The application of noncoherent Doppler data types for Deep Space Navigation

Recent improvements in computational capability and DSN technology have renewed interest in examining the possibility of using one-way Doppler data alone to navigate interplanetary spacecraft. The one-way data can be formulated as the standard differenced-count Doppler or as phase measurements, and the data can be received at a single station or differenced if obtained simultaneously at two stations. A covariance analysis, which analyzes the accuracy obtainable by combinations of one-way Doppler data, is performed and compared with similar results using standard two-way Doppler and range. The sample interplanetary trajectory used was that of the Mars Pathfinder mission to Mars. It is shown that differenced one-way data are capable of determining the angular position of the spacecraft to fairly high accuracy, but have relatively poor sensitivity to the range. When combined with single-station data, the position dispersions are roughly an order of magnitude larger in range and comparable in angular position as compared to dispersions obtained with standard two-way data types. It was also found that the phase formulation is less sensitive to data weight variations and data coverage than the differenced-count Doppler formulation

Validation of the Scale for the Assessment of Illness Behavior (SAIB) in a community sample of elderly people.

The aim of this study was to evaluate the construct validity of the SAIB in a community sample of elderly people. The SAIB was administered to a large community sample representative of the German population aged 60-85 years (n=1593). The original model was assessed and then refined through confirmatory and exploratory factor analyses. Criterion validity was evaluated by comparing SAIB scores with external criteria in 3 categories: subjective health, chronic illness and health care utilization. The originally suggested five factor structure of the SAIB yielded a comparative fit index (CFI) of 0.70 and the weighted root mean square residual (WRMR) was 3.68. A shortened questionnaire with 13 items and four factors resulted in better model fit (CFI 0.97 and WRMR 1.3). Correlations between subjective health and the new scales ranged from 0.06 to 0.33. Effect sizes (Cohens d) of mean differences in factor scores between those with and without healthcare system contact varied by healthcare type, ranging from 0.05 to 0.94; effect sizes were largest in relation to contact with psychotherapy and alternative medicine practitioners. We propose a shortened version of the SAIB with a different scale structure, which resulted in better model fit with our data. Neither the original nor revised SAIB appeared to discriminate well in terms of health care use, suggesting that the illness behavior as currently conceptualized may not fully explain the increased use of healthcare in the elderly

Comparative effectiveness of sitagliptin and vildagliptin in the management of patients with type 2 diabetes mellitus undergoing haemodialysis: an Indian rural tertiary care centre experience

Background: The prevalence of chronic kidney disease is increasing with diabetic nephropathy as the common underlying cause. Although numerous drugs are being used to improve glycaemic control, evidence in patients with diabetic nephropathy is sparse. The aim of the present was to evaluate the effectiveness of sitagliptin or vildagliptin addition on glycaemic control in patients with T2DM undergoing haemodialysis as part of their routine care in a rural tertiary care setting.Methods: Type 2 diabetic patients on maintenance haemodialysis as part of routine care and whose glycaemia was not controlled adequately and prescribed one of the oral gliptins once daily in addition to existing therapy for a period of 24 weeks were included in the present study. Effectiveness was assessed in terms of glycaemic control as measured by the change over time in glycated haemoglobin. Data analysis included glycated haemoglobin, body weight, serum creatinine, urine albumin creatinine ratio and the occurrence of hypoglycaemia.Results: Significant reduction in glycated haemoglobin values were noted after 24 weeks of therapy with gliptins similar to insulin glargine with a small weight loss. There was an insignificant decrease in the serum creatinine and urine albumin excretion levels after treatment with vildagliptin with Vildagliptin producing a slightly higher decrease but there was no correlation with changes in A1c levels. The overall incidence of adverse experiences was low and generally mild in both groups.Conclusions: In a group of Asian Indian patients with diabetic nephropathy due to T2DM undergoing haemodialysis in whom glycaemia was not controlled adequately, addition of gliptins helped to achieve glycaemic control to a similar extent as insulin glargine but with a marginal weight advantage

Accurate estimation of low [< (10^-8) ohm . cm²] values of specific contact resistivity

Advancements in nanotechnology have created the need for efficient means of communication of electrical signals to nanostructures, which can be addressed using low resistance contacts. In order to study and estimate the resistance of such contacts or the resistance posed by the interface(s) in such contacts, accurate test structures and evaluation techniques need to be used. The resistance posed by an interface is quantified using its specific contact resistivity (SCR), and although multiple techniques have been utilized, inaccuracies of such techniques in measuring values of SCR lesser than ( < 10-8 Ω ldr cm2 ) have been reported. In this letter, an approach for estimating very low values of SCR (lower than the previously limiting ( < 10-8 Ω ldr cm2 )) using a cross Kelvin resistor test structure is demonstrated using aluminum to titanium silicide ohmic contacts, with a minimum estimated SCR value of 6.0 times 10-10 Ω ldr cm2

RF magnetron sputtered perovskite-oriented PSZT thin films on gold for piezoelectric and ferroelectric transducers

Conditions for depositing perovskite-oriented Pb0.92Sr0.08(Zr0.65Ti0.35) O-3 thin films on gold by RF magnetron sputtering are investigated. Deposition results were analysed by scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffractometry. It was found that the desired perovskite phase can be obtained at a substrate temperature of 300 degrees C, much lower than the typically reported 650 degrees C for deposition on platinum