scispace - formally typeset
Search or ask a question

Showing papers by "Columbia University published in 1996"


Journal ArticleDOI
Claude Amsler1, Michael Doser2, Mario Antonelli, D. M. Asner3  +173 moreInstitutions (86)
TL;DR: This biennial Review summarizes much of particle physics, using data from previous editions.

12,798 citations


Journal ArticleDOI
TL;DR: Carvedilol reduces the risk or death as well as the risk of hospitalization for cardiovascular causes in patients with heart failure who are receiving treatment with digoxin, diuretics, and an angiotensin-converting-enzyme inhibitor.
Abstract: Background Controlled clinical trials have shown that beta-blockers can produce hemodynamic and symptomatic improvement in chronic heart failure, but the effect of these drugs on survival has not been determined. Methods We enrolled 1094 patients with chronic heart failure in a double-blind, placebo-controlled, stratified program, in which patients were assigned to one of four treatment protocols on the basis of their exercise capacity. Within each of the four protocols patients with mild, moderate, or severe heart failure with left ventricular ejection fractions ≤0.35 were randomly assigned to receive either placebo (n = 398) or the beta-blocker carvedilol (n = 696); background therapy with digoxin, diuretics, and an angiotensin-converting–enzyme inhibitor remained constant. Patients were observed for the occurrence of death or hospitalization for cardiovascular reasons during the following 6 months (12 months for the group with mild heart failure). Results The overall mortality rate was 7.8 percent in t...

3,899 citations


Journal ArticleDOI
TL;DR: A maximum-likelihood approach for automatically constructing maximum entropy models is presented and how to implement this approach efficiently is described, using as examples several problems in natural language processing.
Abstract: The concept of maximum entropy can be traced back along multiple threads to Biblical times. Only recently, however, have computers become powerful enough to permit the widescale application of this concept to real world problems in statistical estimation and pattern recognition. In this paper, we describe a method for statistical modeling based on maximum entropy. We present a maximum-likelihood approach for automatically constructing maximum entropy models and describe how to implement this approach efficiently, using as examples several problems in natural language processing.

3,392 citations


Journal ArticleDOI
TL;DR: As compared with conventional therapy, the continuous intravenous infusion of epoprostenol produced symptomatic and hemodynamic improvement, as well as improved survival in patients with severe primary pulmonary hypertension.
Abstract: Background Primary pulmonary hypertension is a progressive disease for which no treatment has been shown in a prospective, randomized trial to improve survival. Methods We conducted a 12-week prospective, randomized, multicenter open trial comparing the effects of the continuous intravenous infusion of epoprostenol (formerly called prostacyclin) plus conventional therapy with those of conventional therapy alone in 81 patients with severe primary pulmonary hypertension (New York Heart Association functional class III or IV). Results Exercise capacity was improved in the 41 patients treated with epoprostenol (median distance walked in six minutes, 362 m at 12 weeks vs. 315 m at base line), but it decreased in the 40 patients treated with conventional therapy alone (204 m at 12 weeks vs. 270 m at base line; P<0.002 for the comparison of the treatment groups). Indexes of the quality of life were improved only in the epoprostenol group (P<0.01). Hemodynamics improved at 12 weeks in the epoprostenol-treated pat...

2,495 citations


Journal ArticleDOI
TL;DR: In this paper, the authors identify a channel for an inverse relationship between income inequality and growth, and measure socio-political instability with indices which capture the occurrence of more or less violent phenomena of political unrest.

2,490 citations


Journal ArticleDOI
TL;DR: Some of the key developments leading to the current state of knowledge in p53 research are presented and how they either shed light on or add to the complexities of p53 are discussed.
Abstract: As the tale of p53 unfolds, it becomes ever more intriguing. Although our understanding of the critical and complex roles played by p53 is progressing rapidly, new findings continue to pose new paradoxes. Here we present some of these recent advances in p53 research and discuss how they either shed light on or add to the complexities of p53. Therefore, we only briefly summarize some of the key developments leading to our current state of knowledge. For further information, the reader is referred to several excellent reviews that have focused on p53 research (see Donehower and Bradley 1993; Levine 1993; Greenblatt et al. 1994; Oren 1994; Prives 1994; Kinzler and Vogelstein 1996).

2,445 citations


Journal ArticleDOI
24 Jul 1996-JAMA
TL;DR: There are striking similarities across countries in patterns of major depression and of bipolar disorder and the differences in rates for major depression across countries suggest that cultural differences or different risk factors affect the expression of the disorder.
Abstract: Objective. —To estimate the rates and patterns of major depression and bipolar disorder based on cross-national epidemiologic surveys. Design and Setting. —Population-based epidemiologic studies using similar methods from 10 countries: the United States, Canada, Puerto Rico, France, West Germany, Italy, Lebanon, Taiwan, Korea, and New Zealand. Participants. —Approximately 38 000 community subjects. Outcome Measures. —Rates, demographics, and age at onset of major depression and bipolar disorder. Symptom profiles, comorbidity, and marital status with major depression. Results. —The lifetime rates for major depression vary widely across countries, ranging from 1.5 cases per 100 adults in the sample in Taiwan to 19.0 cases per 100 adults in Beirut. The annual rates ranged from 0.8 cases per 100 adults in Taiwan to 5.8 cases per 100 adults in New Zealand. The mean age at onset shows less variation (range, 24.8-34.8 years). In every country, the rates of major depression were higher for women than men. By contrast, the lifetime rates of bipolar disorder are more consistent across countries (0.3/100 in Taiwan to 1.5/100 in New Zealand); the sex ratios are nearly equal; and the age at first onset is earlier (average, 6 years) than the onset of major depression. Insomnia and loss of energy occurred in most persons with major depression at each site. Persons with major depression were also at increased risk for comorbidity with substance abuse and anxiety disorders at all sites. Persons who were separated or divorced had significantly higher rates of major depression than married persons in most of the countries, and the risk was somewhat greater for divorced or separated men than women in most countries. Conclusions. —There are striking similarities across countries in patterns of major depression and of bipolar disorder. The differences in rates for major depression across countries suggest that cultural differences or different risk factors may affect the expression of the disorder.

2,245 citations



Journal ArticleDOI
TL;DR: It is demonstrated that FGF 1 is the only FGF that can activate all FGF receptor splice variants and the relative activity of all the other members of the FGF family is determined.

2,066 citations


Journal ArticleDOI
TL;DR: Gannon et al. as discussed by the authors explored the executive origins of firms' competitive moves by focusing on top management team characteristics, specifically on team heterogeneity, rather than on the more often studied environmental and organizational determinants of such behaviors.
Abstract: The authors acknowledge support from Columbia University's Management Institute. Warren Boeker, Sara Keck, John Michel, Peter Murmann, Michael Tushman, and Ruth Wageman made helpful suggestions on earlier drafts. We are grateful for access to the airline data base jointly assembled by the third author, Martin J. Gannon, Curtis M. Grimm, and Ken G. Smith. This paper explores the executive origins of firms' competitive moves by focusing on top management team characteristics, specifically on team heterogeneity, rather than on the more often studied environmental and organizational determinants of such behaviors. Arguing that competitive actions and responses represent different decision situations, we develop propositions about how heterogeneity may enhance some competitive behaviors but impair others. With a large sample of actions and responses of 32 U.S. airlines over eight years, we find results that largely conform to our propositions. The top management teams that were diverse, in terms of functional backgrounds, education, and company tenure, exhibited a relatively great propensity for action, and both their actions and responses were of substantial magnitude. Heterogeneous teams, by contrast, were slower in their actions and responses and less likely than homogeneous teams to respond to competitors' initiatives. Thus, although team heterogeneity is a double-edged sword, its overall net effect on airline performance, in terms of changes in market share and profits, was positive.*

1,916 citations


Journal ArticleDOI
22 Aug 1996-Nature
TL;DR: Evidence is presented that the 'receptor for advanced glycation end products' (RAGE) is such a receptor, and that it mediates effects of the peptide on neurons and microglia and indicates that it is relevant to the pathogenesis of neuronal dysfunction and death.
Abstract: Amyloid-beta peptide is central to the pathology of Alzheimer's disease, because it is neurotoxic--directly by inducing oxidant stress, and indirectly by activating microglia. A specific cell-surface acceptor site that could focus its effects on target cells has been postulated but not identified. Here we present evidence that the 'receptor for advanced glycation end products' (RAGE) is such a receptor, and that it mediates effects of the peptide on neurons and microglia. Increased expressing of RAGE in Alzheimer's disease brain indicates that it is relevant to the pathogenesis of neuronal dysfunction and death.

Journal ArticleDOI
31 Oct 1996-Nature
TL;DR: In this article, it was shown that light emission from single fluorescing nanocrystals of cadmium selenide under continuous excitation turns on and off intermittently with a characteristic timescale of about 0.5 seconds.
Abstract: SEMICONDUCTOR nanocrystals offer the opportunity to study the evolution of bulk materials properties as the size of a system increases from the molecular scale1,2. In addition, their strongly size-dependent optical properties render them attractive candidates as tunable light absorbers and emitters in optoelectronic devices such as light-emitting diodes3,4 and quantum-dot lasers5,6, and as optical probes of biological systems7. Here we show that light emission from single fluorescing nanocrystals of cadmium selenide under continuous excitation turns on and off intermittently with a characteristic timescale of about 0.5 seconds. This intermittency is not apparent from ensemble measurements on many nanocrystals. The dependence on excitation intensity and the change in on/off times when a passivating, high-bandgap shell of zinc sulphide encapsulates the nanocrystal8,9 suggests that the abrupt turning off of luminescence is caused by photo-ionization of the nanocrystal. Thus spectroscopic measurements on single nanocrystals can reveal hitherto unknown aspects of their photophysics.

BookDOI
01 Jan 1996
TL;DR: Basic principles - cell biology biochemistry bone re-modelling and mineral homeostasis the hormones of bone other systemic hormones that influence bone metabolism local regulators of bone molecular mechanisms of metabolic bone diseases pharmacological mechanisms of therapeutics methods in bone research.
Abstract: Basic principles - cell biology biochemistry bone re-modelling and mineral homeostasis the hormones of bone other systemic hormones that influence bone metabolism local regulators of bone molecular mechanisms of metabolic bone diseases pharmacological mechanisms of therapeutics methods in bone research.

Journal ArticleDOI
TL;DR: It is shown that this cognitive-affective processing disposition undermines intimate relationships and that rejection-sensitive people and their romantic partners are dissatisfied with their relationships.
Abstract: People who are sensitive to social rejection tend to anxiously expect, readily perceive, and overreact to it. This article shows that this cognitive-affective processing disposition undermines intimate relationships. Study 1 describes a measure that operationalizes the anxious-expectations component of rejection sensitivity. Study 2 provides experimental evidence that people who anxiously expect rejection readily perceive intentional rejection in the ambiguous behavior of others. Study 3 shows that people who enter romantic relationships with anxious expectations of rejection readily perceive intentional rejection in the insensitive behavior of their new partners. Study 4 demonstrates that rejection-sensitive people and their romantic partners are dissatisfied with their relationships. Rejection-sensitive men's jealousy and rejection-sensitive women's hostility and diminished supportiveness help explain their partners' dissatisfaction.

Journal ArticleDOI
TL;DR: This paper investigated the relationship between income distribution, democratic institutions, and growth and found that there is strong empirical support for two types of explanations, linking income distribution to sociopolitical instability and to the education/fertility decision.
Abstract: This paper investigates the relationship between income distribution, democratic institutions, and growth. It does so by addressing three main issues: the properties and reliability of the income distribution data, the robustness of the reduced form relationships between income distribution and growth estimated so far, and the specific channels through which income distribution affects growth. The main conclusion in this regard is that there is strong empirical support for two types of explanations, linking income distribution to sociopolitical instability and to the education/fertility decision. A third channel, based on the interplay of borrowing constraints and investment in human capital, also seems to receive some support by the data, although it is probably the hardest to test with the existing data. By contrast, there appears to be less empirical support for explanations based on the effects of income distribution on fiscal policy.

Journal ArticleDOI
TL;DR: Oestrogen use in postmenopausal women may delay the onset and decrease the risk of Alzheimer's disease and Prospective studies are needed to establish the dose and duration required to provide this benefit and to assess its safety in elderly post menopause women.

Journal ArticleDOI
TL;DR: The DISC-2 is a reliable and economical tool for assessing child psychopathology and the 2.3 version of the instrument provides a significant improvement over earlier versions.
Abstract: Objective To describe the NIMH Diagnostic Interview Schedule for Children (DISC) Version 2.3 and to provide data on its performance characteristics in the Methods for the Epidemiology of Child and Adolescent Mental Disorders (MECA) Study. Method Data were collected on the DISC-2.3 at four sites on 1,285 randomly selected children, aged 9 through 17 years, and their parents. Two hundred forty-seven of these child–parent pairs were reassessed on the DISC-2.3 by a clinician interviewer, 1 to 3 weeks later. Results Administration time was approximately 1 hour and the interview was acceptable to more than 90% of subjects. The reliability of questions to parents assessing impairment and age of onset was generally good to acceptable for most diagnoses but was less satisfactory for the child interview. Using information from parent and child, the prevalence for any diagnosis ranged from 50.6 If no impairment criteria were required to 5.4 if a Global Assessment Scale score of 50 or less was necessary. The prevalence of anxiety disorders and enuresis was markedly reduced by requiring attributable impairment. Conclusions The DISC-2 is a reliable and economical tool for assessing child psychopathology. Reliability of the DISC-P-2.3 is superior to that of the child DISC for most diagnoses but is least good for anxiety disorders. The 2.3 version of the instrument provides a significant improvement over earlier versions.

Journal ArticleDOI
TL;DR: In this article, the authors conducted a study of the major U.S. film studios from 1936 to 1965 and found that property-based resources in the movie industry were more valuable than other resources.
Abstract: This article continues to operationally define and test the resource-based view of the firm in a study of the major U.S. film studios from 1936 to 1965. We found that property-based resources in th...

Journal ArticleDOI
TL;DR: The results suggest that BMI is age and sex dependent when used as an indicator of body fatness, but that it is ethnicity independent in black and white adults.
Abstract: This study tested the hypothesis that body mass index (BMI) is representative of body fatness independent of age, sex, and ethnicity. Between 1986 and 1992, the authors studied a total of 202 black and 504 white men and women who resided in or near New York City, were ages 20-94 years, and had BMIs of 18-35 kg/m2. Total body fat, expressed as a percentage of body weight (BF%), was assessed using a four-compartment body composition model that does not rely on assumptions known to be age, sex, or ethnicity dependent. Statistically significant age dependencies were observed in the BF%-BMI relations in all four sex and ethnic groups (p values < 0.05-0.001) with older persons showing a higher BF% compared with younger persons with comparable BMIs. Statistically significant sex effects were also observed in BF%-BMI relations within each ethnic group (p values < 0.001) after controlling first for age. For an equivalent BMI, women have significantly greater amounts of total body fat than do men throughout the entire adult life span. Ethnicity did not significantly influence the BF%-BMI relation after controlling first for age and sex even though both black women and men had longer appendicular bone lengths relative to stature (p values < 0.001 and 0.02, respectively) compared with white women and men. Body mass index alone accounted for 25% of between-individual differences in body fat percentage for the 706 total subjects; adding age and sex as independent variables to the regression model increased the variance (r2) to 67%. These results suggest that BMI is age and sex dependent when used as an indicator of body fatness, but that it is ethnicity independent in black and white adults.

Journal ArticleDOI
TL;DR: Terminal repeat analysis of virus DNA from a KS lesion suggests a monoclonal expansion of KSHV in the KS tumor.
Abstract: The genome of the Kaposi sarcoma-associated herpesvirus (KSHV or HHV8) was mapped with cosmid and phage genomic libraries from the BC-1 cell line. Its nucleotide sequence was determined except for a 3-kb region at the right end of the genome that was refractory to cloning. The BC-1 KSHV genome consists of a 140.5-kb-long unique coding region flanked by multiple G + C-rich 801-bp terminal repeat sequences. A genomic duplication that apparently arose in the parental tumor is present in this cell culture-derived strain. At least 81 ORFs, including 66 with homology to herpesvirus saimiri ORFs, and 5 internal repeat regions are present in the long unique region. The virus encodes homologs to complement-binding proteins, three cytokines (two macrophage inflammatory proteins and interleukin 6), dihydrofolate reductase, bcl-2, interferon regulatory factors, interleukin 8 receptor, neural cell adhesion molecule-like adhesin, and a D-type cyclin, as well as viral structural and metabolic proteins. Terminal repeat analysis of virus DNA from a KS lesion suggests a monoclonal expansion of KSHV in the KS tumor.

Journal ArticleDOI
TL;DR: In this article, the authors examine the value-relevance to investors of financial (accounting) and non-financial information of independent cellular companies and find that, on a stand-alone basis, financial information (earnings, book values, and cash flows) are largely irrelevant for security valuation.

Journal ArticleDOI
TL;DR: This article provides a detailed discussion on reuse partitioning schemes, the effect of handoffs, and prioritization schemes, and other important issues in resource allocation such as overlay cells, frequency planning, and power control.
Abstract: This article provides a detailed discussion of wireless resource and channel allocation schemes. The authors provide a survey of a large number of published papers in the area of fixed, dynamic, and hybrid allocation schemes and compare their trade-offs in terms of complexity and performance. We also investigate these channel allocation schemes based on other factors such as distributed/centralized control and adaptability to traffic conditions. Moreover, we provide a detailed discussion on reuse partitioning schemes, the effect of handoffs, and prioritization schemes. Finally, we discuss other important issues in resource allocation such as overlay cells, frequency planning, and power control.

Journal ArticleDOI
TL;DR: Breast cancer and hormonal contraceptives: Collaborative reanalysis of individual data on 53297 women with breast cancer and 100239 women without breast cancer from 54 epidemiological studies as mentioned in this paper.

Journal ArticleDOI
TL;DR: The authors suggest that procedural and distributive factors interactively combine to influence individuals' reactions to their encounters with other people, groups, and organizations.
Abstract: The authors suggest that procedural and distributive factors interactively combine to influence individuals' reactions to their encounters with other people, groups, and organizations. Results from 45 independent samples (reviewed herein) show that (a) level of procedural justice is more positively related to individuals' reactions when outcome fairness or valence is relatively low and (b) level of outcome fairness or valence is more positively related to individuals' reactions when procedural justice is relatively low. They present various explanations of the interaction effect. Theoretical progress may be achieved through future efforts to delineate the conditions under which each of the explanations is more versus less likely to account for the interaction.

Journal Article
TL;DR: The incidence of gastric cancer varies widely by country and population, with higher rates among the lower socioeconomic groups as discussed by the authors, although rates have generally decreased, there has been a dramatic increase in the incidence of Gastric cancer in the cardia.

Journal ArticleDOI
TL;DR: In this paper, the authors introduce two firm-specific, theory-based constructs: market commonality, developed from the literature on multiple-point competition, and resource similarity, derived from the resource-based theory of the firm.
Abstract: This article bridges two important subjects in strategy: competitor analysis and interfirm rivalry. Through a refined conceptualization of competitor analysis, the article introduces two firm-specific, theory-based constructs: market commonality, developed from the literature on multiple-point competition, and resource similarity, derived from the resource-based theory of the firm. The joint consideration of these two constructs shows the complementarity of these two prominent but contrasting strategy theories. Each firm has a unique market profile and strategic resource endowment, and a pair-wise comparison with a given competitor along these two dimensions will help to illuminate the prebattle competitive tension between these two firms and to predict how a focal firm may interact with each of its competitors. The idea of competitive asymmetry is introduced, that is, the notion that a given pair of firms may not pose an equal degree of threat to each other. To illustrate competitor mapping, measures of ...

Journal ArticleDOI
TL;DR: In this article, a multivariable proportional hazards survival model was developed with the use of data on 80 clinical characteristics from 268 ambulatory patients with advanced congestive heart failure (derivation sample).
Abstract: Background Risk stratification of patients with end-stage congestive heart failure is a critical component of the transplant candidate selection process. Accurate identification of individuals most likely to survive without a transplant would facilitate more efficient use of scarce donor organs. Methods and Results Multivariable proportional hazards survival models were developed with the use of data on 80 clinical characteristics from 268 ambulatory patients with advanced heart failure (derivation sample). Invasive and noninvasive models (with and without catheterization-derived data) were constructed. A prognostic score was determined for each patient from each model. Stratum-specific likelihood ratios were used to develop three prognostic-score risk groups. The models were prospectively validated on 199 similar patients (validation sample) by calculation of the area under the receiver operating characteristic curve for 1-year event-free survival, the censored c-index for event-free survival, and compar...

Journal ArticleDOI
TL;DR: The results demonstrate that CAPE is a potent and a specific inhibitor of NF-kappa B activation and this may provide the molecular basis for its multiple immunomodulatory and antiinflammatory activities.
Abstract: Caffeic acid phenethyl ester (CAPE), an active component of propolis from honeybee hives, is known to have antimitogenic, anticarcinogenic, antiinflammatory, and immunomodulatory properties The molecular basis for these diverse properties is not known Since the role of the nuclear factor NF-kappa B in these responses has been documented, we examined the effect of CAPE on this transcription factor Our results show that the activation of NF-kappa B by tumor necrosis factor (TNF) is completely blocked by CAPE in a dose- and time-dependent manner Besides TNF, CAPE also inhibited NF-kappa B activation induced by other inflammatory agents including phorbol ester, ceramide, hydrogen peroxide, and okadaic acid Since the reducing agents reversed the inhibitory effect of CAPE, it suggests the role of critical sulfhydryl groups in NF-kappa B activation CAPE prevented the translocation of the p65 subunit of NF-kappa B to the nucleus and had no significant effect on TNF-induced I kappa B alpha degradation, but did delay I kappa B alpha resynthesis The effect of CAPE on inhibition of NF-kappa B binding to the DNA was specific, in as much as binding of other transcription factors including AP-1, Oct-1, and TFIID to their DNA were not affected When various synthetic structural analogues of CAPE were examined, it was found that a bicyclic, rotationally constrained, 5,6-dihydroxy form was superactive, whereas 6,7-dihydroxy variant was least active Thus, overall our results demonstrate that CAPE is a potent and a specific inhibitor of NF-kappa B activation and this may provide the molecular basis for its multiple immunomodulatory and antiinflammatory activities

Journal ArticleDOI
TL;DR: Only liquid interfaces will be considered; gas/solid and solid/solid interfaces are not included; this restriction is necessary because of the enormous increase in SH and SF studies in recent years, which makes it extremely difficult to properly discuss the range of work being carried out around the world.
Abstract: A powerful approach to the study of interfaces has been developing rapidly in the past decade. It is based on the spectroscopic methods of second-harmonic (SHG) and sum-frequency generation (SFG). These nonlinear optical techniques, being spectroscopic, provide information at the most fundamental level. A microscopic description of equilibrium and dynamic interface processes requires knowledge of the molecules at the interface, their orientational structure, the energetics that drive chemical and physical processes, and the time scale of molecular motions and relaxation processes. The techniques of second-harmonic and sum-frequency generation have made it possible to selectively probe the chemistry, physics, and biology of gas/liquid, liquid/liquid, liquid/solid, gas/solid, and solid/solid interfaces at the molecular level. In this abbreviated article only liquid interfaces will be considered; gas/solid and solid/solid interfaces are not included. This restriction is necessary because of the enormous increase in SH and SF studies in recent years, which makes it extremely difficult to properly discuss the range of work being carried out around the world. Unfortunately not all of the fine work even in the area of liquid interfaces has been included because of both space and time limitations. A number of review articles are referred to which cover some ofmore » the research material not covered in this article. 99 refs.« less

Journal ArticleDOI
TL;DR: A new calcium-channel blocker, amlodipine, did not increase cardiovascular morbidity or mortality in patients with severe chronic heart failure and the possibility that amlidipine prolongs survival in Patients with nonischemic dilated cardiomyopathy requires further study.
Abstract: Background Previous studies have shown that calcium-channel blockers increase morbidity and mortality in patients with chronic heart failure. We studied the effect of a new calcium-channel blocker, amlodipine, in patients with severe chronic heart failure. Methods We randomly assigned 1153 patients with severe chronic heart failure and ejection fractions of less than 30 percent to double-blind treatment with either placebo (582 patients) or amlodipine (571 patients) for 6 to 33 months, while their usual therapy was continued. The randomization was stratified on the basis of whether patients had ischemic or nonischemic causes of heart failure. The primary end point of the study was death from any cause and hospitalization for major cardiovascular events. Results Primary end points were reached in 42 percent of the placebo group and 39 percent of the amlodipine group, representing a 9 percent reduction in the combined risk of fatal and nonfatal events with amlodipine (95 percent confidence interval, 24 perc...