Showing papers by "University of Michigan published in 2004"
TL;DR: It is demonstrated that the algorithms proposed are highly effective at discovering community structure in both computer-generated and real-world network data, and can be used to shed light on the sometimes dauntingly complex structure of networked systems.
Abstract: We propose and study a set of algorithms for discovering community structure in networks-natural divisions of network nodes into densely connected subgroups. Our algorithms all share two definitive features: first, they involve iterative removal of edges from the network to split it into communities, the edges removed being identified using any one of a number of possible "betweenness" measures, and second, these measures are, crucially, recalculated after each removal. We also propose a measure for the strength of the community structure found by our algorithms, which gives us an objective metric for choosing the number of communities into which a network should be divided. We demonstrate that our algorithms are highly effective at discovering community structure in both computer-generated and real-world network data, and show how they can be used to shed light on the sometimes dauntingly complex structure of networked systems.
12,882 citations
TL;DR: Although considerable improvement has occurred in the process of care for patients with ST-elevation myocardial infarction (STEMI), room for improvement exists as discussed by the authors, and the purpose of the present guideline is to focus on the numerous advances in the diagnosis and management of patients
Abstract: Although considerable improvement has occurred in the process of care for patients with ST-elevation myocardial infarction (STEMI), room for improvement exists.[1–3][1][][2][][3] The purpose of the present guideline is to focus on the numerous advances in the diagnosis and management of patients
8,352 citations
TL;DR: The concept of school engagement has attracted increasing attention as representing a possible antidote to declining academic motivation and achievement as mentioned in this paper, and it is presumed to be malleable, responsive to contextual features, and amenable to environmental change.
Abstract: The concept of school engagement has attracted increasing attention as representing a possible antidote to declining academic motivation and achievement. Engagement is presumed to be malleable, responsive to contextual features, and amenable to environmental change. Researchers describe behavioral, emotional, and cognitive engagement and recommend studying engagement as a multifaceted construct. This article reviews definitions, measures, precursors, and outcomes of engagement; discusses limitations in the existing research; and suggests improvements. The authors conclude that, although much has been learned, the potential contribution of the concept of school engagement to research on student experience has yet to be realized. They call for richer characterizations of how students behave, feel, and think—research that could aid in the development of finely tuned interventions
7,641 citations
Journal Article•
TL;DR: Elliott M. Antman,MD, FACC, FAHA, Chair; Daniel T. Anbe, MD, F ACC,FAHA; Paul Wayne Armstrong, MD; Eric R. Bates; Lee A. Green; Mary Hand; Judith S. Kushner; and Sidney C. Sloan.
7,134 citations
TL;DR: A hierarchical agglomeration algorithm for detecting community structure which is faster than many competing algorithms: its running time on a network with n vertices and m edges is O (md log n) where d is the depth of the dendrogram describing the community structure.
Abstract: The discovery and analysis of community structure in networks is a topic of considerable recent interest within the physics community, but most methods proposed so far are unsuitable for very large networks because of their computational cost. Here we present a hierarchical agglomeration algorithm for detecting community structure which is faster than many competing algorithms: its running time on a network with n vertices and m edges is O (md log n) where d is the depth of the dendrogram describing the community structure. Many real-world networks are sparse and hierarchical, with m approximately n and d approximately log n, in which case our algorithm runs in essentially linear time, O (n log(2) n). As an example of the application of this algorithm we use it to analyze a network of items for sale on the web site of a large on-line retailer, items in the network being linked if they are frequently purchased by the same buyer. The network has more than 400 000 vertices and 2 x 10(6) edges. We show that our algorithm can extract meaningful communities from this network, revealing large-scale patterns present in the purchasing habits of customers.
6,599 citations
Thomas Jefferson University1, Cincinnati Children's Hospital Medical Center2, Yeshiva University3, Alfred I. duPont Hospital for Children4, University of Michigan5, Harvard University6, University of Iowa7, Mayo Clinic8, University of Texas Health Science Center at Houston9, Wake Forest University10, University of Minnesota11, University of Pennsylvania12, National Institutes of Health13, American Institutes for Research14
5,707 citations
TL;DR: The meaning of value and the process of value creation are rapidly shifting from a product-and firm-centric view to personalized consumer experiences as discussed by the authors, and consumers are increasingly co-creating value with the firm.
5,141 citations
TL;DR: An algorithm is described which gives excellent results when tested on both computer-generated and real-world networks and is much faster, typically thousands of times faster, than previous algorithms.
Abstract: Many networks display community structure--groups of vertices within which connections are dense but between which they are sparser--and sensitive computer algorithms have in recent years been developed for detecting this structure. These algorithms, however, are computationally demanding, which limits their application to small networks. Here we describe an algorithm which gives excellent results when tested on both computer-generated and real-world networks and is much faster, typically thousands of times faster, than previous algorithms. We give several example applications, including one to a collaboration network of more than 50,000 physicists.
5,127 citations
TL;DR: The number of circulating tumor cells before treatment is an independent predictor of progression-free survival and overall survival in patients with metastatic breast cancer.
Abstract: Metastatic breast cancer (MBC) is considered incurable; therefore, palliative treatment is the only option. The biologic heterogeneity of the disease is reflected in its somewhat unpredictable clinical behavior. The presence of circulating tumor cells (CTCs) in patients with MBC about to start a new line of treatment has been shown to predict progression-free and overall survival. This prognostic value is independent of the line of therapy (eg, first or second line). Moreover, a multivariate analysis has shown the prognostic value of CTCs to be superior to that of site of metastasis, type of therapy, and length of time to recurrence after definitive primary surgery. These data suggest that the presence of CTCs may be used to modify the staging system for advanced disease. Larger studies are needed to confirm these data and evaluate the use of CTC detection in monitoring treatment and furthering our understanding of breast cancer biology when combined with other diagnostic technologies.
4,244 citations
Massachusetts Institute of Technology1, University of Pennsylvania2, Princeton University3, New York University4, Los Alamos National Laboratory5, Fermilab6, University of Chicago7, Ohio State University8, University of Arizona9, Drexel University10, Johns Hopkins University11, University of Pittsburgh12, Carnegie Mellon University13, New Mexico State University14, Spanish National Research Council15, University of Sussex16, University of Tokyo17, United States Department of the Navy18, University of Michigan19, Rochester Institute of Technology20, Pennsylvania State University21
TL;DR: In this paper, the authors measured cosmological parameters using the three-dimensional power spectrum P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with WMAP and other data.
Abstract: We measure cosmological parameters using the three-dimensional power spectrum P(k) from over 200,000 galaxies in the Sloan Digital Sky Survey (SDSS) in combination with WMAP and other data. Our results are consistent with a "vanilla" flat adiabaticCDM model without tilt (ns = 1), running tilt, tensor modes or massive neutrinos. Adding SDSS information more than halves the WMAP-only error bars on some parameters, tightening 1� constraints on the Hubble parameter from h � 0.74 +0.18 −0.07 to h � 0.70 +0.04 −0.03, on the matter density from m � 0.25 ± 0.10 to m � 0.30 ± 0.04 (1�) and on neutrino masses from < 11 eV to < 0.6 eV (95%). SDSS helps even more when dropping prior assumptions about curvature, neutrinos, tensor modes and the equation of state. Our results are in substantial agreement with the joint analysis of WMAP and the 2dF Galaxy Redshift Survey, which is an impressive consistency check with independent redshift survey data and analysis techniques. In this paper, we place particular emphasis on clarifying the physical origin of the constraints, i.e., what we do and do not know when using different data sets and prior assumptions. For instance, dropping the assumption that space is perfectly flat, the WMAP-only constraint on the measured age of the Universe tightens from t0 � 16.3 +2.3
3,938 citations
TL;DR: This review summarizes the current knowledge about the molecular machinery of autophagy and the role of the autophagic machinery in eukaryotic development and identifies a set of evolutionarily conserved genes that are essential forAutophagy.
Columbia University1, University of Michigan2, University of California, Davis3, Baylor College of Medicine4, University of Massachusetts Medical School5, Mayo Clinic6, University of Washington7, University of Arkansas for Medical Sciences8, University of California, San Francisco9, Cleveland Clinic10, University of Colorado Denver11
TL;DR: The improvement in median survival of nearly two months with docetaxel and estramustine, as compared with mitoxantrone and prednisone, provides support for this approach in men with metastatic, androgen-independent prostate cancer.
Abstract: background Mitoxantrone-based chemotherapy palliates pain without extending survival in men with progressive androgen-independent prostate cancer. We compared docetaxel plus estramustine with mitoxantrone plus prednisone in men with metastatic, hormoneindependent prostate cancer. methods We randomly assigned 770 men to one of two treatments, each given in 21-day cycles: 280 mg of estramustine three times daily on days 1 through 5, 60 mg of docetaxel per square meter of body-surface area on day 2, and 60 mg of dexamethasone in three divided doses before docetaxel, or 12 mg of mitoxantrone per square meter on day 1 plus 5 mg of prednisone twice daily. The primary end point was overall survival; secondary end points were progression-free survival, objective response rates, and post-treatment declines of at least 50 percent in serum prostate-specific antigen (PSA) levels. results Of 674 eligible patients, 338 were assigned to receive docetaxel and estramustine and 336 to receive mitoxantrone and prednisone. In an intention-to-treat analysis, the median overall survival was longer in the group given docetaxel and estramustine than in the group given mitoxantrone and prednisone (17.5 months vs. 15.6 months, P=0.02 by the log-rank test), and the corresponding hazard ratio for death was 0.80 (95 percent confidence interval, 0.67 to 0.97). The median time to progression was 6.3 months in the group given docetaxel and estramustine and 3.2 months in the group given mitoxantrone and prednisone (P<0.001 by the log-rank test). PSA declines of at least 50 percent occurred in 50 percent and 27 percent of patients, respectively (P<0.001), and objective tumor responses were observed in 17 percent and 11 percent of patients with bidimensionally measurable disease, respectively (P=0.30). Grade 3 or 4 neutropenic fevers (P=0.01), nausea and vomiting (P<0.001), and cardiovascular events (P=0.001) were more common among patients receiving docetaxel and estramustine than among those receiving mitoxantrone and prednisone. Pain relief was similar in both groups. conclusions The improvement in median survival of nearly two months with docetaxel and estramustine, as compared with mitoxantrone and prednisone, provides support for this approach in men with metastatic, androgen-independent prostate cancer.
TL;DR: ONCOMINE is presented, a cancer microarray database and web-based data-mining platform aimed at facilitating discovery from genome-wide expression analyses and novel biomarkers and therapeutic targets are discovered.
TL;DR: In this paper, the authors examined responses to land use under different management strategies and that employs response variables that have greater diagnostic value than many of the aggregated measures in current use.
Abstract: ▪ Abstract Local habitat and biological diversity of streams and rivers are strongly influenced by landform and land use within the surrounding valley at multiple scales. However, empirical associations between land use and stream response only varyingly succeed in implicating pathways of influence. This is the case for a number of reasons, including (a) covariation of anthropogenic and natural gradients in the landscape; (b) the existence of multiple, scale-dependent mechanisms; (c) nonlinear responses; and (d) the difficulties of separating present-day from historical influences. Further research is needed that examines responses to land use under different management strategies and that employs response variables that have greater diagnostic value than many of the aggregated measures in current use. In every respect, the valley rules the stream. H.B.N. Hynes (1975)
TL;DR: It is suggested that PDL contains stem cells that have the potential to generate cementum/PDL-like tissue in vivo and transplantation of these cells might hold promise as a therapeutic approach for reconstruction of tissues destroyed by periodontal diseases.
TL;DR: Mediational analyses revealed that the experience of positive emotions contributed, in part, to participants' abilities to achieve efficient emotion regulation, demonstrated by accelerated cardiovascular recovery from negative emotional arousal and by finding positive meaning in negative circumstances.
Abstract: Theory indicates that resilient individuals “bounce back” from stressful experiences quickly and effectively. Few studies, however, have provided empirical evidence for this theory. The broaden-and-build theory of positive emotions (B. L. Fredrickson, 1998, 2001) is used as a framework for understanding psychological resilience. The authors used a multimethod approach in 3 studies to predict that resilient people use positive emotions to rebound from, and find positive meaning in, stressful encounters. Mediational analyses revealed that the experience of positive emotions contributed, in part, to participants’ abilities to achieve efficient emotion regulation, demonstrated by accelerated cardiovascular recovery from negative emotional arousal (Studies 1 and 2) and by finding positive meaning in negative circumstances (Study 3). Implications for research on resilience and positive emotions are discussed.
TL;DR: The DRM's utility is shown by documenting close correspondences between the DRM reports of 909 employed women and established results from experience sampling, and an analysis of the hedonic treadmill shows its potential for well-being research.
Abstract: The Day Reconstruction Method (DRM) assesses how people spend their time and how they experience the various activities and settings of their lives, combining features of time-budget measurement and experience sampling. Participants systematically reconstruct their activities and experiences of the preceding day with procedures designed to reduce recall biases. The DRM's utility is shown by documenting close correspondences between the DRM reports of 909 employed women and established results from experience sampling. An analysis of the hedonic treadmill shows the DRM's potential for well-being research.
TL;DR: In the temperature range 600 to 900 kelvin, the AgPbmSbTe2+m material is expected to outperform all reported bulk thermoelectrics, thereby earmarking it as a material system for potential use in efficient thermoeLECTric power generation from heat sources.
Abstract: The conversion of heat to electricity by thermoelectric devices may play a key role in the future for energy production and utilization. However, in order to meet that role, more efficient thermoelectric materials are needed that are suitable for high-temperature applications. We show that the material system AgPb m SbTe 2+ m may be suitable for this purpose. With m = 10 and 18 and doped appropriately, n -type semiconductors can be produced that exhibit a high thermoelectric figure of merit material ZT max of ∼2.2 at 800 kelvin. In the temperature range 600 to 900 kelvin, the AgPb m SbTe 2+ m material is expected to outperform all reported bulk thermoelectrics, thereby earmarking it as a material system for potential use in efficient thermoelectric power generation from heat sources.
TL;DR: In this article, a case study of Islam and politics in post-communist Europe and the United States is presented, focusing on the theory of existential security and the consequences of Secularization.
Abstract: Part I. Understanding Secularization: 1. The secularization debate 2. Measuring secularization 3. Comparing secularization worldwide Part II. Case Studies of Religion and Politics: 4. The puzzle of secularization in the United States and Western Europe 5. A religious revival in post-communist Europe? 6. Religion and politics in the Muslim world Part III. The Consequences of Secularization: 7. Religion, the Protestant ethic, and moral values 8. Religious organizations and social capital 9. Religious parties and electoral behavior Part IV. Conclusions: 10. Secularization and its consequences 11. Re-examining the theory of existential security 12. Re-examining evidence for the security thesis.
TL;DR: The design, synthesis and properties of crystalline Zn4O(1,3,5-benzenetribenzoate)2 are reported, a new metal-organic framework with a surface area estimated at 4,500 m2 g-1 that combines this exceptional level of surface area with an ordered structure that has extra-large pores capable of binding polycyclic organic guest molecules.
Abstract: One of the outstanding challenges in the field of porous materials is the design and synthesis of chemical structures with exceptionally high surface areas Such materials are of critical importance to many applications involving catalysis, separation and gas storage The claim for the highest surface area of a disordered structure is for carbon, at 2,030 m2 g(-1) (ref 2) Until recently, the largest surface area of an ordered structure was that of zeolite Y, recorded at 904 m2 g(-1) (ref 3) But with the introduction of metal-organic framework materials, this has been exceeded, with values up to 3,000 m2 g(-1) (refs 4-7) Despite this, no method of determining the upper limit in surface area for a material has yet been found Here we present a general strategy that has allowed us to realize a structure having by far the highest surface area reported to date We report the design, synthesis and properties of crystalline Zn4O(1,3,5-benzenetribenzoate)2, a new metal-organic framework with a surface area estimated at 4,500 m2 g(-1) This framework, which we name MOF-177, combines this exceptional level of surface area with an ordered structure that has extra-large pores capable of binding polycyclic organic guest molecules--attributes not previously combined in one material
TL;DR: A review of the synthesis, structure, and properties of metal-organic frameworks (MOFs) is presented in this paper, highlighting the important advances in their research over the past decade.
TL;DR: Blood pressure was reduced by both treatments, but the effects of the amlodipine-based regimen were more pronounced, especially in the early period, which emphasise the importance of prompt blood-pressure control in hypertensive patients at high cardiovascular risk.
TL;DR: It is pointed out that weighted networks can in many cases be analyzed using a simple mapping from a weighted network to an unweighted multigraph, allowing us to apply standard techniques for unweighting graphs to weighted ones as well.
Abstract: The connections in many networks are not merely binary entities, either present or not, but have associated weights that record their strengths relative to one another. Recent studies of networks have, by and large, steered clear of such weighted networks, which are often perceived as being harder to analyze than their unweighted counterparts. Here we point out that weighted networks can in many cases be analyzed using a simple mapping from a weighted network to an unweighted multigraph, allowing us to apply standard techniques for unweighted graphs to weighted ones as well. We give a number of examples of the method, including an algorithm for detecting community structure in weighted networks and a simple proof of the maximum-flow--minimum-cut theorem.
TL;DR: LexRank as discussed by the authors is a stochastic graph-based method for computing relative importance of textual units for Natural Language Processing (NLP), which is based on the concept of eigenvector centrality.
Abstract: We introduce a stochastic graph-based method for computing relative importance of textual units for Natural Language Processing. We test the technique on the problem of Text Summarization (TS). Extractive TS relies on the concept of sentence salience to identify the most important sentences in a document or set of documents. Salience is typically defined in terms of the presence of particular important words or in terms of similarity to a centroid pseudo-sentence. We consider a new approach, LexRank, for computing sentence importance based on the concept of eigenvector centrality in a graph representation of sentences. In this model, a connectivity matrix based on intra-sentence cosine similarity is used as the adjacency matrix of the graph representation of sentences. Our system, based on LexRank ranked in first place in more than one task in the recent DUC 2004 evaluation. In this paper we present a detailed analysis of our approach and apply it to a larger data set including data from earlier DUC evaluations. We discuss several methods to compute centrality using the similarity graph. The results show that degree-based methods (including LexRank) outperform both centroid-based methods and other systems participating in DUC in most of the cases. Furthermore, the LexRank with threshold method outperforms the other degree-based techniques including continuous LexRank. We also show that our approach is quite insensitive to the noise in the data that may result from an imperfect topical clustering of documents.
TL;DR: This chapter reviews the latest empirical evidence supporting the broaden-and-build theory and draws out implications the theory holds for optimizing health and well-being.
Abstract: The broaden-and-build theory describes the form and function of a subset of positive emotions, including joy, interest, contentment and love. A key proposition is that these positive emotions broaden an individual's momentary thought-action repertoire: joy sparks the urge to play, interest sparks the urge to explore, contentment sparks the urge to savour and integrate, and love sparks a recurring cycle of each of these urges within safe, close relationships. The broadened mindsets arising from these positive emotions are contrasted to the narrowed mindsets sparked by many negative emotions (i.e. specific action tendencies, such as attack or flee). A second key proposition concerns the consequences of these broadened mindsets: by broadening an individual's momentary thought-action repertoire--whether through play, exploration or similar activities--positive emotions promote discovery of novel and creative actions, ideas and social bonds, which in turn build that individual's personal resources; ranging from physical and intellectual resources, to social and psychological resources. Importantly, these resources function as reserves that can be drawn on later to improve the odds of successful coping and survival. This chapter reviews the latest empirical evidence supporting the broaden-and-build theory and draws out implications the theory holds for optimizing health and well-being.
TL;DR: In this article, a conceptual framework for assessing student motivation and self-regulated learning in the college classroom is presented, which is based on a self-regulatory perspective on student motivation in contrast to a student approaches to learning.
Abstract: A conceptual framework for assessing student motivation and self-regulated learning in the college classroom is presented. The framework is based on a self-regulatory (SRL) perspective on student motivation and learning in contrast to a student approaches to learning (SAL) perspective. The differences between SRL and SAL approaches are discussed, as are the implications of the SRL conceptual framework for developing instruments to assess college student motivation and learning. The conceptual framework may be useful in guiding future research on college student motivation and learning.
TL;DR: The purpose of this statement is to provide healthcare professionals and regulatory agencies with a comprehensive review of the literature on air pollution and cardiovascular disease and practical recommendations for healthcare providers and their patients are outlined.
Abstract: Air pollution is a heterogeneous, complex mixture of gases, liquids, and particulate matter. Epidemiological studies have demonstrated a consistent increased risk for cardiovascular events in relation to both short- and long-term exposure to present-day concentrations of ambient particulate matter. Several plausible mechanistic pathways have been described, including enhanced coagulation/thrombosis, a propensity for arrhythmias, acute arterial vasoconstriction, systemic inflammatory responses, and the chronic promotion of atherosclerosis. The purpose of this statement is to provide healthcare professionals and regulatory agencies with a comprehensive review of the literature on air pollution and cardiovascular disease. In addition, the implications of these findings in relation to public health and regulatory policies are addressed. Practical recommendations for healthcare providers and their patients are outlined. In the final section, suggestions for future research are made to address a number of remaining scientific questions.
TL;DR: This work proposes that aesthetic pleasure is a funnction of the perceiver's processing dynamics: the more fluently perceivers can process an object, the more positive their aesthetic response, and reviews variables known to influence aesthetic judgments, and traces their effects to changes in processing fluency.
Abstract: We propose that aesthetic pleasure is a function of the perceiver’s processing dynamics: The more fluently perceivers can process an object, the more positive their aesthetic response. We review variables known to influence aesthetic judgments, such as figural goodness, figure–ground contrast, stimulus repetition, symmetry, and prototypicality, and trace their effects to changes in processing fluency. Other variables that influence processing fluency, like visual or semantic priming, similarly increase judgments of aesthetic pleasure. Our proposal provides an integrative framework for the study of aesthetic pleasure and sheds light on the interplay between early preferences versus cultural influences on taste, preferences for both prototypical and abstracted forms, and the relation between beauty and truth. In contrast to theories that trace aesthetic pleasure to objective stimulus features per se, we propose that beauty is grounded in the processing experiences of the perceiver, which are in part a function of stimulus properties.
TL;DR: A number of more recent algorithms that appear to work well with real-world network data, including algorithms based on edge betweenness scores, on counts of short loops in networks and on voltage differences in resistor networks are described.
Abstract: There has been considerable recent interest in algorithms for finding communities in networks— groups of vertices within which connections are dense, but between which connections are sparser. Here we review the progress that has been made towards this end. We begin by describing some traditional methods of community detection, such as spectral bisection, the Kernighan-Lin algorithm and hierarchical clustering based on similarity measures. None of these methods, however, is ideal for the types of real-world network data with which current research is concerned, such as Internet and web data and biological and social networks. We describe a number of more recent algorithms that appear to work well with these data, including algorithms based on edge betweenness scores, on counts of short loops in networks and on voltage differences in resistor networks.
Posted Content•
TL;DR: In this article, the authors investigate two key group-level determinants of virtual community participation -group norms and social identity -and consider their motivational antecedents and mediators.
Abstract: We investigate two key group-level determinants of virtual community participation - group norms and social identity - and consider their motivational antecedents and mediators. We also introduce a marketing-relevant typology to conceptualize virtual communities, based on the distinction between network-based, and small-group-based virtual communities. Our survey-based study, which was conducted across a broad range of virtual communities, supports the proposed model, and finds further that virtual community type moderates consumers' reasons for participating, as well as the strengths of their impact on group norms and social identity. We conclude with a consideration of managerial and research implications of the findings.