1,699 research outputs found
The Employment, Earnings, and Income of Less-Skilled Workers over the Business Cycle
In this paper, I examine the effect of business cycles on the employment, earnings, and income of persons in different demographic groups. I classify individuals by sex, education, and race. The analysis uses data from the Current Population Survey’s Outgoing Rotation Group data, covering the period 1979–1992, and March Annual Demographic File data, covering the period 1975–1997. Many different individual and family outcome measures are considered, including employment to population ratios, weekly earnings, hourly earnings, annual hours, annual earnings, family earnings, family transfer income, and total family income. The regression model is specified such that the key parameters measure how the labor market outcomes of less-skilled workers vary with the business cycle relative to the variability for high-skill groups. The analysis uses variation across MSAs in the timing and severity of shocks. The results consistently show that individuals with lower educational levels, nonwhites, and low-skill women experience greater cyclical fluctuation than high-skill men. These results are the most striking when examining comprehensive measures of labor force activity such as the likelihood of full-time, full-year work. Government transfers and the earnings of other family members decrease the differences between groups, resulting in more skill-group-neutral effects of business cycles on family income than on individual earnings. The paper examines the stability of these results by comparing evidence across the 1982 and 1992 recessions. The evidence suggests that the 1992 recession led to more uniform effects across skill groups than did earlier cycles.
A detailed determination of the a priori mixing angles in non-leptonic decays of hyperons
Non-leptonic Decays of Hyperons can provide a detailed determination of the a
priori mixing angles that appear in physical hadrons in the approach in which
non-perturbative flavor and parity violations are present in tiny pieces of the
hadron mass operator. The determination of such angles in these decays will
provide a bench mark to test their necessary universality-like property in
other types of decays. Our main result is that the magnitudes of the a priori
mixing angles can be determined quite accurately
Gluon mass generation in the PT-BFM scheme
In this article we study the general structure and special properties of the
Schwinger-Dyson equation for the gluon propagator constructed with the pinch
technique, together with the question of how to obtain infrared finite
solutions, associated with the generation of an effective gluon mass.
Exploiting the known all-order correspondence between the pinch technique and
the background field method, we demonstrate that, contrary to the standard
formulation, the non-perturbative gluon self-energy is transverse
order-by-order in the dressed loop expansion, and separately for gluonic and
ghost contributions. We next present a comprehensive review of several subtle
issues relevant to the search of infrared finite solutions, paying particular
attention to the role of the seagull graph in enforcing transversality, the
necessity of introducing massless poles in the three-gluon vertex, and the
incorporation of the correct renormalization group properties. In addition, we
present a method for regulating the seagull-type contributions based on
dimensional regularization; its applicability depends crucially on the
asymptotic behavior of the solutions in the deep ultraviolet, and in particular
on the anomalous dimension of the dynamically generated gluon mass. A
linearized version of the truncated Schwinger-Dyson equation is derived, using
a vertex that satisfies the required Ward identity and contains massless poles
belonging to different Lorentz structures. The resulting integral equation is
then solved numerically, the infrared and ultraviolet properties of the
obtained solutions are examined in detail, and the allowed range for the
effective gluon mass is determined. Various open questions and possible
connections with different approaches in the literature are discussed.Comment: 54 pages, 24 figure
Linear Collider Capabilities for Supersymmetry in Dark Matter Allowed Regions of the mSUGRA Model
Recent comparisons of minimal supergravity (mSUGRA) model predictions with
WMAP measurements of the neutralino relic density point to preferred regions of
model parameter space. We investigate the reach of linear colliders (LC) with
and 1 TeV for SUSY in the framework of the mSUGRA model. We find
that LCs can cover the entire stau co-annihilation region provided \tan\beta
\alt 30. In the hyperbolic branch/focus point (HB/FP) region of parameter
space, specialized cuts are suggested to increase the reach in this important
``dark matter allowed'' area. In the case of the HB/FP region, the reach of a
LC extends well past the reach of the CERN LHC. We examine a case study in the
HB/FP region, and show that the MSSM parameters and can be
sufficiently well-measured to demonstrate that one would indeed be in the HB/FP
region, where the lightest chargino and neutralino have a substantial higgsino
component.Comment: 29 pages, 15 EPS figures; updated version slightly modified to
conform with published versio
Monte Carlo Exploration of Warped Higgsless Models
We have performed a detailed Monte Carlo exploration of the parameter space
for a warped Higgsless model of electroweak symmetry breaking in 5 dimensions.
This model is based on the gauge group
in an AdS bulk with arbitrary gauge kinetic terms on both the Planck and
TeV branes. Constraints arising from precision electroweak measurements and
collider data are found to be relatively easy to satisfy. We show, however,
that the additional requirement of perturbative unitarity up to the cut-off,
TeV, in elastic scattering in the absence of dangerous
tachyons eliminates all models. If successful models of this class exist, they
must be highly fine-tuned.Comment: 26 pages, 7 figures; new fig and additional text adde
Work-Related Mental Health and Job Performance: Can Mindfulness Help?
Work-related mental health issues such as work-related stress and addiction to work impose a significant health and economic burden to the employee, the employing organization, and the country of work more generally. Interventions that can be empirically shown to improve levels of work-related mental health – especially those with the potential to concurrently improve employee levels of work performance – are of particular interest to occupational stakeholders. One such broad-application interventional approach currently of interest to occupational stakeholders in this respect is mindfulness-based interventions (MBIs). Following a brief explication of the mindfulness construct, this paper critically discusses current research directions in the utilization of mindfulness in workplace settings and assesses its suitability for operationalization as an organization-level work-related mental health intervention. By effecting a perceptual-shift in the mode of responding and relating to sensory and cognitive-affective stimuli, employees that undergo mindfulness training may be able to transfer the locus of control for stress from external work conditions to internal metacognitive and attentional resources. Therefore, MBIs may constitute cost-effective organization-level interventions due to not actually requiring any modifications to human resource management systems and practises. Based on preliminary empirical findings and on the outcomes of MBI studies with clinical populations, it is concluded that MBIs appear to be viable interventional options for organizations wishing to improve the mental health of their employees
Lower limit on the neutralino mass in the general MSSM
We discuss constraints on SUSY models with non-unified gaugino masses and R_P
conservation. We derive a lower bound on the neutralino mass combining the
direct limits from LEP, the indirect limits from gmuon, bsgamma, Bsmumu and the
relic density constraint from WMAP. The lightest neutralino (mneutralino=6GeV)
is found in models with a light pseudoscalar with MA<200GeV and a large value
for . Models with heavy pseudoscalars lead to mneutralino>18(29)GeV
for . We show that even a very conservative bound from the
muon anomalous magnetic moment can increase the lower bound on the neutralino
mass in models with mu<0 and/or large values of . We then examine
the potential of the Tevatron and the direct detection experiments to probe the
SUSY models with the lightest neutralinos allowed in the context of light
pseudoscalars with high . We also examine the potential of an e+e-
collider of 500GeV to produce SUSY particles in all models with neutralinos
lighter than the W. In contrast to the mSUGRA models, observation of at least
one sparticle is not always guaranteed.Comment: 37 pages, LateX, 16 figures, paper with higher resolution figures
available at
http://wwwlapp.in2p3.fr/~boudjema/papers/bound-lsp/bound-lsp.htm
Vortices, Instantons and Branes
The purpose of this paper is to describe a relationship between the moduli
space of vortices and the moduli space of instantons. We study charge k
vortices in U(N) Yang-Mills-Higgs theories and show that the moduli space is
isomorphic to a special Lagrangian submanifold of the moduli space of k
instantons in non-commutative U(N) Yang-Mills theories. This submanifold is the
fixed point set of a U(1) action on the instanton moduli space which rotates
the instantons in a plane. To derive this relationship, we present a D-brane
construction in which the dynamics of vortices is described by the Higgs branch
of a U(k) gauge theory with 4 supercharges which is a truncation of the
familiar ADHM gauge theory. We further describe a moduli space construction for
semi-local vortices, lumps in the CP(N) and Grassmannian sigma-models, and
vortices on the non-commutative plane. We argue that this relationship between
vortices and instantons underlies many of the quantitative similarities shared
by quantum field theories in two and four dimensions.Comment: 32 Pages, 4 Figure
A Prospective Study of the Association of Metacognitive Beliefs and Processes with Persistent Emotional Distress After Diagnosis of Cancer
Two hundred and six patients, diagnosed with primary breast or prostate cancer completed self-report questionnaires on two occasions: before treatment (T1) and 12 months later (T2). The questionnaires included: the Hospital Anxiety and Depression Scale; Impact of Events Scale; the Metacognitions Questionnaire-30 (MCQ-30) and the Illness Perceptions Questionnaire-revised. A series of regression analyses indicated that metacognitive beliefs at T1 predicted between 14 and 19 % of the variance in symptoms of anxiety, depression and trauma at T2 after controlling for age and gender. For all three outcomes, the MCQ-30 subscale ‘negative beliefs about worry’ made the largest individual contribution with ‘cognitive confidence’ also contributing in each case. For anxiety, a third metacognitive variable, ‘positive beliefs about worry’ also predicted variance in T2 symptoms. In addition, hierarchical analyses indicated that metacognitive beliefs explained a small but significant amount of variance in T2 anxiety (2 %) and T2 depression (4 %) over and above that explained by demographic variables, T1 symptoms and T1 illness perceptions. The findings suggest that modifying metacognitive beliefs and processes has the potential to alleviate distress associated with cancer
Genetic and environmental transactions underlying the associationbetween physical fitness/physical exercise and body composition
We examined mean effects and variance moderating effects of measures of physical activity and fitness on six measures of adiposity and their reciprocal effects in a subsample of the population-representative Danish Twin Registry. Consistent with prior studies, higher levels of physical activity suppressed variance in adiposity, but this study provided further insight. Variance suppression appeared to have both genetic and environmental pathways. Some mean effects appeared due to reciprocal influences of environmental circumstances differing among families but not between co-twins, suggesting these reciprocal effects are uniform. Some variance moderating effects also appeared due to biases in individual measures of adiposity, as well as to differences and inaccuracies in measures of physical activity. This suggests a need to avoid reliance on single measures of both physical activity and adiposity in attempting to understand the pathways involved in their linkages, and constraint in interpreting results if only single measures are available. Future research indications include identifying which physical activity-related environmental circumstances have relatively uniform effects on adiposity in everyone, and which should be individually tailored to maximize motivation to continue involvement.</p
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