59 research outputs found

    The large carpenter bee Xylocopa augusti (Hymenoptera: Apidae): new record for Chile

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    The large carpenter bee Xylocopa (Neoxylocopa) augusti Lepeletier de Saint Fargeau, 1841, is here recorded for the first time in Chile. This new record increases to four the number of carpenter bees known for the country. Host plant associations for X. augusti in Chile are provided. A key to the species of Xylocopa Latreille in Chile as well as comments on the presence of X. (N.) bruesi Cockerell in the country are also presented.Fil: Montalva, José.Fil: Allendes, Juan L..Fil: Lucia, Mariano. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Entomología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Fertility dynamics and life history tactics vary by socioeconomic position in a transitioning cohort of postreproductive Chilean women

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    Globally, mortality and fertility rates generally fall as resource abundance increases. This pattern represents an evolutionary paradox insofar as resource-rich ecological contexts can support higher numbers of offspring, a component of biological fitness. This paradox has not been resolved, in part because the relationships between fertility, life history strategies, reproductive behavior, and socioeconomic conditions are complex and cultural-historically contingent. We aim to understand how we might make sense of this paradox in the specific context of late-twentieth-century, mid–demographic transition Chile. We use distribution-specific generalized linear models to analyze associations between fertility-related life-history traits—number of offspring, ages at first and last reproduction, average interbirth interval, and average number of live births per reproductive span year—and socioeconomic position (SEP) using data from a cohort of 6,802 Chilean women born between 1961 and 1970. We show that Chilean women of higher SEP have shorter average interbirth intervals, more births per reproductive span year, later age at first reproduction, earlier ages at last reproduction, and, ultimately, fewer children than women of lower SEP. Chilean women of higher SEP consolidate childbearing over a relatively short time span in the middle of their reproductive careers, whereas women of lower SEP tend to reproduce over the entirety of their reproductive lifespans. These patterns may indicate that different SEP groups follow different pathways toward declining fertility during the demographic transition, reflecting different life-history trade-offs in the process

    Ultimate capacity of rectangular concrete-filled steel tubular columns under unequal load eccentricities

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    The paper describes 36 experimental tests conducted on rectangular and square tubular columns filled with normal and high strength concrete and subjected to a non-constant bending moment distribution with respect to the weak axis. The test parameters were the nominal strength of concrete (30 and 90 MPa), the cross-section aspect ratio (square or rectangular), the thickness (4 or 5 mm) and the ratio of the top and bottom first order eccentricities e top/e bottom (1, 0.5, 0 and - 0.5). The ultimate load of each test was compared with the design loads from Eurocode 4, presenting unsafe results inside a 10% safety margin. The tests show that the use of high strength concrete is more useful for the cases of non-constant bending moment, whereas if the aim is to obtain a more ductile behavior the use of concrete-filled columns is more appealing in the cases of normal strength concrete with non-constant bending moments because, although they resist less axial force than the members with HSC, they obtain a softened post-peak behavior. © 2011 Elsevier Ltd.The authors wish to express their sincere gratitude to the Spanish Ministry of Education for the help provided through projects BIA2005_255 and BIA2009_9411, and to the European Community for FEDER funds.Hernández Figueirido, D.; Romero, ML.; Bonet Senach, JL.; Montalva Subirats, JM. (2012). Ultimate capacity of rectangular concrete-filled steel tubular columns under unequal load eccentricities. Journal of Constructional Steel Research. 68(1):107-117. https://doi.org/10.1016/j.jcsr.2011.07.014S10711768

    Optimal design of prestressed concrete hollow core slabs taking into account its fire resistance

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    [EN] Prestressed hollow core slabs are a concrete element widely used as construction floor product, which manufacturing process has greatly been improved in recent years. Several research studies focused on hollow core slab performance, mainly related to its fire behavior, have provided new limit states to be assessed throughout its life cycle. Therefore, the hollow core slab design needs to be reviewed to allow for these improvements, a process which may involve changes to its geometry. In order to deal with this review, modern computational optimization techniques offer an alternative approach to traditional structural product design procedure, mainly based on the engineer's prior experience. This paper proposes a hollow core slab model (including variables and constraints) to develop heuristic search algorithms, such as simulated annealing, in order to find the most economical slab design including the fire resistant constraint and taking into account all available manufacturing technologies. The optimal designs obtained by this process save up to 20% in cross-section area compared with common circular void designs from market, which is taken as a comparison pattern. The results show that traditional designs are deficient when the fire resistant constraint is considered, so that precast manufacturers and machinery designers should use optimization techniques to modify their hollow core slab geometry.Albero Gabarda, V.; Saura Arnau, H.; Hospitaler Pérez, A.; Montalva Subirats, JM.; Romero, ML. (2018). Optimal design of prestressed concrete hollow core slabs taking into account its fire resistance. Advances in Engineering Software. 122:81-92. doi:10.1016/j.advengsoft.2018.05.001S819212

    EVALUACIÓN DE LA VIRULENCIA DE HONGOS ENTOMOPATÓGENOS DEL PULGÓN DEL CIPRÉS, DE DOS REGIONES ECOLÓGICAS DE CHILE. II

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    El pulgón del ciprés Cinara cupressi, se considera uno de los insectos invasores más dañinos del mundo, ha provocado una gran mortalidad en especies Cupresáceas nativas y exóticas en varios países. En Chile, fue detectado el año 2003 y para el año 2008 esta plaga ya se encontraba distribuida en todo el país, afectando especies cupresáceas forestales exóticas como Cupressus macrocarpa y especies nativas, tales como, Austrocedrus chilensis (Ciprés de la Cordillera) y Fitzroya cupressoides (Alerce), que están categorizadas en el estado de conservación vulnerable y en peligro respectivamente. El área forestal de Chile ha potenciado y privilegiado el uso de controladores biológicos como parte del manejo integrado de plagas. Es por esto que se ha utilizado el parasitoide Pauesia juniperorum. Sin embargo, se han detectado bajos niveles de parasitismo. Se propone el uso de hongos entomopatógenos como alternativa y complemento al control biológico. Se prospectaron hongos entomopatógenos en la Región ecológica mediterránea per-húmeda y en la Región oceánica con influencia mediterránea. Como resultado se han identificado seis géneros de hongos descritos como patógenos de insectos. Sin embargo, bajo condiciones de laboratorio sólo cepas del género Verticillium fueron virulentas, causando sobre el 80% de mortalidad acumulada a los 7 días. No hubo diferencias significativas entre las cepas de Verticillium y un producto químico (pirimicarb) aplicado como control, aunque el hongo fue más lento. Las cepas más virulentas fueron identificadas como Verticillium lecanii, Ve 1 y Ve 2, con un TL50 de: 3.2 y 3.1 días y un DL50: 1.24 y 1.37 conidias mL-1 respectivamente, sugiriendo el uso de estos hongos para controlar C. cupressi en Chile

    PROSPECCIÓN DE HONGOS ENTOMOPATÓGENOS DEL PULGÓN DEL CIPRÉS EN DOS REGIONES ECOLÓGICAS DE CHILE. I

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    El pulgón del ciprés (Cinara cupressi), es una plaga exótica distribuida en todo el territorio continental chileno que ha provocado daños importantes tanto en especies forestales introducidas como nativas. Se han estudiado algunos aspectos de la biología de este pulgón, mediante control biológico y productos químicos, los cuales no presentan actualmente resultados satisfactorios. Durante el tiempo que esta plaga se ha establecido en Chile, no se ha realizado un estudio sistemático de hongos entomopatógenos asociados a este pulgón, aunque se cuenta con antecedentes de un control promisorio en pulgones con estos agentes en otros países. Con el objetivo inicial de aislar en una primera fase del presente estudio hongos patogénicos potenciales para el control biológico de C. cupressi, iniciamos su búsqueda en dos regiones ecológicas del sur de Chile (Región ecológica Mediterránea PerHúmeda y Región ecológica Oceánica con influencia Mediterránea), seleccionándose en cada una de ellas 6 sitios de muestreo donde en cada uno se recolectaron 10 ramas con colonias de pulgones que fueron mantenidas en una cámara bioclimática (20 ± 2 °C, 16:8 h) por 7 días,  para estimular el desarrollo fúngico. Se aislaron integrantes de lo géneros Verticillium, Paecilomyces (ambos con mayor frecuencia de presencia), Fusarium y un entomophthoral en estudio

    Fetal lung underdevelopment is rescued by administration of amniotic fluid stem cell extracellular vesicles in rodents

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    Fetal lung underdevelopment, also known as pulmonary hypoplasia, is characterized by decreased lung growth and maturation. The most common birth defect found in babies with pulmonary hypoplasia is congenital diaphragmatic hernia (CDH). Despite research and clinical advances, babies with CDH still have high morbidity and mortality rates, which are directly related to the severity of lung underdevelopment. To date, there is no effective treatment that promotes fetal lung growth and maturation. Here, we describe a stem cell–based approach in rodents that enhances fetal lung development via the administration of extracellular vesicles (EVs) derived from amniotic fluid stem cells (AFSCs). Using fetal rodent models of pulmonary hypoplasia (primary epithelial cells, organoids, explants, and in vivo), we demonstrated that AFSC-EV administration promoted branching morphogenesis and alveolarization, rescued tissue homeostasis, and stimulated epithelial cell and fibroblast differentiation. We confirmed this regenerative ability in in vitro models of lung injury using human material, where human AFSC-EVs obtained following good manufacturing practices restored pulmonary epithelial homeostasis. Investigating EV mechanism of action, we found that AFSC-EV beneficial effects were exerted via the release of RNA cargo. MicroRNAs regulating the expression of genes involved in lung development, such as the miR17–92 cluster and its paralogs, were highly enriched in AFSC-EVs and were increased in AFSC-EV–treated primary lung epithelial cells compared to untreated cells. Our findings suggest that AFSC-EVs hold regenerative ability for underdeveloped fetal lungs, demonstrating potential for therapeutic application in patients with pulmonary hypoplasia

    Efficacy and safety assessment of different dosage of benznidazol for the treatment of Chagas disease in chronic phase in adults (MULTIBENZ study): Study protocol for a multicenter randomized Phase II non-inferiority clinical trial

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    Background: Chagas disease (CD) continues to be a neglected infectious disease with one of the largest burdens globally. Despite the modest cure rates in adult chronic patients and its safety profile, benznidazole (BNZ) is still the drug of choice. Its current recommended dose is based on nonrandomized studies, and efficacy and safety of the optimal dose of BNZ have been scarcely analyzed in clinical trials.Methods/design: MULTIBENZ is a phase II, randomized, noninferiority, double-blind, multicenter international clinical trial. A total of 240 patients with Trypanosoma CD in the chronic phase will be recruited in four different countries (Argentina, Brazil, Colombia, and Spain). Patients will be randomized to receive BNZ 150 mg/day for 60 days, 400 mg/day for 15 days, or 300 mg/day for 60 days (comparator arm). The primary outcome is the efficacy of three different BNZ therapeutic schemes in terms of dose and duration. Efficacy will be assessed according to the proportion of patients with sustained parasitic load suppression in peripheral blood measured by polymerase chain reaction. The secondary outcomes are related to pharmacokinetics and drug tolerability. The follow-up will be 12 months from randomization to end of study participation. Recruitment was started in April 2018.Conclusion: This is a clinical trial conducted for the assessment of different dose schemes of BNZ compared with the standard treatment regimen for the treatment of CD in the chronic phase. MULTIBENZ may help to clarify which is the most adequate BNZ regimen in terms of efficacy and safety, predicated on sustained parasitic load suppression in peripheral blood.Fil: Molina Morant, D.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Fernández, M. L.. Dirección Nacional de Instituto de Investigación. Administración Nacional de Laboratorio e Instituto de Salud “Dr. C. G. Malbrán”. Instituto Nacional de Parasitología "Dr. Mario Fatala Chaben”; ArgentinaFil: Bosch Nicolau, P.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Sulleiro, E.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Bangher, M.. Instituto de Cardiologia de Corrientes Juana Francisca Cabral.; ArgentinaFil: Salvador, F.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Sanchez Montalva, A.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; EspañaFil: Ribeiro, A.L.P.. Universidade Federal de Minas Gerais; BrasilFil: De Paula, A.M.B.. Universidad Federal de Montes Claros; BrasilFil: Eloi, S.. Universidade Federal de Minas Gerais; BrasilFil: Oliveira Correa, Ronaldo. Fundación Oswaldo Cruz; BrasilFil: Villar, J. C.. Instituto de Cardiología; ColombiaFil: Sosa-Estani, Sergio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Centro de Investigaciones en Epidemiología y Salud Pública. Instituto de Efectividad Clínica y Sanitaria. Centro de Investigaciones en Epidemiología y Salud Pública; ArgentinaFil: Molina, I.. Universidad Autónoma de Barcelona. Hospital Vall D' Hebron; Españ

    Cell-Mediated Immune Responses to in vivo -Expressed and Stage-Specific Mycobacterium tuberculosis Antigens in Latent and Active Tuberculosis Across Different Age Groups

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    A quarter of the global human population is estimated to be latently infected by Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). TB remains the global leading cause of death by a single pathogen and ranks among the top-10 causes of overall global mortality. Current immunodiagnostic tests cannot discriminate between latent, active and past TB, nor predict progression of latent infection to active disease. The only registered TB vaccine, Bacillus Calmette-Guérin (BCG), does not adequately prevent pulmonary TB in adolescents and adults, thus permitting continued TB-transmission. Several Mtb proteins, mostly discovered through IFN-γ centered approaches, have been proposed as targets for new TB-diagnostic tests or -vaccines. Recently, however, we identified novel Mtb antigens capable of eliciting multiple cytokines, including antigens that did not induce IFN-γ but several other cytokines. These antigens had been selected based on high Mtb gene-expression in the lung in vivo, and have been termed in vivo expressed (IVE-TB) antigens. Here, we extend and validate our previous findings in an independent Southern European cohort, consisting of adults and adolescents with either LTBI or TB. Our results confirm that responses to IVE-TB antigens, and also DosR-regulon and Rpf stage-specific Mtb antigens are marked by multiple cytokines, including strong responses, such as for TNF-α, in the absence of detectable IFN-γ production. Except for TNF-α, the magnitude of those responses were significantly higher in LTBI subjects. Additional unbiased analyses of high dimensional flow-cytometry data revealed that TNF-α+ cells responding to Mtb antigens comprised 17 highly heterogeneous cell types. Among these 17 TNF-α+ cells clusters identified, those with CD8+TEMRA or CD8+CD4+ phenotypes, defined by the expression of multiple intracellular markers, were the most prominent in adult LTBI, while CD14+ TNF-α+ myeloid-like clusters were mostly abundant in adolescent LTBI. Our findings, although limited to a small cohort, stress the importance of assessing broader immune responses than IFN-γ alone in Mtb antigen discovery as well as the importance of screening individuals of different age groups. In addition, our results provide proof of concept showing how unbiased multidimensional multiparametric cell subset analysis can identify unanticipated blood cell subsets that could play a role in the immune response against Mtb

    World-wide distributions of lactase persistence alleles and the complex effects of recombination and selection

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    The genetic trait of lactase persistence (LP) is associated with at least five independent functional single nucleotide variants in a regulatory region about 14 kb upstream of the lactase gene [-13910*T (rs4988235), -13907*G (rs41525747), -13915*G (rs41380347), -14009*G (rs869051967) and -14010*C (rs145946881)]. These alleles have been inferred to have spread recently and present-day frequencies have been attributed to positive selection for the ability of adult humans to digest lactose without risk of symptoms of lactose intolerance. One of the inferential approaches used to estimate the level of past selection has been to determine the extent of haplotype homozygosity (EHH) of the sequence surrounding the SNP of interest. We report here new data on the frequencies of the known LP alleles in the 'Old World' and their haplotype lineages. We examine and confirm EHH of each of the LP alleles in relation to their distinct lineages, but also show marked EHH for one of the older haplotypes that does not carry any of the five LP alleles. The region of EHH of this (B) haplotype exactly coincides with a region of suppressed recombination that is detectable in families as well as in population data, and the results show how such suppression may have exaggerated haplotype-based measures of past selection
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