1,279 research outputs found

    Investigation of foamed metals for application on space capsules annual report, 29 jun. 1963 - 15 aug. 1964

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    Foamed metal development for space capsules - brazing, variable density beam, thermal testing, mechanical tests, and machinin

    Surveyor spacecraft system - Surveyor 6 flight performance Final report

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    Surveyor 6 spacecraft flight performance characteristics, including data on television equipment, alpha scattering experiment, and powered flight translatio

    Spectral Evolution of an Earth-Like Planet

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    We have developed a characterization of the geological evolution of the Earths atmosphere and surface in order to model the observable spectra of an Earth-like planet through its geological history. These calculations are designed to guide the interpretation of an observed spectrum of such a planet by future instruments that will characterize exoplanets. Our models focus on spectral features that either imply habitability or are required for habitability. These features are generated by H2O, CO2, CH4, O2, O3, N2O, and vegetation-like surface albedos. We chose six geological epochs to characterize. These epochs exhibit a wide range in abundance for these molecules, ranging from a CO2 rich early atmosphere, to a CO2/CH4-rich atmosphere around 2 billion years ago to a present-day atmosphere. We analyzed the spectra to quantify the strength of each important spectral feature in both the visible and thermal infrared spectral regions, and the resolutions required to unambiguously observe the features for each epoch. We find a wide range of spectral resolutions required for observing the different features. For example, H2O and O3 can be observed with relatively low resolution, while O2 and N2O require higher resolution. We also find that the inclusion of clouds in our models significantly affects both the strengths and resolutions required to observe all spectral features.Comment: 34 pages, 24 fig, pdf, ApJ, TB

    Assessing satisfaction with social care services among black and minority ethnic and white British carers of stroke survivors in England

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    Overall satisfaction levels with social care are usually high but lower levels have been reported among black and minority ethnic (BME) service users in England. Reasons for this are poorly understood. This qualitative study therefore explored satisfaction with services among informal carer participants from five different ethnic groups. Fifty-seven carers (black Caribbean, black African, Asian Indian, Asian Pakistani and white British) were recruited from voluntary sector organisations and a local hospital in England, and took part in semi-structured interviews using cognitive interviewing and the critical incident technique. Interviews took place from summer 2013 to spring 2014. Thematic analysis of the interviews showed that participants often struggled to identify specific ‘incidents’, especially satisfactory ones. When describing satisfactory services, participants talked mostly about specific individuals and relationships. Unsatisfactory experiences centred on services overall. When rating services using cognitive interviewing, explicit comparisons with expectations or experiences with other services were common. Highest satisfaction ratings tended to be justified by positive personal characteristics among practitioners, trust and relationships. Lower level ratings were mostly explained by inconsistency in services, insufficient or poor care. Lowest level ratings were rare. Overall, few differences between ethnic groups were identified, although white British participants rated services higher overall giving more top ratings. White British participants also frequently took a more overall view of services, highlighting some concerns but still giving top ratings, while South Asian carers in particular focused on negative aspects of services. Together these methods provide insight into what participants mean by satisfactory and unsatisfactory services. Cognitive interviewing was more challenging for some BME participants, possibly a reflection of the meaningfulness of the concept of service satisfaction to them. Future research should include comparisons between BME and white participants’ understanding of the most positive parts of satisfaction scales and should focus on dissatisfied participants

    Qualitative focus group study investigating experiences of accessing and engaging with social care services: perspectives of carers from diverse ethnic groups caring for stroke survivors

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    OBJECTIVES: Informal carers, often family members, play a vital role in supporting stroke survivors with post-stroke disability. As populations age, numbers of carers overall and those from minority ethnic groups in particular, are rising. Carers from all ethnic groups, but especially those from black and minority ethnic groups frequently fail to access support services, making understanding their experiences important. The study therefore explored the experiences of carers of stroke survivors aged 45+ years from 5 ethnic groups in accessing and receiving social care services after hospital discharge. DESIGN: This qualitative study used 7 recorded focus groups with informal carers of stroke survivors. Data were analysed thematically focusing on similarities and differences between ethnic groups. SETTING: Carers were recruited from voluntary sector organisations supporting carers, stroke survivors and black and minority ethnic groups in the UK. PARTICIPANTS: 41 carers from 5 ethnic groups (Asian Indian, Asian Pakistani, black African, black Caribbean, white British) participated in the focus groups. RESULTS: Several interconnected themes were identified including: the service gap between hospital discharge and home; carers as the best person to care and cultural aspects of caring and using services. Many themes were common to all the included ethnic groups but some related to specific groups. CONCLUSIONS: Across ethnic groups there were many similarities in the experiences of people caring for stroke survivors with complex, long-term care needs. Accessing services demands effort and persistence on carers' part. If carers believe services are unsatisfactory or that they, rather than formal services, should be providing support for stroke survivors, they are unlikely to persist in their efforts. Cultural and language differences add to the challenges black and minority ethnic group carers face

    Characterizing the genetic basis of copper toxicity in Drosophila reveals a complex pattern of allelic, regulatory, and behavioral variation

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    A range of heavy metals are required for normal cell function and homeostasis. However, the anthropogenic release of metal compounds into soil and water sources presents a pervasive health threat. Copper is one of many heavy metals that negatively impacts diverse organisms at a global scale. Using a combination of quantitative trait locus (QTL) mapping and RNA sequencing in the Drosophila Synthetic Population Resource, we demonstrate that resistance to the toxic effects of ingested copper in D. melanogaster is genetically complex and influenced by allelic and expression variation at multiple loci. QTL mapping identified several QTL that account for a substantial fraction of heritability. Additionally, we find that copper resistance is impacted by variation in behavioral avoidance of copper and may be subject to life-stage specific regulation. Gene expression analysis further demonstrated that resistant and sensitive strains are characterized by unique expression patterns. Several of the candidate genes identified via QTL mapping and RNAseq have known copper-specific functions (e.g., Ccs, Sod3, CG11825), and others are involved in the regulation of other heavy metals (e.g., Catsup, whd). We validated several of these candidate genes with RNAi suggesting they contribute to variation in adult copper resistance. Our study illuminates the interconnected roles that allelic and expression variation, organism life stage, and behavior play in copper resistance, allowing a deeper understanding of the diverse mechanisms through which metal pollution can negatively impact organisms

    Exploring the Potential Role of Family History of Hypertension on Racial Differences in Sympathetic Vascular Transduction

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    The prevalence of hypertension in Non-Hispanic Black (BL) men surpasses all other racial groups. Our laboratory has previously demonstrated exaggerated vasoconstrictor and blood pressure (BP) responses to spontaneous bursts of muscle sympathetic nerve activity (MSNA; sympathetic vascular transduction) in young, healthy BL men compared to their Non-Hispanic White (WH) counterparts. Because a family history of hypertension (FHH) further compounds cardiovascular risk, we wanted to begin to explore the potential impact of a positive (+) FHH on sympathetic vascular transduction. Whether a +FHH influences sympathetic vascular transduction in WH and/or BL men remains unknown. PURPOSE: To begin to explore if +FHH influences sympathetic vascular transduction within and between racial groups. METHODS: 22 men, nine with a +FHH (4 BL men) and 13 without a FHH (-FHH; 6 BL men) were recruited. Beat-to-beat BP (Finometer), femoral artery blood flow (Doppler ultrasound), and MSNA were measured during a 20-minute quiet rest. The mean BP and leg vascular conductance (LVC; blood flow/mean BP) responses to spontaneous bursts of MSNA were quantified via a signal averaging technique. RESULTS: Resting heart rate, BP, and MSNA were not significantly different between groups (all p\u3e0.05). As previously demonstrated by our laboratory, the BL men exhibited an augmented sympathetic vascular transduction compared to the WH men (e.g., peak BP response, WH men: Δ4.1±0.3, BL men: Δ5.6±0.7 mmHg, p=0.04). When accounting for FHH within the groups, the peak BP (WH +FHH: Δ4.4±0.6 vs. WH -FHH: Δ3.8±0.4 mmHg, p=0.4) and nadir LVC responses (WH +FHH: Δ-0.5±0.07 vs. WH -FHH: Δ-0.5±0.09 ml·min-¹·mmHg-¹, p=0.7) were not significantly different between WH men +FHH and WH men –FHH. Likewise, the BL men +FHH exhibited similar peak BP (BL +FHH: Δ6.2±0.7 vs. BL -FHH: Δ5.3±1.1 mmHg, p=0.5) and nadir LVC (BL +FHH: Δ-1.1±0.44 vs. BL -FHH: Δ-0.6±0.10 ml·min-¹·mmHg-¹, p=0.2) responses to bursts of MSNA compared to the BL men –FHH. CONCLUSION: These preliminary findings do not support a role for +FHH in augmented sympathetic vascular transduction, therefore suggesting that racial differences in sympathetic vascular transduction are independent of FHH
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