Impacto del Síndrome de Burnout Académico en el Bajo Rendimiento y la Salud Mental en Estudiantes Universitarios

El articulo reflexiona sobre la influencia del síndrome de burnout académico y su impacto en el promedio académico y la salud mental de un grupo de estudiantes de Ciencias de la Salud de una Universidad Privada del Caribe Colombiano. La población fueron estudiantes de Medicina, Odontología y Enfermería de una Universidad Privada de la ciudad de Santa Marta, Colombia, los Resultados evidenciaron que el 68% de los estudiantes presentaron promedio académico alto, el 25% medio y el 18% excelente. Se concluye que el síndrome de burnout académico, en particular el alto nivel de agotamiento emocional presente en los estudiantes, no afecta el promedio académico de los participantes, pero si puede alterar su salud mental

A Possible Crypto-Superconducting Structure in a Superconducting Ferromagnet

We have measured the dc and ac electrical and magnetic properties in various magnetic fields of the recently reported superconducting ferromagnet RuSr2GdCu2O8. Our reversible magnetization measurements demonstrate the absence of a bulk Meissner state in the compound below the superconducting transition temperature. Several scenarios that might account for the absence of a bulk Meissner state, including the possible presence of a sponge-like non-uniform superconducting or a crypto-superconducting structure in the chemically uniform Ru-1212, have been proposed and discussed.Comment: 8 pages, 5 PNG figures, submitted to Proceedings of the 9th Japan-US Workshop on High-Tc Superconductors, Yamanashi, Japan, October 13-15, 1999; accepted for publication in Physica C (December 24, 1999

Conductivity sum rule, implication for in-plane dynamics and c-axis response

Recently observed $c$-axis optical sum rule violations indicate non-Fermi liquid in-plane behavior. For coherent $c$-axis coupling, the observed flat, nearly frequency independent $c$-axis conductivity $\sigma_{1}(\omega)$ implies a large in-plane scattering rate $\Gamma$ around $(0,\pi)$ and therefore any pseudogap that might form at low frequency in the normal state will be smeared. On the other hand incoherent $c$-axis coupling places no restriction on the value of $\Gamma$ and gives a more consistent picture of the observed sum rule violation which, we find in some cases, can be less than half.Comment: 3 figures. To appear in PR

Microwave irradiation synthesis to obtain La0.7-xPrxCa0.3MnO3 perovskites : electrical and electrochemical performance

Atzin Ferrel is grateful for her grants from CONACYT and SIP- IPN. The authors also appreciate the financial support provided by the Consejo Nacional de Ciencia y Tecnología (CONACYT), México, Comisión de Operación y Fomento de Actividades Académicas del IPN (COFAA), México and Secretaría de Investigación y Posgrado (SIP) of the Instituto Politécnico Nacional (IPN) México through the CB2015–252181, 20201278, 20201279, 20201280, 20202443 and 20200909 projects as well as the SNI-CONACyT.La0.7-xPrxCa0.3MnO3 (LPCM) perovskites previously synthesized by the microwave-assisted method at 4 min and with different stoichiometry (x = 0.35, 0.52 and 0.63) were evaluated through thermogravimetric analysis (TGA), electrical conductivity, thermal expansion coefficient (TEC), scanning electron microscopy (SEM), Brunauer- Emmet- Teller (BET) analysis and electrochemical impedance spectroscopy (EIS) using yttria stabilized zirconia (YSZ) as an electrolyte. The results are discussed in terms of the potential as cathode material to be applied in solid oxide fuel cells (SOFCs) applications at temperatures from 600 to 800 °C. Results derived from TGA showed that Pr promotes the uncoupling oxygen and oxygen vacancies favoring the fuel combusting. Also, TEC analysis revealed adequate stability between the YSZ electrolyte and the La0.7-xPrxCa0.3MnO3 to avoid cracking or failing, especially with high amount of Pr. The transition in morphology from irregular to regular shapes improves the BET and Barret- Joyner- Halenda (BJH) surfaces and promotes the triple phase boundary (TPB) connectivity. The electrical conductivity correlated to the availability in oxygen vacancies showed maximum conductivities in the order of 10−2 S cm−1. Activation energy (Ea) was found to be reduced with a minimum quantity of Pr (0.071 eV). EIS results indicate that the oxygen vacancies in the LPCM/YSZ system were better promoted with the highest amount of Pr = 0.63 (η = 0.9 V, 800 °C and 0.06 V of amplitude) in comparison with the minimum, Pr = 0.35 (η = 1.2 V, 800 °C and 0.06 V of amplitude).PostprintPeer reviewe

Cavitation of Electrons Bubbles in Liquid Helium Below saturation Pressure

We have used a Hartree-type electron-helium potential together with a density functional description of liquid $^4$He and $^3$He to study the explosion of electron bubbles submitted to a negative pressure. The critical pressure at which bubbles explode has been determined as a function of temperature. It has been found that this critical pressure is very close to the pressure at which liquid helium becomes globally unstable in the presence of electrons. It is shown that at high temperatures the capillary model overestimates the critical pressures. We have checked that a commonly used and rather simple electron-helium interaction yields results very similar to those obtained using the more accurate Hartree-type interaction. We have estimated that the crossover temperature for thermal to quantum nucleation of electron bubbles is very low, of the order of 6 mK for $^4$He.Comment: 22 pages, 9 figure

Effect of structural defects on anomalous ultrasound propagation in solids during second-order phase transitions

The effect of structural defects on the critical ultrasound attenuation and ultrasound velocity dispersion in Ising-like three-dimensional systems is studied. A field-theoretical description of the dynamic effects of acoustic-wave propagation in solids during phase transitions is performed with allowance for both fluctuation and relaxation attenuation mechanisms. The temperature and frequency dependences of the scaling functions of the attenuation coefficient and the ultrasound velocity dispersion are calculated in a two-loop approximation for pure and structurally disordered systems, and their asymptotic behavior in hydrodynamic and critical regions is separated. As compared to a pure system, the presence of structural defects in it is shown to cause a stronger increase in the sound attenuation coefficient and the sound velocity dispersion even in the hydrodynamic region as the critical temperature is reached. As compared to pure analogs, structurally disordered systems should exhibit stronger temperature and frequency dependences of the acoustic characteristics in the critical region.Comment: 7 RevTeX pages, 4 figure

Anomalous fluctuations of the condensate in interacting Bose gases

We find that the fluctuations of the condensate in a weakly interacting Bose gas confined in a box of volume $V$ follow the law $\sim V^{4/3}$. This anomalous behaviour arises from the occurrence of infrared divergencies due to phonon excitations and holds also for strongly correlated Bose superfluids. The analysis is extended to an interacting Bose gas confined in a harmonic trap where the fluctuations are found to exhibit a similar anomaly.Comment: 4 pages, RevTe

Analytic structure factors and pair-correlation functions for the unpolarized homogeneous electron gas

We propose a simple and accurate model for the electron static structure factors (and corresponding pair-correlation functions) of the 3D unpolarized homogeneous electron gas. Our spin-resolved pair-correlation function is built up with a combination of analytic constraints and fitting procedures to quantum Monte Carlo data, and, in comparison to previous attempts (i) fulfills more known integral and differential properties of the exact pair-correlation function, (ii) is analytic both in real and in reciprocal space, and (iii) accurately interpolates the newest, extensive diffusion-Monte Carlo data of Ortiz, Harris and Ballone [Phys. Rev. Lett. 82, 5317 (1999)]. This can be of interest for the study of electron correlations of real materials and for the construction of new exchange and correlation energy density functionals.Comment: 14 pages, 5 figures, submitted to Phys. Rev.

FERMION ZERO MODES AND BLACK-HOLE HYPERMULTIPLETS WITH RIGID SUPERSYMMETRY

The gravitini zero modes riding on top of the extreme Reissner-Nordstrom black-hole solution of N=2 supergravity are shown to be normalizable. The gravitini and dilatini zero modes of axion-dilaton extreme black-hole solutions of N=4 supergravity are also given and found to have finite norms. These norms are duality invariant. The finiteness and positivity of the norms in both cases are found to be correlated with the Witten-Israel-Nester construction; however, we have replaced the Witten condition by the pure-spin-3/2 constraint on the gravitini. We compare our calculation of the norms with the calculations which provide the moduli space metric for extreme black holes. The action of the N=2 hypermultiplet with an off-shell central charge describes the solitons of N=2 supergravity. This action, in the Majumdar-Papapetrou multi-black-hole background, is shown to be N=2 rigidly supersymmetric.Comment: 18 pages, LaTe