12 research outputs found
Preliminary conceptual model of the Cerro Blanco caldera-hosted geothermal system (Southern Puna, Argentina): Inferences from geochemical investigations.
The Cerro Blanco Caldera (CBC) is the youngest collapse caldera system in the Southern Central Andes (Southern
Puna, Argentina). The CBC is subsiding with at an average velocity of 0.87 cm/year and hosts an active geothermal
system. A geochemical characterization of emitted fluids was carried out based on the chemical and
isotopic compositions of fumaroles, and thermal and cold springs discharged in this volcanic area with the aim of
constructing the first hydrogeochemical conceptual model and preliminary estimate the geothermal potential.
The main hydrothermal reservoir, likely hosted within the pre-caldera basement rocks, has a Na+-Clˉ(HCO3)ˉ
composition with estimated temperatures ≥135 °C. The unconsolidated, fine-grained Cerro Blanco ignimbrite
likely acts as the cap-rock of the hydrothermal system. The presence of phreatic eruption breccias in the surrounding
area of the geothermal fumaroles supports the effectiveness of the pyroclastic deposit as sealing rocks.
The isotopic data of water (δ18O and δD) indicate a meteoric recharge of the hydrothermal reservoir, suggesting
as recharge areas the sectors surrounding the CBC, mainly towards the W and NW where large outcrops of the
pre-caldera basement exist. A fault-controlled hydraulic connection between the hot springs and the hydrothermal
reservoir is proposed for the Los Hornitos area. The fumaroles show the typical compositional features of
hydrothermal fluids, being dominated by water vapor with significant concentrations of H2S, CH4 and H2.
Considering the high geothermal gradient of this area (∼104 °C/km) and the relatively high fraction of mantle
He (∼39%) calculated on the basis of the measured R/Ra values, the hydrothermal aquifer likely receives inputs
of magmatic fluids from the degassing magma chamber. The preliminary geothermal potential at CBC was
evaluated with the Volume Method, calculating up to E = 11.4*1018 J. Both the scarce presence of superficial
thermal manifestations and the occurrence of an efficient cap-rock likely contribute to minimize the loss of
thermal energy from the reservoir. The results here presented constitute the necessary base of knowledge for
further accurate assessment of the geothermal potential and ultimately the implementation of the geothermal
resource as a viable energy alternative for small localities or mining facilities isolated from the National
Interconnected System due to their remote localization.Published1022136A. Geochimica per l'ambiente e geologia medicaJCR Journa
Efeitos hemodinâmicos da anestesia em plano profundo com infusão intravenosa contÃnua de propofol ou propofol associado à lidocaÃna em cães
Comprometimento organizacional e qualidade de vida no trabalho para pessoas com e sem deficiência
Pulsating flow dynamics of sustained, forced pyroclastic density currents: insights from a facies analysis of the Campo de la Piedra Pómez ignimbrite, southern Puna, Argentina
The Quaternary Campo de la Piedra Pomez ignimbrite (CPPI) is a superbly exposed, partially indurated, rhyolitic ignimbrite emplaced on the southern Puna of Argentina. It is characterized by a variety of facies that record in unprecedented detail the flow dynamics of the parent pyroclastic density currents (PDCs). Detailed facies analysis and internal architecture defined using a sequential stratigraphy approach reveal that CPPI was formed by sustained PDCs, generated from a low fountain eruptive style (boiling over). The PDCs had overall flow conditions characterized by high particle concentration and limited capability to surmount topographic obstacles. The mobility of the PDCs was largely controlled by high pore pressure and the continuous supply at the source (sustained forced convection-dominated PDCs). The successive forestepping-backstepping stacking patterns identified in the CPPI reflect a marked unsteadiness of its parent PDCs due to a pulsating discharge rate at the source. The lateral facies variations in the CPPI record the non-uniform character of its parent PDCs as they flowed outward from the base of the collapsing fountain. Proximal-medial areas characterized by steady aggradation rates pass through to distal braided thalwegs with highly variable aggradation rates, to frontal edges characterized by the step aggradations of secondary decoupled pumice-rich lobes. Collectively, the facies variations in the CPPI record the complex dynamics of sustained PDCs that include pulsating discharge rate at the source, progressive modification of the original topography, and lateral flow transformations
Safety of yellow fever vaccination in pregnancy: findings from a cohort of active duty US military women
Vivências de trabalhadores com deficiência: uma análise à luz da Psicodinâmica do Trabalho
Relações entre significado do trabalho e percepção de suporte para pessoas com deficiência em organizações brasileiras
Análise quantitativa das fibras mielÃnicas dos nervos larÃngeos em humanos de acordo com a idade Quantitative analysis of myelinic fibers in human laryngeal nerves according to age
INTRODUÇÃO E OBJETIVO: Realizar análise morfométrica das fibras mielÃnicas dos nervos larÃngeos com a finalidade de verificar modificações quantitativas decorrentes do processo de envelhecimento. FORMA DE ESTUDO: ClÃnico e experimental. Material e Método: Foi coletado fragmento de 1cm dos nervos larÃngeos superiores e nervos larÃngeos recorrentes de 12 cadáveres do sexo masculino. A amostra foi dividida em dois grupos: idade inferior a 60 anos (Adulto) e idade igual ou superior a 60 anos (Idoso). O material foi avaliado em microscópio de luz acoplado a sistema analisador de imagem. RESULTADOS: O número total de fibras mielÃnicas do nervo larÃngeo superior foi semelhante nos dois grupos etários, mas com tendência para o maior número de fibras de 1µm no grupo adulto (p=0,0744). O grupo adulto apresentou maior número total de fibras mielÃnicas no nervo larÃngeo recorrente (p=0,0006), e esta diferença ocorreu nas fibras com diâmetros de 1-3µm (p<0,007). O grupo adulto apresentou maior número total de fibras mielÃnicas nos nervos larÃngeos (soma das fibras dos nervos larÃngeos superiores e dos nervos larÃngeos recorrentes) que o grupo idoso (p<0,0091). CONCLUSÃO: O número total de fibras mielÃnicas dos nervos larÃngeos é maior no grupo com idade inferior a 60 anos.<br>INTRODUCTION AND AIM: To carry out a morphometric analysis of myelinic fibers in laryngeal nerves aiming to identify quantitative changes as a result of aging. Study design: Clinical and experimental. MATERIAL AND METHOD: A 1cm fragment was collected from the superior laryngeal nerves and recurrent laryngeal nerves taken from twelve male cadavers. The sample was divided into two groups: those aged below 60 years (Adult) and those aged 60 years or more (Elderly). The material was evaluated under light microscopy coupled with an image analysis system. RESULTS: The total number of myelinic fibers from the superior laryngeal nerve was similar in both age groups; there was, however, a trend for a higher number of 1μm fibers in the adult group (p=0.0744). The adult group had a higher total number of myelinic fibers in the recurrent laryngeal nerve (p=0.0006), and this difference was seen in fibers with diameters betwee 1-3μm (p<0.007). The adult group had a higher total number of myelinic fibers in the laryngeal nerves (sum of superior laryngeal nerves and recurrent laryngeal nerves fibers) compared to the elderly group (p<0.0091). CONCLUSION:The total number of myelinic fibers in laryngeal nerves is higher for the group aged below 60 years