Alzheimer's Disease (AD) is the most frequent form of degenerative dementia and its early diagnosis is essential for effective treatment. Functional imaging modalities including Single Photon Emission Computed Tomography (SPECT) are often used with such an aim. However, conventional evaluation of SPECT images relies on manual reorientation and visual evaluation of tomographic slices which is time consuming, subjective and therefore prone to error. Our aim is to show an automatic Computer-Aided Diagnosis (CAD) system for improving the early detection of the AD. For this purpose, affine invariant descriptors of 3D SPECT image can be useful. The method consists of four steps: evaluation of invariant descriptors obtained using spherical harmonic analysis, statistical testing of their significance, application of regularized binary index models, and model verification via leave-one-out cross-validation scheme. The second approach is based on Support Vector Machine (SVM) classifier and visualization with use of self-organizing maps. Our approaches were tested on SPECT data from 11 adult patients with definite Alzheimer's disease and 10 adult patients with Amyotrophic Lateral Sclerosis (ALS) who were used as controls. A significant difference between SPECT spherical cuts of AD group and ALS group was both visually and numerically evaluated.
Given a fixed dependency graph G that describes a Bayesian network of binary variables X1,…,Xn, our main result is a tight bound on the mutual information Ic(Y1,…,Yk)=∑kj=1H(Yj)/c−H(Y1,…,Yk) of an observed subset Y1,…,Yk of the variables X1,…,Xn. Our bound depends on certain quantities that can be computed from the connective structure of the nodes in G. Thus it allows to discriminate between different dependency graphs for a probability distribution, as we show from numerical experiments.
Recent studies have shown interest in the evolution to steady nonlinear pulsation in stellar models. The simplest description is nonresonant interaction between the fundamental and one of its overtones, if one is only interested in the behaviour of a few longlived modes. The generic forni of coupled-mode equations is not dependent upon a particular stellar model, although
the precise determination of the coupling constants for a given stellar model will ultimately be very involved. Qualitative
ideas about the eventual evolution of the mode energies give different scenarios, depending mainly on the nonlinear coupling
constants and the linear growth rates, if the latter are both positive. According to one scenario, a double-mode pulsator is possible. It is not necessary that all coupling constants be negative, if only the model is well behaved enough in excludinq unbounded solutions. With a linearly stable fundamental and a stable overtone another scenario shovys a further possibility for a double-mode pulsator, if one of the cross coupling constants is positive, so that the overtone nonlinearly grows before saturating. Such findings show the need for additional theoretical and numerical modelling and a cautious discussion thereof.
a1_Perennial organ functions of trees living in seasonal environments exhibit temporal changes that can be classified as long-term interannual changes and seasonal fluctuations within single years. However, few studies have separately quantified these changes from longitudinal measurement data or analyzed the relationships between them. We developed a hierarchical Bayesian statistical model consisting of three parts: a long-term interannual change expressed by consecutive annual linear trends, seasonal fluctuations with 26 values for two-week periods in a year, and a random effect for repeated measurements. The model can extract long-term interannual changes and seasonal fluctuations from longitudinal repeated measure data. The pattern of seasonal fluctuation, the amount of seasonal fluctuation, and the net annual change are expressed by the estimated model parameters. We applied our model to foliar chlorophyll (Chl) and nitrogen (N) content measured repeatedly on more than 1-year-old leaves of saplings in four evergreen broad-leaved tree species using nondestructive optical methods. The model successfully explained large variations in the Chl and N content. In general, seasonal fluctuations corresponded to the phenology of current-year leaves; Chl and N tended to decrease from the opening to maturation of new leaves and increased during the rest period. The magnitude of the decrease in the Chl and N content in the growth period of current-year leaves (Δγ) did not decrease noticeably as leaves aged. For the Chl content, Δγ was positively correlated with the maximum value before leaf opening across species. For the N content, Δγ and the maximum value before leaf opening were not clearly correlated across species, but were positively correlated within some species., a2_A model parameter for annual linear trends in Chl and N varied from positive (indicating increasing trends) to negative values (indicating decrease) depending on species and leaf age in years., D. Mizusaki, K. Umeki, T. Honjo., and Obsahuje seznam literatury
Článek se zabývá disertací Nielse Bohra, kterou obhájil roku 1911. V první části je nastíněn vývoj Bohrovy disertační práce a jeho snahy práci přeložit do angličtiny. Dále Bohrův pobyt v Cambridgi u J. J. Thomsona a důvody, proč se nakonec rozhodl strávit zbytek svého zahraničního studijního pobytu v Manchesteru u E. Rutherforda. Druhá část příspěvku shrnuje historii vývoje elektronové teorie kovů. Nakonec jsou uvedeny závěry, ke kterým Bohr došel a ze kterých můžeme vyzdvihnout ten, že klasická mechanika je pro objekty na atomární úrovni nedostatečná., The article deals with Niels Bohr‘s dissertation defended in 1911. The first part of the article outlines the development of Bohr‘s dissertation and his strong efforts to translate the work into English. It also depicts Bohr‘s stay in Cambridge with J. J. Thomson and the reasons why he decided to spend the rest of his study abroad in Manchester with E. Rutherford. The second part describes the development of the electron theory of metals. It also summarizes conclusions of Bohr‘s dissertation from which we can highlight that classical mechanics is ineffective for objects at the atomic level., Kateřina Šraitrová., and Obsahuje seznam literatury
Let $G$ be a locally compact group and let $1 \le p < \infty.$ Recently, Chen et al. characterized hypercyclic, supercyclic and chaotic weighted translations on locally compact groups and their homogeneous spaces. There has been an increasing interest in studying the disjoint hypercyclicity acting on various spaces of holomorphic functions. In this note, we will study disjoint hypercyclic and disjoint supercyclic powers of weighted translation operators on the Lebesgue space $L^p(G)$ in terms of the weights. Sufficient and necessary conditions for disjoint hypercyclic and disjoint supercyclic powers of weighted translations generated by aperiodic elements on groups will be given., Liang Zhang, Hui-Qiang Lu, Xiao-Mei Fu, Ze-Hua Zhou., and Obsahuje bibliografické odkazy