479 research outputs found

    Effects of Metallicity on the Rotation Rates of Massive Stars

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    Recent theoretical predictions for low metallicity massive stars predict that these stars should have drastically reduced equatorial winds (mass loss) while on the main sequence, and as such should retain most of their angular momentum. Observations of both the Be/(B+Be) ratio and the blue-to-red supergiant ratio appear to have a metallicity dependence that may be caused by high rotational velocities. We have analyzed 39 archival Hubble Space Telescope Imaging Spectrograph (STIS), high resolution, ultraviolet spectra of O-type stars in the Magellanic Clouds to determine their projected rotational velocities V sin i. Our methodology is based on a previous study of the projected rotational velocities of Galactic O-type stars using International Ultraviolet Explorer (IUE) Short Wavelength Prime (SWP) Camera high dispersion spectra, which resulted in a catalog of V sin i values for 177 O stars. Here we present complementary V sin i values for 21 Large Magellanic Cloud and 22 Small Magellanic Cloud O-type stars based on STIS and IUE UV spectroscopy. The distribution of V sin i values for O type stars in the Magellanic Clouds is compared to that of Galactic O type stars. Despite the theoretical predictions and indirect observational evidence for high rotation, the O type stars in the Magellanic Clouds do not appear to rotate faster than their Galactic counterparts.Comment: accepted by ApJ, to appear 20 December 2004 editio

    Bringing the Globe into Your Classroom

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    PSU students are keen to learn more about global issues, but not all are able to study abroad or travel. How can professors bring the globe into our classrooms? Presenters will share strategies they have used to create engaged and hands-on global experiences for students on campus and in the surrounding region. They will also share ideas for globally-oriented off-campus partnerships, internships, and student activities with organizations that have global missions or clients

    Association of Interparental Violence and Maternal Depression With Depression Among Adolescents at the Population and Individual Level

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    Importance: Parental intimate partner violence (IPV) and maternal depression are associated with increased risk of depression in children at the population level. However, it is not known whether having information about these experiences can accurately identify individual children at higher risk of depression. Objective: To examine the extent to which experiencing parental IPV and/or maternal depression before age 12 years is associated with depression at age 18 years at the population and individual level. Design, Setting, and Participants: This cohort study used data from the Avon Longitudinal Study of Parents and Children, a UK population-based birth cohort, which initially recruited pregnant mothers with estimated due dates in 1991 and 1992. Data used in this study were collected from 1991 to 2009. Data analysis was performed from February to March 2022. Exposures Mother-reported parental IPV was assessed on 8 occasions (child age, 1-11 years). Maternal depression was assessed via the Edinburgh Postnatal Depression Scale or by the mother taking medication for depression, as reported by the mother on 8 occasions (child age, 2-12 years). Main Outcomes and Measures: Depressive symptoms were measured with the Short Mood and Feelings Questionnaire (SMFQ) and Clinical Interview Schedule–Revised (CIS-R) when the child was aged 18 years. Binary indicators of a case of depression were derived the cutoff point of 11 points or above for the SMFQ and 12 points or above for the CIS-R. Results The study included 5029 children (2862 girls [56.9%]; 2167 boys [43.1%]) with a measure of depressive symptoms at age 18 years. IPV only was associated with a 24% (adjusted risk ratio, 1.24; 95% CI, 0.97-1.59) higher risk of depression at age 18 years, exposure to maternal depression only was associated with a 35% (adjusted risk ratio, 1.35; 95% CI, 1.11-1.64) higher risk, and exposure to both IPV and maternal depression was associated with a 68% (adjusted risk ratio, 1.68; 95% CI, 1.34-2.10) higher risk. At the individual level, the area under the receiver operating characteristic curve was 0.58 (95% CI, 0.55-0.60) for depression according to the SMFQ and 0.59 (95% CI, 0.55-0.62) for the CIS-R, indicating a 58% to 59% probability (ie, 8%-9% above chance) that a random participant with depression at age 18 years had been exposed to IPV and/or maternal depression compared with a random participant who did not have depression. Conclusions and Relevance: In this cohort study, parental IPV and maternal depression were associated with depression in adolescence at the population level. However, estimation of an individual developing depression in adolescence based only on information about IPV or maternal depression is poor. Screening children for maternal depression and IPV to target interventions to prevent adolescent depression will fail to identify many children who might benefit and may unnecessarily target many others who do not develop depression

    Child and family-focused interventions for child maltreatment and domestic abuse:Development of core outcome sets

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    BACKGROUND: The current evidence for child maltreatment (CM) and domestic violence and abuse (DVA) interventions is limited by the diversity of outcomes evaluated and the variety of measures used. The result is studies that are difficult to compare and lack focus on outcomes reflecting service user or provider priorities. OBJECTIVE: To develop core outcome sets (COSs) for evaluations of child and family-focused interventions for: (1) CM and (2) DVA. DESIGN: We conducted a two-stage consensus process. Stage 1: a long list of candidate outcomes across CM and DVA was developed through rapid systematic reviews of intervention studies, qualitative and grey literature; stakeholder workshops; survivor interviews. Stage 2: three-panel, three-round e-Delphi surveys for CM and DVA with consensus meetings to agree with the final COSs. PARTICIPANTS: 287 stakeholders participated in at least one stage of the process (ie, either CM or DVA COS development): workshops (n=76), two e-Delphi surveys (n=170) and consensus meetings (n=43). Stakeholders included CM and DVA survivors, practitioners, commissioners, policymakers and researchers. RESULTS: Stage 1 identified 335 outcomes categorised into 9 areas and 39 domains. Following stage 2, the final five outcomes included in the CM-COS were: child emotional health and well-being; child’s trusted relationships; feelings of safety; child abuse and neglect; service harms. The final five outcomes in the DVA-COS were: child emotional health and well-being; caregiver emotional health and well-being; family relationships; freedom to go about daily life; feelings of safety. CONCLUSIONS: We developed two COSs for CM and DVA with two common outcomes (child emotional health and well-being; feelings of safety). The COSs reflect shared priorities among service users, providers and researchers. Use of these COSs across trials and service evaluations for children and families affected by CM and DVA will make outcome selection more consistent and help harmonise research and practice

    Reject Analysis in Digital Radiography and Computed Tomography: A Belgian Imaging Department Case Study

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    Objective: Reject analysis is usually performed in digital radiography (DR) for quality assurance. Data for computed tomography (CT) rejects remains sparse. The aim of this study is to help provide a straightforward benchmark for reject analysis of both DR and CT. Materials and methods: This retrospective observational study included 107,277 DR and 20,659 CT during 18 months in a tertiary care center. Rejected acquisitions were retrieved by Dose Archiving and Communication System (DACS). The DR and CT reject analysis included reject rates, reasons for rejection and supplementary radiation dose associated with these rejects. Results: 8,904 rejected DR and 514 rejected CT were retrieved. The DR reject rate was 8.3% whereas the CT reject rate was 2.5%. The cumulative effective dose (ED) of DR rejects was 377.3 mSv while the cumulative ED of CT rejects was 1267.4 mSv. The major reason for rejects was positioning for both DR (61%) and CT (44%). Conclusion: This study helps constitute a simple reproducible method to analyze both DR and CT rejects simultaneously. Although CT rejects are less often monitored than DR rejects, the radiation dose associated with CT rejects is much higher, which emphasizes the need to systematically monitor both DR and CT rejects. Investigating the reasons and the most frequently rejected examinations gives an opportunity for improvement of imaging techniques in cooperation with technologists

    Family adversity and health characteristics associated with intimate partner violence in children and parents presenting to health care: a population-based birth cohort study in England

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    BACKGROUND: Little is known about the clinical characteristics of children and parents affected by intimate partner violence (IPV) presenting in health-care settings. We examined the associations between family adversities, health characteristics, and IPV in children and parents using linked electronic health records (EHRs) from primary and secondary care between 1 year before and 2 years after birth (the first 1000 days). We compared parental health problems in in children and parents with and without recorded IPV. METHODS: We developed a population-based birth cohort of children and parents (aged 14-60 years) in England, comprising linked EHRs from mother-child pairs (with no identified father) and mother-father-child triads. We followed the cohort across general practices (Clinical Practice Research Datalink GOLD), emergency departments, outpatient visits, hospital admissions, and mortality records. Family adversities included 33 clinical indicators of parental mental health problems, parental substance misuse, adverse family environments, and high-risk child maltreatment-related presentations. Parental health problems included 12 common comorbidities, ranging from diabetes and cardiovascular diseases to chronic pain or digestive diseases. We used adjusted and weighted logistic-regression models to estimate the probability of IPV (per 100 children and parents) associated with each adversity, and period prevalences of parental health problems associated with IPV. FINDINGS: We included 129 948 children and parents, comprising 95 290 (73·3%) mother-father-child triads and 34 658 (26·7%) mother-child pairs only between April 1, 2007, and Jan 29, 2020. An estimated 2689 (2·1%) of 129 948 children and parents (95% CI 2·0-2·3) had recorded IPV and 54 758 (41·2%; 41·5-42·2) had any family adversity between 1 year before and 2 years after birth. All family adversities were significantly associated with IPV. Most parents and children with IPV had recorded adversities (1612 [60·0%] of 2689) before their first IPV recording. The probability of IPV was 0·6 per 100 children and parents (95% CI 0·5-0·6) with no adversity, increasing to 4·4 per 100 children per parents (4·2-4·7) with one adversity, and up to 15·1 per 100 parents and children (13·6-16·5) with three of more adversities. Mothers with IPV had a significantly higher prevalence of both physical (73·4% vs 63·1%, odds ratio [OR] 1·6, 95% CI 1·4-1·8) and mental health problems (58·4% vs 22·2%, OR 4·9, 4·4-5·5) than mothers without IPV. Fathers with IPV had a higher prevalence of mental health problems (17·8% vs 7·1%, OR 2·8, 2·4-3·2) and similar prevalences of physical health problems than those without IPV (29·6% vs 32·4%, OR 0·9, 0·8-1·0). INTERPRETATION: Two in five of the children and parents presenting to health care had recorded parental mental health problems, parental substance misuse, adverse family environments, or high-risk presentations of maltreatment in the first 1000 days. One in 22 children and parents with family adversity also had recorded IPV before age 2 years. Primary and secondary care staff should safely ask about IPV when parents or children present with family adversity or health problems associated with IPV, and respond appropriately. FUNDING: NIHR Policy Research Programme

    Beyond Provenance: New Approaches to Interpreting the Chemistry of Archaeological Copper Alloys

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    For the last 180 years, scientists have been attempting to determine the ‘provenance’ (geological source) of the copper used in Bronze Age artefacts. However, despite advances in analytical technologies, the theoretical approach has remained virtually unchanged over this period, with the interpretative methodology only changing to accommodate the increasing capacity of computers. This book represents a concerted effort to think about the composition of Bronze Age metal as the product of human intentionality as well as of geology. It considers the trace element composition of the metal, the alloying elements, and the lead isotopic composition, showing how a combination of these aspects, along with archaeological context and typology, can reveal much more about the life history of such artefacts, expanding considerably upon the rather limited ambition of knowing where the ore was extracted. Beyond Provenance serves as a ‘how-to handbook’ for those wishing to look for evidence of human intentionality in the chemical patterning observed in bronzes

    Tomographic Separation of Composite Spectra. IX. The Massive Close Binary HD 115071

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    We present the first orbital elements for the massive close binary, HD 115071, a double-lined spectroscopic binary in a circular orbit with a period of 2.73135 +/- 0.00003 days. The orbital semiamplitudes indicate a mass ratio of M_2/M_1 = 0.58 +/- 0.02 and yet the stars have similar luminosities. We used a Doppler tomography algorithm to reconstruct the individual component optical spectra, and we applied well known criteria to arrive at classifications of O9.5 V and B0.2 III for the primary and secondary, respectively. We present models of the Hipparcos light curve of the ellipsoidal variations caused by the tidal distortion of the secondary, and the best fit model for a Roche-filling secondary occurs for an inclination of i = 48.7 +/- 2.1 degrees. The resulting masses are 11.6 +/- 1.1 and 6.7 +/- 0.7 solar masses for the primary and secondary, respectively, so that both stars are very overluminous for their mass. The system is one of only a few known semi-detached, Algol-type binaries that contain O-stars. We suggest that the binary has recently emerged from extensive mass transfer (possibly through a delayed contact and common envelope process).Comment: Submitted to Ap

    Quantifying interactions between accommodation and vergence in a binocularly normal population

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    AbstractStimulation of the accommodation system results in a response in the vergence system via accommodative vergence cross-link interactions, and stimulation of the vergence system results in an accommodation response via vergence accommodation cross-link interactions. Cross-link interactions are necessary in order to ensure simultaneous responses in the accommodation and vergence systems. The crosslink interactions are represented most comprehensively by the response AC/A (accommodative vergence) and CA/C (vergence accommodation) ratios, although the stimulus AC/A ratio is measured clinically, and the stimulus CA/C ratio is seldom measured in clinical practice. The present study aims to quantify both stimulus and response AC/A and CA/C ratios in a binocularly normal population, and determine the relationship between them. 25 Subjects (mean±SD age 21.0±1.9years) were recruited from the university population. A significant linear relationship was found between the stimulus and response ratios, for both AC/A (r2=0.96, p<0.001) and CA/C ratios (r2=0.40, p<0.05). Good agreement was found between the stimulus and response AC/A ratios (95% CI −0.06 to 0.24MA/D). Stimulus and response CA/C ratios are linearly related. Stimulus CA/C ratios were higher than response ratios at low values, and lower than response ratios at high values (95% CI −0.46 to 0.42D/MA). Agreement between stimulus and response CA/C ratios is poorer than that found for AC/A ratios due to increased variability in vergence responses when viewing the Gaussian blurred target. This study has shown that more work is needed to refine the methodology of CA/C ratio measurement
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