203 research outputs found
Transient features of quantum open maps
We study families of open chaotic maps that classically share the same
asymptotic properties -- forward and backwards trapped sets, repeller
dimensions, escape rate -- but differ in their short time behavior. When these
maps are quantized we find that the fine details of the distribution of
resonances and the corresponding eigenfunctions are sensitive to the initial
shape and size of the openings. We study phase space localization of the
resonances with respect to the repeller and find strong delocalization effects
when the area of the openings is smaller than .Comment: 7 pages, 7 figure
Numerical validation of the Complex Swift-Hohenberg equation for lasers
Order parameter equations, such as the complex Swift-Hohenberg (CSH)
equation, offer a simplified and universal description that hold close to an
instability threshold. The universality of the description refers to the fact
that the same kind of instability produces the same order parameter equation.
In the case of lasers, the instability usually corresponds to the emitting
threshold, and the CSH equation can be obtained from the Maxwell-Bloch (MB)
equations for a class C laser with small detuning. In this paper we numerically
check the validity of the CSH equation as an approximation of the MB equations,
taking into account that its terms are of different asymptotic order, and that,
despite of having been systematically overlooked in the literature, this fact
is essential in order to correctly capture the weakly nonlinear dynamics of the
MB. The approximate distance to threshold range for which the CSH equation
holds is also estimated.Comment: submitted to European Journal of Physic
Assessment of the use of technical software by the students in the context of mechanical engineering
[EN] In the framework of the European Higher Education area, university teaching has focused in recent years on adapting Master's and Bachelor's degrees to the demands of the professional sector. To do this, the training and development of the generic and specific skills recommended for the incorporation of students into the job market have been priority objectives in the approach to study plans. However, there is no consensus on the methodologies for evaluating these skills, especially regarding how to separate the acquisition and / or improvement of the skills from the specific knowledge and skills of the subjects. Due to the lack of time, teaching staff seek methodologies that do not involve additional tests for the evaluation of competences, which would increase the number of tests to a non-realistic number with the corresponding assessment duties for the professors.
In order to make a contribution in this regard, this work presents an approach for evaluating the ability to handle specific software applied to problems in the area of mechanical engineering. This work proposes a methodology for acquiring the required skills and an evaluation system to grade the degree of expertise in the manipulation of the software. In our University, this skill is called the Specific Instrumental Skill, which measures the ability of the students for using the tools in engineering, like, in this case, the use of software to run structural numerical simulations as ANSYS®.
The methodology proposed is based on an a priori training. This training is based on 2 hours weekly sessions where the students should solve, in groups of 2 or 3 students, a set of labs with the help of the professor. The students do not need to deliver any report to the professor since the objective of the sessions is the training of the students. Therefore, the pressure over the student is low and the professor avoid to mark a high number of student¿s reports, allowing him to focus only on the learning process of the students and not on the evaluation during the training sessions. These labs increase the difficulty along a number of sessions. The last session consists in an exam in which the students must solve a lab similar to those already solved during the training sessions. This time, each student will work individually without the help of the professor and with a control of the time.
Finally, the performance of the methodology is checked by a cross-test for the same students who are part of the group of students of another subject (control subject) where the same tool (ANSYS®) is used. The collected data showed that the students following this methodology acquire the sufficient expertise for handling the software and their skills outperform those of the students of the control subject who did not follow the proposed methodology.
As a conclusion, the methodology proposed in this work guarantees a good level of expertise for the students, as shown by the results. Since the results in the final lab exam and the results of the cross-test coincides, the use of the final test exam could be interpreted as a good indicator of the degree of expertise in the use of the software. Additionally, the proposed methodology reduces the work load for the professor as it only requires assessing 1 report per student (instead of several reports for each group of 2 or 3 students in each of the session) while ensuring the authorship of the report.Authors gratefully acknowledge the financial support of the Vicerrectorado de Estudios, Calidad y
Acreditación and the Vicerrectorado de Recursos Digitales y Documentación of the Universitat
Politècnica de València (project PIME B/19-20/165) and the Instituto de Ciencias de la Educación of
the Universitat Politècnica de València (EICE INTEGRAL).Nadal, E.; Rupérez Moreno, MJ.; Giner Navarro, J.; Rovira, A.; Ródenas, JJ.; Martínez Casas, J.; Pedrosa, AM. (2020). Assessment of the use of technical software by the students in the context of mechanical engineering. IATED Academy. 3344-3348. https://doi.org/10.21125/iceri.2020.0756S3344334
L’atenció primerenca a les Illes Balears
El treball descriu el programa d’atenció primerenca que es desenvolupa a les Illes Balears, la seva evolució, els professionals i les seves funcions en cada un dels àmbits implicats. Per altra part, també s’ofereixen dades sobre la població atesa. Els autors són professionals dels tres àmbits responsables del Pla integral d’atenció primerenca de les Illes Balears (educatiu, sanitari i social), els quals destaquen la importància de la coordinació interdisciplinària i la necessitat de disposar d’una xarxa de serveis que doni resposta a les necessitats dels infants i les seves famílies.El trabajo describe el programa de atención primaria que se desarrolla en las Islas Baleares, su evolución, los profesionales y sus funciones en cada uno de los ámbitos implicados. Por otra parte, también se ofrecen datos sobre la población atendida. Los autores son profesionales de los tres ámbitos responsables del Plan integral de atención primaria de las Islas Baleares (educativo, sanitario y social), los cuales destacan la importancia de la coordinación interdisciplinar y la necesidad de disponer de una red de servicios que den respuesta a las necesidades de los niños y sus familias
Disruption of striatal glutamatergic transmission induced by mutant huntingtin involves remodelling of both postsynaptic density and NMDA receptor signalling
We study the striatal susceptibility to NMDA receptor (NMDAR)-mediated injury of two Huntington’s disease (HD) transgenic mice:R6/1 and R6/1:BDNF+/−. We found that R6/1:BDNF+/− mice – whichexpress reduced levels of BDNF – were more resistant than R6/1 miceto intrastriatal injection of quinolinate. This increased resistance isrelated to a differential reduction in expression of NMDAR scaffoldingproteins, MAGUKs (PSD-95, PSD-93, SAP-102 and SAP-97) but notto altered levels or synaptic location of NMDAR. A robust reorganizationof postsynaptic density (PSD) was detected in HD transgenicmice, shown by a switch of PSD-93 by PSD-95 in PSD. Furthermore,NMDAR signaling pathways were affected by different BDNF levels inHD mice; we found a reduction of synaptic αCaMKII (but not ofnNOS) in R6/1:BDNF+/− compared to R6/1 mice. The specific regulationof MAGUKs and αCaMKII in striatal neurons may reflect aprotective mechanism against expression of mutant huntingtin exon-1
Room Temperature In-plane <100> Magnetic Easy Axis for Fe3O4/SrTiO3(001):Nb Grown by Infrared PLD
We examine the magnetic easy-axis directions of stoichiometric magnetite
films grown on SrTiO3:Nb by infrared pulsed-laser deposition. Spin-polarized
low-energy electron microscopy reveals that the individual magnetic domains are
magnetized along the in-plane film directions. Magneto-optical Kerr
effect measurements show that the maxima of the remanence and coercivity are
also along in-plane film directions. This easy-axis orientation differs
from bulk magnetite and films prepared by other techniques, establishing that
the magnetic anisotropy can be tuned by film growth.Comment: 3 pages, 3 figure
Distribution of resonances in the quantum open baker map
We study relevant features of the spectrum of the quantum open baker map. The
opening consists of a cut along the momentum direction of the 2-torus phase
space, modelling an open chaotic cavity. We study briefly the classical forward
trapped set and analyze the corresponding quantum nonunitary evolution
operator. The distribution of eigenvalues depends strongly on the location of
the escape region with respect to the central discontinuity of this map. This
introduces new ingredients to the association among the classical escape and
quantum decay rates. Finally, we could verify that the validity of the fractal
Weyl law holds in all cases.Comment: 6 pages, 7 figures, accepted for publication in Phys. Rev.
MOF-Based Materials with Sensing Potential: Pyrrolidine-Fused Chlorin at UiO-66(Hf) for Enhanced NO2 Detection
An efficient strategy to develop porous materials with potential for NO2 sensing was based in the preparation of a metal-organic framework (MOF), UiO-66(Hf), modified with a very small amount of meso-tetrakis(4-carboxyphenyl) N-methylpyrrolidine-fused chlorin (TCPC), TCPC@MOF. Chlorin’s incorporation into the UiO-66(Hf) framework was verified by several characterization methods and revealed that the as-synthesized TCPC@MOF brings together the chemical stability of UiO-66(Hf) and the photophysical properties of the pyrrolidine-fused chlorin which is about five times more emissive than the porphyrin counterpart. TCPC@MOF was further incorporated into polydimethylsiloxane (PDMS) and the resulting TCPC@MOF@PDMS film was tested in NO2 gas sensing. It showed notable sensitivity as well as a fast response in the range between 0.5 and 500 ppm where an emission intensity quenching is observed up to 96% for 500 ppm. This is a rare example of a chlorin-derivative used for gas-sensing applications through emission changes, and an unusual case of this type of optical-sensing composites of NO2.FCT-MCTE
Boosting antimicrobial activity of ciprofloxacin by functionalization of mesoporous silica nanoparticles
Mesoporous silica nanoparticles (MSNs) are very promising nanomaterials for treating bacterial infections when combined with pharmaceutical drugs. Herein, we report the preparation of two nanomaterials based on the immobilization of ciprofloxacin in mesoporous silica nanoparticles, either as the counter-ion of the choline derivative cation (MSN-[Ch][Cip]) or via anchoring on the surface of amino-group modified MSNs via an amide bond (MSN-Cip). Both nanomaterials were characterized by TEM, FTIR and solution 1H NMR spectroscopies, elemental analysis, XRD and N2 adsorption at 77 K in order to provide the desired structures. No cytotoxicity from the prepared mesoporous nanoparticles on 3T3 murine fibroblasts was observed. The antimicrobial activity of the nanomaterials was determined against Gram-positive (Staphylococcus aureus and Bacillus subtilis) and Gram-negative (Klebsiella pneumoniae) bacteria and the results were promising against S. aureus. In the case of B. subtilis, both nanom aterials exhibited higher antimicrobial activity than the precursor
[Ch][Cip], and in the case of K. pneumoniae they exhibited higher activity than neutral ciprofloxacin.info:eu-repo/semantics/publishedVersio
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