A Poisson Mixed Model with Nonnormal Random Effect Distribution

We propose in this paper a random intercept Poisson model in which the random effect distribution is assumed to follow a generalized log-gamma (GLG) distribution. We derive the first two moments for the marginal distribution as well as the intraclass correlation. Even though numerical integration methods are in general required for deriving the marginal models, we obtain the multivariate negative binomial model for a particular parameter setting of the hierarchical model. An iterative process is derived for obtaining the maximum likelihood estimates for the parameters in the multivariate negative binomial model. Residual analysis are proposed and two applications with real data are given for illustration.Comment: Submitted in the Computational Statistics & Data Analysis journa

The Privatization and Project Finance Adventure: Acquiring a Colombian Public Utility Company

Colombia is an exciting new arena for the international practitioner structuring project finance and privatization transactions. The sectors of the economy that are attractive targets for most multinationals (MNCs) entering Colombia are the energy, oil and gas, mining, water, and telecommunications sectors. In most cases, MNCs in these sectors consider investments in Colombia when the Colombian authorities announce a plan for the privatization or capitalization of state-run companies that have a monopoly on business. Often the MNC becomes aware of the privatization, concession, or capitalization project via an official announcement by the Colombian government calling for bids or an invitation informing the MNC that it is qualified for the particular project or a specific aspect of the project. When a client is interested in participating in the bid process, it will most certainly, unless it has participated in other bids in Colombia, approach counsel and its other advisors with assumptions of how the bid should be structured, from both a Colombian and U.S. angle. In these instances, the only option for counsel and other advisors is to listen and take note. The following key questions must be considered under this scenario: what type of restrictions exist under current privatization laws; what form of business association should be used; what is the tax treatment regarding business associations, dividend treatment, technical services and assistance contracts, and repatriation of profits; do foreign exchange regulations hinder the availability of using inter-company loans and foreign currency operations; how should the due diligence review be performed; and how should local counsel be chosen

The Privatization and Project Finance Adventure: Acquiring a Colombian Public Utility Company

Colombia is an exciting new arena for the international practitioner structuring project finance and privatization transactions. The sectors of the economy that are attractive targets for most multinationals (MNCs) entering Colombia are the energy, oil and gas, mining, water, and telecommunications sectors. In most cases, MNCs in these sectors consider investments in Colombia when the Colombian authorities announce a plan for the privatization or capitalization of state-run companies that have a monopoly on business. Often the MNC becomes aware of the privatization, concession, or capitalization project via an official announcement by the Colombian government calling for bids or an invitation informing the MNC that it is qualified for the particular project or a specific aspect of the project. When a client is interested in participating in the bid process, it will most certainly, unless it has participated in other bids in Colombia, approach counsel and its other advisors with assumptions of how the bid should be structured, from both a Colombian and U.S. angle. In these instances, the only option for counsel and other advisors is to listen and take note. The following key questions must be considered under this scenario: what type of restrictions exist under current privatization laws; what form of business association should be used; what is the tax treatment regarding business associations, dividend treatment, technical services and assistance contracts, and repatriation of profits; do foreign exchange regulations hinder the availability of using inter-company loans and foreign currency operations; how should the due diligence review be performed; and how should local counsel be chosen

2b-RAD genotyping for population genomic studies of Chagas disease vectors: Rhodnius ecuadoriensis in Ecuador

Background: Rhodnius ecuadoriensis is the main triatomine vector of Chagas disease, American trypanosomiasis, in Southern Ecuador and Northern Peru. Genomic approaches and next generation sequencing technologies have become powerful tools for investigating population diversity and structure which is a key consideration for vector control. Here we assess the effectiveness of three different 2b restriction site-associated DNA (2b-RAD) genotyping strategies in R. ecuadoriensis to provide sufficient genomic resolution to tease apart microevolutionary processes and undertake some pilot population genomic analyses. Methodology/Principal findings: The 2b-RAD protocol was carried out in-house at a non-specialized laboratory using 20 R. ecuadoriensis adults collected from the central coast and southern Andean region of Ecuador, from June 2006 to July 2013. 2b-RAD sequencing data was performed on an Illumina MiSeq instrument and analyzed with the STACKS de novo pipeline for loci assembly and Single Nucleotide Polymorphism (SNP) discovery. Preliminary population genomic analyses (global AMOVA and Bayesian clustering) were implemented. Our results showed that the 2b-RAD genotyping protocol is effective for R. ecuadoriensis and likely for other triatomine species. However, only BcgI and CspCI restriction enzymes provided a number of markers suitable for population genomic analysis at the read depth we generated. Our preliminary genomic analyses detected a signal of genetic structuring across the study area. Conclusions/Significance: Our findings suggest that 2b-RAD genotyping is both a cost effective and methodologically simple approach for generating high resolution genomic data for Chagas disease vectors with the power to distinguish between different vector populations at epidemiologically relevant scales. As such, 2b-RAD represents a powerful tool in the hands of medical entomologists with limited access to specialized molecular biological equipment. Author summary: Understanding Chagas disease vector (triatomine) population dispersal is key for the design of control measures tailored for the epidemiological situation of a particular region. In Ecuador, Rhodnius ecuadoriensis is a cause of concern for Chagas disease transmission, since it is widely distributed from the central coast to southern Ecuador. Here, a genome-wide sequencing (2b-RAD) approach was performed in 20 specimens from four communities from Manabí (central coast) and Loja (southern) provinces of Ecuador, and the effectiveness of three type IIB restriction enzymes was assessed. The findings of this study show that this genotyping methodology is cost effective in R. ecuadoriensis and likely in other triatomine species. In addition, preliminary population genomic analysis results detected a signal of population structure among geographically distinct communities and genetic variability within communities. As such, 2b-RAD shows significant promise as a relatively low-tech solution for determination of vector population genomics, dynamics, and spread

Effect of molecular weight reduction by gamma irradiation on the antioxidant capacity of chitosan from lobster shells

AbstractThis study assessed the effect of molecular weight (MW) reduction by gamma irradiation on the antioxidant capacity of chitosan with potential application in the preservation of foodstuffs. Two batches of chitosan were obtained by heterogeneous chemical N-deacetylation of chitin from common lobster (Panulirus argus). Irradiation of chitosan was performed using a 60Co source and applying doses of 5, 10, 20 and 50 kGy with a dose rate of 10 kGy/h. Attenuated Total Reflection Fourier Transform Infrared Spectroscopy was used to identify main chemical features of chitosan. The average viscosimetric MW was determined by the viscosimetric method while the deacetylation degree by a potentiometric method. Thermogravimetric analysis and differential scanning calorimetry were conducted to evaluate the thermal degradation behavior of the chitosan samples, both under nitrogen flow. The antioxidant activity of chitosan solutions at 1% (w/v) in lactic acid at 1% (v/v) and Tween 80 at 0.1% (v/v) was evaluated through the ABTS assay and scavenging of DPPH radical by chitosan. The increase of irradiation dose with 60Co until 50 kGy decreased significantly the MW of chitosan through the scission of glycosidic bonds without affecting its functional groups, while the DD (72–75 %) did not vary (p > 0.05). The AC of the chitosan solutions increased with the reduction of MW of chitosan by gamma irradiation

Two-Centered Magical Charge Orbits

We determine the two-centered generic charge orbits of magical N = 2 and maximal N = 8 supergravity theories in four dimensions. These orbits are classified by seven U-duality invariant polynomials, which group together into four invariants under the horizontal symmetry group SL(2,R). These latter are expected to disentangle different physical properties of the two-centered black-hole system. The invariant with the lowest degree in charges is the symplectic product (Q1,Q2), known to control the mutual non-locality of the two centers.Comment: 1+17 pages, 1 Table; v2: Eq. (3.23) corrected; v3: various refinements in text and formulae, caption of Table 1 expanded, Footnote and Refs. added. To appear on JHE

We are more than EFL teachers-we are Educators: Emancipating EFL student-teachers through photovoice

The prevailing pedagogical orientations of English as a foreign language (EFL) education in Spain oppress learners intellectually in ways that are counterproductive to their learning. As a reaction to this, 129 EFL student-teachers (STs) took part during the 2013/14, 2014/15, and 2015/16 academic years in a workshop which drew on the methodology of participatory action research and on photovoice as a data-creating strategy, in order to emancipate these STs intellectually, boost their EFL development, and offer an alternative critical model for their future EFL teaching. The research was assessed collectively through a variety of qualitative strategies. Results showed that the photovoice workshop created a rich and meaningful context for EFL learning, one which enabled the STs to fully actualize their intellectual potential by producing knowledge collectively, thereby setting a memorable educational example for their own future teaching

Diagnostic Accuracy of Anthropometric Markers of Obesity for Prediabetes: A Systematic Review and Meta-Analysis

Introduction: Prediabetes is a significant public health concern due to its high risk of progressing to diabetes. Anthropometric measures of obesity, including body mass index (BMI), waist circumference (WC), and waist-to-height ratio (WHtR) have been demonstrated as key risk factors in the development of prediabetes. However, there is a lack of clarity on the diagnostic accuracy and cut-off points of these measures. Objective: To determine the diagnostic accuracy of these anthropometric measures for their most effective use in identifying prediabetes. Methodology: A systematic review (SR) with metanalysis of observational studies was carried out. The search was conducted in four databases: Pubmed/Medline, SCOPUS, Web of Science, and EMBASE. For the meta-analysis, sensitivity and specificity, together with their 95% confidence intervals (CI 95%) were calculated. Results: Among all the manuscripts chosen for review, we had four cross-sectional studies, and three were classified as cohort studies. The forest plots showed the combined sensitivity and specificity for both cross-sectional and cohort studies. For cross-sectional studies, the values were as follows: BMI had a sensitivity of 0.63 and specificity of 0.56, WC had a sensitivity of 0.59 and specificity of 0.58, and WHtR had a sensitivity of 0.63 and specificity of 0.73. In the cohort studies, the combined sensitivity and specificity were: BMI at 0.70 and 0.45, WC at 0.68 and 0.56, and WHtR at 0.68 and 0.56, respectively. All values are provided with 95% confidence intervals. Conclusions: This systematic review and meta-analysis evaluated the diagnostic accuracy of BMI, WC, and WHtR in identifying prediabetes. The results showed variations in sensitivity and specificity, with WHtR having the highest specificity in cross-sectional studies and BMI having improved sensitivity in cohort studies

Metabolically Obese Normal-Weight Phenotype as a Risk Factor for High Blood Pressure: A Five-Year Cohort

"Background: The metabolically obese normal-weight (MONW) phenotype has been considered a risk factor for different chronic diseases, but its role in high blood pressure (HBP) is still unclear. The aim of the study is to determine if the MONW phenotype constitutes a risk factor for hypertension in Peruvian adults belonging to a 5-year cohort. Methods: This is a retrospective cohort study. A secondary analysis from the database of the PERU MIGRANT study was carried out from the MONW and non-MONW cohorts; after a 5-year follow-up, the appearance of HBP was evaluated in the subjects of both cohorts. To assess the strength and magnitude of the association, a Poisson regression model (crude and adjusted) with robust variance was used. The measure of association was the relative risk (RR). Results: The incidence of HBP was 11.30%. In the multivariable analysis, subjects with the MONW phenotype had a 2.879-fold risk of presenting HBP in 5 years compared with those who were not MONW at the beginning of the study; this was adjusted for categorized age, sex, group, and state of smoker and alcohol drinker (RR: 2.055; 95% confidence interval (CI): 1.118 - 3.777; P = 0.020). Conclusions: The presence of the MONW phenotype doubled the incidence of HBP, even after adjusting for other covariates. However, studies in this field should continue. If these findings are confirmed, it should be considered that presenting an adequate weight for height should not be interpreted as a condition free of metabolic alterations, so screening for hypertension should be carried out regardless of w