A new method for the estimation of variance matrix with prescribed zeros in nonlinear mixed effects models

We propose a new method for the Maximum Likelihood Estimator (MLE) of nonlinear mixed effects models when the variance matrix of Gaussian random effects has a prescribed pattern of zeros (PPZ). The method consists in coupling the recently developed Iterative Conditional Fitting (ICF) algorithm with the Expectation Maximization (EM) algorithm. It provides positive definite estimates for any sample size, and does not rely on any structural assumption on the PPZ. It can be easily adapted to many versions of EM.Comment: Accepted for publication in Statistics and Computin

Cryptosporidium Spp. And Giardia Spp. In Feces And Water And The Associated Exposure Factors On Dairy Farms

The aims of this study were to verify the prevalence of Cryptosporidium spp. and Giardia spp. in animal feces and drinking water on dairy farms and to identify a possible relation between the exposure factors and the presence of these parasites. Fecal samples from cattle and humans and water samples were collected on dairy farms in Paraná, Brazil. Analysis of (oo)cysts in the feces was performed by the modified Ziehl-Neelsen staining and centrifugal flotation in zinc sulfate. Test-positive samples were subjected to nested PCR amplification of the 18SSU ribosomal RNA gene for identification of Cryptosporidium and Giardia and of the gp60 gene for subtyping of Cryptosporidium. Microbiological analysis of water was carried out by the multiple-tube method and by means of a chromogenic substrate, and parasitological analysis was performed on 31 samples by direct immunofluorescence and nested PCR of the genes mentioned above. Identification of the species of Cryptosporidium was performed by sequencing and PCR with analysis of restriction fragment length polymorphisms. The prevalence of Giardia and Cryptosporidium was higher in calves than in adults. Among the samples of cattle feces, Cryptosporidium parvum was identified in 41 (64%), C. ryanae in eight (12.5%), C. bovis in four (6.3%), C. andersoni in five (7.8%), and a mixed infection in 20 samples (31.3%). These parasites were not identified in the samples of human feces. Thermotolerant coliform bacteria were identified in 25 samples of water (45.5%). Giardia duodenalis and C. parvum were identified in three water samples. The gp60 gene analysis of C. parvum isolates revealed the presence of two strains (IIaA20G1R1 and IIaA17G2R2) in the fecal samples and one (IIaA17G2R1) in the water samples. The presence of coliforms was associated with the water source, structure and degradation of springs, rain, and turbidity. The prevalence of protozoa was higher in calves up to six months of age. C. parvum and G. duodenalis were identified in the water of dairy farms, as were thermotolerant coliforms; these findings point to the need for guidance on handling of animals, preservation of water sources, and water treatment. © 2017 Toledo et al.This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.12

Financial impact of breast cancer in black versus white women

Purpose Racial variation in the financial impact of cancer may contribute to observed differences in the use of guideline-recommended treatments. We describe racial differences with regard to the financial impact of breast cancer in a large population-based prospective cohort study. Methods The Carolina Breast Cancer Study oversampled black women and women younger than age 50 years with incident breast cancer in North Carolina from 2008 to 2013. Participants provided medical records and data regarding demographics, socioeconomic status, and financial impact of cancer at 5 and 25 months postdiagnosis. We report unadjusted and adjusted financial impact at 25 months postdiagnosis by race. Results The sample included 2,494 women who completed follow-up surveys (49% black, 51% white). Since diagnosis, 58% of black women reported any adverse financial impact of cancer (v 39% of white women; P, .001). In models adjusted for age, stage at diagnosis, and treatment received, black women were more likely to report adverse financial impact attributable to cancer (adjusted risk difference [aRD], +14 percentage points; P, .001), including income loss (aRD, +10 percentage points; P, .001), health care–related financial barriers (aRD, +10 percentage points; P, .001), health care–related transportation barriers (aRD, +10 percentage points; P, .001), job loss (aRD, 6 percentage points; P, .001), and loss of health insurance (aRD, +3 percentage points; P, .001). The effect of race was attenuated when socioeconomic factors were included but remained significant for job loss, transportation barriers, income loss, and overall financial impact. Conclusion Compared with white women, black women with breast cancer experience a significantly worse financial impact. Disproportionate financial strain may contribute to higher stress, lower treatment compliance, and worse outcomes by race. Policies that help to limit the effect of cancer-related financial strain are needed

Deep Submarine Giant Scours in northern Gulf of Cadiz (offshore SW Iberia): a singular case of sedimentary and tectonic coupling?

Multi-beam swath bathymetry carried out in NW Gulf of Cadiz(offshore SW Iberia - MATESPRO campaign) revealed several intriguing morphologic features, lying at depths between -3900 and - 4700 m., in an area characterized by very shallow general slope gradients (dipping approximately 0.4 degrees). These three dimensional features are characterized by elliptical crescent shapes of kilometric length (major axis around 5 km), displaying internal escarpments up to 100 m high and slopes varying between 6 and 14 degrees.A single channel seismic profile acquired across two of these features shows that they have a sub-surface composite structure. The internal part of the crescent consists of a depression filled up with upslope prograding sedimentary units developing towards the scarp that sharply truncates the sedimentary horizons. The growth processes of these structures appears to be by retrogressive displacement of a morphological scarp and remobilization followed by deposition of the eroded material in front of the scarp, prograding towards it. This process is similar to the development of contourite bodies in which the current direction is parallel to the scarp, whilst in the present case the flow direction may be mainly perpendicular to the scarp.These units are overlain by a sub-horizontal turbidite-like sedimentary unit that partially infills the depression. A deep multi-channel seismic profile across the same structure revealed the existence of an underlying thrust, part of a major structure, the Gulf of Cadiz Accretionary Prism. These singular features are interpreted as the coupled of sedimentary and tectonic processes. It is proposed that the Deep Submarine Giant Scours formed when a local morphologic irregularity, corresponding to the bathymetric expression of movement on an underlying thrust, is enhanced by the erosional activity of turbidity and thermohaline bottom currents driven by the formation of local eddies in front of the scarp. The drift results from the re-deposition of the eroded material in the same location

Predictors of Poor Neurocognitive Performance and Neuropsychological Phenotypes in Adolescents and Young Adults With Congenital Heart Disease

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