Global superscaling analysis of quasielastic electron scattering with relativistic effective mass

We present a global analysis of the inclusive quasielastic electron scattering data with a superscaling approach with relativistic effective mass. The SuSAM* model exploits the approximation of factorization of the scaling function $f^*(\psi^*)$ out of the cross section under quasifree conditions. Our approach is based on the relativistic mean field theory of nuclear matter where a relativistic effective mass for the nucleon encodes the dynamics of nucleons moving in presence of scalar and vector potentials. Both the scaling variable $\psi^*$ and the single nucleon cross sections include the effective mass as a parameter to be fitted to the data alongside the Fermi momentum $k_F$. Several methods to extract the scaling function and its uncertainty from the data are proposed and compared. The model predictions for the quasielastic cross section and the theoretical error bands are presented and discussed for nuclei along the periodic table from $A=2$ to $A=238$: $^2$H, $^3$H, $^3$He, $^4$He, $^{12}$C, $^{6}$Li, $^{9}$Be, $^{24}$Mg, $^{59}$Ni, $^{89}$Y, $^{119}$Sn, $^{181}$Ta, $^{186}$W, $^{197}$Au, $^{16}$O, $^{27}$Al, $^{40}$Ca, $^{48}$Ca, $^{56}$Fe, $^{208}$Pb, and $^{238}$U. We find that more than 9000 of the total $\sim 20000$ data fall within the quasielastic theoretical bands. Predictions for $^{48}$Ti and $^{40}$Ar are also provided for the kinematics of interest to neutrino experiments.Comment: 26 pages, 20 figures and 4 table

Semiempirical formula for two-nucleon emission induced by short-range correlations in electron and neutrino scattering

A semiempirical formula is proposed for the emission cross section of two correlated nucleons. We assume that the two-particle emission response is proportional to the two-particle two-hole phase space multiplied by an averaged single-nucleon response. The effect of the short-range correlations is encoded in a correlation coefficient that is linked to an average of the high-momentum distribution of a nucleon pair. The correlation coefficient depends only on the momentum transfer and is obtained from a fit to the tail of the phenomenological scaling function. We present predictions for the inclusive two-nucleon emission cross section induced by electrons and neutrinos including short-range correlations and meson-exchange currents.Comment: 14 pages, 8 figures. Major revision, with 5 more pages, a new section, an appendix and a figur

Properties of aluminium nodules foamed with concentrated solar energy

Commercial aluminium foam filled structures and sandwich panels are available for structural applications. As alternative to these materials, small granular foamed pieces are proposed to fill structures as well as sandwich panels. On the present work, foam precursors are obtained by Powder Metallurgy (PM) route, using natural calcium carbonate as foaming agent instead of titanium hydride. Extruded precursor bars were cut into small pieces (around 4.5 mm long and 5mm in diameter). Foaming treatment was carried out on two different ways: electrical preheated furnace and by solar furnace. Foamed nodules presented a low cell size, density e.g. 0.67 g/cm3 to 0.88 g/cm3 and a height/diameter ratio between 0.72 and 0.84 as a function of precursor size. These properties depend on the foaming particle size, foaming cycle and precursor dimensions. Carbonate precursors are easily foamed by concentrated solar energy, due to the lower risk of cell collapse than with hydride precursors, resulting from cell stabilization by oxide skin formation into cells and a low degree of foamed nodules bonding

Tratamiento térmico de espumación de precursores de aluminio-silicio en horno solar de lecho fluidificado

La fabricación de espumas de aluminio de poro cerrado mediante técnicas pulvimetalúrgias, conlleva una etapa de calentamiento del material (precursor) hasta su fusión y la formación de la espuma. En el presente trabajo, como continuación de los trabajos con energía solar concentrada aplicada directamente a la espumación de precursores Al10Si+0.8%TiH2, se han sometido al tratamiento de espumación en un horno solar de lecho fluidificado con el objetivo de obtener un tratamiento en volumen más homogéneo y uniforme, de manera que se puedan determinar la viabilidad del tratamiento, el procedimiento y los tiempos de residencia necesarios para llevar a cabo este proceso de manera discontinua o preindustrial. Así se han obtenido espumas 0,68 g/cm3 de densidad sin colapso de poros o decantación de aluminio, si bien como consecuencia del calentamiento preferencial por la base del molde, las espumas obtenidas presentan un tamaño de poro ligeramente más grande en la base de la espuma

Consumo de jamón curado e incidencia de eventos cardiovasculares, hipertensión arterial o ganancia de peso

Fundamento y objetivo: El jamón curado es uno de los alimentos característicos de la dieta mediterránea española. Sin embargo, no existe ningún estudio epidemiológico prospectivo que haya valorado sus efectos sobre la salud humana. Nuestro objetivo fue evaluar la asociación entre el consumo de jamón curado y la incidencia de hipertensión arterial, enfermedad cardiovascular y/o ganancia de peso. Sujetos y método: En una cohorte epidemiológica prospectiva y dinámica de 13.293 graduados universitarios (Proyecto SUN) se analizó la incidencia de enfermedad cardiovascular, hipertensión arterial y la ganancia de peso a lo largo de un seguimiento máximo de 6 años. Se ajustaron modelos de regresión de Cox para estimar hazard ratios (riesgos relativos [RR]) tras ajustar por posibles factores de confusión. Resultados: El consumo de jamón en los niveles más altos (> 4 raciones/semana) no presentaba asociación con la incidencia de eventos cardiovasculares (RR=1,02; [IC 95%: 0,44-2,39]), tras ajustar por edad, sexo, ingesta energética total y patrón dietético, en comparación con los consumos inferiores a una vez por semana. Al repetir esta comparación para la hipertensión, y tras ajustar por edad, sexo, ingesta energética total e índice de masa corporal, se encontró un RR = 0.74 (IC 95%: 0.55-1.01). En la comparación del cambio de peso medio anual entre estas mismas categorías extremas de consumo (=4 raciones) se encontró una diferencia no significativa de 0,033 kg (IC 95%: -0,041 a +0,107) en la ganancia media de peso al año tras ajustar por sexo, edad, tabaco, actividad física e índice de masa corporal inicial. Conclusiones: Los resultados de esta cohorte no proporcionan evidencia de que el consumo de jamón curado se asocie a mayor riesgo cardiovascular, de hipertensión arterial o de ganancia de peso.Background and objective: Cured ham is a characteristic food in Spanish Mediterranean diet. However, no prospective epidemiologic study assessing its effects on human health is available. Our aim was to assess the association between the consumption of cured ham and cardiovascular disease, hypertension or weight gain. Subjects and Method: In a prospective and dynamic epidemiologic cohort composed exclusively of university graduates (the SUN Project, n=13,293), we analyzed the incidence of cardiovascular disease, hypertension or average yearly weight gain after a maximum follow-up of 6 years. Cox (proportional hazards) regression models were fitted to estimate hazard ratios (relative risks [RR]) after adjusting for potential confounding. Results: No association was found between higher levels of consumption of cured ham (> 4 servings/week) and the incidence of cardiovascular disease (RR=1.02; [95%CI]: 0.44-2.39), in analyses adjusted for age, sex, total energy intake and dietary pattern, compared to the consumption of less than one serving a week. When we repeated this comparison for the incidence of hypertension, and adjusting for age, sex, total energy intake and body mass index, the RR was 0.74 (95% CI: 0.55-1.01). In the comparison of average yearly weight gain between these extreme categories of cured ham consumption (=4 servings/week) a non-significant difference of 0.033 kg (95% CI: -0.041 to 0.107) was found after adjusting for sex, age, smoking, physical activity, and baseline body mass index. Conclusions: The results of this cohort study do not support any association between the consumption of cured ham and a higher risk of cardiovascular disease, hypertension or weight gain

Observational constraints to boxy/peanut bulge formation time

Boxy/peanut bulges are considered to be part of the same stellar structure as bars and both could be linked through the buckling instability. The Milky Way is our closest example. The goal of this letter is determining if the mass assembly of the different components leaves an imprint in their stellar populations allowing to estimate the time of bar formation and its evolution. To this aim we use integral field spectroscopy to derive the stellar age distributions, SADs, along the bar and disc of NGC 6032. The analysis shows clearly different SADs for the different bar areas. There is an underlying old (>=12 Gyr) stellar population for the whole galaxy. The bulge shows star formation happening at all times. The inner bar structure shows stars of ages older than 6 Gyrs with a deficit of younger populations. The outer bar region presents a SAD similar to that of the disc. To interpret our results, we use a generic numerical simulation of a barred galaxy. Thus, we constrain, for the first time, the epoch of bar formation, the buckling instability period and the posterior growth from disc material. We establish that the bar of NGC 6032 is old, formed around 10 Gyr ago while the buckling phase possibly happened around 8 Gyr ago. All these results point towards bars being long-lasting even in the presence of gas.Comment: Accepted for publication in MNRAS Letter

Preparation of Dipteran Larvae for Scanning Electron Microscopy with Special Reference to Myiasigen Dipteran Species

Although controversy exists concerning the role of chemical fixatives in scanning electron microscopy (SEM) studies of Dipteran larvae, we have observed that filtered 10% formaldehyde solution gives excellent results as a preservative. After immersing in vivo in formaldehyde, the larvae material is preserved for prolonged periods (up to 8 months), before examination with SEM. As a fixative, formaldehyde preserves the structure of the larval cuticle and produces no visible artifacts. Moreover, postfixation is not necessary. Due to pecularities of the way of life of Wohlfahrtia magnifica (principally the accumulations of necrotic tissue, purulent particles, and other types of substances that often adhere to the numerous spines of larvae), this species must be cleaned before examination by SEM. Manual cleaning with alternating bidistilled water and 0.9% saline solution proved to be a rapid, easy and inexpensive method that gave good results. Both lyophilization drying and critical point drying were used before sputtering the material. While lyophilization drying proved to be the most effective method for instars II and III, critical point drying was the best technique for study of specimens belonging to instar I. The optimum time for drying and conditions for lyophilization and sputter-coating with gold were determined experimentally. Samples were mounted on SEM stubs with double-sided adhesive and silver conductive paint. The method proposed is easy and effective for the SEM study of larvae myiasis-producing diptera