5,133 research outputs found
Lithium abundances in nearby FGK dwarf and subgiant stars: internal destruction, Galactic chemical evolution, and exoplanets
We derive atmospheric parameters and lithium abundances for 671 stars and
include our measurements in a literature compilation of 1381 dwarf and subgiant
stars. First, a "lithium desert" in the effective temperature (Teff) versus
lithium abundance (A_Li) plane is observed such that no stars with Teff~6075 K
and A_Li~1.8 are found. We speculate that most of the stars on the low A_Li
side of the desert have experienced a short-lived period of severe surface
lithium destruction as main-sequence or subgiant stars. Next, we search for
differences in the lithium content of thin-disk and thick-disk stars, but we
find that internal processes have erased from the stellar photospheres their
possibly different histories of lithium enrichment. Nevertheless, we note that
the maximum lithium abundance of thick-disk stars is nearly constant from
[Fe/H]=-1.0 to -0.1, at a value that is similar to that measured in very
metal-poor halo stars (A_Li~2.2). Finally, differences in the lithium abundance
distribution of known planet-host stars relative to otherwise ordinary stars
appear when restricting the samples to narrow ranges of Teff or mass, but they
are fully explained by age and metallicity biases. We confirm the lack of a
connection between low lithium abundance and planets. However, we find that no
low A_Li planet-hosts are found in the desert Teff window. Provided that subtle
sample biases are not responsible for this observation, this suggests that the
presence of gas giant planets inhibit the mechanism responsible for the lithium
desert.Comment: ApJ, in press. Complete Tables 1 and 3 are available upon reques
Lesbian and bisexual women's human rights, sexual rights and sexual citizenship: negotiating sexual health in England.
Lesbian and bisexual women's sexual health is neglected in much Government policy and practice in England and Wales. This paper examines lesbian and bisexual women's negotiation of sexual health, drawing on findings from a small research project. Themes explored include invisibility and lack of information, influences on decision-making and sexual activities and experiences of services and barriers to sexual healthcare. Key issues of importance in this respect are homophobic and heterosexist social contexts. Drawing on understandings of lesbian, gay and bisexual human rights, sexual rights and sexual citizenship, it is argued that these are useful lenses through which to examine and address lesbian and bisexual women's sexual health and related inequalities
Automated longwall guidance and control vertical control subsystem, volume 2
Software documentation and a computer program listing for a horizon control of a longwall shearer are presented
Development and testing of a risk indexing framework to determine field-scale critical source areas of faecal bacteria on grassland.
This paper draws on lessons from a UK case study in the management of diffuse microbial pollution from grassland farm systems in the Taw catchment, south west England. We report on the development and preliminary testing of a field-scale faecal indicator organism risk indexing tool (FIORIT). This tool aims to prioritise those fields most vulnerable in terms of their risk of contributing FIOs to water. FIORIT risk indices were related to recorded microbial water quality parameters (faecal coliforms [FC] and intestinal enterococci [IE]) to provide a concurrent on-farm evaluation of the tool. There was a significant upward trend in Log[FC] and Log[IE] values with FIORIT risk score classification (r2 =0.87 and 0.70, respectively and P<0.01 for both FIOs). The FIORIT was then applied to 162 representative grassland fields through different seasons for ten farms in the case study catchment to determine the distribution of on-farm spatial and temporal risk. The high risk fields made up only a small proportion (1%, 2%, 2% and 3% for winter, spring, summer and autumn, respectively) of the total number of fields assessed (and less than 10% of the total area), but the likelihood of the hydrological connection of high FIO source areas to receiving watercourses makes them a priority for mitigation efforts. The FIORIT provides a preliminary and evolving mechanism through which we can combine risk assessment with risk communication to end-users and provides a framework for prioritising future empirical research. Continued testing of FIORIT across different geographical areas under both low and high flow conditions is now needed to initiate its long term development into a robust indexing tool
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Developing workplace menopause policies: four reasons why, and how
Menopause is increasingly â if finally â being acknowledged as an important workplace issue. Five experts from different fields discuss the social, business, legal and ethical cases for improving support at work for women transitioning through the menopause, and explain how to start and sustain the conversation with employers.
Menopause â when a woman stops having periods for good â is currently receiving an increasing amount of attention. Celebrities including Kirsty Wark, Davina McCall, Gillian Anderson, Jenny Eclair, Meg Mathews, Carol Vorderman and Cynthia Nixon have shared their experiences of this natural, and yet often taboo, mid-life transition with the wider world. Also noticeable is a groundswell among employers across a variety of sectors that are acknowledging the significant effects menopause symptoms
Cost of survivorship care and adherence to screening-aligning the priorities of health care systems and survivors.
Childhood cancer survivors (CCS) experience significant morbidity due to treatment- related late effects and benefit from late-effects surveillance. Adherence to screening recommendations is suboptimal. Survivorship care programs often struggle with resource limitations and may benefit from understanding institution-level financial outcomes associated with patient adherence to justify programmatic development and growth. The purpose of this study is to examine how CCS adherence to screening recommendations relates to the cost of care, insurance status, and institution-level financial outcomes. A retrospective chart review of 286 patients, followed in a structured survivorship program, assessed adherence to the Children\u27s Oncology Group follow-up guidelines by comparing recommended versus performed screening procedures for each patient. Procedure cost estimates were based on insurance status. Institutional profit margins and profit opportunity loss were calculated. Bivariate statistics tested adherent versus nonadherent subgroup differences on cost variables. A generalized linear model predicted the likelihood of adherence based on cost of recommended procedures, controlling for age, gender, race, and insurance. Adherence to recommended surveillance procedures was 50.2%. Nonadherence was associated with higher costs of recommended screening procedures compared to the adherent group estimates (1,211.44). Failure to perform the recommended tests resulted in no difference in reimbursement to the health system between groups (1,211.08). For the nonadherent group, this represented 311,850 in lost profit opportunity due to nonadherence in this subgroup. In the final model, nonadherence was related to higher cost of recommended procedures (p \u3c .0001), older age at visit (p = .04), Black race (p = .02), and government-sponsored insurance (p = .03). Understanding institutional financial outcomes related to patient adherence may help inform survivorship care programs and resource allocation. Potential financial burden to patients associated with complex care recommendations is also warranted
A combinatorial approach to knot recognition
This is a report on our ongoing research on a combinatorial approach to knot
recognition, using coloring of knots by certain algebraic objects called
quandles. The aim of the paper is to summarize the mathematical theory of knot
coloring in a compact, accessible manner, and to show how to use it for
computational purposes. In particular, we address how to determine colorability
of a knot, and propose to use SAT solving to search for colorings. The
computational complexity of the problem, both in theory and in our
implementation, is discussed. In the last part, we explain how coloring can be
utilized in knot recognition
Full-Polarization Observations of OH Masers in Massive Star-Forming Regions: I. Data
We present full-polarization VLBA maps of the ground-state, main-line, 2 Pi
3/2, J = 3/2 OH masers in 18 Galactic massive star-forming regions. This is the
first large polarization survey of interstellar hydroxyl masers at VLBI
resolution. A total of 184 Zeeman pairs are identified, and the corresponding
magnetic field strengths are indicated. We also present spectra of the NH3
emission or absorption in these star-forming regions. Analysis of these data
will be presented in a companion paper.Comment: 111 pages, including 42 figures and 21 tables, to appear in ApJ
Data on the Effect of In Utero Exposure to Polycyclic Aromatic Hydrocarbons on Genome-Wide Patterns of DNA Methylation in Lung Tissues
Data in this article depict patterns of methylation in lung tissues obtained from the offspring of B6129SF1/J dams and 129S1/SvImJ sires exposed in utero to benzo[a]pyrene (BaP) or dibenzo[def,p]chrysene (DBC) as compared to non-exposed offspring. Genome-wide methylation of lung tumors in adult offspring was determined using methylated DNA immunoprecipitation (MeDIP) with the NimbleGen mouse DNA methylation CpG island array. This data article refers to the research article âDNA methylation in lung tissues of mouse offspring exposed in utero to polycyclic aromatic hydrocarbons,â in which comprehensive data interpretation and analysis are provided
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