29,100 research outputs found
Second order ancillary: A differential view from continuity
Second order approximate ancillaries have evolved as the primary ingredient
for recent likelihood development in statistical inference. This uses quantile
functions rather than the equivalent distribution functions, and the intrinsic
ancillary contour is given explicitly as the plug-in estimate of the vector
quantile function. The derivation uses a Taylor expansion of the full quantile
function, and the linear term gives a tangent to the observed ancillary
contour. For the scalar parameter case, there is a vector field that integrates
to give the ancillary contours, but for the vector case, there are multiple
vector fields and the Frobenius conditions for mutual consistency may not hold.
We demonstrate, however, that the conditions hold in a restricted way and that
this verifies the second order ancillary contours in moderate deviations. The
methodology can generate an appropriate exact ancillary when such exists or an
approximate ancillary for the numerical or Monte Carlo calculation of
-values and confidence quantiles. Examples are given, including nonlinear
regression and several enigmatic examples from the literature.Comment: Published in at http://dx.doi.org/10.3150/10-BEJ248 the Bernoulli
(http://isi.cbs.nl/bernoulli/) by the International Statistical
Institute/Bernoulli Society (http://isi.cbs.nl/BS/bshome.htm
Theoretical investigation - The scattering of light by a planetary atmosphere Interim report, 22 Sep. - 22 Dec. 1965
Light scattering and polarization in planetary atmospher
Mining electron density for functionally relevant protein polysterism in crystal structures.
This review focuses on conceptual and methodological advances in our understanding and characterization of the conformational heterogeneity of proteins. Focusing on X-ray crystallography, we describe how polysterism, the interconversion of pre-existing conformational substates, has traditionally been analyzed by comparing independent crystal structures or multiple chains within a single crystal asymmetric unit. In contrast, recent studies have focused on mining electron density maps to reveal previously 'hidden' minor conformational substates. Functional tests of the importance of minor states suggest that evolutionary selection shapes the entire conformational landscape, including uniquely configured conformational substates, the relative distribution of these substates, and the speed at which the protein can interconvert between them. An increased focus on polysterism may shape the way protein structure and function is studied in the coming years
High Heritability Is Compatible with the Broad Distribution of Set Point Viral Load in HIV Carriers.
Set point viral load in HIV patients ranges over several orders of magnitude and is a key determinant of disease progression in HIV. A number of recent studies have reported high heritability of set point viral load implying that viral genetic factors contribute substantially to the overall variation in viral load. The high heritability is surprising given the diversity of host factors associated with controlling viral infection. Here we develop an analytical model that describes the temporal changes of the distribution of set point viral load as a function of heritability. This model shows that high heritability is the most parsimonious explanation for the observed variance of set point viral load. Our results thus not only reinforce the credibility of previous estimates of heritability but also shed new light onto mechanisms of viral pathogenesis
An investigation, evaluation and development of techniques to enable the spread and adoption of innovative practices, based on the Trent region older people services project (TROPSP)
This report contributes just over a third of the contribution to the researcher's D.Prof programme (see Ai Exhibits). It is a synthesis of many different activities and avenues of investigation and learning. This report is about one specific project and is focused on the ways to support the spread and adoption of innovative practices. It is not intended to be a report of the entire D.Prof Programme as the other areas are covered separately (see Exhibits Ai for D.Prof Programme Design). The literature review threw up a number of conflicts of definitions and perspectives, especially in the terminology that can be applied to 'spreading good practice' and 'social marketing'. The many paradoxes and contested concepts are highlighted in the review and the discussion that follows. Whilst this part of the D.Prof programme is centred on a work-based project - The Trent Region Older People Services Programme (TROPSP) - it has been difficult to separate learning in this project from other work based experiences in the same period. The deliverables and outputs generated (see Part B Exhibits) demonstrate both the breadth and depth of the researcher's experience and learning during this D.Prof programme. The experiential nature of action-based research is highly subjective as the researcher is an active participant in the investigative process, where personal actions immediately affect and have consequences on the context and subject matter under investigation. This report, therefore, needs to be read in the light of its context for the researcher, and understood as a piece of qualitative, action orientated research, rather than an analysis driven by more positivist or scientific values. The literature review, assessment of the TROPSP project and discussion about the researcher's personal learning themes, combine to produce a set of conclusions and recommendation as diverse and contested as is the topic of interprofessional social marketing itself. The paradoxes and tensions include: how different theories and frameworks can form unhelpful (or helpful) mental models; the importance of context, perspectives and expectations and how they can influence strategy and implementation of good practice; the tension between the individual and the organisation; how working with key influencers can be as damaging as it can be as supportive; and finally, the issue of whether the aim in social marketing is to spread good practice (Push out) or to enable adoption (Pull in). The work summarised in this report has received national and international recognition. The contribution to the modernising the NBS has been significant and there is much interest from other countries in using some of the techniques developed and used in the TROPSP work based project. The implications for professional practice, for those working with modernising healthcare as well as specifically for the researcher, are important
Lack of an HSP70 heat shock response in two Antarctic marine invertebrates
Members of the HSP70 gene family comprising the inducible (HSP70) genes and GRP78 (glucose-regulated protein 78 kDa) were identified in an Antarctic sea star (Odontaster validus) and an Antarctic gammarid (Paraceradocus gibber). These genes were surveyed for expression levels via Q-PCR after an acute 2-hour heat shock experiment in both animals and a time course assay in O. validus. No significant up-regulation was detected for any of the genes in either of the animals during the acute heat shock. The time course experiment in O. validus produced slightly different results with an initial down regulation in these genes at 2°C, but no significant up-regulation of the genes either at 2 or 6°C. Therefore, the classical heat shock response is absent in both species. The data is discussed in the context of the organisms’ thermal tolerance and the applicability of HSP70 to monitor thermal stress in Antarctic marine organisms
Rates and predictors of recurrent work disability due to common mental health disorders in the United States.
ContextDespite the high prevalence of work disability due to common mental disorders (CMD), no information exists on the rates and predictors of recurrence in a United States population.ObjectiveTo estimate recurrent work disability statistics and evaluate factors associated with recurrence due to CMDs including adjustment, anxiety, bipolar, and depressive disorders.MethodsRecurrent work disability statistics were calculated using a nationwide database of disability claims. For the CMDs, univariate and multiple variable analyses were used to examine demographic factors and comorbidities associated with the time to recurrence.ResultsOf the CMDs, cases with bipolar (n = 3,017) and depressive disorders (n = 20,058) had the highest recurrence densities, 98.7 and 70.9 per 1000 person-years, respectively. These rates were more than three times higher than recurrence rates for other chronic disorders (e.g., diabetes, asthma; n = 105,558) and non-chronic disorders (e.g., injury, acute illnesses; n = 153,786). Individuals with CMD were also more likely to have a subsequent disability distinct from their mental health condition. Risk factors for recurrent CMD disability included being younger, being an hourly employee, living in a geographic area with more college graduates, having more previous psychiatric visits, having a previous work leave, and the type of work industry.ConclusionsResults indicate that CMD patients may benefit from additional care and disability management both during and after their work absence to help prevent subsequent CMD and non-CMD related leaves
The effect of surface reflection and clouds on the estimation of total ozone from satellite measurements
The total amount of ozone in a vertical column is being measured by Nimbus 4 and 7 observations of the intensity of ultraviolet sunlight scattered from the earth. The algorithm for deriving the amount of ozone from the observations uses the assumption that the surface reflects the light isotropically and the albedo is independent of wavelength. The effects of anisotropic surfaces and clouds on the estimate of total ozone are computed for models of the earth-atmosphere system
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