5,015 research outputs found
CONSUMER, WHOLESALER AND RETAILER PERCEPTIONS ABOUT SELECTED MARKETING ISSUES CONCERNING FRESH FISH AND SEAFOOD PRODUCTS
Consumer/Household Economics, Marketing,
A Hierarchical Multivariate Two-Part Model for Profiling Providers\u27 Effects on Healthcare Charges
Procedures for analyzing and comparing healthcare providers\u27 effects on health services delivery and outcomes have been referred to as provider profiling. In a typical profiling procedure, patient-level responses are measured for clusters of patients treated by providers that in turn, can be regarded as statistically exchangeable. Thus, a hierarchical model naturally represents the structure of the data. When provider effects on multiple responses are profiled, a multivariate model rather than a series of univariate models, can capture associations among responses at both the provider and patient levels. When responses are in the form of charges for healthcare services and sampled patients include non-users of services, charge variables are a mix of zeros and highly-skewed positive values that present a modeling challenge. For analysis of regressor effects on charges for a single service, a frequently used approach is a two-part model (Duan, Manning, Morris, and Newhouse 1983) that combines logistic or probit regression on any use of the service and linear regression on the log of positive charges given use of the service. Here, we extend the two-part model to the case of charges for multiple services, using a log-linear model and a general multivariate log-normal model, and employ the resultant multivariate two-part model as the within-provider component of a hierarchical model. The log-linear likelihood is reparameterized as proposed by Fitzmaurice and Laird (1993), so that regressor effects on any use of each service are marginal with respect to any use of other services. The general multivariate log-normal likelihood is constructed in such a way that variances of log of positive charges for each service are provider-specific but correlations between log of positive charges for different services are uniform across providers. A data augmentation step is included in the Gibbs sampler used to fit the hierarchical model, in order to accommodate the fact that values of log of positive charges are undefined for unused service. We apply this hierarchical, multivariate, two-part model to analyze the effects of primary care physicians on their patients\u27 annual charges for two services, primary care and specialty care. Along the way, we also demonstrate an approach for incorporating prior information about the effects of patient morbidity on response variables, to improve the accuracy of provider profiles that are based on patient samples of limited size
RNA-seq reveals post-transcriptional regulation of Drosophila insulin-like peptide dilp8 and the neuropeptide-like precursor Nplp2 by the exoribonuclease Pacman/XRN1
Ribonucleases are critically important in many cellular and developmental processes and defects in their expression are associated with human disease. Pacman/XRN1 is a highly conserved cytoplasmic exoribonuclease which degrades RNAs in a 5' - 3' direction. In Drosophila, null mutations in pacman result in small imaginal discs, a delay in onset of pupariation and lethality during the early pupal stage. In this paper, we have used RNA-seq in a genome-wide search for mRNAs misregulated in pacman null wing imaginal discs. Only 4.2% of genes are misregulated ±>2-fold in pacman null mutants compared to controls, in line with previous work showing that Pacman has specificity for particular mRNAs. Further analysis of the most upregulated mRNAs showed that Pacman post-transcriptionally regulates the expression of the secreted insulin-like peptide Dilp8. Dilp8 is related to human IGF-1, and has been shown to co-ordinate tissue growth with developmental timing in Drosophila. The increased expression of Dilp8 is consistent with the developmental delay seen in pacman null mutants. Our analysis, together with our previous results, show that the normal role of this exoribonuclease in imaginal discs is to suppress the expression of transcripts that are crucial in apoptosis and growth control during normal development
First Simultaneous Optical and EUV Observations of the Quasi-Coherent Oscillations of SS Cygni
Using EUV photometry obtained with the Extreme Ultraviolet Explorer (EUVE)
satellite and UBVR optical photometry obtained with the 2.7-m telescope at
McDonald Observatory, we have detected quasi-coherent oscillations (so-called
``dwarf nova oscillations'') in the EUV and optical flux of the dwarf nova SS
Cygni during its 1996 October outburst. There are two new results from these
observations. First, we have for the first time observed ``frequency
doubling:'' during the rising branch of the outburst, the period of the EUV
oscillation was observed to jump from 6.59 s to 2.91 s. Second, we have for the
first time observed quasi-coherent oscillations simultaneously in the optical
and EUV. We find that the period and phase of the oscillations are the same in
the two wavebands, finally confirming the long-held assumption that the periods
of the optical and EUV/soft X-ray oscillations of dwarf novae are equal. The
UBV oscillations can be simply the Rayleigh-Jeans tail of the EUV oscillations
if the boundary layer temperature kT_bb <~ 15 eV and hence the luminosity L_bb
>~ 1.2e34 (d/75 pc)^2 erg/s (comparable to that of the accretion disk).
Otherwise, the lack of a phase delay between the EUV and optical oscillations
requires that the optical reprocessing site lies within the inner third of the
accretion disk. This is strikingly different from other cataclysmic variables,
where much or all of the disk contributes to the optical oscillations.Comment: 16 pages including 3 tables and 4 encapsulated postscript figures;
LaTeX format, uses aastex.cls; accepted on 2001 August 2 for publication in
The Astrophysical Journa
Studying Effects of Primary Care Physicians and Patients on the Trade-Off Between Charges for Primary Care and Specialty Care Using a Hierarchical Multivariate Two-Part Model
Objective. To examine effects of primary care physicians (PCPs) and patients on the association between charges for primary care and specialty care in a point-of-service (POS) health plan.
Data Source. Claims from 1996 for 3,308 adult male POS plan members, each of whom was assigned to one of the 50 family practitioner-PCPs with the largest POS plan member-loads.
Study Design. A hierarchical multivariate two-part model was fitted using a Gibbs sampler to estimate PCPs\u27 effects on patients\u27 annual charges for two types of services, primary care and specialty care, the associations among PCPs\u27 effects, and within-patient associations between charges for the two services. Adjusted Clinical Groups (ACGs) were used to adjust for case-mix.
Principal Findings. PCPs with higher case-mix adjusted rates of specialist use were less likely to see their patients at least once during the year (estimated correlation: –.40; 95% CI: –.71, –.008) and provided fewer services to patients that they saw (estimated correlation: –.53; 95% CI: –.77, –.21). Ten of 11 PCPs whose case-mix adjusted effects on primary care charges were significantly less than or greater than zero (p \u3c .05) had estimated, case-mix adjusted effects on specialty care charges that were of opposite sign (but not significantly different than zero). After adjustment for ACG and PCP effects, the within-patient, estimated odds ratio for any use of primary care given any use of specialty care was .57 (95% CI: .45, .73).
Conclusions. PCPs and patients contributed independently to a trade-off between utilization of primary care and specialty care. The trade-off appeared to partially offset significant differences in the amount of care provided by PCPs. These findings were possible because we employed a hierarchical multivariate model rather than separate univariate models
The extinct, giant giraffid Sivatherium giganteum: skeletal reconstruction and body mass estimation
Sivatherium giganteum is an extinct giraffid from the Plio–Pleistocene boundary of the Himalayan foothills. To date, there has been no rigorous skeletal reconstruction of this unusual mammal. Historical and contemporary accounts anecdotally state that Sivatherium rivalled the African elephant in terms of its body mass, but this statement has never been tested. Here, we present a three-dimensional composite skeletal reconstruction and calculate a representative body mass estimate for this species using a volumetric method. We find that the estimated adult body mass of 1246 kg (857—1812 kg range) does not approach that of an African elephant, but confirms that Sivatherium was certainly a large giraffid, and may have been the largest ruminant mammal that has ever existed. We contrast this volumetric estimate with a bivariate scaling estimate derived from Sivatherium's humeral circumference and find that there is a discrepancy between the two. The difference implies that the humeral circumference of Sivatherium is greater than expected for an animal of this size, and we speculate this may be linked to a cranial shift in centre of mass
Internal dose escalation is associated with increased local control for non-small cell lung cancer (NSCLC) brain metastases treated with stereotactic radiosurgery (SRS)
Athletes' experiences of social support during their transition out of elite sport: An interpretive phenomenological analysis
Objectives
The sources and types of social support that athletes receive during the transition out of sport have been well documented. However, less is known about how athletes perceive, mobilise, and manage supportive relationships. This study aimed therefore to gain a more comprehensive insight into the ways that social support may influence how athletes adjust to life following retirement from elite sport.
Design
The study was designed according to the principles of Interpretative Phenomenological Analysis.
Method
Eight former British elite athletes (four male and four female) from eight different Olympic sports were recruited using criterion-based purposive sampling strategies. Data collected using semi-structured interviews were analysed to explore subjective experiences of social support during transition.
Results
Participants' perception of feeling cared for and understood enabled support to be effective. There were variations in participants' ability to seek out and ask for support and those who found this difficult also found transition a more distressing experience. As transitions progressed, the adjustment process was closely linked to the participant's evolving sense of self. New social relationships and social roles fostered a sense of feeling supported, as well as providing opportunities to support others (e.g., other retired athletes). Providing support helped the participants to experience a sense of growth that facilitated adjustment to life after sport.
Conclusions
The content of support was largely dependent on context; that is, perceptions of supporters were just as important, if not more so, than specific support exchanges. Stigma around asking for help was a barrier to support seeking
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