2,203 research outputs found
Dr. Harold C. Smith Fund of Ursinus College Official Prospectus, May 2, 2017
This prospectus contains investment strategy and performance for the following stocks in the managed fund: Enanta Pharmaceuticals, Garmin Ltd., Pioneer Natural Resources and WalMart Stores, Inc
Dr. Harold C. Smith Fund of Ursinus College Official Prospectus, November 28, 2017
This prospectus contains investment strategy and performance for the following stocks in the managed fund: Garmin Ltd., Masimo, Micron Technology, Stoneridge and WalMart Stores, Inc
Towards the F-Theorem: N=2 Field Theories on the Three-Sphere
For 3-dimensional field theories with {\cal N}=2 supersymmetry the Euclidean
path integrals on the three-sphere can be calculated using the method of
localization; they reduce to certain matrix integrals that depend on the
R-charges of the matter fields. We solve a number of such large N matrix models
and calculate the free energy F as a function of the trial R-charges consistent
with the marginality of the superpotential. In all our {\cal N}=2
superconformal examples, the local maximization of F yields answers that scale
as N^{3/2} and agree with the dual M-theory backgrounds AdS_4 x Y, where Y are
7-dimensional Sasaki-Einstein spaces. We also find in toric examples that local
F-maximization is equivalent to the minimization of the volume of Y over the
space of Sasakian metrics, a procedure also referred to as Z-minimization.
Moreover, we find that the functions F and Z are related for any trial
R-charges. In the models we study F is positive and decreases along RG flows.
We therefore propose the "F-theorem" that we hope applies to all 3-d field
theories: the finite part of the free energy on the three-sphere decreases
along RG trajectories and is stationary at RG fixed points. We also show that
in an infinite class of Chern-Simons-matter gauge theories where the
Chern-Simons levels do not sum to zero, the free energy grows as N^{5/3} at
large N. This non-trivial scaling matches that of the free energy of the
gravity duals in type IIA string theory with Romans mass.Comment: 66 pages, 10 figures; v2: refs. added, minor improvement
Zebrafish TRPA1 Channels Are Required for Chemosensation But Not for Thermosensation or Mechanosensory Hair Cell Function
Transient receptor potential (TRP) ion channels have been implicated in detecting chemical, thermal, and mechanical stimuli in organisms ranging from mammals to Caenorhabditis elegans. It is well established that TRPA1 detects and mediates behavioral responses to chemical irritants. However, the role of TRPA1 in detecting thermal and mechanical stimuli is controversial. To further clarify the functions of TRPA1 channels in vertebrates, we analyzed their roles in zebrafish. The two zebrafish TRPA1 paralogs are expressed in sensory neurons and are activated by several chemical irritants in vitro. High-throughput behavioral analyses of trpa1a and trpa1b mutant larvae indicate that TRPA1b is necessary for behavioral responses to these chemical irritants. However, TRPA1 paralogs are not required for behavioral responses to temperature changes or for mechanosensory hair cell function in the inner ear or lateral line. These results support a role for zebrafish TRPA1 in chemical but not thermal or mechanical sensing, and establish a high-throughput system to identify genes and small molecules that modulate chemosensation, thermosensation, and mechanosensation
Entanglement Entropy of 3-d Conformal Gauge Theories with Many Flavors
Three-dimensional conformal field theories (CFTs) of deconfined gauge fields
coupled to gapless flavors of fermionic and bosonic matter describe quantum
critical points of condensed matter systems in two spatial dimensions. An
important characteristic of these CFTs is the finite part of the entanglement
entropy across a circle. The negative of this quantity is equal to the finite
part of the free energy of the Euclidean CFT on the three-sphere, and it has
been proposed to satisfy the so called F-theorem, which states that it
decreases under RG flow and is stationary at RG fixed points. We calculate the
three-sphere free energy of non-supersymmetric gauge theory with a large number
N_F of bosonic and/or fermionic flavors to the first subleading order in 1/N_F.
We also calculate the exact free energies of the analogous chiral and
non-chiral {\cal N} = 2 supersymmetric theories using localization, and find
agreement with the 1/N_F expansion. We analyze some RG flows of supersymmetric
theories, providing further evidence for the F-theorem.Comment: 31 pages, 2 figures; v2 refs added, minor change
F-Theorem without Supersymmetry
The conjectured F-theorem for three-dimensional field theories states that
the finite part of the free energy on S^3 decreases along RG trajectories and
is stationary at the fixed points. In previous work various successful tests of
this proposal were carried out for theories with {\cal N}=2 supersymmetry. In
this paper we perform more general tests that do not rely on supersymmetry. We
study perturbatively the RG flows produced by weakly relevant operators and
show that the free energy decreases monotonically. We also consider large N
field theories perturbed by relevant double trace operators, free massive field
theories, and some Chern-Simons gauge theories. In all cases the free energy in
the IR is smaller than in the UV, consistent with the F-theorem. We discuss
other odd-dimensional Euclidean theories on S^d and provide evidence that
(-1)^{(d-1)/2} \log |Z| decreases along RG flow; in the particular case d=1
this is the well-known g-theorem.Comment: 34 pages, 2 figures; v2 refs added, minor improvements; v3 refs
added, improved section 4.3; v4 minor improvement
13kW Advanced Electric Propulsion Flight System Development and Qualification
The next phase of robotic and human deep space exploration missions is enhanced by high performance, high power solar electric propulsion systems for large-scale science missions and cargo transportation. Aerojet Rocketdynes Advanced Electric Propulsion System (AEPS) program is completing development, qualification and delivery of five flight 13.3kW EP systems to NASA. The flight AEPS includes a magnetically-shielded, long-life Hall thruster, power processing unit (PPU), xenon flow controller (XFC), and intrasystem harnesses. The Hall thruster, originally developed and demonstrated by NASAs Glenn Research Center and the Jet Propulsion Laboratory, operates at input powers up to 12.5kW while providing a specific impulse over 2600s at an input voltage of 600V. The power processor is designed to accommodate an input voltage range of 95 to 140V, consistent with operation beyond the orbit of Mars. The integrated system is continuously throttleable between 3 and 13.3kW. The program has completed the system requirement review; the system, thruster, PPU and XFC preliminary design reviews; development of engineering models, and initial system integration testing. This paper will present the high power AEPS capabilities, overall program and design status and the latest test results for the 13.3kW flight system development and qualification program
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