957 research outputs found

    On what scale can we predict the agronomic onset of the West African Monsoon?

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    Accurate prediction of the commencement of local rainfall over West Africa can provide vital information for local stakeholders and regional planners. However, in comparison with analysis of the regional onset of the West African Monsoon, the spatial variability of the local monsoon onset has not been extensively explored. One of the main reasons behind the lack of local onset forecast analysis is the spatial noisiness of local rainfall. A new method that evaluates the spatial scale at which local onsets are coherent across West Africa is presented. This new method can be thought of as analogous to a regional signal against local noise analysis of onset. This method highlights regions where local onsets exhibit a quantifiable degree of spatial consistency (denoted local onset regions or LORs). It is found that local onsets exhibit a useful amount of spatial agreement, with LORs apparent across the entire studied domain; this is in contrast to previously found results. Identifying local onset regions and understanding their variability can provide important insight into the spatial limit of monsoon predictability. Whilst local onset regions can be found over West Africa, their size is much smaller than the scale found for seasonal rainfall homogeneity. A potential use of local onset regions is presented that shows the link between the annual Inter-Tropical Front progression and local agronomic onset

    The interaction between moist diabatic processes and the atmospheric circulation in African Easterly Wave propagation

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    An objective tracking algorithm is used to characterise the three-dimensional structure of African EasterlyWaves (AEWs) in ERA-Interim reanalysis and a Met Office Unified Model (UM) simulation. A special focus is dedicated to the coupling of dynamical aspects of the wave and moist convection. The relation between baroclinic features of the wave and latent heating is explored. Latent heating at and slightly ahead of the wave trough is found to reinforce and sustain the anomalous wave circulation through potential vorticity (PV) generation and vortex stretching. The coupling of moist processes and the circulation takes place mainly through moisture convergence at lower mid-tropospheric levels, between 850 hPa and 500 hPa. These findings are confirmed and examined in more detail in a case study of a strong AEW based on high-resolution UM simulations. PV tracers are used to investigate how different moist diabatic processes invigorate the wave. Again moisture anomalies are found to be the main contributors to generating small-scale convergence centres and updrafts ahead of the trough at mid-tropospheric levels. Although buoyancy effects are ultimately responsible for the convective uplift, the results suggest that mesoscale circulations associated with the AEW dynamics are crucial in creating the small-scale moist static instabilities and vortices which are essential for the AEW maintenance. Boundary layer mixing and advection from the northern Sahel may create pockets of high-PV air around the trough in some instances, but this mechanism of wave sustainment needs further investigation

    Inhibitor of DNA Binding 3 Limits Development of Murine Slam-Associated Adaptor Protein-Dependent “Innate” γδ T cells

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    Id3 is a dominant antagonist of E protein transcription factor activity that is induced by signals emanating from the alphabeta and gammadelta T cell receptor (TCR). Mice lacking Id3 were previously shown to have subtle defects in positive and negative selection of TCRalphabeta+ T lymphocytes. More recently, Id3(-/-) mice on a C57BL/6 background were shown to have a dramatic expansion of gammadelta T cells.Here we report that mice lacking Id3 have reduced thymocyte numbers but increased production of gammadelta T cells that express a Vgamma1.1+Vdelta6.3+ receptor with restricted junctional diversity. These Vgamma1.1+Vdelta6.3+ T cells have multiple characteristics associated with "innate" lymphocytes such as natural killer T (NKT) cells including an activated phenotype, expression of the transcription factor PLZF, and rapid production of IFNg and interleukin-4. Moreover, like other "innate" lymphocyte populations, development of Id3(-/-) Vgamma1.1+Vdelta6.3+ T cells requires the signaling adapter protein SAP.Our data provide novel insight into the requirements for development of Vgamma1.1+Vdelta6.3+ T cells and indicate a role for Id3 in repressing the response of "innate" gammadelta T cells to SAP-mediated expansion or survival

    New Insights into the Evolution of Wolbachia Infections in Filarial Nematodes Inferred from a Large Range of Screened Species

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    Wolbachia are intriguing symbiotic endobacteria with a peculiar host range that includes arthropods and a single nematode family, the Onchocercidae encompassing agents of filariases. This raises the question of the origin of infection in filariae. Wolbachia infect the female germline and the hypodermis. Some evidences lead to the theory that Wolbachia act as mutualist and coevolved with filariae from one infection event: their removal sterilizes female filariae; all the specimens of a positive species are infected; Wolbachia are vertically inherited; a few species lost the symbiont. However, most data on Wolbachia and filaria relationships derive from studies on few species of Onchocercinae and Dirofilariinae, from mammals.We investigated the Wolbachia distribution testing 35 filarial species, including 28 species and 7 genera and/or subgenera newly screened, using PCR, immunohistochemical staining, whole mount fluorescent analysis, and cocladogenesis analysis. (i) Among the newly screened Onchocercinae from mammals eight species harbour Wolbachia but for some of them, bacteria are absent in the hypodermis, or in variable density. (ii) Wolbachia are not detected in the pathological model Monanema martini and in 8, upon 9, species of Cercopithifilaria. (iii) Supergroup F Wolbachia is identified in two newly screened Mansonella species and in Cercopithifilaria japonica. (iv) Type F Wolbachia infect the intestinal cells and somatic female genital tract. (v) Among Oswaldofilariinae, Waltonellinae and Splendidofilariinae, from saurian, anuran and bird respectively, Wolbachia are not detected.The absence of Wolbachia in 63% of onchocercids, notably in the ancestral Oswaldofilariinae estimated 140 mya old, the diverse tissues or specimens distribution, and a recent lateral transfer in supergroup F Wolbachia, modify the current view on the role and evolution of the endosymbiont and their hosts. Further genomic analyses on some of the newly sampled species are welcomed to decipher the open questions

    Slip-resistant footwear to reduce slips among health-care workers : the SSHeW RCT

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    Background In Great Britain, 100,000 injuries due to slips, trips and falls on the level (as opposed to falls from a height, e.g. a ladder) occur in the workplace each year. They are the most common cause of non-fatal injury in the workplace, accounting for 30% of all those injuries reported to the Health and Safety Executive. Nearly 1 million working days are lost because of slips, trips and falls each year. Objectives To assess the clinical effectiveness and cost-effectiveness of 5-star, GRIP-rated, slip-resistant footwear in preventing slips in the workplace compared with usual footwear. Design A two-arm, multicentre, randomised controlled trial with an economic evaluation and qualitative study. Setting Seven NHS trusts in England. Participants NHS staff aged ≥ 18 years, working at least 22.5 hours per week in clinical, general or catering areas who owned a mobile phone. Staff required to wear protective footwear were excluded. Interventions Intervention participants were offered 5-star, GRIP-rated, slip-resistant footwear. The waiting list control group were asked to wear their usual work shoes for the duration of the study and were offered the trial footwear at the end of their participation. Main outcome measures The primary outcome was the incidence rate of self-reported slips in the workplace over 14 weeks. Secondary outcomes included the incidence rate of falls either resulting from a slip or not resulting from a slip, proportion of participants reporting a slip, fall or fracture, time to first slip and fall, health-related quality of life and cost-effectiveness. Results A total of 4553 eligible NHS staff were randomised (2275 to the intervention arm and 2278 to the control arm). In total, 6743 slips were reported [2633 in the intervention group (mean 1.16 per participant, range 0–36 per participant) and 4110 in the control group (mean 1.80 per participant, range 0–83 per participant)]. There was a statistically significant reduction in the slip rate in the intervention group relative to the control group (incidence rate ratio 0.63, 95% confidence interval 0.57 to 0.70; p < 0.001). Statistically significant reductions were observed in falls from a slip (incidence rate ratio 0.51, 95% confidence interval 0.28 to 0.92; p = 0.03), the proportion of participants who reported a slip (odds ratio 0.58, 95% confidence interval 0.50 to 0.66; p < 0.001) or fall (odds ratio 0.73, 95% confidence interval 0.54 to 0.99; p = 0.04) and the time to first slip (hazard ratio 0.73, 95% confidence interval 0.67 to 0.80; p < 0.001). Half of the intervention participants wore the shoes all the time at work. Incremental cost per quality-adjusted life-year in the base case was £38,900 from the NHS perspective and –£60,400 (i.e. cost saving) from the societal perspective. Limitations This was an unblinded trial in which outcome data were participant self-reported, which may have led to inaccuracies in the reported slip data. Exposure to the trial footwear was lower than hoped. Conclusions The offer and provision of 5-star, GRIP-rated footwear reduced slips in the workplace, was acceptable to participants and could be cost-effective. Future work Replication of the study within other settings may be required to evaluate the clinical effectiveness and cost-effectiveness in other environments settings, such as catering and factories. Trial registration Current Controlled Trials ISRCTN33051393. Funding This project was funded by the National Institute for Health Research (NIHR) Public Health Research programme and will be published in full in Public Health Research; Vol. 9, No. 3. See the NIHR Public Journals Library website for further project information. The Health and Safety Executive provided some research costs

    A framework for monitoring the safety of water services: from measurements to security

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    The sustainable developments goals (SDGs) introduced monitoring of drinking water quality to the international development agenda. At present, Escherichia coli are the primary measure by which we evaluate the safety of drinking water from an infectious disease perspective. Here, we propose and apply a framework to reflect on the purposes of and approaches to monitoring drinking water safety. To deliver SDG 6.1, universal access to safe drinking water, a new approach to monitoring is needed. At present, we rely heavily on single measures of E. coli contamination to meet a normative definition of safety. Achieving and sustaining universal access to safe drinking water will require monitoring that can inform decision making on whether services are managed to ensure safety and security of access

    Quantitative Analysis of Lipid Droplet Fusion: Inefficient Steady State Fusion but Rapid Stimulation by Chemical Fusogens

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    Lipid droplets (LDs) are dynamic cytoplasmic organelles containing neutral lipids and bounded by a phospholipid monolayer. Previous studies have suggested that LDs can undergo constitutive homotypic fusion, a process linked to the inhibitory effects of fatty acids on glucose transporter trafficking. Using strict quantitative criteria for LD fusion together with refined light microscopic methods and real-time analysis, we now show that LDs in diverse cell types show low constitutive fusogenic activity under normal growth conditions. To investigate the possible modulation of LD fusion, we screened for agents that can trigger fusion. A number of pharmacological agents caused homotypic fusion of lipid droplets in a variety of cell types. This provided a novel cell system to study rapid regulated fusion between homotypic phospholipid monolayers. LD fusion involved an initial step in which the two adjacent membranes became continuous (<10 s), followed by the slower merging (100 s) of the neutral lipid cores to produce a single spherical LD. These fusion events were accompanied by changes to the LD surface organization. Measurements of LDs undergoing homotypic fusion showed that fused LDs maintained their initial volume, with a corresponding decrease in surface area suggesting rapid removal of membrane from the fused LD. This study provides estimates for the level of constitutive LD fusion in cells and questions the role of LD fusion in vivo. In addition, it highlights the extent of LD restructuring which occurs when homotypic LD fusion is triggered in a variety of cell types

    Movements of Diadromous Fish in Large Unregulated Tropical Rivers Inferred from Geochemical Tracers

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    Patterns of migration and habitat use in diadromous fishes can be highly variable among individuals. Most investigations into diadromous movement patterns have been restricted to populations in regulated rivers, and little information exists for those in unregulated catchments. We quantified movements of migratory barramundi Lates calcarifer (Bloch) in two large unregulated rivers in northern Australia using both elemental (Sr/Ba) and isotope (87Sr/86Sr) ratios in aragonitic ear stones, or otoliths. Chemical life history profiles indicated significant individual variation in habitat use, particularly among chemically distinct freshwater habitats within a catchment. A global zoning algorithm was used to quantify distinct changes in chemical signatures across profiles. This algorithm identified between 2 and 6 distinct chemical habitats in individual profiles, indicating variable movement among habitats. Profiles of 87Sr/86Sr ratios were notably distinct among individuals, with highly radiogenic values recorded in some otoliths. This variation suggested that fish made full use of habitats across the entire catchment basin. Our results show that unrestricted movement among freshwater habitats is an important component of diadromous life histories for populations in unregulated systems
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