1,341 research outputs found

    USING RANDOM SAMPLING TO ESTIMATE INSECT COUNTS AS RESPONSE SURFACES INVOLVING SPACE AND TIME

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    In fall 2000, an on-farm sustainable agricultural research project was established for cotton (Gossypium hirstum L.) in Tift County, Georgia. Twenty fields that were to be planted to cotton in 2001 were identified which were approximately 5 to 10 acres in size. Four randomly selected fields were assigned to each of five cover crops: 1) cereal rye (Secale cereale L.); 2) crimson clover (Trifolium incarnatum L.); 3) legume mixture of balansa clover (T. michelianum Savi), crimson clover, and hairy vetch (Vicia villosa Roth); 4) previous legume mixture plus cereal rye; and 5) no cover crop (fallow) in conventionally tilled fields. Cotton was planted in two rows (36 in apart) on six foot beds. A strip was burned out in each row in the four cover treatments using paraquat so cotton could be planted. In the spring, insect counts were determined using sweep nets in the covers and when the cotton was small. Cotton plants from emergence to four weeks old were not sampled since the sweep net could break the fragile cotton plants. Five more weeks of sweep net data were collected from cotton. Insect samples after this involved whole plants since the cotton was too big for the sweep net to be effective. Each field was divided into 24 x 24 foot sample areas beginning at the center of the field. Each week for 14 or 15 weeks, 21 samples were obtained from each field. Comprising the 21 random samples were one sample from the four center plots, one sample from each of the four sides, and four samples from each of the four quadrants. Thus throughout the season, a five acre field could have most of the plots sampled at least once. Larger fields saw a smaller percentage of all the plots sampled. No interior plot excluding the center and edges was sampled a second time until every plot had been sampled once. A response surface was fitted for the weekly data for each field. As would be expected, high densities of insects resulted in a significant fit

    Non-Axisymmetric Fixed or Variable Fan Nozzle for Boundary Layer Ingestion Propulsion

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    A fan section for an engine has a fan which rotates about an axis, the fan has an inlet for ingesting ambient air, and a non-axisymmetric nozzle for providing the fan with non-uniform back pressure

    Review of the small grants mechanism

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    Reacción en el tamaño de poliquetos del fondo marino frente a diferentes regímenes nutricionales

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    Analyses of body size of abyssal polychaetes were made from sites experiencing different levels of nutrient flux in the Pacific and Atlantic Oceans. Measuring polychaetes was problematical due to high levels of fragmentation, and width of the first chaetiger was used as a surrogate for body size. Results indicated that polychaetes were significantly smaller in Atlantic areas experiencing seasonal or periodic input of phytodetritus. This observation held not just for comparison of sizes of the total assemblage but also when comparisons were made at the family and species level. Not all families showed a response. In the Atlantic, individuals belonging to the families Cirratulidae, Spionidae and Sabellidae indicated size differences, while in the Pacific spionids were significantly smaller from phytodetrital sites. At the species level, six species - all deposit feeders - were significantly smaller from phytodetrital sites, while two nominally predator/omnivore species showed an increase in size. Two hypotheses for the size frequency of the Atlantic populations from phytodetrital sites are suggested – the juvenile recruitment hypothesis where the smaller population body size is because of an influx of newly recruited juveniles; and the allometric plasticity hypothesis which postulates a physiological response from populations from non-phytodetrital areas delaying reproduction and putting more energy into growth, hence resulting in a larger body size. It is hypothesised that the larger size in non-phytodetrital sites may be a response to starvation.Se han realizado análisis sobre el tamaño de algunos poliquetos de zonas abisales marinas con diferentes niveles de flujo de nutrientes en los océanos Atlántico y Pacífico. Dada la tendencia a romperse, la medición de dichos poliquetos fué problemática. Por esta razon, la anchura del primer chaetígero se ha tomado como sustituto del tamaño total. Los resultados indican que los poliquetos eran notablemente más pequeños en zonas donde el flujo de nutrientes era estacional u ocasional. Ésta observación no solo se aplica a la totalidad de la población, sino también al nivel taxonómico familiar y por especies. No todas las familias mostraron dicha relación. En el océano Atlántico, individuos pertenecientes a las familias Cirratulidae, Spionidae y Sabellidae mostraron diferencias de tamaño, mientras que en el océano Pacífico las familias Paraonidae y Spionidae eran de menor tamaño en zonas con aportación nutritiva. Al nivel de especie, seis especies, todas ellas detritívoras, eran más pequeñas en zonas con flujo de nutrientes, y otras dos especies, ambas consideradas carnívoras/omnívoras, eran más grandes en dichas donas. Un análisis de frecuencia de los distintos tamaños de poliquetos en estas zonas demuestran que el alto numero de tamaños menores no ha sido causado por una afluencia de juveniles. Se especula que el mayor tamaño de poliquetos encontrados en zonas con flujo de nutrientes estacional se debe a una reacción de inanición. &nbsp

    Pharmacologic Treatment for Pediatric Gastroparesis: A Review of the Literature

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    There have been a number of agents that have been tried for treatment of gastroparesis over the past 3 decades, with varying levels of success. Guidelines exist for the management of gastroparesis in adults; however, even though the cause of gastroparesis in children is similar to that in adults, no guidelines exist for treating pediatric gastroparesis as studies on the topic are limited. With what little information we have on pediatric gastroparesis, medications used in children's studies do not seem to demonstrate the same results as in adult patients with gastroparesis; thus, future studies of whether certain medications are effective for treating pediatric gastroparesis and at what dose still need to be conducted. Pharmacological treatment options for pediatric gastroparesis do not show a clear correlation of resolving or even maintaining gastroparesis-associated symptoms or disease state. This article reviews the available studies of drugs that have shown some efficacy, with an emphasis on pediatric studies

    Reduced social contact and attachment insecurity as predictors of loneliness during COVID-19: A two-month experience sampling study

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    The impact of reduced social contact on mental health during the COVID-19 pandemic has been identified as a major public health concern. While personality factors such as attachment style have been associated with psychological distress during the pandemic, the longitudinal relevance of these factors and the role of daily social contact in mitigating distress remains poorly understood. This study evaluated the impact of social contact and attachment style on changes in loneliness over an 8-week experience sampling period during the COVID-19 pandemic. A general adult sample (n = 184) recruited online completed measures of psychological distress, attachment, and loneliness via smartphone. Loneliness and daily social contact were assessed twice per week for eight weeks, yielding 1124 unique observations. During the experience sampling period, proximal increases in loneliness were associated with decreased daily in-person contact. In contrast, participants who described themselves as having fewer interactions via text, phone, or videoconferencing, as well as those with higher anxious and avoidant attachment traits, reported greater experiences of loneliness over time. These findings suggest the relevance of both enduring personality characteristics and daily social behaviors as risk factors for loneliness during the pandemic, pointing to potential targets for clinical intervention and future empirical study
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