7 research outputs found
Population Viability Analysis su Lepus corsicanus nel Parco Nazionale del Cilento e Vallo di Diano
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Population Viability Analysis and genetic features in lepus corsicanus and L. europaeus living simpatrically
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Landscape fragmentation and habitat suitability in endangered Italian hare (Lepus corsicanus) and European hare (Lepus europaeus) populations
No full textDuring the last years, the population of Italian hare decreased significantly in central and south Italy. This is imputable to harvest, poaching, habitat fragmentation, and the probable competition with congeneric European hare introduced in the last decades by man for hunt. The goal of our work is to define the ecological characteristics of the two aforementioned species in order to understand how landscape facilitates or impedes movement. Spatially explicit models are used to identify a species ecological niche and to build a landscape model of suitability. To validate ecological modeling of landscape, we performed a population genetic analysis. Results suggest that the Italian hare shows an ecological requirement close to average of available resources in the considered landscape. The genetic structure of this autochthonous species validates the habitat suitability model and highlights the differences with European hare. This work analyzes for the first time the ecological relationship between those two sympatric species
Where do Sardinia orchids come from: a putative African origin for the insular population of Platanthera bifolia var. kuenkelei?
No full textBecause of the complex geoclimatic dynamics of the Mediterranean basin, resulting from a combination of Tertiary geological processes and Quaternary climatic oscillations, the current species composition of the main continental islands is a mosaic resulting from relative contribution of vicariance, geodispersal and long-distance dispersal by seed. To help distinguish among the contributions of these different dispersal modes to the orchid species richness on the island of Sardinia, we investigated the genetic structure and phylogeographic relationship of the only Platanthera bifolia var. kuenkelei population on the island. By using plastid DNA sequence variation, we show that this recently discovered population is more closely related to the Tunisian P. bifolia var. kuenkelei than to the geographically closer P. bifolia populations from peninsular Italy. Results from haplotype network construction support the hypothesis that the current distribution of P. bifolia var. kuenkelei (Sardinia and Tunisia) is most likely explained by over-sea dispersal. However, haplotype diversity and mismatch analysis of this unique Sardinian population suggest that, if a long-distance dispersal event did occur, it was not recent. More likely, temporarily favourable climatic conditions generated a suitable habitat on the island (also in terms of suitable mycorrhizas and pollinators) and thus a transient opportunity for seedling growth and population establishment of P. bifolia var. kuenkelei from North Africa
Role of the insulating fillers in the encapsulation material on the lateral charge spreading in HV-ICs
No full textHigh electric fields and temperatures in high-voltage ICs (HV-ICs) can induce charge transport phenomena in the encapsulation material leading to reliability test failures. In this paper, the resistivity of epoxy-based resins with insulating microfiller weight fraction exceeding 70% has been experimentally and theoretically investigated for the first time. Electrical conductivity has been measured at high temperature (150 °C) using both dielectric spectroscopy analysis on bulk samples and charge-spreading characterizations on a dedicated test chip with integrated charge sensors. The use of a charge sensor close to the internal HV metallization leads to results more pertinent with the active area of HV-ICs. Remarkably, both experiments show an unexpected increase and a significant variability of the electrical conductivity as the microfiller fraction is increased. The strong correlation between bulk and lateral experiments clearly indicates that those features should be attributed to the bulk material. Numerical simulations of diffusion phenomenon in mold structures with random arrangements of spherical microfillers demonstrate that the conductivity increase with filler content can be ascribed to the role of the epoxy/filler interfaces
