3,388 research outputs found
Applications of stable water and carbon isotopes in watershed research: Weathering, carbon cycling, and water balances
Research on rivers has traditionally involved concentration and flux measurements to better understand
weathering, transport and cycling of materials from land to ocean. As a relatively new tool, stable isotope
measurements complement this type of research by providing an extra label to characterize origin of the
transportedmaterial, its transfer mechanisms, and natural versus anthropogenic influences. These new stable
isotope techniques are scalable across a wide range of geographic and temporal scales. This review focuses on
three aspects of hydrological and geochemical river research that are of prime importance to the policy issues
of climate change and include utilization of stable water and carbon isotopes: (i) silicate and carbonate
weathering in river basins, (ii) the riverine carbon and oxygen cycles, and (iii) water balances at the
catchment scale. Most studies at watershed scales currently focus on water and carbon balances but future
applications hold promise to integrate sediment fluxes and turnover, ground and surface water interactions,
as well as the understanding of contaminant sources and their effects in river systems
How can we improve management of syncope in the Emergency Department?
Syncope is a common and challenging presenting complaint to the Emergency Department (ED). Despite substantial research efforts, there is still considerable uncertainty about the optimal ED management of syncope. There is continued interest among clinicians and researchers in improving diagnostic algorithms and optimizing resource utilization. In this paper, we discuss 4 strategies to improve the emergency care of syncope patients: (1) Development of accurate and consistent risk-stratification, (2) Increased use of syncope observation protocols, (3) Evaluation of a discharge with ambulatory monitoring pathway, (4) Use of shared decision-making for disposition decisions. Since current risk-stratification tools have fallen short with regard to subsequent validation and implementation into clinical practice, we outline key factors for future risk-stratification research. We propose that observation units have the potential to safely decrease length-of-stay and hospital costs for hemodynamically stable, intermediate risk patients without adversely affecting clinical outcomes. For appropriate patients with a negative ED evaluation, we recommend consideration of direct discharge, with ambulatory monitoring and expedited follow-up, as a means of decreasing costs and reducing iatrogenic harms. Finally, we advocate for the use of shared decision-making regarding the ultimate disposition of select, intermediate risk patients who have not had a serious condition revealed in the ED. If properly implemented, these four strategies could significantly improve the care of ED syncope patients by helping clinicians identify truly high-risk patients, decreasing unnecessary hospitalizations, and increasing patient satisfaction.
Protease inhibitors prevent plasminogen-mediated, but not pemphigus vulgaris-induced, acantholysis in human epidermis
Pemphigus is an autoimmune blistering disease of the skin and mucous membranes. It is caused by autoantibodies directed against desmosomes, which are the principal adhesion structures between epidermal keratinocytes. Binding of autoantibodies leads to the destruction of desmosomes resulting in the loss of cell-cell adhesion (acantholysis) and epidermal blisters. The plasminogen activator system has been implicated as a proteolytic effector in pemphigus. We have tested inhibitors of the plasminogen activator system with regard to their potential to prevent pemphigus-induced cutaneous pathology. In a human split skin culture system, IgG preparations of sera from pemphigus vulgaris patients caused histopathologic changes (acantholysis) similar to those observed in the original pemphigus disease. All inhibitors that were tested (active site inhibitors directed against uPA, tPA, and/or plasmin; antibodies neutralizing the enzymatic activity of uPA or tPA; substances interfering with the binding of uPA to its specific cell surface receptor uPAR) failed to prevent pemphigus vulgaris IgG-mediated acantholysis. Plasminogen-mediated acantholysis, however, was effectively antagonized by the synthetic active site serine protease inhibitor WX-UK1 or by p-aminomethylbenzoic acid. Our data argue against applying anti-plasminogen activator/anti-plasmin strategies in the management of pemphigus
The Psychosocial Consequences of Sports Participation for Individuals with Severe Mental Illness: A Metasynthesis Review
The purpose of the current metasynthesis review was to explore the psychosocial benefits of sport and psychosocial factors which impact on sports participation for individuals with severe mental illness. AMED, CINAHL Plus, Medline, EMBASE, ProQuest Nursing & Allied Health Source, and Science Citation Index were searched from inception until January 2014. Articles included use qualitative methods to examine the psychosocial effects of sports participation in people with severe mental illness. Methodological quality was assessed using the Consolidated Criteria for Reporting Qualitative Studies and a case study tool. Included studies were analysed within a metasynthesis approach. Eight articles involving 56 patients met the inclusion criteria. The results identified the broader and direct psychosocial benefits of sport. Sport provided a ?normal? environment and interactions that were not associated with an individual?s mental illness. Sport provided individuals with a sense of meaning, purpose, belonging, identity, and achievement. Other findings are discussed. Direct psychosocial benefits are a consequence of sports participation for the vast majority of individuals with severe mental illness. Further to this, sports participation was associated with a reduction in social isolation and an increase in social confidence, autonomy, and independence
Heart rate variability in association with frequent use of household sprays and scented products in SAPALDIA
Background: Household cleaning products are associated with adverse respiratory health outcomes, but the cardiovascular health effects are largely unknown.Objective: We determined if long-term use of household sprays and scented products at home was associated with reduced heart rate variability (HRV), a marker of autonomic cardiac dysfunction.Methods: We recorded 24-hr electrocardiograms in a cross-sectional survey of 581 Swiss adults, 1, 1-3, or 4-7 days/week, unexposed (reference)] of using cleaning sprays, air freshening sprays, and scented products.Results: Decreases in 24-hr SDNN and TP were observed with frequent use of all product types, but the strongest reductions were associated with air freshening sprays. Compared with unexposed participants, we found that using air freshening sprays 4-7 days/week was associated with 11% [95% confidence interval (CI): -20%, -2%] and 29% (95% CI: -46%, -8%) decreases in 24-hr SDNN and TP, respectively. Inverse associations of 24-SDNN and TP with increased use of cleaning sprays, air freshening sprays, and scented products were observed mainly in participants with obstructive lung disease (p > 0.05 for interactions).Conclusions: In predominantly older adult women, long-term frequent use of household spray and scented products was associated with reduced HRV, which suggests an increased risk of cardiovascular health hazards. People with preexisting pulmonary conditions may be more susceptibl
A software architecture for mechanism-based social systems modelling in agent-based simulation models
This paper introduces the MBSSM (Mechanism-Based Social Systems Modelling) software architecture that is designed for expressing mechanisms of social theories with individual behaviour components in a unified way and implementing these mechanisms in an agent-based simulation model. The MBSSM architecture is based on a middle-range theory approach most recently expounded by analytical sociology and is designed in the object-oriented programming paradigm with Unified Modelling Language diagrams. This paper presents two worked examples of using the architecture for modelling individual behaviour mechanisms that give rise to the dynamics of population-level alcohol use: a single-theory model of norm theory and a multi-theory model that combines norm theory with role theory. The MBSSM architecture provides a computational environment within which theories based on social mechanisms can be represented, compared, and integrated. The architecture plays a fundamental enabling role within a wider simulation model-based framework of abductive reasoning in which families of theories are tested for their ability to explain concrete social phenomena
Multiobjective genetic programming can improve the explanatory capabilities of mechanism-based models of social systems
The generative approach to social science, in which agent-based simulations (or other complex systems models) are executed to reproduce a known social phenomenon, is an important tool for realist explanation. However, a generative model, when suitably calibrated and validated using empirical data, represents just one viable candidate set of entities and mechanisms. The model only partially addresses the needs of an abductive reasoning process - specifically it does not provide insight into other viable sets of entities or mechanisms, nor suggest which of these are fundamentally constitutive for the phenomenon to exist. In this
paper, we propose a new model discovery framework that more fully captures the needs of realist explanation. The framework exploits the implicit ontology of an existing human-built
generative model to propose and test a plurality of new candidate model structures. Genetic programming is used to automate this search process. A multi-objective approach is used, which enables multiple perspectives on the value of any particular generative model - such as goodness-of-fit, parsimony, and interpretability - to be represented simultaneously. We demonstrate this new framework using a complex systems modeling case study of change and stasis in societal alcohol use patterns in the US over the period 1980-2010. The framework is successful in identifying three competing explanations of these alcohol use patterns, using novel integrations of social role theory not previously considered by the human modeler. Practitioners in complex systems modeling should use model discovery to improve the explanatory utility of the generative approach to realist social science
Searching for the Annual Modulation of Dark Matter signal with the GENIUS-TF experiment
The annual modulation of the recoil spectrum observed in an underground
detector is well known as the main signature of a possible WIMP signal. The
GENIUS-TF experiment, under construction in the Gran Sasso National Laboratory,
can search for the annual modulation of the Dark Matter signal using 40 kg of
naked-Ge detectors in liquid nitrogen. Starting from a set of data simulated
under the hypothesis of modulation and using different methods, we show the
potential of GENIUS-TF for extracting the modulated signal and the expected
WIMP mass and WIMP cross section.Comment: In press, Nuclear Instruments and Methods in Physics Research Section
A: Accelerators, Spectrometers, Detectors and Associated Equipment (2003) and
in Proc. of IDM2002, York Minster, England, 2-6 September, 2002, World
Scientific 200
The normative underpinnings of population-level alcohol use: An individual-level simulation model
Background. By defining what is ânormal,â appropriate, expected, and unacceptable, social norms shape human behavior. However, the individual-level mechanisms through which social norms impact population-level trends in health-relevant behaviors are not well understood. Aims. To test the ability of social norms mechanisms to predict changes in population-level drinking patterns. Method. An individual-level model was developed to simulate dynamic normative mechanisms and behavioral rules underlying drinking behavior over time. The model encompassed descriptive and injunctive drinking norms and their impact on frequency and quantity of alcohol use. A microsynthesis initialized in 1979 was used as a demographically representative synthetic U.S. population. Three experiments were performed in order to test the modelled normative mechanisms. Results. Overall, the experiments showed limited influence of normative interventions on population-level alcohol use. An increase in the desire to drink led to the most meaningful changes in the populationâs drinking behavior. The findings of the experiments underline the importance of autonomy, that is, the degree to which an individual is susceptible to normative influence. Conclusion. The model was able to predict theoretically plausible changes in drinking patterns at the population level through the impact of social mechanisms. Future applications of the model could be used to plan norms interventions pertaining to alcohol use as well as other health behaviors
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