3,253 research outputs found

    Updating known distribution models for forecasting climate change impact on endangered species

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    To plan endangered species conservation and to design adequate management programmes, it is necessary to predict their distributional response to climate change, especially under the current situation of rapid change. However, these predictions are customarily done by relating de novo the distribution of the species with climatic conditions with no regard of previously available knowledge about the factors affecting the species distribution. We propose to take advantage of known species distribution models, but proceeding to update them with the variables yielded by climatic models before projecting them to the future. To exemplify our proposal, the availability of suitable habitat across Spain for the endangered Bonelli’s Eagle (Aquila fasciata) was modelled by updating a pre-existing model based on current climate and topography to a combination of different general circulation models and Special Report on Emissions Scenarios. Our results suggested that the main threat for this endangered species would not be climate change, since all forecasting models show that its distribution will be maintained and increased in mainland Spain for all the XXI century. We remark on the importance of linking conservation biology with distribution modelling by updating existing models, frequently available for endangered species, considering all the known factors conditioning the species’ distribution, instead of building new models that are based on climate change variables only.Ministerio de Ciencia e Innovación and FEDER (project CGL2009-11316/BOS

    El concepto jurídico de la sangre y sus derivados desde la perspectiva del derecho comunitario y español

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    El presente trabajo pretende analizar desde el punto de vista del Derecho farmacéutico el concepto jurídico dela sangre y sus derivados, concepto que ha de servirnos para valorar la situación de la sangre y los hemoderivadosy su inclusión o no dentro de la normativa existente para los medicamentos de uso humano. Para conseguirestablecer unos criterios adecuados sobre esta cuestión, en primer lugar hemos de definir el concepto jurídico demedicamento, que no parece claro, a pesar de las distintas definiciones que aporta la legislación. Estas definiciones,en ocasiones pueden parecer ambiguas y presentar zonas fronterizas no definidas que necesitan de un nuevoavance que consiga reflejar con claridad el concepto jurídico de medicamento. Para conseguir determinar conmayor precisión el concepto de medicamento hemos de utilizar de forma reiterada las diversas sentencias queaporta la jurisprudencia comunitaria en la materia, que ha debido de interpretar y aclarar en más de una ocasiónla indefinición que presenta la normativa para determinar de forma clara y meridiana el concepto de medicamento.Una vez definido el concepto de medicamento, pretendemos observar cómo quedan incorporados a esta definiciónlos medicamentos derivados de la sangre y plasma humanos, así como las zonas fronterizas que este tipode medicamentos presentan

    Suitability of salivary leucocytes to assess DNA repair ability in human biomonitoring studies by the challenge-comet assay

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    The challenge-comet assay is a simple but effective approach that provides a quantitative and functional determination of DNA repair ability, and allows to monitor the kinetics of repair process. Peripheral blood mononuclear cells (PBMC) are the cells most frequently employed in human biomonitoring studies using the challenge-comet assay, but having a validated alternative of non-invasive biomatrix would be highly convenient for certain population groups and circumstances. The objective of this study was to validate the use of salivary leucocytes in the challenge-comet assay. Leucocytes were isolated from saliva samples and challenged (either in fresh or after cryopreservation) with three genotoxic agents acting by different action mechanisms: bleomycin, methyl methanesulfonate, and ultraviolet radiation. Comet assay was performed just after treatment and at other three additional time points, in order to study repair kinetics. The results obtained demonstrated that saliva leucocytes were as suitable as PBMC for assessing DNA damage of different nature that was efficiently repaired over the evaluated time points, even after 5 months of cryopreservation (after a 24 h stimulation with PHA). Furthermore, a new parameter to determine the efficacy of the repair process, independent of the initial amount of damage induced, is proposed, and recommendations to perform the challenge-comet assay with salivary leucocytes depending on the type of DNA repair to be assessed are suggested. Validation studies are needed to verify whether the method is reproducible and results reliable and comparable among laboratories and studies. © 2022 The AuthorsFunding text 1: This work was funded by the Spanish Ministry of Science and Innovation : MCIN/AEI/10.13039/501100011033 (Grants PID2020-113788RB-I00 and PID2020-114908 GA-I00 ), NanoBioBarriers project (PTDC/MED-TOX/31162/2017), Xunta de Galicia (ED431B 2022/16), co-financed by the Operational Program for Competitiveness and Internationalization (POCI) through European Regional Development Funds ( FEDER / FNR ), Spanish Ministry of Education, Culture and Sport [ BEAGAL18/00142 to V.V.], and Spanish Ministry of Economy and Competitiveness , co-financed by the European Social Fund [ RYC-2015-18394 to L.L,-L,]. Funding for open access charge: Universidade da Coruña/CISUG. ; Funding text 2: This work was funded by the Spanish Ministry of Science and Innovation: MCIN/AEI/10.13039/501100011033 (Grants PID2020-113788RB-I00 and PID2020-114908 GA-I00), NanoBioBarriers project (PTDC/MED-TOX/31162/2017), Xunta de Galicia (ED431B 2022/16), co-financed by the Operational Program for Competitiveness and Internationalization (POCI) through European Regional Development Funds (FEDER/FNR), Spanish Ministry of Education, Culture and Sport [BEAGAL18/00142 to V.V.], and Spanish Ministry of Economy and Competitiveness, co-financed by the European Social Fund [RYC-2015-18394 to L.L,-L,]. Funding for open access charge: Universidade da Coruña/CISUG

    Effect of ZrO2 nanoparticles on thermophysical and rheological properties of three synthetic oils

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    This article presents an experimental study on some thermophysical properties (density, viscosity and adiabatic bulk modulus) of six nanolubricants based on synthetic oils and ZrO2 nanoparticles. Two-step method with ultrasonic disruptor was used to prepare the nanodispersions. The morphology, crystalline degree and elemental composition of nanoparticles were analyzed by electron microscopy. Visual observation, temporal variation of refractive index and dynamic light scattering were used to analyze the stability of the nanolubricants and the average size of the aggregates. The presence of new interactions between nanoparticles and base oils was studied through Fourier transform infrared spectrometer. Vibrating tube densimeters, rotational viscometer and rheometer equipped with cone-plate geometry were used within the temperature range from (278.15 to 373.15) K. The ability of some theoretical simple models to predict densities and viscosities of these nanolubricants as a function of temperature and nanoparticle concentration was also checked.This work was supported by Spanish Ministry of Economy and Competitiveness and the UE FEDER programme through ENE2014-55489-C2-1-R, ENE2014-55489-C2-2-R, ENE2017-86425- C2-1-R and ENE2017-86425-C2-2-R projects. Moreover, this work was funded by the Xunta de Galicia (AGRUP2015/11 and GRC ED431C 2016/001). D.C. was recipient of a postdoctoral fellowship from Xunta de Galicia (Spain).S

    Singularities and Topology of Meromorphic Functions

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    We present several aspects of the "topology of meromorphic functions", which we conceive as a general theory which includes the topology of holomorphic functions, the topology of pencils on quasi-projective spaces and the topology of polynomial functions.Comment: 21 pages, 1 figur

    Seropositivity and Risk Factors Associated with Toxoplasma gondii Infection in Wild Birds from Spain

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    Toxoplasma gondii is a zoonotic intracellular protozoan parasite of worldwide distribution that infects many species of warm-blooded animals, including birds. To date, there is scant information about the seropositivity of T. gondii and the risk factors associated with T. gondii infection in wild bird populations. In the present study, T. gondii infection was evaluated on sera obtained from 1079 wild birds belonging to 56 species (including Falconiformes (n = 610), Strigiformes (n = 260), Ciconiiformes (n = 156), Gruiformes (n = 21), and other orders (n = 32), from different areas of Spain. Antibodies to T. gondii (modified agglutination test, MAT titer ≥1∶25) were found in 282 (26.1%, IC95%:23.5–28.7) of the 1079 birds. This study constitute the first extensive survey in wild birds species in Spain and reports for the first time T. gondii antibodies in the griffon vulture (Gyps fulvus), short-toed snake-eagle (Circaetus gallicus), Bonelli's eagle (Aquila fasciata), golden eagle (Aquila chrysaetos), bearded vulture (Gypaetus barbatus), osprey (Pandion haliaetus), Montagu's harrier (Circus pygargus), Western marsh-harrier (Circus aeruginosus), peregrine falcon (Falco peregrinus), long-eared owl (Asio otus), common scops owl (Otus scops), Eurasian spoonbill (Platalea leucorodia), white stork (Ciconia ciconia), grey heron (Ardea cinerea), common moorhen (Gallinula chloropus); in the International Union for Conservation of Nature (IUCN) “vulnerable” Spanish imperial eagle (Aquila adalberti), lesser kestrel (Falco naumanni) and great bustard (Otis tarda); and in the IUCN “near threatened” red kite (Milvus milvus). The highest seropositivity by species was observed in the Eurasian eagle owl (Bubo bubo) (68.1%, 98 of 144). The main risk factors associated with T. gondii seropositivity in wild birds were age and diet, with the highest exposure in older animals and in carnivorous wild birds. The results showed that T. gondii infection is widespread and can be at a high level in many wild birds in Spain, most likely related to their feeding behaviour

    Exact analysis of summary statistics for continuous-time discrete-state Markov processes on networks using graph-automorphism lumping

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    We propose a unified framework to represent a wide range of continuous-time discrete-state Markov processes on networks, and show how many network dynamics models in the literature can be represented in this unified framework. We show how a particular sub-set of these models, referred to here as single-vertex-transition (SVT) processes, lead to the analysis of quasi-birth-and-death (QBD) processes in the theory of continuous-time Markov chains. We illustrate how to analyse a number of summary statistics for these processes, such as absorption probabilities and first-passage times. We extend the graph-automorphism lumping approach [Kiss, Miller, Simon, Mathematics of Epidemics on Networks, 2017; Simon, Taylor, Kiss, J. Math. Bio. 62(4), 2011], by providing a matrix-oriented representation of this technique, and show how it can be applied to a very wide range of dynamical processes on networks. This approach can be used not only to solve the master equation of the system, but also to analyse the summary statistics of interest. We also show the interplay between the graph-automorphism lumping approach and the QBD structures when dealing with SVT processes. Finally, we illustrate our theoretical results with examples from the areas of opinion dynamics and mathematical epidemiology
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