Linear magnetoresistivity in layered semimetallic CaAl2Si2.

According to an earlier Abrikosov model, a positive, nonsaturating, linear magnetoresistivity (LMR) is expected in clean, low-carrier-density metals when measured at very low temperatures and under very high magnetic fields. Recently, a vast class of materials were shown to exhibit extraordinary high LMR but at conditions that deviate sharply from the above-mentioned Abrikosov-type conditions. Such deviations are often considered within either classical Parish-Littlewood scenario of random-conductivity network or within a quantum scenario of small-effective mass or low carriers at tiny pockets neighboring the Fermi surface. This work reports on a manifestation of novel example of a robust, but moderate, LMR up to ∼100 K in the diamagnetic, layered, compensated, semimetallic CaAl2Si2. We carried out extensive and systematic characterization of baric and thermal evolution of LMR together with first-principles electronic structure calculations based on density functional theory. Our analyses revealed strong correlations among the main parameters of LMR and, in addition, a presence of various transition/crossover events based on which a P - T phase diagram was constructed. We discuss whether CaAl2Si2 can be classified as a quantum Abrikosov or classical Parish-Littlewood LMR system.

Enteroparasitosis y estado nutricional en niños menores de 4 años de wawa-wasi de Pamplona Alta San Juan de Miraflores Lima - Perú - 2006 / Enteroparasities and nutritional status in children younger than 4 years old from daycare centers of pamplona Alta San Juan de Miraflores, Lima, Peru, 2006

Se realizó un estudio prospectivo transversal de 112 niños entre 1 a 4 años de tres wawa wasi del área de Pamplona Alta en el distrito de San Juan de Miraflores con la finalidad de estudiar la prevalencia de enteroparasitosis y su relación con el estado nutricional. Para determinar la prevalencia de parasitosis intestinal se utilizó la Técnica de Burrows (PAF), para el diagnóstico de Enterobius vermicularis se utilizaron el método de la cinta engomada o Test de Grahan. Para determinar el estado nutricional se clasificó a los participantes en 4 categorías según el indice de Waterlow: eutrófico, desnutrido agudo, desnutrido crónico compensado y desnutrido crónico reagudizado, se emplearon los indicadores Antropométricos: peso/edad, talla/edad, peso/talla, para lo cual se utilizaron tablas antropométricas de la National Center for Health Stadistics del 2004. En cuanto a la prevalencia de parasitosis fueron positivas en el 82 por ciento de la población 18 por ciento de las muestras resultaron negativas. Se encontró que Enterobirus vermicularis fue el parásito más frecuente con 66 por ciento de los casos, seguido por Giardia Lamblia 17 por ciento. Se encontró que el 55 por ciento de la población fueron eutróficos, 7 por ciento desnutridos agudos y 38 por ciento desnutridos crónicos compensados. De los niños eutróficos el 73 por ciento estaban parasitados, mientras que el 91 por ciento de los 100 por ciento de los desnutridos agudos tenían parásitos. Con estos resultados nutricional y la frecuencia de enteroparasitosis en la población estudiada.

Prospective study of 112 children cross between 1 and 4 years of three wawa wasi Pamplona Alta area in the district of San Juan de Miraflores with the aim of studying the prevalence of enteroparasitosis and its relationship with the state nutritional. To determine the prevalence of intestinal parasitosis used the technique Burrows (PAF) for the diagnosis of Enterobius vermicularis is the method used tape or rubberized test Graham. To determine the nutritional status was classified the participants into 4 categories according to the index Waterlow: eutrófico, acute undernourished, underfed and malnourished chronic harmonious chronic reagudización, were used anthropometric indicators: weight/age, height/age, weight / height for which were used anthropometric tables of the National Center for Health Stadistics 2004. As for the prevalence of parasites were positive for 82 per cent of the population 18 per cent of samples were negative. It was that Enterobirus vermicularis was the most frequent parasitie with 66 per cent of cases, followed by Giardia lamblia 17 per cent. It was found that 55 per cent of the population were eutrophic, 7 per cent acute malnutrition amd 38 per cent chronically malnourished compensated. Of the children eutróficos 73 per cent were infected, while 91 per cent of chronically malnourished offset were infested, and 100 per cent of acute had parasities. We conclude that there is a strong link between nutritional status and frequency of enteroparasitosis in the population studied.

Detección precoz de enfermedad renal en escolares asintománticos de 5-12 años en el centro Educativo 6097 "Mateo Pumacahua" en Surco - Lima * Setiembre - Octubre 2007 / Early detection of renal disease in school children 5-12 years of asintománticos at school 6097

El nuevo enfoque para el tratamiento de pacientes pediátricos renales se orienta a la detección temprana de la enfermedad renal. El objetivo fue identificar la presencia de patología urinaria precoz en pacientes sin síntomas renales y determinar su factibilidad para prevenir el desarrollo de insuficiencia renal crónica terminal, en escolares asintomáticos de 5-12 años del CE. 6097 "Mateo Pumacahua" en el distrito de Surco en Lima. Se realizó un exámen de orina mediante tiras reactivas. A los resultados positivos para leucocituria se les tomó una muestra adicional el mismo día para realizar un sedimento y urocultivos. Las muestras positivas para hematuria y proteinuria fueron incluidos en una segunda toma de muestras dos semanas después. De persistir éstas, se procedió a realizar un sedimento urinario. Durante la primera toma de muestra se encontraron: Hematíes positivos (2,84%), nitritos positivos (1,54%), proteinas positivas (1,03%) y leucocitos positivos (0,77%). Se encontró que el 75% de las hematurias y el 100% de las proteinurias y leucociturias correspondían a pacientes de sexo femenino. Además se halló una mayor incidencia de resultados patológicos en el grupo etáreo de 9-12 años que en el de 5-8 años. Los porcentajes de leucocituria, hematuria y proteinuria (5,41%) fueron menores que en la bibliografía consultada. Un mayor (4,12%) al reportado por anteriores investigaciones, persistió con una muestra patológica al realizar una nueva toma de muestras y sedimento. Es recomendable realizar campañas preventivas de detección de patología renal precoz ya que se enncuentran un alto porcentaje de niños con resultados persistentes patológicos.

The new approach for treating pediatric kidney patients is aimed at early detection of kidney disease. Our goal was to identify the presence of patology early urinary symptoms in patients without kidney and determine their feasibility to prevent the development of chronic renal failure terminal, asymptomatic school children 5-12 years of Estatal Center. 6097 "Matthew Pumacahua" of Surco district. A review was conduted using urine test strips. The positive result for leucocituria they took and additional sample the same day for a urine culture and sediment. Positive samples for hematuria and proteinuria were included in a second sampling two weeks later. Of these persist, it proceeded to conduct a urine sediment. During the first sampling were found: red cells positive (2.84%) and nitrates positive (1.54%), proteins positive (1.03%) and positive leukocytes (0.77%) was found that 75% from hematuria and 100% of proteinuria and leucocituria corresponded to female patients. Also found was a higter incidence o pathological findieng in the age group 9-12 years than in the rates of 5-8 years. The percents of leucocituria, hematuria and proteinuria (5.41%) were lower than in the literature. A higher percentage (4.12%) reported by previous investigations, pathological persisted with a sample to make a new sampling and sediment. We recommend preventive campaigs to detect early kidney disease because there is a high percentage of children with persistent pathological results.

Twisted plywood pattern of collagen fibrils in teleost scales: an X-ray diffraction investigation.

The distribution and orientation of collagen fibrils, and apatite crystals, in the scales of a bony fish (Leuciscus cephalus) were investigated by X-ray diffraction. The small-angle diffraction patterns obtained with a microfocus scanning setup from most of the examined areas exhibit a distribution of intensity of the collagen reflections according to five preferential orientations, at 36 degrees from one another. It is suggested that the peculiar small-angle X-ray diffraction pattern is due to a plywood arrangement of collagen fibrils in successive layers parallel to the surface of the scale. The fibrils are strictly aligned in each layer and the alignment rotates by 36 degrees in successive layers, according to a discontinuous twist that generates a symmetric plywood pattern. The large spread of the wide-angle reflections does not allow one to distinguish the five directions of orientation in the intensity distribution of the 002 reflection of apatite. However, the patterns recorded from the less ordered regions of the scales display two different orientations of the 002 reflection and allow one to infer a preferential distribution of the apatite crystals with their c-axes parallel to the collagen fibrils. Although much electron microscopic evidence of plywood arrangements in calcified, as well as uncalcified, tissues has been reported, these are the very first diffraction data which unambiguously confirm the presence of these peculiar structures and suggest that this kind of investigation represents a powerful tool with which to study plywood arrangements in biological tissues.