An information-based neural approach to generic constraint satisfaction

A novel artificial neural network heuristic (INN) for general constraint satisfaction problems is presented, extending a recently suggested method restricted to boolean variables. In contrast to conventional ANN methods, it employs a particular type of non-polynomial cost function, based on the information balance between variables and constraints in a mean-field setting. Implemented as an annealing algorithm, the method is numerically explored on a testbed of Graph Coloring problems. The performance is comparable to that of dedicated heuristics, and clearly superior to that of conventional mean-field annealing.     

A simple parametric study of ventilation

A simple study is described which demonstrates the relative importance of the various parameters which determine ventilation. The graphs presented can be used directly to estimate natural and mechanical ventilation rates under a wide variety of simple conditions. By adopting a non-dimensional approach which introduces the concept of the whole-house leakage Reynolds number, the basis is laid for a more general means of estimating ventilation from graphical data sheets.     

Sputtering and Ion-Source Technology

Sputtering is dependent on a number of projectile and target parameters. It is shown that the dependence of the sputtering yield on projectile energy, angle of incidence and atomic number is well understood. Also, the dependence on the bulk properties of the target is described reasonably well by theory, while the dependence on the actual surface topography of the target is difficult to quantify. Positive-ion sources mainly depend on the number of atoms sputtered per incoming ion (sputtering yield), while also energy- and angular-distributions of the sputtered material are of primary importance for negative-ion sources. These distributions are reasonably well known and allow a direct calculation of the emittance of some negative-ion sources.     

Single crystal growth of the transition metal monoxides by skull melting

A modified Bridgman technique by crucibleless skull melting has been applied to the growth of equiaxed, cmsized Mn_1?xO, Co_1?xO and Fe_1?x single crystals in f_o2 buffered atmospheres. The use of COCO₂ gaseous mixtures, suitable for growth and subsolidus annealing, has been investigated in order to optimize homogeneity, as indicated by X-ray diffraction and polarized reflected light microscopic characterization.     

Interaction of soluble C3 fragments with guinea pig lymphocytes. Comparison of effects of C3a, C3b, C3c, and C3d on lymphokine production and lymphocyte proliferation

C3a, C3b, C3c, and C3d were generated from purified guinea pig C3 by trypsin treatment. These fragments were characterized immunochemically and functionally by rosette inhibition. C3b is capable of binding to both C3b and C3d receptors on lymphocytes whereas C3d binds only to C3D receptors. C3b stimulates guinea pig spleen cells to elaborate a macrophage chemotactic factor which is similar in m.w. to that generated in response to PHA or LPS and is antigenically unrelated to C3 or C5. In contrast, neither C3a, C3c, or C3d stimulate guinea pig lymphocytes. Neither C3 nor any of its major fragments induce cellular proliferation. These data are compatible with the hypothesis that C3b triggers spleen cells to release a macrophage chemotactic factor by cross-linking C3b and C3d receptors.     

Incremental-redundancy transmission for meteor-burst communications

The performance of type-II hybrid automatic repeat request (ARQ) is compared to that of fixed-rate type-I hybrid ARQ for meteor-burst communications. Maximum throughput is obtained for meteor-burst communications by using a transmission scheme for which the information rate of the code, varies in response to the fluctuations in the power received from a meteor trail. For type-II hybrid ARQ, a variation in the code rate is inherent in the coding scheme. On the first transmission that is made for a data block, a code of relatively high rate is used, but if an additional transmission is required, only redundant symbols are sent, and this reduces the overall rate of the code. The performance measure is the throughput per trail, which is defined as the expected number of successfully received information bits for a given meteor trail. The authors also develop an approximation for the average value of the throughput, averaged over the parameters of the meteor trail. Numerical results for Reed-Solomon codes are included to illustrate the relative performance of the various schemes. It is shown that the throughput is larger for type-II hybrid ARQ than for either fixed-rate type-I hybrid ARQ or ARQ without forward-error-correction     

Leaf-tying by tortricid larvae as an adaptation for feeding on phototoxicHypericum perforatum

Hypericin, an anthrone dimer inHypericum perforatum (Guttiferae), is shown for the first time to be phototoxic to generalist lepidopteran larvae; survivorship was reduced and development prolonged forHeliothis zea (Noctuidae) andPlatynota flavedana (Tortricidae) that consumed hypericin diets in the presence of light. Survivorship for both species is enhanced when photoactivating wavelengths are excluded by filters. In natureP. flavedana successfully survives onH. perforatum by tying together leaves and feeding inside the ties. Shielded from light, the larvae are protected by their mode of feeding from phototoxic compounds.     

Analysis of sodium isethionate in soap and lye process streams by suppressed ion chromatography

Suppressed ion chromatography has been used to determine sodium isethionate in various soap production process streams at concentrations of 0.1–1.0%. The method was validated by spiking placebo soap and lye process stream samples. Overall recoveries in soap were 98.5 ± 2.3% (n=24). Recoveries in lye were 98.4 ± 2.8% (n=24).