456 research outputs found
140 ans d'aménagement forestier en Espagne.
Cite les principaux faits historiques qui sont à l'origine de la mise en place et des premiers pas de l'aménagement forestier en Espagne pendant la deuxième moitié du XIXè siècle, ainsi que l'évolution au cours du XXè siècle et son état actuel. Si le bilan de ces 140 ans de pratique d'aménagement est globalement très positif, il reste cependant à combler d'importantes lacunes notamment en ce qui concerne les forêts issues de reboisements, ainsi qu'en ce qui concerne les méthodes de conversion fortement conditionnées par des facteurs sociaux et saisonniers surtout dans les forêts feuillues méditerranéennes souvent dégradées
Field induced magnetic transition and metastability in Co substituted
A detailed investigation of first order ferrimagnetic (FRI) to
antiferromagnetic (AFM) transition in Co (15%) doped is carried out.
These measurements demonstrate anomalous thermomagnetic irreversibility and
glass-like frozen FRI phase at low temperatures. The irreversibility arising
between the supercooling and superheating spinodals is distinguised in an
ingenious way from the irreversibility arising due to kinetic arrest. Field
annealing measurements shows reentrant FRI-AFM-FRI transition with increasing
temperature. These measurements also show that kinetic arrest band and
supercooling band are anitcorrelated i.e regions which are kinetically arrested
at higher temperature have lower supercooling temperature and vice versa.Comment: 10 pages, 8 figure
Electronic excitation spectra of cerium oxides: from ab initio dielectric response functions to Monte Carlo electron transport simulations
Nanomaterials made of the cerium oxides CeO and CeO have a broad
range of applications, from catalysts in automotive, industrial or energy
operations to promising materials to enhance hadrontherapy effectiveness in
oncological treatments. To elucidate the physico-chemical mechanisms involved
in these processes, it is of paramount importance to know the electronic
excitation spectra of these oxides, which are obtained here through
high-accuracy linear-response time-dependent density functional theory
calculations. In particular, the macroscopic dielectric response functions
of both bulk CeO and CeO are derived, which compare
remarkably well with the available experimental data. These results stress the
importance of appropriately accounting for local field effects to model the
dielectric function of metal oxides. Furthermore, we reckon the materials
energy loss functions \mbox{Im} (-1/\bar{\epsilon}), including the accurate
evaluation of the momentum transfer dispersion from first-principles. In this
respect, by using a Mermin-type parametrization we are able to model the
contribution of different electronic excitations to the dielectric loss
function. Finally, from the knowledge of the electron inelastic mean free path,
together with the elastic mean free path provided by the relativistic Mott
theory, we carry out statistical Monte Carlo (MC) charge transport simulations
to reproduce the major features of the reported experimental reflection
electron energy loss (REEL) spectra of cerium oxides. The good agreement with
REEL experimental data strongly supports our approach based on MC modelling
informed by ab initio calculated electronic excitation spectra in a broad range
of momentum and energy transfers.Comment: 21 pages, 19 figure
SÃmbolos populares Colombianos
El presente proyecto de investigación está enfocado
a identificar los sÃmbolos populares colombianos que
gozan de una relevancia cultural en nuestro paÃs. Son
reconocidos pero poco explotados comercialmente,
ya que esto se puede evidenciar en aquellos objetos e
indumentaria que las personas llevan a diario. Nuestra
intencionalidad es tomar e intervenir representaciones
icónicas que guardan una aceptación y un acuerdo social
y estético en culturas como la nuestra, y se configuran
en el imaginario, para que desde lo simbólico puedan ser
comunicados desde el diseño y la comunicación gráfica
en una propuesta atractiva que le genere un sentido
de pertenencia a un grupo juvenil determinado, el cual
oscila entre 15 a 25 años
SÃmbolos populares Colombianos
El presente proyecto de investigación está enfocado
a identificar los sÃmbolos populares colombianos que
gozan de una relevancia cultural en nuestro paÃs. Son
reconocidos pero poco explotados comercialmente,
ya que esto se puede evidenciar en aquellos objetos e
indumentaria que las personas llevan a diario. Nuestra
intencionalidad es tomar e intervenir representaciones
icónicas que guardan una aceptación y un acuerdo social
y estético en culturas como la nuestra, y se configuran
en el imaginario, para que desde lo simbólico puedan ser
comunicados desde el diseño y la comunicación gráfica
en una propuesta atractiva que le genere un sentido
de pertenencia a un grupo juvenil determinado, el cual
oscila entre 15 a 25 años
Genetic study of atypical femoral fractures using exome sequencing in three affected sisters and three unrelated patients
Objectives: Atypical femoral fractures (AFF) are rare, often related to long-term bisphosphonate (BPs) tre- atment. Their pathogenic mechanisms are not precisely known and there is no evidence to identify patients with a high risk of AFF. The aim of this work is to study the genetic bases of AFFs. Material and methods: Whole-exome sequencing was carried out on 3 sisters and 3 unrelated additional patients, all treated with BPs for more than 5 years. Low frequency, potentially pathogenic variants sha- red by the 3 sisters, were selected, were selected and a network of gene and protein interactions was constructed with the data found. Results: We identified 37 rare variants (in 34 genes) shared by the 3 sisters, some not previously descri- bed. The most striking variant was the p.Asp188Tyr mutation in the enzyme geranylgeranyl pyrophos- phate synthase (encoded by the GGPS1 gene), from the mevalonate pathway and essential for osteoclast function. Another noteworthy finding was two mutations (one in the 3 sisters and one in an unrelated patient) in the CYP1A1 gene, involved in the metabolism of steroids. We identified other variants that could also be involved in the susceptibility to AFFs or in the underlying osteoporotic phenotype, such as those present in the SYDE2, NGEF, COG4 and FN1 genes. Conclusions: Our data are compatible with a model where the accumulation of susceptibility variants could participate in the genetic basis of AFFs
Twin digital short period seismic Array Experiment at Stromboli Volcano
Two small arrays composed by short period (1 Hz) digital seismic
stations, with an aperture of approximately 400 meters, were set up at
Stromboli volcano (one at semaforo Labronzo, the other at Ginostra-
Timpone del Fuoco) with the purpose of the spatial location of the high
frequency source of the explosion quakes.
About 75 explosion-quakes were recorded at both arrays, and
constitute the available data base.
We have planned to apply the zero-lag cross-correlation technique to
the whole data set in order to obtain back-azimuth and apparent
slowness of the coherent seismic phases. A preliminary analysis for
both arrays show that the predominant back-azimuth for the first phase
is oriented in the direction of , but not strictly coincident to, the crater
area. Moreover some back-scattered arrivals are quite evident in the
seismogram.INGV - Osservatorio VesuvianoUnpublishedope
Twin digital short period seismic Array Experiment at Stromboli Volcano
Two small arrays composed by short period (1 Hz) digital seismic
stations, with an aperture of approximately 400 meters, were set up at
Stromboli volcano (one at semaforo Labronzo, the other at Ginostra-
Timpone del Fuoco) with the purpose of the spatial location of the high
frequency source of the explosion quakes.
About 75 explosion-quakes were recorded at both arrays, and
constitute the available data base.
We have planned to apply the zero-lag cross-correlation technique to
the whole data set in order to obtain back-azimuth and apparent
slowness of the coherent seismic phases. A preliminary analysis for
both arrays show that the predominant back-azimuth for the first phase
is oriented in the direction of , but not strictly coincident to, the crater
area. Moreover some back-scattered arrivals are quite evident in the
seismogram
Stopping power and depth dose profile of H+ and He+ ion beams in hydroxyapatite thin films.
Hadron therapy is a promising technique to treat deep-seated tumors. For an accurate treatment planning, the energy deposition in the soft and hard human tissue must be well known. Water has been usually employed as a phantom of soft tissues, but other biomaterials, such as hydroxyapatite (HAp), used as bone substitute, are also relevant as a phantom for hard tissues. The stopping power of HAp for H+ and He+ beams has been studied experimentally and theoretically. The measurements have been done using the Rutherford backscattering technique in an energy range of 450-2000 keV for H+ and of 400-5000 keV for He+ projectiles. The theoretical calculations are based in the dielectric formulation together with the MELF-GOS (Mermin Energy-Loss Function – Generalized Oscillator Strengths) method [1] to describe the target excitation spectrum. A quite good agreement between the experimental data and the theoretical results has been found. The depth dose profile of H+ and He+ ion beams in HAp has been simulated by the SEICS (Simulation of Energetic Ions and Clusters through Solids) code [2], which incorporates the electronic stopping force due to the energy loss by collisions with the target electrons, including fluctuations due to the energy-loss straggling, the multiple elastic scattering with the target nuclei, with their corresponding nuclear energy loss, and the dynamical charge-exchange processes in the projectile charge state. The energy deposition by H+ and He+ as a function of the depth are compared, at several projectile energies, for HAp and liquid water, showing important differences.European Regional Development Fun
Genetic and Chemical Modifiers of a CUG Toxicity Model in Drosophila
Non-coding CUG repeat expansions interfere with the activity of human Muscleblind-like (MBNL) proteins contributing to myotonic dystrophy 1 (DM1). To understand this toxic RNA gain-of-function mechanism we developed a Drosophila model expressing 60 pure and 480 interrupted CUG repeats in the context of a non-translatable RNA. These flies reproduced aspects of the DM1 pathology, most notably nuclear accumulation of CUG transcripts, muscle degeneration, splicing misregulation, and diminished Muscleblind function in vivo. Reduced Muscleblind activity was evident from the sensitivity of CUG-induced phenotypes to a decrease in muscleblind genetic dosage and rescue by MBNL1 expression, and further supported by the co-localization of Muscleblind and CUG repeat RNA in ribonuclear foci. Targeted expression of CUG repeats to the developing eye and brain mushroom bodies was toxic leading to rough eyes and semilethality, respectively. These phenotypes were utilized to identify genetic and chemical modifiers of the CUG-induced toxicity. 15 genetic modifiers of the rough eye phenotype were isolated. These genes identify putative cellular processes unknown to be altered by CUG repeat RNA, and they include mRNA export factor Aly, apoptosis inhibitor Thread, chromatin remodelling factor Nurf-38, and extracellular matrix structural component Viking. Ten chemical compounds suppressed the semilethal phenotype. These compounds significantly improved viability of CUG expressing flies and included non-steroidal anti-inflammatory agents (ketoprofen), muscarinic, cholinergic and histamine receptor inhibitors (orphenadrine), and drugs that can affect sodium and calcium metabolism such as clenbuterol and spironolactone. These findings provide new insights into the DM1 phenotype, and suggest novel candidates for DM1 treatments
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