Synthetic aperture radar autofocus based on a bilinear model

Autofocus algorithms are used to restore images in nonideal synthetic aperture radar imaging systems. In this paper, we propose a bilinear parametric model for the unknown image and the nuisance phase parameters and derive an efficient maximum-likelihood autofocus (MLA) algorithm. In the special case of a simple image model and a narrow range of look angles, MLA coincides with the successful multichannel autofocus (MCA). MLA can be interpreted as a generalization of MCA to a larger class of models with a larger range of look angles. We analyze its advantages over previous extensions of MCA in terms of identifiability conditions and noise sensitivity. As a byproduct, we also propose numerical approximations to the difficult constant modulus quadratic program that lies at the core of these algorithms. We demonstrate the superior performance of our proposed methods using computer simulations in both the correct and mismatched system models. MLA performs better than other methods, both in terms of the mean squared error and visual quality of the restored image.     

Resolution Of N-Benzyl-Erythro-β-Hydroxy-DL-Aspartic Acid

Dakin's method for the resolution of erythro-β-hydroxy-DL-aspartic acid gives only incomplete separation. The N-benzyl derivative of this amino acid, however, has been resolved by means of L-histidine. Both antipodes are obtained optically pure and in practically quantitative yield.     

Occasional transsynaptic viral labeling in the central nervous system from the polycystic ovary induced by estradiol valerate

Increased density of catecholaminergic nerves in the human polycystic ovary has been observed. The aim of the present study was to investigate the distribution of transsynaptically virus-labeled neurons in the central nervous system from the rat polycystic ovary to see whether is it different or not from that of cycling control rats. To induce a polycystic ovary, a single injection of estradiol valerate was given to adult female rats and 30 days later a neurotropic virus was injected into the right ovary. Rats were sacrificed 72 or 96 hours after viral infection. Weight of the ovaries of the estradiol valerate-treated rats was significantly lower compared to controls, and the histology of the ovaries of the treated rats displayed severely atretic large antral follicles. There was almost no viral labeling in the central nervous system from the ovaries showing precystic morphology, in spite of the fact that such altered organs are rich in nerve fibres. It is assumed that presently unidentified factors in the precystic ovary, presumably related to the link between the immune and the nervous system, might be involved in the infectivity of the virus, and thus be responsible for the lack of viral labeling from such an ovary.     

Study of the interface in Kevlar 49-epoxy composites by means of microbond and fragmentation tests: effects of materials and testing variables

The work presented in the present paper focuses on the interface in Kevlar 49-epoxy composites. Experimental results for the interfacial shear strength obtained using the microbond test by means of different loading configurations (parallel plate loading, parallel conical plate loading, circular loading), are presented and compared. Contrasting with recent finite-element predictions proposed in the literature, the interfacial shear strength is found to be altogether insensitive to the type of microbond loading configuration. A comparison of the results obtained using two micromechanical tests (microbond and fragmentation) is performed. The interfacial shear strength results obtained by means of the fragmentation test are found to be higher by a factor of about 50% than those obtained by means of the microbond test. A possible explanation for this difference is proposed and discussed, and the value of the true interfacial shear strength is conjectured to fall between the values measured by these two tests. The effect of fibre surface chemistry modification (surface desizing) is probed by surface-sensitive techniques (XPS-ESCA and contact angle measurements from droplets) and by micromechanical testing techniques. Surface-sensitive techniques and micromechanical testing provide compatible information for the Kevlar-epoxy system studied here, and the knowledge of the chemical characteristics of the fibre surface can therefore be used as a means of predicting the interfacial shear strength.     

Interfacial load transfer in carbon nanotube/ceramic microfiber hybrid polymer composites

Growing carbon nanotubes (CNTs) on the surface of fibers has the potential to modify fiber–matrix interfacial adhesion, enhance the composite delamination resistance, and possibly improve its toughness and any matrix-dominated elastic property as well. In the present work aligned CNTs were grown upon ceramic fibers (silica and alumina) by chemical vapor deposition (CVD) at temperatures of 650 °C and 750 °C. Continuously-monitored single fiber composite (SFC) fragmentation tests were performed on pristine as well as on CNT-grown fibers embedded in epoxy. The critical fragment length, fiber tensile strength at critical length, and interfacial shear strength were evaluated. Significant increases (up to 50%) are observed in the fiber tensile strength and in the interfacial adhesion (which was sometimes doubled) with all fiber types upon which CNTs are CVD-grown at 750 °C. We discuss the likely sources of these improvements as well as their implications.     

Movement on Shifting Sands: Deinstitutionalisation and People with Intellectual Disability in Australia, 1974–2014

This article reviews four decades of deinstitutionalisation policies in three Australian states, New South Wales, Victoria and Queensland. It seeks to understand the factors influencing the slow and haphazard progression of the movement and its more contested outcomes such as the redevelopment of some institutions and their replacement with other congregate or cluster housing models that are at odds with the original visions of community care and normalisation. The article highlights the consistent and effective opposition to deinstitutionalisation from some families of institution residents, and the shifting policy frameworks and ideologies—from ‘normalisation’ to ‘choice’—in which it progressed. In particular, the article highlights the intersections between deinstitutionalisation and urban policy. The article is based on a review of existing scholarly literature, policy documents, inquiry reports and media sources.     

Exploration of Routes Leading to Derivatives of α-Hydroxyalanine and its Precursors

The preparation of fully protected derivatives of DL-α-hydroxyalanine is described. Several possible routes leading to protected DL-α-hydroxyalanine and α-hydroxyglycine were explored. Attempts to remove the protecting groups led in most cases to the disruption of the molecule. The N-carboxyanhydride of O-benzyl-DL-α-hydroxyalanine was prepared and trimerised to give dehydroalanyl-O-benzyl-DL-α-hydroxyalanyldehydroalanine. This is a novel type of polymerization of N-carboxyanhydrides concurrent with elimination of benzyl alcohol. A generally useful method of purification of oily half esters of dicarboxylic acids through their crystalline dibenzylamine salts has been developed.     

Mode of termination of retinotectal fibers in macaque monkey: an autoradiographic study

The distribution of retinotectal projections was studied in 4 macaque monkeys by examining the tectum autoradiographically 3-21 days after eye injection with radioactive proline or a proline-fucose mixture. Contrary to previous reports the optic fibers project to all regions of the tectum including a relatively sparse but nevertheless very clear projection to the anterolateral one-third, where the fovea is represented. Here the terminals were distributed within the superficial grey layer of the tectum at a depth extending from about 50 mum to 125 mum and in a patchy fashion, with a tendency to aggregation in clumps 0.1-0.5 mm wide from one or other eye. Further posteromedially, corresponding to more peripheral retinal regions, the input from the contralateral eye became more continuous superficially, with tongues extending more deeply in the superficial grey, apparently enclosing clumps of ipsilateral terminals. These deeper ipsilateral clumps occupied a rather well defined layer extending in depth from about 100 mum to about 175 mum. Still further posteromedially, in the temporal crescent representation, only the continuously distributed label from the contralateral eye was found. Continuous label was also seen in the optic disc region on the ipsilateral side; on the corresponding area contralaterally, label was absent. Both ipsilaterally and contralaterally, the pattern of input was roughly symmetrical about the representation of the horizontal meridian, which ran from anterolateral to posteromedial. The regional aggregations of input from one or other eye were to some extent reflected physiologically in a regional variation in eye dominance, though this was perhaps less than might have been expected from the marked heterogeneity of the inputs.     

A new recombinant procoagulant protein derived from the cDNA encoding human factor VIII

We have constructed new B domain deletion derivatives of humanfactor Vm (FVm) by manipulating the cDNA using recombinant DNAtechniques. One of these new derivatives, FVIII II, in whichamino acids 771(pro)–1666(asp) have been deleted, no longercontains the protease cleavage site at amino acid position 1648(arg)–1649(glu) known to be involved in the initial step ofFVin processing. We have expressed this molecule in both babyhamster kidney (BHK) 21 cells using the vaccinia virus (VV)expression system and have established Chinese hamster ovary(CHO) derived permanent cell lines expressing either recombinant(r)FVIII or FVIII II AD. The characteristics of FVIII II ADhave been compared to those of rFVIII and/or plasma derived(pd) FVIII. FVIII II All has the following properties: (i) itexhibits FVDI procoagulant activity; (ii) it is expressed at5-fold higher levels than is the complete molecule in comparablesystems; (iii) it migrates for the most part as a single majorband on SDS-PAGE, hi contrast to the complete molecule; (iv)it is activated to a greater extent by thrombin than is eitherrFVm or pdFVIII; and (v) it retains the ability to bind vonWillebrand factor (vWf).