13 research outputs found

    Quantal calculations on the rotational excitation of NH(_3) and OH in collisions with H(_2)

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    Results are presented for quantal close coupled calculations of the rotational excitation of NH(_3) and OH in collisions with both ortho and para-H(_2). For the latter, these are the first calculations to include the rotational structure of the H(_2) molecule, whilst for the former, previous NH(_3) - ortho-H(_2) calculations have been subject to subsidiary approximations. The results from the NH3-H2 calculation show substantial qualitative changes in the cross-sections when ground state ortho-H(_2) (j = 1) replaces ground state para-H(_2) (j = 0) as the collision partner. In particular, cross-sections which were very small for NH(_3) - para-H(_2) collisions can be of a comparable magnitude with the other rotationally inelastic cross-sections for NH(_3) - ortho-H(_2) collisions. The changes in cross-sections are discussed in relation to the collisional pumping scheme for an astrophysical maser in the (jk = 33) inversion lines. From the OH-H(_2) calculations it is found that the propensities towards preferential excitation of a given component of the A doublets are reduced in strength when ortho-H(_2) replaces ground state para-H(_2) as the collision partner, similarly when (j = 2) para-H(_2) replaces ground state para-H(_2) the propensities are weakened. In both cases, the results are discussed in the context of crossed beam measurements at energies of 605cm(^-1)(NH(_3)-H(_2)) and 680cm(^-1) (OH-H(_2)). It is found that discrepancies between the experimental results and theoretical calculations for ground state para-H(_2) collisions can be explained, at least in part, by the neglect of the (j > 0) H(_2) rotational states in the latter

    Automatic Redshift Determination by use of Principal Component Analysis --- I: Fundamentals

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    With the advent of very large redshift surveys of tens to hundreds of thousands of galaxies reliable techniques for automatically determining galaxy redshifts are becoming increasingly important. The most common technique currently in common use is the cross-correlation of a galactic spectrum with a set of templates. This series of papers presents a new method based on Principal Component Analysis. The method generalizes the cross-correlation approach by replacing the individual templates by a simultaneous linear combination of orthogonal templates. This effectively eliminates the mismatch between templates and data and provides for the possibility of better error estimates. In this paper, the first of a series, the basic mathematics are presented along with a simple demonstration of the application.Comment: 23 pages, 9 Figures, minor revisions, accepted for publication in Astrophysical Journa

    A genome-wide association study in Europeans and South Asians identifies five new loci for coronary artery disease

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    Genome-wide association identifies nine common variants associated with fasting proinsulin levels and provides new insights into the pathophysiology of type 2 diabetes.

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    OBJECTIVE: Proinsulin is a precursor of mature insulin and C-peptide. Higher circulating proinsulin levels are associated with impaired β-cell function, raised glucose levels, insulin resistance, and type 2 diabetes (T2D). Studies of the insulin processing pathway could provide new insights about T2D pathophysiology. RESEARCH DESIGN AND METHODS: We have conducted a meta-analysis of genome-wide association tests of ∼2.5 million genotyped or imputed single nucleotide polymorphisms (SNPs) and fasting proinsulin levels in 10,701 nondiabetic adults of European ancestry, with follow-up of 23 loci in up to 16,378 individuals, using additive genetic models adjusted for age, sex, fasting insulin, and study-specific covariates. RESULTS: Nine SNPs at eight loci were associated with proinsulin levels (P < 5 × 10(-8)). Two loci (LARP6 and SGSM2) have not been previously related to metabolic traits, one (MADD) has been associated with fasting glucose, one (PCSK1) has been implicated in obesity, and four (TCF7L2, SLC30A8, VPS13C/C2CD4A/B, and ARAP1, formerly CENTD2) increase T2D risk. The proinsulin-raising allele of ARAP1 was associated with a lower fasting glucose (P = 1.7 × 10(-4)), improved β-cell function (P = 1.1 × 10(-5)), and lower risk of T2D (odds ratio 0.88; P = 7.8 × 10(-6)). Notably, PCSK1 encodes the protein prohormone convertase 1/3, the first enzyme in the insulin processing pathway. A genotype score composed of the nine proinsulin-raising alleles was not associated with coronary disease in two large case-control datasets. CONCLUSIONS: We have identified nine genetic variants associated with fasting proinsulin. Our findings illuminate the biology underlying glucose homeostasis and T2D development in humans and argue against a direct role of proinsulin in coronary artery disease pathogenesis

    Increasing frailty is associated with higher prevalence and reduced recognition of delirium in older hospitalised inpatients: results of a multi-centre study

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    Purpose: Delirium is a neuropsychiatric disorder delineated by an acute change in cognition, attention, and consciousness. It is common, particularly in older adults, but poorly recognised. Frailty is the accumulation of deficits conferring an increased risk of adverse outcomes. We set out to determine how severity of frailty, as measured using the CFS, affected delirium rates, and recognition in hospitalised older people in the United Kingdom. Methods: Adults over 65 years were included in an observational multi-centre audit across UK hospitals, two prospective rounds, and one retrospective note review. Clinical Frailty Scale (CFS), delirium status, and 30-day outcomes were recorded. Results: The overall prevalence of delirium was 16.3% (483). Patients with delirium were more frail than patients without delirium (median CFS 6 vs 4). The risk of delirium was greater with increasing frailty [OR 2.9 (1.8–4.6) in CFS 4 vs 1–3; OR 12.4 (6.2–24.5) in CFS 8 vs 1–3]. Higher CFS was associated with reduced recognition of delirium (OR of 0.7 (0.3–1.9) in CFS 4 compared to 0.2 (0.1–0.7) in CFS 8). These risks were both independent of age and dementia. Conclusion: We have demonstrated an incremental increase in risk of delirium with increasing frailty. This has important clinical implications, suggesting that frailty may provide a more nuanced measure of vulnerability to delirium and poor outcomes. However, the most frail patients are least likely to have their delirium diagnosed and there is a significant lack of research into the underlying pathophysiology of both of these common geriatric syndromes

    Needs, wants and goals: wellbeing, quality of life and public policy

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    This paper considers the possible contribution of Quality of Life methods in international development policy and practice. It discusses the role of theories of human needs in how public policy makers and implementors might distinguish between 'needs' and 'wants'. There is a good case for extending theories of human need to encompass social and psychological needs, but when we do so the ability of theory to distinguish between 'needs' and 'wants' begins to evaporate. Rather, by virtue of the core relationship between needs denial and harm, it is argued that a theory of human need can provide a framework for reasoning about what constitute needs. Empirical quality of life data can then assist policy makers to identify what constitute needs satisfiers in particular societal and cultural contexts. They also can provide important information to enable processes of public reasoning about the relative societal importance of different needs claims. The paper uses data generated through the application of two Quality of Life methods in Southern and Northeast Thailand, which were employed as part of a comprehensive study of the social and cultural construction of wellbeing in developing countries, to illustrate its arguments. The paper concludes that if routinely incorporated into local policy process, such quality of life methods have a possible contribution to make to effective democratic governance for development.</p
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