Bounding the Inefficiency of the Reliability-Based Continuous Network Design Problem Under Cost Recovery

Networks and Spatial Economics - This study defines the price of anarchy for general reliability-based transport network design problems, which is an indicator of inefficiency that reveals how much...     

二种风格美丽成就冬季时尚风潮

漫长的冬季，如果缺少色彩绚丽、造型惊艳的珠宝，难免会让人觉得少了几分情趣，尽管在这个季节里充满了黑白灰。但多了些童话般的浪漫和特立独行的创意而那些特殊材质的夸张设计和充满几何图形的组合，让我们体味到久违的时尚[编者按]     

Chemical structure—normal force relationships in polymer glasses

In previous work, we found that the normal force responses in poly(methyl methacrylate) (PMMA) and poly(ethyl methacrylate) (PEMA) subjected to torsional deformations were strongly influenced by their prominent β-relaxation mechanisms which are related to the n-alkyl methacrylate side group motions. Using the concept of an elastic stress relaxing material we were able to extract the derivatives of the strain energy density function with respect to the first and second invariants of the deformation tensor (W₁ and W₂). In the present work, we report results from two materials, polysulfone (PSF) and polycarbonate (PC), with weak β-relaxations that are due to main chain motions. We find that for the two materials, the difference from neo-Hookean behavior is real though very small, contrary to the large deviations from neo-Hookean behavior observed for PMMA and PEMA. The results support the contention that the large normal force responses and the consequent strongly non neo-Hookean behavior of the glassy n-alkyl methacrylates is due to the side chain.     

The business environment of the construction industry in Nigeria

The business environment of any industry consists of systems and structures, which determine the atmosphere under which all the business of that industry is transacted. They affect directly or indirectly all practitioners of that industry, without their being able to influence it. In a scientific investigation into the problems of the construction industry in Nigeria, out of the 47 variables identified that can adversely affect the construction industry, 37 variables were classified under the environment of the construction industry. Of the 18 variables considered to constitute the most serious problems, which occur all the time, 17 variables were related to the business environment of the construction industry. This paper reviews the research findings with respect to the business environment of the construction industry in Nigeria and discusses the implications of some of the findings.     

NO Formation by Neuronal NO‐Synthase can be Controlled by Ultrafast Electron Injection from a Nanotrigger

Synchronized catalysis in native enzyme : We used a photoactive nanotrigger (NT) to study the initial electron transfer to FAD in native neuronal NOS catalysis. Modeling and fluorescence spectroscopy showed that selective NT binding to NADPH sites is able to override Phe1395 regulation, thus permitting ultrafast injection of electrons into the protein electron pathway. That NT initiation of flavoenzyme catalysis led to the formation of NO is promising for time‐resolved X‐ray and other cellular applications.

     

An approach for sub-ontology evolution in a distributed health care enterprise

In response to the changing nature of health issues, standardized health ontologies such as SNOMED CT and UMLS incline to change more frequently than most other domain ontologies. Yet, semantic interoperability shared among institutions within a distributed health care enterprise relies heavily on the availability of a valid and up-to-date standardized ontology. In this paper, we propose the creation and preservation of sub-ontologies to deal with the frequent changes in health ontologies. Our approach focuses on the nature and characteristics of standard health ontologies, however it can also be applied to other domain ontologies with similar characteristics. Our sub-ontology evolution approach defines ways to create valid sub-ontologies for each specific health application, and to effectively develop a series of propagation mechanism when the main ontology changes. Our approach will (i) isolate the required change propagation to the relevant health applications that utilized the changing concepts only, and (ii) optimize the propagation mechanism to include the minimum number of operations only. Since a sub-ontology should be a valid ontology by itself, the change propagation approach used in this process should contain the rules to assure the validity of the produced sub-ontology while keeping the consistency of the sub-ontology to the evolved base ontology. A change identification process, which considers the nature of the health ontology change logs, is conducted to identify the semantics of the changes. From the evaluation, it is shown that the content of the evolved sub-ontologies produced using our approach is consistent to the evolved base ontology. Moreover, the propagation process can be performed more efficiently because the number of operations required for our change propagation method is lower than the number of operations required for direct re-extraction from the evolved base ontology.     

LC-DAD-MS/SPE-NMR hyphenation. A tool for the analysis of pharmaceutically used plant extracts: identification of isobaric iridoid glycoside regioisomers from Harpagophytum procumbens

LC-DAD-MS monitored fractionation of a Harpagophytum procumbens DC. (Pedaliaceae) root extract was combined with a hyphenated LC-DAD-MS/SPE-NMR technique, thus providing the spectral data needed for structure elucidation. This approach allowed the characterization of isobaric iridoid glycoside regioisomers present only as minor constituents. The analytes were identified as the (E/Z) pairs of 6'-O-(p-coumaroyl)harpagide (6'-PCHG) and 8-O-(p-coumaroyl)-harpagide (8-PCHG). The fact that 8-(Z)-PCHG constitutes a new natural product underlines the analytical power of this combined approach. Furthermore, derivatives 6'-(Z)- and 6'-(E)-PCHG are new constituents for H. procumbens.