588 research outputs found
Human Apolipoprotein B Transgenic Mice Generated with 207- and 145-Kilobase Pair Bacterial Artificial Chromosomes. Evidence that a distant 5'-element confers appropriate transgene expression in the intestine
We reported previously that ~80-kilobase pair (kb) P1 bacteriophage clones spanning either the human or mouse apoB gene (clones p158 and p649, respectively) confer apoB expression in the liver of transgenic mice, but not in the intestine. We hypothesized that the absence of intestinal expression was due to the fact that these clones lacked a distant DNA element controlling intestinal expression. To test this possibility, transgenic mice were generated with 145- and 207-kb bacterial artificial chromosomes (BACs) that contained the human apoB gene and more extensive 5'- and 3'-flanking sequences. RNase protection, in situ hybridization, immunohistochemical, and genetic complementation studies revealed that the BAC transgenic mice manifested appropriate apoB gene expression in both the intestine and the liver, indicating that both BACs contained the distant intestinal element. To determine whether the regulatory element was located 5' or 3' to the apoB gene, transgenic mice were generated by co-microinjecting embryos with p158 and either the 5'- or 3'-sequences from the 145-kb BAC. Analysis of these mice indicated that the apoB gene's intestinal element is located 5' to the structural gene. Cumulatively, the transgenic mouse studies suggest that the intestinal element is located between -33 and -70 kb 5' to the apoB gene
The Ignatian Pedagogy Paradigm and the Global Imperative of Biotechnology
The potential of the Ignatian Pedagogical Paradigm (IPP) is realized in the reflective actions of students after they leave the Jesuit educational setting and go out into the world. With developments in science and technology accelerating, and worldwide dissemination immediate, the imperative to infuse the IPP into areas driven by science and technology is clear. It is this imperative which draws us to the global biotechnology industry. This paper presents a short overview of the industry, describes how âscience-businessâ differs from traditional business, and discusses the process by which the IPP â context, experience, reflection, action and evaluation â has been developed in the Business of Biotechnology program at the University of San Francisco (USF). The cases developed to exemplify the IPP are âOrganized Religion and the Business of Biotechnology,â âHumanist Measures for Success in Bio-Business,â and âThe Poor and Marginalized.â In addition, the Business of Biotechnology program utilizes the Biotechnology Innovation Expertise Model (BIEM 2.0), which identifies a recognized complement of the disciplines needed to bring breakthrough bioscience to a commercial product. These disciplines are readily present at Jesuit universities, which can, in turn, directly support education of value to the global biotechnology industry
Caribou and reindeer migrations in the changing Arctic
Caribou and reindeer, Rangifer tarandus, are the most numerous and socio-ecologically important terrestrial species in the Arctic. Their migrations are directly and indirectly affected by the seasonal nature of the northernmost regions, human development and population size; all of which are impacted by climate change. We review the most critical drivers of Rangifer migration and how a rapidly changing Arctic may affect them. In order to conserve large Rangifer populations, they must be allowed free passage along their migratory routes to reach seasonal ranges. We also provide some pragmatic ideas to help conserve Rangifer migrations into the future. Barrier effect, Climate change, Connectivity, Conservation, Development, Mitigation, RangiferpublishedVersio
Selection and photometric properties of K+A galaxies
Two different simple measurements of galaxy star formation rate with
different timescales are compared empirically on fiber spectra of
galaxies with mag taken from the Sloan Digital Sky Survey in the
redshift range : a ratio \Aamp / \Kamp found by fitting a linear
sum of an average old stellar poplulation spectrum (\Kamp) and average A-star
spectrum (\Aamp) to the galaxy spectrum, and the equivalent width (EW) of the
\Halpha emission line. The two measures are strongly correlated, but there is
a small clearly separated population of outliers from the median correlation
that display excess \Aamp /\Kamp relative to \Halpha EW. These ``K+A'' (or
``E+A'') galaxies must have dramatically decreased their star-formation rates
over the last Gyr. The K+A luminosity distribution is very similar to
that of the total galaxy population. The K+A population appears to be
bulge-dominated, but bluer and higher surface-brightness than normal
bulge-dominated galaxies; it appears that K+A galaxies will fade with time into
normal bulge-dominated galaxies. The inferred rate density for K+A galaxy
formation is at redshift .
These events are taking place in the field; K+A galaxies don't primarily lie in
the high-density environments or clusters typical of bulge-dominated
populations.Comment: submitted to Ap
Increased parental effort fails to buffer the cascading effects of warmer seas on common guillemot demographic rates
Research Funding Natural Environment Research Council Award. Grant Number: NE/R016429/1 UK-SCAPE Programme Delivering National Capability Joint Nature Conservation Committee EU âThe Effect of Large-scale Industrial Fisheries On Non-Target Speciesâ FP5 Project âInteractions between the Marine environment, PREdators and Prey: Implications for Sustainable Sandeel Fisheriesâ. Grant Numbers: MS21-013, Q5RS-2000-30864 Ministry of Universities-University of ValenciaPeer reviewedPublisher PD
Discovery of Four Gravitationally Lensed Quasars from the Sloan Digital Sky Survey
We present the discovery of four gravitationally lensed quasars selected from
the spectroscopic quasar catalog of the Sloan Digital Sky Survey. We describe
imaging and spectroscopic follow-up observations that support the lensing
interpretation of the following four quasars: SDSS J0832+0404 (image separation
\theta=1.98", source redshift z_s=1.115, lens redshift z_l=0.659); SDSS
J1216+3529 (\theta=1.49", z_s=2.012); SDSS J1322+1052 (\theta=2.00",
z_s=1.716); and SDSS J1524+4409 (\theta=1.67", z_s=1.210, z_l=0.320). Each
system has two lensed images. We find that the fainter image component of SDSS
J0832+0404 is significantly redder than the brighter component, perhaps because
of differential reddening by the lensing galaxy. The lens potential of SDSS
J1216+3529 might be complicated by the presence of a secondary galaxy near the
main lensing galaxy.Comment: 25 pages, 10 figures, 6 tables, accepted for publication in A
Detectors and cryostat design for the SuMIRe Prime Focus Spectrograph (PFS)
We describe the conceptual design of the camera cryostats, detectors, and
detector readout electronics for the SuMIRe Prime Focus Spectrograph (PFS)
being developed for the Subaru telescope. The SuMIRe PFS will consist of four
identical spectrographs, each receiving 600 fibers from a 2400 fiber robotic
positioner at the prime focus. Each spectrograph will have three channels
covering wavelength ranges 3800 {\AA} - 6700 {\AA}, 6500 {\AA} - 10000 {\AA},
and 9700 {\AA} - 13000 {\AA}, with the dispersed light being imaged in each
channel by a f/1.10 vacuum Schmidt camera. In the blue and red channels a pair
of Hamamatsu 2K x 4K edge-buttable CCDs with 15 um pixels are used to form a 4K
x 4K array. For the IR channel, the new Teledyne 4K x 4K, 15 um pixel,
mercury-cadmium-telluride sensor with substrate removed for short-wavelength
response and a 1.7 um cutoff will be used. Identical detector geometry and a
nearly identical optical design allow for a common cryostat design with the
only notable difference being the need for a cold radiation shield in the IR
camera to mitigate thermal background. This paper describes the details of the
cryostat design and cooling scheme, relevant thermal considerations and
analysis, and discusses the detectors and detector readout electronics
Variable Point Sources in Sloan Digital Sky Survey Stripe 82. I. Project Description and Initial Catalog (0 h < R.A. < 4 h)
We report the first results of a study of variable point sources identified
using multi-color time-series photometry from Sloan Digital Sky Survey (SDSS)
Stripe 82 over a span of nearly 10 years (1998-2007). We construct a
light-curve catalog of 221,842 point sources in the R.A. 0-4 h half of Stripe
82, limited to r = 22.0, that have at least 10 detections in the ugriz bands
and color errors of < 0.2 mag. These objects are then classified by color and
by cross-matching them to existing SDSS catalogs of interesting objects. We use
inhomogeneous ensemble differential photometry techniques to greatly improve
our sensitivity to variability. Robust variable identification methods are used
to extract 6520 variable candidates in this dataset, resulting in an overall
variable fraction of ~2.9% at the level of 0.05 mag variability. A search for
periodic variables results in the identification of 30 eclipsing/ellipsoidal
binary candidates, 55 RR Lyrae, and 16 Delta Scuti variables. We also identify
2704 variable quasars matched to the SDSS Quasar catalog (Schneider et al.
2007), as well as an additional 2403 quasar candidates identified by their
non-stellar colors and variability properties. Finally, a sample of 11,328
point sources that appear to be nonvariable at the limits of our sensitivity is
also discussed. (Abridged.)Comment: 67 pages, 27 figures. Accepted for publication in ApJS. Catalog
available at http://shrike.pha.jhu.edu/stripe82-variable
First Structure Formation: I. Primordial Star Forming Regions in hierarchical models
We investigate the possibility of very early formation of primordial star
clusters from high-\sigma perturbations in cold dark matter dominated structure
formation scenarios. For this we have developed a powerful 2-level hierarchical
cosmological code with a realistic and robust treatment of multi-species
primordial gas chemistry, paying special attention to the formation and
destruction of hydrogen molecules, non-equilibrium ionization, and cooling
processes. We performed 3-D simulations at small scales and at high redshifts
and find that, analogous to simulations of large scale structure, a complex
system of filaments, sheets, and spherical knots at the intersections of
filaments form. On the mass scales covered by our simulations (5x10^5 -
1x10^9\Ms) that collapse at redshifts z>25, we find that only at the spherical
knots can enough H2 be formed (n_{H_2}/n_H > 5x10^-4) to cool the gas
appreciably. Quantities such as the time dependence of the formation of H2
molecules, the final H2 fraction, and central densities from the simulations
are compared to the theoretical predictions of Abel (1995) and Tegmark et al.
(1997) and found to agree remarkably well. Comparing the 3-D results to an
isobaric collapse model we further discuss the possible implications of the
extensive merging of small structure that is inherent in hierarchical models.
Typically only 5-8% percent of the total baryonic mass in the collapsing
structures is found to cool significanlty. Assuming the Padoan (1995) model for
star formation our results would predict the first stellar systems to be as
small as ~30\Ms. Some implications for primordial globular cluster formation
scenarios are also discussed.Comment: 22 pages, 13 Figures. Submitted to ApJ. Laboratory for Computational
Astrophysics at the National Center for Supercomputing Application
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