2,208 research outputs found
USING NATURE AS BOTH MENTOR AND MODEL: ANIMAL WELFARE RESEARCH AND DEVELOPMENT IN SUSTAINABLE SWINE PRODUCTION
Livestock Production/Industries,
Ensuring a Strong Public Health Workforce for the 21st Century: Reflections on PH WINS 2017
The success of any organization can be attributed to one thing: its people. This is particularly true for local health departments (LHDs) and state health agencies (SHAs), as the public health workforce is fundamental to achieving organizational goals and improving the health outcomes of populations
Anisotropy in the Cosmic Microwave Background at Degree Angular Scales: Python V Results
Observations of the microwave sky using the Python telescope in its fifth
season of operation at the Amundsen-Scott South Pole Station in Antarctica are
presented. The system consists of a 0.75 m off-axis telescope instrumented with
a HEMT amplifier-based radiometer having continuum sensitivity from 37-45 GHz
in two frequency bands. With a 0.91 deg x 1.02 deg beam the instrument fully
sampled 598 deg^2 of sky, including fields measured during the previous four
seasons of Python observations. Interpreting the observed fluctuations as
anisotropy in the cosmic microwave background, we place constraints on the
angular power spectrum of fluctuations in eight multipole bands up to l ~ 260.
The observed spectrum is consistent with both the COBE experiment and previous
Python results. There is no significant contamination from known foregrounds.
The results show a discernible rise in the angular power spectrum from large (l
~ 40) to small (l ~ 200) angular scales. The shape of the observed power
spectrum is not a simple linear rise but has a sharply increasing slope
starting at l ~ 150.Comment: 5 page
Molecular Dynamics Simulation Study of Nonconcatenated Ring Polymers in a Melt: I. Statics
Molecular dynamics simulations were conducted to investigate the structural
properties of melts of nonconcatenated ring polymers and compared to melts of
linear polymers. The longest rings were composed of N=1600 monomers per chain
which corresponds to roughly 57 entanglement lengths for comparable linear
polymers. For the rings, the radius of gyration squared was found to scale as N
to the 4/5 power for an intermediate regime and N to the 2/3 power for the
larger rings indicating an overall conformation of a crumpled globule. However,
almost all beads of the rings are "surface beads" interacting with beads of
other rings, a result also in agreement with a primitive path analysis
performed in the following paper (DOI: 10.1063/1.3587138). Details of the
internal conformational properties of the ring and linear polymers as well as
their packing are analyzed and compared to current theoretical models.Comment: 15 pages, 14 figure
DASI First Results: A Measurement of the Cosmic Microwave Background Angular Power Spectrum
We present measurements of anisotropy in the Cosmic Microwave Background
(CMB) from the first season of observations with the Degree Angular Scale
Interferometer (DASI). The instrument was deployed at the South Pole in the
austral summer 1999--2000, and made observations throughout the following
austral winter. We have measured the angular power spectrum of the CMB in the
range 100<l<900 with high signal-to-noise. In this paper we review the
formalism used in the analysis, in particular the use of constraint matrices to
project out contaminants such as ground and point source signals, and to test
for correlations with diffuse foreground templates. We find no evidence of
foregrounds other than point sources in the data, and find a maximum likelihood
temperature spectral index beta = -0.1 +/- 0.2 (1 sigma), consistent with CMB.
We detect a first peak in the power spectrum at l approx 200, in agreement with
previous experiments. In addition, we detect a peak in the power spectrum at l
approx 550 and power of similar magnitude at l approx 800 which are consistent
with the second and third harmonic peaks predicted by adiabatic inflationary
cosmological models.Comment: 8 pages, 1 figure, minor changes in response to referee comment
Overview of the spectrometer optical fiber feed for the Habitable-zone Planet Finder
The Habitable-zone Planet Finder (HPF) is a highly stabilized fiber fed
precision radial velocity (RV) spectrograph working in the Near Infrared (NIR):
810 - 1280 nm . In this paper we present an overview of the preparation of the
optical fibers for HPF. The entire fiber train from the telescope focus down to
the cryostat is detailed. We also discuss the fiber polishing, splicing and its
integration into the instrument using a fused silica puck. HPF was designed to
be able to operate in two modes, High Resolution (HR- the only mode mode
currently commissioned) and High Efficiency (HE). We discuss these fiber heads
and the procedure we adopted to attach the slit on to the HR fibers.Comment: Presented at 2018 SPIE Astronomical Telescopes + Instrumentation,
Austin, Texas, USA. 18 pages, 25 figures, and 2 table
F-theory and Dark Energy
Motivated by its potential use as a starting point for solving various
cosmological constant problems, we study F-theory compactified on the warped
product where is a
manifold, and the factor is the target space of an
Wess--Zumino--Witten (WZW) model at level . Reduction to M-theory exploits
the abelian duality of this WZW model to an orbifold. In
the large limit, the untwisted sector is captured by 11D supergravity. The
local dynamics of intersecting 7-branes in the geometry is controlled
by a Donaldson--Witten twisted gauge theory coupled to defects. At late times,
the system is governed by a 1D quantum mechanics system with a ground state
annihilated by two real supercharges, which in four dimensions would appear as
" supersymmetry" on a curved background. This leads to a
cancellation of zero point energies in the 4D field theory but a split mass
spectrum for superpartners of order specified by the IR and UV cutoffs of the model. This is
suggestively close to the TeV scale in some scenarios. The classical 4D
geometry has an intrinsic instability which can produce either a collapsing or
expanding Universe, the latter providing a promising starting point for a
number of cosmological scenarios. The resulting 1D quantum mechanics in the
time direction also provides an appealing starting point for a more detailed
study of quantum cosmology.Comment: v3: 67 pages, 5 figures, reference added, typos corrected, revised
analysis of superpartner masse
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