287 research outputs found
Climate change promotes hybridisation between deeply divergent species
Rare hybridisations between deeply divergent animal species have been reported for decades in a wide range of taxa, but have often remained unexplained, mainly considered chance events and reported as anecdotal. Here, we combine field observations with long-term data concerning natural hybridisations, climate, land-use, and field-validated species distribution models for two deeply divergent and naturally sympatric toad species in Europe (Bufo bufo and Bufotes viridis species groups). We show that climate warming and seasonal extreme temperatures are conspiring to set the scene for these maladaptive hybridisations, by differentially affecting life-history traits of both species. Our results identify and provide evidence of an ultimate cause for such events, and reveal that the potential influence of climate change on interspecific hybridisations goes far beyond closely related species. Furthermore, climate projections suggest that the chances for these events will steadily increase in the near future
MIMYCS: A framework for simulating maize kernels mycotoxin contamination in Europe.
Mycotoxins are toxic compounds, produced by fungi and recognized as the main cause of chronic intoxications in the world. Maize is one of the crops subjected to the most critical mycotoxin problems throughout the world. Mycotoxin contamination in maize grain is the result of a complex plant pathosystem composed of maize plants, toxigenic fungi and insect borers. Warming of the climate system could have an important impact on the system, leading to mycotoxin contamination in grain maize and the potential effects are very difficult to foresee. The project MIMYCS has aimed at the development of a simulation model system to simulate at EU scale mycotoxin contamination in maize grain in different climatic, environmental and agro-management situations. The MIMYCS model system has been developed as composed by three main model components: i) MIMYCS.Maize, which integrates the crop model CropSyst and simulates maize phenological development and moisture in kernels during their development and maturation, ii) MIMYCS.Borers simulating two maize borers (Ostrinia nubilalis and Sesamia nonagrioides) phenological development and their damage to the ear, enhancing fungi growth and development, iii) MIMYCS.Fungi simulating fungi development and their interactions, using information received from Maize and the Borers modules. Finally, the MIMYCS simulation system, can quantify the risk of mycotoxin (aflatoxins, fumonisins, deoxynivalenol) contamination in maize grain. As a first application, MIMYCS has been used to predict and evaluate the effect of climate change on maize grain mycotoxin contamination in Europe. Future applications of MIMYCS will include its use as a decision support system to manage mycotoxin contamination during the field phase.
During the development of the project training activity have included: i) process-based modelling and biophysical model framework development, ii) basic concepts of insect pest population dynamics modelling iii) object-oriented and component-oriented programming with C#, iv) writing of scientific papers, v) project management, vi) agrometeorological analysis and crop forecast, vii) writing of project proposalsJRC.H.4-Monitoring Agricultural Resource
PROJECT MIMYCS: A SIMULATION MODEL SYSTEM FOR SIMULATING MYCOTOXIN CONTAMINATION IN MAIZE GRAIN IN EUROPE
Abstract Mycotoxins are toxic compounds produced by fungi infecting crops starting from the field phase. Maize is one of the crops subjected to the most critical mycotoxin problems. The FP7 Marie Curie Project MIMYCS aims at the development of a simulation model system to simulate mycotoxin contamination in grain maize. MIMYCS is being implemented using the component-oriented paradigm both for model and utility components. It will be composed of three sub-models simulating maize, insect borers and fungi development. First results of the project include i) the development of a generic insect phenological model parameterized for the maize borers Ostrinia nubilalis and Sesamia nonagrioides, and applications under climate change scenarios; ii) the development of a biophysical model for the simulation of maize grain moisture during development and maturation. The sub-model simulating fungi development is under development
Study on the generalized formulations with the aim to reproduce the viscoelastic dynamic behavior of polymers
Appropriate modelling of the real behavior of viscoelastic materials is of fundamental importance for correct studies and analyses of structures and components where such materials are employed. In this paper, the potential to employ a generalized Maxwell model and the relative fraction derivative model is studied with the aim to reproduce the experimental behavior of viscoelastic materials. For both models, the advantage of using the pole-zero formulation is demonstrated and a specifically constrained identification procedure to obtain the optimum parameters set is illustrated. Particular emphasis is given on the ability of the models to adequately fit the experimental data with a minimum number of parameters, addressing the possible computational issues. The question arises about the minimum number of experimental data necessary to estimate the material behavior in a wide frequency range, demonstrating that accurate results can be obtained by knowing only the data of the upper and low frequency plateaus plus the ones at the loss tangent peak
Drilling down hotspots of infraspecific diversity to bring them into on-ground conservation of threatened species
Unprecedented rates of biodiversity loss raise the urgency for preserving species ability to cope with ongoing global changes. An approach in this direction is to target intra-specific hotspots of genetic diversity as conservation priorities. However, these hotspots are often identified by sampling at a spatial resolution too coarse to be useful in practical management of threatened species, hindering the long-appealed dialog between conservation stakeholders and conservation genetic researchers. Here, we investigated the spatial and temporal variation in species presence, genetic diversity, as well as potential risk factors, within a previously identified hotspot of genetic diversity for the endangered Apennine yellow-bellied toad Bombina pachypus. Our results show that this hotspot is neither a geographically homogeneous nor a temporally stable unit. Over a time-window spanning 10–40 years since previous assessments, B. pachypus populations declined in large portions of their hotspot, and their genetic diversity levels decreased. Considering the demographic trend, genetic and epidemiological data, and models of current and future climatic suitability, populations at the extreme south of the hotspot area still qualify for urgent in-situ conservation actions, whereas northern populations would be better managed through a mix of in-situ and ex-situ actions. Our results emphasize that identifying hotspots of genetic diversity, albeit an essential step, does not suffice to warrant on-ground conservation of threatened species. Hotspots should be analyzed at finer geographic and temporal scales, to provide conservation stakeholders with key knowledge to best define conservation priorities, and to optimize resource allocation to alternative management practices
PReferentially Expressed Antigen in MElanoma (PRAME):preliminary communication on a translational tool able to early detect Oral Malignant Melanoma (OMM)
: Oral malignant melanoma (OMM) has a prevalence less than 1% of all melanomas and it commonly develops on the oral mucosa following a slow and unspecific transformation of unstable melanocytic lesions, often resulting in a diagnostic delay. The marker PReferentially Expressed Antigen in MElanoma (PRAME) seems to be a valid tool to investigate the biological and histological nature of cutaneous melanocytic lesions, but to date its use to characterize pigmented lesions in the oral cavity is largely unexplored. The aim of this study was to create preliminary knowledge on the PRAME expression in OMM, and to compare its expression respect to other dysplastic pigmented lesions of the oral cavity. Interestingly, PRAME has been demonstrated to be reliable in the clinical conditions investigated in our pilot study; in fact, it has clearly differentiated the cases of Melanoma, which showed diffuse and intense positivity (score 6+/7+) to PRAME, from the other melanocytic nevi, which resulted to be mainly negative to PRAME. This means a better differential diagnosis, a reliable early diagnosis and a proper clinical/surgical management of the oncological lesions. In conclusion, PRAME can be a valid qualitative marker for differential diagnosis, not only in cutaneous melanomas, but also in malignant melanoma of the entire head and neck area
Electronic transport, ionic activation energy and trapping phenomena in a polymer-hybrid halide perovskite composite
Abstract The exploitation of methylammonium lead iodide perovskite-polymer composites is a promising strategy for the preparation of photoactive thin layers for solar cells. The preparation of these composites is a simple fabrication method with improved moisture stability when compared to that of pristine perovskite films. To deepen the understanding of the charge transport properties of these films, we investigated charge carrier mobility, traps, and ion migration. For this purpose, we applied a combinatory measurement approach that proves how such composites can still retain an ambipolar charge transport nature and the same mobility values of the related perovskite. Furthermore, thermally stimulated current measurements revealed that the polymer influenced the creation of additional defects during film formation without affecting charge mobility. Finally, impedance spectroscopy measurements suggested the addition of starch may hinder ion migration, which would require larger activation energies to move ions in composite films. These results pave the way for new strategies of polymer-assisted perovskite film development
Monodispersed and size-controlled multibranched gold nanoparticles with nanoscale tuning of surface morphology
A novel seed-mediated synthetic route to produce multibranched gold nanoparticles is reported, in which it is possible to precisely tune both their size and nanostructuration, while maintaining an accurate level of monodispersion. The nanoscale control of surface nanoroughness/branching, ranging from small bud-like features to elongated spikes, allows to obtain fine tuning of the nanoparticle optical properties, up to the red and near-IR region of the spectrum. Such anisotropic nanostructures were demonstrated to be excellent candidates for SERS applications, showing significantly higher signals with respect to the standard spherical nanoparticles
Coverage of vertebrate species distributions by Important Bird and Biodiversity Areas and Special Protection Areas in the European Union
Peer reviewe
In Vivo toxicity assessment of gold nanoparticles in Drosophila melanogaster
The growing use of nanomaterials in commercial goods and novel technologies is generating increasing questions about possible risks for human health and environment, due to the lack of an in-depth assessment of their potential toxicity. In this context, we investigated the effects of citrate-capped gold nanoparticles (AuNPs) on the model system Drosophila melanogaster upon ingestion. We observed a significant in vivo toxicity of AuNPs, which elicited clear adverse effects in treated organisms, such as a strong reduction of their life span and fertility, presence of DNA fragmentation, as well as a significant overexpression of the stress proteins. Transmission electron microscopy demonstrated the localization of the nanoparticles in tissues of Drosophila. The experimental evidence of high in vivo toxicity of a nanoscale material, which is widely considered to be safe and biocompatible in its bulk form, opens up important questions in many fields, including nanomedicine, material science, health, drug delivery and risk assessment
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