26 research outputs found

    Aplicación de un Modelo de Series de Tiempo para el pronóstico de la Tasa de Inflación del Perú

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    La presente investigación tuvo como objetivo estimar un modelo para la obtención de pronósticos confiables de la tasa de inflación para un horizonte a mediano plazo. La estabilidad de precios es condición necesaria para el desarrollo de las actividades económicas y constituye uno de los objetivos macroeconómicos fundamentales. Con información histórica de una serie mensual de la tasa de inflación, para el periodo enero 2013 a setiembre 2023, y la aplicación del método de Box y Jenkins, se estima un modelo SARIMA (1,1,1) (0,0,1) [12]. Los resultados permiten contar con información confiable y oportuna para la adecuada toma de decisiones por parte de los agentes económicos y los responsables de la política económica en nuestro país

    Machine learning workflows identify a microRNA signature of insulin transcription in human tissues

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    Dicer knockout mouse models demonstrated a key role for microRNAs in pancreatic β-cell function. Studies to identify specific microRNA(s) associated with human (pro-)endocrine gene expression are needed. We profiled microRNAs and key pancreatic genes in 353 human tissue samples. Machine learning workflows identified microRNAs associated with (pro-)insulin transcripts in a discovery set of islets (n = 30) and insulin-negative tissues (n = 62). This microRNA signature was validated in remaining 261 tissues that include nine islet samples from individuals with type 2 diabetes. Top eight microRNAs (miR-183-5p, -375-3p, 216b-5p, 183-3p, -7-5p, -217-5p, -7-2-3p, and -429-3p) were confirmed to be associated with and predictive of (pro-)insulin transcript levels. Use of doxycycline-inducible microRNA-overexpressing human pancreatic duct cell lines confirmed the regulatory roles of these microRNAs in (pro-)endocrine gene expression. Knockdown of these microRNAs in human islet cells reduced (pro-)insulin transcript abundance. Our data provide specific microRNAs to further study microRNA-mRNA interactions in regulating insulin transcription

    Density, but not shape, of hippocampal dendritic spines varies after a seizure-inducing acute dose of monosodium glutamate in rats

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    Dendritic spines are the main postsynaptic neuronal targets of excitatory inputs in cortical neurons, and both spine density and shape possess a well known adaptive synaptic-stimulation-dependent plastic capacity. Eighteen Sprague-Dawley adult male rats were used. Monosodium glutamate-treated rats (4 g/kg of body weight, i.p.) showed tonic and clonic epileptic seizures, as well as less dendritic spines in the apical arborization of their hippocampal CA1 pyramidal cells, compared to both control groups. No changes were seen in the proportional density of thin, stubby, mushroom-shaped, wide, or ramified spines between groups. Excessive glutamate-mediated excitatory activity on receptors could have led dendritic spines to shrink until they disappeared, while the spine-type proportion may be kept balanced as an adaptive response. © 2004 Elsevier Ireland Ltd. All rights reserved

    Difficolt\ue0 di comprensione del testo

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    L'articolo articola alcune tipologie di difficolt\ue0 di comprensione del testo molto diffuse ed illustra alcune metodologie di azione didattica nella scuola primaria e secondaria, riconducibili all'approcco per strategie e a quello per analisi del testo

    Análisis de la evapotranspiración y el índice modificado de fournier en el municipio de Ahuacatlán, Nayarit, México

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    There is a global concern to know the trends on climate variables to prevent natural disasters and adapt measures in diverse productive activities. The objective of this work was to analyze the effect that potential evapotranspiration (ETo) and modified Fournier index (MFi) have on soil erosion, in the municipality of Ahuacatlan Nayarit during the period 1980-2009. Climatological records of precipitation and maximum and minimum temperatures were taken from the official website of the National Meteorological Service; a data cleaning and data quality control was performed using RClimdex software; data processing and variable calculation was carried by the Moclic software. Regarding the ETo variable, no significant changes were observed annually but a considered increasing trend in the months of july and august. A significant trend towards an increase was observed annually for the MFi. It was found that july, august, june and september were the months that most affect such trend. An increase in the ETo and MFi variables was found during july, which can cause higher damage on the soil.A nivel mundial existe preocupación por conocer las tendencias de variables climáticas, para prevenir desastres naturales y efectuar medidas de adaptación en diversas actividades productivas. El objetivo de este trabajo es analizar el efecto que sobre la erosión del suelo tienen las variables; evapotranspiración potencial (ETo) y el índice modificado de Fournier (MFi), en el municipio de Ahuacatlán, Nayarit durante el periodo 1980-2009. Desde la página oficial del Servicio Meteorológico Nacional fueron tomados los registros climatológicos de precipitación y temperaturas máxima y mínima, se realizó una depuración y control de calidad de los datos mediante el software RClimdex, el procesamiento de datos y cálculo de variables se llevó a cabo mediante el software Moclic. Respecto a la variable ETo, en forma anual no se observaron cambios significativos, pero sí una considerada tendencia al incremento en los meses de julio y agosto. Para el MFi, en forma anual se observó una tendencia significativa hacia el incremento, se encontró que los meses que más inciden en la mencionada tendencia son julio, agosto, junio y septiembre. En el mes de julio se presentó un incremento de las variables ETo y MFi lo que puede ocasionar mayor daño del suelo

    Neonatal exposure to monosodium glutamate disrupts place learning ability in adult rats

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    The activation of glutamatergic NMDA receptors of the hippocampus is closely associated with expression of place learning. Neonatal exposure to monosodium glutamate leads to abnormal expression of NMDA receptor subunits in the hippocampus, but its effect on place learning is unknown. Place learning acquisition and retrieval were assessed in mature adult rats after subcutaneous injection of monosodium glutamate (4 mg/g body weight) in eight neonatal rat pups at postnatal days one, three, five, and seven. Eight untreated rats were used as controls. At four months of age, the rats were challenged over a period of nine days with a place learning task. The task used an acquisition-retrieval paradigm in a Morris maze. Place learning acquisition was impaired in the experimental rats, which were unable to reduce their escape latencies during the nine training days. Controls improved between the fifth and ninth days of training. Test trials showed that retrieval of spatial information was also impaired in the experimental animals. These results show that both place learning acquisition and retrieval abilities in mature rats are impaired by neonatal treatment with monosodium glutamate. These findings may be related to the abnormal expression of NMDA receptor subunits in the hippocampus. © 2005 Elsevier Inc. All rights reserved

    Excitotoxic neonatal damage induced by monosodium glutamate reduces several GABAergic markers in the cerebral cortex and hippocampus in adulthood

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    Monosodium glutamate (MSG) administered to neonatal rats during the first week of life induces a neurodegenerative process, which is represented by several neurochemical alterations of surviving neurons in the brain, where signalling mediated by GABA is essential for excitation threshold maintenance. GABA-positive cells, [3H]-GABA uptake, expression of mRNA for GABA transporters GAT-1 and GAT-3, and expression of mRNA and protein for two main GABA synthesizing enzymes, GAD65 and GAD67, were measured at postnatal day 60, after MSG neonatal treatment in two critical cerebral regions, cerebral cortex and hippocampus. GABA-positive cells, [3H]-GABA uptake, and mRNA for GAT-1, were significantly diminished in both cerebral regions. In the cerebral cortex, MSG neonatal treatment also decreased the mRNA for GAD67 and protein for GAD65 without significant changes in its corresponding protein and mRNA, respectively. Moreover in the hippocampus, mRNA and protein for GAD65 were increased, whilst GAD67 protein was elevated without significant changes in its mRNA. Clearly these results confirm the GABA cells loss after MSG neonatal treatment in both cerebral regions. As most of the GABAergic markers measured were reduced in the cerebral cortex, this region seems to be more sensitive than hippocampus, where interesting compensatory changes over GAD65 and GAD67 proteins were observed. However, it is possible that others neurotransmission systems are also compensating the GABA-positive cells loss in the cerebral cortex, and that elevations in two main forms of GAD in the hippocampus are not sufficient to maintain the neural excitation threshold for this region. Crown Copyright © 2009

    Gastropods and bivalves of commercial interest from the continental shelf of Jalisco and Colima, México

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    The distribution and abundance with respect to depth and type of substratum of 20 species of gastropods and four species of bivalves of economic importance were examined in the continental shelf of Jalisco and Colima, México. These species were taken with net trawls at depths from 24 to 83 m in August, 1988. Most individuals and species of gastropods were collected in stations with sandy silt substratum. Bivalves were collected in sandy silt and medium sand substrata. The six most abundant species represented 81.2 % of all gastropods and bivalves collected. These species are: Cantharus pallidus, Fusinus dupetittouarsi, Ficus ventricosa, Hexaplex brassica, Harpa conoidalis and Arca pacifica

    Modification of dopaminergic markers expression in the striatum by neonatal exposure to glutamate during development

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    Monosodium l-glutamate (MSG) was administered subcutaneously to male neonatal rats, and the effect on developmental profile of tyrosine hydroxylase (TH), D1, D2 receptors, and dopamine (DA) transporter expression in the striatum was examined using Western blot. In addition, TH-immunopositive neurons at substantia nigra (SN) were also examined. MSG treatment (4 mg/g of body weight, administered on postnatal days 1, 3, 5, and 7) resulted in a reduction of D1 and D2 receptor expression from 30 days of age and persisted to adulthood (120 days of age), while DA transporter expression was significantly reduced from 14 days of age to adulthood. TH immunopositive neurons at SN showed a significant reduction, as well as TH expression on postnatal days 10, 30, 60, and 120 at striatum was reduced. No changes of TH were observed at 14 days of age. Results indicate that an over-stimulation of the glutamatergic system by neonatal exposure to a high glutamate concentration induces a partial loss in TH-positive neurons in the SN and an important reduction in dopaminergic markers expression in the striatum, suggesting that early excitotoxicity could contribute to developmental alterations in the nigrostriatal pathway, which may be associated with various disorders of the basal ganglia. © 2004 ISDN. Published by Elsevier Ltd. All rights reserved

    Astrocytic and microglia cells reactivity induced by neonatal administration of glutamate in cerebral cortex of the adult rats

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    Recent studies confirm that astrocytes and neurons are associated with the synaptic transmission, particularly with the regulation of glutamate (Glu) levels. Therefore, they have the capacity to modulate the Glu released from neurons into the extracellular space. It has also been demonstrated an intense astrocytic and microglia response to physical or chemical lesions of the central nervous system. However, the persistence of the response of the glial cells in adult brain had not been previously reported, after the excitotoxic damage caused by neonatal dosage of monosodium glutamate (MSG) to newborn rats. In this study, 4 mg/g body weight of MSG were administered to newborn rats at 1, 3, 5, and 7 days after birth, at the age of 60 days the astrocytes and the microglia cells were analyzed with immunohistochemical methods in the fronto-parietal cortex. Double labeling to glial fibrillary acidic protein (GFAP) and BrdU, or isolectin-B4 and BrdU identified astrocytes or microglia cells that proliferated; immunoblotting and immunoreactivity to vimentin served for assess immaturity of astrocytic intermediate filaments. The results show that the neonatal administration of MSG-induced reactivity of astrocytes and microglia cells in the fronto-parietal cortex, which was characterized by hyperplasia; an increased number of astrocytes and microglia cells that proliferated, hypertrophy; increased complexity of the cytoplasm extension of both glial cells and expression of RNAm to vimentin, with the presence of vimentin-positive astrocytes. This glial response to neuroexcitotoxic stimulus of Glu on the immature brain, which persisted to adulthood, suggests that the neurotransmitter Glu could trigger neuro-degenerative illnesses. © 2002 Wiley-Liss, Inc
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