Hybridizing discrete- and continuous-time models for batch sizing and scheduling problems

This paper proposes a new hybrid technique called “partial parameter uniformization” (hereafter PPU). The technique simplifies problems by ignoring the different values that certain problem parameters can take, which may facilitate the solution of some hard combinatorial optimization problems. PPU is applied to complex batch sizing and scheduling problems. Some information can be obtained from a discrete-time model in which job durations have been made uniform. This information is then exploited by a more detailed continuous-time model to generate feasible solutions and further improve these solutions. Good, or optimal solutions to the Westenberger and Kallrath Benchmark problems have been obtained in this way, at relatively low computational cost, as have solutions to the newer problems of Blömer and Günther.     

Synthesis and characterization of amino-functional, blue light-emitting copolymers and their composites with CdTe nanocrystals

Random side-chain functionalized copolymers were synthesized, utilizing a facile Yamamoto protocol by applying 2,7-dibromo-9,9-bis(6-bromohexyl)-9H-fluorene, (E)-1,2-bis(4-bromophenyl)ethene, 2,7-dibromo-9,9-dioctyl-9H-fluorene as comonomers. The precursor copolymers were post-functionalized utilizing di-n-propylamine and the resulting target copolymers were fully characterized. The optical classification parameters have been determined in solutions and in thin films as well. The copolymers revealed blue light emission, wide optical bandgaps Eg_opt of at least 2.84 eV and remarkable quantum yields up to 0.78 in chloroform solutions. The amino-functional copolymers allowed tying semiconductor CdTe nanocrystals.     

Welfare,performance and meat quality of fattening pigs in alternative housing and management systems: a review

Conventional husbandry systems for pork production are scrutinized by members of the general public as well as the scientific community. As a response, alternative forms of pig production, such as outdoor housing, organic farming and environmental enrichment are gaining interest. The question arises whether these production systems are indeed able to improve the welfare and health status of the animals, and whether these production systems alter production characteristics and meat or carcass traits. Measures of poor welfare have been described, but evaluating overall welfare is difficult. Certain parameters of alternative housing will improve welfare in some ways but, simultaneously, other welfare problems are inflated, and the weighting of each of these problems is very subjective. Alternative housing systems allow pigs to display species‐specific behaviour and decrease the occurrence of abnormal behaviours by acting on several parameters: indoor versus outdoor housing, floor space/density, floor type, and provision of bedding or other types of environmental enrichment. Evaluating alternative housing systems should be done by looking at all the welfare‐improving factors and the cost of alleviating welfare‐decreasing problems in a given production system. Data in the literature on growth, meat and carcass traits in alternative production systems, are inconsistent, indicating that other factors can play an important role. However, as equal, or in some cases even better, performance can be attained in certain production systems that meet concerns of animal welfare scientists and members of the general public, alternative production forms may be considered preferable. Copyright © 2005 Society of Chemical Industry     

The importance of callous–unemotional traits for extending the concept of psychopathy to children.

This study focused on the use of callous–unemotional (CU) traits to identify a subgroup of children with both attention deficit/hyperactivity disorder (ADHD) and a conduct problem diagnosis (oppositional defiant disorder [ODD] or conduct disorder [CD]) who show characteristics similar to adults with psychopathy. In a clinic-referred sample of children aged 6 to 13 years (N?=?154), those with diagnoses of both ADHD and ODD/CD were divided on the basis of teacher ratings of CU traits. Children high on these traits showed features typically associated with psychopathy, such as a lack of fearfulness and a reward-dominant response style. Furthermore, children with CU traits seemed less distressed by their behavior problems. These findings are consistent with research on adults showing that impulsivity and antisocial behavior alone are insufficient to document persons who fit the construct of psychopathy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Conformation in solution of side-chain liquid crystal polymers as a function of the mesogen-graft amount

The conformation of side-chain liquid crystal polymers with different mesogen-graft amounts has been studied by small-angle neutron scattering in dilute solutions of toluene-d8 and THF-d8. It is shown that the radius of gyration increases by about twofold when the mesogen-graft amount increases from 0 to 100%, which suggests that the persistence length of the backbone increases by about 4-fold. Comparison with the results reported in the literature on the melt state suggests that the persistence length is not an intrinsic property of side chain liquid crystal polymers, but depends on inter-chain interactions.     

Relational and overt aggression in preschool.

This research was designed as an initial attempt to assess relational aggression in preschool-age children. Our goal was to develop reliable measures of relational aggression for young children and to use these instruments to address several important issues (e.g., the relation between this form of aggression and social–psychological adjustment). Results provide evidence that relationally aggressive behaviors appear in children's behavioral repertoires at relatively young ages, and that these behaviors can be reliably distinguished from overtly aggressive behaviors in preschool-age children. Further, findings indicate that preschool girls are significantly more relationally aggressive and less overtly aggressive than preschool boys. Finally, results show that relational aggression is significantly related to social–psychological maladjustment (e.g., peer rejection) for both boys and girls. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in 4-year-old children's acquisition of vocabulary during storybook reading.

Two experiments were conducted to assess how children who differ in vocabulary knowledge learn new vocabulary incidentally from listening to stories read aloud. In both experiments, 4-yr-old children were classified as having either high or low word knowledge on the basis of a median split of their Peabody Picture Vocabulary Test—Revised (PPVT—R) standard scores. In Exp 1, children either listened passively or labeled pictures using novel words during the book readings. We found that children with larger vocabularies produced more novel words than did children with smaller vocabularies, and children who answered questions during the book readings comprehended and produced more words than did children who passively listened to the story. In Exp 2, children either listened to readings of a book, pointed to pictures during the readings, or labeled pictures during the readings. Children with larger vocabularies comprehended more novel words than did children with smaller vocabularies. Children who actively participated by labeling or pointing learned more words than did children who listened passively to book readings. Findings clarify the role of active responding by demonstrating that verbal and nonverbal responding are effective means of enhancing vocabulary acquisition. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A listener's investigation of printed word processing.

Examines the time course of lexical access in written-word recognition by comparing words with early and late uniqueness points (UPs). Three experiments, which used a normal (simultaneous) presentation of the letters under 3 different tasks (gender classification, naming, and semantic classification) provided no evidence for sequential processing. Rather, a small advantage in favor of words with late UP was found, which may be interpreted in terms of the lower n-gram frequencies of early-UP words. Exp 4 supported this interpretation and discussed an alternative interpretation in terms of parafoveal preview of the initial letters. A last experiment, which used an incremental presentation of the word letters, gave rise to a UP effect comparable in size to that obtained in an auditory study, suggesting that a temporal distribution of the signal is a sufficient condition for directional processing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Edge Stress Intensity Functions in Polyhedral Domains and their Extraction by a Quasidual Function Method

The solution to elastic isotropic problems in three-dimensional (3-D) polyhedral domains in the vicinity of an edge is provided in an explicit form. It involves a family of eigen-functions with their shadows, and the associated edge stress intensity functions (ESIFs), which are functions along the edges. Utilizing the explicit structure of the solution in the vicinity of the edge we use the quasidual function method, recently presented in [Omer et al. (2004). International Journal of Fracture 129:97–130] for scalar elliptic problems and in [Costabel et al. (2004). SIAM Journal of Mathematical Analysis 35(5), 1177–1202] in a general theoretical framework, for the extraction of ESIFs. This method provides a polynomial approximation of the ESIF along the edge whose order is adaptively increased so to approximate the exact ESIF. It is implemented as a post-solution operation in conjunction with the p-version finite element method. Numerical examples are provided in which we extract ESIFs associated with traction free or homogeneous Dirichlet boundary conditions in 3-D cracked domains or 3-D V-Notched domains. These demonstrate the efficiency, robustness and high accuracy of the proposed quasi-dual function method.     

Comparison of a static and a dynamic in vitro model to estimate the bioaccessibility of As, Cd, Pb and Hg from food reference materials Fucus sp. (IAEA-140/TM) and Lobster hepatopancreas (TORT-2)

Bioaccessibility, the fraction of an element solubilized during gastrointestinal digestion and available for absorption, is a factor that should be considered when evaluating the health risk of contaminants from food. Static and dynamic models that mimic human physiological conditions have been used to evaluate bioaccessibility. This preliminary study compares the bioaccessibility of arsenic (As), cadmium (Cd), lead (Pb) and mercury (Hg) in two food certified reference materials (CRMs) (seaweed: Fucus sp., IAEA-140/TM; Lobster hepatopancreas: TORT-2), using two in vitro gastrointestinal digestion methods: a static method (SM) and a dynamic multicompartment method (TIM-1). There are significant differences (p < 0.05) between the bioaccessible values of As, Cd, Pb and Hg obtained by SM and TIM-1 in the two CRMs. The specific form in which the elements studied are present in the CRM may help to explain the bioaccessibility values obtained.