38,200 research outputs found
Scalable quantum computation with fast gates in two-dimensional microtrap arrays of trapped ions
We theoretically investigate the use of fast pulsed two-qubit gates for
trapped ion quantum computing in a two-dimensional microtrap architecture. In
one dimension, such fast gates are optimal when employed between nearest
neighbours, and we examine the generalisation to a two-dimensional geometry. We
demonstrate that fast pulsed gates are capable of implementing high-fidelity
entangling operations between ions in neighbouring traps faster than the
trapping period, with experimentally demonstrated laser repetition rates.
Notably, we find that without increasing the gate duration, high-fidelity gates
are achievable even in large arrays with hundreds of ions. To demonstrate the
usefulness of this proposal, we investigate the application of these gates to
the digital simulation of a 40-mode Fermi-Hubbard model. This also demonstrates
why shorter chains of gates required to connect arbitrary pairs of ions makes
this geometry well suited for large-scale computation
Point of Care Diagnosis of Multiple Schistosome Parasites: Species-specific DNA Detection in Urine by Loop-mediated Isothermal Amplification (LAMP)
Schistosomes are easily transmitted and high chance of repeat infection, so if control strategies based on targeted mass drug administration (MDA) are to succeed it is essential to have a test that is sensitive, accurate and simple to use. It is known and regularly demonstrated that praziquantel does not always eliminate an infection so in spite of the successes of control programs a residual of the reservoir survives to re-infect snails. The issue of diagnostic sensitivity becomes more critical in the assessment of program effectiveness. While serology, such as antigen capture tests might improve sensitivity, it has been shown that the presence of species-specific DNA fragments will indicate, most effectively, the presence of active parasites. Polymerase chain reaction (PCR) can amplify and detect DNA from urine residue captured on Whatman No. 3 filter paper that is dried after filtration. Previously we have detected S. mansoni and S. haematobium parasite-specific small repeat DNA fragment from filtered urine on filter paper by PCR. In the current study, we assessed the efficacy of detection of 86 urine samples for either or both schistosome parasites by PCR and loop-mediated isothermal amplification (LAMP) that were collected from a low to moderate transmission area in Ghana. Two different DNA extraction methods, standard extraction kit and field usable LAMP-PURE kit were also evaluated by PCR and LAMP amplification. With S. haematobium LAMP amplification for both extractions showed similar sensitivity and specificity when compared with PCR amplification (100%) verified by gel electrophoresis. For S. mansoni sensitivity was highest for LAMP amplification (100%) for standard extraction than PCR and LAMP with LAMP-PURE (99% and 94%). The LAMP-PURE extraction produced false negatives, which require further investigation for this field usable extraction kit. Overall high positive and negative predictive values (90% − 100%) for both species demonstrated a highly robust approach. The LAMP approach is close to point of care use and equally sensitive and specific to detection of species-specific DNA by PCR. LAMP can be an effective means to detect low intensity infection due to its simplicity and minimal DNA extraction requirement. This will enhance the effectiveness of surveillance and MDA control programs of schistosomiasis
C4Synth: Cross-Caption Cycle-Consistent Text-to-Image Synthesis
Generating an image from its description is a challenging task worth solving
because of its numerous practical applications ranging from image editing to
virtual reality. All existing methods use one single caption to generate a
plausible image. A single caption by itself, can be limited, and may not be
able to capture the variety of concepts and behavior that may be present in the
image. We propose two deep generative models that generate an image by making
use of multiple captions describing it. This is achieved by ensuring
'Cross-Caption Cycle Consistency' between the multiple captions and the
generated image(s). We report quantitative and qualitative results on the
standard Caltech-UCSD Birds (CUB) and Oxford-102 Flowers datasets to validate
the efficacy of the proposed approach.Comment: To appear in the proceedings of IEEE Winter Conference on
Applications of Computer Vision, WACV-201
Measurement of the threshold sensitivity of honeybees to weak, extremely low-frequency magnetic fields
Experiments reported previously demonstrate that free-flying honeybees are able to detect static intensity fluctuations as weak as 26 nT against the background, earth-strength magnetic field. We report here an extension of this work to weak, alternating fields at frequencies of 10 and 60 Hz. Our results indicate that the sensitivity of the honeybee magnetoreception system decreases rapidly with increasing frequency. At 60 Hz, alternating field strengths above 100 µT are required to elicit discrimination. These results are consistent with biophysical predictions of a magnetite-based magnetoreceptor
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An Evaluation of the Mechanical Behavior of Bronze-NI Composites Produced by Selective Laser Sintering
Mechanical properties of Bronze-Nickel composites produced by Selective Laser Sintering (SLS)
were evaluated by constant displacement tension tests. These were studied as a function of SLS
process parameters - laser power density, scan speed, scan spacing, scan direction and layer
thickness. The strength data was then correlated to the microstructure and the part bulk density. To
further enhance the part densities and the mechanical properties, post-SLS sintering was studied.
The relationships between SLS process parameters, post-SLS sintering parameters and the
resulting microstructures, part bulk density and the mechanical properties will be described.Mechanical Engineerin
Interference Drag Associated with Engine Locations for Multidisciplinary Design Optimization
This research aims to quantify the interference drag for various engine locations on a traditional tube and wing, 150-passenger commercial aircraft flying at 35,000 ft and Mach 0.8. Engine locations are varied in the chord wise, span wise, and vertical directions near the wing, both under and above the wing, as well as along the fuselage. Euler simulations are performed with representative powered modern engines. The results are intended to supplement empirical drag estimates suitable for multidisciplinary design environments. Large interference drag increases, as compared to the isolated air frame and engine geometry, are found to occur when the engine is placed directly above or below the wing. Interference effects are significantly reduced, and in some instances result in benefits compared to the isolated bodies, when the engines are placed fore or aft of the wing. Interference drag increases are partially explained by flow channels leading to choked flow and shock interactions between bodies
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