Auto and crosscorrelograms for the spike response of LIF neurons with slow synapses

An analytical description of the response properties of simple but realistic neuron models in the presence of noise is still lacking. We determine completely up to the second order the firing statistics of a single and a pair of leaky integrate-and-fire neurons (LIFs) receiving some common slowly filtered white noise. In particular, the auto- and cross-correlation functions of the output spike trains of pairs of cells are obtained from an improvement of the adiabatic approximation introduced in \cite{Mor+04}. These two functions define the firing variability and firing synchronization between neurons, and are of much importance for understanding neuron communication.Comment: 5 pages, 3 figure

The herpetofauna of Hidalgo, Mexico: Composition, distribution, and conservation status

The herpetofauna of Hidalgo, Mexico, is comprised of 203 species, including 42 anurans, 17 caudates, one crocodylian, 137 squamates, and six turtles. Here, the distribution of the herpetofaunal species are catalogued among the four recognized physiographic regions. The total number of species varies from 77 in the Mexican Plateau to 166 in the Sierra Madre Oriental. The individual species occupy from one to four regions (mean = 2.1). About 69% of the Hidalgo herpetofauna is found in only one or two of the four regions, which is of considerable conservation significance. The greatest number of single-region species occupies the Sierra Madre Oriental (25), followed by the Gulf Coastal Lowlands (15), the Trans-Mexican Volcanic Belt (6), and the Mexican Plateau (2). The Coefficient of Biogeographic Resemblance (CBR) indicates that the Sierra Madre Oriental and the Gulf Coastal lowlands share the most species (72), because of their adjacent geographic position and they contain a significant number of generalist species that occur in the Gulf lowlands of Mexico, southern USA, Central America, and/or South America. The two largest geographic regions in Hidalgo by area, Sierra Madre Oriental and Mexican Plateau, reflect opposite patterns in species richness (166 and 77 species, respectively) due to overall differences in the ecological characteristics between them. A similarity dendrogram based on the Unweighted Pair Group Method with Arithmetic Averages (UPGMA) depicts two distinct clusters, one between the Sierra Madre Oriental and Gulf Coastal Lowlands and the other between the Mexican Plateau and Trans-Mexican Volcanic Belt. The former cluster reflects the two regions sharing a substantial number of herpetofaunal species that occur on the Gulf lowlands of North America and Central America, as well as a few that enter South America. The second cluster is due to the two montane regions being adjacent to one another and their ecological similarities. With respect to the distributional categories, the largest number of species is that of the country endemics (104 of 203), followed by non-endemics (92), state endemics (four), and non-natives (three). The principal environmental threats to the Hidalgo herpetofauna are deforestation, livestock, roads, pollution of water sources, cultural factors, and diseases. The conservation status of each native species was assessed by means of the SEMARNAT (NOM-059), IUCN, and EVS systems, of which the EVS system was the most useful. The Relative Herpetofaunal Priority (RHP) method was also used to designate the rank order significance of the physiographic regions and the highest values were found for the Sierra Madre Oriental. Most of the five protected areas in Hidalgo are located in the Trans-Mexican Volcanic Belt, which is only the second most important region from a conservation perspective. In addition, only 78 of the 200 native species found in Hidalgo are recorded in total from the five protected areas. Finally, a set of conclusions and recommendations are offered for the future protection of the Hidalgo herpetofauna

Regionalización de la variación temporal del factor de turbidez linke TL en México a partir de algoritmos de machine learning

CIES2020 - XVII Congresso Ibérico e XIII Congresso Ibero-americano de Energia SolarRESUMEN: El agrupamiento de áreas geográficas, por medio de análisis de clusters, es una tarea que permite identificar regiones de acuerdo a los comportamientos de las variables geoclimáticas. En este trabajo de investigación se agrupó al TL Linke en regiones similares de la república mexicana de acuerdo con su varianza temporal anual del año 2015. Mediante algoritmos y técnicas de Machine Learning (aprendizaje automático), como son las mezclas de gaussianos mixtos y análisis de componentes principales, se han obtenido dos mapas, de 10 y 9 regiones que permiten identificar de una manera visual dichas regiones y analizar el comportamiento del TL Linke en la república mexicana.ABSTRACT: The clustering of geographic zones, by cluster analysis, is a task which enables to identify geographic’s regions according to the behavior of geoclimatic’s variables. In this work, the TL Linke was grouped in similar regions in the Mexico country according to the temporal annual variance of the year 2015. Using machine learning algorithms and techniques like Gaussian mixture models and principal components analysis, we obtained two maps of 10 and 9 regions which enables identify and analyze the TL Linkes behavior on Mexico country.info:eu-repo/semantics/publishedVersio

Consultoría integral en una empresa de servicios de ingeniería estructural y supervisión e inspección de estructura en el municipio de Guadalajara

Este reporte de consultoría integral en una empresa de servicios de ingeniería estructural y supervisión e inspección de estructura en el municipio de Guadalajara ha sido elaborado por Ricardo Enrique Salinas Quintero, Luis Daniel Muñoz Guerrero, Álvaro Rizzo Martínez, Javier Jiménez Ruiz, Miguel Moreno Morrill, y Karla Nicole Welcomme Delgado, con la dirección de las profesoras Laura Tiburcio Silver y María Elena Ríos Morfín. El documento se estructura por la descripción del proyecto, los aprendizajes, las conclusiones, fuentes consultadas, y lista de anexos. Al efecto, se trabajó con la metodología de la consultoría en MYPE del Centro Universidad Empresa. Las fuentes primarias utilizadas fueron los archivos proporcionados por la empresa, así como las entrevistas y las reuniones con el empresario y los colaboradores. Así mismo también se utilizaron fuentes secundarias como páginas de internet y plataformas de instituciones que ayudaron a complementar la información. Los contenidos principales están integrados por las generalidades y contexto de la empresa, el diagnóstico, el planteamiento estratégico, la propuesta de mejora incluyendo el plan de acción, la implementación, los resultados obtenidos y las recomendaciones finales. Se concluye que las MYPE son empresas que están cruzando una etapa importante en su formación cuando empiezan a caminar por si solas y buscar cursar la etapa de institucionalización que toda organización desea alcanzar. Son empresas que están formadas por trabajadores amateur y empresarios que pusieron todo su tiempo, patrimonio y esfuerzo en crear un nuevo ser que influya en la sociedad y en la vida de todos sus colaboradores.ITESO, A.C

Balanced Synaptic Input Shapes the Correlation between Neural Spike Trains

Stimulus properties, attention, and behavioral context influence correlations between the spike times produced by a pair of neurons. However, the biophysical mechanisms that modulate these correlations are poorly understood. With a combined theoretical and experimental approach, we show that the rate of balanced excitatory and inhibitory synaptic input modulates the magnitude and timescale of pairwise spike train correlation. High rate synaptic inputs promote spike time synchrony rather than long timescale spike rate correlations, while low rate synaptic inputs produce opposite results. This correlation shaping is due to a combination of enhanced high frequency input transfer and reduced firing rate gain in the high input rate state compared to the low state. Our study extends neural modulation from single neuron responses to population activity, a necessary step in understanding how the dynamics and processing of neural activity change across distinct brain states

Αβ Hinders Nuclear Targeting of AICD and Fe65 in Primary Neuronal Cultures

The intracellular domain of the Alzheimer’s amyloid precursor protein (AICD) has been described as an important player in the transactivation of specific genes. It results from proteolytic processing of the Alzheimer’s amyloid precursor protein (APP), as does the neurotoxic Aβ peptide. Although normally produced in cells, Aβ is typically considered to be a neurotoxic peptide, causing devastating effects. By exposing primary neuronal cultures to relatively low Aβ concentrations, this peptide was shown to affect APP processing. Our findings indicate that APP C-terminal fragments are increased with concomitant reduction in the expression levels of APP itself. AICD nuclear immunoreactivity detected under control conditions was dramatically reduced in response to Aβ exposure. Additionally, intracellular protein levels of Fe65 and GSK3 were also decreased in response to Aβ. APP nuclear signaling is altered by Aβ, affecting not only AICD production but also its nuclear translocation and complex formation with Fe65. In effect, Aβ can trigger a physiological negative feedback mechanism that modulates its own production

Simultaneous measurement of muon neutrino quasielastic-like cross sections on CH, C, water, Fe, and Pb as a function of muon kinematics at MINERvA

This paper presents the first simultaneous measurement of the quasielastic-like neutrino-nucleus cross sections on C, water, Fe, Pb and scintillator (hydrocarbon or CH) as a function of longitudinal and transverse muon momentum. The ratio of cross sections per nucleon between Pb and CH is always above unity and has a characteristic shape as a function of transverse muon momentum that evolves slowly as a function of longitudinal muon momentum. The ratio is constant versus longitudinal momentum within uncertainties above a longitudinal momentum of 4.5GeV/c. The cross section ratios to CH for C, water, and Fe remain roughly constant with increasing longitudinal momentum, and the ratios between water or C to CH do not have any significant deviation from unity. Both the overall cross section level and the shape for Pb and Fe as a function of transverse muon momentum are not reproduced by current neutrino event generators. These measurements provide a direct test of nuclear effects in quasielastic-like interactions, which are major contributors to long-baseline neutrino oscillation data samples.Comment: 9 pages, 8 flgures, including supplemental materia