5 research outputs found
Mechanical versus manual harvest of Pinus pinea cones
Umbrella pine cone production is an important forest non-wood product in Portugal,especially in the region of Alcácer do Sal, where it plays an important role to the local development. Traditionally umbrella pine cones are manually harvested, increasing production costs and, above all, with very high accident risk to the workers. The development of equipment for mechanical harvesting started in Italy in the 1980's. Studies report different values for harvesting efficiency and tree damage, the latter in terms of immature cones and branches detached. In this study a trunk shaker was used to evaluate mechanical harvesting both in terms of efficiency and tree damage induced by trunk vibration. In comparison to the manual process, time required for mechanised harvesting was about 1/15th of the time. The results revealed a mechanical harvesting efficiency higher than 86% with negligible tree damage. Inter-annual harvest efficiency variability was also observed
Medição e mapeamento da condutividade eléctrica aparente do solo em pastagens Mesurement and mapping the apparent soil electrical conductivity in pastures
O objectivo geral deste estudo foi testar uma sonda de indução electromagnética para avaliar a variabilidade do solo e da pastagem num projecto de agricultura de precisão. Esta avaliação é a base para a gestão diferenciada da fertilização, principal ferramenta utilizada pelos agricultores para melhoria das pastagens permanentes em Portugal. O processo tradicional de amostragem e avaliação do solo e da pastagem é muito exigente em tempo, trabalho e reagentes e pode comprometer um projecto de agricultura de precisão. Este artigo descreve as principais etapas seguidas pelos autores para simplificar a metodologia de avaliação baseada na medição da condutividade eléctrica aparente do solo. Os ensaios foram realizados numa parcela com aproximadamente 6 hectares de área, que foi subdividida em quadrÃculas de 28 m de lado. As amostras de solo e de pastagem e a avaliação da condutividade eléctrica do solo foram georeferenciadas com um GPS-RTK. Os dados geoespaciais foram processados com o software ARCGIS 9.3 seguido de análise de regressão ponderada geograficamente. Os resultados obtidos conduziram a valores significativos dos coeficientes de regressão entre a condutividade eléctrica e a altimetria, o pH do solo e a produtividade da pastagem, em termos de matéria seca.<br>The general objective of this study was to test a non contact electromagnetic induction probe to evaluate the soil and pasture variability in a precision agriculture project. Assessment of the variability of soil and vegetation in a permanent pasture are the basis for management of variable rate fertilization, which is the main instrument used by farmers for improvements in permanent pasture in Portugal. The traditional process of sampling and evaluation of the soil and pastures is very demanding in terms of time, labour and reagents, and can derail a project of precision agriculture. This paper describes the major steps followed by the author to simplify the methodology of soil evaluation in a permanent pasture based on measuring the apparent soil electrical conductivity. Tests were carried out in a parcel of approximately 6 hectares, which was subdivided into 28m by 28m squares. The soil and pasture samples and the evaluation of apparent electrical conductivity were georeferenced with a Global Positioning System. The geospatial data were processed by ARCGIS 9.3 software and Geographically Weighted Regression analysis, resulting in significant correlation coefficient values for apparent electrical conductivity and altimetry, soil pH and pasture dry matter yield
Efeito da topografia na estabilidade temporal dos parâmetros do solo numa pastagem permanente mediterrânica Effect of topography on temporal stability of soil parameters in mediterranean permanent pastures
Com o objectivo de avaliar o efeito da topografia na estabilidade espacial e temporal dos macronutrientes, da matéria orgânica e do pH no solo em pastagens permanentes Mediterrânicas, no perÃodo entre 2004 e 2010, foi conduzido um ensaio numa pastagem biodiversa. Para efeitos de amostragem georeferenciada do solo, uma parcela com cerca de 6 ha foi subdividida em 20 quadrÃculas de 56 m de lado. A topografia da parcela mostrou uma influência significativa sobre a dinâmica dos nutrientes no solo e pode ser utilizada em combinação com diferentes tipos de informação agronómica para ajudar a explicar a variabilidade dos nutrientes no solo. O pH foi a única caracterÃstica quÃmica do solo que manteve uma elevada estabilidade, quer espacial, quer temporal ao longo dos seis anos de ensaio. Estes resultados confirmam a complexa dinâmica dos nutrientes em pastagens Mediterrânicas envolvendo dois sistemas biológicos, plantas e animais e dificulta a implementação de estratégias de gestão diferenciada.In order to evaluate the effect of topography on spatial and temporal stability of macronutrients, organic matter and pH of soil in Mediterranean permanent pastures, between 2004 and 2010, an experiment was carried out in a bio-diverse pasture. For geo-referenced soil sampling, a 6 ha field was divided into 20 squares, with 56 m sides. Field topography showed a significant influence on the dynamics of soil nutrients and can be used in combination with different types of agronomic information to explaining the soil nutrients variability. pH was the only soil chemical characteristic that presented a high spatial and temporal stability during the six years of the experiment. These results confirm the complex dynamic of the soil nutrients in Mediterranean pastures involving two biological systems, plants and animals, and difficult the site-specific management strategy implementation
Calibração e validação de um medidor de capacitância num projecto de agriculturade precisão em pastagens Calibration and validation of an electronic capacitance meter in a pasture precision agriculture project
O objectivo deste trabalho consistiu em calibrar uma sonda electrónica de capacitância para simplificar o processo de avaliação da pastagem num projecto de Agricultura de Precisão. O método tradicional de determinação da massa de pastagem exige um grande esforço e é incompatÃvel com a gestão do dia a dia dos agricultores. Os ensaios foram realizados em diferentes datas do ano de 2007, em três explorações agrÃcolas, que representam as pastagens tÃpicas do Alentejo (gramÃneas; leguminosas; e mistura biodiversa). Foram utilizadas equações de regressão para relacionar a massa de matéria seca obtida na medição directa com as estimativas indirectas obtidas nas leituras de capacitância. Em dois dos três locais os coeficientes de determinação foram elevados, 0,90 nas gramÃneas e entre 0,67 e 0,75 na mistura biodiversa. Nas leguminosas o coeficiente de determinação variou entre 0,27 e 0,59. Em 2008 as equações de previsão foram validadas em dois dos locais, tendo-se obtido um desvio entre a massa efectivamente cortada e a massa estimada igual ou inferior a 20%.The general objective of the study was calibrate an electronic capacitance meter to estimating the pasture dry matter in a precision agriculture project. The standard method of assessing pasture requires great effort and farmers are not willing to make this effort in day-to-day management of pastures. The field tests for carrying out in different dates of 2007 and in three dairy farms, represents the typical pastures in Alentejo region (grasses; leguminous; and bio divers mixture). Regression techniques are used to relate the weight of the herbage in kg of dry matter for hectare to the meter reading of capacitance. The estimation of dry matter of the herbage mass, in kg ha-1, based in capacitance was relatively good in two sites, with overall coefficients of determination of 0,90 in grasses and 0,67 to 0,75 in bio divers mixture. In the leguminous the coefficients of determination obtained varied between 0,27 and 0,59. In 2008, the regression equations were validated in two sites and the results showed a gap between the mass effectively cut and the estimated mass of less or equal to 20%
A Novel Genetic Variant in <i>MBD5</i> Associated with Severe Epilepsy and Intellectual Disability: Potential Implications on Neural Primary Cilia
Disruptions in the MBD5 gene have been linked with an array of clinical features such as global developmental delay, intellectual disability, autistic-like symptoms, and seizures, through unclear mechanisms. MBD5 haploinsufficiency has been associated with the disruption of primary cilium-related processes during early cortical development, and this has been reported in many neurodevelopmental disorders. In this study, we describe the clinical history of a 12-year-old child harboring a novel MBD5 rare variant and presenting psychomotor delay and seizures. To investigate the impact of MBD5 haploinsufficiency on neural primary cilia, we established a novel patient-derived cell line and used CRISPR-Cas9 technology to create an isogenic control. The patient-derived neural progenitor cells revealed a decrease in the length of primary cilia and in the total number of ciliated cells. This study paves the way to understanding the impact of MBD5 haploinsufficiency in brain development through its potential impact on neural primary cilia