669 research outputs found
Efficacy of soybean seed treatments in Iowa and the effect of cold stress on damping-off caused by Pythium sylvaticum
Soybean (Glycine max (L.) Merr.) production is negatively affected by the occurrence of seedling diseases. In Iowa, the occurrence of seedling diseases is commonly associated with cool and wet weather soon after planting, and several Pythium spp. have been found as the predominant pathogens causing seedling disease. Increasing cost of the seed, risk of seedling diseases reducing stand in cold, wet soils, and the yield benefit sometimes provided by early planting have motivated an increase in the use of fungicide seed treatment. However, a positive effect of seed treatments on soybean plant stand and yield has not been clearly demonstrated in Iowa. This study was conducted to: (i) compare the effect of commercially available soybean seed treatments on plant stand and yield; (ii) assess the effect of cold stress at planting on the incidence of Pythium seedling disease and efficacy of a commercial seed treatment; and (iii) evaluate the effect of chilling temperatures after planting on the Pythium – soybean interaction.
Each year, three small plot field studies were conducted at different locations in Iowa in 2014, 2015 and 2016. Fifteen seed treatments were evaluated in 2014, and 13 seed treatments in 2015 and 2016. The experimental design was a randomized complete block with four replications. Seeding rate was 140.000 seeds per acre in 2014, and 120.000 seed per acre in 2015 and 2016. Periods of cool and wet weather soon after planting were observed in seven of nine trials within 4 to 7 days after planting. Enhancement of plant stand and yield by seed treatment was inconsistent among treatments and locations, even in trials where adverse weather conditions were observed soon after planting. Moreover, no bean leaf beetle (Cerotoma trifurcate) injury was observed, low soybean cyst nematode (SCN) (Heterodera glycines) populations were measured at the trial sites, and sudden death syndrome (SDS) (Fusarium virguliforme) foliar disease index was in the trials was also low. Based on these findings, seed treatment may not be indispensable to achieve high plant stands in Iowa and should be regarded as a preventive control measure to protect soybean stand from seedling disease. Even though our results were inconclusive, as suggested by other authors farmers should consider the use of seed treatments in field has a history of SDS, SCN, or seedling disease particularly in early planting.
The effect of cold stress on efficacy of a seed treatment containing metalaxyl and ethaboxam (Intego SuiteTM) on soybean emergence was evaluated in a growth chamber experiment. A five-way factorial design with two cold stress temperatures (4ÃÂúC and 10ÃÂúC), two times for the initiation of cold stress (24 and 96 hours after planting), three cold stress durations (24, 48 and 96 hours), and two levels of seed treatments (Intego SuiteTM and untreated) was conducted in cups inoculated with Pythium sylvaticum or a non-inoculated control. Emergence was reduced when the pathogen was present, and longer periods of cold stress further reduced emergence. No differences where observed between times for the initiation of cold stress. The cold stress had no effect on emergence when the pathogen was absent. Seed treatment protected soybean seedlings subjected to periods of cold stress. Seed treatment also resulted in improved shoot weight and reduced root rot severity. The results from this study demonstrated that seed treatment is a useful management tool to protect seedlings from damping-off caused by P. sylvaticum when soybeans are planted under suboptimal temperatures.
To improve understanding of the effect of cold stress on Pythium damping-off, growth chamber and laboratory experiments were performed. A growth chamber study was conducted to test the effect of a 96-hour period of cold stress at different times after planting on soybean damping-off. The experimental design was a three way factorial with two cold stress temperatures (4ÃÂúC and 10ÃÂúC); seven levels of timing of the initiation of cold stress (no cold stress, 0, 1, 2, 4, 6, 8 days planting); and inoculation with P. sylvaticum-infested millet or sterile millet (non-inoculated control). Increased susceptibility to damping-off was observed when soybeans were subjected to cold stress. Emergence was assessed 21 days after planting and was particularly low when cold stress occurred 2 or 4 days after planting in inoculated cups. In the non-inoculated controls, no effect of cold stress on emergence was observed. Also, emergence and seedling growth was delayed when P. sylvaticum was present. In a laboratory experiment, mycelial growth of P. sylvaticum on diluted V8 media was assessed at different temperatures (4ÃÂúC, 10ÃÂúC and 18ÃÂúC). Low temperatures delayed mycelial growth but the pathogen was still able to grow at 4ÃÂúC. In another experiment, seed exudation was assessed by measuring electrical conductivity. Greater seed exudation was detected when soybean seeds were imbibed at 4ÃÂúC compared to 10ÃÂúC and 18ÃÂúC. Sporangia of P. sylvaticum germinated in response to seed exudates, and sporangial germination increased when cultures were exposed to seed exudates from seeds imbibed at 4ÃÂúC. These results demonstrate that the timing of cold stress during seed germination play an important role in the occurrence of damping-off caused by P. sylvaticum. Moreover, low temperatures increase seed exudation and may enhance activity of P. sylvaticum.
The results from this study have improved our understanding of the soybean-Pythium interaction and conditions that favor disease development. These data will aid soybean farmers in Iowa in making their decisions whether or not to use a seed treatment
Prueba de habilidades prácticas CCNP
La prueba de habilidades prácticas para el curso DIPLOMADO DE PROFUNDIZACIÓN CISCO CCNP, se realiza para abordar y conocer los temas de importancia que conforman el curso como forma de aprendizaje acerca del proceso de enrutamiento y configuración avanzado usando equipos activos en la conformación de redes como switches, router y otros elementos que conforman una red; segmentándola usando las VLAN para enviar paquetes por la red de destino a través de equipos conectados transportando el tráfico por capa dos y capa tres respectivamente ocupando protocolos como: IP, OSPF, usando rutas estáticas y evidenciando adyacencias convergentes en la red. También se desarrollan temas que forman parte del módulo CCNP ROUTE R&S y al módulo CCNP SWITCH R&S. En el presente trabajo abordaremos dos escenarios en los cuales demostraremos las habilidades para desarrollar la configuración y administración de dispositivos de Networking orientados al diseño de redes escalables y de conmutación, cuyos conocimientos fueron obtenidos en el transcurso del curso de profundización. Se utilizará además para la simulación en software Packet Tracer.The test of practical skills for the CISCO CCNP DIPLOMA DEPTHENING course, is made to approach and to know the important subjects that conform the course as form of learning about the process of routing and advanced configuration using active equipment in the conformation of networks like switches, router and other elements that conform a network; segmenting it using the VLANs to send packages by the destiny network through connected equipment transporting the traffic by layer two and layer three respectively occupying protocols like IP, OSPF, using static routes and evidencing converged adjacencies in the network. We also develop topics that are part of the CCNP ROUTE R&S module and the CCNP SWITCH R&S module. In this paper we will address two scenarios in which we will demonstrate the skills to develop the configuration and management of networking devices oriented to the design of scalable and switching networks, whose knowledge was obtained during the course of the in-depth course. It will also be used for simulation in Packet Tracer software
Enabling Massive Deep Neural Networks with the GraphBLAS
Deep Neural Networks (DNNs) have emerged as a core tool for machine learning.
The computations performed during DNN training and inference are dominated by
operations on the weight matrices describing the DNN. As DNNs incorporate more
stages and more nodes per stage, these weight matrices may be required to be
sparse because of memory limitations. The GraphBLAS.org math library standard
was developed to provide high performance manipulation of sparse weight
matrices and input/output vectors. For sufficiently sparse matrices, a sparse
matrix library requires significantly less memory than the corresponding dense
matrix implementation. This paper provides a brief description of the
mathematics underlying the GraphBLAS. In addition, the equations of a typical
DNN are rewritten in a form designed to use the GraphBLAS. An implementation of
the DNN is given using a preliminary GraphBLAS C library. The performance of
the GraphBLAS implementation is measured relative to a standard dense linear
algebra library implementation. For various sizes of DNN weight matrices, it is
shown that the GraphBLAS sparse implementation outperforms a BLAS dense
implementation as the weight matrix becomes sparser.Comment: 10 pages, 7 figures, to appear in the 2017 IEEE High Performance
Extreme Computing (HPEC) conferenc
A review of cardiopulmonary research in brazilian medical journals: clinical, surgical and epidemiological data
Research in the field of cardiopulmonary disease in Brazil has been very active in recent decades. The combination of PUBMED, SCieLO, open access and online searching has provided a significant increase in the visibility of Brazilian journals. This newly acquired international visibility has in turn resulted in the appearance of more original research reports in the Brazilian scientific press. This review is intended to highlight part of this work for the benefit of the readers of "Clinics." We searched through PUBMED for noteworthy articles published in Brazilian medical journals included in the Journal of Citation Reports of the Institute of Scientific Information to better expose them to our readership. The following journals were examined: "Arquivos Brasileiros de Cardiologia," "Arquivos Brasileiros de Endocrinologia e Metabologia," "Brazilian Journal of Medical and Biological Reviews," "Jornal Brasileiro de Pneumologia," "Jornal de Pediatria," "Revista Brasileira de Cirurgia Cardiovascular," "Revista da Associação Médica Brasileira," Revista da Escola de Enfermagem U.S.P." and "São Paulo Medical Journal." These journals publish original investigations in the field of cardiopulmonary disease. The search produced 71 references, which are briefly examined
La pobreza energética en mujeres rurales mexicanas: el adobe como tecnologÃa sustentable
La relevancia de este estudio radica en la convicción de que los esfuerzos de apoyo al desarrollo rural, en especial a los millones de personas que viven en condiciones de pobreza extrema en México, deben orientarse, al acceso limpio, accesible y sustentable de energÃa como un factor que puede propiciar el desarrollo económico y la reducción de la pobreza. Esta es una investigación con perspectiva de género, orientada hacia el desarrollo rural a partir del diseño, cuyo objetivo es implementar tecnologÃas sustentables para la obtención de energÃa. La metodologÃa contempla, trabajo etnográfico con visitas de campo, registros fotográficos y entrevistas a profundidad en tres comunidades de extrema pobreza del Estado de México. La investigación presenta un análisis de las opciones más viables para la obtención de energÃa sustentable, dando como resultado la utilización de adobe en la construcción de estufas o fogones y diseños más eficientes
The contributions of an alternative learning environment and some individual affective factors in the development of the communicative competence a case study
El presente estudio pretende determinar cómo un ambiente alternativo de aprendizaje asà como algunos factores individuales afectivos contribuyen al desarrollo de la competencia comunicativa en dos sujetos de estudio. Los autores exploraron un ambiente de aprendizaje alternativo, teniendo en cuenta la teorÃa subyacente a los siguientes constructos: ambientes de aprendizaje, competencia comunicativa y los factores individuales afectivos, con estos constructos se diseñó una rejilla que integrara algunos de sus elementos más relevantes con el fin de analizar los datos recogidos a través de observaciones y grabaciones. Acto seguido, con la ayuda de la rejilla, los autores diagnosticaron hasta qué punto los elementos seleccionados tuvieron lugar en el ambiente alternativo de aprendizaje. Finalmente, se identificaron las tendencias dominantes y se detectaron cuáles de estos elementos influÃa en realidad en el desarrollo de la competencia comunicativa en los dos sujetos de estudio. Los resultados mostraron que existen elementos dominantes que parecen contribuir en el Desarrollo de la Competencia Comunicativa de los dos sujetos de estudio. En relación con el Ambiente de Aprendizaje (Wilson, 1996), este no daba oportunidades a los sujetos de estudio para desarrollar su competencia comunicativa ya que se evidenciaba una falta de interacción entre los participantes debido a los estilos de enseñanza y de manejo de autoridad de parte del profesor. En cuanto a la Competencia Comunicativa, el uso de las estrategias comunicativas (Celce-Murica, 1995-2000) tuvo un rol fundamental para los dos participantes ya que estos usaron las estrategias con diferentes objetivos a lo largo de las sesiones observadas. Referente a los Factores Individuales Afectivos, la confianza en sà mismos influenció en gran medida el desenvolvimiento de los sujetos porque ésta parecÃa permear a las otras dos categorÃas de análisis. Durante las etapas de observación y análisis, se identificó una categorÃa emergente: estilos de enseñanza y estilos de autoridad. Al parecer esta categorÃa afectó cada uno de los constructos en diferentes maneras: en la construcción del ambiente de aprendizaje, en la exposición de diferentes situaciones que permitieran el uso de todas las sub-competencias de la Competencia Comunicativa, y de manera general a los factores individuales afectivos.The present study intends to determine how an alternative learning environment and some individual affective factors contribute to the development of Communicative Competence of two subjects. The authors explored an alternative learning environment taking into reference the theory behind the constructs of Learning Environment, Communicative Competence, and Individual Affective Factors, and a grill that integrated some of the elements of these three constructs was designed with the purpose of analyzing the data collected through observations and videotaping. Subsequently, with the help of the grill, the authors diagnosed the extent to which the selected elements took place in the alternative learning environment. Finally, the dominant trends were identified to detect which of the elements selected actually influenced the development of Communicative Competence of two subjects, an 18 year old men and a 30 year old girl who study in the institute, and how. The results showed that there are dominant elements that seemed to contribute to the development of both participants Communicative Competence. Regarding Learning Environment (Wilson, 1996), the selected one did not provide students with opportunities for them to develop their Communicative Competence since there was lack of interaction among the participants due to the teachers teaching and authority styles. Concerning Communicative Competence, the use of the Communicative Strategies (Celce-Murcia, 1995-2000) played a fundamental role for both participants since they used the strategies for diverse purposes in all the sessions observed. Referring to the Individual Affective Factors, Self-confidence had a significant influence in the participants performance because it seemed to permeate the other two categories of analysis.Licenciado (a) en Lenguas ModernasPregrad
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