9,801 research outputs found
Materials investigation and tests for the development of space compatible electrical connectors, phase 1 Final report, 1 Jun. - 30 Nov. 1970
Digital pulse optimization for space compatible electric connector
Quantum information transfer for qutrits
We propose a scheme for the transfer of quantum information among distant
qutrits. We apply this scheme to the distribution of entanglement among distant
nodes and to the generation of multipartite antisymmetric states. We also
discuss applications to quantum secret sharing
Ultrafast control of donor-bound electron spins with single detuned optical pulses
The ability to control spins in semiconductors is important in a variety of
fields including spintronics and quantum information processing. Due to the
potentially fast dephasing times of spins in the solid state [1-3], spin
control operating on the picosecond or faster timescale may be necessary. Such
speeds, which are not possible to attain with standard electron spin resonance
(ESR) techniques based on microwave sources, can be attained with broadband
optical pulses. One promising ultrafast technique utilizes single broadband
pulses detuned from resonance in a three-level Lambda system [4]. This
attractive technique is robust against optical pulse imperfections and does not
require a fixed optical reference phase. Here we demonstrate the principle of
coherent manipulation of spins theoretically and experimentally. Using this
technique, donor-bound electron spin rotations with single-pulse areas
exceeding pi/4 and two-pulses areas exceeding pi/2 are demonstrated. We believe
the maximum pulse areas attained do not reflect a fundamental limit of the
technique and larger pulse areas could be achieved in other material systems.
This technique has applications from basic solid-state ESR spectroscopy to
arbitrary single-qubit rotations [4, 5] and bang-bang control[6] for quantum
computation.Comment: 15 pages, 4 figures, submitted 12/2008. Since the submission of this
work we have become aware of related work: J. Berezovsky, M. H. Mikkelsen, N.
G. Stoltz, L. A. Coldren, and D. D. Awschalom, Science 320: 349-352 (2008
Vibrational Relaxation and Redistribution Dynamics in Ruthenium(II) Polypyridyl-Based Charge-Transfer Excited States: A Combined Ultrafast Electronic and Infrared Absorption Study
Ultrafast time-resolved
electronic and infrared absorption measurements
have been carried out on a series of Ru(II) polypyridyl complexes
in an effort to delineate the dynamics of vibrational relaxation in
this class of charge transfer chromophores. Time-dependent density
functional theory calculations performed on compounds of the form
[Ru(CN-Me-bpy)x(bpy)3‑x]2+ (x = 1–3 for compounds 1–3, respectively, where CN-Me-bpy is
4,4′-dicyano-5,5′-dimethyl-2,2′-bipyridine and
bpy is 2,2′-bipyridine) reveal features in their charge-transfer
absorption envelopes that allow for selective excitation of the Ru(II)–(CN-Me-bpy)
moiety, the lowest-energy MLCT state(s) in each compound of the series.
Changes in band shape and amplitude of the time-resolved differential
electronic absorption data are ascribed to vibrational cooling in
the CN-Me-bpy-localized 3MLCT state with a time constant
of 8 ± 3 ps in all three compounds. This conclusion was corroborated
by picosecond time-resolved infrared absorption measurements; sharpening
of the CN stretch in the 3MLCT excited state was observed
with a time constant of 3.0 ± 1.5 ps in all three members of
the series. Electronic absorption data acquired at higher temporal
resolution revealed spectral modulation over the first 2 ps occurring
with a time constant of τ = 170 ± 50 fs, in compound 1; corresponding effects are significantly attenuated in compound 2 and virtually absent in compound 3. We assign
this feature to intramolecular vibrational redistribution (IVR) within
the 3MLCT state and represents a rare example of this process
being identified from time-resolved electronic absorption data for
this important class of chromophores
Development of the Variable Dexterity Test: construction, reliability and validity
Background/Aims: This article introduces a dexterity test designed to assess individual types of
dexterity used to carry out activities of daily living (ADL). The Variable Dexterity Test (VDT) was
developed as part of a wider study, the broader aim being to fully understand dexterity and its effect
on human-product interaction during ADL. This was done with a view to improve occupational therapy
methods when assessing dexterity and general hand function.
Methods: The control group consisted of 24 healthy participants. Estimates of reliability and validity
were evaluated in this pilot study. Inter-rater and test-retest reliability were assessed using a one-way
ANOVA. The validity of the test was estimated by correlating participants’ VDT scores with their
proficiency to complete four ADL task actions and a standardised dexterity test (Purdue Pegboard Test).
Results: The test produced consistent results among the control group with both a single assessor
(test‑retest reliability) and multiple assessors (inter‑rater reliability). High correlations between
participants’ VDT scores and proficiency to perform ADL were found for most of the subtests. There
was also a high correlation between participants’ scores from the Purdue Pegboard Test and the VDT.
Conclusions: The VDT proved to be a flexible, reliable and valid tool that assesses dexterity based on
ability to carry out ADL. Validity and reliability estimates show encouraging values, which recognises
that the VDT can be used as an accurate method to assess more than one type of dexterity.</p
E-learning interventions are comparable to user's manual in a randomized trial of training strategies for the AGREE II
<p>Abstract</p> <p>Background</p> <p>Practice guidelines (PGs) are systematically developed statements intended to assist in patient and practitioner decisions. The AGREE II is the revised tool for PG development, reporting, and evaluation, comprised of 23 items, two global rating scores, and a new User's Manual. In this study, we sought to develop, execute, and evaluate the impact of two internet interventions designed to accelerate the capacity of stakeholders to use the AGREE II.</p> <p>Methods</p> <p>Participants were randomized to one of three training conditions. 'Tutorial'--participants proceeded through the online tutorial with a virtual coach and reviewed a PDF copy of the AGREE II. 'Tutorial + Practice Exercise'--in addition to the Tutorial, participants also appraised a 'practice' PG. For the practice PG appraisal, participants received feedback on how their scores compared to expert norms and formative feedback if scores fell outside the predefined range. <it>'</it>AGREE II User's Manual PDF (control condition)'<it>--</it>participants reviewed a PDF copy of the AGREE II only. All participants evaluated a test PG using the AGREE II. Outcomes of interest were learners' performance, satisfaction, self-efficacy, mental effort, time-on-task, and perceptions of AGREE II.</p> <p>Results</p> <p>No differences emerged between training conditions on any of the outcome measures.</p> <p>Conclusions</p> <p>We believe these results can be explained by better than anticipated performance of the AGREE II PDF materials (control condition) or the participants' level of health methodology and PG experience rather than the failure of the online training interventions. Some data suggest the online tools may be useful for trainees new to this field; however, this requires further study.</p
Robot rights? Towards a social-relational justification of moral consideration \ud
Should we grant rights to artificially intelligent robots? Most current and near-future robots do not meet the hard criteria set by deontological and utilitarian theory. Virtue ethics can avoid this problem with its indirect approach. However, both direct and indirect arguments for moral consideration rest on ontological features of entities, an approach which incurs several problems. In response to these difficulties, this paper taps into a different conceptual resource in order to be able to grant some degree of moral consideration to some intelligent social robots: it sketches a novel argument for moral consideration based on social relations. It is shown that to further develop this argument we need to revise our existing ontological and social-political frameworks. It is suggested that we need a social ecology, which may be developed by engaging with Western ecology and Eastern worldviews. Although this relational turn raises many difficult issues and requires more work, this paper provides a rough outline of an alternative approach to moral consideration that can assist us in shaping our relations to intelligent robots and, by extension, to all artificial and biological entities that appear to us as more than instruments for our human purpose
2-Hydroxy-3-nitro-N-phenylbenzamide
The asymmetric unit of the title compound, C13H10N2O4, contains two crystallographically independent molecules. The aromatic rings are oriented at dihedral angles of 24.39 (3) and 7.47 (3)° in the two molecules and intramolecular N—H⋯O and O—H⋯O hydrogen bonds result in the formation of two planar six-membered rings. In the crystal structure, intermolecular O—H⋯O and C—H⋯O hydrogen bonds link the molecules into chains, forming R
2
2(10) ring motifs. Weak π–π contacts between the benzene and phenyl rings [centroid–centroid distance = 3.955 (3) Å] may further stabilize the structure
Vacuum Stability, Perturbativity, and Scalar Singlet Dark Matter
We analyze the one-loop vacuum stability and perturbativity bounds on a
singlet extension of the Standard Model (SM) scalar sector containing a scalar
dark matter candidate. We show that the presence of the singlet-doublet quartic
interaction relaxes the vacuum stability lower bound on the SM Higgs mass as a
function of the cutoff and lowers the corresponding upper bound based on
perturbativity considerations. We also find that vacuum stability requirements
may place a lower bound on the singlet dark matter mass for given singlet
quartic self coupling, leading to restrictions on the parameter space
consistent with the observed relic density. We argue that discovery of a light
singlet scalar dark matter particle could provide indirect information on the
singlet quartic self-coupling.Comment: 25 pages, 10 figures; v2 - fixed minor typos; v3 - added to text
discussions of other references, changed coloring of figures for easier black
and white viewin
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