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Stressful and positive experiences of women who served in Vietnam
Experiences of women who served during the Vietnam War have been described in interviews/anecdotal reports but rarely in empirical literature. Potential positive (versus negative) aspects of service or its impact on well-being are seldom considered. We describe stressful and positive experiences reported by approximately 1,300 female military personnel, Red Cross workers, and others deployed to Vietnam. Prominent stressful (e.g., negative living/working conditions) and positive (e.g., interpersonal relationships) themes and differences based on trauma history, Vietnam experiences, and group membership are explored. We evaluate associations between themes and psychological well-being. Findings provide insight into experiences of this understudied group of women
Breaking the self-averaging properties of spatial galaxy fluctuations in the Sloan Digital Sky Survey - Data Release Six
Statistical analyses of finite sample distributions usually assume that
fluctuations are self-averaging, i.e. that they are statistically similar in
different regions of the given sample volume. By using the scale-length method,
we test whether this assumption is satisfied in several samples of the Sloan
Digital Sky Survey Data Release Six. We find that the probability density
function (PDF) of conditional fluctuations, filtered on large enough spatial
scales (i.e., r>30 Mpc/h), shows relevant systematic variations in different
sub-volumes of the survey. Instead for scales r<30 Mpc/h the PDF is
statistically stable, and its first moment presents scaling behavior with a
negative exponent around one. Thus while up to 30 Mpc/h galaxy structures have
well-defined power-law correlations, on larger scales it is not possible to
consider whole sample average quantities as meaningful and useful statistical
descriptors. This situation is due to the fact that galaxy structures
correspond to density fluctuations which are too large in amplitude and too
extended in space to be self-averaging on such large scales inside the sample
volumes: galaxy distribution is inhomogeneous up to the largest scales, i.e. r
~ 100 Mpc/h, probed by the SDSS samples. We show that cosmological corrections,
as K-corrections and standard evolutionary corrections, do not qualitatively
change the relevant behaviors. Finally we show that the large amplitude galaxy
fluctuations observed in the SDSS samples are at odds with the predictions of
the standard LCDM model of structure formation.(Abridged version).Comment: 32 pages, 28 figures, accepted for publication in Astronomy and
Astrophysics. A higher resolution version is available at
http://pil.phys.uniroma1.it/~sylos/fsl_highlights.html . Version v2 has been
corrected to match the published on
Implementation of the American Recovery and Reinvestment Act: Workforce Development and Unemployment Insurance Provisions
Universal fractal scaling of self-organized networks
There is an abundance of literature on complex networks describing a variety of relationships among units in social, biological, and technological systems. Such networks, consisting of interconnected nodes, are often self-organized, naturally emerging without any overarching designs on topological structure yet enabling efficient interactions among nodes. Here we show that the number of nodes and the density of connections in such self-organized networks exhibit a power law relationship. We examined the size and connection density of 46 self-organizing networks of various biological, social, and technological origins, and found that the size-density relationship follows a fractal relationship spanning over 6 orders of magnitude. This finding indicates that there is an optimal connection density in self-organized networks following fractal scaling regardless of their sizes
Basic properties of galaxy clustering in the light of recent results from the Sloan Digital Sky Survey
We discuss some of the basic implications of recent results on galaxy
correlations published by the SDSS collaboration. In particular we focus on the
evidence which has been recently presented for the scale and nature of the
transition to homogeneity in the galaxy distribution, and results which
describe the dependence of clustering on luminosity. The two questions are in
fact strictly entangled, as the stability of the measure of the amplitude of
the correlation function depends on the scale at which the mean density becomes
well defined. We note that the recent results which indicate the convergence to
well defined homogeneity in a volume equivalent to that of a sphere of radius
70 Mpc/h, place in doubt previous detections of ``luminosity bias'' from
measures of the amplitude of the correlation function. We emphasize that the
way to resolve these issues is to first use, in volume limited samples
corresponding to different ranges of luminosity, the unnormalized two point
statistics to establish the scale (and value) at which the mean density becomes
well defined. We note also that the recent SDSS results for these statistics
are in good agreement with those obtained by us through analyses of many
previous samples, confirming in particular that the galaxy distribution is well
described by a fractal dimension D ~ 2 up to a scale of at least 20 Mpc/h. We
discuss critically the agreement of this new data with current theoretical
models.Comment: 6 pages, 1 figure. Revised version with minor corrections. To be
published in Astronomy and Astrophysic
The WiggleZ Dark Energy Survey: the transition to large-scale cosmic homogeneity
We have made the largest-volume measurement to date of the transition to
large-scale homogeneity in the distribution of galaxies. We use the WiggleZ
survey, a spectroscopic survey of over 200,000 blue galaxies in a cosmic volume
of ~1 (Gpc/h)^3. A new method of defining the 'homogeneity scale' is presented,
which is more robust than methods previously used in the literature, and which
can be easily compared between different surveys. Due to the large cosmic depth
of WiggleZ (up to z=1) we are able to make the first measurement of the
transition to homogeneity over a range of cosmic epochs. The mean number of
galaxies N(<r) in spheres of comoving radius r is proportional to r^3 within
1%, or equivalently the fractal dimension of the sample is within 1% of D_2=3,
at radii larger than 71 \pm 8 Mpc/h at z~0.2, 70 \pm 5 Mpc/h at z~0.4, 81 \pm 5
Mpc/h at z~0.6, and 75 \pm 4 Mpc/h at z~0.8. We demonstrate the robustness of
our results against selection function effects, using a LCDM N-body simulation
and a suite of inhomogeneous fractal distributions. The results are in
excellent agreement with both the LCDM N-body simulation and an analytical LCDM
prediction. We can exclude a fractal distribution with fractal dimension below
D_2=2.97 on scales from ~80 Mpc/h up to the largest scales probed by our
measurement, ~300 Mpc/h, at 99.99% confidence.Comment: 21 pages, 16 figures, accepted for publication in MNRA
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