2,327 research outputs found
Coherent rotations of a single spin-based qubit in a single quantum dot at fixed Zeeman energy
Coherent rotations of single spin-based qubits may be accomplished
electrically at fixed Zeeman energy with a qubit defined solely within a single
electrostatically-defined quantum dot; the -factor and the external magnetic
field are kept constant. All that is required to be varied are the voltages on
metallic gates which effectively change the shape of the elliptic quantum dot.
The pseudospin-1/2 qubit is constructed from the two-dimensional ,
subspace of three interacting electrons in a two-dimensional
potential well. Rotations are created by altering the direction of the
pseudomagnetic field through changes in the shape of the confinement potential.
By deriving an exact analytic solution to the long-range Coulomb interaction
matrix elements, we calculate explicitly the range of magnitudes and directions
the pseudomagnetic field can take. Numerical estimates are given for {GaAs}.Comment: Restructured manuscript, more details shown (results unchanged); Six
pages, revtex4; More info at http://soliton.phys.dal.c
Targeting Mr Average: Participation, gender equity and school sport partnerships
The School Sport Partnership Programme (SSPP) is one strand of the national strategy for physical education and school sport in England, the physical education and school sport Club Links Strategy (PESSCL). The SSPP aims to make links between school physical education (PE) and out of school sports participation, and has a particular remit to raise the participation levels of several identified under-represented groups, of which girls and young women are one. National evaluations of the SSPP show that it is beginning to have positive impacts on young people's activity levels by increasing the range and provision of extra curricular activities (Office for Standards in Education (OFSTED), 2003, 2004, 2005; Loughborough Partnership, 2005, 2006). This paper contributes to the developing picture of the phased implementation of the programme by providing qualitative insights into the work of one school sport partnership with a particular focus on gender equity. The paper explores the ways in which gender equity issues have been explicitly addressed within the 'official texts' of the SSPP; how these have shifted over time and how teachers are responding to and making sense of these in their daily practice. Using participation observation, interview and questionnaire data, the paper explores how the coordinators are addressing the challenge of increasing the participation of girls and young women. The paper draws on Walby's (2000) conceptualisation of different kinds of feminist praxis to highlight the limitations of the coordinators' work. Two key themes from the data and their implications are addressed: the dominance of competitive sport practices and the PE professionals' views of targeting as a strategy for increasing the participation of under-represented groups. The paper concludes that coordinators work within an equality or difference discourse with little evidence of the transformative praxis needed for the programme to be truly inclusive. © 2008 Taylor & Francis
Letter from J.C. Penney, 1933
Famed business leader J.C. Penney sent a letter to Governor William Langer on September 11, 1933, thanking Langer for the return of brochures about chain store tax.
James Cash Penney founded the J.C. Penney stores in 1902.https://commons.und.edu/langer-papers/1051/thumbnail.jp
Finite difference time domain modeling of spiral antennas
The objectives outlined in the original proposal for this project were to create a well-documented computer analysis model based on the finite-difference, time-domain (FDTD) method that would be capable of computing antenna impedance, far-zone radiation patterns, and radar cross-section (RCS). The ability to model a variety of penetrable materials in addition to conductors is also desired. The spiral antennas under study by this project meet these requirements since they are constructed of slots cut into conducting surfaces which are backed by dielectric materials
Frogeye Leaf Spot Resistance in Soybean
Isolates of Cercospora sojina showing reduced sensitivity to quinone outside inhibitor (QoI, strobilurin) fungicides were recently recovered from soybean in Iowa. This pathogen causes frogeye leaf spot, an important foliar soybean disease that can be managed with fungicides. With the confirmation of fungicide-resistant isolates, it becomes especially important to understand when to spray and what products to use for long-term control of this disease
A recurrent neural network with ever changing synapses
A recurrent neural network with noisy input is studied analytically, on the
basis of a Discrete Time Master Equation. The latter is derived from a
biologically realizable learning rule for the weights of the connections. In a
numerical study it is found that the fixed points of the dynamics of the net
are time dependent, implying that the representation in the brain of a fixed
piece of information (e.g., a word to be recognized) is not fixed in time.Comment: 17 pages, LaTeX, 4 figure
Hierarchical Self-Programming in Recurrent Neural Networks
We study self-programming in recurrent neural networks where both neurons
(the `processors') and synaptic interactions (`the programme') evolve in time
simultaneously, according to specific coupled stochastic equations. The
interactions are divided into a hierarchy of groups with adiabatically
separated and monotonically increasing time-scales, representing sub-routines
of the system programme of decreasing volatility. We solve this model in
equilibrium, assuming ergodicity at every level, and find as our
replica-symmetric solution a formalism with a structure similar but not
identical to Parisi's -step replica symmetry breaking scheme. Apart from
differences in details of the equations (due to the fact that here
interactions, rather than spins, are grouped into clusters with different
time-scales), in the present model the block sizes of the emerging
ultrametric solution are not restricted to the interval , but are
independent control parameters, defined in terms of the noise strengths of the
various levels in the hierarchy, which can take any value in [0,\infty\ket.
This is shown to lead to extremely rich phase diagrams, with an abundance of
first-order transitions especially when the level of stochasticity in the
interaction dynamics is chosen to be low.Comment: 53 pages, 19 figures. Submitted to J. Phys.
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