450 research outputs found
New Limits on the Polarized Anisotropy of the Cosmic Microwave Background at Subdegree Angular Scales
We update the limit from the 90 GHz PIQUE ground-based polarimeter on the
magnitude of any polarized anisotropy of the cosmic microwave radiation. With a
second year of data, we have now limited both Q and U on a ring of 1 degree
radius. The window functions are broad: for E-mode polarization, the effective
l is = 191 +143 -132. We find that the E-mode signal can be no greater than
8.4 microK (95% CL), assuming no B-mode polarization. Limits on a possible
B-mode signal are also presented.Comment: 4 pages, 3 figures, submitted to Astrophysical Journal Letter
CP Violation
Three possibilities for the origin of CP violation are discussed: (1) the
Standard Model in which all CP violation is due to one parameter in the CKM
matrix, (2) the superweak model in which all CP violation is due to new physics
and (3) the Standard Model plus new physics. A major goal of B physics is to
distinguish these possibilities. CP violation implies time reversal violation
(TRV) but direct evidence for TRV is difficult to obtain.Comment: 13 pages, to be published in Lecture Notes of TASI-2000, edited by
Jonathan L. Rosner, World Scientific, 200
Decay-Time Asymmetries at the B-Factories
Absract (Invited talk at the X DAE High Energy Physics symposium in December
1992, held at Tata Institute of Fundamental Research, Bombay)Comment: 20pages, TIFR/TH/93-1
A Limit on the Polarized Anisotropy of the Cosmic Microwave Background at Subdegree Angular Scales
A ground-based polarimeter, PIQUE, operating at 90 GHz has set a new limit on
the magnitude of any polarized anisotropy in the cosmic microwave background.
The combination of the scan strategy and full width half maximum beam of 0.235
degrees gives broad window functions with average multipoles, l = 211+294-146
and l = 212+229-135 for the E- and B-mode window functions, respectively. A
joint likelihood analysis yields simultaneous 95% confidence level flat band
power limits of 14 and 13 microkelvin on the amplitudes of the E- and B-mode
angular power spectra, respectively. Assuming no B-modes, a 95% confidence
limit of 10 microkelvin is placed on the amplitude of the E-mode angular power
spectrum alone.Comment: 4 pages, 3 figures, submitted to Astrophysical Journal Letter
New Measurements of Fine-Scale CMB Polarization Power Spectra from CAPMAP at Both 40 and 90 GHz
We present new measurements of the cosmic microwave background (CMB)
polarization from the final season of the Cosmic Anisotropy Polarization MAPper
(CAPMAP). The data set was obtained in winter 2004-2005 with the 7 m antenna in
Crawford Hill, New Jersey, from 12 W-band (84-100 GHz) and 4 Q-band (36-45 GHz)
correlation polarimeters with 3.3' and 6.5' beamsizes, respectively. After
selection criteria were applied, 956 (939) hours of data survived for analysis
of W-band (Q-band) data. Two independent and complementary pipelines produced
results in excellent agreement with each other. A broad suite of null tests as
well as extensive simulations showed that systematic errors were minimal, and a
comparison of the W-band and Q-band sky maps revealed no contamination from
galactic foregrounds. We report the E-mode and B-mode power spectra in 7 bands
in the range 200 < l < 3000, extending the range of previous measurements to
higher l. The E-mode spectrum, which is detected at 11 sigma significance, is
in agreement with cosmological predictions and with previous work at other
frequencies and angular resolutions. The BB power spectrum provides one of the
best limits to date on B-mode power at 4.8 uK^2 (95% confidence).Comment: 19 pages, 17 figures, 2 tables, submitted to Ap
Demonstration of K-Kbar, B-Bbar, and D-Dbar Transitions with a Pair of Coupled Pendula
A setup of two coupled and damped pendula is used to demonstrate the main
features of transitions beween neutral K, D, B mesons and their respective
antiparticles, including CP violation in K Kbar transitions. The transitions
are described by two-state Schr\"odinger equations. Since the real parts of
their solutions obey the same differential equations as the pendula
coordinates, the pendulum motions can be used to represent the meson
transitions. Video clips of the motions are attached as supplementary material.Comment: 15 pages, 6 figure
Strong rescattering in K-> 3pi decays and low-energy meson dynamics
We present a consistent analysis of final state interactions in
decays in the framework of Chiral Perturbation Theory.
The result is that the kinematical dependence of the rescattering phases cannot
be neglected. The possibility of extracting the phase shifts from future
interference experiments is also analyzed.Comment: 14 pages in RevTex, 3 figures in postscrip
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Epidural Electrical Stimulation for Stroke Rehabilitation: Results of the Prospective, Multicenter, Randomized, Single-Blinded Everest Trial.
BackgroundThis prospective, single-blinded, multicenter study assessed the safety and efficacy of electrical epidural motor cortex stimulation (EECS) in improving upper limb motor function of ischemic stroke patients with moderate to moderately severe hemiparesis.MethodsPatients â„ 4 months poststroke were randomized 2:1 to an investigational (n = 104) or control (n = 60) group, respectively. Investigational patients were implanted (n = 94) with an epidural 6-contact lead perpendicular to the primary motor cortex and a pulse generator. Both groups underwent 6 weeks of rehabilitation, but EECS was delivered to investigational patients during rehabilitation. The primary efficacy endpoint (PE) was defined as attaining a minimum improvement of 4.5 points in the upper extremity Fugl-Meyer (UEFM) scale as well as 0.21 points in the Arm Motor Ability Test (AMAT) 4 weeks postrehabilitation. Follow-up assessments were performed 1, 4, 12, and 24 weeks postrehabilitation. Safety was evaluated by monitoring adverse events (AEs) that occurred between enrollment and the end of rehabilitation.ResultsPrimary intent-to-treat analysis showed no group differences at 4 weeks, with PE being met by 32% and 29% of investigational and control patients, respectively (P = .36). Repeated-measures secondary analyses revealed no significant treatment group differences in mean UEFM or AMAT scores. However, post hoc comparisons showed that a greater proportion of investigational (39%) than control (15%) patients maintained or achieved PE (P = .003) at 24 weeks postrehabilitation. Investigational group mean AMAT scores also improved significantly (P < .05) when compared to the control group at 24 weeks postrehabilitation. Post hoc analyses also showed that 69% (n = 9/13) of the investigational patients who elicited movement thresholds during stimulation testing met PE at 4 weeks, and mean UEFM and AMAT scores was also significantly higher (P < .05) in this subgroup at the 4-, 12-, and 24-week assessments when compared to the control group. Headache (19%), pain (13%), swelling (7%), and infection (7%) were the most commonly observed implant procedure-related AEs. Overall, there were 11 serious AEs in 9 investigational group patients (7 procedure related, 4 anesthesia related).ConclusionsThe primary analysis pertaining to efficacy of EECS during upper limb motor rehabilitation in chronic stroke patients was negative at 4 weeks postrehabilitation. A better treatment response was observed in a subset of patients eliciting stimulation induced upper limb movements during motor threshold assessments performed prior to each rehabilitation session. Post hoc comparisons indicated treatment effect differences at 24 weeks, with the control group showing significant decline in the combined primary outcome measure relative to the investigational group. These results have the potential to inform future chronic stroke rehabilitation trial design
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