The estimation of stochastic cost-quantity frontiers for discretionary cost and budgeted-expenditure systems

Two alternative approximating functions for representing the unknown composite residual density function of a cost-quantity frontier are examined. The frontier is one in which cost is regarded as preselected. This is appropriate for public sector economics and discretionary cost situations. One function requires the estimation of a single distribution parameter, whereas the other makes no a priori assumption on the shape of the density function.     

Surjectivity for Hamiltonian loop group spaces

Let G be a compact Lie group, and let LG denote the corresponding loop group. Let (X,) be a weakly symplectic Banach manifold. Consider a Hamiltonian action of LG on (X,), and assume that the moment map :XL ^* is proper. We consider the function ||²:X, and use a version of Morse theory to show that the inclusion map j:^-1(0)X induces a surjection j ^*:H _G ^*(X)H _G ^*(^-1(0)), in analogy with Kirwans surjectivity theorem in the finite-dimensional case. We also prove a version of this surjectivity theorem for quasi-Hamiltonian G-spaces.     

Tame combing and almost convexity conditions

We give the first examples of groups which admit a tame combing with linear radial tameness function with respect to any choice of finite presentation, but which are not minimally almost convex on a standard generating set. Namely, we explicitly construct such combings for Thompson??s group F and the Baumslag?CSolitar groups BS(1, p) with p ??? 3. In order to make this construction for Thompson??s group F, we significantly expand the understanding of the Cayley complex of this group with respect to the standard finite presentation. In particular we describe a quasigeodesic set of normal forms and combinatorially classify the arrangements of 2-cells adjacent to edges that do not lie on normal form paths.     

Inclusive Science Education: Classroom Teacher and Science Educator Experiences in CLASS Workshops

Inclusion is the meaningful participation of students with disabilities in general education classrooms. The CLASS project (Creating Laboratory Access for Science Students) is a unique initiative offering training and resources to help educators provide students with a variety of physical, sensory and learning disabilities equal access in the science laboratory or field. To determine whether participants believed a 2‐week residential workshop sponsored by CLASS raised disability awareness and provided teacher training in inclusive science teaching practice, a multipoint Likert scale survey and questionnaire was completed by all participants (N= 20) in four workshops. Participants reported large gains in their preparedness to teach science to students with disabilities. Participants also reported gains in their familiarity with instructional strategies, curricula, and resources and their ability to design, select, and modify activities for students with disabilities. Finally, shifts in attitudes about teaching science to students with disabilities were noted.     

Next Generation Science Standards: A National Mixed‐Methods Study on Teacher Readiness

Next Generation Science Standards (NGSS) science and engineering practices are ways of eliciting the reasoning and applying foundational ideas in science. As research has revealed barriers to states and schools adopting the NGSS, this mixed‐methods study attempts to identify characteristics of professional development (PD) that will support NGSS adoption and to improve teacher readiness. In‐service science teachers from across the nation were targeted for the survey and responses represented 38 states. Research questions included: How motivated and prepared are in‐service 7–12 teachers to use NGSS science and engineering practices? What is the profile of 7–12 in‐service teachers who are motivated and feel prepared to use NGSS science and engineering practices? The study revealed that teachers identified engineering most frequently as a PD need to improve their NGSS readiness. High school teachers rated themselves as more prepared than middle school and all teachers who use Modeling Instruction expressed higher NGSS readiness. These findings and their specificity contribute to current knowledge, and can be utilized by districts in selecting PD to support teachers in preparing to implement the NGSS successfully.     

Highly selective synthesis of catalytically active monodisperse rhodium nanocubes

Monodisperse sub-10 nm Rh nanocubes were synthesized with high selectivity (>85%) by a seedless polyol method. The {100} faces of the Rh NCs were effectively stabilized by chemically adsorbed Br- ions from trimethyl(tetradecyl)ammonium bromide (TTAB). This simple one-step polyol route can be readily applied to the preparation of Pt and Pd nanocubes. Moreover, the organic molecules of PVP and TTAB that encapsulated the Rh nanocubes did not prevent catalytic activity for pyrrole hydrogenation and CO oxidation.     

Particle size distributions of silver nanoparticles at environmentally relevant conditions

Silver nanoparticles (Ag NPs) are becoming increasingly popular as antimicrobial agents in consumer goods with consequent risk to environmental health from discharges. Environmentally relevant fate and transport investigations are limited but essential to gain understanding towards bioavailability and toxicology. In this study, monodisperse 15 nm citrate-stabilised Ag NPs were synthesised, characterised and then fractionated by flow field-flow fractionation (FlFFF) at environmentally relevant conditions (pH 5 or 8, presence of natural organic macromolecules (NOM) and presence of sodium or calcium). At low ionic strength, Ag NPs particle size increased as pH increased from 5 to 8. However, changing the ionic strength from 10⁻³ to 10⁻² M Na increased instability of the Ag NPs, and loss of peak at pH 5 but in the presence of humic substance (HS), a reduction in NP size was seen, most likely due to a reduction in the diffuse layer. The presence of Ca²⁺ ions, at the higher ionic strengths caused complete loss of the solution Ag NPs with or without HS, most likely due to aggregation. At the lower Ca²⁺ ionic strength the Ag NPs were still unstable, but again, in the presence of HS the NPs were largely dispersed. The presence of HS improved stability of Ag NPs under these conditions by forming a surface coating resulting in both steric and charge stabilisation. This work implies that Ag NPs could have long residence times in aquatic systems in the presence of HS potentially resulting in increased bioavailability.     

Analytical selenoamino acid studies by chromatography with interfaced atomic mass spectrometry and atomic emission spectral detection

Consumption of selenium enriched plants or yeast-based nutritional supplements has been reported to provide anticarcinogenic benefits which are selenium compound dependent. Separation and identification of these selenium compounds is critical to understand the activity. Plants and yeast convert inorganic selenium in the soil or growth media into organoselenium compounds, probably following a route similar to the sulfur assimilatory pathway. Non-volatile selenium compounds produced include selenoamino acids, some of which have shown anticarcinogenic activity. Volatile compounds produced by chemical reaction of involatile precursors have also been found. An ion pair chromatographic method with ICP-MS detection for the separation of selenoamino acid standards potentially present in real samples is given. The method allows separation of selenoamino acids including such analytes as the cis-trans isomers of Se-1-propenyl-dl-selenocysteine. The method also provides the capability of determining the presence of selenoxides and possibly selenones, and tracking of other functionalities and reactions by selective derivatization. Alternatively, selenoamino acids are treated with ethylchloroformate to produce stable volatile derivatives which are amenable to GC separation with element specific atomic emission detection (GC-AED). Results of total selenium determination and speciation of selenium enriched yeast-based nutritional supplements, selenium enriched allium vegetables and bioremediation samples are presented.     

Spectrophotometric determination of rifampicin through chelate formation and charge transfer complexation in pharmaceutical preparation and biological fluids

Two simple and accurate spectrophotometric methods for determination of Rifampicin (RIF) are described. The first method is based on charge transfer (CT) complex formation of the drug with three pi-electron acceptors either 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,7,8-Tetracyanoquinodimethane (TCNQ) or 2,3,5,6-Tetrachloro-1,4-benzoquinone (p-chloranil) in acetonitrile. The method is followed spectrophotometrically by measuring the maximum absorbance at 584 nm, 761 nm (680 nm) or 560 nm for DDQ, TCNQ and p-chloranil, respectively. Under the optimized experimental conditions, the calibration curves showed a linear relationship over the concentration ranges of 5-140 microg/ml, 2-45 microg/ml (5-120 microg/ml) and 15-200 microg/ml, respectively. The second method is based on the reaction of RIF with iron(III) forming a water insoluble violet complex which is extracted into chloroform. The method determines RIF in concentration range of 10-240 microg/ml at 540 nm. The proposed methods applied to determination of RIF in capsule, human serum and urine samples with good accuracy and precision. The results were compared statistically with the official method and showed no significant different between the methods compared in terms of accuracy and precision.     

Substituent electronic effects in chiral ligands for asymmetric catalysis

The majority of reports of ligand modification for catalysis have followed from systematic variation of the spatial demands of the catalyst. The focus of this review is to highlight selected major contributions to the area of substituent controlled electronic-tuning of some well known chiral ligands and the subsequent effect of these changes during asymmetric catalysis. The ligand types discussed include the salens, phosphites and phosphoramidites, ferrocene-containing ligands, oxazolines and axially chiral ligands. For each ligand type we attempt analyse the effect of systematic variation of electronics and note whether any improvements in catalyst activity and selectivity are obtained.