860 research outputs found

    Automated Laboratory and Field Techniques to Determine Greenhouse Gas Emissions

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    Methods and techniques are described for automated measurements of greenhouse gases (GHGs) in both the laboratory and the field. Robotic systems are currently available to measure the entire range of gases evolved from soils including dinitrogen (N 2 ). These systems usually work on an exchange of the atmospheric N 2 with helium (He) so that N 2 fluxes can be determined. Laboratory systems are often used in microbiology to determine kinetic response reactions via the dynamics of all gaseous N species such as nitric oxide (NO), nitrous oxide (N 2 O), and N 2 . Latest He incubation techniques also take plants into account, in order to study the effect of plant–soil interactions on GHGsand N 2 production. The advantage of automated in-field techniques is that GHG emission rates can be determined at a high temporal resolution. This allows, for instance, to determine diurnal response reactions (e.g. with temperature) and GHG dynamics over longer time periods

    Micrometeorological Methods for Greenhouse Gas Measurement

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    Micrometeorological techniques are useful if greenhouse gas (GHG) emissions from larger areas (i.e. entire fields) should be integrated. The theory and the various techniques such as flux-gradient, aerodynamic, and Bowen ratio as well as Eddy correlation methods are described and discussed. Alternative methods also used are Eddy correlation, mass balance techniques, and tracer-based methods. The analytical techniques with current state-of-the-art approaches as well as the calculation procedures are presented

    Creating the Pick's disease International Consortium: Association study of MAPT H2 haplotype with risk of Pick's disease.

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    A science-based agenda for health-protective chemical assessments and decisions: overview and consensus statement

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    Abstract The manufacture and production of industrial chemicals continues to increase, with hundreds of thousands of chemicals and chemical mixtures used worldwide, leading to widespread population exposures and resultant health impacts. Low-wealth communities and communities of color often bear disproportionate burdens of exposure and impact; all compounded by regulatory delays to the detriment of public health. Multiple authoritative bodies and scientific consensus groups have called for actions to prevent harmful exposures via improved policy approaches. We worked across multiple disciplines to develop consensus recommendations for health-protective, scientific approaches to reduce harmful chemical exposures, which can be applied to current US policies governing industrial chemicals and environmental pollutants. This consensus identifies five principles and scientific recommendations for improving how agencies like the US Environmental Protection Agency (EPA) approach and conduct hazard and risk assessment and risk management analyses: (1) the financial burden of data generation for any given chemical on (or to be introduced to) the market should be on the chemical producers that benefit from their production and use; (2) lack of data does not equate to lack of hazard, exposure, or risk; (3) populations at greater risk, including those that are more susceptible or more highly exposed, must be better identified and protected to account for their real-world risks; (4) hazard and risk assessments should not assume existence of a “safe” or “no-risk” level of chemical exposure in the diverse general population; and (5) hazard and risk assessments must evaluate and account for financial conflicts of interest in the body of evidence. While many of these recommendations focus specifically on the EPA, they are general principles for environmental health that could be adopted by any agency or entity engaged in exposure, hazard, and risk assessment. We also detail recommendations for four priority areas in companion papers (exposure assessment methods, human variability assessment, methods for quantifying non-cancer health outcomes, and a framework for defining chemical classes). These recommendations constitute key steps for improved evidence-based environmental health decision-making and public health protection

    Methodology for Measuring Greenhouse Gas Emissions from Agricultural Soils Using Non-isotopic Techniques

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    Several approaches exist for measuring greenhouse gases (GHGs), mainly CO 2 , N 2 O, and CH 4 , from soil surfaces. The principle methods that are used to measure GHG from agricultural sites are chamber-based techniques. Both open and closed chamber techniques are in use; however, the majority of field applications use closed chambers. The advantages and disadvantages of different chamber techniques and the principal steps of operation are described. An important part of determining the quality of the flux measurements is the storage and the transportation of the gas samples from the field to the laboratory where the analyses are carried out. Traditionally, analyses of GHGs are carried out via gas chromatographs (GCs). In recent years, optical analysers are becoming increasingly available; these are user-friendly machines and they provide a cost-effective alternative to GCs. Another technique which is still under development, but provides a potentially superior method, is Raman spectroscopy. Not only the GHGs, but also N 2 , can potentially be analysed if the precision of these techniques is increased in future development. An important part of this chapter deals with the analyses of the gas concentrations, the calculation of fluxes, and the required safety measures. Since non-upland agricultural lands (i.e. flooded paddy soils) are steadily increasing, a section is devoted to the specificities of GHG measurements in these ecosystems. Specialised techniques are also required for GHG measurements in aquatic systems (i.e. rivers), which are often affected by the transfer of nutrients from agricultural fields and therefore are an important indirect source of emission of GHGs. A simple, robust, and more precise methodof ammonia (NH 3 ) emission measurement is also described

    Isotopic Techniques to Measure N2O, N2 and Their Sources

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    GHG emissions are usually the result of several simultaneous processes. Furthermore, some gases such as N2 are very difficult to quantify and require special techniques. Therefore, in this chapter, the focus is on stable isotope methods. Both natural abundance techniques and enrichment techniques are used. Especially in the last decade, a number of methodological advances have been made. Thus, this chapter provides an overview and description of a number of current state-of-the-art techniques, especially techniques using the stable isotope 15N. Basic principles and recent advances of the 15N gas flux method are presented to quantify N2 fluxes, but also the latest isotopologue and isotopomer methods to identify pathways for N2O production. The second part of the chapter is devoted to 15N tracing techniques, the theoretical background and recent methodological advances. A range of different methods is presented from analytical to numerical tools to identify and quantify pathway-specific N2O emissions. While this chapter is chiefly concerned with gaseous N emissions, a lot of the techniques can also be applied to other gases such as methane (CH4), as outlined in Sect. 5.3

    Greenhouse Gases from Agriculture

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    The rapidly changing global climate due to increased emission of anthropogenic greenhouse gases (GHGs) is leading to an increased occurrence of extreme weather events such as droughts, floods, and heatwaves. The three major GHGs are carbon dioxide (CO 2 ), methane (CH 4 ), and nitrous oxide (N 2 O). The major natural sources of CO 2 include ocean–atmosphere exchange, respiration of animals, soils (microbial respiration) and plants, and volcanic eruption; while the anthropogenic sources include burning of fossil fuel (coal, natural gas, and oil), deforestation, and the cultivation of land that increases the decomposition of soil organic matter and crop and animal residues. Natural sources of CH 4 emission include wetlands, termite activities, and oceans. Paddy fields used for rice production, livestock production systems (enteric emission from ruminants), landfills, and the production and use of fossil fuels are the main anthropogenic sources of CH 4 . Nitrous oxide, in addition to being a major GHG, is also an ozone-depleting gas. N 2 O is emitted by natural processes from oceans and terrestrial ecosystems. Anthropogenic N 2 O emissions occur mostly through agricultural and other land-use activities and are associated with the intensification of agricultural and other human activities such as increased use of synthetic fertiliser (119.4 million tonnes of N worldwide in 2019), inefficient use of irrigation water, deposition of animal excreta (urine and dung) from grazing animals, excessive and inefficient application of farm effluents and animal manure to croplands and pastures, and management practices that enhance soil organic N mineralisation and C decomposition. Agriculture could act as a source and a sink of GHGs. Besides direct sources, GHGs also come from various indirect sources, including upstream and downstream emissions in agricultural systems and ammonia (NH 3 ) deposition from fertiliser and animal manure

    Factors that influence treatment decisions: A qualitative study of racially and ethnically diverse patients with low‐ and very‐low risk prostate cancer

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    Abstract Background Factors that influence prostate cancer treatment decisions are complex, multifaceted, and personal, and may vary by race/ethnicity. Although research has been published to quantify factors involved in decision‐making, these studies have been limited to primarily white, and to a lesser extent, Black patients, and quantitative studies are limited for discerning the cultural and contextual processes that shape decision‐making. Methods We conducted 43 semi‐structured interviews with a racially and ethnically diverse sample of patients diagnosed with low‐ and very‐low risk prostate cancer who had undergone treatment for their prostate cancer. Interviews were transcribed, independently coded, and analyzed to identify themes salient for decision‐making, with attention to sociocultural differences. Results We found racial and ethnic differences in three areas. First, we found differences in how socialized masculinity influenced patient's feelings about different treatment options. Second, we found that for some men, religion and spirituality alleviated anxiety associated with the active surveillance protocol. Finally, for racially and ethnically minoritized patients, we found descriptions of how historic and social experiences within the healthcare system influenced decision‐making. Conclusions Our study adds to the current literature by expounding on racial and ethnic differences in the multidimensional, nuanced factors related to decision‐making. Our findings suggest that factors associated with prostate cancer decision‐making can manifest differently across racial and ethnic groups, and provide some guidance for future research