Showing papers by "Dartmouth College published in 1998"

Corporate Ownership Around the World

Abstract: We present data on ownership structures of large corporations in 27 wealthy economies, making an effort to identify the ultimate controlling shareholders of these firms. We find that, except in economies with very good shareholder protection, relatively few of these firms are widely held, in contrast to the Berle and Means image of ownership of the modern corporation. Rather, these firms are typically controlled by families or the State. Equity control by financial institutions or other widely held corporations is far less common. The controlling shareholders typically have power over firms significantly in excess of their cash flow rights, primarily through the use of pyramids and participation in management. The results suggest that the central agency problem in large corporations around the world is that of restricting expropriation of minority shareholders by the controlling shareholders, rather than that of restricting empire building by professional managers unaccountable to shareholders.

Institutional analysis and the role of ideas in political economy

Abstract: L'A. montre de quelle maniere l'analyse institutionnelle permet de mettre en lumiere le role des idees au sein de l'economie politique. Il compare l'institutionnalisme historique developpe par K. Marx et celui developpe par Max Weber. Il s'interesse a l'institutionnalisme organisationnel de Frank Dobbin et de Mary Douglas. Il etudie l'influence des «idees» lors de l'elaboration des politiques de stimulation de l'economie aux Etats-Unis. Il estime que les idees peuvent etre envisagees comme des programmes, comme des paradigmes, comme des sentiments publics ou comme des cadres.

Morita Equivalence and Continuous-Trace $C^*$-Algebras

Abstract: The algebra of compact operators Hilbert $C^*$-modules Morita equivalence Sheaves, cohomology, and bundles Continuous-trace $C^*$-algebras Applications Epilogue: The Brauer group and group actions The spectrum Tensor products of $C^*$-algebras The imprimitivity theorem Miscellany Index Bibliography.

The Quality of Goverment

Abstract: We investigate empirically the determinants of the quality of governments in a large cross-section of countries. We assess government performance using measures of government intervention, public sector efficiency, public good provision, size of government, and political freedom. We find that countries that are poor, close to the equator, ethnolinguistically heterogeneous, use French of socialist laws, or have high proportions of Catholics or Muslims exhibit inferior government performance. We also find that the larger governments tend to be the better performing ones. The importance of historical factors in explaining the variation in government performance across countries sheds light on the economic, political, and cultural theories of institutions.

Models of community care for severe mental illness : A review of research on case management

Abstract: We describe different models of community care for persons with severe mental illness and review the research literature on case management, including the results of 75 studies. Most research has been conducted on the assertive community treatment (ACT) or intensive case management (ICM) models. Controlled research on ACT and ICM indicates that these models reduce time in the hospital and improve housing stability, especially among patients who are high service users. ACT and ICM appear to have moderate effects on improving symptomatology and quality of life. Most studies suggest little effect of ACT and ICM on social functioning, arrests and time spent in jail, or vocational functioning. Studies on reducing or withdrawing ACT or ICM services suggest some deterioration in gains. Research on other models of community care is inconclusive. We discuss the implications of the findings in terms of the need for specialization of ACT or ICM teams to address social and vocational functioning and substance abuse. We suggest directions for future research on models of community care, including evaluating implementation fidelity, exploring patient predictors of improvement, and evaluating the role of the helping alliance in mediating outcome.

How Much Does the CEO Matter? The Role of Managerial Discretion in the Setting of CEO Compensation

Abstract: The idea that managerial discretion—defined as latitude of action—may be an important determinant of CEO compensation has been recognized for some time. However, in spite of considerable work that ...

Measuring Market Orientation: Generalization and Synthesis

Abstract: This paper reports on an integrative, cross-nationalstudy which synthesizes and retests work of three separate groupsof researchers who in the late 1980‘s developed measurementsof a firm's Market Orientation. The projects resulted in threedifferent but syntactically similar Market Orientation scaleswhich, along with other measures, were used to support substantiveconclusions, particularly those involving firm Performance. Basedon a new study of 82 managers in 27 European and U.S. companies,we show that all three scales are reliable and valid. The scalesalso seem to generalize well internationally, both in terms ofreliability and prediction of Performance. We also show thatthe scales are similar to one another in terms of various validitymeasures and in terms of correlations with Performance measures.Finally, we synthesize a 10-item scale based on a more parsimoniousdefinition of Market Orientation as: ’’the set of cross-functionalprocesses and activities directed at creating and satisfyingcustomers through continuous needs-assessment.‘‘

Hippocampal volume reduction in schizophrenia as assessed by magnetic resonance imaging : A meta-analytic study

Abstract: Background Although many quantitative magnetic resonance imaging studies have found significant volume reductions in the hippocampi of patients with schizophrenia compared with those of normal control subjects, others have not. Therefore, the issue of hippocampal volume differences associated with schizophrenia remains in question. Methods Two meta-analyses were conducted to reduce the potential effects of sampling error and methodological differences in data acquisition and analysis. Eighteen studies with a total patient number of 522 and a total control number of 426 met the initial selection criteria. Results Meta-analysis 1 yielded mean effect sizes of 0.37 (P Conclusions Schizophrenia is associated with a bilateral volumetric reduction of the hippocampus and probably of the amygdala as well. These findings reinforce the importance of the medial temporal region in schizophrenia and are consistent with frequently reported memory deficits in these patients. Future quantitative magnetic resonance imaging studies evaluating the hippocampal volume should measure the hippocampus and amygdala separately and compare the volumetric reduction in these structures to that observed in other gray matter areas.

Identification of a family of zinc transporter genes from Arabidopsis that respond to zinc deficiency

Abstract: Millions of people worldwide suffer from nutritional imbalances of essential metals like zinc. These same metals, along with pollutants like cadmium and lead, contaminate soils at many sites around the world. In addition to posing a threat to human health, these metals can poison plants, livestock, and wildlife. Deciphering how metals are absorbed, transported, and incorporated as protein cofactors may help solve both of these problems. For example, edible plants could be engineered to serve as better dietary sources of metal nutrients, and other plant species could be tailored to remove metal ions from contaminated soils. We report here the cloning of the first zinc transporter genes from plants, the ZIP1, ZIP2, and ZIP3 genes of Arabidopsis thaliana. Expression in yeast of these closely related genes confers zinc uptake activities. In the plant, ZIP1 and ZIP3 are expressed in roots in response to zinc deficiency, suggesting that they transport zinc from the soil into the plant. Although expression of ZIP2 has not been detected, a fourth related Arabidopsis gene identified by genome sequencing, ZIP4, is induced in both shoots and roots of zinc-limited plants. Thus, ZIP4 may transport zinc intracellularly or between plant tissues. These ZIP proteins define a family of metal ion transporters that are found in plants, protozoa, fungi, invertebrates, and vertebrates, making it now possible to address questions of metal ion accumulation and homeostasis in diverse organisms.

Multifactor Explanations of Asset Pricing Anomalies

Abstract: Previous work shows that average returns on common stocks are related to firm characteristics like size, earnings/price, cashflow/price, book-to-market equity, past sales growth, long-term past return, and short term past return. Because these patterns in average returns apparently are not explained by the CAPM, they are called anomalies. We find that, except for the continuation of short-term returns, the anomalies largely disappear in a three-factor model. Our results are consistent with rational ICAPM or APT asset pricing, but we also consider irrational pricing and data problems as possible explanations.

Trauma and posttraumatic stress disorder in severe mental illness.

Abstract: This research assessed the lifetime prevalence of traumatic events and current posttraumatic stress disorder (PTSD) in 275 patients with severe mental illness (e.g., schizophrenia and bipolar disorder) receiving public mental health services in Concord and Manchester, New Hampshire, and Baltimore, Maryland. Lifetime exposure to traumatic events was high, with 98% of the sample reporting exposure to at least 1 traumatic event. The rate of PTSD in our sample was 43%, but only 3 of 119 patients with PTSD (2%) had this diagnosis in their charts. PTSD was predicted most strongly by the number of different types of trauma, followed by childhood sexual abuse. The findings suggest that PTSD is a common comorbid disorder in severe mental illness that is frequently overlooked in mental health settings. Language: en

Review of Integrated Mental Health and Substance Abuse Treatment for Patients With Dual Disorders

Abstract: Patients with severe mental disorders such as schizophrenia and co-occurring substance use disorders traditionally received treatments for their two disorders from two different sets of clinicians in parallel treatment systems. Dissatisfaction with this clinical tradition led to the development of integrated treatment models in which the same clinicians or teams of clinicians provide substance abuse treatment and mental health treatment in a coordinated fashion. We reviewed 36 research studies on the effectiveness of integrated treatment for dually diagnosed patients. Studies of adding dual-disorders groups to traditional services, studies of intensive integrated treatments in controlled settings, and studies of demonstration projects have thus far yielded disappointing results. On the other hand, 10 recent studies of comprehensive, integrated outpatient treatment programs provide encouraging evidence of the programs' potential to engage dually diagnosed patients in services and to help them reduce substance abuse and attain remission. Outcomes related to hospital use, psychiatric symptoms, and other domains are less consistent. Several program features appear to be associated with effectiveness: assertive outreach, case management, and a longitudinal, stage-wise, motivational approach to substance abuse treatment. Given the magnitude and severity of the problem of dual disorders, more controlled research on integrated treatment is needed.

Empirically Supported Couple and Family Interventions for Marital Distress and Adult Mental Health Problems

Abstract: This article evaluates the efficacy, effectiveness, and clinical significance of empirically supported couple and family interventions for treating marital distress and individual adult disorders, including anxiety disorders, depression, sexual dysfunctions, alcoholism and problem drinking, and schizophrenia. In addition to consideration of different theoretical approaches to treating these disorders, different ways of including a partner or family in treatment are highlighted: (a) partner-family-assisted interventions, (b) disorder-specific partner-family interventions, and (c) more general couple-family therapy. Findings across diagnostic groups and issues involved in applying efficacy criteria to these populations are discussed.

Information Retrieval: Algorithms and Heuristics

Abstract: List of Figures. Preface. 1. Introduction. 2. Retrieval Strategies. 3. Retrieval Utilities. 4. Efficiency Issues pertaining to Sequential IR Systems. 5. Integrating Structured Data and Text. 6. Parallel Information Retrieval Systems. 7. Distributed Information Retrieval. 8. The Text Retrieval Conference (TREC). 9. Future Directions. References.

What Determines Individual Trade Policy Preferences

Abstract: This paper provides new evidence on the determinants of individual trade policy preferences using an individual-level data set identifying both stated trade policy preferences and potential trade exposure through several channels for the United States in 1992 There are two main empirical results First, we find that factor type dominates industry of employment in explaining support for trade barriers This result is consistent with a Heckscher-Ohlin model of the United States in which the country is well endowed with skilled labor relative to the rest of the world The result suggests that there is high intersectoral labor mobility in the United States over the time horizons relevant to individuals when evaluating trade policy Second, we find that home ownership also matters for individuals' trade policy preferences Independent of factor type, home ownership in counties with a manufacturing mix concentrated in comparative disadvantage industries is strongly correlated with support for trade barriers This finding suggests that in addition to current factor incomes driving preferences as in standard trade models, in reality preferences also depend on asset values To the extent that trade policy is like other government policies which affect citizens by changing relative product prices, our findings have implications for how individuals form preferences over a wide range of economic policies

A Single Nucleotide Polymorphism in the Matrix Metalloproteinase-1 Promoter Creates an Ets Binding Site and Augments Transcription

Abstract: Matrix metalloproteinases (MMPs) facilitate cellular invasion by degrading the extracellular matrix, and their regulation is partially dependent on transcription. Binding sites for members of the Ets family of transcription factors are present within MMP promoters and are potent positive regulators. We report a single nucleotide polymorphism at -1607 bp in the MMP-1 promoter, where an additional guanine (G) creates an Ets binding site, 5′-GGA-3′. This polymorphism displays significantly higher transcription in normal fibroblasts and in melanoma cells than the 1 G polymorphism, and it binds substantially more nuclear extract and recombinant ETS-1. Analysis of control DNAs from the Center d'Etude du Polymorphisme Humain pedigrees reveals that this polymorphism is not a mutation, with a frequency of the 2 G polymorphism at 30%. In contrast, in eight tumor cell lines, this frequency increased to 62.5% ( P < 0.0001). Thus, this MMP-1 polymorphism contributes to increased transcription, and cells expressing the 2 G polymorphism may provide a mechanism for more aggressive matrix degradation, thereby facilitating cancer progression.

Overexpression of glyoxalase-I in bovine endothelial cells inhibits intracellular advanced glycation endproduct formation and prevents hyperglycemia-induced increases in macromolecular endocytosis.

Abstract: Methylglyoxal (MG), a dicarbonyl compound produced by the fragmentation of triose phosphates, forms advanced glycation endproducts (AGEs) in vitro. Glyoxalase-I catalyzes the conversion of MG to S-D-lactoylglutathione, which in turn is converted to D-lactate by glyoxalase-II. To evaluate directly the effect of glyoxalase-I activity on intracellular AGE formation, GM7373 endothelial cells that stably express human glyoxalase-I were generated. Glyoxalase-I activity in these cells was increased 28-fold compared to neo-transfected control cells (21.80+/-0.1 vs. 0. 76+/-0.02 micromol/min/mg protein, n = 3, P 10-fold (18.9+/-3.2 vs. 18.4+/- 5.8, n = 3, P = NS, and 107.1+/-9.0 vs. 9.4+/-0 pmol/10(6) cells, n = 3, P < 0.001, respectively). After exposure to 30 mM glucose, intracellular AGE formation in neo cells was increased 13.6-fold (2.58+/-0.15 vs. 0.19+/-0.03 total absorbance units, n = 3, P < 0.001). Concomitant with increased intracellular AGEs, macromolecular endocytosis by these cells was increased 2.2-fold. Overexpression of glyoxalase-I completely prevented both hyperglycemia-induced AGE formation and increased macromolecular endocytosis.

Thermodynamic constraints on nitrogen transformations and other biogeochemical processes at soil-stream interfaces

Abstract: There is much interest in biogeochemical processes that occur at the interface between soils and streams since, at the scale of landscapes, these habitats may function as control points for fluxes of nitrogen (N) and other nutrients from terrestrial to aquatic ecosystems. Here we examine whether a thermodynamic perspective can enhance our mechanistic and predictive understanding of the biogeochemical function of soil-stream interfaces, by considering how microbial communities interact with variations in supplies of electron donors and acceptors. Over a two-year period we analyzed >1400 individual samples of subsurface waters from networks of sample wells in riparian wetlands along Smith Creek, a first-order stream draining a mixed forested-agricultural landscape in southwestern Michigan, USA. We focused on areas where soil water and ground water emerged into the stream, and where we could characterize subsurface flow paths by measures of hydraulic head and/or by in situ additions of hydrologic tracers. We found strong support for the idea that the biogeochemical function of soil-stream interfaces is a predictable outcome of the interaction between microbial communities and supplies of electron donors and acceptors. Variations in key electron donors and acceptors (NO 3 - , N 2 O, NH 4 + , SO 4 2- , CH 4 , and dissolved organic carbon [DOC]) closely followed predictions from thermodynamic theory. Transformations of N and other elements resulted from the response of microbial communities to two dominant hydrologic flow paths: (1) horizontal flow of shallow subsurface waters with high levels of electron donors (i.e., DOC, CH 4 , and NH 4 + ), and (2) near-stream vertical upwelling of deep subsurface waters with high levels of energetically favorable electron acceptors (i.e., NO 3 - , N 2 O, and SO 4 2- ). Our results support the popular notion that soil-stream interfaces can possess strong potential for removing dissolved N by denitrification. Yet in contrast to prevailing ideas, we found that denitrification did not consume all NO 3 - that reached the soil-stream interface via subsurface flow paths. Analyses of subsurface N chemistry and natural abundances of δ 15 N in NO 3 - and NH 4 + suggested a narrow near-stream region as functionally the most important location for NO 3 - consumption by denitrification. This region was characterized by high throughput of terrestrially derived water, by accumulation of dissolved NO 3 - and N 2 O, and by low levels of DOC. Field experiments supported our hypothesis that the sustained ability for removal of dissolved NO 3 - and N 2 O should be limited by supplies of oxidizable carbon via shallow flowpaths. In situ additions of acetate, succinate, and propionate induced rates of NO 3 - removal (∼1.8 g N.m -2 .d -1 ) that were orders of magnitude greater than typically reported from riparian habitats. We propose that the immediate near-stream region may be especially important for determining the landscape-level function of many riparian wetlands. Management efforts to optimize the removal of NO 3 - by denitrification ought to consider promoting natural inputs of oxidizable carbon to this near-stream region.

Program fidelity in assertive community treatment: development and use of a measure.

Abstract: Assertive community treatment (ACT) is a complex community-based service approach to helping people with severe mental disorders live successfully in the community. Effective replication of the model and research on critical elements require explicit criteria and measurement. A measure of program fidelity to ACT and the results of its application to fifty diverse programs are presented.

ExoY, an adenylate cyclase secreted by the Pseudomonas aeruginosa type III system.

Abstract: The exoenzyme S regulon is a set of coordinately regulated virulence genes of Pseudomonas aeruginosa. Proteins encoded by the regulon include a type III secretion and translocation apparatus, regulators of gene expression, and effector proteins. The effector proteins include two enzymes with ADP-ribosyltransferase activity (ExoS and ExoT) and an acute cytotoxin (ExoU). In this study, we identified ExoY as a fourth effector protein of the regulon. ExoY is homologous to the extracellular adenylate cyclases of Bordetella pertussis (CyaA) and Bacillus anthracis (EF). The homology among the three adenylate cyclases is limited to two short regions, one of which possesses an ATP-binding motif. In assays for adenylate cyclase activity, recombinant ExoY (rExoY) catalyzed the formation of cAMP with a specific activity similar to the basal activity of CyaA. In contrast to CyaA and EF, rExoY activity was not stimulated or activated by calmodulin. A 500-fold stimulation of activity was detected following the addition of a cytosolic extract from Chinese hamster ovary (CHO) cells. These results indicate that a eukaryotic factor, distinct from calmodulin, enhances rExoY catalysis. Site-directed mutagenesis of residues within the putative active site of ExoY abolished adenylate cyclase activity. Infection of CHO cells with ExoY-producing strains of P. aeruginosa resulted in the intracellular accumulation of cAMP. cAMP accumulation within CHO cells depended on an intact type III translocation apparatus, demonstrating that ExoY is directly translocated into the eukaryotic cytosol.

Effects of fragmentation and invasion on native ant communities in coastal southern california

Abstract: We investigated the roles of habitat fragmentation and the invasion of an exotic species on the structure of ground-foraging ant communities in 40 scrub habitat fragments in coastal southern California. In particular, we asked: how do fragment age, fragment size, amount of urban edge, percentage of native vegetation, degree of isolation, and the relative abundance of an exotic species, the Argentine ant (Linepithema humile) affect native ants? Within these fragments, Argentine ants were more abundant near developed edges and in areas dominated by exotic vegetation. The number of native ground-foraging ant species at any point declined from an average of >7 to <2 species in the presence of the Argentine ant. Among fragments, a stepwise multiple regression revealed that the abundance of Argentine ants, the size of the fragment, and the number of years since it was isolated from larger continuous areas of scrub habitat best predict the number of remaining native ant species. The Argentine ant was found in every fragment surveyed as well as around the edges of larger unfragmented areas. Fragments had fewer native ant species than similar-sized plots within large unfragmented areas, and fragments with Argentine ant-free refugia had more native ant species than those without refugia. The relative vulnerability of native ants to habitat fragmentation and the subsequent presence of Argentine ants vary among species. The most sensitive species include army ants (Neivamyrmex spp.) and harvester ants (genera Messor and Pogonomyrmex), both of which are important to ecosystem-level processes. Our surveys suggest that the Argentine ant is widespread in fragmented coastal scrub habitats in southern California and strongly affects native ant communities.

Intraoperative brain shift and deformation: a quantitative analysis of cortical displacement in 28 cases.

Abstract: Objective A quantitative analysis of intraoperative cortical shift and deformation was performed to gain a better understanding of the nature and extent of this problem and the resultant loss of spatial accuracy in surgical procedures coregistered to preoperative imaging studies. Methods Three-dimensional feature tracking and two-dimensional image analysis of the cortical surface were used to quantify the observed motion. Data acquisition was facilitated by a ceiling-mounted robotic platform, which provided a number of precision tracking capabilities. The patient's head position and the size and orientation of the craniotomy were recorded at the start of surgery. Error analysis demonstrated that the surface displacement measuring methodology was accurate to 1 to 2 mm. Statistical tests were performed to examine correlations between the amount of displacement and the type of surgery, the nature of the cranial opening, the region of the brain involved, the duration of surgery, and the degree of invasiveness. Results The results showed that a displacement of an average of 1 cm occurred, with the dominant directional component being associated with gravity. The mean displacement was determined to be independent of the size and orientation of the cranial opening. Conclusion These data suggest that loss of spatial registration with preoperative images is gravity-dominated and of sufficient extent that attention to errors resulting from misregistration during the course of surgery is warranted.

Anhedonia, Positive and Negative Affect, and Social Functioning in Schizophrenia

Abstract: This study examines the relationship between anhedonia and the trait dimensions of positive affect (PA) and negative affect (NA) in schizophrenia. The relationship between poor social functioning in schizophrenia and these individual differences in affectivity is also examined. Schizophrenia outpatients (n = 37) and normal controls (n = 15) were assessed at a baseline evaluation and again approximately 90 days later. Consistent with the hypothesized decrease in hedonic capacity in schizophrenia, patients reported significantly greater physical and social anhedonia and less PA than controls. However, the schizophrenia group also reported significantly greater NA and social anxiety than did controls. In support of the dispositional view of these individual differences in affectivity, trait measures demonstrated test-retest reliability, and group differences between the schizophrenia group and controls were stable over the 90-day followup period. Within the schizophrenia group, physical and social anhedonia were comparably negatively correlated with trait PA; however, social but not physical anhedonia was significantly positively correlated with NA and social anxiety. Poor social functioning in the schizophrenia group was associated with greater physical and social anhedonia and greater NA and social anxiety. Alternatively, greater trait PA was related to better social functioning. These findings indicate that schizophrenia is characterized by both low PA and elevated NA and that these affective characteristics are a stable feature of the illness. The results also suggest important links between affect and social functioning in schizophrenia.

Influence of Patient Preferences and Local Health System Characteristics on the Place of Death

Abstract: OBJECTIVE: To examine the degree to which variation in place of death is explained by differences in the characteristics of patients, including preferences for dying at home, and by differences in the characteristics of local health systems. DESIGN: We drew on a clinically rich database to carry out a prospective study using data from the observational phase of the Study to Understand Prognoses and Preferences for Outcomes and Risks of Treatments (SUPPORT component). We used administrative databases for the Medicare program to carry out a national cross-sectional analysis of Medicare enrollees place of death (Medicare component). SETTING: Five teaching hospitals (SUPPORT); All U.S. Hospital Referral Regions (Medicare). STUDY POPULATIONS: Patients dying after the enrollment hospitalization in the observational phase of SUPPORT for whom place of death and preferences were known. Medicare beneficiaries who died in 1992 or 1993. MAIN OUTCOME MEASURES: Place of death (hospital vs non-hospital). RESULTS: In SUPPORT, most patients expressed a preference for dying at home, yet most died in the hospital. The percent of SUPPORT patients dying in-hospital varied by greater than 2-fold across the five SUPPORT sites (29 to 66%). For Medicare beneficiaries, the percent dying in-hospital varied from 23 to 54% across U.S. Hospital Referral Regions (HRRs). In SUPPORT, variations in place of death across site were not explained by sociodemographic or clinical characteristics or patient preferences. Patient level (SUPPORT) and national cross-sectional (Medicare) multivariate models gave consistent results. The risk of in-hospital death was increased for residents of regions with greater hospital bed availability and use; the risk of in-hospital death was decreased in regions with greater nursing home and hospice availability and use. Measures of hospital bed availability and use were the most powerful predictors of place of death across HRRs. CONCLUSIONS: Whether people die in the hospital or not is powerfully influenced by characteristics of the local health system but not by patient preferences or other patient characteristics. These findings may explain the failure of the SUPPORT intervention to alter care patterns for seriously ill and dying patients. Reforming the care of dying patients may require modification of local resource availability and provider routines.