62,974 research outputs found
Attachment priming and avoidant personality features as predictors of social-evaluation biases
Personality research has shown that negativity in social situations (e.g., negative evaluations of others) can be reduced by the activation of participants' sense of attachment security. Individuals with avoidant personality disorder (APD), however, are theoretically less responsive to context or situational cues because of the inflexible nature of their personality disposition. This idea of individual differences in context-responsiveness was tested in a sample of 169 undergraduates who were assessed for APD features and assigned to positive, negative, or neutral attachment priming conditions. More pronounced APD features were associated with more negative responses to vignettes describing potentially distressing social situations. A significant interaction showed that participants with more avoidant features consistently appraised the vignettes relatively more negatively, regardless of priming condition. Those without APD features, by contrast, did not exhibit negative appraisals/evaluations unless negatively primed (curvilinear effect). This effect could not be explained by depression, current mood, or attachment insecurity, all of which related to negative evaluative biases, but none of which related to situation inflexibility. These findings provide empirical support for the notion that negative information-processing is unusually inflexible and context-unresponsive among individuals with more pronounced features of APD
Labor Supply Effects of Social Insurance
This chapter examines the labor supply effects of social insurance programs. We argue that this topic deserves separate treatment from the rest of the labor supply literature because individuals may be imperfectly informed as to the rules of the programs and because key parameters are likely to differ for those who are eligible for social insurance programs, such as the disabled. Furthermore, differences in social insurance programs often provide natural experiments with exogenous changes in wages or incomes that can be used to estimate labor supply responses. Finally, social insurance often affects different margins of labor supply. For example, the labor supply literature deals mostly with adjustments in the number of hours worked, whereas the incentives of social insurance programs frequently affect the decision of whether to work at all. The empirical work on unemployment insurance (UI) and workers' compensation (WC) insurance finds that the programs tend to increase the length of time employees spend out of work. Most of the estimates of the elasticities of lost work time that incorporate both the incidence and duration of claims are close to 1.0 for unemployment insurance and between 0.5 and 1.0 for workers' compensation. These elasticities are substantially larger than the labor supply elasticities typically found for men in studies of the effects of wages or taxes on hours of work. The evidence on disability insurance and (especially) social security retirement suggests much smaller and less conclusively established labor supply effects. Part of the explanation for this difference probably lies in the fact that UI and WC lead to short-run variation in wages with mostly a substitution effect. Our review suggest that it would be misleading to apply a universal set of labor supply elasticities to these diverse problems and populations.
Nuclear Reactions Rates Governing the Nucleosynthesis of Ti44
Large excesses of Ca44 in certain presolar graphite and silicon carbide
grains give strong evidence for Ti44 production in supernovae. Furthermore,
recent detection of the Ti44 gamma-line from the Cas A SNR by CGRO/COMPTEL
shows that radioactive Ti44 is produced in supernovae. These make the Ti44
abundance an observable diagnostic of supernovae. Through use of a nuclear
reaction network, we have systematically varied reaction rates and groups of
reaction rates to experimentally identify those that govern Ti44 abundance in
core-collapse supernova nucleosynthesis. We survey the nuclear-rate dependence
by repeated calculations of the identical adiabatic expansion, with peak
temperature and density chosen to be 5.5xE9 K and 1E7 g/cc, respectively, to
approximate the conditions in detailed supernova models. We find that, for
equal total numbers of neutrons and protons (eta=0), Ti44 production is most
sensitive to the following reaction rates: Ti44(alpha,p)V47,
alpha(2alpha,gamma)C12, Ti44(alpha,gamma)Cr48, V45(p,gamma)Cr46. We tabulate
the most sensitive reactions in order of their importance to the Ti44
production near the standard values of currently accepted cross-sections, at
both reduced reaction rate (0.01X) and at increased reaction rate (100X)
relative to their standard values. Although most reactions retain their
importance for eta > 0, that of V45(p,gamma)Cr46 drops rapidly for eta >=
0.0004. Other reactions assume greater significance at greater neutron excess:
C12(alpha,gamma)O16, Ca40(alpha,gamma)Ti44, Al27(alpha,n)P30, Si30(alpha,n)S33.
Because many of these rates are unknown experimentally, our results suggest the
most important targets for future cross section measurements governing the
value of this observable abundance.Comment: 37 pages, LaTex, 17 figures, 8 table
Workplace Organization and Innovation
This study uses data on Canadian establishments to test whether particular organizational structures are correlated with the likelihood of adopting process and product innovations, controlling for the endogeneity of the predictors. We find that establishments with decentralized decision-making, information-sharing programs, or incentive pay plans are significantly more likely to innovate than other establishments. Larger establishments and those with a high vacancy rate are also more likely to innovate. These findings are consistent with a model in which workers hold information about production inefficiencies or consumer demands that can lead to productive innovations and that workplace organization attributes facilitate the communication and implementation of those ideas.Innovation, Decision-Making, Information-Sharing
AVIRIS data characteristics and their effects on spectral discrimination of rocks exposed in the Drum Mountains, Utah: Results of a preliminary study
Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) data collected over a geologically diverse field site and over a nearby calibration site were analyzed and interpreted in efforts to document radiometric and geometric characteristics of AVIRIS, quantify and correct for detrimental sensor phenomena, and evaluate the utility of AVIRIS data for discriminating rock types and identifying their constituent mineralogy. AVIRIS data acquired for these studies exhibit a variety of detrimental artifacts and have lower signal-to-noise ratios than expected in the longer wavelength bands. Artifacts are both inherent in the image data and introduced during ground processing, but most may be corrected by appropriate processing techniques. Poor signal-to-noise characteristics of this AVIRIS data set limited the usefulness of the data for lithologic discrimination and mineral identification. Various data calibration techniques, based on field-acquired spectral measurements, were applied to the AVIRIS data. Major absorption features of hydroxyl-bearing minerals were resolved in the spectra of the calibrated AVIRIS data, and the presence of hydroxyl-bearing minerals at the corresponding ground locations was confirmed by field data
Quantum lattice gases and their invariants
The one particle sector of the simplest one dimensional quantum lattice gas
automaton has been observed to simulate both the (relativistic) Dirac and
(nonrelativistic) Schroedinger equations, in different continuum limits. By
analyzing the discrete analogues of plane waves in this sector we find
conserved quantities corresponding to energy and momentum. We show that the
Klein paradox obtains so that in some regimes the model must be considered to
be relativistic and the negative energy modes interpreted as positive energy
modes of antiparticles. With a formally similar approach--the Bethe ansatz--we
find the evolution eigenfunctions in the two particle sector of the quantum
lattice gas automaton and conclude by discussing consequences of these
calculations and their extension to more particles, additional velocities, and
higher dimensions.Comment: 19 pages, plain TeX, 11 PostScript figures included with epsf.tex
(ignore the under/overfull \vbox error messages
Facilitated diffusion of proteins on chromatin
We present a theoretical model of facilitated diffusion of proteins in the
cell nucleus. This model, which takes into account the successive
binding/unbinding events of proteins to DNA, relies on a fractal description of
the chromatin which has been recently evidenced experimentally. Facilitated
diffusion is shown quantitatively to be favorable for a fast localization of a
target locus by a transcription factor, and even to enable the minimization of
the search time by tuning the affinity of the transcription factor with DNA.
This study shows the robustness of the facilitated diffusion mechanism, invoked
so far only for linear conformations of DNA.Comment: 4 pages, 4 figures, accepted versio
Operator *-correspondences in analysis and geometry
An operator *-algebra is a non-selfadjoint operator algebra with completely
isometric involution. We show that any operator *-algebra admits a faithful
representation on a Hilbert space in such a way that the involution coincides
with the operator adjoint up to conjugation by a symmetry. We introduce
operator *-correspondences as a general class of inner product modules over
operator *-algebras and prove a similar representation theorem for them. From
this we derive the existence of linking operator *-algebras for operator
*-correspondences. We illustrate the relevance of this class of inner product
modules by providing numerous examples arising from noncommutative geometry.Comment: 31 pages. This work originated from the MFO workshop "Operator spaces
and noncommutative geometry in interaction
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