Task-dependent evolution of modularity in neural networks

There exist many ideas and assumptions about the development and meaning of modularity in biological and technical neural systems. We empirically study the evolution of connectionist models in the context of modular problems. For this purpose, we define quantitative measures for the degree of modularity and monitor them during evolutionary processes under different constraints. It turns out that the modularity of the problem is reflected by the architecture of adapted systems, although learning can counterbalance some imperfection of the architecture. The demand for fast learning systems increases the selective pressure towards modularity.     

Evidence that leptin contributes to intestinal cholesterol absorption in obese (ob/ob) mice and wild-type mice

In the present study, the effect of leptin on intestinal cholesterol absorption was investigated in C57 BL/6 OlaHsd Lep^ob/Lep^ob obese (ob/ob) mice and lean C57 BL/6 (wild-type) mice. Animals were treated either with or without recombinant leptin for 2 wk. Cholesterol absorption was measured by the constant isotope feeding method and indirectly by the ratio of campesterol to cholesterol in serum. In ob/ob mice, cholesterol absorption was significantly higher compared to wild-type mice [83.4±2.3% (SD) vs. 77.6±1.5%, P<0.01]. Treatment with leptin significantly reduced cholesterol absorption in both ob/ob and wild-type mice by 8.5 (P<0.001) and 5.2% (P<0.05), respectively. Serum concentrations of campesterol and the ratio of campesterol to cholesterol in ob/ob mice were significantly higher compared to wild-type mice (2.2±0.3 mg/dL vs. 1.2±0.3 mg/dL, P<0.001; and 36.8±2.8 μg/mg vs. 28.0±3.3 μg/mg, P<0.001). After treatment of ob/ob mice with leptin, concentrations of campesterol and its ratio to cholesterol were significantly lower (2.2±0.3 mg/dL vs. 1.0±0.2 μg/mg, P<0.001; and 36.8±2.8 μg/mg vs. 13.2±2.2 μg/mg, P<0.001, respectively). In wild-type mice, the ratio of campesterol to cholesterol in serum was also significantly lower after treatment with leptin (28.0±3.3 μg/mg vs. 22.6±5.0 μg/mg, P<0.05). A significant positive correlation (r=0.701, P<0.01) between cholesterol absorption and the ratio of campesterol to cholesterol, in serum was found. It is concluded that leptin contributes to intestinal cholesterol absorption in ob/ob mice and lean wild-type mice.     

Effects of phenotypic redundancy in structure optimization

Concepts from graph theory and molecular evolution are proposed for analyzing the redundancy in the genotype-phenotype mapping in structure optimization stemming from graph isomorphism. Evolutionary topology optimization of neural networks serves as an example. By means of analytical and random-walk methods, it is shown that rare and frequent structures influence the search process: operators that are unbiased in genotype space may have a remarkable bias in phenotype space. In particular, if the desired structures are rare, the probability that an evolutionary algorithm evolves them may decrease. This is verified experimentally by comparing evolutionary structure optimization algorithms with and without search operators that take the redundancy of phenotypes into account. Further, it is shown how different encodings and restrictions on the search space lead to qualitatively different distributions of rare and frequent structures     

电镀及表面处理工业的目标、趋势及远景

可持续发展、产品稳定性及各种新的环保法律法规使电镀业面临新的挑战.本文介绍了几种新的环保技术--包括生物除油剂、电解除油自动添加系统、先进的离子交换系统及长效珍珠镍工艺等--的应用状况,探讨了电镀行业可持续发展策略.指出建立技术中心、开发新技术、发展绿色工艺是电镀业未来的发展方向.     

Registration of CT and Intraoperative 3-D Ultrasound Images of the Spine Using Evolutionary and Gradient-Based Methods

A system for the registration of computed tomography and 3-D intraoperative ultrasound images is presented. Three gradient-based methods and one evolutionary algorithm are compared with regard to their suitability to solve this image registration problem. The system has been developed for pedicle screw insertion during spinal surgery. With clinical preoperative and intraoperative data, it is demonstrated that precise registration is possible within a realistic range of initial misalignment. Significant differences can be observed between the optimization methods. The covariance matrix adaptation evolution strategy shows the best overall performance, only four of 12 000 registration trials with patient data failed to register correctly.     

The chaining syllogism in fuzzy logic

We analyze the validity of the chaining syllogism in fuzzy systems, i.e., whether two fuzzy rules IF F, THEN G, and IF G, THEN H imply the rule IF F, THEN H. Conditions are given under which this basic deduction scheme holds. "If A is predicated of all B, and B of all C, A must necessarily be predicated of all C." ;-The chaining syllogism according to Aristotle's Prior Analytics.     

Fiber-Based Broadband-Access Deployment in the United States

After more than 20 years of research and development, a combination of technological, regulatory, and competitive forces are finally bringing fiber-based broadband access to commercial fruition. The three main approaches-hybrid fiber coax, fiber to the cabinet, and fiber to the home-are each vying for dominance in the industry, and each has significant future potential to grow customers and increase bandwidth and associated-service offerings. Further technical advances and cost reductions will be adopted, eventually bringing performance levels and bandwidth to gigabits-per-second rates when user demand warrants while keeping service costs affordable     

Chronic effects of a nonpeptide corticotropin-releasing hormone type I receptor antagonist on pituitary-adrenal function, body weight, and metabolic regulation

CRH, the principal regulator of the hypothalamic-pituitary-adrenal axis and modulator of autonomic nervous system activity, also participates in the regulation of appetite and energy expenditure. Antalarmin, a pyrrolopyrimidine compound, antagonizes CRH type 1 receptor-mediated effects of CRH, including pituitary ACTH release, stress behaviors, and acute inflammation. We administered antalarmin chronically to evaluate its effects on hypothalamic-pituitary-adrenal axis function and metabolic status. Adult male rats were treated twice daily with 20 mg/kg of i.p. antalarmin or placebo over 11 days. The animals were weighed; plasma ACTH, corticosterone, leptin, and blood glucose levels were determined; and morphometric analyses were performed to determine adrenal size and structure, including sizing, histochemistry, immunohistochemistry, and electron microscopy. Leptin messenger RNA expression in peripheral fat was analyzed by Northern blot. Antalarmin decreased plasma ACTH (mean +/- SD, 2.62 +/- 0.063 pg/ml) and corticosterone concentrations (10.21 +/- 1.80 microg/dl) compared with those in vehicle-treated rats [respectively, 5.3 +/- 2.0 (P < 0.05) and 57.02 +/- 8.86 (P < 0.01)]. Antalarmin had no significant effect on body weight, plasma leptin, or blood glucose concentrations or fat cell leptin messenger RNA levels. The width of the adrenal cortex of animals treated with antalarmin was reduced by 31% compared with that in controls without atrophy of the gland. On the ultrastructural level, adrenocortical cells were in a hypofunctional state characterized by reduced vascularization, increased content of lipid droplets, and tubulovesicular mitochondria with fewer inner membranes. The apoptotic rate was increased in the outer zona fasciculata of animals treated with the antagonist (26.6 +/- 3.58%) compared with that in placebo-treated controls (6.8 +/- 0.91%). We conclude that chronic administration of antalarmin does not affect body weight, carbohydrate metabolism, or leptin expression, whereas it reduces adrenocortical function mildly, without anatomical, clinical, or biochemical evidence of causing adrenal atrophy. These results are promising for future uses of such an antagonist in the clinic.