808 research outputs found

    Política De Alimentação Escolar Brasileira: Representações Sociais E Marcas Do Passado

    Get PDF
    The Programa Nacional de Alimentação Escolar (PNAE) is a Brazilian public policy initiative regulated by the Education Ministry and aimed, in a universal manner, at the scholastic environment, with supplementary nutrition and nutritional education in public academic institutions as its primary focus. However, student participation is low. Brazilian school food programs have traditionally been known as merenda escolar, a designation acquired within the context of its creation in 1955 that continues to be commonly used in schools today. The present text seeks to demonstrate that the strong welfare-oriented traditional context in which school food programs in Brazil appeared left lasting marks on the social representation of this school meal and consequently hindered its universal implantation. Based on this premise, two simultaneous methodological processes were developed. One was a qualitative study carried out among students, administrators, and food service workers designed to characterize the social representations of those involved. The other involved the use of historical policy documents in order to discern some of the roots of the social representations present today (Moscovici, 2011). The results indicate that despite improvements in nutritional quality and in the process through which school meals are provided, contradictions exist between regulatory theory and the daily practices carried out in schools, and that these inconsistencies are heightened by an inadequate implementation of the meal program. In addition, the study found that students from less privileged socio-economic classes take the most frequent advantage of the school food program, a fact which indicates that this program’s social representation has yet to overcome its past association with public welfare. © 2016, Arizona State University. All rights reserved.2

    On the importance of relative permeability data for estimating CO2 injectivity in brine aquifers

    Get PDF
    Performance assessment of possible CO2 storage schemes is often investigated through numerical simulation of the CO2 injection process. An important criterion of interest is the maximum sustainable injection rate. Relevant numerical models generally employ a multi-phase extension to Darcy's law, requiring data concerning the evolution of relative permeability for CO2 and brine mixtures with increasing CO2 saturation. Relative permeability data is acutely scarce for many geographical regions of concern and often cited as a major source of uncertainty. However, such data is expensive and time consuming to acquire. With a view to improving our understanding concerning the significance of relative permeability uncertainty on injectivity, this article presents a sensitivity analysis of sustainable CO2 injection rate with respect to permeability, porosity and relative permeability. Based on available relative permeability data obtained from 25 sandstone and carbonate cores discussed in the literature, injectivity uncertainty associated with relative permeability is found to be as high as ±57% for open aquifers and low permeability closed aquifers (100 mD), aquifer compressibility plays a more important role and the uncertainty due to relative permeability is found to reduce to ±6%

    BCS theory for s+g-wave superconductivity borocarbides Y(Lu)Ni2_2B2_2C

    Full text link
    The s+g mixed gap function \Delta_k=\Delta {[(1-x)-x\sin^4\theta\cos4\phi]} (x: weight of g-wave component) has been studied within BCS theory. By suitable consideration of the pairing interaction, we have confirmed that the coexistence of s- and g-wave, as well as the state with equal s and g amplitudes (i.e., x=1/2) may be stable. This provides the semi-phenomenological theory for the s+g-wave superconductivity with point nodes which has been observed experimentally in borocarbides YNi_2B_2C and possibly in LuNi_2B_2C.Comment: 5 pages, 3 figure

    Neutral Pions and Eta Mesons as Probes of the Hadronic Fireball in Nucleus-Nucleus Collisions around 1A GeV

    Full text link
    Chemical and thermal freeze-out of the hadronic fireball formed in symmetric collisions of light, intermediate-mass, and heavy nuclei at beam energies between 0.8A GeV and 2.0A GeV are discussed in terms of an equilibrated, isospin-symmetric ideal hadron gas with grand-canonical baryon-number conservation. For each collision system the baryochemical potential mu_B and the chemical freeze-out temperature T_c are deduced from the inclusive neutral pion and eta yields which are augmented by interpolated data on deuteron production. With increasing beam energy mu_B drops from 800 MeV to 650 MeV, while T_c rises from 55 MeV to 90 MeV. For given beam energy mu_B grows with system size, whereas T_c remains constant. The centrality dependence of the freeze-out parameters is weak as exemplified by the system Au+Au at 0.8A GeV. For the highest beam energies the fraction of nucleons excited to resonance states reaches freeze-out values of nearly 15 %, suggesting resonance densities close to normal nuclear density at maximum compression. In contrast to the particle yields, which convey the status at chemical freeze-out, the shapes of the related transverse-mass spectra do reflect thermal freeze-out. The observed thermal freeze-out temperatures T_th are equal to or slightly lower than T_c, indicative of nearly simultaneous chemical and thermal freeze-out.Comment: 42 pages, 12 figure

    Covariation between the shape and mineralized tissues of the rib cross section in Homo sapiens, Pan troglodytes and Sts 14

    Get PDF
    Objectives: Studying rib torsion is crucial for understanding the evolution of the hominid ribcage. Interestingly, there are variables of the rib cross section that could be associated with rib torsion and, consequently, with the morphology of the thorax. The aim of this research is to conduct a comparative study of the shape and mineralized tissues of the rib cross section in different hominids to test for significant differences and, if possible, associate them to different thoracic morphotypes.Materials and Methods: The sample consists of the rib cross sections at the midshaft taken from 10 Homo sapiens and 10 Pan troglodytes adult individuals, as well as from A. africanus Sts 14. The shape of these rib cross sections was quantified using geometric morphometrics, while the mineralized tissues were evaluated using the compartmentalization index. Subsequently, covariation between both parameters was tested by a Spearman's ? test, a permutation test and a linear regression.Results: Generally, P. troglodytes individuals exhibit rib cross sections that are rounder and more mineralized compared to those of H. sapiens. However, the covariation between both parameters was only observed in typical ribs (levels 3-10). Although covariation was not found in the rib cross sections of Sts 14, their parameters are closer to P. troglodytes.Discussion: On the one hand, the differences observed in the rib cross sections between H. sapiens and P. troglodytes might be related to different degrees of rib torsion and, consequently, to different thoracic 3D configurations. These findings can be functionally explained by considering their distinct modes of breathing and locomotion. On the other hand, although the rib cross sections belonging to Sts 14 are more similar to those of P. troglodytes, previous publications determined that their overall morphology is closer to modern humans. This discrepancy could reflect a diversity of post-cranial adaptations in Australopithecus

    Black hole mass and angular momentum in 2+1 gravity

    Get PDF
    We propose a new definition for the mass and angular momentum of neutral or electrically charged black holes in 2+1 gravity with two Killing vectors. These finite conserved quantities, associated with the SL(2,R) invariance of the reduced mechanical system, are shown to be identical to the quasilocal conserved quantities for an improved gravitational action corresponding to mixed boundary conditions. They obey a general Smarr-like formula and, in all cases investigated, are consistent with the first law of black hole thermodynamics. Our framework is applied to the computation of the mass and angular momentum of black hole solutions to several field-theoretical models.Comment: 23 pages, 3 references added, to be published in Physical Review

    Impurity effects on s+g-wave superconductivity in borocarbides Y(Lu)Ni_2B_2C

    Full text link
    Recently a hybrid s+g-wave pairing is proposed to describe the experimental observation for a nodal structure of the superconducting gap in borocarbide YNi2_2B2_2C and possibly LuNi2_2B2_2C. In this paper the impurity effects on the s+g-wave superconductivity are studied in both Born and unitarity limit. The quasiparticle density of states and thermodynamics are calculated. It is found that the nodal excitations in the clean system are immediately prohibited by impurity scattering and a finite energy gap increases quickly with the impurity scattering rate. This leads to an activated behavior in the temperature dependence of the specific heat. Qualitative agreement with the experimental results is shown. Comparison with d-wave and some anisotropic s-wave studied previously is also made.Comment: 6 pages, 6 eps figure

    Spatio-temporal assessment of beech growth in relation to climate extremes in Slovenia – An integrated approach using remote sensing and tree-ring data

    Get PDF
    Climate change is predicted to affect tree growth due to increased frequency and intensity of extreme events such as ice storms, droughts and heatwaves. Yet, there is still a lot of uncertainty on how trees respond to an increase in frequency of extreme events. Use of both ground-based wood increment (i.e. ring width) and remotely sensed data (i.e. vegetation indices) can be used to scale-up ground measurements, where there is a link between the two, but this has only been demonstrated in a few studies. We used tree-ring data together with crown features derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) to assess the effect of extreme climate events on the growth of beech (Fagus sylvatica L.) in Slovenia. We found evidence that years with climate extremes during the growing season (drought, high temperatures) had a lower ring width index (RWI) but we could not find such evidence for the remotely sensed EVI (Enhanced Vegetation Index). However, when assessing specific events where leaf burning or wilting has been reported (e.g. August 2011) we did see large EVI anomalies. This implies that the impact of drought or heatwave events cannot be captured by EVI anomalies until physical damage on the canopy is caused. This also means that upscaling the effect of climate extremes on RWI by using EVI anomalies is not straightforward. An exception is the 2014 ice storm that caused a large decline in both RWI and EVI. Extreme climatic parameters explained just a small part of the variation in both RWI and EVI by, which could indicate an effect of other climate variables (e.g. late frost) or biotic stressors such as insect outbreaks. Furthermore, we found that RWI was lower in the year after a climate extreme occurred in the late summer. Most likely due to the gradual increase in temperature and more frequent drought we found negative trends in RWI and EVI. EVI maps could indicate where beech is sensitive to climate changes and could be used for planning mitigation interventions. Logical next steps should focus on a tree-based understanding of the short -and long-term effects of climate extremes on tree growth and survival, taking into account differential carbon allocation to the crown (EVI) and to wood-based variables. This research highlights the value of an integrated approach for upscaling tree-based knowledge to the forest level

    In-planta transient transformation of avocado (Persea americana) by vacuum agroinfiltration of aerial plant parts

    Get PDF
    Avocado, Persea americana Mill, is one of the most traded tropical fruits in the international market. To date, stable and transient transformation has only been achieved for of zygotic embryos and not of adult plant tissue, which limits functional genomics research. We provide the first transient Agrobacterium-mediated transformation methodology in avocado leaves that overcomes the recalcitrance to transformation of this species. We investigated the effect of Agrobacterium strain, leaf stage, wounding pre-treatment, the phytohormone jasmonic acid, and vacuum infiltration on transient transformation of avocado leaves. Using the Agrobacterium strain LBA4404 and the RUBY reporter a transformation frequency of up to 27% was obtained for avocado detached leaves. The transformation efficiency depended on the age of the leaf, with an intermediate stage of leaf development showing the highest efficiency of transient reporter gene expression. Microwounding pre-treatment facilitates agroinfiltration and coupled with leaf age are the primary factors influencing competence for transient transformation. Jasmonic acid did not significantly affect transient transformation in the absence of microwounding. However, microwounding and 250 µM of jasmonic acid acted synergistically to significantly enhance transient expression. Using this methodology with localized vacuum agroinfiltration, transient transformation of attached avocado leaves was achieved. This method unlocks the use of Agrobacterium-mediated transient transformation as a tool for explore gene function and metabolic pathways in both, detached and attached avocado leaves
    corecore