Brief Discussion (brief + discussion)

Distribution by Scientific Domains


Selected Abstracts


Two Diverticula of the Left Ventricular Outflow Tract Adjacent to the Commissures of a Bicuspid Aortic Valve

CONGENITAL HEART DISEASE, Issue 6 2006
Unni Krishnan MRCP
ABSTRACT We report a rare combination of congenital cardiac malformations in an asymptomatic adult,a bicuspid aortic valve and double fibrous diverticula of the left ventricle. We describe the presentation and course of events followed by a brief discussion of ventricular diverticula and the management of this rare combination of anomalies. [source]


The regulation and function of mammalian AMPK-related kinases

ACTA PHYSIOLOGICA, Issue 1 2009
N. J. Bright
Abstract AMP-activated protein kinase (AMPK) is a key regulator of cellular and whole-body energy homeostasis. Recently, 12 AMPK-related kinases (BRSK1, BRSK2, NUAK1, NUAK2, QIK, QSK, SIK, MARK1, MARK2, MARK3, MARK4 and MELK) were identified that are closely related by sequence homology to the catalytic domain of AMPK. The protein kinase LKB1 acts as a master upstream kinase activating AMPK and 11 of the AMPK-related kinases by phosphorylation of a conserved threonine residue in their T-loop region. Further sequence analyses have identified the eight-member SNRK kinase family as distant relatives of AMPK. However, only one of these is phosphorylated and activated by LKB1. Although much is known about AMPK, many of the AMPK-related kinases remain largely uncharacterized. This review outlines the general similarities in structure and function of the AMPK-related kinases before examining the specific characteristics of each, including a brief discussion of the SNRK family. [source]


Optical imaging of infants' neurocognitive development: Recent advances and perspectives

DEVELOPMENTAL NEUROBIOLOGY, Issue 6 2008
Yasuyo Minagawa-Kawai
Abstract Near-infrared spectroscopy (NIRS) provides a unique method of monitoring infant brain function by measuring the changes in the concentrations of oxygenated and deoxygenated hemoglobin. During the past 10 years, NIRS measurement of the developing brain has rapidly expanded. In this article, a brief discussion of the general principles of NIRS, including its technical advantages and limitations, is followed by a detailed review of the role played so far by NIRS in the study of infant perception and cognition, including language, and visual and auditory functions. Results have highlighted, in particular, the developmental changes of cerebral asymmetry associated with speech acquisition. Finally, suggestions for future studies of neurocognitive development using NIRS are presented. Although NIRS studies of the infant brain have yet to fulfill their potential, a review of the work done so far indicates that NIRS is likely to provide many unique insights in the field of developmental neuroscience. © 2008 Wiley Periodicals, Inc. Develop Neurobiol, 2008 [source]


The diabetic foot: grand overview, epidemiology and pathogenesis

DIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue S1 2008
Andrew J. M. Boulton
Abstract This review assesses the progress that has been made over the last quarter century in our understanding of the pathogenesis of diabetic foot problems as well as in their management. Some recent exciting developments are highlighted. This is followed by a brief discussion on the epidemiology and causal pathways to diabetic foot disease. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Seismic behaviour of self-centring braced frame buildings with reusable hysteretic damping brace

EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 10 2007
Songye Zhu
Abstract This paper presents the seismic behaviour of a concentrically braced frame system with self-centring capability, in which a special type of bracing element termed reusable hysteretic damping brace (RHDB) is used. The RHDB is a passive energy dissipation device with its core energy-dissipating component made of superelastic Nitinol wires. Compared with conventional bracing in steel structures, RHDB has a few prominent performance characteristics: damage free under frequent and design basis earthquakes in earthquake prone areas; minimal residual drifts due to the self-centring capability of RHDB frame; and ability to survive several strong earthquakes without the need for repair or replacement. This paper also includes a brief discussion of the RHDB's mechanical configuration and analytical model for RHDB. The seismic performance study of RHDB frame was carried out through a non-linear time history analysis of 3-storey and 6-storey RHDB frame buildings subjected to two suites of 20 earthquake ground motions. The analysis results were compared with buckling-restrained brace (BRB) frames. This study shows that RHDB frame has a potential to outperform BRB frames by eliminating the residual drift problem. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Mercury speciation by CE: An update

ELECTROPHORESIS, Issue 1 2009
Petr Kubán
Abstract This review provides an update on mercury speciation by CE. It includes a brief discussion on physicochemical properties, toxicity and transformation pathways of mercury species (i.e. methyl-, ethyl-, phenyl- and inorganic mercury) and outlines recent trends in Hg speciation by CE. CE is presented as a complementary technique to chromatographic separation techniques, especially in cases when speed, high efficiency and low sample volumes are required. The development of suitable sample preconcentration/isolation (sample stacking, ion exchange, liquid,liquid,liquid extraction, dual-cloud point extraction) to achieve low LODs for analysis of trace concentrations of mercury species in real samples is emphasized. Hyphenation of CE to element specific detectors (i.e. electrothermal atomic absorption spectrometry, atomic fluorescence spectrometry, inductively coupled plasma-optical emission spectrometry, inductively coupled plasma-mass spectrometry) is discussed as well as a potential of CE in interaction studies that may provide useful information on interaction of various Hg species with selected bio-macromolecules. [source]


Imaging of the shoulder

EQUINE VETERINARY EDUCATION, Issue 4 2010
W. R. Redding
Summary Diagnosis of lameness associated with the shoulder region requires a careful clinical examination, the use of specifically placed intra-articular analgesia and a combination of some common imaging techniques to accurately define the source of pain. Most equine practices performing lameness examinations in the horse have the radiographic and ultrasonographic equipment necessary to accurately image the shoulder. This article presents a description of the unique anatomy of the shoulder and the specific application of radiographic and ultrasonographic techniques to provide a complete set of diagnostic images of the shoulder region. A brief discussion of nuclear scintigraphy of this region is also included. [source]


Models of reproductive skew: A review and synthesis (Invited Article)

ETHOLOGY, Issue 1 2000
Rufus A. Johnstone
Animal societies vary markedly in reproductive skew, the extent to which breeding is monopolised by dominant individuals. In the last few years, a large number of different models have been developed to explain this variation. Here, I review existing models of reproductive skew, distinguishing between two basic types. Transactional models focus on group stability and the constraints this places on the division of reproduction. Compromise models, by contrast, ignore issues of group stability and view the division of reproduction as the outcome of a conflict in which each group member has a limited or partial ability to enforce its own optimum. I go on to show, however, that the division between transactional and compromise models is somewhat artificial, and that both approaches may be combined in a single, synthetic treatment. Different models of reproductive skew are thus better seen as special cases of a general underlying theory, rather than alternative paradigms. I conclude with a brief discussion of the possibilities and problems of empirically testing this unified theory of skew, and the prospects for future theoretical advances. [source]


International issues in the supply of tobacco: recent changes and implications for alcohol

ADDICTION, Issue 12s4 2000
Frank J. Chaloupka
This paper reviews international issues in the supply of tobacco and tobacco products, including trade liberalization and globalization. The paper begins with a brief discussion of the theoretical foundations for trade and trade restrictions. This is followed by a description of the treatment of tobacco and tobacco products in recent multi-lateral, regional and bilateral trade agreements, as well as a short discussion of the recent globalization of the tobacco industry. Included in this description is a review of the empirical evidence on the impact of trade liberalization on tobacco use. The implications of two recently proposed international agreements - the Multilateral Agreement on Investments and the Framework Convention for Tobacco Control - are then discussed. The paper concludes by summarizing the theoretical and empirical evidence that shows clearly that trade liberalization has significantly increased tobacco use, particularly in low and middle-income countries, and follows this with a discussion of the lessons learned from tobacco for controlling alcohol supply. [source]


Targeted Musculoarticular Sonography in the Detection of Joint Effusions

ACADEMIC EMERGENCY MEDICINE, Issue 4 2001
Verena T. Valley MD
Abstract. This article describes an advanced application for an established technology, specifically the use of bedside sonography in the assessment of the acutely painful joint in the emergency department. The sonographic windows for each of the axial synovial joints are outlined, with a brief discussion of commonly encountered pathologic conditions. [source]


Fragrance materials and their environmental impact

FLAVOUR AND FRAGRANCE JOURNAL, Issue 2 2004
Daniel T. Salvito
Abstract A brief discussion on the environmental fate and effects of fragrance materials was recently presented in Cadby et al.1. This paper has been prepared as a more detailed discussion of the environmental effects associated with fragrance materials. Cadby et al.1 presented a detailed discussion of the rigorous science employed to protect the consumer and the environment from adverse effects from these materials. The Research Institute for Fragrance Materials (RIFM) has established a comprehensive environmental research and testing programme to determine the potential environmental risks posed by fragrance materials to the environment. Sponsored research and testing includes ecotoxicological studies, the biotransformation of fragrance materials in wastewater treatment, and their fate in the terrestrial environment. RIFM has published a conservative screening level risk assessment model following established environmental risk assessment paradigms (i.e. the predicted environmental concentration: predicted no effect concentration quotient; the PEC,PNEC ratio).2 In an initial screening of all discrete fragrance materials, using only volume of use and available physical-chemical parameters, 92% of these materials are shown to pose an acceptable environmental risk, i.e. their PEC,PNEC ratio is less than 1. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Quantum phenomena via complex measure: Holomorphic extension

FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 7 2006
Article first published online: 11 MAY 200, S.K. Srinivasan
The complex measure theoretic approach proposed earlier is reviewed and a general version of density matrix as well as conditional density matrix is introduced. The holomorphic extension of the complex measure density (CMD) is identified to be the Wigner distribution function of the conventional quantum mechanical theory. A variety of situations in quantum optical phenomena are discussed within such a holomorphic complex measure theoretic framework. A model of a quantum oscillator in interaction with a bath is analyzed and explicit solution for the CMD of the coordinate as well as the Wigner distribution function is obtained. A brief discussion on the assignment of probability to path history of the test oscillator is provided. [source]


Vector Autoregression (Var) , An Approach to Dynamic analysis of Geographic Processes

GEOGRAFISKA ANNALER SERIES B: HUMAN GEOGRAPHY, Issue 2 2001
Max Lu
Vector autoregression (VAR) is a widely used econometric technique for multivariate time series modelling. This paper shows that with several very attractive features, VAR may also provide a valuable tool for analysing the dynamics among geographic processes and for spatial autoregressive modelling. After a brief discussion of the VAR approach, a VAR model for the dynamics of the US population between 1910 and 1990 is estimated and interpreted to illustrate the techniques. The VAR makes it possible to view the interactions among the four variables used in the model (total population, birth rate, immigration and per capita GNP) more adequately. The paper then discusses recent developments in the VAR methodology such as Bayesian vector autoregression (BVAR), spatial prior for regional modelling and cointegration, as well as the limitations and problems that arise from the application of VARs. [source]


Critical Events and Labour Mobility: Relocations in the Wake of the Ansett Airlines Collapse

GEOGRAPHICAL RESEARCH, Issue 3 2009
SALLY WELLER
Abstract Migration plays an important role in neo-liberal regional adjustment. This paper explores the role of economic shocks in stimulating internal migration within Australia. Drawing on the experiences of retrenched Ansett Airlines employees, it argues that economic crisis impels some households to relocate but traps others in places with restricted employment prospects. For some, the crisis of retrenchment triggers inter-state migration to take up new jobs. For others, it prompts relocation to less expensive housing, often in a geographically proximate location. These opposing responses, which are different outcomes of similar causal processes, exacerbate regional inequalities since they selectively encourage younger skilled workers to enter growing regions. The combination of high housing costs and insecure employment discourages speculative migration. The paper concludes with a brief discussion of the policy implications of these findings. [source]


EU Enlargement, Migration, and Lessons from German Unification

GERMAN ECONOMIC REVIEW, Issue 3 2000
Hans-Werner Sinn
The paper studies the role of international implications after EU enlargement. Based on a formal model with migration costs for both capital and labor, it predicts a two-sided migration from the new to the old EU countries which is later reversed. As the migration pattern chosen by market forces turns out to be efficient, migration should not be artificially reduced by means of legal constraints or subsidies to the new member countries. The paper draws the parallel with German unification and points out the lessons to be learned by Europe. The analysis concludes with a brief discussion of the second-best problem posed by the existence of welfare states in the old member countries. [source]


Health and Safety in the Medieval Monasteries of Britain

HISTORY, Issue 309 2008
JULIE KERR
The arduous nature of monastic life could impact on the monks' physical and mental well-being, causing minor injuries but also fatalities. Back problems might develop from ringing the heavy monastery bells, digestive disorders could result from years of fasting, and those holding important offices invariably suffered from stress and strain. There has been significant discussion of healthcare in the monastery , of disease and illness, the treatment of the sick, the infirmary, and the role of professional practitioners within the monastery. Less consideration has been given to the various hazards that might affect the monks on a daily basis, from the obstacles that caused them to trip and tumble to the injuries and fatalities that could result from natural disasters, outbreaks of fire and faulty repair work. This article seeks to explore more fully the perils and pitfalls that the religious community might face, but includes a brief discussion of the general impact of monastic observance on the monks' well-being, and the spiritual and physical recourse they sought to prevent mishaps and to treat casualties. Analysis centres on the monastic houses of Britain in the high middle ages, but refers to later and continental examples for comparative purposes and where they are likely to be indicative of conditions in Britain in the twelfth and thirteenth centuries. [source]


MOVING BEYOND BIOPOWER: HARDT AND NEGRI'S POST-FOUCAULDIAN SPECULATIVE PHILOSOPHY OF HISTORY

HISTORY AND THEORY, Issue 4 2005
RÉAL FILLION
ABSTRACT I argue in this paper that the attempt by Michael Hardt and Antonio Negri in Empire and Multitude to "theorize empire" should be read both against the backdrop of speculative philosophy of history and as a development of the conception of a "principle of intelligibility" as this is discussed in Michel Foucault's recently published courses at the Collège de France. I also argue that Foucault's work in these courses (and elsewhere) can be read as implicitly providing what I call "prolegomena to any future speculative philosophy of history." I define the latter as concerned with the intelligibility of the historical process considered as a whole. I further suggest, through a brief discussion of the classical figures of Kant, Hegel, and Marx, that the basic features of speculative philosophy of history concern the articulation of both the telos and dynamics of history. My claim is that Hardt and Negri provide an account of the telos and dynamics of history that respects the strictures imposed on speculative philosophy of history by Foucault's work, and thus can be considered as providing a post-Foucauldian speculative philosophy of history. In doing so, they provide a challenge to other "theoretical" attempts to account for our changing world. [source]


Selecting the best and brightest: Leveraging human capital

HUMAN RESOURCE MANAGEMENT, Issue 3 2002
Brian S. O'Leary
This article provides a brief discussion of the changing nature of work and describes how automation and the Internet are changing the way the U.S. government recruits and hires employees. The authors discuss the validity of various assessment methods used to select and promote employees and the return on investment that can result from using valid assessment techniques. The authors review several illustrative assessment programs used in the federal government. Finally, the authors explore the next generation of assessments. © 2002 Wiley Periodicals, Inc. [source]


Multifunctional Composites of Ceramics and Single-Walled Carbon Nanotubes

ADVANCED MATERIALS, Issue 17 2009
Nitin P. Padture
Abstract Polycrystalline ceramic/single-walled carbon nanotube (SWNT) composites possess unique grain boundaries, containing 1D tortuous SWNTs bundles that form 2D tangled embedded nets. This unprecedented grain-boundary structure allows tailoring of multifunctional ceramic/SWNTs composites with unique combinations of desirable mechanical (toughness, strength, creep) and transport (electrical, thermal) properties. A brief discussion and analysis of recent developments in these composites are presented. [source]


Regularized sequentially linear saw-tooth softening model

INTERNATIONAL JOURNAL FOR NUMERICAL AND ANALYTICAL METHODS IN GEOMECHANICS, Issue 7-8 2004
Jan G. Rots
Abstract After a brief discussion on crack models, it is demonstrated that cracking is often accompanied by snaps and jumps in the load,displacement response which complicate the analysis. This paper provides a solution by simplifying non-linear crack models into sequentially linear saw-tooth models, either saw-tooth tension-softening for unreinforced material or saw-tooth tension-stiffening for reinforced material. A linear analysis is performed, the most critical element is traced, the stiffness and strength of that element are reduced according to the saw-tooth curve, and the process is repeated. This approach circumvents the use of incremental,iterative procedures and negative stiffness moduli and is inherently stable. The main part of the paper is devoted to a regularization procedure that provides mesh-size objectivity of the saw-tooth model. The procedure is similar to the one commonly used in the smeared crack framework but, in addition, both the initial tensile strength and the ultimate strain are rescaled. In this way, the dissipated fracture energy is invariant with respect not only to the mesh size, but also to the number of saw-teeth adopted to discretize the softening branch. Finally, the potential of the model for large-scale fracture analysis is demonstrated. A masonry façade subjected to tunnelling induced settlements is analysed. The very sharp snap-backs associated with brittle fracture of the façade automatically emerge with sequentially linear analysis, whereas non-linear analysis of the façade using smeared or discrete crack models shows substantial difficulties despite the use of arc-length schemes. Copyright © 2004 John Wiley & Sons, Ltd. [source]


Three-dimensional Mohr,Coulomb limit analysis using semidefinite programming

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2008
K. Krabbenhøft
Abstract Recently, Krabbenhøft et al. (Int. J. Solids Struct. 2007; 44:1533,1549) have presented a formulation of the three-dimensional Mohr,Coulomb criterion in terms of positive-definite cones. The capabilities of this formulation when applied to large-scale three-dimensional problems of limit analysis are investigated. Following a brief discussion on a number of theoretical and algorithmic issues, three common, but traditionally difficult, geomechanics problems are solved and the performance of a common primal,dual interior-point algorithm (SeDuMi (Appl. Numer. Math. 1999; 29:301,315)) is documented in detail. Although generally encouraging, the results also reveal several difficulties which support the idea of constructing a conic programming algorithm specifically dedicated to plasticity problems. Copyright © 2007 John Wiley & Sons, Ltd. [source]


Construction of shape functions for the h - and p -versions of the FEM using tensorial product

INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN ENGINEERING, Issue 5 2007
M. L. Bittencourt
Abstract This paper presents an uniform and unified approach to construct h - and p -shape functions for quadrilaterals, triangles, hexahedral and tetrahedral based on the tensorial product of one-dimensional Lagrange and Jacobi polynomials. The approach uses indices to denote the one-dimensional polynomials in each tensorization direction. The appropriate manipulation of the indices allows to obtain hierarchical or non-hierarchical and inter-element C0 continuous or non-continuous bases. For the one-dimensional elements, quadrilaterals, triangles and hexahedral, the optimal weights of the Jacobi polynomials are determined, the sparsity profiles of the local mass and stiffness matrices plotted and the condition numbers calculated. A brief discussion of the use of sum factorization and computational implementation is considered. Copyright © 2006 John Wiley & Sons, Ltd. [source]


Halitosis among racially diverse populations: an update

INTERNATIONAL JOURNAL OF DENTAL HYGIENE, Issue 1 2008
S Rayman
Abstract:, The aim of this paper is to highlight the cultural perceptions of halitosis to dental professionals. Halitosis (oral malodour or bad breath) is caused mainly by tongue coating and periodontal disease. Bacterial metabolism of amino acids leads to metabolites including many compounds, such as indole, skatole and volatile sulphur compounds (VSC), hydrogen sulphide, methyl mercaptan and dimethyl sulphide. They are claimed to be the main aetiological agents for halitosis. Gastrointestinal diseases are also generally believed to cause halitosis. In general, physicians and dentists are poorly informed about the causes and treatments for halitosis. The paper reviews the prevalence and distribution of halitosis, oral malodour, its aetiology, concepts of general and oral health and diseases and their perception among racially diverse population. Eating, smoking and drinking habits and understanding of halitosis as a social norm among different people has been highlighted. The treatment options have also been presented very briefly. A brief discussion about general importance within existing healthcare services has been highlighted. Oral malodour may rank only behind dental caries and periodontal disease as the cause of patient's visits to the dentist. It is a public social health problem. The perception of halitosis is different in culturally diverse populations. So the dental professionals should be aware of the cultural perceptions of halitosis among racially and culturally diverse populations. There is a need to integrate the cultural awareness and knowledge about halitosis among the dental professional for better understanding of halitosis to treat patients with the social dilemma of halitosis to improve the quality of life and well-being of individuals with the problem. It is concluded that dental professionals (especially dental hygienists) should be prepared to practice in a culturally diverse environment in a sensitive and appropriate manner, to deliver optimal oral health and hygiene care. [source]


Regioselective Reactions on a Chiral Substrate Controlled by the Configuration of a Chiral Catalyst

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 2-3 2010
Raju Ranjith Kumar
Abstract A racemic mixture may be partially transformed in the presence of a chiral catalyst by kinetic resolution and formation of products with new structural features. If the starting material is fully consumed the products may still be enantiomerically enriched. The situation is summarized in the Introduction. A brief discussion on the regioselective transformations occurring on a racemic mixture under the influence of a chiral catalyst is presented in Section 2. Often stereo-differences occur, each enantiomer of the starting material resulting in a different product. It allows one to predict what the behaviour of some enantiopure substrates should be in presence of each of the enantiomers of a chiral catalyst. Many examples are presented in Section 3. The chiral substrates under consideration have two different reacting sites, usually of the same nature (OH, CC, allylic positions, CH for carbene insertion, epoxide fragment, etc.). In some cases the absolute configuration of the catalyst allows an excellent control of the regioselectivity. This approach is promising for the selective transformation of chiral molecules. [source]


Quantum statistics of charged particles and fingerprints of wigner crystallization in D dimensions

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 15 2006
N. H. March
Abstract After a brief summary of the physical arguments underlying Wigner's original concept in 1934 of a quantal electron crystal, theoretical interpretation of a number of experimental findings are presented. These include (i) low-density carriers in semiconductors in applied magnetic fields in both three, and recently two, dimensions; and (ii) low-temperature phase diagram of underdoped high Tc cuprates; fullerides with relatively low Tc are also referred to in a related context. Interpretation of areas (i) and (ii) focuses on the relevance of both Fermi,Dirac and anyonic (fractional) statistics, the latter in relation to the proposed melting curve of the two-dimensional (2D) magnetically induced Wigner solid into the Laughlin liquid phase, which is the seat of the fractional quantum Hall effect. A brief discussion follows of crystalline phases additional to the Wigner solid, namely Skyrmion and Hall crystals. Bose,Einstein statistics is then referred to, but now in relation to finite-size confined quantal assemblies, with fingerprints of Wigner molecules the focus. Finally, quasi-1D lattices are considered, both in Bechgaard salts and in the very recent single-electron counting experiment of Bylander et al. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source]


Synthetic Applications of Laccase in Green Chemistry

ADVANCED SYNTHESIS & CATALYSIS (PREVIOUSLY: JOURNAL FUER PRAKTISCHE CHEMIE), Issue 9 2009
Suteera Witayakran
Abstract Laccases (benzenediol:oxygen oxidoreductase, EC 1.10.3.2), multi-copper-containing oxidoreductase enzymes, are able to catalyze the oxidation of various low-molecular weight compounds, specifically, phenols and anilines, while concomitantly reducing molecular oxygen to water. Because of their high stability, selectivity for phenolic substructures, and mild reaction conditions, laccases are attractive for fine chemical synthesis. This review provides a discussion of the recent applications of this interesting enzyme in synthetic chemistry, including laccase and laccase-mediator catalyzed reactions. In addition, the review also includes a brief discussion of the distribution of laccase in nature, enzyme structure, and the catalytic mechanism which are of relevance to their applications as biocatalysts. [source]


Solitude: An Exploration of Benefits of Being Alone

JOURNAL FOR THE THEORY OF SOCIAL BEHAVIOUR, Issue 1 2003
Christopher R. Long
Christopher R. Long and James R. Averill, Solitude: An Exploration of Benefits of Being Alone, pp. 21,44. Historically, philosophers, artists, and spiritual leaders have extolled the benefits of solitude; currently, advice on how to achieve solitude is the subject of many popular books and articles. Seldom, however, has solitude been studied by psychologists, who have focused instead on the negative experiences associated with being alone, particularly loneliness. Solitude, in contrast to loneliness, is often a positive state,one that may be sought rather than avoided. In this article, we examine some of the benefits that have been attributed to solitude,namely, freedom, creativity, intimacy, and spirituality. In subsequent sections, we consider the environmental settings and personality characteristics conducive to solitude, how time spent alone is experienced differently across the life span, and the potential dangers related to the attractiveness of solitude. We conclude with a brief discussion of the theoretical and practical implications of solitude. [source]


Anatomy of a crisis: the causes and consequences of surging food prices

AGRICULTURAL ECONOMICS, Issue 2008
Derek Headey
Agricultural policy; Commodity markets; Biofuels Abstract Although the potential causes and consequences of recent rising international food prices have attracted widespread attention, many existing appraisals are superficial and/or piecemeal. This article attempts to provide a more comprehensive review of these issues based on the best and most recent research, as well as on fresh theoretical and empirical analysis. We first analyze the causes of the current crisis by considering how well standard explanations hold up against relevant economic theory and important stylized facts. Some explanations turn out to hold up much better than others, especially rising oil prices, the depreciation of the U.S. dollar, biofuels demand, and some commodity-specific explanations. We then provide an appraisal of the likely macro- and microeconomic impacts of the crisis on developing countries. We observe a large gap between macro and micro factors, which, when identifying the most vulnerable countries, often point in different directions. We conclude with a brief discussion of what ought to be learned from this crisis. [source]


Foreign exchange pressures in Latin America: Does debt matter?

JOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 5 2008
Alex Mandilaras
Abstract Latin American countries have been in the eye of economic and financial storms several times in recent years. Advice from the International Monetary Fund has consistently highlighted the need for sound fiscal policies and lower debt levels. But is public debt relevant? Following a brief discussion of the theoretical issues involved, this paper examines empirically the relationship between public indebtedness and pressures in the foreign exchange market. Alternative measures are used to capture the latter and the analysis controls for a de facto classification of exchange rate regimes. Estimations of static and dynamic panels for 28 Latin American and Caribbean (LAC) countries report substantial fiscal effects. Copyright © 2008 John Wiley & Sons, Ltd. [source]


Tau oligomers and aggregation in Alzheimer's disease

JOURNAL OF NEUROCHEMISTRY, Issue 6 2010
Marco A. Meraz-Ríos
J. Neurochem. (2010) 112, 1353,1367. Abstract We are analyzing the physiological function of Tau protein and its abnormal pathological behavior when this protein is self-assemble into pathological filaments. These aggregates of Tau protein are the main components in many diseases such as Alzheimer's disease (AD). Recent studies suggest that Tau acquires complex oligomeric conformations which may be toxic. In this review, we emphasized the possible phenomena implicated in the formation of these oligomers. Studies with chemical inductors indicates that the microtubule-binding domain is the most important region involved in Tau aggregation and showed the requirement of a pre-arrange Tau in abnormal conformation to promote self-assembly. Transgenic animal models and AD neuropathology studies showed that post-translational modifications are also implicated in Tau aggregation and neural cell death during AD development. Therefore, we analyzed some events that could be present during Tau aggregation. Finally, we included a brief discussion of the possible relation between glucose metabolism dysfunction in AD, and data of Tau aggregation by using aggregation inhibitors. In conclusion, the process Tau aggregation deserves further investigations to design possible therapeutic targets to inhibit the toxicity of these aggregates and it is possible that could be extended to other diseases with similar etiology. [source]