11,531 research outputs found
Super-lattice, rhombus, square, and hexagonal standing waves in magnetically driven ferrofluid surface
Standing wave patterns that arise on the surface of ferrofluids by (single
frequency) parametric forcing with an ac magnetic field are investigated
experimentally. Depending on the frequency and amplitude of the forcing, the
system exhibits various patterns including a superlattice and subharmonic
rhombuses as well as conventional harmonic hexagons and subharmonic squares.
The superlattice arises in a bicritical situation where harmonic and
subharmonic modes collide. The rhombic pattern arises due to the non-monotonic
dispersion relation of a ferrofluid
Excited states of a dilute Bose-Einstein condensate in a harmonic trap
The low-lying hydrodynamic normal modes of a dilute Bose-Einstein gas in an
isotropic harmonic trap determine the corresponding Bogoliubov amplitudes. In
the Thomas-Fermi limit, these modes have large low-temperature occupation
numbers, and they permit an explicit construction of the dynamic structure
function . The total noncondensate number at zero
temperature increases like , where is the condensate radius measured
in units of the oscillator length. The lowest dipole modes are constructed
explicitly in the Bogoliubov approximation.Comment: 15 pages, REVTE
A Dual-polarized Broadband Planar Antenna and Channelizing Filter Bank for Millimeter Wavelengths
We describe the design, fabrication, and testing of a broadband log-periodic
antenna coupled to multiple cryogenic bolometers. This detector architecture,
optimized here for astrophysical observations, simultaneously receives two
linear polarizations with two octaves of bandwidth at millimeter wavelengths.
The broad bandwidth signal received by the antenna is divided into sub-bands
with integrated in-line frequency-selective filters. We demonstrate two such
filter banks: a diplexer with two sub-bands and a log-periodic channelizer with
seven contiguous sub-bands. These detectors have receiver efficiencies of
20-40% and percent level polarization isolation. Superconducting
transition-edge sensor bolometers detect the power in each sub-band and
polarization. We demonstrate circularly symmetric beam patterns, high
polarization isolation, accurately positioned bands, and high optical
efficiency. The pixel design is applicable to astronomical observations of
intensity and polarization at millimeter through sub-millimeter wavelengths. As
compared with an imaging array of pixels measuring only one band, simultaneous
measurements of multiple bands in each pixel has the potential to result in a
higher signal-to-noise measurement while also providing spectral information.
This development facilitates compact systems with high mapping speeds for
observations that require information in multiple frequency bands.Comment: 4 pages, 4 figures, accepted for publication in Applied Physics
Letter
Roper Resonance and S_{11}(1535) from Lattice QCD
Using the constrained curve fitting method and overlap fermions with the
lowest pion mass at , we observe that the masses of the first
positive and negative parity excited states of the nucleon tend to cross over
as the quark masses are taken to the chiral limit. Both results at the physical
pion mass agree with the experimental values of the Roper resonance
() and (). This is seen for the first
time in a lattice QCD calculation. These results are obtained on a quenched
Iwasaki lattice with . We also extract the
ghost states (a quenched artifact) which are shown to decouple from
the nucleon interpolation field above . From the
quark mass dependence of these states in the chiral region, we conclude that
spontaneously broken chiral symmetry dictates the dynamics of light quarks in
the nucleon.Comment: 10 pages, 5 figures, revised version to appear in PL
The androgen receptor and signal-transduction pathways in hormone-refractory prostate cancer. Part 2: androgen-receptor cofactors and bypass pathways
Prostate cancer is the second leading cause of cancer related deaths in men from the western world. Treatment of prostate cancer has relied on androgen deprivation therapy for the past 50 years. Response rates are initially high (70-80%), however almost all patients develop androgen escape and subsequently die within 1-2 years. Unlike breast cancer, alternative approaches (chemotherapy and radiotherapy) do not increase survival time. The high rate of prostate cancer mortality is therefore strongly linked to both development of androgen escape and the lack of alternate therapies. AR mutations and amplifications can not explain all cases of androgen escape and post-translational modification of the AR has become an alternative theory. However recently it has been suggested that AR co-activators e.g. SRC-1 or pathways the bypass the AR (Ras/MAP kinase or PI3K/Akt) may stimulated prostate cancer progression independent of the AR. This review will focus on how AR coactivators may act to increase AR transactivation during sub-optimal DHT concentrations and
also how signal transduction pathways may promote androgen escape via activation of transcription factors, e.g. AP-1, c-Myc and Myb, that induce cell proliferation or inhibit apoptosis
Path Integrals in Polar Field Variables in QFT
We show how to transform a -dimensional Euclidean path integral in terms
of two (Cartesian) fields to a path integral in terms of polar field variables.
First we present a conjecture that states how this transformation should be
done. Then we show that this conjecture is correct in the case of two toy
models. Finally the conjecture will be proven for a general QFT model with two
fields
A comparative study of selected sorbents for sampling of aromatic VOCs from indoor air
Indoor air canbecome pollutedwith VOCs, and understanding the factors which affect adsorption of VOCs from indoor air is important for: (i) the accurate measurement of VOCs, and (ii) to apply mitigation strategies when high analyte concentrations are measured. In this study four VOCs (toluene, ethylbenzene, cumene and dichlorobenzene) were generated as a constant and controlled polluted air stream of VOCs from a dynamic atmospheric chamber. The effects of relative humidity, and sampling flow rate, on adsorption onto Tenax TA and the relatively new silica adsorbents SBA-15 or MCM-41 were studied
A pragmatic randomised controlled trial of healing therapy in a gastroenterology outpatient setting
Introduction:
To determine the benefits of healing therapy (spiritual healing) as an adjunct to conventional management in irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD).
Methods:
200 outpatients with IBS or IBD were randomised to either conventional treatment (control) or conventional plus five sessions of healing therapy (intervention). After 12 weeks controls also had healing therapy. Outcomes used were, the Measure Yourself Medical Outcomes Profile (MYMOP). IBS-QOL, IBDQ, and symptom measures.
Results:
There was a significant improvement in the MYMOP score at week 6 (p < 0.001) which was maintained to week 12 (p < 0.001) and 24 (p < 0.001). Improvements in MYMOP were significantly greater in the intervention group at both 6 (p < 0.001) and 12 weeks (p < 0.001) with effect sizes of 0.7 (95% CI: 0.4–1.1) and 0.8 (95% CI: 0.4–1.2). Condition-specific data for IBS showed that most QoL dimensions had a significant minimum 10-point score improvement at 6 and 12 weeks. The overall score improvement was 12.9 units at week 6 (p < 0.001), 12.4 units at week 12 (p < 0.001) and 13.8 units at week 24 (p < 0.001). In IBD there was also similar score improvement, but only up to week 12 were there associations of improved social and bowel functions (p < 0.001, respectively). Between group differences were identified for QoL scores in IBS at both week 6 (p < 0.001) and 12 (p < 0.001) but only for week 12 (p < 0.001) in the IBD group.
Conclusions:
The addition of healing therapy to conventional treatment was associated with improvement in symptoms and QoL in IBS, and to a lesser extent in IBD
Theory Support for the Excited Baryon Program at the Jlab 12 GeV Upgrade
This document outlines major directions in theoretical support for the
measurement of nucleon resonance transition form factors at the JLab 12 GeV
upgrade with the CLAS12 detector. Using single and double meson production,
prominent resonances in the mass range up to 2 GeV will be studied in the range
of photon virtuality up to 12 GeV where quark degrees of freedom are
expected to dominate. High level theoretical analysis of these data will open
up opportunities to understand how the interactions of dressed quarks create
the ground and excited nucleon states and how these interactions emerge from
QCD. The paper reviews the current status and the prospects of QCD based model
approaches that relate phenomenological information on transition form factors
to the non-perturbative strong interaction mechanisms, that are responsible for
resonance formation.Comment: 52 pages, 19 figures, White Paper of the Electromagnetic N-N*
Transition Form Factor Workshop at Jefferson Lab, October 13-15, 2008,
Newport News, VA, US
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