1,008 research outputs found
Recombinant Charmonium in strongly coupled Quark-Gluon Plasma
We update our previous work of a Langevin-with-interaction model for
charmonium in heavy-ion collisions, by considering the effect due to
recombination. We determine the contribution to J/psi yields from
charm-anticharm pairs whose constituent quarks originate from two different
hard processes. Like the surviving J/psi states, the recombinant J/psi also
undergo both a stochastic interaction, determined by a hydrodynamical
simulation of the heavy-ion collision, and an interaction determined by the
heavy quark-antiquark potentials measured on the lattice for appropriate
temperatures. From the results of these simulations, we determine both the
direct and the recombinant contribution to the J/psi yields for RHIC
conditions, and find that for central collisions, between 30% and 50% of the
J/psi yield is due to recombinant production. We compare our results with other
models and look for how the recombinant contribution differs from the surviving
contribution in the differential p_t yields. Including the recombinant
contribution improves the agreement with the latest analysis of charmonium at
RHIC, which shows an absence of anomalous suppression except in the most
central collisions.Comment: 5 pages, 4 figure
Home Field Advantage: Sprint Sensitivity to Ecologically Relevant Substrates in Lizards
Effectively moving across variable substrates is important to all terrestrial animals. Much attention has been given to the effects of different substrates on locomotor performance in an attempt to link ecology and morphology. Sprint sensitivity is the decrease in sprint speed due to change in substrate. This study measures sprint sensitivity to substrate rugosity among six lizard species that occupy rocky, sandy, and/or semi-arboreal habitats. Lizards that use rocky habitats are less sensitive to changes in substrate rugosity, followed by arboreal lizards, and then by lizards that use sandy habitats. Phylogenetic analysis suggests that using rocks is highly correlated with decreased sprint sensitivity, long toes, and wide bodies. These results are discussed in the context of the adaptive significance of substrate selection, stability, and the evolution of sprint speed
Perceptions on Police Use of Force: A General Strain Theory Approach to Explicate Use of Force Incidents
This mixed method study focused on stress and its influence on police officers’ use of force. As a theoretical frame, Agnew’s General Strain Theory (GST) was applied to measure police officers’ decision making process in use of force, and the evaluation was compared to the college population. Data derived from law enforcement officers and college students via survey questionnaires reflecting strain factors and the Use of Force Model of case-vignettes. The magnitude of strain is measured via the assessment three major psychological diagnostic criteria: 1) STAI (State Trait Anxiety Inventory, 2) PTSD (Post-Traumatic Stress Disorder), and 3) DI (Depression Inventory). In comparison with the student population, law enforcement personnel responses to use of force vignettes were relatively consistent and responded with a lower level of force when paralleled with the Use of Force Model. The qualitative assessment were consistent with quantitative results emphasizing practical police training and education, which would minimize use of force issues. This study served its purpose as it reaffirms law enforcement as a stressful occupation, offers a direction to future research and proposes policy implications
A study of the potential effects of deepening the Corpus Christi Ship Channel on hurricane storm surge
publishedVersio
Economic Evaluation of Asset Ownership Transfer Methods and Family Farm Business Arrangements after the Tax Reform Act of 1976
Agricultural Economic
Trade Credit Policies and Receivables Management for the Fertilizer Industry
Agricultural Economic
Charmonium in strongly coupled quark-gluon plasma
The growing consensus that a strongly-coupled quark-gluon plasma (sQGP) has
been observed at the SPS and RHIC experiments suggests a different framework
for examining heavy quark dynamics. We present both semi-analytical treatment
of Fokker-Planck (FP) evolution in pedagogical examples and numerical Langevin
simulations of evolving charm quark-antiquark pairs on top of a
hydrodynamically expanding fireball. In this way, we may conclude that the
survival probability of bound charmonia states is greater than previously
estimated, as the spatial equilibration of pairs proceeds through a ``slowly
dissolving lump'' stage related to the pair interaction.Comment: 12 pages, 13 figure
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Dynamic compaction of tungsten carbide powder.
The shock compaction behavior of a tungsten carbide powder was investigated using a new experimental design for gas-gun experiments. This design allows the Hugoniot properties to be measured with reasonably good accuracy despite the inherent difficulties involved with distended powders. The experiments also provide the first reshock state for the compacted powder. Experiments were conducted at impact velocities of 245, 500, and 711 m/s. A steady shock wave was observed for some of the sample thicknesses, but the remainder were attenuated due to release from the back of the impactor or the edge of the sample. The shock velocity for the powder was found to be quite low, and the propagating shock waves were seen to be very dispersive. The Hugoniot density for the 711 m/s experiment was close to ambient crystal density for tungsten carbide, indicating nearly complete compaction. When compared with quasi-static compaction results for the same material, the dynamic compaction data is seen to be significantly stiffer for the regime over which they overlap. Based on these initial results, recommendations are made for improving the experimental technique and for future work to improve our understanding of powder compaction
An Overview of Operational Characteristics of Selected Irrigation Districts in the Texas Lower Rio Grande Valley: Delta Lake Irrigation District
Population expansion and water shortfalls have placed the Texas Lower Rio Grande Valley (Valley) center stage in water publicity. The unique characteristics and lack of public knowledge on how irrigation districts divert and convey water from the Rio Grande to municipal, industrial, and agriculture consumers have precipitated questions regarding the operations and makeup of these districts. Differences between and similarities across irrigation districts can be partially attributed to the topography, water-delivery infrastructure system, past financial decisions, and population demographics and clientele base of each irrigation district. Delta Lake Irrigation District (DLID) is one of the 29 irrigation districts in the Valley. This study presents an overview of DLID that includes a brief historical background, a description of the District, and discussion of the District’s current operations. Specific information in the report details how the District diverts and delivers its allocated water from the Rio Grande, how it is used (i.e., municipal, industry, and agriculture), and mechanisms for allocation within and outside the District.
The uniqueness of the Lower Rio Grande Valley irrigation districts requires an understanding of their origins and operating mannerisms to explain their overall institutional effects. Through unlocking some of the conundrum associated with these individual irrigation districts, policymakers and other interested stakeholders will have a better perception of the culture and evolution that surround these unique districts, thereby facilitating improved policy-making decisions affecting the region’s water supply and usage
An Overview of Operational Characteristics of Selected Irrigation Districts in the Texas Lower Rio Grande Valley: Harlingen Irrigation District Cameron County No. 1
Population expansion and water shortfalls have placed the Texas Lower Rio Grande Valley (Valley) center stage in water publicity. The unique characteristics and lack of public knowledge on how irrigation districts divert and convey water from the Rio Grande to municipal, industrial, and agricultural consumers have precipitated questions regarding the operations and makeup of these districts. Differences between and similarities across irrigation districts can be partially attributed to the topography, water-delivery infrastructure system, past financial decisions, and population demographics and clientele base of each irrigation district. Harlingen Irrigation District Cameron County No. 1 (HIDCC1) is one of the 29 irrigation districts in the Valley. This study presents an overview of HIDCC1 that includes a brief historical background, a description of the District, and discussion of the District’s current operations. Specific information in the report details how the District diverts and delivers its allocated water from the Rio Grande, how it is used (i.e., municipal, industry, and agriculture), and mechanisms for allocation within and outside the District.
The uniqueness of the Lower Rio Grande Valley irrigation districts requires an understanding of their origins and operating mannerisms to explain their overall institutional effects. Through unlocking some of the conundrum associated with these individual irrigation districts, policymakers and other interested stakeholders will have a better perception of the culture and evolution that surround these unique districts,thereby facilitating improved policy-making decisions affecting the region’s water supply and usage
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