Prevalence of vitamin D insufficiency in an adult normal population

Demethylation of some aconitine-type norditerpenoid alkaloids was carried out with trimethylsilyl iodide and with HBr in glacial AcOH. Aconitine (10), cammaconine (23), delphinine (3), falconerine (18), lappaconitine (22), and talatizamine (24) afforded partially demethylated products. When methoxyl groups are present at the C-16 and C-18 positions, these are demethylated, and the methoxyl group at the C-1 position underwent demethylation in none the alkaloids studied except falconerine (18). With HBr-AcOH, in the case of alkaloids possessing a C-3 hydroxyl group, the methoxymethyl at C-18 formed a tetrahydrofuran, cyclizing at the C-6 position. Detailed NMR spectral studies (1H, 13C, 1H homonuclear COSY, HETCOR, and selective INEPT) carried out on the demethylation products have enabled accurate chemical shift assignments to be made for the demethylated alkaloids.     

The way stylized language means: Pattern matching in the child ballads

This paper suggests ways in which the pattern-matching capability of the computer can be used to further our understanding of stylized ballad language. The study is based upon a computer-aided analysis of the entire 595,000- word corpus of Francis James Child'sThe English and Scottish Popular Ballads (1882–1892), a collection of 305 textual traditions, most of which are represented by a variety of texts. The paper focuses on the Mary Hamilton tradition as a means of discussing the function of phatic language in the ballad genre and the significance of textual variation.Cathy Lynn Preston is a Research Associate, Computer Research in the Humanities, at the University of Colorado, Boulder. She is interested in folklore, particularly oral narrative; popular literature of the 18th- and 19th-century, particularly broadside and chapbook; the works of John Gay, Jonathan Swift, Thomas Hardy; Middle English romance and lyric. Her major publications areA KWIC Concordance to Jonathan Swift's A Tale of a Tub, The Battle of the Books, and A Discourse Concerning the Mechanical Operation of the Spirit, A Fragment, (New York: Garland Publishing, 1984) (co-authored with Harold D. Kelling), andA KWIC Concordance to Thomas Hardy's Tess of the d'Urbervilles, (New York: Garland Publishing, 1989).     

Counter-Propagation Neural Networks for Molecular Sequence Classification: Supervised LVQ and Dynamic Node Allocation

A modified counter-propagation (CP) algorithm with supervised learning vector quantizer (LVQ) and dynamic node allocation has been developed for rapid classification of molecular sequences. The molecular sequences were encoded into neural input vectors using an n–gram hashing method for word extraction and a singular value decomposition (SVD) method for vector compression. The neural networks used were three-layered, forward-only CP networks that performed nearest neighbor classification. Several factors affecting the CP performance were evaluated, including weight initialization, Kohonen layer dimensioning, winner selection and weight update mechanisms. The performance of the modified CP network was compared with the back-propagation (BP) neural network and the k–nearest neighbor method. The major advantages of the CP network are its training and classification speed and its capability to extract statistical properties of the input data. The combined BP and CP networks can classify nucleic acid or protein sequences with a close to 100% accuracy at a rate of about one order of magnitude faster than other currently available methods.     

Target groups for preventing AIDS among intravenous drug users: II. The "hard" data studies.

Studies were reviewed with respect to three different target groups for preventing AIDS among intravenous (IV) drug users by (a) providing drug abuse treatment for those who want to stop injecting drugs, (b) providing "safer" injection for those who are likely to continue injecting, and (c) preventing drug injection among those who are at high risk for beginning to inject. The studies reviewed were limited to those that include "hard" data: validated self-reports, seroprevalence outcomes, or self-reports of behavior that is opposed to any of the demand characteristics generated by the research setting. For two groups of current IV drug users—those entering drug treatment and those continuing to inject—these hard data studies show rapidly induced AIDS risk reduction but suggest a need for large-scale change maintained over long time periods. In terms of preventing initial injection, alternative forms of intense drug use have emerged but have not supplanted drug injection, and basic knowledge of AIDS does not appear to deter initial drug injection. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

回收塑料的重新稳定化

高价值的应用是取得塑料回收在经济上成功的关键。部分应用实例说明聚烯烃的重新稳定化所带来的特点和益处及在PET回收中的产品升级的可能性，其中具体说明对材料的性能和长效性能的影响。     

Communication complexity and intrinsic universality in cellular automata

The notions of universality and completeness are central in the theories of computation and computational complexity. However, proving lower bounds and necessary conditions remains hard in most cases. In this article, we introduce necessary conditions for a cellular automaton to be “universal”, according to a precise notion of simulation, related both to the dynamics of cellular automata and to their computational power. This notion of simulation relies on simple operations of space–time rescaling and it is intrinsic to the model of cellular automata. Intrinsic universality, the derived notion, is stronger than Turing universality, but more uniform, and easier to define and study.Our approach builds upon the notion of communication complexity, which was primarily designed to study parallel programs, and thus is, as we show in this article, particulary well suited to the study of cellular automata: it allowed us to show, by studying natural problems on the dynamics of cellular automata, that several classes of cellular automata, as well as many natural (elementary) examples, were not intrinsically universal.     

Compatibility of polyvinyl alcohol and poly(methyl vinyl ether-co-maleic acid) blends estimated by molecular dynamics

The CSIR has developed a novel oxygen barrier technology for plastics packaging based on interpolymer complex formation between PVOH (polyvinyl alcohol) and PMVE-MA (poly(methyl vinyl ether-co-maleic acid)). As interpolymer complexation interactions are strongly dependent on stoichiometric ratios, the estimation of the optimum blend ratio is an important component of blend design.This study used molecular dynamics modelling to predict the ratio of optimum interaction for PVOH:PMVE-MA blends. Amorphous cells were constructed containing blends of short-chain repeat units of PVOH and PMVE-MA. The oligomers were equilibrated using both NVT and NPT dynamics and the cohesive energy densities (CED's) of the models were computed. From the CED's, energies of mixing and Flory-Huggins Chi Parameter (χ) values were estimated.The χ-values were negative for all blends, indicating favorable interaction between the two polymers. The minimum χ-values were found around 0.6-0.7 mass fraction of PMVE-MA, which agrees well with experimental viscosity results (this work), which indicated optimum interaction around 0.7 mass fraction PMVE-MA. These results confirm that molecular dynamics can be used as a tool for investigating interpolymer complexation phenomena.     

An ecological perspective on a river’s rights: a recipe for more effective water quality governance?

ABSTRACT

In several countries, the transfer of legal rights to rivers is being discussed as an approach for more effective water resources management. But what could this transfer mean in terms of a healthy river? We address this question by identifying the ecological requirements for naturally functioning rivers and then explore the demands which these requirements impose on society, the current policy responses to these requirements and whether the transfer of rights to the river could facilitate the preservation of healthy freshwater ecosystems.     

Circuit-Coupled ${bf t}_{0}hbox {-}phi$ Formulation With Surface Impedance Condition

A finite-element formulation based on the use of magnetic scalar potential is proposed. It allows to describe circuit-coupled electromagnetic formulation using magnetic scalar potential in presence of multiply connected solid conductors (with holes), treated by surface impedance condition. This formulation offers powerful solutions at a low cost. An example of application is given.