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Empirical

Distribution by Scientific Domains
Business, Economics, Finance and Accounting19%
Humanities and Social Sciences18%
Life Sciences15%
Medical Sciences11%
Chemistry10%
Psychology7%
Earth and Environmental Science4%
Physics and Astronomy2%
Engineering2%
Mathematics and Statistics2%
4 Other Domains10%

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  • empirical coverage probability
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  • empirical evidence
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  • empirical examination
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    • Selected Abstracts

    I. THEORETICAL, EMPIRICAL, AND PRACTICAL RATIONALE

    MONOGRAPHS OF THE SOCIETY FOR RESEARCH IN CHILD DEVELOPMENT, Issue 3 2008
    Article first published online: 24 NOV 200
    First page of article [source]

    IS IT TIME FOR BIOETHICS TO GO EMPIRICAL?

    BIOETHICS, Issue 3 2008
    CHRIS HERRERA
    ABSTRACT Observers who note the increasing popularity of bioethics discussions often complain that the social sciences are poorly represented in discussions about things like abortion and stem-cell research. Critics say that bioethicists should be incorporating the methods and findings of social scientists, and should move towards making the discipline more empirically oriented. This way, critics argue, bioethics will remain relevant, and truly reflect the needs of actual people. Such recommendations ignore the diversity of viewpoints in bioethics, however. Bioethics can gain much from the methods and findings from ethnographies and similar research. But it is misleading to suggest that bioethicists are unaware of this potential benefit. Not only that, bioethicists are justified in having doubts about the utility of the social science approach in some cases. This is not because there is some inherent superiority in non-empirical approaches to moral argument. Rather, the doubts concern the nature of the facts that the sciences would provide. Perhaps the larger point is that disagreements about the relationship between facts and normative arguments should be seen as part of the normal inquiry in bioethics, not evidence that reform is needed. [source]

    Board Monitoring, Regulation, and Performance in the Banking Industry: Evidence from the Market for Corporate Control

    CORPORATE GOVERNANCE, Issue 5 2010
    Jens Hagendorff
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: The specific monitoring effect of boards of directors versus industry regulation is unclear. In this paper, we examine how the interaction between bank-level monitoring and regulatory regimes influences the announcement period returns of acquiring banks in the US and twelve European economies. Research Findings/Insights: We study three board monitoring mechanisms , independence, CEO-chair duality, and diversity , and analyze their effectiveness in preventing underperforming merger strategies under bank regulators of varying strictness. Only under strict banking regulation regimes, do board independence and diversity improve acquisition performance. In less strict regulatory environments, corporate governance is virtually irrelevant in improving the performance outcomes of merger activities. Theoretical/Academic Implications: Our results indicate a complementary role between monitoring by boards and bank regulation. This study is the first to report evidence consistent with complementarity by investigating the effectiveness (rather than the prevalence) of governance arrangements across regulatory regimes. Practitioner/Policy Implications: Our work offers insights to policymakers charged with improving the quality of decision-making at financial institutions. Attempts to improve the ability of bank boards to critically assess managerial initiatives are most likely to be successful if internal governance is accompanied by strict industry regulation. [source]

    Antecedents of Shareholder Activism in Target Firms: Evidence from a Multi-Country Study

    CORPORATE GOVERNANCE, Issue 4 2010
    William Q. Judge
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: This study seeks to better understand the antecedents of shareholder activism targeted at firms located in three common law countries (i.e., USA, UK, and Australia) and three civil law countries (Japan, Germany, and South Korea) during the 2003,07 time period. Research Findings/Insights: Our findings suggest that the antecedents of shareholder activism vary by the motivation of the activist. We demonstrate that activists target firms with two motives (a) to improve the financial performance, and (b) to improve the social performance of the firm. With respect to the target firm level antecedents, we find that firm size is unrelated to financial activism, but positively related to social activism; ownership concentration is negatively related to both financial and social activism; and prior profitability is negatively related to financial activism, but positively related to social activism. Further, these relationships in the case of financial activism are generally stronger in common law legal systems, whereas those in the case of social activism are generally stronger in environments with a greater level of income inequality. Theoretical/Academic Implications: Our findings suggest that future research should differentiate between the motivations of the activism event. Further, we find that while agency logic works well for financial activism, institutional theory provides stronger explanations for social activism. Overall, we demonstrate the complementary nature of these two theories in explaining shareholder activism. Practitioner/Policy Implications: We found that the "exposure" to shareholder activism varies by the motivation of the activist, and the nature of the firm and its national context. An understanding of these issues would help firms develop proper response strategies to activism events. [source]

    National Adoption of International Accounting Standards: An Institutional Perspective

    CORPORATE GOVERNANCE, Issue 3 2010
    William Judge
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: Effective corporate governance requires accurate and reliable financial information. Historically, each nation has developed and pursued its own financial standards; however, as financial markets consolidate into a global market, there is a need for a common set of financial standards. As a result, there is a movement towards harmonization of international financial reporting standards (IFRS) throughout the global economy. While there has been considerable research on the effects of IFRS adoption, there has been relatively little systematic study as to the antecedents of IFRS adoption. Consequently, this study seeks to understand why some economies have quickly embraced IFRS standards while others partially adopt IFRS and still others continue to resist. Research Findings/Results: After controlling for market capitalization and GDP growth, we find that foreign aid, import penetration, and level of education achieved within a national economy are all predictive of the degree to which IFRS standards are adopted across 132 developing, transitional and developed economies. Theoretical/Academic Implications: We found that all three forms of isomorphic pressures (i.e., coercive, mimetic, and normative) are predictive of IFRS adoption. Consequently, institutional theory with its emphasis on legitimacy-seeking by social actors was relatively well supported by our data. This suggests that the IFRS adoption process is driven more by social legitimization pressures, than it is by economic logic. Practitioner/Policy Implications: For policy makers, our findings suggest that the institutional pressures within an economy are the key drivers of IFRS adoption. Consequently, policy makers should seek to influence institutional pressures that thwart and/or enhance adoption of IFRS. For executives of multinational firms, our findings provide insights that can help to explain and predict future IFRS adoption within economies where their foreign subsidiaries operate. This ability could be useful for creating competitive advantages for foreign subsidiaries where IFRS adoption was resisted, or avoiding competitive disadvantages for foreign subsidiaries unfamiliar with IFRS standards. [source]

    Corporate-Governance Ratings and Company Performance: A Cross-European Study

    CORPORATE GOVERNANCE, Issue 2 2010
    Annelies Renders
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: Prior studies have failed to unequivocally establish a positive relationship between corporate-governance ratings and company performance, although theoretically, we would expect to find one. In this paper, we try to establish whether a positive relationship exists through modeling the relationship more carefully. Research Findings/Insights: After controlling for selection bias and endogeneity simultaneously, we find a significant positive relationship between corporate-governance ratings and performance. However, the strength of this relationship seems to depend on the quality of the institutional environment. Finally, we find that improvements in corporate-governance ratings over time result in decreasing marginal benefits in terms of performance. Theoretical/Academic Implications: Our paper contributes to the literature by showing that improved corporate-governance ratings lead to better performance, but that econometric problems might obscure this relationship. We also show that for a sample of developed countries the institutional environment affects the relationship between governance ratings and performance. Finally, this paper contributes to the literature on the impact, regarding compliance and effectiveness, of codes of good governance. Practitioner/Policy Implications: Our results are relevant for both companies and policy makers. They indicate that companies can improve performance by adhering to good corporate-governance practices. For policy makers, the findings suggest that soft laws and the invisible hand of the market lead to companies improving their corporate governance. [source]

    Optimal Board Monitoring in Family-owned Companies: Evidence from Asia

    CORPORATE GOVERNANCE, Issue 1 2010
    En-Te Chen
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: We propose that high levels of monitoring are not always in the best interests of minority shareholders. In family-owned companies the optimal level of board monitoring required by minority shareholders is expected to be lower than that of other companies. This is because the relative benefits and costs of monitoring are different in family-owned companies. Research Findings/Insights: At moderate levels of board monitoring, we find concave relationships between board monitoring variables and firm performance for family-owned companies but not for other companies. The optimal level of board monitoring for our sample of Asian family-owned companies equates to board independence of 38 per cent, separation of the chairman and CEO positions, and establishment of audit and remuneration committees. Additional testing shows that the optimal level of board monitoring is sensitive to the magnitude of the agency conflict between the family group and minority shareholders and the presence of substitute monitoring. Theoretical/Academic Implications: This study shows that the effect of additional monitoring on agency costs and firm performance differs across firms with different ownership structures. Practitioner/Policy Implications: For policymakers, the results show that more monitoring is not always in the best interests of minority shareholders. Therefore, it may be inappropriate for regulators to advise all companies to follow the same set of corporate governance guidelines. However, our results also indicate that the board governance practices of family-owned companies are still well below the identified optimal levels. [source]

    Financing Constraints, Ownership Control, and Cross-Border M&As: Evidence from Nine East Asian Economies

    CORPORATE GOVERNANCE, Issue 6 2009
    Yenn-Ru Chen
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: This study distinguishes between the effects of financial constraint determinants on cross-border mergers and acquisitions (M&As) and domestic M&As for all takeover bids announced in nine East Asian economies from 1998 to 2005. Research Findings/Insights: The results of logistic regressions verify that the extent of stock market and governance developments improves corporate financing conditions and subsequently encourages cross-border M&As in East Asia. The results also indicate that, except for ownership control variables, the firm-specific factors of financing constraints reduce the occurrence of cross-border M&As relative to domestic M&As. Although family- and state-controlled firms have better access to external financing, they are reluctant to risk diluting their management control and thus prefer domestic M&As to cross-border deals. Theoretical/Academic Implications: This study enhances the empirical studies of the relation between financing constraints and corporate investments based on the market imperfection hypothesis of corporate finance theories. In addition, this study also addresses the interaction between the market imperfection hypothesis and agency theory in explaining the effects of special ownership control on cross-border M&As relative to domestic deals. Furthermore, by examining the research questions across nine East Asian economies, this study provides an understanding of how such a relation applies to firms in countries where information asymmetry is high. Practitioner/Policy Implications: The findings indicate the importance of corporate governance and verify the effects of unique organizational structures on major corporate decisions. Specifically, family-controlled firms are often free of the financing constraints inherent in investment decisions. Thus, it is necessary to consider such organizational uniqueness when explaining the financing behavior of cross-border M&As conducted by Asian firms. [source]

    Capital Investment and Earnings: International Evidence

    CORPORATE GOVERNANCE, Issue 5 2009
    Ahmet Can Inci
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: We examine the nature of the dynamic linkage (causality) between earnings and capital investment using firm-level data from around the world to see whether the legal environment, including corporate governance and monitoring mechanisms, and financial development are important in the profitability of capital investment. Research Findings/Insights: Using firms in 40 countries over the period 1988,2004, we find that the causality from earnings to capital investment is positive and strong in almost all countries, irrespective of the type of legal system and the degree of financial development. However, the causality from capital investment to earnings is generally negative for firms in civil law and financially undeveloped countries, while the causality is generally positive in common law and financially developed countries. Therefore, our international cross-country study enables us to find that the legal system and financial development are factors in the determination of the profitability of capital investment. Theoretical/Academic Implications: Our findings imply that internal financing is a significant constraint for capital investment, which provides support for the pecking order theory even for financially developed markets and for the free cash flow theory. Common law and financially developed countries tend to provide better shareholder protection with more efficient corporate governance and better investment decisions. Practitioner/Policy Implications: To encourage managers to make capital investments in value-increasing projects, it is important to further improve a legal environment that includes corporate governance, monitoring, and incentive mechanisms. Financial development that includes effective financial regulatory agencies should be sought. [source]

    Business Group Affiliation, Firm Governance, and Firm Performance: Evidence from China and India

    CORPORATE GOVERNANCE, Issue 4 2009
    Deeksha A. Singh
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: This study seeks to understand how business group affiliation, within firm governance and external governance environment affect firm performance in emerging economies. We examine two aspects of within firm governance , ownership concentration and board independence. Research Findings/Insights: Using archival data on the top 500 Indian and Chinese firms from multiple data sources for 2007, we found that group affiliated firms performed worse than unaffiliated firms, and the negative relationship was stronger in the case of Indian firms than for Chinese firms. We also found that ownership concentration had a positive effect on firm performance, while board independence had a negative effect on firm performance. Further, we found that group affiliation , firm performance relationship in a given country context was moderated by ownership concentration. Theoretical/Academic Implications: This study utilizes an integration of agency theory with an institutional perspective, providing a more comprehensive framework to analyze the CG problems, particularly in the emerging economy firms. Empirically, our findings support, as well as contradict, some of the conventional wisdom, and suggest useful avenues for future research. Practitioner/Policy Implications: This study shows that reforms in general and CG reforms in particular are effective in emerging economies, which is an encouraging sign for policy makers. However, our research also suggests that it may be time for India and China to stop the encouragement for the empire building through group formation in the corporate world. For practioners, our findings suggest that firms need to balance the need for oversight with the need for advice, while selecting independent directors. [source]

    Is CEO Duality Always Negative?

    CORPORATE GOVERNANCE, Issue 2 2009
    An Exploration of CEO Duality, Ownership Structure in the Arab IPO Context
    ABSTRACT Manuscript type: Empirical Research Question/Issue: This paper examines the relationships between initial public offering (IPO) underpricing, CEO duality, and strategic ownership in 12 Arab countries of the Middle East and North Africa (MENA) region. Research Findings/Results: Using all IPOs from January 2000 until the end of July 2007, we document an average IPO underpricing of 184.1 per cent. Underpricing is higher in IPO firms that have CEO duality. However, strategic shareholders, such as corporations and other industry-related investors, are likely to play a monitoring role whereas underpricing is found to be lower in firms with both CEO duality and strategic shareholder ownership. Moreover, the negative relation between underpricing and strategic blockholding is greater for foreign strategic ownership than it is for domestic strategic ownership. Theoretical Implications: This paper examines the level and determinants of IPO underpricing in the MENA region. It provides evidence on the role played by foreign strategic owners in reducing agency conflicts and information asymmetries within an environment where firms may be affected by the cultural issues related to political ties and family involvement. Practical Implications: Our results contribute to the existing debate on the appropriate regulations for an effective and stable financial system in Arab countries. They offer policy-makers additional evidence on the positive impact of market openness to foreign shareholders. [source]

    The Effect of National Governance Codes on Firm Disclosure Practices: Evidence from Analyst Earnings Forecasts

    CORPORATE GOVERNANCE, Issue 6 2008
    John Nowland
    ABSTRACT Manuscript Type: Empirical Research Question: This study examines whether voluntary national governance codes have a significant effect on company disclosure practices. Two direct effects of the codes are expected: 1) an overall improvement in company disclosure practices, which is greater when the codes have a greater emphasis on disclosure; and 2) a leveling out of disclosure practices across companies (i.e., larger improvements in companies that were previously poorer disclosers) due to the codes new comply-or-explain requirements. The codes are also expected to have an indirect effect on disclosure practices through their effect on company governance practices. Research Findings/Results: The results show that the introduction of the codes in eight East Asian countries has been associated with lower analyst forecast error and a leveling out of disclosure practices across companies. The codes are also found to have an indirect effect on company disclosure practices through their effect on board independence. Practical Implications: This study shows that a regulatory approach to improving disclosure practices is not always necessary. Voluntary national governance codes are found to have both a significant direct effect and a significant indirect effect on company disclosure practices. In addition, the results indicate that analysts in Asia do react to changes in disclosure practices, so there is an incentive for small companies and family-owned companies to further improve their disclosure practices. [source]

    National Culture and the Composition and Leadership Structure of Boards of Directors

    CORPORATE GOVERNANCE, Issue 5 2008
    Jiatao Li
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: How and to what extent does national culture influence the composition and leadership structure of the boards of directors of multinational firms? Research Findings/Insights: Societal norms about corporate structure are treated as components of national culture. Hofstede's measures of national culture were shown to predict the board composition and leadership structure of firms based in that culture. The hypotheses were tested with data on 399 multinational manufacturing firms based in 15 industrial countries. The results suggest that national culture can have strong effects on corporate governance and should be considered in any transnational study. Theoretical/Academic Implications: The predictive accuracy of the culture variables provides strong support for the argument that norms embedded in a society's culture affect organizational structure, at least at the board level. The results of the study contribute to our understanding of institutional theory in explaining observed variations in corporate board composition and leadership structure across countries. By linking board composition to the cultural environment, institutional theory provides an explicit framework for analyzing variations in board structure across national boundaries. Practitioner/Policy Implications: When considering board composition and leadership structure, it is important to consider national culture norms. The findings of the study also have important implications for multinational firms setting up boards for their subsidiaries in different countries. [source]

    Patterns of Compliance with the German Corporate Governance Code

    CORPORATE GOVERNANCE, Issue 4 2008
    Till Talaulicar
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: This study investigates whether the form of compliance with the recommendations of the German Corporate Governance Code (GCGC) appears to be idiosyncratic to a specific company or features similarities across firms. The major aim of this research is thus to explore the ability of a classification of compliance patterns to account for the similarities and differences between firms regarding their conformity with the GCGC. Research Findings/Insights: Based on seven dimensions of code compliance, cluster analysis is used to identify discrete groups of companies with similar patterns of code observance. We determine eight patterns of compliance which are characterized by distinct forms of code conformity. Theoretical Academic Implications: The identified cluster solution does not merely reflect the number of rejected code recommendations. Rather, companies with very similar rates of overall compliance with the GCGC are assigned to different clusters because they feature, at the same time, different patterns of code conformity. These findings imply that governance prediction and governance performance studies have to overcome overly aggregated measures of code compliance which only incorporate the number of rejected code recommendations. Practitioner/Policy Implications: This study provides evidence to practitioners and policy makers that firms can be classified regarding their compliance with the code recommendations. In-depth analyses of the identified patterns of compliance furthermore reveal that some patterns may indicate less well substantiated deviations from the code and partly even decouplings of the declared compliance practices. [source]

    Why Adopt Codes of Good Governance?

    CORPORATE GOVERNANCE, Issue 1 2008
    A Comparison of Institutional, Efficiency Perspectives
    ABSTRACT Manuscript Type: Empirical Research Question/Issue: Given the global diffusion and the relevance of codes of good governance, the aim of this article is to investigate if the main reason behind their proliferation in civil law countries is: (i) the determination to improve the efficiency of the national governance system; or (ii) the will to "legitimize" domestic companies in the global financial market without radically improving the governance practices. Research Findings/Insights: We collected corporate governance codes developed worldwide at the end of 2005, and classified them according to the country's legal system (common or civil law). Then, we made a comparative analysis of the scope, coverage, and strictness of recommendations of the codes. We tested differences between common law and civil law countries using t-tests and probit models. Our findings suggest that the issuance of codes in civil law countries be prompted more by legitimation reasons than by the determination to improve the governance practices of national companies. Theoretical/Academic Implications: The study contributes to enriching our knowledge on the process of reinvention characterizing the diffusion of new practices. Our results are consistent with a symbolic perspective on corporate governance, and support the view that diffusing practices are usually modified or "reinvented" by adopters. Practitioner/Policy Implications: Our results support the idea that the characteristics of the national corporate governance system and law explain the main differences among the coverage of codes. This conclusion indicates the existence of a strong interplay between hard and soft law. [source]

    Technology Forecasting: From Emotional to Empirical

    CREATIVITY AND INNOVATION MANAGEMENT, Issue 2 2001
    Michael S. Slocum
    Technology Forecasting has evolved from being a methodology based on emotional responses to one predicated on data collection. The Theory of Inventive Problem Solving (TRIZ) is a theory based on empirical data that relates technological evolution to the same stages of biological macro-evolution. This paper will explore the major emotional forecasting methods as well as discuss part of TRIZ Technology Forecasting called Maturity Mapping. The reader will briefly be introduced to eight evolutionary trends based on TRIZ. [source]

    Optimal Design of the Online Auction Channel: Analytical, Empirical, and Computational Insights,

    DECISION SCIENCES, Issue 4 2002
    Ravi Bapna
    ABSTRACT The focus of this study is on business-to-consumer (B2C) online auctions made possible by the advent of electronic commerce over an open-source, ubiquitous Internet Protocol (IP) computer network. This work presents an analytical model that characterizes the revenue generation process for a popular B2C online auction, namely, Yankee auctions. Such auctions sell multiple identical units of a good to multiple buyers using an ascending and open auction mechanism. The methodologies used to validate the analytical model range from empirical analysis to simulation. A key contribution of this study is the design of a partitioning scheme of the discrete valuation space of the bidders such that equilibrium points with higher revenue structures become identifiable and feasible. Our analysis indicates that the auctioneers are, most of the time, far away from the optimal choice of key control factors such as the bid increment, resulting in substantial losses in a market with already tight margins. With this in mind, we put forward a portfolio of tools, varying in their level of abstraction and information intensity requirements, which help auctioneers maximize their revenues. [source]

    Empirical estimate of fundamental frequencies and damping for Italian buildings

    EARTHQUAKE ENGINEERING AND STRUCTURAL DYNAMICS, Issue 8 2009
    Maria Rosaria Gallipoli
    Abstract The aim of this work is to estimate the fundamental translational frequencies and relative damping of a large number of existing buildings, performing ambient vibration measurements. The first part of the work is devoted to the comparison of the results obtained with microtremor measurements with those obtained from earthquake recordings using four different techniques: horizontal-to-vertical spectral ratio, standard spectral ratio, non-parametric damping analysis (NonPaDAn) and half bandwidth method. We recorded local earthquakes on a five floors reinforced concrete building with a pair of accelerometers located on the ground and on top floor, and then collected microtremors at the same location of the accelerometers. The agreement between the results obtained with microtremors and earthquakes has encouraged extending ambient noise measurements to a large number of buildings. We analysed the data with the above-mentioned methods to obtain the two main translational frequencies in orthogonal directions and their relative damping for 80 buildings in the urban areas of Potenza and Senigallia (Italy). The frequencies determined with different techniques are in good agreement. We do not have the same satisfactory results for the estimates of damping: the NonPaDAn provides estimates that are less dispersed and grouped around values that appear to be more realistic. Finally, we have compared the measured frequencies with other experimental results and theoretical models. Our results confirm, as reported by previous authors, that the theoretical period,height relationships overestimate the experimental data. Copyright © 2008 John Wiley & Sons, Ltd. [source]

    Empirical and modeling evidence of regional atmospheric transport of current-use pesticides

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 10 2004
    Derek C. G. Muir
    Abstract Water samples from 30 lakes in Canada and the northeastern United States were analyzed for the occurrence of 27 current-use pesticides (CUPs). Eleven CUPs were frequently detected in lakes receiving agricultural inputs as well as in remote lakes hundreds of kilometers from known application areas. These included the triazine herbicide atrazine and its desethylated degradation product; the herbicides alachlor, metolachlor, and dacthal; the organophosphate insecticides chlorpyrifos, diazinon, and disulfoton; the organochlorine insecticides ,-endosulfan and lindane; and the fungicides chlorothalonil and flutriafol. For six of the pesticides, empirical half-distances on the order of 560 to 1,820 km were estimated from the water-concentration gradient with latitude. For most of the pesticides, a suite of assessment models failed to predict such atmospheric long-range transport behavior, unless the effect of periods of lower hydroxyl radical concentrations and dry weather were taken into account. Observations and model results suggest that under the conditions prevailing in south-central Canada (relatively high latitude, low precipitation rates), many CUPs will be able to undergo regional-scale atmospheric transport and reach lakes outside areas of agricultural application. When assessing the potential of fairly reactive and water-soluble substances to undergo long-range transport, it is imperative to account for periods of no precipitation, to assure that degradation rate constants are correct, and to apply oxidant concentrations that are valid for the region and time period of interest. [source]

    DIFFERENTIAL PATTERNS OF INTROGRESSION ACROSS THE X CHROMOSOME IN A HYBRID ZONE BETWEEN TWO SPECIES OF HOUSE MICE

    EVOLUTION, Issue 9 2004
    Bret A. Payseur
    Abstract A complete understanding of the speciation process requires the identification of genomic regions and genes that confer reproductive barriers between species. Empirical and theoretical research has revealed two important patterns in the evolution of reproductive isolation in animals: isolation typically arises as a result of disrupted epistatic interactions between multiple loci and these disruptions map disproportionately to the X chromosome. These patterns suggest that a targeted examination of natural gene flow between closely related species at X-linked markers with known positions would provide insight into the genetic basis of speciation. We take advantage of the existence of genomic data and a well-documented European zone of hybridization between two species of house mice, Mus domesticus and M. musculus, to conduct such a survey. We evaluate patterns of introgression across the hybrid zone for 13 diagnostic X-linked loci with known chromosomal positions using a maximum likelihood model. Interlocus comparisons clearly identify one locus with reduced introgression across the center of the hybrid zone, pinpointing a candidate region for reproductive isolation. Results also reveal one locus with high frequencies of M. domesticus alleles in populations on the M. musculus side of the zone, suggesting the possibility that positive selection may act to drive the spread of alleles from one species on to the genomic background of the other species. Finally, cline width and cline center are strongly positively correlated across the X chromosome, indicating that gene flow of the X chromosome may be asymmetrical. This study highlights the utility of natural populations of hybrids for mapping speciation genes and suggests that the middle of the X chromosome may be important for reproductive isolation between species of house mice. [source]

    Informed Trading around Merger Announcements: An Empirical Test Using Transaction Volume and Open Interest in Options Market

    FINANCIAL REVIEW, Issue 2 2001
    Narayanan Jayaraman
    G14/G34 Abstract This paper provides empirical evidence on the level of trading activity in the stock options market prior to the announcement of a merger or an acquisition. Our analysis shows that there is a significant increase in the trading activity of call and put options for companies involved in a takeover prior to the rumor of an acquisition or merger. This result is robust to both the volume of option contracts traded and the open interest. The increased trading suggests that there is a significant level of informed trading in the options market prior to the announcement of a corporate event. In addition, abnormal trading activity in the options market appears to lead abnormal trading volume in the equity market. This finding supports the hypothesis that the options market plays an important role in price discovery. [source]

    Stress generation in depression: Reflections on origins, research, and future directions

    JOURNAL OF CLINICAL PSYCHOLOGY, Issue 9 2006
    Constance Hammen
    Depressed individuals report higher rates of stressful life events, especially those that have occurred in part because of the person's characteristics and behaviors affecting interpersonal interactions. Termed stress generation, this phenomenon draws attention to the role of the individual as an active contributor rather than passive player in his or her environment, and is therefore an example of action theory. In this article, the author speculates about the intellectual origins of her stress generation perspective, and notes somewhat similar transactional approaches to the stress-disorder link outside of depression research. The literature on stress generation in depression is reviewed, including studies that attempt to explore its correlates and predictors, covering clinical, contextual, family, genetic, cognitive, interpersonal, and personality variables. Empirical and conceptual gaps in our understanding of processes contributing to stressors in the lives of depressed people remain. The author concludes with suggestions for further research, with the goal of furthering understanding both of mechanisms of depression and of dysfunctional interpersonal processes, as well as development of effective interventions to help break the stress-recurrence cycle of depression. © 2006 Wiley Periodicals, Inc. J Clin Psychol 62: 1065,1082, 2006. [source]

    Demand for nonalcoholic beverages: The case of low-income households

    AGRIBUSINESS : AN INTERNATIONAL JOURNAL, Issue 3 2004
    Steven T. Yen
    Household beverage consumption is investigated using data from the National Food Stamp Program Survey conducted in the United States. A censored Translog demand system is estimated with the full-information maximum-likelihood procedure. All own-price effects are negative and significant, and whole milk, reduced-fat milk, juice, coffee, and tea are found to be net substitutes for soft drink. Thus, prices provide a partial answer to the declining consumption of milk and rising consumption of soft drink. Nutrition information and dietary beliefs also play important roles, highlighting the importance of an effective nutrition education program directed toward the low-income households. [JEL citation: C34 (Truncated and Censored Models), D12 (Consumer Economics: Empirical), Q18 (Agricultural Policy; Food Policy).] © 2004 Wiley Periodicals, Inc. Agribusiness 20: 309,321, 2004. [source]

    Co-Authorship in Management and Organizational Studies: An Empirical and Network Analysis*

    JOURNAL OF MANAGEMENT STUDIES, Issue 5 2006
    Francisco José Acedo
    In recent decades there has been growing interest in the nature and scale of scientific collaboration. Studies into co-authorship have taken two different approaches. The first one attempts to analyse the reasons why authors collaborate and the consequences of such decision (Laband and Tollison, 2000). The second approach is based on the idea that co-authorship creates a social network of researchers (Barabási et al., 2002; Moody, 2004; Newman, 2001). In this study we have carried out an exploratory analysis of co-authorships in the field of management from the two aforementioned approaches. The results obtained show a growing tendency of the co-authored papers in the field of management, similar to what can be observed in other disciplines. Our study analyses some of the underpinning factors, which have been highlighted in the literature, explaining this tendency. Thus, the progressive quantitative character of research and the influence of the collaboration on the articles' impact are enhanced. The network analysis permits the exploration of the peculiarities of the management in comparison with other fields of knowledge, as well as the existing linkages between the most central and prominent authors within this discipline. [source]

    A new approach to batch process optimization using experimental design

    AICHE JOURNAL, Issue 2 2009
    Paul J. Wissmann
    Abstract Empirical and mechanistic experimental design methods are combined to construct partial models, which are, thus, used to design a process. The grid algorithm restricts the next experimental point to potential process optima, according to the confidence intervals around the optimal points, and works with any experimental design algorithm such as D-optimal. Two case studies show the advantages of implementing the grid algorithm. On average the improvement due to the grid algorithm was 15,20% in the first case study. The second case study is based on thin film growth using four potential models, with the most probable model used for experimental design. The grid algorithm balances the trade-off between two extremes: D-optimal designs and sampling at the predicted optimal point. The methodology presented shows that the experimenter does not have to decide ahead of time on purely empirical or mechanistic experimental design methods, since both may be useful. © 2008 American Institute of Chemical Engineers AIChE J, 2009 [source]

    Empirical-based recovery and maintenance of input error-correction features

    JOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 6 2007
    Minh Ngoc Ngo
    Abstract Most information systems deal with inputs submitted from their external environments. In such systems, input validation is often incorporated to reject erroneous inputs. Unfortunately, many input errors cannot be detected automatically and therefore result in errors in the effects raised by the system. Therefore, the provision of input error-correction features (IECFs) to correct these erroneous effects is critical. However, recovery and maintenance of these features are complicated, tedious and error prone because there are many possible input errors during user interaction with the system; each input error, in turn, might result in several erroneous effects. Through empirical study, we have discovered some interesting control flow graph patterns with regard to the implementation of IECFs in information systems. Motivated by these initial findings, in this paper, we propose an approach to the automated recovery of IECFs by realizing these patterns from the source code. On the basis of the recovered information, we further propose a decomposition-slicing technique to aid the maintenance of these features without interfering with other parts of the system. A case study has been conducted to show the usefulness of the proposed approach. Copyright © 2007 John Wiley & Sons, Ltd. [source]

    Non-parametric habitat models with automatic interactions

    JOURNAL OF VEGETATION SCIENCE, Issue 6 2006
    Bruce McCune
    Abstract Questions: Can a statistical model be designed to represent more directly the nature of organismal response to multiple interacting factors? Can multiplicative kernel smoothers be used for this purpose? What advantages does this approach have over more traditional habitat modelling methods? Methods: Non-parametric multiplicative regression (NPMR) was developed from the premises that: the response variable has a minimum of zero and a physiologically-determined maximum, species respond simultaneously to multiple ecological factors, the response to any one factor is conditioned by the values of other factors, and that if any of the factors is intolerable then the response is zero. Key features of NPMR are interactive effects of predictors, no need to specify an overall model form in advance, and built-in controls on overfitting. The effectiveness of the method is demonstrated with simulated and real data sets. Results: Empirical and theoretical relationships of species response to multiple interacting predictors can be represented effectively by multiplicative kernel smoothers. NPMR allows us to abandon simplistic assumptions about overall model form, while embracing the ecological truism that habitat factors interact. [source]

    Pragmatic Abilities in Autism Spectrum Disorder: A Case Study in Philosophy and the Empirical

    MIDWEST STUDIES IN PHILOSOPHY, Issue 1 2007
    JESSICA DE VILLIERS
    First page of article [source]

    Testing the accuracy of synthetic stellar libraries

    MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2007
    Lucimara P. Martins
    ABSTRACT One of the main ingredients of stellar population synthesis models is a library of stellar spectra. Both empirical and theoretical libraries are used for this purpose, and the question about which one is preferable is still debated in the literature. Empirical and theoretical libraries are being improved significantly over the years, and many libraries have become available lately. However, it is not clear in the literature what are the advantages of using each of these new libraries, and how far behind models are compared to observations. Here we compare in detail some of the major theoretical libraries available in the literature with observations, aiming at detecting weaknesses and strengths from the stellar population modelling point of view. Our test is twofold: we compared model predictions and observations for broad-band colours and for high-resolution spectral features. Concerning the broad-band colours, we measured the stellar colour given by three recent sets of model atmospheres and flux distributions, and compared them with a recent UBVRIJHK calibration which is mostly based on empirical data. We found that the models can reproduce with reasonable accuracy the stellar colours for a fair interval in effective temperatures and gravities. The exceptions are (1) the U,B colour, where the models are typically redder than the observations, and (2) the very cool stars in general (V,K, 3). Castelli & Kurucz is the set of models that best reproduce the bluest colours (U,B, B,V) while Gustafsson et al. and Brott & Hauschildt more accurately predict the visual colours. The three sets of models perform in a similar way for the infrared colours. Concerning the high-resolution spectral features, we measured 35 spectral indices defined in the literature on three high-resolution synthetic libraries, and compared them with the observed measurements given by three empirical libraries. The measured indices cover the wavelength range from ,3500 to ,8700 Ĺ. We found that the direct comparison between models and observations is not a simple task, given the uncertainties in parameter determinations of empirical libraries. Taking that aside, we found that in general the three libraries present similar behaviours and systematic deviations. For stars with Teff, 7000 K, the library by Coelho et al.is the one with best average performance. We detect that lists of atomic and molecular line opacities still need improvement, specially in the blue region of the spectrum, and for the cool stars (Teff, 4500 K). [source]

    The Philosophy of Social Science: Metaphysical and Empirical

    PHILOSOPHY COMPASS (ELECTRONIC), Issue 6 2007
    Francesco Guala
    Ontological debates have always been prominent in the philosophy of social science. Philosophers have typically conceived of such debates as pre-scientific attempts to reform social scientific practice, rather than as post-scientific reflections on a firm body of scientific knowledge. Two celebrated contemporary research programs in social ontology , collective intentionality and evolutionary game theory , also follow this approach. In this paper I illustrate their central elements and criticize their weak empirical foundations. I finish by reviewing some work that combines empirical evidence with theoretical reflection, and suggest that it constitutes the way forward in the philosophy of social science. [source]