224 research outputs found

    Rural–urban gradient and land use in a millenary metropolis: how urbanization affects avian functional groups and the role of old villas in bird assemblage patterning

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    Abstract. Urbanization generally leads to a complex environmental gradient, ranging from almost undisturbed natural areas to highly modified urban landscapes. Here we analyse the effects of a rural–urban gradient on breeding bird communities and functional species groups in remnant natural and semi-natural areas of Rome. A total of 69 breeding bird species were found in the study area. Species richness decreased with increasing urbanization at two spatial scales: the point count station and the landscape scales. Evenness showed a negative trend from periphery to city centre, whereas for dominant species the opposite was true. Functional species groups responded to the urbanization gradient with functional group-specific patterns. Those groups linked to open habitats (nesting and habitat functional groups) decreased in abundance along the rural–urban gradient, whereas those associated with forests exhibited a mixed trend. Generalist species' occurrence increased with urbanization. As for predators and granivorous species, we found a negative relationship with urbanization whereas for omnivorous species the opposite trend was true. The distribution of old villas (large-sized remnant green areas) in the inner city areas influenced species composition along the studied gradient, usually showing higher species richness than surrounding fragments. Agricultural areas hosted richer and better balanced bird assemblages in respect to those found in urban and forested areas. Our findings proved that an urban gradient plays a major role in structuring bird communities, although the extent and distribution of land use categories was another factor that influenced avian assemblages. The presence of historical villas also influenced bird assemblages, making it possible to preserve high bird diversity even in inner city-areas

    NMR-based metabolomics in Alzheimer’s disease research: a review

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    Alzheimer’s disease (AD) is a progressive neurodegenerative disorder and represents the most common cause of dementia in the elderly population worldwide. Currently, there is no cure for AD, and the continuous increase in the number of susceptible individuals poses one of the most significant emerging threats to public health. However, the molecular pathways involved in the onset and progression of AD are not fully understood. This information is crucial for developing less invasive diagnostic instruments and discovering novel potential therapeutic targets. Metabolomics studies the complete ensemble of endogenous and exogenous metabolites present in biological specimens and may provide an interesting approach to identify alterations in multiple biochemical processes associated with AD onset and evolution. In this mini review, we summarize the results from metabolomic studies conducted using nuclear magnetic resonance (NMR) spectroscopy on human biological samples (blood derivatives, cerebrospinal fluid, urine, saliva, and tissues) from AD patients. We describe the metabolic alterations identified in AD patients compared to controls and to patients diagnosed with mild cognitive impairment (MCI). Moreover, we discuss the challenges and issues associated with the application of NMR-based metabolomics in the context of AD research

    Habitat use and food habitats of a gecko population in a west African suburban area

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    1.The spatial and trophic ecology of Afrotropical gecko populations are poorly known. Here, we report ecological observations on Brook’s House Gecko (Hemidactylus angulatus), a widespread gekkonid species, in the Rivers State University of Science and Technology campus, Port Harcourt, Nigeria.2. A total of 488 gecko individuals were recorded during the present study, in two surveyed habitat types: (i) plantationm trees (PTH) and (ii) buildings (BDH). In PTH, they were observed in 13 out of 15 species of trees present in the study area, with their (log) frequency of sightings being positively correlated to the (log) frequency of surveyed trees per species.3. The geckos used substantially the non-native ornamental trees of the PTH habitat. Pinus ponderosa and Elaeis guineensis were significantly preferred by geckos over all the other tree species.4. Geckos also used frequently the buildings (BDH habitat) at the university campus. There was no correlation between (log) area of each building and (log) number of observed lizards.5. We collected faeces from 51 gecko individuals in dry season and 66 in wet season. There were no significant dietary differences between seasons, with Diptera and adult Lepidoptera dominating in the diet.6. Dietary habits of geckos differed significantly between habitat types, with Araneae and Lepidoptera (larvae) being eaten much more frequently in BDH, and in Coleoptera and Isopoda that were eaten much more frequently in PTH The diversity dietary metrics (Shannon and Dominance indices) were very similar either between seasons or between habitats.7. Our independent set of analyses (diet diversity metrics; contingency tables on taxonomic dietary composition and rank-abundance diagrams) showed that lizards exhibited a same feeding strategy in both wet and dry seasons as well as in the two habitat types, although the diet composition differed significantly between habitats.8. A “mixed” foraging strategy was apparently used by Hemidactylus angulatus at the study area, as also observed in other gekkonid species from elsewhere

    Assemblages d’oiseaux sur une plage sableuse méditerranéenne structuralement simplifiée : analyse spatio-temporelle

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    Studies on the bird richness and abundance patterning in sandy coastal areas are almost neglected. A better knowledge of bird assemblage structure could permit the developing of appropriate conservation strategies in these key ecosystems. In this study, we aimed to test the hypothesis that a patchy and structurally oversimplified ecosystem, as a Mediterranean sandy beach, may host bird assemblages highly variable in space and time and relatively poor in richness and abundance, whose structure should be therefore affected by chance. In 2007 a transect laid along a sandy beach was carried out, allowing to analyse the data temporally (six 2-month periods) and spatially (three longitudinal habitat types), either at single species or assemblage level. We observed a total of 25 bird species. Bird assemblages showed a taxonomical, phenological and ecological heterogeneity. In late autumn-winter the beach hosted the richest assemblage, in summer-autumn the lowest. Differences in mean values among 2-month periods were significant for species richness. Beaches represent patchy ecosystems with a different availability of resources in space and time. The presence of vegetation and linked trophic resources presumably permits the occurrence of a large variation in resource availability that determines a high turnover for different species along the temporal and spatial niche. Finally, we observed an inverse relationship between human presence and species richnessLes études des patterns de richesse et d'abondance spécifique sur les côtes sableuses sont quasi négligées. Une meilleure connaissance de la structure des assemblages d'oiseaux pourrait permettre le développement de stratégies de conservation appropriées dans ces écosystèmes-clés. Dans la présente étude, nous nous proposons de tester l'hypothèse qu'un écosystème aussi morcelé et structuralement aussi simplifié qu'une plage sableuse méditerranéenne pourrait abriter des assemblages d'oiseaux hautement variables dans le temps et dans l'espace et relativement pauvres en richesse et abondance, dont la structure serait donc affecté par le hasard. En 2007 un transect a été établi le long d'une plage sableuse afin d'analyser les données temporelles (six périodes de deux mois) et spatiales (trois types d'habitats longitudinaux) au niveau d'une espèce ou d'un assemblage. Nous avons observé un total de 25 espèces. Les assemblages d'oiseaux ont montré une hétérogénéité taxinomique, phénologique et écologique. La plage hébergeait l'assemblage le plus riche en fin d'automne-hiver, le plus pauvre en été-automne. Les valeurs moyennes de la richesse spécifique se sont avérées significativement différentes selon la période de deux mois. Les plages représentent des écosystèmes morcelés avec des disponibilités en ressources différentes dans le temps et dans l'espace. La présence de végétation et des ressources trophiques associées permet vraisemblablement une grande variation de la disponibilité des ressources qui détermine un fort renouvellement des diverses espèces le long de la niche spatio-temporelle. Enfin, nous avons observé une relation inverse entre la présence humaine et la richesse spécifique

    Age and Sex Effects on Plasma Metabolite Association Networks in Healthy Subjects

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    In the era of precision medicine, the analysis of simple information like sex and age can increase the potential to better diagnose and treat conditions that occur more frequently in one of the two sexes, present sex-specific symptoms and outcomes, or are characteristic of a specific age group. We present here a study of the association networks constructed from an array of 22 plasma metabolites measured on a cohort of 844 healthy blood donors. Through differential network analysis we show that specific association networks can be associated with sex and age: Different connectivity patterns were observed, suggesting sex-related variability in several metabolic pathways (branched-chain amino acids, ketone bodies, and propanoate metabolism). Reduction in metabolite hub connectivity was also found to be associated with age in both sex groups. Network analysis was complemented with standard univariate and multivariate statistical analysis that revealed age- and sex-specific metabolic signatures. Our results demonstrate that the characterization of metabolite-metabolite association networks is a promising and powerful tool to investigate the human phenotype at a molecular level

    Activité alimentaire et utilisation de l’espace dans une population naturalisée de Myiopsitta monachus dans une zone urbaine méditerranéenne

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    We studied a naturalized population of monk parakeet breeding in an urban park in Rome, by collecting data on the diurnal and feeding activity, space use (e.g, roosting preferences, flight height) and behavioural traits (e.g., cluster size). Consideration on the potential ecological impact of the species is also made. The diurnal activity of parakeets did not differ between morning and afternoon. Most individuals were observed in flight 6-10 m from the ground, and when at roost, parakeets preferred perch es higher than 5 m. The clusters sighted on ground were significantly larger in size than those observed on roosts, while cluster size was not linked to flight height. For this species, the observed roost preference indicates that the availability of perches on high trees seems to be an important factor for habitat selection: standing on trees may increase the chances to identify trophic resources, reduce the risk of predation when at rest, and prevent overheating from high summer temperatures during the day. Regarding to feeding habits, at our study site the monk parakeet fed on different plant species both on the trees and at the ground level (e.g., Fabaceae, Ulmaceae, Poaceae, Rosaceae), showing a clear preference towards some plant species, irrespective to their abundance, and with Scolymus hispanicus (Asteraceae) as the most exploited species by farNous avons étudié une population naturalisée de la perruche Myiopsitta monachus dans un parc urbain de Rome en recueillant des données sur les activités diurnes et de recherche de nourriture, de même que l'utilisation de l'espace (e.g. préférences pour les reposoirs, hauteur de vol) et les traits comportementaux (e.g. taille des regroupements). L'impact écologique potentiel de l'espèce a également été pris en considération. L'activité diurne des perruches ne montre aucune différence entre le matin et l'après-midi. La plupart des individus volent 6-10 m au-dessus du sol et, aux reposoirs ils préfèrent des perchoirs situés à plus de 5 m de hauteur. Les groupes étaient significativement plus grands au sol que dans les reposoirs tandis que leur taille n'était pas liée à la hauteur de vol. Les préférences observées quant aux reposoirs indiquent que la disponibilité de perchoirs dans de hauts arbres est, pour cette espèce, un facteur important du choix de l'habitat: une remise dans les arbres peut accroître les chances d'identifier des sources de nourriture, réduire les risques de prédation au repos et protéger des fortes chaleurs quand les températures diurnes estivales sont très élevées. En matière d'habitudes alimentaires, dans notre site d'étude, cette perruche se nourrissait de diverses espèces végétales tant sur les arbres qu'au sol (e.g. Fabacées, Ulmacées, Poacées, Rosacées), montrant une nette préférence pour quelques espèces quelle que soit leur abondance, Scolymus hispanicus (Astéracées) étant de loin la plus exploitée

    Semi-quantitative and qualitative evaluation of pial leptomeningeal collateral circulation in acute ischemic stroke of the anterior circulation: the Careggi Collateral Score

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    Introduction: The imaging of ischemic penumbra in acute stroke is a debated issue and establishing commonly accepted criteria is difficult. Computerized tomography-perfusion studies conducted in animals have showed that the modifications occurring in the brain parenchima are part of a dynamic and progressive process involving the microcirculation. The purpose of this paper is to propose a new angiographic classification of collateral circulation in patients with acute ischemic stroke, with a possible correlation with the clinical outcome. Materials and methods: The basal angiograms of 57 patients with acute ischemic stroke is the territory of anterior circulation secondary to a major occlusion, who underwent endovascular treatment, were retrospectively reviewed and collaterals were classified according to our novel Careggi Collateral Score in 6 grades (0-6). The clinical outcome after 3 months was evaluated with modified Rankin Scale. A ROC (receiver operating characteristic) curve analysis identified a cut-off value of 1. Results: Patients with favorable collateral circulation (grades 2-5) showed a significant correlation with good clinical outcome (modified Rankin Scale ≤2). Conclusions: The Careggi Collateral Score resulted a useful tool to evaluate the chance of obtaining a favorable result with endovascular treatment in patients with acute ischemic stroke in the anterior circulation secondary to the occlusion of a major artery

    KODAMA exploratory analysis in metabolic phenotyping

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    KODAMA is a valuable tool in metabolomics research to perform exploratory analysis. The advanced analytical technologies commonly used for metabolic phenotyping, mass spectrometry, and nuclear magnetic resonance spectroscopy push out a bunch of high-dimensional data. These complex datasets necessitate tailored statistical analysis able to highlight potentially interesting patterns from a noisy background. Hence, the visualization of metabolomics data for exploratory analysis revolves around dimensionality reduction. KODAMA excels at revealing local structures in high-dimensional data, such as metabolomics data. KODAMA has a high capacity to detect different underlying relationships in experimental datasets and correlate extracted features with accompanying metadata. Here, we describe the main application of KODAMA exploratory analysis in metabolomics research
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