High-Q/V air-mode photonic crystal cavities at microwave frequencies

We present results for a photonic microwave resonator designed and fabricated at 17.4GHz with a record high Quality factor (Q = 26,400) at room temperature over a mode volume smaller than one cubic wavelength. The cavity is uniquely designed to have its electric field concentrated in air, which allows for efficient coupling to free space and facilitates interactions with gaseous atomic systems and fluids.Comment: 10 pages, 4 figure

Electron elastic scattering off a Tensor-polarized Deuterium Internal Target

The tensor analyzing power Γ20 in elastic electron-deuteron scattering has been measured in the four momentum transfer region between 1.4 and 3.2 fm~l using the Internal Target Facility at NIKHEF. Tensor-polarized deuterium is produced in an Atomic Beam Source and injected into a storage cell. Scattered electrons and recoil deuterons were detected in coincidence with two large acceptance nonmagnetic detectors

Muon Radiography as a Novel Tool to Characterize Tailing Storage Facilities

We report on the potential of the muon density radiography technique for the in-situ characterization and digital mapping of the distribution of unit weights within tailingsstorage facilities (TSF). Muon radiography or muography is a well-established technique for measuring the bulk density of dense objects across large scales. As with other more conventional nuclear inspection methods, muography is robust, direct, and quantitative. However, in place of the radio-nuclide sources or X-ray tubes used in conventional medical or industrial X-ray applications, muon radiography utilizes the naturally occurring flux of so-called secondary cosmic ray particles (aka muons) originating in the earth’s atmosphere. This background radiation source is not only free and intrinsically safe, but also well-characterized and continuously available everywhere on earth. Muon particles are also highly penetrating and maintain excellent directionality even in the subsurface. This allows muographers to analyze and map the interior of large, dense structures and provide in-situ volumetric density data in a minimally invasive way without the disadvantages of using a dangerous nuclear logging source. In this paper we will show results from high fidelity, fully 3D, nuclear transport calculations to simulate the response and sensitivity of muon radiography sensors placed at different locations, including pre-existing slim boreholes, within an upstream tailings dam. We will compare typical trade-offs between measurement precision, spatial resolution, and measurement time, as a function of different installation set ups, and focus on the practical and urgent issue of quantifying groundwater content and characterizing the location of phreatic surfaces over a dense 3D data grid within a tailings dam. We believe that muography can provide a unique and powerful tool for geophysical characterization of actively managing geotechnical risk in tailing storage facilities, provided that practical installation choices in either existing or ad-hoc boreholes can be made.Non UBCUnreviewedOthe

Measurement of the Vector and Tensor Asymmetries at Large Missing Momentum in Quasielastic ([→ over e],e′p) Electron Scattering from Deuterium

We report the measurement of the beam-vector and tensor asymmetries A[subscript ed][superscript V] and A[subscript d][superscript T] in quasielastic ([→ over e],e′p) electrodisintegration of the deuteron at the MIT-Bates Linear Accelerator Center up to missing momentum of 500  MeV/c. Data were collected simultaneously over a momentum transfer range 0.1<Q[superscript 2]<0.5  (GeV/c)[superscript 2] with the Bates Large Acceptance Spectrometer Toroid using an internal deuterium gas target polarized sequentially in both vector and tensor states. The data are compared with calculations. The beam-vector asymmetry A[subscript ed][superscript V] is found to be directly sensitive to the D-wave component of the deuteron and has a zero crossing at a missing momentum of about 320  MeV/c, as predicted. The tensor asymmetry A[subscript d][superscript T] at large missing momentum is found to be dominated by the influence of the tensor force in the neutron-proton final-state interaction. The new data provide a strong constraint on theoretical models

Endovascular treatment for acute ischemic stroke

BACKGROUND: In patients with ischemic stroke, endovascular treatment results in a higher rate of recanalization of the affected cerebral artery than systemic intravenous thrombolytic therapy. However, comparison of the clinical efficacy of the two approaches is needed. METHODS: We randomly assigned 362 patients with acute ischemic stroke, within 4.5 hours after onset, to endovascular therapy (intraarterial thrombolysis with recombinant tissue plasminogen activator [t-PA], mechanical clot disruption or retrieval, or a combination of these approaches) or intravenous t-PA. Treatments were to be given as soon as possible after randomization. The primary outcome was survival free of disability (defined as a modified Rankin score of 0 or 1 on a scale of 0 to 6, with 0 indicating no symptoms, 1 no clinically significant disability despite symptoms, and 6 death) at 3 months. RESULTS: A total of 181 patients were assigned to receive endovascular therapy, and 181 intravenous t-PA. The median time from stroke onset to the start of treatment was 3.75 hours for endovascular therapy and 2.75 hours for intravenous t-PA (P<0.001). At 3 months, 55 patients in the endovascular-therapy group (30.4%) and 63 in the intravenous t-PA group (34.8%) were alive without disability (odds ratio adjusted for age, sex, stroke severity, and atrial fibrillation status at baseline, 0.71; 95% confidence interval, 0.44 to 1.14; P=0.16). Fatal or nonfatal symptomatic intracranial hemorrhage within 7 days occurred in 6% of the patients in each group, and there were no significant differences between groups in the rates of other serious adverse events or the case fatality rate. CONCLUSIONS: The results of this trial in patients with acute ischemic stroke indicate that endovascular therapy is not superior to standard treatment with intravenous t-PA. (Funded by the Italian Medicines Agency, ClinicalTrials.gov number, NCT00640367.)