213 research outputs found
A Blessed Event: How Intended Parents Conceptualize Transnational Surrogacy
This study analyzes the language intended parents (IP) use when they disclose their plans to have a child through surrogacy to their friends and family. Through narrative interviews and content analysis of Facebook posts, blog, and chat forum posts, I found that many of the IP narratives, both online and in-person, utilized animal metaphors in explaining surrogacy to family members and young children. Two other elements also emerged: first, that it was important not only what the IPs said when they shared their decision to have a child through surrogacy but also when. Most IPs sought advice as to when they should tell people rather than what they should say. Second, the question of who controls the narrative—whose story it is to tell—given that the agentive role is now shared between two “mothers.” An intended mother seems to find herself compelled to try to maintain control over her (displaced) pregnancy, while a surrogate mother has a different discursive task: to reconcile the tension between the commodity relationship and the maternal relationship, knowing that the baby is not, in the end, hers
Effects of Celiac Disease on Religion and Language
Celiac disease is an autoimmune disease that prevents people from digesting gluten. The diagnosis of Celiac impacts more than physical health, it irrevocably alters a person’s conception of self. Ordinary activities like airport travel, staying in hotels, and worship become complicated. For example, receiving Communion in the Roman Catholic faith is one of the ways people maintain their close relationship to God. Because the wafers used are made of gluten, those with Celiac are prevented from partaking in this sacred ritual. This leads to increased feelings of isolation and alienation from both the religious community and God. Another way it alters a person’s self-conception is by changing the very language they use. For instance, they might use new lingo such as the word “glutard.” A contraction of the words “gluten” and “retarded,” many use the term to inject humor into an often grim situation. It is an ironic term of self-reference used on social media when one has been exposed or is pointing out the dark humor that is often a part of life with Celiac disease. Those with Celiac disease often find these kinds of everyday experiences more problematic than those without, who often take these things for granted
Retarded coordinates based at a world line, and the motion of a small black hole in an external universe
In the first part of this article I present a system of retarded coordinates
based at an arbitrary world line of an arbitrary curved spacetime. The
retarded-time coordinate labels forward light cones that are centered on the
world line, the radial coordinate is an affine parameter on the null generators
of these light cones, and the angular coordinates are constant on each of these
generators. The spacetime metric in the retarded coordinates is displayed as an
expansion in powers of the radial coordinate and expressed in terms of the
world line's acceleration vector and the spacetime's Riemann tensor evaluated
at the world line. The formalism is illustrated in two examples, the first
involving a comoving world line of a spatially-flat cosmology, the other
featuring an observer in circular motion in the Schwarzschild spacetime. The
main application of the formalism is presented in the second part of the
article, in which I consider the motion of a small black hole in an empty
external universe. I use the retarded coordinates to construct the metric of
the small black hole perturbed by the tidal field of the external universe, and
the metric of the external universe perturbed by the presence of the black
hole. Matching these metrics produces the MiSaTaQuWa equations of motion for
the small black hole.Comment: 20 pages, revtex4, 2 figure
Restaurants and Relationships: Varied Experiences with Celiac Disease
During the summer, we conducted interviews for Professor Hillary Crane with people who had either celiac disease or gluten intolerance. It quickly became apparent that people experience celiac disease in vastly different ways. We cover these varying experiences in terms of symptoms, eating at restaurants, and personal relationships. There are common symptoms associated with celiac disease and gluten intolerance, but most people have just one or a set few of these symptoms. Due to varying symptoms and severity of them, there is no definitive celiac symptom or experience. This is true for social events involving food and for personal relationships. As seen in our interviews, most people with celiac do not approach things in the same way, and often the way they do go about it is dependent on their symptoms. Most diseases have set symptoms, and a shared experience, but with these varying experiences, it is difficult to define celiac. This research shows how celiac is an indefinable disease in terms of its shared experience and social impact
Finding a Spherically Symmetric Cosmology from Observations in Observational Coordinates -- Advantages and Challenges
One of the continuing challenges in cosmology has been to determine the
large-scale space-time metric from observations with a minimum of assumptions
-- without, for instance, assuming that the universe is almost
Friedmann-Lema\^{i}tre-Robertson-Walker (FLRW). If we are lucky enough this
would be a way of demonstrating that our universe is FLRW, instead of
presupposing it or simply showing that the observations are consistent with
FLRW. Showing how to do this within the more general spherically symmetric,
inhomogeneous space-time framework takes us a long way towards fulfilling this
goal. In recent work researchers have shown how this can be done both in the
traditional Lema\^{i}tre-Tolman-Bondi (LTB) 3 + 1 coordinate framework, and in
the observational coordinate (OC) framework. In this paper we investigate the
stability of solutions, and the use of data in the OC field equations including
their time evolution and compare both approaches with respect to the
singularity problem at the maximum of the angular-diameter distance, the
stability of solutions, and the use of data in the field equations. This allows
a more detailed account and assessment of the OC integration procedure, and
enables a comparison of the relative advantages of the two equivalent solution
frameworks. Both formulations and integration procedures should, in principle,
lead to the same results. However, as we show in this paper, the OC procedure
manifests certain advantages, particularly in the avoidance of coordinate
singularities at the maximum of the angular-diameter distance, and in the
stability of the solutions obtained. This particular feature is what allows us
to do the best fitting of the data to smooth data functions and the possibility
of constructing analytic solutions to the field equations.Comment: 31 page
The Limits on Cosmological Anisotropies and Inhomogeneities from COBE Data
Assuming that the cosmological principle holds, Maartens, Ellis and Stoeger
(MES) recently constructed a detailed scheme linking anisotropies in the cosmic
background radiation (CMB) with anisotropies and inhomogeneities in the large
scale structure of the universe and showed how to place limits on those
anisotropies and inhomogeneities simply by using CMB quadrupole and octupole
limits. First we indicate and discuss the connection between the covariant
multipole moments of the temperature anisotropy used in the MES scheme and the
quadrupole and octupole results from COBE. Then we introduce those results into
the MES limit equations to obtain definite quantitative limits on the complete
set of cosmological measures of anisotropy and inhomogeneity.
We find that all the anisotropy measures are less than 10^{-4} in the case of
those not affected by the expansion rate H, and less than 10^{-6} Mpc^{-1} in
the case of those which are. These results quantitatively demonstrate that the
observable universe is indeed close to Friedmann-Lemaitre-Robertson-Walker
(FLRW) on the largest scales, and can be adequately modelled by an almost-FLRW
model -- that is, the anisotropies and inhomogeneities characterizing the
observable universe on the largest scales are not too large to be considered
perturbations to FLRW.Comment: Original paper with corrections. ApJ 476 435 (1997) erratum to appear
ApJ Sept 199
The effect of fine motor skills, handwriting, and typing on reading development
Discussions on the contribution of motor skills and processes to learning to read has a long history. Previous work is essentially divided into two separate strands, namely the contributions of fine motor skills (FMS) to reading and the influence of writing versus typing. In the current 2 2 3 mixed, single-blind, and randomly assigned experiment, we tested both strands together. A total of 87 children learned to decode pseudowords in either typing or writing conditions in which their FMS were either impaired or not. Decoding gains were measured at pretest, posttest, and followup, with FMS and working memory included as participant variable predictors. Findings indicated that FMS and working memory predicted decoding gains. Importantly, children performed best when typing if in the impaired FMS condition. Results have implications for motor representation theories of writing and for instruction of children with FMS impairments
Differential Density Statistics of Galaxy Distribution and the Luminosity Function
This paper uses data obtained from the galaxy luminosity function (LF) to
calculate two types of radial number densities statistics of the galaxy
distribution as discussed in Ribeiro (2005), namely the differential density
and the integral differential density . By applying the
theory advanced by Ribeiro and Stoeger (2003), which connects the relativistic
cosmology number counts with the astronomically derived LF, the differential
number counts are extracted from the LF and used to calculate both
and with various cosmological distance definitions,
namely the area distance, luminosity distance, galaxy area distance and
redshift distance. LF data are taken from the CNOC2 galaxy redshift survey and
and are calculated for two cosmological models:
Einstein-de Sitter and an , standard
cosmology. The results confirm the strong dependency of both statistics on the
distance definition, as predicted in Ribeiro (2005), as well as showing that
plots of and against the luminosity and redshift
distances indicate that the CNOC2 galaxy distribution follows a power law
pattern for redshifts higher than 0.1. These findings bring support to
Ribeiro's (2005) theoretical proposition that using different cosmological
distance measures in statistical analyses of galaxy surveys can lead to
significant ambiguity in drawing conclusions about the behavior of the observed
large scale distribution of galaxies.Comment: LaTeX, 37 pages, 6 tables, 10 figures. Accepted for publication in
"The Astrophysical Journal
A fully covariant description of CMB anisotropies
Starting from the exact non-linear description of matter and radiation, a
fully covariant and gauge-invariant formula for the observed temperature
anisotropy of the cosmic microwave background (CBR) radiation, expressed in
terms of the electric () and magnetic () parts of the Weyl
tensor, is obtained by integrating photon geodesics from last scattering to the
point of observation today. This improves and extends earlier work by Russ et
al where a similar formula was obtained by taking first order variations of the
redshift. In the case of scalar (density) perturbations, is related to
the harmonic components of the gravitational potential and the usual
dominant Sachs-Wolfe contribution to the
temperature anisotropy is recovered, together with contributions due to the
time variation of the potential (Rees-Sciama effect), entropy and velocity
perturbations at last scattering and a pressure suppression term important in
low density universes. We also explicitly demonstrate the validity of assuming
that the perturbations are adiabatic at decoupling and show that if the surface
of last scattering is correctly placed and the background universe model is
taken to be a flat dust dominated Friedmann-Robertson-Walker model (FRW), then
the large scale temperature anisotropy can be interpreted as being due to the
motion of the matter relative to the surface of constant temperature which
defines the surface of last scattering on those scales.Comment: 18 pages LaTeX, 1 figure. Submitted to Classical and Quantum Gravity.
Also available at http://shiva.mth.uct.ac.za/preprints/9705.htm
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