Showing papers by "University of Wisconsin-Madison published in 1997"
TL;DR: The 4,639,221-base pair sequence of Escherichia coli K-12 is presented and reveals ubiquitous as well as narrowly distributed gene families; many families of similar genes within E. coli are also evident.
Abstract: The 4,639,221-base pair sequence of Escherichia coli K-12 is presented. Of 4288 protein-coding genes annotated, 38 percent have no attributed function. Comparison with five other sequenced microbes reveals ubiquitous as well as narrowly distributed gene families; many families of similar genes within E. coli are also evident. The largest family of paralogous proteins contains 80 ABC transporters. The genome as a whole is strikingly organized with respect to the local direction of replication; guanines, oligonucleotides possibly related to replication and recombination, and most genes are so oriented. The genome also contains insertion sequence (IS) elements, phage remnants, and many other patches of unusual composition indicating genome plasticity through horizontal transfer.
7,723 citations
TL;DR: This document describes release 2.0 of the SimpleScalar tool set, a suite of free, publicly available simulation tools that offer both detailed and high-performance simulation of modern microprocessors.
Abstract: This document describes release 2.0 of the SimpleScalar tool set, a suite of free, publicly available simulation tools that offer both detailed and high-performance simulation of modern microprocessors. The new release offers more tools and capabilities, precompiled binaries, cleaner interfaces, better documentation, easier installation, improved portability, and higher performance. This paper contains a complete description of the tool set, including retrieval and installation instructions, a description of how to use the tools, a description of the target SimpleScalar architecture, and many details about the internals of the tools and how to customize them. With this guide, the tool set can be brought up and generating results in under an hour (on supported platforms).
3,079 citations
TL;DR: Of the many factors examined that might affect the relation between breast cancer risk and use of HRT, only a woman's weight and body-mass index had a material effect: the increase in the relative risk of breast cancer diagnosed in women using HRT and associated with long durations of use in current and recent users was greater for women of lower than of higher weight or body- mass index.
2,343 citations
TL;DR: This paper presents a development and analysis of the spatial filtering method for localizing sources of brain electrical activity from surface recordings and explores its sensitivity to deviations between actual and assumed data models.
Abstract: A spatial filtering method for localizing sources of brain electrical activity from surface recordings is described and analyzed. The spatial filters are implemented as a weighted sum of the data recorded at different sites. The weights are chosen to minimize the filter output power subject to a linear constraint. The linear constraint forces the filter to pass brain electrical activity from a specified location, while the power minimization attenuates activity originating at other locations. The estimated output power as a function of location is normalized by the estimated noise power as a function of location to obtain a neural activity index map. Locations of source activity correspond to maxima in the neural activity index map. The method does not require any prior assumptions about the number of active sources of their geometry because it exploits the spatial covariance of the source electrical activity. This paper presents a development and analysis of the method and explores its sensitivity to deviations between actual and assumed data models. The effect on the algorithm of covariance matrix estimation, correlation between sources, and choice of reference is discussed. Simulated and measured data is used to illustrate the efficacy of the approach.
2,313 citations
1,976 citations
TL;DR: In this article, transaction cost analysis (TCA) has received considerable attention in the marketing literature over the past decade, and marketing scholars have made important contributions in extending and refining it.
Abstract: Over the past decade, transaction cost analysis (TCA) has received considerable attention in the marketing literature. Marketing scholars have made important contributions in extending and refining...
1,868 citations
TL;DR: The amorphous state is critical in determining the solid-state physical and chemical properties of many pharmaceutical dosage forms and some of the most common methods that can be used to measure them are described.
1,864 citations
TL;DR: Iron-sulfur clusters now rank with such biological prosthetic groups as hemes and flavins in pervasive occurrence and multiplicity of function.
Abstract: Iron-sulfur proteins are found in all life forms. Most frequently, they contain Fe2S2, Fe3S4, and Fe4S4 clusters. These modular clusters undergo oxidation-reduction reactions, may be inserted or removed from proteins, can influence protein structure by preferential side chain ligation, and can be interconverted. In addition to their electron transfer function, iron-sulfur clusters act as catalytic centers and sensors of iron and oxygen. Their most common oxidation states are paramagnetic and present significant challenges for understanding the magnetic properties of mixed valence systems. Iron-sulfur clusters now rank with such biological prosthetic groups as hemes and flavins in pervasive occurrence and multiplicity of function.
1,677 citations
TL;DR: It is estimated that 93% of women and 82% of men with moderate to severe SAS have not been clinically diagnosed and these findings provide a baseline for assessing health care resource needs for sleep apnea.
Abstract: The proportion of sleep apnea syndrome (SAS) in the general adult population that goes undiagnosed was estimated from a sample of 4,925 employed adults. Questionnaire data on doctor-diagnosed sleep apnea were followed up to ascertain the prevalence of diagnosed sleep apnea. In-laboratory polysomnography on a subset of 1,090 participants was used to estimate screen-detected sleep apnea. In this population, without obvious barriers to health care for sleep disorders, we estimate that 93% of women and 82% of men with moderate to severe SAS have not been clinically diagnosed. These findings provide a baseline for assessing health care resource needs for sleep apnea.
1,616 citations
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TL;DR: Practical work in cognitive science and empirical work in memory and language comprehension are reviewed that suggest that it may be possible to investigate connections between topics as disparate as infantile amnesia and mental-model theory.
Abstract: Let's start from scratch in thinking about what memory is for, and consequently, how it works. Suppose that memory and conceptualization work in the service of perception and action. In this case, conceptualization is the encoding of patterns of possible physical interaction with a three-dimensional world. These patterns are constrained by the structure of the environment, the structure of our bodies, and memory. Thus, how we perceive and conceive of the environment is determined by the types of bodies we have. Such a memory would not have associations. Instead, how concepts become related (and what it means to be related) is determined by how separate patterns of actions can be combined given the constraints of our bodies. I call this combination "mesh." To avoid hallucination, conceptualization would normally be driven by the environment, and patterns of action from memory would play a supporting, but automatic, role. A significant human skill is learning to suppress the overriding contribution of the environment to conceptualization, thereby allowing memory to guide conceptualization. The effort used in suppressing input from the environment pays off by allowing prediction, recollective memory, and language comprehension. I review theoretical work in cognitive science and empirical work in memory and language comprehension that suggest that it may be possible to investigate connections between topics as disparate as infantile amnesia and mental-model theory.
1,509 citations
TL;DR: In this article, the basic phenomena that govern the spin exchange process and the physics of angular momentum transfer and loss in optical pumping and spin exchange collisions are discussed. And the authors describe the basic physics of spin exchange and spin-exchange collisions.
Abstract: Spin-exchange optical pumping of mixtures of alkali-metal vapors and noble gases can be used to efficiently polarize the nuclei of the noble-gas atoms. Liters of noble gases at standard temperature and pressure and with nuclear spin polarizations of several tens of percent are now used in many applications. The authors describe the basic phenomena that govern the spin-exchange process and review the physics of angular momentum transfer and loss in optical pumping and spin-exchange collisions.
TL;DR: In this article, the authors collected electroencephalogram (EEG) measures of prefrontal asymmetry and self-report measures of Behavioral Approach and Inhibition System (BAS and BIS) strength, and general levels of positive and negative affect (PA and NA).
Abstract: Resting anterior brain electrical activity, self-report measures of Behavioral Approach and Inhibition System (BAS and BIS) strength, and general levels of positive and negative affect (PA and NA) were collected from 46 unselected undergraduates on two separate occasions Electroencephalogram (EEG) measures of prefrontal asymmetry and the self-report measures showed excellent internal consistency reliability and adequate test-retest stability Aggregate measures across the two assessments were computed for all indices Subjects with greater relative left prefrontal activation reported higher levels of BAS strength, whereas those with greater relative right prefrontal activation reported higher levels of BIS strength Prefrontal EEG asymmetry accounted for more than 25% of the variance in the self-report measure of relative BAS-BIS strength Prefrontal EEG, however, was not significantly correlated with PA or NA, or the relative strength of PA versus NA Posterior asymmetry was unrelated to the self-report measures
TL;DR: The effects of CLA appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.
Abstract: The effects of conjugated linoleic acid (CLA) on body composition were investigated. ICR mice were fed a control diet containing 5.5% corn oil or a CLA-supplemented diet (5.0% corn oil plus 0.5% CLA). Mice fed CLA-supplemented diet exhibited 57% and 60% lower body fat and 5% and 14% increased lean body mass relative to controls (P < 0.05). Total carnitine palmitoyltransferase activity was increased by dietary CLA supplementation in both fat pad and skeletal muscle; the differences were significant for fat pad of fed mice and skeletal muscle of fasted mice. In cultured 3T3-L1 adipocytes CLA treatment (1 x 10(-4)M) significantly reduced heparin-releasable lipoprotein lipase activity (-66%) and the intracellular concentrations of triacylglyceride (-8%) and glycerol (-15%), but significantly increased free glycerol in the culture medium (+22%) compared to control (P < 0.05). The effects of CLA on body composition appear to be due in part to reduced fat deposition and increased lipolysis in adipocytes, possibly coupled with enhanced fatty acid oxidation in both muscle cells and adipocytes.
TL;DR: This paper places the syphilis study within a broader historical and social context to demonstrate that several factors have influenced--and continue to influence--African American's attitudes toward the biomedical community.
Abstract: The Tuskegee Syphilis Study continues to cast its long shadow on the contemporary relationship between African Americans and the biomedical community. Numerous reports have argued that the Tuskegee Syphilis Study is the most important reason why many African Americans distrust the institutions of medicine and public health. Such an interpretation neglects a critical historical point: the mistrust predated public revelations about the Tuskegee study. This paper places the syphilis study within a broader historical and social context to demonstrate that several factors have influenced--and continue to influence--African American's attitudes toward the biomedical community.
TL;DR: Tacrolimus is more effective than cyclosporine in preventing acute rejection in cadaveric renal allograft recipients, and significantly reduces the use of antilymphocyte antibody preparations.
Abstract: Background. Tacrolimus (FK506), a macrolide molecule that potently inhibits the expression of interleukin 2 by T lymphocytes, represents a potential major advance in the management of rejection following solid-organ transplantation. This randomized, open-label study compared the efficacy and safety of tacrolimus-based versus cyclosporine-based immunosuppression in patients receiving cadaveric kidney transplants. Methods. A total of 412 patients were randomized to tacrolimus (n=205) or cyclosporine (n=207) after cadaveric renal transplantation and were followed for 1 year for patient and graft survival and the incidence of acute rejection. Results. One-year patient survival rates were 95.6% for tacrolimus and 96.6% for cyclosporine (P=0.576). Corresponding 1-year graft survival rates were 91.2% and 87.9% (P=0.289). There was a significant reduction in the incidence of biopsy-confirmed acute rejection in the tacrolimus group (30.7%) compared with the cyclosporine group (46.4%, P=0.001), which was confirmed by blinded review, and in the use of antilymphocyte therapy for rejection (10.7% and 25.1%, respectively; P<0.001). Impaired renal function, gastrointestinal disorders, and neurological complications were commonly reported in both treatment groups, but tremor and paresthesia were more frequent in the tacrolimus group. The incidence of posttransplant diabetes mellitus was 19.9% in the tacrolimus group and 4.0% in the cyclosporine group (P<0.001), and was reversible in some patients. Conclusions. Tacrolimus is more effective than cyclosporine in preventing acute rejection in cadaveric renal allograft recipients, and significantly reduces the use of antilymphocyte antibody preparations. Tacrolimus was associated with a higher incidence of neurologic events, which were rarely treatment limiting, and with posttransplant diabetes mellitus, which was reversible in some patients.
Proceedings Article•
08 Dec 1997TL;DR: GreedyDual-Size as discussed by the authors incorporates locality with cost and size concerns in a simple and nonparameterized fashion for high performance, which can potentially improve the performance of main-memory caching of Web documents.
Abstract: Web caches can not only reduce network traffic and downloading latency, but can also affect the distribution of web traffic over the network through cost-aware caching. This paper introduces GreedyDual-Size, which incorporates locality with cost and size concerns in a simple and non-parameterized fashion for high performance. Trace-driven simulations show that with the appropriate cost definition, GreedyDual-Size outperforms existing web cache replacement algorithms in many aspects, including hit ratios, latency reduction and network cost reduction. In addition, GreedyDual-Size can potentially improve the performance of main-memory caching of Web documents.
TL;DR: In this article, the authors describe and illustrate a hermeneutically grounded interpretive framework for deriving marketing-relevant insights from the "texts" of consumer stories.
Abstract: The author describes and illustrates a hermeneutically grounded interpretive framework for deriving marketing-relevant insights from the “texts” of consumer stories and gives an overview of the phi...
TL;DR: It is concluded that CTLA4-Ig and 5C8 can both prevent and reverse acute allografted rejection, significantly prolonging the survival of major histocompatibility complex-mismatched renal allografts in primates without the need for chronic immunosuppression.
Abstract: Selective inhibition of T cell costimulation using the B7-specific fusion protein CTLA4-Ig has been shown to induce long-term allograft survival in rodents. Antibodies preventing the interaction between CD40 and its T cell-based ligand CD154 (CD40L) have been shown in rodents to act synergistically with CTLA4-Ig. It has thus been hypothesized that these agents might be capable of inducing long-term acceptance of allografted tissues in primates. To test this hypothesis in a relevant preclinical model, CTLA4-Ig and the CD40L-specific monoclonal antibody 5C8 were tested in rhesus monkeys. Both agents effectively inhibited rhesus mixed lymphocyte reactions, but the combination was 100 times more effective than either drug alone. Renal allografts were transplanted into nephectomized rhesus monkeys shown to be disparate at major histocompatibility complex class I and class II loci. Control animals rejected in 5–8 days. Brief induction doses of CTLA4-Ig or 5C8 alone significantly prolonged rejection-free survival (20–98 days). Two of four animals treated with both agents experienced extended (>150 days) rejection-free allograft survival. Two animals treated with 5C8 alone and one animal treated with both 5C8 and CTLA4-Ig experienced late, biopsy-proven rejection, but a repeat course of their induction regimen successfully restored normal graft function. Neither drug affected peripheral T cell or B cell counts. There were no clinically evident side effects or rejections during treatment. We conclude that CTLA4-Ig and 5C8 can both prevent and reverse acute allograft rejection, significantly prolonging the survival of major histocompatibility complex-mismatched renal allografts in primates without the need for chronic immunosuppression.
TL;DR: In this paper, the authors integrate the two perspectives and examine their separate and combin-ing perspectives and conclude that "theories of alliance behavior and outcomes have tended to emphasize either partner or relationship characteristics".
Abstract: Theories of alliance behavior and outcomes have tended to emphasize either partner or relationship characteristics. This study integrates the two perspectives and examines their separate and combin...
TL;DR: In this paper, the authors argue that organizational memory affects key new product development processes by influencing the interpretation of incoming information and the performance of new product action routines, and they also argue that memory affects new product actions.
Abstract: Arguing that organizational memory affects key new product development processes by influencing the (1) interpretation of incoming information and (2) the performance of new product action routines
TL;DR: There is a dose-response relationship between sleep-disordered breathing and blood pressure, independent of known confounding factors and this relationship could account for hypertension in a substantial number of adults in the United States.
Abstract: Background: Clinical observations have linked sleepdisordered breathing, a condition of repeated apneas and hypopneas during sleep, with hypertension but evidence for an independent association has been lacking. Understanding this relationship is important because the prevalence of sleep-disordered breathing is high in adults. Objective: To test the hypothesis that sleep-disordered breathing is related to elevated blood pressure independent of confounding factors. Methods: The sample included 1060 employed women and men aged 30 through 60 years who had completed an overnight protocol as part of the Wisconsin Sleep Cohort Study. In-laboratory polysomnography was used to determine sleep-disordered breathing status, quantified as the number of apneas and hypopneas per hour of sleep (apnea-hypopnea index). Blood pressure was measured on the night polysomnography was performed. Results: Blood pressure increased linearly with increasing apnea-hypopnea index (P=.003 for systolic,P=.01 for diastolic, adjusted for confounding factors). The magnitude of the linear association increased with decreasing obesity. At a body mass index (weight in kilograms divided by the square of the height in meters) of 30 kg/m2, an apnea-hypopnea index of 15 (vs 0) was associated with blood pressure increases of 3.6 mm Hg for systolic (95% confidence interval, 1.3-6.0) and 1.8 mm Hg for diastolic (95% confidence interval, 0.3-3.3). The odds ratio for hypertension associated with an apneahypopnea index of 15 (vs 0) was 1.8 (95% confidence interval, 1.3-2.4). Conclusions: There is a dose-response relationship between sleep-disordered breathing and blood pressure, independent of known confounding factors. If causal, the high prevalence of sleep-disordered breathing could account for hypertension in a substantial number of adults in the United States. Arch Intern Med. 1997;157:1746-1752
TL;DR: A comparison of the carbonyl stretching region of γ indomethacin, known to form carboxylic acid dimers, with that of amorphous indometHacin indicated that the amorphously phase exists predominantly as dimers.
Abstract: Purpose. To study the molecular structure of indomethacin-PVP amorphous solid dispersions and identify any specific interactions between the components using vibrational spectroscopy.
TL;DR: This Update summary of physiological and biochemical studies that have contributed to the present understanding of leaf senescence is summarized, current molecular investigations into the regulatory mechanism(s) underlying leafsenescence are discussed, and some molecular approaches toward the manipulation of senescences are reviewed.
Abstract: Leaf senescence is the final stage of leaf development. In forests of deciduous trees, the autumn colors that develop during leaf senescence are of great aesthetic value. This process is also of great practical value because during leaf senescence, nutrients are recycled to other parts of the plant. For example, nitrogen from leaves of deciduous trees is used for the synthesis of storage proteins in stems that will support growth during the following spring (Clausen and Apel, 1991). However, in an agricultural setting, leaf senescence may limit yield in certain crops. Senescence also contributes to the postharvest loss of vegetable crops. Therefore, studying leaf senescence will not only contribute to our knowledge about this fundamental developmental process, but may also lead to ways of manipulating senescence for agricultural applications. There have been many physiological, biochemical, and molecular studies of leaf senescence. These studies show that during senescence leaf cells undergo highly coordinated changes in cell structure, metabolism, and gene expression. The earliest and most significant change in cell structure is the breakdown of the chloroplast, the organelle that contains up to 70% of the leaf protein. Metabolically, carbon assimilation (photosynthesis) is replaced by catabolism of chlorophyll and macromolecules such as proteins, membrane lipids, and RNA so that some of the released nutrients can be recycled. At the molecular level, these changes are accompanied by, or perhaps driven by, changes in gene expression. In this Update, we summarize physiological and biochemical studies that have contributed to the present understanding of leaf senescence, then we discuss current molecular investigations into the regulatory mechanism(s) underlying leaf senescence, and, finally, we review some molecular approaches toward the manipulation of leaf senescence.
01 May 1997
TL;DR: A microarchitecture that simplifies wakeup and selection logic is proposed and discussed, which will help minimize performance degradation due to slow bypasses in future wide-issue machines.
Abstract: The performance tradeoff between hardware complexity and clock speed is studied. First, a generic superscalar pipeline is defined. Then the specific areas of register renaming, instruction window wakeup and selection logic, and operand bypassing are analyzed. Each is modeled and Spice simulated for feature sizes of 0.8µm, 0.35µm, and 0.18µm. Performance results and trends are expressed in terms of issue width and window size. Our analysis indicates that window wakeup and selection logic as well as operand bypass logic are likely to be the most critical in the future.A microarchitecture that simplifies wakeup and selection logic is proposed and discussed. This implementation puts chains of dependent instructions into queues, and issues instructions from multiple queues in parallel. Simulation shows little slowdown as compared with a completely flexible issue window when performance is measured in clock cycles. Furthermore, because only instructions at queue heads need to be awakened and selected, issue logic is simplified and the clock cycle is faster --- consequently overall performance is improved. By grouping dependent instructions together, the proposed microarchitecture will help minimize performance degradation due to slow bypasses in future wide-issue machines.
TL;DR: There are both common and unique components of the neural networks mediating pleasant and unpleasant emotion in healthy women that are consistent with those from other recent PET studies of human emotion.
TL;DR: This study provides the first direct evidence that physician intervention with problem drinkers decreases alcohol use and health resource utilization in the US health care system.
Abstract: Objective. —Project TrEAT (Trial for Early Alcohol Treatment) was designed to test the efficacy of brief physician advice in reducing alcohol use and health care utilization in problem drinkers. Design. —Randomized controlled clinical trial with 12-month follow-up. Setting. —A total of 17 community-based primary care practices (64 physicians) located in 10 Wisconsin counties. Participants. —Of the 17 695 patients screened for problem drinking, 482 men and 292 women met inclusion criteria and were randomized into a control (n=382) or an experimental (n=392) group. A total of 723 subjects (93%) participated in the 12-month follow-up procedures. Intervention. —The intervention consisted of two 10- to 15-minute counseling visits delivered by physicians using a scripted workbook that included advice, education, and contracting information. Main Outcome Measures. —Alcohol use measures, emergency department visits, and hospital days. Results. —There were no significant differences between groups at baseline on alcohol use, age, socioeconomic status, smoking status, rates of depression or anxiety, frequency of conduct disorders, lifetime drug use, or health care utilization. At the time of the 12-month follow-up, there were significant reductions in 7-day alcohol use (mean number of drinks in previous 7 days decreased from 19.1 at baseline to 11.5 at 12 months for the experimental group vs 18.9 at baseline to 15.5 at 12 months for controls;t=4.33;P Conclusions. —This study provides the first direct evidence that physician intervention with problem drinkers decreases alcohol use and health resource utilization in the US health care system.
TL;DR: The atomic nature of the most important kinetic mechanisms of film growth is explored, which include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport.
Abstract: Growth of thin films from atoms deposited from the gas phase is intrinsically a nonequilibrium phenomenon governed by a competition between kinetics and thermodynamics. Precise control of the growth and thus of the properties of deposited films becomes possible only after an understanding of this competition is achieved. Here, the atomic nature of the most important kinetic mechanisms of film growth is explored. These mechanisms include adatom diffusion on terraces, along steps, and around island corners; nucleation and dynamics of the stable nucleus; atom attachment to and detachment from terraces and islands; and interlayer mass transport. Ways to manipulate the growth kinetics in order to select a desired growth mode are briefly addressed.
TL;DR: An efficient and scalable data clustering method is proposed, based on a new in-memory data structure called CF-tree, which serves as an in- memory summary of the data distribution, and implemented in a system called BIRCH (Balanced Iterative Reducing and Clustering using Hierarchies), and compared with other available methods.
Abstract: Data clustering is an important technique for exploratory data analysis, and has been studied for several years. It has been shown to be useful in many practical domains such as data classification and image processing. Recently, there has been a growing emphasis on exploratory analysis of very large datasets to discover useful patterns and/or correlations among attributes. This is called data mining, and data clustering is regarded as a particular branch. However existing data clustering methods do not adequately address the problem of processing large datasets with a limited amount of resources (e.g., memory and cpu cycles). So as the dataset size increases, they do not scale up well in terms of memory requirement, running time, and result quality.
In this paper, an efficient and scalable data clustering method is proposed, based on a new in-memory data structure called CF-tree, which serves as an in-memory summary of the data distribution. We have implemented it in a system called BIRCH (Balanced Iterative Reducing and Clustering using Hierarchies), and studied its performance extensively in terms of memory requirements, running time, clustering quality, stability and scalability; we also compare it with other available methods. Finally, BIRCH is applied to solve two real-life problems: one is building an iterative and interactive pixel classification tool, and the other is generating the initial codebook for image compression.
TL;DR: In this paper, a new set of prestige and socioeconomic indexes for 1990 Census occupation lines was proposed, based on relationships between the prestige ratings obtained by Nakao and Treas in the 1989 General Social Survey and characteristics of occupational incumbents in the 1990 Census.
Abstract: Following a review of the history and sources of socioeconomic indexes for occupations, we estimate a new set of indexes for 1990 Census occupation lines, based on relationships between the prestige ratings obtained by Nakao and Treas in the 1989 General Social Survey and characteristics of occupational incumbents in the 1990 Census. We also investigate theoretical and empirical relationships among socioeconomic and prestige indexes, using data from the 1994 General Social Survey. Many common occupations, especially those held by women, do not fit the typical relationships among prestige, education, and earnings. The fit between prestige and socioeconomic characteristics of occupations can be improved by statistical transformation of the variables. However, in rudimentary models of occupational stratification, prestige-validated socioeconomic indexes are of limited value. They give too much weight to occupational earnings, and they ignore intergenerational relationships between occupational education and occupational earnings. Levels of occupational education appear to define the main dimension of occupational persistence across and within generations. We conclude that composite indexes of occupational socioeconomic status are scientifically obsolete.