Optimal reconstruction of images from localized phase

The importance of localized phase in signal representation is investigated. The convergence rate of the POCS algorithm (projection onto convex sets) used for image reconstruction from spectral phase is defined and analyzed, and the characteristics of images optimally reconstructed from phase-only information are presented. It is concluded that images of geometric form are most efficiently reconstructed from their spectral phase, whereas images of symmetric form have the poorest convergence characteristics. The transition between the two extremes is shown to be continuous. The results provide a new approach and analysis of the previously reported advantages of the localized phase representation over the global approach, and suggest possible compression schemes.     

On the generalized likelihood ratio test for a class of nonlineardetection problems

The authors examine the generalized likelihood ratio test (GLRT) for a certain class of detection problems. This class is characterized by a model which is linear in some parameters and nonlinear in others. They show that the classical asymptotic analysis of the GLRT fails for this class, and demonstrate the existence of ill-behaved cases in this class. They then propose a modification of the GLRT. The main advantage of this modification is that its probability of false-alarm is easily computable, thus facilitating the choice of threshold according to the Neyman-Pearson criterion. Performance analysis of the modified GLRT is provided and supported by simulations     

Estimation of Pr{X>Y} or Pr{X⩽Y}

The paper presents a procedure for the estimation (point and interval) for a reliability model of the form Pr{X>Y} or Pr{X⩽Y} and Gaussian (normal) distributed variables. The procedures are derived from a quantitative approach that allows the user to get sufficient evidence, concerning the product reliability, by testing a small sample but at severe conditions, rather than testing a large sample at the nominal working conditions. Y has known parameters while X is a Gaussian r.v. with an unknown mean and a known coefficient-of-variation. The procedure is practical and cost effective when facing situations such as high test-cost, or severe contractual reliability requirements     

Need for Data Acquisition

Collecting and reporting of data have become increasingly complex tasks for the scientist. The search for the importance of interaction between disciplines has intensified the need for a standard of data collected and reported from experiments. The proposed standard is basic data and objective data. Basic data consist of the set of information that allows for repeatability of an experiment from one location to another, from year to year, and allows for comparison of one experiment with another. Basic data are 1) body weight, 2) physiological state of the animal, 3) diet, 4) health, 5) production, and 6) environment. The objective data will be the data set which allows the scientist to meet the particular objective of his experiment.     

Effects of prolonged social deprivation of murine behavior patterns, blood pressure, and adrenal weight.

Employed a behavioral monitoring technique using magnetic tagging for the prolonged observation of 6 colonies of control CBA mice (n = 102) and 3 colonies of CBA mice that were socially isolated for 6 mo (n = 51). After 40 days of social interacton in a population cage, several physiological and behavioral abnormalities were observed in the preisolated Ss. The males were hyperaggressive and failed to establish a stable social hierarchy, with a consequent high male mortality. Also, the preisolated Rank-1 males did not patrol their territory effectively in spite of greater overall activity. Phase drifts were found in both preisolated male and female circadian activity rhythms, together with elevated systolic blood pressures and adrenal weights. The females in the preisolated colonies had fewer pregnancies and an increased litter mortality compared with the control females. (20 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

SOME ASYMPTOTIC PROPERTIES OF THE SAMPLE COVARIANCES OF GAUSSIAN AUTOREGRESSIVE MOVING-AVERAGE PROCESSES

Abstract. The paper deals with the asymptotic variances of the sample covariances of autoregressive moving average processes. Using state-space representations and some matrix Lyapunov equation theory, closed-form expressions are derived for the asymptotic variances of the sample covariances and for the Cramer-Rao bounds on the process covariances. The main results obtained from these expressions are as follows: For ARMA ( p, q ) processes with p ≥ q , the sample covariance of order n is asymptotically efficient if and only if 0 ≤ n ≤ p – q .
For ARMA ( p, q ) processes with p < q , none of the sample covariances is asymptotically efficient.     

Diagnosing left lower lobe pneumonia: usefulness of the ''spine sign'' on lateral chest radiographs

Percutaneous cardiopulmonary assist devices (PCPS) have become available in interventional cardiology within recent years. These tools offer the opportunity of performing percutaneous transluminal coronary angioplasty (PTCA) in high-risk patients characterized by significant stenoses of several coronary arteries and a poor left ventricular function. It is unclear for which patients PCPS are necessary and which patients will profit by PTCA as compared to coronary artery bypass grafting (CABG). Therefore, the anticipated risk of CABG and of PTCA without assist devices was calculated according to risk scores and compared with our results of assisted PTCA. In addition the long-term survival rate was investigated. In 35 patients (mean 65.5 years of age, 12 females, 23 males), we performed PTCA concomitant with the use of cardiac assist devices. The indications for the use of a cardiac assist device were severely impaired LV function (EF 30% +/- 8.9%) in combination with significant coronary artery disease (2.7 +/- 0.3 vessels) and a significant supply area of the vessel to be dilated. In 6 patients, PCPS was started before coronary angioplasty because of hemodynamic instability. In 21 cases, PCPS was on a standby basis without being connected to the patient's circulation. In 8 patients, a left heart assist device, the 14F-Hemopump, was inserted percutaneously. The patients were analyzed using risk scores of angioplasty and of coronary bypass graft surgery. The calculated risk of hemodynamic compromise during PTCA according to the risk scores was more than 50%. The anticipated risk of a fatal outcome following CABG would have been 19.8%. PTCA was performed on an average of 2.0 coronary arteries per patient and was successful in 85%. We observed a decline in angina pectoris classification (CCS) from 3.5 to 1.6. An average reduction of 1.1 NYHA class was achieved. The in-hospital mortality was 8.6% (3 patients: 1 x sepsis, 1 x early reocclusion, 1 x cerebral embolism). At 24 months follow-up, a re-PTCA was necessary in four cases because of restenosis. In the remainder, NYHA and CCS class were stable during the follow-up period. An additional five patients died during the first year and two patients in the second year. We conclude that PTCA with the use of a cardiac assist device shows favorable short-term results in a subset of patients with extended coronary artery disease and severely impaired LV function who are not suitable for nonsupported PTCA or CABG due to their risk profile. However, the long term results are not satisfying and stress the need for complete revascularisation with CABG once the patient's condition is stabilized by means of supported PTCA.     

Global Implications of the Information Society

"As with life itself, the prognosis for an information society is mixed, the remedy inconclusive."     

Polymeric nanofibers via flat spinneret electrospinning

Electrospun nanofibers are most often produced by needle electrospinning process, which has inherent disadvantages like clogging and low efficiency. In this study, an alternative needleless electrospinning process is reported for the fabrication of nanofibers based on a novel spinneret. Firstly, a spinneret with a 0.5‐mm diameter hole in the middle of a flat plastic cap was custom‐made that may be readily scaled up for mass production. Then, polyethylene oxide (PEO) aqueous solution with 6.0 wt% concentration was used to demonstrate the needleless electrospinning process. The processing window for the jet formation in the flat spinneret electrospinning process was determined. The relationships between various processing parameters (applied voltage, working distance, and flow rate) and the resultant PEO nanofibers were also investigated. It was found that stable fluid jet launched from the tip of the coned droplet anchored at the rim of the hole and formed fibers. The morphology and diameter of electrospun fibers were examined using scanning electron microscopy. The results show that PEO nanofibers produced by this needleless electrospinning have similar structure and morphology to those from the single needle source. Finally, the hole number of spinneret was increased to four holes, which was still able to produce smooth nanofibers with a higher production rate. POLYM. ENG. SCI., 2009. © 2009 Society of Plastics Engineers