1,751 research outputs found
A doubled discretisation of abelian Chern-Simons theory
A new discretisation of a doubled, i.e. BF, version of the pure abelian
Chern-Simons theory is presented. It reproduces the continuum expressions for
the topological quantities of interest in the theory, namely the partition
function and correlation function of Wilson loops. Similarities with free
spinor field theory are discussed which are of interest in connection with
lattice fermion doubling.Comment: 5 pages, revtex, 2 ps figures (epsf required). To appear in
Phys.Rev.Let
The Role of Protective Behavioral Strategies, Social Environment, and Housing Type on Heavy Drinking among College Students
Background: Though research has examined heavy drinking by housing type, the link between type of college student housing and protective behavioral strategies (PBS) has rarely been examined comparing different college campuses. Objectives: The purpose of this study is to examine the role of housing type, perceptions of peer drinking, and PBS with respondent heavy drinking among undergraduate college students from one Southeastern and one Midwestern university in the United States. Methods: 1,448 college students enrolled in undergraduate courses at two public universities completed a paper and pencil survey of attitudes and experiences about dating, sexuality, and substance use. Data were analyzed using multiple group path analysis. Results: Students living in Greek housing perceived their close friends as engaging in more risky drinking and had higher rates of heavy drinking compared to those living in other housing types. The effect of perceptions of peer drinking on PBS was significantly different between campuses, as were several other indirect pathways to heavy drinking. Conclusion/Importance: Understanding more about the differing roles of college residential environments can help inform effective drinking interventions and reduce heavy drinking among college students
A geometric discretisation scheme applied to the Abelian Chern-Simons theory
We give a detailed general description of a recent geometrical discretisation
scheme and illustrate, by explicit numerical calculation, the scheme's ability
to capture topological features. The scheme is applied to the Abelian
Chern-Simons theory and leads, after a necessary field doubling, to an
expression for the discrete partition function in terms of untwisted
Reidemeister torsion and of various triangulation dependent factors. The
discrete partition function is evaluated computationally for various
triangulations of and of lens spaces. The results confirm that the
discretisation scheme is triangulation independent and coincides with the
continuum partition functionComment: 27 pages, 5 figures, 6 tables. in late
Applicability of Monte Carlo Glauber models to relativistic heavy ion collision data
The accuracy of Monte Carlo Glauber model descriptions of minimum-bias
multiplicity frequency distributions is evaluated using data from the
Relativistic Heavy Ion Collider (RHIC) within the context of a sensitive,
power-law representation introduced previously by Trainor and Prindle (TP).
Uncertainties in the Glauber model input and in the mid-rapidity multiplicity
frequency distribution data are reviewed and estimated using the TP centrality
methodology. The resulting errors in model-dependent geometrical quantities
used to characterize heavy ion collisions ({\em i.e.} impact parameter, number
of nucleon participants , number of binary interactions ,
and average number of binary collisions per incident participant nucleon )
are presented for minimum-bias Au-Au collisions at = 20, 62,
130 and 200 GeV and Cu-Cu collisions at = 62 and 200 GeV.
Considerable improvement in the accuracy of collision geometry quantities is
obtained compared to previous Monte Carlo Glauber model studies, confirming the
TP conclusions. The present analysis provides a comprehensive list of the
sources of uncertainty and the resulting errors in the above geometrical
collision quantities as functions of centrality. The capability of energy
deposition data from trigger detectors to enable further improvements in the
accuracy of collision geometry quantities is also discussed.Comment: 27 pages, 4 figures, 11 table
Gauge-fixing, semiclassical approximation and potentials for graded Chern-Simons theories
We perform the Batalin-Vilkovisky analysis of gauge-fixing for graded
Chern-Simons theories. Upon constructing an appropriate gauge-fixing fermion,
we implement a Landau-type constraint, finding a simple form of the gauge-fixed
action. This allows us to extract the associated Feynman rules taking into
account the role of ghosts and antighosts. Our gauge-fixing procedure allows
for zero-modes, hence is not limited to the acyclic case. We also discuss the
semiclassical approximation and the effective potential for massless modes,
thereby justifying some of our previous constructions in the Batalin-Vilkovisky
approach.Comment: 46 pages, 4 figure
The Sum over Topologies in Three-Dimensional Euclidean Quantum Gravity
In Hawking's Euclidean path integral approach to quantum gravity, the
partition function is computed by summing contributions from all possible
topologies. The behavior such a sum can be estimated in three spacetime
dimensions in the limit of small cosmological constant. The sum over topologies
diverges for either sign of , but for dramatically different reasons:
for , the divergent behavior comes from the contributions of very
low volume, topologically complex manifolds, while for it is a
consequence of the existence of infinite sequences of relatively high volume
manifolds with converging geometries. Possible implications for
four-dimensional quantum gravity are discussed.Comment: 12 pages (LaTeX), UCD-92-1
Massage Gun Use at a Lower Frequency Does Not Alter Blood Flow
Data has shown that whole body vibration can affect blood flow velocity in arteries and improves cutaneous blood flow. However, there is very limited information available on therapeutic localized vibration. Massage guns have become very popular with little to no research validating their efficacy. It is currently unknown if massages guns can affect arterial blood flow. PURPOSE: To determine if massage gun treatment at 30Hz improves and retains blood flow in the popliteal artery as compared to a control condition. METHODS: There were 12 participants in this study (8 males and 4 females). The mean age was 22.7±1.6 yrs, the mean height was 181.1± 11.8 cm, and the mean weight was 78.2±16.2 kg. Participants wore shorts that allowed us to access their popliteal artery using ultrasound imaging. Participants wore electrodes to control the measurement of blood flow from widest artery diameter. Participants lay prone with a foam roller under their ankles to slightly elevate their feet. After ten minutes of rest, ultrasound imaging was used to find the participant’s popliteal artery behind the knee and took two baseline measurements. We measured the mean velocity of blood flow (TAmean) and volume flow (VolF). We measured subjects on 4 different days (30Hz at 5 minutes, 30Hz 10 minutes, Control 5 minutes, Control 10 minutes). Measurements of TAmean and VolF were measured at multiple time points after treatment. RESULTS: A two-factor repeated measures analysis was performed. Each subject was measured under all levels of condition (1=30hz 5 min, 4=Control 5 mi, 5=30hz 10 min, 8=Control 10 min) and time (baseline, post, post1-5, 7, 9, 11, 13, 15, 17, 19). TA mean is significantly greater in 30Hz versus control (p=0.0349). TAmean varies across time, and the effect of the condition on TAmean is related to time (p=0.0104). There is not a significant difference in flow between 30Hz and control (p=0.2425). Blood flow varies across time (pCONCLUSION: Use of a massage gun at a lower frequency setting of 30Hz may cause slight increases in velocity but does not increase mean blood flow as compared to control. Lower frequency settings on massage guns may not be benefit blood flow in the massaged muscle group
Stress‐response balance drives the evolution of a network module and its host genome
Stress response genes and their regulators form networks that underlie drug resistance. These networks often have an inherent tradeoff: their expression is costly in the absence of stress, but beneficial in stress. They can quickly emerge in the genomes of infectious microbes and cancer cells, protecting them from treatment. Yet, the evolution of stress resistance networks is not well understood. Here, we use a two‐component synthetic gene circuit integrated into the budding yeast genome to model experimentally the adaptation of a stress response module and its host genome in three different scenarios. In agreement with computational predictions, we find that: (i) intra‐module mutations target and eliminate the module if it confers only cost without any benefit to the cell; (ii) intra‐ and extra‐module mutations jointly activate the module if it is potentially beneficial and confers no cost; and (iii) a few specific mutations repeatedly fine‐tune the module's noisy response if it has excessive costs and/or insufficient benefits. Overall, these findings reveal how the timing and mechanisms of stress response network evolution depend on the environment
A comparative study of the four-ball cylinder test, the Jackson cross-cylinder test, and the near cylinder
A comparative study of the four-ball cylinder test, the Jackson cross-cylinder test, and the near cylinde
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