12,624 research outputs found
WHAT IS A HERPETOLOGIST AND HOW CAN I BECOME ONE?
The following is the first in the JNAH series in which we address a variety of topics on herpetology based on essays from our upcoming book âHow to Be a Herpetologist,â. We will also answer frequently asked questions we and other professional herpetologists receive from students, colleagues, and the general public about herpetology as a career or an avocation
Childrenâs Futures: Lessons From a Second-Generation Community Change Initiative
· This article describes Childrenâs Futures, a 10-year initiative in Trenton, N.J., that seeks to improve the health and well-being of children from 0 to 3 years old and ensure that they are ready for school.
· During the first five years, the initiative was successful in implementing a number of evidence-based practices to improve childrenâs health, such as providing home visits to pregnant women, measuring and improving the quality of day care centers, and improving the use of information systems to track childhood immunizations.
· Efforts to provide services for fathers and improve home-based child care were not successful; these are areas in which there are not any evidence-based practices.
· Leveraging public and private money beyond the Robert Wood Johnson Foundationâs substantial $20 million commitment proved challenging because the foundationâs commitment was so large. The authors recommend obtaining agreements for matching funds prior to finalizing commitments.
· A lack of attention to initiative-wide communications hindered integration across programs.
· A need for a citywide data system was identified; this is being implemented in the second five-year funding cycle
2D Dilaton-Maxwell Gravity as a Fixed Point of the Renormalization Group
A general model of dialton-Maxwell gravity in two dimensions is investigated.
The corresponding one-loop effective action and the generalized
-functions are obtained. A set of models that are fixed points of the
renormalization group equations are presented.Comment: 7 pages, LaTeX file, UB-ECM-PF 92/Mar1
Black Hole Solutions of Kaluza-Klein Supergravity Theories and String Theory
We find U(1)_{E} \times U(1)_{M} non-extremal black hole solutions of
6-dimensional Kaluza-Klein supergravity theories. Extremal solutions were found
by Cveti\v{c} and Youm\cite{C-Y}. Multi black hole solutions are also
presented. After electro-magnetic duality transformation is performed, these
multi black hole solutions are mapped into the the exact solutions found by
Horowitz and Tseytlin\cite{H-T} in 5-dimensional string theory compactified
into 4-dimensions. The massless fields of this theory can be embedded into the
heterotic string theory compactified on a 6-torus. Rotating black hole
solutions can be read off those of the heterotic string theory found by
Sen\cite{Sen3}.Comment: 23 pages text(latex), a figure upon reques
Branes as BIons
A BIon may be defined as a finite energy solution of a non-linear field
theory with distributional sources. By contrast a soliton is usually defined to
have no sources. I show how harmonic coordinates map the exteriors of the
topologically and causally non-trivial spacetimes of extreme p-branes to BIonic
solutions of the Einstein equations in a topologically trivial spacetime in
which the combined gravitational and matter energy momentum is located on
distributional sources. As a consequence the tension of BPS p-branes is
classically unrenormalized. The result holds equally for spacetimes with
singularities and for those, like the M-5-brane, which are everywhere
singularity free.Comment: Latex, 9 pages, no figure
Moduli, Scalar Charges, and the First Law of Black Hole Thermodynamics
We show that under variation of moduli fields the first law of black
hole thermodynamics becomes , where are the scalar charges. We also show
that the ADM mass is extremized at fixed , , when the moduli
fields take the fixed value which depend only on electric
and magnetic charges. It follows that the least mass of any black hole with
fixed conserved electric and magnetic charges is given by the mass of the
double-extreme black hole with these charges. Our work allows us to interpret
the previously established result that for all extreme black holes the moduli
fields at the horizon take a value depending only
on the electric and magnetic conserved charges: is such
that the scalar charges .Comment: 3 pages, no figures, more detailed versio
Self-Duality in Nonlinear Electromagnetism
We discuss duality invariant interactions between electromagnetic fields and
matter. The case of scalar fields is treated in some detail.Comment: 10 pages, full postscript also available from
http://theor1.lbl.gov/www/theorygroup/papers/40770.p
Sato-Crutchfield formulation for some Evolutionary Games
The Sato-Crutchfield equations are studied analytically and numerically. The
Sato-Crutchfield formulation is corresponding to losing memory. Then
Sato-Crutchfield formulation is applied for some different types of games
including hawk-dove, prisoner's dilemma and the battle of the sexes games. The
Sato-Crutchfield formulation is found not to affect the evolutionarily stable
strategy of the ordinary games. But choosing a strategy becomes purely random
independent on the previous experiences, initial conditions, and the rules of
the game itself. Sato-Crutchfield formulation for the prisoner's dilemma game
can be considered as a theoretical explanation for the existence of cooperation
in a population of defectors.Comment: 9 pages, 3 figures, accepted for Int. J. Mod. Phys.
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