80 research outputs found
Enhancing Accountability: ServSafe™ Impact Template Delivers
Generating statewide impact data from Extension programs can be challenging. To streamline reporting, Extension specialists, with the help of county agents and administrators, generated a statewide impact statement for the ServSafe™ program in Virginia. This template includes knowledge gain, behavior change, and economic impact from participants generated from current standardized evaluation methods used by all Extension educators across the state. Providing this template for agents resulted in easier, more consistent yearly reporting for those agents administering the program
Comment on: "The Casimir force on a piston in the spacetime with extra compactified dimensions" [Phys. Lett. B 668 (2008) 72]
We offer a clarification of the significance of the indicated paper of H.
Cheng. Cheng's conclusions about the attractive nature of Casimir forces
between parallel plates are valid beyond the particular model in which he
derived them; they are likely to be relevant to other recent literature on the
effects of hidden dimensions on Casimir forces.Comment: 6 pages, 1 figur
Species-Specific Responses of Juvenile Rockfish to Elevated pCO2: From Behavior to Genomics
In the California Current ecosystem, global climate change is predicted to trigger large-scale changes in ocean chemistry within this century. Ocean acidification—which occurs when increased levels of atmospheric CO2 dissolve into the ocean—is one of the biggest potential threats to marine life. In a coastal upwelling system, we compared the effects of chronic exposure to low pH (elevated pCO2) at four treatment levels (i.e., pCO2 = ambient [500], moderate [750], high [1900], and extreme [2800 μatm]) on behavior, physiology, and patterns of gene expression in white muscle tissue of juvenile rockfish (genus Sebastes), integrating responses from the transcriptome to the whole organism level. Experiments were conducted simultaneously on two closely related species that both inhabit kelp forests, yet differ in early life history traits, to compare high-CO2 tolerance among species. Our findings indicate that these congeners express different sensitivities to elevated CO2 levels. Copper rockfish (S. caurinus) exhibited changes in behavioral lateralization, reduced critical swimming speed, depressed aerobic scope, changes in metabolic enzyme activity, and increases in the expression of transcription factors and regulatory genes at high pCO2 exposure. Blue rockfish (S. mystinus), in contrast, showed no significant changes in behavior, swimming physiology, or aerobic capacity, but did exhibit significant changes in the expression of muscle structural genes as a function of pCO2, indicating acclimatization potential. The capacity of long-lived, late to mature, commercially important fish to acclimatize and adapt to changing ocean chemistry over the next 50–100 years is likely dependent on species-specific physiological tolerances
Casimir Effect: The Classical Limit
We analyze the high temperature (or classical) limit of the Casimir effect. A
useful quantity which arises naturally in our discussion is the ``relative
Casimir energy", which we define for a configuration of disjoint conducting
boundaries of arbitrary shapes, as the difference of Casimir energies between
the given configuration and a configuration with the same boundaries infinitely
far apart. Using path integration techniques, we show that the relative Casimir
energy vanishes exponentially fast in temperature. This is consistent with a
simple physical argument based on Kirchhoff's law. As a result the ``relative
Casimir entropy", which we define in an obviously analogous manner, tends, in
the classical limit, to a finite asymptotic value which depends only on the
geometry of the boundaries. Thus the Casimir force between disjoint pieces of
the boundary, in the classical limit, is entropy driven and is governed by a
dimensionless number characterizing the geometry of the cavity. Contributions
to the Casimir thermodynamical quantities due to each individual connected
component of the boundary exhibit logarithmic deviations in temperature from
the behavior just described. These logarithmic deviations seem to arise due to
our difficulty to separate the Casimir energy (and the other thermodynamical
quantities) from the ``electromagnetic'' self-energy of each of the connected
components of the boundary in a well defined manner. Our approach to the
Casimir effect is not to impose sharp boundary conditions on the fluctuating
field, but rather take into consideration its interaction with the plasma of
``charge carriers'' in the boundary, with the plasma frequency playing the role
of a physical UV cutoff. This also allows us to analyze deviations from a
perfect conductor behavior.Comment: latex, 56 pages, one eps figure. Major improvements of presentation
(especially in Section 2). No change in the conclusions. Connection with the
works of Balian et al. on the Casimir effect is clarified. Abstract changed,
typos correcte
Zeta function method and repulsive Casimir forces for an unusual pair of plates at finite temperature
We apply the generalized zeta function method to compute the Casimir energy
and pressure between an unusual pair of parallel plates at finite temperature,
namely: a perfectly conducting plate and an infinitely permeable one. The high
and low temperature limits of these quantities are discussed; relationships
between high and low temperature limits are estabkished by means of a modified
version of the temperature inversion symmetry.Comment: latex file 9 pages, 3 figure
Automated Analysis of Cryptococcal Macrophage Parasitism Using GFP-Tagged Cryptococci
The human fungal pathogens Cryptococcus neoformans and C. gattii cause life-threatening infections of the central nervous system. One of the major characteristics of cryptococcal disease is the ability of the pathogen to parasitise upon phagocytic immune effector cells, a phenomenon that correlates strongly with virulence in rodent models of infection. Despite the importance of phagocyte/Cryptococcus interactions to disease progression, current methods for assaying virulence in the acrophage system are both time consuming and low throughput. Here, we introduce the first stable and fully characterised GFP–expressing derivatives of two widely used cryptococcal strains: C. neoformans serotype A type strain H99 and C. gattii serotype B type strain R265. Both strains show unaltered responses to environmental and host stress conditions and no deficiency in virulence in the macrophage model system. In addition, we report the development of a method to effectively and rapidly investigate macrophage parasitism by flow cytometry, a technique that preserves the accuracy of current approaches but offers a four-fold improvement in speed
Quantum Fields and Extended Objects in Space-Times with Constant Curvature Spatial Section
The heat-kernel expansion and -regularization techniques for quantum
field theory and extended objects on curved space-times are reviewed. In
particular, ultrastatic space-times with spatial section consisting in manifold
with constant curvature are discussed in detail. Several mathematical results,
relevant to physical applications are presented, including exact solutions of
the heat-kernel equation, a simple exposition of hyperbolic geometry and an
elementary derivation of the Selberg trace formula. With regards to the
physical applications, the vacuum energy for scalar fields, the one-loop
renormalization of a self-interacting scalar field theory on a hyperbolic
space-time, with a discussion on the topological symmetry breaking, the finite
temperature effects and the Bose-Einstein condensation, are considered. Some
attempts to generalize the results to extended objects are also presented,
including some remarks on path integral quantization, asymptotic properties of
extended objects and a novel representation for the one-loop (super)string free
energy.Comment: Latex file, 122 page
Turning I into me: Imagining your future self.
A widely endorsed belief is that perceivers imagine their present selves using a different representational format than imagining their future selves (i.e., near future=first-person; distant future=third-person). But is this really the case? Responding to the paucity of work on this topic, here we considered how temporal distance influences the extent to which individuals direct their attention outward or inward during a brief imaginary episode. Using a non-verbal measure of visual perspective taking (i.e., letter-drawing task) our results confirmed the hypothesized relation between temporal distance and conceptions of the self. Whereas simulations of an event in the near future were dominated by a first-person representation of the self, this switched to a third-person depiction when the event was located in the distant future. Critically, this switch in vantage point was restricted to self-related simulations. The theoretical and practical implications of these findings are considered
New Developments in the Casimir Effect
We provide a review of both new experimental and theoretical developments in
the Casimir effect. The Casimir effect results from the alteration by the
boundaries of the zero-point electromagnetic energy. Unique to the Casimir
force is its strong dependence on shape, switching from attractive to repulsive
as function of the size, geometry and topology of the boundary. Thus the
Casimir force is a direct manifestation of the boundary dependence of quantum
vacuum.
We discuss in depth the general structure of the infinities in the field
theory which are removed by a combination of zeta-functional regularization and
heat kernel expansion. Different representations for the regularized vacuum
energy are given. The Casimir energies and forces in a number of configurations
of interest to applications are calculated. We stress the development of the
Casimir force for real media including effects of nonzero temperature, finite
conductivity of the boundary metal and surface roughness. Also the combined
effect of these important factors is investigated in detail on the basis of
condensed matter physics and quantum field theory at nonzero temperature.
The experiments on measuring the Casimir force are also reviewed, starting
first with the older measurements and finishing with a detailed presentation of
modern precision experiments. The latter are accurately compared with the
theoretical results for real media.
At the end of the review we provide the most recent constraints on the
corrections to Newtonian gravitational law and other hypothetical long-range
interactions at submillimeter range obtained from the Casimir force
measurements.Comment: 275 pages,29 figures, to appear in Physics Report
Gene Expression Profiling of Bis(tri-n-butyltin)oxide (TBTO)-Induced Immunotoxicity in Mice and Rats
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