36 research outputs found

    Hydrogen Balmer Line Broadening in Solar and Stellar Flares

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    The broadening of the hydrogen lines during flares is thought to result from increased charge (electron, proton) density in the flare chromosphere. However, disagreements between theory and modeling prescriptions have precluded an accurate diagnostic of the degree of ionization and compression resulting from flare heating in the chromosphere. To resolve this issue, we have incorporated the unified theory of electric pressure broadening of the hydrogen lines into the non-LTE radiative transfer code RH. This broadening prescription produces a much more realistic spectrum of the quiescent, A0 star Vega compared to the analytic approximations used as a damping parameter in the Voigt profiles. We test recent radiative-hydrodynamic (RHD) simulations of the atmospheric response to high nonthermal electron beam fluxes with the new broadening prescription and find that the Balmer lines are over-broadened at the densest times in the simulations. Adding many simultaneously heated and cooling model loops as a "multithread" model improves the agreement with the observations. We revisit the three-component phenomenological flare model of the YZ CMi Megaflare using recent and new RHD models. The evolution of the broadening, line flux ratios, and continuum flux ratios are well-reproduced by a multithread model with high-flux nonthermal electron beam heating, an extended decay phase model, and a "hot spot" atmosphere heated by an ultrarelativistic electron beam with reasonable filling factors: 0.1%, 1%, and 0.1% of the visible stellar hemisphere, respectively. The new modeling motivates future work to understand the origin of the extended gradual phase emission.Comment: 31 pages, 13 figures, 2 tables, accepted for publication in the Astrophysical Journa

    Food insecurity increases Risk of Depression and Anxiety Among Women in Senegal Living With Diabetes and/or Hypertension

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    Food insecurity affects close to half the population of Senegal, West Africa, a country simultaneously affected by the ongoing global diabetes pandemic. Diabetes and food insecurity are associated with adverse mental health, yet research exploring the relationship between chronic physical illness, food insecurity, and mental illness in Senegal is currently lacking. The objective of this study was to investigate the association between food insecurity and depression and anxiety, separately, in Senegalese women living with diabetes and hypertension. Food insecurity was measured using the Household Food Insecurity Access Scale. Occurrence of depression and anxiety symptoms was assessed using the Modified Hopkins Symptoms Checklist Survey (HSCL-25). A sensitivity analysis examining the relationship between food insecurity and depression and anxiety was performed by comparing two previously validated cutoff values (1.75 and 2.25) on the HSCL-25. Most participants (83%) had some level of food insecurity. More than 80% of the sample were depressed or anxious using 1.75 as the cutoff, while 42 and 60% were depressed or anxious, respectively, using 2.25 as the cutoff. Food insecurity increased relative risk for depression (RRR: 1.40, 95% CI: 1.05-1.31, 1.75 as cutoff; RRR: 1.06, 95% CI: 0.99-1.14, 2.25 as cutoff) and anxiety (RRR: 1.17, 95% CI: 1.05-1.31, 1.75 as cutoff; RRR: 1.11, 95% CI: 1.04-1.19, 2.25 as cutoff). These findings demonstrate that among populations suffering from diabetes and hypertension, food insecurity is a modifiable risk factor for depression and anxiety and a potential intervention target in this setting

    The Vermicelli and Capellini Handling Tests: Simple quantitative measures of dexterous forepaw function in rats and mice

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    Previous characterizations of rodent eating behavior have revealed that they use coordinated forepaw movements to manipulate food pieces. We have extended upon this work to develop a simple quantitative measure of forepaw dexterity that is sensitive to lateralized impairments and age-dependent changes. Rodents learn skillful forepaw and digit movements to manage thin pasta pieces, which they eagerly consume. We have previously described methods for quantifying vermicelli handling in rats and showed that the measures are very sensitive to forelimb impairments resulting from unilateral ischemic lesions, middle cerebral artery occlusions and unilateral striatal dopamine depletion [Allred, R.P., Adkins, D.L., Woodlee, M.T., Husbands, L.C., Maldonado M.A., Kane, J.R., Schallert, T. & Jones, T.A. The Vermicelli Handling Test: a simple quantitative measure of dexterous forepaw function in rats. J. Neurosci. Methods 170, 229-244 (2008)]. Here we present a more detailed protocol for this test in rats and compare it with a newly developed version for mice, the Capellini Handling Test. Rats and mice are videotaped while handling short lengths of uncooked vermicelli or capellini pasta, respectively, with a camera positioned to optimize the view of paw movements. Slow motion video playback allows for the identification of forepaw adjustments, defined as any distinct removal and replacement of the paw, or of any number of digits, on the pasta piece after eating commences. Forepaw adjustments per piece are averaged over trials per each testing session. Repeated testing permits sensitive quantitative analysis of changes in forepaw dexterity over time. Protocols for pre-testing habituation and handling practice, as well as procedures for characterizing atypical handling patterns, are described. Because rats and mice perform the pasta handling tests slightly differently, species-specific differences in administration and scoring of these tests are highlighted. All animal use was in accordance with protocols approved by the University of Texas at Austin Animal Care and Use Committee

    Food insecurity increases risk of depression and anxiety among women in Senegal living with diabetes and/or hypertension

    Get PDF
    Food insecurity affects close to half the population of Senegal, West Africa, a country simultaneously affected by the ongoing global diabetes pandemic. Diabetes and food insecurity are associated with adverse mental health, yet research exploring the relationship between chronic physical illness, food insecurity, and mental illness in Senegal is currently lacking. The objective of this study was to investigate the association between food insecurity and depression and anxiety, separately, in Senegalese women living with diabetes and hypertension. Food insecurity was measured using the Household Food Insecurity Access Scale. Occurrence of depression and anxiety symptoms was assessed using the Modified Hopkins Symptoms Checklist Survey (HSCL‑25). A sensitivity analysis examining the relationship between food insecurity and depression and anxiety was performed by comparing two previously validated cutoff values (1.75 and 2.25) on the HSCL‑25. Most participants (83%) had some level of food insecurity. More than 80% of the sample were depressed or anxious using 1.75 as the cutoff, while 42 and 60% were depressed or anxious, respectively, using 2.25 as the cutoff. Food insecurity increased relative risk for depression (RRR: 1.40, 95% CI: 1.05‑1.31, 1.75 as cutoff; RRR: 1.06, 95% CI: 0.99‑1.14, 2.25 as cutoff) and anxiety (RRR: 1.17, 95% CI: 1.05‑1.31, 1.75 as cutoff; RRR: 1.11, 95% CI: 1.04‑1.19, 2.25 as cutoff). These findings demonstrate that among populations suffering from diabetes and hypertension, food insecurity is a modifiable risk factor for depression and anxiety and a potential intervention target in this setting

    A global experiment on motivating social distancing during the COVID-19 pandemic

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    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e., a controlling message) compared with no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared with the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing. Controlled motivation was associated with more defiance and less long-term behavioral intention to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges

    A global experiment on motivating social distancing during the COVID-19 pandemic

    Get PDF
    Finding communication strategies that effectively motivate social distancing continues to be a global public health priority during the COVID-19 pandemic. This cross-country, preregistered experiment (n = 25,718 from 89 countries) tested hypotheses concerning generalizable positive and negative outcomes of social distancing messages that promoted personal agency and reflective choices (i.e., an autonomy-supportive message) or were restrictive and shaming (i.e. a controlling message) compared to no message at all. Results partially supported experimental hypotheses in that the controlling message increased controlled motivation (a poorly-internalized form of motivation relying on shame, guilt, and fear of social consequences) relative to no message. On the other hand, the autonomy-supportive message lowered feelings of defiance compared to the controlling message, but the controlling message did not differ from receiving no message at all. Unexpectedly, messages did not influence autonomous motivation (a highly-internalized form of motivation relying on one’s core values) or behavioral intentions. Results supported hypothesized associations between people’s existing autonomous and controlled motivations and self-reported behavioral intentions to engage in social distancing: Controlled motivation was associated with more defiance and less long-term behavioral intentions to engage in social distancing, whereas autonomous motivation was associated with less defiance and more short- and long-term intentions to social distance. Overall, this work highlights the potential harm of using shaming and pressuring language in public health communication, with implications for the current and future global health challenges
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