1,017 research outputs found
Phase separation in quasi incompressible fluids: Cahn-Hilliard model in the Cattaneo-Maxwell framework
In this paper we propose a mathematical model of phase separation for a
quasi-incompressible binary mixture where the spinodal decomposition is induced
by an heat flux governed by the Cattaneo-Maxwell equation. As usual, the phase
separation is considered in the framework of phase field modeling so that the
transition is described by an additional field, the concentration c. The
evolution of concentration is described by the Cahn-Hilliard equation and in
our model is coupled with the Navier-Stokes equation. Since thermal effect are
included, the whole set of evolution equations is set up for the velocity, the
concentration, the temperature and the heat flux. The model is compatible with
thermodynamics and a maximum theorem holds.Comment: Submitted to ZAM
Exact beta function from the holographic loop equation of large-N QCD_4
We construct and study a previously defined quantum holographic effective
action whose critical equation implies the holographic loop equation of large-N
QCD_4 for planar self-avoiding loops in a certain regularization scheme. We
extract from the effective action the exact beta function in the given scheme.
For the Wilsonean coupling constant the beta function is exacly one loop and
the first coefficient agrees with its value in perturbation theory. For the
canonical coupling constant the exact beta function has a NSVZ form and the
first two coefficients agree with their value in perturbation theory.Comment: 42 pages, latex. The exponent of the Vandermonde determinant in the
quantum effective action has been changed, because it has been employed a
holomorphic rather than a hermitean resolution of identity in the functional
integral. Beta function unchanged. New explanations and references added,
typos correcte
Two dimensional QCD and abelian bosonization
A bosonized action, that reproduces the structure of the 't Hooft equation
for in the large- limit, up to regularization dependent terms, is
derived.Comment: paper revised, several signs and coefficients corrected. A comment on
regularization dependence and several references adde
Splenic Embolization Decreases Infectious Complications and Resource Utilization Compared to Splenectomy in Severely Injured Patients
Introduction. Increasing use of main coil angioembolization for splenic injury has raised concerns of increased complication rates and resource utilization compared to splenectomy. This study examined complication rates for severely injured patients undergoing splenectomy versus main coil angioembolization. Methods. Demographic data (age, sex, and race), Injury Severity Score (ISS), and splenic injury grade were collected prospectively on all patients admitted to the intensive care unit with blunt splenic injury treated with splenectomy or main coil angioembolization. Outcome measures (transfusion requirements, mechanical ventilation use and duration, mortality, intensive care unit and hospital length of stay, infection rate, and systemic inflammatory response syndrome or SIRS score) were reviewed daily. Results. Of 116 patients reviewed, 65 underwent splenectomy and 51 underwent main coil angioembolization. Groups were comparable for age, sex, race, and mechanism of injury. Splenectomized patients had a higher ISS (41 vs 31) and splenic injury grade (3.7 vs 3.2). The main coil angioembolization group had a lower transfusion requirement, hospital length of stay, incidence of mechanical ventilation, nosocomial infection rate, and SIRS score. Overall, mortality and ventilator days were lower but not statistically significant. Conclusions. Severely injured patients treated with splenectomy had significantly higher infection rates and resource utilization compared to those treated with main coil angioembolization
Gauge theories in anti-selfdual variables
Some years ago the Nicolai map, viewed as a change of variables from the
gauge connection in a fixed gauge to the anti-selfdual part of the curvature,
has been extended by the first named author to pure YM from its original
definition in N=1 SUSY YM. We study here the perturbative 1PI effective action
in the anti-selfdual variables of any gauge theory, in particular pure YM, QCD
and N=1 SUSY YM. We prove that the one-loop 1PI effective action of a gauge
theory mapped to the anti-selfdual variables in any gauge is identical to the
one of the original theory. This is due to the conspiracy between the Jacobian
of the change to the anti-selfdual variables and an extra functional
determinant that arises from the non-linearity of the coupling of the
anti-selfdual curvature to an external source in the Legendre transform that
defines the 1PI effective action. Hence we establish the one-loop perturbative
equivalence of the mapped and original theories on the basis of the identity of
the one-loop 1PI effective actions. Besides, we argue that the identity of the
perturbative 1PI effective actions extends order by order in perturbation
theory.Comment: 19 pages; paper shortened and sharpened according to the referee
suggestion
An Examination of the Influence of Band Director Teaching Style and Personality on Ratings at Concert and Marching Band Events
This descriptive correlational study examined the relationship between high school band directors\u27 teaching style and personality and their ratings in marching and concert band festivals using the Five-Factor Model of personality and Gumm\u27s Music Teaching Style Inventory. The sample (N=176) consisted of 46% of all high school band directors in Florida. Criterion variables included marching and concert festival ratings, state concert band ratings, Florida Marching Band Coalition marching competition scores, frequency of attendance of these last two events, and the balance between marching and concert band. Predictor variables included thirty personality facets and eight teaching styles. Four demographic variables included gender, experience, academic degree, and primary instrument.
One predictor, Time Efficiency, stood out as having particularly strong correlations with all of criterion variables. Regression models produced the following findings: 23% of the variation in concert band ratings can be explained from Time Efficiency, Immoderation, Music Concept Learning Assertiveness, and Nonverbal Motivation; 22% of the variation in marching band scores can be explained by Time Efficiency, Music Concept Learning, Imagination, Modesty, Cheerfulness, and Anxiety; 20% of the variation in participation in state Florida Bandmasters Association concert band festival participation can be explained by Time Efficiency, Positive Learning Environment, Immoderation, Music Concept Learning, Group Dynamic, and Assertive Teaching, and 11% of the variation in FMBC competitive marching band event attendance can be explained by Time Efficiency, Nonverbal Motivation, Dutifulness, and Modesty. Most subjects (84.3%) were balanced, while the remaining 15.7% were marching oriented. There was no significant difference in marching ratings between groups, although balanced subjects scored significantly higher in concert band and attended significantly fewer marching competitions. A discriminant function selected four predictor variables with a significant effect: Assertiveness, Immoderation, Adventurousness, and Emotion (Wilks\u27 λ = .84, χ2 = 23.42, df = 4, p less than .001) which was able to successfully predict group membership 72.3% of the time.
Recommendations include emphasizing the concert band as the core and playing concert music all year. Directors may benefit from being cognizant of their personalities and teaching styles which may enable them to modify their behavior and practices when appropriate to be more effective teachers
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