237 research outputs found
An addressable quantum dot qubit with fault-tolerant control fidelity
Exciting progress towards spin-based quantum computing has recently been made
with qubits realized using nitrogen-vacancy (N-V) centers in diamond and
phosphorus atoms in silicon, including the demonstration of long coherence
times made possible by the presence of spin-free isotopes of carbon and
silicon. However, despite promising single-atom nanotechnologies, there remain
substantial challenges in coupling such qubits and addressing them
individually. Conversely, lithographically defined quantum dots have an
exchange coupling that can be precisely engineered, but strong coupling to
noise has severely limited their dephasing times and control fidelities. Here
we combine the best aspects of both spin qubit schemes and demonstrate a
gate-addressable quantum dot qubit in isotopically engineered silicon with a
control fidelity of 99.6%, obtained via Clifford based randomized benchmarking
and consistent with that required for fault-tolerant quantum computing. This
qubit has orders of magnitude improved coherence times compared with other
quantum dot qubits, with T_2* = 120 mus and T_2 = 28 ms. By gate-voltage tuning
of the electron g*-factor, we can Stark shift the electron spin resonance (ESR)
frequency by more than 3000 times the 2.4 kHz ESR linewidth, providing a direct
path to large-scale arrays of addressable high-fidelity qubits that are
compatible with existing manufacturing technologies
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First measurement of neutrino oscillation parameters using neutrinos and antineutrinos by NOvA.
The NOvA experiment has seen a 4.4Ï signal of Îœ[over ÂŻ]_{e} appearance in a 2 GeV Îœ[over ÂŻ]_{ÎŒ} beam at a distance of 810 km. Using 12.33Ă10^{20} protons on target delivered to the Fermilab NuMI neutrino beamline, the experiment recorded 27 Îœ[over ÂŻ]_{ÎŒ}âÎœ[over ÂŻ]_{e} candidates with a background of 10.3 and 102 Îœ[over ÂŻ]_{ÎŒ}âÎœ[over ÂŻ]_{ÎŒ} candidates. This new antineutrino data are combined with neutrino data to measure the parameters |Îm_{32}^{2}|=2.48_{-0.06}^{+0.11}Ă10^{-3}ââeV^{2}/c^{4} and sin^{2}Ξ_{23} in the ranges from (0.53-0.60) and (0.45-0.48) in the normal neutrino mass hierarchy. The data exclude most values near ÎŽ_{CP}=Ï/2 for the inverted mass hierarchy by more than 3Ï and favor the normal neutrino mass hierarchy by 1.9Ï and Ξ_{23} values in the upper octant by 1.6Ï
Clinical Characteristics of Patients Responding to Once-Daily Basal Insulin Therapy in Korean Subjects with Type 2 Diabetes
Advanced Trauma Life SupportÂź. ABCDE from a radiological point of view
Accidents are the primary cause of death in patients aged 45Â years or younger. In many countries, Advanced Trauma Life SupportÂź (ATLSÂź) is the foundation on which trauma care is based. We will summarize the principles and the radiological aspects of the ATLSÂź, and we will discuss discrepancies with day to day practice and the radiological literature. Because the ATLSÂź is neither thorough nor up-to-date concerning several parts of radiology in trauma, it should not be adopted without serious attention to defining the indications and limitations pertaining to diagnostic imaging
Radiation Exposure from CT Examinations in Japan
<p>Abstract</p> <p>Background</p> <p>Computed tomography (CT) is the largest source of medical radiation exposure to the general population, and is considered a potential source of increased cancer risk. The aim of this study was to assess the current situation of CT use in Japan, and to investigate variations in radiation exposure in CT studies among institutions and scanners.</p> <p>Methods</p> <p>Data-sheets were sent to all 126 hospitals and randomly selected 14 (15%) of 94 clinics in Gunma prefecture which had CT scanner(s). Data for patients undergoing CT during a single month (June 2008) were obtained, along with CT scan protocols for each institution surveyed. Age and sex specific patterns of CT examination, the variation in radiation exposure from CT examinations, and factors which were responsible for the variation in radiation exposure were determined.</p> <p>Results</p> <p>An estimated 235.4 patients per 1,000 population undergo CT examinations each year, and 50% of the patients were scanned in two or more anatomical locations in one CT session. There was a large variation in effective dose among hospitals surveyed, particularly in lower abdominal CT (range, 2.6-19.0 mSv). CT examinations of the chest and upper abdomen contributed to approximately 73.2% of the collective dose from all CT examinations. It was estimated that in Japan, approximately 29.9 million patients undergo CT annually, and the estimated annual collective effective dose in Japan was 277.4 *10<sup>3 </sup>Sv person. The annual effective dose per capita for Japan was estimated to be 2.20 mSv.</p> <p>Conclusions</p> <p>There was a very large variation in radiation exposure from CT among institutions surveyed. CT examinations of the chest and upper abdomen were the predominant contributors to the collective dose.</p
Brief gatekeeper training for suicide prevention in an ethnic minority population: a controlled intervention
Relationship of family caregiver burden with quality of care and psychopathology in a sample of Arab subjects with schizophrenia
Correlation between preoperative predictions and surgical findings in the parotid surgery for tumors
Quando a fase de equilĂbrio pode ser suprimida nos exames de tomografia computadorizada de abdome?
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