545 research outputs found
Aspects of emergent geometry in the AdS/CFT context
We study aspects of emergent geometry for the case of orbifold superconformal
field theories in four dimensions, where the orbifolds are abelian within the
AdS/CFT proposal. In particular, we show that the realization of emergent
geometry starting from the N=4 SYM theory in terms of a gas of particles in the
moduli space of vacua of a single D3 brane in flat space gets generalized to a
gas of particles on the moduli space of the corresponding orbifold conformal
field theory (a gas of D3 branes on the orbifold space). Our main purpose is to
show that this can be analyzed using the same techniques as in the N=4 SYM case
by using the method of images, including the measure effects associated to the
volume of the gauge orbit of the configurations. This measure effect gives an
effective repulsion between the particles that makes them condense into a
non-trivial vacuum configuration, and it is exactly these configurations that
lead to the geometry of X in the AdS x X dual field theoryComment: 24 page
Variability in upwelling across the tropical tropopause and correlations with tracers in the lower stratosphere
Temporal variability of the upwelling near the tropical tropopause on daily to annual timescales is investigated using three different estimates computed from the ERA-Interim reanalysis. These include upwelling archived by the reanalysis, plus estimates derived from thermodynamic and momentum balance calculations. Substantial variability in upwelling is observed on both seasonal and sub-seasonal timescales, and the three estimates show reasonably good agreement. Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing the calculated upwelling estimates with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Statistically significant correlations between upwelling, temperatures and tracers are also found for sub-seasonal timescales, demonstrating the importance of upwelling in forcing transient variability in the lower tropical stratosphere
Work group inclusion : test of a scale and model
We develop a theoretically based 10-item measure of work group inclusion comprised of two components (belongingness and uniqueness) and use this measure to empirically test the nomological network of work group inclusion developed by Shore et al. In Phase 1, we use two samples of full-time employees to develop and refine items as well as establish content validity. In Phase 2, we demonstrate convergent, discriminant, and incremental validity with both conceptually related and unrelated constructs. In Phase 3, we use data from an additional sample of employees and supervisors to test criterion-related validity and mediation by examining the multilevel relationships between inclusion and important antecedents and outcomes. Across the three phases of our study, the results demonstrate support not only for the factor structure, reliability, and validity of our work group inclusion measure but also for a theoretical model in which the construct of inclusion has important implications for individuals and organizations
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Seasonal persistence of northern low- and middle-latitude anomalies of ozone and other trace gases in the upper stratosphere
Analysis of observed ozone profiles in Northern Hemisphere low and middle latitudes reveals the seasonal persistence of ozone anomalies in both the lower and upper stratosphere. Principal component analysis is used to detect that above 16 hPa the persistence is strongest in the latitude band 15–45°N, while below 16 hPa the strongest persistence is found over 45–60°N. In both cases, ozone anomalies persist through the entire year from November to October. The persistence of ozone anomalies in the lower stratosphere is presumably related to the wintertime ozone buildup with subsequent photochemical relaxation through summer, as previously found for total ozone. The persistence in the upper stratosphere is more surprising, given the short lifetime of Ox at these altitudes. It is hypothesized that this “seasonal memory” in the upper stratospheric ozone anomalies arises from the seasonal persistence of transport-induced wintertime NOy anomalies, which then perturb the ozone chemistry throughout the rest of the year. This hypothesis is confirmed by analysis of observations of NO2, NOx, and various long-lived trace gases in the upper stratosphere, which are found to exhibit the same seasonal persistence. Previous studies have attributed much of the year-to-year variability in wintertime extratropical upper stratospheric ozone to the Quasi-Biennial Oscillation (QBO) through transport-induced NOy (and hence NO2) anomalies but have not identified any statistical connection between the QBO and summertime ozone variability. Our results imply that through this “seasonal memory,” the QBO has an asynchronous effect on ozone in the low to midlatitude upper stratosphere during summer and early autumn
Inclusive leadership : realizing positive outcomes through belongingness and being valued for uniqueness
We introduce a theoretically-grounded conceptualization of inclusive leadership and present a framework for understanding factors that contribute to and follow from inclusive leadership within work groups. We conceptualize inclusive leadership as a set of positive leader behaviors that facilitate group members perceiving belongingness in the work group while maintaining their uniqueness within the group as they fully contribute to group processes and outcomes. We propose that leader pro-diversity beliefs, humility, and cognitive complexity increase the propensity of inclusive leader behaviors. We identify five categories of inclusive leadership behaviors that facilitate group members' perceptions of inclusion, which in turn lead to member work group identification, psychological empowerment, and behavioral outcomes (creativity, job performance, and reduced turnover) in the pursuit of group goals. This framework provides theoretical grounding for the construct of inclusive leadership while advancing our understanding of how leaders can increase diverse work group effectiveness
Relationships Between Physical Measurements and Calving Difficulty in Two-Year-Old Santa Gertrudis Heifers
Last updated: 6/1/200
Numerical tests of AdS/CFT at strong coupling
We study various correlation functions (two and three point functions) in a
large matrix model of six commuting matrices with a numerical Monte Carlo
algorithm. This is equivalent to a model of a gas of particles in six
dimensions with a confining quadratic potential and logarithmic repulsions at
finite temperature, where we are measuring the leading order non-gaussianities
in the thermal fluctuations.
This is a simplified model of the low energy dynamics of N=4 SYM at strong
coupling. We find strong evidence that the simplified matrix model matches with
the dual gravitational description of three point functions in the AdS/CFT
correspondence.Comment: 23 pages, 7 figures, revtex. v2: minor correction
DESCRIPTIVE ANALYSIS OF THE SMALL RUMINANT MEAT OFFERING IN PUERTO RICO
DESCRIPTIVE ANALYSIS OF THE SMALL RUMINANT MEAT OFFERING IN PUERTO RIC
Trajectory model simulations of ozone (O<sub>3</sub>) and carbon monoxide (CO) in the lower stratosphere
A domain-filling, forward trajectory model originally developed for
simulating stratospheric water vapor is used to simulate ozone (O3) and
carbon monoxide (CO) in the lower stratosphere. Trajectories are
initialized in the upper troposphere, and the circulation is based on
reanalysis wind fields. In addition, chemical production and loss rates
along trajectories are included using calculations from the Whole Atmosphere
Community Climate Model (WACCM). The trajectory model results show good
overall agreement with satellite observations from the Aura Microwave Limb
Sounder (MLS) and the Atmospheric Chemistry Experiment Fourier Transform
Spectrometer (ACE-FTS) in terms of spatial structure and seasonal
variability. The trajectory model results also agree well with the Eulerian
WACCM simulations. Analysis of the simulated tracers shows that seasonal
variations in tropical upwelling exerts strong influence on O3 and CO
in the tropical lower stratosphere, and the coupled seasonal cycles provide
a useful test of the transport simulations. Interannual variations in the
tracers are also closely coupled to changes in upwelling, and the trajectory
model can accurately capture and explain observed changes during 2005–2011.
This demonstrates the importance of variability in tropical upwelling in
forcing chemical changes in the tropical lower stratosphere
Ozone and Tracer Transport Variations in the Summer Northern Hemisphere Stratosphere
Constituent observations from the Upper Atmosphere Research Satellite (UARS) in combination with estimates of the residual circulation are used to examine the transport and chemical budgets of HF, CH4 and O3 in the summer Northern Hemisphere. Budget calculations of HF, CH4 and O3 show that the transport tendency due to the residual circulation increases in magnitude and is largely opposed by eddy motions through the summer months. Ozone budget analyses show that between 100 and 31 hPa, the magnitudes of the mean circulation and eddy transport terms increase through the summer months, producing tendencies that are factors of 2 to 3 times larger than the observed ozone change in the stratosphere. Chemical loss dominates the observed ozone decrease only at the highest latitudes, poleward of about 70°N. A comparison of observations from the Total Ozone Mapping Spectrometer with UARS-calculated total ozone suggests that poleward of 50°N, between 35% and 55% of the seasonal ozone decline during the summer occurs at altitudes below 100 hPa. The overall uncertainties, associated primarily with calculations of the residual circulation and eddy transport, are relatively large, and thus prevent accurate and useful constraints on the ozone chemical rate in the lower stratosphere
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