230 research outputs found
Upper Paleozoic Dikes of the Marão Mountain (Northern Portugal); results of intra orogenic Extension?
[Abstract] In the Marão mountain occur hercynian mafic veins cutting the Schistose Formation of the Landeilian age. The geochemistry of these rocks present high concentrations on Ti ,P, Zr, Nb, Ba, and REE (Ti O2= 1.23-1,39 %, P2O5= 1.32-1,60 %, Zr = 565-641 ppm, Nb= 33-46 ppm, Ba = 2531-3219 ppm, ΣREE = 295-430 ppm) and indicate significant REE fractionation (CeN/ Y bN= 10.46) similar to that reported for alkaline mafic rocks. These characteristics and their patterns in THOMPSON (1984) diagram are typical of alkaline rocks. The dikes intrusion occurred in a late stage of the tectonic evolution of the Centro-Iberian autochthon prior to the granitic magmatic phase. Their intrusion was facilitated, either by the reorientation of the stress field due to the emplacement of the NW Iberian nappe complex or local extensions common in transpressive regimes. This geodynamical context could produce the generation of alkaline magmatism due to partial melting of the upper mantle, induced by adiabatical decompression in the major crustal NW-SE shear zones
Early evolution of a stratospheric volcanic eruption cloud as observed with TOMS and AVHRR
This paper is a detailed study of remote sensing data from the total ozone mapping spectrometer (TOMS) and the advanced very high resolution radiometer (AVHRR) satellite detectors, of the 1982 eruption of El Chichón, Mexico. The volcanic cloud/atmosphere interactions in the first four days of this eruption were investigated by combining ultraviolet retrievals to estimate the mass of sulfur dioxide in the volcanic cloud [Krueger et al., 1995] with thermal infrared retrievals of the size, optical depth, and mass of fine-grained (1–10 μm radius) volcanic ash [Wen and Rose, 1994]. Our study provides the first direct evidence of gravitational separation of ash from a stratospheric, gas-rich, plinian eruption column and documents the marked differences in residence times of volcanic ash and sulfur dioxide in volcanic clouds. The eruption column reached as high as 32 km [Carey and Sigurdsson, 1986] and was injected into an atmosphere with a strong wind shear, which allowed for an observation of the separation of sulfur dioxide and volcanic ash. The upper, more sulfur dioxide-rich part of the cloud was transported to the west in the stratosphere, while the fine-grained ash traveled to the south in the troposphere. The mass of sulfur dioxide released was estimated at 7.1 × 109 kg with the mass decreasing by approximately 4% 1 day after the peak. The mass of fine-grained volcanic ash detected was estimated at 6.5 × 109 kg, amounting to about 0.7% of the estimated mass of the ash which fell out in the mapped ash blanket close to the volcano. Over the following days, 98% of this remaining fine ash was removed from the volcanic cloud, and the effective radius of ash in the volcanic cloud decreased from about 8 μm to about 4 μm
Illuminating Polysulfide Distribution in Lithium Sulfur Batteries; Tracking Polysulfide Shuttle Using Operando Optical Fluorescence Microscopy
High-energy-density lithium sulfur (Li–S) batteries suffer heavily from the polysulfide shuttle effect, a result of the dissolution and transport of intermediate polysulfides from the cathode, into the electrolyte, and onto the anode, leading to rapid cell degradation. If this primary mechanism of cell failure is to be overcome, the distribution, dynamics, and degree of polysulfide transport must first be understood in depth. In this work, operando optical fluorescence microscope imaging of optically accessible Li–S cells is shown to enable real-time qualitative visualization of the spatial distribution of lithium polysulfides, both within the electrolyte and porous cathode. Quantitative determinations of spatial concentration are also possible at a low enough concentration. The distribution throughout cycling is monitored, including direct observation of polysulfide shuttling to the anode and consequent dendrite formation. This was enabled through the optimization of a selective fluorescent dye, verified to fluoresce proportionally with concentration of polysulfides within Li–S cells. This ability to directly and conveniently track the spatial distribution of soluble polysulfide intermediates in Li–S battery electrolytes, while the cell operates, has the potential to have a widespread impact across the field, for example, by enabling the influence of a variety of polysulfide mitigation strategies to be assessed and optimized, including in this work the LiNO3 additive
Law, Liberty and the Rule of Law (in a Constitutional Democracy)
In the hunt for a better--and more substantial--awareness of the “law,” The author intends to analyze the different notions related to the “rule of law” and to criticize the conceptions that equate it either to the sum of “law” and “rule” or to the formal assertion that “law rules,” regardless of its relationship to certain principles, including both “negative” and “positive” liberties. Instead, he pretends to scrutinize the principles of the “rule of law,” in general, and in a “constitutional democracy,” in particular, to conclude that the tendency to reduce the “democratic principle” to the “majority rule” (or “majority principle”), i.e. to whatever pleases the majority, as part of the “positive liberty,” is contrary both to the “negative liberty” and to the “rule of law” itself
Long-term Psychological and Occupational Effects of Providing Hospital Healthcare during SARS Outbreak
TOC Summary Line: Healthcare workers in hospitals affected by SARS experience increased psychological stress 1–2 years after the outbreak
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Life satisfaction and confidence in national institutions: evidence from South America
A number of South American countries experienced turbulent democratic, political and economic upheaval over the last 40 years in the form of coup d’états in the 1970s, tumultuous elections, and repeated severe economic crises, some of which happened fairly recently. Starting in 2010, a number of court proceedings across the region have made past military coup d’états the focus of national conversations. South American citizens may, therefore, have lost confidence in national institutions that have repeatedly disappointed their trust and expectations; a situation with potentially detrimental effects on their well-being. Using eight waves of the Gallup World Poll collected between 2009 and 2016 across ten South American countries, we investigate to what extent people’s confidence in financial institutions, the honesty of elections, the military, the judicial system, the national government and the police is associated with people’s current and expectation of future life satisfaction. We find that people who report confidence in these six institutions rate their current and expected life satisfaction, on average, to be higher than those who lack these types of institutional confidence, even after controlling for demographic factors and macroeconomic indicators. In addition, we investigate changes over time for all six measures of confidence in institutions as well as for current and expectation of future life satisfaction. Our results suggest that governments’ investments in well-functioning institutions may contribute positively to subjective well-being in a society. However, our analysis is correlational and we thus cannot rule out reverse causality
The national inventory of geological heritage: methodological approach and results
A existência de um inventário nacional de património geológico é fundamental para se poderem implementar estratégias de geoconservação. Este trabalho apresenta a metodologia usada no desenvolvimento do mais completo inventário de geossítios, realizado até ao momento em Portugal, assim como os principais resultados obtidos. O inventário vai integrar o Sistema de Informação do Património Natural e o Cadastro Nacional dos Valores Naturais Classificados, ambos geridos pelo Instituto de Conservação da Natureza e da Biodiversidade.The existence of a national inventory of the geological heritage is of paramount importance for the implementation of a geoconservation strategy. This paper presents the methodological approach used to produce the most complete geosites inventory in Portugal, so far, and the obtained results. This inventory will be uploaded into the National Database of Natural Heritage managed by the Portuguese authority for nature conservation.Este trabalho é apoiado pela Fundação para a Ciência e a Tecnologia, através do financiamento plurianual do CGUP e do projecto de investigação “Identificação, caracterização e conservação do património geológico: uma estratégia de geoconservação para Portugal” (PTDC/CTE-GEX/64966/2006).info:eu-repo/semantics/publishedVersio
Agamben’s Grammar of the Secret Under the Sign of the Law
This paper suggests that a grammar of the secret forms a concept in Agamben’s work, a gap that grounds the enigma of sovereignty. Between the Indo-European *krei, *se, and *per themes, the secret is etymologically linked to the logics of separation and potentiality that together enable the pliant and emergent structure of sovereignty. Sovereignty’s logic of separation meets the logic of relation in the form of abandonment: the point at which division has exhausted itself and reaches an indivisible element, bare life, the exception separated from the form of life and captured in a separate sphere. The arcanum imperii of sovereignty and the cipher of bare life are held together in the relation of the ban as the twin secrets of biopower, maintained by the potentiality of law that works itself as a concealed, inscrutable force. But the ‘real’ secret of sovereignty, I suggest, is its dialectical reversibility, the point at which the concept of the secret is met by its own immanent unworking by the critic and scribe under the *krei theme, and subject to abandonment through the work of profanation; here, different species of the secret are thrown against one another, one order undoing the other. The secret founded upon the sacred is displaced by Agamben’s critical orientation toward the immanent: what is immanent is both potential and hiddenness
Iron status and Helicobacter pylori infection in symptomatic children: an international multi-centered study
Objective:Iron deficiency (ID) and iron deficiency anaemia (IDA) are global major public health problems, particularly in developing countries. Whilst an association between H. pylori infection and ID/IDA has been proposed in the literature, currently there is no consensus. We studied the effects of H. pylori infection on ID/IDA in a cohort of children undergoing upper gastrointestinal endoscopy for upper abdominal pain in two developing and one developed country.Methods:In total 311 children (mean age 10.7±3.2 years) from Latin America - Belo Horizonte/Brazil (n = 125), Santiago/Chile (n = 105) - and London/UK (n = 81), were studied. Gastric and duodenal biopsies were obtained for evaluation of histology and H. pylori status and blood samples for parameters of ID/IDA.Results:The prevalence of H. pylori infection was 27.7% being significantly higher (p<0.001) in Latin America (35%) than in UK (7%). Multiple linear regression models revealed H. pylori infection as a significant predictor of low ferritin and haemoglobin concentrations in children from Latin-America. A negative correlation was observed between MCV (r = -0.26; p = 0.01) and MCH (r = -0.27; p = 0.01) values and the degree of antral chronic inflammation, and between MCH and the degree of corpus chronic (r = -0.29, p = 0.008) and active (r = -0.27, p = 0.002) inflammation.Conclusions:This study demonstrates that H. pylori infection in children influences the serum ferritin and haemoglobin concentrations, markers of early depletion of iron stores and anaemia respectively
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