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Propensity
Kinds of Propensity Terms modified by Propensity Selected AbstractsTHE INTERACTION OF ANTISOCIAL PROPENSITY AND LIFE-COURSE VARYING PREDICTORS OF DELINQUENT BEHAVIOR: DIFFERENCES BY METHOD OF ESTIMATION AND IMPLICATIONS FOR THEORY,CRIMINOLOGY, Issue 2 2007GRAHAM C. OUSEY Recent criminological research has explored the extent to which stable propensity and life-course perspectives may be integrated to provide a more comprehensive explanation of variation in individual criminal offending. One line of these integrative efforts focuses on the ways that stable individual characteristics may interact with, or modify, the effects of life-course varying social factors. Given their consistency with the long-standing view that person,environment interactions contribute to variation in human social behavior, these theoretical integration attempts have great intuitive appeal. However, a review of past criminological research suggests that conceptual and empirical complexities have, so far, somewhat dampened the development of a coherent theoretical understanding of the nature of interaction effects between stable individual antisocial propensity and time-varying social variables. In this study, we outline and empirically assess several of the sometimes conflicting hypotheses regarding the ways that antisocial propensity moderates the influence of time-varying social factors on delinquent offending. Unlike some prior studies, however, we explicitly measure the interactive effects of stable antisocial propensity and time-varying measures of selected social variables on changes in delinquent offending. In addition, drawing on recent research that suggests that the relative ubiquity of interaction effects in past studies may be partly from the poorly suited application of linear statistical models to delinquency data, we alternatively test our interaction hypotheses using least-squares and tobit estimation frameworks. Our findings suggest that method of estimation matters, with interaction effects appearing readily in the former but not in the latter. The implications of these findings for future conceptual and empirical work on stable propensity/time-varying social variable interaction effects are discussed. [source] THE CONTEXT OF MARRIAGE AND CRIME: GENDER, THE PROPENSITY TO MARRY, AND OFFENDING IN EARLY ADULTHOOD,CRIMINOLOGY, Issue 1 2007RYAN D. KING Marriage is central to theoretical debates over stability and change in criminal offending over the life course. Yet, unlike other social ties such as employment, marriage is distinct in that it cannot be randomly assigned in survey research to more definitively assess causal effects of marriage on offending. As a result, key questions remain as to whether different individual propensities toward marriage shape its salience as a deterrent institution. Building on these issues, the current research has three objectives. First, we use a propensity score matching approach to estimate causal effects of marriage on crime in early adulthood. Second, we assess sex differences in the effects of marriage on offending. Although both marriage and offending are highly gendered phenomena, prior work typically focuses on males. Third, we examine whether one's propensity to marry conditions the deterrent capacity of marriage. Results show that marriage suppresses offending for males, even when accounting for their likelihood to marry. Furthermore, males who are least likely to marry seem to benefit most from this institution. The influence of marriage on crime is less robust for females, where marriage reduces crime only for those with moderate propensities to marry. We discuss these findings in the context of recent debates concerning gender, criminal offending, and the life course. [source] THE EFFECTS OF SOCIAL TIES ON CRIME VARY BY CRIMINAL PROPENSITY: A LIFE-COURSE MODEL OF INTERDEPENDENCE,CRIMINOLOGY, Issue 2 2001BRADLEY R. ENTNER WRIGHT Previous studies have explained the transition from criminal propensity in youth to criminal behavior in adulthood with hypotheses of enduring criminal propensity, unique social causation, and cumulative social disadvantage. In this article we develop an additional hypothesis derived from the life-course concept of interdependence: The effects of social ties on crime vary as a function of individuals' propsensity for crime. We tested these four hypotheses with data from the Dunedin Study. In support of life-course interdependence, prosocial ties, such as education, employment, family ties, and partnerships, deterred crime, and antisocial ties, such as delinquent peers, promoted crime, most strongly among low self-control individuals. Our findings bear implications for theories and policies of crime. [source] DISAPPEARING DIVIDENDS: CHANGING FIRM CHARACTERISTICS OR LOWER PROPENSITY TO PAY?JOURNAL OF APPLIED CORPORATE FINANCE, Issue 1 2001Eugene F. Fama The proportion of U.S. firms paying dividends drops sharply during the 1980s and 1990s. Among NYSE, AMEX, and Nasdaq firms, the proportion of dividend payers falls from 66.5% in 1978 to only 20.8% in 1999. The decline is due in part to an avalanche of new listings that tilts the population of publicly traded firms toward small firms with low profitability and strong growth opportunities,the timeworn characteristics of firms that typically do not pay dividends. But this is not the whole story. The authors' more striking finding is that, no matter what their characteristics, firms in general have become less likely to pay dividends. The authors use two different methods to disentangle the effects of changing firm characteristics and changing propensity to pay on the percent of dividend payers. They find that, of the total decline in the proportion of dividend payers since 1978, roughly one-third is due to the changing characteristics of publicly traded firms and two-thirds is due to a reduced propensity to pay dividends. This lower propensity to pay is quite general,dividends have become less common among even large, profitable firms. Share repurchases jump in the 1980s, and the authors investigate whether repurchases contribute to the declining incidence of dividend payments. It turns out that repurchases are mainly the province of dividend payers, thus leaving the decline in the percent of payers largely unexplained. Instead, the primary effect of repurchases is to increase the already high payouts of cash dividend payers. [source] ORIGINAL ARTICLE: Propensity of marine reserves to reduce the evolutionary effects of fishing in a migratory speciesEVOLUTIONARY APPLICATIONS (ELECTRONIC), Issue 3 2009Erin S. Dunlop Abstract Evolutionary effects of fishing can have unwanted consequences diminishing a fishery's value and sustainability. Reserves, or no-take areas, have been proposed as a management tool for reducing fisheries-induced selection, but their effectiveness for migratory species has remained unexplored. Here we develop an eco-genetic model to predict the effects of marine reserves on fisheries-induced evolution under migration. To represent a stock that undergoes an annual migration between feeding and spawning grounds, we draw model parameters from Atlantic cod (Gadus morhua) in the northern part of its range. Our analysis leads to the following conclusions: (i) a reserve in a stock's feeding grounds, protecting immature and mature fish alike, reduces fisheries-induced evolution, even though protected and unprotected population components mix on the spawning grounds; (ii) in contrast, a reserve in a stock's spawning grounds, protecting only mature fish, has little mitigating effects on fisheries-induced evolution and can sometimes even exacerbate its magnitude; (iii) evolutionary changes that are already underway may be difficult to reverse with a reserve; (iv) directly after a reserve is created or enlarged, most reserve scenarios result in yield losses; and (v) timescale is very important: short-term yield losses immediately after a reserve's creation can give way to long-term gains. [source] The Onset of Health Problems and the Propensity of Workers to Change Employers and OccupationsGROWTH AND CHANGE, Issue 3 2003Jodi Messer Pelkowski Although many studies have investigated how poor health affects hours of work and labor force participation, few have examined the extent to which individuals adapt in order to remain in the labor market. Individuals experiencing health problems may move to different types of work in order to remain in the labor force or to reduce the negative labor market consequences of illness. This paper investigates the movement between employers, and among occupation categories when changing employers, using data from the Health and Retirement Study (HRS). One advantage of the HRS is that its questions on life-cycle employment and health patterns permit a long-term perspective on job mobility that is unavailable in most other datasets. Workers with health problems are more likely than healthy workers to remain with their current employer than to switch employers. But among those who switch employers, those with health problems are more likely to change broad occupational categories than are healthy workers. While many individuals remain with the same employer after the onset of health problems, many do switch employers and occupations, even in the presence of ADA legislation. [source] Propensity to Switch Auditors and Strictness of Legal Liability Environment: The Role of Audit MispricingINTERNATIONAL JOURNAL OF AUDITING, Issue 3 2007Juha-Pekka Kallunki This article investigates whether firms paying relatively high audit fees are more likely to switch auditors. Moreover, we investigate whether the legal liability environment affects the propensity to switch auditors owing to audit fee under- and/or over-pricing. Our empirical results from analysing the Compustat Global Vantage data from ten countries show that the over-pricing of auditing services increases the likelihood of auditor switches. We also find that a greater degree of under-pricing of auditing services in the initial audit engagement year is required to cause an auditor switch in countries with a stringent legal environment as opposed to countries with a lax legal environment. All the results remain unchanged after controlling for numerous firm and country differences. [source] Mechanism of Propensity to Atrial Fibrillation in Patients Undergoing Isthmus Ablation for Typical Atrial FlutterJOURNAL OF CARDIOVASCULAR ELECTROPHYSIOLOGY, Issue 2 2005HEMANTH RAMANNA M.D. Background: Patients undergoing isthmus ablation for atrial flutter (AFL) may reveal postablation atrial fibrillation (AF). The electrophysiological mechanism is unclear. In patients with idiopathic AF, enhanced spatial dispersion of right atrial refractoriness was the substrate for the initiation of AF. We hypothesize that dispersion of right atrial refractoriness in patients undergoing AFL ablation is the major cause of postablation AF. Methods: Consecutive patients (n = 42) undergoing isthmus ablation for typical AFL were included. Twelve right atrial unipolar electrograms were recorded. Inducibility of AF was assessed by a pacing protocol, starting with one extrastimulus, followed by more aggressive pacing until AF was induced. Mean fibrillatory intervals were used to assess local refractoriness of each recording site. Spatial dispersion of right atrial refractoriness was calculated as the coefficient of dispersion (CD-value: standard deviation of the mean of all local mean fibrillatory intervals as a percentage of the overall mean fibrillatory interval). A CD-value of 3.0 or less was defined as normal, whereas CD-value greater than 3.0 was considered enhanced dispersion. PES and refractoriness analysis were followed by isthmus ablation. Results: Of the 42 patients, 29 had CD-value of 3.0 or less. In these 29 patients, AF was induced with 1 extrastimulus in only 1 patient, with 2 extrastimuli in 4 patients and burst pacing was required to induce AF in 24 of these 29 patients. Prior to the procedure, 5 of 29 patients had AF episodes, after ablation 6 of 29 patients. Of the 42 patients, 13 had CD-value greater than 3.0, AF was induced with a single extrastimulus in 11 patients, with 2 extrastimuli in the remaining 2 patients. Of the 13 patients, 11 had AF episodes both before and after ablation (P < 0.001). Conclusion: Enhanced spatial dispersion of right atrial refractoriness may be the substrate for propensity to AF in patients with AFL. The substrate was associated with enhanced inducibility of atrial fibrillation. [source] Ultradian Corticosterone Rhythm and the Propensity to Behave Aggressively in Male RatsJOURNAL OF NEUROENDOCRINOLOGY, Issue 10 2000J. Haller Abstract Ultradian fluctuations in plasma glucocorticoids have been demonstrated in a variety of species including humans. The significance of such rhythms is poorly known, although disorganized ultradian glucocorticoid rhythms have been associated with behavioural disorders. Here we report that ultradian glucocorticoid rhythms may establish the propensity to behave aggressively in male rats. Male rats were significantly more aggressive in the increasing phase of their corticosterone fluctuation when confronting a male intruder than counterparts in the decreasing phase of their corticosterone fluctuations facing such opponents. Corticosterone fluctuations were mimicked by a combination of treatments with the corticosterone synthesis inhibitor metyrapone and corticosterone. Again, males with increased plasma corticosterone levels were more aggressive than counterparts with a decreased plasma corticosterone concentration. These data suggest that the behavioural response to an aggressive challenge may vary in the same animal across the day due to the pulsating nature of corticosterone secretion. Aggressive behaviour is also episodic in humans; moreover, intermittent explosive behaviour is recognized as a psychological disorder. It can be hypothesized that a temporal coincidence between the occurrence of a challenge and a surge in plasma corticosterone concentration may be one of the factors that promote episodic aggressive outbursts. [source] Changes in Sensation Seeking and Risk-Taking Propensity Predict Increases in Alcohol Use Among Early AdolescentsALCOHOLISM, Issue 8 2010Laura MacPherson Background:, Conceptual models implicating disinhibitory traits often are applied to understanding emergent alcohol use, but, little is known of how inter-individual changes in these constructs relate to increases in alcohol use in early adolescence. The current study utilized behavioral and self-report instruments to capture the disinhibitory-based constructs of sensation seeking and risk-taking propensity to examine if increases in these constructs over time related to increases in early adolescent alcohol use. Methods:, Participants included a community sample of 257 early adolescents (aged 9 to 12) who completed a self-report measure of sensation seeking, a behavioral task assessing risk-taking propensity, and a self-report of past year alcohol use, at 3 annual assessment waves. Results:, Both sensation seeking and risk-taking propensity demonstrated significant increases over time, with additional evidence that change in the behavioral measure of risk-taking propensity was not because of practice effects. Greater sensation seeking and greater risk-taking propensity demonstrated concurrent relationships with past year alcohol use at each assessment wave. Prospective analyses indicated that after accounting for initial levels of alcohol use, sensation seeking, and risk-taking propensity at the first assessment wave, larger increases in both constructs predicted greater odds of alcohol use at subsequent assessment waves. Conclusions:, Results indicate the role of individual changes in disinhibitory traits in initial alcohol use in early adolescents. Specifically, findings suggest it is not simply initial levels of sensation seeking and risk-taking propensity that contribute to subsequent alcohol use but in particular increases in each of these constructs that predict greater odds of use. Future work should continue to assess the development of sensation seeking and risk-taking propensity in early adolescence and target these constructs in interventions as a potential means to reduce adolescent alcohol use. [source] Propensity for non-alcoholic fatty liver disease: more evidence for ethnic susceptibilityLIVER INTERNATIONAL, Issue 1 2009R. Christopher Harmon No abstract is available for this article. [source] Tax Toleration and Tax Compliance: How Government Affects the Propensity of Firms to Enter the Unofficial EconomyAMERICAN JOURNAL OF POLITICAL SCIENCE, Issue 1 2010Douglas A. Hibbs How do government-supplied institutional benefits and the taxation and regulation of producers affect the propensity of private firms to enter the unofficial economy and evade taxation? We propose a model in which the incentive of firms to operate underground depends on tax rates relative to firm-specific thresholds of tax toleration that are decisively affected by quality of governance,in particular by the presence of high-grade institutions delivering services enhancing official production that anchor profit-maximizing firms to the official economy. Some key predictions of the model concerning the determinants of firms' tax toleration and tax compliance receive broad support from empirical analyses of enterprise-level data from the World Bank's World Business Environment Surveys. [source] ChemInform Abstract: Conversion of 4-Cyanomethyl-pyrazole-3-carboxamides into CB1 Antagonists with Lowered Propensity to Pass the Blood,Brain-Barrier.CHEMINFORM, Issue 23 2010Jean-Marie Receveur Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a "Full Text" option. The original article is trackable via the "References" option. [source] Development of the Video Assessment of Propensity to Use Emergency Restraints Scale (VAPERS): Results of the VAPERS Study GroupACADEMIC EMERGENCY MEDICINE, Issue 6 2007Darryl Macias MD Background:Emergency physicians (EPs) may disagree on when or whether patients need restraints. There is no good objective measure of the likelihood of EPs to restrain patients. Objectives:To 1) develop a scale to determine the likelihood that an EP would restrain a patient, 2) develop subscale scoring, and 3) determine a shortened version that correlates highly with the full scale. Methods:This was a prospective cross sectional study. The Video Assessment of Propensity to use Emergency Restraints Scale (VAPERS), consisting of 17 scenarios utilizing actors, was videotaped to produce a research video assessment tool. The VAPERS was designed by development experts to reflect the spectrum of patients who are considered for restraint in an emergency department. The VAPERS was piloted among a 22-member pilot panel of EPs (faculty and residents). The pilot panel was asked to determine the degree to which each video patient possessed the following patient characteristics: medical instability, trauma, belligerence, agitation, and altered mental status. Each "degree of characteristic" was measured on a separate 100-mm visual analog scale. Participants were then asked whether or not they would restrain each patient and whether the patient exhibited the potential to harm him- or herself or others. VAPERS subscales were developed for the likelihood to restrain patients with each of the patient characteristics. Spearman correlations were used for all comparisons. Linear regression was used to determine which patient characteristics were most related to likelihood to restrain and to develop a reduced scale to predict the overall likelihood to restrain. Results:The overall VAPERS score ranged from 0 to 100, with a median of 50 (interquartile range [IQR], 24,88). The visual analog scale results of how likely each video patient possessed specific characteristics were as follows: medical instability ranged from 0 to 100 (median, 32; IQR, 12,64), trauma ranged from 0 to 69 (median, 0; IQR, 0,31), belligerence ranged from 20 to 93 (median, 28; IQR, 14,63), agitation ranged from 3 to 84 (median, 52; IQR, 23,72), and altered mental status ranged from 1 to 93 (median, 29; IQR, 16,69). Linear regression indicated that two characteristic variables (danger to self and degree of agitation) in the video scenarios were highly correlated (0.87) with overall likelihood to restrain. Based on the results, the authors developed a shortened video assessment tool consisting of five of the original videos that were highly correlated (R= 0.94) with the full VAPERS scale on overall likelihood to restrain. Conclusions:The VAPERS scale covers a wide range of important variables in emergency situations. It successfully measured likelihood to restrain in this pilot study for overall situations, and for subgroups, based on patient characteristics. A shortened five-video VAPERS also successfully measured the overall likelihood to restrain. [source] Disgust and eating disorder symptomatology in a non-clinical population: The role of trait anxiety and anxiety sensitivityCLINICAL PSYCHOLOGY AND PSYCHOTHERAPY (AN INTERNATIONAL JOURNAL OF THEORY & PRACTICE), Issue 4 2009Graham C. L. Davey Abstract The present paper reports the results of a study investigating the relationship between a domains-independent measure of disgust (the Disgust Propensity and Sensitivity Scale-Revised) and measures of eating disorder symptomatology in a non-clinical population. Significant correlations between disgust sensitivity and disgust propensity and selected eating disorder symptomatology measures suggested that disgust is significantly correlated with measures of eating disorder symptomatology and is appraised more negatively. However, both measures of disgust propensity and sensitivity failed to predict any significant residual variance in scores on eating symptomatology measures when either trait anxiety or anxiety sensitivity was controlled for. This suggests that while the experience of disgust may be heightened in individuals with eating disorders, it may be linked to other relevant emotions such as anxiety and anxiety sensitivity rather than being an independent risk factor for symptoms.,Copyright © 2009 John Wiley & Sons, Ltd. Key Practitioner Message: The experience of disgust may be heightened in individuals with eating disorder symptomatology. Disgust levels may not be an independent predictor of eating disorder symptoms. In those with eating disorder symotomatology disgust may be linked to other emotions such as anxiety and anxiety sensitivity. [source] THE CONTEXT OF MARRIAGE AND CRIME: GENDER, THE PROPENSITY TO MARRY, AND OFFENDING IN EARLY ADULTHOOD,CRIMINOLOGY, Issue 1 2007RYAN D. KING Marriage is central to theoretical debates over stability and change in criminal offending over the life course. Yet, unlike other social ties such as employment, marriage is distinct in that it cannot be randomly assigned in survey research to more definitively assess causal effects of marriage on offending. As a result, key questions remain as to whether different individual propensities toward marriage shape its salience as a deterrent institution. Building on these issues, the current research has three objectives. First, we use a propensity score matching approach to estimate causal effects of marriage on crime in early adulthood. Second, we assess sex differences in the effects of marriage on offending. Although both marriage and offending are highly gendered phenomena, prior work typically focuses on males. Third, we examine whether one's propensity to marry conditions the deterrent capacity of marriage. Results show that marriage suppresses offending for males, even when accounting for their likelihood to marry. Furthermore, males who are least likely to marry seem to benefit most from this institution. The influence of marriage on crime is less robust for females, where marriage reduces crime only for those with moderate propensities to marry. We discuss these findings in the context of recent debates concerning gender, criminal offending, and the life course. [source] THE INITIAL IMPACTS OF A MATCHED SAVINGS PROGRAM: THE SAVER PLUS PROGRAMECONOMIC PAPERS: A JOURNAL OF APPLIED ECONOMICS AND POLICY, Issue 1 2006ROSLYN RUSSELL A major emphasis in policy focus in recent years has been to promote greater levels of saving and financial inclusion in Australia. A number of studies have identified that low-income households and households with children have lower saving propensities. This paper explores the effectiveness of a particular matched savings program, Saver Plus, in promoting savings amongst low-income families that are typically at the margin of the financial sector. While noting the limitations of the lack of a formal control group, the results appear to suggest that the Saver Plus program, with its involvement of community groups, a financial education component, and co-contribution arrangements may have been successful in encouraging savings behaviour. [source] Determination of dissociation constants of folic acid, methotrexate, and other photolabile pteridines by pressure-assisted capillary electrophoresisELECTROPHORESIS, Issue 17 2006Zoltán Szakács Abstract Pressure-assisted CE (PACE) was applied to determine the previously inaccessible complete set of pK values for folic acid and eight related multiprotic compounds. PACE allowed the determination of all acidity macroconstants at low (,0.1,mM) concentration without interferences of selfassociation or photodegradation throughout the pH range. The accuracy of the constants was verified by NMR-pH, UV-pH, and potentiometric titrations and the data could be converted into physiological ionic strength. It was shown that even three overlapping pK values can be determined by CE with good precision (<0.06) and accuracy if an appropriately low sample throughput is used. Experimental aspects of PACE for the quantitation of acid,base properties are analyzed. The site-specific basicity data obtained for folic acid and methotrexate (MTX) reveal that apparently slight constitutional differences between folic acid and MTX carry highly different proton-binding propensities at analogous moieties, especially at the pteridine N1,locus, providing straightforward explanation for the distinctive binding to dihydrofolate reductase at the molecular level. [source] Corporate Governance and Competitive Advantage in Family-Controlled FirmsENTREPRENEURSHIP THEORY AND PRACTICE, Issue 3 2005Michael Carney Recent attempts to identify the basis of family-controlled firms' competitive advantage have drawn upon the resource-based view of the firm. This article supplements these efforts and advances the argument that family-controlled firms' competitive advantage arises from their system of corporate governance. Systems of corporate governance embody incentives, authority patterns, and norms of legitimation that generate particular organizational propensities to create competitive advantages and disadvantages. For comparative purposes, the characteristics of managerial, alliance, and family governance are reviewed. The impact of a family's control rights over a firm's assets generates three dominant propensities (parsimony, personalism, and particularism). These propensities give advantages in scarce environments, facilitate the creation and utilization of social capital, and engender opportunistic investment processes. The experience of family-controlled firms in emerging markets is drawn upon to illustrate the argument. [source] CuI -Catalyzed Azide,Alkyne Intramolecular i -to-(i+4) Side-Chain-to-Side-Chain Cyclization Promotes the Formation of Helix-Like Secondary StructuresEUROPEAN JOURNAL OF ORGANIC CHEMISTRY, Issue 3 2010Mario Scrima Abstract A solid-phase assembly of model peptides derived from human parathyroid hormone-related protein (11,19) containing ,-azido- and ,-yl-,-amino acid residues in positions i and i+4 was cyclised in solution by an intramolecular CuI -catalyzed azide,alkyne 1,3-dipolar Huisgen cycloaddition. These series of heterodetic cyclo-nonapeptides varied in the size of the disubstituted 1,2,3-triazolyl-containing bridge, the location and the orientation of the 1,2,3-triazolyl moiety within the bridge. The 1,2,3-triazolyl moiety, presented at either 1,4- or 4,1-orientation, is flanked by side chains containing 1,4 CH2 groups that result in bridges comprised from 4,7 CH2 groups connecting residues 13 and 17. Comprehensive conformational analysis employing CD, NMR and molecular dynamics reveals the conformational propensities of these heterodetic cyclo-nonapeptides. Cyclo-nonapeptides containing either the 7 methylene bridge (VII and VIII) or the 4 methylene bridge (II) are unstructured in structure-promoting solvent. Cyclo-nonapeptide I in which the 1,4-disubstituted 1,2,3-triazolyl is flanked by 3 and 1 CH2 groups in proximity to the respective residues 13 and 17, is stabilized in a non-canonical structure. All the other heterodetic cyclo-nonapeptides (III,VI) in which the 1,2,3-triazolyl is flanked by a total of 5 or 6 CH2 groups nicely accommodate ,-helical structures and reproduce very closely the helical structure stabilized by the analogous cyclo-nonapeptide in which Lys13 and Asp17 are bridged by the isosteric lactam. These studies suggest that the bioorthogonal i -to-(i+4) side-chain-to-side-chain cyclization via the prototypic "click reaction" offers a new and powerful approach for generating stable helix mimetic structures. [source] Bias in the introduction of variation as an orienting factor in evolutionEVOLUTION AND DEVELOPMENT, Issue 2 2001Lev Y. Yampolsky SUMMARY According to New Synthesis doctrine, the direction of evolution is determined by selection and not by "internal causes" that act by way of propensities of variation. This doctrine rests on the theoretical claim that because mutation rates are small in comparison to selection coefficients, mutation is powerless to overcome opposing selection. Using a simple population-genetic model, this claim is shown to depend on assuming the prior availability of variation, so that mutation may act only as a "pressure" on the frequencies of existing alleles, and not as the evolutionary process that introduces novelty. As shown here, mutational bias in the introduction of novelty can strongly influence the course of evolution, even when mutation rates are small in comparison to selection coefficients. Recognizing this mode of causation provides a distinct mechanistic basis for an "internalist" approach to determining the contribution of mutational and developmental factors to evolutionary phenomena such as homoplasy, parallelism, and directionality. [source] Dynamics, stability and iron-binding activity of frataxin clinical mutantsFEBS JOURNAL, Issue 14 2008Ana R. Correia Friedreich's ataxia results from a deficiency in the mitochondrial protein frataxin, which carries single point mutations in some patients. In the present study, we analysed the consequences of different disease-related mutations in vitro on the stability and dynamics of human frataxin. Two of the mutations, G130V and D122Y, were investigated for the first time. Analysis by CD spectroscopy demonstrated a substantial decrease in the thermodynamic stability of the variants during chemical and thermal unfolding (wild-type > W155R > I154F > D122Y > G130V), which was reversible in all cases. Protein dynamics was studied in detail and revealed that the mutants have distinct propensities towards aggregation. It was observed that the mutants have increased correlation times and different relative ratios between soluble and insoluble/aggregated protein. NMR showed that the clinical mutants retained a compact and relatively rigid globular core despite their decreased stabilities. Limited proteolysis assays coupled with LC-MS allowed the identification of particularly flexible regions in the mutants; interestingly, these regions included those involved in iron-binding. In agreement, the iron metallochaperone activity of the Friedreich's ataxia mutants was affected: some mutants precipitate upon iron binding (I154F and W155R) and others have a lower binding stoichiometry (G130V and D122Y). Our results suggest that, in heterozygous patients, the development of Friedreich's ataxia may result from a combination of reduced efficiency of protein folding and accelerated degradation in vivo, leading to lower than normal concentrations of frataxin. This hypothesis also suggests that, although quite different from other neurodegenerative diseases involving toxic aggregation, Friedreich's ataxia could also be linked to a process of protein misfolding due to specific destabilization of frataxin. [source] NONPROFIT EMPLOYEES' MACHIAVELLIAN PROPENSITIESFINANCIAL ACCOUNTABILITY & MANAGEMENT, Issue 3 2009Pamela C. Smith Nonprofit organizations are held to high ethical standards due to their charitable missions serving the common good. Incidents of fiscal mismanagement within the nonprofit sector make it relevant to assay the ethical principles of employees. This study examines the level of Machiavellian propensities of US nonprofit employees. Results indicate Machiavellian propensities do exist in certain nonprofit employees and these employees agree with questionable behavior. Policy makers and oversight agencies may find these results useful in developing corporate governance and accountability measures for nonprofit organizations. Furthermore, board of director members may use these results to monitor employee actions and address management training. [source] Contributions of the mother,infant relationship to dissociative, borderline, and conduct symptoms in young adulthoodINFANT MENTAL HEALTH JOURNAL, Issue 3 2008Karlen Lyons-Ruth Recent high-risk longitudinal studies have documented a unique contribution of the quality of the early mother,child relationship to diverse forms of psychopathology in young adulthood, even with family economic status, later traumatic experiences, and some genetic factors controlled. In addition, measures of attachment-related deviations in caregiver,infant interaction predict more than measures of infant attachment behavior alone. This article reviews those findings in the context of cross-disciplinary thinking on the importance of shared subjectivities in human evolution and development and in the context of recent studies beginning to map the intersection between processes of interaction and the development of the child's propensities to share mental states with others. [source] Entropy-based metrics in swarm clusteringINTERNATIONAL JOURNAL OF INTELLIGENT SYSTEMS, Issue 9 2009Bo Liu Ant-based clustering methods have received significant attention as robust methods for clustering. Most ant-based algorithms use local density as a metric for determining the ants' propensities to pick up or deposit a data item; however, a number of authors in classical clustering methods have pointed out the advantages of entropy-based metrics for clustering. We introduced an entropy metric into an ant-based clustering algorithm and compared it with other closely related algorithms using local density. The results strongly support the value of entropy metrics, obtaining faster and more accurate results. Entropy governs the pickup and drop behaviors, while movement is guided by the density gradient. Entropy measures also require fewer training parameters than density-based clustering. The remaining parameters are subjected to robustness studies, and a detailed analysis is performed. In the second phase of the study, we further investigated Ramos and Abraham's (In: Proc 2003 IEEE Congr Evol Comput, Hoboken, NJ: IEEE Press; 2003. pp 1370,1375) contention that ant-based methods are particularly suited to incremental clustering. Contrary to expectations, we did not find substantial differences between the efficiencies of incremental and nonincremental approaches to data clustering. © 2009 Wiley Periodicals, Inc. [source] Gender and Ethnic Differences in Marital Assimilation in the Early Twentieth Century,INTERNATIONAL MIGRATION REVIEW, Issue 3 2005Sharon Sassler Historical research on intermarriage has overlooked how distinctive patterns of ethnic settlement shape partner choice and assumed that the mate selection process operated the same way for men and women. This study utilizes a sample of youn married adults drawn from the 1910 Census IPUMS to examine 1) whether ethnic variation in partner choice was shaped by differences in group concentration and distribution and 2) if factors shaping outmarriage were gendered. About one fifth of young married Americans had spouses of a different ethnic background in 1910, though there was considerable ethnic variation in outmarriage propensities. Barriers to intermarriage fell at different rates, depending upon ethnic grou, sex, and region of settlement; they were weakest for first-and seconl eneration English men. Structural factors such as group size operatef differently for men and women; while larger group representation increased men's odds of outmarriage to both native stock and other white ethnic wives, women from the ethnic groups with the largest presence were significantly more likely to wed fellow ethnics than the native stock. Ultimately, even if they resided in the same location, the marriage market operated in different ways for ethnic women and men in search of mates. [source] Childbearing after Migration: Fertility Patterns of Foreign-born Women in Sweden,INTERNATIONAL MIGRATION REVIEW, Issue 2 2004Gunnar Andersson The present study provides an investigation of patterns in childbearing among foreign-born women in Sweden from the 1960s to the 1990s. Event-history techniques are applied to longitudinal population register data on childbearing and migration of 446,000 foreign-born women who had ever lived in Sweden before the end of 1999. Period trends in parity-specific fertility appear to be quite similar for Swedish- and foreignborn women, but important differences exist in levels of childbearing propensities between women from different countries of origin. Most immigrant groups tend to display higher levels of childbearing shortly after immigration. We conclude that migration and family building in many cases are interrelated processes and that it is always important to account for time since migration when fertility of immigrants is studied. [source] The SAAP force field: Development of the single amino acid potentials for 20 proteinogenic amino acids and Monte Carlo molecular simulation for short peptides,JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 13 2009Michio Iwaoka Abstract Molecular simulation by using force field parameters has been widely applied in the fields of peptide and protein research for various purposes. We recently proposed a new all-atom protein force field, called the SAAP force field, which utilizes single amino acid potentials (SAAPs) as the fundamental elements. In this article, whole sets of the SAAP force field parameters in vacuo, in ether, and in water have been developed by ab initio calculation for all 20 proteinogenic amino acids and applied to Monte Carlo molecular simulation for two short peptides. The side-chain separation approximation method was employed to obtain the SAAP parameters for the amino acids with a long side chain. Monte Carlo simulation for Met-enkephalin (CHO-Tyr-Gly-Gly-Phe-Met-NH2) by using the SAAP force field revealed that the conformation in vacuo is mainly controlled by strong electrostatic interactions between the amino acid residues, while the SAAPs and the interamino acid Lennard-Jones potentials are predominant in water. In ether, the conformation would be determined by the combination of the three components. On the other hand, the SAAP simulation for chignolin (H-Gly-Tyr-Asp-Pro-Glu-Thr-Gly-Thr-Trp-Gly-OH) reasonably reproduced a native-like ,-hairpin structure in water although the C-terminal and side-chain conformations were different from the native ones. It was suggested that the SAAP force field is a useful tool for analyzing conformations of polypeptides in terms of intrinsic conformational propensities of the single amino acid units. © 2009 Wiley Periodicals, Inc. J Comput Chem, 2009 [source] Time-averaged predictions of folded and misfolded peptides using a reduced physicochemical modelJOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 7 2008Oliver J. Clarke Abstract Energy-based methods for calculating time-averaged peptide structures are important for rational peptide design, for defining local structure propensities in large protein chains, and for exploring the sequence determinants of amyloid formation. High-end methods are currently too slow to be practicable, and will remain so for the foreseeable future. The challenge is to create a method that runs quickly on limited computer resources and emulates reality sufficiently well. We have developed a simplified off-lattice protein model, incorporating semi-empirical physicochemical potentials, and combined it with an efficient Monte Carlo method for calculating time-averaged peptide structures. Reasonably accurate predictions are found for a set of small ,-helical and ,-hairpin peptides, and we demonstrate a potential application in measuring local structure propensities in protein chains. Time-averaged structures have also been calculated for a set of small peptides known to form ,-amyloid fibrils. The simulations were of three interacting peptides, and in each case the time-averaged structure describes a three-stranded ,-sheet. The performance of our method in measuring the propensities of small peptides to self-associate into possible prefibrillar species compares favorably with more detailed and CPU-intensive approaches. © 2007 Wiley Periodicals, Inc. J Comput Chem, 2008 [source] Burning and cutting: Identifying the traits of individuals with an enduring propensity to tan and to undergo cosmetic surgeryJOURNAL OF CONSUMER BEHAVIOUR, Issue 5 2009John C. Mowen The research investigated the trait predictors of the propensity to use two beautification procedures that have the potential to harm health , the propensities to tan and to obtain cosmetic surgery. The results of a survey of 231 adult consumers revealed that a different combination of hierarchically arranged traits was predictive of the two procedures. These results suggest that different strategies are required in order to market or demarket tanning and plastic surgery. The research also made methodological contributions by revealing that two forms of vanity identified in the literature , physical view vanity and physical concern vanity , represent two different constructs rather than two dimensions of an underlying construct. Copyright © 2009 John Wiley & Sons, Ltd. [source] | ||||||||||||||||||||||||||||