11,365 research outputs found

    Modelling Dust Evolution in Galaxies with a Multiphase, Inhomogeneous ISM

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    We develop a model of dust evolution in a multiphase, inhomogeneous ISM including dust growth and destruction processes. The physical conditions for grain evolution are taken from hydrodynamical simulations of giant molecular clouds in a Milky Way-like spiral galaxy. We improve the treatment of dust growth by accretion in the ISM to investigate the role of the temperature-dependent sticking coefficient and ion-grain interactions. From detailed observational data on the gas-phase Si abundances [Si/H]_{gas} measured in the local Galaxy, we derive a relation between the average [Si/H]_{gas} and the local gas density n(H) which we use as a critical constraint for the models. This relation requires a sticking coefficient that decreases with the gas temperature. The synthetic relation constructed from the spatial dust distribution reproduces the slope of -0.5 of the observed relation in cold clouds. This slope is steeper than that for the warm medium and is explained by the dust growth. We find that it occurs for all adopted values of the minimum grain size a_{min} from 1 to 5nm. For the classical cut-off of a_{min}=5 nm, the ion-grain interactions result in longer growth timescales and higher [Si/H]_{gas} than the observed values. For a_{min} below 3 nm, the ion-grain interactions enhance the growth rates, steepen the slope of [Si/H]_{gas}-n(H) relation and provide a better match to observations. The rates of dust re-formation in the ISM by far exceed the rates of dust production by stellar sources as expected from simple evolution models. After the cycle of matter in and out of dust reaches a steady state, the dust growth balances the destruction operating on similar timescales of 350 Myr.Comment: 17 pages, 11 figures, accepted to Ap

    Convicts and coolies : rethinking indentured labour in the nineteenth century

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    This article seeks to shift the frame of analysis within which discussions of Indian indentured migration take place. It argues that colonial discourses and practices of indenture are best understood not with regard to the common historiographical framework of whether it was 'a new system of slavery', but in the context of colonial innovations in incarceration and confinement. The article shows how Indian experiences of and knowledge about transportation overseas to penal settlements informed in important ways both their own understandings and representations of migration and the colonial practices associated with the recruitment of indentured labour. In detailing the connections between two supposedly different labour regimes, it thus brings a further layer of complexity to debates around their supposed distinctions

    Investigation of critical slowing down in a bistable S-SEED

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    A simulation of S-SEED switching based upon experimental data is developed that includes the effect of critical slowing down. The simulation's accuracy is demonstrated by close agreement with the results from experimental S-SEED switching. The simulation is subsequently used to understand how the phenomenon of critical slowing down applies to switching of an S-SEED and how the effect on photonic analog-to-digital (A/D) converter performance may be minimized.B. A. Clare, K. A. Corbett, K. J. Grant, P. B. Atanackovic, W. Marwood and J. Munc

    “My Purpose is to Assist”: How ChatGPT Can Push Liberal Arts Institutions to Think Critically About Themselves

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    Since its release, ChatGPT, a chatbot specialized in writing content and answering questions in response to user prompts, has posed an unclear threat to liberal arts institutions. Can it serve as an effective tool for cheating? Can its responses replace work done in the liberal arts? This thesis argues that ChatGPT’s limitations—particularly its inability to think critically—prevent it from replacing real liberal arts work, which involves questioning, critique, and re-examination. If anything, this thesis suggests, ChatGPT can push liberal arts institutions to better promote critical thinking by serving as a litmus test for liberal arts-level work

    Direct Nitrous Oxide Emissions From Tropical And Sub-Tropical Agricultural Systems : A Review and Modelling of Emission Factors

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    We acknowledge the financial support from the CGIAR Research Programs on Climate Change, Agriculture and Food Security (CCAFS). Grant ref. n. P25.Peer reviewedPublisher PD

    A Cereal Chemist's Quick Guide to Genetics, Plant Breeding and BioIT

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    This book is intended as a guide for cereal chemists in quality testing laboratories and grain product development companies, to help them in their understanding of fundamental genetics, functional genomics and other concepts of relevance during their interactions with crop breeding programs. Consequently the emphasis is on quick definitions of terms and concepts, assuming that the expertise of the reader is predominantly in another field.Established and supported under the Australian Government’s Cooperative Research Centre Progra

    Functional status in ICU survivors and out of hospital outcomes: a cohort study

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    OBJECTIVES: Functional status at hospital discharge may be a risk factor for adverse events among survivors of critical illness. We sought to examine the association between functional status at hospital discharge in survivors of critical care and risk of 90-day all-cause mortality after hospital discharge. DESIGN: Single-center retrospective cohort study. SETTING: Academic Medical Center. PATIENTS: Ten thousand three hundred forty-three adults who received critical care from 1997 to 2011 and survived hospitalization. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: The exposure of interest was functional status determined at hospital discharge by a licensed physical therapist and rated based on qualitative categories adapted from the Functional Independence Measure. The main outcome was 90-day post hospital discharge all-cause mortality. A categorical risk-prediction score was derived and validated based on a logistic regression model of the function grades for each assessment. In an adjusted logistic regression model, the lowest quartile of functional status at hospital discharge was associated with an increased odds of 90-day postdischarge mortality compared with patients with independent functional status (odds ratio, 7.63 [95% CI, 3.83-15.22; p < 0.001]). In patients who had at least 7 days of physical therapy treatment prior to hospital discharge (n = 2,293), the adjusted odds of 90-day postdischarge mortality in patients with marked improvement in functional status at discharge was 64% less than patients with no change in functional status (odds ratio, 0.36 [95% CI, 0.24-0.53]; p < 0.001). CONCLUSIONS: Lower functional status at hospital discharge in survivors of critical illness is associated with increased postdischarge mortality. Furthermore, patients whose functional status improves before discharge have decreased odds of postdischarge mortality.L30 TR001257 - NCATS NIH HH

    Dementia primary prevention policies and strategies and their local implementation: a scoping review using England as a case study

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    This is the author accepted manuscript. The final version is available from IOS Press via the DOI in this record.Background: Understanding policy context and how policy is implemented at the local and clinical level is an important precursor to developing preventive strategies focusing on dementia risk reduction in primary healthcare settings. Objective: Using England as a case study, we review policies and strategies relevant to dementia prevention from the national to local level and how these are translated into primary healthcare services. Methods: We conducted a scoping review covering: (a) identification of national, regional and local policies and strategies that include dementia prevention; (b) identification of national guidelines for implementing dementia prevention at the clinical level; and (c) evaluation of the implementation of these at the clinical level. Results: Dementia prevention is addressed in national policy, and this filters through to regional and local levels. Focus on dementia prevention is limited and variable. Reference to modifiable risk factors is associated with other non-communicable diseases, placing less emphasis on factors more dementia specific. Evidence of implementation of dementia prevention policies at the clinical level is limited and inconsistent. Available evidence suggests messages about dementia prevention may best be delivered through primary healthcare services such as the National Health Service (NHS) Health Check. Conclusion: The limitations identified in this review could be addressed through development of a national policy focused specifically on dementia prevention. This could provide a platform for increasing knowledge and understanding among the general population and healthcare professionals. It would be important for such a policy to cover the full range of modifiable risk factors relevant to dementia.This work was supported by the following grant: Centre for Research Excellence in Promoting Cognitive Health and Preventing Cognitive Decline with Chief Investigator Professor Kaarin Anstey. Funder’s number: APP 1100579

    The proqol-21: A revised version of the professional quality of life (ProQOL) scale based on Rasch analysis

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    The Professional Quality of Life scale is a measure intended to provide practitioners and researchers with an indication of a caring professional’s compassion satisfaction, burnout, and secondary traumatic stress. While this measure has been used extensively in nursing research, owing to the relevancy of patient-care associated satisfaction and fatigue within this profession, information regarding the construct validity of this measure is less well represented in the literature. We examined the construct validity of the Professional Quality of Life scale using a Rasch analysis procedure on each of its three scales, as a means of substantiating their measurement adequacy. Responses on the Professional Quality of Life scale from 1615 registered nurses (age x̅ = 46.48 years, SD = 11.78) were analysed. While support for the measurement adequacy (invariance, person/item fit, and unidimensionality) of the compassion satisfaction scale was found, the burnout and secondary traumatic stress scales did not demonstrate adequate measurement properties. We instead present an alternative measurement model of these subscales, involving items from each, to form a robust measure of compassion fatigue, and provide recoding, scoring, and normed scores for both measures. Our findings indicate that use of the Professional Quality of Life scale’s burnout and secondary traumatic stress scales may require caution, while our revised compassion satisfaction and fatigue scales provide robust measurement options for practitioners and researchers
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