Structural properties in Sr0.61a0.39Nb2O6 in the temperature range 10 K to 500 K investigated by high-resolution neutron powder diffraction and specific heat measurements

We report high-resolution neutron powder diffraction on Sr0.61Ba0.39Nb2O6, SBN61, in the temperature range 15-500 K. The results indicate that the low-temperature anomalies (T<100K) observed in the dielectric dispersion are due to small changes in the incommensurate modulation of the NbO6-octahedra, as no structural phase transition of the average structure was observed. This interpretation is supported by specific heat measurements, which show no latent heat, but a glass-like behavior at low temperatures. Furthermore we find that the structural changes connected with the ferroelectric phase transition at Tc approx. 350K start already at 200K, explaining the anisotropic thermal expansion in the temperature range 200-300K observed in a recent x-ray diffraction study.Comment: Accepted by PRB (2006

Neutron scattering study of the field-dependent ground state and the spin dynamics in S=1/2 NH4CuCl3

Elastic and inelastic neutron scattering experiments have been performed on the dimer spin system NH4CuCl3, which shows plateaus in the magnetization curve at m=1/4 and m=3/4 of the saturation value. Two structural phase transitions at T1≈156  K and at T2=70  K lead to a doubling of the crystallographic unit cell along the b direction and as a consequence a segregation into different dimer subsystems. Long-range magnetic ordering is reported below TN=1.3  K. The magnetic field dependence of the excitation spectrum identifies successive quantum phase transitions of the dimer subsystems as the driving mechanism for the unconventional magnetization process in agreement with a recent theoretical model

M\"ossbauer, nuclear inelastic scattering and density functional studies on the second metastable state of Na2[Fe(CN)5NO]⋅\cdot2H2O

The structure of the light-induced metastable state SII of Na2[Fe(CN)5NO]$\cdot$2H2O 14 was investigated by transmission M\"ossbauer spectroscopy (TMS) in the temperature range 15 between 85 and 135 K, nuclear inelastic scattering (NIS) at 98 K using synchrotron 16 radiation and density functional theory (DFT) calculations. The DFT and TMS results 17 strongly support the view that the NO group in SII takes a side-on molecular orientation 18 and, further, is dynamically displaced from one eclipsed, via a staggered, to a second 19 eclipsed orientation. The population conditions for generating SII are optimal for 20 measurements by TMS, yet they are modest for accumulating NIS spectra. Optimization 21 of population conditions for NIS measurements is discussed and new NIS experiments on 22 SII are proposed

Classical generalized constant coupling model for geometrically frustrated antiferromagnets

A generalized constant coupling approximation for classical geometrically frustrated antiferromagnets is presented. Starting from a frustrated unit we introduce the interactions with the surrounding units in terms of an internal effective field which is fixed by a self consistency condition. Results for the magnetic susceptibility and specific heat are compared with Monte Carlo data for the classical Heisenberg model for the pyrochlore and kagome lattices. The predictions for the susceptibility are found to be essentially exact, and the corresponding predictions for the specific heat are found to be in very good agreement with the Monte Carlo results.Comment: 4 pages, 3 figures, 2 columns. Discussion about the zero T value of the pyrochlore specific heat correcte

Effect of noise on coupled chaotic systems

Effect of noise in inducing order on various chaotically evolving systems is reviewed, with special emphasis on systems consisting of coupled chaotic elements. In many situations it is observed that the uncoupled elements when driven by identical noise, show synchronization phenomena where chaotic trajectories exponentially converge towards a single noisy trajectory, independent of the initial conditions. In a random neural network, with infinite range coupling, chaos is suppressed due to noise and the system evolves towards a fixed point. Spatiotemporal stochastic resonance phenomenon has been observed in a square array of coupled threshold devices where a temporal characteristic of the system resonates at a given noise strength. In a chaotically evolving coupled map lattice with logistic map as local dynamics and driven by identical noise at each site, we report that the number of structures (a structure is a group of neighbouring lattice sites for whom values of the variable follow certain predefined pattern) follow a power-law decay with the length of the structure. An interesting phenomenon, which we call stochastic coherence, is also reported in which the abundance and lifetimes of these structures show characteristic peaks at some intermediate noise strength.Comment: 21 page LaTeX file for text, 5 Postscript files for figure

Promoción de la huerta orgánica y de alimentación saludable en niños de la EEP Nº7 de Puerto Tirol, Chaco

El modelo educativo que tienen actualmente los niños de nuestra región nordeste no desarrolla su capacidad para elegir alimentos saludables, así van adquiriendo hábitos de alimentación no saludables que mantendrán durante toda su vida, a menos que se realice una intervención integral efectiva. La Organización de las Naciones Unidas para la Alimentación y la Agricultura (FAO) considera que los huertos escolares pueden ayudar a mejorar la nutrición y la educación de los niños y familiares, tanto en zonas rurales como urbanas, por lo que alienta a las Escuelas a crear huertos de aprendizaje que puedan ser manejados por los mismos escolares, profesores y padres, que incluyan una variedad de hortalizas y frutas. Se trabajó en una Escuela Primaria de la localidad de Puerto Tirol, Chaco, a la que asisten 575 alumnos con edades de 6 a 14 años, distribuidos en turnos mañana y tarde. Los Objetivos fueron: a) Detectar niños con alteraciones nutricionales y/o hábitos de alimentación saludables, b) Promover hábitos saludables de alimentación, y c) Promover prácticas agroecológicas al reinstalar la huerta orgánica escolar. Materiales y métodos: Se evaluó el estado nutricional y hábitos alimentarios de los alumnos a través de encuestas alimentarias, datos antropométricos y de laboratorio. Se usó la huerta como aula práctica para aprender sobre agroecología, nutrición, disfrute y esparcimiento.Se realizó asistencia técnica, acompañamiento y provisión de insumos para la producción de la huerta. Se realizaron talleres informativos con tutores y docentes, y actividades lúdicas con alumnos de ambos turnos. Resultados: Se encuestó a 258 niños (45% del total): al 99% le gustaban las frutas y al 88% las verduras, pero consumían con frecuencia un 53% frutas y un 59% verduras en sus hogares. Compraban en el kiosco escolar alimentos ricos en azúcar, sal y grasas trans. Los niños expresaron su interés en disponer de frutas y licuados en el kiosco. Respecto a los datos antropométricos sobre 150 niños, un 20 % presentaba bajo peso para su talla y un 10 % sobrepeso.Sobre los análisis de laboratorio realizados a 39 alumnos: un 15% presentaba anemia, un7,7% creatininemias bajas y ninguno elevada. La albúmina resultó normal en todos. Se reinstaló la huerta escolar con participación de alumnos de 5° a 7° grado. Las hortalizascosechadas fueron consumidas por la Escuela y por los alumnos en sus hogares.

Reviews of

Antibiotic Switch therapy is defined by the switch of intravenous antibiotic therapy to oral form. This research aimed to learn about the relationship of switch therapy toward the value of wound healing, lenght of stay and the antibiotic expenditure. The data of this cross sectional study was collected from medical record and by direct investigation to patients for their macroscopis the wound healings value. T-test was used to compared the relationship of the patient wound healings value, lenght of stay and the antibiotic expenditure between the those with and accurate switch therapy and those without it. The result showed that there was no different of wound healing value between those groups of patients (P>0,1). On the other hand, lenght of stay and antibiotic expenditure of the patient with the accurate switch therapy was cuted on the patient with the accurate switch therapy. These indicated that accuracy of switch therapy will proceed a benefit outcome to the patient with appendicitis, especially to there lenght of stay and antibiotic expenditure as well