Bayes' theorem and quantum retrodiction

Abstract

We derive on the basis of Bayes' theorem a simple but general expression for the retrodicted premeasurement state associated with the result of any measurement. The retrodictive density operator is the normalized probability operator measure element associated with the result. We examine applications to quantum optical cryptography and to the optical beam splitter.     

Experimental demonstration of polarization discrimination at the Helstrom bound

Abstract

We present an experimental realization of discrimination between non-orthogonal polarization states at the Helstrom bound for minimum probability of error. The experiment was performed with highly attenuated laser light with a mean number of about 0·1 photons per pulse.     

Preventing problems of professional competence in the face of life-threatening illness.

When a psychologist is diagnosed with a serious medical condition and faces the prospect of an arduous treatment regimen and perhaps a bleak prognosis, it may be difficult to attend to one's level of professional competence. Like their clients, psychologists are vulnerable to distress and diminished functioning caused by a life-threatening illness. Psychologists have an ethical responsibility to monitor and ensure professional competence, yet the distress and distraction that accompany serious health problems can inhibit and undermine self-assessments of competence in many ways; distressed psychologists may react with denial, shame, fear, and problematic countertransference responses. The limitations associated with evaluating competence in the context of distress are discussed and several recommendations are offered for psychologists who deliver services, support gravely ill colleagues, and serve in credentialing and regulatory capacities. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Quantitation of amphetamine,methamphetamine, and their methylenedioxy derivatives in urine by solid-phase microextraction coupled with electrospray ionization-high-field asymmetric waveform ion mobility spectrometry-mass spectrometry

Amphetamine, methamphetamine, and their methylenedioxy derivatives have been identified and measured in a human urine matrix using solid-phase microextraction (SPME) and high-field asymmetric waveform ion mobility spectrometry (FAIMS) in combination with electrospray ionization (ESI) and mass spectrometric detection (MS). Limits of detection in human urine between 200 pg/mL and 7.5 ng/mL have been achieved. The use of a simple extraction method, SPME, combined with the high sensitivity and selectivity of ESI-FAIMS-MS eliminates the need for chromatographic separation and allows for very rapid sample processing.     

Investigation of wear of knee prostheses in a new displacement/force-controlled simulator

The performance of two knee simulators designed by ProSim (Manchester, UK) was evaluated by comparison of the wear seen in the press-fit condylar (PFC) Sigma (DePuy) knee prosthesis. Twelve specimens of the same design and manufacturing specification, were subjected to a wear test of 2 x 10(6) cycles duration using bovine serum as a lubricant. The anterior/posterior displacement and internal/external rotation inputs were based on the kinematics of the natural knee. International Standards Organization (ISO) standards were used for the flexion and axial load. The wear rates and wear scar areas were compared across all stations. The mean wear rates found were 17.6+/-5 mm3/10(6) cycles for stations 1 to 6 and 19.6+/-4 mm3/10(6) cycles for stations 7 to 12, resulting in an overall mean wear rate of 18.1+/-3 mm3/10(6) cycles. The differences between the two simulators were not significant. The average wear scar area seen on inserts from stations I to 6 was calculated at 32.4+/-1 per cent of the intended articulating surface. Similarly on stations 7 to 12 the average wear scar area was 30.7+/-3 per cent. The wear scars seen were a good physiological representation of those found from clinical explant data. This study has shown good repeatability from the simulator, both within and between the simulators.     

Alcohol-related and alcohol-free activity participation and enjoyment among college students: A behavioral theories of choice analysis.

College student alcohol abuse remains a significant public health problem, and there is a need for theory-driven and empirically based models to guide prevention efforts. Behavioral theories of choice assume that the decision to consume alcohol is influenced by the relative value of alcohol versus other available activities. In the present study, a sample of college student drinkers (N=108; 56% female, 44% male) who had previously completed a mandatory alcohol intervention completed a measure of alcohol-related and alcohol-free activity participation and enjoyment. The goals of the study were to examine the influence of drinking quantity and contextual variables on activity enjoyment and to identify enjoyable alcohol-free activities that take place on evenings when students might otherwise be drinking. Overall, students found alcohol-related activities more enjoyable than alcohol-free activities, and drinking quantity was positively related to enjoyment. However, alcohol-free activities such as watching movies, going to the theater or museums, going to bars or parties, hanging out with friends, eating at restaurants, and engaging in creative activity were generally as enjoyable as drinking. Alcohol-free activities that included peers or dates were more enjoyable than solitary activities. Men were less likely to engage in alcohol-free activities that included peers and reported less enjoyment related to alcohol-free activities than did women. Further research is required to identify procedures for increasing participation in alcohol-free activities and to determine whether increased alcohol-free activity participation results in decreased alcohol consumption. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Detection of nine chlorinated and brominated haloacetic acids at part-per-trillion levels using ESI-FAIMS-MS

A combination of electrospray ionization, high-field asymmetric waveform ion mobility spectrometry, and mass spectrometry (ESI-FAIMS-MS) was used for the analysis of a solution containing a mixture of the nine chlorinated and brominated haloacetic acids. For a carrier gas of nitrogen in the FAIMS analyzer, haloacetate anions of the mono- and dihalogenated acids and the decarboxylated anions of three of the trihalogenated acids were detected. No signal was observed for bromodichloroacetic acid (BDCAA) at a dispersion voltage of -3400 V. The addition of a small amount of carbon dioxide to the nitrogen carrier gas resulted in the detection of the pseudomolecular trihaloacetate anions, including BDCA-, and significant increases in sensitivities for the trihalogenated species. The addition of carbon dioxide to the nitrogen carrier gas had little effect on the mono- and dihalogenated anions. Quantitative analysis of the nine haloacetic acids, using flow injection, gave detection limits between 5 and 36 parts-per-trillion in 9/1 methanol/water (v/v) containing 0.2 mM ammonium acetate.     

The guideline interchange format: a model for representing guidelines

Carboxylate and sulfate groups were introduced at the surface of poly(ethylene) (PE) samples. This was accomplished by coating and immobilizing sodium 10-undecenoate (C11(:)) and 10-undecene sulfate (S11(:)) on the polymer by means of an argon plasma treatment. The composition of the coated surfactant layer was proportional to the composition of the coating solution. The thickness of the surfactant layer on the surface of PE samples, which were precoated from an aqueous solution with a total surfactant concentration of 0.30 M, was about 55 A. The presence of carboxylate and sulfate groups after plasma treatment of the precoated surfaces was confirmed by X-ray photoelectron spectroscopy (XPS). About 20% of the initial amount of functional groups of the coated surfactants was retained at the PE surface. The ratio of carboxylate/sulfate groups at the plasma treated surfaces was dependent on the composition of the precoated surfaces. The minimum surface density of these groups on the resulting samples was about one group per 40 A2.