Showing papers by "University of Minnesota published in 2007"

Top 10 algorithms in data mining

Abstract: This paper presents the top 10 data mining algorithms identified by the IEEE International Conference on Data Mining (ICDM) in December 2006: C4.5, k-Means, SVM, Apriori, EM, PageRank, AdaBoost, kNN, Naive Bayes, and CART. These top 10 algorithms are among the most influential data mining algorithms in the research community. With each algorithm, we provide a description of the algorithm, discuss the impact of the algorithm, and review current and further research on the algorithm. These 10 algorithms cover classification, clustering, statistical learning, association analysis, and link mining, which are all among the most important topics in data mining research and development.

The Sublethal Effects of Pesticides on Beneficial Arthropods

Abstract: Traditionally, measurement of the acute toxicity of pesticides to beneficial arthropods has relied largely on the determination of an acute median lethal dose or concentration. However, the estimated lethal dose during acute toxicity tests may only be a partial measure of the deleterious effects. In addition to direct mortality induced by pesticides, their sublethal effects on arthropod physiology and behavior must be considered for a complete analysis of their impact. An increasing number of studies and methods related to the identification and characterization of these effects have been published in the past 15 years. Review of sublethal effects reported in published literature, taking into account recent data, has revealed new insights into the sublethal effects of pesticides including effects on learning performance, behavior, and neurophysiology. We characterize the different types of sublethal effects on beneficial arthropods, focusing mainly on honey bees and natural enemies, and we describe the methods used in these studies. Finally, we discuss the potential for developing experimental approaches that take into account these sublethal effects in integrated pest management and the possibility of integrating their evaluation in pesticide registration procedures.

On the Energy Detection of Unknown Signals Over Fading Channels

Abstract: This letter addresses the problem of energy detection of an unknown signal over a multipath channel. It starts with the no-diversity case, and presents some alternative closed-form expressions for the probability of detection to those recently reported in the literature. Detection capability is boosted by implementing both square-law combining and square-law selection diversity schemes

The Chlamydomonas Genome Reveals the Evolution of Key Animal and Plant Functions

Abstract: Chlamydomonas reinhardtii is a unicellular green alga whose lineage diverged from land plants over 1 billion years ago. It is a model system for studying chloroplast-based photosynthesis, as well as the structure, assembly, and function of eukaryotic flagella (cilia), which were inherited from the common ancestor of plants and animals, but lost in land plants. We sequenced the approximately 120-megabase nuclear genome of Chlamydomonas and performed comparative phylogenomic analyses, identifying genes encoding uncharacterized proteins that are likely associated with the function and biogenesis of chloroplasts or eukaryotic flagella. Analyses of the Chlamydomonas genome advance our understanding of the ancestral eukaryotic cell, reveal previously unknown genes associated with photosynthetic and flagellar functions, and establish links between ciliopathy and the composition and function of flagella.

The Strength Model of Self-Control

Abstract: Self-control is a central function of the self and an important key to success in life. The exertion of self-control appears to depend on a limited resource. Just as a muscle gets tired from exertion, acts of self-control cause short-term impairments (ego depletion) in subsequent self-control, even on unrelated tasks. Research has supported the strength model in the domains of eating, drinking, spending, sexuality, intelligent thought, making choices, and interpersonal behavior. Motivational or framing factors can temporarily block the deleterious effects of being in a state of ego depletion. Blood glucose is an important component of the energy.

Genome-wide association study identifies novel breast cancer susceptibility loci

Abstract: Breast cancer exhibits familial aggregation, consistent with variation in genetic susceptibility to the disease. Known susceptibility genes account for less than 25% of the familial risk of breast cancer, and the residual genetic variance is likely to be due to variants conferring more moderate risks. To identify further susceptibility alleles, we conducted a two-stage genome-wide association study in 4,398 breast cancer cases and 4,316 controls, followed by a third stage in which 30 single nucleotide polymorphisms (SNPs) were tested for confirmation in 21,860 cases and 22,578 controls from 22 studies. We used 227,876 SNPs that were estimated to correlate with 77% of known common SNPs in Europeans at r2.0.5. SNPs in five novel independent loci exhibited strong and consistent evidence of association with breast cancer (P,1027). Four of these contain plausible causative genes (FGFR2, TNRC9, MAP3K1 and LSP1). At the second stage, 1,792 SNPs were significant at the P,0.05 level compared with an estimated 1,343 that would be expected by chance, indicating that many additional common susceptibility alleles may be identifiable by this approach.

The Power of Personality: The Comparative Validity of Personality Traits, Socioeconomic Status, and Cognitive Ability for Predicting Important Life Outcomes:

Abstract: The ability of personality traits to predict im- portant life outcomes has traditionally been questioned because of the putative small effects of personality. In this article, we compare the predictive validity of personality traits with that of socioeconomic status (SES) and cogni- tive ability to test the relative contribution of personality traits to predictions of three critical outcomes: mortality, divorce, andoccupationalattainment.Onlyevidence from prospective longitudinal studies was considered. In addi- tion, an attempt was made to limit the review to studies that controlled for important background factors. Results showed that the magnitude of the effects of personality traits on mortality, divorce, and occupational attainment wasindistinguishablefrom the effectsofSES and cognitive ability on these outcomes. These results demonstrate the influence of personality traits on important life outcomes, highlight the need to more routinely incorporate measures of personality into quality of life surveys, and encourage further research about the developmental origins of per- sonality traits and the processes by which these traits in- fluence diverse life outcomes.

Collaborative filtering recommender systems

Abstract: One of the potent personalization technologies powering the adaptive web is collaborative filtering. Collaborative filtering (CF) is the process of filtering or evaluating items through the opinions of other people. CF technology brings together the opinions of large interconnected communities on the web, supporting filtering of substantial quantities of data. In this chapter we introduce the core concepts of collaborative filtering, its primary uses for users of the adaptive web, the theory and practice of CF algorithms, and design decisions regarding rating systems and acquisition of ratings. We also discuss how to evaluate CF systems, and the evolution of rich interaction interfaces. We close the chapter with discussions of the challenges of privacy particular to a CF recommendation service and important open research questions in the field.

The neurobiology of stress and development.

Abstract: Stress is a part of every life to varying degrees, but individuals differ in their stress vulnerability. Stress is usefully viewed from a biological perspective; accordingly, it involves activation of neurobiological systems that preserve viability through change or allostasis. Although they are necessary for survival, frequent neurobiological stress responses increase the risk of physical and mental health problems, perhaps particularly when experienced during periods of rapid brain development. Recently, advances in noninvasive measurement techniques have resulted in a burgeoning of human developmental stress research. Here we review the anatomy and physiology of stress responding, discuss the relevant animal literature, and briefly outline what is currently known about the psychobiology of stress in human development, the critical role of social regulation of stress neurobiology, and the importance of individual differences as a lens through which to approach questions about stress experiences during development and child outcomes.

Use of a Continuous-Flow Device in Patients Awaiting Heart Transplantation

Abstract: A b s t r ac t Background The use of left ventricular assist devices is an accepted therapy for patients with refractory heart failure, but current pulsatile volume-displacement devices have limitations (including large pump size and limited long-term mechanical durability) that have reduced widespread adoption of this technology. Continuous-flow pumps are newer types of left ventricular assist devices developed to overcome some of these limitations. Methods In a prospective, multicenter study without a concurrent control group, 133 patients with end-stage heart failure who were on a waiting list for heart transplantation underwent implantation of a continuous-flow pump. The principal outcomes were the proportions of patients who, at 180 days, had undergone transplantation, had cardiac recovery, or had ongoing mechanical support while remaining eligible for transplantation. We also assessed functional status and quality of life. Results The principal outcomes occurred in 100 patients (75%). The median duration of support was 126 days (range, 1 to 600). The survival rate during support was 75% at 6 months and 68% at 12 months. At 3 months, therapy was associated with significant improvement in functional status (according to the New York Heart Association class and results of a 6-minute walk test) and in quality of life (according to the Minnesota Living with Heart Failure and Kansas City Cardiomyopathy questionnaires). Major adverse events included postoperative bleeding, stroke, right heart failure, and percutaneous lead infection. Pump thrombosis occurred in two patients. Conclusions A continuous-flow left ventricular assist device can provide effective hemodynamic support for a period of at least 6 months in patients awaiting heart transplantation, with improved functional status and quality of life. (ClinicalTrials.gov number, NCT00121472.)

A Multi-State Constraint Kalman Filter for Vision-aided Inertial Navigation

Abstract: In this paper, we present an extended Kalman filter (EKF)-based algorithm for real-time vision-aided inertial navigation. The primary contribution of this work is the derivation of a measurement model that is able to express the geometric constraints that arise when a static feature is observed from multiple camera poses. This measurement model does not require including the 3D feature position in the state vector of the EKF and is optimal, up to linearization errors. The vision-aided inertial navigation algorithm we propose has computational complexity only linear in the number of features, and is capable of high-precision pose estimation in large-scale real-world environments. The performance of the algorithm is demonstrated in extensive experimental results, involving a camera/IMU system localizing within an urban area.

How Emotion Shapes Behavior: Feedback, Anticipation, and Reflection, Rather Than Direct Causation

Abstract: Fear causes fleeing and thereby saves lives: this exemplifies a popular and common sense but increasingly untenable view that the direct causation of behavior is the primary function of emotion. Instead, the authors develop a theory of emotion as a feedback system whose influence on behavior is typically indirect. By providing feedback and stimulating retrospective appraisal of actions, conscious emotional states can promote learning and alter guidelines for future behavior. Behavior may also be chosen to pursue (or avoid) anticipated emotional outcomes. Rapid, automatic affective responses, in contrast to the full-blown conscious emotions, may inform cognition and behavioral choice and thereby help guide current behavior. The automatic affective responses may also remind the person of past emotional outcomes and provide useful guides as to what emotional outcomes may be anticipated in the present. To justify replacing the direct causation model with the feedback model, the authors review a large body of empirical findings.

Descriptive epidemiology of collegiate men's football injuries: National Collegiate Athletic Association Injury Surveillance System, 1988-1989 through 2003-2004

Abstract: Objective: To review 16 years of National Collegiate Athletic Association injury surveillance data for women’s lacrosse and identify potential areas for injury prevention initiatives. Background: Women’s lacrosse is a fast-paced, primarily noncontact sport. Participation in collegiate women’s lacrosse almost doubled between the 1988–1989 and 2003–2004 seasons. Lacrosse equipment consists of sticks made of wood or a synthetic material and a hard rubber ball. Until recently, mouth guards were the only required protective equipment. Main Results: Collegiate women’s lacrosse game injury rates increased over the 16-year study period. More than 60% of all severe game injuries were lower extremity sprains and strains and knee internal derangements, most frequently the result of noncontact incidents. The most common injury scenarios by injury mechanism and player activity were no contact while ball handling (16.4%) and contact from a stick while ball handling (10.5%). Contact from a stick or a ball accounted for 5.6% and 5.2% of injuries sustained during shooting activities, respectively. Approximately 22% of all game and 12% of all practice injuries involved the head and neck. Contact from a stick accounted for the majority (56.0%) of above-the-neck injuries in games; contact from the ball accounted for 20.0% of these injuries. Participants had 5 times the risk of sustaining a concussion in a game as in a practice (0.70 versus 0.15 injuries per 1000 athletic-exposures, rate ratio 4.7, 95% confidence interval 3.8, 6.5). Recommendations: To reduce the lower extremity injuries that comprise the greatest injury burden in women’s lacrosse, future researchers should evaluate proprioceptive, plyometric, and balance training interventions designed specifically for female players. Other research areas of great interest involve determining whether protective eyewear (mandated in 2004) reduces injuries to the eye, orbit, and nasal area and identifying any unintended consequences of the mandate, such as increased risk of injuries to other areas of the face or more aggressive play.

The severity of supply chain disruptions: Design characteristics and mitigation capabilities

Abstract: Supply chain disruptions and the associated operational and financial risks represent the most pressing concern facing firms that compete in today's global marketplace. Extant research has not only confirmed the costly nature of supply chain disruptions but has also contributed relevant insights on such related issues as supply chain risks, vulnerability, resilience, and continuity. In this conceptual note, we focus on a relatively unexplored issue, asking and answering the question of how and why one supply chain disruption would be more severe than another. In doing so, we argue, de facto, that supply chain disruptions are unavoidable and, as a consequence, that all supply chains are inherently risky. Employing a multiple-method, multiple-source empirical research design, we derive novel insights, presented as six propositions that relate the severity of supply chain disruptions (i) to the three supply chain design characteristics of density, complexity, and node criticality and (ii) to the two supply chain mitigation capabilities of recovery and warning. These findings not only augment existing knowledge related to supply chain risk, vulnerability, resilience, and business continuity planning but also call into question the wisdom of pursuing such practices as supply base reduction, global sourcing, and sourcing from supply clusters.

Trinucleotide Repeat Disorders

Abstract: The discovery that expansion of unstable repeats can cause a variety of neurological disorders has changed the landscape of disease-oriented research for several forms of mental retardation, Huntington disease, inherited ataxias, and muscular dystrophy. The dynamic nature of these mutations provided an explanation for the variable phenotype expressivity within a family. Beyond diagnosis and genetic counseling, the benefits from studying these disorders have been noted in both neurobiology and cell biology. Examples include insight about the role of translational control in synaptic plasticity, the role of RNA processing in the integrity of muscle and neuronal function, the importance of Fe-S-containing enzymes for cellular energy, and the dramatic effects of altering protein conformations on neuronal function and survival. It is exciting that within a span of 15 years, pathogenesis studies of this class of disorders are beginning to reveal pathways that are potential therapeutic targets.

Antenatal maternal stress and long-term effects on child neurodevelopment: how and why?

Abstract: We review a significant body of evidence from independent prospective studies that if a mother is stressed while pregnant, her child is substantially more likely to have emotional or cognitive problems, including an increased risk of attentional deficit/hyperactivity, anxiety, and language delay. These findings are independent of effects due to maternal postnatal depression and anxiety. We still do not know what forms of anxiety or stress are most detrimental, but research suggests that the relationship with the partner can be important in this respect. The magnitude of these effects is clinically significant, as the attributable load of emotional/behavioral problems due to antenatal stress and/or anxiety is approximately 15%. Animal models suggest that activity of the stress-responsive hypothalamic-pituitary-adrenal (HPA) axis and its hormonal end-product cortisol are involved in these effects in both mother and offspring. The fetal environment can be altered if stress in the mother changes her hormonal profile, and in humans, there is a strong correlation between maternal and fetal cortisol levels. However, many problems remain in understanding the mechanisms involved in this interaction. For example, maternal cortisol responses to stress decline over the course of pregnancy, and earlier in pregnancy, the link between maternal and fetal cortisol is less robust. It is possible that the effects of maternal anxiety and stress on the developing fetus and child are moderated by other factors such as a maternal diet (e.g., protein load). It is suggested that extra vigilance or anxiety, readily distracted attention, or a hyper-responsive HPA axis may have been adaptive in a stressful environment during evolution, but exists today at the cost of vulnerability to neurodevelopmental disorders.

Psychometric evaluation and calibration of health-related quality of life item banks: plans for the Patient-Reported Outcomes Measurement Information System (PROMIS).

Abstract: Background: The construction and evaluation of item banks to measure unidimensional constructs of health-related quality of life (HRQOL) is a fundamental objective of the Patient-Reported Outcomes Measurement Information System (PROMIS) project. Objectives: Item banks will be used as the foundation for developing short-form instruments and enabling computerized adaptive testing. The PROMIS Steering Committee selected 5 HRQOL domains for initial focus: physical functioning, fatigue, pain, emotional distress, and social role participation. This report provides an overview of the methods used in the PROMIS item analyses and proposed calibration of item banks. Analyses: Analyses include evaluation of data quality (eg, logic and range checking, spread of response distribution within an item), descriptive statistics (eg, frequencies, means), item response theory model assumptions (unidimensionality, local independence, monotonicity), model fit, differential item functioning, and item calibration for banking. Recommendations: Summarized are key analytic issues; recommendations are provided for future evaluations of item banks in HRQOL assessment.

Psychology as the science of self-reports and finger movements: Whatever happened to actual behavior?

Abstract: Psychology calls itself the science of behavior, and the American Psychological Association's current "Decade of Behavior" was intended to increase awareness and appreciation of this aspect of the science. Yet some psychological subdisciplines have never directly studied behavior, and studies on behavior are dwindling rapidly in other subdisciplines. We discuss the eclipse of behavior in personality and social psychology, in which direct observation of behavior has been increasingly supplanted by introspective self-reports, hypothetical scenarios, and questionnaire ratings. We advocate a renewed commitment to including direct observation of behavior whenever possible and in at least a healthy minority of research projects.

Insulin signalling to mTOR mediated by the Akt/PKB substrate PRAS40.

Abstract: Insulin stimulates protein synthesis and cell growth by activation of the protein kinases Akt (also known as protein kinase B, PKB) and mammalian target of rapamycin (mTOR). It was reported that Akt activates mTOR by phosphorylation and inhibition of tuberous sclerosis complex 2 (TSC2). However, in recent studies the physiological requirement of Akt phosphorylation of TSC2 for mTOR activation has been questioned. Here, we identify PRAS40 (proline-rich Akt/PKB substrate 40 kDa) as a novel mTOR binding partner that mediates Akt signals to mTOR. PRAS40 binds the mTOR kinase domain and its interaction with mTOR is induced under conditions that inhibit mTOR signalling, such as nutrient or serum deprivation or mitochondrial metabolic inhibition. Binding of PRAS40 inhibits mTOR activity and suppresses constitutive activation of mTOR in cells lacking TSC2. PRAS40 silencing inactivates insulin-receptor substrate-1 (IRS-1) and Akt, and uncouples the response of mTOR to Akt signals. Furthermore, PRAS40 phosphorylation by Akt and association with 14-3-3, a cytosolic anchor protein, are crucial for insulin to stimulate mTOR. These findings identify PRAS40 as an important regulator of insulin sensitivity of the Akt-mTOR pathway and a potential target for the treatment of cancers, insulin resistance and hamartoma syndromes.

Interpersonal deviance, organizational deviance, and their common correlates: a review and meta-analysis.

Abstract: Interpersonal deviance (ID) and organizational deviance (OD) are highly correlated (R. S. Dalal, 2005). This, together with other empirical and theoretical evidence, calls into question the separability of ID and OD. As a further investigation into their separability, relationships among ID, OD, and their common correlates were meta-analyzed. ID and OD were highly correlated (rho = .62) but had differential relationships with key Big Five variables and organizational citizenship behaviors, which lends support to the separability of ID and OD. Whether the R. J. Bennett and S. L. Robinson (2000) instrument was used moderated some relationships. ID and OD exhibited their strongest (negative) relationships with organizational citizenship, Agreeableness, Conscientiousness, and Emotional Stability. Correlations with organizational justice were small to moderate, and correlations with demographic variables were generally negligible.

One-Year Cardiovascular Event Rates in Outpatients With Atherothrombosis

Abstract: ContextFew data document current cardiovascular (CV) event rates in stable patients with atherothrombosis in a community setting. Differential event rates for patients with documented coronary artery disease (CAD), cerebrovascular disease (CVD), or peripheral arterial disease (PAD) or those at risk of these diseases have not been previously evaluated in a single international cohort.ObjectiveTo establish contemporary, international, 1-year CV event rates in outpatients with established arterial disease or with multiple risk factors for atherothrombosis.Design, Setting, and ParticipantsThe Reduction of Atherothrombosis for Continued Health (REACH) Registry is an international, prospective cohort of 68 236 patients with either established atherosclerotic arterial disease (CAD, PAD, CVD; n = 55 814) or at least 3 risk factors for atherothrombosis (n = 12 422), who were enrolled from 5587 physician practices in 44 countries in 2003-2004.Main Outcome MeasuresRates of CV death, myocardial infarction (MI), and stroke.ResultsAs of July 2006, 1-year outcomes were available for 95.22% (n = 64 977) of participants. Cardiovascular death, MI, or stroke rates were 4.24% overall: 4.69% for those with established atherosclerotic arterial disease vs 2.15% for patients with multiple risk factors only. Among patients with established disease, CV death, MI, or stroke rates were 4.52% for patients with CAD, 6.47% for patients with CVD, and 5.35% for patients with PAD. The incidences of the end point of CV death, MI, or stroke or of hospitalization for atherothrombotic event(s) were 15.20% for CAD, 14.53% for CVD, and 21.14% for PAD patients with established disease. These event rates increased with the number of symptomatic arterial disease locations, ranging from 5.31% for patients with risk factors only to 12.58% for patients with 1, 21.14% for patients with 2, and 26.27% for patients with 3 symptomatic arterial disease locations (P<.001 for trend).ConclusionsIn this large, contemporary, international study, outpatients with established atherosclerotic arterial disease, or at risk of atherothrombosis, experienced relatively high annual CV event rates. Multiple disease locations increased the 1-year risk of CV events.