283 research outputs found
First report of Tomato torrado virus on weed hosts in Spain
Alfaro Fernández, AO.; Córdoba-Sellés, C.; Cebrián, M.; Herrera-Vásquez, J.; Sanchez Navarro, JA.; Juárez, M.; Espino, A.... (2088). First report of Tomato torrado virus on weed hosts in Spain. Plant Disease. 92(5):831-831. https://doi.org/10.1094/pdis-92-5-0831b83183192
Crowding of Polymer Coils and Demixing in Nanoparticle-Polymer Mixtures
The Asakura-Oosawa-Vrij (AOV) model of colloid-polymer mixtures idealizes
nonadsorbing polymers as effective spheres that are fixed in size and
impenetrable to hard particles. Real polymer coils, however, are intrinsically
polydisperse in size (radius of gyration) and may be penetrated by smaller
particles. Crowding by nanoparticles can affect the size distribution of
polymer coils, thereby modifying effective depletion interactions and
thermodynamic stability. To analyse the influence of crowding on polymer
conformations and demixing phase behaviour, we adapt the AOV model to mixtures
of nanoparticles and ideal, penetrable polymer coils that can vary in size. We
perform Gibbs ensemble Monte Carlo simulations, including trial
nanoparticle-polymer overlaps and variations in radius of gyration. Results are
compared with predictions of free-volume theory. Simulation and theory
consistently predict that ideal polymers are compressed by nanoparticles and
that compressibility and penetrability stabilise nanoparticle-polymer mixtures.Comment: 18 pages, 4 figure
NUEVAS APORTACIONES AL CATÁLOGO FAUNÍSTICO DE LOS QUIRONOMIDOS (DIPTERA: CHIRONOMIDAE) DEL PARQUE NACIONAL DE DOÑANA (SW DE ESPAÑA)
Twenty one species of chironomids have been recorded from Doñana National Park. Amongst these, 12 records are new for the area and 4 for the Iberian península. Total number of chironomid species known in the area rises to 35. A complete list of species including comments on their ecology and biogeography is includedEn los muestreos realizados para la ejecución del presente trabajo se han capturado ejemplares de 21 especies, de ellas 12 son nuevas citas para el Parque Nacional de Doñana y 4 para la Península Ibérica. Con la mencionada aportación, el número de especies de Quironómidos citados para el Parque asciende a 35. Se presenta una relación de las 21 especies capturadas con consideraciones de tipo ecológico y comentarios sobre las implicaciones biogeográficas de las especies más interesantes
The Lamé Class of Lorenz Curves.
In this paper, the class of Lamé Lorenz curves is studied. This family has the advantage of modeling inequality with a single parameter. The family has a double motivation: it can be obtain from an economic model and from simple transformations of classical Lorenz curves. The underlying cumulative distribution functions have a simple closed form, and correspond to the Singh-Maddala and Dagum distributions, which are well known in the economic literature. The Lorenz order is studied and several inequality and polarization measures are obtained, including Gini, Donaldson-Weymark-Kakwani, Pietra and Wolfson indices. Some extensions of the Lamé family are obtained. Fitting and estimation methods under two different data configuration are proposed. Empirical applications with real data are given. Finally, some relationships with other curves are included.The authors thank to Ministerio de Econom a y Competitividad, project
ECO2010-15455, for partial support. The second author thanks to the Ministerio
de Educaci on (FPU AP-2010-4907) for partial support. We are grateful
for the constructive suggestions provided by the reviewers, which improved
the paper
Estudio de la valoración del dolor articular y del grado de satisfacción,tras infiltración con plasma rico en fibrina en pacientes con artrosis de rodilla.
The definition of platelet rich plasma (PRP) is still controversial, though it can be described in general terms as ?a volumeof autologous plasma that contains a higher platelet concentration than the physiological basal concentration?. A retrospective observational analytical study was carried out in our hospital in order to assess the results and satisfaction of patients that had undergone PRF injection in knee. Between January and December of 2017, 80 gonoarthrosis patients treated with PRF injection were selected by the Orthopaedic Surgery and Rehabilitation Department, all of whom attended several medical appointments to check their recovery. Those cases that did not follow an appropriate clinical follow-up were dismissed from the study.Pain before treatment was assessed by the Numeric Rating Scale, with a mean of 8.48. A statistically significant decrease was observed after treatment (p<0.001), with a 4.87 mean and a 5.00 post-injection median. Regarding walking perimeter, most patients walked a median of 30 minutes and 55.3 minute mean, and their walking autonomy increased after treatment, doubling the median to 60 minutes, with an average of 93.15 minutes of pain-free walking. This 37.8 minute increase in the walking ability impliesa statistically significant improvement (p<0.001). A significant decrease in analgesics intake after treatment was also observed, being 81.3% patients who needed analgesia prior to treatment (n=61), and just 49.3% (n=37) after the procedure.Consequently,there is a significative improvement of pain, walking perimeter and absolute intake of analgesics that cannot be explained by any variable prior to PRF injection
Climate-driven impacts of exotic species on marine ecosystems
Aim
Temperature is fundamental to the physiological and ecological performance of marine organisms, but its role in modulating the magnitude of ecological impacts by exotic species remains unresolved. Here, we examine the relationship between thermal regimes in the range of origin of marine exotic species and sites of measured impact, after human-induced introduction. We compare this relationship with the magnitude of impact exerted by exotic species on native ecosystems.
Location
Global.
Time period
1977–2017 (meta-analysis).
Major taxa studied
Marine exotic species.
Methods
Quantitative impacts of exotic species in marine ecosystems were obtained from a global database. The native range of origin of exotic species was used to estimate the realized thermal niche for each species and compared with the latitude and climatic conditions in recipient sites of recorded impact of exotic species. The difference in median temperatures between recipient sites and the thermal range of origin (i.e., thermal midpoint anomaly) was compared with the magnitude of effect sizes by exotic species on native species, communities and ecosystems.
Results
Recorded impacts occurred predominantly within the thermal niche of origin of exotic species, albeit with a tendency toward higher latitudes and slightly cooler conditions. The severity of impacts by exotic species on abundance of native taxa displayed a hump-shaped relationship with temperature. Peak impacts were recorded in recipient sites that were 2.2°C cooler than the thermal midpoint of the range of origin of exotic species, and impacts decreased in magnitude toward higher and lower thermal anomalies.
Main conclusions
Our findings highlight how temperature and climatic context influence ecological impacts by exotic species in marine ecosystems and the implications for existing and novel species interactions under climate change.En prensa5,14
Progress in Detection and Projection of Climate Change in Spain since the 2010 CLIVAR-Spain regional climate change assessment report
The Iberian Peninsula region offers a challenging benchmark for climate variability studies for several reasons. It exhibits a wide variety of climatic regimes, ranging from wet Atlantic climates with annual precipitation around 2000 mm, to extensive semiarid regions with severe hydrological stress, to even cold alpine environments in some isolated areas
A first-principles approach to electrical transport in atomic-scale nanostructures
We present a first-principles numerical implementation of Landauer formalism
for electrical transport in nanostructures characterized down to the atomic
level. The novelty and interest of our method lies essentially on two facts.
First of all, it makes use of the versatile Gaussian98 code, which is widely
used within the quantum chemistry community. Secondly, it incorporates the
semi-infinite electrodes in a very generic and efficient way by means of Bethe
lattices. We name this method the Gaussian Embedded Cluster Method (GECM). In
order to make contact with other proposed implementations, we illustrate our
technique by calculating the conductance in some well-studied systems such as
metallic (Al and Au) nanocontacts and C-atom chains connected to metallic (Al
and Au) electrodes. In the case of Al nanocontacts the conductance turns out to
be quite dependent on the detailed atomic arrangement. On the contrary, the
conductance in Au nanocontacts presents quite universal features. In the case
of C chains, where the self-consistency guarantees the local charge transfer
and the correct alignment of the molecular and electrode levels, we find that
the conductance oscillates with the number of atoms in the chain regardless of
the type of electrode. However, for short chains and Al electrodes the even-odd
periodicity is reversed at equilibrium bond distances.Comment: 14 pages, two-column format, submitted to PR
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