Listar Ciencias Exactas y Naturales por título
Mostrando ítems 4079-4098 de 5964
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A premissa metafísica da revolução copernicana
(2002) [Artículo de periódico]Resumo não disponível -
Preparação e avaliação térmica e reológica de misturas de PEBD/PELBD
(2002) [Artículo de periódico]Misturas de Polietileno de Baixa Densidade (PEBD) com diferentes tipos e proporções de Polietilenos Lineares de Baixa Densidade (PELBD) foram preparadas em extrusora de rosca simples e dupla a fim de verificar a influência ... -
Preparation, cation-anion interactions and physicochemical properties of ether-functionalized imidazolium ionic liquids
(2008) [Artículo de periódico]Uma série de líquidos iônicos 1-alquil éter (e 1-alquil)-3-metilimidazólio 2-4 ([CxOyMIm]+[Ânion]− ou [CxMIm]+[Ânion]−, onde MIm = 3-metilimidazólio; CxOy = 1-alquil éter, C7O3 = -(CH2)2O(CH2)2O(CH2)2OCH3 (A), C3O1 = ... -
Preparation of (5R)-4,8-dimethylbicyclo[3.3.0]oct-1(8),3-dien-2-one from (-)-limonene oxide : a novel intermediate to the synthesis of 4-5-5 fused tricarbocyclic core present in terpenic natural products
(2004) [Artículo de periódico]Este trabalho refere-se à síntese enantiosseletiva da dienona (5R)-4,8-dimethylbicyclo[3.3.0]oct- 1(8),3-dien-2-one. Este intermediário, pode ser reconhecido como um bloco de construção versátil para a síntese de uma grande ... -
Presença de informações sobre governança de TI nos relatórios anuais de empresas brasileiras de grande porte
(2011) [Artículo de periódico]Este artigo analisa o espaço que as organizações brasileiras de grande porte têm dado ao tema da governança de TI em seus Relatórios Anuais (RA) através do levantamento da presença de informações sobre ele nesses documentos. ... -
Pressão e volume em balões de festa : podemos confiar em nossa intuição?
(2004) [Artículo de periódico]Dois balões, ambos com o mesmo tamanho original e desigualmente inflados, são conectados às extremidades de uma mangueira, na qual uma obstrução impede a passagem de ar. Demonstra-se que, quando a obstrução é removida, o ... -
Pressure and chemical substitution effects in the local atomic structure of BaFe2As2
(2011) [Artículo de periódico]The effects of K and Co substitutions and quasihydrostatic applied pressure (P < 9 GPa) in the local atomic structure of BaFe2As2, Ba(Fe0.937Co0.063)2As2 and Ba0.85K0.15Fe2As2 superconductors were investigated by extended ... -
Pressure dependence of the refractive index of monoclinic and yttria-stabilized cubic zirconia
(1995) [Artículo de periódico]The pressure dependence of the refractive index of monoclinic and yttria-stabilized cubic zirconia was measured up to 3 and 8 GPa, respectively, using an interferometric method with the diamond-anvil cell. The experimental ... -
Pressure-induced phase transitions and volume changes in Hf02 up to Gpa
(1993) [Artículo de periódico]The phase transformations and pressure-volume dependence of Hf02 have been investigated at room temperature by angle-dispersive powder x-ray diffraction under high pressure to 50 GPa in a diamond anvil cell. The phase ... -
Pressure-induced self-insertion reaction in CoSb/sub 3/
(2007) [Artículo de periódico]The thermoelectric material CoSb3, with skutterudite structure, was subjected to high pressures using a diamond anvil cell up to 40 GPa. Above 20 GPa this compound undergoes an irreversible isosymmetric transition to a ... -
Pressure-induced structural phase transitions in zirconia under high pressure
(1993) [Artículo de periódico]Angular-dispersive x-ray in situ powder-diffraction experiments have been performed on pure zirconia, Zr02, at room temperature under high pressure up to 50 GPa. Under increasing pressure four phases were successively ... -
Pressure induced water insertion in the defect pyrochlore nh/sub 4/nbwo/sub 6/
(1997) [Artículo de periódico]A sudden and reversible increase of about 5% in the unit cell volume of ammonium tungstoniobate at pressures around 2.5 GPa was observed with pressure transmitting media containing water. This behavior was attributed to ... -
Pressure-support ventilation or T-piece spontaneous breathing trials for patients with chronic obstructive pulmonary disease : a randomized controlled trial
(2018) [Artículo de periódico]Background Little is known about the best strategy for weaning patients with chronic obstructive pulmonary disease (COPD) from mechanical ventilation. Spontaneous breathing trials (SBT) using a T-piece or pressure-support ... -
Prevalence and acquisition of MRSA amongst patients admitted to a tertiary-care hospital in Brazil
(2010) [Artículo de periódico]Background: There are few studies in Brazil that address baseline prevalence of MRSA colonization and associated risk factors at hospital admission, or the incidence of nosocomial colonization. We report a prospective study ... -
Prevalence, correlates, and description of self-reported diabetes in brazilian capitals : results from a telephone survey
(2014) [Artículo de periódico]Introduction: The prevalence of diabetes is increasing worldwide. The objective of this study is to estimate the prevalence of self-reported diabetes in Brazilian adults and to describe its population correlates as well ... -
Prevalence of common α-thalassemia determinants in south Brazil : importance for the diagnosis of microcytic anemia
(2010) [Artículo de periódico]Alpha thalassemia has not been systematically investigated in Brazil. In this study, 493 unrelated individuals from the southernmost Brazilian state of Rio Grande do Sul were screened for deletional forms of -thalassemia. ... -
Prevalence of ERα-397 PvuII C/T, ERα-351 XbaI A/G and PGR PROGINS polymorphisms in Brazilian breast cancer-unaffected women
(2012) [Artículo de periódico]Polymorphisms of hormone receptor genes have been linked to modifications in reproductive factors and to an increased risk of breast cancer (BC). In the present study, we have determined the allelic and genotypic frequencies ... -
Prevalence of the BRCA1 founder mutation c.5266dup in brazilian individuals at-risk for the hereditary breast and ovarian cancer syndrome
(2011) [Artículo de periódico]About 5-10% of breast and ovarian carcinomas are hereditary and most of these result from germline mutations in the BRCA1 and BRCA2 genes. In women of Ashkenazi Jewish ascendance, up to 30% of breast and ovarian carcinomas ... -
Prevalence of the STK15 F31I polymorphism and its relationship with mammographic density
(2011) [Artículo de periódico]Several studies have identified the single nucleotide polymorphism STK15 F31I as a low-penetrance risk allele for breast cancer, but its prevalence and risk association in the Brazilian population have not been determined. ... -
Prevalence of the TP53 p.R337H mutation in breast cancer patients in Brazil
(2014) [Artículo de periódico]Germline TP53 mutations predispose individuals to multiple cancers and are associated with Li-Fraumeni/Li-Fraumeni-Like Syndromes (LFS/LFL). The founder mutation TP53 p.R337H is detected in 0.3% of the general population ...