323 research outputs found
Massively parallel quantum computer simulator, eleven years later
A revised version of the massively parallel simulator of a universal quantum
computer, described in this journal eleven years ago, is used to benchmark
various gate-based quantum algorithms on some of the most powerful
supercomputers that exist today. Adaptive encoding of the wave function reduces
the memory requirement by a factor of eight, making it possible to simulate
universal quantum computers with up to 48 qubits on the Sunway TaihuLight and
on the K computer. The simulator exhibits close-to-ideal weak-scaling behavior
on the Sunway TaihuLight,on the K computer, on an IBM Blue Gene/Q, and on Intel
Xeon based clusters, implying that the combination of parallelization and
hardware can track the exponential scaling due to the increasing number of
qubits. Results of executing simple quantum circuits and Shor's factorization
algorithm on quantum computers containing up to 48 qubits are presented.Comment: Substantially rewritten + new data. Published in Computer Physics
Communicatio
Lateral female strobili production in a Japanese red pine (Pinus densiflora Sieb. et Zucc.) clone by exogenous cytokinin application
Application of N6-benzylaminopurine(BAP) and gibberellin(GA3) to a grafted Japanese red pine(Pinus densiflora Sieb. et Zucc.) clone promoted flowering. BAP(250mg/l) was sprayed five times to the top of branches in July or September 1992. GA3(100 or 500mg/l) was applied five times to the whole plants by spray treatment during the above period, or GA3 solution of the same concentration was injected once into a small incision made in the main stem of clone trees at the beginning of July or the middle of September 1992. In May 1993, no apical female strobili were observed at the top of the new shoots in any treatment. However, lateral female and bisexual strobili were produced in the lower part of new shoots by BAP application in September, regardless of GA3 application. BAP applied in September without GA3 application was sufficient to produce lateral female and bisexual strobili. In such treatment, production of female and bisexual strobili was 47 and 25, and they occurred in 16 out of 68 new shoots, 11 out of 15 treated branches and 5 out of 5 treated trees. The average number of female and bisexual strobili per new shoot was 1.06. BAP treatment either in July or in September significantly decreased (p<0.005) the production of male strobili. These results indicate that BAP application induces the development of lateral female strobili in Japanese red pine when applied during the period of floral differentiation
Development of an optimal laser for chirp cooling of positronium based on chirped pulse-train generator
We report the development and characterization of a pulsed 243 nm laser that
is optimal for the cooling of positronium (Ps). The laser, which is based on
the recent chirped pulse-train generator (CPTG) demonstrated by K. Yamada et
al. (Phys. Rev. Appl. 16, 014009 (2021)), was designed to output a train of
pulses with linewidths of 10 GHz, and with the center frequency of each pulse
shifting upward (up-chirped) in time by . These parameters were determined by the mechanism of chirp cooling,
which is the best scheme for cooling many Ps atoms to the recoil temperature of
laser cooling. To achieve the designed performance, we drove an optical phase
modulator in the CPTG with a deep modulation depth based on the operating
principle of the cooling laser. Time-resolved spectroscopic measurements
confirmed that the developed laser satisfied the chirp rate and linewidth
requirements for efficient chirp cooling. Combined with pulse energy of
hundreds of microjoules, we believe that the experimental demonstration of Ps
laser cooling has become possible using realistic methods for the generation
and velocity measurement of Ps.Comment: 11 pages, 11 figure
Central venous pulse pressure analysis using an R-synchronized pressure measurement system
Objective. The information derived from central venous catheters is underused. We developed an EKG-R synchronization and averaging system to obtained distinct CVP waveforms and analyzed components of these.
Methods. Twenty-five paralyzed surgical patients undergoing CVP monitoring under mechanical ventilation were studied. CVP and EKG signals were analyzed employing our system, the mean CVP and CVP at end-diastole during expiration were compared, and CVP waveform components were measured using this system.
Results. CVP waveforms were clearly visualized in all patients. They showed the a peak to be 1.8+/- 0.7 mmHg, which was the highest of three peaks, and the x trough to be lower than the y trough (-1.6+/- 0.7mmHgand-0.9+/- 0.5mmHg, respectively), with a mean pulse pressure of 3.4mm Hg.The difference between the mean CVP and CVP at end-diastole during expiration was 0.58+/- 0.81 mmHg.
Conclusions. The mean CVP can be used as an index of right ventricular preload in patients under mechanical ventilation with regular sinus rhythm. Our newly developed system is useful for clinical monitoring and for education in circulatory physiology
Simultaneous recovery of high-purity copper and polyvinyl chloride from thin electric cables by plasticizer extraction and ball milling
Herein, we introduce a combination of plasticizer extraction from polyvinyl chloride (PVC) and ball milling for the simultaneous, effective recovery of PVC and copper (Cu) from thin electric cables. PVC coverings typically contain plasticizers for flexibility. As such, PVC cables become brittle after plasticizer extraction, causing them to be easily crushed by physical impact. Hence, we extracted the plasticizers from the PVC coverings of electric cables using organic solvents, and then crushed the obtained cable samples by ball milling. The influences of the plasticizer extraction yield and PVC morphologies before and after extraction on separation by ball milling were investigated. After a series of treatments to PVC coverings including quantitatively de-plasticizing for 5 h by Soxhlet-extraction in diethyl ether, 6 h ball milling and 1 h shaking in the sieve shaker, a maximum separation rate of 77% was achieved and the purity of the obtained separated Cu reached >99.8%
Slc12a8 in the lateral hypothalamus maintains energy metabolism and skeletal muscle functions during aging
Sarcopenia and frailty are urgent socio-economic problems worldwide. Here we demonstrate a functional connection between the lateral hypothalamus (LH) and skeletal muscle through Slc12a8, a recently identified nicotinamide mononucleotide transporter, and its relationship to sarcopenia and frailty. Slc12a8-expressing cells are mainly localized in the LH. LH-specific knockdown of Slc12a8 in young mice decreases activity-dependent energy and carbohydrate expenditure and skeletal muscle functions, including muscle mass, muscle force, intramuscular glycolysis, and protein synthesis. LH-specific Slc12a8 knockdown also decreases sympathetic nerve signals at neuromuscular junctions and β2-adrenergic receptors in skeletal muscle, indicating the importance of the LH-sympathetic nerve-β2-adrenergic receptor axis. LH-specific overexpression of Slc12a8 in aged mice significantly ameliorates age-associated decreases in energy expenditure and skeletal muscle functions. Our results highlight an important role of Slc12a8 in the LH for regulation of whole-body metabolism and skeletal muscle functions and provide insights into the pathogenesis of sarcopenia and frailty during aging
Canary in Twitter Mine: Collecting Phishing Reports from Experts and Non-experts
The rise in phishing attacks via e-mail and short message service (SMS) has
not slowed down at all. The first thing we need to do to combat the
ever-increasing number of phishing attacks is to collect and characterize more
phishing cases that reach end users. Without understanding these
characteristics, anti-phishing countermeasures cannot evolve. In this study, we
propose an approach using Twitter as a new observation point to immediately
collect and characterize phishing cases via e-mail and SMS that evade
countermeasures and reach users. Specifically, we propose CrowdCanary, a system
capable of structurally and accurately extracting phishing information (e.g.,
URLs and domains) from tweets about phishing by users who have actually
discovered or encountered it. In our three months of live operation,
CrowdCanary identified 35,432 phishing URLs out of 38,935 phishing reports. We
confirmed that 31,960 (90.2%) of these phishing URLs were later detected by the
anti-virus engine, demonstrating that CrowdCanary is superior to existing
systems in both accuracy and volume of threat extraction. We also analyzed
users who shared phishing threats by utilizing the extracted phishing URLs and
categorized them into two distinct groups - namely, experts and non-experts. As
a result, we found that CrowdCanary could collect information that is
specifically included in non-expert reports, such as information shared only by
the company brand name in the tweet, information about phishing attacks that we
find only in the image of the tweet, and information about the landing page
before the redirect
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