27 resultados para SO(2)
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It was earlier shown that an SO(9,1) θα spinor variable can be constructed from RNS matter and ghost fields. θα has a bosonic world-sheet super-partner λα which plays the role of a twistor variable, satisfying λΓμ λ = ∂xμ + iθΓμ ∂θ. For Type IIA superstrings, the left-moving [θL α, λL α] and right-moving [θRα, λRα] can be combined into 32-component SO(10,1) spinors [θA, λA]. This suggests that λAΓAB 11 λB = 2λL αλRα can be interpreted as momentum in the eleventh direction. Evidence for this interpretation comes from the zero-momentum vertex operators of the Type IIA superstring and from consideration of DD-branes. As in the work of Bars, one finds an SO(10,2) structure for the Type IIA superstring and an SO(9, 1) × SO(2, 1) structure for the Type IIB superstring. © 1997 Elsevier Science B.V.
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Pós-graduação em Zootecnia - FMVZ
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We show that an anisotropic nonquadratic potential, for which a path integral treatment has been recently discussed in the literature, possesses the SO(2, 1) ⊗SO(2, 1) ⊗SO(2, 1) dynamical symmetry, and construct its Green function algebraically. A particular case which generates new eigenvalues and eigenfunctions is also discussed. © 1990.
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We show that by using second-order differential operators as a realization of the so(2,1) Lie algebra, we can extend the class of quasi-exactly-solvable potentials with dynamical symmetries. As an example, we dynamically generate a potential of tenth power, which has been treated in the literature using other approaches, and discuss its relation with other potentials of lowest orders. The question of solvability is also studied. © 1991 The American Physical Society.
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Pain is a subjective condition and, thus, difficult to measure. The best tools to assess pain are the pain evaluation questionnaires, which provide either diagnostic, pain evolution or pain intensity information. To provide information which could help differentiate between nociceptive pain and neuropathic pain is one of the most important functions of these questionnaires. The questionnaires can measure pain intensity, quality of life, or sleep quality. Quality of life and sleep are two really important characteristics to assess the pain impact on patients' life. Pain intensity assessing questionnaires combine physical evaluations with questions, providing information either from the patient sensations or clinical assessment of pain manifestations as well as the underlying biological mechanisms (such as hyperalgesia or allodynia). For example, the Pain Detect questionnaire has two parts: the patient form (intuitive, with pictures and easy understandable) and the physician form. Thus, in this questionnaire, subjective information is provided by the patient and the objective one is provided by the physician. Other pain intensity questionnaires are NPSI, DN4, LANSS or StEP. Quality of life questionnaires are versatile (can be used in different pathologies). These questionnaires include functional self-evaluation questions, and other ones associated to physical and mental health. Two of such quality of life questionnaires are SF-36 and NHP. Sleep evaluation questionnaires include quantitative features such as the number of sleep interruptions, sleep latency or sleep duration as well as qualitative characteristics such as rest sensation, mood and dreams. One of the most used sleep evaluation questionnaires is PSQI, which includes patient questions and bed-partner questions, providing information from two points of view.
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Using an algebraic technique related to the SO (2, 1) group we construct the Green function for the potential ar2 + b(r sin θ)-2 + c(r cos θ)-2 + dr2 sin2θ + er2 cos2θ. The energy spectrum and the normalized wave functions are also obtained. © 1990.
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This work evaluated the rainwater chemical composition and the annual atmospheric deposition in Sorocaba, (Sao Paulo State), Brazil. One sampling ˜ point was chosen and forty samples were collected between January and December 2006. The analyses were performed for pH, electrical conductivity, sodium, calcium, potassium, magnesium, sulphate, nitrate, phosphate, alkalinity and chloride. The rainwater pH varied from 5.20 to 6.40, being Ca2+ the main ion responsible for controlling the rainwater pH. The ionic concentration decreases in the following order: Ca2+>Na+> K+>Mg2+ for cations and SO2− 4 >HCO− 3 >NO− 3 >Cl−>PO3− 4 for anions. The annual atmospheric deposition appears to be controlled by the following sources: mining activities and cement factories (Ca2+ and HCO− 3 ), agricultural activities (K+, NO− 3 and PO3− 4 ), soil dust (Na+, Mg2+ and HCO− 3 ) and fossil fuel burning (SO2− 4 )
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Rate coefficients for radiative association of SO, SO+, and S-2 are estimated. For temperatures ranging from 300 to 14,000 K, the direct radiative association rate coefficients are found to vary with temperature from 1.73 x 10(-19) to 7.29 x 10(-19) cm(3) s(-1) and from 1.49 x 10(-21) to 3.70 x 10(-19) cm(3) s(-1) for S-2 and SO, respectively. The rate coefficients for formation through the inverse predissociation for S-2 are found to vary from 3.59 x 10(-18) to 1.44 x 10(-20) cm(3) s(-1). For SO+, the direct rate coefficient varies rapidly with temperature from 3.62 x 10(-27) cm(3) s(-1) at 2000 K to 2.34 x 10(-20) cm(3) s(-1) at 14,000 K. The direct radiative association rate coefficients increase with the increase in temperature, but the inverse predissociation rate coefficients decrease with the increase in temperature.
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The Archean (3.45-2.70Ga) rocks of the São José do Campestre Massif (SJCM) in the Borborema Province (NE Brazil) make up a small area (~6000km2) and are composed of granitoids and metasupracrustal rocks that define a complex magmatic and deformational history. The massif provides the opportunity to study mantle- and crustal-derived magmas generated since the Palaeoarchean. The orthogneisses of the SJCM are composed of: (1) tonalite to granodiorite with diorite enclaves (Bom Jesus gneiss, 3412±8Ma; TDM Nd model ages from 4.1 to 3.5Ga and negative epsilon Nd values); (2) biotite and ferroan-diopside monzogranite (Presidente Juscelino complex, 3356±21Ma and 3251±44Ma; TDM model ages range from 4.1 to 3.4Ga and epsilon Nd values that are slightly positive to negative); (3) hornblende tonalite to granodiorite (Brejinho complex, 3333±77Ma and 3187±8Ma; dominantly positive epsilon Nd values and TDM ages from 3.6 to 3.2Ga); (4) biotite monzogranite (São Pedro do Potengi gneiss, 3120±22Ma; TDM =3.5Ga; negative epsilon Nd value); (5) ferroan-diopside-grossular anorthosite and metagabbro (Senador Elói de Souza complex, 3033±3Ma); and (6) quartz diorite to syenogranite (São José do Campestre complex; 2685±9Ma and 2655±4Ma; negative epsilon Nd values and TDM ages from 3.9 to 3.3Ga). The orthogneisses are subalkaline to faintly alkaline, magnesian to ferroan, M- and I-type granitoids that follow either the K-enrichment or the trondhjemite trends. Each group has a subset with REE characteristics similar to Archean TTG and another that is analogous to Phanerozoic granitoids. They have negative Ta-Nb and Ti anomalies and have trace element contents of granitoids from subduction zones. Geochemical and Nd isotope data suggest that subducted oceanic crust and a depleted and metasomatised mantle wedge both acted as the magma sources. We propose a convergent tectonic model in which hybridisation of the upper mantle occurs through interactions with adakitic or trondhjemitic melts and recycling of earlier crust. The results imply that both the subducted oceanic crust and the mantle wedge played major roles in continent formation throughout successive episodes of arc accretion in Palaeo- and Mesoarchean times. The Archean rocks of the SJCM shares some similarities with the Pilbara, Kaapvaal, West African, and São Francisco cratons. However, the most reliable comparisons with the SJCM are with the neighbouring basement of the Nigeria and Cameroon shields. © 2012 Elsevier B.V.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Pós-graduação em Geografia - IGCE
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)