385 research outputs found
Reduced cingulate gyrus volume in Cavalier King Charles Spaniels with syringomyelia and neuropathic pain revealed by voxel-based morphometry: a pilot study
Objective: Pathomorphological alterations of the central nervous system in dogs, such as syringomyelia and Chiari-like malformation, can cause cranial and cervical hyperesthesia and neuropathic pain. The long-term activity of the pain network can induce functional alteration and eventually even morphological changes in the pain network. This may happen especially in the prefrontal and cingulate cortex, where atrophy of the gray matter (GM) was observed in humans with chronic pain, irrespective of the nature of the pain syndrome. We tested the hypothesis that Cavalier King Charles Spaniels (CKCS) with Chiari-like malformation and associated syringomyelia (SM) and pain show cerebral morphological differences compared to animals without signs of syringomyelia and pain.
Methods: Volumetric datasets of 28 different brain structures were analyzed in a retrospective manner, including voxel-based morphometry, using magnetic resonance imaging data obtained from 41 dogs.
Results: Volumetric analyses revealed a decrease in GM volumes in the cingulate gyrus (CG) in CKCS with SM and chronic pain when normalized to brain volume. This finding was supported by voxel-based morphometry, which showed a cluster of significance within the CG.
Conclusion: GM atrophy in the CG is associated with chronic pain and thus may serve as an objective readout parameter for the diagnosis or treatment of canine pain syndromes
Sound Multi-Party Business Protocols for Service Networks
Service networks comprise large numbers of long-running, highly dynamic complex end-to-end service interactions reflecting asynchronous message flows that typically transcend several organizations and span several geographical locations. At the communication level, service network business protocols can be flexible ranging from conventional inter-organizational point-to-point service interactions to fully blown dynamic multi-party interactions of global reach within which each participant may contribute its activities and services. In this paper we introduce a formal framework enriched with temporal constraints to describe multiparty business protocols for service networks. We extend this framework with the notion of multi-party business protocol soundness and show how it is possible to execute a multi-party protocol consistently in a completely distributed manner while guaranteeing eventual termination
Temperature dependent optical conductivity of undoped cuprates with weak exchange
The optical conductivity sigma(omega) is calculated at finite temperature T
for CuO_2 chain clusters within a pd-Hubbard model. Data at T = 300 K for
Li_2CuO_2 are reanalyzed within this approach. The relative weights of
Zhang-Rice singlet and triplet charge excitations near 2.5 and 4 eV,
respectively, depend strongly on T, and a rather dramatic dependence of
sigma(omega) on the ratio of the first to second neighbor exchange integrals is
predicted. On the basis of these results, information about exchange
interactionsfor frustrated edge-shared cuprates can be obtained from
T-dependent optical spectra. Our results are also relevant for magnetically
weakly coupled wide-gap insulators in general.Comment: 5 pages, 3 figure
Highly Dispersive Spin Excitations in the Chain Cuprate Li2CuO2
We present an inelastic neutron scattering investigation of Li2CuO2 detecting
the long sought quasi-1D magnetic excitations with a large dispersion along the
CuO2-chains studied up to 25 meV. The total dispersion is governed by a
surprisingly large ferromagnetic (FM) nearest-neighbor exchange integral
J1=-228 K. An anomalous quartic dispersion near the zone center and a
pronounced minimum near (0,0.11,0.5) r.l.u. (corresponding to a spiral
excitation with a pitch angle about 41 degree point to the vicinity of a 3D
FM-spiral critical point. The leading exchange couplings are obtained applying
standard linear spin-wave theory. The 2nd neighbor inter-chain interaction
suppresses a spiral state and drives the FM in-chain ordering below the Ne'el
temperature. The obtained exchange parameters are in agreement with the results
for a realistic five-band extended Hubbard Cu 3d O 2p model and L(S)DA+U
predictions.Comment: 6 pages, 4 figures, submitted to Europhys. Let
Brain glucose utilization in systemic lupus erythematosus with neuropsychiatric symptoms: A controlled positron emission tomography study
In contrast to morphological imaging [such as magnetic resonance imaging (MRI) or computed tomography], functional imaging may be of advantage in the detection of brain abnormalities in cases of neuropsychiatric systemic lupus erythematosus (SLE). Therefore, we studied 13 patients (aged 40±14 years, 11 female, 2 male) with neuropsychiatric SLE who met four of the American Rheumatism Association criteria for the classification of SLE. Ten clinically and neurologically healthy volunteers served as controls (aged 40±12 years, 5 female, 5 male). Both groups were investigated using fluorine-18-labelled fluorodeoxyglucose brain positron emission tomography (PET) and cranial MRI. The normal controls and 11 of the 13 patients showed normal MRI scans. However, PET scan was abnormal in all 13 SLE patients. Significant group-to-group differences in the glucose metabolic index (GMI=region of interest uptake/global uptake at the level of the basal ganglia and thalamus) were found in the parieto-occipital region on both sides: the GMI of the parieto-occipital region on the right side was 0.922±0.045 in patients and 1.066±0.081 in controls (P<0.0001, Mann WhitneyU test), while on the left side it was 0.892±0.060 in patients and 1.034±0.051 in controls (P=0.0002). Parietooccipital hypometabolism is a conspicuous finding in mainly MRI-negative neuropsychiatric SLE. As the parieto-occipital region is located at the boundary of blood supply of all three major arteries, it could be the most vulnerable zone of the cerebrum and may be affected at an early stage of the cerebrovascular diseas
Reduced cingulate gyrus volume in Cavalier King Charles Spaniels with syringomyelia and neuropathic pain revealed by voxel-based morphometry : a pilot study
Objective: Pathomorphological alterations of the central nervous system in dogs, such as syringomyelia and Chiari-like malformation, can cause cranial and cervical hyperesthesia and neuropathic pain. The long-term activity of the pain network can induce functional alteration and eventually even morphological changes in the pain network. This may happen especially in the prefrontal and cingulate cortex, where atrophy of the gray matter (GM) was observed in humans with chronic pain, irrespective of the nature of the pain syndrome. We tested the hypothesis that Cavalier King Charles Spaniels (CKCS) with Chiari-like malformation and associated syringomyelia (SM) and pain show cerebral morphological differences compared to animals without signs of syringomyelia and pain.
Methods: Volumetric datasets of 28 different brain structures were analyzed in a retrospective manner, including voxel-based morphometry, using magnetic resonance imaging data obtained from 41 dogs.
Results: Volumetric analyses revealed a decrease in GM volumes in the cingulate gyrus (CG) in CKCS with SM and chronic pain when normalized to brain volume. This finding was supported by voxel-based morphometry, which showed a cluster of significance within the CG.
Conclusion: GM atrophy in the CG is associated with chronic pain and thus may serve as an objective readout parameter for the diagnosis or treatment of canine pain syndromes
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Winners and losers: German equity mutual funds
We investigate the performance of winners and losers for German equity mutual funds (1990–2009), using empirical order statistics. When using gross returns and the Fama–French three-factor model, the number of statistically significant positive alpha funds is zero but increases markedly when market timing variables are added. However, when using a ‘total performance’ measure (which incorporates both alpha and the contribution of market timing), the number of statistically significant winner funds falls to zero. The latter is consistent with the bias in estimated alphas in the presence of market timing. We also find that many poorly performing funds are unskilled rather than unlucky
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