Imaging-documented repeated intratumoral hemorrhage in vestibular schwannoma: a case report

Intratumoral hemorrhage in vestibular schwannomas is rare. Symptoms often have an acute onset and include headache, nausea, vomiting, vertigo, and depressed consciousness. Intratumoral hemorrhage is probably caused by vascular fragility associated with tumor characteristics and growth. With hemorrhage in VS being rare, repeated hemorrhage has only been reported twice, and on clinical grounds only. The present report details the case of acute neurological deterioration in a patient with repeated intratumoral hemorrhage inside a vestibular schwannoma with computed tomography and magnetic resonance imaging confirmation. To our knowledge, repeated hemorrhage in vestibular schwannoma with radiological confirmation has not been reported before

A Hebbian approach to complex network generation

Through a redefinition of patterns in an Hopfield-like model, we introduce and develop an approach to model discrete systems made up of many, interacting components with inner degrees of freedom. Our approach clarifies the intrinsic connection between the kind of interactions among components and the emergent topology describing the system itself; also, it allows to effectively address the statistical mechanics on the resulting networks. Indeed, a wide class of analytically treatable, weighted random graphs with a tunable level of correlation can be recovered and controlled. We especially focus on the case of imitative couplings among components endowed with similar patterns (i.e. attributes), which, as we show, naturally and without any a-priori assumption, gives rise to small-world effects. We also solve the thermodynamics (at a replica symmetric level) by extending the double stochastic stability technique: free energy, self consistency relations and fluctuation analysis for a picture of criticality are obtained

The neurobiological characterization of distinct cognitive subtypes in early-phase schizophrenia-spectrum disorders

INTRODUCTION: Cognitive deficits are present in some, but not all patients with schizophrenia-spectrum disorders (SSD). We and others have demonstrated three cognitive clusters: cognitively intact patients, patients with deficits in a few domains and those with global cognitive deficits. This study aimed to identify cognitive subtypes of early-phase SSD with matched controls as a reference group, and evaluated cognitive subgroups regarding clinical and brain volumetric measures. METHODS: Eighty-six early-phase SSD patients were included. Hierarchical cluster analysis was conducted using global performance on the Brief Assessment of Cognition in Schizophrenia (BACS). Cognitive subgroups were subsequently related to clinical and brain volumetric measures (cortical, subcortical and cortical thickness) using ANCOVA. RESULTS: Three distinct cognitive clusters emerged: relative to controls we found one cluster of patients with preserved cognition (n = 25), one moderately impaired cluster (n = 38) and one severely impaired cluster (n = 23). Cognitive subgroups were characterized by differences in volume of the left postcentral gyrus, left middle caudal frontal gyrus and left insula, while differences in cortical thickness were predominantly found in fronto-parietal regions. No differences were demonstrated in subcortical brain volume. DISCUSSION: Current results replicate the existence of three distinct cognitive subgroups including one relatively large group with preserved cognitive function. Cognitive subgroups were characterized by differences in cortical regional brain volume and cortical thickness, suggesting associations with cortical, but not subcortical development and cognitive functioning such as attention, executive functions and speed of processing

Impact of school lunch type on nutritional quality of English children's diets.

OBJECTIVE: Nutrient and food standards exist for school lunches in English primary schools although packed lunches brought from home are not regulated. The aim of the present study was to determine nutritional and dietary differences by lunch type. DESIGN: A cross-sectional survey was carried out in 2007 assessing diet using the Child and Diet Evaluation Tool (CADET), a validated 24 h estimated food diary. The data were analysed to determine nutritional and dietary intakes over the whole day by school meal type: school meals and packed lunches. SETTING: Fifty-four primary schools across England. SUBJECTS: Children (n 2709) aged 6-8 years. RESULTS: Children having a packed lunch consumed on average 11·0 g more total sugars (95 % CI 6·6, 15·3 g) and 101 mg more Na (95 % CI 29, 173 mg) over the whole day. Conversely, children having a school meal consumed, on average, 4·0 g more protein (95 % CI 2·3, 5·7 g), 0·9 g more fibre (NSP; 95 % CI 0·5, 1·3 g) and 0·4 mg more Zn (95 % CI 0·1, 0·6 mg). There was no difference in daily energy intake by lunch type. Children having a packed lunch were more likely to consume snacks and sweetened drinks; while children having a school meal were more likely to consume different types of vegetables and drink water over the whole day. CONCLUSIONS: Compared with children having a school meal, children taking a packed lunch to school consumed a lower-quality diet over the whole day, including higher levels of sugar and Na and fewer vegetables. These findings support the introduction of policies that increase school meal uptake

Entanglement of Dirac fields in non-inertial frames

We analyze the entanglement between two modes of a free Dirac field as seen by two relatively accelerated parties. The entanglement is degraded by the Unruh effect and asymptotically reaches a non-vanishing minimum value in the infinite acceleration limit. This means that the state always remains entangled to a degree and can be used in quantum information tasks, such as teleportation, between parties in relative uniform acceleration. We analyze our results from the point of view afforded by the phenomenon of entanglement sharing and in terms of recent results in the area of multi-qubit complementarity.Comment: 15 pages, with 8 figures (Mar 2006); accepted to Physical Review A, July 2006 - slightly revise

On the zig-zag pilot-wave approach for fermions

We consider a pilot-wave approach for the Dirac theory that was recently proposed by Colin and Wiseman. In this approach, the particles perform a zig-zag motion, due to stochastic jumps of their velocity. We respectively discuss the one-particle theory, the many-particle theory and possible extensions to quantum field theory. We also discuss the non-relativistic limit of the one-particle theory. For a single particle, the motion is always luminal, a feature that persists in the non-relativistic limit. For more than one particle the motion is in general subluminal.Comment: 23 pages, no figures, LaTe

Compton and double Compton scattering processes at colliding electron-photon beams

Radiative corrections (RC) to the Compton scattering cross section are calculated in the leading and next-to leading logarithmic approximation to the case of colliding high energy photon-electron beams. RC to the double Compton scattering cross section in the same experimental set-up are calculated in the leading logarithmic approximation. We consider the case when no pairs are created in the final state. We show that the differential cross section can be written in the form of the Drell-Yan process cross-section. Numerical values of the $K$-factor and the leading order distribution on the scattered electron energy fraction and scattering angle are presented

Probability in Orthodox Quantum Mechanics: Probability as a Postulate Versus Probability as an Emergent Phenomenon

The role of probability in quantum mechanics is reviewed, with a discussion of the ``orthodox'' versus the statistical interpretive frameworks, and of a number of related issues. After a brief summary of sources of unease with quantum mechanics, a survey is given of attempts either to give a new interpretive framework assuming quantum mechanics is exact, or to modify quantum mechanics assuming it is a very accurate approximation to a more fundamental theory. This survey focuses particularly on the issues of whether probabilities in quantum mechanics are postulated or emergent.Comment: Latex; Submitted to the Proceedings of the Ischia Conference on ``Chance in Physics: Foundations and Perspectives'

Gauge theories as a geometrical issue of a Kaluza-Klein framework

We present a geometrical unification theory in a Kaluza-Klein approach that achieve the geometrization of a generic gauge theory bosonic component. We show how it is possible to derive the gauge charge conservation from the invariance of the model under extra-dimensional translations and to geometrize gauge connections for spinors, thus we can introduce the matter just by free spinorial fields. Then, we present the applications to i)a pentadimensional manifold $V^{4}\otimes S^{1}$, so reproducing the original Kaluza-Klein theory, unless some extensions related to the rule of the scalar field contained in the metric and the introduction of matter by spinors with a phase dependence from the fifth coordinate, ii)a seven-dimensional manifold $V^{4}\otimes S^{1}\otimes S^{2}$, in which we geometrize the electro-weak model by introducing two spinors for any leptonic family and quark generation and a scalar field with two components with opposite hypercharge, responsible of spontaneous symmetry breaking.Comment: 37 pages, no figure

Designing Contextualized Learning

Specht, M. (2008). Designing Contextualized Learning. In H. H. Adelsberger, Kinshuk, J. M. Pawlowski & D. Sampson (Eds.), Handbook on Information Technologies for Education and Training (2th ed., pp. 101-111). Springer, Berlin Heidelberg 2008: International Handbook on Information Systems Series.Contextualized and ubiquitous learning are relatively new research areas that combine the latest developments in ubiquitous and context aware computing with pedagogical approaches relevant to structure more situated and context aware learning support. Searching for different backgrounds of mobile and contextualized learning authors have identified the relations between existing educational paradigms and new classes of mobile appli- cations for education (Naismith, Lonsdale, Vavoula, & Sharples, 2004). Furthermore best practices of mobile learning applications have been iden- tified and discussed in focused workshops (Stone, Alsop, Briggs, & Tomp- sett, 2002; Tatar, Roschelle, Vahey, & Peunel, 2002). Especially in the area of educational field trips (Equator Project, 2003; RAFT, 2003) in the last years innovative approaches for intuitive usage of contextualized mo- bile interfaces have been developed. The following paper describes the motivation and background for con- textualizing learning and illustrates the implementation of a service based and flexible learning toolkit developed in the RAFT project for supporting contextualized collaborative learning support