Phase Fluctuations and Vortex Lattice Melting in Triplet Quasi-One-Dimensional Superconductors at High Magnetic Fields

Assuming that the order parameter corresponds to an equal spin triplet pairing symmetry state, we calculate the effect of phase fluctuations in quasi-one-dimensional superconductors at high magnetic fields applied along the y (b') axis. We show that phase fluctuations can destroy the theoretically predicted triplet reentrant superconducting state, and that they are responsible for melting the magnetic field induced Josephson vortex lattice above a magnetic field dependent melting temperature Tm.Comment: 4 pages (double column), 1 eps figur

Counting States: A Combinatorial Analysis of SQM Fragmentation

The Strange Quark matter (SQM) hypothesis states that at extreme pressure and density conditions a new ground state of matter would arise, in which half of the \textit{down} quarks become strange quarks. If true, it would mean that at least the core of neutron stars is made of SQM. In this hypothesis, SQM would be released in the inter-stellar medium when two of these objects merge. It is estimated that $10^{-2} M\odot$ of SQM would be released this way. This matter will undergo a sequence of processes that should result in a fraction of the released SQM becoming heavy nuclei through \textit{r-process}. In this work we are interested in characterizing the fragmentation of SQM, with the novelty of keeping track of the \textit{quark configuration} of the fragmented matter. This is accomplished by developing a methodology to estimate the energy of each fragment as the sum of its \textit{constituent quarks}, the Coulomb interaction among the quarks and fragments' momenta. The determination of the fragmentation output is crucial to fully characterize the subsequent nucleosynthesis.Comment: 4 pages, 2 figures, 2 table

Modified kraske procedure with mid-sacrectomy and coccygectomy for en bloc excision of sacral giant cell tumors.

Sacral giant cell tumors are rare neoplasms, histologically benign but potentially very aggressive due to the difficulty in achieving a complete resection, their high recurrence rate, and metastization capability. Although many treatment options have been proposed, en bloc excision with tumor-free margins seems to be the most effective, being associated with long term tumor control, improved outcome, and potential cure. An exemplifying case of a 29-year-old female with progressive complaints of pain and paresthesias in the sacral and perianal regions, constipation, and weight loss for 6 months is presented. The surgical technique for en bloc excision of a large sacral giant cell tumor through a modified Kraske procedure with mid-sacrectomy and coccygectomy is described. Complete resection with wide tumor-free margins was achieved. At 5 years of follow-up the patient is neurologically intact, without evidence of local recurrence on imaging studies. A multidisciplinary surgical procedure is mandatory to completely remove sacral tumors. In the particular case of giant cell tumors, it allows minimizing local recurrence preserving neurovascular function, through a single dorsal and definitive approach

AGREGADOS TUBULARES DE RETÍCULO ENDOPLASMÁTICO LISO EM OVÓCITOS HUMANOS E SUA INFLUÊNCIA NAS TAXAS DE FERTILIZAÇÃO E GRAVIDEZ

O impacto da presença de anomalias morfológicas ovocitárias na fertilização e taxas de gravidez é um tema controverso na literatura. A presença de agregados tubulares de retículo endoplasmático liso (AT-REL) foi associada a taxas de gravidez mais baixas e a maior incidência de complicações obstétricas. A estrutura ultramiscroscópica destes AT-REL não está descrita. Este trabalho teve como objectivos: a) determinar a influência da presença de AT-REL nas taxas de fertilização e gravidez; b) descrever a ultrastrutura dos AT-REL de ovócitos humanos maduro

A phenomenological model of the superconducting state of the Bechgaard salts

We present a group theoretical analysis of the superconducting state of the Bechgaard salts, e.g., (TMTSF)_2PF_6 or (TMTSF)_2ClO_6. We show that there are eight symmetry distinct superconducting states. Of these only the (fully gapped, even frequency, p-wave, triplet) 'polar state' is consistent with the full range of the experiments on the Bechgaard salts. The gap of the polar state is d(k) (psi_uk,0,0), where psi_uk may be any odd parity function that is translationally invariant.Comment: 4 pages, no figure

Produção animal de base familiar no semi-árido sergipano.

bitstream/CPATC/19778/1/f_16_2007.pd

Caracterização geoquímica e isotópica de depósitos sedimentares vulcanogénicos do Ordovícico Inferior do Sinclinal de Moncorvo, Nordeste de Portugal

Os ambientes geodinâmicos extensionais na Zona Centro Ibérica, durante o Ordovícico Inferior, favoreceram a ocorrência de episódios vulcânicos. No sinclinal de Moncorvo há evidências desses episódios, preservados sob a forma de depósitos sedimentares vulcanogénicos intercalados em metassedimentos da Formação Marão. Estes depósitos são essencialmente constituídos por quartzo, mas também contêm moscovite, fosfatos da série lazulite - scorzalite, zircão, monazite, raros opacos e turmalina. Embora os depósitos se apresentem recristalizados e com foliação metamórfica penetrativa, a sua granulometria fina, espessura (< 40 cm) e mineralogia sugerem que corresponderiam a depósitos de cinzas distais, com afinidade riodacítica, envolvendo a mistura com materiais detríticos. A datação U-Pb, obtida por ID-TIMS em zircão, indica uma idade preliminar de formação de 484.5 ± 3.0 Ma. Os elevados teores em alguns elementos incompatíveis, a razão CaO/Na2O de 0.33 a 1.77, perfis de REE com (La/Lu)N = 3.37 a 7.96 e discreta anomalia negativa de Eu, valores de (87Sr/86Sr)i t variáveis entre 0.71156 e 0.71304 e -10.8 e -10.0, respectivamente, indicam que os materiais vulcânicos teriam resultado da fusão parcial de metassedimentos semelhantes aos do Grupo do Douro e equivalentes do n orte da Zona Centro Ibérica. Porém, o envolvimento de processos sedimentares terá tido uma influência significativa na geoquímica elementar e isotópica destas rochas.The extensional geodynamic conditions in the Central Iberian Zone, during Lower Ordovician, were favorable to the occurrence of volcanic episodes. At the syncline of Moncorvo there are evidences of those episodes, which occur in the form of volcanogenic sedimentary deposits interbedded in the metasediments of Marão Formation. These deposits are mainly composed of quartz, but also contain muscovite, phosphates of the lazulite-scorzalite series, zircon, monazite, rare opaques and tourmaline. Despite the recrystallization and metamorphic foliation overprint, the fine -grained texture, the thickness (< 40 cm) and mineralogy of the deposits suggest that they correspond to distal ash -fall layers, with rhyodacitic to dacitic affinity, involving mixing with detrital materials. The U-Pb zircon dating, obtained by ID-TIMS, indicates a preliminary formation age of 484.5 ± 3.0 Ma. The high contents of some incompatible elements, the CaO/Na2O ratio between 0.33 and 1.77, the REE pattern with (La / Lu)N = 3.37 to 7.96 and slight negative Eu anomaly,(87Sr/86Sr)i and Ndt values variable between 0.71156 and 0.71304 and -10.8 and -10.0, respectively, indicate that the volcanogenic materials were derived from partial melting of metasediments similar to those of Douro Group and equivalents from northern Central Iberian Zone. However, the involvement of sedimentary processes may have had significant influence on elemental and isotopic geochemistry of these rocks

Contribution of residential wood combustion to PM10 levels in Portugal

Wood is commonly used in residential combustion for heating purposes; however, it can be a major source of air pollutants, namely fine particles, volatile organic compounds and carbon monoxide. Since 2004, the PM10 daily limit value has been surpassed in Portugal, and the European Commission has stated that plans and programs must be designed in order to reduce these levels. In Portugal, 18% of PM10 emissions are due to residential wood combustion, which may deeply impact the PM10 levels in the atmosphere. The main aim of this study is to investigate the impact of residential wood combustion on the air quality in Portugal. The air quality modelling system MM5/CHIMERE was applied over Portugal for a winter month, for the following three scenarios: the reference scenario, considering the actual emissions of PM10; scenario 1, where residential wood combustion emissions are not considered; and scenario 2, which takes into account a complete conversion from traditional fireplaces to certified appliances (with a 90% reduction in PM emissions). The residential wood combustion contribution to PM10 air quality concentration values during January 2007 ranges from 0 to 14 μg m−3, with a mean contribution of 10 μg m−3 in the Lisboa area and 6 μg m−3 in the Porto region. Concerning the legislated values, the area where the daily average limit value (50 μg m−3) is exceeded decreases by 46% in the simulation when residential combustion is not considered. The modelling results for scenario 2 are not significantly different from those for scenario 1. In summary, the regulation of the residential wood combustion sector is as an effective way to reduce the PM10 levels in the atmosphere as regards air quality plans and programs

Instability of three dimensional conformally dressed black hole

The three dimensional black hole solution of Einstein equations with negative cosmological constant coupled to a conformal scalar field is proved to be unstable against linear circularly symmetric perturbations.Comment: 5 pages, REVTe