511 research outputs found
Structural and optical studies of FeSb2 under high pressure
Nanostructured orthorhombic FeSb2 and an amorphous phase were formed by
mechanical alloying starting from a mixture of high purity elemental Fe and Sb
powders. The effects of high pressures on structural and optical properties
were studied using X-ray diffraction (XRD) and Raman spectroscopy (RS). XRD
patterns showed the presence of the orthorhombic FeSb2 phase up to the maximum
pressure applied (28.2 GPa). The XRD patterns showed also an increase in the
amount of the amorphous phase with increasing pressure up to 23.3 GPa. At 14.3
GPa, together with the former phases, a new phase was observed and indexed to a
tetragonal FeSb2 phase, but its volume fraction is small at least up to 23.3
GPa. For the orthorhombic FeSb2 phase, the pressure dependence of the volume
fitted to a Birch-Murnaghan equation of state gave a bulk modulus = 74.2 +- 3.0
GPa and its pressure derivative = 7.5 +- 0.6. RS measurements were performed
from atmospheric pressure up to 45.2 GPa. For the orthorhombic FeSb2 phase, the
Raman active mode was observed up to the maximum pressure applied, while the
mode disappeared at 16.6 GPa. For pressures higher than 21 GPa, the Raman
active mode of a tetragonal FeSb2 phase was observed, confirming ab initio
calculations reported in the literature.Comment: 31 pages, 11 figures and 2 tables. Already submitted for publicatio
Metabolic syndrome before puberty: Myth or reality?
Metabolic syndrome (MetS) is defined as a cluster of alterations related with insulin resistance (obesity, dyslipidemia, hypertension, and impaired glucose metabolism), which are associated with a higher risk of cardiovascular disease in adults. Several definitions have been proposed for older children and adolescents. However, no definitions have been made in accordance with pubertal status, and those in prepubertal state have not received attention enough, despite there are data suggesting the early presence of risk factors. The new insights concerning healthy and unhealthy metabolic status or the addition of novel metabolic risk biomarkers, may contribute to the knowledge about the development of MetS in children. This manuscript reviews the available evidence on MetS during childhood, focusing on the prepubertal period
Does human education integrate full-time education? What pedagogical practices tell us?
O artigo aborda como a formação humana pode integrar a educação integral nos contextos de resistência à estrutura escolar, em que tempos e espaços cindidos promovem reprodução de relações desumanizantes. Com uma abordagem qualitativa da pesquisa, contextualizou-se política e conceitualmente o tema. Em seguida, foi feito o registro narrativo da experiência com alfabetização de uma professora de escola pública para refletir sobre como as dimensões ética e estética podem se materializar na educação integral. Essa materialização indica a potência de recriação do trabalho pedagógico como ato responsável para o reconhecimento das crianças como autoras de seu processo de aprendizagem.39108177192The article discusses how human education can integrate full-time education in contexts of resistance to school structure in which split time and spaces promote the reproduction of dehumanizing relationships. Using a qualitative approach, the topic is contextualized politically and conceptually. Furthermore, there is a narrative record of literacy experience in a public school in order to reflect on how ethical and aesthetic dimensions can be materialized in fulltime education. This materialization indicates the power of re-creation of pedagogical practice as a responsible act for the recognition of children as authors in their own learning process
Application of shallow seismic profiling to study riverbed architectural facies: a case study of the Tocantins river (Pará - Brazil)
To date, the vast majority of river sedimentology study has relied on two main categories of observation: direct observation of shallow trenches, cut faces and cores or geophysical survey on dry and shallow regions of braid bars. In this study, a sub-bottom profiler was used to investigate the stratigraphy of the lower course of the Tocantins River in the Amazon region, between the city of Tucuruì and the village of Nazaré dos Patos. The interest in this specific region lies on the possible variation of the fluvial regime due to the installation of the dam of the Tucuruì hydroelectric plant and the perspective that such river would become navigable as soon as the canal lock will be completed. Collected data show a detailed variety and complexity of architectural elements, as well as internal structure of sandy macroforms. Furthermore, the results allowed the identification of three main environments linked to channel sedimentation processes: by-pass, transition and deposition environments, whose distribution is linked to channel dynamics and bedrock topography. The application of the study is manifold, once it provides not only an insight into sedimentary structure of alluvial forms and sedimentation history, but also elements demanded to plan eventual engineering works for river navigability.Até hoje, a maior parte dos estudos de sedimentologia fluvial tem adotado dois principais métodos de investigação: observação direta de trincheiras, faces expostas e testemunhos, ou levantamento geofísico nas regiões emersas ou rasas das barras fluviais. Neste estudo, um perfilador acústico de subfundo foi utilizado para investigar a estratigrafia do baixo curso do Rio Tocantins, na bacia Amazônica, entre a cidade de Tucuruí e a vila de Nazaré dos Patos. O interesse neste trecho do rio reside na possível variação do regime fluvial devido à instalação da barragem da usina hidrelétrica de Tucuruí e à perspectiva de que este rio se torne navegável após a conclusão da construção da eclusa. Os perfis coletados mostram detalhes da variedade e complexidade de elementos arquiteturais e a estrutura interna das macroformas arenosas. Além disso, os resultados permitiram a identificação de três ambientes correlacionados com os processos sedimentares ativos no canal: ambientes de by-pass, transição e deposição, que estão relacionados à dinâmica do canal e topografia do embasamento. A aplicação deste estudo é multíplice, uma vez que fornece informações sobre a estrutura sedimentar das formas aluvionais e histórico de deposição, mostra elementos necessários ao planejamento de eventuais intervenções para a navegabilidade do rio
Cardiovascular risk biomarkers and metabolically unhealthy status in prepubertal children: Comparison of definitions
Background and aims: The early onset of cardio-metabolic abnormalities, known as metabolically unhealthy (MU) status, is highly associated with obesity and cardiovascular disease (CVD), as well as with increased morbidity and mortality later in life. Given the lack of a consensus MU classification for prepubertal children, we aimed to compare available MU definitions in terms of their association with CVD risk biomarkers.
Methods and results: A total of 930 prepubertal children (622 with overweight/obesity, 462 males) aged 5–10.9 years were recruited, anthropometric measures were taken and biomarkers were analyzed. Children were classified using eight MU definitions based on different cut-offs for blood pressure, triacylglycerides, high-density lipoprotein cholesterol, glucose and homeostasis model assessment for insulin resistance (HOMA-IR). MU prevalence in children with overweight/obesity ranged between 30% and 60% across definitions. Plasma concentrations of resistin, leptin, myeloperoxidase (MPO) and total plasminogen activator inhibitor 1 (tPAI-1) were higher, and those of adiponectin were lower, in MU compared to MH children with overweight/obesity. Linear regression analyses confirmed the contribution of MPO and tPAI-1 concentrations to MU status, with most significant results derived from definitions that use age and sex-specific criteria and that account for HOMA-IR.
Conclusion: Plasma concentrations of MPO and tPAI-1 are increased in prepubertal MU children irrespective of having normal-weight or overweight/obesity. Inclusion of age and sex-specific cut-offs for cardio-metabolic components as well as insulin resistance criteria increases the quality of MU definitions as seen by their stronger association with CVD biomarkers concentrations
Spatial exploration of Streptococcus pneumoniae clonal clustering in São Paulo, Brazil
OBJECTIVES: To examine the spatial distribution of Streptococcus pneumoniae and its clonal patterns collected between 2002 and 2006 in São Paulo, Brazil. METHODS: As part of an observational study in São Paulo city, Brazil, S. pneumoniae isolates routinely cultured from blood, respiratory specimens, or cerebrospinal and other profound fluids were selected. Additionally, only isolates with either penicillin (PEN) intermediate (I) or resistant (R) status on routine antibiogram were included, in order to obtain a higher probability of clonal isolates. A single I/R S. pneumoniae isolate per patient was included and submitted to genotypic determination by pulsed field gel electrophoresis (PFGE). Minimum inhibitory concentrations (MICs) were determined for the isolates by Etest® to PEN and other antimicrobials. Each isolate was geocoded in a digital map. The Kernel function and ratio methods between total isolates vs. clones were used in order to explore possible cluster formations. RESULTS: Seventy-eight (78) S. pneumoniae community isolates from two major outpatient centers in São Paulo, Brazil, were selected from the databank according to their penicillin susceptibility profile, i.e. R or I to penicillin assessed by oxacillin disc diffusion. Of these, 69 were submitted to PFGE, 65 to MIC determination, and 48 to spatial analytical procedures. Preliminary spatial analysis method showed two possible cluster formation located in southwest and southeast regions of the city. CONCLUSION: Further analyses are required for precisely determining the existence of S. pneumoniae clusters and their related risk factors. Apparently there is a specific transmission pattern of S. pneumoniae clones within certain regions and populations. GIS and spatial methods can be applied to better understand epidemiological patterns and to identify target areas for public health interventions.Universidade Federal de São Paulo (UNIFESP) Special Laboratory of Clinical MicrobiologyHospital Israelita Albert EinsteinGC-2 Gestão do Conhecimento Científico LtdInstituto Nacional de Pesquisas Espaciais Department of Image ProcessingUNIFESP, Special Laboratory of Clinical MicrobiologySciEL
A Cantelli-type inequality for constructing non-parametric p-boxes based on exchangeability.
In this paper we prove a new probability inequality that
can be used to construct p-boxes in a non-parametric
fashion, using the sample mean and sample standard
deviation instead of the true mean and true standard deviation.
The inequality relies only on exchangeability
and boundedness
The effects of field inoculation of arbuscular mycorrhizal fungi through rye donor plants on grapevine performance and soil properties
Grapevines are highly dependent on arbuscular mycorrhizal fungi (AMF) for normal growth and development. However, vineyard soils may have low AMF abundance and diversity due to conventional soil management practices that are detrimental for these fungi. In this context, the establishment of AMF-inoculated cover crops can be a highly convenient strategy to reestablish soil mycorrhizal potential, as it combines the advantages of a vigorous inoculum source coming from mycorrhizal donor plants with the overall benefits of green covers for grape quality, microbial diversity and soil health. In this work, the potential benefits of Funneliformis mosseae-inoculated under-vine cover crops on grapevine growth, physiology and production were compared to those derived from 1) the establishment of non-inoculated under-vine cover crops, and 2) conventional herbicide-based weed control in the under-vine space. In addition, grapevine root AMF community composition was analyzed to assess if the introduction of a non-native AMF species induced changes on resident mycorrhizal community assemblies and to unveil potential variations in AMF diversity associated to herbicide replacement by green covers. Results indicated that under-vine cover crops, inoculated or not, led to a general vigor decrease in grapevines, probably due to competition between the two species. However, after a heat wave that occurred at harvest time in the second year of the experiment, grapevines growing in plots with inoculated cover crops had the highest photochemical reflectance indices and net photosynthesis rates, and partially compensated production losses due to berry sunburn. Root mycorrhizal community analysis by the end of the experiment revealed that the inoculated F. mosseae isolate colonized grapevine roots from inoculated plots, while it was absent in the other ones. Moreover, inoculation of this AMF did not lead to a replacement of native root AMF communities, but allowed further colonization by other resident Glomeraceae and non-Glomeraceae AMF taxa. Overall, the work herein demonstrates that the introduction of F. mosseae through donor plants is a suitable field inoculation method for grapevines and can help them to better withstand heat wavesinfo:eu-repo/semantics/submittedVersio
Composition Of ω-3 And ω-6 Fatty Acids In Freeze-dried Chicken Embryo Eggs With Different Days Of Development
Fatty acids ω-3 and ω-6 composition and specially DHA were determined in freeze-dried chicken embryo eggs with pre-determined incubation periods. Fertile and embryo eggs presented palmitic (23.18 ± 0.54%), stearic (7.70 ± 0.28%), palmitoleic (3.00 ± 0.19%), oleic (36.28 ± 0.58%), linoleic (22.18 ± 0.34%), linolenic (1.08 ± 0.04%), arachidonic (2.04 ± 0.03%), docosahexaenoic (0.91 ± 0.03%), total ω-3 acids (2.26 ± 0.10%) and total ω-6 acids (24.62 ± 0.33%). There were no significant differences in total contents of ω-3 fatty acids (p=0.1226) between freeze-dried chicken embryo eggs with different incubation periods (3, 5, 7, 9, and 11 days) and fertile freeze-dried chicken eggs (day 0). However, there were significant differences in total medium contents of ω-6 fatty acids (P=0.001). There was also a strong statistical evidence that quadratic model was related with expected values of DHA content (p= 0.0013).472219224Abril, R., Barclay, B., Fatty acid analysis of poultry eggs as methyl esters (1999) Método OT-GCPE, Rev. 3.1, , OmegaTech. Bolder, Co. 24/03/99(1996) Official Methods and Recommended Practices of de American Oil Chemists' Society. 4th Ed., , American Oil Chemists' Society, Champaign IIBragagnolo, N., Turatti, J.M., Evaluation of "light" eggs in Brazil (1999) Associazione Italiana di Avicoltura Scientifica, Instituto di Zootecnia, 2, pp. 177-181. , Paper presented at VIII European Symposium on the Quality of Eggs and Eggs Products, Bologna, ItáliaBeig, D., Garcia, F.C.M., (1986) O Embrião de Galinha, , Campo Grande : UFMS/ Imprensa UniversitáriaCherian, G., Sim, J.S., Net transfer and incorporation of yolk n-3 fatty acids into developing chick embryos (1993) Poultry Science, 72, pp. 98-105Cherian, G., Gopalakrishnan, N., Akiba, Y., Sim, J.S., Effect of maternal dietary n-3 fatty acids on the accretion of long-chain polyunsaturated fatty acids in the tissues of developing chick embryo (1997) Biology of Neonate, 72, pp. 165-174Connor, W.E., Importance of n-3 fatty acids in health and disease (2000) American Journal of Clinical Nutritional, 71 (SUPPL.), pp. 171S-175SFarkas, K., Noble, R.C., Speake, B.K., Development changes in the levels of molecular species of triacylglicerol that contain docosahexaenoic acid in adipose tissue of chick embryo (1996) Comparative Biochemistry and Physiology B-Biochemistry and Molecular Biology, 115, pp. 1-6Ferrier, L.K., Gaston, L.J., Leeson, S., Squires, J., Weaver, B.J., Holub, B.J., α-linolenic acid - and docosahexaenoic acid - enriched eggs from hens fed flaxseed: Influence on blood lipids and platelet phospholipid fatty acids in human (1995) The American Journal of Clinical Nutrition, 62, pp. 81-86Lin, D.S., Connor, W.E., Anderson, G.J., The incorporation of n-3 and n-6 essential fatty acids into chicken embryo from eggs yolks having vastly different fatty acid compositions (1991) Pediatric Research, 29, pp. 601-605Maldjian, A., Falkas, K., Noble, R.C., Cocchi, M., Speake, B.K., The transfer of docosahexaenoic acid from the yolk to the tissues of chicken embryo (1995) Biochimica et Biophysica Acta, 1258, pp. 81-99Nettleton, J.A., (1995) Omega-3 Fatty Acids and Health, , Chapman and Hall, New YorkNoble, R.C., Cocchi, M., Lipid metabolism and the neonatal chicken (1990) Prog. Lipid Res., 29, pp. 107-140Park, Y.K., Koo, M.H., Carvalho, P.O., Recentes Progresses dos Alimentos Funcionais (1997) Bol. SBCTA, 31Salatin, J., Pastured poultry profits (1993) Polyface Swoope, , VirginiaSpeake, B.K., Murray, A.M.B., Noble, R.C., Transport and transformations of yolk lipids during development of avian embryo (1998) Prog. Lipid Res., 37, pp. 1-32Stadelman, W.J., Pratt, D.E., Factors influencing composition the hen's egg (1989) World's Poultry Science Journal, 45, pp. 247-261Thapon, J.L., Bourgeois, C.M., L'oeuf et les ovoproduits (1994) Lavoisier -Technique et Documentation, , ParisVieira, S., Hoffmann, R., Estatísitica experimental (1989) Atlas, , São Paul
Evaluation of Sedentary Behavior and Physical Activity Levels Using Different Accelerometry Protocols in Children from the GENOBOX Study
Background Physical activity (PA) has acquired a significant relevance due to the health benefits associated with its practice. Accelerometers are an effective tool to assess PA; however, the diversity of cut-off points used to define different PA intensities through accelerometry could interfere in the interpretation of the findings among studies. Objectives The present study aimed to examine the sedentary behavior (SB) and physical activity (PA) levels in children using six selected accelerometry protocols based on diverse cut-off points. Methods Clinical examination, anthropometric measurements, and PA evaluation by accelerometry were assessed in 543 selected children (10 +/- 2.4 years old) from the Spanish GENOBOX study. The ActiLife data scoring program was used to determine daily min spent in SB, and light, moderate, vigorous and moderate-vigorous PA using six validated accelerometry protocols differing in their cut-off points. Results Very different estimations for SB and PA intensity levels were found in children, independently of the non-wear-time algorithm selected, and considering puberty stages, age and body mass index. The time spent in daily SB varied from 471 to 663.7 min, PA ranged from 141 to 301.6 min, and the moderate-vigorous PA was reported between 20.7 and 180.2 min. Conclusion The choice of a particular accelerometry protocol considering these factors is important to evaluate SB or PA intensities to suit the characteristics of the sample researched. It seems necessary to establish future lines of research that include different analytical approaches to measure SB and PA by accelerometry based on standardized and validated methodology
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