4,410 research outputs found
Gesuspendeerde materie in de Schelde: evaluatie van een onderzoek van de ULB voor het Ministerie van Volksgezondheid
Multipartite entanglement in the Fenna-Matthews-Olson (FMO) pigment-protein complex
We investigate multipartite states in the Fenna-Matthews-Olson (FMO)
pigment-protein complex of the green sulfur bacteria using a Lorentzian
spectral density of the phonon reservoir fitted with typical parameter
estimates of the species, P. aestuarii. The evolution of the entanglement
measure of the excitonic W qubit states is evaluated in the picosecond time
range, showing increased revivals in the non-Markovian regime. Similar trends
are observed in the evolution dynamics of the Meyer-Wallach measure of the
N-exciton multipartite state, with results showing that multipartite
entanglement can last from 0.5 to 1 ps, between the Bchls of the FMO complex.
The teleportation and quantum information splitting fidelities associated with
the GHZ and W_A resource states of the excitonic qubit channels of the FMO
complex show that revivals in fidelities increase with the degree of
non-Markovian strength of the decoherent environment. Results indicate that
quantum information processing tasks involving teleportation followed by the
decodification process involving W_A states of the FMO complex, may play a
critical role during coherent oscillations at physiological temperatures.Comment: 16 pages, new figs, typo
International vs. National female tennis players: a comparison of upper and lower extremity functional asymmetries
Background:
Asymmetries have been reported to negatively impact sport performance. This study examined the magnitude and direction of whole-body functional asymmetry in international versus national female tennis players.
Methods:
Ten internationally and twelve nationally ranked tennis players participated. Upper extremity functional asymmetries (or side-to-side performance differences) were evaluated using handgrip strength, seated shot-put throw and plate tapping. Lower extremity functional asymmetries were determined using the single leg countermovement jump, single leg forward hop test, 6 m single leg hop test, 505 changes of direction (time and deficit), and Y-balance test (anterior, posteromedial, posterolateral). ANOVAs were used to compare the dominant (overall best or fastest result of a specific test) versus non-dominant performance values (best or fastest result of the corresponding extremity) within the internationally versus nationally ranked players. Functional asymmetry magnitudes differences (expressed as a %) were examined using Mann-Whitney U tests. Kappa coefficients examined the consistency as to which extremity performed dominantly across tests.
Results:
Significant asymmetries for every upper and lower extremity test were found. The functional asymmetry magnitude was significantly (p=0.020) higher on the single leg forward hop test for the nationally (6.3%) versus internationally ranked players (2.9%). Kappa coefficients showed perfect levels of consistency regarding all upper extremity tests (k=1.00), indicating true limb dominance whereas more variance was found as to which lower extremity performed dominantly across tests (k range=-0.067-0.174).
Conclusions:
The included female tennis players displayed significant whole-body functional asymmetries. Poor consistency as to which lower extremity performed dominantly across tests warrants individual asymmetry monitoring
Automated Verification of Quantum Protocols using MCMAS
We present a methodology for the automated verification of quantum protocols
using MCMAS, a symbolic model checker for multi-agent systems The method is
based on the logical framework developed by D'Hondt and Panangaden for
investigating epistemic and temporal properties, built on the model for
Distributed Measurement-based Quantum Computation (DMC), an extension of the
Measurement Calculus to distributed quantum systems. We describe the
translation map from DMC to interpreted systems, the typical formalism for
reasoning about time and knowledge in multi-agent systems. Then, we introduce
dmc2ispl, a compiler into the input language of the MCMAS model checker. We
demonstrate the technique by verifying the Quantum Teleportation Protocol, and
discuss the performance of the tool.Comment: In Proceedings QAPL 2012, arXiv:1207.055
Entanglement Equivalence of -qubit Symmetric States
We study the interconversion of multipartite symmetric -qubit states under
stochastic local operations and classical communication (SLOCC). We demonstrate
that if two symmetric states can be connected with a nonsymmetric invertible
local operation (ILO), then they belong necessarily to the separable, W, or GHZ
entanglement class, establishing a practical method of discriminating subsets
of entanglement classes. Furthermore, we prove that there always exists a
symmetric ILO connecting any pair of symmetric -qubit states equivalent
under SLOCC, simplifying the requirements for experimental implementations of
local interconversion of those states.Comment: Minor correction
The effects of pediatric obesity on dynamic joint malalignment during gait
Background: There is a greater prevalence of lower extremity malalignment in obese children during static posture; however, there has been less examination of dynamic joint function in this cohort. Therefore, the purpose of this study was to determine kinematic differences that exist between obese and non-obese children that would support previously reported static joint malalignment. Methods: Forty children were classified as obese (n=20) or non-obese (n=20). Lower extremity joint kinematics were collected during five walking trials at a self-selected pace. Peak joint displacement and amount of joint motion throughout the gait cycle (calculated as the integrated displacement curve) were analyzed for group differences. Findings: Non-obese children had greater peak knee and hip extension during gait; however, there were no group differences in the integrated sagittal displacement curve. Obese children had greater peak angular displacement and integrals of angular displacement for peak hip adduction, hip internal rotation, and foot abduction (toe-out) than non-obese children. Obese children also had greater peak knee external rotation than non-obese children. Interpretation: Non-obese children showed greater range of motion in the sagittal plane, particularly at the hip and knee. Frontal and transverse plane differences suggest that obese children function in a more genu valgum position than non-obese children. Staticmeasures of genu valgum have been previously associated with pediatric obesity; the findings indicate that there are also dynamic implications of said malalignment in obese children. Genu valgum presents increased risk of osteoarthritis for obese children and should be considered when prescribing weight bearing exercise to this cohort
The Measurement Calculus
Measurement-based quantum computation has emerged from the physics community
as a new approach to quantum computation where the notion of measurement is the
main driving force of computation. This is in contrast with the more
traditional circuit model which is based on unitary operations. Among
measurement-based quantum computation methods, the recently introduced one-way
quantum computer stands out as fundamental.
We develop a rigorous mathematical model underlying the one-way quantum
computer and present a concrete syntax and operational semantics for programs,
which we call patterns, and an algebra of these patterns derived from a
denotational semantics. More importantly, we present a calculus for reasoning
locally and compositionally about these patterns.
We present a rewrite theory and prove a general standardization theorem which
allows all patterns to be put in a semantically equivalent standard form.
Standardization has far-reaching consequences: a new physical architecture
based on performing all the entanglement in the beginning, parallelization by
exposing the dependency structure of measurements and expressiveness theorems.
Furthermore we formalize several other measurement-based models:
Teleportation, Phase and Pauli models and present compositional embeddings of
them into and from the one-way model. This allows us to transfer all the theory
we develop for the one-way model to these models. This shows that the framework
we have developed has a general impact on measurement-based computation and is
not just particular to the one-way quantum computer.Comment: 46 pages, 2 figures, Replacement of quant-ph/0412135v1, the new
version also include formalization of several other measurement-based models:
Teleportation, Phase and Pauli models and present compositional embeddings of
them into and from the one-way model. To appear in Journal of AC
Fauna Europaea: Gastrotricha.
Fauna Europaea provides a public web-service with an index of scientific names (including
important synonyms) of all living European land and freshwater animals, their geographical
distribution at country level (up to the Urals, excluding the Caucasus region), and some
additional information. The Fauna Europaea project covers about 230,000 taxonomic
names, including 130,000 accepted species and 14,000 accepted subspecies, which is
much more than the originally projected number of 100,000 species. This represents a
huge effort by more than 400 contributing specialists throughout Europe and is a unique
(standard) reference suitable for many users in science, government, industry, nature
conservation and education
The Expectation Monad in Quantum Foundations
The expectation monad is introduced abstractly via two composable
adjunctions, but concretely captures measures. It turns out to sit in between
known monads: on the one hand the distribution and ultrafilter monad, and on
the other hand the continuation monad. This expectation monad is used in two
probabilistic analogues of fundamental results of Manes and Gelfand for the
ultrafilter monad: algebras of the expectation monad are convex compact
Hausdorff spaces, and are dually equivalent to so-called Banach effect
algebras. These structures capture states and effects in quantum foundations,
and also the duality between them. Moreover, the approach leads to a new
re-formulation of Gleason's theorem, expressing that effects on a Hilbert space
are free effect modules on projections, obtained via tensoring with the unit
interval.Comment: In Proceedings QPL 2011, arXiv:1210.029
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