60,662 research outputs found
To what extent acute exposure to volcanic gases affects cells of the respiratory epithelium, peripheral oxygen saturation and lung funcion?
Dissertação de Mestrado, Ciências Biomédicas, 31 de julho de 2018, Universidade dos Açores.O vulcão das Furnas encontra-se localizado na parte oriental da ilha de São Miguel (Açores, Portugal), onde a actividade vulcânica é marcada por várias manifestações hidrotermais que emitem continuamente gases vulcânicos que são inalados pela população residente (exposição crónica) ou visitantes dessa freguesia (exposição aguda). Tendo em conta a atmosfera característica das Furnas e a falta de estudos sobre os efeitos causados pelos gases vulcânicos ao nível celular e os efeitos da exposição aguda aos gases vulcânicos, este estudo foi desenvolvido com o objetivo de responder a três questões: (1ª) Qual a constituição química do condensado dos gases vulcânicos das Furnas? (2ª) Quais são os efeitos resultantes da interação entre o condensado de gases vulcânicos e as células do epitélio respiratório (cells of the respiratory epithelium, abrev. CORE)? (3ª) Quais são os efeitos decorrentes de uma exposição aguda a gases vulcânicos em um grupo de voluntários, em relação à frequência cardíaca e pressão arterial, saturação periférica de oxigênio e parâmetros da função pulmonar?
Os resultados mostram que o condensado das fumarolas das Furnas é maioritariamente constituído por Ca, Na, Si e K. Quanto à exposição do CORE ao condensado de fumarola, os resultados são inconclusivos. Parece que, com o aumento do tempo de exposição, as células tendem a ter mais anomalias (isto é, danos no ADN, alterações morfológicas das células), bem como mais dificuldade em proliferar e em crescer. Estes efeitos podem ter sido causados por uma exposição consecutiva a ambos os condensados, mas também podem ter sido causados pelo decorrer do tempo em si, uma vez que o passar do tempo, as células tendem a acumular erros e a perder a sua capacidade proliferativa e viabilidade inicial por elas próprias. Os resultados da oximetria, espirometria, pressão arterial e frequência cardíaca obtidos da exposição aguda de um grupo de voluntários às fumarolas mostraram que apenas a frequência cardíaca foi afetada significativamente. A diminuição do valor da frequência cardíaca desde a pré-exposição até a pós-exposição indica que a exposição à fumarola e à natureza circundante teve um efeito calmo e relaxante nos voluntários. Tanto quanto foi possível determinar, esta é a primeira vez que tal estudo foi realizado.ABSTRACT: Furnas volcano is located in the eastern part of the island of São Miguel (Azores, Portugal), where volcanic activity is marked by several hydrothermal manifestations that continuously emit volcanic gases that are inhaled by the resident population (chronic exposure) or visitors to that village (acute exposure). Taking into account the characteristic atmosphere of Furnas and the lack of studies on the effects caused by volcanic gases at the cellular level and the effects from acute exposure to volcanic gases, this study was developed with the aim to answer three questions: (1st) What is the chemical constitution of Furnas volcanic gases condensate? (2nd) What are the effects resulting from the interaction between volcanic gases condensate and cells of the respiratory epithelium (abbr. CORE)? (3rd) What are the effects resulting from an acute exposure to volcanic gases on a group of volunteers, regarding heart rate and blood pressure, peripheral oxygen saturation and lung function parameters?
The results shows that the chemical constitution of Furnas fumarole condensate is mainly Ca, Na, Si and K. Regarding the exposure of CORE to the fumarole condensate the results are inconclusive. It appears that, with increasing time of exposure, cells tended to have more anomalies (i.e. DNA damage, cell morphological changes), as well as more difficulty to proliferate and to growth. These effects could have been caused by a consecutive exposure to both condensates, but it could also be caused by time itself, since with time cells tend to accumulate errors and lost their initial proliferative capacity and viability by themselves. The oximetry, spirometry, blood pressure and heart rate measurement results obtained from the acute exposure of a group of volunteers to the fumaroles showed that only the heart rate was significantly affected. The decrease in the heart rate value from the pre-exposure to the post-exposure indicates that the exposure to the fumarole, and the surrounding nature, had a calm and relaxing effect on the volunteers. As far as it was possible to determine, this is the first time that such a study was carried out
Do Freedom of Information Laws Decrease Corruption?
It has been argued that greater transparency is needed to reduce corruption. One way of increasing transparency is through the adoption of Freedom of Information (FOI) laws. This paper uses the introduction of FOI laws as a natural experiment to determine their effect on corruption. Using a sample of democratic countries and two different corruption indices, I find that countries that adopted FOI laws saw an increase in corruption. Results are robust throughout different specifications. Moreover, I find that countries with plurality systems potentially experienced a decrease in corruption following the adoption of FOI legislation. Having a parliamentary system, however, had no impact on the effect of the reform.Corruption; freedom of information; transparency; accountability
Can the Market Be Used to Preserve Land? The Case for Transfer of Development Rights
This paper discusses the use of a market-driven technique ? transfer of development rights ? to preserve land from development while guaranteeing the rights of property owners. While the technique is often used in the United States, Europe has a lot more urgency in land preservation but it is still lagging in the use of market based instruments such as transfer of development rights. Property ownership can be described as a bundle of rights, including the right to use, the right to exchange, and the right to convert. The transfer of development rights (TDR) technique assumes that the development rights of a parcel, as part of the right to convert, can be sold and used in another parcel. The motivation for the creation of a TDR program is the preservation of environmentally sensitive areas, agricultural land, open space, and historic landmarks. In the task of preserving these areas, TDR is thought to be the best technique since it is a market-type transaction involving low costs for the public, it is more effective than zoning in the protection of land and landmarks, and it provides compensation to landowners that alienate the development rights. The typical TDR program involves the landowner of a preservation or sending zone (or parcel) selling the development rights to a developer who will use these rights in an area designated as development or receiving zone (or parcel). In general, the receiving area allows higher density of construction, which becomes the incentive for developers to buy the development rights. A variation of this program occurs when government creates a TDR bank from which developers acquire rights to develop at higher densities and the government uses the money to purchase development rights in areas it wishes to protect. TDR banks can also help during economic recessions to sustain the price of certificates. The economic analysis argues that TDR programs should be preferred to zoning for four reasons. First, TDR programs are market-based alternatives and, therefore, entail less administrative costs then command-and-control regulation. Second, rezoning decisions frequently involve large rent-seeking costs, whereas TDR overcomes the market failure and increases the net benefits of regulation. Third, the certificates of development rights can be exchanged in the market and provide a compensation to the landowner for the loss of the right to develop. Fourth, in communities facing urban sprawl and suffering pressures to develop, the outcome of a TDR program is an efficient market allocation of land to its most valued use: the market maximizes the aggregate value of the land. The paper summarizes the economic arguments favoring the use of TDR programs and discusses the difficulties in implementing these programs in Europe where command-and-control regulation has been preferred over market-based solutions.
Deeper Integration and Voting on the Common European External Tariff
Since the 1987 Single European Act, the European Union has deepened its integration process. In the case of the determination of the common external tariff, deeper integration implies that the tariff reflected union-wide preferences. If integration is still shallow, though, the observed tariff will reflect the preferences of a pivotal national government. How governments voted, however, was not public information. This paper uses a unique dataset to test the deep vs. shallow integration hypothesis in an effort to shed light on how decisions are made in the EU. Results support the deep integration hypothesis.Collective decisions; deeper integration; tariffs; European Union; decisive voter
Scaling-laws of human broadcast communication enable distinction between human, corporate and robot Twitter users.
Human behaviour is highly individual by nature, yet statistical structures are emerging which seem to govern the actions of human beings collectively. Here we search for universal statistical laws dictating the timing of human actions in communication decisions. We focus on the distribution of the time interval between messages in human broadcast communication, as documented in Twitter, and study a collection of over 160,000 tweets for three user categories: personal (controlled by one person), managed (typically PR agency controlled) and bot-controlled (automated system). To test our hypothesis, we investigate whether it is possible to differentiate between user types based on tweet timing behaviour, independently of the content in messages. For this purpose, we developed a system to process a large amount of tweets for reality mining and implemented two simple probabilistic inference algorithms: 1. a naive Bayes classifier, which distinguishes between two and three account categories with classification performance of 84.6% and 75.8%, respectively and 2. a prediction algorithm to estimate the time of a users next tweet with an R2 ≈0.7. Our results show that we can reliably distinguish between the three user categories as well as predict the distribution of a users inter-message time with reasonable accuracy. More importantly, we identify a characteristic power-law decrease in the tail of inter-message time distribution by human users which is different from that obtained for managed and automated accounts. This result is evidence of a universal law that permeates the timing of human decisions in broadcast communication and extends the findings of several previous studies of peer-to-peer communication. © 2013 Tavares, Faisal
Ground States for a nonlinear Schr\"odinger system with sublinear coupling terms
We study the existence of ground states for the coupled Schr\"odinger system
\begin{equation} \left\{\begin{array}{lll} \displaystyle -\Delta
u_i+\lambda_i u_i= \mu_i |u_i|^{2q-2}u_i+\sum_{j\neq i}b_{ij}
|u_j|^q|u_i|^{q-2}u_i \\ u_i\in H^1(\mathbb{R}^n), \quad i=1,\ldots, d,
\end{array}\right. \end{equation} , for ,
(the so-called "symmetric attractive case") and
. We prove the existence of a nonnegative ground state
with radially decreasing. Moreover we show that,
for , such ground states are positive in all dimensions and for all
values of the parameters
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