1,521 research outputs found
Alle radici della mentalità tecnologica: L'uomo tolemaico di Sergio Cotta.
Veinticinco aitos despues de su publicacion, se analiza en profundidad
el texto de Sergio Cotta, L'uomo tolemaico, hasta llegar a la conclusion de
que resulta plenamente actual. Y en efecto, el subjetivismo, la hipertrofia del yo
-raices ultimas de la sociedad tecnologica, en el diagnostico/denuncia de Cotta-,
parecen haberse difimdido y radicalizado en nuestros dias. Tal estado de cosas
exige una radical y autentica metanoia: no es la ciencia la que redime al
hombre, sino solo el amor; un amor incondicionado y no sometido a la muerte
Amphibian Biology. Volume 11, Part 4: Status of Conservation and Decline of Amphibians: Eastern Hemisphere. Southern Europe and Turkey
Heatwole, H. and J. W. Wilkinson (eds.). 2015. Amphibian Biology. Volume 11, Part 4: Status of Conservation and Decline of Amphibians: Eastern Hemisphere. Southern Europe and Turkey. 158 pp. Pelagic Publishing, Exeter, UK
Thirty years of invasion: the distribution of the invasive crayfish Procambarus clarkii in Italy
The presence of the red swamp crayfish Procambarus clarkii in Italy is documented since 1989, but no comprehensive data are available on its spread through time at the national scale. New confirmed records for Procambarus clarkii are continuously arising in recent years across the country. By reviewing the scientific and grey literature, we obtained an up-to-date map of the species invasion in Italy. This information can help to monitor and understand the spread of this highly invasive crayfish and to implement more effective management measures.
Numerical methods for sedimentary‐ancient‐DNA‐based study on past biodiversity and ecosystem functioning
Abstract Sedimentary ancient DNA (SedaDNA) is an emerging tool to reconstruct past biodiversity with high taxonomic resolution. Its growing popularity has stimulated an increasing complexity of SedaDNA data production (e.g., DNA extraction, amplification, and sequencing; authentication of molecules; bioinformatics). Conversely, less attention has been devoted to how appropriate statistical analyses can help to extract ecological information from SedaDNA. Until now, ecological studies based on SedaDNA have taken limited advantage of the multiple statistical and numerical methods available for analysis. Here, we present a range of numerical approaches that can be particularly useful to multispecies ecological analysis on SedaDNA, with a special focus on biodiversity studies on macroorganisms. We discuss the advantages and complexity of such methods and describe how some of them can be optimized for ecological analyses of SedaDNA‐based metabarcoding data, with a special focus on SedaDNA studies. First, site occupancy‐detection models can help to better ascertain the variation through time of the occurrence of target species and to identify the factors determining their detection through time. Second, several approaches can be used to estimate variation of relative abundance. Even though methods for abundance estimation have major limitations, they can provide useful information on temporal variation of ecosystem functions. Third, approaches exist to obtain better measures of species diversity, while taking into account the uncertainties of species abundance and identification. Fourth, techniques of clustering, ordination, and constrained ordination allow identification of temporal trends and testing of candidate drivers of community variation. Finally, structural equation models can be used to assess complex causal relationships among biodiversity, human activities, and environment. SedaDNA studies can make use of a broad panel of analytical approaches, which can improve our understanding of long‐term biodiversity changes, maximizing the information we can obtain from past ecosystems
Supernova neutrino physics with a nuclear emulsion detector
The existence of the coherent neutrino-nucleus scattering reaction requires
to evaluate, for any detector devoted to WIMP searches, the irreducible
background due to conventional neutrino sources and at same time, it gives a
unique chance to reveal supernova neutrinos. We report here a detailed study
concerning a new directional detector, based on the nuclear emulsion
technology. A Likelihood Ratio test shows that, in the first years of
operations and with a detector mass of several tens of tons, the observation of
the supernova signal can be achieved. The determination of the distance of the
supernova from the neutrinos and the observation of B neutrinos are also
discussed.Comment: 22 pages, 12 figure
The transport of nanoparticles in blood vessels: the effect of vessel permeability and blood rheology
The longitudinal transport of nanoparticles in blood vessels has been analyzed with blood described as a Casson fluid. Starting from the celebrated Taylor and Aris theory, an explicit expression has been derived for the effective longitudinal diffusion (Deff) depending non-linearly on the rheological parameter xi(c), the ratio between the plug and the vessel radii; and on the permeability parameters pi and omega, related to the hydraulic conductivity and pressure drop across the vessel wall, respectively. An increase of xi(c) or pi has the effect of reducing Deff, and thus both the rheology of blood and the permeability of the vessels may constitute a physiological barrier to the intravascular delivery of nanoparticles
Switching from mesopredator to apex predator: how do responses vary in amphibians adapted to cave living?
AbstractThe effective detection of both prey and predators is pivotal for the survival of mesopredators. However, the condition of being a mesopredator is strongly context dependent. Here we focus on two aquatic caudate species that have colonised caves: the Pyrenean newt (Calotriton asper) and the olm (Proteus anguinus). The former maintains both surface and subterranean populations, while only cave-adapted populations of the latter exist. Both species are apex predators in underground waterbodies, while the Pyrenean newt is a mesopredator in surface waterbodies. Shifting to a higher level of the trophic web through colonising caves may promote the loss of anti-predator response against surface apex predators, and an increase in the ability to detect prey. To test these two non-exclusive hypotheses, we integrated classical behavioural characterisations with a novel approach: the assessment of lateralisation (i.e. preference for one body side exposure). Behavioural experiments were performed using laboratory-reared individuals. We performed 684 trials on 39 Pyrenean newts and eight olms. Under darkness and light conditions, we tested how exposure to different chemical cues (predatory fish, prey and unknown scent) affected individuals' activity and lateralisation. Both cave and surface Pyrenean newts responded to predator cues, while olms did not. In Pyrenean newts, predator cues reduced the time spent in movement and time spent in lateralisation associated with hunting. Our results show that predator recognition is maintained in a species where recently separated populations inhabit environments lacking of higher predators, while such behaviour tends to be lost in populations with longer history of adaptation.Significance statementPredator recognition can be maintained in animals adapted to predator free habitats, but varies with their history of adaptation. Species that are not at the apex of the food web can become top predators if they colonise subterranean environments. We compared the behavioural responses of the olm, a strictly cave species with a long underground evolutionary history, and of the Pyrenean newt, a facultative cave species that also has stream-dwelling populations. Moreover, we integrated a classical behavioural characterisation, such as movement detection, with a novel approach: the assessment of lateralisation. While olms do not respond to external predators scent, cave-dwelling newts still recognise it. This clearly indicates that predator recognition is still maintained in species that have colonised predator-free environments more recently
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