474 research outputs found
First HARPSpol discoveries of magnetic fields in massive stars
In the framework of the Magnetism in Massive Stars (MiMeS) project, a
HARPSpol Large Program at the 3.6m-ESO telescope has recently started to
collect high-resolution spectropolarimetric data of a large number of Southern
massive OB stars in the field of the Galaxy and in many young clusters and
associations. In this Letter, we report on the first discoveries of magnetic
fields in two massive stars with HARPSpol - HD 130807 and HD 122451, and
confirm the presence of a magnetic field at the surface of HD 105382 that was
previously observed with a low spectral resolution device. The longitudinal
magnetic field measurements are strongly varying for HD 130807 from -100
G to 700 G. Those of HD 122451 and HD 105382 are less variable with
values ranging from -40 to -80 G, and from -300 to -600 G,
respectively. The discovery and confirmation of three new magnetic massive
stars, including at least two He-weak stars, is an important contribution to
one of the MiMeS objectives: the understanding of origin of magnetic fields in
massive stars and their impacts on stellar structure and evolution.Comment: 4 pages, 2 figures, accepted for publication in A&A Lette
The Science Case for an Extended Spitzer Mission
Although the final observations of the Spitzer Warm Mission are currently
scheduled for March 2019, it can continue operations through the end of the
decade with no loss of photometric precision. As we will show, there is a
strong science case for extending the current Warm Mission to December 2020.
Spitzer has already made major impacts in the fields of exoplanets (including
microlensing events), characterizing near Earth objects, enhancing our
knowledge of nearby stars and brown dwarfs, understanding the properties and
structure of our Milky Way galaxy, and deep wide-field extragalactic surveys to
study galaxy birth and evolution. By extending Spitzer through 2020, it can
continue to make ground-breaking discoveries in those fields, and provide
crucial support to the NASA flagship missions JWST and WFIRST, as well as the
upcoming TESS mission, and it will complement ground-based observations by LSST
and the new large telescopes of the next decade. This scientific program
addresses NASA's Science Mission Directive's objectives in astrophysics, which
include discovering how the universe works, exploring how it began and evolved,
and searching for life on planets around other stars.Comment: 75 pages. See page 3 for Table of Contents and page 4 for Executive
Summar
Carina OB Stars: X-ray Signatures of Wind Shocks and Magnetic Fields
The Chandra Carina Complex contains 200 known O- and B type stars. The
Chandra survey detected 68 of the 70 O stars and 61 of 127 known B0-B3 stars.
We have assembled a publicly available optical/X-ray database to identify OB
stars that depart from the canonical Lx/Lbol relation, or whose average X-ray
temperatures exceed 1 keV. Among the single O stars with high kT we identify
two candidate magnetically confined wind shock sources: Tr16-22, O8.5 V, and LS
1865, O8.5 V((f)). The O4 III(fc) star HD 93250 exhibits strong, hard, variable
X-rays, suggesting it may be a massive binary with a period of >30 days. The
visual O2 If* binary HD 93129A shows soft 0.6 keV and hard 1.9 keV emission
components, suggesting embedded wind shocks close to the O2 If* Aa primary, and
colliding wind shocks between Aa and Ab. Of the 11 known O-type spectroscopic
binaries, the long orbital-period systems HD 93343, HD 93403 and QZ Car have
higher shock temperatures than short-period systems such as HD 93205 and FO 15.
Although the X-rays from most B stars may be produced in the coronae of unseen,
low-mass pre-main-sequence companions, a dozen B stars with high Lx cannot be
explained by a distribution of unseen companions. One of these, SS73 24 in the
Treasure Chest cluster, is a new candidate Herbig Be star.Comment: To be published in a special issue of the Astrophysical Journal
Supplement on the Chandra Carina Complex Projec
Improving Information on Maternal Medication Use by Linking Prescription Data to Congenital Anomaly Registers: A EUROmediCAT Study
Research on associations between medication use during pregnancy and congenital anomalies is significative for assessing the safe use of a medicine in pregnancy. Congenital anomaly (CA) registries do not have optimal information on medicine exposure, in contrast to prescription databases. Linkage of prescription databases to the CA registries is a potentially effective method of obtaining accurate information on medicine use in pregnancies and the risk of congenital anomalies. We linked data from primary care and prescription databases to five European Surveillance of Congenital Anomalies (EUROCAT) CA registries. The linkage was evaluated by looking at linkage rate, characteristics of linked and non-linked cases, first trimester exposure rates for six groups of medicines according to the prescription data and information on medication use registered in the CA databases, and agreement of exposure. Of the 52,619 cases registered in the CA databases, 26,552 could be linked. The linkage rate varied between registries over time and by type of birth. The first trimester exposure rates and the agreements between the databases varied for the different medicine groups. Information on anti-epileptic drugs and insulins and analogue medicine use recorded by CA registries was of good quality. For selective serotonin reuptake inhibitors, anti-asthmatics, antibacterials for systemic use, and gonadotropins and other ovulation stimulants, the recorded information was less complete. Linkage of primary care or prescription databases to CA registries improved the quality of information on maternal use of medicines in pregnancy, especially for medicine groups that are less fully registered in CA registries
Toward optimal implementation of cancer prevention and control programs in public health: A study protocol on mis-implementation
Abstract Background Much of the cancer burden in the USA is preventable, through application of existing knowledge. State-level funders and public health practitioners are in ideal positions to affect programs and policies related to cancer control. Mis-implementation refers to ending effective programs and policies prematurely or continuing ineffective ones. Greater attention to mis-implementation should lead to use of effective interventions and more efficient expenditure of resources, which in the long term, will lead to more positive cancer outcomes. Methods This is a three-phase study that takes a comprehensive approach, leading to the elucidation of tactics for addressing mis-implementation. Phase 1: We assess the extent to which mis-implementation is occurring among state cancer control programs in public health. This initial phase will involve a survey of 800 practitioners representing all states. The programs represented will span the full continuum of cancer control, from primary prevention to survivorship. Phase 2: Using data from phase 1 to identify organizations in which mis-implementation is particularly high or low, the team will conduct eight comparative case studies to get a richer understanding of mis-implementation and to understand contextual differences. These case studies will highlight lessons learned about mis-implementation and identify hypothesized drivers. Phase 3: Agent-based modeling will be used to identify dynamic interactions between individual capacity, organizational capacity, use of evidence, funding, and external factors driving mis-implementation. The team will then translate and disseminate findings from phases 1 to 3 to practitioners and practice-related stakeholders to support the reduction of mis-implementation. Discussion This study is innovative and significant because it will (1) be the first to refine and further develop reliable and valid measures of mis-implementation of public health programs; (2) bring together a strong, transdisciplinary team with significant expertise in practice-based research; (3) use agent-based modeling to address cancer control implementation; and (4) use a participatory, evidence-based, stakeholder-driven approach that will identify key leverage points for addressing mis-implementation among state public health programs. This research is expected to provide replicable computational simulation models that can identify leverage points and public health system dynamics to reduce mis-implementation in cancer control and may be of interest to other health areas
Phase I and pharmacokinetic study of irinotecan in combination with R115777, a farnesyl protein transferase inhibitor
The aims of this study were to determine the maximum-tolerated dose (MTD), toxicity profile, and pharmacokinetics of irinotecan given with oral R115777 (tipifarnib), a farnesyl protein transferase inhibitor. Patients were treated with escalating doses of irinotecan with interval-modulated dosing of R115777 (continuously or on days 1-14, and repeated every 21 days). In total, 35 patients were entered onto the trial for a median duration of treatment of 43 days (range, 5-224 days). Neutropenia and thrombocytopenia were the dose-limiting toxicities; other side effects were mostly mild. The MTD was established at R115777 300 mg b.i.d. for 14 consecutive days with irinotecan 350 mg m-2 given every 3 weeks starting on day 1. Three patients had a partial response and 14 had stable disease. In the continuous schedule, the area under the curves of irinotecan and its active metabolite SN-38 were 20.0% (P = 0.004) and 38.0% (P < 0.001) increased by R115777, respectively. Intermittent dosing of R115777 at a dose of 300 mg b.i.d. for 14 days every 3 weeks is the recommended dose of R115777 in combination with the recommended single-agent irinotecan dose of 350 mg m-2
Reporting to Improve Reproducibility and Facilitate Validity Assessment for Healthcare Database Studies V1.0.
PURPOSE: Defining a study population and creating an analytic dataset from longitudinal healthcare databases involves many decisions. Our objective was to catalogue scientific decisions underpinning study execution that should be reported to facilitate replication and enable assessment of validity of studies conducted in large healthcare databases. METHODS: We reviewed key investigator decisions required to operate a sample of macros and software tools designed to create and analyze analytic cohorts from longitudinal streams of healthcare data. A panel of academic, regulatory, and industry experts in healthcare database analytics discussed and added to this list. CONCLUSION: Evidence generated from large healthcare encounter and reimbursement databases is increasingly being sought by decision-makers. Varied terminology is used around the world for the same concepts. Agreeing on terminology and which parameters from a large catalogue are the most essential to report for replicable research would improve transparency and facilitate assessment of validity. At a minimum, reporting for a database study should provide clarity regarding operational definitions for key temporal anchors and their relation to each other when creating the analytic dataset, accompanied by an attrition table and a design diagram. A substantial improvement in reproducibility, rigor and confidence in real world evidence generated from healthcare databases could be achieved with greater transparency about operational study parameters used to create analytic datasets from longitudinal healthcare databases
The Heritability of Aptitude and Exceptional Talent Across Different Domains in Adolescents and Young Adults
The origin of individual differences in aptitude, defined as a domain-specific skill within the normal ability range, and talent, defined as a domain specific skill of exceptional quality, is under debate. The nature of the variation in aptitudes and exceptional talents across different domains was investigated in a population based twin sample. Self-report data from 1,685 twin pairs (12–24 years) were analyzed for Music, Arts, Writing, Language, Chess, Mathematics, Sports, Memory, and Knowledge. The influence of shared environment was small for both aptitude and talent. Additive and non-additive genetic effects explained the major part of the substantial familial clustering in the aptitude measures with heritability estimates ranging between .32 and .71. Heritability estimates for talents were higher and ranged between .50 and .92. In general, the genetic architecture for aptitude and talent was similar in men and women. Genetic factors contribute to a large extent to variation in aptitude and talent across different domains of intellectual, creative, and sports abilities
Cultural diversity teaching and issues of uncertainty: the findings of a qualitative study
BACKGROUND: There is considerable ambiguity in the subjective dimensions that comprise much of the relational dynamic of the clinical encounter. Comfort with this ambiguity, and recognition of the potential uncertainty of particular domains of medicine (e.g.--cultural factors of illness expression, value bias in diagnoses, etc) is an important facet of medical education. This paper begins by defining ambiguity and uncertainty as relevant to clinical practice. Studies have shown differing patterns of students' tolerance for ambiguity and uncertainty that appear to reflect extant attitudinal predispositions toward technology, objectivity, culture, value- and theory-ladeness, and the need for self-examination. This paper reports on those findings specifically related to the theme of uncertainty as relevant to teaching about cultural diversity. Its focus is to identify how and where the theme of certainty arose in the teaching and learning of cultural diversity, what were the attitudes toward this theme and topic, and how these attitudes and responses reflect and inform this area of medical pedagogy. METHODS: A semi-structured interview was undertaken with 61 stakeholders (including policymakers, diversity teachers, students and users). The data were analysed and themes identified. RESULTS: There were diverse views about what the term cultural diversity means and what should constitute the cultural diversity curriculum. There was a need to provide certainty in teaching cultural diversity with diversity teachers feeling under considerable pressure to provide information. Students discomfort with uncertainty was felt to drive cultural diversity teaching towards factual emphasis rather than reflection or taking a patient centred approach. CONCLUSION: Students and faculty may feel that cultural diversity teaching is more about how to avoid professional, medico-legal pitfalls, rather than improving the patient experience or the patient-physician relationship. There may be pressure to imbue cultural diversity issues with levels of objectivity and certainty representative of other aspects of the medical curriculum (e.g.--biochemistry). This may reflect a particular selection bias for students with a technocentric orientation. Inadvertently, medical education may enhance this bias through training effects, and accommodate disregard for subjectivity, over-reliance upon technology and thereby foster incorrect assumptions of objective certainty. We opine that it is important to teach students that technology cannot guarantee certainty, and that dealing with subjectivity, diversity, ambiguity and uncertainty is inseparable from the personal dimension of medicine as moral enterprise. Uncertainty is inherent in cultural diversity so this part of the curriculum provides an opportunity to address the issue as it relates to patient care
Quality of life utility values for hereditary haemochromatosis in Australia
Background: Hereditary hemochromatosis (HH) is a common autosomal recessive disorder amongst persons of northern European heritage. If untreated, iron accumulates in parenchymal tissues causing morbidity and mortality. As diagnosis often follows irreversible organ damage, screening programs have been suggested to increase early diagnosis. A lack of economic evidence has been cited as a barrier to establishing such a program. Previous analyses used poorly estimated utility values. This study sought to measure utilities directly from people with HH in Australia. Methods: Volunteers with HH were recruited to complete a web-based survey. Utility was assessed using the Assessment of Quality of Life 4D (AQOL-4D) instrument. Severity of HH was graded into four categories. Multivariable regression analysis was performed to identify parameters associated with HSUV. Results: Between November 2013 and November 2014, 221 people completed the survey. Increasing severity of HH was negatively associated with utility. Mean (standard deviation) utilities were 0.76 (0.21), 0.81 (0.18), 0.60 (0.27), and 0.50 (0.27) for categories 1-4 HH respectively. Lower mean utility was found for symptomatic participants (categories 3 and 4) compared with asymptomatic participants (0.583 v. 0.796). Self-reported HH-related symptoms were negatively associated with HSUV (r = -0.685). Conclusions: Symptomatic stages of HH and presence of multiple self-reported symptoms were associated with decreasing utility. Previous economic analyses have used higher utilities which likely resulted in underestimates of the cost effectiveness of HH interventions. The utilities reported in this paper are the most robust available, and will contribute to improving the validity of future economic models for HH
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