1,078 research outputs found
A first assessment of genetic variability in the longhorn beetle Rosalia alpina (Coleoptera: Cerambycidae) from the Italian Apennines
The Rosalia longicorn (Rosalia alpina) is a strictly protected saproxylic beetle, widely distributed in Central and Southern Europe and mainly associated with ancient beech forests. To improve knowledge about the conservation status of R. alpina in Italy, available molecular markers (microsatellites and mitochondrial cytochrome c oxidase I(COI)) were tested for the first time on Italian populations. The study was performed in four sampling sites distributed in two areas placed in Northern (“Foreste Casentinesi” National Park) and Central Apennines (“Abruzzo, Lazio and Molise” National Park) where populational data about Rosalia longicorn were collected in the framework of the European LIFE MIPP Project. The genetic relationship among Apennine and Central/South-eastern European populations was explored by a comparison with mitochondrial DNA (mtDNA) data from literature. Microsatellite markers were only partially informative when applied to R. alpina Italian individuals, although providing some preliminary indication on an extensive gene flow among populations from the Apennines and local ongoing processes of genetic erosion. Genetic data are consistent with previous ecological data suggesting that the maintenance of variability in this species could be related to both habitat continuity and preservation of large senescent or standing dead trees in forests. Finally, a peculiar origin of the Apennine populations of R. alpina from a putative “Glacial Refugium” in Italy was inferred through COI data. The high genetic distance scored among the analysed populations and those from Central and South-eastern Europe indicates that the R. alpina deme from Apennine Mountains might represent a relevant conservation unit in Europe. Further genetic analyses will allow assessing other possible conservation units of R. alpina and, thus, defining large-scale conservation strategies to protect this endangered longhorn beetle in Europe
LiSc(BH_4)_4 as a Hydrogen Storage Material: Multinuclear High-Resolution Solid-State NMR and First-Principles Density Functional Theory Studies
A lithium salt of anionic scandium tetraborohydride complex, LiSc(BH_4)_4, was studied both experimentally and theoretically as a potential hydrogen storage medium. Ball milling mixtures of LiBH_4 and ScCl_3 produced LiCl and a unique crystalline hydride, which has been unequivocally identified via multinuclear solid-state nuclear magnetic resonance (NMR) to be LiSc(BH_4)_4. Under the present reaction conditions, there was no evidence for the formation of binary Sc(BH_4)_3. These observations are in agreement with our first-principles calculations of the relative stabilities of these phases. A tetragonal structure in space group I (#82) is predicted to be the lowest energy state for LiSc(BH_4)_4, which does not correspond to structures obtained to date on the crystalline ternary borohydride phases made by ball milling. Perhaps reaction conditions are resulting in formation of other polymorphs, which should be investigated in future studies via neutron scattering on deuterides. Hydrogen desorption while heating these Li−Sc−B−H materials up to 400 °C yielded only amorphous phases (besides the virtually unchanged LiCl) that were determined by NMR to be primarily ScB_2 and [B_(12)H_(12)]^(−2) anion containing (e.g., Li_2B_(12)H_(12)) along with residual LiBH_4. Reaction of a desorbed LiSc(BH_4)_4 + 4LiCl mixture (from 4LiBH_4/ScCl_3 sample) with hydrogen gas at 70 bar resulted only in an increase in the contents of Li_2B_(12)H_(12) and LiBH_4. Full reversibility to reform the LiSc(BH_4)_4 was not found. Overall, the Li−Sc−B−H system is not a favorable candidate for hydrogen storage applications
El desafío de la calidad : un mensaje pedagógico básico para el trabajo experimental en química analítica
El trabajo se orienta hacia el logro del mejoramiento de la enseñanza experimental en el laboratorio de química analítica y se realiza desde el modelo de la investigación-acción. La química analítica es una actitud intelectual y se la considera una disciplina científica; la enseñanza de su teoría y de la programación del análisis mediante la aplicación del proceso analítico tiene, como objetivo pedagógico básico, generar una actitud intelectual. Se presenta un enfoque conceptual del proceso analítico total para la enseñanza experimental, orientada para que el estudiante aprenda a obtener información analítica de calidad. Se reúnen y evalúan diferentes prácticos en el laboratorio, de complejidad creciente, analizándose los resultados de las experiencias. El desafío pedagógico invita a revisar con profundidad la concepción sobre la educación permanente en química analítica y, en particular, del trabajo experimental, dado que las nuevas tecnologías sufren rápidos cambios y generalmente no son utilizadas en su máximo rendimiento.The aim of this work is to improve the experimental teaching in Analytical Chemistry Labs. It is being developed from the investigation-action model. Analytical Chemistry is an intelectual attitude. We think about it as a scientific subject. The basic pedagogic aim of teaching theory and programming the analysis applying the analytical process is to incorporate it into mental structures. A conceptual approach to complete analytical process in experimental teaching is shown. The student is guided to obtain qualified analytical information. Different practical works of increasing complexity are gathered and evaluated. The results of these experiencies are analysed. The pedagogic challenge is to revise thoroughly the understanding of everyday teaching in Analytical Chemistry. Specially experimental work, since new technologies undergo quick changes and they are not always efficiently applied
Guidelines for the monitoring of Rosalia alpina
Copyright Alessandro Campanaro et al. Rosalia alpina (Linnaeus, 1758) is a large longhorn beetle (Coleoptera: Cerambycidae) which is protected by the Habitats Directive and which typically inhabits beech forests characterised by the presence of mature, dead (or moribund) and sun-exposed trees. A revision of the current knowledge on systematics, ecology and conservation of R. alpina is reported. The research was carried out as part of the LIFE MIPP project which aims to find a standard monitoring method for saproxylic beetles protected in Europe. For monitoring this species, different methods were tested and compared in two areas of the Apennines, utilising wild trees, logs and tripods (artificially built with beech woods), all potentially suitable for the reproduction of the species. Even if all methods succeeded in the survey of the target species, these results showed that the use of wild trees outperformed other methods. Indeed, the use of wild trees allowed more adults to be observed and required less intensive labour. However, monitoring the rosalia longicorn on wild trees has the main disadvantage that they can hardly be considered “standard sampling units”, as each tree may be differently attractive to adults. Our results demonstrated that the most important factors influencing the attraction of single trunks were wood volume, sun-exposure and decay stage. Based on the results obtained during the project LIFE MIPP, as well as on a literature review, a standard monitoring method for R. alpina was developed
Ісак Мазепа: перші кроки у великій політиці
Досліджується становлення світоглядних позицій та формування політичних поглядів І. Мазепи.Исследуется становление мировоззренческих позиций и формирование политических взглядов И. Мазепы.Formation world outlook positions and formation of political views of I. Mazepa is investigated
Investigation of EMIC wave scattering as the cause for the BARREL 17 January 2013 relativistic electron precipitation event: A quantitative comparison of simulation with observations
Abstract Electromagnetic ion cyclotron (EMIC) waves were observed at multiple observatory locations for several hours on 17 January 2013. During the wave activity period, a duskside relativistic electron precipitation (REP) event was observed by one of the Balloon Array for Radiation belt Relativistic Electron Losses (BARREL) balloons and was magnetically mapped close to Geostationary Operational Environmental Satellite (GOES) 13. We simulate the relativistic electron pitch angle diffusion caused by gyroresonant interactions with EMIC waves using wave and particle data measured by multiple instruments on board GOES 13 and the Van Allen Probes. We show that the count rate, the energy distribution, and the time variation of the simulated precipitation all agree very well with the balloon observations, suggesting that EMIC wave scattering was likely the cause for the precipitation event. The event reported here is the first balloon REP event with closely conjugate EMIC wave observations, and our study employs the most detailed quantitative analysis on the link of EMIC waves with observed REP to date. Key PointsQuantitative analysis of the first balloon REP with closely conjugate EMIC wavesOur simulation suggests EMIC waves to be a viable cause for the REP eventThe adopted model is proved to be applicable to simulating the REP event
Direct imaging of structural disordering and heterogeneous dynamics of fullerene molecular liquid
Structural rearrangements govern the various properties of disordered systems and visualization of these dynamical processes can provide critical information on structural deformation and phase transformation of the systems. However, direct imaging of individual atoms or molecules in a disordered state is quite challenging. Here, we prepare a model molecular system of C70 molecules on graphene and directly visualize the structural and dynamical evolution using aberration-corrected transmission electron microscopy. E-beam irradiation stimulates dynamics of fullerene molecules, which results in the first-order like structural transformation from the molecular crystal to molecular liquid. The real-time tracking of individual molecules using an automatic molecular identification process elucidates the relaxation behavior of a stretched exponential functional form. Moreover, the directly observed heterogeneous dynamics bear similarity to the dynamical heterogeneity in supercooled liquids near the glass transition. Fullerenes on graphene can serve as a new model system, which allows investigation of molecular dynamics in disordered phases
Gene conversion in human rearranged immunoglobulin genes
Over the past 20 years, many DNA sequences have been published suggesting that all or part of the V<sub>H</sub> segment of a rearranged immunoglobulin gene may be replaced in vivo. Two different mechanisms appear to be operating. One of these is very similar to primary V(D)J recombination, involving the RAG proteins acting upon recombination signal sequences, and this has recently been proven to occur. Other sequences, many of which show partial V<sub>H</sub> replacements with no addition of untemplated nucleotides at the V<sub>H</sub>–V<sub>H</sub> joint, have been proposed to occur by an unusual RAG-mediated recombination with the formation of hybrid (coding-to-signal) joints. These appear to occur in cells already undergoing somatic hypermutation in which, some authors are convinced, RAG genes are silenced. We recently proposed that the latter type of V<sub>H</sub> replacement might occur by homologous recombination initiated by the activity of AID (activation-induced cytidine deaminase), which is essential for somatic hypermutation and gene conversion. The latter has been observed in other species, but not in human Ig genes, so far. In this paper, we present a new analysis of sequences published as examples of the second type of rearrangement. This not only shows that AID recognition motifs occur in recombination regions but also that some sequences show replacement of central sections by a sequence from another gene, similar to gene conversion in the immunoglobulin genes of other species. These observations support the proposal that this type of rearrangement is likely to be AID-mediated rather than RAG-mediated and is consistent with gene conversion
Understanding decentralization: deconcentration and devolution processes in the French and Italian cultural sectors
none3noPurpose – Decentralization is a widespread and international phenomenon in public administration. Despite the interest of public management scholars, an in-depth analysis of the interrelationship between two of its forms – deconcentration and devolution – and its impact on policy and management capacities at the local level is seldom investigated. Design/methodology/approach – This article addresses this gap by examining the implementation of deconcentration and devolution processes in France and Italy in the cultural field, combining the analysis of national reform processes with in-depth analyses of two regional cases. The research is the result of document analysis, participatory observation and semi-structured interviews. Findings – The article reconstructs the impacts of devolution and deconcentration processes on the emergence of policy and management capacity in two regions (Rhone-Alpes and Piedmont) in the cultural sector. The article shows that decentralization in the cultural sector in France and Italy is the result of different combinations of devolution and deconcentration processes, that the two processes mutually affect their effectiveness, and that this effectiveness is deeply linked to the previous policy and management capacity of the central state in a specific field/country. Originality/value – The article investigates decentralization as a result of the combination of deconcentration and devolution in comparative terms and in a specific sector of implementation, highlighting the usefulness of this approach also for other sectors/countries.mixedSantagati, Maria Elena; Bonini Baraldi, Sara; Zan, LucaSantagati, Maria Elena; Bonini Baraldi, Sara; Zan, Luc
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