812 research outputs found

    Quantitative Three-Dimensional Basal Ice Roughness from Scanning Electron Microscopy (SEM)

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    A method for analyzing the three-dimensional surface roughness on the basal facets of polar ice crystals is presented. A functional form of backscattered electron intensity as a function of ice facet orientation is adapted for the use of the basal facet. Using the Gauss-Newton inversion within a Bayesian framework a three dimensional representation of rough surfaces are retrieved at roughly micrometer resolution. Following the development of new statistical measures allow for higher statistical confidence and the connection to a scaling growth mechanism for crystal development. In a collection of results from temperatures ranging from -29 degrees celsius to -35 degrees celsius shows the characteristic of basal roughening to follow crystalline symmetry and a scaling growth mechanism. These results point to a opportunity to use three-dimensional modeling to identify the growth mechanism in polar ice crystals found in cirrus clouds

    Memo: Opportunities for Philanthropic Response to the Coronavirus (COVID-19) Crisis

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    Funders reached out to The Bridgespan Group to better understand how they might respond quickly and effectively to COVID-19. In response, The Bridgespan Group drafted this memo to provide initial perspectives on where resources might be productively channeled. It is based on their experience supporting nonprofits and NGOs working in public health and funders active in global health and disaster recovery, and on conversations with experts working on the COVID-19 response. Their perspectives have been further shaped by their research on inequity in funding for organizations led by people of color. This is a rapidly changing environment, and they anticipate that these perspectives on philanthropic opportunities will evolve as the pandemic unfolds

    Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines

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    Since their discovery twenty year ago, transition region bright points (TRBPs) have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a TRBP, a coronal BP (CBP) and a blinker. We use time-series observations of the extreme ultraviolet emission lines of a wide range of temperature T (log T = 5.3 - 6.4) from the EUV imaging spectrometer (EIS) onboard the Hinode satellite. We present the EIS temperature maps and Doppler maps, which are compared with magnetograms from the Michelson Doppler Imager (MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker are <,25 km s−1^{-1}, which is typical of transient TR phenomena. The Dopper velocities of the CBP were found to be < 20 km s^{-1} with exception of those measured at log T = 6.2 where a distinct bi-directional jet is observed. From an EM loci analysis we find evidence of single and double isothermal components in the TRBP and CBP, respectively. TRBP and CBP loci curves are characterized by broad distributions suggesting the existence of unresolved structure. By comparing and contrasting the physical characteristics of the events we find the BP phenomena are an indication of multi-scaled self similarity, given similarities in both their underlying magnetic field configuration and evolution in relation to EUV flux changes. In contrast, the blinker phenomena and the TRBP are sufficiently dissimilar in their observed properties as to constitute different event classes. Our work indicates that the measurement of similar characteristics across multiple event types holds class-predictive power, and is a significant step towards automated solar atmospheric multi-class classification of unresolved transient EUV sources.Comment: 38 pages, 16 figure

    An evaluation of the feasibility and validity of a patient-administered malnutrition universal screening tool (‘MUST’) compared to healthcare professional screening in an inflammatory bowel disease (IBD) outpatient clinic

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    Malnutrition is common in inflammatory bowel disease (IBD) and is associated with poor health outcomes. Despite this, screening for malnutrition in the outpatient‐setting is not routine and research in the area is limited. The present study aimed to evaluate whether agreement between malnutrition screening completed by patients and healthcare professionals (HCPs) could be achieved by comparing patient self‐administered ‘MUST’ (‘MUST’‐P) with HCP administered ‘MUST’ (‘MUST’‐HCP) in a single tertiary IBD outpatient clinic

    High-intensity compared to moderate-intensity training for exercise initiation, enjoyment, adherence, and intentions: an intervention study

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    Background: Understanding exercise participation for overweight and obese adults is critical for preventing comorbid conditions. Group-based high-intensity functional training (HIFT) provides time-efficient aerobic and resistance exercise at self-selected intensity levels which can increase adherence; behavioral responses to HIFT are unknown. This study examined effects of HIFT as compared to moderate-intensity aerobic and resistance training (ART) on exercise initiation, enjoyment, adherence, and intentions. Methods: A stratified, randomized two-group pre-test posttest intervention was conducted for eight weeks in 2012 with analysis in 2013. Participants (n = 23) were stratified by median age (< or ≄ 28) and body mass index (BMI; < or ≄ 30.5). Participants were physically inactive with an average BMI of 31.1 ± 3.5 kg/m2, body fat percentage of 42.0 ± 7.4%, weight of 89.5 ± 14.2 kg, and ages 26.8 ± 5.9 years. Most participants were white, college educated, female, and married/engaged. Both groups completed 3 training sessions per week. The ART group completed 50 minutes of moderate aerobic exercise each session and full-body resistance training on two sessions per week. The HIFT group completed 60-minute sessions of CrossFitℱ with actual workouts ranging from 5–30 minutes. Participants completed baseline and posttest questionnaires indicating reasons for exercise initiation (baseline), exercise enjoyment, and exercise intentions (posttest). Adherence was defined as completing 90% of exercise sessions. Daily workout times were recorded. Results: Participants provided mostly intrinsic reasons for exercise initiation. Eighteen participants adhered (ART = 9, 81.8%; HIFT = 9, 75%). HIFT dropouts (p = .012) and ART participants (p = .009) reported lower baseline exercise enjoyment than HIFT participants, although ART participants improved enjoyment at posttest (p = .005). More HIFT participants planned to continue the same exercise than ART participants (p = .002). No significant changes in BMI or body composition were found. Workouts were shorter for HIFT than ART (p < .001). Conclusions: HIFT participants spent significantly less time exercising per week, yet were able to maintain exercise enjoyment and were more likely to intend to continue. High-intensity exercise options should be included in public health interventions

    Cognitive correlates of abnormal myelination in psychosis

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    Psychotic illness has consistently been associated with deficits in cognitive function and reduced white matter integrity in the brain. However, the link between white matter disruptions and deficits in cognitive domains remains poorly understood. We assessed cognitive performance and white matter myelin water fraction (MWF) using multicomponent driven equilibrium single pulse observation of T1 and T2 (mcDESPOT) in recent-onset psychosis patients and age-matched healthy controls (HC). Psychosis patients showed deficits in working memory, phonological and semantic fluency, general intelligence quotient and reduced MWF in the left temporal white matter compared to HC. MWF in the left inferior fronto-occipital fasciculus and inferior longitudinal fasciculus was positively associated with intelligence quotient and verbal fluency in patients, and fully mediated group differences in performance in both phonological and semantic verbal fluency. There was no association between working memory and MWF in the left temporal white matter. Negative symptoms demonstrated a negative association with MWF within the left inferior and superior longitudinal fasciculi. These findings indicate that psychosis-related deficits in distinct cognitive domains, such as verbal fluency and working memory, are not underpinned by a single common dysfunction in white matter connectivity

    Hybrid Computing for Interactive Datacenter Applications

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    Field-Programmable Gate Arrays (FPGAs) are more energy efficient and cost effective than CPUs for a wide variety of datacenter applications. Yet, for latency-sensitive and bursty workloads, this advantage can be difficult to harness due to high FPGA spin-up costs. We propose that a hybrid FPGA and CPU computing framework can harness the energy efficiency benefits of FPGAs for such workloads at reasonable cost. Our key insight is to use FPGAs for stable-state workload and CPUs for short-term workload bursts. Using this insight, we design Spork, a lightweight hybrid scheduler that can realize these energy efficiency and cost benefits in practice. Depending on the desired objective, Spork can trade off energy efficiency for cost reduction and vice versa. It is parameterized with key differences between FPGAs and CPUs in terms of power draw, performance, cost, and spin-up latency. We vary this parameter space and analyze various application and worker configurations on production and synthetic traces. Our evaluation of cloud workloads shows that energy-optimized Spork is not only more energy efficient but it is also cheaper than homogeneous platforms--for short application requests with tight deadlines, it is 1.53x more energy efficient and 2.14x cheaper than using only FPGAs. Relative to an idealized version of an existing cost-optimized hybrid scheduler, energy-optimized Spork provides 1.2-2.4x higher energy efficiency at comparable cost, while cost-optimized Spork provides 1.1-2x higher energy efficiency at 1.06-1.2x lower cost.Comment: 13 page
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