125 research outputs found
Estudio de viabilidad para una central hidroeléctrica reversible en el embalse del Molinar. T,M. Villa de Ves (Albacete)
[ES] El trabajo fin de grado consiste un estudio de viabilidad técnico, económico y medioambiental para la construcción de una central hidroeléctrica reversible en el embalse del Molinar, en el municipio de Villa de Ves, provincia de Albacete. El río Júcar, en su curso medio a su paso por la comarca albaceteña de la Manchuela, genera un terreno muy escarpado, en el cual por las condiciones del terreno es posible plantearse la construcción de este tipo de centrales hidroeléctricas. Se pretende estudiar la construcción de una balsa en el margen derecho del embalse, para aprovechar el desnivel de unos 245 metros para un ciclo reversible puro con un caudal equipado a determinar según la capacidad de regulación en Molinar.
El proceso de descarbonización que es necesario llevar a cabo para por potenciar el uso de las energías renovables, aunque uno de los principales problemas que existen es el almacenamiento masivo de energía, algo que solo es capaz de hacer la energía hidroeléctrica mediante el almacenamiento de agua. Una central hidroeléctrica reversible funciona como una batería, acumula agua bombeándola hacia el depósito superior en las horas de menor demanda energética y turbinándola hacia el depósito inferior y generar electricidad para cubrir los momentos de mayor demanda.[EN] This Final Dregree Project consists of a technical, economic and environmental feasibility study for the construction of a reversible hydroelectric power plant in the Molinar reservoir, in the municipality of Villa de Ves, province of Albacete. Jucar river, in its middle course as it passes throug the región of La Manchuela in Albacete, generates a steep terrain, in which the construction of a reversible hydroelectric power plants can be considered by the conditions of the land. The aim is to build a accumulation pond on the right bank of the reservoir, to take advantage of the 245 meters slope. The decarbonised process needs to increase the use of renewable energy. One of the main problems that exist it s the massive storage of energy, somethint that only hydroelectric energy can do by storing wáter. A reversible hydroelectric power plant works like a battery, accumulates wáter pumpung it to the upper reservoir in the hours of least energy and turbine it in the hours of greatest demand.Alarcón Mínguez, JM. (2020). Estudio de viabilidad para una central hidroeléctrica reversible en el embalse del Molinar. T,M. Villa de Ves (Albacete). http://hdl.handle.net/10251/151911TFG
Proporciones aúreas de la mezquita del Cristo de la Luz
Con el objeto de favorecer la formación de los alumnos y reducir al mínimo el trauma que supone cada examen, en la cátedra de Construcción que D. Román Ferreras imparte en la E.I.T.O.P., se solicita de aquellos la presentación de un estudio, que al suponer trabajo personal tiene gran repercusión en la calificación final. De entre los realizados últimamente hemos seleccionado el presente, que contiene aportaciones de indudable interés al conocimiento de nuestro acervo arquitectónico y refleja las posibilidades del análisis armónico como herramientas de diseño
A qualidade do sémen e toxicidade de metais pesados e pesticidas
Male reproductive function has deteriorated significantly in the past 50 years and this change could be related to an exposure to occupational and environmental pollutants and toxicants. The purpose of this paper is to summarize the negative impact of human exposure to heavy metals and pesticides on the male reproductive function. Most pesticides and heavy metals are considered reproductive toxicants and may adversely harm the male reproductive system due to their disrupting effect on the hypothalamus- pituitary gland-gonads axis or by directly affecting spermatogenesis, resulting in impaired semen quality. The negative effects of these compounds have been linked to the main sperm parameters (concentration, normal morphology and motility, semen volume and total sperm count) and DNA sperm damage, as well as to changes in serum reproductive hormone levels. Some of these substances have already been banned, whereas others are still on the market. Stricter laws are needed to completely prevent exposure to these toxicants given their proven deleterious effect on male reproductive health.La función reproductiva masculina se ha visto deteriorada significativamente en los últimos 50 años y dicha alteración podría estar relacionada con la exposición a diferentes tóxicos y contaminantes ocupacionales y ambientales. El objetivo de este trabajo es resumir el impacto de la exposición humana a metales pesados y plaguicidas sobre la función reproductiva masculina. La mayoría de los plaguicidas y metales pesados se consideran tóxicos reproductivos y podrían afectar negativamente al sistema reproductivo masculino debido al efecto alterador sobre el eje hipotálamo-pituitario-gonadal, o directamente afectando a la espermatogénesis, dando lugar a una alteración de la calidad seminal. Los efectos negativos de estos compuestos se han relacionado con los principales parámetros espermáticos (concentración, morfología y movilidad normal, volumen seminal y recuento total espermático), alteración del ADN espermático, así como con cambios en los niveles de hormonas reproductivas. El uso de algunas de estas sustancias ya está prohibido mientras que se continúa comercializando con otras. Sería recomendable una legislación más severa que impida cualquier exposición a este tipo de tóxicos debido a su confirmado efecto perjudicial sobre la salud reproductiva masculina.A função reprodutiva masculina tem-se deteriorado significativamente ao longo dos últimos 50 anos e essa alteração pode estar relacionada com a exposição a diferentes tóxicos e contaminantes ocupacionais e ambientais. O objetivo deste artigo é resumir o impacto da exposição humana a metais pesados e pesticidas na função reprodutiva masculina. Considera-se que a maioria dos pesticidas e metais pesados tem um efeito de toxicidade reprodutiva e podem afetar negativamente o sistema reprodutor masculino, devido às alterações que provocam no eixo hipotalámico-hipofisário-gonadal ou ao efeito direto na espermatogénese diminuindo a qualidade seminal. Os efeitos negativos destes compostos têm sido associados com os principais parâmetros do esperma (concentração, morfologia e mobilidade normal, volume seminal e contagem total de espermatozoides), alteração do ADN espermático, bem como as variações nos níveis de hormonas reprodutivas. O uso de algumas dessas substâncias já é proibido contudo outras continuam ainda a poder ser comercializadas. Seria aconselhável legislação mais rigorosa para evitar qualquer exposição a estes tóxicos devido ao seu efeito prejudicial confirmado na saúde reprodutiva masculina
A ingestão de álcool e qualidade do sêmen em homens jovens saudáveis
Over the past 50 years it has been suggested a worldwide decline in human semen quality, probably being lifestyles one of the main factors concerned. Our objectives are to describe semen quality and alcohol consumption in young university students and to explore the associations between alcohol intake and semen quality in young healthy men. A cross-sectional study was carried out between 2010 and 2011 in the Murcia Region (Spain) and included healthy young university students between 18-23 years of age. Two hundred and nine men completed questionnaires on lifestyle and diet, undertook a physical and andrological examination and provided a semen sample. Descriptive statistics are presented using untransformed data. Multiple linear regression analyses were performed to analyze the associations between alcohol intake and semen quality in young men. The median (interquartile range: IQR) values for semen parameters were 42.9 x 106/mL (IQR: 21.9-72.2 x 106/mL) for sperm concentration, 8.9 % (IQR: 6.0-13.9 %) for morphologically normal sperm, and 57.2 % (IQR: 50.7-63.8 %) for sperm motility (progessive and non-progressive). There were no significant associations between alcohol consumption and any sperm parameters. Our results do not support the hypothesis that alcohol intake is related with sperm quality parameters probably due to the low alcohol consumption range in our population of healthy, unselected young men. In conclusion, moderate alcohol consumption is not associated with semen quality in young university students of Murcia Region (Spain).En los últimos 50 años se ha sugerido una disminución global de la concentración espermática humana, siendo los hábitos de vida uno de los principales determinantes señalados. El objetivo de este estudio es describir el consumo de alcohol y la calidad seminal en jóvenes varones universitarios e investigar las asociaciones entre ambas características. Se trata de un estudio transversal que se llevó a cabo en la Región de Murcia (España) entre 2010 y 2011. Los participantes fueron jóvenes universitarios sanos entre 18 y 23 años. Doscientos nueve varones cumplimentaron cuestionarios sobre hábitos de vida y alimentación, se sometieron a un examen físico y andrológico y proporcionaron una muestra seminal. Los estadísticos descriptivos se muestran como datos crudos. Para analizar las asociaciones entre consumo de alcohol y calidad seminal se realizaron análisis de regresión lineal múltiple. Los valores de la mediana y rango intercuartil (RIC) de los parámetros seminales analizados fueron los siguientes: 42,9 x 106/mL (RIC: 21,9-72,2 x 106/mL) de concentración espermática, 8,9 % (RIC: 6,0-13,9 %) de espermatozoides morfológicamente normales, y 57,2 % (RIC: 50,7-63,8 %) de movilidad espermática (progresiva y no progresiva). No se encontraron asociaciones significativamente estadísticas entre el consumo de alcohol y los distintos parámetros seminales. Nuestros resultados no respaldan la hipótesis de que la ingesta de alcohol esté relacionada con la calidad seminal, probablemente debido al bajo rango de consumo de alcohol en nuestra población de estudio. En conclusión, el consumo moderado de alcohol no está relacionado con la calidad seminal en jóvenes universitarios sanos de la Región de Murcia.Nos últimos 50 anos tem sugerido uma diminuição global da concentração de esperma humano e os estilos de vida foram identificados com um dos principais determinantes. O objetivo deste estudo é descrever o consumo de álcool e a qualidade do sémen em jovens universitários e investigar as associações entre estas duas características. Trata-se de um estudo transversal realizado na Região de Múrcia (Espanha) entre 2010 e 2011. Os participantes foram estudantes universitários saudáveis, com idades compreendidas entre os 18 e os 23 anos. Duzentos e nove rapazes responderam aos questionários sobre hábitos de vida e alimentação; submeteram-se a um exame físico e andrológico e forneceram uma amostra de sémen. Os resultados da estatística descritiva foram apresentados com dados brutos. Para analisar as associações entre o consumo de álcool e a qualidade do sémen, realizou-se a análise através de regressão linear múltipla. Os valores de mediana e o intervalo interquartil (IQR) em parâmetros do sémen analisados foram os seguintes: 42,9 x 106/mL (IQR, 21,9-72,2 x 106/mL) de concentração de espermatozóides, de 8,9 % (IQR, 6,0-13,9 %) de espermatozóides morfologicamente normais e 57,2 % (IQR, 50,7-63,8 %) da motilidade de espermática (progressiva e não progressiva). Não foram encontradas associações estatisticamente significativas entre o consumo de álcool e os vários parâmetros do esperma. Os nossos resultados não apoiam a hipótese de que o consumo de álcool esteja relacionado com a qualidade do sémen, provavelmente devido ao baixo consumo de álcool na população em estudada. Conclui-se que o consumo moderado de álcool não está relacionado com a qualidade do sémen nos jovens saudáveis da universidade da Região de Murcia
Correlations between Different Heavy Metals in Diverse Body Fluids: Studies of Human Semen Quality
It has been hypothesized that exposure to heavy metals may impair male reproduction. To measure the effect produced by low doses of heavy metals on semen parameters, it is necessary to clarify in which body fluids those measurements must be performed. Sixty-one men attending infertility clinics participated in our study. Concentrations of lead, cadmium, and mercury were measured in whole blood, blood plasma, and seminal plasma using spectroanalytical and electrochemical methods. Semen analyses were performed according to World Health Organization criteria. For statistical analysis, Spearman's rank correlations, mean comparison tests, and discriminant analysis were calculated. Significant correlations between the measured concentrations of the three heavy metals in the same biological fluids were observed. However, no similar relationship was seen when comparing the concentrations in different body fluids of the same metal. According to our results and previous publications, seminal plasma might be the best body fluid for assessing impairment of human semen parameters
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A Longitudinal Study of Peripubertal Serum Organochlorine Concentrations and Semen Parameters in Young Men: The Russian Children’s Study
Background: Exposures to endocrine-disrupting chemicals during critical phases of testicular development may be related to poorer semen parameters. However, few studies have assessed the association between childhood organochlorine (OC) exposure and adult semen parameters. Objective: We examined whether peripubertal serum OC concentrations are associated with semen parameters among young Russian men. Methods: From 2003 through 2005, 516 boys were enrolled at age 8–9 years and followed for up to 10 years. Serum OCs were measured in the enrollment samples using high-resolution mass spectrometry. At 18–19 years, 133 young men provided 1 or 2 semen samples (256 samples) collected approximately 1 week apart, which were analyzed for volume, sperm concentration, and motility. Unadjusted and adjusted linear mixed models were used to examine the associations of quartiles of lipid-standardized concentrations of dioxins [2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), polychlorinated dibenzo-p-dioxins (PCDDs)], furans, polychlorinated biphenyls (PCBs), and corresponding toxic equivalents (TEQs) with semen parameters. Results: The median (range) for TCDD was 2.9 (0.4–12.1) pg/g lipid and PCDD TEQ was 8.7 (1.0–36.0) pg TEQ/g lipid. Higher quartiles of TCDD and PCDD TEQs were associated with lower sperm concentration, total sperm count, and total motile sperm count (p-trends ≤ 0.05). The highest quartile of peripubertal serum TCDD concentrations was associated with a decrease (95% CI) of 40% (18, 66%), 29% (3, 64%), and 30% (2, 70%) in sperm concentration, total sperm count, and total motile sperm count, respectively, compared with the lowest quartile. Similar associations were observed for serum PCDD TEQs with semen parameters. Serum PCBs, furans, and total TEQs were not associated with semen parameters. Conclusion: Higher peripubertal serum TCDD concentrations and PCDD TEQs were associated with poorer semen parameters. Citation: Mínguez-Alarcón L, Sergeyev O, Burns JS, Williams PL, Lee MM, Korrick SA, Smigulina L, Revich B, Hauser R. 2017. A longitudinal study of peripubertal serum organochlorine concentrations and semen parameters in young men: the Russian Children’s Study. Environ Health Perspect 125:460–466; http://dx.doi.org/10.1289/EHP2
Peripubertal serum concentrations of organochlorine pesticides and semen parameters in Russian young men.
BACKGROUND: Epidemiologic literature on the relation of organochlorine pesticides (OCPs) with semen quality among adult men has been inconclusive, and no studies have prospectively explored the association between peripubertal serum OCPs and semen parameters in young men.
OBJECTIVE: To evaluate prospective associations of peripubertal serum concentrations of hexachlorobenzene (HCB), β-hexachlorocylohexane (β-HCH), and p,p\u27-dichlorodiphenyldichloroethylene (p,p\u27-DDE) with semen parameters among young Russian men.
METHODS: This prospective cohort study included 152 young men who enrolled in the Russian Children\u27s Study (2003-2005) at age 8-9 years and were followed annually until young adulthood. HCB, β-HCH, and p,p\u27-DDE concentrations were measured at the CDC by mass spectrometry in serum collected at enrollment. Between 18 and 23 years, semen samples (n = 298) were provided for analysis of volume, concentration, and progressive motility; we also calculated total sperm count and total progressive motile count. Linear mixed models were used to examine the longitudinal associations of quartiles of serum HCB, β-HCH and p,p\u27-DDE with semen parameters, adjusting for total serum lipids, body mass index, smoking, abstinence time and baseline dietary macronutrient intake.
RESULTS: Lipid-adjusted medians (IQR) for serum HCB, βHCH and p,ṕ-DDE, respectively, were 150 ng/g lipid (102-243), 172 ng/g lipid (120-257) and 275 ng/g lipid (190-465). In adjusted models, we observed lower ejaculated volume with higher serum concentrations of HCB and βHCH, along with reduced progressive motility with higher concentrations of βHCH andp,ṕ-DDE. Men in the highest quartile of serum HCB had a mean (95% Confidence Interval, CI) ejaculated volume of 2.25 mL (1.89, 2.60), as compared to those in the lowest quartile with a mean (95% CI) of 2.97 mL (2.46, 3.49) (p = 0.03). Also, men in the highest quartile of serum p,ṕ-DDE had a mean (95% CI) progressive motility of 51.1% (48.6, 53.7), as compared to those in the lowest quartile with a mean (95% CI) of 55.1% (51.7, 58.5) (p = 0.07).
CONCLUSION: In this longitudinal Russian cohort study, peripubertal serum concentrations of selected OCPs were associated with lower ejaculated volume and progressive motility highlighting the importance of the peripubertal window when evaluating chemical exposures in relation to semen quality
The association between animal flesh foods consumption and semen parameters among infertile Iranian men:a cross-sectional study
Synergism between the N-acetyltransferase 2 gene and oxidant exposure increases the risk of idiopathic male infertility
The diagnosis of male infertility:an analysis of the evidence to support the developments of global WHO guidance. Challenges and future research opportunities
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