Leukoencephalomyelopathy in a Rottweiler dogs - two ca ses report

Proceeding

Classification of inter-subject fMRI data based on graph kernels

The analysis of human brain connectivity networks has become an increasingly prevalent task in neuroimaging. A few recent studies have shown the possibility of decoding brain states based on brain graph classification. Graph kernels have emerged as a powerful tool for graph comparison that allows the direct use of machine learning classifiers on brain graph collections. They allow classifying graphs with different number of nodes and therefore the inter-subject analysis without any kind of previous alignment of individual subject's data. Using whole-brain fMRI data, in this paper we present a method based on graph kernels that provides above-chance accuracy results for the inter-subject discrimination of two different types of auditory stimuli. We focus our research on determining whether this method is sensitive to the relational information in the data. Indeed, we show that the discriminative information is not only coming from topological features of the graphs like node degree distribution, but also from more complex relational patterns in the neighborhood of each node. Moreover, we investigate the suitability of two different graph representation methods, both based on data-driven parcellation techniques. Finally, we study the influence of noisy connections in our graphs and provide a way to alleviate this problem

Waves and Solitons in the Continuum Limit of the Calogero-Sutherland Model

We examine a collection of particles interacting with inverse-square two-body potentials in the thermodynamic limit. We find explicit large-amplitude density waves and soliton solutions for the motion of the system. Waves can be constructed as coherent states of either solitons or phonons. Therefore, either solitons or phonons can be considered as the fundamental excitations. The generic wave is shown to correspond to a two-band state in the quantum description of the system, while the limiting cases of solitons and phonons correspond to particle and hole excitations.Comment: Version to appear in Physical Rerview Letters; contains some new results and explanation

Comment on ``Low-dimensional Bose liquids: beyond the Gross-Pitaevskii approximation''

This is a comment on the work of Kolomeisky et al., Phys. Rev. Lett. 85, 1146 (2000). We point out that they are using the wrong form of the energy functional for one-dimensional fermions. We point out two possible forms of the energy functional, both of which can be derived from first principles but using different methods. One is obtained from the collective field theory method, while the other is derived from the extended Thomas-Fermi method. These two forms of the energy functional do not support the soliton solutions which are obtained by Kolomeisky et al.Comment: Revtex, 2 page

Density Correlation Functions in Calogero Sutherland Models

Using arguments from two dimensional Yang-Mills theory and the collective coordinate formulation of the Calogero-Sutherland model, we conjecture the dynamical density correlation function for coupling $l$ and $1/l$, where $l$ is an integer. We present overwhelming evidence that the conjecture is indeed correct.Comment: 12 pages phyzzx, CERN-TH/94.7243 One reference change

Parallel Workflows for Data-Driven Structural Equation Modeling in Functional Neuroimaging

We present a computational framework suitable for a data-driven approach to structural equation modeling (SEM) and describe several workflows for modeling functional magnetic resonance imaging (fMRI) data within this framework. The Computational Neuroscience Applications Research Infrastructure (CNARI) employs a high-level scripting language called Swift, which is capable of spawning hundreds of thousands of simultaneous R processes (R Development Core Team, 2008), consisting of self-contained SEMs, on a high performance computing system (HPC). These self-contained R processing jobs are data objects generated by OpenMx, a plug-in for R, which can generate a single model object containing the matrices and algebraic information necessary to estimate parameters of the model. With such an infrastructure in place a structural modeler may begin to investigate exhaustive searches of the model space. Specific applications of the infrastructure, statistics related to model fit, and limitations are discussed in relation to exhaustive SEM. In particular, we discuss how workflow management techniques can help to solve large computational problems in neuroimaging

Psychophysical stress disturbs expression of mitochondrial biogenesis markers in hypothalamus and adenohypophysis

Summary. Although psychophysical stress is widespread in human society and a major contributor to a range of pathological conditions, it is not known if this form of stress regulates mitochondrial biogenesis in the hypothalamus or adenohypophysis, the main organs involved in compensatory specifc response of the organism to stress (so called “fght or flight” response). Accordingly, this study was designed to evaluate the effects of acute and repeated psychophysical stress on a profle of mitochondrial biogenesis markers in the hypothalamus and adenohypophysis. Rats were either lef undisturbed (freely moving, control group) or exposed to psychophysical stress by immobilization (IMO) for 2 h (acute, 1xIMO) or 2 h daily for 2 (repeated, 2xIMO) or 10 consecutive days (repeated, 10xIMO). Result suggest that all types of immobilization stress signifcantly increase expression of hypothalamic NRF1 (nuclear respiratory factor 1; acts on the genes for subunits of the OXPHOS encoded by the nuclear genome) as well as its downstream target TFAM (mitochondrial transcription factor A), the essential ubiquitous factors for mtDNA replication and expression. In the same samples, TFB1M (markedly enhance mtDNA transcription) significantly decreased, while the level of COX4 (mitochondrial complex IV cytochrome C oxidase) protein was reduced only in hypothalamuses isolated from repeatedly stressed rats. Independently of the type of stress, the level of PGC1 protein, the master regulator of mitochondrial biogenesis involved in transcriptional control of all processes related to mitochondrial homeostasis and integrator of environmental signals, remained unchanged. In adenohypophyses of the same animals, 10xIMO signifcantly increased expression of adenohypophyseal PGC1 as well as its downstream target TFB1M, while NRF1 and TFAM remained unchanged. Similarly to hypothalamuses, the level of COX4 protein was reduced in adenohypophyses isolated from repeatedly stressed rats. Our results provide new molecular insights into the relationship between stress and hypothalamo-adenohypophyseal axis, as well as mitochondrial biology

Multielectron spectroscopy: Auger decays of the argon 2p hole

All the different Auger decay paths of Argon 2p holes have been characterized using a time of flight spectrometer of the magnetic bottle type. All electrons (the photoelectron and up to three Auger electrons) are detected in coincidence and resolved in energy. Double Auger decay is shown to proceed either through a direct process or by intense cascade paths, implying highly excited autoionizing Ar2+ states, which are identified as Ar2+ 3s−2 correlation satellites. Triple Auger decay is also observed and estimated to account for 0.2% only of all Auger decay