10,376 research outputs found
Production, reproduction, and reversion of protoplast-like structures in the osmotic strain of Neurospora crassa
Protoplasts devoid of cell walls have been produced in Bacillus megaterium and certain other Gram-positive species of bacteria.(1) Structures resembling protoplasts but not completely devoid of cell walls have also been produced in Escherichia coli and some other Gram-negative bacteria.(2) Those from Gram-positive and Gram-negative bacteria are alike in that they are spherical in shape and are lysed by osmotic shock. Bacterial protoplasts have already proved to have many useful applications among others, in the extraction of cellular constituents, in studies of the biosynthesis of enzymes and other macromolecular substances, and in host-parasite interrelations.(3
Scalable Noise Estimation with Random Unitary Operators
We describe a scalable stochastic method for the experimental measurement of
generalized fidelities characterizing the accuracy of the implementation of a
coherent quantum transformation. The method is based on the motion reversal of
random unitary operators. In the simplest case our method enables direct
estimation of the average gate fidelity. The more general fidelities are
characterized by a universal exponential rate of fidelity loss. In all cases
the measurable fidelity decrease is directly related to the strength of the
noise affecting the implementation -- quantified by the trace of the
superoperator describing the non--unitary dynamics. While the scalability of
our stochastic protocol makes it most relevant in large Hilbert spaces (when
quantum process tomography is infeasible), our method should be immediately
useful for evaluating the degree of control that is achievable in any prototype
quantum processing device. By varying over different experimental arrangements
and error-correction strategies additional information about the noise can be
determined.Comment: 8 pages; v2: published version (typos corrected; reference added
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Seeing the music in their hands: How conductors' depictions shape the music
Depiction is a way of ‘showing’ meaning through certain gestures or demonstrations. Conductors often use depiction, including multimodal depiction, as well as descriptive talk, to convey meaning to their choirs. This paper considers four short extracts from choir rehearsals with different conductors, to show how they combine description and depiction, including vocal models, facial expressions, metaphoric and iconic gestures and body language to communicate about music, specifically here as part of the activity of modelling
Randomized benchmarking of single and multi-qubit control in liquid-state NMR quantum information processing
Being able to quantify the level of coherent control in a proposed device
implementing a quantum information processor (QIP) is an important task for
both comparing different devices and assessing a device's prospects with
regards to achieving fault-tolerant quantum control. We implement in a
liquid-state nuclear magnetic resonance QIP the randomized benchmarking
protocol presented by Knill et al (PRA 77: 012307 (2008)). We report an error
per randomized pulse of with a
single qubit QIP and show an experimentally relevant error model where the
randomized benchmarking gives a signature fidelity decay which is not possible
to interpret as a single error per gate. We explore and experimentally
investigate multi-qubit extensions of this protocol and report an average error
rate for one and two qubit gates of for a three
qubit QIP. We estimate that these error rates are still not decoherence limited
and thus can be improved with modifications to the control hardware and
software.Comment: 10 pages, 6 figures, submitted versio
Genetic Interrelations of Two Andromonoecious Types of Maize, Dwarf and Anther Ear
Attention was called by Montgomery (1906)to the occasional appearance
of perfect flowers in the staminate inflorescence of maize and similar
cases were reported by Kempton (1913). Montgomery (1911) described
with illustrations a true-breeding type of semi-dwarf dent maize, the ears
of which were perfect-flowered. Perfect-flowered maize was described
and illustrated also by Blaringhem (1908, pp. 180-183). East and
Hayes (1911, pp. 13, 14) noted and illustrated a perfect-flowered sweet
corn. Weatherwax (1916, 1917) showed that typically pistillate
flowers of maize exhibit in microscopic sections the rudiments of stamens
and that staminate flowers show rudiments of pistils
Sinuosity and the affect grid: A method for adjusting repeated mood scores
Copyright @ 2012 Ammons Scientific. The article can be accessed from the links below.This article has been made available through the Brunel Open Access Publishing Fund.Sinuosity is a measure of how much a travelled pathway deviates from a straight line. In this paper, sinuosity is applied to the measurement of mood. The Affect Grid is a mood scale that requires participants to place a mark on a 9 x 9 grid to indicate their current mood. The grid has two dimensions: pleasure-displeasure (horizontal) and arousal-sleepiness (vertical). In studies where repeated measurements are required, some participants may exaggerate their mood shifts due to faulty interpretation of the scale or a feeling of social obligation to the experimenter. A new equation is proposed, based on the sinuosity measure in hydrology, a measure of the meandering of rivers. The equation takes into account an individual's presumed tendency to exaggerate and meander to correct the score and reduce outliers. The usefulness of the equation is demonstrated by applying it to Affect Grid data from another study.This article is made available through the Brunel Open Access Publishing Fund
The Inheritance of Sizes and Shapes in Plants
Some years ago Lock reported a cross of a tall race of maize with a shorter race which produced an intermediate height in F1 and exhibited no segregation in F2 when crossed back with one of the parents. Castle\u27s results with rabbits are very similar to those of Lock with maize. Castle summarizes his results in part as follows:
A cross between rabbits differing in ear-length produces offspring with ears of intermediate length, varying about the mean of the parental ear-lengths. . . . A study of the offspring of the primary cross-breds shows the blend of the parental characters to be permanent. No reappearance of the grand parental ear-lengths occurs in generation F2, nor are the individuals of that second generation as a rule more variable than those of the first generation of cross-breds.. . It seems probable that skeletal dimensions, and so proportions of skeletal parts, behave in general as blending characters. The linear dimensions of the skeletal parts of an individual approximate closely the mid-parental dimensions
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