1,125 research outputs found
All-optical 3D atomic loops generated with Bessel light fields
The propagation invariance of Bessel beams as well as their transversal
structure are used to perform a comparative analysis of their effect on cold
atoms for four different configurations and combinations thereof. We show that,
even at temperatures for which the classical description of the atom center of
mass motion is valid, the interchange of momentum, energy and orbital angular
momentum between light and atoms yields efficient tools for all-optical
trapping, transporting and, in general, manipulating the state of motion of
cold atoms.Comment: 13 pages, 9 figure
Sharp values for the constants in the polynomial Bohnenblust-Hille inequality
In this paper we prove that the complex polynomial Bohnenblust-Hille constant
for -homogeneous polynomials in is exactly
. We also give the exact value of the real polynomial
Bohnenblust-Hille constant for -homogeneous polynomials in .
Finally, we provide lower estimates for the real polynomial Bohnenblust-Hille
constant for polynomials in of higher degrees.Comment: 16 page
Burnout syndrome prevalence in veterinarians working in Chile
Burnout Syndrome is a psycho-emotional syndrome that affects workers in any activity or profession. In recent years, veterinarians have been described as one of the most affected professionals, which has motivated the development of this research. The primary objective of this work was to determine the prevalence of Burnout Syndrome in veterinarians working in Chile. We evaluated the possible correlation of Burnout Syndrome with socio-demographic variables. The Socio-Demographic Characterization Survey and the Maslach Burnout Syndrome Inventory-General Survey (MBI) were applied to 521 participants, who were contacted through the Veterinary Medical Association of Chile (COLMEVET) and social networks. Fisher and Chi-square statistical tests and correspondence analysis were used to determine the association among variables. The prevalence of Burnout Syndrome in Chilean veterinarians was 24% (124/521). There was statistical significance between Burnout Syndrome and the variables âyears in employmentâ and âmonthly salaryâ. There is a high prevalence of Burnout Syndrome in veterinarians working in Chile that was related to the variables âyears in employmentâ and âmonthly salaryâ. Prevention using psychological therapy could reduce the incidence of symptoms linked to adaptive difficulties, cognitive discrepancies, psychological discomfort, and emotional regulation, promoting health improvement and resistance to Burnout Syndrome in Chilean veterinarians. This research corresponds to the first exploratory study related to the subject in Chil
Evaluation of the introduction of electric vehicles in the power grid â a study for the island of Maio in Cape Verde
Serie: Lecture notes in electrical engineering, vol. 402This paper presents an evaluation of the introduction of electric vehi-cles (EVs) in an electrical power grid. The main contribution is the control analysis of the power quality considering simultaneous battery charging pro-cesses. The methodology used can be applied to any known power grid; howev-er, it was considered the case of the island of Maio, in Cape Verde, in continua-tion of previous works concerning that power grid. Two commercial different types of battery chargers were considered: a traditional model with highly dis-torted current consumption (that causes distortion in the power grid voltage), and another with almost sinusoidal current consumption. Considering simulta-neous battery charging processes, it can be concluded that the power grid struc-ture (composed by three medium voltage branches) with the current power de-mands of the consumers of the island of Maio have a potential integration for 300 EVs if battery chargers with almost sinusoidal current consumption are used, i.e., 152 for the first medium voltage branch, 35 for the second branch, and 113 for the third branch. Moreover, the results show that the first medium voltage branch of the distribution system, which has the capability to support the integration of 152 EVs if the battery chargers have sinusoidal current con-sumption (presenting a maximum value of THDv% in the power grid voltage of 1.8%), only can support 27 EVs if are used traditional battery chargers, with highly distorted current consumption (considering a maximum THDv% of 5%).COMPETE: POCI-01-0145-FEDER-007043Fundação para a CiĂȘncia e Tecnologia (FCT) - UID/CEC/00319/2013Fundação para a CiĂȘncia e Tecnologia (FCT) - SFRH/BD/80155/201
Chaos and Noise in a Truncated Toda Potential
Results are reported from a numerical investigation of orbits in a truncated
Toda potential which is perturbed by weak friction and noise. Two significant
conclusions are shown to emerge: (1) Despite other nontrivial behaviour,
configuration, velocity, and energy space moments associated with these
perturbations exhibit a simple scaling in the amplitude of the friction and
noise. (2) Even very weak friction and noise can induce an extrinsic diffusion
through cantori on a time scale much shorter than that associated with
intrinsic diffusion in the unperturbed system.Comment: 10 pages uuencoded PostScript (figures included), (A trivial
mathematical error leading to an erroneous conclusion is corrected
An integrated project of entrepreneurship and innovation in engineering education
This paper presents a new line of project based learning in the School of Engineering of University of Minho:
the Innovation and Entrepreneurship Integrated Project (IEIP). Four groups, each one composed of
students from different engineering integrated master courses â Mechanical, Industrial Electronics and
Computers, Polymer, Industrial Management â compete against each other in developing or improving
commercial products manufactured by actual industries. There have been so far five editions of the IEIP,
with five different companies and five diverse products, however, all these products included components
that required knowledge from all the engineering courses involved. Only with the cooperation
between the students of the various courses that compose each multidisciplinary team, the success is
attainable. As each student has to deal with various engineering scopes, studentsâ technical skills are
greatly enlarged and they acquire a multidisciplinary knowledge that was not possible in another way.
Their soft skills like project management, teamwork, communication ability and personal development,
which are valuable requisites for their future employers, are also improved. The participating industries
also take advantage of the project: the groups competing against each other act as a multiskilled work
force, actually making proposals capable of improving their products, their efficiency, and reducing costs
Online dating in times of COVID-19: usage practices and communicational dynamics in forced transformation
As plataformas de online dating, que progressivamente se tĂȘm multiplicado e migrado do formato website para o de aplicação mĂłvel e crescido em nĂșmero de utilizadores, oferecem uma crescente variedade e multiplicidade de formas de socialização, que se desdobra, tipicamente, em trĂȘs etapas: construção de perfil, correspondĂȘncia com outros utilizadores e descoberta.
Mesmo que os seus utilizadores procurem mais do que relacionamentos ou sexo, a pandemia de COVID-19 e consequentes limitaçÔes, em especial distanciamento social fĂsico e confinamentos, veio alterar os pressupostos do seu funcionamento e a forma como os utilizadores interagem, nomeadamente pela impossibilidade da descoberta mĂștua migrar para encontros presenciais.
Nesse sentido procurou investigar-se trĂȘs grandes dimensĂ”es de anĂĄlise ancoradas ao contexto nacional: 1) como Ă© que os utilizadores reagiram, em termos de comportamentos e hĂĄbitos de consumo, Ă s alteraçÔes provocadas pela pandemia, 2) como as plataformas se adaptaram e 3) que atenção foi dada pelos media Ă s transformaçÔes do online dating. Para responder Ă s questĂ”es analisou-se de forma triangulada o consumo dos utilizadores, a comunicação e evolução das plataformas e a atenção dos media, numa anĂĄlise mista (quantitativa e qualitativa) realizada com recurso a mĂ©todos e ferramentas digitais de extração, organização e anĂĄlise, e a dados secundĂĄrios.
Os principais resultados apontam para a COVID-19 como variåvel importante em alteraçÔes registadas na construção de perfis e håbitos de consumo por parte dos utilizadores, e dos serviços das plataformas, tanto em termos de conselhos e sugestÔes como de novas funcionalidades. Os media portugueses focaram também a sua atenção no online dating nas novidades adaptativas em termos de ofertas e tecnologias, e no questionamento da sua utilização em tempos de pandemia.info:eu-repo/semantics/publishedVersio
A new class of semiclassical wave function uniformizations
We present a new semiclassical technique which relies on replacing
complicated classical manifold structure with simpler manifolds, which are then
evaluated by the usual semiclassical rules. Under circumstances where the
original manifold structure gives poor or useless results semiclassically the
replacement manifolds can yield remarkable accuracy. We give several working
examples to illustrate the theory presented here.Comment: 12 pages (incl. 12 figures
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