Critical behavior of ferromagnetic pure and random diluted nanoparticles with competing interactions: variational and Monte Carlo approaches

The magnetic properties and critical behavior of both ferromagnetic pure and metallic nanoparticles having concurrently atomic disorder, dilution and competing interactions, are studied in the framework of an Ising model. We have used both the free energy variational principle based on the Bogoliubov inequality and Monte Carlo simulation. As a case of study for random diluted nanoparticles we have considered the Fe$_{0.5}$Mn$_{0.1}$Al$_{0.4}$ alloy characterized for exhibiting, under bulk conditions, low temperature reentrant spin glass (RSG) behavior and for which experimental and simulation results are available. Our results allow concluding that the variational model is successful in reproducing features of the particle size dependence of the Curie temperature for both pure and random diluted particles. In this last case, low temperature magnetization reduction was consistent with the same type of RSG behavior observed in bulk in accordance with the Almeida-Thouless line at low fields and a linear dependence of the freezing temperature with the reciprocal of the particle diameter was also obtained. Computation of the correlation length critical exponent yielded the values $\nu=0.926\pm 0.004$ via Bogoliubov and$\nu =0.71\pm 0.04$ via Monte Carlo. This fact indicates that even though thermodynamical models can be indeed used in the study of nanostructures and they can reproduce experimental features, special attention must be paid regarding critical behavior. From both approaches, differences in the $\nu$ exponent with respect to the pure Ising model agree with Harris and Fisher arguments.Comment: 11 pages, 11 figures. Submitted to Phys. Rev.

Induction of stimulative parthenocarpy in Vitis vinifera L.

Stimulative parthenocarpy was induced in two varieties of Vitis vinifera L. Flame Tokay and Rose Muscat (local variety) out of eight varieties studied.In F l a m e T o k a y the delay or inhibition of bhe abscission of the calyptra and parthenocarpic development of the berries, was obtained with pre-bloom treatments (3 days before beginning of bloom) of 4CPA 30 ppm + KGA3 30 ppm. Induction and growth ,of parthenocarpic berries was most pronounced after post-bloom sprays (7 days after the end of bloom) with BA 1500 ppm + KGA3 80 ppm or 4CPA 30 ppm. A parthenocarpic development of the berries was also obtained with postbloom treatments of KGA3 at concentrations of 50 to 100 ppm. BA (Benzyladenine) alone had only a slight effect on the development of parthenocarpic berries. However, the results were surprisingly satisfactory when applied in combination with gibberellin (KGA3 80 ppm) or auxins. Treatments at bloom or after bloom with BA 800 ppm + KGA3 80 ppm increased bhe number of berries and cluster weight. Applications of BA 800 ppm + KGA3 80 ppm to Rose Musca t at the beginning of bloom resulted in clusters with practically all berries seedless. The artificially accelerated growth of the berries may provoke abortion of all the recently fecundated ovules and the non viability of the not fecundated ones. Clusters of the treated plants with an average of 520 flowers originated 501 parbhenocarpic berries (96%), whereas the control with an average 635 flowers per cluster gave a percentage of seeded + seedless berries of 14% only {95 berries per cluster). BA applied with auxin or gibberellin-like substances in full-bloom or after bloom produced seedless berries, which were smaller in size than the seeded berries of unsprayed clusters

Analysis of the start to the first hurdle in 110m hurdles at the IAAF World Athletics Championships Beijing 2015

The purpose of this study was to use observational analysis to evaluate the relationships between variables measured at the start of the men’s 110 hurdles event and race performance itself. Data were obtained for competitors in 2015 IAAF World Athletics Ch ampionships, in Beijing, China. The athletes’ start was quantified by reaction time and time to the first hurdle; their action over the first hurdle was quantified by the take - off distance (i.e., the distance from the last step to the first hurdle), the la nding distance, and the total distance in the air over the first hurdle. Regression analyses revealed that the combination of one measure of the start (either reaction time or time to the first hurdle) and the measure of propulsion over the first hurdle (d istance in air over the first hurdle) predicted performance (SEE = 0.23 s in the heats, SEE = 0.16 s in the semi - finals, SEE = 0.09 s in the finals). In addition, looking at performances in the finals, where all athletes with available data used a seven - st ep approach to the first hurdle, inclusion of stride length data improved the prediction somewhat (SEE = 0.07 s). The results demonstrate that a combination of a fast start, rapid acceleration, and strong drive over the first hurdle quantifiably explains a nd contributes to performance in the men’s 110 m hurdles at the highest level

Un registro de hipertrofia del trago del murciélago frugívoro de gran tamaño Artibeus lituratus (Chiroptera: Phyllostomidae)

In this work, we report and describe evidence of an anomaly in the tragus of an individual of Artibeus lituratus, captured in the Central Andes of Colombia. During field work in the Department of Caldas, municipality of Aranzazu, one individual of A. lituratus with unusual tragus form was trapped. This individual had a tragus with cylindrical shape and asymmetry. The individual was collected and deposited at the Museum of Natural History of the University of Caldas (MHN-UCa). A literature review was conducted to find similar cases using searching engines, but no previous reports of the anomaly were find. Furthermore, we reviewed the tragus of vouchers at the MHN-UCa and none of these had similar malformations. We concluded that this anomaly has not previously registered in Chiroptera.En este trabajo, reportamos y describimos evidencia de una anomalía en el trago de un individuo de Artibeus lituratus, capturado en los Andes Centrales de Colombia. En junio de 2019, durante un trabajo de campo en el Departamento de Caldas, municipio de Aranzazu, quedó atrapado un individuo de A. lituratus con inusual forma de trago. Este individuo tenía un trago de forma cilíndrica y asimetría. El individuo fue recogido y depositado en el Museo de Historia Natural de la Universidad de Caldas (MHN-UCa). Se realizó una revisión de la literatura para encontrar casos similares utilizando motores de búsqueda, pero no se encontraron informes previos de la anomalía. Además, revisamos el trago de los especímenes en el MHN-UCa y ninguno de ellos presentaba malformaciones similares. Concluimos que esta anomalía no se había registrado previamente en Chiroptera

Analysis Gender Stereotypes in perception profile of conduct in track and field

In our current world, the existance of obstacles to acknowledge women’s equal abiliAes is real. Legally there are no barriers. The Sports Act of the government of Andalusia (Law 5/2016, July 19) determines the right to equality between genders. This is what has been called the glass ceiling. Gender stereotypes about behavior profile recreate constraints that occur in everyday pracAces, power relaAons and insAtuAonal arrangements of the general social order. Thee stereotypes are rooted in sports. In this sense. The objecAve of this study was to "interprete different gender stereotypes that exist regarding men’s and women’s profile of conduct in athleAcs.

Detección de hemoglobinopatía c: un caso de interacción interalélica

Estudios en Colombia revelan una alta frecuencia de hemoglobinopatías (1, 2, 3, 4), con una frecuencia para hemoglobinopatía C de 1.4% y en combinación con otras variables 0.33%, esto constituye un problema de salud pública según la OMS. La forma heterocigota con frecuencia es asintomática y la homocigota presenta anemia de moderada severidad