2,808 research outputs found
Between-day reliability of IMU-derived spine control metrics in patients with low back pain
Inertial measurement units (IMUs) are a potentially useful tool for clinicians and researchers in assessing spine movement biomechanics and neuromuscular control patterns. This study assessed the between-day reliability of the HIKOB FOX IMU in measuring local dynamic stability (LDS) and variability of trunk movements in patients with chronic low back pain (LBP). The local divergence exponent (λmax) was used to quantify LDS and the mean standard deviation (MeanSD) between cycles was used to quantify variability during 30 repetitive cycles of flexion/extension, rotation, and complex movement tasks. For λmax the average coefficient of variation (CV) was ~10% in the flexion/extension and rotation tasks, and all CV values were <20% when also including the complex task. ICC values for λmax ranged from 0.28 to 0.81. Reliability of λmax was similar between the pelvis and thorax segments (CV: ~10%, ICC: 0.48–0.78) and worse for the lumbar spine (CV: ~15%, ICC: 0.28–0.59). The CV for MeanSD was typically in the range of 20–30%, with even greater CV in the non-primary axes during each task (30–52%). Similarly, ICC values were lowest about the anterior-posterior axis in the flexion/extension task (ICC: 0.15–0.29) and largest about the longitudinal axis in the rotation task (ICC: 0.76–0.88). The moderate between-day reliability of λmax in the sagittal and transverse planes offers improvement over manual and subjective tests with poor reliability that are currently used in clinics. The minimal detectable differences presented give a threshold for change in research and rehabilitation in patients with LBP
Supersymmetric minisuperspace with non-vanishing fermion number
The Lagrangean of supergravity is dimensionally reduced to one
(time-like) dimension assuming spatial homogeneity of any Bianchi type within
class A of the classification of Ellis and McCallum. The algebra of the
supersymmetry generators, the Lorentz generators, the diffeomorphism generators
and the Hamiltonian generator is determined and found to close. In contrast to
earlier work, infinitely many physical states with non-vanishing even fermion
number are found to exist in these models, indicating that minisuperspace
models in supergravity may be just as useful as in pure gravity.Comment: 4 page
The Kingfish’s Mineral Legacy: An Analysis of the Legality ofState Mineral Leases Granted to W.T. Burton and JamesA. Noe During the Years 1934–1936 and Their Relevanceto Former United States Senator and Louisiana GovernorHuey P. Long
An oxygen isotope test for the origin of Archean mantle roots
The origin of the peridotites that form cratonic mantle roots is a central issue in understanding the history and survival of Earth’s oldest continents. A long-standing hypothesis holds that the unusual bulk compositions of some cratonic peridotites stem from their origin as subducted oceanic serpentinite, dehydrated during subduction to form rigid buoyant keels (Schulze, 1986; Canil and Lee, 2009). We present oxygen isotope data from 93 mantle peridotites from five different Archean cratons to evaluate their possible origin as serpentinites. Cratonic mantle peridotite shows remarkably uniform δ18O values, identical to modern MORB-source mantle, that do not vary with bulk rock Si-enrichment or Ca-depletion. These data clearly conflict with any model for cratonic lithosphere that invokes serpentinite as a protolith for cratonic peridotite, and place additional constraints on cratonic mantle origins. We posit that the uniform δ18O was produced by sub-arc and/or MOR depletion processes and that the Si-enriched nature of some samples is unlikely to be related to slab melt infiltration. Instead, we suggest a peridotitic source of Si-enrichment, derived from ascending mantle melts, or a water-fluxed depleted mantle. These variably Si-enriched, cratonic mantle protoliths were then collisionally compressed into the thick cratonic roots that have protected Earth’s oldest continental crust for over 2.5 Gyr
Supersymmetric Homogeneous Quantum Cosmologies Coupled to a Scalar Field
Recent work on supersymmetric Bianchi type IX cosmologies coupled to a
scalar field is extended to a general treatment of homogeneous quantum
cosmologies with explicitely solvable momentum constraints, i.e. Bianchi types
I, II, VII, VIII besides the Bianchi type IX, and special cases, namely the
Friedmann universes, the Kantowski-Sachs space, and Taub-NUT space. Besides the
earlier explicit solution of the Wheeler DeWitt equation for Bianchi type IX,
describing a virtual wormhole fluctuation, an additional explicit solution is
given and identified with the `no-boundary state'.Comment: 23 PAGE
Quantization of the Bianchi type-IX model in supergravity with a cosmological constant
Diagonal Bianchi type-IX models are studied in the quantum theory of supergravity with a cosmological constant. It is shown, by imposing the
supersymmetry and Lorentz quantum constraints, that there are no physical
quantum states in this model. The Friedmann model in supergravity
with cosmological constant does admit quantum states. However, the Bianchi
type-IX model provides a better guide to the behaviour of a generic state,
since more gravitino modes are available to be excited. These results indicate
that there may be no physical quantum states in the full theory of
supergravity with a non-zero cosmological constant. are available to be
excited. These results indicate that there may be no physical quantum states in
the full theory of supergravity with a non-zero cosmological
constant.Comment: 17 pages report DAMTP R93/3
quantum cosmological solutions for Class A Bianchi Models
We find solutions for quantum Class A Bianchi models of the form generalizing the results obtained by Moncrief and Ryan in
standard quantum cosmology. For the II and IX Bianchi models there are other
solutions , to the Hamilton-Jacobi
equation for which is necessarely zero, in contrast with solutions
found in supersymmetric quantum cosmology.Comment: 15 pages, Late
"Not wishing to be the white rhino in the crowd" : disability-disclosure at University
This article reports on a qualitative study identifying the drivers for and boundaries to disability-disclosure in interability interactions as experienced by 13 students with physical impairments at five Belgian higher education institutions. Through surveys and in-depth interviews, the study explored whether the students experience, prefer, and expect differences in communication about their impairments with temporarily able-bodied peers, instructors, and staff. Interviews provided insight into the nuances of disclosure and topic avoidance decisions that differ by disclosure target: disabilitydisclosure is mainly a balancing act between fulfilling physical needs and maintaining a normal, positive identity. The visibility of impairments seems to play a minor role in the students’ initial orientation toward disclosing. The functions of disability-disclosure as posited by the Communication Predicament of Disability Model and the CARE-keys to effective interability communication (i.e., Contact, Ask, Respect, Empathy) are discussed as well as the implications of the findings for Communication Accommodation Theory
The Cosmological Probability Density Function for Bianchi Class A Models in Quantum Supergravity
Nicolai's theorem suggests a simple stochastic interpetation for
supersymmetric Euclidean quantum theories, without requiring any inner product
to be defined on the space of states. In order to apply this idea to
supergravity, we first reduce to a one-dimensional theory with local
supersymmetry by the imposition of homogeneity conditions. We then make the
supersymmetry rigid by imposing gauge conditions, and quantise to obtain the
evolution equation for a time-dependent wave function. Owing to the inclusion
of a certain boundary term in the classical action, and a careful treatment of
the initial conditions, the evolution equation has the form of a Fokker-Planck
equation. Of particular interest is the static solution, as this satisfies all
the standard quantum constraints. This is naturally interpreted as a
cosmological probability density function, and is found to coincide with the
square of the magnitude of the conventional wave function for the wormhole
state.Comment: 22 pages, Late
Differences in intracellular localisation of ANKH mutants that relate to mechanisms of calcium pyrophosphate deposition disease and craniometaphyseal dysplasia
ANKH mutations are associated with calcium pyrophosphate deposition disease and craniometaphyseal dysplasia. This study investigated the effects of these ANKH mutants on cellular localisation and associated biochemistry. We generated four ANKH overexpression-plasmids containing either calcium pyrophosphate deposition disease or craniometaphyseal dysplasia linked mutations: P5L, E490del and S375del, G389R. They were transfected into CH-8 articular chondrocytes and HEK293 cells. The ANKH mutants dynamic differential localisations were imaged and we investigated the interactions with the autophagy marker LC3. Extracellular inorganic pyrophosphate, mineralization, ENPP1 activity expression of ENPP1, TNAP and PIT-1 were measured. P5L delayed cell membrane localisation but once recruited into the membrane it increased extracellular inorganic pyrophosphate, mineralization, and ENPP1 activity. E490del remained mostly cytoplasmic, forming punctate co-localisations with LC3, increased mineralization, ENPP1 and ENPP1 activity with an initial but unsustained increase in TNAP and PIT-1. S375del trended to decrease extracellular inorganic pyrophosphate, increase mineralization. G389R delayed cell membrane localisation, trended to decrease extracellular inorganic pyrophosphate, increased mineralization and co-localised with LC3. Our results demonstrate a link between pathological localisation of ANKH mutants with different degrees in mineralization. Furthermore, mutant ANKH functions are related to synthesis of defective proteins, inorganic pyrophosphate transport, ENPP1 activity and expression of ENPP1, TNAP and PIT-1
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