Apparatus and procedure for measuring release rates from formulations of lepidopteran semiochemicals

An apparatus was developed wherein a vacuum source was used to pull air across a controlled-release-formulation dispenser or a planchet containing a known quantity of a semiochemical and into a collector filled with a polymeric adsorbent. After a set time, the semiochemical was eluted with solvent and was quantified by gas-liquid chromatography (GLC). High percentages of known quantities of the lepidopteran semiochemicals (Z)-7-dodecen-l -ol acetate (Z7DDA), boiling point (bp) 275 ° C/1 atm, (Z)-9-tetradecen-1-ol formate (Z9TDF), bp 289 °C/1 atm, and (Z,Z)-3,13-octadecadien-1-ol acetate (ZZODDA), bp 490 °C/1 atm, were recovered. The semiochemicals did not oxidize and were recovered quantitatively from the adsorbent. The release rates of Z9TDF from a controlled-release dispenser were found to be directly proportional to the airflow rates. Release rate measurements on the Z9TDF dispensers were made for the purpose of estimating the method's precision. The method was shown to give internally consistent results by measurements on another Z9TDF formulation. The accuracy of the method is discussed.Mention of a commercial or proprietary product in this paper does not constitute an endorsement by the USDA.     

Development of Habitat Suitability Criteria and In‐Stream Habitat Assessment for the Benthic Cyanobacteria Phormidium

Global demand for freshwater has led to unprecedented levels of water abstraction from riverine systems. This has resulted in large alterations in natural river flows. The deleterious impacts of reduced flows on fish and macroinvertebrate abundances have been thoroughly investigated; in contrast, there is a limited understanding of the potential for changes in the abundance of nuisance benthic algal/cyanobacterial blooms. In New Zealand, Phormidium sp. blooms are common in numerous rivers during summer low flows. In this study, an in‐stream habitat assessment is used to examine the relationship between Phormidium habitat availability and reducing flows. Over 650 observations of Phormidium mats, from seven sites (Hutt River, lower North Island, New Zealand), were used to construct habitat suitability curves for depth, velocity and substrate. Preference curves were fitted using both the ‘forage ratio’ and ‘quantile regression’ methods. Phormidium growth, observed at all seven sites, increased significantly from upstream (uppermost site, 5.2% mat cover) to downstream (63.5%). The habitat suitability curves revealed Phormidium had a large tolerance to velocity, depth and substrate type. Consequently, decreases in flow had only negligible effects on available Phormidium habitat. During periods of stable flow, Phormidium abundance positively correlated with increased nitrogen concentrations, potentially explaining the large variation in Phormidium cover from upstream to downstream. Quantile regression generated habitat suitability criteria were a more accurate predictor of available Phormidium habitat than the forage ratio criteria. Copyright © 2013 John Wiley & Sons, Ltd.     

Discriminating Conduct: Deploying Systems to Support Awareness in Organizations

Alongside the emergence of the use of fieldwork studies for design there has been a discussion on how best these studies can inform system development. Concerns have been expressed as to whether their most appropriate contribution is a list of requirements or design recommendations. This article explores a recurrent issue that has emerged from fieldwork studies in Computer-Supported Cooperative Work, awareness, and with respect to a particular system development project discusses some of the implications for the development and deployment of one particular kind of technology—image recognition systems—in particular, organizational settings. In the setting in question—surveillance centers or operations rooms—staff utilize a range of practices to maintain awareness. Rather than extending field studies so that they can better assist design, it may be considered how workplace studies can contribute to a respecification of key concepts, like awareness, that are critical to an understanding of how technologies are used and deployed in everyday environments.     

Object-Oriented Systems Development

Object-oriented design is an approach to systems development that proposes the use of system objects to build new systems and rebuild old ones. An important goal of object-oriented development is to change the nature of traditional software development from designing and writing models from scratch to building systems through the assembly of reusable software objects. This article discusses the productivity potential as well as the limitations of object-oriented systems development and makes recommendations for its use.     

Determinants of the inhibitory action of purified 14-kDa phospholipases A2 on cell-free prothrombinase complex

It has been suggested (Kini, R. R., and Evans, H. J. (1987) J. Biol. Chem. 262, 14402-14407) that the anticoagulant activity of members of the 14-kDa phospholipase A2 (PLA2) family depends on the presence of basic residues within a variable surface region (residues 54-77) distinct from both the conserved catalytic machinery and surface sites mediating the antibacterial action of these enzymes (see Weiss, J., Inada, M., Elsbach, P., and Crowl, R. M. (1994) J. Biol. Chem. 269, 26331-26337). To further define the determinants of the anticoagulant activity of PLA2, we have analyzed the inhibitory effects of purified native and recombinant PLA2 on cell-free prothrombinase. Both native and recombinant wild-type pig pancreas (net charge -1) and human "secretory" PLA2 (net charge +15) produced similar dose-dependent inhibition of prothrombinase activity that was significantly less potent than a toxic PLA2 purified from snake venom. Site-specific mutations that either increased or decreased PLA2 activity toward bactericidal/permeability-increasing protein-treated Escherichia coli by up to 50-fold had no effect on antiprothrombinase activity. In contrast, substitution of Arg for Asp-59/Gly for Ser-60 in the pig PLA2 increased antiprothrombinase activity by 5-10-fold without affecting catalytic activity toward a range of phospholipid substrates or antibacterial activity. Comparison of antiprothrombinase activity of catalytically active and inactive forms of the PLA2 and under a range of phospholipid conditions revealed that the potent antiprothrombinase activity of native toxic venom PLA2 and of the D59R.S60G mutant pancreatic PLA2 reflect combined catalytic and noncatalytic actions, the latter apparently dependent on basic residues at discrete surface sites in the enzyme.     

Iterative optimization of high-affinity proteases inhibitors using phage display. 1. Plasmin

We generated a series of libraries having variants of the first Kunitz domain of human lipoprotein-associated coagulation inhibitor (LACI-D1, also known as tissue-factor pathway inhibitor-I) displayed on bacteriophage M13 as pIII-fusions. We varied LACI-DI iteratively in two regions: the P1 region (positions 10-21) and the "second loop", (positions 31-39), which together form one end of the domain. Display-phage library Lib#1 allows 31 200 amino-acid sequences in P1 region (residues 13, 16-19). Preliminary, we screened Lib#1 against human plasmin (PLA, EC 3.4.21.7) immobolized on agarose to enrich for phage displaying variants with PLA affinity. We introduced a 1600-fold increase in second-loop diversity (residues 31, 32, 34, 39) into the population of selectants from Lib#1, yielding Lib#2. Lib#2 (allowing approximately 50 million amino-acid sequences) was screened against PLA-agarose to isolate highest affinity binders. Protein EPI-P211, derived from the best isolate of Lib#2, inhibits PLA with Ki = 2 nM (at least 500-fold better than LACI-D1) and with high specificity. We used amino-acid sequences of PLA-binding selectants to design a PLA-biased library (Lib#3) which we screened against PLA. The protein EPI-P302 (derived from the best binder obtained from Lib#3) has Ki for PLA inhibition of 87 pM, which is 25-fold better than the first-round best binder and > or = 12 500-fold better than LACI-D1. EPI-P302 also shows very high specificity for PLA vs other human proteases and is resistant to inactivation by oxidants and extremes of temperature or pH. Thus, one can use selectants from one library to design target-tailored combinatorial libraries and obtain quite stable, highly specific, very high-affinity binding molecules while maintaining an essentially human framework.     

Coherency Hub Design for Multisocket Sun Servers with CoolThreads Technology

CoHub, a coherency hub ASIC, provides a cost-effective way to extend a glueless two-node chip-multithreading system to a four-node system without changes to the processor. The four-node, 256-thread system achieves near-linear scaling of performance with thread count on transaction-processing workloads. Time-to-market pressure, 800-MHz operation, and a six-stage pipeline were among the constraints that shaped CoHub's design.     

New global optimization algorithms for model-based clustering

The Expectation-Maximization (EM) algorithm is a very popular optimization tool for mixture problems and in particular for model-based clustering problems. However, while the algorithm is convenient to implement and numerically very stable, it only produces local solutions. Thus, it may not achieve the globally optimal solution in problems that have a large number of local optima. This paper introduces several new algorithms designed to produce global solutions in model-based clustering. The building blocks for these algorithms are methods from the operations research literature, namely the Cross-Entropy (CE) method and Model Reference Adaptive Search (MRAS). One problem with applying these methods directly is the efficient simulation of positive definite covariance matrices. We propose several new solutions to this problem. One solution is to apply the principles of Expectation-Maximization updating, which leads to two new algorithms, CE-EM and MRAS-EM. We also propose two additional algorithms, CE-CD and MRAS-CD, which rely on the Cholesky decomposition. We conduct numerical experiments of varying complexity to evaluate the effectiveness of the proposed algorithms in comparison to classical EM. We find that although a single run of the new algorithms is slower than a single run of EM, all have the potential for producing significantly better solutions. We also find that although repeat application of EM may achieve similar results, our algorithms provide automated, data-driven decision rules which may significantly reduce the burden of searching for the global optimum.