937 research outputs found
Improving the prospects for sustainable ICT projects in the developing world
Projects that bring information and communications technology (ICT) to the developing world -and especially to rural areas -have the potential to empower the disenfranchised, foster economic opportunity, and narrow the digital divide that threatens to widen global disparity between the haves and the have-nots. However, given the remarkable growth of such undertakings around the world, there has been little corresponding effort made to address the vital issues of long term project sustainability and the diverse motivations and incentives facing the actors involved. As a result, these projects continue to be implemented sporadically and in a piecemeal fashion, which in turn hinders our ability to define success and recommend best practices for implementing and/or scaling them. Through an analysis of public-private partnerships (PPPs), the prevailing vehicle for project implementation today, the article addresses the issue of sustainability through partnerships, and also asserts that developing world technology recipients must be considered as stakeholders, as they hold the key to project sustainability. Following an overview of both theory and the current state of ICT-related development projects, the article provides a case study of a Sri Lankan-based pilot project involving multiple stakeholders. This case reveals important success factors that can be applied to future developing world ICT projects
Effective Field Theory Approach to High-Temperature Thermodynamics
An effective field theory approach is developed for calculating the
thermodynamic properties of a field theory at high temperature and weak
coupling . The effective theory is the 3-dimensional field theory obtained
by dimensional reduction to the bosonic zero-frequency modes. The parameters of
the effective theory can be calculated as perturbation series in the running
coupling constant . The free energy is separated into the contributions
from the momentum scales and , respectively. The first term can be
written as a perturbation series in . If all forces are screened at the
scale , the second term can be calculated as a perturbation series in
beginning at order . The parameters of the effective theory satisfy
renormalization group equations that can be used to sum up leading logarithms
of . We apply this method to a massless scalar field with a
interaction, calculating the free energy to order and the
screening mass to order .Comment: 40 pages, LaTeX, 5 uuecoded figure
Covariant derivative expansion of fermionic effective action at high temperatures
We derive the fermionic contribution to the 1-loop effective action for A_4
and A_i fields at high temperatures, assuming that gluon fields are slowly
varying but allowing for an arbitrary amplitude of A_4.Comment: RevTex 4, 11 pages, 3 figures. Version 2: Typos corrected; magnetic
fields restricted to parallel sector. Version accepted for publication in PR
Covariant derivative expansion of Yang-Mills effective action at high temperatures
Integrating out fast varying quantum fluctuations about Yang--Mills fields
A_i and A_4, we arrive at the effective action for those fields at high
temperatures. Assuming that the fields A_i and A_4 are slowly varying but that
the amplitude of A_4 is arbitrary, we find a non-trivial effective gauge
invariant action both in the electric and magnetic sectors. Our results can be
used for studying correlation functions at high temperatures beyond the
dimensional reduction approximation, as well as for estimating quantum weights
of classical static configurations such as dyons.Comment: Minor changes. References added. Paper accepted for publication in
Phys.Rev.
Review: The Journal of Dramaturgy, volume 19, issue 2
Contents include: For the Record; An Introduction; Recognition for City of Wine, Brian Quirt, recipient of the 2009 Elliott Hayes Award Introduced by LMDA President Shelley Orr; Brian Quirt\u27s Elliott Hayes Acceptance Speech Washington, D.C. Watergate Restaurant July 18, 2009; Being Dramaturgical, A Conversation about Geoff Proehl\u27s New Book Toward a Dramaturgical Sensibility; Beyond Hamlet: Three Theatre Developments in Denmark; The Alexandrinsky and Renaissancing the Cultural Theatre Medium; The Acting and Dramaturgy of Odin Teatret; A Production Dramaturg and an Installation Dramaturg Discuss Their Approaches to Making Art.
Issue editors: D.J. Hopkins, Lauren Beckhttps://soundideas.pugetsound.edu/lmdareview/1039/thumbnail.jp
Purely perturbative Boltzmann equation for hot non-Abelian gauge theories
In the perturbation theory, trasnport phenomena in hot non-Abelian gauge
theories like QCD are often plagued with infrared singularities or
nonperturbative effects. We show, in the context of the Kadanoff & Baym
formalism, that there are certain nonequilibrium processes which are free from
such difficulties. For these processes, due to an interplay between the
macroscopic and microscopic physics, characteristic time scale (the mesoscale)
naturally enters as an infrared cutoff and purely perturbative description by
the Boltzmann equation is valid.Comment: 4 pages, revtex, to appear in Physical Review
Earthshine observation of vegetation and implication for life detection on other planets - A review of 2001 - 2006 works
The detection of exolife is one of the goals of very ambitious future space
missions that aim to take direct images of Earth-like planets. While
associations of simple molecules present in the planet's atmosphere (,
, etc.) have been identified as possible global biomarkers, we
review here the detectability of a signature of life from the planet's surface,
i.e. the green vegetation. The vegetation reflectance has indeed a specific
spectrum, with a sharp edge around 700 nm, known as the "Vegetation Red Edge"
(VRE). Moreover vegetation covers a large surface of emerged lands, from
tropical evergreen forest to shrub tundra. Thus considering it as a potential
global biomarker is relevant. Earthshine allows to observe the Earth as a
distant planet, i.e. without spatial resolution. Since 2001, Earthshine
observations have been used by several authors to test and quantify the
detectability of the VRE in the Earth spectrum. The egetation spectral
signature is detected as a small 'positive shift' of a few percents above the
continuum, starting at 700 nm. This signature appears in most spectra, and its
strength is correlated with the Earth's phase (visible land versus visible
ocean). The observations show that detecting the VRE on Earth requires a
photometric relative accuracy of 1% or better. Detecting something equivalent
on an Earth-like planet will therefore remain challenging, moreover considering
the possibility of mineral artifacts and the question of 'red edge'
universality in the Universe.Comment: Invited talk in "Strategies for Life Detection" (ISSI Bern, 24-28
April 2006) to appear in a hardcopy volume of the ISSI Space Science Series,
Eds, J. Bada et al., and also in an issue of Space Science Reviews. 13 pages,
8 figures, 1 tabl
Shear Viscosity in the O(N) Model
We compute the shear viscosity in the O(N) model at first nontrivial order in
the large N expansion. The calculation is organized using the 1/N expansion of
the 2PI effective action (2PI-1/N expansion) to next-to-leading order, which
leads to an integral equation summing ladder and bubble diagrams. We also
consider the weakly coupled theory for arbitrary N, using the three-loop
expansion of the 2PI effective action. In the limit of weak coupling and
vanishing mass, we find an approximate analytical solution of the integral
equation. For general coupling and mass, the integral equation is solved
numerically using a variational approach. The shear viscosity turns out to be
close to the result obtained in the weak-coupling analysis.Comment: 37 pages, few typos corrected; to appear in JHE
Washington Park Main Street Plan
There is an immense variety of privately owned businesses. They will be stakeholders because their businesses are located there, but they will also be assets in themselves in drawing people to the area. There is basically everything anyone could possible want or need in this area. There are two gas stations, a Family Dollar, a liquor store, a few sit down restaurants, numerous places where one can get a quick bite to eat, a frame shop, a clothing store, a pawn shop, a store with fresh produce (which is hard to find in urban areas), a store that sells sports uniforms, a frame shop, a lawyerʼs office, an animal hospital, two Laundromats, a record shop, a health food store, two cell phone stores, an automotive shop, and a karate school with an afterschool program. With such variety, it will draw people to the area and then give them other reasons to keep coming back
A non-perturbative contribution to jet quenching
It has been argued by Caron-Huot that infrared contributions to the jet
quenching parameter in hot QCD, denoted by qhat, can be extracted from an
analysis of a certain static-potential related observable within the
dimensionally reduced effective field theory. Following this philosophy, the
order of magnitude of a non-perturbative contribution to qhat from the
colour-magnetic scale, g^2T/pi, is estimated. The result is small; it is
probably below the parametrically perturbative but in practice slowly
convergent contributions from the colour-electric scale, whose all-orders
resummation therefore remains an important challenge.Comment: 4 pages. v2: clarifications, published versio
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