3,510 research outputs found

    In vitro biocontrol activity of Trichoderma harzianum on Alternaria alternata in the presence of growth regulators

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    http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-34582001000200006&lng=es&nrm=isoThe in vitro biocontrol ability of Trichoderma harzianum on the phytopathogen Alternaria alternata improved in the presence of the growth regulators gibberellic acid (GA3), or indolacetic acid (IAA) or benzylaminopurine (BAP) or foliar nutrient at concentrations similar or higher than those used at the field level. These plant hormones decreased the secretion of endopolygalacturonase (endo-PG) of A. alternata by approximately 20%, did not modify endochitinase (endo-CH) secretion of T. harzianum and did not alter germination of conidia or mycelia growth of any of these fungi. The presence of T. harzianum decreased endo-PGase secretion of A. alternata by about 50%. This inhibitory effect was independent of the presence of growth regulators. The level of secreted endo-PG of T. harzianum was not modified by the presence of A. alternata, but the presence of this phytopathogen in cultures of T. harzianum, increased both the growth of the biocontroller and its secretion of endo-CH

    Selection of bioantagonistic bacteria to be used in biological control of Rhizoctonia solani in tomato

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    http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602011000100002&lng=es&nrm=isoBacteria from the rhizoplane and surrounding soil of healthy and Rhizoctonia solani diseased tomato plants, cropped in greenhouse of the V Region of Chile, were collected. The best bacterial strains, based on their ability to control development of three R. solani isolates (identified as belonging to the anastomosis groups AG-2-1, AG-4), were identified as B. subtilis (one isolate) and B. lentimorbus (two different isolates). All bacterial isolates resulted effective for the in vitro control of growth of all R. solani isolates, where the control mechanisms used by the bacteria do not involve the secretion of fungal cell wall hydrolytic enzymes. R. solani AG-2-1 was more sensitive than R. solani AG-4. On the other hand, all bacteria grew well in conditions similar to those that can be found at the field level (considering pH, salinity, Fe3+ and temperature) and showed a good capacity of tomato root colonization. These results suggest that the B. subtilis and B. lentimorbus isolates studied have an excellent potential to be used as biocontrol agents of R. solani in tomato greenhouses at the field level

    Periodismo en línea y desarrollo de blogs como alternativa de expresión informativa

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    El término “blog” proviene de las palabras Web y Log, y se ha convertido en unaherramienta de recuento de historias paralelas, ya que a través de ellos es posiblevisualizar distintas interpretaciones a un mismo acontecimiento.Si bien el origen de los blogs es personal, a últimas fechas los medios periodísticosen línea han colocado blogs como recurso de interacción entre sus lectores. Esto lesha arrojado retroalimentación, y ha permitido obtener una sensibilidad directa de laopinión pública en formación y promueve nuevos temas a insertarse en la agenda.El presente trabajo revisa los blogs como alternativas de información al recursoperiodístico, analizando el comportamiento de los blogs insertados en diversosperiódicos y sitios de información periodística en línea

    Noticia sobre las prospecciones arqueológicas realizadas en la partida de El Campo (Villena, Alto Vinalopó)

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    El Museu Arqueològic “José María Soler” de Villena va iniciar en 2006 un projecte d’investigació sobre el poblament antic a la vall de Villena, del qual es presenten els resultats de la primera campanya de prospeccions realitzada a la partida d’“El Campo”, en la qual es coneixien vestigis d’època romana. L’actuació arqueològica ha constatat la presència d’establiments tardoantics dels segles VI-VII i, també, altmedievals, que permeten confeccionar una seqüència més vasta i completa en aquesta part del territori, que comprén des de la Prehistòria recent fins a la Baixa Edat Mitjana. Paraules clau: Prospecció arqueològica. Època romana. Època tardoromana. Època altmedieval. Poblament.The “José María Soler” Archaeological Museum of Villena began a research project at the old settlement of the Villena Valley in august 2006. In this article we present the results of the first archaeological field survey campaign carried out at the site of “El Campo”, in the north of the valley. Traditionally, this area had provided vestiges from Roman times. The materials located this year have been fundamentally pottery, although of a great novelty, because they inform us, for the first time ever, of the presence of late ancient establishments of the 6th-7th centuries and likewise, of the Early Medieval Age, all of which would allow us to have a wider sequence in this part of the territory encompassing from the recent Prehistory up to the Lower Medieval Age. Key words: Archaeological survey. Roman period. Late Roman period. Upper Medieval period. Settlement.El Museo Arqueológico “José María Soler” de Villena dio inicio, en 2006, a un proyecto de investigación sobre el poblamiento antiguo en el valle de Villena, del que se presentan los resultados de la primera campaña de prospecciones realizada en la partida de “El Campo”, en la que se conocían vestigios de época romana. La actuación arqueológica ha constatado la presencia de asentamientos tardo-antiguos de los siglos VI-VII y, también altomedievales, que permiten confeccionar una secuencia más vasta y completa en esta parte del territorio, que comprende desde la Prehistoria reciente a la baja edad Media. Palabras clave: Prospección arqueológica. Época romana. Época tardo- romana. Época altomedieval. Poblamiento

    Impacto del uso de las tecnologías de información y las comunicaciones en la gestión judicial de la Dirección Seccional de Administración Judicial de Cúcuta

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    El Consejo Superior de la Judicatura ha adelantado programas de modernización tecnológica, tanto de los despachos judiciales como de los entes de administración de la rama judicial, pero aún se puede constatar la generalización del atraso judicial y consecuentemente, la pérdida de credibilidad en el sistema. Objetivo: Determinar el impacto que tiene el uso de las tecnologías de información y las comunicaciones en la gestión judicial de la Dirección Seccional de Administración Judicial de Cúcuta. Métodos: Se utilizó un tipo de estudio descriptivo, aplicado a 25 jueces, 115 empleados de los diferentes despachos judiciales y a 5 magistrados quienes fueron actores clave para el estudio. Resultados: Los resultados indican que el impacto de las TIC en la gestión judicial de la Entidad es moderado basado en las limitaciones actuales del flujo de información con los usuarios y con las demás entidades de la rama judicial. Conclusión: No se ha integrado el sistema de información con todos los municipios de la región de Norte de Santander y Arauca. Adicionalmente, a pesar que se cuenta con herramientas tecnológicas para mantener interactividad con proveedores y usuarios del servicio judicial, el personal de la Entidad no los conoce completamente por la resistencia al cambio que supone realizar las tareas de diferente manera.The Superior Council of the Judiciary has advanced technological modernization programs, both judicial offices as the administration offices of the judicial branch, but it can still observe the generalization of the judicial delay and consequently the loss of credibility in the system. Objective: To determine the impact of the use of information technologies and communications in judicial management of Departmental Office of Judicial Administration Cucuta. Methods: A type of descriptive study applied to 25 judges, 115 employees of the various judicial offices and 5 judges who were key actors for the study was used. Results: The results indicate that the impact of ICT in the judicial management is moderate based on the current limitations of the flow of information with users and with other institutions of the judiciary. Conclusion: No integrated information system with all the municipalities of the region of Norte de Santander and Arauca. Additionally, although it has technological tools to maintain interaction with providers and users of judicial services, the staff of the entity not fully understood by the resistance to change that is to perform tasks differently

    Importancia del uso de las plataformas virtuales en la formación superior para favorecer el cambio de actitud hacia las TIC: estudio de caso. Universidad del Magdalena, Colombia

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    El propósito de la investigación fue analizar el cambio actitudinal en los estudiantes de pregrado acerca del uso de la plataforma virtual como apoyo al desarrollo de un curso de formación disciplinar impartido en la modalidad presencial, considerando los aportes de Vygotsky (1988), Ausubel (1983), Pozo (2001), Coll (2007), Marqués (2001; 2003), Prensky (2001), Vilaseca y Meseguer (2000), entre otros. El estudio corresponde a un estudio de caso, enmarcado en el paradigma cualitativo, que utilizó como técnicas el grupo focal y dos encuestas que permitieron apreciar la opinión de los estudiantes del dominio las TIC y la actitud por el uso de la plataforma virtual como apoyo a la clase presencial o Aprendizaje Semipresencial. Contó con la participación de 35 estudiantes de Licenciatura en Preescolar en la Universidad del Magdalena en Santa Marta (Colombia) en el periodo académico 2012-I. Se evidenció que la interacción presencial no es el único canal comunicativo que garantiza aprendizajes efectivos y más allá del incremento de la habilidad tecnológica en los estudiantes, se contribuyó a elevar la autoestima, a mejorar el tiempo de dedicación en la realización de actividades complementarias a los encuentros presenciales. A los docentes les permite establecer las pautas para participar tanto en el entorno presencial como el virtual, la asignación de ejercicios y trabajos para presentar en cada espacio, los plazos de publicación de actividades y los criterios de evaluación.The purpose of this research was to analyze the attitudinal change in undergraduate students about their use of the virtual platform to support the development of a training course in the classroom, considering the contributions of Vygotsky (1988), Ausubel (1983), Pozo (2001), Coll (2007), Marqués (2001; 2003), Prensky (2001), Vilaseca y Meseguer (2000). Is a case study, framed within the qualitative paradigm, which used as techniques a focus group and two surveys designed to appreciate the opinions and attitudes from the students on the TIC’s in the use of a virtual platform to support the Blended Learning. The research involved 35 undergraduate students of Preschool education in the Universidad del Magdalena in Santa Marta (Colombia) on the first academic period of 2012. It was evident that the clasroom interaction is not the only way of communication that ensures an effective learning and increase the students abilities beyond the tecnological system, improving time commitment in the follow-up activities to face meetings. The research also allowed teachers to establish guidelines to participate not only in the classroom, but on a virtual environment, assignig exercises and assignments to be presented in each space, the due dates of every activity and the evaluation criteria

    Biocontrol of root and crown rot in tomatoes under greenhouse conditions using Trichoderma harzianum and Paenibacillus lentimorbus. Additional effect of solarization

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    Indexación: ScieloTrichoderma harzianum 650 (Th650) and Paenebacillus lentimorbus 629 (Pl629) selected earlier for their ability to control Rhizoctonia solani, Fusarium solani and F. oxysporum in vitro, were applied alone or combined with solarization (summer assay) and/or with methyl bromide (MeBr) (summer and winter assays) to a soil with a high inoculum level, for the control of tomato root rot caused by the complex F. oxysporum f. sp. lycopersici - Pyrenochaeta lycopersici - Rhizoctonia solani. Evaluations were also performed independently for root damage caused by P. lycopersici, and also for R. solani in the summer assay. MeBr decreased tomato root damage caused by the complex from 88.7% to 21.2% and from 78.4% to 35.7% in the summer and in the winter assay, respectively. None of the bio-controllers could replace MeBr in the winter assay, but Th650 and Pl629 reduced root damage caused by this complex in the summer assay. Treatments with bio-controllers were improved by their combination with solarization in this season. Independent evaluations showed that the positive control of Th650 towards R. solani and the lack of effect on P. lycopersici correlates well with the endochitinase pattern expressed by Th650 in response to these phytopathogens. Root damage caused by R. solani can be controlled at a similar level as it does MeBr in summer assays, thus representing an alternative to the use of this chemical fungicide for the control of this phytopathogen.Financial support: Fondecyt 1990785

    Feeding of a pelagic chaetognath, Sagitta friderici Ritter-Záhony off Ubatuba region (São Paulo, Brazil)

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    The diet of Sagitta friderici off Ubatuba region, São Paulo State, was studied in March, 1989. Specimens were collected with a closing-net during three days at six hours' intervals (00:00; 06:00; 12:00; 18:00 h), at a fixed station of 38 m depth. The population was composed basically by young stages (O-II). A total of 3175 specimens were examined but only 760 contained preys in their guts. Copepods were the main constituent of food eaten (79.86%). There was a preference for the genera Paracalanus, Oncaea, Corycaeus and for crustacean nauplii. Other zooplanktonic groups such as Annelida, Urochordatha, and Mollusca were also found in the gut. Cannibalistic behavior occurred in 2.66% of the samples. In S. friderici the food was selected by size and was a direct function of the predator size. Younger stages (O-I) selected small prey, whereas older stages (II) preferred larger preys. Specimens collected above the thermocline exhibited higher feeding intensity (FCR) during the night periods.Espécimens de Sagitta friderici foram coletados numa estação fixa de 38 m de profundidade, ao largo de Ubatuba, Estado de São Paulo, em março de 1989. Arrastos verticais, acima e abaixo da termoclina, foram feitos com rede de fechamento (50 cm de diâmetro de boca e malha de 0.200 mm) durante três dias consecutivos e em intervalos de seis horas. O estudo de 3175 indivíduos, nos estágios de O-IV, revelou que 2415 apresentaram o trato digestivo vazio e 760 com algum tipo de alimento. Destes últimos, 283 continham material amorfo e os 473 restantes de 1 a 3 presas. Das 488 presas identificadas, 99,74% estavam localizadas na região posterior do trato digestivo e 0,26% na região anterior. A dieta de S. friderici esteve constituída de Crustácea, Annelida, Urochordata, Chaetognatha e Mollusca. Dentre os Crustácea, os Copepoda foram os mais abundantes, predominando os Calanoida e Cyclopoida. O estágio 0 de S. friderici teve preferência pelos náuplios de crustáceos, enquanto que uma maior diversificação do alimento, incluindo a prática do canibalismo, foi observada a partir do estágio I. Não houve diferenças significativas na composição da dieta dos indivíduos coletados nos diferentes períodos do dia. Os espécimens de S. friderici coletados acima da termoclina apresentaram maior porcentagem de tratos digestivos (FCR) contendo alimento

    Measuring the Effectiveness of Static Maps to Communicate Changes over Time

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    Both in digital and print media, it is common to use static maps to show the evolution of values in various regions over time. The ability to communicate local or global trends, while reducing the cognitive load on readers, is of vital importance for an audience that is not always well versed in map interpretation. This study aims to measure the efficiency of four static maps (choropleth, tile grid map and their banded versions) to test their usefulness in presenting changes over time from a user experience perspective. We first evaluate the effectiveness of these map types by quantitative performance analysis (time and success rates). In a second phase, we gather qualitative data to detect which type of map favors decision-making. On a quantitative level, our results show that certain types of maps work better to show global trends, while other types are more useful when analyzing regional trends or detecting the regions that fit a specific pattern. On a qualitative level, those representations which are already familiar to the user are often better valued despite having lower measured success rate

    Statistical supervised learning with engineering data: a case study of low frequency noise measured on semiconductor devices

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    The authors thank the Laboratory of Nanoelectronics in the Research Centre for Information and Communications Technologies (CITIC-UGR) at the University of Granada (Spain) for providing the data for the study. This work was supported in part by the Spanish Ministry of Science and Innovation through grants number RTI2018-099723-B-I00, and PID2020-120217RB-I00; the Spanish Junta de Andalucia through grants number B-FQM-284-UGR20 and B-CTS-184-UGR20; and the IMAG-Maria de Maeztu grant CEX2020-001105-/AEI/10.13039/501100011033. The comments from two anonymous reviewers and the Associate Editor that have helped to improve the quality of the paper are also acknowledged.Our practical motivation is the analysis of potential correlations between spectral noise current and threshold voltage from common on-wafer MOSFETs. The usual strategy leads to the use of standard techniques based on Normal linear regression easily accessible in all statistical software (both free or commercial). However, these statistical methods are not appropriate because the assumptions they lie on are not met. More sophisticated methods are required. A new strategy based on the most novel nonparametric techniques which are data-driven and thus free from questionable parametric assumptions is proposed. A backfitting algorithm accounting for random effects and nonparametric regression is designed and implemented. The nature of the correlation between threshold voltage and noise is examined by conducting a statistical test, which is based on a novel technique that summarizes in a color map all the relevant information of the data. The way the results are presented in the plot makes it easy for a non-expert in data analysis to understand what is underlying. The good performance of the method is proven through simulations and it is applied to a data case in a field where these modern statistical techniques are novel and result very efficient.Spanish Government RTI2018-099723-B-I00 PID2020-120217RB-I00Junta de Andalucia B-FQM-284-UGR20 B-CTS-184-UGR20IMAG-Maria de Maeztu grant CEX2020-001105-/AE
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