Modelo para el análisis de una aptitud cognitiva para el aprendizaje

La investigación en el campo de las aptitudes cognitivas para el aprendizaje requiere una forma de abordarlas y definir sus características y componentes. A su vez, esta definición debe conducir al investigador a la creación de pruebas de medición que ayuden al análisis de este tipo de aptitudes y su relación con otras variables del aprendizaje. Para dar respuesta a esas necesidades, el objetivo de este artículo es proponer la creación de un modelo para el análisis de una aptitud cognitiva para el aprendizaje, cuya estructura conste de cuatro elementos principales. Dos de ellos relacionados con los enfoques y consideraciones para emprender su estudio; los otros dos, con la definición de la aptitud, a través de sus características y sus componentes

Causas célebres. Crimen y liberalismo en la prensa mexicana del siglo XIX

En la prensa de la Ciudad de México durante el periodo que abarca desde principios del siglo XIX hasta la segunda década del Porfiriato fueron publicadas las denominadas causas célebres, relatos de crímenes de la época, que constituyen un género entre el periodismo y la literatura popular, las cuales se articulan como testimonio de la transformación del discurso sobre el crimen realizado por las élites mexicanas, en especial las adscritas al liberalismo. En el presente trabajo se realiza un análisis de los elementos que el discurso liberal dentro de las causas célebres emplea para interpretar el crimen y configurarlo en el imaginario social, en particular en La causa contra los asesinos de Florencio Egerton y Doña Inés Edwards cuyo seguimiento fue dado por diarios como El Observador judicial y El Siglo Diez y Nueve (cuyo nombre fue El Memorial Histórico de 1842 a 1843

Chiralities of nodal points along high symmetry lines with screw rotation symmetry

Screw rotations in nonsymmorphic space group symmetries induce the presence of hourglass and accordion shape band structures along screw invariant lines whenever spin-orbit coupling is nonnegligible. These structures induce topological enforced Weyl points on the band intersections. In this work we show that the chirality of each Weyl point is related to the representations of the cyclic group on the bands that form the intersection. To achieve this, we calculate the Picard group of isomorphism classes of complex line bundles over the 2-dimensional sphere with cyclic group action, and we show how the chirality (Chern number) relates to the eigenvalues of the rotation action on the rotation invariant points. Then we write an explicit Hamiltonian endowed with a cyclic action whose eigenfunctions restricted to a sphere realize the equivariant line bundles described before. As a consequence of this relation, we determine the chiralities of the nodal points appearing on the hourglass and accordion shape structures on screw invariant lines of the nonsymmorphic materials PI3 (SG: P63), Pd3N (SG: P6322), AgF3 (SG: P6122) and AuF3 (SG: P6122), and we corroborate these results with the Berry curvature and symmetry eigenvalues calculations for the electronic wavefunction.Comment: 10 pages, 4 figure

Seguridad hospitalaria, una visión de seguridad multidimensional: Hospital security. A vision of multidimensional security

The risks during the performance of work is an inherent situation to any human activity. Hospital Safety is defined as: “the condition that guarantees that the workers, patients, visitors, infrastructure and equipment within a health care center are free of risk or danger of accidents”. The construction of the prevention culture starts from the knowledge of the risks, the safety culture is directly related to the quality of care of the service provided, which is why these terms are of special interest in health institutions. Talking about comprehensive risk management, either, involves determining all the risks that could cause considerable damage to these systems, given by the interaction of three factors, the presence of a threat, the existence of vulnerabilities and the time they are exposed to. Thus we can distinguish that hospital safety must be an internal policy of every health institution and that it can be divided into three main axes: 1. Patient safety, 2. Comprehensive risk management for major emergencies and disasters, 3. Internal safety and external to violence.Los riesgos durante el desempeño del trabajo es una situación inherente a cualquier actividad humana. La Seguridad Hospitalaria se define como: “la condición que garantiza que los trabajadores, pacientes, visitantes, infraestructura y equipos dentro de un centro de atención en salud, estén libres de riesgo o peligro de accidentes”. La construcción de la cultura de prevención parte del conocimiento de los riesgos, la cultura de la seguridad se encuentra directamente relacionada con la calidad de atención del servicio que se otorga, por lo cual en las instituciones de salud estos términos son de especial interés. Hablar de gestión integral de riesgos implica determinar todos los riesgos que pudieran provocar un daño considerable a estos sistemas, dado por la interacción de tres factores, la presencia de una amenaza, la existencia de vulnerabilidades y el tiempo a exposición a estos. Así podemos distinguir que la seguridad hospitalaria debe ser una política interna de toda institución de salud y que se puede dividir en tres grandes ejes: 1. Seguridad del paciente, 2. Gestión integral de riesgos de emergencias mayores y desastres, 3. Seguridad interna y externa ante violencia

Quasinodal lines in rhombohedral magnetic materials

A well-established result in condensed matter physics states that materials crystallizing in symmetry groups containing glide reflection symmetries possess nodal lines on the energy bands. These nodal lines are topologically protected and appear on the fixed planes of the reflection in reciprocal space. In the presence of inversion symmetry, the energy bands are degenerate and the band crossings on the fixed plane may be one-dimensional, or may intersect in points, including the case of empty intersection. In the latter case, the crossing is partially or totally avoided, thus producing lines on reciprocal space where the energy gap may be small, and in the former, the nodal lines will endure, thus producing Dirac or double nodal lines. In addition, if the material crystallizes in a ferromagnetic phase where the glide reflection symmetry is broken, the nodal lines hybridize, thus defining lines in reciprocal space where the energy gap may be small. In this work, we concentrate our efforts on the study of nodal lines that hybridize due to magnetization; we have coined the term of quasinodal lines for those lines in reciprocal space where the energy gap is small (less than what can be detected experimentally ∼25 meV). We study magnetic trifluorides and trioxides which crystallize in magnetic space groups 167.107 and 161.71 and we show the existence of quasinodal lines on these materials. We furthermore show that whenever the quasinodal lines are located around the Fermi level then interesting charge and spin transport effects are induced and can be used to detect experimentally these lines. Of particular interest are the half-metallic ferromagnetic phases of PdF3 and LiCuF3 where the large signal of the anomalous Hall conductance is due to the presence of the quasinodal lines on the Fermi level

Topological electronic structure and Weyl points in nonsymmorphic hexagonal materials

Using topological band theory analysis we show that the nonsymmorphic symmetry operations in hexagonal lattices enforce Weyl points at the screw-invariant high-symmetry lines of the band structure. The corepresentation theory and connectivity group theory show that Weyl points are generated by band crossings in accordion-like and hourglass-like dispersion relations. These Weyl points are stable against weak perturbations and are protected by the screw rotation symmetry. Based on first-principles calculations we found a complete agreement between the topological predicted energy dispersion relations and real hexagonal materials. Topological charge (chirality) and Berry curvature calculations show the simultaneous formation of Weyl points and nodal-lines in 4d transition-metal trifluorides such as AgF3 and AuF3. Furthermore, a large intrinsic spin-Hall conductivity was found due to the combined strong spin-orbit coupling and multiple Weyl-point crossings in the electronic structure. These materials could be used to the spin/charge conversion in more energy-efficient spintronic devices

Phase equilibrium modelling and implications for P-T determinations of medium-temperature UHP eclogites, North Qaidam terrane, China

In contrast to low-T eclogites (garnet growth zoning preserved) or high-T eclogites (garnet diffusionally homogenized at peak conditions), medium-temperature eclogites pose additional challenges to P-T determinations due to the partial preservation of garnet zoning. The Dulan area, in the southeastern part of North Qaidam ultrahigh-pressure terrane, exposes minor eclogites hosted by ortho- and paragneisses. Four fresh, medium-temperature eclogites contain the paragenesis Grt+Omp+Rt+Qz/Coe+Ph +/- Ky +/- Zo. In all samples, garnet X-Mg shows little zoning, suggesting diffusional modification, and precludes the use of pyrope+almandine+grossular isopleth intersections to determine a P-T path. However, in one sample, sharp zoning in grossular content suggests that grossular growth compositions are preserved. Since garnet pyrope+almandine compositions appear to be modified, we instead use the intersections of grossular and garnet volume isopleths to define a prograde P-T path. This approach yields a path from similar to 17 kbar and similar to 410 degrees C to similar to similar to 35 kbar and similar to 625 degrees C with a gradient of similar to 5-9 degrees C/km through the lawsonite stability field. Peak P-T conditions determined from the intersection between Si pfu in phengite and Zr-in-rutile isopleths are similar to 26-33 kbar and similar to 625-700 degrees C for the four eclogites. These conditions are close to the limit of the lawsonite stability field, suggesting that fluid released from lawsonite breakdown may have promoted re-equilibration at these conditions. These peak conditions are also in good agreement (within 3 kbar and 50 degrees C) with garnet-omphacite-phengite (+/- kyanite) thermobarometry in three of the four samples. We regard the phengite-rutile constraints as more reliable, because they are less sensitive to uncertainties associated with ferric iron compared to conventional thermobarometry. Phase equilibrium modelling predicts that the retrograde assemblage of amphibole+zoisite formed at similar to 60 km. Infiltration of external fluids was likely required for the growth of these hydrous minerals. Based on the comparison of P-T estimation methods applied in this study, we propose that the garnet grossular+volume isopleths can recover the prograde P-T path of medium-temperature eclogites, and that the combination of phengite+rutile isopleths represents a more robust approach to constrain peak P-T conditions