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Find Evidence (find + evidence)
Kinds of Find Evidence Selected AbstractsTesting for criticality in ecosystem dynamics: the case of Amazonian rainforest and savanna fireECOLOGY LETTERS, Issue 7 2010Salvador Pueyo Ecology Letters (2010) 13: 793,802 Abstract We test for two critical phenomena in Amazonian ecosystems: self-organized criticality (SOC) and critical transitions. SOC is often presented in the complex systems literature as a general explanation for scale invariance in nature. In particular, this mechanism is claimed to underlie the macroscopic structure and dynamics of terrestrial ecosystems. These would be inextricably linked to the action of fire, which is conceived as an endogenous ecological process. We show that Amazonian savanna fires display the scale-invariant features characteristic of SOC but do not display SOC. The same is true in Amazonian rainforests subject to moderate drought. These findings prove that there are other causes of scale invariance in ecosystems. In contrast, we do find evidence of a critical transition to a megafire regime under extreme drought in rainforests; this phenomenon is likely to determine the time scale of a possible loss of Amazonian rainforest caused by climate change. [source] Caught in a Trap?ECONOMICA, Issue 268 2000Wage Mobility in Great Britain: 197 In this paper I study wage mobility in Great Britain using the New Earnings Surveys of 1975,94 and the British Household Panel Surveys of 1991,94. Measuring mobility in terms of decile transition matrices, I find a considerable degree of immobility within the wage distribution from one year to the next. Mobility is higher when measured over longer time periods. Those in lower deciles in the wage distribution are much more likely to exit into unemployment and non-employment. Measuring mobility by studying changes in individuals' actual percentile rankings in the wage distribution, I find evidence that short-run mobility rates have fallen since the late 1970s. This has potentially important welfare implications, given the rise in cross-section earnings inequality observed over the last two decades. [source] The Determinants and Implications of Mutual Fund Cash Holdings: Theory and EvidenceFINANCIAL MANAGEMENT, Issue 2 2006Xuemin (Sterling) Yan In this article, I examine the determinants and implications of equity mutual fund cash holdings. In cross-sectional tests, I find evidence generally supportive of a static trade-off model developed in the article. In particular, small-cap funds and funds with more-volatile fund flows hold more cash. However, I do not find that fund managers with better stock-picking skills hold less cash. Aggregate cash holdings by equity mutual funds are persistent and positively related to lagged aggregate fund flows. Aggregate cash holdings do not forecast future market returns, suggesting that equity funds as a whole do not have market timing skills. [source] Are active fund managers collectors of private information or fast interpreters of public information?ACCOUNTING & FINANCE, Issue 3 2010David R. Gallagher G23 Abstract Recent studies of fund manager performance find evidence of outperformance. However limited research exists as to whether such outperformance is because of privately collected information, or merely expedient interpretation of publicly released information. In this study, we examine the trade sequences of active Australian equity fund managers around earnings announcements to provide insights into the source of fund managers' superior information. We document an increased occurrence of buy-sell trade sequences around good-news earnings announcements. The evidence is consistent with fund managers having both private information about forthcoming good-news earnings announcements and being ,short-term profiteers'. We find no evidence that fund managers have private information about forthcoming bad-news earnings announcements. However, we do find an increase in the frequency of fund managers not trading before bad-news earnings announcements only to subsequently sell during announcements. [source] Valuing avoided morbidity using meta-regression analysis: what can health status measures and QALYs tell us about WTP?HEALTH ECONOMICS, Issue 8 2006George Van Houtven Abstract Many economists argue that willingness-to-pay (WTP) measures are most appropriate for assessing the welfare effects of health changes. Nevertheless, the health evaluation literature is still dominated by studies estimating nonmonetary health status measures (HSMs), which are often used to assess changes in quality-adjusted life years (QALYs). Using meta-regression analysis, this paper combines results from both WTP and HSM studies applied to acute morbidity, and it tests whether a systematic relationship exists between HSM and WTP estimates. We analyze over 230 WTP estimates from 17 different studies and find evidence that QALY-based estimates of illness severity , as measured by the Quality of Well-Being (QWB) Scale , are significant factors in explaining variation in WTP, as are changes in the duration of illness and the average income and age of the study populations. In addition, we test and reject the assumption of a constant WTP per QALY gain. We also demonstrate how the estimated meta-regression equations can serve as benefit transfer functions for policy analysis. By specifying the change in duration and severity of the acute illness and the characteristics of the affected population, we apply the regression functions to predict average WTP per case avoided. Copyright © 2006 John Wiley & Sons, Ltd. [source] Active versus passive teaching styles: An empirical study of student learning outcomesHUMAN RESOURCE DEVELOPMENT QUARTERLY, Issue 4 2009Norbert Michel This study compares the impact of an active teaching approach and a traditional (or passive) teaching style on student cognitive outcomes. Across two sections of an introductory business course, one class was taught in an active or "nontraditional" manner, with a variety of active learning exercises. The second class was taught in a passive or "traditional" manner, emphasizing daily lectures. Although the active learning approach does not appear to have improved overall mastery of the subject, we did find evidence that active learning can lead to improved cognitive outcomes in class-specific materials. The discussion emphasizes the role of delivery style on learning outcomes. [source] Debt Covenants and Accounting ConservatismJOURNAL OF ACCOUNTING RESEARCH, Issue 1 2010VALERI V. NIKOLAEV ABSTRACT Using a sample of over 5,000 debt issues, I test whether firms with more extensive use of covenants in their public debt contracts exhibit timelier recognition of economic losses in accounting earnings. Covenants govern the transfer of decision-making and control rights from shareholders to bondholders when a company approaches financial distress and thereby limit managers' abilities to expropriate bondholder wealth. Covenants are expected to constrain managerial opportunism, however, only if the accounting system recognizes economic losses in earnings in a timely fashion. Thus, the demand for timely loss recognition should increase with a contract's reliance on covenants. Consistent with this conjecture, I find evidence that reliance on covenants in public debt contracts is positively associated with the degree of timely loss recognition. I also find evidence that the presence of prior private debt mitigates this relationship. [source] Games Hospitals Play: Entry Deterrence in Hospital Procedure MarketsJOURNAL OF ECONOMICS & MANAGEMENT STRATEGY, Issue 3 2005Leemore S. Dafny Strategic investment models, though popular in the theoretical literature, have rarely been tested empirically. This paper develops a model of strategic investment in inpatient procedure markets, which are well-suited to empirical tests of this behavior. Potential entrants are easy to identify in such markets, enabling the researcher to accurately estimate the entry threat faced by different incumbents. I derive straightforward empirical tests of entry deterrence from a model of patient demand, procedure quality, and differentiated product competition. Using hospital data on electrophysiological studies, an invasive cardiac procedure, I find evidence of entry-deterring investment. These findings suggest that competitive motivations play a role in treatment decisions. [source] Persistent Policy Effects on the Division of Domestic Tasks in Reunified GermanyJOURNAL OF MARRIAGE AND FAMILY, Issue 4 2007Lynn Prince Cooke We are only beginning to unravel the mechanisms by which the division of domestic tasks varies in its sociopolitical context. Selecting couples from the German SocioEconomic Panel who married between 1990 and 1995 in the former East and West regions of Germany and following them until 2000 (N= 348 couples), I find evidence of direct, interaction, and contextual effects predicting husbands' hours in and share of household tasks but not child care. East German men perform a greater share of household tasks than West German men after controlling for individual attributes and regional factors. Child care remains more gendered, and the first child's age proves the most important predictor of fathers' involvement. These findings further our understanding of how the state shapes gender equity in the home. [source] The Impact of Central Bank Independence on Political Monetary Cycles in Advanced and Developing NationsJOURNAL OF MONEY, CREDIT AND BANKING, Issue 7 2009SAMI ALPANDA political monetary cycles; central bank independence This paper examines the extent to which monetary policy is manipulated for political purposes during elections. We do not detect political monetary cycles in advanced countries or developing nations with independent central banks. We do find evidence, however, in developing countries that lack central bank independence. Furthermore, we find some evidence that these cycles are not caused by monetization of election-related fiscal expansions. This suggests that pressure by politicians on the central bank to exploit the Phillips curve may be an important factor in generating political monetary cycles. [source] Evidence-based uncertainty in mental health nursingJOURNAL OF PSYCHIATRIC & MENTAL HEALTH NURSING, Issue 1 2004V. FRANKS rgn rnt dIPmed dIPpsych msC The drive towards evidence-based practice is part of a modern reflective and caring service. However there is a paradox at the heart of the notion of evidence-based care. In order to perform any systemized examination of treatment there has to be a conscious acknowledgement of uncertainty about that treatment. This is uncomfortable and when research does find evidence in favour of a treatment, there is a relief and a return to conviction about what is the best. The paradox is that it seems the most valued research practices are predicated on generalizations about patient treatments and categories. However, nursing care is based on the notion of the uniqueness of the patient and the nurse,patient relationship. Sometimes it is necessary to address the particular and not to rush to generalizations and certainty. The psychoanalytic framework promotes a capacity to tolerate uncertainty and provides a model for understanding conflicting feelings, which can occur within the nurse,patient relationship. The author proposes the psychoanalytic observational method as an adjunct to other research methods. This method places certain kinds of evidence within the rubric of evidence-based nursing practice. The evidence collected in this method is the evidence of the conscious and unconscious experience within the nurse,patient relationship. The author will describe and argue for the place of this research method within the canon of other more widely practised methods within mental health practice. She will propose that for safe practice it is necessary to value and examine the veracity of the feelings and tacit understanding of the nurse. She contends that the current climate of excessive bureaucracy and persecutory risk management is having a damaging effect on both the research process and effective nursing care. [source] Rhodopsin population genetics and local adaptation: variable dim-light vision in sand gobies is illuminatedMOLECULAR ECOLOGY, Issue 20 2009DANIEL EBERT The visual pigments of fish are thought to be adapted to the variable spectral qualities of aquatic light environments. Most research on the role of natural selection on the evolution of rhodopsins and dim-light vision in fish has focused on variation among species and higher taxa. In this issue, Larmuseau et al. reveal substantial intraspecific sequence variation in RH1 (the rhodopsin gene) in sand gobies (Pomatoschistus minutus). Using population genetics and molecular evolution approaches, they detect positive selection on RH1 and find evidence for adaptation to local light conditions. [source] Evolution in the discs and bulges of group galaxies since z= 0.4MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, Issue 4 2008Sean L. McGee ABSTRACT We present quantitative morphology measurements of a sample of optically selected group galaxies at 0.3 < z < 0.55 using the Hubble Space Telescope (HST) Advanced Camera for Surveys (ACS) and the gim2d surface brightness fitting software package. The group sample is derived from the Canadian Network for Observational Cosmology Field Galaxy Redshift Survey (CNOC2) and follow-up Magellan spectroscopy. We compare these measurements to a similarly selected group sample from the Millennium Galaxy Catalogue (MGC) at 0.05 < z < 0.12. We find that, at both epochs, the group and field fractional bulge luminosity (B/T) distributions differ significantly, with the dominant difference being a deficit of disc-dominated (B/T < 0.2) galaxies in the group samples. At fixed luminosity, z= 0.4 groups have ,5.5 ± 2 per cent fewer disc-dominated galaxies than the field, while by z= 0.1 this difference has increased to ,19 ± 6 per cent. Despite the morphological evolution we see no evidence that the group environment is actively perturbing or otherwise affecting the entire existing disc population. At both redshifts, the discs of group galaxies have similar scaling relations and show similar median asymmetries as the discs of field galaxies. We do find evidence that the fraction of highly asymmetric, bulge-dominated galaxies is 6 ± 3 per cent higher in groups than in the field, suggesting there may be enhanced merging in group environments. We replicate our group samples at z= 0.4 and 0 using the semi-analytic galaxy catalogues of Bower et al. This model accurately reproduces the B/T distributions of the group and field at z= 0.1. However, the model does not reproduce our finding that the deficit of discs in groups has increased significantly since z= 0.4. [source] The Evolution of Individual Male Earnings in Great Britain: 1975,95THE ECONOMIC JOURNAL, Issue 460 2000Richard Dickens I study the dynamic structure of male wages in Great Britain using the New Earnings Survey Panel from 1975,95. Computing auto-covariances of individual wages by cohort I find evidence of a permanent component of earnings that increases over the life cycle and a highly persistent, serially correlated transitory component. In addition, the estimated variances of both these components have risen over this period, each explaining about half the rise in inequality. Using individual's occupation at age 22, I split the sample into four skill groups. I find some differences across these groups, with the rise in the permanent variance most important for the manual groups. [source] ESTIMATING IMPORT AND EXPORT DEMAND ELASTICITIES FOR MAURITIUS AND SOUTH AFRICAAUSTRALIAN ECONOMIC PAPERS, Issue 3 2010SEEMA NARAYAN In this paper, we re-estimate the import and the export demand functions for Mauritius and South Africa using time series data. We use the bounds tests for cointegration and find evidence of a long-run relationship between import demand, income and prices for both countries. Our long run elasticities reveal that domestic income and relative prices have significant effects on the import demand for both countries, with income being the most important determinant. Furthermore, we find that while South Africa's export demand is not responsive to relative prices or income; for Mauritius income is statistically significant. [source] International Patterns of Union MembershipBRITISH JOURNAL OF INDUSTRIAL RELATIONS, Issue 1 2007David G. Blanchflower This paper examines changes in unionization that have occurred over the last decade or so using individual level micro data on many countries, with particular emphasis on the United Kingdom, the United States and Canada. I document an empirical regularity not hitherto identified, namely the probability of being unionized follows an inverted U-shaped pattern in age, maximizing in the mid- to late 40s in 34 of the 38 countries I study. I consider the question of why union membership seems to follow a similar inverted U-shape pattern in age across countries with such diverse industrial relations systems. I find evidence that this arises in part because of cohort effects, but even when cohort effects are removed a U-shape remains. [source] Unemployment Hysteresis in Australian States and Territories: Evidence from Panel Data Unit Root TestsTHE AUSTRALIAN ECONOMIC REVIEW, Issue 2 2003Russell Smyth This article tests for hysteresis by applying panel data unit root tests to quarterly unemployment rates for Australian states and territories between 1982:2 and 2002:1. Panel tests proposed by Levin and Lin (1992) using ordinary least squares and O'Connell (1998) using feasible generalised least squares (which assume that under the alternative hypothesis of stationarity, all labour markets revert to the natural rate at the same speed) provide evidence in support of the natural rate hypothesis. However, the panel test proposed by Im, Pesaran and Shin (1997), which does not assume that all cross-sectional units converge towards the equilibrium value at the same speed under the alternative and is therefore less restrictive than the other two panel tests, finds evidence of hysteresis. Given the advantages of the Im et al. (1997) test over the other two panel tests the results can be interpreted as being consistent with the existence of hysteresis in unemployment [source] Are Employment Effects of Gender Discrimination Important?THE MANCHESTER SCHOOL, Issue 6 2003Some Evidence from Great Britain Interpreting the unexplained component of the gender wage gap as indicative of discrimination, the empirical literature to date has tended to ignore the potential impact wage discrimination may have on employment. Employment effects may arise if discrimination lowers the female offered wage and the labour supply curve is upward sloping. The empirical analysis employs the British Household Panel Study and finds evidence of both wage and associated employment effects. [source] Organizational Form and Expense Preference: Spanish ExperienceBULLETIN OF ECONOMIC RESEARCH, Issue 2 2002Iftekhar Hasan This article investigates the effect of alternative ownership structures, stock versus mutual, on the cost of production of Spanish depository institutions. By introducing a stochastic frontier analysis in estimating the best,practiced expense,preference behaviour, the empirical approach adjusts for the possibility that the two sectors of the banking industry employ different production technologies and finds evidence that is consistent with expense,preference behaviour by the mutual savings banks. [source] | ||||||||||||||||