Soldadura blanda

Cartilla que presenta los materiales, herramientas, operaciones, métodos y esquemas para los procesos de: soldadura con estaño y soldadura de tuberías.Primer that presents the materials, tools, operations, methods and schemes for the processes of: tin welding and pipe welding.Materiales -- Orden de operaciones -- Soldadura de estaño -- Generalidades -- Útiles de trabajo -- Soldadura -- Clasificación de los alambres de soldadura -- Cautines -- Cautines electricos -- Selección del tamaño del cautín -- Preparación de las piezas a soldar -- Encendido del soplete -- Estañado del cautín -- Aplicación de la soldadura -- Soldadura de tuberías de refrigeración -- Soldadura de tuberíasnaDocumento elaborado bajo la asesoría O.I.T24 página

Histogram Reweighting Method for Dynamic Properties

The histogram reweighting technique, widely used to analyze Monte Carlo data, is shown to be applicable to dynamic properties obtained from Molecular Dynamics simulations. The theory presented here is based on the fact that the correlation functions in systems in thermodynamic equilibrium are averages over initial conditions of functions of the trajectory of the system in phase-space, the latter depending on the volume, the total number of particles and the classical Hamiltonian. Thus, the well-known histogram reweighting method can almost straightforwardly be applied to reconstruct the probability distribution of initial states at different thermodynamic conditions, without extra computational effort. Correlation functions and transport coefficients are obtained with this method from few simulation data sets.Comment: 4 pages, 3 figure

Dyspepsia: A Great Diagnosis Challenge

La presente es una revisión no sistemática de literatura con la siguiente estrategia de búsqueda: (((((“Dyspepsia” [Mesh] OR “Peptic Ulcer” [Mesh]) OR “Helicobacter pylori” [Mesh]) AND (“Diagnosis”[Mesh] OR (“Therapeutics” [Mesh OR “therapy “[Subheading])) OR “Epidemiology” [Mesh]. La indagación contempló el periodo comprendido entre los años 1966 y 2007. La estrategia de búsqueda fue adaptada a cada una de las bases de datos consultadas: MEDLINE, COCHRANE, LILACS y SCIELO. Se encontraron, por título y abstract, 689 artículos, a criterio de los autores, de los cuales fueron seleccionados 138 para esta revisión. No se obtuvieron 6 artículos por no tener acceso a los correspondientes journals. El propósito de esta revisión es dar a conocer y aclarar algunos puntos sobre el diagnóstico y tratamiento de la dispepsia.We performed a review not systematic of the literature, taking into account the following search strategy: (((((“Dyspepsia” [Mesh] OR “Peptic Ulcer” [Mesh]) OR “Helicobacter pylori” [Mesh]) AND (“Diagnosis”[Mesh] OR (“Therapeutics” [Mesh OR “therapy “[Subheading])) OR “Epidemiology” [Mesh]. Search was conducted between 1966 to 2007. Search strategy was adapted each of the databases consulted MEDLINE, COCHRANE, LILACS and SCIELO. We were selected 689 articles by title and abstract with authors criteria, of whom 138 were selected for this review. 6 articles were not obtained because we didn’t have access to these journals. The aim of this review is to be able to publicize and clarify certain points in the diagnosis and treatment of dyspepsia

Influence of Penile Spicules of Covies(Cavia porcellus)on their Sexual Behavior, Fertility and Sperm Quality

This research took place in canton Cuenca, province of Azuay, Ecuador, located on UTM 717386 x 9675751, 2 714 meters above sea level, with a mean temperature of 14°C. The study determined the influence of penile spicules on sexual behavior, fertility and sperm quality parameters in cavies (Cavia porcellus), raised on the Ecuadoran highlands. A number of 5 whole males (with penile spicules), and other 5 males with their spicules removedwere included in the study, along with 40 nulliparous females, type A, pelage type 1. The pregnancy percentage of females that copulated with extirpated males decreased 65% in relation to the control group (P<0.05). However, the sexual behavior pattern and sperm quality of the two groups in the study were similar (P>0.05). Therefore, the study concluded that extirpation of the penile spicules has effects on fertility, but not on sexual behavior and sperm quality

Aquatic pollution from anthropogenic discharges modulates gene expression in liver of rainbow trout (Oncorhynchus mykiss)

With the aim to characterise the biological impact of anthropogenic discharge in a river, gene expression in fish was evaluated as a biomarker for mixture effects of potential toxic compounds in the aquatic environment. Adult male rainbow trout (Oncorhynchus mykiss) were used as monitoring organisms. Within the German experimental set up, trout were exposed actively for 28 days in biologically purified sewage as well as in river water up- and downstream of the sewage treatment plant (STP) effluent. In a different approach, wild trout were captured in southern Chile near anthropogenic discharges. Fish were taken from river Maullin receiving sewage from a settlement and from river Pescado influenced by effluents from a fish farm. In vivo effects were assessed by RT-qPCR analyses of biomarker gene expression, vitellogenin (vg), metallothionein (mt) and cytochrome 1A (cyp1A) in liver samples with primers amplifying specific sequences previously confirmed by cloning and sequencing. The modulation of expression of marker genes involved in metal stress, reproduction and detoxifying systems in the liver of male rainbow trout revealed organismal response to anthropogenic contamination in two different study areas, such as Chile and Germany, thereby indicating a potential risk on the aquatic ecosystems

Clinicopathologic study on the effects of Glyphosate (Roundup?) at sublethal levels in a murine experimental model

P?ginas 17-24Recurso Electr?nicoEn Colombia, los pesticidas a base de glifosato se usan para el control de malezas en la agricultura y erradicaci?n de cultivos il?citos. Sin embargo, los efectos t?xicos en animales y humanos expuestos a dosis subletales son desconocidos. Este estudio evalu? los efectos cl?nico-patol?gicos de dietas con 7,5 ppm y 15 ppm glifosato en ratones Mus musculus gestantes, usando el herbicida Roundup?. Se registr? el peso corporal de las hembras, de sus cr?as, y la viabilidad de las camadas diariamente. Las lesiones macrosc?picas e histopatol?gicas en el h?gado, ri??n, ?tero y cerebro se determinaron a trav?s de necropsias en los d?as 5, 30 y 45 despu?s de la exposici?n, adem?s de los ?ndices org?nicos hep?tico y cardiaco. No hubo diferencias significativas en el peso corporal, el tama?o y la viabilidad de las camadas a ninguna de las dosis evaluadas. Se observ? congesti?n y aumento en el tama?o del h?gado, ri??n y bazo, despu?s de 5 d?as de exposici?n, sugiriendo un proceso de desintoxicaci?n. A 30 y 45 d?as, no se observaron signos cl?nicos ni lesiones patol?gicas atribuibles al glifosato; sin embargo, un aumento en el tama?o de los hepatocitos, con contenido vacuolar y granular de aspecto protein?ceo indican un efecto evidente, aunque sutil del Roundup? a dosis subletales con posible adaptabilidad org?nica. Se concluye que el consumo de alimento con 7,5 ppm y 15 ppm de glifosato durante 5, 30 y 45 d?as causa alteraciones sutiles de toxicidad en ratones durante la gestaci?n, la lactancia y el posparto, pero no en sus camadas.ABSTRACT. In Colombia, glyphosate-based pesticides are used for weed control in agriculture and eradication of illicit crops; however, the toxic effects in animals and humans exposed to sublethal doses are unknown. This study evaluated the clinical and pathological changes induced by diets containing glyphosate at 7,5 ppm and 15 ppm in pregnant mice Mus musculus, using the herbicide Roundup ?. The body-weight of pregnant females and offspring and the viability of litters were recorded daily. Gross and microscopic lesions in liver, kidney, uterus and brain were determined at necropsies performed at 5, 30 and 45 days post- exposure, in addition to the liver and heart organic indexes. No significant differences were found in body weight, size and viability of litters at any dose. Organs such as the liver, kidney and spleen were enlarged and congested at day 5 post exposure, suggesting a detoxification process. At 30 and 45 days, no clinical signs or pathological lesions attributed to glyphosate were found. However, there was an increase in the hepatocyte size, with vacuolar and granular cytoplasm and proteinaceus-like content, suggesting a subtle effect of sublethal doses of Roundup ?, with possible organ adaptability. We conclude that the consumption of food containing 7.5 ppm and 15 ppm of glyphosate for 5, 30 and 45 days, cause subtle toxic alterations in mice during pregnancy, lactation and postpartum, but not in their litters

A Radical Mechanism for the Vanadium-Catalyzed Deoxydehydration of Glycols

We propose a novel mechanism for the deoxydehydration (DODH) reaction of glycols catalyzed by a [Bu4N][VO2(dipic)] complex (dipic = pyridine-2,6-dicarboxylate) using triphenylphosphine as a reducing agent. Using density functional theory, we have confirmed that the preferred sequence of reaction steps involves reduction of the V(V) complex by phosphine, followed by condensation of the glycol into a [VO(dipic)(-O-CH2CH2-O-)] V(III) complex (6), which then evolves to the alkene product, with recovery of the catalyst. In contrast to the usually invoked closed-shell mechanism for the latter steps, where 6 suffers a [3+2] retrocycloaddition, we have found that the homolytic cleavage of one of the C–O bonds in 6 is preferred by 12 kcal/mol. The resulting diradical intermediate then collapses to a metallacycle that evolves to the product through an aromatic [2+2] retrocycloaddition. We use this key change in the mechanism to propose ways to design better catalysts for this transformation. The analysis of the mechanisms in both singlet and triplet potential energy surfaces, together with the location of the MECPs between them, showcases this reaction as an interesting example of two-state reactivity.Xunta de Galicia and Ministerio de Economiá y Competitividad for funding through Projects EM2014/040 and CTQ2013-48937-C2-1-P and CTQ2013-48937-C2-2-P, respectively. R.S. thanks the Junta de Castilla y León for funding through projects BU237U13 and BU076U16

Microplastics in sediments of artificially recharged lagoons: case study in a Biosphere Reserve

We studied the occurrence of microplastics in sediments of artificially and non-artificially recharged lagoons from the network of endorheic wetlands called “La Mancha Húmeda”, declared Biosphere Reserve by UNESCO. The particles sampled in this study covered the 25 μm–5 mm range. Films were the dominant microplastic typology in non-artificially recharged lagoons, while fibres and fragments were more abundant in those receiving wastewater. The concentration of microplastics in sediments reached up to 24.4 ± 5.2 microplastics/g, while plastic litter counts yielded <1 particle/g in non-wastewater receiving lagoons. Eleven types of plastic were identified using Micro-Fourier Transform Infrared Spectroscopy (micro-FTIR), the most abundant being the polyolefins polyethylene and polypropylene, and polyester and acrylic fibres. The statistical analysis of FTIR spectra confirmed the similarity between samples taken from recharged lagoons and wastewater treatment plant effluents. Overall, our results showed that endorheic lagoons are very sensitive to the accumulation of persistent pollutants, which include microplastics. The recharge of lagoons with wastewater effluents to maintain water levels, even if correctly treated according to current standards, is not a sustainable practice. Due to the closed character of endorheic basins, the continuous input of wastewater led to the accumulation of microplastics in sediments of wastewater receiving lagoons up to 40 times over non-recharged lagoon

Removal of Penile Spicules of Covies (Cavia porcellus) and its Effect on Weight Gain and Aggressiveness

This research took place on Irquis Farm, University of Cuenca, Victoria del Portete parish, Cuenca canton, prov-ince of Anzuay, Ecuador. The effects of penile spicule extirpation on weight gain and aggressiveness, and damage caused to the carcass at the beginning of growing/fattening were studied. The study consisted of three treatments: whole animals without castration, used as controls (T1); animals with extirpation of the glans´s spicules (T2); and chemically castrated animals, using 0.5 ml of 2% alcohol with iodine, directly injected in each testicle (T3). A total of 90 animals were included, following a randomized block design with six treatments and five replicas. The diet consisted of forage mixture of 33-35% dry matter, and a commercial feed supplement administered ad libitum. A co-variance analysis (ANACOVA) was made using the initial weight as co-variable. The final weight was significantly influenced by the treatment; the Tukey´s test resulted in higher final weight in T2, followed by T1. Their behavior was significantly different from T3 (P &lt; 0.05). In relation to aggressiveness expressed in carcass damage, no signifi-cant differences were observed, according to Chi-square test (P &gt; 0.05)

Prevalencia de sarcopenia en adultos mayores de dos hogares geriátricos de Pereira, Colombia: Prevalence of sarcopenia in older adults in two retirement homes in Pereira, Colombia

Introduction: Is a risk factor for morbidity, mortality and disability in older adults, so its management is a priority in geriatrics. The aim of this article is to characterize a population of older adults from two geriatric homes and to establish the prevalence of sarcopenia and the degree of dependence. Methods: Cross-sectional study developed in the city of Pereira-Colombia. A population of 72 adults from 65 to 98 years of age was included, using probability sampling. Sarcopenia was determined by means of the Criteria of the European Consensus on Definition and Diagnosis of Sarcopenia, evaluating grip strength, skeletal muscle mass index, in case of sarcopenia, the severity of sarcopenia together with walking speed, and the degree of dependence according to the Barthel scale.&nbsp; Results: 57 people participated. A total of 68.4% (n=39) were women. The median age was 83 years. Two percent had no sarcopenia, 9% had suspected sarcopenia, 28% had confirmed sarcopenia and 61% had severe sarcopenia. According to the Barthel scale, 31.5% were independent, 45.6% had mild, 15.8% moderate, 5.3% severe and 1.8% total dependence. Conclusions: The prevalence of sarcopenia in nursing homes in Pereira is higher compared to that reported in the literature. Similarly, being in a private nursing home does not guarantee a better physical condition and/or quality of lifeIntroducción: La sarcopenia es un factor de riesgo para morbilidad, mortalidad y discapacidad en adultos mayores, por lo que su manejo es prioridad en geriatría. El objetivo de este artículo, consiste en caracterizar una población de adultos mayores de dos hogares geriátricos y establecer la prevalencia de sarcopenia y el grado de dependencia. Métodos: Estudio de corte transversal desarrollado en la ciudad de Pereira-Colombia. Se incluyó a una población de 72 adultos desde los 65 hasta los 98 años, usando muestreo probabilístico. Se determinó la sarcopenia por medio de los Criterios del Consenso Europeo sobre Definición y Diagnóstico de Sarcopenia; evaluándose la fuerza de prensión, índice de masa muscular esquelética, en caso de presentarse sarcopenia, la severidad de esta junto a la velocidad de marcha, y el grado de dependencia según la escala de Barthel. Resultados: Participaron finalmente 57 personas. El 68,4% (n=39) eran mujeres. La mediana de la edad fue de 83 años. El 2% no presentó sarcopenia, 9% presentaban sospecha de sarcopenia, 28% tenían sarcopenia confirmada y 61% sarcopenia grave. Según la escala de Barthel, el 31,5% eran independientes, 45,6% tenían dependencia leve, 15,8% moderada, 5,3% severa y 1,8% total. Conclusiones: La prevalencia de sarcopenia en los hogares geriátricos de Pereira es mayor en comparación a la reportada en la literatura. Del mismo modo, encontrarse en un hogar geriátrico privado no garantiza una mejor condición física y/o calidad de vida