3,837 research outputs found
X-Ray Fluorescence Analysis of Ground Coffee
Coffee is becoming one of the most popular beverages in Mexico. In the present work, X-ray Fluorescence (XRF) was used to determine the contents of several elements (with atomic numbers between 11 and 38) in 11 samples of commercial ground coffee, comparing with another one of soluble coffee and two of used ground coffee. Samples were dried at room temperature and pelletized. XRF analyses were carried out using a spectrometer based on an Rh X-ray tube, registering the characteristic x-rays with a Silicon Drift Detector. The system detection calibration and accuracy check was performed through the analysis of NIST certified reference materials 1547 (peach leaves), 1570a (spinach leaves), 1573a (tomato leaves), and 1571 (orchid leaves). As a general rule, the elemental concentrations measured are similar in all samples of coffee, in values not exceeding toxic levels. However, the differences among the elemental concentrations are shown
El desarrollo de la expresión escrita en la Universidades de Madrid: los trabajos fin de grado en los estudios de ADE
Ante la preocupación generalizada de la sociedad acerca de las carencias de los jóvenes en cuanto a la expresión escrita, el presente artículo tiene como objetivo analizar si esta competencia se desarrolla y se evalúa en la Universidad. La comunidad académica no puede permanecer ajena a este problema, por lo que es importante que incluya dentro de sus planes de estudio la mejora de esta competencia. El desarrollo de la expresión escrita se incluye entre las competencias generales instrumentales para el aprendizaje y la formación. Se considera, por tanto, una competencia necesaria para cualquier tipo de
estudio y cualquier perfil profesional. En particular, en los estudios de ADE, la adquisición de la expresión escrita no se circunscribe a ninguna asignatura en concreto, sino que puede desarrollarse en varias de ellas a lo largo de la titulación. No obstante, el Trabajo de Fin de Grado es una de las asignaturas en la que mejor puede enmarcarse la consecución de esta habilidad. Por este motivo, se
realiza un análisis sobre el diseño, la organización, el contenido y la evaluación del Trabajo de Fin de Grado en todas las universidades de la Comunidad de Madrid, tanto públicas como privadas, en las que se imparte el Grado en Administración y Dirección de Empresas. El estudio se ha elaborado a partir de la información de los planes de estudio y de las guías docentes de la asignatura, disponibles en las páginas web de las universidades
Propuesta de una investigación participativa para la asignatura ¿Administración de la empresa familiar?: utilización del análisis comparativo y la entrevista en profundidad
En este estudio se expone una de las actividades llevadas a cabo en la asignatura “Administración de la Empresa Familiar”. Esta práctica se realiza utilizando distintas metodologías docentes afines al Espacio Europeo de Educación Superior: la lección magistral, el estudio de casos y el aprendizaje cooperativo, combinando además estos métodos con un análisis comparativo entre empresas y la técnica de la entrevista en profundidad. El objetivo perseguido es acercar al estudiante a la realidad empresarial que le rodea, en el que el 85 1 por ciento de las empresas son familiares. Se pretende que el estudiante comparta experiencias y se integre durante unas horas en una empresa familiar para que conozca su funcionamiento y pueda aplicar, en la práctica, lo que en teoría se explica en el aula. Además, se intenta que la búsqueda de información sobre la empresa elegida, el contacto que el estudiante mantenga en la entrevista así como la elaboración del informe que el estudiante tendrá que elaborar después, despierte en el alumno el interés por la investigación
Analytical study on ethephon residue determination in water by ion-pairing liquid chromatography/tandem mass spectrometry
A detailed analytical study on ethephon residue determination in water, making use of ion-pairing liquid chromatography coupled to electrospray tandem mass spectrometry (LC/MS/MS), has been carried out. Ethephon is a plant growth regulator, highly polar, which is typically present in aqueous solution in anionic form due to its acid character. Both its extraction and pre-concentration from water samples and its chromatographic retention are difficult. Several approaches for sample pretreatment have been tested including direct injection into the chromatographic system, on-line solid phase extraction (SPE) and off-line SPE, with the best results being obtained after off-line SPE, using Oasis MAX cartridges (mixed-mode strong anion-exchange). After testing several ion-pairing reagents, tetrabuthylammonium acetate (TBA) was selected. This was added to the samples before LC/MS/MS analysis to facilitate ethephon chromatographic retention. The acquisition of several specific MS/MS transitions together with the evaluation of their relative intensity ratios allowed the reliable confirmation of the analyte in samples. The optimised approach was tested in low-salinity water spiked at 0.1 µg L−1 level with satisfactory recovery, and a limit of detection of 0.02 µg L−1. To this purpose, the water sample was partially de-ionised in an initial stage, in order to remove major ions that would have interfered in analyses. The application of this methodology to more saline/complex water samples, as surface or wastewater, was problematic and a thorough optimisation of the de-ionisation conditions would be required
Study of cyanotoxin degradation and evaluation of their transformation products in surface waters by LC-QTOF MS
In the present work, the degradation of three cyanotoxins from the hepatotoxins group was investigated under laboratory-controlled experiments in water samples. Surface waters spiked with microcystin-LR (MC-LR), nodularin (NOD) and cylindrospermopsin (CYN) were subjected to hydrolysis, chlorination and photo-degradation, under both sunlight (SL) and ultraviolet (UV) radiation. A total of 12 transformation products (TPs) were detected and tentatively identified by liquid chromatography coupled to quadrupole time-of-flight mass spectrometry (LC-QTOF MS). These comprised: 6 chlorination TPs (3 from CYN and 3 from MC-LR, 2 isomers); 4 UV TPs (all from CYN); and 2 sunlight TPs (one isomer from MC-LR and another from NOD). No TPs were observed under hydrolysis conditions. The chemical structures for all TPs were tentatively proposed based on the accurate-mass QTOF MS full-spectra. Analysis of real-world samples collected from the Peñol reservoir (Antioquia, Colombia) revealed the presence of MC-LR and CYN as well as a sunlight TP identified in the laboratory experiments. Data presented in this article will assist further research on TPs potentially formed in future tertiary degradation processes applied for the removal of organic micro-pollutants in water; as well as improving available knowledge on the toxic implications of cyanobacterial toxins TPs in surface waters
Analysis of the sports career of brazilian international elite squash athletes
A carreira esportiva é um processo onde o atleta, de forma voluntária, busca atingir níveis elevados de desempenho esportivo, entretanto não se conhece sobre como ocorreu o desenvolvimento da carreira esportiva em atletas de squash. O objetivo foi analisar a trajetória esportiva de atletas brasileiros de squash de nível internacional em diferentes momentos da carreira esportiva. Utilizando o Quadro de Desenvolvimento de Valores Pessoais no Esporte como base, realizamos entrevista semiestruturada com seis atletas (três do sexo masculino e três do sexo feminino), e empregamos para a análise das entrevistas a Análise Temática. Os resultados encontrados foram que os temas características pessoais, relações interpessoais e o contexto de prática esportiva são temas que possibilitam o desenvolvimento da carreira esportiva de atletas de squash. De modo conclusivo os três aspectos, atuando de forma concomitante, possam ofertar, de modo favorável, o desenvolvimento de atletas de squash de nível internacional.The sports career is a process where the athlete, voluntarily, seeks to achieve high levels of sports performance, however it is not known about how the development of the sports career occurred in squash athletes.The aim of this study was to analyze the sports life trajectory of Brazilian squash athletes in different periods of the sports career. Using the Personal Assets Framework (P.A.F.) as a base, we conducted a semi-structured interviews for six athletes (three male athletes and three female athletes), and used a thematic analysis for the interviews. The results showed themes like personal traits, interpersonal relations and the context of the sport practice are themes that allow the development of the sports career of squash athletes. Conclusively that the three aspects, acting concurrently, can favorably favor the development of international squash athletes
Evolución histórica de los vehículos aéreos no tripulados hasta la actualidad
The origin and development of unmanned aviation has been almost matched that of manned aviation, starting both from an almost common point. As in conventional manned aviation, military applications, have been the motor of technological development and the potential applications of these types of systems throughout much of the twentieth century and early twenty-first century. Finally it has been in relatively recent times that these systems are experiencing an impressive boom due to the discovery of the wide variety of commercial and civil operations that are able to perform very effectively. This paper attempts to summarize the historical evolution that these systems have suffered and in the end, to present a quick analysis of the major civil / commercial applications, trying to provide an overview of the main types of systems, their classification and general configuration.Peer Reviewe
Prevalence and molecular identification of Chlamydia abortus in commercial dairy goat farms in a hot region in Mexico
The aim of this study was to determine the seroprevalence and presence of Chlamydia abortus in Saanen breed female goats from commercial dairy goat farms under intensive production in the municipality of Guanajuato, Mexico. Sera were collected to determine the prevalence of anti-C. abortus IgG antibodies using recombinant enzymelinked immunosorbent assay (rELISA) and cell culture. Polymerase chain reaction (PCR) was used to prove the presence of the pathogen in swab samples collected from the vagina and rectum of selected animals. Additionally, foetal tissue samples from a sudden abortion were collected. C. abortus prevalence in female goats of commercial milking farms sampled in Guanajuato, Mexico, was 4.87 % (n=246). Seropositive animals were found in six out of nine (66.6 %) dairy goat farms sampled, and prevalence among animals in individual farms ranged between 3.44 and 13.51 %. C. abortus was detected using PCR in spleen tissue from the aborted foetus. PCR-based detection, as well as isolation from vaginal and rectal swabs, was not possible in the present study. Isolation through cell culture was also unsuccessful from aborted foetal tissue samples. In conclusion, the results from rELISA and PCR show that C. abortus is present in dairy goat farms in the state of Guanajuato, Mexico
Getting Ahead: A Resident Led Quality Improvement Project to Increase Diabetic Nephropathy Screening in an Underserved Hispanic-Predominant Population
Introduction: Diabetes is the leading cause of end-stage renal disease (ESRD) in the United States (US), with 37 million having chronic kidney disease. Despite national guidelines recommendations for diabetic nephropathy screening with urine albumin-to-creatinine ratio (UACR), less than 50% receive full screening.
Our Internal Medicine residents led a quality improvement project to increase diabetic nephropathy screening rate with UACR in our resident clinic by 50% in one academic year.
Methods: We conducted the resident-led quality improvement project from July 2021 to April 2022. We reviewed the electronic medical records (EMR) from our clinic pre-intervention July 2020 to June 2021 and compared this to post intervention July 2021 to March 2022 determining the nephropathy screening rates in patients with diabetes. Our interventions included resident education, pre and post surveys to test foundational knowledge, adding UACR in the affordable laboratory order form and establishing normal reference range of UACR in the EMR.
Results: We collected 217 patients with diabetes, 27% were uninsured, 38% had Medicare/Medicaid and 90% identified as Hispanic. Comparing pre to post intervention, there was a significant change of 45 (20.7%) vs 71 (32.7%) patients screened for diabetic nephropathy with a UACR. The correct average score of knowledge-based questions was 82% on the pre survey, which increased to 88% in the post survey.
Conclusion: Our study showed promising results on improving diabetic nephropathy screening. The comprehensive approach including resident education about diabetic nephropathy screening with UACR and more so facilitating the order set in the EMR were key to achieve this goal
Plan de intervención para la salud e higiene oral de los niños de la institución educativa Félix de Bedout Moreno.
Plan de acción que identifica el estado general de la higiene oral de los niños de 7 a 9 años de los grados segundos de la Institución Educativa Félix de Bedout Moreno del municipio de Medellín con el fin de establecer programas de enseñanza de hábitos que promuevan el mejoramiento de la salud oral de los estudiantes
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