Digital correlation for noise radar systems

A recently developed radar system using a c.w. microwave noise spectrum from an impatt oscillator as the transmitted signal has shown useful performance. The application of a digital correlator to measure, essentially in real time, the autocorrelation function of the noise spectrum and provide a radar display of targets at ranges of up to at least 1 km is now described.     

The empirical investigation of Perspective-Based Reading

We consider reading techniques a fundamental means of achieving high quality software. Due to the lack of research in this area, we are experimenting with the application and comparison of various reading techniques. This paper deals with our experiences with a family of reading techniques known as Perspective-Based Reading (PBR), and its application to requirements documents. The goal of PBR is to provide operational scenarios where members of a review team read a document from a particular perspective, e.g., tester, developer, user. Our assumption is that the combination of different perspectives provides better coverage of the document, i.e., uncovers a wider range of defects, than the same number of readers using their usual technique.To test the effectiveness of PBR, we conducted a controlled experiment with professional software developers from the National Aeronautics and Space Administration/Goddard Space Flight Center (NASA/GSFC) Software Engineering Laboratory (SEL). The subjects read two types of documents, one generic in nature and the other from the NASA domain, using two reading techniques, a PBR technique and their usual technique. The results from these experiments, as well as the experimental design, are presented and analyzed. Teams applying PBR are shown to achieve significantly better coverage of documents than teams that do not apply PBR.We thoroughly discuss the threats to validity so that external replications can benefit from the lessons learned and improve the experimental design if the constraints are different from those posed by subjects borrowed from a development organization.     

Tertiary treatment of municipal wastewater by cypress domes

The feasibility of using cypress domes as an alternative to physical-chemical methods for tertiary treatment of sewage effluent was demonstrated over a 5-year period. Surface water quality in domes receiving effluent was degraded (low dissolved oxygen, high nutrient levels) compared to control domes, and the degree of treatment within the dome surface waters was relatively small. However, water samples from shallow wells and ceramic soil moisture tubes indicated that the underlying organic soils and clay sands served as an effective barrier to the transport of biochemical oxygen demand, nitrogen, phosphorus, sulfate, fluoride, potassium, sodium, calcium, and magnesium to the shallow aquifer immediately below. High percentage removals were observed for all measured water quality parameters between the surface and groundwater stations. Standing water quality following the cessation of sewage pumping did not return to the same quality as found for the natural dome within 20 months.     

Initial observations of optical injection locking of an X-band Impatt oscillator

An experiment is described in which the output of a GaAlAs laser, modulated at 2.6 GHz, was used to optically sub-harmonic injection lock a 7.8 GHz Impatt oscillator. A locking range of 1 MHz was achieved and means are suggested by which this may be increased substantially.     

Arylsulfonate esters of fatty alcohols as hypocholesterolemic agents. I: Oleyl and linoleyl p-toluenesulfonates

Cholesterol levels of both plasma and liver of cholesterol-fed rats are lowered by feeding linoleyl and oleyl esters of p-toluenesulfonic acid. A structural specificity exists, since the effect is not observed with similar amounts of sodium p-toluenesulfonate nor with linoleyl methanesulfonate. Effective levels of these arylsulfonates do not alter liver to body weight ratios and maturation, nor reduce plasma cholesterol in normocholesterolemic rats. Published as Journal Paper No. 6696, AES, Purdue University     

The separation of zinc from copper by di-2-ethylhexyl phosphoric acid - an equilibrium study

The extraction of copper and zinc from sulphate media by di-2-ethylhexylphosphoric acid (D2EHPA) is reported. The equilibrium data for the extraction of (1) zinc alone (2–40 g/l), and (2) copper alone (2–60 g/l) by both 10 v/v % and 20 v/v % D2EHPA are given.The general case of extraction of two metals which compete for the same extractant is considered, and the data for the binary metal system zinc/copper extracted by 20 v/v % D2EHPA are reported. Specific chemical models and empirical models have been developed to correlate the data.Because the extractant has a high affinity for zinc in the presence of copper, the binary data can be modelled on the assumption that the interaction of copper with zinc can be neglected. However, the effect of zinc in reducing the extraction of copper is significant.We show that zinc can be decontaminated from copper and test the predictions with a laboratory scale counter current apparatus. Typical predictions show that in five stages, a 20 v/v % D2EHPA feed and an aqueous feed of 1.98 g/l Zn, 36.78 g/l Cu, zero g/l H₂SO₄ would give a 89.9% recovery of zinc with purity of 90%; with lower copper to zinc ratios in the feed the purity may be improved.     

Continuity of care and delivery of ambulatory services to children in community health clinics

This study assesses how continuity of care influences receipt of preventive care and overall levels of ambulatory care among children and adolescents in community health clinics (CHCs). It is a secondary data analysis of the 1988 Child Health Supplement to the National Health Interview Survey. Of 17,110 children in the sample population, the 1465 who identified CHCs as their routine source of care formed the study population. Continuity of site was defined as identification of a CHC as a source of both routine and sick care, and continuity with a clinician was defined as identification of a specific clinician for sick visits. In bivariate analyses both continuity with the CHC and with a specific clinician were associated with increased levels of preventive care and overall ambulatory care. In logistic regression models, continuity of care was associated with nearly a two-fold increase in the odds of receiving age-appropriate preventive care. Alternatively, insurance status was a better predictor of receipt of overall levels of ambulatory care. We conclude that expanding financial access alone is unlikely to sufficiently improve low-income children's access to Community Health Clinics. Additional emphasis on localizing the delivery of both routine and sick care services in a single site or with a specific clinician may be needed to achieve higher levels of both preventive care and overall ambulatory care.     

Efficacy of self-examination therapy in the treatment of generalized anxiety disorder.

To determine the efficacy of self-examination therapy in the treatment of generalized anxiety disorder, 38 adults volunteered for a study in which they were randomly assigned to self-examination therapy or to a delayed-treatment group. Analyses indicated that participants in self-examination therapy had significantly fewer symptoms of anxiety than did participants in the delayed-treatment group on the outcome measures of this study, which included ratings by trained clinicians and participants. The reduction in anxiety for people receiving self-examination therapy was maintained 3 months after treatment ended. The delayed-treatment group also showed significant improvement in anxiety symptoms after receiving self-examination therapy. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Commercial satellite broadcasting for Europe

A review is presented of the current television broadcasting situation in European countries, which involves a varied mix of terrestrial VHF or UHF systems and cable networks. A small market has emerged in Europe for receivers using the low-power telecommunications satellite transmission between the program providers and cable network companies. This is expected to change with the launch of medium-power pan-European telecommunication satellites (e.g. ASTRA, EUTELSAT II), which are now directly addressing the market of home reception. DBS (direct broadcast satellite) in the UK, using the D-MAC transmission standard, will offer three additional television channels, data broadcasting services, and a planned evolution to compatible forms of wide-screen, high-definition television. Comments are given on receiver and conditional access system standardization. Some views are expressed on satellite broadcasting as part of an overall broadcasting framework for the future