22,818 research outputs found
Ethical approaches to family planning in Africa
Africa has historically provided the geographical flashpoint of ethical issues relating to family planning programs. Until recently in Sub-Saharan Africa, advocacy of family planning by non-Africans was unacceptable and by Africans politically inadvisable. This has changed in the 1980s. The health rationale for family planning is backed by strong evidence, especially in Africa, where infant and maternal mortality and morbidity rates are high. Population growth in many African countries impedes development, which cannot keep up with needs. Earlier attempts to offer family planning aid were often politically inept and endangered the needed partnership between donor and developing countries. Theoretical arguments and abstract demographic projections are less persuasive than carefully designed programs geared to the health and well-being of communitities that help plan them. Increased cooperation between donor and developing countries has helped resolve some of the ethical difficulties that beset family planning programs. This report summarizes many of the practical, ethical and cultural considerations in making family planning aid acceptable.Health Monitoring&Evaluation,Adolescent Health,Agricultural Knowledge&Information Systems,Gender and Health,Early Child and Children's Health
Graph-based Features for Automatic Online Abuse Detection
While online communities have become increasingly important over the years,
the moderation of user-generated content is still performed mostly manually.
Automating this task is an important step in reducing the financial cost
associated with moderation, but the majority of automated approaches strictly
based on message content are highly vulnerable to intentional obfuscation. In
this paper, we discuss methods for extracting conversational networks based on
raw multi-participant chat logs, and we study the contribution of graph
features to a classification system that aims to determine if a given message
is abusive. The conversational graph-based system yields unexpectedly high
performance , with results comparable to those previously obtained with a
content-based approach
Matching Kasteleyn Cities for Spin Glass Ground States
As spin glass materials have extremely slow dynamics, devious numerical
methods are needed to study low-temperature states. A simple and fast
optimization version of the classical Kasteleyn treatment of the Ising model is
described and applied to two-dimensional Ising spin glasses. The algorithm
combines the Pfaffian and matching approaches to directly strip droplet
excitations from an excited state. Extended ground states in Ising spin glasses
on a torus, which are optimized over all boundary conditions, are used to
compute precise values for ground state energy densities.Comment: 4 pages, 2 figures; minor clarification
Strong-coupling behaviour in discrete Kardar-Parisi-Zhang equations
We present a systematic discretization scheme for the Kardar-Parisi-Zhang
(KPZ) equation, which correctly captures the strong-coupling properties of the
continuum model. In particular we show that the scheme contains no finite-time
singularities in contrast to conventional schemes. The implications of these
results to i) previous numerical integration of the KPZ equation, and ii) the
non-trivial diversity of universality classes for discrete models of `KPZ-type'
are examined. The new scheme makes the strong-coupling physics of the KPZ
equation more transparent than the original continuum version and allows the
possibility of building new continuum models which may be easier to analyse in
the strong-coupling regime.Comment: 21 pages, revtex, 2 figures, submitted to J. Phys.
Determination of surface resistance and magnetic penetration depth of superconducting YBa2Cu3O(7-delta) thin films by microwave power transmission measurements
A novel waveguide power transmission measurement technique was developed to extract the complex conductivity of superconducting thin films at microwave frequencies. The microwave conductivity was taken of two laser ablated YBa2Cu3O(7-delta) thin films on LaAlO3 with transition temperatures of approx. 86.3 and 82 K, respectively, in the temperature range 25 to 300 K. From the conductivity values, the penetration depth was found to be approx. 0.54 and 0.43 micron, and the surface resistance (R sub s) to be approx. 24 and 36 micro-Ohms at 36 GHz and 76 K for the two films under consideration. The R sub s values were compared with those obtained from the change in the Q-factor of a 36 GHz Te sub 011-mode (OFHC) copper cavity by replacing one of its end walls with the superconducting sample. This technique allows noninvasive characterization of high transition temperature superconducting thin films at microwave frequencies
THE ACCUSED IS ENTERING THE COURTROOM: THE LIVE-TWEETING OF A MURDER TRIAL.
© 2017 Informa UK Limited, trading as Taylor & Francis GroupThe use of social media is now widely accepted within journalism as an outlet for news information. Live tweeting of unfolding events is standard practice. In March 2014, Oscar Pistorius went on trial in the Gauteng High Court for murder. Hundreds of journalists present began live-tweeting coverage, an unprecedented combination of international interest, permission to use technology and access which resulted in massive streams of consciousness reports of events as they unfolded. Based on a corpus of Twitter feeds of twenty-four journalists covering the trial, this study analyses the content and strategies of these feeds in order to present an understanding of how microblogging is used as a live reporting tool. This study shows the development of standardised language and strategies in reporting on Twitter, concluding that journalists adopt a narrow range of approaches, with no significant variation in terms of gender, location, or medium. This is in contrast to earlier studies in the field (Awad, 2006, Hedman, 2015; Kothari, 2010; Lariscy, Avery, Sweetser, & Howes, 2009 Lasorsa, 2012; Lasorsa, Lewis, & Holton, 2011; Sigal, 1999, Vis, 2013).Peer reviewe
Failure properties of loaded fiber bundles having a lower cutoff in fiber threshold distribution
Presence of lower cutoff in fiber threshold distribution may affect the
failure properties of a bundle of fibers subjected to external load. We
investigate this possibility both in a equal load sharing (ELS) fiber bundle
model and in local load sharing (LLS) one. We show analytically that in ELS
model, the critical strength gets modified due to the presence of lower cutoff
and it becomes bounded by an upper limit. Although the dynamic exponents for
the susceptibility and relaxation time remain unchanged, the avalanche size
distribution shows a permanent deviation from the mean-fiels power law. In the
LLS model, we analytically estimate the upper limit of the lower cutoff above
which the bundle fails at one instant. Also the system size variation of
bundle's strength and the avalanche statistics show strong dependence on the
lower cutoff level.Comment: 7 pages and 7 figure
The Effect of Pure State Structure on Nonequilibrium Dynamics
Motivated by short-range Ising spin glasses, we review some rigorous results
and their consequences for the relation between the number/nature of
equilibrium pure states and nonequilibrium dynamics. Two of the consequences
for spin glass dynamics following a deep quench to a temperature with broken
spin flip symmetry are: (1) Almost all initial configurations lie on the
boundary between the basins of attraction of multiple pure states. (2) Unless
there are uncountably many pure states with almost all pairs having zero
overlap, there can be no equilibration to a pure state as time goes to
infinity. We discuss the relevance of these results to the difficulty of
equilibration of spin glasses. We also review some results concerning the
``nature vs. nurture'' problem of whether the large-time behavior of both
ferromagnets and spin glasses following a deep quench is determined more by the
initial configuration or by the dynamics realization.Comment: 20 page
Nature of the Spin Glass State
The nature of the spin glass state is investigated by studying changes to the
ground state when a weak perturbation is applied to the bulk of the system. We
consider short range models in three and four dimensions and the infinite range
Sherrington-Kirkpatrick (SK) and Viana-Bray models. Our results for the SK and
Viana-Bray models agree with the replica symmetry breaking picture. The data
for the short range models fit naturally a picture in which there are large
scale excitations which cost a finite energy but whose surface has a fractal
dimension, , less than the space dimension . We also discuss a possible
crossover to other behavior at larger length scales than the sizes studied.Comment: 4 pages, 4 postscript figures included. Final version, only minor
changes mad
Low Energy Excitations in Spin Glasses from Exact Ground States
We investigate the nature of the low-energy, large-scale excitations in the
three-dimensional Edwards-Anderson Ising spin glass with Gaussian couplings and
free boundary conditions, by studying the response of the ground state to a
coupling-dependent perturbation introduced previously. The ground states are
determined exactly for system sizes up to 12^3 spins using a branch and cut
algorithm. The data are consistent with a picture where the surface of the
excitations is not space-filling, such as the droplet or the ``TNT'' picture,
with only minimal corrections to scaling. When allowing for very large
corrections to scaling, the data are also consistent with a picture with
space-filling surfaces, such as replica symmetry breaking. The energy of the
excitations scales with their size with a small exponent \theta', which is
compatible with zero if we allow moderate corrections to scaling. We compare
the results with data for periodic boundary conditions obtained with a genetic
algorithm, and discuss the effects of different boundary conditions on
corrections to scaling. Finally, we analyze the performance of our branch and
cut algorithm, finding that it is correlated with the existence of
large-scale,low-energy excitations.Comment: 18 Revtex pages, 16 eps figures. Text significantly expanded with
more discussion of the numerical data. Fig.11 adde
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