2,487 research outputs found
Structured count data regression
Overdispersion in count data regression is often caused by neglection or inappropriate modelling of individual heterogeneity, temporal or spatial correlation, and nonlinear covariate effects. In this paper, we develop and study semiparametric count data models which can deal with these issues by incorporating corresponding components in structured additive form into the predictor. The models are fully Bayesian and inference is carried out by computationally efficient MCMC techniques. In a simulation study, we investigate how well the different components can be identified with the data at hand. The approach is applied to a large data set of claim frequencies from car insurance
A novel R-package graphic user interface for the analysis of metabonomic profiles
Background Analysis of the plethora of metabolites found in the NMR spectra of biological fluids or tissues requires data complexity to be simplified. We present a graphical user interface (GUI) for NMR-based metabonomic analysis. The "Metabonomic Package" has been developed for metabonomics research as open-source software and uses the R statistical libraries. /Results The package offers the following options: Raw 1-dimensional spectra processing: phase, baseline correction and normalization. Importing processed spectra. Including/excluding spectral ranges, optional binning and bucketing, detection and alignment of peaks. Sorting of metabolites based on their ability to discriminate, metabolite selection, and outlier identification. Multivariate unsupervised analysis: principal components analysis (PCA). Multivariate supervised analysis: partial least squares (PLS), linear discriminant analysis (LDA), k-nearest neighbor classification. Neural networks. Visualization and overlapping of spectra. Plot values of the chemical shift position for different samples. Furthermore, the "Metabonomic" GUI includes a console to enable other kinds of analyses and to take advantage of all R statistical tools. /Conclusion We made complex multivariate analysis user-friendly for both experienced and novice users, which could help to expand the use of NMR-based metabonomics
Preinvex functions and weak efficient solutions for some vectorial optimization problem in Banach spaces
AbstractIn this work, we introduce the notion of preinvex function for functions between Banach spaces. By using these functions, we obtain necessary and sufficient conditions of optimality for vectorial problems with restrictions of inequalities. Moreover, we will show that this class of problems has the property that each local optimal solution is in fact global
Treatment of halogenated organic compounds and monitoring of microbial dynamics in up-flow fixed bed reactors under sequentially alternating pollutant scenarios
Two up-flow fixed bed reactors (UFBR) were
operated for 8 months treating a model synthetic wastewater containing 2-fluorobenzoate (2-FB) and dichloromethane
(DCM). The stability of the reactors under dynamic conditions, that is, sequentially alternating pollutants (SAP), shock loads, and starvation periods was assessed. Two
support materials were used: expanded clay (EC) that does not adsorb 2-FB or DCM, and granular-activated carbon (GAC) that adsorbs 180 mg gg⁻¹ of 2-FB and 390 mg gg⁻¹ of DCM. The reactors were inoculated with a 2-FB-degrading strain (FB2) and a DCM degrader (TM1). 2-FB was fed at organic loads ranging from 0 to 800 mg L⁻¹ d⁻¹, while DCM was fed at 0–250 mg L⁻¹ d⁻¹. 2-FB or DCM were never detected at the outlet of the GAC reactor, while in the EC reactor outlet small amounts were observed. Nevertheless, the highest biological elimination capacity was observed in
the EC reactor (over 700 mg L⁻¹ d⁻¹ of 2-FB). DGGE analysis revealed a fairly stable bacterial community with the largest shifts occurring during starvation periods and changes in feed composition. Several bacterial strains isolated from the reactors showed capacity for 2-FB degradation, while only strain TM1 degraded DCM
Biotreatment of industrial wastewaters under transient-state conditions: process stability with fluctuations of organic load, substrates, toxicants, and environmental parameters
Biotreatment of industrial wastewater is often challenged by operation under transient states with respect to organic loads, pollutants, and physical characteristics. Furthermore, the potential presence of inhibitory compounds requires careful monitoring and adequate process design. This review describes difficulties encountered in biological treatment of wastewater with highly variable influent characteristics. Typical design aspects of biological processes are presented and discussed with respect to their success in treating highly fluctuating wastewaters. In general, biomass retention is a key factor for dealing with highly fluctuating and/or inhibitory wastewater, but the how it operates also affects the stability of performance, as it was shown that dynamic operation instead of operation at a constant flow enhances biodegradation onset and more evenly distributed activity. Although ultimately stable effluent quality must be achieved, the microbial population stability is not necessarily high, as it was shown that microbial diversity and flexibility may play a critical role in functional stability.info:eu-repo/semantics/acceptedVersio
Isolation of a Xanthobacter sp. degrading dichloromethane and characterization of the gene involved in the degradation
A bacterial strain able to degrade dichloromethane (DCM) as the sole carbon source was isolated from a wastewater treatment plant receiving domestic and pharmaceutical effluent. 16S rDNA studies revealed the strain to be a Xanthobacter sp. (strain TM1). The new isolated strain when grown aerobically on DCM showed Luong type growth kinetics, with lmax of 0.094 h-1 and Sm of 1,435 mg l-1. Strain TM1 was able to degrade other aromatic and aliphatic halogenated compounds, such as halobenzoates, 2-chloroethanol and dichloroethane. The gene for DCM dehalogenase, which is the key enzyme in DCM degradation, was amplified through PCR reactions. Strain TM1 contains type A DCM dehalogenase (dcmAa), while no product could be obtained for type B dehalogense (dcmAb). The sequence was compared against 12 dcmAa from other DCM degrading strains and 98% or 99% similarity was observed with all other previously isolated DCM dehalogenase genes. This is the first time a Xanthobacter sp. is reported to degrade DCM.info:eu-repo/semantics/acceptedVersio
Nitrate regulates floral induction in Arabidopsis,acting independently of light, gibberellin and autonomous pathways.
Relación entre el color de epidermis y algunas características de calidad en frutos de aguacate 'Hass’.
Mexico is the main 'Hass' avocado exporter in the world. More than 300,0001 are exported every year. The United States of America, Japan, the European Union, and Canada are the main importer countries. Recently, 'Hass'avocado shipments to Canada containing fruit with skin blackening have been rejected since this characteristic is associated with low pulp firmness and short shelf life. The objective of this study was to determine the relationship between skin color of 'Hass' avocado fruit with quality characteristics. Fruit varying in black skin color (from 0 to 100%, categories 1 to 5) were collected from two different packinghouses in Michoacán, Mexico. Treatments were arranged in a split-plot design with five replications. Significant differences were detected between packinghouses for weight, length, skin color ('a', ‘b’, chroma and hue) and pulp firmness but not for width, dry matter content or the Avocado Maturity Index (AMI). As color skin category increased towards more blackened fruit, AMI value increased, firmness decreased but dry matter content did not change. These results provide evidence that fruit skin blackening is not associated with lower fruit quality, but it did lower pulp firmness at fruit packing.México es el principal exportador de aguacate 'Hass' en el mundo con más de 300,000 t anuales. Los principales importadores son Estados Unidos de América, Japón, la Unión Europea y Canadá. Recientemente, embarques de aguacate 'Hass' que contenían frutos con ennegrecimiento de la epidermis fueron rechazados por el mercado canadiense, ya que esta característica se asocia con baja firmeza de pulpa y corta vida de anaquel. El objetivo de este estudio fue determinar la relación entre el color de la epidermis de frutos de aguacate 'Hass' con algunas características de calidad. En dos empacadoras de Michoacán, México, se tomaron muestras de frutos con diferentes porcentajes de color negro en la epidermis (de 0 a 100%; categorías 1 a 5). A cada fruto se le midió el color externo [luminosidad (L), 'a', 'b', croma y ángulo de tono], firmeza de pulpa,contenido de materia seca y el índice de maduración. Se empleó un diseño de parcelas divididas con cinco repeticiones. Se detectaron diferencias significativas entre empacadoras para peso, largo, color de cascara ('a', b', croma y hue) así como para firmeza de pulpa pero no para ancho, contenido de materia seca ni el índice de maduración. Se observó que conforme el color de categoría se incrementó hacia frutos más obscuros, los valores del índice de madurez se incrementaron, la firmeza disminuyó pero el contenido de materia seca no varió. Estos resultados proveen evidencia de que el obscurecimiento de la cascara no está asociado con la baja calidad de los frutos, aunque sí con la disminución de la firmeza de pulpa al momento del empacado
Supporting the inclusion and retention of autistic students: Exploring teachers' and paraeducators' use of evidence-based practices in public elementary schools
Introduction: Educators in public schools are required to serve students in their least restrictive environment. While many evidence-based practices (EBPs), defined as practices and strategies shown by research to have meaningful effectson outcomes for autistic students are documented in the literature, less is known about EBP use among educators in public schools.
Methods: Eighty-six general and special education teachers and para educators completed a survey about familiarity, training, and EBP use for included autistic children.
Results: Across roles, educators reported familiarity (98.8%), use (97.7%), and training (83.7%) in reinforcement. They reported the least familiarity with behavioral momentum (29.1%), training in both video modeling and peer-mediated instruction and intervention (18.6%), and use of video modeling (14.0%). Follow-up interviews (n = 80) highlighted mixed understanding of EBP definitions and use.
Discussion: Implications for inclusive education are discussed including autism-specific EBP training within pre-service teacher preparation programs
Evaluation of grip strength in hook of hamate fractures treated with osteosynthesis. Is this surgical treatment necessary?
Objective: The aim of this study was to evaluate the outcomes of open reduction and internal fixation (ORIF) in hamate hook fractures and review the literature on this surgical procedure. Methods: We report the outcomes of ORIF of hamate hook fractures in 13 consecutive patients (12 men and 1 woman; mean age: 32 years (range, 22-48 years)). In eight patients (61%) the fracture was associated with ulnar nerve neuritis in Guyon's canal. We assessed the following clinical data: age, sex, mechanism of injury, side of the injured hand and associated lesions, fracture classification, average time from injury to correct diagnosis, surgical technique, complications, and length of follow-up. All patients underwent radiological imaging, including standard radiographs in two planes (anteroposterior and lateral projections), and a CT study. Functional outcomes evaluated were pain, range of motion, grip strength, Disabilities of the arm, shoulder and hand (DASH) and Mayo wrist score. Results: The mean follow-up was 36 months (range, 12-144 months). All 13 cases were treated with ORIF of the hook of the hamate. Mean VAS pain score was 5 preoperatively (4-9) and 1 (0-2) postoperatively. All patients returned to pre-injury level and only one patient felt pain on activity. Preoperative modified Mayo wrist score was 51 and the postoperative value was 94. All outcomes scores improved significantly from preoperative values. The patients who participated in sports postoperatively were able to do so at or near pre-injury levels. Postoperative average range of wrist motion was 76° in extension, 71° in flexion, 14° in ulnar deviation, and 21° in radial deviation. Mean grip strength in the hand with the hook fracture was 58 kg compared with 53 Kg in the unaffected hand. All patients returned to their pre-injury level of functioning after 10-12 weeks and there were no complications. Analysis of grip strength revealed values comparable with the unaffected hand. Conclusion: ORIF of hamate hook fractures is a safe and effective technique to restore normal grip strength and return to pre-injury level. In cases of ulnar nerve neuritis, neurolysis of the deep palmar branch is mandatory. Level of evidence: Level IV, Therapeutic study
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