Design of complementary UWB printed monopole antennas using simple formulas

Simple design formulas for designing ultra wideband (UWB) antennas in the form of complementary planar monopoles are described and their validity is tested using full electromagnetic wave simulations and measurements. Assuming dielectric substrate with relative permittivity of 10.2, the designed antennas feature a small size of 13 mmtimes26 mm. They exhibit a 10 dB return loss bandwidth from 3 to more than 15 GHz accompanied by near omnidirectional characteristics and good radiation efficiency throughout this band

Redefining functional models of basal ganglia organisation: Role for the posteroventral pallidum in linguistic processing?

Traditionally the basal ganglia have been implicated in motor behavior, as they are involved in both the execution of automatic actions and the modification of ongoing actions in novel contexts. Corresponding to cognition, the role of the basal ganglia has not been defined as explicitly. Relative to linguistic processes, contemporary theories of subcortical participation in language have endorsed a role for the globus pallidus internus (GPi) in the control of lexical-semantic operations. However, attempts to empirically validate these postulates have been largely limited to neuropsychological investigations of verbal fluency abilities subsequent to pallidotomy. We evaluated the impact of bilateral posteroventral pallidotomy (BPVP) on language function across a range of general and high-level linguistic abilities, and validated/extended working theories of pallidal participation in language. Comprehensive linguistic profiles were compiled up to 1 month before and 3 months after BPVP in 6 subjects with Parkinson's disease (PD). Commensurate linguistic profiles were also gathered over a 3-month period for a nonsurgical control cohort of 16 subjects with PD and a group of 16 non-neurologically impaired controls (NC). Nonparametric between-groups comparisons were conducted and reliable change indices calculated, relative to baseline/3-month follow-up difference scores. Group-wise statistical comparisons between the three groups failed to reveal significant postoperative changes in language performance. Case-by-case data analysis relative to clinically consequential change indices revealed reliable alterations in performance across several language variables as a consequence of BPVP. These findings lend support to models of subcortical participation in language, which promote a role for the GPi in lexical-semantic manipulation mechanisms. Concomitant improvements and decrements in postoperative performance were interpreted within the context of additive and subtractive postlesional effects. Relative to parkinsonian cohorts, clinically reliable versus statistically significant changes on a case by case basis may provide the most accurate method of characterizing the way in which pathophysiologically divergent basal ganglia linguistic circuits respond to BPVP.

Historic Bridge Photographs: The Lahey Collection

Romeo Watkins Lahey (1887-1968) was a distinguished Queensland engineer. He graduated in engineering from the University of Sydney in 1914 and served in World War I from 1915 to 1918 with The Royal Australian Engineers. Following the war, he accepted an offer to remain for a period in England and studied town planning at the University of London. He visited Europe and collected a remarkable set of historic bridge photographs. In the course of this visit, he met Paul Sejourne, a distinguished French bridge engineer, the designer of at Ieast one of the bridges (at Fontpedrouse, pages 25-27) included in this set. When Lahey died, his wife Sybil and daughter Ann took steps to give this remarkable set of 58 historic bridge photographs to The University of Queensland. More recently, Lahey's daughters Ann Neale and Alison Drake have given a set of lantern plates collected by their father, many of which also have photographs of bridges. This volume is divided into three parts: (a) a biography of Romeo Watkins Lahey, written by his daughter, Ann Neale; (b) copies of the original set of 58 bridge photographs, and (c) copies taken from 32 lantern plates. To these have been added captions. Many of the original photographs carried titles; where these are available they have been printed in italics. Further work has been done to identify bridges and where possible the captions include the completion date, major dimensions, locations, and references to published works. Plates 8.1-10 are copies of drawings used as Figures in a book. These drawings have not been copied and the source has not been identified. Two lists of photographs and plates are included - the first in the order of the original collections and a second with bridges listed in the order of material, structural form and date. The collection is of remarkable value to any bridge historian, and is recommended for study by students.

Classical and quantum noise in electronic systems

We review the description of noise in electronic circuits in terms of electron transport. The Poisson process is used as a unifying principle. In recent years, much attention has been given to current noise in light-emitting diodes and laser diodes. In these devices, random events associated with electron transport are correlated with photon emission times, thus modifying both the current statistics and the statistics of the emitted light. We give a review of experiments in this area with special emphasis on the ability of such devices to produce subshot-noise currents and light beams. Finally we consider the noise properties of a class of mesoscopic devices based on the quantum tunnelling of an electron into and out of a bound state. We present a simple quantum model of this process which confirms that the current noise in such a device should be subshot-noise.

Data analysis in multiple-frequency bioelectrical impedance analysis

The performance of three analytical methods for multiple-frequency bioelectrical impedance analysis (MFBIA) data was assessed. The methods were the established method of Cole and Cole, the newly proposed method of Siconolfi and co-workers and a modification of this procedure. Method performance was assessed from the adequacy of the curve fitting techniques, as judged by the correlation coefficient and standard error of the estimate, and the accuracy of the different methods in determining the theoretical values of impedance parameters describing a set of model electrical circuits. The experimental data were well fitted by all curve-fitting procedures (r = 0.9 with SEE 0.3 to 3.5% or better for most circuit-procedure combinations). Cole-Cole modelling provided the most accurate estimates of circuit impedance values, generally within 1-2% of the theoretical values, followed by the Siconolfi procedure using a sixth-order polynomial regression (1-6% variation). None of the methods, however, accurately estimated circuit parameters when the measured impedances were low (<20 Omega) reflecting the electronic limits of the impedance meter used. These data suggest that Cole-Cole modelling remains the preferred method for the analysis of MFBIA data.

Novel composite membranes for gas separation: Preparation and performance

High performance composite membranes based on molecular sieving silica (MSS) were synthesized using sols containing silicon co-polymers (methyltriethoxysilane and tetraethylorthosilicate). Alpha alumina supports were treated with hydrochloric acid prior to sol deposition. Permselectivity of CO2 over CH4 as high as 16.68 was achieved whilst permeability of CO2 up to 36.7 GPU (10(-6) cm(3) (STP) cm(-2) . s(-1) . cm Hg-1) was measured. The best membrane's permeability was finger printed during various stages of the synthesis process showing an increase in CO2/CH4 permselectivity by over 25 times from initial support condition (no membrane film) to the completion of pore structure tailoring. Transport measurement results indicate that the membrane pretreated with HCl has highest permselectivity and permeation rate. In particular, there is a definite cut-off pore size between 3.3 and 3.4 angstroms which is just below the kinetic diameters of Ar and CH4. This demonstrates that the mechanism for the separation in the prepared composite membrane is molecular sieving (activated diffusion), rather than Knudsen diffusion.