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

Comparative analysis of digital artifact persistence between file format

As we know digital forensics is a scientific examination and analysis of data that when it held on, or where it is retrieved from so that the information collected can be used as evidence in a court of law. Nowadays, digital evidence are very useful to provide when case in court. The deleted file of document, audio or image can be recover back as digital artifact [1]. Therefore, it is very clear from the experience that digital artifact are important witnesses to care

Marketing management capability:the construct and its dimensions: an examination of managers’ and entrepreneurs’ perceptions in a retail setting

Purpose: This paper aims to explore the relationship between corporate cultural/intangible assets and marketing capabilities by examining managers’ and entrepreneurs’ perceptions in a retail setting.Design/methodology/approach: Nineteen face-to-face interviews were conducted with UK small and medium sized enterprise (SMEs) managers and entrepreneurs to identify six sub-capabilities that form marketing capability. The authors further validated the relationship between marketing sub-capabilities and its antecedent tangible and intangible assets. The qualitative approach used provided a deeper insight into the motivations, perceptions and associations of the stakeholders behind these intangible concepts, and their relationships with their customers.Findings: The research identified that there is a strong relationship between tangible and intangible assets, their components and the following capabilities: corporate/brand identity management, market sensing, customer relationship, social media/communication, design/innovation management and performance management. In addition, companies need to understand clearly what tangible and intangible assets comprise these capabilities. Where performance management is one of the key internal capabilities, companies must highlight the importance of strong cultural assets that substantially contribute to a company’s performance.Originality/value: Previous work on dynamic capability analysis is too generic, predominantly relating to the manufacturing sector, and/or focussing on using a single case study example. This study extends the concept of marketing capability in a retail setting by identifying six sub-capabilities and describing the relationship of each with tangible and intangible assets. Through extensive qualitative analysis, the authors provide evidence that by fully exploiting their embedded culture and other intangible components, companies can more favourably engage with their customers to attain a sustainable competitive advantage.</p

Fluid-solid transition in unsteady, homogeneous, granular shear flows

Discrete element numerical simulations of unsteady, homogeneous shear flows have been performed by instantly applying a constant shear rate to a random, static, isotropic assembly of identical, soft, frictional spheres at either zero or finite pressure by keeping constant the solid volume fraction until the steady state is reached. If the system is slowly sheared, or, equivalently, if the particles are sufficiently rigid, the granular material exhibits either large or small fluctuations in the evolving pressure, depending whether the average number of contacts per particle (coordination number) is less or larger than a critical value. The amplitude of the pressure fluctuations is rate-dependent when the coordination number is less than the critical and rate-independent otherwise, signatures of fluid-like and solid-like behaviour, respectively. The same critical coordination number has been previously found to represent the minimum value at which rate-independent components of the stresses develop in steady, simple shearing and the jamming transition in isotropic random packings. The observed complex behaviour of the measured pressure in the fluid-solid transition clearly suggests the need for incorporating in a nontrivial way the coordination number, the solid volume fraction, the particle stiffness and the intensity of the particle agitation in constitutive models for the onset and the arrest of granular flows.Comment: 20 pages, 14 figures, submitted to Granular Matte

Computational results for Constrained Minimum Spanning Trees in Flow Networks

In this work, we address the problem of finding a minimum cost spanning tree on a single source flow network. The tree must span all vertices in the given network and satisfy customer demands at a minimum cost. The total cost is given by the summation of the arc setup costs and of the nonlinear flow routing costs over all used arcs. Furthermore, we restrict the trees of interest by imposing a maximum number of arcs on the longest arc emanating from the single source vertex. We propose a dynamic programming model an solution procedure to solve this problem exactly. Intensive computational experiments were performed using randomly generated test problems and the results obtained are reported. From them we can conclude that the method performance is independent of the type of cost functions considered and improves with the tightness of the constrains.Dynamic programming, network flows, constrained trees, general nonlinear costs

STUDY OF PARTIAL STROKE TEST FOR METSO NELES EMERGENCY SHUTDOWN VALVE

This report essentially discusses the basic understanding and details of the project entitled "A Study of Partial Stroke Test for Metso Neles Emergency Shutdown (ESD) Valve". Since this project is a collaboration between Univcrsiti Teknologi Petronas (UTP) and PETRONAS Improvement Working Group (IWG) of Skill Group 14 (SKG14), discussion session is conducted once in a few months to compare the latest update of valves performance from three vendors, namely, FISHER, METSO NELES. and MESONEILAN that may be used in PETRONAS plants if satisfies the required standard

Plane shear flows of frictionless spheres: Kinetic theory and 3D soft-sphere discrete element method simulations

We use existing 3D Discrete Element simulations of simple shear flows of spheres to evaluate the radial distribution function at contact that enables kinetic theory to correctly predict the pressure and the shear stress, for different values of the collisional coefficient of restitution. Then, we perform 3D Discrete Element simulations of plane flows of frictionless, inelastic spheres, sheared between walls made bumpy by gluing particles in a regular array, at fixed average volume fraction and distance between the walls. The results of the numerical simulations are used to derive boundary conditions appropriated in the cases of large and small bumpiness. Those boundary conditions are, then, employed to numerically integrate the differential equations of Extended Kinetic Theory, where the breaking of the molecular chaos assumption at volume fraction larger than 0.49 is taken into account in the expression of the dissipation rate. We show that the Extended Kinetic Theory is in very good agreement with the numerical simulations, even for coefficients of restitution as low as 0.50. When the bumpiness is increased, we observe that some of the flowing particles are stuck in the gaps between the wall spheres. As a consequence, the walls are more dissipative than expected, and the flows resemble simple shear flows, i.e., flows of rather constant volume fraction and granular temperature

Atuação do curso de turismo nas escolas da rede pública Municipal de Pelotas: Reflexões sobre turismo, educação patrimonial e cidadania

Trabalho apresentado no 31º SEURS - Seminário de Extensão Universitária da Região Sul, realizado em Florianópolis, SC, no período de 04 a 07 de agosto de 2013 - Universidade Federal de Santa Catarina.Nossa proposta é apresentar algumas reflexões das ações realizadas pelo Curso de Bacharelado em Turismo da UFPel nas escolas da rede pública municipal de Pelotas, inseridas no Projeto de Extensão “Turismo, Educação e Cidadania”. O projeto tem por objetivo desenvolver ações junto aos alunos da rede municipal de Pelotas, a fim de oportunizar a reflexão sobre as temáticas turismo, educação patrimonial e cidadania. Desse modo, visa inserir o acadêmico do curso turismo na comunidade onde está a universidade, propiciando o crescimento pessoal e profissional do mesmo. O projeto pretende incentivar os alunos da rede municipal a valorizar as próprias vivências da comunidade, incentivando a participação local que é a melhor preparação para a atuação dos cidadãos em nível global. A metodologia consiste na realização de encontros com turmas do 4º ano do ensino fundamental, pois é nessa série que os alunos começam a trabalhar a sua cidade. Durante os encontros, são desenvolvidas diversas atividades individuais e coletivas, como passeios, desenhos, jogos, brincadeiras e debates, com a intenção de estimular as discussões de questões sociais, ambientais, históricas e culturais da comunidade, relacionadas à atividade turística. As atividades desenvolvidas possibilitam aos alunos uma relação mais direta com seu bairro, com a sua cidade, com seu cotidiano, o que reforça e valoriza o elo na e com a comunidade