Investigation of image enhancement techniques for the development of a self-contained airborne radar navigation system

This study was devoted to an investigation of the feasibility of applying advanced image processing techniques to enhance radar image characteristics that are pertinent to the pilot's navigation and guidance task. Millimeter (95 GHz) wave radar images for the overwater (i.e., offshore oil rigs) and overland (Heliport) scenario were used as a data base. The purpose of the study was to determine the applicability of image enhancement and scene analysis algorithms to detect and improve target characteristics (i.e., manmade objects such as buildings, parking lots, cars, roads, helicopters, towers, landing pads, etc.) that would be helpful to the pilot in determining his own position/orientation with respect to the outside world and assist him in the navigation task. Results of this study show that significant improvements in the raw radar image may be obtained using two dimensional image processing algorithms. In the overwater case, it is possible to remove the ocean clutter by thresholding the image data, and furthermore to extract the target boundary as well as the tower and catwalk locations using noise cleaning (e.g., median filter) and edge detection (e.g., Sobel operator) algorithms

Sensitivity analysis of helicopter IMC decelerating steep approach and landing performance to navigation system parameters

Results of a study to investigate, by means of a computer simulation, the performance sensitivity of helicopter IMC DSAL operations as a function of navigation system parameters are presented. A mathematical model representing generically a navigation system is formulated. The scenario simulated consists of a straight in helicopter approach to landing along a 6 deg glideslope. The deceleration magnitude chosen is 03g. The navigation model parameters are varied and the statistics of the total system errors (TSE) computed. These statistics are used to determine the critical navigation system parameters that affect the performance of the closed-loop navigation, guidance and control system of a UH-1H helicopter

VTOL shipboard letdown guidance system analysis

Alternative letdown guidance strategies are examined for landing of a VTOL aircraft onboard a small aviation ship under adverse environmental conditions. Off line computer simulation of shipboard landing task is utilized for assessing the relative merits of the proposed guidance schemes. The touchdown performance of a nominal constant rate of descent (CROD) letdown strategy serves as a benchmark for ranking the performance of the alternative letdown schemes. Analysis of ship motion time histories indicates the existence of an alternating sequence of quiescent and rough motions called lulls and swells. A real time algorithms lull/swell classification based upon ship motion pattern features is developed. The classification algorithm is used to command a go/no go signal to indicate the initiation and termination of an acceptable landing window. Simulation results show that such a go/no go pattern based letdown guidance strategy improves touchdown performance

Modeling methodology for MLS range navigation system errors using flight test data

Flight test data was used to develop a methodology for modeling MLS range navigation system errors. The data used corresponded to the constant velocity and glideslope approach segment of a helicopter landing trajectory. The MLS range measurement was assumed to consist of low frequency and random high frequency components. The random high frequency component was extracted from the MLS range measurements. This was done by appropriate filtering of the range residual generated from a linearization of the range profile for the final approach segment. This range navigation system error was then modeled as an autoregressive moving average (ARMA) process. Maximum likelihood techniques were used to identify the parameters of the ARMA process

Antibody Response to Shiga Toxins in Argentinean Children with Enteropathic Hemolytic Uremic Syndrome at Acute and Long-Term Follow-Up Periods

Shiga toxin (Stx)-producing Escherichia coli (STEC) infection is associated with a broad spectrum of clinical manifestations that include diarrhea, hemorrhagic colitis, and hemolytic uremic syndrome (HUS). Systemic Stx toxemia is considered to be central to the genesis of HUS. Distinct methods have been used to evaluate anti-Stx response for immunodiagnostic or epidemiological analysis of HUS cases. The development of enzyme-linked immunosorbent assay (ELISA) and western blot (WB) assay to detect the presence of specific antibodies to Stx has introduced important advantages for serodiagnosis of HUS. However, application of these methods for seroepidemiological studies in Argentina has been limited. The aim of this work was to develop an ELISA to detect antibodies against the B subunit of Stx2, and a WB to evaluate antibodies against both subunits of Stx2 and Stx1, in order to analyze the pertinence and effectiveness of these techniques in the Argentinean population. We studied 72 normal healthy children (NHC) and 105 HUS patients of the urban pediatric population from the surrounding area of Buenos Aires city. Using the WB method we detected 67% of plasma from NHC reactive for Stx2, but only 8% for Stx1. These results are in agreement with the broad circulation of Stx2-expressing STEC in Argentina and the endemic behavior of HUS in this country. Moreover, the simultaneous evaluation by the two methods allowed us to differentiate acute HUS patients from NHC with a great specificity and accuracy, in order to confirm the HUS etiology when pathogenic bacteria were not isolated from stools

Perspectives and impact of a parent-child intervention on dietary intake and physical activity behaviours, parental motivation, and parental body composition: A randomized controlled trial

Adults and children in Canada are not meeting physical activity guidelines nor consuming sufficient nutrient-rich foods. High engagement in these unhealthy behaviours can lead to obesity and its associated diseases. Parent-child interventions aimed at obesity prevention/treatment have assisted families with making positive changes to their nutrition and physical activity behaviours. Given that the home environment shapes early health behaviours, it is important to target both parents and children when addressing diet and physical activity. One method that has been shown to improve health outcomes is co-active coaching. The current study explored the impact of a threemonth co-active coaching and/or health education intervention on the dietary intake and physical activity behaviours of parents with overweight/obesity and their children (ages 2.5–10; of any weight). Body composition (i.e., body mass index [BMI] and waist circumference), changes in parental motivation with respect to physical activity and dietary behaviours, and parental perceptions of program improvements were collected. A concurrent mixed methods study comprised of a randomized controlled trial and a descriptive qualitative design was utilized. Fifty parent-child dyads were recruited and randomly assigned to the control (n = 25) or intervention (n = 25) group. Assessments were completed at baseline, mid-intervention (six weeks), postintervention (three months), and six-month follow-up. A linear mixed effects model was utilized for quantitative analysis. Inductive content analysis was used to extract themes from parent interviews. No significant results were observed over time for the dependent measures. Parents in both control and intervention groups reported varied program experiences, including developing changes in perspective, increased awareness of habits, and heightened accountability for making positive changes in themselves, and consequently, their families. Parents also shared barriers they faced when implementing changes (e.g., time, weather, stress). Qualitatively, both groups reported benefitting from this program, with the intervention group describing salient benefits from engaging in coaching. This research expands on the utility of coaching as a method for behaviour change, when compared to education only, in parents with overweight/obesity and their children

Development of a biosensor for urea assay based on amidase inhibition, using an ion-selective electrode

A biosensor for urea has been developed based on the observation that urea is a powerful active-site inhibitor of amidase, which catalyzes the hydrolysis of amides such as acetamide to produce ammonia and the corresponding organic acid. Cell-free extract from Pseudomonas aeruginosa was the source of amidase (acylamide hydrolase, EC 3.5.1.4) which was immobilized on a polyethersulfone membrane in the presence of glutaraldehyde; anion-selective electrode for ammonium ions was used for biosensor development. Analysis of variance was used for optimization of the biosensorresponse and showed that 30 mu L of cell-free extract containing 7.47 mg protein mL(-1), 2 mu L of glutaraldehyde (5%, v/v) and 10 mu L of gelatin (15%, w/v) exhibited the highest response. Optimization of other parameters showed that pH 7.2 and 30 min incubation time were optimum for incubation ofmembranes in urea. The biosensor exhibited a linear response in the range of 4.0-10.0 mu M urea, a detection limit of 2.0 mu M for urea, a response timeof 20 s, a sensitivity of 58.245 % per mu M urea and a storage stability of over 4 months. It was successfully used for quantification of urea in samples such as wine and milk; recovery experiments were carried out which revealed an average substrate recovery of 94.9%. The urea analogs hydroxyurea, methylurea and thiourea inhibited amidase activity by about 90%, 10% and 0%, respectively, compared with urea inhibition

Preliminary Outcomes 1 Year after Laparoscopic Sleeve Gastrectomy Based on Bariatric Analysis and Reporting Outcome System (BAROS)

# The Author(s) 2011. This article is published with open access at Springerlink.com Background The aim of this study was to assess outcomes of laparoscopic sleeve gastrectomy (LSG) as a stand-alone bariatric operation according to the Bariatric Analysis and Reporting Outcome System (BAROS). Methods Out of 112 patients included and operated on initially, 84 patients (F/M, 63:21) were followed up for 14– 56 months (mean 22±6.75). Patients lost to follow-up did not attend scheduled follow-up visits or they have withdrawn their consent. Mean age was 39 years (range 17–67; SD±12.09) with mean initial BMI 44.62 kg/m 2 (range 29.39–82.8; SD±8.17). Statistical significance was established at the p<0.05 level. Results Mean operative time was 61 min (30–140 min) with mean hospital stay of 1.37 days (0–4; SD±0.77). Excellent global BAROS outcome was achieved in 13 % of patients, very good in 30%, good in 34.5%, fair 9.5 % and failure in 13 % patients 12 months after surgery. Females achieved significantly better outcomes than males with the mean 46.5 % of excess weight loss (EWL) versus 35.3 % of EWL at 12 months (p=0.02). The mean percentage of excess weight loss (%EWL) was 43.6 % at 12 months and 46.6 % at 24 months. Major surgical complication rate was 7.1%; minor surgical complication rate 8.3%. There was one conversion (1.2%) due to the massive bleeding. Comorbidities improved or resolved in numerous patients