472 research outputs found

    Por ella, por la escena: la construcción de la identidad juvenil de los (chiki) punks de Lima

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    Desde su surgimiento a mediados del siglo XX el rock ha sido de especial interés para las ciencias sociales a partir el binomio de juventud y música. El presente trabajo es un estudio de caso sobre los discursos y las prácticas de los nuevos punks de Lima en el siglo XXI. Los rockeros subterráneos de los 80 bautizaron a estos jóvenes despectivamente como “chikipunks” por romper con los paradigmas que instauró el punk en el contexto nacional de los 80. Sin embargo, desde una profunda reflexividad y un inmenso acceso a información gracias al Internet, estos nuevos punks desarrollaron nuevas rebeldías frente a la hegemonía que nos ayudan a pensar en categorías como subcultura, tribu urbana y escena. Usando una metodología cuantitativa y de enfoque microsocial, esta investigación nos muestra a través de los conciertos los cambios y permanencias del género que sigue vigente con sus crecientes festivales que llegan a cifras de asistencia nunca antes vistas en el rock nacional.Tesi

    High-Velocity Estimates and Inverse Scattering for Quantum N-Body Systems with Stark Effect

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    In an N-body quantum system with a constant electric field, by inverse scattering, we uniquely reconstruct pair potentials, belonging to the optimal class of short-range potentials and long-range potentials, from the high-velocity limit of the Dollard scattering operator. We give a reconstruction formula with an error term.Comment: In this published version we have added remarks and we have edited the pape

    Prevalence and distribution of intestinal parasites in stray dogs in the northwest area of Mexico

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    Zoonotic parasitic infections are a major global public and veterinary health problem and widespread among stray dogs. The objective of this study was to establish the prevalence of intestinal parasites in stray dogs in the urban, rural and coastal areas of Mexicali County in northwest Mexico. In 2014, from January to December, 380 stray dogs were captured. The entire small intestine, cecum and faeces samples were collected and examined by using simple zinc sulfate flotation and Lugol’s solution staining. Data were statistically analysed. Overall, about 21.5% of examined dogs were found positive for intestinal parasites. Toxocara canis was the most frequent detected parasite, with a prevalence of 7.1%, followed by Toxascaris leonina (5.5%), Cystoisospora spp. (5.0%), Taenia spp. (3.9%) and Dipylidium caninum (2.8%). Dogs were more frequently found to be infected with a single genus of intestinal parasite (18.7%) than co-infected (2.8%). Intestinal parasites were more prevalent in samples from the coastal area (25%) than in those from the rural (24.4%) and urban (20.6%) areas, however, only statistical association was found between capture area and specific intestinal parasitic infection. There were significant differences in the prevalence of taeniasis among two age groups (P<0.01). A seasonal peak of prevalence for intestinal parasitic infections was found during spring (P<0.05), corresponding with a seasonal peak of prevalence of T. canis (P<0.05). The wide range of isolated parasites indicated that people residing in this area are at risk of exposure to these potentially hazardous zoonotic pathogens

    Presencia de circovirus porcino tipo 2 en hatos porcinos de Baja California, México

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    The aim of this study was to detect the presence of porcine circovirus type 2 (PCV2) in pig herds of Baja California, Mexico, using the polymerase chain reaction (PCR) technique. Blood samples (n=97) were collected from 97 pigs in 26 farms. The DNA was extracted from the buffy coat and the samples were grouped into 19 groups of five samples and one of two samples for PCR analysis. Specific primers were used to amplify a PCV2 ORF2 fragment of 264 base pairs and using a commercial vaccine as a positive control. The viral fragment was detected in 15% (3/20) of the groups. This is the first report in which the presence of porcine circovirus type 2 in Baja California is evidenced.El objetivo de este estudio fue detectar la presencia de circovirus porcino tipo 2 (PCV2) en hatos porcinos de Baja California, México, empleando la técnica de reacción en cadena de la polimerasa (PCR). Se colectaron 97 muestras de sangre de cerdos procedentes de 26 granjas. El ADN se extrajo a partir de la capa leucoplaquetaria y las muestras fueron agrupadas en 19 grupos de cinco muestras y uno de dos muestras para el análisis de PCR. Se utilizaron cebadores específicos para amplificar un fragmento de 264 pares de bases del ORF2 de PCV2 utilizando como control positivo una vacuna comercial. El fragmento viral se detectó en el 15% (3/20) de los grupos analizados. Este es el primer reporte en el que se evidencia la presencia de circovirus porcino tipo 2 en Baja California

    Detection of porcine reproductive and respiratory syndrome in porcine herds of Baja California, Mexico

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    El objetivo de este estudio fue evaluar la presencia del virus del síndrome reproductivo y respiratorio porcino genotipo 2 (VSRRP-2) en Baja California (Baja), así como la estandarización de la técnica qRT-PCR. Se realizó un estudio transversal de 2016 a 2017 en granjas de Baja. Se obtuvieron 97 muestras de sangre de verracos y cerdas clínicamente sanos y no vacunados. Se diseñaron y estandarizaron iniciadores con el fin de realizar pruebas qRT-PCR a partir de la capa leucocitaria. Todos los resultados positivos fueron confirmados por estudios de secuenciación. Se encontró que el 9.3 % de las muestras fueron positivas. Las muestras positivas provinieron del 66.6 % de las regiones muestreadas. Este estudio demuestra la presencia de VSRRP-2 en Baja, por lo tanto, es necesario realizar estudios epidemiológicos para identificar la magnitud del problema y establecer medidas preventivas y de control.The objective of this study was to assess the presence of genotype 2 porcine reproductive and respiratory syndrome virus (PRRSV-2) in Baja California (Baja), as well as the standardization of the qRT-PCR technique. A cross-sectional study was conducted from 2016 to 2017 in farms from Baja. It was obtained 97 blood samples from clinically healthy, not-vaccinated boars and sows. Primers were designed and standardize, in order to perform qRT-PCR tests from the buffy coat. Every positive results were confirmed by sequence studies. It was found that 9.3 % of the samples were positive. The positive samples came from 66.6 % of the sampled regions. This study demonstrates the presence of PRRSV-2 in Baja, therefore, it is necessary to conduct epidemiological studies in order to identify the magnitude of the problem and to establish preventive and control measures

    Cultura de investigación para la innovación y el emprendimiento

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    El libro se encuentra dividido en tres ejes temáticos : el primero trata temas de Investigación aplicada con dos capítulos, el segundo eje contiene los capítulos tres al seis y aborda temas de innovación en procesos con temas de software y competitividad empresarial; el eje tres innovación en servicios y en producción, del capítulo siete al doce aborda temas tan interesantes como las realidades de la internacionalización de servicios, logística hospitalaria, modelo de diagnóstico para el desarrollo socio-económico y modelo de microcréditos.The book is divided into three thematic axes: the first deals with issues of applied research with two chapters, the second axis contains chapters three to six and addresses issues of innovation in processes with issues of software and business competitiveness; axis three innovation in services and production, from chapter seven to twelve, addresses such interesting topics as the realities of the internationalization of services, hospital logistics, a diagnostic model for socio-economic development and a microcredit model.Cómo fomentar la investigación científica y la innovación empresarial desde una unidad de emprendimiento / Carlos Andres Zamudio Delgado, Johemir Pérez Pertuz -- Cambio y variabilidad cognitiva en el desarrollo de competencias financieras en niños y niñas de 7 años / Luis Guillermo Rojas Gómez -- FINEVA: el software para el análisis financiero de la internacionalización empresarial / Guillermo Rafael Angulo Vega, Lissette Salomé Ortíz Gallardo, Johel Andrés García Vargas -- Responsabilidad social del contador público desde su proceso de formación para fortalecer la gestión contable de microempresarios en la localidad de suba upz rincón Bogotá Colombia / Nadia Ávila, Ana C. Pinzón Vargas -- Competitividad e innovación en el aprendiz SENA: perspectivas de formación / René Alexander Guerrero Vergel, Ferly Antonio Valencia Serna, Elizabeth Tuberquia Vanegas -- Diseño y desarrollo de una aplicación de escritorio para la homologación contable de módulos sap systeme anwendungen und produkte / Nelson Giovanni Agudelo Cristancho, Ángela María Montoya, Juan Carlos Amezquita Tovar -- Realidades de la internacionalización de servicios en Colombia: una revisión de literatura (1994-2017) / Campo Elías López Rodríguez, Juan Carlos Ligarreto Parra, Haroldo Enrique Puerta Cabarcas -- Logística hospitalaria: caracterización de la operación de una sala de urgencias en la ciudad de Ibagué / Julián Alonso Garzón Quiroga, Jaime Alberto Villada Garcés -- Estudio de la evolución de la huella ocular como mecanismo de seguridad para las entidades financieras / Laura Valentina García Pérez, Karen Valentina Cetina Huérfano, Ashly Valeria Mercado Rojas, Ana C Pinzón Vargas -- Cómo vincular la información que brinda la contabilidad de gestión ambiental con los proyectos de emprendimiento / Daniel Isaac Roque -- Modelo diagnóstico para el desarrollo socio- productivo de la chamba en la post cosecha / Marina Casallas Silva, Jimmy Daniel Gamba Casallas, Wilson Ferney Molano -- Modelo de microcréditos para el sistema financiero / José Gerardo Vaca Lombanana232 página

    A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins

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    Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin similar to 100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants

    Evenness mediates the global relationship between forest productivity and richness

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    1. Biodiversity is an important component of natural ecosystems, with higher species richness often correlating with an increase in ecosystem productivity. Yet, this relationship varies substantially across environments, typically becoming less pronounced at high levels of species richness. However, species richness alone cannot reflect all important properties of a community, including community evenness, which may mediate the relationship between biodiversity and productivity. If the evenness of a community correlates negatively with richness across forests globally, then a greater number of species may not always increase overall diversity and productivity of the system. Theoretical work and local empirical studies have shown that the effect of evenness on ecosystem functioning may be especially strong at high richness levels, yet the consistency of this remains untested at a global scale. 2. Here, we used a dataset of forests from across the globe, which includes composition, biomass accumulation and net primary productivity, to explore whether productivity correlates with community evenness and richness in a way that evenness appears to buffer the effect of richness. Specifically, we evaluated whether low levels of evenness in speciose communities correlate with the attenuation of the richness–productivity relationship. 3. We found that tree species richness and evenness are negatively correlated across forests globally, with highly speciose forests typically comprising a few dominant and many rare species. Furthermore, we found that the correlation between diversity and productivity changes with evenness: at low richness, uneven communities are more productive, while at high richness, even communities are more productive. 4. Synthesis. Collectively, these results demonstrate that evenness is an integral component of the relationship between biodiversity and productivity, and that the attenuating effect of richness on forest productivity might be partly explained by low evenness in speciose communities. Productivity generally increases with species richness, until reduced evenness limits the overall increases in community diversity. Our research suggests that evenness is a fundamental component of biodiversity–ecosystem function relationships, and is of critical importance for guiding conservation and sustainable ecosystem management decisions

    Author Correction: Native diversity buffers against severity of non-native tree invasions.

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    Native diversity buffers against severity of non-native tree invasions

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    Determining the drivers of non-native plant invasions is critical for managing native ecosystems and limiting the spread of invasive species1,2^{1,2}. Tree invasions in particular have been relatively overlooked, even though they have the potential to transform ecosystems and economies3,4^{3,4}. Here, leveraging global tree databases5,6,7^{5,6,7}, we explore how the phylogenetic and functional diversity of native tree communities, human pressure and the environment influence the establishment of non-native tree species and the subsequent invasion severity. We find that anthropogenic factors are key to predicting whether a location is invaded, but that invasion severity is underpinned by native diversity, with higher diversity predicting lower invasion severity. Temperature and precipitation emerge as strong predictors of invasion strategy, with non-native species invading successfully when they are similar to the native community in cold or dry extremes. Yet, despite the influence of these ecological forces in determining invasion strategy, we find evidence that these patterns can be obscured by human activity, with lower ecological signal in areas with higher proximity to shipping ports. Our global perspective of non-native tree invasion highlights that human drivers influence non-native tree presence, and that native phylogenetic and functional diversity have a critical role in the establishment and spread of subsequent invasions
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