Reliability ofwood utility poles under stochastic wind load and material considering knots

Wood utility poles are simple structures used in power networks and their failure may produce a significant impact on their reliability as well as economic consequences. Wind loads are one of the main causes of damage in wood utility poles. The present study addresses the dynamic behavior of Argentinean Eucalyptus grandis wood poles with uncertain material properties under stochastic wind load. Regarding the material, the lengthwise variability of the Modulus of Elasticity (MOE) and the second moment of area are simulated through the Weak Zone (WZ) model taking into account the knots presence. The stochastic wind velocity field is derived using the Spectral Representation Method (SRM) considering temporal and spatial correlation. Then, the wind load is obtained under the considerations of the Argentinean standard CIRSOC 102. The governing equations are discretized through the Finite Element Method (FEM). The stochastic analysis is performed by means of Monte Carlo Simulations (MCS). In this study, displacements are evaluated such that a percentage of damage is found for each wind velocity. Fragility curves are a useful means to evaluate the failure probability of the poles for a defined failure mode, under a given range of demand, here the wind load. The WZ model results are compared with other MOE models previously developed (as a random variable and as a random field through the Non Gaussian Karhunen-Loève Expansion). Also, confidence bands of the fragility curves are obtained for 95% of confidence.Publicado en: Mecánica Computacional vol. XXXV, no. 21Facultad de Ingenierí

El respeto a los derechos de las mujeres y las niñas salvadoreñas, frente a la violencia de género en El Salvador, en el marco de la meta: eliminar todas las formas de violencia, periodo 2009-2018

El presente trabajo de grado se enfoca en estudiar el contexto de derechos de las mujeres y niñas salvadoreñas en el territorio, basándose en las administraciones del ex presidente Mauricio Funes, así como del ex presidente Salvador Sánchez Cerén, en cuanto a la gestión de acciones encaminadas a eliminar la violencia de género con la finalidad de mejorar las condiciones de vida de las mujeres. Este trabajo expone las formas de violencia, las barreras principales que han perjudicado el logro de avances importantes en beneficio de los derechos de las mujeres y niñas, y por tanto en favor de la construcción de una sociedad más equitativa. De esta manera, se han podido identificar factores que deben ser áreas de atención en la incorporación de iniciativas que generen las condiciones de igualdad en la sociedad salvadoreña, así como procuren el desarrollo de conductas de respeto hacia los derechos de las mujeres y niñas y su concientización respeto al tema. Es así que se evalúa no únicamente el establecimiento de legislaciones encargadas de la protección de los derechos femeninos, sino la inclusión de los actores de sus entornos, su familia, refiriéndose a padres, hijas e hijos de familia, para que desde otros espacios de educación se puedan abordar las necesidades primordiales de la población de mujeres y niñas. Se trata no únicamente de mejorar la calidad de vida de las mismas, sino también de crear espacios de inclusión que vayan encaminados en el pleno goce de sus derechos en todos sus espacios de desenvolvimiento de la sociedad

Reliability ofwood utility poles under stochastic wind load and material considering knots

Wood utility poles are simple structures used in power networks and their failure may produce a significant impact on their reliability as well as economic consequences. Wind loads are one of the main causes of damage in wood utility poles. The present study addresses the dynamic behavior of Argentinean Eucalyptus grandis wood poles with uncertain material properties under stochastic wind load. Regarding the material, the lengthwise variability of the Modulus of Elasticity (MOE) and the second moment of area are simulated through the Weak Zone (WZ) model taking into account the knots presence. The stochastic wind velocity field is derived using the Spectral Representation Method (SRM) considering temporal and spatial correlation. Then, the wind load is obtained under the considerations of the Argentinean standard CIRSOC 102. The governing equations are discretized through the Finite Element Method (FEM). The stochastic analysis is performed by means of Monte Carlo Simulations (MCS). In this study, displacements are evaluated such that a percentage of damage is found for each wind velocity. Fragility curves are a useful means to evaluate the failure probability of the poles for a defined failure mode, under a given range of demand, here the wind load. The WZ model results are compared with other MOE models previously developed (as a random variable and as a random field through the Non Gaussian Karhunen-Loève Expansion). Also, confidence bands of the fragility curves are obtained for 95% of confidence.Publicado en: Mecánica Computacional vol. XXXV, no. 21Facultad de Ingenierí

Reliability ofwood utility poles under stochastic wind load and material considering knots

Wood utility poles are simple structures used in power networks and their failure may produce a significant impact on their reliability as well as economic consequences. Wind loads are one of the main causes of damage in wood utility poles. The present study addresses the dynamic behavior of Argentinean Eucalyptus grandis wood poles with uncertain material properties under stochastic wind load. Regarding the material, the lengthwise variability of the Modulus of Elasticity (MOE) and the second moment of area are simulated through the Weak Zone (WZ) model taking into account the knots presence. The stochastic wind velocity field is derived using the Spectral Representation Method (SRM) considering temporal and spatial correlation. Then, the wind load is obtained under the considerations of the Argentinean standard CIRSOC 102. The governing equations are discretized through the Finite Element Method (FEM). The stochastic analysis is performed by means of Monte Carlo Simulations (MCS). In this study, displacements are evaluated such that a percentage of damage is found for each wind velocity. Fragility curves are a useful means to evaluate the failure probability of the poles for a defined failure mode, under a given range of demand, here the wind load. The WZ model results are compared with other MOE models previously developed (as a random variable and as a random field through the Non Gaussian Karhunen-Loève Expansion). Also, confidence bands of the fragility curves are obtained for 95% of confidence.Publicado en: Mecánica Computacional vol. XXXV, no. 21Facultad de Ingenierí

Impact of sperm DNA damage and oocyte-repairing capacity on trout development

Palabras clave extraídas del título[EN] Zygotic repair of paternal DNA is essential during embryo development. In spite of the interest devoted to sperm DNA damage, its combined effect with defect-repairing oocytes has not been analyzed. Modification of the breeding season is a common practice in aquaculture. This practice reduces developmental success and could affect the both factors: sperm DNA integrity and oocyte repair capacity. To evaluate the maternal role, we analyzed the progeny outcome after fertilizing in-season trout oocytes with untreated and with UV-irradiated sperm. We also analyzed the offspring obtained out of season with untreated sperm. The analysis of the number of lesions in 4 sperm nuclear genes revealed an increase of 1.22–11.18 lesions/10 kb in out-of-season sperm, similar to that obtained after sperm UV irradiation (400 µW/cm25 min). Gene expression showed in out-of-season oocytes the overexpression of repair genes (ogg1, ung, lig3, rad1) and downregulation of tp53, indicating an enhanced repairing activity and reduced capacity to arrest development upon damage. The analysis of the progeny in out-of-season embryos revealed a similar profile tolerant to DNA damage, leading to a much lower apoptotic activity at organogenesis, lower hatching rates and increased rate of malformations. The effects were milder in descendants from in-season-irradiated sperm, showing an enhanced repairing activity at epibolia. Results point out the importance of the repairing machinery provided by the oocyte and show how susceptible it is to environmental changes. Transcripts related to DNA damage signalization and repair could be used as markers of oocyte qualitySIThis work was supported by the Spanish Ministry of Economy and Competitiveness (project AGL2011-27787

Tolerance to paternal genotoxic damage promotes survival during embryo development in zebrafish (Danio rerio)

[EN] Spermatozoa carry DNA damage that must be repaired by the oocyte machinery upon fertilization. Different strategies could be adopted by different vertebrates to face the paternal genotoxic damage. Mammals have strong sperm selection mechanisms and activate a zygotic DNA damage response (DDR) (including cell cycle arrest, DNA repair and alternative apoptosis) in order to guarantee the genomic conformity of the reduced progeny. However, external fertilizers, with different reproductive strategies, seem to proceed distinctively. Previous results from our group showed a downregulation of apoptotic activity in trout embryos with a defective DNA repairing ability, suggesting that mechanisms of tolerance to damaged DNA could be activated in fish to maintain cell survival and to progress with development. In this work, zebrafish embryos were obtained from control or UV-irradiated sperm (carrying more than 10% of fragmented DNA but still preserving fertilization ability). DNA repair (γH2AX and 53BP1 foci), apoptotic activity, expression of genes related to DDR and malformation rates were analyzed throughout development. Results showed in the progeny from damaged sperm, an enhanced repairing activity at the mid-blastula transition stage that returned to its basal level at later stages, rendering at hatching a very high rate of multimalformed larvae. The study of transcriptional and post-translational activity of tp53 (ZDF-GENE-990415-270) revealed the activation of an intense DDR in those progenies. However, the downstream pro-apoptotic factor noxa (ZDF-GENE-070119-3) showed a significant downregulation, whereas the anti-apoptotic gene bcl2 (ZDF-GENE-051015-1) was upregulated, triggering a repressive apoptotic scenario in spite of a clear genomic instability. This repression can be explained by the observed upregulation of p53 isoform Δ113p53, which is known to enhance bcl2 transcription. Our results showed that tp53 is involved in DNA damage tolerance (DDT) pathways, allowing the embryo survival regardless of the paternal DNA damage. DDT could be an evolutionary mechanism in fish: tolerance to unrepaired sperm DNA could introduce new mutations, some of them potentially advantageous to face a changing environmentSIThis work was supported by Ministerio de Economı́a y Competitividad (AGL2011- 27787 and AGL2014-53167

Distribution of DNA damage in the sperm nucleus: A study of zebrafish as a model of histone-packaged chromatin

[EN] Reproductive defects can occur when the integrity of the male gamete genome is affected. Sperm chromatin is not homogeneous, having relaxed regions which are more accessible to the transcription machinery in the embryo, and thought to be specially sensitive to DNA damage. The level of damage in specific genes located in these sensitive regions could represent an early biomarker of damage. Our objective is to test the hypothesis that these more relaxed regions show greater susceptibility to damage in zebrafish, a species lacking protamines and whose sperm chromatin is compacted with histones. After sperm UV irradiation, treatment with H2O2 and cryopreservation, global chromatin fragmentation was evaluated using the TUNEL assay, and the number of lesions per 10 Kb in specific genes (hoxa3a, hoxb5b, sox2, accessible for early transcription and rDNA 18S and rDNA 28S) was quantified by using a qPCR approach. Additionally, oxidative damage within the sperm nucleus and the potential colocalization of this injury with histone H3 and TOPO IIα+β were located by using immunofluorescence. UV irradiation produced the highest degree of fragmentation (p = 0.041) and the highest number of lesions per 10 Kb in all the genes, but no differences were observed in sensitivity to damage in the studied genes (ranging from 14.93 to 8.03 lesions per 10 Kb in hoxb5b and 28S, respectively). In contrast, H2O2 and cryopreservation caused varying levels of damage in the analyzed genes which was not related to their accessibility, ranging from 0.00 to 1.65 lesions per 10 Kb in 28S and hoxb5b, respectively, after H2O2 treatment, and from 0.073 to 5.51 in 28S and sox2, respectively, after cryopreservation. Immunodetection near oxidative lesions also revealed different spatial patterns depending on the treatments used, these being mostly homogeneous with UV irradiation or cryopreservation, and peripherally located around the nucleus after H2O2 treatment. Oxidative lesions did not colocalize with histone H3 or TOPO IIα+β thus demonstrating that the relaxed DNA regions associated with these proteins were not more vulnerable to oxidative damage. Results suggest that accessibility of each agent to the nucleus could be the main factor responsible for the distribution of sperm DNA damage rather than the organization of the chromatin. Lesions in these genes important to early embryo development assayed in this study cannot be used as biomarkers of global DNA damageSISpanish Ministry of Economy and Competitiveness (project AGL2011-27787; AGL2014-53167-C3-3-R), Junta de Castilla y León (Spain) (EDU/1083/2013) and the Fondo Social Europe

Genetic and epigenetic alterations induced by bisphenol A exposure during different periods of spermatogenesis: from spermatozoa to the progeny

Exposure to bisphenol A (BPA) has been related to male reproductive disorders. Since this endocrine disruptor also displays genotoxic and epigenotoxic effects, it likely alters the spermatogenesis, a process in which both hormones and chromatin remodeling play crucial roles. The hypothesis of this work is that BPA impairs early embryo development by modifying the spermatic genetic and epigenetic information. Zebrafish males were exposed to 100 and 2000 μg/L BPA during early spermatogenesis and during the whole process. Genotoxic and epigenotoxic effects on spermatozoa (comet assay and immunocytochemistry) as well as progeny development (mortality, DNA repairing activity, apoptosis and epigenetic profile) were evaluated. Exposure to 100 µg/L BPA during mitosis slightly increased sperm chromatin fragmentation, enhancing DNA repairing activity in embryos. The rest of treatments promoted high levels of sperm DNA damage, triggering apoptosis in early embryo and severely impairing survival. Regarding epigenetics, histone acetylation (H3K9Ac and H3K27Ac) was similarly enhanced in spermatozoa and embryos from males exposed to all the treatments. Therefore, BPA male exposure jeopardizes embryonic survival and development due to the transmission of a paternal damaged genome and of a hyper-acetylated histone profile, both alterations depending on the dose of the toxicant and the temporal window of exposureS

Male exposure to bisphenol a impairs spermatogenesis and triggers histone hyperacetylation in zebrafish testes

[EN] Bisphenol A (BPA) is an endocrine disruptor whose ubiquitous presence in the environment has been related with impairment of male reproduction. BPA can cause both transcriptomic and epigenetic changes during spermatogenesis. To evaluate the potential effects of male exposure to BPA, adult zebrafish males were exposed during spermatogenesis to doses of 100 and 2000 μg/L, which were reported in contaminated water bodies and higher than those allowed for human consumption. Fertilization capacity and survival at hatching were analysed after mating with untreated females. Spermatogenic progress was analysed through a morphometrical study of testes and apoptosis was evaluated by TUNEL assay. Testicular gene expression was evaluated by RT-qPCR and epigenetics by using ELISA and immunocytochemistry. In vitro studies were performed to investigate the role of Gper. Chromatin fragmentation and the presence of transcripts were also evaluated in ejaculated sperm. Results on testes from males treated with the highest dose showed a significant decrease in spermatocytes, an increase in apoptosis, a downregulation of ccnb1 and sycp3, all of which point to an alteration of spermatogenesis and to meiotic arrest and an upregulation of gper1 and esrrga receptors. Additionally, BPA at 2000 μg/L caused missregulation of epigenetic remodelling enzymes transcripts in testes and promoted DNA hypermethylation and H3K27me3 demethylation. BPA also triggered an increase in histone acetyltransferase activity, which led to hyperacetylation of histones (H3K9ac, H3K14ac, H4K12ac). In vitro reversion of histone acetylation changes using a specific GPER antagonist, G-36, suggested this receptor as mediator of histone hyperacetylation. Males treated with the lower dose only showed an increase in some histone acetylation marks (H3K14ac, H4K12ac) but their progeny displayed very limited survival at hatching, revealing the deleterious effects of unbalanced paternal epigenetic information. Furthermore, the highest dose of BPA led to chromatin fragmentation, promoting direct reproductive effects, which are incompatible with embryo developmentSIThis work was supported by the Spanish Ministry of Economy and Competitiveness (project AGL2014-53167-C3-3-R), Junta de Castilla y León (Spain) (EDU/1083/2013), the Fondo Social Europeo and by an EMBO Short-Term Fellowship to SG

Cardiogenesis impairment promoted by bisphenol A exposure is successfully counteracted by epigallocatechin gallate

[EN] Exposure to the emerging contaminant bisphenol A (BPA) is ubiquitous and associated with cardiovascular disorders. BPA effect as endocrine disruptor is widely known but other mechanisms underlying heart disease, such as epigenetic modifications, remain still unclear. A compound of green tea, epigallocatechin gallate (EGCG), may act both as anti-estrogen and as inhibitor of some epigenetic enzymes. The aims of this study were to analyze the molecular processes related to BPA impairment of heart development and to prove the potential ability of EGCG to neutralize the toxic effects caused by BPA on cardiac health. Zebrafish embryos were exposed to 2000 and 4000 μg/L BPA and treated with 50 and 100 μM EGCG. Heart malformations were assessed at histological level and by confocal imaging. Expression of genes involved in cardiac development, estrogen receptors and epigenetic enzymes was analyzed by qPCR whereas epigenetic modifications were evaluated by whole mount immunostaining. BPA embryonic exposure led to changes in cardiac phenotype, induced an overexpression of hand2, a crucial factor for cardiomyocyte differentiation, increased the expression of estrogen receptor (esr2b), promoted an overexpression of a histone acetyltransferase (kat6a) and also caused an increase in histone acetylation, both mechanisms being able to act in sinergy. EGCG treatment neutralized all the molecular alterations caused by BPA, allowing the embryos to go on with a proper heart development. Both molecular mechanisms of BPA action (estrogenic and epigenetic) likely lying behind cardiogenesis impairment were successfully counteracted by EGCG treatmentSIThis work was funded by the Spanish Ministry of Economy and Competitiveness (Project AGL2014-53167-C3-3-R; PhD Grant BES-2015-071885)