Showing papers by "Columbia University published in 1990"
TL;DR: An integrated molecular modeling system for designing and studying organic and bioorganic molecules and their molecular complexes using molecular mechanics is described in this article, which allows the construction, display and manipulation of molecules and complexes having as many as 10,000 atoms and provides interactive, state-of-the-art molecular mechanics on any subset of up to 1000 atoms.
Abstract: An integrated molecular modeling system for designing and studying organic and bioorganic molecules and their molecular complexes using molecular mechanics is described. The graphically controlled, atom-based system allows the construction, display and manipulation of molecules and complexes having as many as 10,000 atoms and provides interactive, state-of-the-art molecular mechanics on any subset of up to 1,000 atoms. The system semiautomates the graphical construction and analysis of complex structures ranging from polycyclic organic molecules to biopolymers to mixed molecular complexes. We have placed emphasis on providing effective searches of conformational space by a number of different methods and on highly optimized molecular mechanics energy calculations using widely used force fields which are supplied as external files. Little experience is required to operate the system effectively and even novices can use it to carry out sophisticated modeling operations. The software has been designed to run on Digital Equipment Corporation VAX computers interfaced to a variety of graphics devices ranging from inexpensive monochrome terminals to the sophisticated graphics displays of the Evans & Sutherland PS300 series.
3,507 citations
TL;DR: This paper found that the three-day price reactions to announcements of earnings for quarters t + 1 through I + 4 are predictable, based on earnings of quarter r. Even more surprisingly, the signs and magnitudes of the three day reactions are related to the autocorrelation structure of earnings, as if stock prices fail to reflect the extent to which each firm's earnings series differs from a seasonal random walk.
2,039 citations
TL;DR: The observed differences between the partial pressure of CO2 in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO2, and a large amount of the CO2 is apparently absorbed on the continents by terrestrial ecosystems.
Abstract: Observed atmospheric concentrations of CO2 and data on the partial pressures of CO2 in surface ocean waters are combined to identify globally significant sources and sinks of CO2. The atmospheric data are compared with boundary layer concentrations calculated with the transport fields generated by a general circulation model (GCM) for specified source-sink distributions. In the model the observed north-south atmospheric concentration gradient can be maintained only if sinks for CO2 are greater in the Northern than in the Southern Hemisphere. The observed differences between the partial pressure of CO2 in the surface waters of the Northern Hemisphere and the atmosphere are too small for the oceans to be the major sink of fossil fuel CO2. Therefore, a large amount of the CO2 is apparently absorbed on the continents by terrestrial ecosystems.
2,016 citations
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TL;DR: In this article, the authors consider how prior outcomes are combined with the potential payoffs offered by current choices, and propose an editing rule to describe how decision makers frame such problems. And they also present data from real money experiments supporting a "house money effect" (increased risk seeking in the presence of a prior gain) and "break-even effects" (that outcomes which offer a chance to break even are especially attractive).
Abstract: How is risk-taking affected by prior gains and losses? While normative theory implores decision makers to only consider incremental outcomes, real decision makers are influenced by prior outcomes. We first consider how prior outcomes are combined with the potential payoffs offered by current choices. We propose an editing rule to describe how decision makers frame such problems. We also present data from real money experiments supporting a "house money effect" (increased risk seeking in the presence of a prior gain) and "break-even effects" (in the presence of prior losses, outcomes which offer a chance to break even are especially attractive).
1,973 citations
TL;DR: Germ-line transmission of the inactivated IGF-II gene from male chimaeras yielded heterozygous progeny that were smaller than their ES cell-derived wild-type littermates (about 60% of normal body weight) and these growth-deficient animals were otherwise apparently normal and fertile.
Abstract: Growth factors are thought to function as pivotal autocrine-paracrine regulatory signals during embryonic development. Insulin-like growth factor II (IGF-II), a mitogenic polypeptide for a variety of cell lines, could have such a role, as indicated by the pattern of expression of its gene during rodent development. The IGF-II gene uses at least three promoters and expresses several transcripts in many tissues during the embryonic and neonatal periods, whereas expression in adult animals is confined to the choroid plexus and the leptomeninges. To examine the developmental role of IGF-II, we have begun to study the consequences of introducing mutations at the IGF-II gene locus in the mouse germ line. We have disrupted one of the IGF-II alleles in cultured mouse embryonic stem (ES) cells by gene targeting and constructed chimaeric animals. Germ-line transmission of the inactivated IGF-II gene from male chimaeras yielded heterozygous progeny that were smaller than their ES cell-derived wild-type littermates (about 60% of normal body weight). These growth-deficient animals were otherwise apparently normal and fertile. The effect of the mutation was exerted during the embryonic period. These results provide the first direct evidence for a physiological role of IGF-II in embryonic growth.
1,660 citations
01 Jan 1990
1,512 citations
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01 Jan 1990TL;DR: A schema-focused approach to group psychotherapy for outpatients is presented in this article, where Schema therapy draws on the cognitive-behavioral, attachment, psychodynamic, and emotion-focused.
Abstract: Patients with borderline personality disorder (BPD) often receive mental health treatment. trial of schema-focused therapy vs transference-focused psychotherapy. the borderline personality disorder study of cognitive therapy (BOSCOT) trial. A schema-focused approach to group psychotherapy for outpatients. ABSTRACT This article presents the Schema Therapy (Young, Klosko, & Weishaar, 2003) approach to the treatment of borderline personality disorder. Schema therapy draws on the cognitive-behavioral, attachment, psychodynamic, and emotion-focused Article: Schema Therapy for Borderline Personality Disorder. Jeffery Young (1990) developed Schema Therapy to treat personality disordered Cognitive Therapy for Personality Disorders: A Schema Focused Approach.
1,496 citations
TL;DR: Uranium-thorium ages obtained by mass spectrometry from corals raised off the island of Barbados confirm the high precision of this technique over at least the past 30,000 years as discussed by the authors.
Abstract: Uranium-thorium ages obtained by mass spectrometry from corals raised off the island of Barbados confirm the high precision of this technique over at least the past 30,000 years. Comparison of the U-Th ages with C-14 ages obtained on the Holocene samples shows that the U-Th ages are accurate, because they accord with the dendrochronological calibration. Before 9,000 yr BP, the C-14 ages are systematically younger than the U-Th ages, with a maximum difference of about 3500 yr at about 20,000 yr BP. The U-Th technique thus provides a way of calibrating the radiocarbon timescale beyond the range of dendrochronological calibration.
1,328 citations
01 Jan 1990
TL;DR: This presentation discusses the construction of the Poisson-Boltzmann Equation, and some of the methods used to achieve this result.
Abstract: CONTENTS PERSPECTIVE AND OVERVIEW 301 DIELECTRIC THEORY . . . . . . . . . . . ... . . . . . ........ . . . . . . . 303 The Poisson Equation . . . . . . . . . . . . . . . . . ... . . . . . . ... . . . ... . 303 Electronic Polarizability 304 Permanent Dipoles . . . ..... . . . ...... . . . . . . .... . . . . ... . ... ..... 307 Mobile Ions . . . . . . . . . . . . . . . . . ... . . . . . ... ... . . . . . ... . . . . . . . . . . . . . . . . . . . . . ... . . . . ... . ....... 309 METHODS 3 1 0 The Protein Dipole Langevin Dipole Method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 1 2 Analytical Solutions t o the Poisson-Boltzmann Equation 3 1 2 Numerical Solutions to the Poisson-Boltzmann Equation 3 13 The Finite Diff erence Poisson-Boltzmann Method ......... . . . . . . . ..... . . . . . . ... . . ... 3 14 APPLICATIONS ..... 317 Electrical Potentials around Macromolecules. . . . . . . . . . . . . . . . . . . . .. ..... . . . . .. . ... . .. . . . . . . . . ..... . ...... 317 Solvation Energies . . ....... . . . . . . . . . . . . . . . . . . . . . . . . . 319 Catalysis ... ... . . . ... . . ... . ... . . . ....... . . . . . . . . . . . . .... ... ....... ..... . . ... . . . . . . 321 Acid-Base Equilibria. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 322 Redox Potentials . . ... . . . . .... . . . . . . ..... . . . . ... . . ........ ...... 324 Forces in DynamiCS Simulations . . . . . . . .... . . . . . . . . . . . . . . . . . ... ..... . . . . . . . . . . . . . . . . . . . . . ..... ... 326 Electrostatic Energies and Stability: Folding, Denaturation, and Binding . ........ . . . ..... 327 SUMMARY AND PROSPECTS ....... ......... . . . . . ....... . . . . . . . . . . . . . . . . . . . . 329
1,272 citations
TL;DR: A meta-analysis of results from 320 published studies relates environmental, strategic and organizational factors to financial performance as discussed by the authors, finding that concentration and growth have a relatively consistent positive impact on performance.
Abstract: A meta-analysis of results from 320 published studies relates environmental, strategic and organizational factors to financial performance. Some factors e.g., concentration and growth have been studied widely and have a relatively consistent positive impact on performance. Other widely-studied factors e.g., size have few consistent effects. Many factors particularly organizational variables are understudied. We suggest implications for research and management practice.
1,190 citations
Posted Content•
TL;DR: In this article, the authors argue that the incentive for investment and growth is too high if taxes are lump sum, and that tax policies that encourage investment can raise the growth rate and levels of utility.
Abstract: The recent literature on endogenous economic growth allows for effects of fiscal policy on long-term growth. If the social rate of return on investment exceeds the private return, then tax policies that encourage investment can raise the growth rate and levels of utility. An excess of the social return over the private return can reflect learning-by-doing with spillover effects, the financing of government consumption purchases with an income tax, and monopoly pricing of new types of capital goods. Tax incentives for investment are not called for if the private rate of return on investment equals the social return. This situation applies in growth models if the accumulation of a broad concept of capital does not entail diminishing returns, or if technological progress appears as an expanding variety of consumer products. In growth models that incorporate public services, the optimal tax policy hinges on the characteristics of the services. If the public services are publicly-provided private goods, which are rival and excludable, or publiclyprovided public goods, which are non-rival and non-excludable, then lump-sum taxation is superior to income taxation. Many types of public goods are subject to congestion, and are therefore rival but to some extent nonexcludable. In these cases, income taxation works approximately as a user fee and can therefore be superior to lump-sum taxation. In particular, the incentives for investment and growth are too high if taxes are lump sum. We argue that the congestion model applies to a wide array of public expenditures, including transportation facilities, public utilities, courts, and possibly national defense and police.
TL;DR: In this article, the authors compared variations of the self-imposed delay-of-gratification situation in preschool to determine when individual differences in this situation may predict aspects of cognitive and self-regulatory competence and coping in adolescence.
Abstract: Variations of the self-imposed delay-of-gratification situation in preschool were compared to determine when individual differences in this situation may predict aspects of cognitive and self-regulatory competence and coping in adolescence.
TL;DR: The Chern-Simons Lagrangian would rotate the plane of polarization of radiation from distant galaxies, an effect which is not observed, and the magnitude of the vector is 1.7 times the Hubble constant.
Abstract: The Chern-Simons Lagrangian has been studied previously in (2+1)-dimensional spacetime, where it is both gauge and Lorentz invariant. In 3+1 dimensions, this term couples the dual electromagnetic tensor to an external four-vector. If we take this four-vector to be fixed, the term is gauge invariant but not Lorentz invariant. In this paper, we examine both the theoretical consequences of such a modification and observational limits we can put on its magnitude. The Chern-Simons term would rotate the plane of polarization of radiation from distant galaxies, an effect which is not observed. From the observations we deduce that the magnitude of the vector is 1.7\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}42}$${h}_{0}$ GeV, where ${h}_{0}$ is the Hubble constant in units of 100 km ${\mathrm{sec}}^{\mathrm{\ensuremath{-}}1}$ ${\mathrm{Mpc}}^{\mathrm{\ensuremath{-}}1}$.
TL;DR: In this paper, a logistic regression model for characterizing differential item functioning (DIF) between two groups is presented and a distinction is drawn between uniform and non-uniform DIF in terms of the parameters of the model.
Abstract: A logistic regression model for characterizing differential item functioning (DIF) between two groups is presented. A distinction is drawn between uniform and nonuniform DIF in terms of the parameters of the model. A statistic for testing the hypothesis of no DIF is developed. Through simulation studies, it is shown that the logistic regression procedure is more powerful than the Mantel-Haenszel procedure for detecting nonuniform DIF and as powerful in detecting uniform DIF.
TL;DR: Moral exclusion occurs when individuals or groups are perceived as outside the boundary in which moral values, rules, and considerations of fairness apply as discussed by the authors, and therefore, harming or exploiting them appears to be appropriate, acceptable, or just.
Abstract: Moral exclusion occurs when individuals or groups are perceived as outside the boundary in which moral values, rules, and considerations of fairness apply. Those who are morally excluded are perceived as nonentities, expendable, or undeserving. Consequently, harming or exploiting them appears to be appropriate, acceptable, or just. This broad definition encompasses both severe and mild forms of moral exclusion, from genocide to discrimination. The paper discusses the antecedents and symptoms of moral exclusion, and the interaction between the psychological and social factors that foster its development. Empirical research on moral exclusion is needed to pinpoint its causes, to predict its progression, and to effect change in social issues that involve the removal of victims from our moral communities. The last section of the paper introduces the articles that follow.
TL;DR: The murine oct-3 gene encodes a transcription factor containing a POU-specific domain and a homeodomain, which is expressed in the totipotent and pluripotent stem cells of the pre-gastrulation embryo and is down-regulated during differentiation to endoderm and mesoderm, suggesting that it has a role in early development.
Abstract: The murine oct-3 gene encodes a transcription factor containing a POU-specific domain and a homeodomain. In marked contrast to other homeodomain-encoding genes,oct-3 is expressed in the totipotent and pluripotent stem cells of the pre-gastrulation embryo and is down-regulated during differentiation to endoderm and mesoderm, suggesting that it has a role in early development. The oct-3 gene is also expressed in primordial germ cells and in the female germ line.
Book•
01 Jul 1990TL;DR: Note: V. Madisetti, D. B. Williams, Eds.
TL;DR: The results that the authors observed in heterozygotes suggest that CETP normally plays a part in the regulation of levels of HDL subclass 2, and the lipoprotein profile of persons with CETP deficiency is potentially antiatherogenic and may be associated with an increased life span.
Abstract: Background and Methods. The plasma cholesteryl-ester transfer protein (CETP) catalyzes the transfer of cholesteryl esters from high-density lipoprotein (HDL) to other lipoproteins. We recently described a Japanese family with increased HDL levels and CETP deficiency due to a splicing defect of the CETP gene. To assess the frequency and phenotype of this condition, we screened 11 additional families with high HDL levels by means of a radioimmunoassay for CETP and DNA analysis. Results. We found the same CETP gene mutation in four families from three different regions of Japan. Analysis of Restriction-Fragment Length polymorphisms of the mutant CETP allele showed that all probands were homozygous for the identical haplotype. Family members homozygous for CETP deficiency (n = 10) had moderate hypercholesterolemia (mean total cholesterol level [±SD], 7.01±0.83 mmol per liter), markedly increased levels of HDL cholesterol (4.24±1.01 mmol per liter) and apolipoprotein A-I, and decreased levels of low-d...
TL;DR: Results indicate that VPF can modulate the coagulant properties of endothelium and monocytes, and can promote monocyte migration into the tumor bed, which suggests one mechanism through which tumor-derived mediators can alter properties of the vessel wall.
Abstract: Systemic infusion of low concentrations of tumor necrosis factor/cachectin (TNF) into mice that bear TNF-sensitive tumors leads to activation of coagulation, fibrin formation, and occlusive thrombosis exclusively within the tumor vascular bed. To identify mechanisms underlying the localization of this vascular procoagulant response, a tumor-derived polypeptide has been purified to homogeneity from supernatants of murine methylcholanthrene A-induced fibrosarcomas that induces endothelial tissue factor synthesis and expression (half-maximal response at approximately 300 pM), and augments the procoagulant response to TNF in a synergistic fashion. This tumor-derived polypeptide was identified as the murine homologue of vascular permeability factor (VPF) based on similar mobility on SDS-PAGE, an homologous NH2-terminal amino acid sequence, and recognition by a monospecific antibody to guinea pig VPF. In addition, VPF was shown to induce monocyte activation, as evidenced by expression of tissue factor. Finally, VPF was shown to induce monocyte chemotaxis across collagen membranes and endothelial cell monolayers. Taken together, these results indicate that VPF can modulate the coagulant properties of endothelium and monocytes, and can promote monocyte migration into the tumor bed. This suggests one mechanism through which tumor-derived mediators can alter properties of the vessel wall.
TL;DR: In this article, the authors present results bearing on the sea level record for the past 130,000 years; they conclude that the last deglaciation started 3, 000 years earlier than previously thought and confirm that there were two surges in melt water at about 11 kyr and 14 kyr BP (before present).
Abstract: THE study of the sea level record during the last glacial cycle has primarily proceeded indirectly by means of oxygen isotope measurements on foraminifera from deep-sea sediments1,2. The direct approach of dating sea level indicators stagnated during the past decade, mainly because the samples required to complete our knowledge of the past glaciations are below the present-day sea level3–7. Using the 14C ages of Acropora palmata samples collected by drilling offshore the island of Barbados, Fairbanks8 presented the first detailed chronology for the last deglaciation. This radiocarbon chronology is limited to the past 30 kyr because of the short half-life of 14C (5,730 yr); we must therefore rely on other dating methods to obtain information for the whole last glacial cycle. During the past four years 230Th–234U dating of corals by thermal-ionization mass spectrometry has been shown to be significantly more precise and accurate than the classical α counting method9–14. We have used this technique to measure U–Th ages in coral samples from the Barbados collection and from subaerially exposed outcrops (see also ref. 15). Here we present results bearing on the sea level record for the past 130,000 years; we conclude that the last deglaciation started 3,000 years earlier than previously thought and confirm that there were two surges in melt water8 at about 11 kyr and 14 kyr BP (before present).
TL;DR: The authors analyzes incentives for voluntary disclosure of proprietory information in a static entry game and shows that a fully revealing disclosure equilibrium exists when the prior of the market is optimistic or the entry cost is relatively low.
01 Jan 1990
TL;DR: In this paper, a technique for the determination of organic carbon and nitrogen in small samples (5 mg) of marine sediments that optimizes the analytical capabilities of the Carlo Erba NA-1500 Elemental Analyzer is described.
Abstract: A technique is described for the determination of organic carbon and nitrogen in small samples (5 mg) of marine sediments that optimizes the analytical capabilities of the Carlo Erba NA-1500 Elemental Analyzer. This instrument analyses total carbon, nitrogen and sulfur in solid samples by flash combustion. Organic and inorganic forms of carbon are differentiated by sample manipulation prior to analysis without loss of nitrogen. Organic carbon is determined after removing carbonate carbon by acidification with sulfurous acid in situ within aluminum sample cups, thus eliminating loss of acid-soluble organic carbon during carbonate dissolution, or the necessity of determining organic carbon by “difference-on-combustion”. Excess acid is volatized as SO2 and H2O upon drying, eliminating the dual problems of retention of waters-of-hydration of calcium salts and “excess” acid. The procedure provides rapid and rouitine analyses of marine sediments, yielding a relative precision of ±0.3% of the measured value for organic carbon and ±1.6% for nitrogen, and blank levels 0.31 ± 0.085 μg-carbon and 0 μg-nitrogen. Conservatively estimated absolute and relative detection limits are 0.62 μg-carbon (2 times mean blank value) and 0.01% carbon, respectively.
Veterans Health Administration1, University of Miami2, University of Florida3, Brown University4, University of California, Los Angeles5, Mount Sinai St. Luke's and Mount Sinai Roosevelt6, Harvard University7, University of Pennsylvania8, University of Louisville9, Cornell University10, University of Arizona11, Columbia University12, Abbott Laboratories13, Merck & Co.14
TL;DR: Hepatitis B e antigen and hepatitis B viral DNA disappeared from serum significantly more often in the patients given prednisone plus interferon or 5 million units of interferons alone than in the untreated controls.
Abstract: Background and Methods. Chronic hepatitis B is a common and often progressive liver disorder for which there is no accepted therapy. To assess the efficacy of treatment with interferon, we randomly assigned patients with chronic hepatitis B to one of the following regimens: prednisone for 6 weeks followed by 5 million units of recombinant interferon alfa-2b daily for 16 weeks; placebo followed by 5 million units of interferon daily for 16 weeks; placebo followed by 1 million units of interferon daily for 16 weeks; or observation with no treatment. Results. Hepatitis B e antigen and hepatitis B viral DNA disappeared from serum significantly more often in the patients given prednisone plus interferon (16 of 44 patients, or 36 percent) or 5 million units of interferon alone (15 of 41; 37 percent) than in the untreated controls (3 of 43; 7 percent; P<0.001); the difference between those given 1 million units of interferon (7 of 41; 17 percent) and the controls was not significant. The strongest indep...
TL;DR: Appendicular skeletal muscle mass estimated by DPA is thus a potentially practical and accurate method of quantifying human skeletal Muscle mass in vivo.
TL;DR: A survey on the economics of product variety can be found in this article, where the authors analyse the effect of this balance in different situations, and compare the degree of product diversity for different market structures with each other and with the optimum.
Abstract: Demand for variety may arise from a taste for diversity in individual consumption and/or from diversity in tastes even when each consumer chooses a single variant. The full degree of variety potentially demanded will not, in general, be supplied because scale economies even to a small degree mean that the potential welfare or revenue gain from greater variety must be balanced against the lower unit production costs with fewer variants. The economics of product variety consists essentially in analysing the effect of this balance in different situations, and comparing the degree of product variety for different market structures with each other and with the optimum. The survey commences with the work on market structures with single product firms generalized monopolistic competition, tracing modern developments in both the Chamberlinian and Hotelling traditions. The latter has been particularly fruitful, due to the expansion of the original locational ideas into virtual spaces in product characteristics. The emphasis in recent work on product variety has been on multiproduct firms in both monopolistic and oligopolistic structures, including strategic market preemption. Although most work has been in a full information context, there have been advances in product variety under imperfect information either by consumers to properties of the firms' products or firms as to consumers' demands.
TL;DR: The ability to alter the endocrine response with techniques such as epidural anesthesia, the able to specifically block certain aspects of the response, and the ability to synthesize potential beneficial mediators with recombinant DNA techniques may allow for modulating the response to decrease debility and complications.
Abstract: Recent investigation has demonstrated that the response to stress is mediated by complex interactions between the nervous, endocrine, immune, and hematopoietic systems. Not only is the neuroendocrine system operative but monokines and lymphokines, such as IL-1, IL-6, and TNF, also play important roles. The discovery of these mediators, along with that of macrophage-derived substances that operate at the local wound level, such as platelet-derived, basic fibroblast, transforming, and epidermal growth factors, coupled with advances in molecular biology portends much for the future. The ability to alter the endocrine response with techniques such as epidural anesthesia, the ability to specifically block certain aspects of the response (e.g., with adrenergic and prostaglandin antagonists), and the ability to synthesize potential beneficial mediators with recombinant DNA techniques (e.g., GH) may allow for modulating the response to decrease debility and complications.
TL;DR: A meta-analysis of 213 applications of diffusion models from 15 articles relates model parameters to the nature of the innovation, the country under study, model specification, and estimation procedure.
Abstract: A meta-analysis of 213 applications of diffusion models from 15 articles relates model parameters to the nature of the innovation, the country under study, model specification, and estimation proce...
TL;DR: Observations indicate that the kainate/quisqualate receptors are encoded by a family of genes and are likely to be composed of hetero-oligomers of at least two distinct subunits.