukoencephalopathy (AHLE). Encephalitis can also present chronically, and some of the different types of chronic encephalitis will be discussed.

Recent studies suggest ultraviolet radiation (UVR)/vitamin D is protective against the development of multiple sclerosis (MS). We determined if outcome in MS is associated with the surrogate for host pigmentation, skin type, and parameters of UVR exposure. We used a validated questionnaire to determine skin type and UVR exposure during childhood (0-16 years), and early adult life (17-40 years), in 448 Caucasians with MS. Outcome was assessed using the Kurtzke Expanded Disability Status Score (EDSS) and Multiple Sclerosis Severity Scale (MSSS). We studied the association of skin type and exposure with dichotomized values of EDSS (< and >or=6) and MSSS (continuous variable) using logistic and linear regression analyses, respectively. Sex, onset age and MS duration were significantly associated with outcome in all patients. In 169 females with established disease (>or=10 years), sun sensitive skin types 1 and 2 were associated with reduced risk of EDSS >or=6 (odds ratio =0.50; 95% CI = 0.26-0.97), and higher MSSS values (coefficient = -0.86; 95% CI = -1.67 to -0.05). Parameters of UVR exposure were not significantly associated with outcome. These preliminary data show an association between skin type and disability in female MS patients. They are compatible with independent studies suggesting that exposure mediates MS pathogenesis via vitamin D. Further studies are required to properly assess these potentially important findings.