1,451 research outputs found

    El futuro de la empresa meteorológica

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    Climate change modulates the stratospheric volcanic sulfate aerosol lifecycle and radiative forcing from tropical eruptions.

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    Explosive volcanic eruptions affect climate, but how climate change affects the stratospheric volcanic sulfate aerosol lifecycle and radiative forcing remains unexplored. We combine an eruptive column model with an aerosol-climate model to show that the stratospheric aerosol optical depth perturbation from frequent moderate-magnitude tropical eruptions (e.g. Nabro 2011) will be reduced by 75% in a high-end warming scenario compared to today, a consequence of future tropopause height rise and unchanged eruptive column height. In contrast, global-mean radiative forcing, stratospheric warming and surface cooling from infrequent large-magnitude tropical eruptions (e.g. Mt. Pinatubo 1991) will be exacerbated by 30%, 52 and 15% in the future, respectively. These changes are driven by an aerosol size decrease, mainly caused by the acceleration of the Brewer-Dobson circulation, and an increase in eruptive column height. Quantifying changes in both eruptive column dynamics and aerosol lifecycle is therefore key to assessing the climate response to future eruptions

    py4DSTEM: a software package for multimodal analysis of four-dimensional scanning transmission electron microscopy datasets

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    Scanning transmission electron microscopy (STEM) allows for imaging, diffraction, and spectroscopy of materials on length scales ranging from microns to atoms. By using a high-speed, direct electron detector, it is now possible to record a full 2D image of the diffracted electron beam at each probe position, typically a 2D grid of probe positions. These 4D-STEM datasets are rich in information, including signatures of the local structure, orientation, deformation, electromagnetic fields and other sample-dependent properties. However, extracting this information requires complex analysis pipelines, from data wrangling to calibration to analysis to visualization, all while maintaining robustness against imaging distortions and artifacts. In this paper, we present py4DSTEM, an analysis toolkit for measuring material properties from 4D-STEM datasets, written in the Python language and released with an open source license. We describe the algorithmic steps for dataset calibration and various 4D-STEM property measurements in detail, and present results from several experimental datasets. We have also implemented a simple and universal file format appropriate for electron microscopy data in py4DSTEM, which uses the open source HDF5 standard. We hope this tool will benefit the research community, helps to move the developing standards for data and computational methods in electron microscopy, and invite the community to contribute to this ongoing, fully open-source project

    Am I getting an accurate picture: a tool to assess clinical handover in remote settings?

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    BACKGROUND: Good clinical handover is critical to safe medical care. Little research has investigated handover in rural settings. In a remote setting where nurses and medical students give telephone handover to an aeromedical retrieval service, we developed a tool by which the receiving clinician might assess the handover; and investigated factors impacting on the reliability and validity of that assessment. METHODS: Researchers consulted with clinicians to develop an assessment tool, based on the ISBAR handover framework, combining validity evidence and the existing literature. The tool was applied 'live' by receiving clinicians and from recorded handovers by academic assessors. The tool's performance was analysed using generalisability theory. Receiving clinicians and assessors provided feedback. RESULTS: Reliability for assessing a call was good (G = 0.73 with 4 assessments). The scale had a single factor structure with good internal consistency (Cronbach's alpha = 0.8). The group mean for the global score for nurses and students was 2.30 (SD 0.85) out of a maximum 3.0, with no difference between these sub-groups. CONCLUSIONS: We have developed and evaluated a tool to assess high-stakes handover in a remote setting. It showed good reliability and was easy for working clinicians to use. Further investigation and use is warranted beyond this setting

    The Extratropical Transition of Tropical Cyclones: Forecast Challenges, Current Understanding, and Future Directions

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    A significant number of tropical cyclones move into the midlatitudes and transform into extratropical cyclones. This process is generally referred to as extratropical transition (ET). During ET a cyclone frequently produces intense rainfall and strong winds and has increased forward motion, so that such systems pose a serious threat to land and maritime activities. Changes in the structure of a system as it evolves from a tropical to an extratropical cyclone during ET necessitate changes in forecast strategies. In this paper a brief climatology of ET is given and the challenges associated with forecasting extratropical transition are described in terms of the forecast variables (track, intensity, surface winds, precipitation) and their impacts (flooding, bush fires, ocean response). The problems associated with the numerical prediction of ET are discussed. A comprehensive review of the current understanding of the processes involved in ET is presented. Classifications of extratropical transition are described and potential vorticity thinking is presented as an aid to understanding ET. Further sections discuss the interaction between a tropical cyclone and the midlatitude environment, the role of latent heat release, convection and the underlying surface in ET, the structural changes due to frontogenesis, the mechanisms responsible for precipitation, and the energy budget during ET. Finally, a summary of the future directions for research into ET is given

    Vertical variance analysis of geomagnetic disturbance during solar cycle 23

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    The geomagnetic field consists of temporal variations induced primarily by the variations in the solar wind and embedded interplanetary magnetic field. 34 stations across the Earth have been categorized in this paper on the basis of their geomagnetic disturbance during solar cycle 23 (1997-2008). The Vertical Variance (VV) disturbance quantifier has been used to develop such profile. The latitude profile of geomagnetic disturbance has been found to exhibit a typical 'Knee' behaviour, with the fluctuation content seen to rise sharply beyond this critical latitude determined near 52° latitude. The increasing trend in geomagnetic fluctuation content however is seen to end around the auroral oval beyond where abrupt variations has been observed indicating the transition from closed to open magnetic field lines. The physical mechanism behind this trend has also been explored. The VV analysis of geomagnetic disturbance has revealed prominent features of solar wind – magnetosphere coupling

    Vertical variance analysis of geomagnetic disturbance during solar cycle 23

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    300-309The geomagnetic field consists of temporal variations induced primarily by the variations in the solar wind and embedded interplanetary magnetic field. 34 stations across the Earth have been categorized in this paper on the basis of their geomagnetic disturbance during solar cycle 23 (1997-2008). The Vertical Variance (VV) disturbance quantifier has been used to develop such profile. The latitude profile of geomagnetic disturbance has been found to exhibit a typical ‘Knee’ behaviour, with the fluctuation content seen to rise sharply beyond this critical latitude determined near 52° latitude. The increasing trend in geomagnetic fluctuation content however is seen to end around the auroral oval beyond where abrupt variations has been observed indicating the transition from closed to open magnetic field lines. The physical mechanism behind this trend has also been explored. The VV analysis of geomagnetic disturbance has revealed prominent features of solar wind – magnetosphere coupling

    Football fans in training: the development and optimization of an intervention delivered through professional sports clubs to help men lose weight, become more active and adopt healthier eating habits

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    <p>Background: The prevalence of obesity in men is rising, but they are less likely than women to engage in existing weight management programmes. The potential of professional sports club settings to engage men in health promotion activities is being increasingly recognised. This paper describes the development and optimization of the Football Fans in Training (FFIT) programme, which aims to help overweight men (many of them football supporters) lose weight through becoming more active and adopting healthier eating habits.</p> <p>Methods: The MRC Framework for the design and evaluation of complex interventions was used to guide programme development in two phases. In Phase 1, a multidisciplinary working group developed the pilot programme (p-FFIT) and used a scoping review to summarize previous research and identify the target population. Phase 2 involved a process evaluation of p-FFIT in 11 Scottish Premier League (SPL) clubs. Participant and coach feedback, focus group discussions and interviews explored the utility/acceptability of programme components and suggestions for changes. Programme session observations identified examples of good practice and problems/issues with delivery. Together, these findings informed redevelopment of the optimized programme (FFIT), whose components were mapped onto specific behaviour change techniques using an evidence-based taxonomy.</p> <p>Results: p-FFIT comprised 12, weekly, gender-sensitised, group-based weight management classroom and ‘pitch-side’ physical activity sessions. These in-stadia sessions were complemented by an incremental, pedometer-based walking programme. p-FFIT was targeted at men aged 35-65 years with body mass index ≥ 27 kg/m2. Phase 2 demonstrated that participants in p-FFIT were enthusiastic about both the classroom and physical activity components, and valued the camaraderie and peer-support offered by the programme. Coaches appreciated the simplicity of the key healthy eating and physical activity messages. Suggestions for improvements that were incorporated into the optimized FFIT programme included: more varied in-stadia physical activity with football-related components; post-programme weight management support (emails and a reunion session); and additional training for coaches in SMART goal setting and the pedometer-based walking programme.</p> <p>Conclusions: The Football Fans in Training programme is highly acceptable to participants and SPL coaches, and is appropriate for evaluation in a randomised controlled trial.</p&gt

    Molecular characterization and clinical outcomes of pancreatic neuroendocrine tumors (pNENs) harboring PAK4-NAMPT alterations

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    Background: The mTOR inhibitor, Everolimus (EVE), is FDA-approved for the treatment of advanced PNENs on the basis of delay of progression. The RADIANT-3 trial showed an increase in PFS from 4.6 to 11 months compared to placebo with an ORR of only 5%. Prior studies suggest that targeting the aberrant expression of mTOR regulators p21 activated kinase 4 (PAK4) and nicotinamide adenine dinucleotide biosynthesis enzyme nicotinamide phosphoribosyltransferase (NAMPT) in PNENs sensitizes these tumors to EVE. To further qualify these observations, we queried a large real-world dataset of PNENs, characterizing the molecular and immune landscapes, as well as the clinical outcomes associated with aberrant PAK4 and NAMPT expression. Methods: 294 cases of PNENs were analyzed using Next Generation Sequencing (NextSeq) and Whole Exome and Whole Transcriptome Sequencing (NovaSeq) at Caris Life Sciences (Phoenix, AZ). For our analyses, we stratified our study cohort into four groups based on the median expression of PAK4 and NAMPT: PAK4-low/NAMPT-low, PAK4-low/ NAMPT-high, PAK4-high/NAMPT-low and PAK4-high/NAMPT-high. Significance was determined using chi-square, Fisher-Exact or Mann-Whitney U, and p-values were adjusted for multiple comparisons (q , 0.05). Results: High prevalence of mutations in PTEN (10.71% vs 1.18%; p \u3c 0.05, q \u3e 0.05), a tumor suppressor of the mTOR pathway and high expression of genes activated in response to mTOR activation such as SLC2A1 (3.07-fold), PFKP (3.32-fold), SCD (2.70-fold), MVK (2.92-fold) and G6PD (2.58-fold) were observed in PAK4-high/NAMPT-high compared to the PAK4-low/NAMPTlow tumors (all q , 0.05). A congruent enrichment of PI3K/AKT/mTOR and glycolysis pathways by single-sample gene set enrichment analysis was observed in these tumors (all q , 0.05). When querying the immune landscape, we observed enrichment in inflammatory response, IL6/JAK/STAT3, IL2/STAT5 signaling pathways and immune checkpoint genes such as PDCD1 (5.14-fold), CD274 (2.84-fold), PDCD1LG2 (2.44-fold), CD80 (3.00-fold), CD86 (2.82-fold), IDO1 (1.92-fold), LAG3 (3.09-fold), HAVCR2 (2.66-fold) and CTLA4 (4.49-fold) in the PAK4-high/NAMPT-high tumors (all q,0.05). Immune cell infiltration estimates revealed an increase in Neutrophils, NK cells and Tregs in the PAK4-high/NAMPT-high tumors (p \u3c 0.05, q \u3e 0.05). Conclusions: Our study demonstrates that PAK4-high/NAMPT-high PNENs are associated with distinct molecular and immune profiles. While the dual blockade of PAK4 and NAMPT has been reported to enhance the efficacy of EVE in PNENs, whether such a blockade would enhance the efficacy of immunotherapeutics warrants further investigation
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