Showing papers by "University of Michigan published in 1999"
TL;DR: Blockade of aldosterone receptors by spironolactone, in addition to standard therapy, substantially reduces the risk of both morbidity and death among patients with severe heart failure.
Abstract: Background and Methods Aldosterone is important in the pathophysiology of heart failure. In a double-blind study, we enrolled 1663 patients who had severe heart failure and a left ventricular ejection fraction of no more than 35 percent and who were being treated with an angiotensin-converting–enzyme inhibitor, a loop diuretic, and in most cases digoxin. A total of 822 patients were randomly assigned to receive 25 mg of spironolactone daily, and 841 to receive placebo. The primary end point was death from all causes. Results The trial was discontinued early, after a mean follow-up period of 24 months, because an interim analysis determined that spironolactone was efficacious. There were 386 deaths in the placebo group (46 percent) and 284 in the spironolactone group (35 percent; relative risk of death, 0.70; 95 percent confidence interval, 0.60 to 0.82; P<0.001). This 30 percent reduction in the risk of death among patients in the spironolactone group was attributed to a lower risk of both death from prog...
7,861 citations
TL;DR: In this article, an organic dicarboxylate linker is used in a reaction that gives supertetrahedron clusters when capped with monocarboxyates.
Abstract: Open metal–organic frameworks are widely regarded as promising materials for applications1,2,3,4,5,6,7,8,9,10,11,12,13,14,15 in catalysis, separation, gas storage and molecular recognition. Compared to conventionally used microporous inorganic materials such as zeolites, these organic structures have the potential for more flexible rational design, through control of the architecture and functionalization of the pores. So far, the inability of these open frameworks to support permanent porosity and to avoid collapsing in the absence of guest molecules, such as solvents, has hindered further progress in the field14,15. Here we report the synthesis of a metal–organic framework which remains crystalline, as evidenced by X-ray single-crystal analyses, and stable when fully desolvated and when heated up to 300?°C. This synthesis is achieved by borrowing ideas from metal carboxylate cluster chemistry, where an organic dicarboxylate linker is used in a reaction that gives supertetrahedron clusters when capped with monocarboxylates. The rigid and divergent character of the added linker allows the articulation of the clusters into a three-dimensional framework resulting in a structure with higher apparent surface area and pore volume than most porous crystalline zeolites. This simple and potentially universal design strategy is currently being pursued in the synthesis of new phases and composites, and for gas-storage applications.
6,778 citations
TL;DR: In this paper, the authors conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease, and 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997.
Abstract: Background The extent to which renal allotransplantation — as compared with long-term dialysis — improves survival among patients with end-stage renal disease is controversial, because those selected for transplantation may have a lower base-line risk of death. Methods In an attempt to distinguish the effects of patient selection from those of transplantation itself, we conducted a longitudinal study of mortality in 228,552 patients who were receiving long-term dialysis for end-stage renal disease. Of these patients, 46,164 were placed on a waiting list for transplantation, 23,275 of whom received a first cadaveric transplant between 1991 and 1997. The relative risk of death and survival were assessed with time-dependent nonproportional-hazards analysis, with adjustment for age, race, sex, cause of end-stage renal disease, geographic region, time from first treatment for end-stage renal disease to placement on the waiting list, and year of initial placement on the list. Results Among the various subgroups...
4,442 citations
TL;DR: This article found that when the test was described as producing gender differences and stereotype threat was high, women performed substantially worse than equally qualified men did on difficult (but not easy) math tests among a highly selected sample of men and women.
3,093 citations
TL;DR: The comparison of animal mitochondrial gene arrangements has become a very powerful means for inferring ancient evolutionary relationships, since rearrangements appear to be unique, generally rare events that are unlikely to arise independently in separate evolutionary lineages.
Abstract: Animal mitochondrial DNA is a small, extrachromosomal genome, typically ~16 kb in size. With few exceptions, all animal mitochondrial genomes contain the same 37 genes: two for rRNAs, 13 for proteins and 22 for tRNAs. The products of these genes, along with RNAs and proteins imported from the cytoplasm, endow mitochondria with their own systems for DNA replication, transcription, mRNA processing and translation of proteins. The study of these genomes as they function in mitochondrial systems—‘mitochondrial genomics’— serves as a model for genome evolution. Furthermore, the comparison of animal mitochondrial gene arrangements has become a very powerful means for inferring ancient evolutionary relationships, since rearrangements appear to be unique, generally rare events that are unlikely to arise independently in separate evolutionary lineages. Complete mitochondrial gene arrangements have been published for 58 chordate species and 29 non-chordate species, and partial arrangements for hundreds of other taxa. This review compares and summarizes these gene arrangements and points out some of the questions that may be addressed by comparing mitochondrial systems.
2,923 citations
TL;DR: The human frontal cortex helps mediate working memory, a system that is used for temporary storage and manipulation of information and that is involved in many higher cognitive functions.
Abstract: The human frontal cortex helps mediate working memory, a system that is used for temporary storage and manipulation of information and that is involved in many higher cognitive functions. Working memory includes two components: short-term storage (on the order of seconds) and executive processes that operate on the contents of storage. Recently, these two components have been investigated in functional neuroimaging studies. Studies of storage indicate that different frontal regions are activated for different kinds of information: storage for verbal materials activates Broca's area and left-hemisphere supplementary and premotor areas; storage of spatial information activates the right-hemisphere premotor cortex; and storage of object information activates other areas of the prefrontal cortex. Two of the fundamental executive processes are selective attention and task management. Both processes activate the anterior cingulate and dorsolateral prefrontal cortex.
2,820 citations
TL;DR: In this article, the authors discuss the differentiation of emotions from affect, moods, and attitudes, and outline an appraisal theory of emotions, which is followed by an analysis of the role of arousal in emotions.
Abstract: Emotions are mental states of readiness that arise from appraisals of events or one’s own thoughts. In this article, the authors discuss the differentiation of emotions from affect, moods, and attitudes, and outline an appraisal theory of emotions. Next, various measurement issues are considered. This is followed by an analysis of the role of arousal in emotions. Emotions as markers, mediators, and moderators of consumer responses are then analyzed. The authors turn next to the influence of emotions on cognitive processes, which is followed by a study of the implications of emotions for volitions, goal-directed behavior, and decisions to help. Emotions and customer satisfaction are briefly explored, too. The article closes with a number of questions for future research.
2,787 citations
TL;DR: A clinical diagnostic classification based on a comprehensive review of the literature regarding the sensitivity and specificity of the characteristic clinical features of PD is proposed: Definite, Probable, and Possible.
Abstract: The clinical diagnosis of Parkinson disease (PD) is based on the identification of some combination of the cardinal motor signs of bradykinesia, rigidity, tremor, and postural instability, but few attempts have been made to develop explicit diagnostic criteria. We propose a clinical diagnostic classification based on a comprehensive review of the literature regarding the sensitivity and specificity of the characteristic clinical features of PD. Three levels of diagnostic confidence are differentiated: Definite, Probable, and Possible. The diagnoses of Possible and Probable PD are based on clinical criteria alone. Neuropathologic confirmation is required for the diagnosis of Definite PD in patients with the clinical diagnosis of Possible or Probable PD. Criteria for histopathologic confirmation of PD are also presented.
2,747 citations
TL;DR: Conceptualizations of inertia are seen to underlie the choice to view change as episodic or continuous, whereas continuous change follows the sequence freeze-rebalance-unfreeze.
Abstract: Recent analyses of organizational change suggest a growing concern with the tempo of change, understood as the characteristic rate, rhythm, or pattern of work or activity. Episodic change is contrasted with continuous change on the basis of implied metaphors of organizing, analytic frameworks, ideal organizations, intervention theories, and roles for change agents. Episodic change follows the sequence unfreeze-transition-refreeze, whereas continuous change follows the sequence freeze-rebalance-unfreeze. Conceptualizations of inertia are seen to underlie the choice to view change as episodic or continuous.
2,705 citations
TL;DR: The authors showed that the strong bias in favor of domestic securities is a well-documented characteristic of international investment portfolios, yet the preference for investing close to home also applies to portfolios of domestic stocks.
Abstract: The strong bias in favor of domestic securities is a well-documented characteristic of international investment portfolios, yet we show that the preference for investing close to home also applies to portfolios of domestic stocks. Specifically, U.S. investment managers exhibit a strong preference for locally headquartered firms, particularly small, highly levered firms that produce nontraded goods. These results suggest that asymmetric information between local and nonlocal investors may drive the preference for geographically proximate investments, and the relation between investment proximity and firm size and leverage may shed light on several well-documented asset pricing anomalies.
2,702 citations
TL;DR: In this paper, the authors reviewed the underlying cognitive and communicative processes underlying self-reports, focusing on issues of question comprehension, behavioral frequency reports, and the emergence of context effects in attitude measurement.
Abstract: Self-reports of behaviors and attitudes are strongly influenced by features of the research instrument, including question wording, format, and context. Recent research has addressed the underlying cognitive and communicative processes, which are systematic and increasingly wellunderstood. I review what has been learned, focusing on issues of question comprehension, behavioral frequency reports, and the emergence of context effects in attitude measurement. The accumulating knowledge about the processes underlying self-reports promises to improve questionnaire design and data quality.
TL;DR: What is presently known about the diversity of molecular signaling mechanisms that coordinate the complex ER stress response at the translational and transcriptional level in yeast and in higher eukaryotic cells is summarized.
Abstract: All eukaryotic cells have an extensive membranous labyrinth network of branching tubules and flattened sacs called the endoplasmic reticulum (ER). Approximately one-third of all cellular proteins are translocated into the lumen of the ER where post-translational modification, folding, and oligomerization occurs. The ER provides a unique oxidizing compartment for the folding of membrane and secretory proteins that are destined to the cell surface, as well as for proteins destined to other intracellular organelles, such as lysosomes and the Golgi compartment. Numerous cellular proteins reside within the ER through a mechanism that requires their continuous vesicle-mediated retrieval from post-ER compartments within the early secretory pathway. These ERresident proteins are chaperones and catalysts of protein folding that form a matrix on which newly synthesized proteins attain their final conformation. The ER is also the site of synthesis of cellular lipids and sterols. In addition, the ER is the major signal-transducing organelle within the cell that continuously responds to environmental cues to release calcium. The ER is exquisitely sensitive to alterations in homeostasis, where, upon a variety of different stimuli, signals are transduced from the ER to the cytoplasm and the nucleus to eventually result in adaptation for survival or induction of apoptosis. The immediate response occurs at the translational apparatus, whereas changes in gene expression promote long-term adaptation or apoptotic cell death. Recent evidence supports findings that these signaling pathways influence pathogenesis associated with viral infection and genetic disease. The purpose of this review is to summarize what is presently known about the diversity of molecular signaling mechanisms that coordinate the complex ER stress response at the translational and transcriptional level in yeast and in higher eukaryotic cells.
TL;DR: Alginate may prove to be an ideal material with which to confer specific cellular interactive properties, potentially allowing for the control of long-term gene expression of cells within these matrices.
01 Jan 1999
Harvard University1, McGill University2, University of Birmingham3, University College London4, University of Alabama at Birmingham5, McMaster University6, Dalhousie University7, Anschutz Medical Campus8, Mount Sinai St. Luke's and Mount Sinai Roosevelt9, Hospital for Special Surgery10, University of Michigan11, Detroit Receiving Hospital12, Johns Hopkins University13, Virginia Commonwealth University14, University of Texas at San Antonio15, University of Kiel16, Royal Stoke University Hospital17, University of British Columbia18, Henry Ford Health System19, University of California, Los Angeles20
TL;DR: The American College of Rheumatology Nomenclature for NPSLE provides case definitions for 19 neuropsychiatric syndromes seen in SLE, with reporting standards and recommendations for laboratory and imaging tests.
Abstract: OBJECTIVE
To develop a standardized nomenclature system for the neuropsychiatric syndromes of systemic lupus erythematosus (NPSLE).
METHODS
An international, multidisciplinary committee representing rheumatology, neurology, psychiatry, neuropsychology, and hematology developed case definitions, reporting standards, and diagnostic testing recommendations. Before and after the meeting, clinician committee members assigned diagnoses to sets of vignettes randomly generated from a pool of 108 NPSLE patients. To assess whether the nomenclature system improved diagnostic agreement, a consensus index was developed and pre- and postmeeting scores were compared by t-tests.
RESULTS
Case definitions including diagnostic criteria, important exclusions, and methods of ascertainment were developed for 19 NPSLE syndromes. Recommendations for standard reporting requirements, minimum laboratory evaluation, and imaging techniques were formulated. A short neuropsychological test battery for the diagnosis of cognitive deficits was proposed. In the postmeeting exercise, a statistically significant improvement in diagnostic agreement was observed.
CONCLUSION
The American College of Rheumatology (ACR) Nomenclature for NPSLE provides case definitions for 19 neuropsychiatric syndromes seen in SLE, with reporting standards and recommendations for laboratory and imaging tests. It is intended to facilitate and enhance clinical research, particularly multicenter studies, and reporting. In clinical settings, consultation with other specialists may be required. It should be useful for didactic purposes but should not be used uncritically or as a substitute for a clinical diagnosis. The complete case definitions are available on the ACR World Wide Web site: http://www.rheumatology .org/ar/ar.html.
TL;DR: In the 21st century, manufacturing companies must possess new types of manufacturing systems that are cost-effective and very responsive to all these market changes as mentioned in this paper, which are the cornerstones of this new manufacturing paradigm.
TL;DR: This paper reviewed a wide range of recent attempts in both economics and political science to explain the "resource curse" and found that much has been learned about the economic problems of resource exporters but less is known about their political problems.
Abstract: How does a state's natural resource wealth influence its economic development? For the past fifty years, versions of this question have been explored by both economists and political scientists. New research suggests that resource wealth tends to harm economic growth, yet there is little agreement on why this occurs. This article reviews a wide range of recent attempts in both economics and political science to explain the “resource curse.” It suggests that much has been learned about the economic problems of resource exporters but less is known about their political problems. The disparity between strong findings on economic matters and weak findings on political ones partly reflects the failure of political scientists to carefully test their own theories.
TL;DR: Findings provide evidence that constitutively activated Stat3 signaling contributes to the pathogenesis of multiple myeloma by preventing apoptosis.
TL;DR: In this paper, the authors argue that hazard models are more appropriate for forecasting bankruptcy than the single-period models used previously, and they propose a model that uses a combination of accounting ratios and market-driven variables to produce more accurate out-of-sample forecasts than alternative models.
Abstract: I argue that hazard models are more appropriate for forecasting bankruptcy than the single-period models used previously. Single-period bankruptcy models give biased and inconsistent probability estimates while hazard models produce consistent estimates. I describe a simple technique for estimating a discrete-time hazard model with a logit model estimation program. Applying my technique, I find that about half of the accounting ratios that have been used in previous models are not statistically significant bankruptcy predictors. Moreover, several market-driven variables are strongly related to bankruptcy probability, including market size, past stock returns, and the idiosyncratic standard deviation of stock returns. I propose a model that uses a combination of accounting ratios and market-driven variables to produce more accurate out-of-sample forecasts than alternative models.
TL;DR: In this article, a general framework is presented to understand the relationship between motivation and self-regulated learning according to which can be facilitated by the adoption of mastery and relative ability goals and hindered by adoption of extrinsic goals in addition to positive selfefficacy and task value beliefs.
TL;DR: In this article, the authors examined the potential benefits and risks associated with participation in five types of activities: prosocial (church and volunteer activities), team sports, school involvement, performing arts, and academic clubs.
Abstract: We examined the potential benefits and risks associated with participation in five types of activities: prosocial (church and volunteer activities), team sports, school involvement, performing arts, and academic clubs. Our sample included 1,259 mostly European American adolescents (approximately equal numbers of males and females). First, we explore the link between involvement in these activities and our indicators of positive and negative development. Involvement in prosocial activities was linked to positive educational trajectories and low rates of involvement in risky behaviors. In contrast, participation in team sports was linked to positive educational trajectories and to high rates of involvement in one risky behavior, drinking alcohol. Then, we explore two possible mediators of these associations: peer associations and activity-based identity formation. The evidence supported our hypothesis that group differences in peer associations and activity-based identities help explain activity group diffe...
TL;DR: Experimental results obtained from a large number of benchmarks indicate that application of the proposed conflict analysis techniques to SAT algorithms can be extremely effective for aLarge number of representative classes of SAT instances.
Abstract: This paper introduces GRASP (Generic seaRch Algorithm for the Satisfiability Problem), a new search algorithm for Propositional Satisfiability (SAT). GRASP incorporates several search-pruning techniques that proved to be quite powerful on a wide variety of SAT problems. Some of these techniques are specific to SAT, whereas others are similar in spirit to approaches in other fields of Artificial Intelligence. GRASP is premised on the inevitability of conflicts during the search and its most distinguishing feature is the augmentation of basic backtracking search with a powerful conflict analysis procedure. Analyzing conflicts to determine their causes enables GRASP to backtrack nonchronologically to earlier levels in the search tree, potentially pruning large portions of the search space. In addition, by "recording" the causes of conflicts, GRASP can recognize and preempt the occurrence of similar conflicts later on in the search. Finally, straightforward bookkeeping of the causality chains leading up to conflicts allows GRASP to identify assignments that are necessary for a solution to be found. Experimental results obtained from a large number of benchmarks indicate that application of the proposed conflict analysis techniques to SAT algorithms can be extremely effective for a large number of representative classes of SAT instances.
TL;DR: In this article, the authors present a computational scheme for compressible magnetohydrodynamics (MHD) based on the same elements that make up many modern compressible gas dynamics codes: high-resolution upwinding based on an approximate Riemann solver for MHD and limited reconstruction; an optimally smoothing multi-stage time-stepping scheme; and solution-adaptive refinement and coarsening.
TL;DR: The complex ways in which race and socioeconomic status (SES) combine to affect health are considered, which accounts for much of the observed racial disparities in health.
Abstract: Higher disease rates for blacks (or African Americans) compared to whites are pervasive and persistent over time, with the racial gap in mortality widening in recent years for multiple causes of death. Other racial/ethnic minority populations also have elevated disease risk for some health conditions. This paper considers the complex ways in which race and socioeconomic status (SES) combine to affect health. SES accounts for much of the observed racial disparities in health. Nonetheless, racial differences often persist even at “equivalent” levels of SES. Racism is an added burden for nondominant populations. Individual and institutional discrimination, along with the stigma of inferiority, can adversely affect health by restricting socioeconomic opportunities and mobility. Racism can also directly affect health in multiple ways. Residence in poor neighborhoods, racial bias in medical care, the stress of experiences of discrimination and the acceptance of the societal stigma of inferiority can have deleterious consequences for health.
TL;DR: This report gives an overview of the origins, key concepts, methods, and uses of photovoice as a strategy to enhance women's health.
Abstract: Photovoice is a participatory action research strategy that may offer unique contributions to women's health. It is a process by which people can identify, represent, and enhance their community through a specific photographic technique. Photovoice has three main goals: to enable people (1) to record and reflect their community's strengths and concerns, (2) to promote critical dialogue and knowledge about personal and community issues through large and small group discussion of their photographs, and (3) to reach policymakers. This report gives an overview of the origins, key concepts, methods, and uses of photovoice as a strategy to enhance women's health.
TL;DR: A nonparametric estimation procedure for assessing the probability weighting function and value function at the level of the individual subject, consistent with a growing body of empirical and theoretical work attempting to establish a psychological rationale for the probabilityWeighting function.
TL;DR: A mechanism for acquired arrhythmia is revealed: genetically based reduction in potassium currents that remains clinically silent until combined with additional stressors.
TL;DR: This article found that women are more vulnerable to depressive symptoms than men because they are more likely to experience chronic negative circumstances (or strain), to have a low sense of mastery, and to engage in ruminative coping.
Abstract: It was hypothesized that women are more vulnerable to depressive symptoms than men because they are more likely to experience chronic negative circumstances (or strain), to have a low sense of mastery, and to engage in ruminative coping. The hypotheses were tested in a 2-wave study of approximately 1,100 community-based adults who were 25 to 75 years old. Chronic strain, low mastery, and rumination were each more common in women than in men and mediated the gender difference in depressive symptoms. Rumination amplified the effects of mastery and, to some extent, chronic strain on depressive symptoms. In addition, chronic strain and rumination had reciprocal effects on each other over time, and low mastery also contributed to more rumination. Finally, depressive symptoms contributed to more rumination and less mastery over time.
TL;DR: A review of insights derived from photochemical models and field measurements can be found in this paper, where the ozone-precursor relationship can be understood in terms of a fundamental split into a NOxsenstive and VOC-sensitive (or NOx-saturated) chemical regimes.