Showing papers by "Dartmouth College published in 1986"
TL;DR: The results demonstrate that user involvement in the development of information systems will enhance both system usage and the user's satisfaction with the system.
Abstract: "User involvement" in information system development is generally considered an important mechanism for improving system quality and ensuring successful system implementation. The common assumption that user involvement leads to system usage and/or information satisfaction is examined in a survey of 200 production managers. Alternative models exploring the causal ordering of the three variables are developed and tested via path analysis. The results demonstrate that user involvement in the development of information systems will enhance both system usage and the user's satisfaction with the system. Further, the study provides evidence that the user's satisfaction with the system will lead to greater system usage.
948 citations
TL;DR: In this article, the authors examined a theory of feedback-seeking in organizations and found that individuals are hypothesized to seek feedback on important issues and in new and uncertain situations, and the results support these hypotheses.
Abstract: This research examines a theory of feedback-seeking in organizations. Individuals are hypothesized to seek feedback on important issues and in new and uncertain situations. Results support these hy...
896 citations
TL;DR: The authors conclude that physical disabilities among the elderly do not appear to be a major threat to the validity of the CES-D scale and that the strong associations between physical and mental health should be rigorously investigated.
Abstract: The associations between depressive symptoms and functional disability and chronic conditions are examined in an elderly cohort of 2,806 noninstitutionalized men and women living in New Haven, Connecticut who were interviewed in 1982 as a part of the Yale Health and Aging Project. The aim is to explore several potential sources of invalidity in using the Center for Epidemiologic Studies-Depression scale (CES-D) to measure depressive symptoms in elderly populations. In particular, the authors are concerned with the possibility that prevalent physical illnesses and disabilities may cause the older person to report many somatic complaints, a major component of most measures of depressive symptomatology, and thereby inflate his or her CES-D score. Mean CES-D scores are 4.86 for those without any disabilities and range to 13.51 for those with major functional disabilities. However, physical disability is significantly associated with virtually every item on the CES-D scale not just those somatically-oriented items. The addition of functional disability to a multivariate model including age subfactor analysis of responses from this elderly sample produces results almost identical to those reported by earlier investigators who studied younger and middle-aged adults. The authors conclude that physical disabilities among the elderly do not appear to be a major threat to the validity of the CES-D scale and that the strong associations between physical and mental health should be rigorously investigated.
805 citations
TL;DR: In this article, the authors derived a supply price for public policy using a constrained maximization model, in which three sets of agents each have preferences over outcomes: organized interest groups offer campaign contributions to improve their own wealth, voters offer votes to obtain outcomes closer to their most preferred outcomes, and legislators seek both campaign contributions and votes to get reelection.
Abstract: This paper derives a supply price for public policy using a constrained maximization model. In the model, three sets of agents each have preferences over outcomes: organized interest groups offer campaign contributions to improve their own wealth, voters offer votes to obtain outcomes closer to their most preferred outcomes, and legislators seek both campaign contributions and votes to obtain reelection. A given legislator's supply price for policy is shown to depend on the productivity of his effort, as determined by committee assignments, priority and ability, and by the preferences of his unorganized constituency in the home district. Two extreme assumptions about the effectiveness of campaign spending in eliciting votes are used to illustrate the comparative statics properties of the model. The prediction of the model is that interest groups will, in general, seek out legislators whose voters are indifferent to the policy the interest group seeks. Thus, voters who do have preferences over policy are in effect represented, even though they are not organized.
663 citations
TL;DR: A meta-analysis of research investigating the effects of alcohol consumption and expectancy within the balanced-placebo design found that both alcohol and expectancy have significant, although heterogeneous effects on behavior.
Abstract: A meta-analysis was conducted on research investigating the effects of alcohol consumption and expectancy within the balanced-placebo design. Preliminary results indicated that both alcohol and expectancy have significant, although heterogeneous effects on behavior. Subsequent analyses were conducted to determine the factors responsible for the heterogeneity of effects. At the highest level of analysis, alcohol expectancy had strong effects on relatively deviant social behaviors and minimal effects on nonsocial behaviors. Alcohol consumption showed the opposite pattern of effects. The principal effects associated with alcohol expectancy involved increased alcohol consumption and increased sexual arousal in response to erotic stimuli. On the other hand, alcohol consumption led to significant impairment of information processing and motor performance, induced a specific set of physical sensations, resulted in general improvements of mood, and tended to increase aggression. Finally, across all studies it was observed that alcohol consumption and expectancy interacted no more frequently than would be expected by chance. These results have implications for both the theories and methods of contemporary alcohol research.
520 citations
515 citations
TL;DR: In this paper, the authors examine when resource sharing is desirable and what its administrative implications are for strategic business units (SBUs) in the context of resource sharing among SBUs.
Abstract: Despite widespread resource sharing among strategic business units (SBUs), questions such as when resource sharing is desirable and what its administrative implications are have rarely been examine...
332 citations
TL;DR: Evidence is offered that defensive style provides an independent dimension of mental health, and the bleaker the childhood the stronger the association of maturity of defenses with adult mental health.
Abstract: • We empirically examined the validity of ego mechanisms of defense as an explanatory concept for psychological health in 307 middle-aged men who were prospectively followed up for 40 years. Assessed on the basis of a two-hour interview when the men were 47 years old, the maturity (health) of the men's defenses correlated highly with independently assessed outcome measures. Evidence is offered that defensive style provides an independent dimension of mental health. First, childhood variables significantly predicted midlife mental health but not midlife maturity of defenses. Second, the bleaker the childhood the stronger the association of maturity of defenses with adult mental health. Third, the Bond Defense Style Questionnaire, administered to 131 of the 307 men six to eight years after the interview, identified the same styles of defense that were identified earlier by clinical assessment.
318 citations
TL;DR: The immediate shock deficit reflects a deficit in association formation between contextual stimuli and shock rather than a difference in defensive behavioral topography and it appears that freezing is the dominant conditional response to shock-associated stimuli even though freezing is not unconditionally elicited by the shock itself.
318 citations
TL;DR: In this paper, the effect of batch steam explosion pretreatment on the rate of subsequent enzymatic hydrolysis of hybrid poplar wood was investigated and it was shown that steam explosion pre-treatment can be effective in increasing the pore surface area accessible to enzymes.
317 citations
TL;DR: In this article, the authors examined the effects of component commonality on optimal safety stock levels in a two-product, two-level inventory model, where the criterion is to minimize system safety stock subject to a service level constraint.
Abstract: We examine the effects of component commonality on optimal safety stock levels in a two-product, two-level inventory model. The criterion is to minimize system safety stock subject to a service level constraint. Although our model is specialized, its analysis provides insights not available in other multilevel inventory models.
TL;DR: In this article, the diagnosis and assessment of Asian-America ns is divided into three sections: (a) symptom expression, (b) therapist bias, (c) problems with the use of interpreters, and (d) use of clinical and personality tests.
Abstract: This article is divided into three sections. The first section concerns the diagnosis and assessment of Asian-America ns and covers the following issues: (a) symptom expression, (b) therapist bias, (c) problems with the use of interpreters, and (d) problems with the use of clinical and personality tests. The second section, on counseling and psychotherapy, is divided into three subsections: (a) client variables, (b) therapist variables, and (c) counseling process and outcome. The subsection on client variables covers such issues as the personality of Asian-America ns, language problems, the acculturation process, and counseling expectations. The subsection on therapist variables includes discussion of therapist bias, training bias, lack of intercultural skills, and culture-specific knowledge. The therapy process and outcome subsection reviews empirical studies, clinical case studies, and articles with treatment strategies and recommendations. Research issues as well as research recommendations for each of the areas reviewed are identified and discussed in the third section.
TL;DR: It is found that major targets were identified faster, and with fewer errors, when they were related than when unrelated, and an apparent absence (and possible reversal) of this effect for minor targets can be attributed to the prime's biasing effect on the target's stability.
Abstract: The cognitive processes underlying musical expectation were explored by measuring reaction time in a priming paradigm. Subjects made a speeded true/false decision about a target chord following a prime chord to which it was either closely or distantly related harmonically. Using a major/minor decision task in Experiment 1, we found that major targets were identified faster, and with fewer errors, when they were related than when unrelated. An apparent absence (and possible reversal) of this effect for minor targets can be attributed to the prime's biasing effect on the target's stability. In Experiments 2 and 3 we tested this hypothesis by employing an in-tune/out-of-tune decision for major and minor targets separately. Both major and minor in-tune targets were identified faster when related than when unrelated. We outline a spreading activation model which consists of a network of harmonic relations. Priming results from the indirect activation of chord nodes linked through the network.
TL;DR: In this article, the authors present evidence that nonlinear wave-wave interactions occur in type III solar radio bursts in the interplanetary medium, and three possible interpretations of these observations are considered: modulational instability, parametric decay of the parent Langmuir waves to daughter ion acoustic and Langmauir waves, and decay to daughter electromagnetic waves and ion acoustic waves.
Abstract: Evidence is presented that nonlinear wave-wave interactions occur in type III solar radio bursts. Intense, spiky Langmuir waves are observed to be driven by electron beams associated with type III solar radio bursts in the interplanetary medium. Bursts of 30-300 Hz (in the spacecraft frame) waves are often observed coincident in time with the most intense spikes of the Langmuir waves. These low-frequency waves appear to be long-wavelength ion acoustic waves, with wavenumber approximately equal to the beam resonant Langmuir wavenumber. Three possible interpretations of these observations are considered: modulational instability, parametric decay of the parent Langmuir waves to daughter ion acoustic and Langmuir waves, and decay to daughter electromagnetic waves and ion acoustic waves.
TL;DR: In this paper, data from responsibility-center managers reveal that greater budgetary participation contributes to managerial performance and attitudes in high-environmental-uncertainty situations but hampers performance and attitude in low-uniformity situations.
Abstract: Data from responsibility-center managers reveal that greater budgetary participation contributes to managerial performance and attitudes in high-environmental-uncertainty situations but hampers performance and attitudes in low-uncertainty situations. Higher budgetary participation reduces managers' propensity to create slack in high- (but not in low-) uncertainty conditions.
Patent•
18 Feb 1986TL;DR: In this article, a reference display system that receives information from an imaging system (e.g., a CT scanner or the like), that extracts or derives three-dimensional anatomical and/or pathological information about a part of a body (i.e., the brain or other organ) of a patient is introduced.
Abstract: A reference display system that receives information from an imaging system (e.g., a CT scanner or the like), that extracts or derives three-dimensional anatomical and/or pathological information about a part of a body (e.g., the brain or other organ) of a patient. The information is digitized in the imaging system and is introduced to a computer that is programmed to reformat the digitized information to provide as output electric signal representative of the digitized information. An optical display system (e.g., a cathode ray tube, CRT, and related circuitry) is connected to receive the output of the computer and is operable to present the reformatted information at a determined plane during an operative procedure. An operating microscope is freely located in the operative location relative to the patient during the operative procedure, the focal plane of the microscope establishing the determined plane. A way is provided to establish the spatial relationship among the imaging system, the patient, and the focal plane of the microscope; and a mechanism is provided to project the reformatted imaging system information into the optics and onto the focal plane of the operating microscope during the operative procedure, the reformatted image being displayed as an overlay upon the optical image of the body part on which the operation is being performed.
01 Aug 1986
TL;DR: Given a source, a destination, and a set of polygonal obstacles of size n, an size data structure can be used to find a reasonable approximation to the shortest path between the source and the destination in &Ogr;(n log n) time.
Abstract: Given a set S of points in the plane, there is a triangulation of S such that a path found within this triangulation has length bounded by a constant times the straight-line distance between the endpoints of the path. Specifically, for any two points a and b of S there is a path along edges of the triangulation with length less than √10 times |ab|, where |ab| is the straight-line Euclidean distance between a and b. Thus, a shortest path in this planar graph is less than about 3 times longer than the corresponding straight-line distance. The triangulation that has this property is the L1 metric Delaunay triangulation for the set 5. This result can be applied to motion planning in the plane. Given a source, a destination, and a set of polygonal obstacles of size n, an O(n) size data structure can be used to find a reasonable approximation to the shortest path between the source and the destination in O(n log n) time.
TL;DR: Smoking may actually be a protective exposure, especially animal data indicating a dopaminergic effect of smoking on the brain, and other lines of evidence support this view.
Abstract: Epidemiologic evidence has suggested a negative association between cigarette smoking and the risk of Parkinson's disease. Although many of the studies had limitations, in aggregate they suggest that smoking may actually be a protective exposure. Other lines of evidence support this view, especially animal data indicating a dopaminergic effect of smoking on the brain.
TL;DR: It was found that activation of the T-cell antigen receptor rendered the cells responsive to interleukin-2, but did not move them through the cell cycle, instead, IL-2 stimulated G1 progression to S phase, or lymphocyte "blastic transformation."
Abstract: In studies to determine the biochemical mechanisms responsible for cell proliferation, synchronized T cells were used as a model for cellular growth control. By metabolic and morphologic criteria, it was found that activation of the T-cell antigen receptor rendered the cells responsive to interleukin-2 (IL-2), but did not move them through the cell cycle. Instead, IL-2 stimulated G1 progression to S phase, or lymphocyte "blastic transformation." During IL-2-promoted G1 progression, expression of the cellular proto-oncogene c-myb was induced transiently at six to seven times basal levels, maximal levels occurring at the midpoint of G1.
TL;DR: A role for endogenous analgesia is incorporated into a more general model of aversively motivated behavior that is called the perceptual-defensive-recuperative m ~ d e l .
Abstract: Endogenous analgesic systems may play a critical role in modulating the behavioral responses that evolved as antipredator defense. Animals can innately recognize certain environmental danger signals and can learn to recognize others. To such danger stimuli they react with complex and coordinated innate defensive behavioral patterns.’ Bolles and I have pointed out that nociceptive stimulation delivered by the predator to the prey may disrupt these defensive behavioral patterns? For example, limping on an injured leg would compromise flight; the movements involved in licking a wound could attract a predator’s attention. If endogenous analgesic mechanisms were activated by the same stimuli that activate defensive behaviors, analgesia could function to prevent these disruptive influences of nociception on coordinated defensive activities. We incorporated such a role for endogenous analgesia into a more general model of aversively motivated behavior that we call the perceptual-defensive-recuperative m ~ d e l . ~ . ~
TL;DR: It is indicated that a large proportion of schizophrenic patients experienced major depressive episodes, and that these can be reliably identified and the relationship between depression and suicide disappears when hopelessness is taken into account.
Abstract: Hospital records for 104 schizophrenic patients, 15 of whom subsequently committed suicide, were rated blindly for individual depressive symptoms comprising DSM III major depressive episode, and for hopelessness. Our results indicate that a large proportion of schizophrenic patients experienced major depressive episodes, and that these can be reliably identified. Presuicidal schizophrenics also experienced depressed mood, but only a minority developed the full syndrome; they typically exhibited the psychological, but not somatic symptoms. The relationship between depression and suicide disappears when hopelessness is taken into account.
TL;DR: In this paper, the authors introduce the concept of a negotiated belief structure to help analyze how political and information-processing forces work to create decision premises within a strategy-making group, defined as the beliefs or assumptions that underscore a strategic decision.
TL;DR: In this article, it was shown that the addition of 750 ppm by weight (0.35 at%) of boron to stoichiometric Ni3Al reduces the effectiveness with which grain boundaries strengthen the alloy.
TL;DR: The results indicate that when the source of nervousness is due to changes in decisions caused by a rolling planning horizon, safety stock and lot-for-lot approaches are not cost effective.
Abstract: This research examines the effectiveness of alternative strategies for dealing with the problem of order instability, or nervousness, which occurs in Material Requirements Planning systems. Nervousness can be particularly disruptive in multi-level production processes where a change in order size or timing at one level can result in changes at other levels.
This study proposes and evaluates five different strategies for treating nervousness caused by the interaction of lot-sizing decisions and the planning horizon. Not evaluated here are the effects on order instability caused by demand uncertainty or supply and lead-time uncertainty. The five strategies examined are: 1 Freezing the schedule within the planning horizon, 2 Lot-for-Lot after stage 1, 3 Safety stocks, 4 Forecast beyond the planning horizon, and 5 Change cost procedure.
A series of simulation experiments was conducted to test the effectiveness of the five strategies on schedule stability and system costs. The experiments were constructed to evaluate the impacts of various lot-sizing methods, the length of the planning horizon, setup and holding cost parameters and product assembly structure.
The results indicate that when the source of nervousness is due to changes in decisions caused by a rolling planning horizon, safety stock and lot-for-lot approaches are not cost effective. Under most conditions, the strategies of incorporating a change cost to discourage schedule changes or freezing the schedule within the planning horizon appear to be dominant.
Abstract: Competing processes previously called ‘‘selective decay’’ and ‘‘dynamic alignment’’ are studied numerically for two‐dimensional magnetohydrodynamic turbulence. In selective decay, the energy decays relatively to mean‐square vector potential, and in dynamic alignment, the energy decays relatively to cross helicity. In the former case, the kinetic (fluid) energy decays to zero and the magnetic energy occupies the largest scales allowed by the boundary conditions. In the latter case, the velocity field and magnetic field become aligned and energetically equipartitioned. An extensive study of the initial value problem, with viscous and resistive dissipation, indicates that four distinct regimes of behavior are possible: a magnetically dominated regime, a velocity dominated regime, a dynamic alignment dominated regime, and a transition regime separating the others in parameter space. An analytical variational problem predicts several features seen in the computations, including geometrical alignment of velocity and magnetic fields, constraints on global quantities in the long‐time limit, and in some cases, condensation to long wavelength modes.
Patent•
19 Aug 1986TL;DR: In this paper, a method of distillation employing a heat pump (which may be driven by a compressor) using a vapor stream from within the distillation system as a heat source and a liquid stream from the same source as heat sink is described.
Abstract: A method of distillation employing a heat pump (which may be driven by a compressor) using a vapor stream from within the distillation system as a heat source and a liquid stream from within the distillation system as a heat sink. The selection of heat-source vapors and heat-sink liquid is such that at least one is withdrawn from the phase-contracting region of the distillation system. The return of streams withdrawn from the phase-contacting region of the distillation system to the distillation system is such that at least one of the streams is returned at a temperature different from that of the point from which it was withdrawn, and all withdrawn streams are returned in manner such that a stream removed as vapor is returned at a point with a temperature at most that at the point it was withdrawn, and a stream removed as liquid is returned at a point with a temperature at least that at which it was withdrawn. Embodiments of the basic method where vapor only, liquid only, or both liquid and vapor are withdrawn from and returned to the phase-contacting region of the distillation system are considered. The impact of the invention is to reduce the heat requirement of distillation in exchange for an amount of work which is usually small because the temperature difference between heat sources and sinks is minimized. Combination of the basic distillation method with multi-effect distillation, convention overhead-to-reboiler heat pumped distillation, azeotropic and extractive distillation, and fermentative production of volatile compounds is described. A system specifically designed for the separation of ethanol-water mixtures which utilizes the present invention and extractive distillation in a system with extensive heat integration is presented.
Journal Article•
TL;DR: Induction by EQ of enzymes important to AFB1 detoxication, such as GST, can lead to enhanced carcinogen elimination, as well as reductions of AFB1-DNA adduct formation and subsequent expression of preneoplastic lesions, and, ultimately, neoplasia.
Abstract: The effects of dietary administration of ethoxyquin (EQ) on aflatoxin B1 (AFB1) metabolism, DNA adduct formation and removal, and hepatic tumorigenesis were examined in male Fischer rats. Rats were fed a semipurified diet containing 0.4% EQ for 1 wk, gavaged with 250 µg of AFB1 per kg 5 times a wk during the next 2 wk, and, finally, restored to the control diet 1 wk after cessation of dosing. At 4 mo, focal areas of hepatocellular alteration were identified and quantitated by staining sections of liver for γ-glutamyl transpeptidase. Treatment with EQ reduced by >95% both area and volume of liver occupied by γ-glutamyl transpeptidase-positive foci. Utilizing the same multiple dosing protocol, patterns of covalent modifications of DNA by AFB1 were determined. EQ produced a dramatic reduction in the binding of AFB1 to hepatic DNA: 18-fold initially and 3-fold at the end of the dosing period. Although binding was detectable at 3 and 4 mo postdosing, no effect of EQ was observed, suggesting that these persistent adducts are not of primary relevance to AFB1 carcinogenesis. Analysis of nucleic acid bases by high-performance liquid chromatography revealed no qualitative differences in adduct species between treatment groups. The inhibitory effect of EQ on AFB1 binding to DNA and tumorigenesis appears related to induction of detoxication enzymes. Rats fed 0.4% EQ for 7 days showed a 5-fold increase in hepatic cytosolic glutathione S-transferase (GST)-specific activities. Multiple molecular forms of GST were induced, and concomitant elevations in messenger RNA levels coding for the synthesis of GST subunits were observed. Correspondingly, biliary elimination of AFB1-glutathione conjugate was increased 4.5-fold in animals on the EQ diet during the first 2 h following p.o. administration of 250 µg of AFB1 per kg. Thus, induction by EQ of enzymes important to AFB1 detoxication, such as GST, can lead to enhanced carcinogen elimination, as well as reductions of AFB1-DNA adduct formation and subsequent expression of preneoplastic lesions, and, ultimately, neoplasia.
TL;DR: An interdisciplinary analysis of ostracism as a common area of behavior, combining biology, law, and the social sciences can produce insights that none of these fields alone can provide, and should increase the understanding of human nature and the functions of law.
TL;DR: Minor metabolites produced from tryptophan in response to IFN-gamma and excreted into the medium are not parasitostatic, however, it is unlikely that either metabolite reaches intracellular concentrations that are sufficient to suppress the growth of the parasite.