688 research outputs found

    Rising oceans guaranteed: Arctic land ice loss and sea level rise

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    Purpose of Review This paper reviews sea level contributions from land ice across the Arctic, including Greenland. We summarize ice loss measurement methods, ice loss mechanisms, and recent observations and projections, and highlight research advances over the last 3-5 years and remaining scientific challenges. Recent Findings Mass loss across the Arctic began to accelerate during the late twentieth century, with projections of continued loss across all future greenhouse gas emission scenarios. Recent research has improved knowledge of ice hydrology and surface processes, influences of atmospheric and oceanic changes on land ice, and boundary conditions such as subglacial topography. New computer models can also more accurately simulate glacier and ice sheet evolution. Summary Rapid Arctic ice loss is underway, and future ice loss and sea level rise are guaranteed. Research continues to better understand and model physical processes and to improve projections of ice loss rates, especially after 2050

    Validation of a screening method for the detection of colistin-resistant \u3ci\u3eE. coli\u3c/i\u3e containing mcr-1 in feral swine feces

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    A method was developed and validated for the detection of colistin-resistant Escherichia coli containing mcr-1 in the feces of feral swine. Following optimization of an enrichment method using EC broth supplemented with colistin (1 μg/mL) and vancomycin (8 μg/mL), aliquots derived from 100 feral swine fecal samples were spiked with of one of five different mcr-1 positive E. coli strains (between 100 and 104 CFU/g), for a total of 1110 samples tested. Enrichments were then screened using a simple boil-prep and a previously developed real-time PCR assay for mcr-1 detection. The sensitivity of the method was determined in swine feces, with mcr-1 E. coli inocula of 0.1–9.99 CFU/g (n=340), 10–49.99 CFU/g (n=170), 50–99 CFU/g (n=255), 100–149 CFU/g (n=60), and 200–2200 CFU/g (n=175), which were detected with 32%, 72%, 88%, 95%, and 98% accuracy, respectively. Uninoculated controls (n = 100) were negative for mcr-1 following enrichment

    Gulls as Sources of Environmental Contamination by Colistin-resistant Bacteria

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    In 2015, the mcr-1 gene was discovered in Escherichia coli in domestic swine in China that conferred resistance to colistin, an antibiotic of last resort used in treating multi-drug resistant bacterial infections in humans. Since then, mcr-1 was found in other human and animal populations, including wild gulls. Because gulls could disseminate the mcr-1 gene, we conducted an experiment to assess whether gulls are readily colonized with mcr-1 positive E. coli, their shedding patterns, transmission among conspecifics, and environmental deposition. Shedding of mcr-1 E. coli by small gull flocks followed a lognormal curve and gulls shed one strain \u3e101 log10 CFU/g in their feces for 16.4 days, which persisted in the environment for 29.3 days. Because gulls are mobile and can shed antimicrobial-resistant bacteria for extended periods, gulls may facilitate transmission of mcr-1 positive E. coli to humans and livestock through fecal contamination of water, public areas and agricultural operations

    The global carbon budget 1959-2011

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    Accurate assessments of anthropogenic carbon dioxide (CO2) emissions and their redistribution among the atmosphere, ocean, and terrestrial biosphere is important to better understand the global carbon cycle, support the climate policy process, and project future climate change. Present-day analysis requires the combination of a range of data, algorithms, statistics and model estimates and their interpretation by a broad scientific community. Here we describe datasets and a methodology developed by the global carbon cycle science community to quantify all major components of the global carbon budget, including their uncertainties. We discuss changes compared to previous estimates, consistency within and among components, and methodology and data limitations. CO2 emissions from fossil fuel combustion and cement production (EFF) are based on energy statistics, while emissions from Land-Use Change (ELUC), including deforestation, are based on combined evidence from land cover change data, fire activity in regions undergoing deforestation, and models. The global atmospheric CO2 concentration is measured directly and its rate of growth (GATM) is computed from the concentration. The mean ocean CO2 sink (SOCEAN) is based on observations from the 1990s, while the annual anomalies and trends are estimated with ocean models. Finally, the global residual terrestrial CO2 sink (SLAND) is estimated by the difference of the other terms. For the last decade available (2002–2011), EFF was 8.3 ± 0.4 PgC yr−1, ELUC 1.0 ± 0.5 PgC yr−1, GATM 4.3 ± 0.1PgC yr−1, SOCEAN 2.5 ± 0.5 PgC yr−1, and SLAND 2.6 ± 0.8 PgC yr−1. For year 2011 alone, EFF was 9.5 ± 0.5 PgC yr−1, 3.0 percent above 2010, reflecting a continued trend in these emissions; ELUC was 0.9 ± 0.5 PgC yr−1, approximately constant throughout the decade; GATM was 3.6 ± 0.2 PgC yr−1, SOCEAN was 2.7 ± 0.5 PgC yr−1, and SLAND was 4.1 ± 0.9 PgC yr−1. GATM was low in 2011 compared to the 2002–2011 average because of a high uptake by the land probably in response to natural climate variability associated to La Niña conditions in the Pacific Ocean. The global atmospheric CO2 concentration reached 391.31 ± 0.13 ppm at the end of year 2011. We estimate that EFF will have increased by 2.6% (1.9–3.5%) in 2012 based on projections of gross world product and recent changes in the carbon intensity of the economy. All uncertainties are reported as ±1 sigma (68% confidence assuming Gaussian error distributions that the real value lies within the given interval), reflecting the current capacity to characterise the annual estimates of each component of the global carbon budget. This paper is intended to provide a baseline to keep track of annual carbon budgets in the future

    A study of surface currents in the spawning area of Brazilian sardine

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    To obtain the movement of surface currents in the spawning area of Brazilian sardine, drift card release experiments were conducted in south Brazilian waters during the spawning seasons of 1969-1971. The results of these experiments and some considerations about the drift of sardine eggs and larvae are described. On the cruises of late spring, summer and early autumn all cards from stations west of Long. 44º45' W drifted southwest and were recovered near São Sebastião and those from stations east of Long. 44º45' W drifted northeast and were recovered on the coast line between Ilha Grande and Cabo Frio. The drift pattern of the cruise of September 1969 was somewhat different from the others. Most cards recovered were released from stations near shore (up to 30 nm).O recrutamento do estoque de peixes marinhos é dependente da mortalidade, durante o estágio de ovos e larvas. A corrente de superfície, na área de desova, é um dos fatores importantes que afetam a mortalidade de larvas. O presente trabalho é o resultado de estudos feitos na corrente de superfície por meio de cartões-de-deriva, na região sul do Brasil (entre 22º S e 30º S). Oito viagens oceanográficas foram realizadas com os N/Oc. "Prof. W. Besnard" e "Emília" nos anos de 1969 a 1971. Na região de Ilha Grande, considerada uma das principais áreas de desova, o resultado na época do fim da primavera ao inicio do outono, mostra que os cartões lançados na área este de Long. 44º45' W, derivaram a nordeste e foram encontrados na costa, entre Ilha Grande e Cabo Frio e os cartões lançados na área oeste de Long. 44º45' W, derivaram a sudoeste e chegaram à costa de São Sebastião e Santos. O resultado do cruzeiro de setembro de 1969 (início da primavera) é diferente dos outros. Da região sul de Santos e da região do Cabo de São Tomé, temos poucos dados, portanto, não chegamos a uma conclusão definitiva. Será necessário o estudo contínuo desta área. A maioria dos cartões encontrados foram lançados de estações situadas perto da costa (no máximo, 30 mn). A maioria dos cartões, lançados a uma distância superior, nao foi recuperada

    Proactive and politically skilled professionals: What is the relationship with affective occupational commitment?

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    The aim of this study is to extend research on employee affective commitment in three ways: (1) instead of organizational commitment the focus is on occupational commitment; (2) the role of proactive personality on affective occupational commitment is examined; and (3) occupational satisfaction is examined as a mediator and political skills as moderator in the relationship between proactive personality and affective occupational commitment. Two connected studies, one in a hospital located in the private sector and one in a university located in the public sector, are carried out in Pakistan, drawing on a total sample of over 400 employees. The results show that proactive personality is positively related to affective occupational commitment, and that occupational satisfaction partly mediates the relationship between proactive personality and affective occupational commitment. No effect is found for a moderator effect of political skills in the relationship between proactive personality and affective occupational commitment. Political skills however moderate the relationship between proactive personality and affective organizational commitment
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