118 research outputs found
Weaker landâclimate feedbacks from nutrient uptake during photosynthesis-inactive periods
Terrestrial carbonâclimate feedbacks depend on two large and opposing fluxesâsoil organic matter decomposition and photosynthesisâthat are tightly regulated by nutrients . Earth system models (ESMs) participating in the Coupled Model Intercomparison Project Phase 5 represented nutrient dynamics poorly , rendering predictions of twenty-first century carbonâclimate feedbacks highly uncertain. Here, we use a new land model to quantify the effects of observed plant nutrient uptake mechanisms missing in most other ESMs. In particular, we estimate the global role of root nutrient competition with microbes and abiotic processes during periods without photosynthesis. Nitrogen and phosphorus uptake during these periods account for 45 and 43%, respectively, of annual uptake, with large latitudinal variation. Globally, night-time nutrient uptake dominates this signal. Simulations show that ignoring this plant uptake, as is done when applying an instantaneous relative demand approach, leads to large positive biases in annual nitrogen leaching (96%) and N O emissions (44%). This N O emission bias has a GWP equivalent of ~2.4 PgCO yr , which is substantial compared to the current terrestrial CO sink. Such large biases will lead to predictions of overly open terrestrial nutrient cycles and lower carbon sequestration capacity. Both factors imply over-prediction of positive terrestrial feedbacks with climate in current ESMs. 1,2 1,3 â1 2 2 2
Trophic Shifts of a Generalist Consumer in Response to Resource Pulses
Trophic shifts of generalist consumers can have broad food-web and biodiversity consequences through altered trophic flows and vertical diversity. Previous studies have used trophic shifts as indicators of food-web responses to perturbations, such as species invasion, and spatial or temporal subsidies. Resource pulses, as a form of temporal subsidies, have been found to be quite common among various ecosystems, affecting organisms at multiple trophic levels. Although diet switching of generalist consumers in response to resource pulses is well documented, few studies have examined if the switch involves trophic shifts, and if so, the directions and magnitudes of the shifts. In this study, we used stable carbon and nitrogen isotopes with a Bayesian multi-source mixing model to estimate proportional contributions of three trophic groups (i.e. producer, consumer, and fungus-detritivore) to the diets of the White-footed mouse (Peromyscus leucopus) receiving an artificial seed pulse or a naturally-occurring cicadas pulse. Our results demonstrated that resource pulses can drive trophic shifts in the mice. Specifically, the producer contribution to the mouse diets was increased by 32% with the seed pulse at both sites examined. The consumer contribution to the mouse diets was also increased by 29% with the cicadas pulse in one of the two grids examined. However, the pattern was reversed in the second grid, with a 13% decrease in the consumer contribution with the cicadas pulse. These findings suggest that generalist consumers may play different functional roles in food webs under perturbations of resource pulses. This study provides one of the few highly quantitative descriptions on dietary and trophic shifts of a key consumer in forest food webs, which may help future studies to form specific predictions on changes in trophic interactions following resource pulses
Distress and quality of life characteristics associated with seeking surgical treatment for stress urinary incontinence
<p>Abstract</p> <p>Background</p> <p>Current research focuses on three variables in evaluating the impact of stress urinary incontinence (SUI) on daily living: severity of incontinence, distress or bother resulting from incontinence, and effect on health related quality of life (HRQoL). Understanding the impact of these variables is important as they are the driving force behind women seeking surgical treatment. Given the importance of HRQoL in determining need for treatment, as well as evaluating treatment success, this review provides an assessment of the degree to which HRQoL is impaired in women seeking surgical treatment.</p> <p>Methods</p> <p>PubMed searches for the terms "quality of life and distress and urinary incontinence" and "quality of life and bother and urinary incontinence" were performed with limits of English, human and female subjects through May 2008. All studies using validated instruments were included. No time limit was placed on the search.</p> <p>Results</p> <p>Of 178 articles retrieved, 21 met the inclusion criteria, and 17 reported methods of scoring. The studies used the Urogenital Distress Inventory (UDI) and the Incontinence Impact Questionnaire (IIQ). Wide ranges of mean and individual levels of severity of symptoms, UDI and IIQ scores were seen among women seeking surgical treatment. Fourteen studies reported baseline and post-surgical treatment distress and QoL data. Statistically significant improvements between baseline and post-surgical UDI and IIQ scores were reported in 12 studies. Reported cure rates ranged from 46% to 97%. Satisfaction with the procedure was reported in 4 studies and ranged from 84% to 91%. A minority of studies reported the relationship between reduction in symptoms and change in HRQoL.</p> <p>Conclusion</p> <p>HRQoL is the main reason women seek surgical treatment for incontinence and surgical treatment leads to a significant improvement in mean HRQoL scores. Assessment of HRQoL has proved less useful in identifying why individual women seek treatment for incontinence. Preliminary work has begun to characterize the interaction between severity of symptoms, distress or bother resulting from these urinary symptoms, impact on HRQoL, and treatment seeking behavior, but further research is needed. Greater standardization in the reporting of results of distress or bother and HRQoL would allow for comparison across studies.</p
Distress and quality of life characteristics associated with seeking surgical treatment for stress urinary incontinence
<p>Abstract</p> <p>Background</p> <p>Current research focuses on three variables in evaluating the impact of stress urinary incontinence (SUI) on daily living: severity of incontinence, distress or bother resulting from incontinence, and effect on health related quality of life (HRQoL). Understanding the impact of these variables is important as they are the driving force behind women seeking surgical treatment. Given the importance of HRQoL in determining need for treatment, as well as evaluating treatment success, this review provides an assessment of the degree to which HRQoL is impaired in women seeking surgical treatment.</p> <p>Methods</p> <p>PubMed searches for the terms "quality of life and distress and urinary incontinence" and "quality of life and bother and urinary incontinence" were performed with limits of English, human and female subjects through May 2008. All studies using validated instruments were included. No time limit was placed on the search.</p> <p>Results</p> <p>Of 178 articles retrieved, 21 met the inclusion criteria, and 17 reported methods of scoring. The studies used the Urogenital Distress Inventory (UDI) and the Incontinence Impact Questionnaire (IIQ). Wide ranges of mean and individual levels of severity of symptoms, UDI and IIQ scores were seen among women seeking surgical treatment. Fourteen studies reported baseline and post-surgical treatment distress and QoL data. Statistically significant improvements between baseline and post-surgical UDI and IIQ scores were reported in 12 studies. Reported cure rates ranged from 46% to 97%. Satisfaction with the procedure was reported in 4 studies and ranged from 84% to 91%. A minority of studies reported the relationship between reduction in symptoms and change in HRQoL.</p> <p>Conclusion</p> <p>HRQoL is the main reason women seek surgical treatment for incontinence and surgical treatment leads to a significant improvement in mean HRQoL scores. Assessment of HRQoL has proved less useful in identifying why individual women seek treatment for incontinence. Preliminary work has begun to characterize the interaction between severity of symptoms, distress or bother resulting from these urinary symptoms, impact on HRQoL, and treatment seeking behavior, but further research is needed. Greater standardization in the reporting of results of distress or bother and HRQoL would allow for comparison across studies.</p
Daphnia distribution in Andean Patagonian lakes: effect of low food quality and fish predation
The Gene Ontology resource: enriching a GOld mine
The Gene Ontology Consortium (GOC) provides the most comprehensive resource currently available for computable knowledge regarding the functions of genes and gene products. Here, we report the advances of the consortium over the past two years. The new GO-CAM annotation framework was notably improved, and we formalized the model with a computational schema to check and validate the rapidly increasing repository of 2838 GO-CAMs. In addition, we describe the impacts of several collaborations to refine GO and report a 10% increase in the number of GO annotations, a 25% increase in annotated gene products, and over 9,400 new scientific articles annotated. As the project matures, we continue our efforts to review older annotations in light of newer findings, and, to maintain consistency with other ontologies. As a result, 20 000 annotations derived from experimental data were reviewed, corresponding to 2.5% of experimental GO annotations. The website (http://geneontology.org) was redesigned for quick access to documentation, downloads and tools. To maintain an accurate resource and support traceability and reproducibility, we have made available a historical archive covering the past 15 years of GO data with a consistent format and file structure for both the ontology and annotations
Plants in aquatic ecosystems: current trends and future directions
Aquatic plants fulfil a wide range of ecological roles, and make a substantial contribution to the structure, function and service provision of aquatic ecosystems. Given their well-documented importance in aquatic ecosystems, research into aquatic plants continues to blossom. The 14th International Symposium on Aquatic Plants, held in Edinburgh in September 2015, brought together 120 delegates from 28 countries and six continents. This special issue of Hydrobiologia includes a select number of papers on aspects of aquatic plants, covering a wide range of species, systems and issues. In this paper we present an overview of current trends and future directions in aquatic plant research in the early 21st century. Our understanding of aquatic plant biology, the range of scientific issues being addressed and the range of techniques available to researchers have all arguably never been greater; however, substantial challenges exist to the conservation and management of both aquatic plants and the ecosystems in which they are found. The range of countries and continents represented by conference delegates and authors of papers in the special issue illustrate the global relevance of aquatic plant research in the early 21st century but also the many challenges that this burgeoning scientific discipline must address
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