Trilce XXV de César Vallejo: Crítica y contrapunto

El poema XXV de Trilce (1922) ha corrido con desigual suerte entre los críticos. Algunos (Yurkievich, Neale-Silva) insisten en el valor expresivo y en la fuerza poética frente a las dificultades de comprensión; otros (Larrea, Coyné) parecen más bien inclinados a considerarlo como "un ejemplo consumado de esa expresión que la estilística ha llamado caótica."1 De cualquier modo, Trilce XXV no es uno de los poemas más comentados de Vallejo, a pesar de que representa semejante grado de complejidad que, por ejemplo, Trilce 1. Tampoco es el poema de antología de César Vallejo.2 A pesar de todo ello nos atrevemos a pensar que es uno de los más perfectos del poeta peruano

LA LITERATURA MEXICANA COMO SISTEMA

LA LITERATURA MEXICANA COMO SISTEM

La tradición retórica en la poética y en la historia

138 páginas.Tres textos que enfatizan la importancia de la tradición retórica en el México decimonónico para las artes liberales en general y para la creación literaria y la historia en particular. El primero, del Dr. Jorge Ruedas de la Serna, se ocupa de la importancia de la preceptiva y estudia el tránsito de las poéticas del siglo XVIII al XIX. El segundo, escrito por la Dra. María Luna Argudín, analiza la relación entre tradición retórica, representación del pasado y escritura de la historia. Por su parte, el comentario preparado por la Mtra. Leticia Algaba, explora los vasos comunicantes entre las tesis propuestas en los dos textos anteriores.Consejo Nacional de Ciencia y Tecnología (México)

Drive of a brushless direct current motor with hall type sensors

In the present article, an electronic bi-directional power converter applied to the control of a brushless direct current motor (Brushless) was designed, implemented and automatically activated, by means of which part of the electric bicycle is recovered. The kinetic energy is converted to electrical energy efficiently, with a positive ecological impact. The converters were implemented with isolated gate transistors (IGBT), these devices have high switching frequency, which allows significantly reduce the harmonics, which is very attractive in different applications therefore the results of this work can be generalized for the speed control of higher power direct current motors which can not be fed directly from the electrical system and require a variable speed, as is the case of electric vehicles.En el presente artículo se diseño, implemento y se caracterizo un convertidor electrónico de potencia bidireccional aplicado al control de un motor de corriente directa sin escobillas (Brushless), para el impulso de una bicicleta eléctrica de modo automático, mediante el cual se recupera parte de la energía cinética y se convierte a energía eléctrica de modo eficiente, con un impacto ecológico positivo. Los convertidores se implementaron con transistores de compuerta aislada (IGBT), estos dispositivos tienen alta frecuencia de conmutación, lo que permite reduce significativamente los armónicos, lo cual es muy atractivo en diferentes aplicaciones por lo tanto los resultados del presente trabajo se pueden generalizar para el control de velocidad de motores de corriente directa de mayor potencia los cuales no puedan ser alimentados directamente del sistema eléctrico y requieran de una velocidad variable, como es el caso de los vehículos eléctricos

Primary Angioplasty in a Catastrophic Presentation: Acute Left Main Coronary Total Occlusion—The ATOLMA Registry

Objectives. To determine the outcome predictors of in-hospital mortality in acute total occlusion of the left main coronary artery (ATOLMA) patients referred to emergent angioplasty and to describe the clinical presentation and the long-term outcome of these patients.Background. ATOLMA is an uncommon angiographic finding that usually leads to a catastrophic presentation. Limited and inconsistent data have been previously reported regarding true ATOLMA, yet comprehensive knowledge remains scarce.Methods. This is a multicenter retrospective cohort that includes patients presenting with myocardial infarction due to a confirmed ATOLMA who underwent emergency percutaneous coronary intervention (PCI).Results. In the period of the study, 7930 emergent PCI were performed in the five participating centers, and 46 of them had a true ATOLMA (0.58%). At admission, cardiogenic shock was present in 89% of patients, and cardiopulmonary resuscitation was required in 67.4%. All the patients had right dominance. Angiographic success was achieved in 80.4% of the procedures, 13 patients (28.2%) died during the catheterization, and the in-hospital mortality rate was 58.6% (27/46). At one-year and at the final follow-up, 18 patients (39%) were alive, including four cases successfully transplanted. Multivariate analysis showed that postprocedural TIMI flow was the only independent predictor of in-hospital mortality (OR 0.23, (95% CI 0.1-0.36),p<0.001).Conclusions. Our study confirms that the clinical presentation of ATOLMA is catastrophic, presenting a high in-hospital mortality rate; nevertheless, primary angioplasty in this setting is feasible. Postprocedural TIMI flow resulted as the only independent predictor of in-hospital mortality. In-hospital survivors presented an encouraging outcome. ATOLMA and left dominance could be incompatible with life

Experimental Evidence for Reduced Rodent Diversity Causing Increased Hantavirus Prevalence

Emerging and re-emerging infectious diseases have become a major global environmental problem with important public health, economic, and political consequences. The etiologic agents of most emerging infectious diseases are zoonotic, and anthropogenic environmental changes that affect wildlife communities are increasingly implicated in disease emergence and spread. Although increased disease incidence has been correlated with biodiversity loss for several zoonoses, experimental tests in these systems are lacking. We manipulated small-mammal biodiversity by removing non-reservoir species in replicated field plots in Panama, where zoonotic hantaviruses are endemic. Both infection prevalence of hantaviruses in wild reservoir (rodent) populations and reservoir population density increased where small-mammal species diversity was reduced. Regardless of other variables that affect the prevalence of directly transmitted infections in natural communities, high biodiversity is important in reducing transmission of zoonotic pathogens among wildlife hosts. Our results have wide applications in both conservation biology and infectious disease management

Phylogeny, Diet, and Cranial Integration in Australodelphian Marsupials

Studies of morphological integration provide valuable information on the correlated evolution of traits and its relationship to long-term patterns of morphological evolution. Thus far, studies of morphological integration in mammals have focused on placentals and have demonstrated that similarity in integration is broadly correlated with phylogenetic distance and dietary similarity. Detailed studies have also demonstrated a significant correlation between developmental relationships among structures and adult morphological integration. However, these studies have not yet been applied to marsupial taxa, which differ greatly from placentals in reproductive strategy and cranial development and could provide the diversity necessary to assess the relationships among phylogeny, ecology, development, and cranial integration. This study presents analyses of morphological integration in 20 species of australodelphian marsupials, and shows that phylogeny is significantly correlated with similarity of morphological integration in most clades. Size-related correlations have a significant affect on results, particularly in Peramelia, which shows a striking decrease in similarity of integration among species when size is removed. Diet is not significantly correlated with similarity of integration in any marsupial clade. These results show that marsupials differ markedly from placental mammals in the relationships of cranial integration, phylogeny, and diet, which may be related to the accelerated development of the masticatory apparatus in marsupials

Sin Nombre Virus and Rodent Species Diversity: A Test of the Dilution and Amplification Hypotheses

BACKGROUND:Species diversity is proposed to greatly impact the prevalence of pathogens. Two predominant hypotheses, the "Dilution Effect" and the "Amplification Effect", predict divergent outcomes with respect to the impact of species diversity. The Dilution Effect predicts that pathogen prevalence will be negatively correlated with increased species diversity, while the Amplification Effect predicts that pathogen prevalence will be positively correlated with diversity. For many host-pathogen systems, the relationship between diversity and pathogen prevalence has not be empirically examined. METHODOLOGY/PRINCIPAL FINDINGS:We tested the Dilution and Amplification Effect hypotheses by examining the prevalence of Sin Nombre virus (SNV) with respect to diversity of the nocturnal rodent community. SNV is directly transmitted primarily between deer mice (Peromyscus maniculatus). Using mark-recapture sampling in the Spring and Fall of 2003-2005, we measured SNV prevalence in deer mice at 16 landscape level sites (3.1 hectares each) that varied in rodent species diversity. We explored several mechanisms by which species diversity may affect SNV prevalence, including reduced host density, reduced host persistence, the presence of secondary reservoirs and community composition. We found a negative relationship between species diversity and SNV prevalence in deer mice, thereby supporting the Dilution Effect hypothesis. Deer mouse density and persistence were lower at sites with greater species diversity; however, only deer mouse persistence was positively correlated with SNV prevalence. Pinyon mice (P. truei) may serve as dilution agents, having a negative effect on prevalence, while kangaroo rats (Dipodomys ordii), may have a positive effect on the prevalence of SNV, perhaps through effects on deer mouse behavior. CONCLUSIONS/SIGNIFICANCE:While previous studies on host-pathogen systems have found patterns of diversity consistent with either the Dilution or Amplification Effects, the mechanisms by which species diversity influences prevalence have not been investigated. Our study indicates that changes in host persistence, coupled with interspecific interactions, are important mechanisms through which diversity may influence patterns of pathogens. Our results reveal the complexity of rodent community interactions with respect to SNV dynamics

Molecular Approach to the Identification of Fish in the South China Sea

BACKGROUND: DNA barcoding is one means of establishing a rapid, accurate, and cost-effective system for the identification of species. It involves the use of short, standard gene targets to create sequence profiles of known species against sequences of unknowns that can be matched and subsequently identified. The Fish Barcode of Life (FISH-BOL) campaign has the primary goal of gathering DNA barcode records for all the world's fish species. As a contribution to FISH-BOL, we examined the degree to which DNA barcoding can discriminate marine fishes from the South China Sea. METHODOLOGY/PRINCIPAL FINDINGS: DNA barcodes of cytochrome oxidase subunit I (COI) were characterized using 1336 specimens that belong to 242 species fishes from the South China Sea. All specimen provenance data (including digital specimen images and geospatial coordinates of collection localities) and collateral sequence information were assembled using Barcode of Life Data System (BOLD; www.barcodinglife.org). Small intraspecific and large interspecific differences create distinct genetic boundaries among most species. In addition, the efficiency of two mitochondrial genes, 16S rRNA (16S) and cytochrome b (cytb), and one nuclear ribosomal gene, 18S rRNA (18S), was also evaluated for a few select groups of species. CONCLUSIONS/SIGNIFICANCE: The present study provides evidence for the effectiveness of DNA barcoding as a tool for monitoring marine biodiversity. Open access data of fishes from the South China Sea can benefit relative applications in ecology and taxonomy

Pedro Henríquez Ureña, biógrafo de la independencia

Conferencia /// Pedro Henríquez Ureña, biógrafo de la independencia. Jorge Ruedas de la Serna (FFyL). Modera: Norma de los Ríos Méndez. //// Semestre 2011-2. Cátedra Extraordinaria de Estudios Latinoamericanos y del Caribe. Pedro Henríquez Ureña. Secretaría Académica. Facultad de Filosofía y Letras. Universidad Nacional Autónoma de México. Aula Magna 22 de febrero de 2011. 19 minutos. //// Universidad Nacional Autónoma de México, Embajada de la República Dominicana, El Colegio de México, FLACSO-México. //// Descarga: Pulse botón derecho del ratón sobre el archivo de audio "mp3" que elija y seleccione "Guardar Destino Como...