Multigrid preconditioned conjugate-gradient method for large-scale wave-front reconstruction

We introduce a multigrid preconditioned conjugate-gradient (MGCG) iterative scheme for computing open-loop wave-front reconstructors for extreme adaptive optics systems. We present numerical simulations for a 17-m class telescope with n = 48756 sensor measurement grid points within the aperture, which indicate that our MGCG method has a rapid convergence rate for a wide range of subaperture average slope measurement signal-to-noise ratios. The total computational cost is of order n log n. Hence our scheme provides for fast wave-front simulation and control in large-scale adaptive optics systems.     

AM noise impact on low level phase noise measurements

The influence of the source AM noise in microwave residual phase noise experiments is investigated. The noise floor degradation problem, caused by the parasitic detection of this type of noise by an imperfectly balanced mixer, is solved thanks to a refinement of the quadrature condition. The parasitic noise contribution attributable to the AM to PM (phase modulation) conversion occurring in the device under test is minimized through the development of a dedicated microwave source featuring an AM noise level as low as -170 dBc/Hz at 10 kHz offset from a 3.5 GHz carrier     

Multiple-scattering lidar retrieval method: tests on Monte Carlo simulations and comparisons with in situ measurements

A multiple-field-of-view (MFOV) lidar measurement and solution technique has been developed to exploit the retrievable particle extinction and size information contained in the multiple-scattering contributions to aerosol lidar returns. We describe the proposed solution algorithm. The primary retrieved parameters are the extinction coefficient at the lidar wavelength and the effective particle diameter from which secondary products such as the extinction at other wavelengths and the liquid-water content (LWC) of liquid-phase clouds can be derived. The solutions are compared with true values in a series of Monte Carlo simulations and with in-cloud measurements. Good agreement is obtained for the simulations. For the field experiment, the retrieved effective droplet diameter and LWC for the available seven cases studied are on average 15% and 35% (worst case) smaller than the measured data, respectively. In the latter case, the analysis shows that the differences cannot be attributed solely to lidar inversion errors. Despite the limited penetration depth (150-300 m) of the lidar pulses, the results of the studied cases indicate that the retrieved lidar solutions remain statistically representative of measurements performed over the full cloud extent. Long-term MFOV lidar monitoring could thus become a practical and economical option for cloud statistical studies but more experimentation on more varied cloud conditions, especially for LWC, is still needed.     

An improved observation model for super-resolution under affine motion.

Super-resolution (SR) techniques make use of subpixel shifts between frames in an image sequence to yield higher resolution images. We propose an original observation model devoted to the case of nonisometric inter-frame motion as required, for instance, in the context of airborne imaging sensors. First, we describe how the main observation models used in the SR literature deal with motion, and we explain why they are not suited for nonisometric motion. Then, we propose an extension of the observation model by Elad and Feuer adapted to affine motion. This model is based on a decomposition of affine transforms into successive shear transforms, each one efficiently implemented by row-by-row or column-by-column one-dimensional affine transforms. We demonstrate on synthetic and real sequences that our observation model incorporated in a SR reconstruction technique leads to better results in the case of variable scale motions and it provides equivalent results in the case of isometric motions.     

A Cost-Regular Based Hybrid Column Generation Approach

Constraint Programming (CP) offers a rich modeling language of constraints embedding efficient algorithms to handle complex and heterogeneous combinatorial problems. To solve hard combinatorial optimization problems using CP alone or hybrid CP-ILP decomposition methods, costs also have to be taken into account within the propagation process. Optimization constraints, with their cost-based filtering algorithms, aim to apply inference based on optimality rather than feasibility. This paper introduces a new optimization constraint, cost-regular. Its filtering algorithm is based on the computation of shortest and longest paths in a layered directed graph. The support information is also used to guide the search for solutions. We believe this constraint to be particularly useful in modeling and solving Column Generation subproblems and evaluate its behaviour on complex Employee Timetabling Problems through a flexible CP-based column generation approach. Computational results on generated benchmark sets and on a complex real-world instance are given.A preliminary version of this paper appeared as [7]. This research was supported by the Mathematics of Information Technology and Complex Systems (MITACS) Internship program in association with Omega Optimisation Inc. (CA).     

The effect of converting from pravastatin to simvastatin on the pharmacodynamics of warfarin

Glycosylated amino acids and glycosylated human serum albumin reduce nitrite to nitric oxide under anaerobic conditions. The amount of nitric oxide produced was recorded by generation of nitrosoHb from deoxyHb. Without preincubation after the addition of sodium nitrite, glucose or a mixture of glucose with amino acid or serum albumin did not cause spectrophotometrically detectible transformation of deoxyHb into nitrosoHb. The generation of NO increased with an increase in content of colored "final" products of amino acid and serum albumin glycosylation in the incubation mixture. The incubation of blood plasma of patients with diabetes mellitus with nitrite also resulted in the increased production of NO as compared to blood plasma of healthy subjects. During the incubation of healthy subjects' blood plasma with nitrite a small amount of NO was produced. The removal of low-molecular-weight compounds was accompanied by a significantly decreased generation of NO by blood plasma.     

Randomized controlled trial of effects of Escherichia coli antiserum on serum immunoglobulin G concentrations and morbidity and mortality rates in foals

OBJECTIVE: To determine whether administration of commercially available Escherichia coli antiserum to neonatal foals would affect serum IgG concentration or morbidity and mortality rates during the first 60 days of life. DESIGN: Randomized controlled trial. ANIMALS: 271 neonatal foals on 4 well-managed farms. PROCEDURE: Foals were randomly assigned to a treatment or control group. All foals were allowed to suckle colostrum normally. In addition, treatment-group foals were given E coli antiserum (10 micromilligrams) orally between 0 and 8 hours after birth. Serum samples were obtained between 18 and 36 hours after birth, and serum IgG concentration was determined. Foals were monitored for the first 60 days after birth, and causes of disease or death were recorded. RESULTS: Groups did not differ significantly in regard to breed, sex, month of birth, season of birth, age of dams, parity of dams, duration of gestation, or specific gravity of colostrum before suckling. In addition, groups did not differ significantly in regard to mean serum IgG concentration, prevalence of complete or partial failure of passive transfer of immunity, frequency or causes of disease, or frequency of death from infectious causes. CLINICAL IMPLICATIONS: In this group of foals on well-managed farms, administration of E coli antiserum did not alter serum IgG concentrations or morbidity and mortality rates during the first 60 days of life.     

Prevalence and predictors of sexual dysfunction in long-term survivors of marrow transplantation

PURPOSE: To describe the prevalence of sexual difficulties in men and women after marrow transplantation (MT), and to define medical, demographic, sexual, and psychologic predictors of sexual dysfunction 3 years after MT. PATIENTS AND METHODS: Four hundred seven adult MT patients were assessed pretransplantation. Survivors repeated measures of psychologic and sexual functioning at 1 and 3 years posttransplantation. RESULTS: Data were analyzed from 102 event-free 3-year survivors who defined themselves as sexually active. Men and women did not differ in sexual satisfaction pretransplantation. At 1 and 3 years posttransplantation, women reported significantly more sexual dysfunction than men. Eighty percent of women and 29% of men reported at least one sexual problem by 3 years after MT. No pretransplantation variables were significant predictors of 3-year sexual satisfaction for women. For men, pretransplantation variables of older age, poorer psychologic function, not being married, and lower sexual satisfaction predicted sexual dissatisfaction at 3 years (R2=.28; P < .001). Women who were more dissatisfied 3 years after MT did not receive hormone replacement therapy (HRT) at 1 -year posttransplantation and were less satisfied at 1 year, but not pretransplantation (R2=.35; P < .001). CONCLUSION: Sexual problems are significant in the lives of MT survivors, particularly for women. Although HRT before 1 year posttransplantation improves sexual function, it does not ensure sexual quality of life. Intervention for women is needed to apply hormonal, mechanical, and behavioral methods to prevent sexual difficulties as early after transplantation as possible.     

Visual selective attention after severe closed head injury

This study investigated the nature of selective attention deficits after severe closed head injury (CHI). Twenty participants with severe CHI (greater than 1 year postinjury) and 20 matched controls completed search and nonsearch visual selective attention tasks under conditions of low (Experiment 1) and high (Experiment 2) target-distractor similarity. In the search situations, participants searched visual displays that contained 1, 4, or 8 items for the targets. In the nonsearch situations, the location of the targets was visually cued with a peripheral arrow. The results revealed that in both the low and high target-distractor similarity search conditions. CHI participants required a longer time than controls to locate and identify the target. In contrast, in the nonsearch condition, CHI participants were able to successfully ignore irrelevant task information when target-distractor similarity was low. However, when target-distractor similarity was high, CHI participants had more difficulty than controls ignoring the irrelevant information. These results suggest that, in comparison to controls, CHI participants may be at a disadvantage in selective attention situations when visual search is required and when the discriminability between targets and distractors is difficult.     

Multiple sclerosis: in situ evidence for antibody- and complement-mediated demyelination

Blue light responses in higher plants can be mediated not only by specific blue light receptors, but also by the red/far-red photoreversible phytochrome system. The question of interdependence between these photoreceptors has been debated over many years. The availability of Arabidopsis mutants for the blue light receptor CRY1 and for the two major phytochromes phyA and phyB allows a reinvestigation of this question. The analysis of photocontrol of seed germination, inhibition of hypocotyl growth and anthocyanin accumulation clearly demonstrates that (i) phyA shows a strong control in blue light responses especially at low fluence rates; (ii) phyB mediated induction reactions can be reversed by subsequent blue light irradiations; and (iii) CRY1 mediates blue light controlled inhibition of hypocotyl growth only at fluence rates higher than 5 mumol m-2s-1 and independently of phytochrome A and B.