415 research outputs found

    Magnitud, composición y patrones espaciotemporales de la mortalidad de vertebrados en las carreteras a escala regional

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    Although roadkill studies on a large scale are challenging, they can provide valuable information to assess the impact of road traffic on animal populations. Over 22 months (between July 2009–June 2010, and April 2011–March 2012) we surveyed 45 road sections of 10 km within a global biodiversity hotspot in Andalusia (87,000 km2), in southern Spain. We divided the region into five ecoregions differing in environmental conditions and landscape characteristics and recorded the relative magnitude, composition and spatiotemporal patterns of vertebrate (birds, mammal, amphibians, and reptiles) mortality. We used roadkill data from monthly surveys of road stretches with different speed limits, traffic volume, road design, and adjacent landscape composition. Roadkills varied over time and were not randomly distributed across ecoregions and road types. Overall, the groups most frequently encountered were mammals (54.4% of total roadkills) and birds (36.2%). Mortality rates in these two groups were higher on highways than on national or local roads, whereas those of amphibians (4.6%) and reptiles (4.3%) did not differ between road types. Except for mammals, the observed variation in vertebrate roadkills across ecoregions reflects the patterns of species richness previously described in the literature. Roadkills were concentrated over relatively short periods and this pattern was repeated over study periods and for all vertebrate classes. Our findings provide baseline information about road types, time periods and taxa with a higher probability of roadkills across an extensive region. These data represent an essential step towards the future implementation of broad–scale mitigation measures.A pesar de que los estudios a gran escala sobre mortalidad de animales en las carreteras son complejos, pueden aportar información valiosa para evaluar la incidencia del tráfico en las poblaciones de animales. Durante 22 meses (entre julio de 2009 y junio de 2010 y entre abril de 2011 y marzo de 2012), muestreamos 45 tramos de carretera de 10 km de longitud distribuidos en una zona con una gran diversidad en la región de Andalucía (87.000 km2), en el sur de España. La región se dividió en cinco ecorregiones con diferentes condiciones ambientales y características del paisaje, y se analizaron la magnitud, la composición y los patrones espaciotemporales de la mortalidad de vertebrados (aves, mamíferos, anfibios y reptiles). Usamos datos de atropellos obtenidos durante muestreos mensuales en tramos de carretera con diferentes límite de velocidad, volumen de tráfico, diseño de la carretera y composición del paisaje adyacente. Los animales atropellados fueron distintos en el tiempo y no se distribuyeron aleatoriamente entre ecorregiones ni entre tipos de carretera. En total, los grupos que se encontraron con mayor frecuencia fueron los mamíferos (el 54,4% de los atropellos registrados) y las aves (el 36,2%). La tasa de mortalidad observada en estos dos grupos fue mayor en autopistas que en carreteras nacionales o locales, mientras que la mortalidad de anfibios (el 4,6%) y de reptiles (el 4,3%) no presentó diferencias entre tipos de carretera. A excepción de los mamíferos, la variación observada de la mortalidad en las carreteras entre las diferentes ecorregiones refleja los patrones de riqueza de especies descritos en las publicaciones científicas. Los atropellos se concentraron en períodos de tiempo relativamente cortos y este patrón se repitió en las dos temporadas de estudio y con respecto a todas las clases de vertebrados. Nuestros resultados proporcionan información de referencia sobre los tipos de carretera, los períodos de tiempo y los taxones con una mayor probabilidad de morir por atropello en una extensa región, lo que supone un paso esencial para la implementación de medidas de mitigación a gran escala.Fil: Canal Piña, David. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Ciencias de la Tierra y Ambientales de La Pampa. Universidad Nacional de La Pampa. Facultad de Ciencias Exactas y Naturales. Instituto de Ciencias de la Tierra y Ambientales de La Pampa; Argentina. Consejo Superior de Investigaciones Científicas; EspañaFil: Camacho, Carlos. Consejo Superior de Investigaciones Científicas; EspañaFil: Martín, Beatriz. Complejo Huerta Grande; EspañaFil: de Lucas, Manuela. Consejo Superior de Investigaciones Científicas; EspañaFil: Ferrer, Miguel. Consejo Superior de Investigaciones Científicas; Españ

    Testing the matching habitat choice hypothesis in nature: phenotype-environment correlation and fitness in a songbird population

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    The matching habitat choice hypothesis holds that individuals with different phenotypes actively select the habitats to which they are best adapted, hence maximizing fitness. Despite the potential implications of matching habitat choice for many ecological and evolutionary processes, very few studies have tested its predictions. Here, we use a 26-year dataset on a spatially structured population of pied flycatchers (Ficedula hypoleuca) to test whether phenotype-dependent dispersal and habitat selection translate into increased fitness, as measured by recruitment success. In our study system, males at the extremes of the body size range segregate into deciduous and coniferous forests through nonrandom dispersal. According to the matching habitat choice hypothesis, fitness of large-sized males is expected to be higher in the deciduous habitat, where they preferentially settle to breed, while the reverse would be true for small-sized males, which are more frequent in the coniferous forest. Our results showed that recruitment success in the coniferous forest increased non-linearly with body size, with males at the middle of the size range having higher fitness than both large and small-sized males. However, no clear trend was observed in the deciduous forest where males of either size had similar fitness. After empirically discarding other important processes potentially confounding matching habitat choice, as genotype- and body condition-dependent dispersal, competitive exclusion remains the most likely force shaping the nonrandom distribution of male pied flycatchers. A conclusive demonstration of the operation and occurrence of matching habitat choice in nature remains therefore to be done.Peer reviewe

    Dynamic behaviour in a nonlinear directional coupler with feedback

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    Design of a RGB-Arduino device for monitoring copper recovery from PCBs

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    The mobile phone industry, one of the fastest advancing sectors in production over the last few decades, has been associated with a high e-waste generation rate. Simultaneously, a high demand for the production of new electronic equipment has led to the scarcity of certain metals. In this context, many recent studies have focused on recovering certain metals from e-waste through the use of bioprocesses. Such recovery processes are based on the action of microorganisms that produce Fe(III) as an oxidant, in order to leach the copper contained in printed circuit boards. During the oxidation-reduction reaction between Fe(III) and metallic Cu, the color of the solution evolves from an initial reddish color, due to Fe(III), to a bluish-green color, due to the oxidized Cu. In this work, a hardware-software prototype is developed, through which the concentrations of the key analytes—Fe(III) and Cu(II)—can be determined in real time by monitoring the color of the solution. This is achieved through the use of a non-invasive system, taking into account the aggressiveness of the solutions used for the bioprocessing of electronic components. In the work presented herein, the evolution of the solution color during the bioprocessing of two different types of waste (i.e., electric cable and mobile phones) is analyzed and then compared with the results obtained for pure metallic copper. The results are validated through comparison of the predicted results with the outcomes of conventional procedures, including offline sampling and analysis of Cu(II) and Fe(III) through atomic absorption and UV-VIS spectroscopy, respectively. The developed monitoring system allows an algorithm to be designed that can fit the evolution of analyte concentrations without the need for sampling or the use of complex, tedious, and expensive analytic techniques. It is also worth noting that the monitoring system is not in direct contact with the solution (which is highly aggressive for the processing of electronic equipment), making the system more durable than classic sensors that must be submerged in the solution. The real-time nature of the obtained information allows for the development of control actions and for corrective measures to be taken without affecting the biomass involved in the process.This work was supported by the Spanish Agencia Estatal de Investigación Project Ref PID2020-117520RA-I00/AEI/10.13039/501100011033.Peer ReviewedObjectius de Desenvolupament Sostenible::12 - Producció i Consum ResponsablesPostprint (published version

    Procesamiento de Eventos Complejos para la determinación de rutas en ciudades inteligentes

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    Una de las principales características de una ciudad inteligente es la publicación de datos abiertos que monitorizan diferentes aspectos de la misma, desde sistemas de movilidad a niveles de polen. Sin embargo, esta información se ofrece a los ciudadanos de forma genérica y carente de contexto. Sin el concurso de las personas en la generación y recogida de información, no es posible tener en cuenta sus preferencias y necesidades, ni el uso que hacen de los servicios. Para reducir este fenómeno y contextualizar los datos abiertos con información acerca de los ciudadanos, diseñamos anteriormente la arquitectura de referencia People as a Service, que permite recopilar información de los usuarios a partir de sus smartphones. En este trabajo vamos un paso más allá en la integración de un motor de inferencia para esta arquitectura usando la tecnología de Procesamiento de Eventos Complejos. En particular, recopilamos información de los sensores del smartphone para analizarla, transformándola en conocimiento sobre los hábitos del usuario. La posterior combinación de este conocimiento con los datos abiertos de la ciudad, permitirá que sus servicios puedan adaptarse a cada persona.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    No surviving evolved companions to the progenitor of supernova SN 1006

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    Type Ia supernovae are thought to occur as a white dwarf made of carbon and oxygen accretes sufficient mass to trigger a thermonuclear explosion1^{1}. The accretion could occur slowly from an unevolved (main-sequence) or evolved (subgiant or giant) star2,3^{2,3}, that being dubbed the single-degenerate channel, or rapidly as it breaks up a smaller orbiting white dwarf (the double- degenerate channel)3,4^{3,4}. Obviously, a companion will survive the explosion only in the single-degenerate channel5^{5}. Both channels might contribute to the production of type Ia supernovae6,7^{6,7} but their relative proportions still remain a fundamental puzzle in astronomy. Previous searches for remnant companions have revealed one possible case for SN 15728,9^{8,9}, though that has been criticized10^{10}. More recently, observations have restricted surviving companions to be small, main-sequence stars11,12,13^{11,12,13}, ruling out giant companions, though still allowing the single-degenerate channel. Here we report the result of a search for surviving companions to the progenitor of SN 100614^{14}. None of the stars within 4' of the apparent site of the explosion is associated with the supernova remnant, so we can firmly exclude all giant and subgiant companions to the progenitor. Combined with the previous results, less than 20 per cent of type Iae occur through the single degenerate channel.Comment: Published as a letter in Nature (2012 September 27

    Multiple characterization study on porosity and pore structure of calcium phosphate cements

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    Characterization of the intricate pore structure of calcium phosphate cements is a key step to successfully link the structural properties of these synthetic bone grafts with their most relevant properties, such as in vitro or in vivo behaviour, drug loading and release properties, or degradation over time. This is a challenging task due to the wide range of pore sizes in calcium phosphate cements, compared to most other ceramic biomaterials. This work provides a critical assessment of three different techniques based on different physical phenomena, namely mercury intrusion porosimetry (MIP), Nitrogen sorption, and thermoporometry (TPM) for the detailed characterization of four calcium phosphate cements with different textural properties in terms of total porosity, pore size distribution (PSD), and pore entrance size distribution (PESD). MIP covers a much wider size range than TPM and Nitrogen sorption, offering more comprehensive information at the micrometer level. TPM, and especially Nitrogen sorption, are non-destructive techniques and, although they cover a limited size range, provide complementary information regarding pore structure associated with crystal shape at the nanoscale, recording both PSD and PESD in a single experiment. MIP tended to register smaller sizes, especially at low L/P ratios, due to the network effect, which has a strong influence on the outcome of this technique. Statement of significance The detailed characterisation of the porosity of calcium phosphate cements is of paramount importance, since it is a key parameter influencing some of the most relevant features, like mechanical properties, degradation rate or drug loading and release kinetics. However, this is a challenging task because, once hardened, calcium phosphate cements present an intricate morphology, consisting of a network of precipitated crystals, which generate a high intrinsic micro/nano porosity, with pore sizes covering six orders of magnitude. This work provides for the first time a critical assessment of the advantages and limitations of three different techniques, namely mercury intrusion porosimetry, Nitrogen sorption and Thermoporometry, for the characterisation of the porosity of four calcium phosphate cements with different textural propertiePeer ReviewedPostprint (author's final draft

    Nest-dwelling ectoparasites reduce begging effort in Pied Flycatcher Ficedula hypoleuca nestlings

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    Parasitized nestlings might be expected to increase begging effort to obtain additional resources to compensate for those sequestered by their parasites. However, begging is costly and chicks harbouring parasites may find it more difficult to attain high begging levels. Consequently, we predicted that, for the same level of nutritional need, nestlings that are parasitized will invest less in begging than those that are not parasitized. We tested this prediction by measuring begging in Pied Flycatcher Ficedula hypoleuca nestlings parasitized with haematophagous mites Dermanyssus gallinoides and Dermanyssus gallinae and blowfly larvae Protocalliphora azurea, and subjected to different levels of food deprivation in order to control for short-term nutritional need. Nestlings from nests with ectoparasites spent less time begging than those from nests without parasites, especially when very hungry, although there was no association with latency to beg or begging intensity. Our results suggest that time invested in begging may indicate not only the level of need, but also nestling parasitism status.Peer Reviewe

    One step towards dynamically programmable things: an implementation using Beacons

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    The number of devices connected to the internet is constantly increasing. This large amount of devices can be used to improve people’s interaction with their environment. However, this also implies an increase in the complexity when interacting with so many heterogeneous devices. Automating this process is key to keep up with this growth. This is the purpose of the People as a Service model (PeaaS), which works towards developing virtual profiles for every user in their own mobile devices under their full control. These profiles allow to establish preferences and predefined parameters, which are then used by the devices they connect to. By integrating both the information in the users’ virtual profiles and the information given by the devices they connect to, we can create a context in which to make smart decisions and apply them to the devices, all of this in a decentralised way. This allows for a programmatically configuration of the devices without the need of the user’s intervention. In order to put the proposal in action, we have developed a treasure hunting game as a proof of concept to bring to the spotlight the utility of an environment with programmatically adapted devices.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A programming framework for people as a service

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    The number of devices connected to the internet is constantly growing, which implies an increased complexity when interacting with so many heterogeneous devices. Automating this process is key to keep up with this growth. This People as a Service model works towards developing virtual profiles for every user in their own mobile devices and under their full control. These profiles allow to establish user preferences and predefined parameters, which are then applied by the devices they connect to. By integrating both the information in the virtual profiles and these devices, we can create a context in which to make smart decisions and apply them automatically, all of this in a decentralised way. In order to show our proposal in action, we have developed a treasure hunting game as a proof of concept to bring to the spotlight the utility of an environment with programmatically adapted devices.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech
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