1,182 research outputs found
AdS_3/CFT_2 Correspondence and Space-Time N=3 Superconformal Algebra
We study a Wess-Zumino-Witten model with target space AdS_3 x (S^3 x S^3 x
S^1)/Z_2. This allows us to construct space-time N=3 superconformal theories.
By combining left-, and right-moving parts through a GSO and a Z_2 projections,
a new asymmetric (N,\bar{N})=(3,1) model is obtained. It has an extra gauge
(affine) SU(2) symmetry in the target space of the type IIA string. An
associated configuration is realized as slantwise intersecting M5-M2 branes
with a Z_2-fixed plane in the M-theory viewpoint.Comment: 27 pages, 1 figure, final versio
Spin Fluid Dynamics Observed by Magnetic Fountain Effect and Mechano-Spin Effect in the Ferromagnetic Superfluid He A Phase
Systematic observations of the magnetically generated fountain pressure in
the superfluid He A have been carried out in a newly built apparatus
designed to reduce the effect of thermal gradients. In the same apparatus,
mechanical pumping and filtering of polarized nuclear spins were realized by
the pneumatic pumping action of an electrostatically actuated membrane. In both
experiments, the measured induced pressure was observed to decay at all
temperatures where the A phase appeared in magnetic fields up to 13 T and
liquid pressures between 1 and 29 bar. The inferred spin relaxation rate tended
to increase as the low temperature phase boundary with the A phase
(T) was approached. The increase in spin relaxation rate near T
can be explained by the presence of a minority spin condensate in the A
phase as predicted by Monien and Tewordt and by the application of the
Leggett-Takagi theory of spin relaxation in superfluid He.Comment: 12 pages, 15 figures, to appear in Physical Review
MRI-based Surgical Planning for Lumbar Spinal Stenosis
The most common reason for spinal surgery in elderly patients is lumbar
spinal stenosis(LSS). For LSS, treatment decisions based on clinical and
radiological information as well as personal experience of the surgeon shows
large variance. Thus a standardized support system is of high value for a more
objective and reproducible decision. In this work, we develop an automated
algorithm to localize the stenosis causing the symptoms of the patient in
magnetic resonance imaging (MRI). With 22 MRI features of each of five spinal
levels of 321 patients, we show it is possible to predict the location of
lesion triggering the symptoms. To support this hypothesis, we conduct an
automated analysis of labeled and unlabeled MRI scans extracted from 788
patients. We confirm quantitatively the importance of radiological information
and provide an algorithmic pipeline for working with raw MRI scans
ChIP-on-chip analysis reveals angiopoietin 2 (Ang2, ANGPT2) as a novel target of steroidogenic factor-1 (SF-1, NR5A1) in the human adrenal gland
The nuclear receptor steroidogenic factor-1 (SF-1, NR5A1) is a key regulator of adrenal and gonadal biology. Disruption of SF-1 can lead to disorders of adrenal development, while increased SF-1 dosage has been associated with adrenocortical tumorigenesis. We aimed to identify a novel subset of SF-1 target genes in the adrenal by using chromatin immunoprecipitation (ChIP) microarrays (ChIP-on-chip) combined with systems analysis. SF-1 ChIP-on-chip was performed in NCI-H295R human adrenocortical cells using promoter tiling arrays, leading to the identification of 445 gene loci where SF-1-binding regions were located from 10 kb upstream to 3 kb downstream of a transcriptional start. Network analysis of genes identified as putative SF-1 targets revealed enrichment for angiogenic process networks. A 1.1-kb SF-1-binding region was identified in the angiopoietin 2 (Ang2, ANGPT2) promoter in a highly repetitive region, and SF-1-dependent activation was confirmed in luciferase assays. Angiogenesis is paramount in adrenal development and tumorigenesis, but until now a direct link between SF-1 and vascular remodeling has not been established. We have identified Ang2 as a potentially important novel target of SF-1 in the adrenal gland, indicating that regulation of angiogenesis might be an important additional mechanism by which SF-1 exerts its actions in the adrenal gland
Polarised target for Drell-Yan experiment in COMPASS at CERN, part I
In the polarised Drell-Yan experiment at the COMPASS facility in CERN pion
beam with momentum of 190 GeV/c and intensity about pions/s interacted
with transversely polarised NH target. Muon pairs produced in Drel-Yan
process were detected. The measurement was done in 2015 as the 1st ever
polarised Drell-Yan fixed target experiment. The hydrogen nuclei in the
solid-state NH were polarised by dynamic nuclear polarisation in 2.5 T
field of large-acceptance superconducting magnet. Large helium dilution
cryostat was used to cool the target down below 100 mK. Polarisation of
hydrogen nuclei reached during the data taking was about 80 %. Two oppositely
polarised target cells, each 55 cm long and 4 cm in diameter were used.
Overview of COMPASS facility and the polarised target with emphasis on the
dilution cryostat and magnet is given. Results of the polarisation measurement
in the Drell-Yan run and overviews of the target material, cell and dynamic
nuclear polarisation system are given in the part II.Comment: 4 pages, 2 figures, Proceedings of the 22nd International Spin
Symposium, Urbana-Champaign, Illinois, USA, 25-30 September 201
Neutron scattering study of magnetic ordering and excitations in the ternary rare-earth diborocarbide Ce^{11}B_2C_2
Neutron scattering experiments have been performed on the ternary rare-earth
diborocarbide CeBC. The powder diffraction experiment confirms
formation of a long-range magnetic order at K, where a
sinusoidally modulated structure is realized with the modulation vector . Inelastic excitation spectra in the
paramagnetic phase comprise significantly broad quasielastic and inelastic
peaks centered at and 65 meV.
Crystalline-electric-field (CEF) analysis satisfactorily reproduces the
observed spectra, confirming their CEF origin. The broadness of the
quasielastic peak indicates strong spin fluctuations due to coupling between
localized spins and conduction electrons in the paramagnetic phase. A
prominent feature is suppression of the quasielastic fluctuations, and
concomitant growth of a sharp inelastic peak in a low energy region below
. This suggests dissociation of the conduction and localized
electrons on ordering, and contrasts the presently observed incommensurate
phase with spin-density-wave order frequently seen in heavy fermion compounds,
such as Ce(RuLa)Si.Comment: accepted for publication in Phys. Rev.
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