Showing papers by "University of Southern California published in 2002"

Social Capital: Prospects for a New Concept

Abstract: A growing number of sociologists, political scientists, economists, and organizational theorists have invoked the concept of social capital in the search for answers to a broadening range of questions being confronted in their own fields. Seeking to clarify the concept and help assess its utility for organizational theory, we synthesize the theoretical research undertaken in these various disciplines and develop a common conceptual framework that identifies the sources, benefits, risks, and contingencies of social capital.

The fundamental role of epigenetic events in cancer

Abstract: Patterns of DNA methylation and chromatin structure are profoundly altered in neoplasia and include genome-wide losses of, and regional gains in, DNA methylation. The recent explosion in our knowledge of how chromatin organization modulates gene transcription has further highlighted the importance of epigenetic mechanisms in the initiation and progression of human cancer. These epigenetic changes -- in particular, aberrant promoter hypermethylation that is associated with inappropriate gene silencing -- affect virtually every step in tumour progression. In this review, we discuss these epigenetic events and the molecular alterations that might cause them and/or underlie altered gene expression in cancer.

An energy-efficient MAC protocol for wireless sensor networks

Abstract: This paper proposes S-MAC, a medium-access control (MAC) protocol designed for wireless sensor networks Wireless sensor networks use battery-operated computing and sensing devices A network of these devices will collaborate for a common application such as environmental monitoring We expect sensor networks to be deployed in an ad hoc fashion, with individual nodes remaining largely inactive for long periods of time, but then becoming suddenly active when something is detected These characteristics of sensor networks and applications motivate a MAC that is different from traditional wireless MACs such as IEEE 80211 in almost every way: energy conservation and self-configuration are primary goals, while per-node fairness and latency are less important S-MAC uses three novel techniques to reduce energy consumption and support self-configuration To reduce energy consumption in listening to an idle channel, nodes periodically sleep Neighboring nodes form virtual clusters to auto-synchronize on sleep schedules Inspired by PAMAS, S-MAC also sets the radio to sleep during transmissions of other nodes Unlike PAMAS, it only uses in-channel signaling Finally, S-MAC applies message passing to reduce contention latency for sensor-network applications that require store-and-forward processing as data move through the network We evaluate our implementation of S-MAC over a sample sensor node, the Mote, developed at University of California, Berkeley The experiment results show that, on a source node, an 80211-like MAC consumes 2-6 times more energy than S-MAC for traffic load with messages sent every 1-10 s

Serum TSH, T4, and Thyroid Antibodies in the United States Population (1988 to 1994): National Health and Nutrition Examination Survey (NHANES III)

Abstract: NHANES III measured serum TSH, total serum T(4), antithyroperoxidase (TPOAb), and antithyroglobulin (TgAb) antibodies from a sample of 17,353 people aged > or =12 yr representing the geographic and ethnic distribution of the U.S. population. These data provide a reference for other studies of these analytes in the U.S. For the 16,533 people who did not report thyroid disease, goiter, or taking thyroid medications (disease-free population), we determined mean concentrations of TSH, T(4), TgAb, and TPOAb. A reference population of 13,344 people was selected from the disease-free population by excluding, in addition, those who were pregnant, taking androgens or estrogens, who had thyroid antibodies, or biochemical hypothyroidism or hyperthyroidism. The influence of demographics on TSH, T(4), and antibodies was examined. Hypothyroidism was found in 4.6% of the U.S. population (0.3% clinical and 4.3% subclinical) and hyperthyroidism in 1.3% (0.5% clinical and 0.7% subclinical). (Subclinical hypothyroidism is used in this paper to mean mild hypothyroidism, the term now preferred by the American Thyroid Association for the laboratory findings described.) For the disease-free population, mean serum TSH was 1.50 (95% confidence interval, 1.46-1.54) mIU/liter, was higher in females than males, and higher in white non-Hispanics (whites) [1.57 (1.52-1.62) mIU/liter] than black non-Hispanics (blacks) [1.18 (1.14-1.21) mIU/liter] (P < 0.001) or Mexican Americans [1.43 (1.40-1.46) mIU/liter] (P < 0.001). TgAb were positive in 10.4 +/- 0.5% and TPOAb, in 11.3 +/- 0.4%; positive antibodies were more prevalent in women than men, increased with age, and TPOAb were less prevalent in blacks (4.5 +/- 0.3%) than in whites (12.3 +/- 0.5%) (P < 0.001). TPOAb were significantly associated with hypo or hyperthyroidism, but TgAb were not. Using the reference population, geometric mean TSH was 1.40 +/- 0.02 mIU/liter and increased with age, and was significantly lower in blacks (1.18 +/- 0.02 mIU/liter) than whites (1.45 +/- 0.02 mIU/liter) (P < 0.001) and Mexican Americans (1.37 +/- 0.02 mIU/liter) (P < 0.001). Arithmetic mean total T(4) was 112.3 +/- 0.7 nmol/liter in the disease-free population and was consistently higher among Mexican Americans in all populations. In the reference population, mean total T(4) in Mexican Americans was (116.3 +/- 0.7 nmol/liter), significantly higher than whites (110.0 +/- 0.8 nmol/liter) or blacks (109.4 +/- 0.8 nmol/liter) (P < 0.0001). The difference persisted in all age groups. In summary, TSH and the prevalence of antithyroid antibodies are greater in females, increase with age, and are greater in whites and Mexican Americans than in blacks. TgAb alone in the absence of TPOAb is not significantly associated with thyroid disease. The lower prevalence of thyroid antibodies and lower TSH concentrations in blacks need more research to relate these findings to clinical status. A large proportion of the U.S. population unknowingly have laboratory evidence of thyroid disease, which supports the usefulness of screening for early detection.

Genetic Structure of Human Populations

Abstract: We studied human population structure using genotypes at 377 autosomal microsatellite loci in 1056 individuals from 52 populations. Within-population differences among individuals account for 93 to 95% of genetic variation; differences among major groups constitute only 3 to 5%. Nevertheless, without using prior information about the origins of individuals, we identified six main genetic clusters, five of which correspond to major geographic regions, and subclusters that often correspond to individual populations. General agreement of genetic and predefined populations suggests that self-reported ancestry can facilitate assessments of epidemiological risks but does not obviate the need to use genetic information in genetic association studies.

Type-2 fuzzy sets made simple

Abstract: Type-2 fuzzy sets let us model and minimize the effects of uncertainties in rule-base fuzzy logic systems. However, they are difficult to understand for a variety of reasons which we enunciate. In this paper, we strive to overcome the difficulties by: (1) establishing a small set of terms that let us easily communicate about type-2 fuzzy sets and also let us define such sets very precisely, (2) presenting a new representation for type-2 fuzzy sets, and (3) using this new representation to derive formulas for union, intersection and complement of type-2 fuzzy sets without having to use the Extension Principle.

A Thermally Re-mendable Cross-Linked Polymeric Material

Abstract: We have developed a transparent organic polymeric material that can repeatedly mend or "re-mend" itself under mild conditions. The material is a tough solid at room temperature and below with mechanical properties equaling those of commercial epoxy resins. At temperatures above 120 degrees C, approximately 30% (as determined by solid-state nuclear magnetic resonance spectroscopy) of "intermonomer" linkages disconnect but then reconnect upon cooling, This process is fully reversible and can be used to restore a fractured part of the polymer multiple times, and it does not require additional ingredients such as a catalyst, additional monomer, or special surface treatment of the fractured interface.

Ultrafine particulate pollutants induce oxidative stress and mitochondrial damage.

Abstract: The objectives of this study were to determine whether differences in the size and composition of coarse (2.5-10 micro m), fine (< 2.5 microm), and ultrafine (< 0.1 microm) particulate matter (PM) are related to their uptake in macrophages and epithelial cells and their ability to induce oxidative stress. The premise for this study is the increasing awareness that various PM components induce pulmonary inflammation through the generation of oxidative stress. Coarse, fine, and ultrafine particles (UFPs) were collected by ambient particle concentrators in the Los Angeles basin in California and used to study their chemical composition in parallel with assays for generation of reactive oxygen species (ROS) and ability to induce oxidative stress in macrophages and epithelial cells. UFPs were most potent toward inducing cellular heme oxygenase-1 (HO-1) expression and depleting intracellular glutathione. HO-1 expression, a sensitive marker for oxidative stress, is directly correlated with the high organic carbon and polycyclic aromatic hydrocarbon (PAH) content of UFPs. The dithiothreitol (DTT) assay, a quantitative measure of in vitro ROS formation, was correlated with PAH content and HO-1 expression. UFPs also had the highest ROS activity in the DTT assay. Because the small size of UFPs allows better tissue penetration, we used electron microscopy to study subcellular localization. UFPs and, to a lesser extent, fine particles, localize in mitochondria, where they induce major structural damage. This may contribute to oxidative stress. Our studies demonstrate that the increased biological potency of UFPs is related to the content of redox cycling organic chemicals and their ability to damage mitochondria.

Evidence of the effect of trust building technology in electronic markets: price premiums and buyer behavior

Abstract: Despite the wide use of reputational mechanisms such as eBay's Feedback Forum to promote trust, empirical studies have shown conflicting results as to whether online feedback mechanisms induce trust and lead to higher auction prices. This study examines the extent to which trust can be induced by proper feedback mechanisms in electronic markets, and how some risk factors play a role in trust formation. Drawing from economic, sociological, and marketing theories and using data from both an online experiment and an online auction market, we demonstrate that appropriate feedback mechanisms can induce calculus-based credibility trust without repeated interactions between two transacting parties. Trust can mitigate information asymmetry by reducing transaction-specific risks, therefore generating price premiums for reputable sellers. In addition, the research also examines the role that trust plays in mitigating the risks inherent in transactions that involve very expensive products.

Grid services for distributed system integration

Abstract: Increasingly, computing addresses collaboration, data sharing, and interaction modes that involve distributed resources, resulting in an increased focus on the interconnection of systems both within and across enterprises. These evolutionary pressures have led to the development of Grid technologies. The authors' work focuses on the nature of the services that respond to protocol messages. Grid provides an extensible set of services that can be aggregated in various ways to meet the needs of virtual organizations, which themselves can be defined in part by the services they operate and share.

Comprehensive analysis of CpG islands in human chromosomes 21 and 22

Abstract: CpG islands are useful markers for genes in organisms containing 5-methylcytosine in their genomes. In addition, CpG islands located in the promoter regions of genes can play important roles in gene silencing during processes such as X-chromosome inactivation, imprinting, and silencing of intragenomic parasites. The generally accepted definition of what constitutes a CpG island was proposed in 1987 by Gardiner-Garden and Frommer [Gardiner-Garden, M. & Frommer, M. (1987) J. Mol. Biol. 196, 261–282] as being a 200-bp stretch of DNA with a C+G content of 50% and an observed CpG/expected CpG in excess of 0.6. Any definition of a CpG island is somewhat arbitrary, and this one, which was derived before the sequencing of mammalian genomes, will include many sequences that are not necessarily associated with controlling regions of genes but rather are associated with intragenomic parasites. We have therefore used the complete genomic sequences of human chromosomes 21 and 22 to examine the properties of CpG islands in different sequence classes by using a search algorithm that we have developed. Regions of DNA of greater than 500 bp with a G+C equal to or greater than 55% and observed CpG/expected CpG of 0.65 were more likely to be associated with the 5′ regions of genes and this definition excluded most Alu-repetitive elements. We also used genome sequences to show strong CpG suppression in the human genome and slight suppression in Drosophila melanogaster and Saccharomyces cerevisiae. This finding is compatible with the recent detection of 5-methylcytosine in Drosophila, and might suggest that S. cerevisiae has, or once had, CpG methylation.

Relational Contracts and the Theory of the Firm

Abstract: Relational contracts—informal agreements sustained by the value of future relationships—are prevalent within and between firms. We develop repeated-game models showing why and how relational contracts within firms (vertical integration) differ from those between (nonintegration). We show that integration affects the parties' temptations to renege on a given relational contract, and hence affects the best relational contract the parties can sustain. In this sense, the integration decision can be an instrument in the service of the parties' relationship. Our approach also has implications for joint ventures, alliances, and networks, and for the role of management within and between firms.

Preservation of Pancreatic Beta-Cell Function and Prevention of Type 2 Diabetes by Pharmacological Treatment of Insulin Resistance in High-Risk Hispanic Women

Abstract: Type 2 diabetes frequently results from progressive failure of pancreatic beta-cell function in the presence of chronic insulin resistance. We tested whether chronic amelioration of insulin resistance would preserve pancreatic beta-cell function and delay or prevent the onset of type 2 diabetes in high-risk Hispanic women. Women with previous gestational diabetes were randomized to placebo (n = 133) or the insulin-sensitizing drug troglitazone (400 mg/day; n = 133) administered in double-blind fashion. Fasting plasma glucose was measured every 3 months, and oral glucose tolerance tests (OGTTs) were performed annually to detect diabetes. Intravenous glucose tolerance tests (IVGTTs) were performed at baseline and 3 months later to identify early metabolic changes associated with any protection from diabetes. Women who did not develop diabetes during the trial returned for OGTTs and IVGTTs 8 months after study medications were stopped. During a median follow-up of 30 months on blinded medication, average annual diabetes incidence rates in the 236 women who returned for at least one follow-up visit were 12.1 and 5.4% in women assigned to placebo and troglitazone, respectively (P < 0.01). Protection from diabetes in the troglitazone group 1) was closely related to the degree of reduction in endogenous insulin requirements 3 months after randomization, 2) persisted 8 months after study medications were stopped, and 3) was associated with preservation of beta-cell compensation for insulin resistance. Treatment with troglitazone delayed or prevented the onset of type 2 diabetes in high-risk Hispanic women. The protective effect was associated with the preservation of pancreatic beta-cell function and appeared to be mediated by a reduction in the secretory demands placed on beta-cells by chronic insulin resistance.

Mobile Sensor Network Deployment using Potential Fields: A Distributed, Scalable Solution to the Area Coverage Problem

Abstract: This paper considers the problem of deploying a mobile sensor network in an unknown environment. A mobile sensor network is composed of a distributed collection of nodes, each of which has sensing, computation, communication and locomotion capabilities. Such networks are capable of self-deployment; i.e., starting from some compact initial configuration, the nodes in the network can spread out such that the area ‘covered’ by the network is maximized. In this paper, we present a potential-field-based approach to deployment. The fields are constructed such that each node is repelled by both obstacles and by other nodes, thereby forcing the network to spread itself throughout the environment. The approach is both distributed and scalable.

Motion graphs

Abstract: In this paper we present a novel method for creating realistic, controllable motion. Given a corpus of motion capture data, we automatically construct a directed graph called a motion graph that encapsulates connections among the database. The motion graph consists both of pieces of original motion and automatically generated transitions. Motion can be generated simply by building walks on the graph. We present a general framework for extracting particular graph walks that meet a user's specifications. We then show how this framework can be applied to the specific problem of generating different styles of locomotion along arbitrary paths.

The PedsQL in pediatric cancer: reliability and validity of the Pediatric Quality of Life Inventory Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module.

Abstract: BACKGROUND The Pediatric Quality of Life Inventory (PedsQL) is a modular instrument designed to measure health-related quality of life (HRQOL) in children and adolescents ages 2–18 years. The PedsQL 4.0 Generic Core Scales are multidimensional child self-report and parent proxy-report scales developed as the generic core measure to be integrated with the PedsQL disease specific modules. The PedsQL Multidimensional Fatigue Scale was designed to measure fatigue in pediatric patients. The PedsQL 3.0 Cancer Module was designed to measure pediatric cancer specific HRQOL. METHODS The PedsQL Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module were administered to 339 families (220 child self-reports; 337 parent proxy-reports). RESULTS Internal consistency reliability for the PedsQL Generic Core Total Scale Score (α = 0.88 child, 0.93 parent report), Multidimensional Fatigue Total Scale Score (α = 0.89 child, 0.92 parent report) and most Cancer Module Scales (average α = 0.72 child, 0.87 parent report) demonstrated reliability acceptable for group comparisons. Validity was demonstrated using the known-groups method. The PedsQL distinguished between healthy children and children with cancer as a group, and among children on-treatment versus off-treatment. The validity of the PedsQL Multidimensional Fatigue Scale was further demonstrated through hypothesized intercorrelations with dimensions of generic and cancer specific HRQOL. CONCLUSIONS The results demonstrate the reliability and validity of the PedsQL Generic Core Scales, Multidimensional Fatigue Scale, and Cancer Module in pediatric cancer. The PedsQL may be utilized as an outcome measure in clinical trials, research, and clinical practice. Cancer 2002;94:2090–106. © 2002 American Cancer Society. DOI 10.1002/cncr.10427

A design theory for systems that support emergent knowledge processes

Abstract: This paper addresses the design problem of providing IT support for emerging knowledge processes (EKPs). EKPs are organizational activity patterns that exhibit three characteristics in combination: an emergent process of deliberations with no best structure or sequence; requirements for knowledge that are complex (both general and situational), distributed across people, and evolving dynamically; and an actor set that is unpredictable in terms of job roles or prior knowledge. Examples of EKPs include basic research, new product development, strategic business planning, and organization design. EKPs differ qualitatively from semi-structured decision making processes; therefore, they have unique requirements that are not all thoroughly supported by familiar classes of systems, such as executive information systems, expert systems, electronic communication systems, organizational memory systems, or repositories. Further, the development literature on familiar classes of systems does not provide adequate guidance on how to build systems that support EKPs. Consequently, EKPs require a new IS design theory, as explicated by Walls et al. (1992). We created such a theory while designing and deploying a system for the EKP of organization design. The system was demonstrated through subsequent empirical analysis to be successful in supporting the process. Abstracting from the experience of building this system, we developed an IS design theory for EKP support systems. This new IS design theory is an important theoretical contribution, because it both provides guidance to developers and sets an agenda for academic research. EKP design theory makes the development process more tractable for developers by restricting the range of effective features (or rules for selecting features) and the range of effective development practices to a more manageable set. EKP design theory also sets an agenda for academic research by articulating theory-based principles that are subject to empirical, as well as practical, validation.

Data gathering algorithms in sensor networks using energy metrics

Abstract: Gathering sensed information in an energy efficient manner is critical to operating the sensor network for a long period of time. The LEACH protocol presented by Heinzelman et al. (2000) is an elegant solution where clusters are formed to fuse data before transmitting to the base station. In this paper, we present an improved scheme, called PEGASIS (power-efficient gathering in sensor information systems), which is a near-optimal chain-based protocol that minimizes energy. In PEGASIS, each node communicates only with a close neighbor and takes turns transmitting to the base station, thus reducing the amount of energy spent per round. Simulation results show that PEGASIS performs better than LEACH. For many applications, in addition to minimizing energy, it is also important to consider the delay incurred in gathering sensed data. We capture this with the energy /spl times/ delay metric and present schemes that attempt to balance the energy and delay cost for data gathering from sensor networks. We present two new schemes to minimize energy /spl times/ delay using CDMA and non-CDMA sensor nodes. We compared the performance of direct, LEACH, and our schemes with respect to energy /spl times/ delay using extensive simulations for different network sizes. Results show that our schemes perform 80 or more times better than the direct scheme and also outperform the LEACH protocol.

Do Non-audit Service Fees Impair Auditor Independence? Evidence from Going-concern Audit Opinions

Abstract: We find no evidence that non-audit service fees impair auditor independence, where independence is surrogated by auditors' propensity to issue going concern audit opinions. We do find, however, that auditors are more likely to issue going concern opinions to clients paying higher audit fees, suggesting that auditors behave with relatively greater independence towards these clients. Our findings are consistent with Reynolds and Francis (2001) and suggest that market-based incentives, such as loss of reputation and litigation costs, dominate the benefits auditors are likely to receive from compromising their independence to retain clients that pay larger fees. Overall, our findings indicate that recent SEC regulations based on concerns that non-audit services impair auditor independence, are unfounded.

Sold!: auction methods for multirobot coordination

Abstract: The key to utilizing the potential of multirobot systems is cooperation. How can we achieve cooperation in systems composed of failure-prone autonomous robots operating in noisy, dynamic environments? We present a method of dynamic task allocation for groups of such robots. We implemented and tested an auction-based task allocation system which we call MURDOCH, built upon a principled, resource centric, publish/subscribe communication model. A variant of the Contract Net Protocol, MURDOCH produces a distributed approximation to a global optimum of resource usage. We validated MURDOCH in two very different domains: a tightly coupled multirobot physical manipulation task and a loosely coupled multirobot experiment in long-term autonomy. The primary contribution of the paper is to show empirically that distributed negotiation mechanisms such as MURDOCH are viable and effective for coordinating physical multirobot systems.

Conceptualizing and Measuring Democracy. Evaluating Alternative Indices

Abstract: A comprehensive and integrated framework for the analysis of data is offered and used to assess data sets on democracy. The framework first distinguishes among three challenges that are sequentially addressed: conceptualization, measurement, and aggregation. In turn, it specifies distinct tasks associated with these challenges and the standards of assessment that pertain to each task. This framework is applied to the data sets on democracy most frequently used in current statistical research, generating a systematic evaluation of these data sets. The authors’ conclusion is that constructors of democracy indices tend to be quite self-conscious about methodological issues but that even the best indices suffer from important weaknesses. More constructively, the article’s assessment of existing data sets on democracy identifies distinct areas in which attempts to improve the quality of data on democracy might fruitfully be focused.

Concentration and Size Distribution of Ultrafine Particles Near a Major Highway

Abstract: Motor vehicle emissions usually constitute the most significant source of ultrafine particles (diameter <0.1 microm) in an urban environment, yet little is known about the concentration and size distribution of ultrafine particles in the vicinity of major highways. In the present study, particle number concentration and size distribution in the size range from 6 to 220 nm were measured by a condensation particle counter (CPC) and a scanning mobility particle sizer (SMPS), respectively. Measurements were taken 30, 60, 90, 150, and 300 m downwind, and 300 m upwind, from Interstate 405 at the Los Angeles National Cemetery. At each sampling location, concentrations of CO, black carbon (BC), and particle mass were also measured by a Dasibi CO monitor, an aethalometer, and a DataRam, respectively. The range of average concentration of CO, BC, total particle number, and mass concentration at 30 m was 1.7-2.2 ppm, 3.4-10.0 microg/m3, 1.3-2.0 x 10(5)/cm3, and 30.2-64.6 microg/m3, respectively. For the conditions of these measurements, relative concentrations of CO, BC, and particle number tracked each other well as distance from the freeway increased. Particle number concentration (6-220 nm) decreased exponentially with downwind distance from the freeway. Data showed that both atmospheric dispersion and coagulation contributed to the rapid decrease in particle number concentration and change in particle size distribution with increasing distance from the freeway. Average traffic flow during the sampling periods was 13,900 vehicles/hr. Ninety-three percent of vehicles were gasoline-powered cars or light trucks. The measured number concentration tracked traffic flow well. Thirty meters downwind from the freeway, three distinct ultrafine modes were observed with geometric mean diameters of 13, 27, and 65 nm. The smallest mode, with a peak concentration of 1.6 x 10(5)/cm3, disappeared at distances greater than 90 m from the freeway. Ultrafine particle number concentration measured 300 m downwind from the freeway was indistinguishable from upwind background concentration. These data may be used to estimate exposure to ultrafine particles in the vicinity of major highways.

Do Non–Audit Service Fees Impair Auditor Independence? Evidence from Going Concern Audit Opinions

Abstract: We find no significant association between non–audit service fees and impaired auditor independence, where auditor independence is surrogated by auditors’ propensity to issue going concern audit opinions. We also find no association between going concern opinions and either total fees or audit fees. In addition, our findings are robust to controlling for unexpected fees, to controlling for endogeneity among our variables, and to several alternative research design specifications. Our results are consistent with market–based incentives, such as loss of reputation and litigation costs, dominating the expected benefits from compromising auditor independence.

Effects of coenzyme Q10 in early Parkinson disease: evidence of slowing of the functional decline.

Abstract: Background Parkinson disease (PD) is a degenerative neurological disorder for which no treatment has been shown to slow the progression. Objective To determine whether a range of dosages of coenzyme Q10is safe and well tolerated and could slow the functional decline in PD. Design Multicenter, randomized, parallel-group, placebo-controlled, double-blind, dosage-ranging trial. Setting Academic movement disorders clinics. Patients Eighty subjects with early PD who did not require treatment for their disability. Interventions Random assignment to placebo or coenzyme Q10at dosages of 300, 600, or 1200 mg/d. Main Outcome Measure The subjects underwent evaluation with the Unified Parkinson Disease Rating Scale (UPDRS) at the screening, baseline, and 1-, 4-, 8-, 12-, and 16-month visits. They were followed up for 16 months or until disability requiring treatment with levodopa had developed. The primary response variable was the change in the total score on the UPDRS from baseline to the last visit. Results The adjusted mean total UPDRS changes were +11.99 for the placebo group, +8.81 for the 300-mg/d group, +10.82 for the 600-mg/d group, and +6.69 for the 1200-mg/d group. ThePvalue for the primary analysis, a test for a linear trend between the dosage and the mean change in the total UPDRS score, was .09, which met our prespecified criteria for a positive trend for the trial. A prespecified, secondary analysis was the comparison of each treatment group with the placebo group, and the difference between the 1200-mg/d and placebo groups was significant (P= .04). Conclusions Coenzyme Q10was safe and well tolerated at dosages of up to 1200 mg/d. Less disability developed in subjects assigned to coenzyme Q10than in those assigned to placebo, and the benefit was greatest in subjects receiving the highest dosage. Coenzyme Q10appears to slow the progressive deterioration of function in PD, but these results need to be confirmed in a larger study.

Get ready for agile methods, with care

Abstract: Although many of their advocates consider the agile and plan-driven software development methods polar opposites, synthesizing the two can provide developers with a comprehensive spectrum of tools and options. Real-world examples argue for and against agile methods. Responding to change has been cited as the critical technical success factor in the Internet browser battle between Microsoft and Netscape. But overresponding to change has been cited as the source of many software disasters, such as the $3 billion overrun of the US Federal Aviation Administration's Advanced Automation System for national air traffic control. The author believes that both agile and plan-driven approaches have a responsible center and overinterpreting radical fringes. Agile and plan-driven methods both form part of the planning spectrum. Thus, while each approach has a home ground within which it performs very well, and much better than the other, a combined approach is feasible and preferable in some circumstances.

Shared Leadership: Reframing the Hows and Whys of Leadership

Abstract: Preface Chapter 1 Introduction - All Those Years Ago: The Historical Underpinnings of Shared Leadership - Craig L. Pearce and Jay A. Conger Chapter 2 Shared Leadership: Paradox and Possibility - Joyce K. Fletcher and Katrin Kaeufer Chapter 3 Toward a Model of Shared Leadership and Distributed Influence in the Innovation Process: How Shared Leadership can Enhance New Product Development Team Dynamics and Effectiveness - Jonathan F. Cox, Craig L. Pearce, and Monica L. Perry Chapter 4 Can Team Members Share Leadership? Foundations in Research and Theory - Anson Seers, Tiffany Keller, and James M. Wilkerson Chapter 5 The Role of Shared Cognition in Enabling Shared Leadership and Team Adaptiability - C. Shawn Burke, Stephen M. Fiore, and Eduardo Salas Chapter 6 Self-leadership and Superleadership: The Heart and Art of Creating Shared Leadership in Teams - Jeffrey D. Houghton, Christopher P. Neck, and Charles C. Manz Chapter 7 Assessing Shared Leadership: Development and Preliminary Validation of a Team Multifactor Leadership Questionnaire - Bruce J. Avolio, Nagaraj Sivasubramaniam, William D. Murry, Dongil Jung, and John W. Garger Chapter 8 A Group Exchange Structure Approach to Leadership in Groups - Scott Seibert, Raymond T. Sparrowe, and Robert C. Liden Chapter 9 Shared Leadership in Work Teams: A Social Network Approach - Margarita Mayo, James R. Meindl, and Juan-Carlos Pastor Chapter 10 Flow, Creativity, and Shared Leadership: Rethinking the Motivation and Structuring of Knowledge Work - Charles Hooker and Mihaly Csikzentmihalyi Chapter 11 Shared Leadership in the Management of Group Boundries: A Study of Expulsions From Officer's Training Courses - Boas Shamir and Yael Lapidot Chapter 12 When Two (or More) Heads are Better Than One: The Promise and Pitfalls of Shared Leadership - James O'Toole, Jay Galbraith, and Edward E. Lawler, III Chapter 13 Leadership, Starting at the Top - Edwin A. Locke Chapter 14 Conclusion - A Research Agenda for Shared Leadership - Craig L. Pearce and Jay A. Conger