1,290 research outputs found
Clumping factors of HII, HeII and HeIII
Estimating the intergalactic medium ionization level of a region needs proper
treatment of the reionization process for a large representative volume of the
universe. The clumping factor, a parameter which accounts for the effect of
recombinations in unresolved, small-scale structures, aids in achieving the
required accuracy for the reionization history even in simulations with low
spatial resolution.
In this paper, we study for the first time the redshift evolution of clumping
factors of different ionized species of H and He in a small but very high
resolution simulation of the reionization process. We investigate the
dependence of the value and redshift evolution of clumping factors on their
definition, the ionization level of the gas, the grid resolution, box size and
mean dimensionless density of the simulations.Comment: 12 pages, 10 figures, 1 table. Accepted by MNRA
Determining the Gamma-Ray Burst Rate as a Function of Redshift
We exploit the 14 gamma-ray bursts (GRBs) with known redshifts z and the 7
GRBs for which there are constraints on z to determine the GRB rate R_{GRB}(z),
using a method based on Bayesian inference. We find that, despite the
qualitative differences between the observed GRB rate and estimates of the SFR
in the universe, current data are consistent with R_{GRB}(z) being proportional
to the SFR.Comment: To appear in Procs. of Gamma-Ray Bursts in the Afterglow Era: 2nd
Workshop, 3 pages, 3 figures, LaTe
Determining the GRB (Redshift, Luminosity)-Distribution Using Burst Variability
We use the possible Cepheid-like luminosity estimator for the long-duration gamma-ray bursts (GRBs) developed by Reichart et al. (2000) to estimate the intrinsic luminosity, and thus the redshift, of 907 long-duration GRBs from the BATSE 4B catalog. We describe a method based on Bayesian inference which allows us to infer the intrinsic GRB burst rate as a function of redshift for bursts with estimated intrinsic luminosities and redshifts. We apply this method to the above sample of long-duration GRBs, and present some preliminary results
Análise molecular de isolados do gênero leishmania e clínica de pacientes portadores de leishmaniose tegumentar americana atendidos no Hospital Universitário de Brasília
Dissertação (mestrado)—Universidade de Brasília, Faculdade de Ciências da Saúde, Programa de Pós-Graduação em Ciências da Saúde, 2013.A Leishmaniose Tegumentar Americana é um grave problema de saúde pública no Brasil e em vários países do mundo. As diferentes manifestações clínicas podem variar desde uma lesão localizada até multiplas lesões distribuidas por todo o corpo. Fatores inerentes às diferentes espécies do parasita contribuem para a diversidade clínica e para a patogênese da doença. O objetivo deste trabalho foi estudar através de metodologias moleculares isolados de Leishmania e relacionar com os aspectos clínicos dos pacientes fontes. A identificação foi realizada através da PCR do gene miniexon, PCR-RFLP e sequenciamento da região ITS1 do rDNA. Foram analisados 38 isolados provenientes de 36 pacientes e foram identificados: 22 L. (V.)
braziliensis, 3 L. (V.) panamensis, 1 L. (V.) guyanensis, 1 L. (V.) utingensis, 2 L. (V.)
spp, 8 L. (L.) amazonensis e 1 L. (L.) infantum. Os pacientes que predominaram eram do sexo masculino em idade reprodutiva com lesões nos membros superiores
e inferiores. Os pacientes infectados pelo subgênero Viannia desenvolveram em
81% dos casos leishmaniose cutânea. Apenas pacientes infectados por L. (V.)
braziliensis desenvolveram leishmaniose mucosa. Um paciente infectado por L. (V.)
braziliensis e co-infectado por HIV desenvolveu a Síndrome de Reconstituição
Imune. Entre os oito pacientes infectados pela espécie L. (L.) amazonensis, seis apresentaram leishmaniose cutânea, um apresentou a forma cutânea disseminada e um apresentou leishmaniose cutânea difusa. O único paciente infectado por L. (L.) infantum apresentou três lesões cutâneas ulceradas. A técnica RAPD permitiu comparar fingerprints de isolados de um mesmo paciente a fim de analisar as modificações ao longo de sucessivas recidivas. Através desta técnica foi possível caracterizar duas cepas de L. (L.) amazonensis como idênticas, isoladas de dois pacientes com formas clínicas graves e raras (LCD e LD). Neste estudo relata-se pela primeira vez como agentes etiológicos da leishmaniose tegumentar no Brasil as espécies: L. (V.) utingensis e L. (L) infantum. A L. (V.) utingensis é descrita pela
primeira vez infectando humanos e a L. (L) infantum desencadeando leishmaniose
cutânea. Devido ao amplo espectro clínico causado pelas espécies de Leishmania, o
diagnóstico molecular pode ser útil para o prognóstico clínico rotineiro da leishmaniose bem como para compreensão da ocorrência e comportamento de cada espécie. ______________________________________________________________________________ ABSTRACTLeishmaniasis is a serious public health problem in Brazil and in several countries worldwide. The different clinical manifestations may vary since a localized lesion until multiple lesions distributed throughout the body. Factors inherent to the different species of the parasite contribute to the clinical diversity and pathogenesis of the disease. The aim of this work was to study through molecular methodologies of Leishmania's isolates and relate them with clinical aspects of the patient's sources. The identification was performed by PCR miniexon gene, PCR-RFLP and sequencing of ITS1 from rDNA gene. In this study 38 isolates from 36 patients were analyzed and were identified: 22 L. (V.) braziliensis, 3 L. (V.) panamensis, 1 L. (V.)
guyanensis, 1 L. (V.) utingensis, 2 L. (V.) spp, 8 L. (L.) amazonensis and 1 L. (L.) infantum. Patients were males in reproductive age with lesions in upper and lower limbs. The patients infected by the Viannia subgenus have developed cutaneous leishmaniasis, in 81% cases. Only patients infected by L. (V.) braziliensis developed ucosal leishmaniasis. One patient infected by L. (V.) braziliensis and co-infected with HIV developed immune reconstitution syndrome. Among the eight patients infected by the L. (L.) amazonensis, six have developed cutaneous leishmaniasis, one presented disseminated cutaneous form and the other had diffuse cutaneous leishmaniasis. The single patient infected by L. (L.) infantum has showed an atypical form of cutaneous leishmaniasis. The RAPD technique allowed us to compare
fingerprints of isolates from the same patient, in order to analyze changes over successive recurrences. By using this technique, it was possible to characterize two strains of L. (L.) amazonensis as identical, these was isolated from two patients with severe clinical and rare forms (LCD and LD). The present study reports, for the first time as etiologic agents of cutaneous leishmaniasis in Brazil, the following species: L. (V.) utingensis and L. (L) infantum. L. (V.) utingensis is first described infecting humans and L. (L) infantum unleashing cutaneous leishmaniasis. Due to the wide clinical spectrum caused by Leishmania species, the molecular diagnosis can be useful for routine clinical prognosis of leishmaniasis as well as for understanding the occurrence and behavior of each species
Atmospheric levels of BPA associated with particulate matter in an urban environment
Bisphenol A (BPA) is an Endocrine disruptor compound (EDC), capable of interfering with hormone related pathways and cause adverse effects, for example, in the reproductive system in wildlife and humans. As it has multiple applications and uses, mainly in the manufacturing of plastic and resin products, increasing amounts are being released into the environment with resulting enhanced exposure pathways. Since negative effects have been demonstrated even at low doses, it has been increasingly studied. However, these investigations have focused on BPA leaching from food cans, drinks and other consumer products as the oral exposure route is believed to be the most important. Consequently, the potential hazards of dermal or inhalation exposure resulting from the current levels of BPA in the atmosphere are poorly understand. Of the few studies reporting BPA occurrence in air, none of these were carried out in South American countries. Thus, the aim the present investigation was to assess BPA current levels in particulate matter in an urban environment (Córdoba, Argentina) and to analyze its spatial-temporal trends and the influence of meteorological parameters using a medium volume air sampler. Our results suggested a spatial trend that decreased according to the distance to emission sources in the order: Industrial area > City Centre > University campus, whose levels were comparable to other urban cities and with the temporal trend showing a higher prevalence of the compound in the colder months. Wind speed (WS), temperature (T), atmospheric pressure (AP) and relative humidity (RL) were the most influenced variables. However daily values are unpredictable and depend mainly on the emission sources and punctual events that release BPA into the atmosphere. No risk factor could be quantified since there is no reference value for this exposure route; Nevertheless, this study represents the first approach and provides data about this emergent pollutant in and Argentinean city, thus contributing to global BPA studies.Fil: Graziani, Natalia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Carreras, Hebe Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Wannaz, Eduardo Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; Argentin
Determining the Gamma-Ray Burst Rate as a Function of Redshift
We exploit the 14 gamma-ray bursts (GRBs) with known redshifts z and the 7 GRBs for which there are constraints on z to determine the GRB rate R_(GRB)(z), using a method based on Bayesian inference. We find that, despite the qualitative differences between the observed GRB rate and estimates of the SFR in the universe, current data are consistent with R_(GRB)(z) being proportional to the SFR
Ultrassonografia transcraniana na doença de Parkinson
Transcranial sonography has become a useful tool in the differential diagnosis of parkinsonian syndromes. This is a non-invasive, low cost procedure. The main finding on transcranial sonography in patients with idiopathic Parkinson's disease is an increased echogenicity of the mesencephalic substantia nigra region. This hyperechogenicity is present in more than 90% of cases, and reflects a dysfunction in the dopaminergic nigrostriatal pathway. This study discussed how the hyperechogenicity of the substantia nigra may facilitate the differential diagnosis of parkinsonian syndromes.A ultrassonografia transcraniana tem se tornado ferramenta útil no diagnóstico diferencial das síndromes parkinsonianas. Trata-se de um método não invasivo e de baixo custo. O principal achado da ultrassonografia transcraniana em pacientes com doença de Parkinson idiopática é o aumento da ecogenicidade, ou hiperecogenicidade, na região da substância negra mesencefálica, presente em mais de 90% dos casos, o que reflete disfunção da via dopaminérgica nigroestriatal. O presente trabalho abordou como a hiperecogenicidade da substância negra pode auxiliar no diagnóstico diferencial das síndromes parkinsonianas.Universidade de São Paulo Division of Clinical NeurosurgeryHospital Israelita Albert EinsteinUniversidade Federal de São Paulo (UNIFESP) Department of Neurology and NeurosurgeryHospital Israelita Albert Einstein Instituto do CérebroUNIFESP, Department of Neurology and NeurosurgerySciEL
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