Inference, inquiry, evidence censorship, and explanation inconnectionist expert systems

The combination of the techniques of expert systems and neural networks has the potential of producing more powerful systems, for example, expert systems able to learn from experience. In this paper, we address the combinatorial neural model (CNM), a kind of fuzzy neural network able to accommodate in a simple framework the highly desirable property of incremental learning, as well as the usual capabilities of expert systems. We show how an interval-based representation for membership grades makes CNM capable of reasoning with several types of uncertainty: vagueness, ignorance, and relevance commonly found in practical applications. In addition, we show how basic functions of expert systems such as inference, inquiry, censorship of input information, and explanation may be implemented. We also report experimental results of the application of CNM to the problem of deforestation monitoring of the Amazon region using satellite images     

An expert system with temporal reasoning for alarm processing inpower system control centers

The alarm lists presented to control center operators are usually difficult to interpret. The authors present an expert system that processes the alarm lists in Portuguese control centers. This system makes an intelligent synthesis of the available information and presents it in a flexible and structured way. It uses an original approach to deal with temporal reasoning and real-time constraints. The system incorporates an explanation module that enables its use as a tutor for novice operators     

Actions of cisplatin on the electrophysiological properties of cultured dorsal root ganglion neurones from neonatal rats

In this study we have employed the whole cell patch clamp technique to investigate the effects of an anti-cancer drug cisplatin on basic electrophysiological properties of cultured dorsal root ganglion neurones from neonatal rats. The results show that within the clinical concentration range, cisplatin (0.1 to 10 microM) caused a decrease in input conductance, and complex changes in resting membrane potential in these cultured sensory neurones. The dominant effects of cisplatin on input conductance may be due to inhibition of leak conductances. Transplatin (5 microM) was significantly less effective than cisplatin at reducing input conductance which suggests a degree of stereoselectivity. Cisplatin (1 to 5 microM) transiently increased excitability of the cultured neurones as reflected by a reduction in the threshold for activation of action potentials by 8 mV. The rise time, peak amplitude and duration of action potentials were not changed by acute application of 5 microM cisplatin. Long term treatment of neurones with cisplatin (5 microM), for up to 1 week reduced the viability of the cultures, and attenuated neurone excitability, although input conductance of the cells was significantly increased to 322 +/- 49 M omega (n = 9) compared with controls of 210 +/- 20 M omega (n = 30; P < 0.05). Acute and chronic treatment of cultured neurones with cisplatin therefore produced contrasting actions.     

Detection of anti-HIV-1 IgG antibodies in whole saliva by GACELISA and Western blot assays

The present study, based on 158 HIV seropositives and 167 HIV seronegatives, demonstrates that saliva collected with the Omni-SAL device and tested with GACELISA (an IgG antibody capture ELISA) is an effective non-invasive alternative to serum for anti-HIV IgG antibody screening. The study also shows that a conventional serum Western blot kit can be used, with slight modifications, for confirmatory testing of saliva specimens. Collecting saliva with the Omni-SAL device had a very good acceptance rate among Tanzanian subjects, and although this diagnostic method is not yet known by the general public, 65% of the study participants preferred to give saliva instead of blood for HIV testing.     

Multiple Testing Correction in Medical Image Analysis

We present a novel method for correcting the significance level of hypothesis testing that requires multiple comparisons. It is based on the spectral graph theory, in which the variables are seen as the vertices of a complete undirected graph and the correlation matrix as the adjacency matrix that weights its edges. The method increases the statistical power of the analysis by refuting the assumption of independence among variables, while keeping the probability of false positives low. By computing the eigenvalues of the correlation matrix, it is possible to obtain valuable information about the dependence levels among the variables of the problem, so that the effective number of independent variables can be estimated. The method is compared to other available models and its effectiveness illustrated in case studies involving high-dimensional sets of variables.     

注聚末期颗粒调剖技术应用效果分析

注聚末期如何突破现有的技术和工艺,提高聚合物的利用率,改善聚合物驱开发效果,是聚合物驱油田开发亟待解决的瓶颈问题.预交联颗粒调剖剂具有较好的体膨性能,调剖粒径、强度和膨胀倍数等可调,可有效地调整吸入剖面,改善聚合物驱开发效果,提高聚合物驱最终采收率.研究了注聚末期颗粒调剖技术的特点及选井选层方法,详细分析了萨北开发区注聚末期颗粒调剖后聚合物驱动态指标变化规律.     

养马岛大桥钢管拱肋支撑架的设计与施工

介绍了养马岛大桥钢管拱肋支撑架的设计与施工，从设计方案的比选、施工技术等方面进行了论述，指出该桥使用此种支架施工，保证了质量，降低了成本。     

Kinetic trapping of oxygen in cell respiration

Cell respiration in eukaryotes is catalysed by mitochondrial enzyme cytochrome c oxidase. In bacteria there are many variants of this enzyme, all of which have a binuclear haem iron-copper centre at which O2 reduction occurs, and a low-spin haem, which serves as the immediate electron donor to this centre. It is essential that the components of the cell respiratory system have a high affinity for oxygen because of the low concentration of dissolved O2 in the tissues; however, the binding of O2 to the respiratory haem-copper oxidases is very weak. This paradox has been attributed to kinetic trapping during fast reaction of O2 bound within the enzyme's binuclear haem iron-copper centre. Our earlier work indicated that electron transfer from the low-spin haem to the oxygen-bound nuclear centre may be necessary for such kinetic oxygen trapping. Here we show that specific decrease of the haem-haem electron transfer rate in the respiratory haem-copper oxidase from Escherichia coli leads to a corresponding decrease in the enzyme's operational steady-state affinity for O2. This demonstrates directly that fast electron transfer between the haem groups is a key process in achieving the high affinity for oxygen in cell respiration.     

Use of exercise technetium-99m sestamibi SPECT imaging to detect residual ischemia and for risk stratification after acute myocardial infarction

The clinical presentation, electrocardiographic findings, and technetium-99m sestamibi single-photon emission computed tomography (SPECT) imaging results of 134 consecutive patients who underwent nuclear exercise testing within 14 days of an acute myocardial infarction (AMI) were correlated with cardiac events over a 15 +/- 10-month follow-up. Whereas only 23 patients (17%) had chest pain and 31 (23%) had ischemic ST-segment depression during exercise, 94 (70%) had ischemia on SPECT (p < 0.001). On follow-up, 13 patients experienced a cardiac event: 7 were rehospitalized for unstable angina, 3 had recurrent AMI, and 3 died of cardiac causes. Ischemia on the sestamibi images identified 11 of these patients (85%), whereas chest pain identified only 3 (23%, p = 0.006), and electrocardiographic ischemia identified only 4 (31%, p = 0.017). The presence of either ischemia as seen on SPECT or defects in multiple vascular territories identified 12 patients (92%) with an event, including all who had cardiac death. By Cox regression analysis of clinical, stress, and image parameters, the number of ischemic defects on SPECT was the only significant correlate of a future event (chi-square = 4.62, p = 0.03), and patients with > or = 3 reversible sestamibi defects had an event rate of 38%. The extent of ischemia as seen on nuclear imaging remained a strong correlate (p = 0.008) of an event in the 54 patients (40%) who had received thrombolytic therapy. Thus, exercise technetium-99m sestamibi SPECT after AMI frequently reveals residual ischemia, and is better than clinical data, symptoms, and stress electrocardiographic data in identifying patients who will have a subsequent cardiac event.