Bilayer polarity and its thermal dependency in the e(o) and e(d) phases of binary phosphatidylcholine/cholesterol mixtures

Diverse variations in membrane properties are observed in binary phosphatidylcholine/cholesterol mixtures. These mixtures are nonideal, displaying single or phase coexistence, depending on chemical composition and other thermodynamic parameters. When compared with pure phospholipid bilayers, there are changes in water permeability, bilayer thickness and thermomechanical properties, molecular packing and conformational freedom of phospholipid acyl chains, in internal dipolar potential and in lipid lateral diffusion. Based on the phase diagrams for DMPC/cholesterol and DPPC/cholesterol, we compare the equivalent polarity of pure bilayers with specific compositions of these mixtures, by using the Py empirical scale of polarity. Besides the contrast between pure and mixed lipid bilayers, we find that liquid-ordered and liquid-disordered (e(d)) phases display significantly different polarities. Moreover, in the e(o) phase, the polarities of bilayers and their thermal dependences vary with the chemical composition, showing noteworthy differences for cholesterol proportions at 35, 40, and 45 mol%. At 20 degrees C, for DMPC/ cholesterol at 35 and 45 mol%, the equivalent dielectric constants are 21.8 and 23.8, respectively. Additionally, we illustrate potential implications of polarity in various membrane-based processes and reactions, proposing that for cholesterol containing bilayers, it may also go along with the occurrence of lateral heterogeneity in biological membranes. (c) 2007 Elsevier B.V. All rights reserved.info:eu-repo/semantics/publishedVersio

A second-person model to anomalous social cognition

Reports of patients with schizophrenia show a fragmented and anomalous subjective experience. This pathological subjective experience, we suggest, can be related to the fact that disembodiment inhibits the possibility of intersubjective experience, and more importantly of common sense. In this paper, we ask how to investigate the anomalous experience both from qualitative and quantitative viewpoints. To our knowledge, few studies have focused on a clinical combination of both first- phenomenological assessment and third-person biological methods, especially for Schizophrenia, or ASD therapeutics and diagnosis. We will thus attempt to bring forward a second-person scientific design, accounting for both the first-person subjective experiential aspects, and respective third-person neurobiological correlates of embodied aesthetics in anomalous experience. From this proposal, we further explore the consequences to clinical and research practice

Motores de combustão interna

Este livro é a primeira obra extensa em lingua Portuguesa sobre motores de combustão interna, nomeadamente os de tracção automóvel. Embora tenha sido escrita como um elemento de estudo para alunos universitários de Engenheria mecânica, pretende também ser uma obra de referência para mecânicos, engenheiros ou aficcionados por automóveis e/ou motores. Está dividido em 11 capítulos, incluindo a descrição de motores e a história da sua evolução até aos nossos dias. Contém aspectos mais teóricos como a análise de ciclos e mais práticos como o teste de motores. Nele, o interessado poderá analisar o desempenho dos motores, prever as suas características e obter a informação necessária para os modelar e projectar. Por exemplo, o Cap.lO inclui as equações necessárias para projectar um escape "de rendimento" para motores a dois tempos. Esta obra integra assuntos não habituais em livros deste género. Nela pode encontrar-se uma descrição aprofundada sobre combustíveis, incluindo os usados pelos "dragsters top fuel" (nitro metano), o "aumentador de potência" N20 (que não é um combustível mas sim um oxidante), combustíveis menos correntes como o hidrogénio, os álcoois e os éteres. Nesse capítulo referem-se ainda os conhecidos bio-diesel (ésteres) e a forma como são produzidos, além de se descreverem os óleos lubrificantes, incluindo os sintéticos. Outros assuntos pouco frequentes neste tipo de obras passam pela descrição e projecto de salas de teste de motores, análise da variabilidade da combustão, descrição dos sistemas OBD, estudo minucioso do motor analisando o seu funcionamento por não menos que oito diferentes rendimentos, não incluindo as cinco relações (eficiências e rendimentos) apresentadas para analisar a lavagem dos motores a dois tempos. Para além da parte eminentemente teórica desta obra (que inclui a avaliação dos ciclos em carga parcial), sobressai o Cap.5 (com uma centena de páginas) dedicado à descrição exaustiva dos motores e dos seus vários componentes. Um subcapítulo é vocacionado aos motores de Formula 1. Actualmente assiste-se a uma grande evolução nos motores, da qual os novos sistemas de "common-rail" nos motores diesel e de injecção directa nos a gasolina são o resultado visível. Porém, outros progressos mais radicais estão a ser desenvolvidos, provavelmente levando a tipos de motores de combustão "híbrida" entre os que consomem gasolina e gasóleo. Estes tipos de combustão têm várias denominações, mas são geralmente conhecidos por CAI (controlled auto ignition) e por HCCI (homogeneous charge compression ignition), assunto exposto no Cap.8, e que se prevê seja determinante no futuro dos motores. Os motores de combustão interna são máquinas intensamente usadas no mundo sendo, simultaneamente, uma fonte de satisfação mas também de problemas como os ambientais. Assim, espera-se que a leitura desta obra possa levar ao melhor conhecimento e à utilização destas máquinas admiráveis

Growth, Reform Indicators and Policy Complementaries

This paper discusses the design of structural policies by relating second-best results and the complementarity of reforms. It computes a complementarity index based on structural reform indicators compiled by the EBRD for transition countries, assuming that the run-up to EU integration corresponds to a nearly complete policy cycle. Using econometric panel estimates, the level of reforms and changes in their complementarity are found to be positively related to output growth, corrected for endogeneity, and given initial conditions and the extent of macroeconomic stabilisation.

Growth, Reform indicators and Policy complementarities

This paper discusses the design of structural policies by relating second-best results and the complementarity of reforms. It computes a complementarity index based on structural reform indicators compiled by the EBRD for transition countries, assuming that the run-up to EU integration corresponds to a nearly complete policy cycle. Using econometric panel estimates, the level of reforms and changes in their complementarity are found to be positively related to output growth, corrected for endogeneity, and given initial conditions and the extent of macroeconomic stabilisation.

Growth, Reform Indicators and Policy Complementarities.

In order to assess the growth implications of policy complementarities, this paper applies second-best results to reform indicators. During the transition from central planning to EU integration, which corresponds to a policy cycle, a complementarity index based on structural indicators compiled by the European Bank for Reconstruc- tion and Development (EBRD) decreases and then increases while the level of reforms tends to rise throughout. Corrected for initial conditions, the extent of macroeconomic stabilization and endogeneity, the level of reforms and changes in their complementarity are found to be positively related to output growth. The study uses panel data for 27 countries between 1989 and 2004.Second-best; complementarity; structural reforms; reform indicators; economic growth; transition; panel data;

Spectroscopic direct detection of reflected light from extra-solar planets

At optical wavelengths, an exoplanet's signature is essentially reflected light from the host star - several orders of magnitude fainter. Since it is superimposed on the star spectrum its detection has been a difficult observational challenge. However, the development of a new generation of instruments like ESPRESSO and next generation telescopes like the E-ELT put us in a privileged position to detect these planets' reflected light as we will have access to extremely high signal-to-noise ratio spectra. With this work, we propose an alternative approach for the direct detection of the reflected light of an exoplanet. We simulated observations with ESPRESSO@VLT and HIRES@E-ELT of several star+planet systems, encompassing 10h of the most favourable orbital phases. To the simulated spectra we applied the Cross Correlation Function to operate in a much higher signal-to-noise ratio domain than when compared with the spectra. The use of the Cross-Correlation Function permitted us to recover the simulated the planet signals at a level above 3 \sigma_{noise} significance on several prototypical (e.g., Neptune type planet with a 2 days orbit with the VLT at 4.4 \sigma_{noise} significance) and real planetary systems (e.g., 55 Cnc e with the E-ELT at 4.9 \sigma_{noise} significance). Even by using a more pessimistic approach to the noise level estimation, where systematics in the spectra increase the noise 2-3 times, the detection of the reflected light from large close-orbit planets is possible. We have also shown that this kind of study is currently within reach of current instruments and telescopes (e.g., 51 Peg b with the VLT at 5.2 \sigma_{noise} significance), although at the limit of their capabilities.Comment: Accepted for Publication on MNRAS: 2013 August 29; Online Article: http://mnras.oxfordjournals.org/content/early/2013/09/27/mnras.stt1642; 5 Figures, 11 page

Binary sequences with prescribed autocorrelations

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