903 research outputs found
Kinetics of quenching of hydrous feldspathic melts: Quantification using synthetic fluid inclusions
3D numerical simulation of hydro-acoustic waves registered during the 2012 negros-cebu earthquake
The paper investigates on the hydro-acoustic waves propagation caused by the underwater earthquake, occurred on 6 February 2012, between the Negros and Cebu islands, in the Philippines. Hydro-acoustic waves are pressure waves that propagate at the sound celerity in water. These waves can be triggered by the sudden vertical sea-bed movement, due to underwater earthquakes. The results of three dimensional numerical simulations, which solve the wave equation in a weakly compressible sea water domain are presented. The hydro-acoustic signal is compared to an underwater acoustic signal recorded during the event by a scuba diver, who was about 12 km far from the earthquake epicenter
The relation between energy consumption and developed land; a model for the metropolitan area of Barcelona
The study of the developed land and the energy consumption is part of a main project, which objective is the development of a model for the evaluation of the environmental and energy efficiency of the interaction (mobility) and land use structure (called as 'territorial functionality'), applied to the metropolitan area of Barcelona . One of the most important points of the main project is the modeling of energy consumption, and developed land produced by the territorial functionality. This paper presents the calibrations results of econometrics models (log-log) for developed land, and electricity consumption. The used information for those models was; built surface by activity (cadastre), coverings of land uses of Catalonia (CREAF), electric consumption by economic activity (CNAE), meteorological variables, and operating time of activities. The analysis was for the 164 municipalities of the metropolitan area of Barcelona. The electric consumption was analyzed in different categories of activities like as residential, industrial, trade, financial services, hotels, transport, education, public lighting, etc. The artificial area was differentiated in three categories; cadastre surface, streets, and developed land without cadastre. Overall, the results show that the extension of developed land depends (with 0.8 R2) mainly from single-family homes, followed by industrial activities, and finally sport activities. The trade activities induce a contraction of developed land, result that is consistent with agglomeration economies. The different models calibrated for energy consumption show a strong dependence (with R2 between 0.5 and 0.9) first with built surface, and second with other variables such as weather condition in the municipality (minimum temperature in summer), and average operating time of the activities (mean work time, shopping time, etc). Finally, the electric consumption by public lighting depends significantly on the developed land, representing the union between the two dimensions of the study.
Pressure-induced coordination change of Ti in silicate glass: a XANES study
The effect of pressure on titanium coordination in glasses, with composition K2TiSi4O11, quenched isobarically from liquids equilibrated at high pressure (5, 10, 15, 20, 25, 30 kbar respectively) and T=1600° C has been investigated by X-ray absorption spectroscopy (XAS). The XANES spectra collected at the Ti K-edge clearly show a variation with pressure that is related to changes in the geometrical environment around the Ti atoms. By comparison with spectra of standard materials, the XANES spectra of the glasses suggest a relatively low average coordination number (near 5) in samples quenched at low pressure and a higher coordination number (near 6) in samples quenched from the highest pressure. The combination of XANES data with density and compressibility measurements supports the idea that a mixture of 6- and lower coordinated (4- and/ or 5-coordinated) Ti geometries are present in the 1 bar glass, and an increasing proportion of 6-coordinated Ti occurs in the glasses synthesized at progressively higher pressures
X-ray absorption study of Ti-bearing silicate glasses
Ti K-edge XANES spectra have been collected on a series of Ti-bearing silicate glasses with metasilicate and tetrasilicate compositions. The intensity of the preedge feature in these spectra has been found to change with glass composition and varies from 29 to 58% (normalized intensity) suggesting a variation in structural environent around the absorbing atom. The pre-edge peak intensity increases for the alkali titanium tetrasilicate glasses from 35% to 58% in the order Li < Na < K < Rb, Cs whereas for the metasilicate compositions there is a maximum for the K-bearing glass. The pre-edge peak intensity remains constant for the alkaline earth titanium metasilicate glasses, Ca and Sr (34%) but increases slightly for Ba (41%). As the intensity of this feature is inversely correlated with coordination number, a comparison of the pre-edge intensity data for the investigated glasses with those of materials of known coordination number leads us to establish a regression equation and to infer that the average coordination number of Ti in these glasses ranges from 4.8 to 5.8. Large alkali cations appear to stabilize a relatively low average coordination number for Ti in silicate melts. The Ti structural environment results appear also to vary as a function of SiO2 content within the K2O-TiO2-SiO2 system. A number of physical properties of the melts from which these glasses were quenched and of other Ti-bearing silicate melts, have been determined in recent years. Clear evidence of a variable coordination number of Ti, consistent with the interpretation of the present XANES data is available from density measurements. These and other property determinations are compared with the present spectroscopic observations in an attempt to relate structure and properties in these melts which contain a major component with variable coordination number
Co-ocorrency between attention deficit hyperactivity disorder and psychoactive substances
Attention deficit/hyperactivity disorder (ADHD) is highly associated with substance use disorders (SUDs), both in clinical and community studies. Approximately 30% of subjects with SUDs present with comorbid ADHD, a prevalence rate significantly higher than that seen in the general population. The effect of ADHD on the development of SUDs have been subject to extensive studies. This article reviews the existing literature regarding: a) the nature of the association between ADHD and SUDs; b) the impact of ADHD on SUDs; c) the treatment of ADHD which co-occurs with SUDs. Finally an overview, from a predominantly clinical perspective, an integration of those data is proposed.Existe forte associação entre o transtorno de déficit de atenção/hiperatividade (TDAH) e o transtorno por uso de substâncias psicoativas (TUSP) em estudos clínicos e comunitários. Estimam-se que aproximadamente 30% dos sujeitos com TUSP apresentem comorbidade com o TDAH, taxa significativamente maior do que a vista na população geral. Vários estudos vêm analisando o possível efeito do TDAH no risco de desenvolvimento de TUSP. O presente artigo revisa a literatura disponível às seguintes questões: a) natureza da associação entre o TDAH e o TUSP; b) efeitos do TDAH no TUSP; c) tratamento do TDAH na concomitância do diagnóstico de TUSP. Por fim, é oferecida uma integração das diferentes informações, sob um enfoque predominantemente clínico.Universidade Luterana do BrasilUFRGS Hospital de Clínicas de Porto AlegreUniversidade Federal de São Paulo (UNIFESP) Unidade de Pesquisa em Álcool e DrogasUNIFESP, Unidade de Pesquisa em Álcool e DrogasSciEL
In Situ high temperature study of titanium coordination in a Rb-silicate glass and liquid to 1400°C
Palmitoylethanolamide dampens reactive astrogliosis and improves neuronal trophic support in a triple transgenic model of Alzheimer’s disease: in vitro and in vivo evidence
Alzheimer’s disease (AD) is a neurodegenerative disorder responsible for the majority of dementia cases in elderly people. It is widely accepted that the main hallmarks of AD are not only senile plaques and neurofibrillary tangles but also reactive astrogliosis, which often precedes detrimental deposits and neuronal atrophy. Such phenomenon facilitates the regeneration of neural networks; however, under some circumstances, like in AD, reactive astrogliosis is detrimental, depriving neurons of the homeostatic support, thus contributing to neuronal loss. We investigated the presence of reactive astrogliosis in 3×Tg-AD mice and the effects of palmitoylethanolamide (PEA), a well-documented anti-inflammatory molecule, by in vitro and in vivo studies. In vitro results revealed a basal reactive state in primary cortical 3×Tg-AD-derived astrocytes and the ability of PEA to counteract such phenomenon and improve viability of 3×Tg-AD-derived neurons. In vivo observations, performed using ultramicronized- (um-) PEA, a formulation endowed with best bioavailability, confirmed the efficacy of this compound. Moreover, the schedule of treatment, mimicking the clinic use (chronic daily administration), revealed its beneficial pharmacological properties in dampening reactive astrogliosis and promoting the glial neurosupportive function. Collectively, our results encourage further investigation on PEA effects, suggesting it as an alternative or adjunct treatment approach for innovative AD therapy
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