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

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

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

Towards optimization-safe systems: analyzing the impact of undefined behavior

This paper studies an emerging class of software bugs called optimization-unstable code: code that is unexpectedly discarded by compiler optimizations due to undefined behavior in the program. Unstable code is present in many systems, including the Linux kernel and the Postgres database. The consequences of unstable code range from incorrect functionality to missing security checks. To reason about unstable code, this paper proposes a novel model, which views unstable code in terms of optimizations that leverage undefined behavior. Using this model, we introduce a new static checker called Stack that precisely identifies unstable code. Applying Stack to widely used systems has uncovered 160 new bugs that have been confirmed and fixed by developers.United States. Defense Advanced Research Projects Agency (DARPA Clean-slate design of Resilient, Adaptive, Secure Hosts (CRASH) program under contract #N66001-10-2-4089)National Science Foundation (U.S.) (NSF award CNS-1053143

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

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 ≥ 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 &lt; .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 &lt; .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

Testing the Standard Model and Schemes for Quark Mass Matrices with CP Asymmetries in B Decays

The values of $\sin (2 \alpha)$ and $\sin (2 \beta)$, where $\alpha$ and $\beta$ are angles of the unitarity triangle, will be readily measured in a B factory (and maybe also in hadron colliders). We study the standard model constraints in the $\sin (2 \alpha) - \sin (2 \beta)$ plane. We use the results from recent analyses of $f_B$ and $\tau_b|V_{cb}|^2$ which take into account heavy quark symmetry considerations. We find $\sin (2 \beta) \geq 0.15$ and most likely \sin (2 \beta) \roughly{>} 0.6, and emphasize the strong correlations between $\sin (2 \alpha)$ and $\sin (2 \beta)$. Various schemes for quark mass matrices allow much smaller areas in the $\sin (2 \alpha) - \sin (2 \beta)$ plane. We study the schemes of Fritzsch, of Dimopoulos, Hall and Raby, and of Giudice, as well as the ``symmetric CKM'' idea, and show how CP asymmetries in B decays will crucially test each of these schemes.Comment: 11 pages and 4 postscript figures available on request, LaTeX, WIS-92/52/Jun-PH, LBL-3256

Glimpse: Continuous, Real-Time Object Recognition on Mobile Devices

Glimpse is a continuous, real-time object recognition system for camera-equipped mobile devices. Glimpse captures full-motion video, locates objects of interest, recognizes and labels them, and tracks them from frame to frame for the user. Because the algorithms for object recognition entail significant computation, Glimpse runs them on server machines. When the latency between the server and mobile device is higher than a frame-time, this approach lowers object recognition accuracy. To regain accuracy, Glimpse uses an active cache of video frames on the mobile device. A subset of the frames in the active cache are used to track objects on the mobile, using (stale) hints about objects that arrive from the server from time to time. To reduce network bandwidth usage, Glimpse computes trigger frames to send to the server for recognizing and labeling. Experiments with Android smartphones and Google Glass over Verizon, AT&T, and a campus Wi-Fi network show that with hardware face detection support (available on many mobile devices), Glimpse achieves precision between 96.4% to 99.8% for continuous face recognition, which improves over a scheme performing hardware face detection and server-side recognition without Glimpse's techniques by between 1.8-2.5×. The improvement in precision for face recognition without hardware detection is between 1.6-5.5×. For road sign recognition, which does not have a hardware detector, Glimpse achieves precision between 75% and 80%; without Glimpse, continuous detection is non-functional (0.2%-1.9% precision)

Strong rescattering in K-> 3pi decays and low-energy meson dynamics

We present a consistent analysis of final state interactions in ${K\rightarrow 3\pi}$ 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 $K_S-K_L$ interference experiments is also analyzed.Comment: 14 pages in RevTex, 3 figures in postscrip

Repetitive arm functional tasks after stroke (RAFTAS): a pilot randomised controlled trial

Background Repetitive functional task practise (RFTP) is a promising treatment to improve upper limb recovery following stroke. We report the findings of a study to determine the feasibility of a multi-centre randomised controlled trial to evaluate this intervention. Methods A pilot randomised controlled trial was conducted. Patients with new reduced upper limb function were recruited within 14 days of acute stroke from three stroke units in North East England. Participants were randomised to receive a four week upper limb RFTP therapy programme consisting of goal setting, independent activity practise, and twice weekly therapy reviews in addition to usual post stroke rehabilitation, or usual post stroke rehabilitation. The recruitment rate; adherence to the RFTP therapy programme; usual post stroke rehabilitation received; attrition rate; data quality; success of outcome assessor blinding; adverse events; and the views of study participants and therapists about the intervention were recorded. Results Fifty five eligible patients were identified, 4-6% of patients screened at each site. Twenty four patients participated in the pilot study. Two of the three study sites met the recruitment target of 1-2 participants per month. The median number of face to face therapy sessions received was 6 [IQR 3-8]. The median number of daily repetitions of activities recorded was 80 [IQR 39-80]. Data about usual post stroke rehabilitation were available for 18/24 (75%). Outcome data were available for 22/24 (92%) at one month and 20/24 (83%) at three months. Outcome assessors were unblinded to participant group allocation for 11/22 (50%) at one month and 6/20 (30%) at three months. Four adverse events were considered serious as they resulted in hospitalisation. None were related to study treatment. Feedback from patients and local NHS therapists about the RFTP programme was mainly positive. Conclusions A multi-centre randomised controlled trial to evaluate an upper limb RFTP therapy programme provided early after stroke is feasible and acceptable to patients and therapists, but there are issues which needed to be addressed when designing a Phase III study. A Phase III study will need to monitor and report not only recruitment and attrition but also adherence to the intervention, usual post stroke rehabilitation received, and outcome assessor blinding