7,372 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
Heidegger, intérprete de San Agustín: el tiempo, nuevas fuentes para la recepción heideggeriana de las Confesiones de San Agustín
Based on new textual resources, the article reconstructs and analyses St. Augustine’s interpretation of time made by Heidegger. Two moments are to be distinguished: Whereas the first one is basically critical and epitomizes the Augustinian analysis as an analysis of “vulgar time”, the second one reconsiders this judgement. This result is more accurate but also more condescendential with Heidegger’s own approach on time. However, it distorts some Augustinian concepts, which are reviewed in detail
Reptile assemblages across agricultural landscapes: where does biodiversity hide?
Comunidades de reptiles en paisajes agrícolas: ¿dónde se esconde la biodiversidad?La transición de la agricultura tradicional a la intensiva, orientada a la producción a gran escala, ha alterado rápidamente los paisajes agrícolas, lo que ha conllevado la reducción y fragmentación de los hábitats naturales y la consiguiente pérdida de biodiversidad. La herpetofauna está gravemente amenazada por la intensificación agrícola en todo el mundo, pero se sabe poco acerca de su distribución en los ecosistemas agrícolas, especialmente a escala local. Se analizaron la abundancia y la diversidad de reptiles en ocho usos del suelo agrícolas y seminaturales, así como dentro de parches de vegetación intercalados entre cultivos. Curiosamente, la mayoría de los reptiles se observó en los parches de vegetación, mientras que en los cultivos intensivos y los pastos solo se encontró una especie de lagarto. La riqueza de individuos y de especies aumenta cuando los parches de vegetación están en contacto con zonas seminaturales, independientemente de la anchura y la estructura de la vegetación de estas. En vista de los resultados obtenidos, que ponen de relieve la influencia de las características del paisaje de menor importancia en la presencia de vertebrados en los ecosistemas agrícolas intensivos, recomendamos incluir parches de vegetación como medida de conservación de los vertebrados en los paisajes agrícolas.The transition from traditional to intensive farming, aimed at large–scale production, has rapidly altered agricultural landscapes, leading to the reduction and fragmentation of natural habitats and to the consequent loss of biodiversity. Herpetofauna is seriously threatened by agriculture intensification worldwide, but less is known about its distribution in agro–ecosystems, especially at field scale. We analysed reptile abundance and diversity in eight agricultural and semi–natural land uses, and inside vegetated buffer strips interspersed among fields. Interestingly, most reptiles were recorded in the buffer strips while intensive crops and pastures hosted just one lizard species. Richness of individuals and species increased when strips were connected to semi–natural areas, independently of their width and vegetation structure. In view of our results, that highlight the role of minor landscape features for the presence of vertebrates in intensive agro–ecosystems, we recommend the implementation of buffer strips among the measures for vertebrate conservation in agricultural landscapes.Comunidades de reptiles en paisajes agrícolas: ¿dónde se esconde la biodiversidad?La transición de la agricultura tradicional a la intensiva, orientada a la producción a gran escala, ha alterado rápidamente los paisajes agrícolas, lo que ha conllevado la reducción y fragmentación de los hábitats naturales y la consiguiente pérdida de biodiversidad. La herpetofauna está gravemente amenazada por la intensificación agrícola en todo el mundo, pero se sabe poco acerca de su distribución en los ecosistemas agrícolas, especialmente a escala local. Se analizaron la abundancia y la diversidad de reptiles en ocho usos del suelo agrícolas y seminaturales, así como dentro de parches de vegetación intercalados entre cultivos. Curiosamente, la mayoría de los reptiles se observó en los parches de vegetación, mientras que en los cultivos intensivos y los pastos solo se encontró una especie de lagarto. La riqueza de individuos y de especies aumenta cuando los parches de vegetación están en contacto con zonas seminaturales, independientemente de la anchura y la estructura de la vegetación de estas. En vista de los resultados obtenidos, que ponen de relieve la influencia de las características del paisaje de menor importancia en la presencia de vertebrados en los ecosistemas agrícolas intensivos, recomendamos incluir parches de vegetación como medida de conservación de los vertebrados en los paisajes agrícolas
Experimental determination of the frequency and field dependence of Specific Loss Power in Magnetic Fluid Hyperthermia
Magnetic nanoparticles are promising systems for biomedical applications and
in particular for Magnetic Fluid Hyperthermia, a promising therapy that
utilizes the heat released by such systems to damage tumor cells. We present an
experimental study of the physical properties that influences the capability of
heat release, i.e. the Specific Loss Power, SLP, of three biocompatible
ferrofluid samples having a magnetic core of maghemite with different core
diameter d= 10.2, 14.6 and 19.7 nm. The SLP was measured as a function of
frequency f and intensity of the applied alternating magnetic field H, and it
turned out to depend on the core diameter, as expected. The results allowed us
to highlight experimentally that the physical mechanism responsible for the
heating is size-dependent and to establish, at applied constant frequency, the
phenomenological functional relationship SLP=cH^x, with 2<x<3 for all samples.
The x-value depends on sample size and field frequency/ intensity, here chosen
in the typical range of operating magnetic hyperthermia devices. For the
smallest sample, the effective relaxation time Teff=19.5 ns obtained from SLP
data is in agreement with the value estimated from magnetization data, thus
confirming the validity of the Linear Response Theory model for this system at
properly chosen field intensity and frequency
Photometric and spectroscopic variations of the Be star HD 112999
Be objects are stars of B spectral type showing lines of the Balmer series in
emission. The presence of these lines is attributed to the existence of an
extended envelope, disk type, around them. Some stars are observed in both the
Be and normal B-type spectroscopic states and they are known as transient Be
stars. In this paper we show the analysis carried out on a new possible
transient Be star, labelled HD 112999, using spectroscopic optical observations
and photometric data.Comment: 10 pages, 5 figures, accepted for publication in IBV
Near-infrared spectroscopy study of tourniquet-induced forearm ischaemia in patients with coronary artery disease
Near-Infrared Spectroscopy (NIR) can be employed to monitor local changes in haemodynamics and oxygenation of human tissues. A preliminary study has been performed in order to evaluate the NIRS transmittance response to induced forearm ischaemia in patients with coronary artery disease (CAD). The population consists in 40 patients with cardiovascular risk factors and angiographically documented CAD, compared to a group of 13 normal subjects. By inflating and subsequently deflating a cuff placed around the patient arm, an ischaemia has been induced and released, and the patients have been observed until recovery of the basal conditions. A custom LAIRS spectrometer (IRIS) has been used to collect the backscattered light intensities from the patient forearm throughout the ischaemic and the recovery phase. The time dependence of the near-infrared transmittance on the control group is consistent with the available literature. On the contrary, the magnitude and dynamics of the NIRS signal on the CAD patients show deviations from the documented normal behavior, which can be tentatively attributed to abnormal vessel stiffness. These preliminary results, while validating the performance of the IRIS spectrometer, are strongly conducive towards the applicability of the NIRS technique to ischaemia analysis and to endothelial dysfunction characterization in CAD patients with cardiovascular risk factors.Publisher PD
Crayfish predation on tadpoles: a comparison between a native (Austropotamobius pallipes) and an alien species (Procambarus clarkii).
Transcriptional activators and repressors for the neuron-specific expression of a metabotropic glutamate receptor
Metabotropic glutamate receptor 1 (mGlu1) has a discrete distribution in the central nervous system restricted to neurons. Its expression undergoes important changes during development and in response to physiological and pathological modifications. Here, we have determined the structure of the mGlu1 gene and demonstrated that mGlu1 transcription takes places at alternative first exons. Moreover, we have identified active promoter regions upstream from the two most expressed first exons by means of luciferase reporter gene assays performed in primary cerebellar granule neurons. Targeted mutations of active elements constituting the core promoter and electrophoretic mobility shift assays demonstrated that the factors thyroid transcription factor-1 and CCAAT/enhancer-binding proteins β act synergistically to promote mGlu1 transcription. We have also elucidated the molecular bases for the neuron-specific expression of mGlu1 identifying a neural restrictive silencing element and a regulatory factor for X box element, which suppressed mGlu1 expression in nonneuronal cells. These results reveal the molecular bases for cell- and context-specific expression of an important glutamate receptor critically involved in synaptogenesis, neuronal differentiation, synaptic transmission, and plasticity. © 2007 by The American Society for Biochemistry and Molecular Biology, Inc
Convective heat transfer CFD analysis of forced flow through a half-stadium serpentine mini-channel at low Reynolds number
- …