Showing papers by "Dartmouth College published in 1992"

Relationships between Providers and Users of Market Research: The Dynamics of Trust within and between Organizations:

Abstract: The authors investigate the role of trust between knowledge users and knowledge providers. The kind of knowledge of special concern is formal market research. Users include marketing and nonmarketi...

The Changing Role of Marketing in the Corporation

Abstract: New organization forms, including strategic partnerships and networks, are replacing simple market-based transactions and traditional bureaucratic hierarchical organizations. The historical marketi...

A 39-kDa protein on activated helper T cells binds CD40 and transduces the signal for cognate activation of B cells

Abstract: CD40 is a B-cell surface molecule that has been shown to induce B-cell growth upon ligation with monoclonal antibodies. This report shows that triggering via CD40 is essential for the activation of resting B cells by helper T cells (Th). A soluble fusion protein of CD40 and human immunoglobulin, CD40-Ig, inhibited the induction of B-cell cycle entry, proliferation, and differentiation by activated Th1 and Th2. The ligand for CD40 was identified as a 39-kDa membrane protein that was selectively expressed on activated Th. A monoclonal antibody specific for the 39-kDa protein inhibited CD40-Ig binding and also inhibited the activation of B cells by Th. These data indicate that the 39-kDa membrane protein expressed on activated Th is a binding protein for CD40 and functions to transduce the signal for Th-dependent B-cell activation.

Sulfur Emissions to the Atmosphere from Natural Sources

Abstract: Emissions of sulfur gases from both natural and anthropogenic sources strongly influence the chemistry of the atmosphere. To assess the relative importance of these sources we have combined the measurements of sulfur gases and fluxes during the past decade to create a global emission inventory. The inventory, which is divided into 12 latitude belts, takes into account the seasonal dependence of sulfur emissions from biogenic sources. The total emissions of sulfur gases from natural sources are approximately 0.79 Tmol S/a. These emissions are 16% of the total sulfur emissions in the Northern Hemisphere and 58% in the Southern Hemisphere. The inventory clearly shows the impact of anthropogenic sulfur emissions in the region between 35° and 50°N.

The accuracy of Medicare's hospital claims data: progress has been made, but problems remain.

Abstract: BACKGROUND. Health care databases provide a widely used source of data for health care research, but their accuracy remains uncertain. We analyzed data from the 1985 National DRG Validation Study, which carefully reabstracted and reassigned ICD-9-CM diagnosis and procedure codes from a national sample of 7050 medical records, to determine whether coding accuracy had improved since the Institute of Medicine studies of the 1970s and to assess the current coding accuracy of specific diagnoses and procedures. METHODS. We defined agreement as the proportion of all reabstracted records that had the same principal diagnosis or procedure coded on both the original (hospital) record and on the reabstracted record. We also evaluated coding accuracy in 1985 using the concepts of diagnostic test evaluation. RESULTS. Overall, the percentage of agreement between the principal diagnosis on the reabstracted record and the original hospital record, when analyzed at the third digit, improved from 73.2% in 1977 to 78.2% in ...

Top team deterioration as part of the downward spiral of large corporate bankruptcies

Abstract: This exploratory study of 57 large bankruptcies and 57 matched survivors examined the top management team TMT characteristics associated with major corporate failure. Prior research was used to guide selection of specific team characteristics for study. Not only did the failing firms show significant annual, or cross-sectional, divergence from survivors on several indicators of TMT composition, but also those divergences became more pronounced, even accelerating, over the last five years of the bankrupts' lives. The results thus suggest that deterioration of the top management team is a central element of the downward spiral of large corporate failures. Based upon a limited test of causality, the authors propose that a two-way process is at work: 1 team deficiencies bring about or aggravate corporate deterioration, either through strategic errors or stakeholder uneasiness with the flawed team; and 2 corporate deterioration brings about team deterioration, through a combination of voluntary departures, scapegoating, and limited resources for attracting new executive talent.

Variations in Resource Utilization Among Medical Specialties and Systems of Care: Results From the Medical Outcomes Study

Abstract: Objective. —To examine whether specialty and system of care exert independent effects on resource utilization. Study Design. —Cross-sectional analysis of just over 20 000 patients (≥18 years of age) who visited providers' offices during 9-day periods in 1986. Patient- and physician-provided information was obtained by self-administered questionnaires. Setting. —Offices of 349 physicians practicing family medicine, internal medicine, endocrinology, and cardiology within health maintenance organizations, large multispecialty groups, and solo practices or small single-specialty group practices in three major US cities. Outcome Measures. —Indicators of the intensity of resource utilization were examined among four medical specialties (family practice, general internal medicine, cardiology, and endocrinology) and five systems of care (health maintenance organization, multispecialty group—fee-for-service, multispecialty group—prepaid; solo practice and single-specialty group—fee-for-service, and solo practice and single-specialty group—prepaid) before and after controlling for the mix of patients seen in these offices. The indicators of resource utilization were hospitalizations, annual office visits, prescription drugs, and common tests and procedures, with rates estimated on both a per-visit and per-year basis. Results. —Variation in patient mix was a major determinant of the large variations in resource use. However, increased utilization was also independently related to specialty (cardiology and endocrinology), fee-for-service payment plan, and solo and single-specialty group practice arrangements. After adjusting for patient mix, solo practice/single-specialty groups—fee-for-service had 41% more hospitalizations than health maintenance organizations. General internists had utilization rates somewhat greater than family physicians on some indicators. Conclusion. —Although variations in patient mix should be a major determinant of variations in resource use, the independent effects of specialty training, payment system, and practice organization on utilization rates need further explication. The 2- and 4-year outcomes now being analyzed will provide information critical to interpretation of the variations reported herein. ( JAMA . 1992;267:1624-1630)

Telephone care as a substitute for routine clinic follow-up.

Abstract: Design. —Randomized trial. Setting. —A primary care clinic. Patients. —Four hundred ninety-seven men aged 54 years or older. Objective. —We examined the hypothesis that substituting clinician-initiated telephone calls (telephone care) for some clinic visits would reduce medical care utilization without adversely affecting patient health. Intervention. —Clinicians were asked to double their recommended interval for face-to-face follow-up and schedule three intervening telephone contacts; for control patients, the follow-up interval recommended by their clinician was unchanged. Main Outcome Measures. —Use of medical services and health status. Results. —During the 2-year follow-up period, 7% of patients withdrew or became unavailable. Telephone-care patients had fewer total clinic visits, scheduled and unscheduled, than usual-care patients (19%, P P =.006), fewer admissions, and shorter stays in the hospital (28% fewer total hospital days, P =.005), and 41% fewer intensive care unit days ( P =.03). Estimated total expenditures for telephone care were 28% less per patient for the 2 years ($1656, P =.004). For the subgroup of patients with fair or poor overall health at the beginning of the study (n= 180), savings were somewhat greater ($1976, P =.01). In this subgroup, improvement in physical function from baseline ( P =.02) and a possible reduction in mortality ( P =.06) were also observed. Conclusion. —We conclude that substituting telephone care for selected clinic visits significantly reduces utilization of medical services. For more severely ill patients, the increased contact made possible by telephone care may also improve health status and reduce mortality. ( JAMA . 1992;267:1788-1793)

Toward a Theoretical Framework of Repatriation Adjustment

Abstract: Although the increased internationalization of business has brought greater scholarly attention to the issue of adjustment to overseas assignments, comparatively little research activity has been paid to the topic of adjustment back to the home country and home office—repatriation adjustment. In this article we argue that repatriation adjustment is sufficiently different from other forms of work adjustment (e.g., domestic relocation and expatriate assignments) to warrant separate theoretical and empirical investigation. To facilitate this, we propose an initial theoretical framework and set of derived propositions to guide and spark future research on this topic.

Social support and depressive symptoms in the elderly.

Abstract: The purpose of this study was to examine the effect of characteristics of social networks and support on depressive symptoms in the elderly. The subjects were 1,962 noninstitutionalized persons 65 years and older from the New Haven Establishment of Populations for Epidemiologic Study of the Elderly in 1982, who were available to give a complete follow-up interview in 1985. Baseline depression, functional disability in 1982, and any change in disability by 1985 were considered as additional influences on 1985 depression, requiring adjustment along with sociodemographic variables. Multiple regression procedures were used to simultaneously examine the variables. Baseline depression, functional disability, and change in functional disability made the largest contribution to explaining the variance in depression. Among the social support and network characteristics, loss of a spouse, adequacy of emotional support, and its change during 1982-1985 made the largest contributions. Other significant characteristics in relative order of magnitude of effect, based on contrast tests, included tangible support adequacy and its change, loss of a confidant between 1982 and 1985, number of children making weekly visits and change in this number by 1985, and the absence of a confidant in both 1982 and 1985. For mental health outcomes, these findings emphasize the need to consider specific dimensions of social support and networks rather than global measures.

Immunohistochemical staining for transforming growth factor beta 1 associates with disease progression in human breast cancer.

Abstract: The transforming growth factor beta s (TGF-beta) comprise a family of M(r) 25,000 pluripotent growth factors which have been implicated in the development and progression of human breast cancer. Conflicting data suggest that TGF-beta has the potential to either inhibit or promote the progression of mammary neoplasia. We therefore examined a pathological library of malignant breast biopsy specimens to determine the prevalence and distribution of immunoreactivity with antibodies specific for the three mammalian isoforms of TGF-beta (beta 1, beta 2, and beta 3). We found that intense staining for TGF-beta 1 was positively associated with rate of disease progression, and that this was independent of age, stage, nodal status, or estrogen receptor status (P = 0.009).

Actin-dependent organelle movement in squid axoplasm

Abstract: Studies of organelle movement in axoplasm extruded from the squid giant axon have led to the basic discoveries of microtubule-dependent organelle motility and the characterization of the microtubule-based motor proteins kinesin and cytoplasmic dynein. Rapid organelle movement in higher animal cells, especially in neurons, is considered to be microtubule-based. The role of actin filaments, which are also abundant in axonal cytoplasm, has remained unclear. The inhibition of organelle movement in axoplasm by actin-binding proteins such as DNase I, gelsolin and synapsin I has been attributed to their ability to disorganize the microtubule domains where most of the actin-filaments are located. Here we provide evidence of a new type of organelle movement in squid axoplasm which is independent of both microtubules and microtubule-based motors. This movement is ATP-dependent, unidirectional, actin-dependent, and probably generated by a myosin-like motor. These results demonstrate that an actomyosin-like mechanism can be directly involved in the generation of rapid organelle transport in nerve cells.

Isolation and characterization of RAT1: an essential gene of Saccharomyces cerevisiae required for the efficient nucleocytoplasmic trafficking of mRNA.

Abstract: We have combined techniques of genetics and histochemistry to identify genes required for the nucleocytoplasmic export of mRNA in the budding yeast Saccharomyces cerevisiae. We adapted in situ hybridization using a digoxigenin-labeled oligo(dT)50 probe to localize poly(A)+ RNA in fixed yeast cells and used yeast strains carrying the rna1-1 mutation to develop an assay. The rna1-1 mutation is the only previously described mutation that causes defects in mRNA export. As visualized with this RNA localization assay, rna1-1 strains accumulated poly(A)+ RNA at the nuclear periphery at the nonpermissive temperature. This was in contrast to the RNA localization pattern of wild-type cells or rna1-1 cells grown at permissive temperature. Wild-type cells showed bright uniform cytoplasmic staining with little detectable RNA in the nuclei. We used this RNA localization assay to screen a bank of temperature-sensitive yeast strains for mutants with inducible defects in mRNA trafficking. Strains identified in this manner are designated RAT mutants for ribonucleic acid trafficking. The rat1-1 allele conferred temperature-sensitive accumulation of poly(A)+ RNA in one to several intranuclear spots that appear to lie at the nuclear periphery. RNA processing was unaffected in rat1-1 strains, except for an inducible defect in trimming the 5' end of the 5.8S rRNA. The wild-type RAT1 gene was cloned by complementation; it encodes an essential 116-kD protein with regions of homology to the protein encoded by SEP1 (also known as DST2, XRN1, KEM1, and RAR5). Sep1p is a nucleic acid binding protein, a 5'----3' exonuclease, and catalyzes DNA strand transfer reactions in vitro. We discuss the possible significance of the Rat1p/Sep1p homology for RNA trafficking. We also discuss the potential of this RNA localization assay to identify genes involved in nuclear structure and RNA metabolism.

Ego Mechanisms of Defense: A Guide for Clinicians and Researchers

Abstract: Clinical Applications. The historical origins of Sigmund Freud's concept of the mechanisms of defense. The place of defense mechanisms in diagnostic formulation and in modern clinical practice. The need for a uniform nomenclature for defenses. The clinical management of immature defenses in the treatment of individuals with personality disorders. Empirical Studies. The struggle for empirical assessment of defenses. Empirical evidence that defensive styles are independent of environmental influence. An empirical study of defensive styles: the Defense Style Questionnaire. A cross-validation of two methods of investigating defenses. Toward reliability in identifying ego defenses: clinical techniques. An approach to evaluating adolescent ego defense mechanisms using clinical interviews. What do cross-sectional measures of defense mechanisms predict? A Q-sort approach to identifying defenses. Appendixes. Seven Assessment Schemes for Defense Mechanisms. DSM-III-R glossary of defense mechanisms. Meissner's glossary of defenses. Vaillant's glossary of defenses. Perry's Defense Mechanism Rating Scale. Ego Defense Mechanisms Manual (Jacobson et al.). Bond's Defense Style Questionnaire (DSQ). Vaillant's modification of the Haan Q-sort.

Antecedents to Commitment to A Parent Company and A Foreign Operation

Abstract: This study of 321 American managers on international assignment in Pacific Rim or European countries assessed theoretically and empirically the extent to which various personal, job, organizational...

The intelligent enterprise a new paradigm

Abstract: Executive Overview The development and use of technology for services—whether in the “service industries” or in manufacturing—may be the key to future wealth and productivity in advanced industrial countries. Quinn believes that the organization of enterprises and effective strategies will depend more on the development and deployment of intellectual resources than on the management of physical assets. In this article he discusses the concept of disaggregating corporate activities into manageable intellectual clusters—called service activities.

Homozygous deletions within human chromosome band 9p21 in melanoma.

Abstract: Genetic studies have implicated the early involvement of a gene on chromosome arm 9p in the development of cutaneous melanoma. We have performed loss-of-heterozygosity studies to confirm these original findings and identify the most frequently rearranged or deleted region of 9p. Eight markers were analyzed, including (from 9pter to proximal 9q) D9S33, the beta-interferon (IFNB1) locus, the alpha-interferon (IFNA) gene cluster, D9S126, D9S3, D9S19, the glycoprotein 4 beta-galactosyltransferase (GGTB2) gene, and the argininosuccinate synthetase pseudogene 3 (ASSP3). Two or more of these loci were found to be hemizygously reduced in 12 of 14 (86%) informative metastatic melanoma tumor and cell line DNAs, and homozygous deletions of the marker D9S126 were observed in 2 of 20 (10%) melanoma cell lines. These findings have resulted in the identification of a small critical region of 2-3 megabases on 9p21 in which a putative melanoma tumor-suppressor gene appears likely to reside. Several 9p candidate genes, including IFNB1, the IFNA gene cluster, GGTB2, and the tyrosinase-related protein (TYRP) locus, have all been eliminated as potential targets because they are located outside of the homozygously deleted regions.

Risk of subsequent basal cell carcinoma and squamous cell carcinoma of the skin among patients with prior skin cancer. Skin Cancer Prevention Study Group.

Abstract: Objective. —The primary aims of this study were to assess risk of subsequent basal and squamous cell skin cancer among patients with a prior history of these tumors and to examine these risks in relation to patient characteristics and life-style factors. Design. —Follow-up of participants in a randomized trial of betacarotene as a possible skin cancer preventive agent. Setting. —Clinical centers in Los Angeles, Calif, San Francisco, Calif, Minneapolis, Minn, and Hanover, NH. Participants. —Patients (n=1805) who were diagnosed as having a basal or squamous cell skin cancer between January 1980 and February 1986 and were free of skin cancer at study entry. Main Outcome Measure. —Time from study entry to first new occurrence of basal and squamous cell skin cancer. Results. —The estimated risk of developing one or more new skin cancers was 35% at 3 years and 50% at 5 years. New skin cancers tended to be of the same cell type as the previous skin cancers. For both basal and squamous cell skin cancer, risk was higher among patients who were male, were over the age of 60 years, had more prior skin cancers, had severe actinic skin damage, or who burned easily with sun exposure. Compared with those who had never smoked, the rate of subsequent squamous cell skin cancer was higher among current smokers (rate ratio, 2.01; 95% confidence interval,1.21 to 3.34) and former smokers (rate ratio,1.62; 95% confidence interval, 1.07 to 2.47) and increased with both duration and amount smoked. There was no clear relationship between smoking and basal cell skin cancer; the rate appeared lower among heavy smokers but was unrelated to duration of smoking. Conclusions. —Persons with a prior nonmelanoma skin cancer had a substantial 5-year risk of developing another tumor of the same histologic type. Number of previous skin cancers, solar damage, and skin sensitivity to sun exposure were particularly related to this risk. The increased risk of squamous cell skin cancer associated with cigarette smoking merits further study. ( JAMA . 1992;267:3305-3310)

The Environment and Internal Organization of Multinational Enterprises

Abstract: Multiple sources of external authority and multiple denominations of value are two distinguishing aspects of the environment faced by multinational enterprises (MNEs). After defining the MNE as an organizational form, we examine the research implications of these two environmental influences on four aspects of MNE internal organization: modes of entry abroad, configuration of activities, coordination and control, and competitive strategy. We present general propositions to guide future research and argue that multiple sources of authority and multiple denominations of value require cross-disciplinary research efforts in order to fully understand the MNE as an organizational form.

Modeling Pack Ice as a Cavitating Fluid

Abstract: Polar ocean circulation is influenced by fluxes of salt and freshwater at the surface as ice freeze in one location, is transported by the winds and currents, and melts again elsewhere. The motion of sea ice, moreover, is strongly affected by internal stresses that arise from the mechanical strength of the ice cover. A simple sea-ice dynamics model, allowing these effects to be included in large-scale climate studies, is presented. In this model a cavitating fluid behaviour is assumed whereby the ice pack does not resist divergence or shear, but does resist convergence. While less realistic than other rheologies that include shear strength, this assumption has certain advantages for long-term climate studies. First, it allows a simple and efficient numerical scheme, in both rectangular and spherical coordinates, which as developed here along with a generation to include shear strength via the Mohr-Coulomb failure criteria. Second, realistic ice transport is maintained, even when the model is driv...

The origins of DNA breaks: a consequence of DNA damage, DNA repair, or apoptosis?

Abstract: DNA breaks can arise from many sources after incubation of cells with toxic agents. Very few agents break DNA directly, rather most breaks occur as a result of metabolic participation by the cell, such as during attempts to repair the damage. It is now realized that many DNA breaks arise as a consequence of steps in the pathway of cell death. Upon reanalyzing the methodology commonly used to detect DNA breaks, it is evident that many studies would not have observed DNA breaks associated with cell death. Frequently experimental conditions have been used that are extremely toxic to cells with the justification that the cells were still viable as measured by their ability to exclude dyes such as trypan blue. However, the DNA digestion associated with cell death by apoptosis occurs prior to changes in membrane integrity. Because the possibility of endogenous endonuclease activity was not realized, many studies may have inaccurately assumed that DNA breaks arose during, for example, inhibition of DNA repair or as intermediates in recombination. In light of the new understanding of apoptosis and the formation of DNA breaks as an early event in cell death, it is important to both reevaluate past conclusions and to ensure that future studies fully consider the breaks derived from the cytotoxicity of every agent under investigation.

Decentralized adaptive controller design for large-scale systems with higher order interconnections

Abstract: Decentralized robust adaptive controller designs for large-scale interconnected systems are investigated. Motivated by real mechanical systems, the authors consider a general representation of interconnections when the strength of the interconnections is bounded by a pth-order polynomial in states. This is in contrast to other studies which have made simpler assumptions about the strength of the interconnections. The authors investigate several scenarios as the control computations become more distributed until the controllers are completely decentralized. The possible bound of the interconnections is assumed to be known for the decentralized semiadaptive controller. Without the knowledge of these bounds, two adaptive controllers are designed: a decentralized adaptive controller with partially centralized compensation and a fully adaptive decentralized controller. >

Corrosion between the components of modular femoral hip prostheses.

Abstract: We studied the tapered interface between the head and the neck of 139 modular femoral components of hip prostheses which had been removed for a variety of reasons. In 91 the same alloy had been used for the head and the stem; none of them showed evidence of corrosion. In contrast, there was definite corrosion in 25 of the 48 prostheses in which the stem was of titanium alloy and the head of cobalt-chrome. This corrosion was time-dependent: no specimens were corroded after less than nine months in the body, but all which had been in place for more than 40 months were damaged. We discuss the factors which may influence the rate of these changes and present evidence that they were due to galvanically-accelerated crevice corrosion, which was undetected in previous laboratory testing of this type of prosthesis.