1,553 research outputs found
Podarcis siculus latastei (Bedriaga, 1879) of the western pontine islands (italy) raised to the species rank, and a brief taxonomic overview of podarcis lizards
In recent years, great attention has been paid to many Podarcis species for which the observed intra-specific variability often revealed species complexes still characterized by an unresolved relationship. When compared to other species, P. siculus underwent fewer revisions and the number of species hidden within this taxon may have been, therefore, underestimated. However, recent studies based on genetic and morphological data highlighted a marked differentiation of the populations inhabiting the Western Pontine Archipelago. In the present work we used published genetic data (three mitochondrial and three nuclear gene fragments) from 25 Podarcis species to provide a multilocus phylogeny of the genus in order to understand the degree of differentiation of the Western Pontine populations. In addition, we analyzed new morphometric traits (scale counts) of 151 specimens from the main islands of the Pontine Archipelago. The phylogenetic analysis revealed five principal Podarcis groups with biogeographic consistency. The genetic distinctiveness of the Podarcis populations of the Western Pontine Islands is similar or even more ancient than those observed in numerous other pairs of Podarcis sister species. In the light of these evidences we raise the Western Pontine lizards to specific rank; thus they should be referred to as Podarcis latastei
Attenuating heat stress through green roof and green wall retrofit
© 2018 Elsevier Ltd The process of rapid urbanisation is becoming problematic due to the reduction in, and lack of compensation of, previously vegetated areas. With a combination of green roofs and green walls, adopted on a large scale, it is possible to attenuate the urban heat island effect and internal temperatures in buildings. Tall buildings are becoming a common housing type in many cities, and considering the role of external walls in heat gain, it is expected that the combination of green roofs and green walls have great potential to improve thermal performance. As only 1-2% is added to the total stock of buildings annually, the focus should be on the retrofit of existing buildings to deliver maximum thermal benefits. In the present work lightweight, modular vegetated systems were adopted for roofs and walls. Instead of considering only the temperature influence in heat stress, this research adopted the use of heat index that encompasses the combined effect of temperature and relative humidity. For this purpose, the thermal benefits of green roof and green wall retrofit is evaluated in two small scale experiments, where identical prototypes (vegetated and non-vegetated) are compared using block work and timber framed drywall structures for Rio de Janeiro, Brazil and Sydney, Australia, respectively. The results show a different understanding in heat stress evaluation regarding heat index rather than temperature itself, especially under high levels of relative humidity. This evidence demonstrates green roof and green wall retrofit offer a proven role in heat stress attenuation in residential buildings
Modelling green roof stormwater response for different soil depths
© 2016 Elsevier B.V. Green roofs have been proposed as a way to mitigate stormwater run-off in urban areas due to the possibility of retrofit to existing buildings. The amount of run-off is influenced by the, humidity, evapotranspiration, as well as soil type and depth. A modelling approach was undertaken to evaluate the response of different soil depths to cumulative rainfall and the efficiency in stormwater flow rate attenuation. The soil hydraulics were modelled using HYDRUS-1D software developed for modelling water flow in variably saturated porous media. Model runs were carried out for three quarterly scenarios to determine run-off peak flow rates and the overall retention, based on evapotranspiration rates of succulent plants and rainfall registers from Auckland, New Zealand. The soil depths modelled ranged from 5 to 160 cm. The efficiencies in peak flow attenuation by the shallowest soil considered were reduced under extreme and longer rainfall events by 3%. Therefore shallow soil or extensive green roofs may, on a wide scale, overcome the performance of deep soils due to their lighter weight which adds limited loads to existing roof structures thereby making them suited to retrofit greater numbers of buildings
Cryptic speciation and chromosomal repatterning in the South African climbing mice Dendromus (Rodentia, Nesomyidae)
We evaluate the intra- and interspecific diversity in the four South African rodent species of the genus Dendromus. The molecular phylogenetic analysis on twenty-three individuals have been conducted on a combined dataset of nuclear and mitochondrial markers. Moreover, the extent and processes underlying chromosomal variation, have been investigated on three species by mean of G-, C-bands, NORs and Zoo-FISH analysis. The molecular analysis shows the presence of six monophyletic lineages corresponding to D. mesomelas, D. mystacalis and four lineages within D. cfr. melanotis with high divergence values (ranges: 10.6% – 18.3%) that raises the question of the possible presence of cryptic species. The first description of the karyotype for D. mesomelas and D. mystacalis and C- and G- banding for one lineage of D. cfr. melanotis are reported highlighting an extended karyotype reorganization in the genus. Furthermore, the G-banding and Zoo-FISH evidenced an autosome-sex chromosome translocation characterizing all the species and our timing estimates this mutation date back 7.4 mya (Late Miocene). Finally, the molecular clock suggests that cladogenesis took place since the end of Miocene to Plio-Pleistocene, probably due to ecological factors, isolation in refugia followed by differential adaptation to the mesic or dry habitat
In "defense" of Podarcis latastei, an Italian insular endemic species (Squamata: Lacertidae)
Based on genetic and morphological evidence, Senczuk et al. (2019) formally raised the Podarcis populations from the Western Pontine Islands, previously classified as several subspecies of P. siculus, to species rank, i.e. Podarcis latastei (Bedriaga, 1879). This taxonomic change was not accepted in the checklist of the European herpetofauna by Speybroeck et al. (2020), recently published on Amphibia-Reptilia. In this note we respond to the reasons given by Speybroeck and colleagues and support the validity of Podarcis latastei as an endemic Italian species
The evolutionary history of a mammal species with a highly fragmented range: the phylogeography of the European snow vole.
The European snow vole Chionomys nivalis has a patchy distribution restricted to
rocky habitats across southern Europe and the Near and Middle East. We carried
out a phylogeographic study to provide a biogeographic scenario, based on
molecular data, outlining the major processes that determined the current
distribution of the species. The samples include 26 snow voles from 14 different
populations across the entire species range from Spain to Anatolia and Israel.
Nearly complete sequences (1037 bp) of the mitochondrial gene for cytochrome b
were sequenced. Relationships among haplotypes were inferred with neighbourjoining,
maximum likelihood, maximum parsimony analyses and minimum spanning
network. An analysis of mismatch distribution was used to cast light on past
demographic expansion. We found 22 different haplotypes that fall into six distinct
lineages, all but one is supported by high bootstrap values with all methods. Four
lineages are allopatric (Tatra Mts., Iberia, Balkans and Middle East) while
divergent haplotypes from two lineages show sympatry in the Alps and the
Apennines. The basal relationships of these lineages could not be established by
any tree. The mean pairwise genetic distance between lineages ranges from 2.4 to
4.2%. The shape of the mismatch distribution indicated a past expansion event
dating back to between 158 000 and 84 000 years ago. These data can be interpreted
with the existence of southern glacial refugia (Iberia, Balkans, Middle East and
Italy) and one additional northern glacial refugium. The lack of phylogenetic
resolution among lineages and the shape of mismatch distribution are indicative of
a simultaneous and rapid splitting due to a relatively fast initial expansion of
populations. Moreover, the analysis supports the hypothesis of the European
origin of C. nivalis and its subsequent eastward dispersion during the Middle
Pleistocene
Trapped in the morphospace: The relationship between morphological integration and functional performance
The evolution of complex morphological structures can be characterized by the interplay between different anatomical regions evolving under functional integration in response to shared selective pressures. Using the highly derived humeral morphology of talpid moles as a model, here we test whether functional performance is linked to increased levels of evolutionary integration between humerus subunits and, if so, what the strength is of the relationship. Combining two-dimensional geometric morphometrics, phylogenetic comparative methods, and functional landscape modeling, we demonstrate that the high biomechanical performance of subterranean moles’ humeri is coupled with elevated levels of integration, whereas taxa with low-performance values show intermediate or low integration. Theoretical morphs occurring in high-performance areas of the functional landscape are not occupied by any species, and show a marked drop in covariation levels, suggesting the existence of a strong relationship between integration and performance in the evolution of talpid moles’ humeri. We argue that the relative temporal invariance of the subterranean environment may have contributed to stabilize humeral morphology, trapping subterranean moles in a narrow region of the landscape and impeding any attempt to reposition on a new ascending slope
Population genetic structure of the bank vole Myodes glareolus within its glacial refugium in peninsular Italy
A Hybrid Storage Systems for All Electric Aircraft
A hybrid energy storage system specifically designed for a fully electric aircraft is presented in the paper. The analysis of the time evolution of the power demand of the electric propulsion system during a test mission of Maxwell X-57, an all-electric aircraft developed by NASA, has pointed out the presence of significant peak power during take-off and air tack. Considered the issues related to weight and the volume of the energy storage systems (ESSs) in all-electric aircraft, a hybridization of aircraft ESS with a Supercapacitors (SCs) bank, devoted to smooth peak power demand, has been investigated. A comparison between the simulation results of an electrochemical battery and hybrid ESSs, designed on the test mission of Maxwell X-57 power demand, has been developed. The advantage of hybrid configuration with respect to battery-based one in term of volume and weight reduction is finally presented
Experimental study on B-spline-based modulation schemes applied in multilevel inverters for electric drive applications
This work presents the design, simulation, and experimental validation of new B-Spline-based modulation techniques applied to a Multilevel Power Inverter (MPI), particularly focusing the attention on the harmonic content of the output voltages of the inverter. Simulation and experimental results are proposed and discussed, mainly describing the potential benefits, such as the increase of the multi-level operation of the converter, and drawbacks (low-order harmonics) related to the adoption of B-Spline functions for multilevel inverters applied in the field of electrical drives
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