Ab-initio analysis of superstructures revealed by STM on bilayer graphene

In this work we performed density functional theory calculations for a twisted bilayer graphene (BLG). Several conmensurable rotation angles were analyzed and for each one a constant height mode STM image was obtained. These STM images, calculated under the Tersoff-Hamman theory, reproduce the main features experimentally observed, paticularly superstructures and giant corrugations. In this way we confirm that STM characterization of twisted BLG can produce superstructures whose tunneling current intensity maxima occur over regions with $AA$ stacking. Additionally we give new evidence in favour of an electronic origin for the superstructures instead another physical grounds

Moir\'e patterns on STM images of graphite from surface and subsurface rotated layer

We have observed with STM moir\'e patterns corresponding to the rotation of one graphene layer on HOPG surface. The moir\'e patterns were characterized by rotation angle and extension in the plane. Additionally, by identifying border domains and defects we can discriminate between moir\'e patterns due to rotation on the surface or subsurface layer. For a better understanding of moir\'e patterns formation we have studied by first principles an array of three graphene layers where the top or the middle layer appears rotated around the stacking axis. We compare the experimental and theoretical results and we show the strong influence of rotations both in surface and subsurface layers for moir\'e patterns formation in corresponding STM images.Comment: 5 pages, 6 figure

DIAGNÓSTICO NUTRICIONAL DE NIÑOS ENTRE 3 Y 5 AÑOS QUE ASISTEN AL JARDÍN INFANTIL “LA GOTITA” DE PUERTO MONTT, DURANTE EL PRIMER SEMESTRE DEL AÑO 2006. VALDIVIA. CHILE

Infantile obesity is an important problem of public health whose prevention measures should start in the early stages of life, where parents should be involved. If parents are not able to detect overweight or obesity in their own children, measures carried out to prevent the infantile obesity will be hardly successful. Te aim of the present quantitative, cross-section, and descriptive investigation, not experimental, was to determine the nutritional state of children that attend the Kindergarten La Gotita, in Puerto Montt, during the first semester of 2006, regarding age, gender, weight and size. The studied population, after having applied exclusion criteria, was constituted by 107 children, of which 56% were men and the remaining 44% were women. According to nutritional state, by age, children in risk of undernourished were 8% and it decreased to 0% at the age of 5. Within this group of children in risk of undernourished, none of them presented size deficit. Additionally, the children with overweight dropped from 14% in March to 9% in July, obese children also dropped from 10% in March to 9% in July. Overweight was observed in all ages in both genders and a deficit in children of 3 and 4 years old in both genders. The proportion of obese women was higher than in men in every month of the study and at all ages. Less than half (20%) of obese children’s parents did not presented chronic illnesses no-communicable, risk factors, considered inside the norm of outpatient handling with overweight due to undernourishment. Therefore, it is extremely important while evaluating an obese child. The children of this study, at all ages and in both genders have high percentages of overweight and obesity. Less than half (7.4%) that is managed at national level, thus it becomes necessary to adopt preventive measures from an early age such as, motivating mothers to maintain their children controlling their health constantly during the previous preschool years, developing specific educational programs about appropriate feeding for each age, promoting healthy habits, and avoiding little physical activity, since those factors may lead to complications in the adulthood.La obesidad infantil es un problema importante de salud pública cuyas medidas de prevención deben iniciarse en etapas tempranas de la vida, en las que deben involucrarse los padres. Si éstos no son capaces de percibir el sobrepeso o la obesidad en sus hijos preescolares, difícilmente las medidas destinadas a prevenir la obesidad infantil podrán tener éxito. La presente investigación cuantitativa, transversal, descriptiva, no experimental, buscó determinar el estado nutricional de los niños que asisten al Jardín Infantil La Gotita, de Puerto Montt, durante el primer semestre del año 2006, en relación a la edad, sexo, peso y talla. La población en estudio, luego de aplicar criterios de exclusión, quedó conformada por 107 niños, de los cuales el 56% corresponde a hombres y el restante 44% a mujeres. Según estado nutricional, por año de edad, los niños en riesgo de desnutrir son el 8% y disminuyen a 0% a los 5 años. De este grupo de niños con riesgo de desnutrir, ninguno presentaba déficit de talla. Los niños con sobrepeso disminuyen de 14% en marzo, a un 9% en julio; los niños obesos también disminuyen de 10% en marzo, a 9% en julio. Se observa exceso de peso en todas las edades en ambos sexos. Y déficit en niños de 3 a 4 años, también en ambos sexos. La proporción de mujeres con obesidad es mayor que la de los hombres, en todos los meses del estudio y en todas las edades. El 20% de los padres de niños obesos, presentó enfermedades crónicas no transmisibles, factores de riesgo considerados dentro de la norma para el “manejo ambulatorio de la malnutrición por exceso” del ministerio y, por lo tanto, muy importante en el momento de evaluar a un niño obeso. Por lo que se refiere a los niños de este estudio, en todas las edades y en ambos sexos encontramos alta prevalencia de sobrepeso y obesidad, por sobre el 7.4% que se maneja a nivel nacional, lo que amerita adoptar medidas preventivas desde temprana edad: incentivar a las madres a mantener a sus hijos en control de salud constante durante la etapa preescolar; desarrollar programas educativos específicos sobre alimentación adecuada para cada edad; fomentar hábitos saludables y evitar el sedentarismo, ya que ellos, son factores conducentes a complicaciones en la edad adulta

Stability of Bar Code Information Stored in Magnetic Nanowire Arrays

Firmware applications such as security codes, magnetic keys, and similar products can be stored in magnetic bar codes similar to optical bar codes. This can be achieved on the triangular lattice present in porous alumina, whose pori can be filled by magnetic material, over which magnetic bar codes can be inscribed. We study the conditions to improve the durability of the stored information by minimizing the repulsive energy among wires with parallel magnetization within the same bar but interacting with attractive energy with wires in the neighboring bar. The following parameters are varied to minimize the energy of the system: relative amount of magnetization orientation within the bar code area in any orientation, width of the bars, and distribution of wider bars to the outside or to the inside of the code. It is found that durability of the code is favored for equal amount of magnetization in each direction, abundance of narrow bars trying to locate a few wider ones towards the center. Three real commercial optical bar codes taken at random were mapped into magnetic bar codes; it is found that the corresponding magnetic energies are similar to those analyzed here which provides a realistic test for this approach

H-alpha kinematics of S4G spiral galaxies-II. Data description and non-circular motions

We present a kinematical study of 29 spiral galaxies included in the Spitzer Survey of Stellar Structure in Galaxies, using Halpha Fabry-Perot data obtained with the Galaxy Halpha Fabry-Perot System instrument at the William Herschel Telescope in La Palma, complemented with images in the R-band and in Halpha. The primary goal is to study the evolution and properties of the main structural components of galaxies through the kinematical analysis of the FP data, complemented with studies of morphology, star formation and mass distribution. In this paper we describe how the FP data have been obtained, processed and analysed. We present the resulting moment maps, rotation curves, velocity model maps and residual maps. Images are available in FITS format through the NASA/IPAC Extragalactic Database and the Centre de Donn\'ees Stellaires. With these data products we study the non-circular motions, in particular those found along the bars and spiral arms. The data indicate that the amplitude of the non-circular motions created by the bar does not correlate with the bar strength indicators. The amplitude of those non-circular motions in the spiral arms does not correlate with either arm class or star formation rate along the spiral arms. This implies that the presence and the magnitude of the streaming motions in the arms is a local phenomenon.Comment: 23 pages, 14 figures, without appendices, accepted to be published in MNRA

Soil Water Movement in a Watershed in the Chilean Patagonia

Magallanes region, located southern Chile, contains about 1.9 million sheep heads, in about 5 million hectares of rangelands. However, forage production is concentrated in small wetlands meadows called locally “Vegas” that only represent about 300.000 hectares. Those ecosystems that sustain patagonian ranches, produce 20 times more forage biomass than the surrounding natural rangelands. Patagonian vegas have concave topography with a hydrophyte (wet) center, and mesic slopes and xeric highlands of Festuca gracillima. Although the moisture content is controled by topography, there is scarce information about the movement of water through this concave topography. Also, the spatial variability of the soil between the Xeric to the Hydrophyte parts must be taking in account. It is essential to evaluate the movement of water inside the soil, to define agronomic managements to promote the storage and conduction of water. The study was conducted in a watershed dominated by vegas at the Kampenaike Experimental Station in Magallanes region, in Chilean Patagonia (-52,7 ° Lat.; -70.97° Long). Soil was monitored by instruments in five pits, two at East and West of Xeric side; two at East and West of mesic side; and the last at the middle of the vega. Soil moisture sensors (n = 2) and water tension (n = 1) were placed in three soil horizons (5, 30 and 80 cm deep). A weather station was set up in the middle of the vega. Differences in the physical properties that govern the storage and conduction of water between all the sectors were founded. The differences were due to the great spatial variability of the type of soil, because the topography and the genesis