7,064 research outputs found
The Paternalistic Relationship: Authenticity and credibility as a source of healthy relationships
This article explores the how the Paternalistic Leadership model can be viewed as part of a relationship-based paradigm of leadership, and can incorporate concepts such as credibility and authenticity. The review highlights the need to understand paternalistic leadership as an approach to establishing productive relationships within a cultural context, with implications for researchers and practitioners in both collectivist and individualistic cultures
Behavioural clusters and predictors of performance during recovery from stroke
We examined the patterns and variability of recovery post-stroke in multiple behavioral domains. A large cohort of first time stroke patients with heterogeneous lesions was studied prospectively and longitudinally at 1-2 weeks, 3 months and one year post-injury with structural MRI to measure lesion anatomy and in-depth neuropsychological assessment. Impairment was described at all timepoints by a few clusters of correlated deficits. The time course and magnitude of recovery was similar across domains, with change scores largely proportional to the initial deficit and most recovery occurring within the first three months. Damage to specific white matter tracts produced poorer recovery over several domains: attention and superior longitudinal fasciculus II/III, language and posterior arcuate fasciculus, motor and corticospinal tract. Finally, after accounting for the severity of the initial deficit, language and visual memory recovery/outcome was worse with lower education, while the occurrence of multiple deficits negatively impacted attention recovery
Revivals of Coherence in Chaotic Atom-Optics Billiards
We investigate the coherence properties of thermal atoms confined in optical
dipole traps where the underlying classical dynamics is chaotic. A perturbative
expression derived for the coherence of the echo scheme of [Andersen et. al.,
Phys. Rev. Lett. 90, 023001 (2003)] shows it is a function of the survival
probability or fidelity of eigenstates of the motion of the atoms in the trap.
The echo coherence and the survival probability display "system specific"
features, even when the underlying classical dynamics is chaotic. In
particular, partial revivals in the echo signal and the survival probability
are found for a small shift of the potential. Next, a "semi-classical"
expression for the averaged echo signal is presented and used to calculate the
echo signal for atoms in a light sheet wedge billiard. Revivals in the echo
coherence are found in this system, indicating they may be a generic feature of
dipole traps
A double-helix neutron detector using micron-size B-10 powder
A double-helix electrode configuration is combined with a B powder
coating technique to build large-area (9 in 36 in) neutron detectors.
The neutron detection efficiency for each of the four prototypes is comparable
to a single 2-bar He drift tube of the same length (36 in). One unit has
been operational continuously for 18 months and the change of efficiency is
less than 1%. An analytic model for pulse heigh spectra is described and the
predicted mean film thickness agrees with the experiment to within 30%. Further
detector optimization is possible through film texture, power size, moderator
box and gas. The estimated production cost per unit is less than 3k US\$ and
the technology is thus suitable for deployment in large numbers
Supersymmetric Electroweak Baryogenesis Via Resonant Sfermion Sources
We calculate the baryon asymmetry produced at the electroweak phase
transition by quasi-degenerate third generation sfermions in the minimal
supersymmetric extension of the Standard Model. We evaluate constraints from
Higgs searches, from collider searches for supersymmetric particles, and from
null searches for the permanent electric dipole moment (EDM) of the electron,
of the neutron and of atoms. We find that resonant sfermion sources can in
principle provide a large enough baryon asymmetry in various corners of the
sfermion parameter space, and we focus, in particular, on the case of large
, where third-generation down-type (s)fermions become relevant. We
show that in the case of stop and sbottom sources, the viable parameter space
is ruled out by constraints from the non-observation of the Mercury EDM. We
introduce a new class of CP violating sources, quasi-degenerate staus, that
escapes current EDM constraints while providing large enough net chiral
currents to achieve successful "slepton-mediated" electroweak baryogenesis.Comment: 35 pages, 9 figures; v2: several revisions, but conclusions
unchanged. Matches version published in PR
Distribution of interference in random quantum algorithms
We study the amount of interference in random quantum algorithms using a
recently derived quantitative measure of interference. To this end we introduce
two random circuit ensembles composed of random sequences of quantum gates from
a universal set, mimicking quantum algorithms in the quantum circuit
representation. We show numerically that these ensembles converge to the
well--known circular unitary ensemble (CUE) for general complex quantum
algorithms, and to the Haar orthogonal ensemble (HOE) for real quantum
algorithms. We provide exact analytical formulas for the average and typical
interference in the circular ensembles, and show that for sufficiently large
numbers of qubits a random quantum algorithm uses with probability close to one
an amount of interference approximately equal to the dimension of the Hilbert
space. As a by-product, we offer a new way of efficiently constructing random
operators from the Haar measures of CUE or HOE in a high dimensional Hilbert
space using universal sets of quantum gates.Comment: 14 pages revtex, 11 eps figure
Kepler Mission Stellar and Instrument Noise Properties Revisited
An earlier study of the Kepler Mission noise properties on time scales of
primary relevance to detection of exoplanet transits found that higher than
expected noise followed to a large extent from the stars, rather than
instrument or data analysis performance. The earlier study over the first six
quarters of Kepler data is extended to the full four years ultimately
comprising the mission. Efforts to improve the pipeline data analysis have been
successful in reducing noise levels modestly as evidenced by smaller values
derived from the current data products. The new analyses of noise properties on
transit time scales show significant changes in the component attributed to
instrument and data analysis, with essentially no change in the inferred
stellar noise. We also extend the analyses to time scales of several days,
instead of several hours to better sample stellar noise that follows from
magnetic activity. On the longer time scale there is a shift in stellar noise
for solar-type stars to smaller values in comparison to solar values.Comment: 10 pages, 8 figures, accepted by A
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