On coherence, random-self-reducibility, and self-correction

We study three types of self‐reducibility that are motivated by the theory of program verification. A set A is random‐self‐reducible if one can determine whether an input x is in A by making random queries to an A‐oracle. The distribution of each query may depend only on the length of x. A set B is self‐correctable over a distribution if one can convert a program that is correct on most of the probability mass of to a probabilistic program that is correct everywhere. A set C is coherent if one can determine whether an input x is in C by asking questions to an oracle for C–{x}.?We first show that adaptive coherence is more powerful than nonadaptive coherence, even if the nonadaptive querier is nonuniform. Blum et al.(1993) showed that every random‐self‐reducible function is self‐correctable. It is unknown, however, whether self‐correctability implies random‐self‐reducibility. We show, assuming a reasonable complexity‐theoretic hypothesis, that certain hard, sparse, tally sets exist, and that there is a self‐correctable function which is not random‐self‐reducible. For easily samplable distributions, however, we show that constructing a self‐correctable function that is not random‐self‐reducible is as hard as proving that P is different from PP. Received: 14 June, 1996     

一种基于二叉树的Cache一致性目录方法

本文提出了一种高度并发的Ｃａｃｈｅ一致性方法，着重描述了它的并发性，并且通过和ＩＥＥＥＳＣＩ协议的性能比较，表明这种Ｃａｃｈｅ一致性方法具有较好的伸缩能力，适于Ｓ２ＭＰ结构。     

DSM系统中共享存储抽象机制的实现

虽然ＤＳＭ系统相互之间差异很大，但ＤＳＭ存在一个共同特征，即提供共享存储抽象机制。本文分析了ＤＳＭ系统共享存储抽象机制的实现，总结了各种不同的实现途径、实现细节及各自的优缺点，指出了ＤＳＭ发展的趋势及一些亟待解决的问题。     

Updating Situation Models.

The authors examined how situation models are updated during text comprehension. If comprehenders keep track of the evolving situation, they should update their models such that the most current information, the here and now, is more available than outdated information. Contrary to this updating hypothesis, E. J. O'Brien, M. L. Rizzella, J. E. Albrecht, and J. G. Halleran (1998) obtained results suggesting that outdated or incorrect information may still influence the comprehension process. The authors of the current study demonstrate that the nature of E. J. O'Brien et al.'s materials were the likely cause of this pattern of results. Hence, the current authors constructed materials that circumvent identified confounds and in a reading-time experiment obtained evidence supporting the here-and-now hypothesis. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Updating Situation Models: Reply to Zwaan and Madden (2004).

E. J. O'Brien, M. L. Rizzella, J. E. Albrecht, and J. G. Halleran (1998) demonstrated that, consistent with the memory-based text processing view, outdated or incorrect information can be reactivated through a passive resonance process. Once reactivated, this outdated information can still influence comprehension. R. A. Zwaan and C. J. Madden (2004) suggested that the O'Brien et al. findings resulted from problems with the materials used. The present authors show that the possible "problems" identified by Zwaan and Madden do not adequately explain the findings of O'Brien et al. and that Zwaan and Madden's Experiment 3 lacks sufficient control or power to support their alternative interpretation of O'Brien et al. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Research of Colossal Magnetoresistance in La0.67Ca0.33Mn1-xCrxO3 (0.00≤x≤0.15)

The extraordinary colossal magnetoresistance (CMR) behavior in was found that the substitution with Cr on Mn sites introduces an additional bump in zero-field resistivity. With increasing Cr content, this additional bump grows up drastically while the original resistivity peak associated with magnetic order transition diminishes gradually. Under the applied magnetic field, both bumps of resistivity are deeply compressed, which leads to the appearance of two peaks in CMR response. As a result, the temperature range of CMR response is significantly broadened, spanned from the lowest to near room temperature. These results suggest that Mn-site element substitution could be a potent way of tuning CMR response.     

Blood flow dynamics reflect degree of outflow tract banding in Hamburger–Hamilton stage 18 chicken embryos

Altered blood flow during embryonic development has been shown to cause cardiac defects; however, the mechanisms by which the resulting haemodynamic forces trigger heart malformation are unclear. This study used heart outflow tract banding to alter normal haemodynamics in a chick embryo model at HH18 and characterized the immediate blood flow response versus the degree of band tightness. Optical coherence tomography was used to acquire two-dimensional longitudinal structure and Doppler velocity images from control (n = 16) and banded (n = 25, 6–64% measured band tightness) embryos, from which structural and velocity data were extracted to estimate haemodynamic measures. Peak blood flow velocity and wall shear rate (WSR) initially increased linearly with band tightness (p < 0.01), but then velocity plateaued between 40% and 50% band tightness and started to decrease with constriction greater than 50%, whereas WSR continued to increase up to 60% constriction before it began decreasing with increased band tightness. Time of flow decreased with constriction greater than 20% (p < 0.01), while stroke volume in banded embryos remained comparable to control levels over the entire range of constriction (p > 0.1). The haemodynamic dependence on the degree of banding reveals immediate adaptations of the early embryonic cardiovascular system and could help elucidate a range of cardiac adaptations to gradually increased load.     

Determining elastic properties of skin by measuring surface waves from an impulse mechanical stimulus using phase-sensitive optical coherence tomography

The mechanical properties of skin are important tissue parameters that are useful for understanding skin patho-physiology, which can aid disease diagnosis and treatment. This paper presents an innovative method that employs phase-sensitive spectral-domain optical coherence tomography (PhS-OCT) to characterize the biomechanical properties of skin by measuring surface waves induced by short impulses from a home-made shaker. Experiments are carried out on single and double-layer agar–agar phantoms, of different concentrations and thickness, and on in vivo human skin, at the forearm and the palm. For each experiment, the surface wave phase-velocity dispersion curves were calculated, from which the elasticity of each layer of the sample was determined. It is demonstrated that the experimental results agree well with previous work. This study provides a novel combination of PhS-OCT technology with a simple and an inexpensive mechanical impulse surface wave stimulation that can be used to non-invasively evaluate the mechanical properties of skin in vivo, and may offer potential use in clinical situations.     

Theoretical Hypothesis of a Double Barrier Regarding the D-D Interaction in a Pd Lattice： A Possible Explanation of Cold Fusion Experiment Failures

During the past 15 years, disputable experimental evidence has built up for LERN （low energy nuclear reaction） phenomena in specialized heavy hydrogen systems. Actually, it can not be said that a new branch of science is beginning. In spite of experimental contributions, the real problem is that the theoretical statements of LERN are unknown. In this work, the authors analyze the deuteron-deuteron reactions within palladium lattice by means of the coherence theory of nuclear and condensed matter and, using this general theoretical framework accepted from ＂cold fusion scientists＂, it will be shown the low occurrence probability of fusion phenomena. In fact, in the coherence approach, the D-D potential exhibits double barrier features and, in this way, the D-D fusion is hampered.