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Selected AbstractsClinical presentations of alopecia areataDERMATOLOGIC THERAPY, Issue 4 2001Maria K. Hordinsky Alopecia areata (AA) may can occur on any hair-bearing region. Patients can develop patchy nonscarring hair loss or extensive loss of all body hair. Hair loss may fluctuate. Some patients experience recurrent hair loss followed by hair regrowth, whereas others may only develop a single patch of hair loss, never to see the disease again. Still others experience extensive loss of body hair. The heterogeneity of clinical presentations has led investigators conducting clinical therapeutic trials to typically group patients into three major groups, those with extensive scalp hair loss [alopecia totalis (AT)], extensive body hair loss [alopecia universalis (AU)], or patchy disease (AA). Treatment outcomes have been correlated with disease duration and extent. Recently, guidelines were established for selecting and assessing subjects for both clinical and laboratory studies of AA, thereby facilitating collaboration, comparison of data, and the sharing of patient-derived tissue. For reporting purposes the terms AT and AU, though still used are defined very narrowly. AT is 100% terminal scalp hair loss without any body hair loss and AU is 100% terminal scalp hair and body loss. AT/AU is the term now recommended to define the presence of AT with variable amounts of body hair loss. In this report the term AA will be used broadly to encompass the many presentations of this disease. Development of AA may occur with changes in other ectodermal-derived structures such as fingernails and toenails. Some investigators have also suggested that other ectodermal-derived appendages as sebaceous glands and sweat glands may be affected in patients experiencing AA. Whether or not function of these glands is truly impaired remains to be confirmed. Many patients who develop patchy or extensive AA complain of changes in cutaneous sensation, that is, burning, itching, tingling, with the development of their disease. Similar symptoms may occur with hair regrowth. The potential involvement of the nervous system in AA has led to morphologic investigations of the peripheral nervous system as well as analysis of circulating neuropeptide levels. In this article the clinical presentations of AA are reviewed. The guidelines for conducting treatment studies of AA are presented and observations on changes in cutaneous innervation are introduced. Throughout the text, unless otherwise noted, AA will be used in a general way to denote the spectrum of this disease. [source] The implicit assumption of symmetry and the species abundance distributionECOLOGY LETTERS, Issue 2 2008David Alonso Abstract Species abundance distributions (SADs) have played a historical role in the development of community ecology. They summarize information about the number and the relative abundance of the species encountered in a sample from a given community. For years ecologists have developed theory to characterize species abundance patterns, and the study of these patterns has received special attention in recent years. In particular, ecologists have developed statistical sampling theories to predict the SAD expected in a sample taken from a region. Here, we emphasize an important limitation of all current sampling theories: they ignore species identity. We present an alternative formulation of statistical sampling theory that incorporates species asymmetries in sampling and dynamics, and relate, in a general way, the community-level SAD to the distribution of population abundances of the species integrating the community. We illustrate the theory on a stochastic community model that can accommodate species asymmetry. Finally, we discuss the potentially important role of species asymmetries in shaping recently observed multi-humped SADs and in comparisons of the relative success of niche and neutral theories at predicting SADs. [source] Structural Equations, Treatment Effects, and Econometric Policy Evaluation1ECONOMETRICA, Issue 3 2005James J. Heckman This paper uses the marginal treatment effect (MTE) to unify the nonparametric literature on treatment effects with the econometric literature on structural estimation using a nonparametric analog of a policy invariant parameter; to generate a variety of treatment effects from a common semiparametric functional form; to organize the literature on alternative estimators; and to explore what policy questions commonly used estimators in the treatment effect literature answer. A fundamental asymmetry intrinsic to the method of instrumental variables (IV) is noted. Recent advances in IV estimation allow for heterogeneity in responses but not in choices, and the method breaks down when both choice and response equations are heterogeneous in a general way. [source] The Interdependence of U.S. Troop Deployments and Trade in the Developing WorldFOREIGN POLICY ANALYSIS, Issue 3 2009Glen Biglaiser The relationship between political conflict and trade has contributed to a riveting discussion in international relations about whether trade produces conflict, or whether conflict itself reduces trade. Most studies proxy "the flag" using militarized interstate disputes (MIDs). However, extensions of "the flag" might well obtain in environments short of MIDs. A more general way to proxy the flag is troop deployments. The deployment of military troops is an essential element of foreign policy. Using panel data for 126 developing countries from 1965 to 2002 and a two-stage least square approach, this essay investigates the relationship between trade and United States troop deployments. We find that trade and troops have a nonrecursive relationship: trade follows the flag and troops follow trade. Given the increased insecurity in the world today, the results are timely and reinforce previous research about the reciprocal relationship between the flag and trade. [source] Locational Equilibria in Weberian AgglomerationGEOGRAPHICAL ANALYSIS, Issue 4 2008Dean M. Hanink A simple Weberian agglomeration is developed and then extended as an innovative fixed-charged, colocation model over a large set of locational possibilities. The model is applied to cases in which external economies (EE) arise due to colocation alone and also cases in which EE arise due to city size. Solutions to the model are interpreted in the context of contemporary equilibrium analysis, which allows Weberian agglomeration to be interpreted in a more general way than in previous analyses. Within that context, the Nash points and Pareto efficient points in the location patterns derived in the model are shown to rarely coincide. The applications consider agglomeration from two perspectives: one is the colocation behavior of producers as the agents of agglomeration and the other is the interaction between government and those agents in the interest of agglomeration policy. Extending the analysis to games, potential Pareto efficiency and Hicks optimality are considered with respect to side payments between producers and with respect to appropriate government incentives toward agglomeration. [source] Symmetric Galerkin BEM for multi-connected bodiesINTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING, Issue 11 2001J. J. Pérez-Gavilán In this paper, it is shown that the symmetric Galerkin boundary element formulation cannot be used in its standard form for multiple connected bodies. This is because the traction integral equation used for boundaries with Neuman boundary condition give non-unique solutions. While this fact is well known from the classical theory of integral equations, the problem has not been fully addressed in the literature related to symmetric Galerkin formulations. In this paper, the problem is reviewed and a general way to deal with it is proposed. The details of the numerical implementation are discussed and an example is solved to demonstrate the effectiveness of the proposed solution. Copyright © 2001 John Wiley & Sons, Ltd. [source] Capturing pressure-dependence in automated mechanism generation: Reactions through cycloalkyl intermediatesINTERNATIONAL JOURNAL OF CHEMICAL KINETICS, Issue 3 2003David M. Matheu Chemical kinetic mechanisms for gas-phase processes (including combustion, pyrolysis, partial oxidation, or the atmospheric oxidation of organics) will often contain hundreds of species and thousands of reactions. The size and complexity of such models, and the need to ensure that important pathways are not left out, have inspired the use of computer tools to generate such large chemical mechanisms automatically. But the models produced by existing computerized mechanism generation codes, as well as a great many large mechanisms generated by hand, do not include pressure-dependence in a general way. This is due to the difficulty of computing the large number of k(T, P) estimates required. Here we present a fast, automated method for computing k(T, P) on-the-fly during automated mechanism generation. It uses as its principal inputs the same high-pressure-limit rate estimation rules and group-additivity thermochemistry estimates employed by existing computerized mechanism-generation codes, and automatically identifies the important chemically activated intermediates and pathways. We demonstrate the usefulness of this approach on a series of pressure-dependent reactions through cycloalkyl radical intermediates, including systems with over 90 isomers and 200 accessible product channels. We test the accuracy of these computer-generated k(T, P) estimates against experimental data on the systems H + cyclobutene, H + cyclopentene, H + cyclohexene, C2H3 + C2H4, and C3H5 + C2H4, and make predictions for temperatures and pressures where no experimental data are available. © 2002 Wiley Periodicals, Inc. Int J Chem Kinet 35: 95,119, 2003 [source] Historical biogeography of Southeast Asia and the West Pacific, or the generality of unrooted area networks as historical biogeographic hypothesesJOURNAL OF BIOGEOGRAPHY, Issue 2 2003Peter C. van Welzen Abstract Aim Unrooted area networks are perhaps a general way in which different historical biogeographical patterns may be combined. Location Southeast Asia up to the West Pacific, Australia, South America. Methods Unrooted area networks based on Primary Brooks Parsimony Analysis of different data sets of Southeast Asian,West Pacific, Australian and South American clades. Results A large Brooks Parsimony historical (cladistic) biogeographic analysis of Southeast Asia and the West Pacific gave a meaningful result when all clades (representing different historical biogeographic patterns) were united into one matrix and an unrooted area network was produced. This network showed geographically adjacent areas as neighbours, which is interpreted as clades dispersing and speciating as soon as areas rafted towards each other. This pseudo-vicariance mechanism, together with the very limited, mainly linear dispersal possibilities, a few large, widespread clades with many endemic species, and the large overlap in distributions displayed by different patterns, may explain the peculiar result. When applied to examples from other areas (bird data from Australia and South America), unrooted area networks for all data perform very poorly. Main conclusions Unrooted historical general area networks are not universally applicable. In general, it is better to split historical patterns a priori and analyse them separately. [source] Attribution and other problems in assessing the returns to agricultural R&DAGRICULTURAL ECONOMICS, Issue 2-3 2001Julian M. Alston Abstract Estimated rates of return to research are distorted by problems of attributing the credit for particular research results, or for particular research-induced productivity increases, among research expenditures undertaken at different times, in different places, and by different agencies. A comprehensive assessment of the evidence from past economic evaluations of the returns to agricultural R&D indicates that studies generally report high rates of return, with enormous variation among studies, but that much of this evidence has been tainted by inadequate attention to attribution problems. This paper raises these concerns in a general way and illustrates their importance with reference to two particular types of attribution problem. First, we consider the problem of accounting for locational spillovers in attributing varietal-improvement technology among research performers, using US wheat varieties as an example. Second, we consider the temporal aspects of the attribution problem using the specification of research lags in econometric models to illustrate the problem of attributing aggregate productivity gains to research expenditures made at different times. [source] Investment under economic and implementation uncertaintyR & D MANAGEMENT, Issue 2 2001Andrianos E. Tsekrekos Some investment decisions are exposed to uncertainty over their implementation phase apart from the underlying economic uncertainty. We provide a general way of introducing implementation uncertainty, which includes prior research as a special case. The generality of our treatment stems from the fact that implementation uncertainty is allowed to affect both the level and the timing of project profitability. In a case explicitly addressed, implementation uncertainty might even cause earlier investment if the probability of uncertainty resolution exceeds the opportunity cost of delaying investment. Investment will be earlier, the higher the effect of uncertainty resolution on project profitability. [source] How integrating industrial design in the product development process impacts on company performanceTHE JOURNAL OF PRODUCT INNOVATION MANAGEMENT, Issue 1 2001Gerda Gemser There is a growing belief that investing in industrial design is beneficial to company performance. This article sheds more light on how and when integrating industrial design in the product development process can enhance a company's competitive position. The basic premise is that the impact of industrial design on company performance is not unconditional, but dependent on industry evolution and design strategy. We opted to define industrial design in a general way, namely as the activity that transforms a set of product requirements into a configuration of materials, elements and components. This activity can have an impact on a product's appearance, user friendliness, ease of manufacture, efficient use of materials, functional performance, and so on. The empirical data incorporated in this study stems from two Dutch manufacturing industries, namely home furniture and precision instruments. Home furniture and precision instruments were selected because the strategy of integrating industrial design in the product development process is rather mature in the first-named industry and emerging in the second. We collected data from firms investing considerably in industrial design (n = 23) and firms investing little to nothing in industrial design (n = 24), using a semistructured questionnaire that was administrated during face-to-face sessions with senior managers. Two out of the three research hypotheses were supported. It was found that the extent to which firms integrate industrial design in new product development projects has a significant and positive influence on company performance (Hla), in particular when the strategy of investing in industrial design is relatively new for the industry involved (Hlb). There was no systematic pattern indicating that design innovation is more important in industries where the use of design is mature than in industries where the use of design is emerging (H2). Instead, we found that design innovation has significant positive performance effects in both types of industries. One important managerial inference from our study is that new product development managers should consider the changing nature of competition during industry evolution while developing strategies that encompass the use of industrial design in new product development. Another important managerial inference is that, besides being innovative in the field of products, being innovative with respect to design and design strategy can help to enhance competitiveness regardless of industry evolution. [source] Civil Society and Democratically Accountable Global GovernanceGOVERNMENT AND OPPOSITION, Issue 2 2004Jan Aart Scholte This article explores the ways and extents that civil society associations can bring greater public accountability to global governance. The analysis first reviews the growth of civil society engagement of global governance. Second, the article elaborates four general ways that civil society associations have promoted increased accountability in global governance: by increasing the public transparency of global governance operations; by monitoring and reviewing global policies; by seeking redress for mistakes and harms attributable to global regulatory bodies; and by advancing the creation of formal accountability mechanisms for global governance. Third, the article identifies six broad circumstances that have affected (and often limited) the extent of civil society achievements with respect to accountability in global governance. [source] Migraine and Psychiatric Comorbidity: From Theory and Hypotheses to Clinical ApplicationHEADACHE, Issue 9 2002Fred D. Sheftell MD Objective.,To review psychiatric issues that accompany migraine and means of addressing these issues. Background.,Psychiatric factors and migraine may interact in three general ways, etiologically, psychophysiologically or biobehaviorally, and comorbidly (the two disorders coexist), which is the present focus. There are several possible mechanisms of comorbidity. The relation between two disorders may be a result of chance. One disorder can cause another disorder: Diabetes can cause diabetic neuropathy. There might be shared environmental risks: Head trauma can cause both posttraumatic epilepsy and posttraumatic headache. And there may be environmental or genetic risk factors that produce a brain state giving rise to both conditions, that is, there may be some common biology underlying both conditions. This last mechanism seems to be the most likely one underlying comorbidity of migraine and psychiatric disorders. We introduce a possible role for classical paradigms of learned helplessness in regard to psychiatric comorbid depressive and anxiety disorders and migraine. Results.,There appears to be an association between migraine and affective disorders, particularly depression and anxiety. There are a number of formal tools for recognizing depression, but clinical evaluation should not be overlooked. Once diagnosed, depression and anxiety should be treated, both to improve the success of migraine treatment and to improve the patient's quality of life. Patients with recurring headaches are much more likely to overuse and misuse, rather than abuse, pain medications. It is important to be alert for signs that the patient may be misusing medication. Behavioral approaches can surround and support pharmacological therapy. Conclusions.,Migraine is often comorbid with psychiatric disorders, particularly depression and anxiety. The relationship is likely based on shared mechanisms and successful treatment is possible. [source] Habitual use of the primate forelimb is reflected in the material properties of subchondral bone in the distal radiusJOURNAL OF ANATOMY, Issue 6 2006Kristian J. Carlson Abstract Bone mineral density is directly proportional to compressive strength, which affords an opportunity to estimate in vivo joint load history from the subchondral cortical plate of articular surfaces in isolated skeletal elements. Subchondral bone experiencing greater compressive loads should be of relatively greater density than subchondral bone experiencing less compressive loading. Distribution of the densest areas, either concentrated or diffuse, also may be influenced by the extent of habitual compressive loading. We evaluated subchondral bone in the distal radius of several primates whose locomotion could be characterized in one of three general ways (quadrupedal, suspensory or bipedal), each exemplifying a different manner of habitual forelimb loading (i.e. compression, tension or non-weight-bearing, respectively). We employed computed tomography osteoabsorptiometry (CT-OAM) to acquire optical densities from which false-colour maps were constructed. The false-colour maps were used to evaluate patterns in subchondral density (i.e. apparent density). Suspensory apes and bipedal humans had both smaller percentage areas and less well-defined concentrations of regions of high apparent density relative to quadrupedal primates. Quadrupedal primates exhibited a positive allometric effect of articular surface size on high-density area, whereas suspensory primates exhibited an isometric effect and bipedal humans exhibited no significant relationship between the two. A significant difference between groups characterized by predominantly compressive forelimb loading regimes vs. tensile or non-weight-bearing regimes indicates that subchondral apparent density in the distal radial articular surface distinguishes modes of habitually supporting of body mass. [source] Religious Belief and the Epistemology of DisagreementPHILOSOPHY COMPASS (ELECTRONIC), Issue 8 2010Michael Thune Consider two people who disagree about some important claim (e.g. the future moral and political consequences of current U.S. economic policy are X). They each believe the other person is in possession of relevant evidence, is roughly equally competent to evaluate that evidence, etc. From the epistemic point of view, how should such recognized disagreement affect their doxastic attitude toward the original claim? Recent research on the epistemology of disagreement has converged upon three general ways of answering this question. The focus of this article is twofold: first, we summarize and give a brief evaluation of the main accounts of the epistemic significance of disagreement; then, we look at what these accounts suggest about how to epistemically assess both inter-religious and intra-religious disagreements. A final section offers recommendations for further research. [source] | |||||||||||||||||||