130 research outputs found
Seismic Signatures of the 12C({\alpha}, {\gamma})16O Reaction Rate in White Dwarf Models with Overshooting
We consider the combined effects that overshooting and the 12C({\alpha},
{\gamma})16O reaction rate have on variable white dwarf stellar models. We find
that carbon-oxygen white dwarf models continue to yield pulsation signatures of
the current experimental 12C({\alpha}, {\gamma})16O reaction rate probability
distribution function when overshooting is included in the evolution. These
signatures hold because the resonating mantle region, encompassing
\,0.2\,\Msun\ in a typical \,0.6\,\Msun\ white dwarf model,
still undergoes radiative helium burning during the evolution to a white dwarf.
Our specific models show two potential low-order adiabatic g-modes, and
, that signalize the 12C({\alpha}, {\gamma})16O reaction rate probability
distribution function. Both g-mode signatures induce average relative period
shifts of and for and
respectively. We find that is a trapped mode, and the period
signature is inversely proportional to the 12C({\alpha}, {\gamma})16O reaction
rate. The period signature generally separates the slower and faster
reaction rates, and has a maximum relative period shift of . We conclude that low-order g-mode periods from carbon-oxygen white
dwarfs may still serve as viable probes for the 12C({\alpha}, {\gamma})16O
reaction rate probability distribution function when overshooting is included
in the evolution.Comment: 18 pages, 10 total figures, 2 online interactive figures, zenodo data
set link included. Accepted to the Astrophysical Journa
The Role of Extracellular Vesicles in β-Cell Function and Viability: A Scoping Review
Extracellular vesicles (EVs) released by cells throughout the body have been implicated in diabetes pathogenesis. Understanding the role of EVs in regulation of β-cell function and viability may provide insights into diabetes etiology and may lead to the development of more effective screening and diagnostic tools to detect diabetes earlier and prevent disease progression. This review was conducted to determine what is known from the literature about the effect of EV crosstalk on pancreatic β-cell function and viability in the pathogenesis of diabetes mellitus, to perform a gap analysis for future research directions, and to discuss implications of available evidence for diabetes care. The literature search yielded 380 studies from which 31 studies were determined to meet eligibility criteria. The majority of studies had the disease context of autoimmunity in T1DM. The most commonly studied EV crosstalk dynamics involved localized EV-mediated communication between β-cells and other islet cells, or between β-cells and immune cells. Other organs and tissues secreting EVs that affect β-cells include skeletal muscle, hepatocytes, adipocytes, immune cells, bone marrow, vascular endothelium, and mesenchymal stem cells. Characterization of EV cargo molecules with regulatory effects in β-cells was conducted in 24 studies, with primary focus on microRNA cargo. Gaps identified included scarcity of evidence for the effect on β-cell function and viability of EVs from major metabolic organs/tissues such as muscle, liver, and adipose depots. Future research should address these gaps as well as characterize a broader range of EV cargo molecules and their activity in β-cells
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SHOCK INITIATION EXPERIMENTS ON THE HMX BASED EXPLOSIVE LX-10 WITH ASSOCIATED IGNITION AND GROWTH MODELING
Shock initiation experiments on the HMX based explosives LX-10 (95% HMX, 5% Viton by weight) and LX-07 (90% HMX, 10% Viton by weight) were performed to obtain in-situ pressure gauge data, run-distance-to-detonation thresholds, and Ignition and Growth modeling parameters. A 101 mm diameter propellant driven gas gun was utilized to initiate the explosive samples with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments and prior experiments on another HMX based explosive LX LX-04 (85% HMX, 15% Viton by weight) will be shown, discussed, and compared as a function of the binder content. This parameter set will provide additional information to ensure accurate code predictions for safety scenarios involving HMX explosives with different percent binder content additions
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LOW AMPLITUDE SINGLE AND MULTIPLE SHOCK INITIATION EXPERIMENTS AND MODELING OF LX-04
Shock initiation experiments were performed on the plastic bonded explosive (PBX) LX-04 (85% HMX, 15% Viton binder) using single and multiple low amplitude shocks to obtain pressure history data for use in Ignition and Growth reactive flow modeling parameterization. A 100 mm diameter propellant driven gas gun was utilized to initiate the LX-04 explosive charges containing manganin piezoresistive pressure gauge packages placed between explosive discs. In the single shock experiments, the run distances to detonation at three shock pressures showed agreement with previously published data above 3 GPa. Even longer run distances to detonation were measured using 80 mm long by 145 mm diameter LX-04 charges impacted by low velocity projectiles from a 155 mm diameter gun. The minimum shock pressure required to cause low levels of exothermic reaction were determined for these large LX-04 charge dimensions. Multiple shocks were generated as double shocks by using a flyer plate with two materials and as reflected shocks by placing a high impedance material at the rear of the explosive charge. In both cases, the first shock pressure was not high enough to cause detonation of LX-04, and the second shock pressure, which would have been sufficient to cause detonation if generated by a single shock, failed to cause detonation. Thus LX-04 exhibited shock desensitization over a range of 0.6 to 1.4 GPa. The higher shock pressure LX-04 model was extended to accurately simulate these lower pressure and multiple shock gauge records. The shock desensitization effects observed with multiple shock compressions were partially accounted for in the model by using a critical compression corresponding to a shock pressure of 1.2 GPa. This shock desensitization effect occurs at higher pressures than those of other HMX-based PBX's containing higher HMX percentages
Assessment of a self-reported Drinks Diary for the estimation of drinks intake by care home residents: Fluid Intake Study in the Elderly (FISE)
Objectives: We evaluated the accuracy of a newly developed self-completed Drinks Diary in care home residents and compared it with direct observation and fluid intake charts. Design: Observational study. Setting: Residential care homes in Norfolk, UK. Participants: 22 elderly people (18 women, mean age 86.6 years SD 8.6, 12 with MMSE scores <27). Measurements: Participants recorded their own drinks intake over 24 hours using the Drinks Diary while care staff used the homes’ usual fluid intake chart to record drinks intake. These records were compared with drinks intake assessed by researcher direct observation (reference method), during waking hours (6am to 10pm), while drinks taken from 10pm to 6am were self-reported and checked with staff. Results: Drinks intake assessed by the Drinks Diary was highly correlated with researcher direct observation (Pearson correlation coefficient r=0.93, p<0.001, mean difference -163ml/day) while few staff-completed fluid charts were returned and correlation was low (r=0.122, p=0.818, mean difference 702ml/day). The Drinks Diary classified 19 of 22 participants correctly as drinking enough or not using both the European Food Safety Authority and US recommendations. Conclusion: The Drinks Diary estimate of drinks intake was comparable with direct observation and more accurate (and reliably completed) than staff records. The Drinks Diary can provide a reliable estimate of drinks intake in elderly care home residents physically and cognitively able to complete it. It may be useful for researchers, care staff and practitioners needing to monitor drinks intake of elderly people, to help them avoid dehydration
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SHOCK INITIATION EXPERIMENTS ON PBX 9501 EXPLOSIVE AT PRESSURES BELOW 3 GPa WITH ASSOCIATED IGNITION AND GROWTH MODELING
Shock initiation experiments on the explosive PBX 9501 (95% HMX, 2.5% estane, and 2.5% nitroplasticizer by weight) were performed at pressures below 3 GPa to obtain in-situ pressure gauge data, run-distance-to-detonation thresholds, and Ignition and Growth modeling parameters. Propellant driven gas guns (101 mm and 155 mm) were utilized to initiate the PBX 9501 explosive with manganin piezoresistive pressure gauge packages placed between sample slices. The run-distance-to-detonation points on the Pop-plot for these experiments showed agreement with previously published data and Ignition and Growth modeling parameters were obtained with a good fit to the experimental data. This parameter set will allow accurate code predictions to be calculated for safety scenarios in the low-pressure regime (below 3 GPa) involving PBX 9501 explosive
Beyond the Insider—Outsider Perspective: The Study of Religion as a Study of Discourse Construction
This essay reflects on contemporary theorizing of religion which embodies an explicit critique of the imperial project, seeing that by most common consent the scholarly disciplinary field of religious studies (history of religion, phenomenology of religion, Religionswissenschaft) is a late nineteenth century invention that coincides with the emergence of anthropology and ethnography as epiphenomena of the colonial project (whether as Orientalism or as exoticism the Other is rendered manageable subjects). The scholarly study of religion is, therefore, simultaneously a study of the history of theory and concept formation, and the social, cultural, and political work performed by such study and theorizing. The metatheory of the study of religion is a main focus of the essay. Alongside that, the essay focuses more pointedly on the concept of discourse, and considers the extraordinary situation where the same methodological vocabulary that functions in religious studies also functions in critical theological studies, which relativizes the division of ‘insider’ and ‘outsider’ perspectives. Yet both are conventionally practised either in isolation from each other as distinct theoretical and disciplinary bounded/defined study fields, or—the other and almost direct opposite—religious studies being performed in the context of theological study, situated in and offered by theological faculties. An overview of recent debates in the field of religious studies serves to highlight the continued struggle to demarcate the boundaries between the study of religion and the study of theology—in some of the recent, very strident debates mainstream religious studies is labelled as nothing more than theology. This contribution, then, aims at a kind of metatheoretical reflection on the study of religion and theology both as discourses that serve mythmaking, identity formation, culturally strategic purposes. That is, from the discourse perspective that is proposed here, it is possible to move beyond the definitional divide between religious studies and theology—even beyond ‘religion’ itself—to focus on the mundanely material practices that constitute that which is called religion. In the way in which the terms are used it is clear that the terminologies themselves bear the imprint of historical social discourses that occasioned the rise of their use. This essay, then, is something of a metacritique of the language of the study of religion—beyond religion, and beyond the study of religion and theology
Negotiating sacred roles:a sociological exploration of priests who are mothers
In 1992, in a historic move, the Church of England voted to allow women's ordination to priesthood and in 1994 the first women priests started to be ordained. Despite much research interest, the experiences of priests who are mothers to dependent children have been minimally investigated. Based on in-depth interviews with seventeen mothers ordained in the Church, this paper will focus on how the sacred-profane boundary is managed. Priests who are mothers have a particular insight into the Church hierarchy as they symbolically straddle the competing discourses of sacred and profane. However, instead of reifying these binaries, the experiences of these women show how such dualisms are challenged and managed in everyday life. Indeed, in terms of experience, ritual, ministry and preaching, priests who are mothers are resisting, recasting and renegotiating sacred terrain in subtle and nuanced ways. Mothers thus not only negotiate the practical and sacramental demands placed on priests, but also illuminate how the sacred domain is regulated and constructed
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