Showing papers by "University of Illinois at Urbana–Champaign published in 2003"
TL;DR: Fitness training was found to have robust but selective benefits for cognition, with the largest fitness-induced benefits occurring for executive-control processes.
Abstract: A meta-analytic study was conducted to examine the hypothesis that aerobic fitness training enhances the cognitive vitality of healthy but sedentary older adults. Eighteen intervention studies published between 1966 and 2001 were entered into the analysis. Several theoretically and practically important results were obtained. Most important fitness training was found to have robust but selective benefits for cognition, with the largest fitness-induced benefits occurring for executive-control processes. The magnitude of fitness effects on cognition was also moderated by a number of programmatic and methodological factors, including the length of the fitness-training intervention, the type of the intervention, the duration of training sessions, and the gender of the study participants. The results are discussed in terms of recent neuroscientific and psychological data that indicate cognitive and neural plasticity is maintained throughout the life span.
3,469 citations
TL;DR: Modification of the criteria for the diagnosis of restless legs syndrome is modified to better reflect that increased body of knowledge, as well as to clarify slight confusion with the wording of the original criteria.
2,834 citations
TL;DR: It is challenging to assess SWB across societies, the measures have some degree of cross-cultural validity and nations can be evaluated by their levels of SWB, there are still many open questions in this area.
Abstract: Subjective well-being (SWB), people's emotional and cognitive evaluations of their lives, includes what lay people call happiness, peace, fulfillment, and life satisfaction. Personality dispositions such as extraversion, neuroticism, and self-esteem can markedly influence levels of SWB. Although personality can explain a significant amount of the variability in SWB, life circumstances also influence long-term levels. Cultural variables explain differences in mean levels of SWB and appear to be due to objective factors such as wealth, to norms dictating appropriate feelings and how important SWB is considered to be, and to the relative approach versus avoidance tendencies of societies. Culture can also moderate which variables most influence SWB. Although it is challenging to assess SWB across societies, the measures have some degree of cross-cultural validity. Although nations can be evaluated by their levels of SWB, there are still many open questions in this area.
2,827 citations
TL;DR: For the multicast setup it is proved that there exist coding strategies that provide maximally robust networks and that do not require adaptation of the network interior to the failure pattern in question.
Abstract: We take a new look at the issue of network capacity. It is shown that network coding is an essential ingredient in achieving the capacity of a network. Building on recent work by Li et al.(see Proc. 2001 IEEE Int. Symp. Information Theory, p.102), who examined the network capacity of multicast networks, we extend the network coding framework to arbitrary networks and robust networking. For networks which are restricted to using linear network codes, we find necessary and sufficient conditions for the feasibility of any given set of connections over a given network. We also consider the problem of network recovery for nonergodic link failures. For the multicast setup we prove that there exist coding strategies that provide maximally robust networks and that do not require adaptation of the network interior to the failure pattern in question. The results are derived for both delay-free networks and networks with delays.
2,628 citations
TL;DR: In this paper, a theory of the opportunity identification process is proposed, which identifies entrepreneur's personality traits, social networks, and prior knowledge as antecedents of entrepreneurial alertness to business opportunities.
2,481 citations
TL;DR: This review attempts to present the still-incomplete understanding of how reactive oxygen species are formed inside cells and the mechanisms by which they damage specific target molecules.
Abstract: The phenomenon of oxygen toxicity is universal, but only recently have we begun to understand its basis in molecular terms. Redox enzymes are notoriously nonspecific, transferring electrons to any good acceptor with which they make electronic contact. This poses a problem for aerobic organisms, since molecular oxygen is small enough to penetrate all but the most shielded active sites of redox enzymes. Adventitious electron transfers to oxygen create superoxide and hydrogen peroxide, which are partially reduced species that can oxidize biomolecules with which oxygen itself reacts poorly. This review attempts to present our still-incomplete understanding of how reactive oxygen species are formed inside cells and the mechanisms by which they damage specific target molecules. The vulnerability of cells to oxidation lies at the root of obligate anaerobiosis, spontaneous mutagenesis, and the use of oxidative stress as a biological weapon.
2,023 citations
TL;DR: The results strongly support a hand-over-hand model of motility, not an inchworm model, which moves processively on actin.
Abstract: Myosin V is a dimeric molecular motor that moves processively on actin, with the center of mass moving 37 nanometers for each adenosine triphosphate hydrolyzed. We have labeled myosin V with a single fluorophore at different positions in the light-chain domain and measured the step size with a standard deviation of 1.5 nanometers, with 0.5-second temporal resolution, and observation times of minutes. The step size alternates between 37 2x nm and 37 – 2x, where x is the distance along the direction of motion between the dye and the midpoint between the two heads. These results strongly support a hand-over-hand model of motility, not an inchworm model. Myosin V is a cargo-carrying processive motor
1,888 citations
09 Sep 2003
TL;DR: A fundamentally different philosophy for data stream clustering is discussed which is guided by application-centered requirements and uses the concepts of a pyramidal time frame in conjunction with a microclustering approach.
Abstract: The clustering problem is a difficult problem for the data stream domain. This is because the large volumes of data arriving in a stream renders most traditional algorithms too inefficient. In recent years, a few one-pass clustering algorithms have been developed for the data stream problem. Although such methods address the scalability issues of the clustering problem, they are generally blind to the evolution of the data and do not address the following issues: (1) The quality of the clusters is poor when the data evolves considerably over time. (2) A data stream clustering algorithm requires much greater functionality in discovering and exploring clusters over different portions of the stream.
The widely used practice of viewing data stream clustering algorithms as a class of one-pass clustering algorithms is not very useful from an application point of view. For example, a simple one-pass clustering algorithm over an entire data stream of a few years is dominated by the outdated history of the stream. The exploration of the stream over different time windows can provide the users with a much deeper understanding of the evolving behavior of the clusters. At the same time, it is not possible to simultaneously perform dynamic clustering over all possible time horizons for a data stream of even moderately large volume.
This paper discusses a fundamentally different philosophy for data stream clustering which is guided by application-centered requirements. The idea is divide the clustering process into an online component which periodically stores detailed summary statistics and an offine component which uses only this summary statistics. The offine component is utilized by the analyst who can use a wide variety of inputs (such as time horizon or number of clusters) in order to provide a quick understanding of the broad clusters in the data stream. The problems of efficient choice, storage, and use of this statistical data for a fast data stream turns out to be quite tricky. For this purpose, we use the concepts of a pyramidal time frame in conjunction with a microclustering approach. Our performance experiments over a number of real and synthetic data sets illustrate the effectiveness, efficiency, and insights provided by our approach.
1,836 citations
TL;DR: The authors developed a theoretical model to describe and explain variation in corporate governance among advanced capitalist economies, identifying the social relations and institutional arrangements that shape who controls corporations, what interests corporations serve, and the allocation of rights and responsibilities among corporate stakeholders.
Abstract: We develop a theoretical model to describe and explain variation in corporate governance among advanced capitalist economies, identifying the social relations and institutional arrangements that shape who controls corporations, what interests corporations serve, and the allocation of rights and responsibilities among corporate stakeholders. Our “actor-centered” institutional approach explains firm-level corporate governance practices in terms of institutional factors that shape how actors' interests are defined (“socially constructed”) and represented. Our model has strong implications for studying issues of international convergence.
1,827 citations
Abstract: [1] An inventory of air pollutant emissions in Asia in the year 2000 is developed to support atmospheric modeling and analysis of observations taken during the TRACE-P experiment funded by the National Aeronautics and Space Administration (NASA) and the ACE-Asia experiment funded by the National Science Foundation (NSF) and the National Oceanic and Atmospheric Administration (NOAA). Emissions are estimated for all major anthropogenic sources, including biomass burning, in 64 regions of Asia. We estimate total Asian emissions as follows: 34.3 Tg SO2, 26.8 Tg NOx, 9870 Tg CO2, 279 Tg CO, 107 Tg CH4, 52.2 Tg NMVOC, 2.54 Tg black carbon (BC), 10.4 Tg organic carbon (OC), and 27.5 Tg NH3. In addition, NMVOC are speciated into 19 subcategories according to functional groups and reactivity. Thus we are able to identify the major source regions and types for many of the significant gaseous and particle emissions that influence pollutant concentrations in the vicinity of the TRACE-P and ACE-Asia field measurements. Emissions in China dominate the signature of pollutant concentrations in this region, so special emphasis has been placed on the development of emission estimates for China. China's emissions are determined to be as follows: 20.4 Tg SO2, 11.4 Tg NOx, 3820 Tg CO2, 116 Tg CO, 38.4 Tg CH4, 17.4 Tg NMVOC, 1.05 Tg BC, 3.4 Tg OC, and 13.6 Tg NH3. Emissions are gridded at a variety of spatial resolutions from 1° × 1° to 30 s × 30 s, using the exact locations of large point sources and surrogate GIS distributions of urban and rural population, road networks, landcover, ship lanes, etc. The gridded emission estimates have been used as inputs to atmospheric simulation models and have proven to be generally robust in comparison with field observations, though there is reason to think that emissions of CO and possibly BC may be underestimated. Monthly emission estimates for China are developed for each species to aid TRACE-P and ACE-Asia data interpretation. During the observation period of March/April, emissions are roughly at their average values (one twelfth of annual). Uncertainties in the emission estimates, measured as 95% confidence intervals, range from a low of ±16% for SO2 to a high of ±450% for OC.
1,816 citations
TL;DR: Reflexivity is commonly used in qualitative research and has been posited and accepted as a method qualitative researchers can and should use to legitimize, validate, and question research practices and representations.
Abstract: Reflexivity is commonly used in qualitative research and has been posited and accepted as a method qualitative researchers can and should use to legitimize, validate, and question research practices and representations. This paper closely examines the role of reflexivity as a methodological tool as it intersects with debates and questions surrounding representation and legitimization in qualitative research, within modernist and postmodernist ideologies, and pays close attention to how reflexivity is being defined and used in present-day research. Specifically, the author identifies and discusses the problematics of four common trends in present-day uses of reflexivity: reflexivity as recognition of self, reflexivity as recognition of other, reflexivity as truth, and reflexivity as transcendence. The author argues for a move away from comfortable uses of reflexivity to what she terms uncomfortable reflexive practices and provides an overview of the work of three authors who practice reflexivities of disco...
TL;DR: A qualitative study of motivation and barriers to employee participation in virtual knowledge‐sharing communities of practice at Caterpillar Inc., a Fortune 100, multinational corporation indicates that, when employees view knowledge as a public good belonging to the whole organization, knowledge flows easily.
Abstract: This paper reports the results of a qualitative study of motivation and barriers to employee participation in virtual knowledge‐sharing communities of practice at Caterpillar Inc., a Fortune 100, multinational corporation. The study indicates that, when employees view knowledge as a public good belonging to the whole organization, knowledge flows easily. However, even when individuals give the highest priority to the interests of the organization and of their community, they tend to shy away from contributing knowledge for a variety of reasons. Specifically, employees hesitate to contribute out of fear of criticism, or of misleading the community members (not being sure that their contributions are important, or completely accurate, or relevant to a specific discussion). To remove the identified barriers, there is a need for developing various types of trust, ranging from the knowledge‐based to the institution‐based trust. Future research directions and implications for KM practitioners are formulated.
TL;DR: A systematic search of the ssDNA library selected a sequence d(GT)n, n = 10 to 45 that self-assembles into a helical structure around individual nanotubes in such a way that the electrostatics of the DNA-CNT hybrid depends on tube diameter and electronic properties, enabling nanotube separation by anion exchange chromatography.
Abstract: Wrapping of carbon nanotubes (CNTs) by single-stranded DNA (ssDNA) was found to be sequence-dependent. A systematic search of the ssDNA library selected a sequence d(GT)n, n = 10 to 45 that self-assembles into a helical structure around individual nanotubes in such a way that the electrostatics of the DNA-CNT hybrid depends on tube diameter and electronic properties, enabling nanotube separation by anion exchange chromatography. Optical absorption and Raman spectroscopy show that early fractions are enriched in the smaller diameter and metallic tubes, whereas late fractions are enriched in the larger diameter and semiconducting tubes.
TL;DR: This review discusses combinatorial biological protocols, that is, bacterial cell surface and phage-display technologies, in the selection of short sequences that have affinity to (noble) metals, semiconducting oxides and other technological compounds.
Abstract: Proteins, through their unique and specific interactions with other macromolecules and inorganics, control structures and functions of all biological hard and soft tissues in organisms. Molecular biomimetics is an emerging field in which hybrid technologies are developed by using the tools of molecular biology and nanotechnology. Taking lessons from biology, polypeptides can now be genetically engineered to specifically bind to selected inorganic compounds for applications in nano- and biotechnology. This review discusses combinatorial biological protocols, that is, bacterial cell surface and phage-display technologies, in the selection of short sequences that have affinity to (noble) metals, semiconducting oxides and other technological compounds. These genetically engineered proteins for inorganics (GEPIs) can be used in the assembly of functional nanostructures. Based on the three fundamental principles of molecular recognition, self-assembly and DNA manipulation, we highlight successful uses of GEPI in nanotechnology.
TL;DR: In this paper, the authors review the present understanding of film growth processes and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.
Abstract: Atomic-scale control and manipulation of the microstructure of polycrystalline thin films during kinetically limited low-temperature deposition, crucial for a broad range of industrial applications, has been a leading goal of materials science during the past decades. Here, we review the present understanding of film growth processes—nucleation, coalescence, competitive grain growth, and recrystallization—and their role in microstructural evolution as a function of deposition variables including temperature, the presence of reactive species, and the use of low-energy ion irradiation during growth.
TL;DR: This model constructs a price-setting game between a manufacturer and its independent retailer and shows that the mere threat of introducing the direct channel can increase the manufacturer's negotiated share of cooperative profits even if price efficiency is obtained by using other business practices.
Abstract: The advent of e-commerce has prompted many manufacturers to redesign their traditional channel structures by engaging in direct sales. The model conceptualizes the impact of customer acceptance of a direct channel, the degree to which customers accept a direct channel as a substitute for shopping at a traditional store, on supply-chain design. The customer acceptance of a direct channel can be strong enough that an indepent manufacturer would open a direct channel to compete with its own retailers. Here, direct marketing is used for strategic channel control purposes even though it is inefficient on its own and, surprisingly, it can profit the manufacturer even when so direct sales occur. Specifically, we construct a price-setting game between a manufacturer and its independent retailer. Direct marketing, which indirectly increases the flow of profits through the retail channel, helps the manufacturer improve overall profitability by reducing the degree of inefficient price double marginalization. While operated by the manufacturer to constrain the retailer's pricing behavior, the direct channel may not always be detrimental to the retailer because it will be accompanied by a wholesale price reduction. This combination of manufacturer pull and push can benefit the retailer in equilibrium. Finally, we show that the mere threat of introducing the direct channel can increase the manufacturer's negotiated share of cooperative profits even if price efficiency is obtained by using other business practices.
Shimane University1, University of Freiburg2, University of Manitoba3, University of Kentucky4, University of Marburg5, St. Michael's Hospital6, Baylor College of Medicine7, University of Illinois at Urbana–Champaign8, Scripps Health9, Oregon Health & Science University10, Tulane University11, Mayo Clinic12, Michigan State University13, University of Göttingen14, Max Planck Society15, University of California, Los Angeles16, Rutgers University17, Seton Hall University18
TL;DR: This scale meets performance criteria for a brief, patient completed instrument that can be used to assess RLS severity for purposes of clinical assessment, research, or therapeutic trials and supports a finding that RLS is a relatively uniform disorder in which the severity of the basic symptoms is strongly related to their impact on the patient's life.
TL;DR: In this paper, the authors document evidence on the relation between auditor tenure and earnings quality using the dispersion and sign of both absolute Jones model abnormal accruals and absolute current accrual.
Abstract: In this study, we document evidence on the relation between auditor tenure and earnings quality using the dispersion and sign of both absolute Jones‐model abnormal accruals and absolute current acc...
24 Aug 2003
TL;DR: This paper proposes a general framework for mining concept-drifting data streams using weighted ensemble classifiers, and shows that the proposed methods have substantial advantage over single-classifier approaches in prediction accuracy, and the ensemble framework is effective for a variety of classification models.
Abstract: Recently, mining data streams with concept drifts for actionable insights has become an important and challenging task for a wide range of applications including credit card fraud protection, target marketing, network intrusion detection, etc. Conventional knowledge discovery tools are facing two challenges, the overwhelming volume of the streaming data, and the concept drifts. In this paper, we propose a general framework for mining concept-drifting data streams using weighted ensemble classifiers. We train an ensemble of classification models, such as C4.5, RIPPER, naive Beyesian, etc., from sequential chunks of the data stream. The classifiers in the ensemble are judiciously weighted based on their expected classification accuracy on the test data under the time-evolving environment. Thus, the ensemble approach improves both the efficiency in learning the model and the accuracy in performing classification. Our empirical study shows that the proposed methods have substantial advantage over single-classifier approaches in prediction accuracy, and the ensemble framework is effective for a variety of classification models.
TL;DR: In this article, the authors estimate economic losses sustained by major US livestock industries from heat stress, including decreased performance (feed intake, growth, milk, eggs), increased mortality, and decreased reproduction.
TL;DR: The sum capacity of the vector Gaussian broadcast channel is characterized by showing that the existing inner bound of Marton and the existing upper bound of Sato are tight for this channel.
Abstract: We characterize the sum capacity of the vector Gaussian broadcast channel by showing that the existing inner bound of Marton and the existing upper bound of Sato are tight for this channel. We exploit an intimate four-way connection between the vector broadcast channel, the corresponding point-to-point channel (where the receivers can cooperate), the multiple-access channel (MAC) (where the role of transmitters and receivers are reversed), and the corresponding point-to-point channel (where the transmitters can cooperate).
TL;DR: Diazonium reagents functionalize single-walled carbon nanotubes suspended in aqueous solution with high selectivity and enable manipulation according to electronic structure to reverse the chemistry by using a thermal treatment that restores the pristine electronic structure of the nanotube.
Abstract: Diazonium reagents functionalize single-walled carbon nanotubes suspended in aqueous solution with high selectivity and enable manipulation according to electronic structure. For example, metallic species are shown to react to the near exclusion of semiconducting nanotubes under controlled conditions. Selectivity is dictated by the availability of electrons near the Fermi level to stabilize a charge-transfer transition state preceding bond formation. The chemistry can be reversed by using a thermal treatment that restores the pristine electronic structure of the nanotube.
TL;DR: The concept developed here can be applied to the design of nucleic acid enzyme/nanoparticle sensors for analytes that are subject to in vitro selection, and thus can significantly expand the scope of nanomaterial applications and provide a novel approach to designing simple colorimetric biosensors.
Abstract: A highly sensitive and selective colorimetric lead biosensor based on DNAzyme-directed assembly of gold nanoparticles is reported. It consists of a DNAzyme and its substrate that can hybridize to a 5‘-thio-modified DNA attached to gold nanoparticles. The hybridization brings gold nanoparticles together, resulting in a blue-colored nanoparticle assembly. In the presence of lead, the DNAzyme catalyzes specific hydrolytic cleavage, which prevents the formation of the nanoparticle assembly, resulting in red-colored individual nanoparticles. The detection level can be tuned to several orders of magnitude, from 100 nM to over 200 μM, through addition of an inactive variant of the DNAzyme. The concept developed here can be applied to the design of nucleic acid enzyme/nanoparticle sensors for analytes that are subject to in vitro selection, and thus can significantly expand the scope of nanomaterial applications and provide a novel approach to designing simple colorimetric biosensors.
TL;DR: The authors proposed that emotional exhaustion would predict job performance, 2 classes of organizational citizenship behavior, and turnover intentions and posited that the relationship between emotional exhaustion and effective work behaviors would be mediated by organizational commitment.
Abstract: The authors investigated the negative consequences of emotional exhaustion for individual employees and their employers. On the basis of social exchange theory, the authors proposed that emotional exhaustion would predict job performance, 2 classes of organizational citizenship behavior, and turnover intentions. In addition, the authors posited that the relationship between emotional exhaustion and effective work behaviors would be mediated by organizational commitment. With only a few exceptions, the results of 2 field studies supported the authors' expectations. In addition, emotional exhaustion exerted an independent effect on these criterion variables beyond the impact of age, gender, and ethnicity.
TL;DR: Resistance to silver compounds as determined by bacterial plasmids and genes has been defined by molecular genetics and the use of molecular epidemiological tools will establish the range and diversity of such resistance systems in clinical and non-clinical sources.
Abstract: Resistance to silver compounds as determined by bacterial plasmids and genes has been defined by molecular genetics. Silver resistance conferred by the Salmonella plasmid pMGH100 involves nine genes in three transcription units. A sensor/responder (SilRS) two-component transcriptional regulatory system governs synthesis of a periplasmic Ag(I)-binding protein (SilE) and two efflux pumps (a P-type ATPase (SilP) plus a three-protein chemiosmotic RND Ag(I)/H+ exchange system (SilCBA)). The same genes were identified on five of 19 additional IncH incompatibility class plasmids but thus far not on other plasmids. Of 70 random enteric isolates from a local hospital, isolates from catheters and other Ag-exposed sites, and total genomes of enteric bacteria, 10 have recognizable sil genes. The centrally located six genes are found and functional in the chromosome of Escherichia coli K-12, and also occur on the genome of E. coli O157:H7. The use of molecular epidemiological tools will establish the range and diversity of such resistance systems in clinical and non-clinical sources. Silver compounds are used widely as effective antimicrobial agents to combat pathogens (bacteria, viruses and eukaryotic microorganisms) in the clinic and for public health hygiene. Silver cations (Ag+) are microcidal at low concentrations and used to treat burns, wounds and ulcers. Ag is used to coat catheters to retard microbial biofilm development. Ag is used in hygiene products including face creams, ‘alternative medicine’ health supplements, supermarket products for washing vegetables, and water filtration cartridges. Ag is generally without adverse effects for humans, and argyria (irreversible discoloration of the skin resulting from subepithelial silver deposits) is rare and mostly of cosmetic concern.
TL;DR: Sixty-three studies published in the years 1997-2002 are reviewed to assess the effects of workplace diversity on teams and organizations as discussed by the authors, and the strengths and weaknesses of recent diversity research, point out opportunities for new research, and identify threats to continued advancement.
TL;DR: Data from a 15-year longitudinal study of over 24.000 individuals was used to examine the effects of marital transitions on life satisfaction and found individuals reacted to events and then adapted back toward baseline levels, but there were substantial individual differences in this tendency.
Abstract: According to adaptation theory, individuals react to events but quickly adapt back to baseline levels of subjective well-being. To test this idea, the authors used data from a 15-year longitudinal study of over 24.000 individuals to examine the effects of marital transitions on life satisfaction. On average, individuals reacted to events and then adapted back toward baseline levels. However, there were substantial individual differences in this tendency. Individuals who initially reacted strongly were still far from baseline years later, and many people exhibited trajectories that were in the opposite direction to that predicted by adaptation theory. Thus, marital transitions can be associated with long-lasting changes in satisfaction, but these changes can be overlooked when only average trends are examined.
TL;DR: In this article, a special issue on bullying and victimization in school psychology review highlights current research efforts in American schools on bullying, peer victimization, and how this research can in
Abstract: This special issue on bullying and victimization in School Psychology Review highlights current research efforts in American schools on bullying and peer victimization, and how this research can in
TL;DR: In this paper, the authors review the recent and rapid developments in semi-active structural control and its implementation in full-scale structures, and present an alternative to active and hybrid control for structural vibration reduction.
Abstract: In recent years, considerable attention has been paid to research and development of structural control devices, with particular emphasis on alleviation of wind and seismic response of buildings and bridges. In both areas, serious efforts have been undertaken in the last two decades to develop the structural control concept into a workable technology. Full-scale implementation of active control systems have been accomplished in several structures, mainly in Japan; however, cost effectiveness and reliability considerations have limited their wide spread acceptance. Because of their mechanical simplicity, low power requirements, and large, controllable force capacity, semiactive systems provide an attractive alternative to active and hybrid control systems for structural vibration reduction. In this paper we review the recent and rapid developments in semiactive structural control and its implementation in full-scale structures.
TL;DR: In this paper, the authors compare and contrast the advantages of two limiting perspectives on the high-temperature superconductor: weak coupling, in which correlation effects are treated as a perturbation on an underlying metallic (although renormalized) Fermi-liquid state, and strong coupling, where the magnetism is associated with well defined localized spins, and stripes are viewed as a form of micro phase separation.
Abstract: This article discusses fluctuating order in a quantum disordered phase proximate to a quantum critical point, with particular emphasis on fluctuating stripe order. Optimal strategies are derived for extracting information concerning such local order from experiments, with emphasis on neutron scattering and scanning tunneling microscopy. These ideas are tested by application to two model systems---an exactly solvable one-dimensional (1D) electron gas with an impurity, and a weakly interacting 2D electron gas. Experiments on the cuprate high-temperature superconductors which can be analyzed using these strategies are extensively reviewed. The authors adduce evidence that stripe correlations are widespread in the cuprates. They compare and contrast the advantages of two limiting perspectives on the high-temperature superconductor: weak coupling, in which correlation effects are treated as a perturbation on an underlying metallic (although renormalized) Fermi-liquid state, and strong coupling, in which the magnetism is associated with well-defined localized spins, and stripes are viewed as a form of micro phase separation. The authors present quantitative indicators that the latter view better accounts for the observed stripe phenomena in the cuprates.