Showing papers by "University of Minho published in 2011"
University of Maryland, College Park1, Queen's University2, Cornell University3, University of Minnesota4, Nanyang Technological University5, McKinsey & Company6, Koç University7, Jacobs University Bremen8, University of Minho9, The Chinese University of Hong Kong10, Indian Institute of Management Ahmedabad11, Pontifical Catholic University of Peru12, University of Valencia13, Johannes Kepler University of Linz14, Victoria University of Wellington15, Hungarian Academy of Sciences16, National and Kapodistrian University of Athens17, La Trobe University18, University of Melbourne19, Sungkyunkwan University20, ESSEC Business School21, University of San Diego22, Katholieke Universiteit Leuven23, University of Patras24, Human Sciences Research Council25, ODESSA26, University of Tartu27, Norwegian School of Economics28, University of Koblenz and Landau29, University of Sussex30, University of Sindh31, Gakushuin University32, University of Groningen33, University of Tokyo34
TL;DR: The differences across cultures in the enforcement of conformity may reflect their specific histories and advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.
Abstract: With data from 33 nations, we illustrate the differences between cultures that are tight (have many strong norms and a low tolerance of deviant behavior) versus loose (have weak social norms and a high tolerance of deviant behavior). Tightness-looseness is part of a complex, loosely integrated multilevel system that comprises distal ecological and historical threats (e.g., high population density, resource scarcity, a history of territorial conflict, and disease and environmental threats), broad versus narrow socialization in societal institutions (e.g., autocracy, media regulations), the strength of everyday recurring situations, and micro-level psychological affordances (e.g., prevention self-guides, high regulatory strength, need for structure). This research advances knowledge that can foster cross-cultural understanding in a world of increasing global interdependence and has implications for modeling cultural change.
1,895 citations
TL;DR: In this paper, the authors provided an overview regarding coffee and its main industrial residues, including coffee silverskin and spent coffee grounds, obtained during the beans roasting and the process to prepare instant coffee, respectively.
Abstract: Coffee is one of the most consumed beverages in the world and is the second largest traded commodity after petroleum. Due to the great demand of this product, large amounts of residues are generated in the coffee industry, which are toxic and represent serious environmental problems. Coffee silverskin and spent coffee grounds are the main coffee industry residues, obtained during the beans roasting, and the process to prepare “instant coffee”, respectively. Recently, some attempts have been made to use these residues for energy or value-added compounds production, as strategies to reduce their toxicity levels, while adding value to them. The present article provides an overview regarding coffee and its main industrial residues. In a first part, the composition of beans and their processing, as well as data about the coffee world production and exportation, are presented. In the sequence, the characteristics, chemical composition, and application of the main coffee industry residues are reviewed. Based on these data, it was concluded that coffee may be considered as one of the most valuable primary products in world trade, crucial to the economies and politics of many developing countries since its cultivation, processing, trading, transportation, and marketing provide employment for millions of people. As a consequence of this big market, the reuse of the main coffee industry residues is of large importance from environmental and economical viewpoints.
759 citations
TL;DR: The aim of this review is to focus on the production and extraction of bioactive phenolic compounds from natural sources by SSF, and the characteristics of SSF systems and variables that affect the product formation by this process are reviewed.
574 citations
TL;DR: In this article, a new project developed by a cross-country team of researchers, with the aim of studying the hedonic and eudaimonic components of happiness through a mixed method approach combining both qualitative and quantitative analyses, was presented.
Abstract: This paper illustrates a new project developed by a cross-country team of researchers, with the aim of studying the hedonic and eudaimonic components of happiness through a mixed method approach combining both qualitative and quantitative analyses. Data were collected from 666 participants in Australia, Croatia, Germany, Italy, Portugal, Spain, and South Africa. A major aim of the study was to examine definitions and experiences of happiness using open-ended questions. Among the components of well-being traditionally associated with the eudaimonic approach, meaning in particular was explored in terms of constituents, relevance, and subjective experience. The Satisfaction With Life Scale (SWLS) was also administered to quantitatively assess the hedonic dimension of happiness. Results showed that happiness was primarily defined as a condition of psychological balance and harmony. Among the different life domains, family and social relations were prominently associated with happiness and meaningfulness. The quantitative analyses highlighted the relationship between happiness, meaningfulness, and satisfaction with life, as well as the different and complementary contributions of each component to well-being. At the theoretical and methodological levels, findings suggest the importance of jointly investigating happiness and its relationship with other dimensions of well-being, in order to detect differences and synergies among them.
553 citations
TL;DR: Fluorescence images of cross-sections of scaffolds revealed that scaffolds with pore size gradients induce a more homogeneous distribution of cells within the scaffold, improving seeding efficiency from ∼35% in homogeneous scaffolds to ∼70% under static culture conditions.
485 citations
TL;DR: In this paper, the particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transversal momentum and the charged-particle multiplicity are measured.
Abstract: Measurements are presented from proton-proton collisions at centre-of-mass energies of root s = 0.9, 2.36 and 7 TeV recorded with the ATLAS detector at the LHC. Events were collected using a single-arm minimum-bias trigger. The charged-particle multiplicity, its dependence on transverse momentum and pseudorapidity and the relationship between the mean transverse momentum and charged-particle multiplicity are measured. Measurements in different regions of phase space are shown, providing diffraction-reduced measurements as well as more inclusive ones. The observed distributions are corrected to well-defined phase-space regions, using model-independent corrections. The results are compared to each other and to various Monte Carlo (MC) models, including a new AMBT1 pythia6 tune. In all the kinematic regions considered, the particle multiplicities are higher than predicted by the MC models. The central charged-particle multiplicity per event and unit of pseudorapidity, for tracks with p(T) > 100 MeV, is measured to be 3.483 +/- 0.009 (stat) +/- 0.106 (syst) at root s = 0.9 TeV and 5.630 +/- 0.003 (stat) +/- 0.169 (syst) at root s = 7 TeV.
435 citations
TL;DR: In this paper, the use of vegetable fibres as reinforcement in cement based materials is discussed, and the compatibility between the fibres and the cement matrix and also how they influence cement properties.
426 citations
TL;DR: In this paper, the authors reviewed current knowledge about nanotechnology and nanomaterials used by the construction industry, including the use of nanoparticles to increase the strength and durability of cimentitious composites.
410 citations
TL;DR: In this article, a dilute acid hydrolysis aiming to recover the hemicellulose sugars was performed on spent coffee grounds (SCG), the residual materials obtained during the processing of raw coffee powder to prepare instant coffee, are the main coffee industry residues.
343 citations
TL;DR: In this paper, the authors used methanol as solvent at different concentrations (20-100%), solvent/solid ratios (10-40 ml/g SCG), and extraction times (30- 90 min), and evaluated the influence of these operational variables on the content of total phenolic compounds and antioxidant activity of the produced extracts.
332 citations
TL;DR: In this article, the authors evaluated starch accumulation in Chlorella vulgaris P12 under different initial concentrations of nitrogen (0−2.2 ) and iron (0 −0.08 ) sources, using a central composite design (CCD) for two factors.
TL;DR: In this article, a microwave-assisted extraction (MAE) method was used to extract fucoidan from brown seaweed Fucus vesiculosus under different conditions of pressure (30-120psi), extraction time (1-31min), and alga/water ratio (1/25 to 5/25 g/ml−1).
10 Oct 2011
TL;DR: The Conflict-free Replicated Data Type (CRDT) as discussed by the authors is a data type that is guaranteed to converge in a self-stabilising manner, despite any number of failures.
Abstract: Replicating data under Eventual Consistency (EC) allows any replica to accept updates without remote synchronisation. This ensures performance and scalability in large-scale distributed systems (e.g., clouds). However, published EC approaches are ad-hoc and error-prone. Under a formal Strong Eventual Consistency (SEC) model, we study sufficient conditions for convergence. A data type that satisfies these conditions is called a Conflict-free Replicated Data Type (CRDT). Replicas of any CRDT are guaranteed to converge in a self-stabilising manner, despite any number of failures. This paper formalises two popular approaches (state- and operation-based) and their relevant sufficient conditions. We study a number of useful CRDTs, such as sets with clean semantics, supporting both add and remove operations, and consider in depth the more complex Graph data type. CRDT types can be composed to develop large-scale distributed applications, and have interesting theoretical properties.
TL;DR: In this article, a general and comprehensive analysis on the continuous contact force models for soft materials in multibody dynamics is presented throughout this work, and the force models are developed based on the foundation of the Hertz law together with a hysteresis damping parameter that accounts for the energy dissipation during the contact process.
Abstract: A general and comprehensive analysis on the continuous contact force models for soft materials in multibody dynamics is presented throughout this work. The force models are developed based on the foundation of the Hertz law together with a hysteresis damping parameter that accounts for the energy dissipation during the contact process. In a simple way, these contact force models are based on the analysis and development of three main issues: (i) the dissipated energy associated with the coefficient of restitution that includes the balance of kinetic energy and the conservation of the linear momentum between the initial and final instant of contact; (ii) the stored elastic energy, representing part of initial kinetic energy, which is evaluated as the work done by the contact force developed during the contact process; (iii) the dissipated energy due to internal damping, which is evaluated by modeling the contact process as a single degree-of- freedom system to obtain a hysteresis damping factor. This factor takes into account the geometrical and material properties, as well as the kinematic characteristics of the contacting bodies. This approach has the great merit that can be used for contact problems involving materials with low or moderate values of coefficient of restitution and, therefore, accommodate high amount of energy dissipation. In addition, the resulting contact force model is suitable to be included into the equations of motion of a multibody system and contributes to their stable numerical resolution. A demonstrative example of application is used to provide the results that support the analysis and discussion of procedures and methodologies described in this work.
TL;DR: In this article, the authors use cross-wavelet analysis to decompose the time-frequency effects of oil price changes on the macroeconomy and argue that the relation between oil prices and industrial production is not clear-cut.
Abstract: We use (cross) wavelet analysis to decompose the time–frequency effects of oil price changes on the macroeconomy. We argue that the relation between oil prices and industrial production is not clear-cut. There are periods and frequencies where the causality runs from one variable to the other and vice-versa, justifying some instability in the empirical evidence about the macroeconomic effects of oil price shocks. We also show that the volatility of both the inflation rate and the industrial output growth rate started to decrease in the decades of 1950 and 1960.
TL;DR: In this paper, the authors use wavelet analysis to study business cycle synchronization across the EU-15 and the Euro-12 countries and find that the French business cycle has been leading the German business cycle as well as the rest of Europe.
TL;DR: In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications, and the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.
Abstract: As life expectancy increases, malfunction or loss of tissue caused by injury or disease leads to reduced quality of life in many patients at significant socioeconomic cost. Even though major progress has been made in the field of bone tissue engineering, present therapies, such as bone grafts, still have limitations. Current research on biodegradable polymers is emerging, combining these structures with osteogenic cells, as an alternative to autologous bone grafts. Different types of biodegradable materials have been proposed for the preparation of three-dimensional porous scaffolds for bone tissue engineering. Among them, natural polymers are one of the most attractive options, mainly due to their similarities with extracellular matrix, chemical versatility, good biological performance, and inherent cellular interactions. In this review, special attention is given to chitosan as a biomaterial for bone tissue engineering applications. An extensive literature survey was performed on the preparation of chitosan scaffolds and their in vitro biological performance as well as their potential to facilitate in vivo bone regeneration. The present review also aims to offer the reader a general overview of all components needed to engineer new bone tissue. It gives a brief background on bone biology, followed by an explanation of all components in bone tissue engineering, as well as describing different tissue engineering strategies. Moreover, also discussed are the typical models used to evaluate in vitro functionality of a tissue-engineered construct and in vivo models to assess the potential to regenerate bone tissue are discussed.
TL;DR: Cutinases from Thermobifida cellulosilytica DSM44535 and fusca DSM44342 hydrolyzing poly(ethylene terephthalate) (PET) were successfully cloned and expressed in E.coli BL21-Gold(DE3).
Abstract: In this study cutinases from Thermobifida cellulosilytica DSM44535 (Thc_Cut1 and Thc_Cut2) and Thermobifida fusca DSM44342 (Thf42_Cut1) hydrolyzing poly(ethylene terephthalate) (PET) were successfully cloned and expressed in E.coli BL21-Gold(DE3). Their ability to hydrolyze PET was compared with other enzymes hydrolyzing natural polyesters, including the PHA depolymerase (ePhaZmcl) from Pseudomonas fluorescens and two cutinases from T. fusca KW3. The three isolated Thermobifida cutinases are very similar (only a maximum of 18 amino acid differences) but yet had different kinetic parameters on soluble substrates. Their kcat and Km values on pNP–acetate were in the ranges 2.4–211.9 s–1 and 127–200 μM while on pNP–butyrate they showed kcat and Km values between 5.3 and 195.1 s–1 and between 1483 and 2133 μM. Thc_Cut1 released highest amounts of MHET and terephthalic acid from PET and bis(benzoyloxyethyl) terephthalate (3PET) with the highest concomitant increase in PET hydrophilicity as indicated by water co...
TL;DR: The full understanding of the plant cell complex defense mechanisms under stress may allow for the engineering of more tolerant plants or the optimization of cultivation practices to improve yield and productivity, which is crucial at the present time as food resources are progressively scarce.
Abstract: Plants are generally well adapted to a wide range of environmental conditions. Even though they have notably prospered in our planet, stressful conditions such as salinity, drought and cold or heat, which are increasingly being observed worldwide in the context of the ongoing climate changes, limit their growth and productivity. Behind the remarkable ability of plants to cope with these stresses and still thrive, sophisticated and efficient mechanisms to re-establish and maintain ion and cellular homeostasis are involved. Among the plant arsenal to maintain homeostasis are efficient stress sensing and signaling mechanisms, plant cell detoxification systems, compatible solute and osmoprotectant accumulation and a vital rearrangement of solute transport and compartmentation. The key role of solute transport systems and signaling proteins in cellular homeostasis is addressed in the present work. The full understanding of the plant cell complex defense mechanisms under stress may allow for the engineering of more tolerant plants or the optimization of cultivation practices to improve yield and productivity, which is crucial at the present time as food resources are progressively scarce.
TL;DR: Direct multisearch (DMS) as discussed by the authors is a direct-search method that does not aggregate any of the objective functions to optimize and uses the concept of Pareto dominance to maintain a list of non-nominated points from which the new iterates or poll centers are chosen.
Abstract: In practical applications of optimization it is common to have several conflicting objective functions to optimize. Frequently, these functions are subject to noise or can be of black-box type, preventing the use of derivative-based techniques. We propose a novel multiobjective derivative-free methodology, calling it direct multisearch (DMS), which does not aggregate any of the objective functions. Our framework is inspired by the search/poll paradigm of direct-search methods of directional type and uses the concept of Pareto dominance to maintain a list of nondominated points (from which the new iterates or poll centers are chosen). The aim of our method is to generate as many points in the Pareto front as possible from the polling procedure itself, while keeping the whole framework general enough to accommodate other disseminating strategies, in particular, when using the (here also) optional search step. DMS generalizes to multiobjective optimization (MOO) all direct-search methods of directional type....
TL;DR: In this article, the authors present an innovative approach for developing building sustainability assessment and rating, and contribute to the evolution of generic methodology and international understanding by introducing an approach which takes the different dimensions of sustainability into account.
TL;DR: In this article, measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at root s = 7 TeV are presented, independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background.
Abstract: Measurements of luminosity obtained using the ATLAS detector during early running of the Large Hadron Collider (LHC) at root s = 7 TeV are presented. The luminosity is independently determined using several detectors and multiple algorithms, each having different acceptances, systematic uncertainties and sensitivity to background. The ratios of the luminosities obtained from these methods are monitored as a function of time and of mu, the average number of inelastic interactions per bunch crossing. Residual time- and mu-dependence between the methods is less than 2% for 0 < mu < 2.5. Absolute luminosity calibrations, performed using beam separation scans, have a common systematic uncertainty of +/- 11%, dominated by the measurement of the LHC beam currents. After calibration, the luminosities obtained from the different methods differ by at most +/- 2%. The visible cross sections measured using the beam scans are compared to predictions obtained with the PYTHIA and PHOJET event generators and the ATLAS detector simulation.
TL;DR: It is found that decisions within small groups under high risk and stringent requirements to success significantly raise the chances of coordinating actions and escaping the tragedy of the commons.
Abstract: From group hunting to global warming, how to deal with collective action may be formulated in terms of a public goods game of cooperation. In most cases, contributions depend on the risk of future losses. Here, we introduce an evolutionary dynamics approach to a broad class of cooperation problems in which attempting to minimize future losses turns the risk of failure into a central issue in individual decisions. We find that decisions within small groups under high risk and stringent requirements to success significantly raise the chances of coordinating actions and escaping the tragedy of the commons. We also offer insights on the scale at which public goods problems of cooperation are best solved. Instead of large-scale endeavors involving most of the population, which as we argue, may be counterproductive to achieve cooperation, the joint combination of local agreements within groups that are small compared with the population at risk is prone to significantly raise the probability of success. In addition, our model predicts that, if one takes into consideration that groups of different sizes are interwoven in complex networks of contacts, the chances for global coordination in an overall cooperating state are further enhanced.
TL;DR: In this paper, the piezoelectric d33 response of montmorillonite clay was measured and the obtained value of d33 is −7 pC/N, lower than in β-PVDF obtained by mechanical stretching but still among the largest coefficients obtained for polymers.
Abstract: Poly(vinylidene fluoride), PVDF, based nanocomposites with different clay structures have been processed by solvent casting and melt crystallization. Depending on the melting temperature of the polymer, the nanocomposite recrystalises in the electroactive γ or nonelectroactive α phase of the polymer. This fact is related to the thermal behavior of the clay. For montmorillonite clay, the full crystallization of the electroactive γ phase occurs for clay contents lower than 0.5 wt %, allowing the nanocomposites to maintain the mechanical properties of the polymer matrix. The electroactivity of the material has been proven by measuring the piezoelectric d33 response of the material. The obtained value of d33 is −7 pC/N, lower than in β-PVDF obtained by mechanical stretching but still among the largest coefficients obtained for polymers. Further, the optical transmittance in the visible range is strongly enhanced with respect to the transmittance of the pure polymer. Finally, it is demonstrated that the nuclea...
TL;DR: In this article, the authors propose a new test that explores the two-way interaction between the magnitude of the opportunistic distortion and the margin of victory, and show that opportunism leads to a larger win-margin for the incumbent.
Abstract: The literature on the rational PBC suggests that politicians systematically manipulate economic and fiscal conditions before elections to increase their chances of reelection. Most tests of this theory look for evidence of pre-election distortions in fiscal policy. We propose a new test that explores the two-way interaction between the magnitude of the opportunistic distortion and the margin of victory. The test is implemented using a large panel of Portuguese municipalities. The results show that opportunism leads to a larger win-margin for the incumbent and that incumbents behave more opportunistically when their win-margin is small. These results are consistent with the theoretical model.
TL;DR: In this paper, the effect of competition on quality in hospital markets with regulated prices was analyzed, considering both introducing competition and increasing competition through either lower transportation costs (increased substitutability) or a higher number of hospitals.
Abstract: We analyse the effect of competition on quality in hospital markets with regulated prices, considering the effect of both introducing competition (monopoly versus competition) and increasing competition through either lower transportation costs (increased substitutability) or a higher number of hospitals. With semi-altruistic providers and a fairly general cost structure, we show that the relationship between competition and quality is generally ambiguous. In contrast to the received body of theoretical literature, this is consistent with, and potentially explains, the mixed empirical evidence.
TL;DR: Recent advances in knowledge of Candida glabrata, Candida parapsilosis and Candida tropicalis virulence factors are discussed, specifically those of adhesion and biofilm formation, which are key components in Candida pathogenicity.
TL;DR: It is observed that the produced GG–MA hydrogels possess improved mechanical properties and lower water uptake ability and degradation rate as compared to gellan gum, and are non‐cytotoxic in vitro, thus being promising biomaterials to be used in IVD tissue‐engineering strategies.
Abstract: Intervertebral disc (IVD) degeneration is a challenging clinical problem that urgently demands viable nucleus pulposus (NP) implant materials. The best suited biomaterial for NP regeneration has yet to be identified, but it is believed that biodegradable hydrogel-based materials are promising candidates. In this work, we have developed ionic- and photo-crosslinked methacrylated gellan gum (GG-MA) hydrogels to be used in acellular and cellular tissue-engineering strategies for the regeneration of IVDs. The physicochemical properties of the developed hydrogels were investigated by Fourier-transform infrared spectroscopy, (1) H nuclear magnetic resonance and differential scanning calorimetry. The swelling ability and degradation rate of hydrogels were also analysed in phosphate-buffered saline solution at physiological pH for a period of 30 days. Additionally, the morphology and mechanical properties of the hydrogels were assessed under a scanning electron microscope and dynamic compression, respectively. An in vitro study was carried out to screen possible cytotoxicity of the gellan gum-based hydrogels by culturing rat lung fibroblasts (L929 cells) with hydrogel leachables up to 7 days. The results demonstrated that gellan gum was successfully methacrylated. We observed that the produced GG-MA hydrogels possess improved mechanical properties and lower water uptake ability and degradation rate as compared to gellan gum. This work also revealed that GG-MA hydrogels are non-cytotoxic in vitro, thus being promising biomaterials to be used in IVD tissue-engineering strategies.
TL;DR: In this paper, the properties of polysaccharide multinanolayer solutions such as zeta potential (Zp) and mean hydrodynamic diameter (Z-average) were analyzed using a 2 3 full factorial design.
TL;DR: In this paper, a combined numerical and experimental study on the dynamic response of a slider-crank mechanism with revolute clearance joints is presented and discussed to provide an experimental verification and validation of the predictive capabilities of the multibody clearance joint models.
Abstract: A comprehensive combined numerical and experimental study on the dynamic response of a slider-crank mechanism with revolute clearance joints is presented and discussed in this paper to provide an experimental verification and validation of the predictive capabilities of the multibody clearance joint models. This study is supported in an experimental work in a test rig, which consists of a slider-crank mechanism with an adjustable radial clearance at the revolute joint between the slider and the connecting rod. The motion of the slider is measured with a linear transducer and an accelerometer. Dynamic tests at different operating crank speeds and with several clearance sizes are performed. The maximum slider acceleration, associated with the impact acceleration, is used as a measure of the impact severity. The obtained results demonstrate the dynamical behavior of a multibody mechanical system with a clearance joint. Finally, the correlation between the numerical and experimental results is presented and discussed leading to validated models of clearance revolute joints.