441 research outputs found

    Population structure, recruitment and distribution patterns of Patella depressa Pennant, 1777 on the central Portuguese coast

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    Using in situ individual measurements at two levels of the shore during a one-year period, recruitment peaks of Patella depressa Pennant, 1777, possibly related to breeding periods, were identified during autumn-winter. Recruits were associated with lower levels on the shore, and juveniles mainly inhabited Mytilus galloprovincialis Lamarck, 1819 patches. Niche partitioning, intraspecific competition, and desiccation stress are discussed as decisive factors in the different size-class distributions found. A mark-recapture growth study was made at two substrata within study sites, one substratum with irregular depressions mainly composed of Chthamalus spp., and a second regular substratum comprising mostly bare rock. Our results indicated lower growth increments in the irregular substratum zone, probably due to space availability and limited foraging activity.Utilizando mediciones individuales in situ a dos niveles de la orilla durante un año, se han identificado en otoño-invierno los picos de reclutamiento de Patella depressa Pennant, 1777 relacionados, posiblemente, con los periodos de reproducción. Los reclutamientos se asocian con bajos niveles en la orilla y juveniles ocupando principalmente pequeñas extensiones junto a Mytillus galloprovincialis Lamarck, 1819. Se discute la influencia del reparto de nichos, la competencia intraespecífica y el estrés por desecación como factores decisivos en las distribución de las distintas clases de tallas encontradas. Se ha hecho un estudio de marcado y recaptura en dos sustratos comparando uno con otro: un primer sustrato con depresiones irregulares compuesto principalmente por Chthamalus spp. y un segundo, regular, compuesto fundamentalmente por rocas desnudas. Nuestros resultados indicaron incrementos bajos de crecimiento en la zona de sustrato irregular, probablemente debido a la limitada disponibilidad de espacio y a la actividad de forraje.Instituto Español de Oceanografí

    Sistem Tataniaga Kentang di Kecamatan Hatu-Builiko, Kabupaten Ainaro, Timor Leste

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    Marketing system in important part in agribusiness system with forming connectivity of agriculture produck from farmers to the final consumer. The marketing system wil influence product purchasing including divides of benefit. Use of descriptive method Analysis in this research is aims to clarify how are the potato producing in Hatu-Builiko Sub-District delivery to the market consume. The purpose of the research to determine how far the channel marketing involve, hows the marketing function applied to the condition of the market and which marketing channel mostly efficient trough margin marketing and farmer share. The sample of location and sample of farmer were selected by purposive sampling method; and the sample of trades was selected trough snowbowling sampling method. The number of farmers was selected 20 peoples and the number of trades was selected fourteen peoples.the technical coleteing data was by observation and direct interview. The research conducted in Hatu-Builiko Sub District at Ainaro District of Timor Leste. The result, there were three channel of marketing applied, mostly the three marketing channel function were selling potatoin Ainaro District market. Market structure was conducted as monophony for the farmers, monopoly for the trade collector and free competition for the retailer and wholesalers. The market behavior was elaborate in good way between farmers and trade collector and either between trade collector and retailer and also trade collector and wholesalers. The payment procedure was cash based. The most efficient marketing channel wascontributing the best value as the result of margin marketing and farmer share which is was third marketing channel

    Reproduction of Patella depressa Pennant, 1777 on the central Portuguese coast

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    The reproductive cycle and the sex ratio of the limpet Patella depressa Pennant, 1777 were studied on two rocky shores of the central coast of the Portugal, over a period of one year. The gonads were examined and their stage of development was assessed. The gonads of P. depressa were found to develop mainly from September/October to December, and between February and April. The spawning peaks occurred in January and between May and August. From June to August the gonads seem to go into a resting phase. In P. depressa the sex proportions seem to be approximately equal, suggesting the absence of sex reversal in these limpets. High wind speed under optimum conditions of air temperatures appears to induce spawning in this species.Estudiamos el ciclo reproductor y la proporción de sexos de la lapa Patella depressa Pennant, 1777 en dos litorales rocosos de la costa central de Portugal. Examinamos las gónadas y valoramos su fase de desarrollo. Encontramos gónadas de P. depressa desarrollándose principalmente desde septiembre/octubre hasta diciembre y entre febrero y abril. Los picos de puesta aparecieron en enero y entre mayo y agosto. Las gónadas parecen permanecer en una fase de reposo desde junio hasta agosto. En P. depressa la proporción de sexos parece ser aproximadamente uno, lo que sugiere la ausencia de inversión sexual en estas lapas. Bajo condiciones óptimas de temperatura del aire, la alta velocidad del viento parece inducir la puesta en esta especie.Instituto Español de Oceanografí

    Estimation of secondary production of the Faro/ Ancão artificial reefs

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    The secondary productivity of reef epifauna is one of the least investigated aspects in artificial reef research. During the first 12 months after the deployment of the Faro/Ancao (Algarve, Portugal) artificial reef, we assessed the effect of substratum orientation on the secondary production of epibenthos, using the Boysen-Jensen method. Whenever the method could not be applied, secondary production was estimated by the P/B ratio. The results showed that the epibenthic production was higher on the horizontal surface throughout the study. However, at the end of the study period, the mean production showed similar values. The horizontally oriented surfaces showed a mean production between 128 and 103 g m-2 yr-1, while at the vertical surfaces the mean production varied between 103 and 98 g m-2 yr-1. Furthermore, the mean annual production was extrapolated for all the Algarve artificial reef complex, and we concluded that after one year of deployment theses artificial reefs were able to generate around 5 MT of epibenthic fauna

    Dinâmica da atrazina no solo do Cerrado: influência da matéria orgânica na sorção e mineralização.

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    A atrazina, um herbicida seletivo recomendado para o controle de plantas daninhas principalmente na cultura do milho, é um dos mais utilizados no Brasil. Devido ao seu uso expressivo, tem sido frequentemente detectada em concentrações acima do limite máximo permitido em amostras de água e solo. Assim, objetivando avaliar o potencial contaminante deste herbicida, este trabalho visa estudar as diferentes interações da atrazina com o solo natural oriundo de uma região de monocultura de milho localizada no município de Rio Paranaíba (MG). O estudo proposto constou da avaliação da degradação da atrazina em solos com diferentes históricos de aplicação do herbicida e da avaliação da sorção da atrazina e de seus principais metabólitos no solo com e sem aplicação de matéria orgânica e correção de pH. Foram realizados ensaios de caracterização geotécnica, análises químicas e difração de raios-X. Para a avaliação do comportamento deste herbicida no solo, foram realizados ensaios de fluxo, utilizando ensaios de coluna em laboratório e coleta de amostras em diferentes profundidades no campo. Com os resultados obtidos foi possível verificar o processo de degradação da atrazina em diferentes condições físicas e químicas do solo condicionado principalmente ao histórico da sua aplicação no campo

    Which game narratives do adolescents of different gameplay and sociodemographic backgrounds prefer? a mixed-methods analysis

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    OBJECTIVE: The aim of this study was to investigate which narrative elements of digital game narratives are preferred by the general adolescent population, and to examine associations with gender, socioeconomic status (SES), and gameplay frequency. Further, the study aims to discuss how results can be translated to serious digital games. MATERIALS AND METHODS: Adolescents were recruited through school to complete a survey on narrative preferences in digital games. The survey included questions on sociodemographic information, frequency of gameplay, and an open-ended question on what could be an appealing narrative for them. Data were analyzed in a mixed-methods approach, using thematic analysis and chi-square analyses to determine narrative preferences and the associations between game narrative elements and player characteristics (gender, SES, and frequency of gameplay). RESULTS: The sample consisted of 446 adolescents (12-15 years old) who described 30 narrative subthemes. Preferences included human characters as protagonists; nonhuman characters only as antagonists; realistic settings, such as public places or cities; and a strong conflict surrounding crime, catastrophe, or war. Girls more often than boys defined characters by their age, included avatars, located the narrative in private places, developed profession-related skills, and included a positive atmosphere. Adolescents of nonacademic education more often than adolescents of academic education defined characters by criminal actions. Infrequent players more often included human characters defined by their age than frequent players. After performing a Bonferroni correction, narrative preferences for several gender differences remained. CONCLUSION: Different narrative elements related to subgroups of adolescents by gender, SES, and frequency of gameplay. Customization of narratives in serious digital health games should be warranted for boys and girls; yet, further research is needed to specify how to address girls in particular

    Bacillus thuringiensis via tratamento de sementes e solo para o controle de ninfas e adultos de Bemisia tabaci biótipo B.

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    A mosca-branca é uma importante praga de diversos cultivos por causar danos diretos pela sucção da seiva da planta e indiretos, principalmente, pela transmissão de vírus que reduz significativamente a produção. Diante disso, avaliou-se a eficiência de Bacillus thuringiensis via tratamento de sementes e solo no controle de ninfas e adultos em casa telada da Embrapa Arroz e Feijão, Santo Antônio de Goiás, GO.Siconbiol
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