The 20 and 30 GHz MMIC technology for future space communication antenna system

The development of fully monolithic gallium arsenide receive and transmit modules is described. These modules are slated for phased array antenna applications in future 30/20 gigahertz communications satellite systems. Performance goals and various approaches to achieve them are discussed. The latest design and performance results of components, submodules and modules are presented

The Role of Intellectual Virtues in the Development of the Science Teacher: An Initial Provocation

Initial, informal observations of work with pre-service chemistry and other science teachers suggest that a number of intellectual virtues are required, alongside a shift in identity, in order to help secondary school science students negotiate the pathway from ‘science learner’ to ‘scientist’. This article explores these virtues, the ontological shift that accompanies them and pedagogical suggestions for how these attributes might be promoted in a programme of pre-service training, along with suggestions for further empirical research which might form the basis of further investigation into these initial observations

A survey of fertilizer use from 2001-2003 for grassland and arable crops

End of project reportFarm management data for the years 2001-2003 from the Teagasc National Farm Survey (NFS) were used as the basis for this fertilizer use survey. The farms which took part in the survey were randomly selected to represent the major farm systems and sizes using information from the CSO Census of Agriculture 2000. Farms were classified into 6 main farm systems namely: dairying, dairying with other enterprises, cattle rearing, cattle with other systems, mainly sheep and tillage systems. These systems refer to the dominant enterprise in each group

MMIC technology for advanced space communications systems

The current NASA program for 20 and 30 GHz monolithic microwave integrated circuit (MMIC) technology is reviewed. The advantages of MMIC are discussed. Millimeter wavelength MMIC applications and technology for communications systems are discussed. Passive and active MMIC compatible components for millimeter wavelength applications are investigated. The cost of a millimeter wavelength MMIC's is projected

Monte Carlo simulations of infinitely dilute solutions of amphiphilic diblock star copolymers

Single-chain Monte Carlo simulations of amphiphilic diblock star copolymers were carried out in continuous space using implicit solvents. Two distinct architectures were studied: stars with the hydrophobic blocks attached to the core, and stars with the polar blocks attached to the core, with all arms being of equal length. The ratio of the lengths of the hydrophobic block to the length of the polar block was varied from 0 to 1. Stars with 3, 6, 9 or 12 arms, each of length 10, 15, 25, 50, 75 and 100 Kuhn segments were analysed. Four distinct types of conformations were observed for these systems. These, apart from studying the snapshots from the simulations, have been quantitatively characterised in terms of the mean-squared radii of gyration, mean-squared distances of monomers from the centre-of-mass, asphericity indices, static scattering form factors in the Kratky representation as well as the intra-chain monomer-monomer radial distribution functions.Comment: 12 pages, 11 ps figures. Accepted for publication in J. Chem. Phy

Conformations of dendrimers in dilute solution

Conformations of isolated homo- dendrimers of G=1-7 generations with D=1-6 spacers have been studied in the good and poor solvents, as well as across the coil-to-globule transition, by means of a version of the Gaussian self-consistent (GSC) method and Monte Carlo (MC) simulation in continuous space based on the same coarse-grained model. The latter includes harmonic springs between connected monomers and the pair-wise Lennard-Jones potential with a hard core repulsion. The scaling law for the dendrimer size, the degrees of bond stretching and steric congestion, as well as the radial density, static structure factor, and asphericity have been analysed. It is also confirmed that while smaller dendrimers have a dense core, larger ones develop a hollow domain at some separation from the centre.Comment: RevTeX, 14 pages, 19 PS figures, Accepted for publication in J. Chem. Phy

Linear laser diode arrays for improvement in optical disk recording for space stations

The design and fabrication of individually addressable laser diode arrays for high performance magneto-optic recording systems are presented. Ten diode arrays with 30 mW cW light output, linear light vs. current characteristics and single longitudinal mode spectrum were fabricated using channel substrate planar (CSP) structures. Preliminary results on the inverse CSP structure, whose fabrication is less critically dependent on device parameters than the CSP, are also presented. The impact of systems parameters and requirements, in particular, the effect of feedback on laser design is assessed, and techniques to reduce feedback or minimize its effect on systems performance, including mode-stabilized structures, are evaluated

The Porphyromonas gingivalis hemagglutinins HagB and HagC are major mediators of adhesion and biofilm formation

Porphyromonas gingivalis is a bacterium associated with chronic periodontitis that possesses a family of genes encoding hemagglutinins required for heme acquisition. In this study we generated ΔhagB and ΔhagC mutants in strain W83 and demonstrate that both hagB and hagC are required for adherence to oral epithelial cells. Unexpectedly, a double ΔhagB/ΔhagC mutant had less severe adherence defects than either of the single mutants, but was found to exhibit increased expression of the gingipain-encoding genes rgpA and kgp, suggesting that a ΔhagB/ΔhagC mutant is only viable in populations of cells that exhibit increased expression of genes involved in heme acquisition. Disruption of hagB in the fimbriated strain ATCC33277 demonstrated that HagB is also required for stable attachment of fimbriated bacteria to oral epithelial cells. Mutants of hagC were also found to form defective single and multi-species biofilms that had reduced biomass relative to biofilms formed by the wild-type strain. This study highlights the hitherto unappreciated importance of these genes in oral colonization and biofilm formation

Rights of passage: law and the biopolitics of dying

Deleuze and Law: Forensic Futures explores the relation between law and life and the advent of a politics of 'life'. How have recent events focused social, political and cultural attention on the living body and its maintenance and management? The central concept, through which the embodiment of the subject will be examined will be that of 'bio-power'. Articulated by Michel Foucault, but brought to attention more recently in the work of Giorgio Agamben, this concept recognises that the relation between life and law is both historical and necessary: the law must operate on bodies but can only do so by establishing a border between the body of the polity, and the mere life excepted from political concern. The contemporary advent of bio-politics occurs when the polity increasingly and invasively operates on this 'mere' life, and the body or organism – rather than the self – becomes the object of political management. The manner in which the body becomes the focus of contemporary power has led legal theory to explore new questions of the threshold between life and death and has led social theory to question the new extensions of the law and the polity into embodied life. The contributors explore the forensic shift in contemporary social theory and cultural sensibility from a number of perspectives. Description of book from publisher website at: http://www.palgrave.com