Showing papers by "Harvard University published in 1988"
TL;DR: The revised criteria for the classification of rheumatoid arthritis (RA) were formulated from a computerized analysis of 262 contemporary, consecutively studied patients with RA and 262 control subjects with rheumatic diseases other than RA (non-RA).
Abstract: The revised criteria for the classification of rheumatoid arthritis (RA) were formulated from a computerized analysis of 262 contemporary, consecutively studied patients with RA and 262 control subjects with rheumatic diseases other than RA (non-RA). The new criteria are as follows: 1) morning stiffness in and around joints lasting at least 1 hour before maximal improvement; 2) soft tissue swelling (arthritis) of 3 or more joint areas observed by a physician; 3) swelling (arthritis) of the proximal interphalangeal, metacarpophalangeal, or wrist joints; 4) symmetric swelling (arthritis); 5) rheumatoid nodules; 6) the presence of rheumatoid factor; and 7) radiographic erosions and/or periarticular osteopenia in hand and/or wrist joints. Criteria 1 through 4 must have been present for at least 6 weeks. Rheumatoid arthritis is defined by the presence of 4 or more criteria, and no further qualifications (classic, definite, or probable) or list of exclusions are required. In addition, a "classification tree" schema is presented which performs equally as well as the traditional (4 of 7) format. The new criteria demonstrated 91-94% sensitivity and 89% specificity for RA when compared with non-RA rheumatic disease control subjects.
19,409 citations
TL;DR: In this paper, the authors propose a theory of ratification in the context of domestic political games and international political games, which is applicable to many other political phenomena, such as dependency, legislative committees, and multiparty coalitions.
Abstract: Domestic politics and international relations are often inextricably entangled, but existing theories (particularly “state-centric” theories) do not adequately account for these linkages. When national leaders must win ratification (formal or informal) from their constituents for an international agreement, their negotiating behavior reflects the simultaneous imperatives of both a domestic political game and an international game. Using illustrations from Western economic summitry, the Panama Canal and Versailles Treaty negotiations, IMF stabilization programs, the European Community, and many other diplomatic contexts, this article offers a theory of ratification. It addresses the role of domestic preferences and coalitions, domestic political institutions and practices, the strategies and tactics of negotiators, uncertainty, the domestic reverberation of international pressures, and the interests of the chief negotiator. This theory of “two-level games” may also be applicable to many other political phenomena, such as dependency, legislative committees, and multiparty coalitions.
6,155 citations
TL;DR: A series of decision-making experiments showed that individuals disproportionately stick with the status quo as mentioned in this paper, that is, doing nothing or maintaining one's current or previous decision, and that this bias is substantial in important real decisions.
Abstract: Most real decisions, unlike those of economics texts, have a status quo alternative—that is, doing nothing or maintaining one's current or previous decision. A series of decision-making experiments shows that individuals disproportionately stick with the status quo. Data on the selections of health plans and retirement programs by faculty members reveal that the status quo bias is substantial in important real decisions. Economics, psychology, and decision theory provide possible explanations for this bias. Applications are discussed ranging from marketing techniques, to industrial organization, to the advance of science.
4,817 citations
TL;DR: The authors provided an analytical treatment of the construct and integrated the diverse approaches to empowerment found in both the management and psychology literatures, identifying certain antecedent conditions of powerlessness and practices that have been hypothesized to empower subordinates.
Abstract: Despite increasing attention on the topic of empowerment, our under-standing of the construct and its underlying processes remains limited. This article addresses these shortcomings by providing an analytical treatment of the construct and by integrating the diverse approaches to empowerment found in both the management and psychology literatures. In addition, the authors identify certain antecedent conditions of powerlessness and practices that have been hypothesized to empower subordinates.
3,796 citations
TL;DR: Perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.
Abstract: Anatomical and physiological observations in monkeys indicate that the primate visual system consists of several separate and independent subdivisions that analyze different aspects of the same retinal image: cells in cortical visual areas 1 and 2 and higher visual areas are segregated into three interdigitating subdivisions that differ in their selectivity for color, stereopsis, movement, and orientation. The pathways selective for form and color seem to be derived mainly from the parvocellular geniculate subdivisions, the depth- and movement-selective components from the magnocellular. At lower levels, in the retina and in the geniculate, cells in these two subdivisions differ in their color selectivity, contrast sensitivity, temporal properties, and spatial resolution. These major differences in the properties of cells at lower levels in each of the subdivisions led to the prediction that different visual functions, such as color, depth, movement, and form perception, should exhibit corresponding differences. Human perceptual experiments are remarkably consistent with these predictions. Moreover, perceptual experiments can be designed to ask which subdivisions of the system are responsible for particular visual abilities, such as figure/ground discrimination or perception of depth from perspective or relative movement--functions that might be difficult to deduce from single-cell response properties.
3,185 citations
TL;DR: The concept of sun-reactive "skin typing" was created in 1975 to be able to classify persons with white skin in order to select the correct initial doses of ultraviolet A (UVA) in the application of the then newly developed technique for the treatment of psoriasis—oral methoxsalen photochemotherapy (PUVA).
Abstract: The concept of sun-reactive "skin typing" was created in 19751for a specific need: to be able to classify personswith white skinin order to select the correct initial doses of ultraviolet A (UVA) (in joules per cubic centimeter) in the application of the then newly developed technique for the treatment of psoriasis—oral methoxsalen photochemotherapy (PUVA).2The need arose as a result of experience with several patients who were a "dark" phenotype (brown or even black hair, and some with brown eyes) but, to our surprise, developed severe phototoxic reactions following oral ingestion of 0.6 mg/kg of methoxsalen and then, two hours later, were exposed to 4 to 6 J/cm2. These initial doses were obviously too high, and it was then understood that the estimation of the white-skinned person's tolerance level to oral PUVA could not be based solely on the phenotype (hair and eye color).
3,030 citations
TL;DR: In this paper, a framework in which goals are proposed to be central determinants of achievement patterns was tested and it was found that learning goals, in which individuals seek to increase their competence, were predicted to promote challenge-seeking and a mastery-oriented response to failure regardless of perceived ability.
Abstract: This study tested a framework in which goals are proposed to be central determinants of achievement patterns. Learning goals, in which individuals seek to increase their competence, were predicted to promote challenge-seeking and a mastery-oriented response to failure regardless of perceived ability. Performance goals, in which individuals seek to gain favorable judgments of their competence or avoid negative judgments, were predicted to produce challenge-avoidance and learned helplessness when perceived ability was low and to promote certain forms of risk-avoidance even when perceived ability was high. Manipulations of relative goal value (learning vs. performance) and perceived ability (high vs. low) resulted in the predicted differences on measures of task choice, performance during difficulty, and spontaneous verbalizations during difficulty. Particularly striking was the way in which the performance goal-low perceived ability condition produced the same pattern of strategy deterioration, failure attribution, and negative affect found in naturally occurring learned helplessness. Implications for theories of motivation and achievement are discussed.
2,462 citations
TL;DR: In this article, two tests for the number of common stochastic trends (i.e., for the order of cointegration) in a multiple time series with and without drift are developed.
Abstract: Cointegrated multiple time series share at least one common trend. Two tests are developed for the number of common stochastic trends (i.e., for the order of cointegration) in a multiple time series with and without drift. Both tests involve the roots of the ordinary least squares coefficient matrix obtained by regressing the series onto its first lag. Critical values for the tests are tabulated, and their power is examined in a Monte Carlo study. Economic time series are often modeled as having a unit root in their autoregressive representation, or (equivalently) as containing a stochastic trend. But both casual observation and economic theory suggest that many series might contain the same stochastic trends so that they are cointegrated. If each of n series is integrated of order 1 but can be jointly characterized by k > n stochastic trends, then the vector representation of these series has k unit roots and n — k distinct stationary linear combinations. Our proposed tests can be viewed alterna...
2,223 citations
TL;DR: Certain environmental signals (i.e., osmolarity and the presence of amino acids) are tightly coupled to the expression of toxR-regulated proteins and therefore may be signals that are directly sensed by the ToxR protein.
Abstract: The toxR gene of Vibrio cholerae encodes a transmembrane, DNA-binding protein that activates transcription of the cholera toxin operon and a gene (tcpA) for the major subunit of a pilus colonization factor. We constructed site-directed insertion mutations in the toxR gene by a novel method employing the chromosomal integration of a mobilizable suicide plasmid containing a portion of the toxR coding sequence. Mutants containing these new toxR alleles had an altered outer membrane protein profile, suggesting that two major outer membrane proteins (OmpT and OmpU) might be under the control of toxR. Physiological studies indicated that varying the concentration of the amino acids asparagine, arginine, glutamate, and serine caused coordinate changes in the expression of cholera toxin, TcpA, OmpT, and OmpU. Changes in the osmolarity of a tryptone-based medium also produced coordinate changes in the expression of these proteins. Other environmental signals (temperature and pH) had a more pronounced effect on the expression of cholera toxin and TcpA than they did on the outer membrane proteins. These results suggest that certain environmental signals (i.e., osmolarity and the presence of amino acids) are tightly coupled to the expression of toxR-regulated proteins and therefore may be signals that are directly sensed by the ToxR protein.
2,066 citations
TL;DR: A three-layered neural network based on interlaminar interactions involving two layers with fixed weights and one layer with adjustable weights finds coefficients for complete conjoint 2-D Gabor transforms without restrictive conditions for image analysis, segmentation, and compression.
Abstract: A three-layered neural network is described for transforming two-dimensional discrete signals into generalized nonorthogonal 2-D Gabor representations for image analysis, segmentation, and compression. These transforms are conjoint spatial/spectral representations, which provide a complete image description in terms of locally windowed 2-D spectral coordinates embedded within global 2-D spatial coordinates. In the present neural network approach, based on interlaminar interactions involving two layers with fixed weights and one layer with adjustable weights, the network finds coefficients for complete conjoint 2-D Gabor transforms without restrictive conditions. In wavelet expansions based on a biologically inspired log-polar ensemble of dilations, rotations, and translations of a single underlying 2-D Gabor wavelet template, image compression is illustrated with ratios up to 20:1. Also demonstrated is image segmentation based on the clustering of coefficients in the complete 2-D Gabor transform. >
1,977 citations
Posted Content•
TL;DR: In this article, the authors explore Rosenstein-Rodman's (1943) idea that simultaneous industrialization of many sectors of the economy can be profitable for all of them, even when no sector can break even industrializing alone.
Abstract: This paper explores Rosenstein-Rodman's (1943) idea that simultaneous industrialization of many sectors of the economy can be profitable for all of them, even when no sector can break even industrializing alone. We analyze this ides in the context of an imperfectly competitive economy with aggregate demand spillovers, and interpret the big push into industrialization as a move from a bad to a good equilibrium. We show that for two equilibria to exist, it must be the case that an industrializing firm raises the demand for products of other sectors through channels other than the contribution of its own profits to demand. For example, a firm paying high factory wages raises demand in other manufacturing sectors even if it loses money. In a similar vein, a firm investing today in order to produce at low cost tomorrow shifts income and hence demand for other goods into the future and so makes it more attractive for other firms also to invest today. Finally, an investing firm can benefit firms in other sectors if it uses a railroad or other shared infrastructure, and hence helps to defray the fixed cost of building the railroad. All these transmission mechanisms that help generate the big push seem to be of some relevance for less developed countries.
TL;DR: In this paper, the authors studied the association between a firm's stock returns and subsequent top management changes and found that there is an inverse relation between the probability of a management change and the firm's share performance.
TL;DR: A specific protein, bound to DNA, can activate transcription of a wide array of genes in many eukaryotes and is controlled by the immune system.
Abstract: A specific protein, bound to DNA, can activate transcription of a wide array of genes in many eukaryotes. Further analysis suggests a general outline for how eukaryotic transcriptional activators function and are controlled.
TL;DR: In this article, the authors investigated whether stock prices are mean-reverting, using data from the United States and 17 other countries, and they found that there is positive and negative autocorrelation in returns over short horizons and negative auto-correlation over longer horizons.
TL;DR: It is speculated that this self-recognition of guanine-rich motifs of DNA serves to bring together, and to zipper up in register, the four homologous chromatids during meiosis.
Abstract: We have discovered that single-stranded DNA containing short guanine-rich motifs will self-associate at physiological salt concentrations to make four-stranded structures in which the strands run in parallel fashion. We believe these complexes are held together by guanines bonded to each other by Hoogsteen pairing. Such guanine-rich sequences occur in immunoglobulin switch regions, in gene promoters, and in chromosomal telomeres. We speculate that this self-recognition of guanine-rich motifs of DNA serves to bring together, and to zipper up in register, the four homologous chromatids during meiosis.
TL;DR: The first use of a complete RFLP linkage map to resolve quantitative traits into discrete Mendelian factors, in an interspecific back-cross of tomato is reported, broadly applicable to the genetic dissection of quantitative inheritance of physiological, morphological and behavioural traits in any higher plant or animal.
Abstract: The conflict between the Mendelian theory of particulate inheritance and the observation of continuous variation for most traits in nature was resolved in the early 1900s by the concept that quantitative traits can result from segregation of multiple genes, modified by environmental effects. Although pioneering experiments showed that linkage could occasionally be detected to such quantitative trait loci (QTLs), accurate and systematic mapping of QTLs has not been possible because the inheritance of an entire genome could not be studied with genetic markers. The use of restriction fragment length polymorphisms (RFLPs) has made such investigations possible, at least in principle. Here, we report the first use of a complete RFLP linkage map to resolve quantitative traits into discrete Mendelian factors, in an interspecific back-cross of tomato. Applying new analytical methods, we mapped at least six QTLs controlling fruit mass, four QTLs for the concentration of soluble solids and five QTLs for fruit pH. This approach is broadly applicable to the genetic dissection of quantitative inheritance of physiological, morphological and behavioural traits in any higher plant or animal.
TL;DR: The complete sequence of the human Duchenne muscular dystrophy cDNA has been determined and dystrophin shares many features with the cytoskeletal protein spectrin and alpha-actinin and is likely to adopt a rod shape about 150 nm in length.
TL;DR: The group differences in peripheral physiological reactions suggest that inherited variation in the threshold of arousal in selected limbic sites may contribute to shyness in childhood and even extreme degrees of social avoidance in adults.
Abstract: The initial behavioral reaction to unfamiliar events is a distinctive source of intraspecific variation in humans and other animals. Two longitudinal studies of 2-year-old children who were extreme in the display of either behavioral restraint or spontaneity in unfamiliar contexts revealed that by 7 years of age a majority of the restrained group were quiet and socially avoidant with unfamiliar children and adults whereas a majority of the more spontaneous children were talkative and interactive. The group differences in peripheral physiological reactions suggest that inherited variation in the threshold of arousal in selected limbic sites may contribute to shyness in childhood and even extreme degrees of social avoidance in adults.
TL;DR: Results are consistent with a model for transformation by SV40 which, at least in part, involves T/p110-114 complex formation and the perturbation of Rb protein and/or T function.
TL;DR: The interaction between E1A and the retinoblastoma gene product is the first demonstration of a physical link between an oncogene and an anti-oncogene.
Abstract: One of the cellular targets implicated in the process of transformation by the adenovirus E1A proteins is a 105K cellular protein. Previously, this protein had been shown to form stable protein/protein complexes with the E1A polypeptides but its identity was unknown. Here, we demonstrate that it is the product of the retinoblastoma gene. The interaction between E1A and the retinoblastoma gene product is the first demonstration of a physical link between an oncogene and an anti-oncogene.
Posted Content•
TL;DR: The concept of cultural capital has been increasingly used in American sociology to study the impact of cultural reproduction on social reproduction as discussed by the authors, however, much confusion surrounds this concept and it is not clear how cultural capital is turned into profits in America.
Abstract: The concept of cultural capital has been increasingly used in American sociology to study the impact of cultural reproduction on social reproduction. However, much confusion surrounds this concept. In this essay, we disentangle Bourdieu and Passeron's original work on cultural capital, specifying the theoretical roles cultural capital plays in their model, and the various types of high status signals they are concerned with. We expand on their work by proposing a new definition of cultural capital which focuses on cultural and social exclusion. We note a number of theoretical ambiguities and gaps in the original model, as well as specific methodological problems. In the second section, we shift our attention to the American literature on cultural capital. We discuss its assumptions and compare it with the original work. We also propose a research agenda which focuses on social and cultural selection and decouples cultural capital from the French context in which it was originally conceived to take into consideration the distinctive features of American culture. This agenda consists in 1) assessing the relevance of the concept of legitimate culture in the U.S.; 2) documenting the distinctive American repertoire of high status cultural signals; and 3) analyzing how cultural capital is turned into profits in America.
TL;DR: It is shown that the hybrid protein (GAL4-VP16) activates transcription unusually efficiently in mammalian cells when bound close to, or at large distances from the gene, and suggested that the activating region of VP16 may be near-maximally potent.
Abstract: Recent work has defined a class of transcriptional activators1–5, members of which activate transcription in yeast, plant, insect and mammalian cells6–9. These proteins contain two parts: one directs DNA binding and the other, called the activating region, presumably interacts with some component of the transcriptional machinery. Activating regions are typically acidic and require some poorly-understood aspect of structure, probably at least in part an α-helix1–5,10. Here we describe a new member of this class, formed by fusing a DNA-binding fragment of the yeast activator GAL4 to a highly acidic portion of the herpes simplex virus protein VP16 (ref. 11; also called Vmw65). VP16 activates transcription of immediate early viral genes by using its amino-terminal sequences to attach to one or more host-encoded proteins that recognise DNA sequences in their promoters11–15. We show that the hybrid protein (GAL4-VP16) activates transcription unusually efficiently in mammalian cells when bound close to, or at large distances from the gene. We suggest that the activating region of VP16 may be near-maximally potent and that it is not coincidental that such a strong activator is encoded by a virus.
TL;DR: A thorough understanding of internal incentive structures is critical to developing a viable theory of the firm, since these incentives determine to a large extent how individuals inside an organization behave as discussed by the authors, and many common features of organizational incentive systems are not easily explained by traditional economic theory.
Abstract: A thorough understanding of internal incentive structures is critical to developing a viable theory of the firm, since these incentives determine to a large extent how individuals inside an organization behave. Many common features of organizational incentive systems are not easily explained by traditional economic theory—including egalitarian pay systems in which compensation is largely independent of performance, the overwhelming use of promotion-based incentive systems, the absence of up-front fees for jobs and effective bonding contracts, and the general reluctance of employers to fire, penalize, or give poor performance evaluations to employees. Typical explanations for these practices offered by behaviorists and practitioners are distinctly uneconomic—focusing on notions such as fairness, equity, morale, trust, social responsibility, and culture. The challenge to economists is to provide viable economic explanations for these practices or to integrate these alternative notions into the traditional economic model.
TL;DR: Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients.
Abstract: Infection with human immunodeficiency virus type 1 (HIV-1) is frequently complicated in its late stages by the AIDS dementia complex, a neurological syndrome characterized by abnormalities in cognition, motor performance, and behavior. This dementia is due partially or wholly to a direct effect of the virus on the brain rather than to opportunistic infection, but its pathogenesis is not well understood. Productive HIV-1 brain infection is detected only in a subset of patients and is confined largely or exclusively to macrophages, microglia, and derivative multinucleated cells that are formed by virus-induced cell fusion. Absence of cytolytic infection of neurons, oligodentrocytes, and astrocytes has focused attention on the possible role of indirect mechanisms of brain dysfunction related to either virus or cell-coded toxins. Delayed development of the AIDS dementia complex, despite both early exposure of the nervous system to HIV-1 and chronic leptomeningeal infection, indicates that although this virus is "neurotropic," it is relatively nonpathogenic for the brain in the absence of immunosuppression. Within the context of the permissive effect of immunosuppression, genetic changes in HIV-1 may underlie the neuropathological heterogeneity of the AIDS dementia complex and its relatively independent course in relation to the systemic manifestations of AIDS noted in some patients.
TL;DR: In this article, the authors review the available equivalence scales and test the sensitivity of various income inequality and poverty measures to choice of equivalence scale using the Luxembourg Income Study (LIS) database.
Abstract: The Luxembourg Income Study (LIS) database on which this article is based offers researchers exciting new possibilities for international comparisons based on household income microdata. Among the choices the LIS microdata allows a researcher, e.g. income definition, income accounting unit, etc., is the choice of family equivalence scale, a method for estimating economic well-being by adjusting income for measurable differences in need.
The range of potential equivalence scales that can and are being used in the ten LIS countries and elsewhere to adjust incomes for size and related differences in need span a wide spectrum. The purpose of this paper is to review the available equivalence scales and to test the sensitivity of various income inequality and poverty measures to choice of equivalence scale using the LIS database. The results of our analysis indicate that choice of equivalence scale can sometimes systematically affect absolute and relative levels of poverty; and inequality and therefore rankings of countries (or population subgroups within countries). Because of these sensitivities, one must carefully consider summary statements and policy implications derived from cross-national comparisons of poverty and/or inequality.
TL;DR: It is postulate that a renal abnormality that contributes to essential hypertension in the general population is a reduced number of nephrons, and congenital variability in filtration surface area may explain why only some, but not all, patients exposed to potentially injurious renal stimuli eventually manifest chronic nephropathy.
TL;DR: The results indicate that the combination of activated oncogene and tissue context are major determinants of malignant progression and that expression of the activated form of c-neu in the mammary epithelium has particularly deleterious consequences.
TL;DR: A molecular mechanism to explain the clinical difference in severity between DMD and BMD patients who bear partial deletions of the same gene locus is presented and is applicable to potential 5' and 3' intron splice mutations and their effect on protein production and clinical phenotype.