69,853 research outputs found
A First Experimental Limit on In-matter Torsion from Neutron Spin Rotation in Liquid He-4
We report the first experimental upper bound to our knowledge on possible
in-matter torsion interactions of the neutron from a recent search for parity
violation in neutron spin rotation in liquid He-4. Our experiment constrains a
coefficient consisting of a linear combination of parameters involving
the time components of the torsion fields and from the nucleons
and electrons in helium which violates parity. We report an upper bound of
GeV at 68% confidence level and indicate other physical
processes that could be analyzed to constrain in-matter torsion.Comment: 12 pages, typo correcte
Recommended from our members
The use of platelet-rich plasma in treatment of olfactory dysfunction: A pilot study.
BackgroundOlfactory dysfunction is a prevalent problem with a significant impact on quality of life and increased mortality. Limited effective therapies exist. Platelet-rich plasma (PRP) is an autologous biologic product with anti-inflammatory and neuroprotective effects. This novel pilot study evaluated the role of PRP on olfactory neuroregeneration in patients with hyposmia.MethodsSeven patients who had olfactory loss greater than 6 months in duration, no evidence of sinonasal inflammatory disease, and no improvement with olfactory training and budesonide topical rinses were enrolled in this preliminary study. Patients received a single intranasal injection of PRP into the mucosa of the olfactory cleft. The Sniffin' Sticks olfactory test consisting of threshold, discrimination, and identification measurements (TDI) was administered at the beginning of the study and at 1 and 3 months.ResultsAll patients reported a subjective improvement of their smell shortly after injection but then stabilized. At 3-month post-treatment, two patients with functional anosmia (TDI < 16) did not improve significantly. Five patients with hyposmia (TDI > 16 but <30) showed an improvement with 60% achieving normosmia (TDI > 30) at 3-month follow-up. On average, patients with baseline TDI > 16 improved by 5.85 points with the most significant improvement in the threshold subcomponent. There were no adverse outcomes from intranasal PRP injections.ConclusionPRP appears safe for use in the treatment of olfactory loss, and preliminary data suggest possible efficacy, especially for those with moderate yet persistent loss. Further studies will help determine optimal frequency and duration of use.Level of evidence 2
Simple ultraviolet-based soft-lithography process for fabrication of low-loss polymer polysiloxanes-based waveguides
A simple ultraviolet (UV)-based soft-lithography process is used for fabrication of polymer polysiloxanes (PSQ-L) waveguides. The imprint process is first done on the cladding PSQ-LL layer and is followed by a spin-coating step to fill the imprinted features with core PSQ-LH layer material. The optical loss of the straight PSQ-L waveguides is characterised by the Fabry-Perot method for the first time. Even with non-polished facet of the waveguide, the Fabry-Perot resonance spectrum is obtained. An upper limit scattering loss of the waveguide is extracted to be less than 0.8 +/- 0.2 dB/cm for TE mode and 1.3 +/- 0.2 dB/cm for TM mode at 1550 nm. The fully transferred pattern and low scattering loss proves it to be an effective way to replicate low-loss polymer PSQ-L-based waveguides
Electron beam profile imaging in the presence of coherent optical radiation effects
High-brightness electron beams with low energy spread at existing and future
x-ray free-electron lasers are affected by various collective beam
self-interactions and microbunching instabilities. The corresponding coherent
optical radiation effects, e.g., coherent optical transition radiation, render
electron beam profile imaging impossible and become a serious issue for all
kinds of electron beam diagnostics using imaging screens. Furthermore, coherent
optical radiation effects can also be related to intrinsically ultrashort
electron bunches or the existence of ultrashort spikes inside the electron
bunches. In this paper, we discuss methods to suppress coherent optical
radiation effects both by electron beam profile imaging in dispersive beamlines
and by using scintillation imaging screens in combination with separation
techniques. The suppression of coherent optical emission in dispersive
beamlines is shown by analytical calculations, numerical simulations, and
measurements. Transverse and longitudinal electron beam profile measurements in
the presence of coherent optical radiation effects in non-dispersive beamlines
are demonstrated by applying a temporal separation technique.Comment: 12 pages, 11 figures, submitted to Phys. Rev. ST Accel. Beam
On determination of the geometric cosmological constant from the OPERA experiment of superluminal neutrinos
The recent OPERA experiment of superluminal neutrinos has deep consequences
in cosmology. In cosmology a fundamental constant is the cosmological constant.
From observations one can estimate the effective cosmological constant
which is the sum of the quantum zero point energy
and the geometric cosmological constant . The
OPERA experiment can be applied to determine the geometric cosmological
constant . It is the first time to distinguish the contributions of
and from each other by experiment. The
determination is based on an explanation of the OPERA experiment in the
framework of Special Relativity with de Sitter space-time symmetry.Comment: 7 pages, no figure
Detections of water ice, hydrocarbons, and 3.3um PAH in z~2 ULIRGs
We present the first detections of the 3um water ice and 3.4um amorphous
hydrocarbon (HAC) absorption features in z~2 ULIRGs. These are based on deep
rest-frame 2-8um Spitzer IRS spectra of 11 sources selected for their
appreciable silicate absorption. The HAC-to-silicate ratio for our z~2 sources
is typically higher by a factor of 2-5 than that observed in the Milky Way.
This HAC `excess' suggests compact nuclei with steep temperature gradients as
opposed to predominantly host obscuration. Beside the above molecular
absorption features, we detect the 3.3um PAH emission feature in one of our
sources with three more individual spectra showing evidence for it. Stacking
analysis suggests that water ice, hydrocarbons, and PAH are likely present in
the bulk of this sample even when not individually detected. The most
unexpected result of our study is the lack of clear detections of the 4.67um CO
gas absorption feature. Only three of the sources show tentative signs of this
feature and at significantly lower levels than has been observed in local
ULIRGs. Overall, we find that the closest local analogs to our sources, in
terms of 3-4um color, HAC-to-silicate and ice-to-silicate ratios, as well as
low PAH equivalent widths are sources dominated by deeply obscured nuclei. Such
sources form only a small fraction of ULIRGs locally and are commonly believed
to be dominated by buried AGN. Our sample suggests that, in absolute number,
such buried AGN are at least an order of magnitude more common at z~2 than
today. The presence of PAH suggests that significant levels of star-formation
are present even if the obscured AGN typically dominate the power budget.Comment: 39 pages, 14 figures, accepted for publication in Ap
- …