Mechanisms of offshore solid and liquid freshwater flux from the East Greenland Current

The mechanisms that control the export of freshwater from the East Greenland Current, in both liquid and solid form, are explored using an idealized numerical model and scaling theory. A regional, coupled ocean–sea ice model is applied to a series of calculations in which key parameters are varied and the scaling theory is used to interpret the model results. The offshore ice flux, occurring in late winter, is driven primarily by internal stresses and is most sensitive to the thickness of sea ice on the shelf coming out of Fram Strait and the strength of alongshore winds over the shelf. The offshore liquid freshwater flux is achieved by eddy fluxes in late summer while there is an onshore liquid freshwater flux in winter due to the ice–ocean stress, resulting in only weak annual mean flux. The scaling theory identifies the key nondimensional parameters that control the behavior and reproduces the general parameter dependence found in the numerical model. Climate models predict that winds will increase and ice export from the Arctic will decrease in the future, both of which will lead to a decrease in the offshore flux of sea ice, while the influence on liquid freshwater may increase or decrease, depending on the relative changes in the onshore Ekman transport and offshore eddy fluxes. Additional processes that have not been considered here, such as more complex topography and synoptic wind events, may also contribute to cross-shelf exchange.publishedVersio

SEXTANT X-Ray Pulsar Navigation Demonstration: Additional On-Orbit Results

The Station Explorer for X-ray Timing and Navigation Technology (SEXTANT) is a technology demonstration enhancement to the Neutron-star Interior Composition Explorer (NICER) mission, a NASA Astrophysics Explorer Mission of Opportunity to the International Space Station, launched in June of 2017. In late 2017, SEXTANT successfully completed a first demonstration of in-space and autonomous X-ray pulsar navigation (XNAV). This form of navigation relies on processing faint signals from millisecond pulsars-rapidly rotating neutron stars that appear to pulsate in the X-ray band-and could potentially provide a GPS-like navigation capability applicable throughout the solar-system and beyond. In this work, we briefly review prior SEXTANT results and then present new results focusing on: making use of the high- flux but rotationally unstable Crab pulsar, and using XNAV to estimate position, velocity, and time in the presence of an imperfect local clock

The ‘Dark Side’ and ‘Bright Side’ of Personality: When Too Much Conscientiousness and Too Little Anxiety Are Detrimental with Respect to the Acquisition of Medical Knowledge and Skill

Theory suggests that personality traits evolved to have costs and benefits, with the effectiveness of a trait dependent on how these costs and benefits relate to the present circumstances. This suggests that traits that are generally viewed as positive can have a ‘dark side’ and those generally viewed as negative can have a ‘bright side’ depending on changes in context. We test this in a sample of 220 UK medical students with respect to associations between the Big 5 personality traits and learning outcomes across the 5 years of a medical degree. The medical degree offers a changing learning context from pre-clinical years (where a more methodical approach to learning is needed) to the clinical years (where more flexible learning is needed, in a more stressful context). We argue that while trait conscientiousness should enhance pre-clinical learning, it has a ‘dark side’ reducing the acquisition of knowledge in the clinical years. We also suggest that anxiety has a ‘bright side’ enhancing the acquisition of skills in the clinical years. We also explore if intelligence enhances learning across the medical degree. Using confirmatory factor analysis and structural equation modelling we show that medical skills and knowledge assessed in the pre-clinical and clinical years are psychometrically distinguishable, forming a learning ‘backbone’, whereby subsequent learning outcomes are predicted by previous ones. Consistent with our predictions conscientiousness enhanced preclinical knowledge acquisition but reduced the acquisition of clinical knowledge and anxiety enhanced the acquisition of clinical skills. We also identified a curvilinear U shaped association between Surgency (extraversion) and pre-clinical knowledge acquisition. Intelligence predicted initial clinical knowledge, and had a positive total indirect effect on clinical knowledge and clinical skill acquisition. For medical selection, this suggests that selecting students high on conscientiousness may be problematic, as it may be excluding those with some degree of moderate anxiety

Eficiencia en el uso del agua en trigo y lino oleaginoso con distintos aportes de nitrógeno en la región semiárida pampeana central

La región agrícola de la provincia de La Pampa con aptitud para el cultivo de trigo, posee también condiciones agro-ecológicas adecuadas para el desarrollo de lino oleaginoso, ofreciendo excelentes posibilidades, con lo cual esta especie surge como un interesante cultivo invernal alternativo al trigo u otros cereales de invierno. Los cereales de invierno experimentan limitaciones para expresar su rendimiento potencial en regiones semiáridas. Estas limitaciones pueden deberse al genotipo, a los factores ambientales y/o a la interacción de ambos. El propósito de este trabajo fue analizar el efecto de la fertilización nitrogenada sobre los distintos componentes del rendimiento y su impacto en la eficiencia en el uso del agua (EUA) en trigo pan y lino oleaginoso En el campo experimental de la Facultad de Agronomía de la Universidad Nacional de La Pampa se condujo el ensayo, en el cual se compararon las dos especies: trigo pan y lino oleaginoso, bajo cuatro condiciones de fertilidad. En las condiciones en las cuales se llevó a cabo el ensayo no se pudo comprobar la hipótesis de que el agregado de fertilizante nitrogenado aumenta la EUA. Por el contrario, parece que en condiciones de sequía tendría un efecto inverso. Se encontró que el trigo presenta una mayor eficiencia en el uso del agua que el lino en cuanto a la producción de materia seca, y este último no presentó ninguna respuesta significativa en a EUA frente al agregado de fertilizante nitrogenado

Comparative performance of four rapid Ebola antigen-detection lateral flow immunoassays during the 2014-2016 Ebola epidemic in West Africa

BACKGROUND: Without an effective vaccine, as was the case early in the 2014-2016 Ebola Outbreak in West Africa, disease control depends entirely on interrupting transmission through early disease detection and prompt patient isolation. Lateral Flow Immunoassays (LFI) are a potential supplement to centralized reference laboratory testing for the early diagnosis of Ebola Virus Disease (EVD). The goal of this study was to assess the performance of commercially available simple and rapid antigen detection LFIs, submitted for review to the WHO via the Emergency Use Assessment and Listing procedure. The study was performed in an Ebola Treatment Centre laboratory involved in EVD testing in Sierra Leone. In light of the current Ebola outbreak in May 2018 in the Democratic Republic of Congo, which highlights the lack of clarity in the global health community about appropriate Ebola diagnostics, our findings are increasingly critical. METHODS: A cross-sectional study was conducted to assess comparative performance of four LFIs for detecting EVD. LFIs were assessed against the same 328 plasma samples and 100 whole EDTA blood samples, using the altona RealStar Filovirus Screen real-time RT-PCR as the bench mark assay. The performance of the Public Health England (PHE) in-house Zaire ebolavirus-specific real time RT-PCR Trombley assay was concurrently assessed. Statistical analysis using generalized estimating equations was conducted to compare LFI performance. FINDINGS: Sensitivity and specificity varied between the LFIs, with specificity found to be significantly higher for whole EDTA blood samples compared to plasma samples in at least 2 LFIs (P≤0.003). Using the altona RT-PCR assay as the bench mark, sensitivities on plasma samples ranged from 79.53% (101/127, 95% CI: 71.46-86.17%) for the DEDIATEST EBOLA (SD Biosensor) to 98.43% (125/127, 95% CI: 94.43-99.81%) for the One step Ebola test (Intec). Specificities ranged from 80.20% (158/197, 95% CI: 74.07-88.60%) for plasma samples using the ReEBOV Antigen test Kit (Corgenix) to 100.00% (98/98, 95% CI: 96.31-100.00%) for whole blood samples using the DEDIATEST EBOLA (SD Biosensor) and SD Ebola Zaire Ag (SD Biosensor). Results also showed the Trombley RT-PCR assay had a lower limit of detection than the altona assay, with some LFIs having higher sensitivity than the altona assay when the Trombley assay was the bench mark. INTERPRETATION: All of the tested EVD LFIs may be considered suitable for use in an outbreak situation (i.e. rule out testing in communities), although they had variable performance characteristics, with none possessing both high sensitivity and specificity. The non-commercial Trombley Zaire ebolavirus RT-PCR assay warrants further investigation, as it appeared more sensitive than the current gold standard, the altona Filovirus Screen RT-PCR assay

Longitudinal assessment of symptoms and risk of SARS-CoV-2 infection in healthcare workers across 5 hospitals to understand ethnic differences in infection risk

Background: : Healthcare workers (HCWs) have increased rates of SARS-CoV-2 infection compared with the general population. We aimed to understand ethnic differences in SARS-CoV-2 seropositivity among hospital healthcare workers depending on their hospital role, socioeconomic status, Covid-19 symptoms and basic demographics. Methods: A prospective longitudinal observational cohort study. 1364 HCWs at five UK hospitals were studied with up to 16 weeks of symptom questionnaires and antibody testing (to both nucleocapsid and spike protein) during the first UK wave in five NHS hospitals between March 20 and July 10 2020. The main outcome measures were SARS-CoV-2 infection (seropositivity at any time-point) and symptoms. Findings: 272 of 1364 HCWs (mean age 40.7 years, 72% female, 74% White, >= 6 samples per participant) seroconverted, reporting predominantly mild or no symptoms. Seropositivity was lower in Intensive Therapy Unit (ITU) workers (OR=0.44 95%CI 0.24, 0.77; p=0.0035). Seropositivity was higher in Black (compared to White) participants, independent of age, sex, role and index of multiple deprivation (OR=2.61 95%CI 1.474.62 p=0.0009). No association was seen between White HCWs and other minority ethnic groups. Interpretation: In the UK first wave, Black ethnicity (but not other ethnicities) more than doubled HCWs likelihood of seropositivity, independent of age, sex, measured socio-economic factors and hospital role

Longitudinal assessment of symptoms and risk of SARS-CoV-2 infection in healthcare workers across 5 hospitals to understand ethnic differences in infection risk.

BACKGROUND: Healthcare workers (HCWs) have increased rates of SARS-CoV-2 infection compared with the general population. We aimed to understand ethnic differences in SARS-CoV-2 seropositivity among hospital healthcare workers depending on their hospital role, socioeconomic status, Covid-19 symptoms and basic demographics. METHODS: A prospective longitudinal observational cohort study. 1364 HCWs at five UK hospitals were studied with up to 16 weeks of symptom questionnaires and antibody testing (to both nucleocapsid and spike protein) during the first UK wave in five NHS hospitals between March 20 and July 10 2020. The main outcome measures were SARS-CoV-2 infection (seropositivity at any time-point) and symptoms. Registration number: NCT04318314. FINDINGS: 272 of 1364 HCWs (mean age 40.7 years, 72% female, 74% White, ≥6 samples per participant) seroconverted, reporting predominantly mild or no symptoms. Seropositivity was lower in Intensive Therapy Unit (ITU) workers (OR=0.44 95%CI 0.24, 0.77; p=0.0035). Seropositivity was higher in Black (compared to White) participants, independent of age, sex, role and index of multiple deprivation (OR=2.61 95%CI 1.47-4.62 p=0.0009). No association was seen between White HCWs and other minority ethnic groups. INTERPRETATION: In the UK first wave, Black ethnicity (but not other ethnicities) more than doubled HCWs likelihood of seropositivity, independent of age, sex, measured socio-economic factors and hospital role

A novel approach to process brittle ice for continuous flow analysis of stable water isotopes

ABSTRACTBrittle ice, which occurs in all intermediate-depth and deep ice cores retrieved from high-latitude regions, presents a challenge for high-resolution measurements of water isotopes, gases, ions and other quantities conducted with continuous flow analysis (CFA). We present a novel method of preserving brittle ice for CFA stable water isotope measurements using data from a new ice core recovered by the Roosevelt Island Climate Evolution (RICE) project. Modest modification of the drilling technique and the accommodation of non-horizontal fractures (‘slanted breaks’) in processing led to a substantial improvement in the percentage of brittle ice analyzed with CFA (87.8%). Whereas traditional processing methods remove entire fragmented pieces of ice, our method allowed the incorporation of a total of 3 m of ice (1% of the 261 m of brittle ice and ~1300 years of climate history) that otherwise would not have been available for CFA. Using the RICE stable water isotope CFA dataset, we demonstrate the effect of slanted breaks and analyze the resulting smoothing of the data with real and simulated examples. Our results suggest that retaining slanted breaks are a promising technique for preserving brittle ice material for CFA stable water isotope measurements.</jats:p