996 resultados para Maailma - kartat - 1500-luku
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La investigación se realizó con un universo de 220 pacientes, todos fueron niños prematuros menores de 1500 gramos nacidos entre el año 2011 al año 2013 y atendidos en la unidad de cuidados intensivos e intermedios neonatales del Hospital Nacional Especializado de Maternidad. El diagnóstico de la enfermedad se realizó principalmente basado en la necesidad de oxígeno suplementario por un mínimo de 28 días y según los criterios diagnósticos propuestos por el consenso del Instituto Nacional de la Salud de EE.UU (NICHD/NHLBI/ORD WORSHOP, 2000) (4) Se pudo evidenciar que los prematuros estudiados nacieron con mayor frecuencia a las 29 semanas de edad gestacional (calculadas por el método de Ballard modificado) y con un peso entre los 750 y los 1000 gramos. El tipo de displasia broncopulmonar más frecuentemente diagnosticado fue el de tipo leve y los factores de riesgo relacionados al desarrollo de la enfermedad fueron la presencia de infección materna al momento del parto y la infección posnatal, principalmente la infección asociada a la atención sanitaria (IAAS), la prematurez extrema y el extremado bajo peso al nacer; así como el uso prolongado de oxígeno por más de 55 días. El uso excesivo de líquidos endovenosos y la presencia de un conducto arterioso permeable ocurrieron con menos frecuencia.
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Mode of access: Internet.
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Lower levels of cytosine methylation have been found in the liver cell DNA from non-obese diabetic (NOD) mice under hyperglycemic conditions. Because the Fourier transform-infrared (FT-IR) profiles of dry DNA samples are differently affected by DNA base composition, single-stranded form and histone binding, it is expected that the methylation status in the DNA could also affect its FT-IR profile. The DNA FT-IR signatures obtained from the liver cell nuclei of hyperglycemic and normoglycemic NOD mice of the same age were compared. Dried DNA samples were examined in an IR microspectroscope equipped with an all-reflecting objective (ARO) and adequate software. Changes in DNA cytosine methylation levels induced by hyperglycemia in mouse liver cells produced changes in the respective DNA FT-IR profiles, revealing modifications to the vibrational intensities and frequencies of several chemical markers, including νas -CH3 stretching vibrations in the 5-methylcytosine methyl group. A smaller band area reflecting lower energy absorbed in the DNA was found in the hyperglycemic mice and assumed to be related to the lower levels of -CH3 groups. Other spectral differences were found at 1700-1500 cm(-1) and in the fingerprint region, and a slight change in the DNA conformation at the lower DNA methylation levels was suggested for the hyperglycemic mice. The changes that affect cytosine methylation levels certainly affect the DNA-protein interactions and, consequently, gene expression in liver cells from the hyperglycemic NOD mice.
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Universidade Estadual de Campinas . Faculdade de Educação Física
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A common side effect of radiotherapy used in the treatment of oral cancer is the occurrence of structural and physiological alterations of the salivary glands due to exposure to ionizing radiation, as demonstrated by conditions such as decreased salivary flow. The present study evaluated ultrastructural alterations in the parotid glands of rats receiving a fractionated dose (1,500-cGy) of radiation emitted by a Cesium-137 source and rats that were not subjected to ionizing radiation. After sacrifice, the parotid glands were removed and examined by transmission electron microscopy. Damage such as cytoplasmic vacuolization, dilatation of the endoplasmic reticulum and destruction of mitochondria, as well as damage to the cellular membrane of acinar cells, were observed. These findings lead to the conclusion that ionizing radiation promotes alterations in the glandular parenchyma, and that these alterations are directly related to the dose level of absorbed radiation. Certain phenomena that appear in the cytoplasm and nuclear material indicate that ionizing radiation causes acinar cell death (apoptosis).
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OBJETIVO: Estimar a prevalência e fatores associados à doença pulmonar obstrutiva crônica. MÉTODOS: Estudo transversal, de base populacional com 1.441 indivíduos de ambos os sexos e com 40 anos de idade ou mais no município de São Paulo, SP, entre 2008 e 2009. As informações foram coletadas por meio de entrevistas domiciliares e os participantes foram selecionados a partir de amostragem probabilística, estratificada por sexo e idade, e por conglomerados em dois estágios (setores censitários e domicílios). Foi realizada regressão múltipla de Poisson na análise ajustada. RESULTADOS: Dos entrevistados, 4,2% (IC95% 3,1;5,4) referiram doença pulmonar obstrutiva crônica. Após análise ajustada, identificaram-se os seguintes fatores independentemente associados ao agravo: número de cigarros fumados na vida (> 1.500/nenhum) RP = 3,85 (IC95%: 1,87;7,94), cansar-se com facilidade (sim/não) RP = 2,61 (IC95% 1,39;4,90), idade (60 a 69 anos/50 a 59 anos) RP = 3,27 (IC95% 1,01;11,24), idade (70 anos e mais/50 a 59 anos) RP = 4,29 (IC95% 1,30;14,29), problemas de saúde nos últimos 15 dias (sim/não) RP = 1,31 (IC95% 1,02;1,77), e atividade física no tempo livre (sim/não) RP = 0,57 (IC95% 0,26;0,97). CONCLUSÕES: A prevalência da doença pulmonar obstrutiva crônica é elevada e está associada ao uso do tabaco e idade acima de 60 anos. Os problemas de saúde freqüentes e redução da atividade física no tempo livre podem ser considerados conseqüências dessa doença.
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We investigate synchronization in a Kuramoto-like model with nearest neighbor coupling. Upon analyzing the behavior of individual oscillators at the onset of complete synchronization, we show that the time interval between bursts in the time dependence of the frequencies of the oscillators exhibits universal scaling and blows up at the critical coupling strength. We also bring out a key mechanism that leads to phase locking. Finally, we deduce forms for the phases and frequencies at the onset of complete synchronization.
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Tamarindus indica has been used in folk medicine as an antidiabetic, a digestive aid, and a carminative, among other uses. Currently, there is no information in the toxicology literature concerning the safety of T. indica extract. We evaluated the clastogenic and/or genotoxic potential of fruit pulp extract of this plant in vivo in peripheral blood and liver cells of Wistar rats, using the comet assay, and in bone marrow cells of Swiss mice, using the micronucleus test. The extract was administered by gavage at doses of 1000, 1500 and 2000 mg/kg body weight. Peripheral blood and liver cells from Wistar rats were collected 24 h after treatment, for the comet assay. The micronucleus test was carried out in bone marrow cells from Swiss mice collected 24 h after treatment. The extract made with T. indica was devoid of clastogenic and genotoxic activities in the cells of the rodents, when administered orally at these three acute doses.
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Only a few decades after 1492, when Christopher Columbus arrived on a Caribbean island and Pedro Alvares Cabral claimed Brazil for Portugal in 1500, a German mercenary gave the first description of stingless bees in 1557. He got to know them when he was imprisoned for months by an anthropophagous tribe in the coastal region of Santos, today in the State of Sao Paulo. This rather short but nevertheless extremely exact record on stingless bees is hidden in the first book on Brazil. Three species and important aspects of their life history were treated. This early description has been completely overlooked by bee scientists until now. My note intends to close this evident gap.
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Ion channels are pores formed by proteins and responsible for carrying ion fluxes through cellular membranes. The ion channels can assume conformational states thereby controlling ion flow. Physically, the conformational transitions from one state to another are associated with energy barriers between them and are dependent on stimulus, such as, electrical field, ligands, second messengers, etc. Several models have been proposed to describe the kinetics of ion channels. The classical Markovian model assumes that a future transition is independent of the time that the ion channel stayed in a previous state. Others models as the fractal and the chaotic assume that the rate of transitions between the states depend on the time that the ionic channel stayed in a previous state. For the calcium activated potassium channels of Leydig cells the R/S Hurst analysis has indicated that the channels are long-term correlated with a Hurst coefficient H around 0.7, showing a persistent memory in this kinetic. Here, we applied the R/S analysis to the opening and closing dwell time series obtained from simulated data from a chaotic model proposed by L. Liebovitch and T. Toth [J. Theor. Biol. 148, 243 (1991)] and we show that this chaotic model or any model that treats the set of channel openings and closings as independent events is inadequate to describe the long-term correlation (memory) already described for the experimental data. (C) 2008 American Institute of Physics.
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Context. Tight binaries discovered in young, nearby associations are ideal targets for providing dynamical mass measurements to test the physics of evolutionary models at young ages and very low masses. Aims. We report the binarity of TWA22 for the first time. We aim at monitoring the orbit of this young and tight system to determine its total dynamical mass using an accurate distance determination. We also intend to characterize the physical properties (luminosity, effective temperature, and surface gravity) of each component based on near-infrared photometric and spectroscopic observations. Methods. We used the adaptive-optics assisted imager NACO to resolve the components, to monitor the complete orbit and to obtain the relative near-infrared photometry of TWA22 AB. The adaptive-optics assisted integral field spectrometer SINFONI was also used to obtain medium-resolution (R(lambda) = 1500-2000) spectra in JHK bands. Comparison with empirical and synthetic librairies were necessary for deriving the spectral type, the effective temperature, and the surface gravity for each component of the system. Results. Based on an accurate trigonometric distance (17.5 +/- 0.2 pc) determination, we infer a total dynamical mass of 220 +/- 21 M(Jup) for the system. From the complete set of spectra, we find an effective temperature T(eff) = 2900(-200)(+200) K for TWA22A and T(eff) = 2900(-100)(+200) for TWA22 B and surface gravities between 4.0 and 5.5 dex. From our photometry and an M6 +/- 1 spectral type for both components, we find luminosities of log(L/L(circle dot)) = -2.11 +/- 0.13 dex and log(L/L(circle dot)) = -2.30 +/- 0.16 dex for TWA22 A and B, respectively. By comparing these parameters with evolutionary models, we question the age and the multiplicity of this system. We also discuss a possible underestimation of the mass predicted by evolutionary models for young stars close to the substellar boundary.
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In this paper, we initially present an algorithm for automatic composition of melodies using chaotic dynamical systems. Afterward, we characterize chaotic music in a comprehensive way as comprising three perspectives: musical discrimination, dynamical influence on musical features, and musical perception. With respect to the first perspective, the coherence between generated chaotic melodies (continuous as well as discrete chaotic melodies) and a set of classical reference melodies is characterized by statistical descriptors and melodic measures. The significant differences among the three types of melodies are determined by discriminant analysis. Regarding the second perspective, the influence of dynamical features of chaotic attractors, e.g., Lyapunov exponent, Hurst coefficient, and correlation dimension, on melodic features is determined by canonical correlation analysis. The last perspective is related to perception of originality, complexity, and degree of melodiousness (Euler's gradus suavitatis) of chaotic and classical melodies by nonparametric statistical tests. (c) 2010 American Institute of Physics. [doi: 10.1063/1.3487516]