Prandtl-Batchelor theorem for three-dimensional flows slowly varying in one direction and its application to vortex breakdown

In this work, the Prandtl-Batchelor theorem is extended to three-dimensional flows slowly varying in one direction by using asymptotic techniques, and thus overcoming the problem of having non-closed streamlines for recirculating three-dimensional flows. The derived equations turned out to be an analogue of the quasi-cylindrical equations used for describing behavior of streamwise vortices, rotating jets, vortex breakdown phenomenon and some other problems. Hence, the derived equations may be used for studying similar phenomena in non-axisymmetric cases. In order to apply such a system of equations to particular problems, a computational code was developed and validated by reproducing numerical results available in the literature. This code was constructed in two parts, one part considered the parabolic system of partial differential equations as decoupled from the Poisson equation and the second part solved the nonlinear Poisson equation by using an iterative method. Finally, these two algorithms were joined in order to solve the entire system. Once the code was available, it was used to investigate possible non-axisymmetric effects on the position of vortex breakdown phenomenon. The results of this study suggest that non-axisymmetric effects precipitate the onset of vortex breakdown. From all this work, two articles were written, one article was published in the Journal of Fluid Mechanics (see Appendix D) and the second article will be submitted

Indicadores de sustentabilidad de un sistema agroforestal para el uso racional del agua del humedal La Segua, cantón Chone, Ecuador

El esquema se ajusta específicamente para la zona del Humedal la Segua, ubicada en el Cantón Chone de la Provincia de Manabí, el objetivo de este trabajo es el de generar un instrumento preliminar para de evaluar la incidencia de un Sistema Agroforestal (SAF) como alternativa para el uso eficiente del agua. La metodología de estudio se fundamenta en los principios de la agroecología y se diseña a partir de la integración de métodos de diagnóstico y evaluación utilizados por Santiago Sarandón para lograr el objetivo propuesto. Se propone elaborar los indicadores social, económico y ambiental para la evaluación de los sistemas, así como también proponer una planificación agroforestal para la protección de los cuerpos de agua del humedal. En este contexto, se contribuye a la eficiencia del uso adecuado del agua para las actividades agropecuarias y ecoturísticas; actividades que pueden ocasionar un gran desbalance en la agrobiodiversidad del ecosistema a estudiar

Cave macroinvertebrates used as bioindicators of water quality

Galindo-Pérez, E. J., Chávez-Sandoval, B. E., Espinoza- Graciano, E., Flores-Martínez, M. C., Villeda-Callejas, M. P., Bhalli, J. A., Tejocote-Pérez, M., & García-Franco, F. (September-October, 2017). Cave macroinvertebrates as bioindicators of water quality. Water Technology and Sciences (in Spanish), 8(5), 5-17. Caves are very fragile systems which are influenced by specific biogeographic and ecological patterns that maintain unique species of fauna, flora, and microbiota. One cave species, macroinvertebrates, represents a heterogeneous group of animal taxa which is in constant danger of extinction, principally due to anthropogenic activities. Macroinvertebrates have been widely used as bioindicators of the quality of biogeographic zones, ecosystems, and protected areas, as well as to determine protected species. The Boca del Río Cave is located in the biogeographic transition zone in Mexico’s Neotropical region, and is home to a large enclave of different biotic elements. Twenty-nine organisms were collected and grouped into 19 families based on their morphological and physiological characteristics. The coefficient of taxonomic work (CTW) indicates that the taxonomic level family is the most consistent for all of the organisms collected. The Coenagronidae family was the most abundant in the study. The BMWP, ASPT, and SCI biotic index scores indicate that the water in the Boca del Río Cave is slightly contaminated, while the Family Biotic Index (FBI) indicates poor water quality with very substantial organic pollution. The diversity of macroinvertebrate families confirms that the Boca del Río Cave serves as an important refuge for fauna in the transition zone located in Mexico’s Nearctic biogeographic region. This report represents the first study to use bioindicators to analyze the water quality of a cave system, and contributes to the inventories of macroinvertebrate cave fauna

Antimicrobial resistance among migrants in Europe: a systematic review and meta-analysis

BACKGROUND: Rates of antimicrobial resistance (AMR) are rising globally and there is concern that increased migration is contributing to the burden of antibiotic resistance in Europe. However, the effect of migration on the burden of AMR in Europe has not yet been comprehensively examined. Therefore, we did a systematic review and meta-analysis to identify and synthesise data for AMR carriage or infection in migrants to Europe to examine differences in patterns of AMR across migrant groups and in different settings. METHODS: For this systematic review and meta-analysis, we searched MEDLINE, Embase, PubMed, and Scopus with no language restrictions from Jan 1, 2000, to Jan 18, 2017, for primary data from observational studies reporting antibacterial resistance in common bacterial pathogens among migrants to 21 European Union-15 and European Economic Area countries. To be eligible for inclusion, studies had to report data on carriage or infection with laboratory-confirmed antibiotic-resistant organisms in migrant populations. We extracted data from eligible studies and assessed quality using piloted, standardised forms. We did not examine drug resistance in tuberculosis and excluded articles solely reporting on this parameter. We also excluded articles in which migrant status was determined by ethnicity, country of birth of participants' parents, or was not defined, and articles in which data were not disaggregated by migrant status. Outcomes were carriage of or infection with antibiotic-resistant organisms. We used random-effects models to calculate the pooled prevalence of each outcome. The study protocol is registered with PROSPERO, number CRD42016043681. FINDINGS: We identified 2274 articles, of which 23 observational studies reporting on antibiotic resistance in 2319 migrants were included. The pooled prevalence of any AMR carriage or AMR infection in migrants was 25·4% (95% CI 19·1-31·8; I2 =98%), including meticillin-resistant Staphylococcus aureus (7·8%, 4·8-10·7; I2 =92%) and antibiotic-resistant Gram-negative bacteria (27·2%, 17·6-36·8; I2 =94%). The pooled prevalence of any AMR carriage or infection was higher in refugees and asylum seekers (33·0%, 18·3-47·6; I2 =98%) than in other migrant groups (6·6%, 1·8-11·3; I2 =92%). The pooled prevalence of antibiotic-resistant organisms was slightly higher in high-migrant community settings (33·1%, 11·1-55·1; I2 =96%) than in migrants in hospitals (24·3%, 16·1-32·6; I2 =98%). We did not find evidence of high rates of transmission of AMR from migrant to host populations. INTERPRETATION: Migrants are exposed to conditions favouring the emergence of drug resistance during transit and in host countries in Europe. Increased antibiotic resistance among refugees and asylum seekers and in high-migrant community settings (such as refugee camps and detention facilities) highlights the need for improved living conditions, access to health care, and initiatives to facilitate detection of and appropriate high-quality treatment for antibiotic-resistant infections during transit and in host countries. Protocols for the prevention and control of infection and for antibiotic surveillance need to be integrated in all aspects of health care, which should be accessible for all migrant groups, and should target determinants of AMR before, during, and after migration. FUNDING: UK National Institute for Health Research Imperial Biomedical Research Centre, Imperial College Healthcare Charity, the Wellcome Trust, and UK National Institute for Health Research Health Protection Research Unit in Healthcare-associated Infections and Antimictobial Resistance at Imperial College London

Surgical site infection after gastrointestinal surgery in high-income, middle-income, and low-income countries: a prospective, international, multicentre cohort study

Background: Surgical site infection (SSI) is one of the most common infections associated with health care, but its importance as a global health priority is not fully understood. We quantified the burden of SSI after gastrointestinal surgery in countries in all parts of the world. Methods: This international, prospective, multicentre cohort study included consecutive patients undergoing elective or emergency gastrointestinal resection within 2-week time periods at any health-care facility in any country. Countries with participating centres were stratified into high-income, middle-income, and low-income groups according to the UN's Human Development Index (HDI). Data variables from the GlobalSurg 1 study and other studies that have been found to affect the likelihood of SSI were entered into risk adjustment models. The primary outcome measure was the 30-day SSI incidence (defined by US Centers for Disease Control and Prevention criteria for superficial and deep incisional SSI). Relationships with explanatory variables were examined using Bayesian multilevel logistic regression models. This trial is registered with ClinicalTrials.gov, number NCT02662231. Findings: Between Jan 4, 2016, and July 31, 2016, 13 265 records were submitted for analysis. 12 539 patients from 343 hospitals in 66 countries were included. 7339 (58·5%) patient were from high-HDI countries (193 hospitals in 30 countries), 3918 (31·2%) patients were from middle-HDI countries (82 hospitals in 18 countries), and 1282 (10·2%) patients were from low-HDI countries (68 hospitals in 18 countries). In total, 1538 (12·3%) patients had SSI within 30 days of surgery. The incidence of SSI varied between countries with high (691 [9·4%] of 7339 patients), middle (549 [14·0%] of 3918 patients), and low (298 [23·2%] of 1282) HDI (p < 0·001). The highest SSI incidence in each HDI group was after dirty surgery (102 [17·8%] of 574 patients in high-HDI countries; 74 [31·4%] of 236 patients in middle-HDI countries; 72 [39·8%] of 181 patients in low-HDI countries). Following risk factor adjustment, patients in low-HDI countries were at greatest risk of SSI (adjusted odds ratio 1·60, 95% credible interval 1·05–2·37; p=0·030). 132 (21·6%) of 610 patients with an SSI and a microbiology culture result had an infection that was resistant to the prophylactic antibiotic used. Resistant infections were detected in 49 (16·6%) of 295 patients in high-HDI countries, in 37 (19·8%) of 187 patients in middle-HDI countries, and in 46 (35·9%) of 128 patients in low-HDI countries (p < 0·001). Interpretation: Countries with a low HDI carry a disproportionately greater burden of SSI than countries with a middle or high HDI and might have higher rates of antibiotic resistance. In view of WHO recommendations on SSI prevention that highlight the absence of high-quality interventional research, urgent, pragmatic, randomised trials based in LMICs are needed to assess measures aiming to reduce this preventable complication

Production of He-4 and (4) in Pb-Pb collisions at root(NN)-N-S=2.76 TeV at the LHC

Results on the production of He-4 and (4) nuclei in Pb-Pb collisions at root(NN)-N-S = 2.76 TeV in the rapidity range vertical bar y vertical bar <1, using the ALICE detector, are presented in this paper. The rapidity densities corresponding to 0-10% central events are found to be dN/dy4(He) = (0.8 +/- 0.4 (stat) +/- 0.3 (syst)) x 10(-6) and dN/dy4 = (1.1 +/- 0.4 (stat) +/- 0.2 (syst)) x 10(-6), respectively. This is in agreement with the statistical thermal model expectation assuming the same chemical freeze-out temperature (T-chem = 156 MeV) as for light hadrons. The measured ratio of (4)/He-4 is 1.4 +/- 0.8 (stat) +/- 0.5 (syst). (C) 2018 Published by Elsevier B.V.Peer reviewe

Indicadores de sustentabilidad de un sistema agroforestal para el uso racional del agua del humedal La Segua, Cantón Chone, Ecuador

The scheme is specifically adjusted for the La Segua Wetland area, located in the Chone Canton of the Province of Manabí, the objective of this work is to generate a preliminary instrument to assess the incidence of the Agroforestry System (SAF) as an alternative for the efficient use of water. The study methodology is based on the principles of agroecology and is designed based on the integration of diagnostic and evaluation methods used by Santiago Sarandón to achieve the proposed objective. It is proposed to develop the social, economic and environmental indicators for the evaluation of the systems, as well as to propose agroforestry planning for the protection of wetland water bodies. In this context, it contributes to the efficiency of adequate water use for agricultural and ecotourism activities; activities that can cause a great imbalance in the agrobiodiversity of the ecosystem to studyEl esquema se ajusta específicamente para la zona del Humedal la Segua, ubicada en el Cantón Chone de la Provincia de Manabí, el objetivo de este trabajo es el de generar un instrumento preliminar para de evaluar la incidencia de un Sistema Agroforestal (SAF) como alternativa para el uso eficiente del agua. La metodología de estudio se fundamenta en los principios de la agroecología y se diseña a partir de la integración de métodos de diagnóstico y evaluación utilizados por Santiago Sarandón para lograr el objetivo propuesto. Se propone elaborar los indicadores social, económico y ambiental para la evaluación de los sistemas, así como también proponer una planificación agroforestal para la protección de los cuerpos de agua del humedal. En este contexto, se contribuye a la eficiencia del uso adecuado del aguapara las actividades agropecuarias y ecoturísticas; actividades que pueden ocasionar un gran desbalance en la agrobiodiversidad del ecosistema a estudiar

Mercury levels in muscle tissue of four common elasmobranch species from the Pacific coast of Costa Rica, Central America

Mercury (Hg) is a non-essential and toxic element that is ubiquitous in the marine environment and biomagnifies through food webs. Given the high trophic position of many elasmobranch species, it is important to quantify potentially harmful trace elements like Hg in their tissues, as this is an indicator of the level of contamination in the ecosystem. This study provides the first examination of total mercury (THg) concentrations in muscle tissue of four common demersal elasmobranchs (Mustelus henlei, Raja velezi, Torpedo peruana and Zapteryx xyster) from the Pacific coast of Costa Rica. All four species showed a positive relationship between THg concentration and body size, but THg concentration did not vary with trophic position. Torpedo peruana showed the highest THg concentration (mean ± SD: 0.52 ± 0.25 mg/kg wet weight) but Z. xyster had the highest slope for the THg-size relationship. The THg concentrations found in this study were lower than those reported for similar elasmobranch species in other regions, and only one sample exceeded the concentration limit suggested for human consumption. Our results suggest that THg contamination off the Pacific coast of Costa Rica, and possibly Central America is minimal.Consejo Nacional de Ciencia y Tecnología de Costa Rica/[FI-449-2010]/CONICIT/Costa RicaUniversidad de Costa Rica/[N°808-B0-536]/UCR/Costa RicaUniversidad de Costa Rica/[N°808-B1-547]/UCR/Costa RicaUniversidad de Costa Rica/[N°808-B1-537]/UCR/Costa RicaUniversidad de Costa Rica/[N°111-A4-508]/UCR/Costa RicaUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR

Tratamiento del Pectus excavatum con cirugía minimamente invasiva con la técnica de Donald Nuss.

El Pectus excavatum, es una malformación congénita de la pared anterior del tórax, caracterizada por una depresión del esternón. Objetivo: Evaluar los resultados del tratamiento quirúrgico en pacientes con pectus excavatum, utilizando la técnica de Nuss. Material y métodos: Diez pacientes con Pectus excavatum, de 6 a 22 años, operados, fueron incluidos. El seguimiento fue de 2 a 14 meses. Resultados: La edad promedio fue 11,5 años, ocho fueron varones, seis tuvieron pectus excavatum simétrico, el Índice de Haller promedio fue 5,1. La indicación de cirugía fue sintomatología broncopulmonar en 4, cuatro cardiológica, uno psicológico y otro recidiva de pectus Post-Ravitch. En todos los pacientes se implantó una barra metálica con dos estabilizadores, el tiempo operatorio fue entre 2 y 4 horas y la estancia hospitalaria, 7 días. Tres pacientes presentaron complicaciones postoperatorias: neumotórax en dos y en uno fijación inadecuada; en el seguimiento los pacientes no fueron asintomáticas y todos mostraron satisfacción con el tratamiento. Conclusiones: La técnica de Donald Nuss es un procedimiento que corrige el Pectus Excavatum, reduce el tiempo operatorio y estancia hospitalaria, con presentación de complicaciones menores y resultados clínico-psicológicos satisfactorios.(Rev Med Hered 2011;22:108-114)