6,316 research outputs found
Understanding Current Signals Induced by Drifting Electrons
Consider an electron drifting in a gas toward a collection electrode. A
common misconception is that the electron produces a detectable signal only
upon arrival at the electrode. In fact, the situation is quite the opposite.
The electron induces a detectable current in the electrode as soon as it starts
moving through the gas. This induced current vanishes when the electron arrives
at the plate. To illustrate this phenomenon experimentally, we use a gas-filled
parallel plate ionization chamber and a collimated Am alpha source,
which produces a track of a fixed number of ionization electrons at a constant
distance from the collection electrode. We find that the detected signal from
the ionization chamber grows with the electron drift distance, as predicted by
the model of charge induction, and in conflict with the idea that electrons are
detectable upon arrival at the collection plate.Comment: 21 pages, 12 figure
Tripartite Entanglement Extraction from the Black Hole Vacuum
The first investigation of tripartite entanglement harvesting in the vicinity
of a black hole is carried out. Working in the context of a static
Ba\~{n}ados-Teitelboim-Zanelli (BTZ) black hole spacetime we find that it is
possible to harvest tripartite entanglement in regions where harvesting of
bipartite entanglement is known to be impossible due to intense Hawking
radiation. In these situations, it implies that the harvested entanglement is
of the Greenberger-Horne-Zeilinger (GHZ) type.Comment: 12 pages, 8 figures; (v2) matched to the final versio
Whole-genome assembly of the coral reef Pearlscale Pygmy Angelfish (Centropyge vrolikii)
The diversity of DNA sequencing methods and algorithms for genome assemblies presents scientists with a bewildering array of choices. Here, we construct and compare eight candidate assemblies combining overlapping shotgun read data, mate-pair and Chicago libraries and four different genome assemblers to produce a high-quality draft genome of the iconic coral reef Pearlscale Pygmy Angelfish, Centropyge vrolikii (family Pomacanthidae). The best candidate assembly combined all four data types and had a scaffold N50 127.5 times higher than the candidate assembly obtained from shotgun data only. Our best candidate assembly had a scaffold N50 of 8.97 Mb, contig N50 of 189,827, and 97.4% complete for BUSCO v2 (Actinopterygii set) and 95.6% complete for CEGMA matches. These contiguity and accuracy scores are higher than those of any other fish assembly released to date that did not apply linkage map information, including those based on more expensive long-read sequencing data. Our analysis of how different data types improve assembly quality will help others choose the most appropriate de novo genome sequencing strategy based on resources and target applications. Furthermore, the draft genome of the Pearlscale Pygmy angelfish will play an important role in future studies of coral reef fish evolution, diversity and conservationUC Berkeley | Ref. S10RR029668UC Berkeley | Ref. S10RR02730
Dynamics of correlations due to a phase noisy laser
We analyze the dynamics of various kinds of correlations present between two
initially entangled independent qubits, each one subject to a local phase noisy
laser. We give explicit expressions of the relevant quantifiers of correlations
for the general case of single-qubit unital evolution, which includes the case
of a phase noisy laser. Although the light field is treated as classical, we
find that this model can describe revivals of quantum correlations. Two
different dynamical regimes of decay of correlations occur, a Markovian one
(exponential decay) and a non-Markovian one (oscillatory decay with revivals)
depending on the values of system parameters. In particular, in the
non-Markovian regime, quantum correlations quantified by quantum discord show
an oscillatory decay faster than that of classical correlations. Moreover,
there are time regions where nonzero discord is present while entanglement is
zero.Comment: 7 pages, 3 figures, accepted for publication in Phys. Scripta,
special issue for CEWQO 2011 proceeding
Chronicles of Oklahoma
Article details the experiences of James C. Henderson as a range rider during the establishment of Kay County and the Cherokee strip within Oklahoma. He wrote his manuscript documenting his life for his two young sons. Included in the article are experts from the manuscript
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Mitigating the Impacts of Uncontrolled Air Flow on Indoor Environmental Quality and Energy Demand in Non-Residential Buildings
This multi-faceted study evaluated several aspects of uncontrolled air flows in commercial buildings in both Northern and Southern climates. Field data were collected from 25 small commercial buildings in New York State to understand baseline conditions for Northern buildings. Laboratory wall assembly testing was completed at Syracuse University to understand the impact of typical air leakage pathways on heat and moisture transport within wall assemblies for both Northern and Southern building applications. The experimental data from the laboratory tests were used to verify detailed heat and moisture (HAM) simulation models that could be used to evaluate a wider array of building applications and situations. Whole building testing at FSEC's Building Science Laboratory (BSL) systematically evaluated the energy and IAQ impacts of duct leakage with various attic and ceiling configurations. This systematic test carefully controlled all aspects of building performance to quantify the impact of duct leakage and unbalanced flow. The newest features of the EnergyPlus building simulation tool were used to model the combined impacts of duct leakage, ceiling leakage, unbalanced flows, and air conditioner performance. The experimental data provided the basis to validate the simulation model so it could be used to study the impact of duct leakage over a wide range of climates and applications. The overall objective of this project was to transfer work and knowledge that has been done on uncontrolled air flow in non-residential buildings in Florida to a national basis. This objective was implemented by means of four tasks: (1) Field testing and monitoring of uncontrolled air flow in a sample of New York buildings; (2) Detailed wall assembly laboratory measurements and modeling; (3) Whole building experiments and simulation of uncontrolled air flows; and (4) Develop and implement training on uncontrolled air flows for Practitioners in New York State
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