The use of graphical pinch analysis for visualizing water footprint constraints in biofuel production

A graphical pinch approach for analysis of water footprint constraints on biofuel production systems is presented. The technique is based on the composite curve method which was originally developed for carbon-constrained energy planning, which is extended in this paper based on the underlying similarities of source-sink allocation problems. The pinch analysis approach enables limiting water footprint conditions to be identified, and provides insights that are useful for planning the large-scale cultivation of biofuel crops. An illustrative case study based on the bioethanol program of the Philippines is solved using the proposed approach.     

Synthesis of property-based resource conservation network in palm oil mills with time-varying process disturbance

This article presents a mathematical model for resource conservation in a palm oil milling process via property integration. The focus is given to the clay bath system for kernel/shell separation based on flotation principle. In the present study, the clay bath separator is considered as a semi-batch unit under time-dependent process disturbance. This is different from previous works where it is simplified as a continuous unit. The design problem can be formulated as a nonlinear program based on a superstructure approach, with the objective set to minimize the fresh resource consumption. An illustrative case study is solved to demonstrate the proposed model.     

Implementing corporate ethics management and its comparison with the safety management system: a case study in Hong Kong

A case study of one general contracting construction organization in Hong Kong was undertaken. The study illustrates the current state of corporate ethics management in the implementation of a corporate code of ethics. The overall process of developing the corporate code of ethics from planning to implementation was investigated. It was found that the corporate management of the organization that was studied adopted a laissez‐faire approach in implementing its code at the project level. This means that there was no formal and unified cross‐organizational plan for implementing the code at the project level. The methods of communicating the corporate code of ethics to the members of the project team were left to the discretion of the individual project manager. The research findings also showed that different project managers adopted different methods of communication to disseminate the corporate code of ethics to members of their project team.     

Analysis of motor synergies utilization for optimal movement generation for a human-like robotic arm

Controlling human-like robots with musculoskeletal structure has been a challenging problem in engineering. In biological studies, motor synergy hypothesis has been proposed as a solution in order to control high degree-of-freedom and complex human body. In this paper, we focus on exploring the applicability of motor synergies in generating goal-directed movements by optimal control in a human-like robotic arm. We focus on three problems： 1） Can motor synergies facilitate the solving of optimal control problem？ 2） What properties should motor synergies have in order to achieve tasks？ 3） How should motor synergies be utilized better？ For the first problem we show that goal-directed movements can be achieved by utilizing motor synergies which have properties of achieving the goals. For the second problem, we testify motor synergies which have different properties and discover that energy efficiency is an important aspect in motor synergies which can also be utilized to achieve goal-directed movements. This discovery also implies that we can obtain motor synergies by other ways rather than from goal-directed optimal control signals. For the third problem, we show that the control complexity can be further reduced by utilizing a subset of motor synergies which are effective to achieve goals.     

Arrest of adult hippocampal neurogenesis in mice impairs single- but not multiple-trial contextual fear conditioning.

The role of adult hippocampal neurogenesis in contextual fear conditioning (CFC) is debated. Several studies demonstrated that blocking adult hippocampal neurogenesis in rodents impairs CFC, while several other studies failed to observe an impairment. We sought to determine whether different CFC methods vary in their sensitivity to the arrest of adult neurogenesis. Adult neurogenesis was arrested in mice using low-dose, targeted x-irradiation, and the effects of irradiation were assayed in conditioning procedures that varied in the use of a discrete conditioned stimulus, the number of trials administered, and the final level of conditioning produced. We demonstrate that irradiation impairs CFC in mice when a single-trial CFC procedure is used but not when multiple-trial procedures are used, regardless of the final level of contextual fear produced. In addition, we show that the irradiation-induced deficit in single-trial CFC can be rescued by providing preexposure to the conditioning context. These results indicate that adult hippocampal neurogenesis is required for CFC in mice only when brief training is provided. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Visualizing temporal cluster changes using Relative Density Self-Organizing Maps

We introduce a Self-Organizing Map (SOM)-based visualization method that compares cluster structures in temporal datasets using Relative Density SOM (ReDSOM) visualization. ReDSOM visualizations combined with distance matrix-based visualizations and cluster color linking, is capable of visually identifying emerging clusters, disappearing clusters, split clusters, merged clusters, enlarging clusters, contracting clusters, the shifting of cluster centroids, and changes in cluster density. As an example, when a region in a SOM becomes significantly more dense compared to an earlier SOM, and is well separated from other regions, then the new region can be said to represent a new cluster. The capabilities of ReDSOM are demonstrated using synthetic datasets, as well as real-life datasets from the World Bank and the Australian Taxation Office. The results on the real-life datasets demonstrate that changes identified interactively can be related to actual changes. The identification of such cluster changes is important in many contexts, including the exploration of changes in population behavior in the context of compliance and fraud in taxation.     

Systematic approach for conceptual design of an integrated biorefinery with uncertainties

The objective of this work is to present a systematic approach for conceptual design of an integrated biorefinery with maximum economic potential accounting for the predefined uncertainties in energy economics. Various parameters commencing from raw biomass feedstock, desired end products, to market price trend, technological constraints and system uncertainties at multi-periods are to be considered. A structural framework, integrated biorefinery pathway map which embeds and interconnects the latest processing technologies is first developed. Then, a robust optimisation model is adopted to determine the optimum network which handles the predefined sets of uncertainties in energy economics. To illustrate the proposed approach, a case study with two different scenarios of uncertainties is solved. Furthermore, a sensitivity analysis is also performed to identify the critical parameters of an integrated biorefinery.     

RF power characteristics of SiGe HBTs at cryogenic temperatures

This paper investigates the temperature dependence (from 77 to 300 K) of dc, ac, and power characteristics for n-p-n SiGe heterojunction bipolar transistors (HBTs) with and without selectively implanted collector (SIC). In SiGe HBTs without SIC, the valance band discontinuity at the base-collector heterojunction induces a parasitic conduction band barrier while biasing at saturation region and high current operation at cryogenic temperatures. This parasitic conduction band barrier significantly reduces the current gain and cutoff frequency. For transistors biased with fixed collector current, the measured output power, power-added efficiency, and linearity at 2.4 GHz decrease significantly with decreasing operation temperatures. The temperature dependence of output power characteristic is analyzed by Kirk effect, current gain, and cutoff frequency at different temperatures. The parasitic conduction band barrier in SiGe HBTs with SIC is negligible, and thus the device achieves better power performance at cryogenic temperatures compared with that in SiGe HBT without SIC.     

Measurement invariance versus selection invariance: Is fair selection possible?

This article shows that measurement invariance (defined in terms of an invariant measurement model in different groups) is generally inconsistent with selection invariance (defined in terms of equal sensitivity and specificity across groups). In particular, when a unidimensional measurement instrument is used and group differences are present in the location but not in the variance of the latent distribution, sensitivity and positive predictive value will be higher in the group at the higher end of the latent dimension, whereas specificity and negative predictive value will be higher in the group at the lower end of the latent dimension. When latent variances are unequal, the differences in these quantities depend on the size of group differences in variances relative to the size of group differences in means. The effect originates as a special case of Simpson's paradox, which arises because the observed score distribution is collapsed into an accept-reject dichotomy. Simulations show the effect can be substantial in realistic situations. It is suggested that the effect may be partly responsible for overprediction in minority groups as typically found in empirical studies on differential academic performance. A methodological solution to the problem is suggested, and social policy implications are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Specific, irreversible inactivation of the epidermal growth factor receptor and erbB2, by a new class of tyrosine kinase inhibitor

A class of high-affinity inhibitors is disclosed that selectively target and irreversibly inactivate the epidermal growth factor receptor tyrosine kinase through specific, covalent modification of a cysteine residue present in the ATP binding pocket. A series of experiments employing MS, molecular modeling, site-directed mutagenesis, and 14C-labeling studies in viable cells unequivocally demonstrate that these compounds selectively bind to the catalytic domain of the epidermal growth factor receptor with a 1:1 stoichiometry and alkylate Cys-773. While the compounds are essentially nonreactive in solution, they are subject to rapid nucleophilic attack by this particular amino acid when bound in the ATP pocket. The molecular orientation and positioning of the acrylamide group in these inhibitors in relation to Cys-773 entirely support these results as determined from docking experiments in a homology-built molecular model of the ATP site. Evidence is also presented to indicate that the compounds interact in an analogous fashion with erbB2 but have no activity against the other receptor tyrosine kinases or intracellular tyrosine kinases that were tested in this study. Finally, a direct comparison between 6-acrylamido-4-anilinoquinazoline and an equally potent but reversible analog shows that the irreversible inhibitor has far superior in vivo antitumor activity in a human epidermoid carcinoma xenograft model with no overt toxicity at therapeutically active doses. The activity profile for this compound is prototypical of a generation of tyrosine kinase inhibitors with great promise for therapeutic significance in the treatment of proliferative disease.