72 research outputs found

    Modelación hidrodinámica y morfológica del Río La Estrella, Limón

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    Proyecto de Investigación (Código: 5402-1421-3101, Centro funcional: 1421006) Instituto Tecnológico de Costa Rica. Vicerrectoría de Investigación y Extensión (VIE). Escuela de Ingeniería Agrícola, 2017La Vertiente Atlántica es una zona altamente vulnerable a inundaciones donde, a causa de su topografía y cambios en el uso de la tierra, se ha debilitado la capacidad de retención de agua en las cuencas y en consecuencia se ha aumentado la capacidad destructiva de las descargas extremas en los ríos. Un fenómeno que ha marcado el antes y el después en la evolución geológica y morfológica de las cuencas en esta zona es el terremoto de Limón en el año 1991, el cual llegó a modificar la dinámica tradicional y estabilidad de sus cauces. Dentro de las principales cuencas afectadas se encuentra la del Río La Estrella, principalmente en la parte baja, donde se localiza el Valle de la Estrella. En esta zona, se ha observado un aumento en la frecuencia y magnitud de los desbordamientos, una constante acumulación de sedimentos provenientes de las partes más altas y una inestabilidad en la dinámica del cauce. Esto ha aumentado la vulnerabilidad, ante los impactos por inundación y arrastre de sedimentos, tanto de sus habitantes, actividades productivas y ecosistemas que interactúan en esta área. En este proyecto se hace una evaluación de la hidrodinámica y transporte de sedimentos en la parte baja del río La Estrella (desde el Valle de la Estrella hasta la desembocadura) por medio de los modelos matemáticos HEC-RAS e IBER en una y dos dimensiones, logrando un mejor entendimiento del comportamiento del río, identificando condiciones y puntos críticos de flujo y transporte de sedimentos, y simulando posibles situaciones ante escenarios basados en ocurrencia de eventos extremos útiles para una adecuada gestión de la cuenca.The Atlantic coast is highly vulnerable to flooding due to its topography and changes in land use. This situation has weakened the water retention capacity of its watersheds increasing the destructive capacity of the flood events. The Limón Earthquake in 1991 was the phenomenon that marked a before and after, in terms of geological and morphological evolution of the basins in this area, modifying the traditional dynamics and stability of many river channels. One of the main affected watersheds is the lower part of La Estrella River, where La Estrella Valley is located. This area has faced an increase in the frequency and magnitude of the river overflow, a constant accumulation of sediments coming from the higher parts and an instability in the channel dynamics. This has increased the vulnerability of its inhabitants, productive activities and ecosystems that interact in this area. This project models the hydrodynamics and sediment transport in the lower part of La Estrella River (from the Valley to the river mouth) by means of the mathematical models HEC-RAS and IBER in one and two dimensions. It was able to obtain a better understanding of the river behavior, by identifying conditions and critical floe and sediment points. Different flow scenarios where also able to simulated based on the occurrence of extreme events useful for a proper basin management

    Protease-activated receptor 2 activation induces behavioural changes associated with depression-like behaviour through microglial-independent modulation of inflammatory cytokines

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    Rationale: Major depressive disorder (MDD) is a leading cause of disability worldwide but currently prescribed treatments do not adequately ameliorate the disorder in a significant portion of patients. Hence, a better appreciation of its aetiology may lead to the development of novel therapies. Objectives: In the present study, we have built on our previous findings indicating a role for protease-activated receptor-2 (PAR2) in sickness behaviour to determine whether the PAR2 activator, AC264613, induces behavioural changes similar to those observed in depression-like behaviour. Methods: AC264613-induced behavioural changes were examined using the open field test (OFT), sucrose preference test (SPT), elevated plus maze (EPM), and novel object recognition test (NOR). Whole-cell patch clamping was used to investigate the effects of PAR2 activation in the lateral habenula with peripheral and central cytokine levels determined using ELISA and quantitative PCR. Results: Using a blood–brain barrier (BBB) permeable PAR2 activator, we reveal that AC-264613 (AC) injection leads to reduced locomotor activity and sucrose preference in mice but is without effect in anxiety and memory-related tasks. In addition, we show that AC injection leads to elevated blood sera IL-6 levels and altered cytokine mRNA expression within the brain. However, neither microglia nor peripheral lymphocytes are the source of these altered cytokine profiles. Conclusions: These data reveal that PAR2 activation results in behavioural changes often associated with depression-like behaviour and an inflammatory profile that resembles that seen in patients with MDD and therefore PAR2 may be a target for novel antidepressant therapies

    Phylogeographical analysis of the dominant multidrug-resistant H58 clade of Salmonella Typhi identifies inter- and intracontinental transmission events.

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    The emergence of multidrug-resistant (MDR) typhoid is a major global health threat affecting many countries where the disease is endemic. Here whole-genome sequence analysis of 1,832 Salmonella enterica serovar Typhi (S. Typhi) identifies a single dominant MDR lineage, H58, that has emerged and spread throughout Asia and Africa over the last 30 years. Our analysis identifies numerous transmissions of H58, including multiple transfers from Asia to Africa and an ongoing, unrecognized MDR epidemic within Africa itself. Notably, our analysis indicates that H58 lineages are displacing antibiotic-sensitive isolates, transforming the global population structure of this pathogen. H58 isolates can harbor a complex MDR element residing either on transmissible IncHI1 plasmids or within multiple chromosomal integration sites. We also identify new mutations that define the H58 lineage. This phylogeographical analysis provides a framework to facilitate global management of MDR typhoid and is applicable to similar MDR lineages emerging in other bacterial species

    How culturally unique are pandemic effects? Evaluating cultural similarities and differences in effects of age, biological sex, and political beliefs on COVID impacts

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    Despite being bio-epidemiological phenomena, the causes and effects of pandemics are culturally influenced in ways that go beyond national boundaries. However, they are often studied in isolated pockets, and this fact makes it difficult to parse the unique influence of specific cultural psychologies. To help fill in this gap, the present study applies existing cultural theories via linear mixed modeling to test the influence of unique cultural factors in a multi-national sample (that moves beyond Western nations) on the effects of age, biological sex, and political beliefs on pandemic outcomes that include adverse financial impacts, adverse resource impacts, adverse psychological impacts, and the health impacts of COVID. Our study spanned 19 nations (participant N = 14,133) and involved translations into 9 languages. Linear mixed models revealed similarities across cultures, with both young persons and women reporting worse outcomes from COVID across the multi-national sample. However, these effects were generally qualified by culture-specific variance, and overall more evidence emerged for effects unique to each culture than effects similar across cultures. Follow-up analyses suggested this cultural variability was consistent with models of pre-existing inequalities and socioecological stressors exacerbating the effects of the pandemic. Collectively, this evidence highlights the importance of developing culturally flexible models for understanding the cross-cultural nature of pandemic psychology beyond typical WEIRD approaches

    An extended genotyping framework for Salmonella enterica serovar Typhi, the cause of human typhoid.

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    The population of Salmonella enterica serovar Typhi (S. Typhi), the causative agent of typhoid fever, exhibits limited DNA sequence variation, which complicates efforts to rationally discriminate individual isolates. Here we utilize data from whole-genome sequences (WGS) of nearly 2,000 isolates sourced from over 60 countries to generate a robust genotyping scheme that is phylogenetically informative and compatible with a range of assays. These data show that, with the exception of the rapidly disseminating H58 subclade (now designated genotype 4.3.1), the global S. Typhi population is highly structured and includes dozens of subclades that display geographical restriction. The genotyping approach presented here can be used to interrogate local S. Typhi populations and help identify recent introductions of S. Typhi into new or previously endemic locations, providing information on their likely geographical source. This approach can be used to classify clinical isolates and provides a universal framework for further experimental investigations

    Meta-analyses of genome-wide association studies for postpartum depression

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    Objective: Postpartum depression (PPD) is a common subtype of major depressive disorder (MDD) that is more heritable, yet is understudied in psychiatric genetics. The authors conducted meta-analyses of genome-wide association studies (GWASs) to investigate the genetic architecture of PPD. Method: Meta-analyses were conducted on 18 cohorts of European ancestry (17,339 PPD cases and 53,426 controls), one cohort of East Asian ancestry (975 cases and 3,780 controls), and one cohort of African ancestry (456 cases and 1,255 controls), totaling 18,770 PPD cases and 58,461 controls. Post-GWAS analyses included 1) single-nucleotide polymorphism (SNP)–based heritability (), 2) genetic correlations between PPD and other phenotypes, and 3) enrichment of the PPD GWAS findings in 27 human tissues and 265 cell types from the mouse central and peripheral nervous system. Results: No SNP achieved genome-wide significance in the European or the trans-ancestry meta-analyses. The of PPD was 0.14 (SE=0.02). Significant genetic correlations were estimated for PPD with MDD, bipolar disorder, anxiety disorders, posttraumatic stress disorder, insomnia, age at menarche, and polycystic ovary syndrome. Cell-type enrichment analyses implicate inhibitory neurons in the thalamus and cholinergic neurons within septal nuclei of the hypothalamus, a pattern that differs from MDD. Conclusions: While more samples are needed to reach genome-wide levels of significance, the results presented confirm PPD as a polygenic and heritable phenotype. There is also evidence that despite a high correlation with MDD, PPD may have unique genetic components. Cell enrichment results suggest GABAergic neurons, which converge on a common mechanism with the only medication approved by the U.S. Food and Drug Administration for PPD (brexanolone)
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