244 research outputs found
Pre-hospital delay in acute myocardial infarction: judgement of symptoms and resistance to pain
Predicting Clinical Outcome of Stroke Patients with Tractographic Feature
The volume of stroke lesion is the gold standard for predicting the clinical
outcome of stroke patients. However, the presence of stroke lesion may cause
neural disruptions to other brain regions, and these potentially damaged
regions may affect the clinical outcome of stroke patients. In this paper, we
introduce the tractographic feature to capture these potentially damaged
regions and predict the modified Rankin Scale (mRS), which is a widely used
outcome measure in stroke clinical trials. The tractographic feature is built
from the stroke lesion and average connectome information from a group of
normal subjects. The tractographic feature takes into account different
functional regions that may be affected by the stroke, thus complementing the
commonly used stroke volume features. The proposed tractographic feature is
tested on a public stroke benchmark Ischemic Stroke Lesion Segmentation 2017
and achieves higher accuracy than the stroke volume and the state-of-the-art
feature on predicting the mRS grades of stroke patients. In addition, the
tractographic feature also yields a lower average absolute error than the
commonly used stroke volume feature.Comment: 12 pages, 4 figures, 3 tables. Accepted by MICCAI-BrainLesion 2019 as
an oral presentatio
Gravity waves and the LHC: Towards high-scale inflation with low-energy SUSY
It has been argued that rather generic features of string-inspired
inflationary theories with low-energy supersymmetry (SUSY) make it difficult to
achieve inflation with a Hubble scale H > m_{3/2}, where m_{3/2} is the
gravitino mass in the SUSY-breaking vacuum state. We present a class of
string-inspired supergravity realizations of chaotic inflation where a simple,
dynamical mechanism yields hierarchically small scales of post-inflationary
supersymmetry breaking. Within these toy models we can easily achieve small
ratios between m_{3/2} and the Hubble scale of inflation. This is possible
because the expectation value of the superpotential relaxes from large to
small values during the course of inflation. However, our toy models do not
provide a reasonable fit to cosmological data if one sets the SUSY-breaking
scale to m_{3/2} < TeV. Our work is a small step towards relieving the apparent
tension between high-scale inflation and low-scale supersymmetry breaking in
string compactifications.Comment: 21+1 pages, 5 figures, LaTeX, v2: added references, v3: very minor
changes, version to appear in JHE
No differences in in vivo kinematics between six different types of knee prostheses
Purpose: The aim of this study was to compare a broad range of total knee prostheses with different design parameters to determine whether in vivo kinematics was consistently related to design. The hypothesis was that there are no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Methods: At two sites, data were collected by a single observer on 52 knees (49 subjects with rheumatoid arthritis or osteoarthritis). Six different total knee prostheses were used: multi-radius, single-radius, fixed-bearing, mobilebearing, posterior-stabilized, cruciate retaining and cruciate sacrificing. Knee kinematics was recorded using fluoroscopy as the patients performed a step-up motion. Results: There was a significant effect of prosthetic design on all outcome parameters; however, post hoc tests showed that the NexGen group was responsible for 80% of the significant values. The range of knee flexion was much smaller in this group, resulting in smaller anterior-posterior translations and rotations. Conclusion: Despite kinematics being generally consistent with the kinematics intended by their design, there were no clear recognizable differences in in vivo kinematics between different design parameters or prostheses. Hence, the differences in design parameters or prostheses are not distinct enough to have an effect on clinical outcome of patients.Biomechanical EngineeringMechanical, Maritime and Materials Engineerin
D-brane potentials in the warped resolved conifold and natural inflation
In this paper we obtain a model of Natural Inflation from string theory with
a Planckian decay constant. We investigate D-brane dynamics in the background
of the warped resolved conifold (WRC) throat approximation of Type IIB string
compactifications on Calabi-Yau manifolds. When we glue the throat to a compact
bulk Calabi-Yau, we generate a D-brane potential which is a solution to the
Laplace equation on the resolved conifold. We can exactly solve this equation,
including dependence on the angular coordinates. The solutions are valid down
to the tip of the resolved conifold, which is not the case for the more
commonly used deformed conifold. This allows us to exploit the effect of the
warping, which is strongest at the tip. We inflate near the tip using an
angular coordinate of a D5-brane in the WRC which has a discrete shift
symmetry, and feels a cosine potential, giving us a model of Natural Inflation,
from which it is possible to get a Planckian decay constant whilst maintaining
control over the backreaction. This is because the decay constant for a wrapped
brane contains powers of the warp factor, and so can be made large, while the
wrapping parameter can be kept small enough so that backreaction is under
control.Comment: 41 pages, 3 appendices, 1 figure, PDFLaTex; various clarifications
added along with a new appendix on b-axions and wrapped D5 branes;version
matches the one published in JHE
Superconformal Yang-Mills quantum mechanics and Calogero model with OSp(N|2,R) symmetry
In spacetime dimension two, pure Yang-Mills possesses no physical degrees of
freedom, and consequently it admits a supersymmetric extension to couple to an
arbitrary number, N say, of Majorana-Weyl gauginos. This results in (N,0) super
Yang-Mills. Further, its dimensional reduction to mechanics doubles the number
of supersymmetries, from N to N+N, to include conformal supercharges, and leads
to a superconformal Yang-Mills quantum mechanics with symmetry group
OSp(N|2,R). We comment on its connection to AdS_2 \times S^{N-1} and reduction
to a supersymmetric Calogero model.Comment: 1+28 pages, no figure; Refs added. To appear in JHE
Strange Attractors in Dissipative Nambu Mechanics : Classical and Quantum Aspects
We extend the framework of Nambu-Hamiltonian Mechanics to include dissipation
in phase space. We demonstrate that it accommodates the phase space
dynamics of low dimensional dissipative systems such as the much studied Lorenz
and R\"{o}ssler Strange attractors, as well as the more recent constructions of
Chen and Leipnik-Newton. The rotational, volume preserving part of the flow
preserves in time a family of two intersecting surfaces, the so called {\em
Nambu Hamiltonians}. They foliate the entire phase space and are, in turn,
deformed in time by Dissipation which represents their irrotational part of the
flow. It is given by the gradient of a scalar function and is responsible for
the emergence of the Strange Attractors.
Based on our recent work on Quantum Nambu Mechanics, we provide an explicit
quantization of the Lorenz attractor through the introduction of
Non-commutative phase space coordinates as Hermitian matrices in
. They satisfy the commutation relations induced by one of the two
Nambu Hamiltonians, the second one generating a unique time evolution.
Dissipation is incorporated quantum mechanically in a self-consistent way
having the correct classical limit without the introduction of external degrees
of freedom. Due to its volume phase space contraction it violates the quantum
commutation relations. We demonstrate that the Heisenberg-Nambu evolution
equations for the Quantum Lorenz system give rise to an attracting ellipsoid in
the dimensional phase space.Comment: 35 pages, 4 figures, LaTe
Esophageal and tracheobronchial foreign bodies in infants and children
In an effort to improve the diagnosis and management of children with aspiration or ingestion of foreign bodies we reviewed 100 consecutive cases of esophageal (49) or tracheobronchial (51) foreign bodies occurring over a 6-year period. While the incidence of positive physical findings in the esophageal group was low, the combination of plain and contrast radiography was positive in 96% (47/49). Of the patients with tracheobronchial foreign body, 78% (40/51) had lateralizing signs on physical examination and 80% (41/51) had abnormal inspiratory/expiratory radiographs. Disimpaction of esophageal foreign bodies was carried out using a combination of techniques with 100% success and no complications. All cases of tracheobronchial foreign bodies were managed with the rigid bronchoscope with 98% success (50/51) using a variety of instruments. Complications secondary to the foreign body itself rather than its management were seen in 9 patients, and were often due to a delay in diagnosis. A careful history and physical examination along with appropriate radiographic studies will result in a correct diagnosis in virtually all cases of esophageal and tracheobronchial foreign bodies. A liberal indication for endoscopy using an approach tailored to the particular case will almost always be successful.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47159/1/383_2004_Article_BF00175647.pd
GHQ increases among Scottish 15 year olds 1987ā2006
BACKGROUND:
Increases in a number of psychosocial disorders have been identified among Western youth in the second half of the Twentieth century. However findings are not consistent, trends are complex, and comparisons over time are hampered by methodological problems.
METHODS:
Data were drawn from three samples identical in respect of age (15 years), school year (final year of statutory schooling) and geographical location (the West of Scotland). Each sample was administered the 12-item General Health Questionnaire, a measure of self-report psychological distress, in 1987 (N = 505), 1999 (N = 2,196) and 2006 (N = 3,194). Analyses were conducted to examine changes in: GHQ 'caseness'; individual items; and factors, derived via confirmatory factor analysis representing (a) 'negative' and 'positive' items, and (b) 'anxiety and depression', 'loss of confidence or self-esteem' and 'anhedonia and social dysfunction'.
RESULTS:
Based on the standard (2/3) cut-off, 'caseness' rates in 1987, 1999 and 2006 were 12.7, 15.1 and 21.5% (males) and 18.8, 32.5 and 44.1% (females). Similar increases were observed with more stringent 'caseness' cut-offs. Examination of individual items showed some to have increased much more markedly over time than others. There were larger increases among females for all except two items and some evidence, among both genders, of steeper increases among 'negative' items compared with 'positive' ones. However, the differences in slope were very small compared with the overall increases in both types.
CONCLUSIONS:
Data from three samples identical in respect of age, school year and geographical location, show marked increases in GHQ-12 'caseness' among females between 1987 and 1999 and among both males and females between 1999 and 2006. Although slightly steeper increases in 'negative' items raise the possibility that endorsing such symptoms may have become more acceptable, these were small in comparison with increases in all dimensions of psychological distress. The next step is to identify causal explanations for the increases reported here
High serum levels of transforming growth factor Ī²1 are associated with increased cortical thickness in cingulate and right frontal areas in healthy subjects
ABSTRACT
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