923 research outputs found
An integrated agroforestal suitability model using a GIS-based multicriteria analysis method: A case study of Portugal
It is generally agreed that the choice of the most suitable uses based in soil and climatic factors, complemented with socio-economic criteria, promotes sustainable use of rural land. There are, however, different methodologies for defining the soil suitability to agroforestal systems or natural and seminatural ecosystems, including agricultural uses, forest plantations, agro-forestry areas and priority areas for nature conservation. Many of these methods rely on decision support systems based on multicriteria spatial analysis. In this study we intended to determine the different levels of suitability for agro-forestry use in a subregion located in the center of Portugal, near the border with Spain. To the effect we used a set of soil and topographic variables. The legal constraints and land cover were also included. The suitability evaluation was performed using the Analytic Hierarchy Process (AHP). A spatial analysis was also performed in order to confront the land use matrix with the soil potentiality. This analysis allows to identify areas where the use and management it is in accordance with their suitability, as well as areas where the use must be subject to a conversion or at least to a change of management mode.info:eu-repo/semantics/publishedVersio
Bioclimatic modelling in the holocene and in future warming scenarios in Arbutus unedo L.
Growing forests wildfires in Portugal are an increasing concern since forests in the Mediterranean region are vulnerable to recent global warming. Long-term negative effects are expected on the vegetation with the coming increasing drought. The strawberry tree (Arbutus unedo L.) displays potential to be a successfully business-like cultured in several regions of Portugal and southern Europe, as it is well adapted to climate and soils. In Portugal, this species has been used by local populations particularly for spirit production and for fruit consumption, although it has different possible commercial uses, from processed and fresh fruit production to ornamental, pharmaceutical and chemical applications. In addition, due to its pioneer status, it is valuable for land recovery and desertification avoidance, besides being fire resistant. The available strawberry tree’s data is presence-only. For modelling purposes, a set of placements within the landscape of interest (Portugal) was applied. The species, observed in 318 plots, together with a vector of environmental covariates (7 bioclimatic attributes, slope and altitude) and a defined background were used for modeling purposes. Maxent 3.4.1 was the used software, where the estimated quantity is the probability of the presence of the species, conditioned on the environment. Maxent uses the environmental covariate data from the occurrence records and the background sample, to estimate the ratio between the conditional density of the covariates at the presence sites and the marginal (i.e., unconditional) density of covariates across the study area and so, estimating the relative suitability of one place vs. another. Three different climate scenarios (control run; 2050 and 2070) were tested for two emission scenarios (RCP 4.5 and RCP 8.5, WorldClim), besides the past, 6,000 BP (Mid-Holocene). The reduction of habitat suitable for this species is very significant in the southern regions, even for the best warming scenario (RCP 4.5) in 2050. Central and Northern mountain regions are predicted refuge for this species. Forest policies and management should consider the impact of climate change on the usable areas for forestry, seeing a case-study species particularly adapted to the Mediterranean regions and wildfires, such as strawberry tree. The distribution of the species in the Middle Holocene agrees with previous genetic and fossils studies in the region, which supported two putative refuges for the species since the Last Glacial Maximum and a cryptic refugia in the East-Central mountain region.info:eu-repo/semantics/publishedVersio
Dynamical phenomena in complex networks: fundamentals and applications
This special issue presents a series of 33 contributions in the area of dynamical networks and their applications. Part of the contributions is devoted to theoretical and methodological aspects of dynamical networks, such as collective dynamics of excitable systems, spreading processes, coarsening, synchronization, delayed interactions, and others. A particular focus is placed on applications to neuroscience and Earth science, especially functional climate networks. Among the highlights, various methods for dealing with noise and stochastic processes in neuroscience are presented. A method for constructing weighted networks with arbitrary topologies from a single dynamical node with delayed feedback is introduced. Also, a generalization of the concept of geodesic distances, a path-integral formulation of network-based measures is developed, which provides fundamental insights into the dynamics of disease transmission. The contributions from the Earth science application field substantiate predictive power of climate networks to study challenging Earth processes and phenomena
Physics of Psychophysics: Stevens and Weber-Fechner laws are transfer functions of excitable media
Sensory arrays made of coupled excitable elements can improve both their
input sensitivity and dynamic range due to collective non-linear wave
properties. This mechanism is studied in a neural network of electrically
coupled (e.g. via gap junctions) elements subject to a Poisson signal process.
The network response interpolates between a Weber-Fechner logarithmic law and a
Stevens power law depending on the relative refractory period of the cell.
Therefore, these non-linear transformations of the input level could be
performed in the sensory periphery simply due to a basic property: the transfer
function of excitable media.Comment: 4 pages, 5 figure
Bioclimatic modelling and environmental tolerance to global change in strawberry tree
The strawberry tree (Arbutus unedo L.) displays potential to be successfully businesslike-cultured in several areas of Portugal and southern Europe, but remains largely a neglected crop. This region is also particularly vulnerable to global warming, reduction of precipitations and a long-term negative effect on vegetation.
To investigate interactions between the species’ distribution and ecological factors we used 319 plots (1km grid level), where the species are present in Portugal, characterized with 8 ecological attributes: ombrothermic Index (OI), thermicity Index (TI) and continentality Index (CI), pH, organic matter (OM), sand, topographic position index (TPI), number of fires (NF) and burned area (BA). The obtained matrix was firstly analyzed through PCA to reduce the space of analysis by a construction of synthesis variables (Spearman’s rank correlation matrix) and thus to detect patterns within the data set and possible collinear covariates.
Finally, the vulnerability of strawberry tree to the effects of global climate change was examined. For that purpose, two ‘representative concentration pathways’ (RCPs) scenarios were predicted (RCP 2.6 and RCP 6.0) using climatic data, extracted from WorldClim, for distribution changes characterization in two periods (2050 and 2070). The MaxEnt allowed spatial Interpolation using the 319 1K plots. The PCA showed that the climatic attributes (OI, and TI) displayed the highest components’ correlation values. The strawberry tree prefers areas with higher TI and lower acidity values within the mesomediterranean and termomediterranean belts. Additionally, with lower correlation values, the presence of the species is explained by lower OI values, OM, BA and NF. The prediction results revealed reduction of the potential area of the species, providing a key tool to support conservation management decisions, to design regions of provenance, and to manage genetic improvement programs.info:eu-repo/semantics/publishedVersio
Groundwater vulnerability assessment in the Naturtejo UNESCO glogal Geopark, Portugal
Nowadays, groundwater vulnerability assessment has become a useful tool for groundwater contamination prevention. Groundwater vulnerability maps provide useful data to protect groundwater resources and work as a tool for the improvement of changes in agricultural patterns and land use applications. The study area of this research survey is the Naturtejo UNESCO Global Geopark, located in central inland Portugal and corresponding to a mainly rural territory where intensive agricultural practices showed a rising tendency in the last decades. The most used method of vulnerability evaluation is the DRASTIC index. In this survey, a modified DRASTIC method, DRASTICAI, is introduced. A new attribute designated as Anthropogenic Influence is introduced. Map algebra in a GIS environment allowed the computation of two maps by overlaying the needed attributes. The Vila-Velha-de Rodão and Idanha-a-Nova municipalities show moderate to high vulnerability and, therefore, in need of monitoring, since intensive agricultural practices are the main economic activity. The algebraic subtraction of DRASTIC and DRASTICAI maps revealed a considerable increase in the risk of contamination, over the surveyed area, namely in Idanha-a-Nova where it is observed risk increase up to 45 points, changing from moderately vulnerable to highly vulnerable and, therefore, stressing the importance of anthropogenic activities
Seleção indireta via teor de sólidos solúveis totais para identificação de bulbos de cebola com baixa pungência.
A cebola quando consumida crua é benéfica para a saúde, devido aos compostos organosulfurados e frutanas presentes nos bulbos, Entretanto, quanto mais picante (pungente), mais difícil é o consumo cru da cebola. Cebolas com menor pungência são selecionadas, tendo como referência à quantificação do ácido pirúvico. Neste trabalho, são comparadas duas formas de seleção de bulbos com baixa pungência: seleção preliminar para teor de sólidos solúveis totais (SST), considerando que a correlação é positiva com o teor de ácido pirúvico (AP), e sem seleção preliminar. Na população de cebola Alfa Tropical Ciclo III, a seleção preliminar dos bulbos com menor teor de SST apres entou em média 4,97?mol de ácido pirúvico/mL, variando de 2, 89 a 7,33, enquanto que no bulk sem seleção prévia para baixo teor de SST, a média foi de 8,89 ?mol de ácido pirúvico/mL, variando de 5,64 a 11,29. A seleção preliminar para baixo teor de SST resultou na identificação de oito bulbos, do total de 15, com teor de ácido pirúvico abaixo de 5,0 ?mol/mL, enquanto que na amostra ao acaso de 14 bulbos, nenhum bulbo foi identificado. A seleção indireta via SST resultou na economia de reagentes e tempo e é, portanto, recomendado para facilitar o desenvolvimento de populações de cebola doce ou superdoce.Suplemento. Edição de Resumos expandidos e palestras do 43. Congresso Brasileiro de Olericultura, Recife, jul. 2003
Overlap between Frontotemporal Dementia and Bipolar Disorder: a case report
A variante comportamental da demência frontotemporal (DFTvc) apresenta-se frequentemente com sintomas psiquiátricos, entre os quais alterações comportamentais e da personalidade. Antes do estabelecimento dos défices cognitivos, a diferenciação entre a DFTvc e outras perturbações psiquiátricas pode ser desafiante.
Este artigo apresenta um caso de um episódio maníaco com sintomas psicóticos num doente de 61 anos cujas alterações da personalidade e as dificuldades na realização das tarefas diárias não só se mantiveram, como se agravaram após o tratamento da sintomatologia maniforme e psicótica. Após estudo posterior com avaliação neuropsicológica formal, tomografia computorizada crânio-encefálica (TC-CE) e SPECT
cerebral, estabeleceu-se o diagnóstico provável de DFTvc.
O presente caso atenta para a possível progressão de formas atípicas e tardias de Perturbação Bipolar (PB) para Demências Frontotemporais. Têm sido propostas várias ligações entre DFT e PB, entre as quais se destacam o envolvimento do gene C9ORF72 em alguns doentes com PB que posteriormente evoluem para demência.info:eu-repo/semantics/publishedVersio
Biostratigraphic calibration of seismic units in the offshore Algarve Basin: contribution of core SWIM04-39
[RESUMO] Efectuou-se a calibração estratigráfica das unidades sísmicas mais recentes identificadas na Bacia offshore do Algarve recorrendo à análise biostratigráfica (Nanofósseis calcários e Foraminíferos) do core de pistão SWIM04-39. Obteve-se uma idade de cerca de 4.0 Ma (Pliocénico Inferior, Zancliano) para as associações fitoplanctónica e faunística presente nas amostras do referido core. Estes dados permitiram datar o início da intensa subsidência sofrida por esta Bacia como sendo Pliocénico Inferior. [ABSTRACT] Biostratigraphic calibration of the seismic units recognized in the offshore Algarve Basin was made, based on the identification of Calcareous nanofossil and Foraminifera assemblages present in the core SWIM04-39. An age of about 4.0 Ma (Early Pliocene, Zanclean) was determinate for these assemblages. Using this data is possible to place the beginning of subsidence movements in the offshore Algarve Basin during the Early Pliocene.publishersversionpublishe
Tejo Internacional. Guia de Visita.
Em sintonia com os objetivos fixados aquando da criação do Parque Natural do Tejo Inernacional, em agosto de 2000, assume-se como propósito deste guia a apresentação de um instrumento de informação e orientação que potencie o respeito pelos valores intrínsecos do PNTI, bem como o usufruto e fruição equilibrada dos mesmos. Neste contexto procede-se a uma breve descrição caracterizadora do Território do Parque, informação relativa ao apoio à visitação, é ainda apresentado um elenco de espécies de fauna e flora.info:eu-repo/semantics/publishedVersio
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