Evidence of the spin Seebeck effect in Ni-Zn ferrites polycrystalline slabs

We report on the observation of the spin Seebeck effect in Ni-Zn ferrites slabs with different Zn concentration. All samples have a spinel structure confirmed by XRD and TEM. We fully characterize the magnetic properties by VSM and Mössbauer spectroscopy. Samples exhibit a nonmonotonic magnetization behavior depending on the structural inversion parameter, however we found a spin Seebeck response voltage of about 25.5 nV/K independent of the magnetization and the inversion degree

Invasive Allele Spread under Preemptive Competition

We study a discrete spatial model for invasive allele spread in which two alleles compete preemptively, initially only the "residents" (weaker competitors) being present. We find that the spread of the advantageous mutation is well described by homogeneous nucleation; in particular, in large systems the time-dependent global density of the resident allele is well approximated by Avrami's law.Comment: Computer Simulation Studies in Condensed Matter Physics XVIII, edited by D.P. Landau, S.P. Lewis, and H.-B. Schuttler, (Springer, Heidelberg, Berlin, in press

Predicting Recurrence and Progression in Patients with Non-Muscle-Invasive Bladder Cancer : Systematic Review on the Performance of Risk Stratification Models

BACKGROUND: Several classifications have been reported to stratify non-muscle-invasive bladder cancer (NMIBC) in risk groups according to the probability of recurrence and progression. OBJECTIVE: To systematically review the current evidence regarding risk stratification of NMIBC. METHODS: The systematic review was performed in accordance with the PRISMA statement. Studies providing data on development and/or external validation cohorts of models and risk stratification tables for recurrence and/or progression for patients with NMIBC, reporting at least one discrimination measure (AUC or C-Index) were included. RESULTS: Twenty-five studies involving 22,737 patients were included. Six classifications were identified, three of them were predictive models (EORTC, CUETO, EAU 2021) and three were based on expert opinion (EAU 2020, AUA, NCCN). A high risk of bias was present in the majority of the studies. Certain heterogenicity was found among the studies regarding adjuvant therapy, postoperative instillation or second resection. The definition of oncological outcomes was not standardized in the included studies. CUETO and EORTC scoring systems are the most validated. In general, validations showed a poor discrimination capability to predict recurrence, slightly better for progression. The EAU 2021 model overestimates the risk of progression in patients treated with BCG. Carcinoma in situ is underrepresented in all the studies analyzed. CONCLUSIONS: The existing classifications show poor discrimination capability for recurrence and possibly helpful discrimination capability for progression in NMIBC patients. These results highlight the unmet need to develop novel accurate risk models for patients with NMIBC, which could be improved with the combination of clinicopathological and molecular information

La práctica evaluativa de los aprendizajes en el área de Comunicación del nivel secundario desde las percepciones de sus principales actores

La práctica evaluativa es entendida como parte del quehacer cotidiano que realiza el docente en su aula, y que favorece en gran medida el aprendizaje de sus estudiantes. Asimismo, es una actividad sobre la que los docentes requieren tener claridad en ciertos aspectos teóricos que brinden el soporte necesario para su realización. Esta investigación da respuesta al siguiente problema de investigación ¿Cómo se realiza la práctica evaluativa de los aprendizajes en el área de Comunicación del VII ciclo del nivel secundario desde las percepciones de docentes y estudiantes en una Institución educativa pública de Lima? La investigación es cualitativa, nivel descriptivo y emplea el método el estudio de casos. Para el recojo de información se aplica dos técnicas. La entrevista a 3 docentes del área de Comunicación y el focus group a 30 estudiantes del VII ciclo del nivel secundario, a fin de conocer las percepciones de estos sobre la práctica evaluativa de los aprendizajes en el área de Comunicación. Entre los principales hallazgos se destaca el hecho que los docentes y estudiantes manifiestan que la práctica evaluativa tiene un fuerte carácter formativo, porque se procura que los estudiantes estén conscientes de su aprendizaje brindándoles los elementos necesarios para ello. Además, se propicia la participación de los estudiantes en la evaluación, a través de la auto y coevaluación; se destaca el empleo de instrumentos de corte cualitativo como las rúbricas y listas de cotejo, que ayudan a la visualización con mayor claridad de los aspectos a mejorar.Tesi

Control selectivo de Maciega (Paspalum virgatum L.) en potreros con MSMA.

Estudio de campo en la Estación Experimental El Nus, Antioquia ICA, con el fín de averiguar las posibilidades de control de Maciega (Paspalum virgatum L.) con ácido monosodio metanoarsonato (MSMA) y otros arsenicales orgánicos en potreros. La cobertura del suelo por Maciega fué reducida de 95 a 30 por ciento o menos con dos o tres aplicaciones de 2 kg/ha de MSMA a intervalos de 12 días. Más del 75 por ciento de la cobertura presente en estos tratamientos, se debió a restablecimiento de la maleza por semilla, pues la Maciega se recupera rápidamente en los tratamientos con una sola aplicación. La adición de surfactante al MSMA no aumentó el control de Maciega, ni éste fué el mejor cuando se aplicó el herbicida sobre rebrotes suculentos. Los pastos deseables, janeiro (Eriochloa polystachya) y pará (Brachiaria mutica) fueron tolerantes a 8 P kg/ha de MSMA aplicados de una vez. Los pastos guinea (Panicum maximum) y puntero (Hyparrhemia rufa) fueron temporalmente afectados por el mismo tratamiento. Los resultados indican que el MSMA y otros arsenicales orgánicos pueden ser utilizados en el control selectivo de Maciega en potreros y algunos pastos tropicales

Relativistic Ring-Diagram Nuclear Matter Calculations

A relativistic extension of the particle-particle hole-hole ring-diagram many-body formalism is developed by using the Dirac equation for single-particle motion in the medium. Applying this new formalism, calculations are performed for nuclear matter. The results show that the saturation density is improved and the equation of state becomes softer as compared to corresponding Dirac-Brueckner-Hartree-Fock calculations. Using the Bonn A potential, nuclear matter is predicted to saturate at an energy per nucleon of --15.30 MeV and a density equivalent to a Fermi momentum of 1.38 fm$^{-1}$, in excellent agreement with empirical information. The compression modulus is 152 MeV at the saturation point.Comment: 23 pages text (LaTex) and 2 figures (paper, will be faxed upon request), UI-NTH-92-0

Silicon-on-insulator polarization controller with relaxed fabrication tolerances

Polarization control is essential in applications ranging from optical communications to interferometric sensors. The implementation of in- tegrated polarization controllers is challenging as they require polariza- tion rotating waveguides with stringent fabrication tolerances. Here, we present a fully integrated polarization controller scheme that signi cantly relaxes the requirements on the rotating waveguides, alleviating fabri- cation tolerances. We analytically establish a technology-independent, easily measurable tolerance condition for the rotating waveguides. Po- larization control in the presence of waveguide width errors of 25% is shown through full vectorial simulation.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

Fine-Tuning Solution for Hybrid Inflation in Dissipative Chaotic Dynamics

We study the presence of chaotic behavior in phase space in the pre-inflationary stage of hybrid inflation models. This is closely related to the problem of initial conditions associated to these inflationary type of models. We then show how an expected dissipative dynamics of fields just before the onset of inflation can solve or ease considerably the problem of initial conditions, driving naturally the system towards inflation. The chaotic behavior of the corresponding dynamical system is studied by the computation of the fractal dimension of the boundary, in phase space, separating inflationary from non-inflationary trajectories. The fractal dimension for this boundary is determined as a function of the dissipation coefficients appearing in the effective equations of motion for the fields.Comment: 10 pages, 4 eps figures (uses epsf), Revtex. Replaced with version to match one in press Physical Review

The valence-fluctuating ground state of plutonium

A central issue in material science is to obtain understanding of the electronic correlations that control complex materials. Such electronic correlations frequently arise because of the competition of localized and itinerant electronic degrees of freedom. Although the respective limits of well-localized or entirely itinerant ground states are well understood, the intermediate regime that controls the functional properties of complex materials continues to challenge theoretical understanding. We have used neutron spectroscopy to investigate plutonium, which is a prototypical material at the brink between bonding and nonbonding configurations. Our study reveals that the ground state of plutonium is governed by valence fluctuations, that is, a quantum mechanical superposition of localized and itinerant electronic configurations as recently predicted by dynamical mean field theory. Our results not only resolve the long-standing controversy between experiment and theory on plutonium’s magnetism but also suggest an improved understanding of the effects of such electronic dichotomy in complex materials.JRC.E.6-Actinide researc