Matched subspace detectors

We formulate a general class of problems for detecting subspace signals in subspace interference and broadband noise. We derive the generalized likelihood ratio (GLR) for each problem in the class. We then establish the invariances for the GLR and argue that these are the natural invariances for the problem. In each case, the GLR is a maximal invariant statistic, and the distribution of the maximal invariant statistic is monotone. This means that the GLR test (GLRT) is the uniformly most powerful invariant detector. We illustrate the utility of this finding by solving a number of problems for detecting subspace signals in subspace interference and broadband noise. In each case we give the distribution for the detector and compute performance curves     

Has the health profile and pregnant Ethiopian immigrants changed in the Ashkelon region in the past years?]

There are about 6500 births yearly in the Ashkelon District. 6% of the mothers are Ethiopians, most of whom immigrated to Israel since the early 90's. Our data are from 3 sources: birth certificates, infant death certificates, and the national population register. Birth rates in single mothers and rates of low-birth-weight births have declined over the years. Infant mortality and still-birth rates have also shown remarkable and consistent declines between 1990-1995. We conclude that improvement in life conditions of Ethiopian immigrants and better use of health services have had a great impact on birth outcomes and pregnancy patterns. The gap between Ethiopian immigrants and other Jewish communities in Israel is closing fast.     

Determination of heart time volume using the Fick principle in the early postoperative phase after correction of congenital heart defects. Comparison of the calculation of arterio-mixed venous oxygen differences and pulmonary oxygen uptake with the calculation of arterial-central venous oxygen differences and pulmonary oxygen uptake

Comparison of the calculation by means of the arterio-mixed venous oxygen difference and the oxygen uptake with the calculation by means of the arterio-central venous oxygen difference and the oxygen uptake. OBJECTIVE: How reliable is the measurement of cardiac output on Fick's principle without a pulmonary artery catheter? SETTING: PICU in an University hospital. DESIGN: In the postoperative period following complete repair of congenital heart disease we carried out 91 simultaneous measurements of blood gases in 45 infants and children (mean age 18.6 months, mean body weight 8.9 kg) from a systemic artery, the A. pulmonalis, and the V. cava superior. We also determined the pulmonary oxygen uptake in 24 patients (48 measurements). Cardiac output was calculated on Fick's principle using the arterio-mixed venous oxygen difference and the pulmonary oxygen uptake (HZV a-pa) and compared to the cardiac output derived from the central venous values (HZV a-zv). We differentiated between patients with a left to right shunt of 10% or more postoperatively (group A, n = 18) and all others (group B, n = 27). RESULTS: In both groups the correlation coefficient between HZV a-zv and HZV a-pa was high (group A: r = 0.97, group B: r = 0.94). In group A HZV a-pa (mean: 1958 ml/min) was higher than HZV a-zv (mean: 1340 ml/min), group B showed the opposite situation (mean HZV a-pa: 1136 ml/min, mean HZV a-zv: 1373 ml/min). With the Wilcoxon signet-rank test we found significant differences between the partial pressure of oxygen and the saturation of central venous and mixed venous blood samples in both groups, but HZV a-zv and HZV a-pa were different significantly on a level of p < or = 0.01 only in group A. CONCLUSIONS: In both groups HZV a-pa and HZV a-zv correlated well. Therefore, if a pulmonary artery catheter is not inserted; the course of the cardiac output can be calculated with acceptable reliability from the central venous blood gases. By means of Fick's principle the pulmonary blood flow is determined, which is higher than the systemic blood flow in cases of left to right shunting, because of the recirculation in the pulmonary blood circuit. Interpreting the results this has to be taken into account.     

Environmental risk assessment for quaternary ammonium compounds: a case study from Austria.

Quaternary ammonium compounds (QAC) are widely used as disinfectants, biocides, and detergents, among a variety of other applications. The cationic surface-activity of QAC determines their potential to act as a biocide on both target and non-target organisms. This study aims to provide a broad-based environmental risk characterization and evaluation for selected QAC with particular focus on the situation in Austrian rivers. A modular study design was employed involving environmental exposure characterization, QAC fate and effect analysis in wastewater, ecotoxicological effect characterization, and environmental risk evaluation. A wide array of Austrian surface waters and wastewater effluents were screened for the selected key compounds, benzalkonium chlorides and dialkyldimethylammonium chlorides with different C-chain lengths. Ecotoxicological effect characterization was based on both microbiotests for a set of representative aquatic organisms and a literature review. For risk evaluation, the PEC/PNEC ratio was above 1 for some rivers. Notably, small rivers with a high particulate matter were contaminated with QAC in the case of high water incidents. Hence, for the Austrian sites studied, a QAC-derived risk to sensitive aquatic non-target organisms could not be excluded.     

Determinants of young children's search strategies in a large-scale environment.

26 3–6 yr olds searched for an object after traveling a route along which the object was used and later discovered missing (critical events). Ss then recalled the order of locations along the traveled route (sequence recall) and the locations for critical events (event recall); they also drew a map of the search environment. The correlation between event recall and search scores was significant only for Ss with good sequence recall. Correlations between sequence recall and search scores were higher for Ss who placed locations on the route in drawing maps. It is concluded that the acquisition of route knowledge in the development of spatial representation determined the likelihood that inferences would be made. When inferences were made, the accuracy of memories for sequences and events further determined the accuracy of the inferred critical search area. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Longitudinal–differential phase distribution near the focus of a high numerical aperture lens: study of wavefront spacing and Gouy phase

The longitudinal–differential (LD) phase distribution was investigated near the focus of a high numerical aperture (NA = 0.9) aplanatic lens illuminated with a linearly polarized monochromatic plane wave. The Richards and Wolf method was used to compute field distributions. The LD phase map was obtained by analyzing the deviation of the phase of the simulated wave to the phase of a referential plane wave. The irregular wavefront spacing that is linked to the Guoy phase is discussed and subtle details of the phase features with respect to the spatial domain relative to the focal point are disclosed. The LD phase is used to revisit different definitions of the focal region. The definition is eventually identified that is in agreement with the Gouy phase in the focal region. Our work paves the way towards a coherent notion to quantify the optical action of high NA optical elements that are increasingly important for many applications.     

Magnesium secondary alloys: Alloy design for magnesium alloys with improved tolerance limits against impurities

The development of secondary magnesium alloys requires a completely different concept compared with standard alloys which obtain their corrosion resistance by reducing the levels of impurities below certain alloy and process depending limits. The present approach suitable for Mg-Al based cast and wrought alloys uses a new concept replacing the β-phase by τ-phase, which is able to incorporate more impurities while being electro-chemically less detrimental to the matrix. The overall experimental effort correlating composition, microstructure and corrosion resistance was reduced by using thermodynamic calculations to optimise the alloy composition. The outcome is a new, more impurity tolerant alloy class with a composition between the standard AZ and ZC systems having sufficient ductility and corrosion properties comparable to the high purity standard alloys.     

A telemetric pressure sensor system for biomedical applications

A new implantable pressure sensor for long-term monitoring of intracranial pressure is presented. The sensor is powered by telemetry and can be interrogated wirelessly. A capacitive pressure transducer, whose capacitance is converted to a frequency-encoded signal by an application-specific integrated circuit (ASIC), senses the absolute pressure. The pressure-encoded signal, the ASIC input voltage, and onboard calibration parameters are transmitted to an external reading unit. The proposed novel packaging solution is designed for long-term stability and reliability of the sensor. The accuracy of sensor at body temperature is better than 2 mbar across a pressure range of 600-1200 mbar. The sensor is 13 mm in diameter and 4.5 mm in height.     

Range sidelobes blanking by comparing outputs of contrasting mismatched filters

Range sidelobes, a major shortcoming of radar pulse compression, are often reduced through the use of mismatched filters. The authors propose to blank the remaining sidelobes by using two or more mismatched filters, whose sidelobes are designed to peak at different delays. The authors show how to design such filters and present promising simulation results with two or more mismatched filters.