Determination of sulphadimidine in animal feedstuffs by an enzyme-linked immunoassay

An enzyme immunoassay technique for the determination of sulphadimidine in animal feedstuffs has been developed. The antibody showed limited cross-reactivity with other drugs, including sulphonamides, used as feed additives. Using spiked samples recoveries of 80-88% were obtained. The limit of detection of the assay was 70 ng/g.     

A mathematical model and numerical investigation for determining the hydraulic conductivity of rocks

Transient flow analysis has numerous geophysical and geotechnical applications, and is necessary for the understanding and development of laboratory measurement techniques in rock and soil mechanics, particularly permeability testing. In this paper, a hydraulic pump flow permeability test is mathematically modelled reducing the problem to the time-dependent diffusion equation with unknown spacewise dependent material property coefficients. This equation is solved subject to certain boundary conditions and, with limited additional available boundary measurements in time, of the pressure and/or hydraulic flux. Both experimental and numerically simulated noisy data are inputted into the formulation of the inverse problem. The numerical solution of the inverse problem obtained from a finite-difference method (FDM), combined with an ordinary least-squares approach, is compared with the exact solution for homogeneous and heterogeneous materials with constant, linear and quadratic spatially dependent hydraulic conductivity, subjected to one-dimensional, pump-flow hydraulic boundary conditions. The numerically obtained results, based on an optimal selection of the limited number of time measurements, are consistent with the sensitivity analysis performed prior to inversion. The identifiability and stability of the inverse problem are also numerically investigated.     

The design of slot arrays including internal mutual coupling

Improved array performance (lower sidelobe levels, a better input match) requires elimination of approximations in earlier design procedures. One important change is to include internal higher order mode coupling. That is done here and is found to cause a simple but significant change in existing design formulas.     

Algorithm for multichannel LMS adaptive filtering

A modification of the LMS algorithm is presented in which the coefficients of an array of FIR filters, whose outputs are linearly coupled to an array of sensors, are adapted to minimise the mean-square sum of the error signals from these sensors. The application of the algorithm to the control of distributed parameter systems is discussed.     

Resonant length of longitudinal slots and validity of circuit representation: Theory and experiment

Pertinent theory for the design of longitudinal slot arrays is reviewed and its dependence on the dominant mode scattering off a single slot is pinpointed. The critical need to know resonant length versus slot offset is emphasized and the desirability of determining this information theoretically rather than experimentally is argued. Then method of moments solutions are used to calculate resonant length versus slot offset for given waveguide dimensions and frequency. These theoretical results are compared to new, carefully obtained experimental data. Agreement is found to be so good, it is concluded that one can dispense with the costly gathering of experimental input data when designing longitudinal slot arrays fed by standard rectangular waveguide. A critical look is taken at the validity of representing the longitudinal slot as a shunt element on an equivalent transmission line. This assumption is found to be more and more questionable as thebdimension is reduced. For quarter-height guide, an alternate design procedure is suggested as being more accurate.     

Measurement of IP3 in p-i-n photodetectors and proposed performancerequirements for RF fiber-optic links

The nonlinearities generated by wide-band, high-current photodetectors are discussed in the context of the performance of an externally modulated analog radio-frequency fiber-optic link. The quantitative impart of the detector's third-order intermodulation product intercept (IP3) on the link's spur-free dynamic range is analyzed. Waveguide p-i-n photodiodes were developed to specifically address these stringent IP3 goals. The IP3 was measured using a four laser heterodyne system resulting in an IP3 of 27 dBm measured at a center frequency of 20 GHz with 20 mA of de photocurrent. The authors believe that this is the highest photodetector IP3 reported to date at these operating conditions     

Design of a 3-D fully depleted SOI computational RAM

We introduce a three-dimensional (3-D) processor-in-memory integrated circuit design that provides progressively increasing processing power as the number of stacked dies increases, while incurring no extra design effort or mask sets. Innovative techniques for processor/memory redundancy and fast global bus evaluation are described. The architecture can be augmented with a nearest-neighbor physical 3-D communications network that can substantially reduce interconnect lengths and relieve routing congestion. The test chip, with 128 Kb of memory and 512 processing elements (PEs) on two fully depleted silicon-on-insulator (SOI) dies, can achieve a peak of 170 billion-bit-operations per second at 400 MHz.     

Information states in stochastic control and filtering: a Liealgebraic theoretic approach

The purpose of the paper is two-fold: (i) to introduce the sufficient statistic algebra which is responsible for propagating the sufficient statistics, or information state, in the optimal control of stochastic systems and (ii) to apply certain Lie algebraic methods and gauge transformations, widely used in nonlinear control theory and quantum physics, to derive new results concerning finite dimensional controllers. This enhances our understanding of the role played by the sufficient statistics. The sufficient statistic algebra enables us to determine a priori whether there exist finite-dimensional controllers; it also enables us to classify all finite-dimensional controllers. Relations to minimax dynamic games are delineated     

Getting academic jobs: Women appear to be equally successful without being equally qualified.

In response to the study by P. Bronstein et al (see record 1986-20846-001) concerning the relation of sex of the candidate to job success in the academic world, questions are raised about statistical interpretations, and it is suggested that speed of change in the sex composition of faculties depends primarily on retirement. (PsycINFO Database Record (c) 2010 APA, all rights reserved)