3,602 research outputs found
Estimates of global terrestrial isoprene emissions using MEGAN (Model of Emissions of Gases and Aerosols from Nature)
Reactive gases and aerosols are produced by terrestrial ecosystems, processed within plant canopies, and can then be emitted into the above-canopy atmosphere. Estimates of the above-canopy fluxes are needed for quantitative earth system studies and assessments of past, present and future air quality and climate. The Model of Emissions of Gases and Aerosols from Nature (MEGAN) is described and used to quantify net terrestrial biosphere emission of isoprene into the atmosphere. MEGAN is designed for both global and regional emission modeling and has global coverage with ~1 km<sup>2</sup> spatial resolution. Field and laboratory investigations of the processes controlling isoprene emission are described and data available for model development and evaluation are summarized. The factors controlling isoprene emissions include biological, physical and chemical driving variables. MEGAN driving variables are derived from models and satellite and ground observations. Tropical broadleaf trees contribute almost half of the estimated global annual isoprene emission due to their relatively high emission factors and because they are often exposed to conditions that are conducive for isoprene emission. The remaining flux is primarily from shrubs which have a widespread distribution. The annual global isoprene emission estimated with MEGAN ranges from about 500 to 750 Tg isoprene (440 to 660 Tg carbon) depending on the driving variables which include temperature, solar radiation, Leaf Area Index, and plant functional type. The global annual isoprene emission estimated using the standard driving variables is ~600 Tg isoprene. Differences in driving variables result in emission estimates that differ by more than a factor of three for specific times and locations. It is difficult to evaluate isoprene emission estimates using the concentration distributions simulated using chemistry and transport models, due to the substantial uncertainties in other model components, but at least some global models produce reasonable results when using isoprene emission distributions similar to MEGAN estimates. In addition, comparison with isoprene emissions estimated from satellite formaldehyde observations indicates reasonable agreement. The sensitivity of isoprene emissions to earth system changes (e.g., climate and land-use) demonstrates the potential for large future changes in emissions. Using temperature distributions simulated by global climate models for year 2100, MEGAN estimates that isoprene emissions increase by more than a factor of two. This is considerably greater than previous estimates and additional observations are needed to evaluate and improve the methods used to predict future isoprene emissions
“If you can’t see a dilemma in this situation you should probably regard it as a warning”. A metasynthesis and theoretical modeling of general practitioners’ opioid prescription experiences in primary care.
Background: The prescribing of opioids has increased internationally in developed countries in recent decades within primary and secondary care.1 The majority of patients with chronic non-malignant pain (CNMP) are managed by their GP.2 Recent qualitative studies have examined the issue of opioid prescribing for chronic non-malignant pain (CNMP) from a GP viewpoint. Several factors have been reported to influence the prescribing of opioids for CNMP including aetiology of pain condition, co-morbidities, access to specialised care, history of drug abuse and professional scrutiny. We require a better understanding of problems GP’s face when making opioid prescribing decisions, interventions to provide better supports in the prescribing of opioids for CNMP. The aim of this study is to identify and synthesize the qualitative literature describing the factors influencing the nature and extent of opioid prescribing in CNMP in primary care. A theoretical model is then proposed which seeks to explain the relationship between factors influencing prescribing of opioids for CNMP by GPs. Methods: MEDLINE, Embase, PsychINFO, Cochrane Database, International Pharmaceutical Abstracts, Database of Abstracts of Reviews of Effects, CINAHL and Web of Science were systematically searched from January 1986- Feb 2018. Two reviewers independently screened titles and abstracts. Studies were excluded from the review if they were non-English language, theoretical or methodological articles, policy documents, conference abstracts or presentations, as where quotations were not clearly attributed to GPs participating in the study. The reviewers then independently assessed the full text of the articles using the Critical Appraisal Skills Programme (CASP) tool for qualitative research. The papers were coded by two researcher and these codes organised using Thematic Network Analysis. Basis themes were defined initially, organising themes were then developed followed by global themes which summarised the key theories emerging from the articles. Finally, a theoretical model was derived by the researchers using the global themes to explain the interplay between factors influencing opioid prescribing decisions. Results: From 7020 records, 18 full text papers were assessed, and 13 studies included in the synthesis; 9 were from USA, 3 from UK and 1 from Sweden. Seven organising themes were identified including trust and mistrust, the importance of aetiology, monitoring of prescription use, physical, psychological and societal harm, consultation variables, inadequate pain management, stigma and stereotypes and system barriers to effective and safe prescribing such as limited access to specialist care or support from allied healthcare professionals in primary care. Four global themes emerged;suspicion, risk, agreement and encompassing systems level factors. These global themes are inter-related and capture the complex decision-making processes underlying the opioid prescribing whereby the physician both consciously and subconsciously quantifies the risk-benefit relationship associated with initiating or continuing an opioid prescription. Conclusion: Prescribing of opioids for CNMP is influenced by a myriad of factors. Rather, than a simple risk-benefit view of the process, it is more useful to view this as a dynamic process in which unique considerations such as the morality of opioid use exert an effect. Recognising the inherent complexity of the process and the limitations of healthcare systems, guidelines directed at GPs should offer more nuanced recommendations on managing opioid prescribing consultations in primary care
The RISC-KIT storm impact database: A new tool in support of DRR
This paper presents a new storm impact database for European coastlines that facilitates the upload, browsing and download of a broad range of physical and impact information related to historical and recent marine storm events. The database is transparent in terms of open access to raw data and metadata, makes use of version control systems through the OpenEarth repository and promotes the use of international standards. A total of 298 storm events are currently stored in the database from the ten RISC-KIT case study sites, including historical events dating back to the sixteenth century. To demonstrate the application of the tool, examples of typical event data contained within the database as well as the ability of the database to identify impacts of events across regions are presented. It is envisaged that this database will expand beyond the ten case study sites, with the aim of promoting and greatly improving the collection and reporting of extreme hydro-meteorological events across Europe into the future
Monitoring neurotoxins in industry: development of a neurobehavioral test battery
Huguet Françoise. 104 - Elémens (Les) ou premières instructions de la jeunesse. In: , . Les Livres pour l'Enfance et la Jeunesse de Gutenberg à Guizot. Les collections de la Bibliothèque de l'Institut National de Recherche Pédagogique. Paris : Institut national de recherche pédagogique, 1997. p. 57. (Bibliothèque de l'Histoire de l'Education, 16
Occupational lead neurotoxicity: Improvement in behavioural effects after reduction of exposure.
To evaluate critical exposure levels and the reversibility of lead neurotoxicity a group of lead exposed foundry workers and an unexposed reference population were followed up for three years. During this period, tests designed to monitor neurobehavioural function and lead dose were administered. Evaluations of 160 workers during the first year showed dose dependent decrements in mood, visual/motor performance, memory, and verbal concept formation. Subsequently, an improvement in the hygienic conditions at the plant resulted in striking reductions in blood lead concentrations over the following two years. Attendant improvement in indices of tension (20% reduction), anger (18%), depression (26%), fatigue (27%), and confusion (13%) was observed. Performance on neurobehavioural testing generally correlated best with integrated dose estimates derived from blood lead concentrations measured periodically over the study period; zinc protoporphyrin levels were less well correlated with function. This investigation confirms the importance of compliance with workplace standards designed to lower exposures to ensure that individual blood lead concentrations remain below 50 micrograms/dl
Approximate Flavor Symmetries in the Lepton Sector
Approximate flavor symmetries in the quark sector have been used as a handle
on physics beyond the Standard Model. Due to the great interest in neutrino
masses and mixings and the wealth of existing and proposed neutrino experiments
it is important to extend this analysis to the leptonic sector. We show that in
the see-saw mechanism, the neutrino masses and mixing angles do not depend on
the details of the right-handed neutrino flavor symmetry breaking, and are
related by a simple formula. We propose several ans\"{a}tze which relate
different flavor symmetry breaking parameters and find that the MSW solution to
the solar neutrino problem is always easily fit. Further, the oscillation is unlikely to solve the atmospheric neutrino problem
and, if we fix the neutrino mass scale by the MSW solution, the neutrino masses
are found to be too small to close the Universe.Comment: 12 pages (no figures), LBL-3459
Can an early-warning system help minimize the impacts of coastal storms? A case study of the 2012 Halloween storm, northern Italy
Abstract. The Emilia-Romagna early-warning system (ER-EWS) is a state-of-the-art coastal forecasting system that comprises a series of numerical models (COSMO, ROMS, SWAN and XBeach) to obtain a daily 3-day forecast of coastal storm hazard at eight key sites along the Emilia-Romagna coastline (northern Italy). On the night of 31 October 2012, a major storm event occurred that resulted in elevated water levels (equivalent to a 1-in-20- to 1-in-50-year event) and widespread erosion and flooding. Since this storm happened just 1 month prior to the roll-out of the ER-EWS, the forecast performance related to this event is unknown. The aim of this study was to therefore reanalyse the ER-EWS as if it had been operating a day before the event and determine to what extent the forecasts may have helped reduce storm impacts. Three different reanalysis modes were undertaken: (1) a default forecast (DF) mode based on 3-day wave and water-level forecasts and default XBeach parameters; (2) a measured offshore (MO) forecast mode using wave and water-level measurements and default XBeach parameters; and (3) a calibrated XBeach (CX) mode using measured boundary conditions and an optimized parameter set obtained through an extensive calibration process. The results indicate that, while a "code-red" alert would have been issued for the DF mode, an underprediction of the extreme water levels of this event limited high-hazard forecasts to only two of the eight ER-EWS sites. Forecasts based on measured offshore conditions (the MO mode) more-accurately indicate high-hazard conditions for all eight sites. Further considerable improvements are observed using an optimized XBeach parameter set (the CX mode) compared to default parameters. A series of what-if scenarios at one of the sites show that artificial dunes, which are a common management strategy along this coastline, could have hypothetically been constructed as an emergency procedure to potentially reduce storm impacts
Immunopathology of CD4+ T Cell-Mediated Autoimmune Responses to Central Nervous System Antigens: Role of IL-16
Multiple sclerosis (MS) is a chronic, inflammatory, demyelinating and degenerative disease of the central nervous system (CNS). While etiology of the disease remains unknown, genetic susceptibility and autoimmune mechanisms in the initiation and progression of the disease have been strongly suggested. Experimental autoimmune encephalomyelitis (EAE) is commonly used to study immune regulation of MS. Infiltration by CD4+ T cells, through blood-brain barrier (BBB), precedes the onset and relapses of MS. CNS migration and homing patterns of T cells are tightly synchronized by astrocyte and microglia derived cytokines and chemokines. Autoimmune, CNS antigenreactive, infiltrating T cells produce and locally release cytokines including but not limited to IFNγ, IL-2, IL-6, IL-16, IL-17, TNFα, and chemokines including CCL2, CCL5 and CXCL10. Chemokine mediated chemotaxis is exclusive for activated cell state and most chemokines do not discriminate between distinct cell types. Conversely, a cytokine IL-16 is a CD4-specific cytokine-ligand and exclusively induces chemotaxis of CD4+T cells, by binding and signaling through CD4, regardless of T cell activation state. In this article we focus on CD4+ T cell-mediated autoimmune responses to CNS antigens because of their importance for immunopathology of MS and EAE. We focus on autoimmune responses to myelin oligodendrocyte glycoprotein (MOG) because of its relevance for immunopathology of MS. We emphasize a role of IL-16 in regulation of CD4+T cell mediated autoimmune responses to MOG in EAE and MS. While a role of IL-16 in regulation of other CD4+T cell mediated autoimmune diseases has been established, its role in regulation of MS remains to be determined. Emerging data from our laboratories have indicated that IL-16-mediated CD4+ T cell chemoattraction has a significant role in regulation of CD4+ T cell-mediated autoimmune responses to CNS antigens. We propose an important function of this cytokine in regulation of relapsing-remitting EAE
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