Ethical issues related to the use of facilitated communication techniques with persons with autism.

Addresses the ethical issues concerning the benefits and the risks involved with the use of facilitated communication techniques (F/C), particularly with autistic clients. F/C involves the physical support of a client by a facilitator in order to enable the client to use equipment for the purposes of communication. Much controversy stems from the fact that the validity of messages communicated when using a facilitator remains to be established empirically. The principles of respect for the client's dignity, informed consent, confidentiality, responsible caring, and the issue of the risk of inadvertant misuse and misinterpretation are discussed from an ethical viewpoint. Well controlled research is recommended in order to further understand the processes involved in the widespread acceptance of this technique. (French abstract) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

零度附近蒸发剩余核的双鉴别系统

本文介绍了一套由静电偏转系统,飞行时间谱仪及ΔE-E望远镜所组成的用于重离子核反应零度附近蒸发剩余核的双鉴别和探测系统,其中,使用国产微通道板作为飞行时间谱仪的零时间探测器,时间分辨达200ps。系统用于在束测最,核电荷数分辨好于23,质量数分辨达45。     

Impurity effects in molybdenum silicide formation

The reaction between molybdenum thin films and single-crystal Si〈111〉 substrates was studied as a function of the concentrations of impurities (mainly oxygen) in the metal film. At a low oxygen concent (1–2 at.%), only the silicide phase MoSi₂ was observed, and a thickness proportional to the square root of time corresponding to an average activation energy of 3 eV in the temperature range 545–600 °C was found. During the formation of the silicide the oxygen originally present in the molybdenum films accumulates at the interface between the silicon and the MoSi₂.In contrast, a higher oxygen content (4–5 at.%) prevents the formation of any silicide phases in the above temperature range and leads to the formation of MoSi₂ and Mo₅Si₃ phases at temperatures near 800 °C. MoSi₂ was always observed at the inner interface with Mo₅Si₃ on the surface.The oxygen segregates from the silicides and accumulates at the Si-MoSi₂ and MoSi₂-Mo₅Si₃ interfaces to form a non-uniform layer of SiO_x(x ? 2).     

The Coulomb interaction in the generalized Hartree-Fock theory of superconductivity

The matrix self-energy equations of the generalized Hartree-Fock (GHF) theory of HTSC are reevaluated and rederived, while avoiding some shortcomings of the former derivation. The density of states is given for an interacted and renormalized electronic system. The self-energy equations are essentially different in several respects from the conventional Eliashberg equations. The matrix self-energy is analyzed with respect to its dependence on (p). It is found to depend one very weakly, which results in self-energy equations which depend on a single variable,, as in the conventional theory. However, it is found that the bare Coulomb interaction contributes extra terms to the pairing self-energy and to the renormalization function. In the simplified version of the equations, the effect of these two extra terms is incorporated as a single extra term of the renormalization function.     

Bayes-optimal chemotaxis

Chemotaxis plays a crucial role in many biological processes, including nervous system development. However, fundamental physical constraints limit the ability of a small sensing device such as a cell or growth cone to detect an external chemical gradient. One of these is the stochastic nature of receptor binding, leading to a constantly fluctuating binding pattern across the cell's array of receptors. This is analogous to the uncertainty in sensory information often encountered by the brain at the systems level. Here we derive analytically the Bayes-optimal strategy for combining information from a spatial array of receptors in both one and two dimensions to determine gradient direction. We also show how information from more than one receptor species can be optimally integrated, derive the gradient shapes that are optimal for guiding cells or growth cones over the longest possible distances, and illustrate that polarized cell behavior might arise as an adaptation to slowly varying environments. Together our results provide closed-form predictions for variations in chemotactic performance over a wide range of gradient conditions.     

Recurrent sampling models for the Helmholtz machine

Many recent analysis-by-synthesis density estimation models of cortical learning and processing have made the crucial simplifying assumption that units within a single layer are mutually independent given the states of units in the layer below or the layer above. In this article, we suggest using either a Markov random field or an alternative stochastic sampling architecture to capture explicitly particular forms of dependence within each layer. We develop the architectures in the context of real and binary Helmholtz machines. Recurrent sampling can be used to capture correlations within layers in the generative or the recognition models, and we also show how these can be combined.     

Control of Halogen Atom in Inorganic Metal-Halide Perovskites Enables Large Piezoelectricity for Electromechanical Energy Generation

Regulating the strain of inorganic perovskites has emerged as a critical approach to control their electronic and optical properties. Here, an alternative strategy to further control the piezoelectric properties by substituting the halogen atom (I/Br) in the CsPbX₃ perovskite (X = Cl, Br) structure is adopted. A series of piezoelectric materials with excellent piezoelectric coefficients (d₃₃) are unveiled. Iodine-incorporated CsPbBr₂I demonstrates the record intrinsic piezoelectric response (d₃₃ ≈47 pC N⁻¹) among all inorganic metal halide perovskites. This leads to an excellent electrical output power of ≈ 0.375 mW (24.8 µW cm⁻² N⁻¹) in the piezoelectric energy generator (PEG) which is higher than those of the pristine/mixed perovskite references with CsPbX₃ (X = I, Br, Cl). With its structural phase remaining unchanged, the strained CsPbBr₂I retains its superior piezoelectricity in both thin film and nanocrystal powder forms, further demonstrating its repeatability and versatility of applications. The origin of high piezoelectricity is found to be due to halogen-induced anisotropic lattice strain in the unit-cell along the c-axis, and octahedral distortion. This study reveals an avenue to design new piezoelectric materials by modifying their halide constituents and paves the way to design efficient PEGs for improved electromechanical energy conversion.     

Neurochemical findings in a perinatal sudanophilic leukodystrophy rich in steryl ester

Neurochemical and neuropathological studies have been made of a 10-day-old child who suffered from a sudanophilic leukodystrophy. The brain white matter contained abundant sudanophilic material. The patient's grey matter total cholesterol content was 30% higher than whole brain tissue derived from a comparable control. White matter cholesterol content was more than double the control value. Nearly 80% of the white matter cholesterol was esterified. Subcellular fractionation of the white matter resulted in a "floating fraction" rich in cholesteryl ester. The steryl ester fatty acid composition was not typical of control tissue or demyelinating tissue. Patient phospholipid fatty acid composition patterns differed from control, but white matter galactolipid fatty acid composition appeared normal. Cholesteryl ester hydrolase activity appeared normal. Myelin and myelin-like fractions, isolated from diseased and normal brain tissue, were of a primitive developing nature but appeared to be comparable. The findings indicate a neonatal sudanophilic leukodystrophy which doubtless began in prenatal life and which was rich in cholesteryl ester. The aetiology of the leukodystrophy is unknown.     

Tunneling measurements on crystalline and granular aluminum

Electron tunneling measurements have been carried out on granular and crystalline aluminum. The Eliashberg gap equation has been inverted and ² F and ^* are given. Some problems such as anomalous effects in the junction behavior, and deviation from the BCS density of states at the gap edge in the granular case, and the data at low energies are qualitatively discussed.This work was done at Tel Aviv University, Department of Physics and Astronomy.