2,019 research outputs found
Real-Time Propagation TDDFT and Density Analysis for Exciton Couplings Calculations in Large Systems
Photo-active systems are characterized by their capacity of absorbing light
energy and transforming it. Usually, more than one chromophore is involved in
the light absorption and excitation transport processes in complex systems.
Linear-Response Time-Dependent Density Functional (LR-TDDFT) is commonly used
to identify excitation energies and transition properties by solving well-known
Casida's equation for single molecules. However, this methodology is not useful
in practice when dealing with multichromophore systems. In this work, we extend
our local density decomposition method that enables to disentangle individual
contributions into the absorption spectrum to computation of exciton dynamic
properties, such as exciton coupling parameters. We derive an analytical
expression for the transition density from Real-Time Propagation TDDFT
(P-TDDFT) based on Linear Response theorems. We demonstrate the validity of our
method to determine transition dipole moments, transition densities and exciton
coupling for systems of increasing complexity. We start from the isolated
benzaldehyde molecule, perform a distance analysis for -stacked dimers and
finally map the exciton coupling for a 14 benzaldehyde cluster.Comment: 32 pages, 8 figures; added references in introductions, typos fixe
BUENAS PRÁCTICAS DE MANUFACTURA EN EL COMEDOR ESTUDIANTIL DE LA UNIVERSIDAD NACIONAL DE VILLA MARÍA: IMPACTOS SOBRE LA COMUNIDAD UNIVERSITARIA
El siguiente proyecto consiste en mejorar la calidad del servicio de alimentos del comedor universitario que posee la Universidad Nacional de Villa María (UNVM) y que impacta directamente sobre toda la comunidad universitaria y la sociedad en general que asiste al mismo. En los últimos años, ante el gran crecimiento de la cantidad de alumnos y con esto del cuerpo docente y no docente, las instalaciones del comedor quedaron con menor capacidad para atender a los comensales y además, tras el aumento de raciones diarias, se vio la necesidad de abordar el comedor desde la mirada de la calidad, la inocuidad alimentaria y de la salud social. Si bien, hasta la actualidad no se conoce que las universidades públicas de Argentina hayan certificado Buenas Prácticas de Manufactura en su comedor estudiantil, se ha tomado esto como un desafío. El proceso se realiza desde la Escuela Internacional de Negocios de la UNVM y en equipo junto a otras áreas como Secretaría de Bienestar, Secretaría de Planeamiento, Fundación de la UNVM, Vicerrectoría a Cargo del Rectorado y personal encargado del comedor. Los beneficios que traerá la presente certificación a la sociedad será: mejorar la calidad en la alimentación, mayor seguridad en la inocuidad de alimentos evitando intoxicaciones e infecciones por incorrecta manipulación e higiene en los alimentos, personal de cocina más capacitado en higiene, vestimenta personal y atención al público, servicio de comida caliente evitando el recalentamiento de los alimentos y sobre todo una mejor calidad de servicio en todos sus aspectos, atención, calidad de alimentos, higiene, infraestructura, entre otros
Design of Scales to Assess the subjective social value of education for students in primary and secondary school.
The devaluation of education, related with multiple socio-economic and psycho-school factors may be influencing decisively on academic results. A target level is observed that the socio-economic and cultural level of families can decide the student performance, however, this international trend shows inconsistent results. In addition, in different studies, we can observe that students from disadvantaged backgrounds statistics exceed expectations in performance, surpassing the expected results depending on their socioeconomic and cultural level; and students should achieve optimal results for their family situation do not get the expected performance. An interpretative hypothesis may be that subjective social value given to education is a factor which explains these results. Such situations could be analyzed at the macro level assessment indicators that identify patterns of social and school projection given to education. Thus, from a framework of systemic research based on an evaluation model aimed at identifying the contributions of education as a means for the development of social cohesion, has worked through expert committees and work groups with 60 teachers (school, high school and college) to assess the adequacy, clarity and absence of bias on a proposed scale on the Subjective Social Value of Education. To analyze factors among students in primary and secondary education to help overcome these situations of inequality and help improve the situation for all students. Suitable results are detected and two scales of 20 items each: primary and secondary are presented. As prospectively the intention is to validate and debug to metric level (Classical Theory of Tests and Item Response Theory) to ensure her quality and application in future researches
Some notes to extend the study on random non-autonomous second order linear differential equations appearing in Mathematical Modeling
The objective of this paper is to complete certain issues from our recent
contribution [J. Calatayud, J.-C. Cort\'es, M. Jornet, L. Villafuerte, Random
non-autonomous second order linear differential equations: mean square analytic
solutions and their statistical properties, Advances in Difference Equations,
2018:392, 1--29 (2018)]. We restate the main theorem therein that deals with
the homogeneous case, so that the hypotheses are clearer and also easier to
check in applications. Another novelty is that we tackle the non-homogeneous
equation with a theorem of existence of mean square analytic solution and a
numerical example. We also prove the uniqueness of mean square solution via an
habitual Lipschitz condition that extends the classical Picard Theorem to mean
square calculus. In this manner, the study on general random non-autonomous
second order linear differential equations with analytic data processes is
completely resolved. Finally, we relate our exposition based on random power
series with polynomial chaos expansions and the random differential transform
method, being the latter a reformulation of our random Fr\"obenius method.Comment: 15 pages, 0 figures, 2 table
Toward End-to-End, Full-Stack 6G Terahertz Networks
Recent evolutions in semiconductors have brought the terahertz band in the
spotlight as an enabler for terabit-per-second communications in 6G networks.
Most of the research so far, however, has focused on understanding the physics
of terahertz devices, circuitry and propagation, and on studying physical layer
solutions. However, integrating this technology in complex mobile networks
requires a proper design of the full communication stack, to address link- and
system-level challenges related to network setup, management, coordination,
energy efficiency, and end-to-end connectivity. This paper provides an overview
of the issues that need to be overcome to introduce the terahertz spectrum in
mobile networks, from a MAC, network and transport layer perspective, with
considerations on the performance of end-to-end data flows on terahertz
connections.Comment: Published on IEEE Communications Magazine, THz Communications: A
Catalyst for the Wireless Future, 7 pages, 6 figure
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