Damages caused by cotton rat, Sigmodon hispidus zanjonensis, on sugar cane in San Pedrosula, Honduras

Technical assistance was given to Compañía Azucarera Hondureña, S.A. (Agro-Industrial Co.), Honduras, Central America, to determine if a campaign against noxious rodents to agriculture crops was needed. Several trappings were carried out at different places using snap traps to determine the population structure of rodents associated with the crop, and live traps to determine the index or density of the Sigmodon hispidus rat population, which was identified as being responsible for the damage to sugarcane. Results were 43.24% adult males, 14.86% young males, 31.41% adult females, and 10.47% young females. Of the adult females captured, 54.83% were pregnant with an average of 3 to 4 embryos per rat. A control demonstration combat was carried out at one of the experimental stations with a bait prepared with 2% zinc phosphide in a place where it had been previously determined there was a population of 39 rats per hectare. After such control, the population was reduced to 18 rats per hectare, which represents an efficiency of 53.85%. An evaluation of damages was also measured at different places to determine the degree of loss caused by the rats, which proved to be 22.79% damage. The size of the sample was estimated in 3 samples per hectare, with a level of confidence of 95%

Scintillation observations at Ancon and Jicamarca Observatories

Satellite scintillation and diffraction pattern scale size distribution from ionospheric irregularitie

Enhancement of photoacoustic detection of inhomogeneities in polymers

We report a series of experiments on laser pulsed photoacoustic excitationin turbid polymer samples addressed to evaluate the sound speed in the samples and the presence of inhomogeneities in the bulk. We describe a system which allows the direct measurement of the speed of the detected waves by engraving the surface of the piece under study with a fiduciary pattern of black lines. We also describe how this pattern helps to enhance the sensitivity for the detection of an inhomogeneity in the bulk. These two facts are useful for studies in soft matter systems including, perhaps, biological samples. We have performed an experimental analysis on Grilon(R) samples in different situations and we show the limitations of the method.Comment: 8 pages, 7 figure

Fiber optic mechanical vibration sensor

A novel cantilever-type fiber Bragg grating (FBG) mechanical vibration sensor has been proposed with an excellent sensitivity through the use of the mechanical axial property of a suspended optical fiber with two fixed ends, enhancing the sensitivity and the resonant frequency. The experimental results show a resolution of 0.006g (where g represents the gravitational acceleration of 1g= 9.81 m/s2), a resonant frequency of 227.3 Hz and a working bandwidth range of 10-210 Hz. The linearity and relative sensitivity errors are 1.9 % and ±4.4 %, respectively

Density-Matrix functional theory of strongly-correlated lattice fermions

A density functional theory (DFT) of lattice fermion models is presented, which uses the single-particle density matrix gamma_{ij} as basic variable. A simple, explicit approximation to the interaction-energy functional W[gamma] of the Hubbard model is derived from exact dimer results, scaling properties of W[gamma] and known limits. Systematic tests on the one-dimensional chain show a remarkable agreement with theBethe-Ansatz exact solution for all interaction regimes and band fillings. New results are obtained for the ground-state energyand charge-excitation gap in two dimensions. A successful description of strong electron correlations within DFT is achieved.Comment: 15 pages, 6 figures Submitted to PR

Enfrentamiento terapéutico del trastorno por déficit atencional en una población infantil escolar perteneciente a la Región Metropolitana de Chile

Indexación: ScieloAn evaluation was made of a retrospective evolution presented by the patients from to 14 years and 11 month old (average 9,2 years old), with a diagnostic of attentional hyperactive disorder (AHD), treated with metilfenidate in Huechuraba during the year 2007. A revision of every clinic history showed the principal results: a high positive response (higher than the 76% of the measured parameters). The evaluated parameters were, academic response, self report of subjective opinion from the patient, opinion from the tutor of the child in relationships with his/her conduct at home and teacher's evaluations of the child conduct at school. No differences were found between the evolution of the clinic parameters, in children with and without comorbilities. It was found a 52, 7% of comorbility. Specific learning disease, adaptative disorder, anxious disorder, and depression were more frequent diagnoses. This study concludes that the high percent of success in the treatment of the student group is similar to the one found in literature. The presence of comorbility won't cause to down of the treatment efficiency. This is conditioned by the presence of psychosocial factors like maternal psychopathology and familiar violence.Se realizó una evaluación restrospectiva de la evolución presentada por los pacientes desde 6 a 14 años 11 meses de edad (edad media de 9,2 años) con diagnóstico de Trastorno por déficit atencional (TDA) bajo tratamiento con metilfenidato en la comuna de Huechuraba durante el año 2007. Se hizo la revisión y el análisis de cada ficha clínica, encontrándose como principales resultados el alto porcentaje de mejoría, igual o mayor al 76% de los parámetros medidos, consistentes en evolución del rendimiento académico; autoreporte de sensación subjetiva del niño; reporte del cuidador principal en relación a la conducta del niño (a) en el hogar y evaluación del profesor en cuanto su conducta en el colegio. No se encontraron diferencias entre la evolución de los parámetros clínicos entre los niños con comorbilidad y sin comorbilidad, se encontró un 52,7% de esta, siendo los diagnósticos más frecuentes Trastorno específico del aprendizaje, trastorno adaptativo, trastorno ansioso y del ánimo. Se concluye que el alto porcentaje de éxito del tratamiento en el grupo estudiado es similar al encontrado en la literatura; que la presencia de comorbilidad no condiciona la disminución de la eficiencia del tratamiento y que esta es condicionada por presencia de factores psicosociales como psicopatología materna y violencia intrafamiliar.http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0717-92272009000100005&nrm=is