Showing papers by "University of Oregon published in 2006"

Risk As Analysis and Risk As Feelings: Some Thoughts About Affect, Reason, Risk, and Rationality

Abstract: Modern theories in cognitive psychology and neuroscience indicate that there are two fundamental ways in which human beings comprehend risk. The analytic system uses algorithms and normative rules, such as probability calculus, formal logic, and risk assessment. It is relatively slow, effortful, and requires conscious control. The experiential system is intuitive, fast, mostly automatic, and not very accessible to conscious awareness. The experiential system enabled human beings to survive during their long period of evolution and remains today the most natural and most common way to respond to risk. It relies on images and associations, linked by experience to emotion and affect (a feeling that something is good or bad). This system represents risk as a feeling that tells us whether it's safe to walk down this dark street or drink this strange-smelling water. Proponents of formal risk analysis tend to view affective responses to risk as irrational. Current wisdom disputes this view. The rational and the experiential systems operate in parallel and each seems to depend on the other for guidance. Studies have demonstrated that analytic reasoning cannot be effective unless it is guided by emotion and affect. Rational decision making requires proper integration of both modes of thought. Both systems have their advantages, biases, and limitations. Now that we are beginning to understand the complex interplay between emotion and reason that is essential to rational behavior, the challenge before us is to think creatively about what this means for managing risk. On the one hand, how do we apply reason to temper the strong emotions engendered by some risk events? On the other hand, how do we infuse needed "doses of feeling" into circumstances where lack of experience may otherwise leave us too "coldly rational"? This article addresses these important questions.

Inequality Regimes Gender, Class, and Race in Organizations

Abstract: In this article, the author addresses two feminist issues: first, how to conceptualize intersectionality, the mutual reproduction of class, gender, and racial relations of inequality, and second, how to identify barriers to creating equality in work organizations. She develops one answer to both issues, suggesting the idea of “inequality regimes” as an analytic approach to understanding the creation of inequalities in work organizations. Inequality regimes are the interlocked practices and processes that result in continuing inequalities in all work organizations. Work organizations are critical locations for the investigation of the continuous creation of complex inequalities because much societal inequality originates in such organizations. Work organizations are also the target for many attempts to alter patterns of inequality: The study of change efforts and the oppositions they engender are often opportunities to observe frequently invisible aspects of the reproduction of inequalities. The concept of...

E‐mail Survey Response Rates: A Review

Abstract: Electronic mail (e-mail) has been used to distribute surveys and collect data from online users for almost fifteen years. However, some have suggested that the use of e-mail is becoming obsolete. This study analyzes response rates to e-mail surveys undertaken since 1986 and examines five influences to response rates: the year the study was undertaken, the number of questions in the survey, the number of pre-notification contacts, the number of follow-up contacts and survey topic salience. Response rates to e-mail surveys have significantly decreased since 1986. Correlation and regression analyses suggest that year that the survey was undertaken and number of follow-up contacts had the most influence on response rates. A discussion of other influences and future research into this area is provided.

Risk Perception and Affect

Abstract: Humans perceive and act on risk in two fundamental ways. Risk as feelings refers to individuals' instinctive and intuitive reactions to danger. Risk as analysis brings logic, reason, and scientific deliberation to bear on risk management. Reliance on risk as feelings is described as “the affect heuristic.” This article traces the development of this heuristic and discusses some of the important ways that it impacts how people perceive and evaluate risk.

Numeracy and Decision Making

Abstract: A series of four studies explored how the ability to comprehend and transform probability numbers relates to performance on judgment and decision tasks. On the surface, the tasks in the four studies appear to be widely different; at a conceptual level, however, they all involve processing numbers and the potential to show an influence of affect. Findings were consistent with highly numerate individuals being more likely to retrieve and use appropriate numerical principles, thus making themselves less susceptible to framing effects, compared with less numerate individuals. In addition, the highly numerate tended to draw different (generally stronger or more precise) affective meaning from numbers and numerical comparisons, and their affective responses were more precise. Although generally helpful, this tendency may sometimes lead to worse decisions. The less numerate were influenced more by competing, irrelevant affective considerations. Analyses showed that the effect of numeracy was not due to general intelligence. Numerical ability appears to matter to judgments and decisions in important ways.

The Tau Parallel Performance System

Abstract: The ability of performance technology to keep pace with the growing complexity of parallel and distributed systems depends on robust performance frameworks that can at once provide system-specific performance capabilities and support high-level performance problem solving Flexibility and portability in empirical methods and processes are influenced primarily by the strategies available for instrmentation and measurement, and how effectively they are integrated and composed This paper presents the TAU (Tuning and Analysis Utilities) parallel performance sytem and describe how it addresses diverse requirements for performance observation and analysis

Development of short and very short forms of the Children's Behavior Questionnaire.

Abstract: Using data from 468 parents and taking into account internal consistency, breadth of item content, within-scale factor analysis, and patterns of missing data, we developed short (94 items, 15 scales) and very short (36 items, 3 broad scales) forms of the Children's Behavior Questionnaire (CBQ; Rothbart, Ahadi, & Hershey, 1994; Rothbart, Ahadi, Hershey, & Fisher, 2001), a well-established parent-report measure of temperament for children aged 3 to 8 years. We subsequently evaluated the forms with data from 1,189 participants. In mid/high-income and White samples, the CBQ short and very short forms demonstrated both satisfactory internal consistency and criterion validity, and exhibited longitudinal stability and cross-informant agreement comparable to that of the standard CBQ. Internal consistency was somewhat lower among African American and low-income samples for some scales. Very short form scales demonstrated acceptable internal consistency for all samples, and confirmatory factor analyses indicated marginal fit of the very short form items to a three-factor model.

The carbon balance of north american wetlands

Abstract: We examine the carbon balance of North American wetlands by reviewing and synthesizing the published literature and soil databases. North American wetlands contain about 220 Pg C, most of which is in peat. They are a small to moderate carbon sink of about 49 Tg C yr−1, although the uncertainty around this estimate is greater than 100%, with the largest unknown being the role of carbon sequestration by sedimentation in freshwater mineral-soil wetlands. We estimate that North American wetlands emit 9 Tg methane (CH4) yr−1; however, the uncertainty of this estimate is also greater than 100%. With the exception of estuarine wetlands, CH4 emissions from wetlands may largely offset any positive benefits of carbon sequestration in soils and plants in terms of climate forcing. Historically, the destruction of wetlands through land-use changes has had the largest effects on the carbon fluxes and consequent radiative forcing of North American wetlands. The primary effects have been a reduction in their ability to sequester carbon (a small to moderate increase in radiative forcing), oxidation of their soil carbon reserves upon drainage (a small increase in radiative forcing), and reduction in CH4 emissions (a small to large decrease in radiative forcing). It is uncertain how global changes will affect the carbon pools and fluxes of North American wetlands. We will not be able to predict accurately the role of wetlands as potential positive or negative feedbacks to anthropogenic global change without knowing the integrative effects of changes in temperature, precipitation, atmospheric carbon dioxide concentrations, and atmospheric deposition of nitrogen and sulfur on the carbon balance of North American wetlands.

Understanding churn in peer-to-peer networks

Abstract: The dynamics of peer participation, or churn, are an inherent property of Peer-to-Peer (P2P) systems and critical for design and evaluation. Accurately characterizing churn requires precise and unbiased information about the arrival and departure of peers, which is challenging to acquire. Prior studies show that peer participation is highly dynamic but with conflicting characteristics. Therefore, churn remains poorly understood, despite its significance.In this paper, we identify several common pitfalls that lead to measurement error. We carefully address these difficulties and present a detailed study using three widely-deployed P2P systems: an unstructured file-sharing system (Gnutella), a content-distribution system (BitTorrent), and a Distributed Hash Table (Kad). Our analysis reveals several properties of churn: (i) overall dynamics are surprisingly similar across different systems, (ii) session lengths are not exponential, (iii) a large portion of active peers are highly stable while the remaining peers turn over quickly, and (iv) peer session lengths across consecutive appearances are correlated. In summary, this paper advances our understanding of churn by improving accuracy, comparing different P2P file sharingdistribution systems, and exploring new aspects of churn.

Evolutionary Response to Rapid Climate Change

Abstract: Recent, rapid climate change is driving evolution, as organisms adapt to altered seasonal events rather than to the direct effects of increasing temperature.

Measurement of fine-grained aspects of toddler temperament: The Early Childhood Behavior Questionnaire.

Abstract: This article describes the development, reliability, and factor structure of a finely differentiated (18 dimensions) parent-report measure of temperament in 1.5- to 3-year-old children, using a cross-sectional sample (N=317) and a longitudinal sample of primary (N=104) and secondary (N=61) caregivers. Adequate internal consistency was demonstrated for all scales and moderate inter-rater reliability was evident for most scales. Longitudinal stability correlations were primarily large over 6- and 12-month spans and moderate to large from 18 to 36 months. Factor analysis revealed a three-factor structure of Surgency/Extraversion, Negative Affectivity, and Effortful Control. In both samples and for both primary and secondary caregivers, older children received higher scores for Attention Focusing, Discomfort, Inhibitory Control, and Positive Anticipation. Primary caregivers rated females higher in Fear, and lower in High-intensity Pleasure, than males; secondary caregivers rated females higher than males in several aspects of Effortful Control.

Hamilton's Ricci Flow

Abstract: Riemannian geometry Fundamentals of the Ricci flow equation Closed 3-manifolds with positive Ricci curvature Ricci solitons and special solutions Isoperimetric estimates and no local collapsing Preparation for singularity analysis High-dimensional and noncompact Ricci flow Singularity analysis Ancient solutions Differential Harnack estimates Space-time geometry Appendix A Geometric analysis related to Ricci flow Appendix B Analytic techniques for geometric flows Appendix S Solutions to selected exercises Bibliography Index

The Development of Executive Functioning and Theory of Mind A Comparison of Chinese and U.S. Preschoolers

Abstract: Preschoolers' theory-of-mind development follows a similar age trajectory across many cultures. To determine whether these similarities are related to similar underlying ontogenetic processes, we examined whether the relation between theory of mind and executive function commonly found among U.S. preschoolers is also present among Chinese preschoolers. Preschoolers from Beijing, China (N= 109), were administered theory-of-mind and executive-functioning tasks, and their performance was compared with that of a previously studied sample of U.S. preschoolers (N= 107). The Chinese preschoolers outperformed their U.S. counterparts on all measures of executive functioning, but were not similarly advanced in theory-of-mind reasoning. Nonetheless, individual differences in executive functioning predicted theory of mind for children in both cultures. Thus, the relation between executive functioning and theory of mind is robust across two disparate cultures. These findings shed light on why executive functioning is important for theory-of-mind development.

The physics of premelted ice and its geophysical consequences

Abstract: The surface of ice exhibits the swath of phase-transition phenomena common to all materials and as such it acts as an ideal test bed of both theory and experiment. It is readily available, transparent, optically birefringent, and probing it in the laboratory does not require cryogenics or ultrahigh vacuum apparatus. Systematic study reveals the range of critical phenomena, equilibrium and nonequilibrium phase-transitions, and, most relevant to this review, premelting, that are traditionally studied in more simply bound solids. While this makes investigation of ice as a material appealing from the perspective of the physicist, its ubiquity and importance in the natural environment also make ice compelling to a broad range of disciplines in the Earth and planetary sciences. In this review we describe the physics of the premelting of ice and its relationship with the behavior of other materials more familiar to the condensed-matter community. A number of the many tendrils of the basic phenomena as they play out on land, in the oceans, and throughout the atmosphere and biosphere are developed.

Evolution of Hormone-Receptor Complexity by Molecular Exploitation

Abstract: According to Darwinian theory, complexity evolves by a stepwise process of elaboration and optimization under natural selection. Biological systems composed of tightly integrated parts seem to challenge this view, because it is not obvious how any element's function can be selected for unless the partners with which it interacts are already present. Here we demonstrate how an integrated molecular system-the specific functional interaction between the steroid hormone aldosterone and its partner the mineralocorticoid receptor-evolved by a stepwise Darwinian process. Using ancestral gene resurrection, we show that, long before the hormone evolved, the receptor's affinity for aldosterone was present as a structural by-product of its partnership with chemically similar, more ancient ligands. Introducing two amino acid changes into the ancestral sequence recapitulates the evolution of present-day receptor specificity. Our results indicate that tight interactions can evolve by molecular exploitation-recruitment of an older molecule, previously constrained for a different role, into a new functional complex.

Oral Reading Fluency Norms: A Valuable Assessment Tool for Reading Teachers

Abstract: In 1992, the authors collaborated to develop a set of norms for oral reading fluency for grades 2–5. Since then, interest in and awareness of fluency has greatly increased, and Hasbrouck and Tindal have collaborated further to compile an updated and expanded set of norms for grades 1–8. This article discusses the application of these norms to three important assessment activities related to improving students' reading achievement: Screening students for possible reading problems Diagnosing deficits in students' fluency Monitoring the progress of students receiving supplementary instruction or intensive intervention in reading An overview of the history and purpose for developing measures of oral reading fluency is also presented.

Explaining sex differences in dental caries prevalence: saliva, hormones, and "life-history" etiologies.

Abstract: When dental caries rates are reported by sex, females are typically found to ex- hibit higher prevalence rates than males. This finding is generally true for diverse cultures with different subsistence systems and for a wide range of chronological periods. Exceptions exist, but are not common. In this paper, we present new data for sex differences in dental caries rates among the Guanches (Tenerife, Canary Islands), summarize results of meta-analyses of dental caries prevalence, and emphasize new research that stresses the critical role of female hor- mones and life-history events in the etiology of dental caries. Among the Guanches, corrected tooth-count caries rates for females (8.8%, 158/1,790) are approximately twice the frequency of caries among males (4.5%, 68/1,498). Higher caries prevalence among females is often explained by one of three factors: 1) earlier eruption of teeth in girls, hence longer exposure of girls' teeth to the cariogenic oral environment, 2) easier access to food supplies by women and frequent snacking during food preparation, and 3) pregnancy. Anthropologists tend to favor explanations involving behavior, including sexual division of labor and women's domestic role in food produc- tion. By contrast, the causal pathways through which pregnancy contributes to poorer oral health and higher caries rates are deemphasized or discounted. This paper presents recent research on physiological changes associated with fluctuating hormone levels during individual life histories, and the impact these changes have on the oral health of women. The biochemical composition of saliva and overall saliva flow rate are modified in several important ways by hormonal fluctuations during events such as puberty, menstruation, and pregnancy, making the oral environment significantly more cariogenic for women than for men. These results suggest that hormonal fluctuations can have a dramatic effect on the oral health of women, and constitute an important causal factor in explaining sex differences in caries rates. Am. J. Hum.

Search for neutral MSSM Higgs bosons at LEP

Abstract: The four LEP collaborations, ALEPH, DELPHI, L3 and OPAL, have searched for the neutral Higgs bosons which are predicted by the Minimal Supersymmetric standard model (MSSM). The data of the four collaborations are statistically combined and examined for their consistency with the background hypothesis and with a possible Higgs boson signal. The combined LEP data show no significant excess of events which would indicate the production of Higgs bosons. The search results are used to set upper bounds on the cross-sections of various Higgs-like event topologies. The results are interpreted within the MSSM in a number of “benchmark” models, including CP-conserving and CP-violating scenarios. These interpretations lead in all cases to large exclusions in the MSSM parameter space. Absolute limits are set on the parameter cosβ and, in some scenarios, on the masses of neutral Higgs bosons.

Novel Chromophores and Buried Charges Control Color in mFruits

Abstract: mFruits are second-generation monomeric red fluorescent proteins (mRFPs) that have improved brightness and photostability compared to the first-generation mRFP1. The emission and excitation maxima are distributed over the remarkably large ranges of about 550-650 and 540-590 nm, respectively; however, the variations in the spectra can be traced to a few key amino acids. Spectroscopic and atomic resolution crystallographic analyses of three representatives, mOrange, mStrawberry, and mCherry, reveal that different mechanisms operate to establish the excitation and emission maxima. Evidently, they all undergo the second oxidation step to produce an acylimine linkage in the polypeptide backbone. In comparison to the progenitor DsRed, direct covalent modification to this linkage (mOrange) and indirect modification of the chromophore environment (mStrawberry and mCherry) produce strong blue- and red-shifted variants. The blue shift of mOrange is induced by an unprecedented covalent modification of the protein backbone. The electron-density map indicates the formation of a third heterocycle, 2-hydroxy-dihydrooxazole, upon the reaction of Thr 66 Ogamma with the polypeptide backbone, which in turn reduces the conjugation of the carbonyl at position 65 with the rest of the chromophore. In mStrawberry and mCherry, the movement of charged Lys 70 and protonation of Glu 215 are proposed to modify the chromophore electron-density distribution, inducing the red shift. pH-dependent spectral shifts of mCherry and mStrawberry appear to result from the titration of Glu 215, although, for mStrawberry, partial cyclization of Thr 66 may contribute at high pH.

Self-propelled Leidenfrost droplets.

Abstract: We report that liquids perform self-propelled motion when they are placed in contact with hot surfaces with asymmetric (ratchetlike) topology. The pumping effect is observed when the liquid is in the Leidenfrost regime (the film-boiling regime), for many liquids and over a wide temperature range. We propose that liquid motion is driven by a viscous force exerted by vapor flow between the solid and the liquid.

Shoulder Function and 3-Dimensional Scapular Kinematics in People With and Without Shoulder Impingement Syndrome

Abstract: Background and Purpose. Several factors such as posture, muscle force, range of motion, and scapular dysfunction are commonly believed to contribute to shoulder impingement. The purpose of this study was to compare 3-dimensional scapular kinematics, shoulder range of motion, shoulder muscle force, and posture in subjects with and without primary shoulder impingement syndrome. Subjects. Forty-five subjects with impingement syndrome were recruited and compared with 45 subjects without known pathology or impairments matched by age, sex, and hand dominance. Methods. Shoulder motion and thoracic spine posture were measured goniometrically, and force was measured with a dynamometer. An electromagnetic motion analysis system was used to capture shoulder kinematics during active elevation in both the sagittal and scapular planes as well as during external rotation with the arm at 90 degrees of elevation in the frontal plane. Results. The impingement group demonstrated slightly greater scapular upward rotation and clavicular elevation during flexion and slightly greater scapular posterior tilt and clavicular retraction during scapular-plane elevation compared with the control group. The impingement group demonstrated less range of motion and force in all directions compared with the control group. There were no differences in resting posture between the groups. Discussion and Conclusion. The kinematic differences found in subjects with impingement may represent scapulothoracic compensatory strategies for glenohumeral weakness or motion loss. The decreased range of motion and force found in subjects with impingement support rehabilitation approaches that focus on strengthening and restoring flexibility.

A straightforward introduction to continuous quantum measurement

Abstract: We present a pedagogical treatment of the formalism of continuous quantum measurement. Our aim is to show the reader how the equations describing such measurements are derived and manipulated in a direct manner. We also give elementary background material for those new to measurement theory, and describe further various aspects of continuous measurements that should be helpful to those wanting to use such measurements in applications. Specifically, we use the simple and direct approach of generalized measurements to derive the stochastic master equation describing the continuous measurements of observables, give a tutorial on stochastic calculus, treat multiple observers and inefficient detection, examine a general form of the measurement master equation, and show how the master equation leads to information gain and disturbance. To conclude, we give a detailed treatment of imaging the resonance fluorescence from a single atom as a concrete example of how a continuous position measurement arises in a physical system.

Knowing your place: self-perceptions of status in face-to-face groups.

Abstract: Status is the prominence, respect, and influence individuals enjoy in the eyes of others. Theories of positive illusions suggest that individuals form overly positive perceptions of their status in face-to-face groups. In contrast, the authors argue that individuals' perceptions of their status are highly accurate--that is, they closely match the group's perception of their status--because forming overly positive status self-perceptions can damage individuals' acceptance in a group. Therefore, the authors further argue that individuals are likely to refrain from status self-enhancement to maintain their belongingness in a group. Support for their hypotheses was found in 2 studies of status in face-to-face groups, using a social relations model approach (D. A. Kenny & L. La Voie, 1984). Individuals showed high accuracy in perceiving their status and even erred on the side of being overly humble. Moreover, enhancement in status self-perceptions was associated with lower levels of social acceptance.

The time course of consolidation in visual working memory.

Abstract: How long does it take to form a durable representation in visual working memory? Several theorists have proposed that this consolidation process is very slow. Here, we measured the time course of consolidation. Observers performed a change-detection task for colored squares, and shortly after the presentation of the first array, pattern masks were presented at the locations of each of the colored squares to disrupt representations that had not yet been consolidated. Performance on the memory task was impaired when the delay between the colored squares and the masks was short, and this effect became larger when the number of colored squares was increased. The rate of consolidation was approximately 50 ms per item, which is considerably faster than previous proposals.

Creative Self-Efficacy: Correlates in Middle and Secondary Students

Abstract: This study examined correlates of creative self-efficacy (i.e., self-judgments of creative ability) in middle and secondary students (N = 1,322). Results indicate that students' mastery- and performance-approach beliefs and teacher feedback on creative ability were positively related to students' creative self-efficacy. Creative self-efficacy was also linked to student reports of their teachers not listening to them and sometimes feeling that their teachers had given up on them. Students with higher levels of creative self-efficacy were significantly more likely to hold more positive beliefs about their academic abilities in all subject areas and were significantly more likely to indicate that they planned to attend college than students with lower levels of creative self-efficacy. Finally, students with higher levels of creative self-efficacy were significantly more likely to report higher levels of participation in after-school academics and after- school group activities. Implications for cre...

Directed evolution of a monomeric, bright and photostable version of Clavularia cyan fluorescent protein: structural characterization and applications in fluorescence imaging

Abstract: The arsenal of engineered variants of the GFP [green FP (fluorescent protein)] from Aequorea jellyfish provides researchers with a powerful set of tools for use in biochemical and cell biology research. The recent discovery of diverse FPs in Anthozoa coral species has provided protein engineers with an abundance of alternative progenitor FPs from which improved variants that complement or supersede existing Aequorea GFP variants could be derived. Here, we report the engineering of the first monomeric version of the tetrameric CFP (cyan FP) cFP484 from Clavularia coral. Starting from a designed synthetic gene library with mammalian codon preferences, we identified dimeric cFP484 variants with fluorescent brightness significantly greater than the wild-type protein. Following incorporation of dimer-breaking mutations and extensive directed evolution with selection for blue-shifted emission, high fluorescent brightness and photostability, we arrived at an optimized variant that we have named mTFP1 [monomeric TFP1 (teal FP 1)]. The new mTFP1 is one of the brightest and most photostable FPs reported to date. In addition, the fluorescence is insensitive to physiologically relevant pH changes and the fluorescence lifetime decay is best fitted as a single exponential. The 1.19 A crystal structure (1 A=0.1 nm) of mTFP1 confirms the monomeric structure and reveals an unusually distorted chromophore conformation. As we experimentally demonstrate, the high quantum yield of mTFP1 (0.85) makes it particularly suitable as a replacement for ECFP (enhanced CFP) or Cerulean as a FRET (fluorescence resonance energy transfer) donor to either a yellow or orange FP acceptor.