Browsing by Author "Nunes, Pedro"
Now showing 1 - 5 of 5
Results Per Page
Sort Options
- Beyond fractional anisotropy in amyotrophic lateral sclerosis : the value of mean, axial, and radial diffusivity and its correlation with electrophysiological conductivity changesPublication . Geraldo, Ana Filipa; Pereira, João; Nunes, Pedro; Reimão, Sofia; Sousa, Rita; Castelo-Branco, Miguel; Pinto, Susana; Campos, Jorge Guedes; Carvalho, MamedePurpose: This paper aims to analyze the contribution of mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) in the detection of microstructural abnormalities in amyotrophic lateral sclerosis (ALS) and to evaluate the degree of agreement between structural and functional changes through concomitant diffusion tensor imaging (DTI), transcranial magnetic stimulation (TMS), and clinical assessment. Methods: Fourteen patients with ALS and 11 healthy, age- and gender-matched controls were included. All participants underwent magnetic resonance imaging including DTI. TMS was additionally performed in ALS patients. Differences in the distribution of DTI-derived measures were assessed using tract-based spatial statistical (TBSS) and volume of interest (VOI) analyses. Correlations between clinical, imaging, and neurophysiological findings were also assessed through TBSS. Results: ALS patients showed a significant increase in AD and MD involving the corticospinal tract (CST) and the pre-frontal white matter in the right posterior limb of the internal capsule (p < 0.05) when compared to the control group using TBSS, confirmed by VOI analyses. VOI analyses also showed increased AD in the corpus callosum (p < 0.05) in ALS patients. Fractional anisotropy (FA) in the right CST correlated significantly with upper motor neuron (UMN) score (r = - 0.79, p < 0.05), and right abductor digiti minimi central motor conduction time was highly correlated with RD in the left posterior internal capsule (r = - 0.81, p < 0.05). No other significant correlation was found. Conclusion: MD, AD, and RD, besides FA, are able to further detect and characterize neurodegeneration in ALS. Furthermore, TMS and DTI appear to have a role as complementary diagnostic biomarkers of UMN dysfunction.
- O cumprimento dos programas eleitorais em Portugal: Tendências, reformas políticas e o papel dos veto players (1995-2019)Publication . Belchior, Ana Maria; Moury, Catherine; Hanenberg, Lúcio; Nunes, PedroEm que medida os partidos portugueses cumprem as promessas eleitorais? E este cumprimento corresponde a reformas de curto ou de longo prazo? Ainda: em que medida os veto players condicionam o cumprimento do mandato pelos governos? Este artigo centra-se nestas questões, analisando sete legislaturas, entre 1995 e 2019, e um total de 6367 promessas. Os resultados revelam que o nível de cumprimento é consistentemente elevado, que as promessas de curto prazo, apesar de maioritárias, têm um nível de cumprimento igual às de longo prazo, e que os veto players podem condicionar significativamente a capacidade de concretização do mandato pelo executivo.
- Modelling Monochamus galloprovincialis dispersal trajectories across a heterogeneous landscape to optimize monitoring by trapping networksPublication . Nunes, Pedro; Branco, Manuela; Van Halder, Inge; Jactel, HervéContext 14 The pine wood nematode (PWN), is an invasive species which was introduced into Europe in 15 1999. It represents a major economic and ecological threat to European forests. In Europe, the 16 maritime pine is the main host and Monochamus galloprovinciallis is its only vector. 17 18 Objectives 19 Our goal was to analyze the effect of landscape heterogeneity on the vector’s dispersal. We 20 further aimed at developing a new method to locate the origin of insects captured in a systematic 21 network of pheromone traps. 22 23 Methods 24 A mark-release-recapture experiment was carried out in a heterogeneous landscape combining 25 maritime pine plantations, clear-cuts and isolated patches of broadleaved and mixed forests in 26 the southwest of France. 27 Least-cost path analysis was used to model dispersal trajectories and assign friction values to 28 each land-use type in the landscape. We used the trap’s geographical coordinates, capture levels 29 and mean friction values of neighbouring patches to calculate a weighed barycentre and the 30 position of the release of marked beetles
- Modelling the invasion dynamics of the African citrus psyllid: The role of human-mediated dispersal and urban and peri-urban citrus treesPublication . Nunes, Pedro; Robinet, Christelle; Branco, Manuela; Franco, José CarlosThe African citrus psyllid, Trioza erytreae (Del Guercio) (Hemiptera, Triozidae), is native to tropical Africa and invasive species in North America and Europe. The main host plants are citrus, displaying a preference for lemon trees. This psyllid was recently detected in the northwest region of the Iberian Peninsula, both in Spain and Portugal. Here, we used a model combining a reaction-diffusion model to a stochastic long- distance dispersal model to simulate the invasion dynamics of T. erytreae in Portugal. The psyllid spread in Portugal was simulated between 2015 and 2021 for different combinations of model parameters: two fecundity levels; spread with and without stochastic long-distance dispersal; single or two introductions of T. erytreae; and considering or not the urban and peri-urban citrus trees, besides citrus orchards, estimated using Google Street view imagery. The incorporation of long-distance human mediated dispersal significantly improved the F1-score in the model validation using the official reports as the observed data. Concomitantly, the dispersal rate of T. erytreae in Portugal was on average about 66 km/year, whereas removing long-distance dispersal events, the observed mean was 7.8 ± 0.3 km/year. The dispersal was mainly towards the south along the coastline, where human population is concentrated. The inclusion of the estimated citrus trees outside orchards areas significantly increased the F1-score in the model validation, revealing the importance these isolated host plants hold as stepping stones for the species current invasion and possibly for other species alike
- Urban trees facilitate the establishement of non-native forest insectsPublication . Branco, Manuela; Nunes, Pedro; Roques, Alain; Fernandes, Maria Rosário; Orazio, Christophe; Jactel, HervéCities, due to the presence of ports and airports and the high diversity of trees in streets, parks, and gardens, may play an important role for the introduction of invasive forest pests. We hypothesize that areas of urban forest facilitate the establishment of non-native forest pests. Based on scientific literature and a pan-European database on non-native species feeding on woody plants, we analysed where the first detections occurred in European countries. We collected site data for 137 first detections in Europe and 508 first European country-specific records. We also estimated the percentage of tree cover and suitable habitat (green areas with trees) in buffers around detection points. The large majority of first records (89% for first record in Europe and 88% for first records in a European country) were found in cities or suburban areas. Only 7% of the cases were in forests far from cities. The probability of occurrence decreased sharply with distance from the city. The probability to be detected in urban areas was higher for sap feeders, gall makers, and seed or fruit feeders (>90%) than for bark and wood borers (81%). Detection sites in cities were highly diverse, including public parks, street trees, university campus, arboreta, zoos, and botanical gardens. The average proportion of suitable habitat was less than 10% in urban areas where the species were detected. Further, more than 72% of the cases occurred in sites with less than 20% of tree cover. Hotspots of first detection were identified along the coastal regions of the Mediterranean and Atlantic, and near industrial areas of central Europe. We conclude that urban trees are main facilitators for the establishment of non-native forest pests, and that cities should thus be intensely surveyed. Moreover, as urban areas are highly populated, the involvement of citizens is highly recommended