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Articles 1 - 12 of 12

Full-Text Articles in Physical Sciences and Mathematics

Constraints On Vector Unparticle Physics From Cosmic Censorship, Jonas R. Mureika Oct 2011

Constraints On Vector Unparticle Physics From Cosmic Censorship, Jonas R. Mureika

Physics Faculty Works

Vector unparticle couplings to standard model fields produce repulsive corrections to gravity. From a general relativistic perspective, this leads to an effective Reissner-Nordstrom-like metric whose "charge" is a function of the unparticle coupling constant λ, and therefore can admit naked singularities. Requiring the system to respect cosmic censorship provides a new method of constraining the value of λ. These limits are extremely loose for stellar-mass black holes, but commensurate with existing bounds for primordial black holes. In the case of theoretical low-mass black holes, the bounds on λ are much stricter than those derived from astrophysical and accelerator …


(1+1)-Dimensional Entropic Gravity, R. B. Mann, Jonas R. Mureika Sep 2011

(1+1)-Dimensional Entropic Gravity, R. B. Mann, Jonas R. Mureika

Physics Faculty Works

We consider the formulation of entropic gravity in two spacetime dimensions. The usual gravitational force law is derived even in the absence of area, as normally required by the holographic principle. A special feature of this perspective concerns the nature of temperature and entropy defined at a point. We argue that the constancy of the gravitational force in one spatial dimension implies the information contained at each point in space is an internal degree of freedom on the manifold, and furthermore is a universal constant, contrary to previous assertions that entropic gravity in one spatial dimension is ill-defined. We give …


Photochemical Modeling Of Glyoxal At A Rural Site: Observations And Analysis From Bearpex 2007, Nicole Bouvier-Brown Sep 2011

Photochemical Modeling Of Glyoxal At A Rural Site: Observations And Analysis From Bearpex 2007, Nicole Bouvier-Brown

Chemistry and Biochemistry Faculty Works

We present roughly one month of high time-resolution, direct, in situ measurements of gas-phase glyoxal acquired during the BEARPEX 2007 field campaign. The research site, located on a ponderosa pine plantation in the Sierra Nevada mountains, is strongly influenced by biogenic volatile organic compounds (BVOCs); thus this data adds to the few existing measurements of glyoxal in BVOC-dominated areas. The short lifetime of glyoxal of ~1 h, the fact that glyoxal mixing ratios are much higher during high temperature periods, and the results of a photochemical model demonstrate that glyoxal is strongly influenced by BVOC precursors during high temperature periods. …


The Effects Of 24 Weeks Of Resistance Training With Simultaneous Elastic And Free Weight Loading On Muscular Performance Of Novice Lifters, Robert Rovetti Sep 2011

The Effects Of 24 Weeks Of Resistance Training With Simultaneous Elastic And Free Weight Loading On Muscular Performance Of Novice Lifters, Robert Rovetti

Mathematics Faculty Works

The purpose of this investigation was to assess the effectiveness of variable resistance as provided through elastic plus free weight techniques in college aged males and females. Twenty novice lifters were randomly assigned to a traditional free weight only (6 males and 5 females) or elastic band plus free weight group (5 males and 5 females) and 9 more normally active controls (5 males and 4 females), were recruited to maintain normal activity for the duration of the study. No differences existed between control, free weight and elastic band at baseline for age, body height, body mass, body mass index, …


Aspects Of Noncommutative (1+1)-Dimensional Black Holes, Jonas R. Mureika, Piero Nicolini Aug 2011

Aspects Of Noncommutative (1+1)-Dimensional Black Holes, Jonas R. Mureika, Piero Nicolini

Physics Faculty Works

We present a comprehensive analysis of the spacetime structure and thermodynamics of ( 1 + 1 )-dimensional black holes in a noncommutative framework. It is shown that a wider variety of solutions are possible than the commutative case considered previously in the literature. As expected, the introduction of a minimal length √ θ cures singularity pathologies that plague the standard two-dimensional general relativistic case, where the latter solution is recovered at large length scales. Depending on the choice of input parameters (black hole mass M, cosmological constant Λ , etc.), black hole solutions with zero, up to six, horizons …


Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy, Jonas R. Mureika, Dejan Stojkovic Mar 2011

Detecting Vanishing Dimensions Via Primordial Gravitational Wave Astronomy, Jonas R. Mureika, Dejan Stojkovic

Physics Faculty Works

Lower dimensionality at higher energies has manifold theoretical advantages as recently pointed out by Anchordoqui et al. [arXiv:1003.5914]. Moreover, it appears that experimental evidence may already exist for it: A statistically significant planar alignment of events with energies higher than TeV has been observed in some earlier cosmic ray experiments. We propose a robust and independent test for this new paradigm. Since ( 2 + 1 )-dimensional spacetimes have no gravitational degrees of freedom, gravity waves cannot be produced in that epoch. This places a universal maximum frequency at which primordial waves can propagate, marked by the transition between dimensions. …


Kinematical Conformal Cosmology: Fundamental Parameters From Astrophysical Observations, Gabriele U. Varieschi Jan 2011

Kinematical Conformal Cosmology: Fundamental Parameters From Astrophysical Observations, Gabriele U. Varieschi

Physics Faculty Works

No abstract provided.


The Chemistry Of Atmosphere-Forest Exchange (Cafe) Model-Part 2: Application To Bearpex-2007 Observations, Nicole C. Bouvier-Brown Jan 2011

The Chemistry Of Atmosphere-Forest Exchange (Cafe) Model-Part 2: Application To Bearpex-2007 Observations, Nicole C. Bouvier-Brown

Chemistry and Biochemistry Faculty Works

In a companion paper, we introduced the Chemistry of Atmosphere-Forest Exchange (CAFE) model, a vertically-resolved 1-D chemical transport model designed to probe the details of near-surface reactive gas exchange. Here, we apply CAFE to noontime observations from the 2007 Biosphere Effects on Aerosols and Photochemistry Experiment (BEARPEX-2007). In this work we evaluate the CAFE modeling approach, demonstrate the significance of in-canopy chemistry for forest-atmosphere exchange and identify key shortcomings in the current understanding of intra-canopy processes.

CAFE generally reproduces BEARPEX-2007 observations but requires an enhanced radical recycling mechanism to overcome a factor of 6 underestimate of hydroxyl (OH) concentrations observed …


Complete Graphs Whose Topological Symmetry Groups Are Polyhedral, Eric Flapan, Blake Mellor, Ramin Naimi Jan 2011

Complete Graphs Whose Topological Symmetry Groups Are Polyhedral, Eric Flapan, Blake Mellor, Ramin Naimi

Mathematics Faculty Works

We determine for which m the complete graph Km has an embedding in S3 whose topological symmetry group is isomorphic to one of the polyhedral groups A4, A5 or S4.


Robustness, Weak Stability, And Stability In Distribution Of Adaptive Filteringalgorithms Under Model Mismatch, Ben G. Fitzpatrick, G. Yin, Le Yi Wang Jan 2011

Robustness, Weak Stability, And Stability In Distribution Of Adaptive Filteringalgorithms Under Model Mismatch, Ben G. Fitzpatrick, G. Yin, Le Yi Wang

Mathematics Faculty Works

This work is concerned with robustness, convergence, and stability of adaptive filtering (AF) type algorithms in the presence of model mismatch. The algorithms under consideration are recursive and have inherent multiscale structure. They can be considered as dynamic systems, in which the `state' changes much more slowly than the perturbing noise. Beyond the existing results on adaptive algorithms, model mismatch significantly affects convergence properties of AF algorithms, raising issues of algorithm robustness. Weak convergence and weak stability (i.e., recurrence) under model mismatch are derived. Based on the limiting stochastic differential equations of suitably scaled iterates, stability in distribution is established. …


Finitely 1-Convex F-Rings, Suzanne Larson Jan 2011

Finitely 1-Convex F-Rings, Suzanne Larson

Mathematics Faculty Works

This paper investigates f-rings that can be constructed in a finite number of steps where every step consists of taking the fibre product of two f-rings, both being either a 1-convex f-ring or a fibre product obtained in an earlier step of the construction. These are the f-rings that satisfy the algebraic property that rings of continuous functions possess when the underlying topological space is finitely an F-space (i.e. has a Stone-čech compactification that is a finite union of compact F-spaces). These f-rings are shown to be SV f-rings with bounded inversion and finite rank and, when constructed from semisimple …


Heavy Episodic Drinking On College Campuses: Does Changing The Legal Drinking Age Make A Difference?, Jawaid W. Rasul, Robert G. Rommel, Geoffrey M. Jacquez, Ben G. Fitzpatrick, Azmy S. Ackleh, Neal Simonsen, Richard Scribner Jan 2011

Heavy Episodic Drinking On College Campuses: Does Changing The Legal Drinking Age Make A Difference?, Jawaid W. Rasul, Robert G. Rommel, Geoffrey M. Jacquez, Ben G. Fitzpatrick, Azmy S. Ackleh, Neal Simonsen, Richard Scribner

Mathematics Faculty Works

This article extends the compartmental model previously developed by Scribner et al. in the context of college drinking to a mathematical model of the consequences of lowering the legal drinking age. Method: Using data available from 32 U.S. campuses, the analyses separate underage and legal age drinking groups into an eight-compartment model with different alcohol availability (wetness) for the underage and legal age groups. The model evaluates the likelihood that underage students will incorrectly perceive normative drinking levels to be higher than they actually are (i.e., misperception) and adjust their drinking accordingly by varying the interaction between underage students in …