Necessary conditions for asymptotic tracking in nonlinear systems

In the literature, it has been shown that if a single-input single-output analytic nonlinear plant 1) has a well-defined relative degree and 2) is minimum-phase, it is possible to achieve asymptotic tracking for an open set of output trajectories containing the origin in C^N [0, ∞), the space of N-times continuously differentiable functions taking values in R. When either of these sufficient conditions is not met, various authors have investigated approximate analytic solutions, discontinuous solutions and solutions for restricted sets of trajectories. In this paper, it is shown that conditions 1) and 2) are necessary for the existence of an analytic compensator which yields asymptotic tracking for an open set of output trajectories. Analogous results are established for multi-input multi-output systems     

In search of a dose-response relationship with radiotherapy in the management of recurrent rectal carcinoma in the pelvis: a systematic review

BACKGROUND: Research on the subject of insight has been hampered by difficulties in definition and reliable measurement. METHODS: We compared several rating scales to measure insight on a group of 33 psychotic patients as well as assessing patients' psychopathology, clinical characteristics and cognitive functioning. RESULTS: Most currently used scales showed a high degree of inter-correlation. Measures of insight related strongly to the presence of delusions; grandiosity (inversely), and depression (positively). Higher insight scores correlated with indices of treatment compliance and inversely with substance abuse. Measures of pre-morbid IQ and impaired executive functioning, including the Wisconsin Card Sorting Test were not associated with poor insight. CONCLUSIONS: The study highlights aspects of psychopathology and clinical variables particularly related to insight and supports the continued use of standardized scales in further research in this area.     

cDNA sequence and gene locus of the human retinal phosphoinositide-specific phospholipase-C beta 4 (PLCB4)

Defects in the Drosophila norpA (no receptor potential A) gene encoding a phosphoinositide-specific phospholipase C (PLC) block invertebrate phototransduction and lead to retinal degeneration. The mammalian homolog, PLCB4, is expressed in rat brain, bovine cerebellum, and the bovine retina in several splice variants. To determine a possible role of PLCB4 gene defects in human disease, we isolated several overlapping cDNA clones from a human retina library. The composite cDNA sequence predicts a human PLC beta 4 polypeptide of 1022 amino acid residues (MW 117,000). This PLC beta 4 variant lacks a 165-amino-acid N-terminal domain characteristic for the rat brain isoforms, but has a distinct putative exon 1 unique for human and bovine retina isoforms. A PLC beta 4 monospecific antibody detected a major (130 kDa) and a minor (160 kDa) isoform in retina homogenates. Somatic cell hybrids and deletion panels were used to localize the PCLB4 gene to the short arm of chromosome 20. The gene was further sublocalized to 20p12 by fluorescence in situ hybridization.     

Application of the Taguchi Method to the Optimization of the Submerged Arc Welding Process

Application of the Taguchi method to the optimization of the submerged arc welding process is reported. The Taguchi method is used to formulate the experimental layout, to analyze the effect of each welding parameter on welding performance, and to predict the optimal setting for each welding parameter. Experimental results are provided to confirm the effectiveness of this approach.     

Beta-blocker therapy of severe congestive heart failure in infants with left to right shunts

We report on the clinical and neurohumoral effects of adding low-dose propranolol to conventional therapy with digoxin and diuretics in 6 infants with severe congestive heart failure due to large left-to-right shunts. A significant decrease in heart failure scores and a decrease of the highly activated renin-angiotensin-1 aldosterone system by approximately 70% strongly suggests a beneficial effect of this new therapeutic approach.     

Receptor-like protein tyrosine phosphatases: alike and yet so different

Reversible phosphorylation on tyrosine residues is an extremely rapid and powerful posttranslational modification that is used in signalling pathways for the regulation of cell growth and differentiation. Over the past several years an impressive number of receptor-like protein tyrosine phosphatase (RPTPase) family members have been identified by molecular cloning, and undoubtedly many more will follow. This review provides an overview of the molecular data that are available for the currently identified RPTPases and discusses their possible biological implications.