4,796 research outputs found
History of Law Clas of 1883 of Michigan University
The origin of this book, which is a new departure, and ever to be remembered as a production of the La.w Class of 1883 of the Michigan University, without a precedent from which to conceive its peculiarities of style, is as follows: In a convention he
Recursion-free solution for two-loop vacuum integrals with "collinear" masses
We investigate the structure of a particular class of massive vacuum Feynman
integrals at two loops. This class enjoys the linear relation
between its three propagator masses, corresponding to zeros of the associated
K\"all\'en function. Apart from having applications in thermal field theory,
the integrals can be mapped onto one-loop three-point functions with collinear
external momenta, suggesting the term "collinear" masses. We present a
closed-form solution for these integrals, proving that they can always be
factorized into products of one-loop cases, for all integer-valued propagator
powers.Comment: 34 pages, 5 figures; v2: references adde
Does environment affect the star formation histories of early-type galaxies?
Differences in the stellar populations of galaxies can be used to quantify
the effect of environment on the star formation history. We target a sample of
early-type galaxies from the Sloan Digital Sky Survey in two different
environmental regimes: close pairs and a general sample where environment is
measured by the mass of their host dark matter halo. We apply a blind source
separation technique based on principal component analysis, from which we
define two parameters that correlate, respectively, with the average stellar
age (eta) and with the presence of recent star formation (zeta) from the
spectral energy distribution of the galaxy. We find that environment leaves a
second order imprint on the spectra, whereas local properties - such as
internal velocity dispersion - obey a much stronger correlation with the
stellar age distribution.Comment: 5 pages, 2 figures. Proceedings of JENAM 2010, Symposium 2:
"Environment and the formation of galaxies: 30 years later
A catalogue of absorption-line systems in QSO spectra
We present a new catalog of absprption-line systems identified in the quasar
spectra. It contains data on 821 QSOs and 8558 absorption systems comprizing
16139 absorption lines with measured redshifts in the QSO spectra. The catalog
includes absorption-line systems consisting of lines of heavy elements, lines
of neutral hydrogen, Lyman limit systems, damped Ly\alpha absorption systems,
and broad absorption-line systems. The catalog is available in electronic form
at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via
http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/412/707 and at
www.ioffe.ru/astro/QC. Using the data of the present catalog we also discuss
redshift distributions of absorption-line systems.Comment: 3 pages with 1 postscript figur
Uncle Tom\u27s Lament for Eva / words by I. B. Woodbury
Cover: He strikes his harp immortal. To Evas gentle song.; Publisher: Oliver Ditson (New York)https://egrove.olemiss.edu/sharris_a/1005/thumbnail.jp
Three-Dimensional Gravity and String Ghosts
It is known that much of the structure of string theory can be derived from
three-dimensional topological field theory and gravity. We show here that, at
least for simple topologies, the string diffeomorphism ghosts can also be
explained in terms of three-dimensional physics.Comment: 6 page
Receipt from Holland Society of New York to Ogden Goelet
https://digitalcommons.salve.edu/goelet-personal-expenses/1035/thumbnail.jp
Rare mutations and potentially damaging missense variants in genes encoding fibrillar collagens and proteins involved in their production are candidates for risk for preterm premature rupture of membranes
Preterm premature rupture of membranes (PPROM) is the leading identifiable cause of preterm birth with ~ 40% of preterm births being associated with PPROM and occurs in 1% - 2% of all pregnancies. We hypothesized that multiple rare variants in fetal genes involved in extracellular matrix synthesis would associate with PPROM, based on the assumption that impaired elaboration of matrix proteins would reduce fetal membrane tensile strength, predisposing to unscheduled rupture. We performed whole exome sequencing (WES) on neonatal DNA derived from pregnancies complicated by PPROM (49 cases) and healthy term deliveries (20 controls) to identify candidate mutations/variants. Genotyping for selected variants from the WES study was carried out on an additional 188 PPROM cases and 175 controls. All mothers were self-reported African Americans, and a panel of ancestry informative markers was used to control for genetic ancestry in all genetic association tests. In support of the primary hypothesis, a statistically significant genetic burden (all samples combined, SKAT-O p-value = 0.0225) of damaging/potentially damaging rare variants was identified in the genes of interest—fibrillar collagen genes, which contribute to fetal membrane strength and integrity. These findings suggest that the fetal contribution to PPROM is polygenic, and driven by an increased burden of rare variants that may also contribute to the disparities in rates of preterm birth among African Americans
The Mean Metal-line Absorption Spectrum of DLAs in BOSS
We study the mean absorption spectrum of the Damped Lyman alpha population at
by stacking normalized, rest-frame shifted spectra of DLAs from the DR12 of BOSS/SDSS-III. We measure the equivalent widths
of 50 individual metal absorption lines in 5 intervals of DLA hydrogen column
density, 5 intervals of DLA redshift, and overall mean equivalent widths for an
additional 13 absorption features from groups of strongly blended lines. The
mean equivalent width of low-ionization lines increases with ,
whereas for high-ionization lines the increase is much weaker. The mean metal
line equivalent widths decrease by a factor from to
, with small or no differences between low- and high-ionization
species. We develop a theoretical model, inspired by the presence of multiple
absorption components observed in high-resolution spectra, to infer mean metal
column densities from the equivalent widths of partially saturated metal lines.
We apply this model to 14 low-ionization species and to AlIII, SIII, SiIII,
CIV, SiIV, NV and OVI. We use an approximate derivation for separating the
equivalent width contributions of several lines to blended absorption features,
and infer mean equivalent widths and column densities from lines of the
additional species NI, ZnII, CII, FeIII, and SIV. Several of these mean
column densities of metal lines in DLAs are obtained for the first time; their
values generally agree with measurements of individual DLAs from
high-resolution, high signal-to-noise ratio spectra when they are available.Comment: Resubmitted after referee revision. Added evolution of metal-line
equivalent widths with redshift (Section 5). Added assessment of result
dependencies on sample and methodology. Comparison of relative abundances of
DLAs vs Milky Way ISM and halo (Figure 16). Publicly available videos of
composite quasar and DLA spectra realizations here:
https://github.com/lluism
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