Causal and Stable Input/Output Structures on Multidimensional Behaviours

In this work we study multidimensional (nD) linear differential behaviours with a distinguished independent variable called "time". We define in a natural way causality and stability on input/output structures with respect to this distinguished direction. We make an extension of some results in the theory of partial differential equations, demonstrating that causality is equivalent to a property of the transfer matrix which is essentially hyperbolicity of the Pc operator defining the behaviour (Bc)0,y We also quote results which in effect characterise time autonomy for the general systems case. Stability is likewise characterized by a property of the transfer matrix. We prove this result for the 2D case and for the case of a single equation; for the general case it requires solution of an open problem concerning the geometry of a particular set in Cn. In order to characterize input/output stability we also develop new results on inclusions of kernels, freeness of variables, and closure with respect to S,S' and associated spaces, which are of independent interest. We also discuss stability of autonomous behaviours, which we beleive to be governed by a corresponding condition

Pilot study on virtual imaging for patient information on radiotherapy planning and delivery

It is widely accepted that health professionals might sometimes underestimate cancer patients' needs for information on the complex process of radiotherapy (RT) planning and delivery. Furthermore, relatives might also feel excluded from the treatment of their loved ones. This pilot study was carried out in order to assess whether both patients and their relatives would welcome further information on RT planning and delivery using the virtual reality (VR) system VERT. One hundred and fifty patients with different types of cancer receiving radical RT were included in the study. Patients and relatives were shown using VERT on a one-to-one basis with an oncologist or a radiographer, a standard room where RT is given, a linear accelerator, and how RT is planned and delivered using their own planning CT Scans. Patients welcomed this information as it helped them to reduce their fears about RT. Relatives felt also more involved in the treatment of their loved one. The results obtained in this pilot study show that VR aids could become an important tool for delivering information on RT to both patients and relatives

Electron Transfer from Azide Radical to Histidine Generates Histidinyl Radical

The formation of histidinyl radical (HR), which is a product of electron transfer reaction between histidine and some free radicals, was studied by pulse radiolysis. The reaction between histidine and azide radicals was found to produce HR, which has a distinct absorption spectrum with peaks at 300, 480 and 520 nm. The formation of HR was found to depend solely on the concentration of azide radicals, with the first order rate of 1.46 x 104 s-1. The implication of the formation of HR in an enzyme, which has histidine as the crucial amino acid to its activity, is discussed.Keywords: Histidine, Histidinyl radical, Azide radical

Characteristics of Separated Flow Regions Within Altitude Compensating Nozzles Final Report

Characteristics of separated flow regions within altitude compensating nozzle

Functions preserving nonnegativity of matrices

The main goal of this work is to determine which entire functions preserve nonnegativity of matrices of a fixed order $n$ -- i.e., to characterize entire functions $f$ with the property that $f(A)$ is entrywise nonnegative for every entrywise nonnegative matrix $A$ of size $n\times n$. Towards this goal, we present a complete characterization of functions preserving nonnegativity of (block) upper-triangular matrices and those preserving nonnegativity of circulant matrices. We also derive necessary conditions and sufficient conditions for entire functions that preserve nonnegativity of symmetric matrices. We also show that some of these latter conditions characterize the even or odd functions that preserve nonnegativity of symmetric matrices.Comment: 20 pages; expanded and corrected to reflect referees' remarks; to appear in SIAM J. Matrix Anal. App

Comparison of first parturition outcome between mothers aged 15-19 and 20-24 years

Context: Comparative data on pregnancy, labour and delivery outcomes of nulliparae aged 15-19 and 20-24 years are limited.Objectives: To compare the pregnancy, labour and delivery outcomes of nulliparae aged 15-19 and 20-24 years.Study Design, Settings and Subjects: A retrospective comparative study conducted at Olabisi Onabanjo University Teaching Hospital, Sagamu, Nigeria. Nulliparae aged 15-19 years (study group) and 20-24 years (control group) were compared with respect to height, haematocrit levels at booking and 48 hours after delivery, mode of delivery, birth weight, and antenatal, intrapartum and postpartum complications.Results: The study group booked with significantly lower haematocrit (p<0.002) and had a significant drop in the haematocrit level after delivery (p<0.001) than the control group. There were no significant differences between the two groups with respect to maternal height, birth weight, mode of delivery and Apgar scores at one and five minutes. The frequency of prolonged labour from cephalo-pelvic disproportion was similar between the study and control groups.Conclusion: There were not much differences in the obstetric performance of the two groups presumably because the bulk of the study group were aged 18 and 19 years when the pelvis had attained maximum growth as in the control group

Characterization of Agrobacterium tumefaciens strains isolated from grapevine

Grapevine crown gall is predominantly induced by Agrobacterium vitis, but rarely, Agrobacterium tumefaciens may also cause this disease. We have collected 18 grapevine isolates of A. tumefaciens from distinct geographical regions and various grapevine varieties. Characterization of these strains showed that 7 of the 18 strains carried A. vitis-type octopine/cucumopine Ti plasmids, utilized tartrate, were avirulent on pea and did not respond to the virC-specific PCR primers like A. vitis. Eleven of the 18 strains carried A. tumefaciens-type Ti plasmids, did not grow on tartrate, were virulent on pea and reacted positively to virC-specific PCR primers. Two of these strains induced octopine/agropine-, and two strains induced agropine producing tumors on grapevine and/or Kalanchoe tubiflora plants. The remaining 7 strains showed the characteristic properties of A. tumefaciens nopaline strains and were sensitive to agrocin 84