523 research outputs found

    Observation of O+ 4P-4D0 lines in proton aurora over Svalbard

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    Spectra of a proton aurora event show lines of O+ 4P-4D0 multiplet (4639–4696 Å) enhanced relative to the N2 +1N(0,2) compared to normal electron aurora. Conjugate satellite particle measurements are used as input to electron and proton transport models, to show that p/H precipitation is the dominant source of both the O+ and N2 +1N emissions. The emission cross-section of the multiplet in p collisions with O and O2 estimated from published work does not explain the observed O+ brightness, suggesting a higher emission cross-section for low energy p impact on O

    Livelihood impacts of flash floods in Cox’s Bazar District, Bangladesh

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    This article aims to understand local views and understandings of livelihood impacts of flash floods, and how to tackle the challenges. The work is completed through case studies of two villages in Cox’s Bazar District in south-east Bangladesh, Manirjhil and Chotojamchori. Based in theoretical understandings from disaster research of how underlying conditions rather than hazards cause disasters, this empirical study combined household surveys and participatory rural appraisal (PRA) techniques for collecting field data. The results detail local perspectives of underlying conditions—namely poverty, inequity, precarious livelihoods, and few contingency options—impacting livelihoods, especially highlighting food, water, disease, and migration, all of which link directly to livelihoods. A significant concern is the need to take out loans which can contribute to continuing poverty. Suggested strategies for dealing with flash flood impacts were based in local contexts and did not always account for broader remits, such as the deep-seated gendered nature of societal roles in Bangladesh or power and governance structures within the Bangladeshi context

    Resilience to flash floods in wetland communities of northeastern Bangladesh

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    Globally, a number of catastrophic hydrometeorological hazards occurred in 2017 among which the monsoon floods in South Asia was particularly disastrous, killing nearly 1200 people in India, Nepal and Bangladesh. The wetland region (Haor) of northeastern (NE) Bangladesh was severely affected by flash floods early in 2017, affecting nearly 1 million households and damaging US $450 million worth of rice crops. This study investigates how the NE Bangladesh experienced the 2017 flash floods, and to what degree the wetland communities are vulnerable and resilience to flash floods. Focus group discussion, key informant interviews, and household questionnaire surveys (n = 80) were applied in the study area of Sunamganj district. Results from statistical analyses and regression modelling reveal that poor people are particularly vulnerable to floods but they are also more adaptive and thus resilient; middle-income households are vulnerable as they are hesitant to take up any jobs and accept flood relief; and rich households, despite being less adaptive, are able to recover from flood disasters because of wealth. This study reveals that resilience also stems from deep religious faith in the Haor inhabitants that supports communities to move on by accepting that most natural calamities such as flash floods are divine tests. This study also finds that women are particularly vulnerable and less resilient as they are not normally allowed to work outside of their homes and beyond the Haor communities due to cultural and religious reasons

    Ecofeminism in the 21st Century

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    This paper considers the influence of ecofeminism on policy concerning gender (in)equality and the environment during the past 20 years. It reviews the broad contours of the ecofeminist debate before focusing on the social construction interpretation of women's relationship with the environment. It will argue that there have been substantial policy shifts in Europe and the UK in both the environmental and equalities fields, and that this is in part a result of lobbying at a range of scales by groups informed by ecofeminist debates. Nevertheless, the paper cautions that these shifts are largely incremental and operate within existing structures, which inevitably limit their capacity to create change. As policy addresses some of the concerns highlighted by ecofeminism, academic discourse and grass roots activity have been moving on to address other issues, and the paper concludes with a brief consideration of contemporary trajectories of ecofeminism and campaigning on issues that link women's, feminist and environment concerns

    Warning systems as social processes for Bangladesh cyclones

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    Purpose: The purpose of this paper is to connect the theoretical idea of warning systems as social processes with empirical data of people’s perceptions of and actions for warning for cyclones in Bangladesh. / Design/methodology/approach: A case study approach is used in two villages of Khulna district in southwest Bangladesh: Kalabogi and Kamarkhola. In total, 60 households in each village were surveyed with structured questionnaires regarding how they receive their cyclone warning information as well as their experiences of warnings for Cyclone Sidr in 2007 and Cyclone Aila in 2009. / Findings: People in the two villages had a high rate of receiving cyclone warnings and accepted them as being credible. They also experienced high impacts from the cyclones. Yet evacuation rates to cyclone shelters were low. They did not believe that significant cyclone damage would affect them and they also highlighted the difficulty of getting to cyclone shelters due to poor roads, leading them to prefer other evacuation options which were implemented if needed. / Originality/value: Theoretical constructs of warning systems, such as the First Mile and late warning, are rarely examined empirically according to people’s perceptions of warnings. The case study villages have not before been researched with respect to warning systems. The findings provide empirical evidence for long-established principles of warning systems as social processes, usually involving but not relying on technical components

    Test Characteristics of Urinary Lipoarabinomannan and Predictors of Mortality among Hospitalized HIV-Infected Tuberculosis Suspects in Tanzania.

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    Tuberculosis is the most common cause of death among patients with HIV infection living in tuberculosis endemic countries, but many cases are not diagnosed pre-mortem. We assessed the test characteristics of urinary lipoarabinomannan (LAM) and predictors of mortality among HIV-associated tuberculosis suspects in Tanzania. We prospectively enrolled hospitalized HIV-infected patients in Dar es Salaam, with ≄2 weeks of cough or fever, or weight loss. Subjects gave 2 mLs of urine to test for LAM using a commercially available ELISA, ≄2 sputum specimens for concentrated AFB smear and solid media culture, and 40 mLs of blood for culture. Among 212 evaluable subjects, 143 (68%) were female; mean age was 36 years; and the median CD4 count 86 cells/mm(3). 69 subjects (33%) had culture confirmation of tuberculosis and 65 (31%) were LAM positive. For 69 cases of sputum or blood culture-confirmed tuberculosis, LAM sensitivity was 65% and specificity 86% compared to 36% and 98% for sputum smear. LAM test characteristics were not different in patients with bacteremia but showed higher sensitivity and lower specificity with decreasing CD4 cell count. Two month mortality was 64 (53%) of 121 with outcomes available. In multivariate analysis there was significant association of mortality with absence of anti-retroviral therapy (p = 0.004) and a trend toward association with a positive urine LAM (p = 0.16). Among culture-negative patients mortality was 9 (75%) of 12 in LAM positive patients and 27 (38%) of 71 in LAM negative patients (p = 0.02). Urine LAM is more sensitive than sputum smear and has utility for the rapid diagnosis of culture-confirmed tuberculosis in this high-risk population. Mortality data raise the possibility that urine LAM may also be a marker for culture-negative tuberculosis

    Measurement of the diffractive structure function in deep inelastic scattering at HERA

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    This paper presents an analysis of the inclusive properties of diffractive deep inelastic scattering events produced in epep interactions at HERA. The events are characterised by a rapidity gap between the outgoing proton system and the remaining hadronic system. Inclusive distributions are presented and compared with Monte Carlo models for diffractive processes. The data are consistent with models where the pomeron structure function has a hard and a soft contribution. The diffractive structure function is measured as a function of \xpom, the momentum fraction lost by the proton, of ÎČ\beta, the momentum fraction of the struck quark with respect to \xpom, and of Q2Q^2. The \xpom dependence is consistent with the form \xpoma where a = 1.30 ± 0.08 (stat) − 0.14+ 0.08 (sys)a~=~1.30~\pm~0.08~(stat)~^{+~0.08}_{-~0.14}~(sys) in all bins of ÎČ\beta and Q2Q^2. In the measured Q2Q^2 range, the diffractive structure function approximately scales with Q2Q^2 at fixed ÎČ\beta. In an Ingelman-Schlein type model, where commonly used pomeron flux factor normalisations are assumed, it is found that the quarks within the pomeron do not saturate the momentum sum rule.Comment: 36 pages, latex, 11 figures appended as uuencoded fil

    Heterogeneous disease-propagating stem cells in juvenile myelomonocytic leukemia

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    Juvenile myelomonocytic leukemia (JMML) is a poor-prognosis childhood leukemia usually caused by RAS-pathway mutations. The cellular hierarchy in JMML is poorly characterized, including the identity of leukemia stem cells (LSCs). FACS and single-cell RNA sequencing reveal marked heterogeneity of JMML hematopoietic stem/progenitor cells (HSPCs), including an aberrant Lin-CD34+CD38-CD90+CD45RA+ population. Single-cell HSPC index-sorting and clonogenic assays show that (1) all somatic mutations can be backtracked to the phenotypic HSC compartment, with RAS-pathway mutations as a "first hit,"(2) mutations are acquired with both linear and branching patterns of clonal evolution, and (3) mutant HSPCs are present after allogeneic HSC transplant before molecular/clinical evidence of relapse. Stem cell assays reveal interpatient heterogeneity of JMML LSCs, which are present in, but not confined to, the phenotypic HSC compartment. RNA sequencing of JMML LSC reveals upregulation of stem cell and fetal genes (HLF, MEIS1, CNN3, VNN2, and HMGA2) and candidate therapeutic targets/biomarkers (MTOR, SLC2A1, and CD96), paving the way for LSC-directed disease monitoring and therapy in this disease
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