Darker eumelanic barn owls better withstand food depletion through resistance to food deprivation and lower appetite.

The intensity of selection exerted on ornaments typically varies between environments. Reaction norms may help to identify the conditions under which ornamented individuals have a selective advantage over drab conspecifics. It has been recently hypothesized that in vertebrates eumelanin-based coloration reflects the ability to regulate the balance between energy intake and expenditure. We tested two predictions of this hypothesis in barn owl nestlings, namely that darker eumelanic individuals have a lower appetite and lose less weight when food-deprived. We found that individuals fed ad libitum during 24 h consumed less food when their plumage was marked with larger black spots. When food-deprived for 24 h nestlings displaying larger black spots lost less weight. Thus, in the barn owl the degree of eumelanin-based coloration reflects the ability to withstand periods of food depletion through lower appetite and resistance to food restriction. Eumelanic coloration may therefore be associated with adaptations to environments where the risk of food depletion is high

Personalization of supermarket product recommendations

Abstract. We describe a personalized recommender system designed to suggest new products to supermarket shoppers. The recommender functions in a pervasive computing environment, namely, a remote shopping system in which supermarket customers use Personal Digital Assistants (PDAs) to compose and transmit their orders to the store, which assembles them for subsequent pickup. The recommender is meant to provide an alternative source of new ideas for customers who now visit the store less frequently. Recommendations are generated by matching products to customers based on the expected appeal of the product and the previous spending of the customer. Associations mining in the product domain is used to determine relationships among product classes for use in characterizing the appeal of individual products. Clustering in the customer domain is used to identify groups of shoppers with similar spending histories. Cluster-specific lists of popular products are then used as input to the matching process. The recommender is currently being used in a pilot program with several hundred customers. Analysis of results to date have shown a 1.8 % boost in program revenue as a result of purchases made directly from the list of recommended products. A substantial fraction of the accepted recommendations are from product classes new to the customer, indicating a degree of willingness to expand beyond present purchase patterns in response to reasonable suggestions

Sequential and Parallel Branch-and-Bound Search Under Limited-Memory Constraints

Branch-and-bound (B&B) best-first search (BFS) is a widely applicable method that requires the least number of node expansions to obtain optimal solutions to combinatorial optimization problems (COPs). However, for many problems of interest, its memory requirements are enormous and can far exceed the available memory capacity on most systems. To circumvent this problem, a number of limited-memory search methods have been proposed that are either based purely on depth-first search (DFS) or combine BFS with DFS. We survey and compare previous sequential and parallel limited-memory search methods, and discuss their suitability for solving different types of COPs. We also propose a new limited-memory search method, iterative extrapolated-cost bounded search (IECBS), that performs a sequence of cost-bounded depth-first searches from the root node of the search space. In this method, cost bounds for successive iterations are set to an estimated optimal-solution cost obtained by ext..

Effect of carboxymethyl cellulose concentration on physical properties of biodegradable cassava starch-based films

<p>Abstract</p> <p>Background</p> <p>Cassava starch, the economically important agricultural commodity in Thailand, can readily be cast into films. However, the cassava starch film is brittle and weak, leading to inadequate mechanical properties. The properties of starch film can be improved by adding plasticizers and blending with the other biopolymers.</p> <p>Results</p> <p>Cassava starch (5%w/v) based films plasticized with glycerol (30 g/100 g starch) were characterized with respect to the effect of carboxymethyl cellulose (CMC) concentrations (0, 10, 20, 30 and 40%w/w total solid) and relative humidity (34 and 54%RH) on the mechanical properties of the films. Additionally, intermolecular interactions were determined by Fourier transform infrared spectroscopy (FT-IR), melting temperature by differential scanning calorimetry (DSC), and morphology by scanning electron microscopy (SEM). Water solubility of the films was also determined. Increasing concentration of CMC increased tensile strength, reduced elongation at break, and decreased water solubility of the blended films. FT-IR spectra indicated intermolecular interactions between cassava starch and CMC in blended films by shifting of carboxyl (C = O) and OH groups. DSC thermograms and SEM micrographs confirmed homogeneity of cassava starch-CMC films.</p> <p>Conclusion</p> <p>The addition of CMC to the cassava starch films increased tensile strength and reduced elongation at break of the blended films. This was ascribed to the good interaction between cassava starch and CMC. Cassava starch-CMC composite films have the potential to replace conventional packaging, and the films developed in this work are suggested to be suitable for low moisture food and pharmaceutical products.</p