On the capacities of bipartite Hamiltonians and unitary gates

We consider interactions as bidirectional channels. We investigate the capacities for interaction Hamiltonians and nonlocal unitary gates to generate entanglement and transmit classical information. We give analytic expressions for the entanglement generating capacity and entanglement-assisted one-way classical communication capacity of interactions, and show that these quantities are additive, so that the asymptotic capacities equal the corresponding 1-shot capacities. We give general bounds on other capacities, discuss some examples, and conclude with some open questions.     

A tight lower bound on the classical communication cost of entanglement dilution

Suppose two distant observers, Alice and Bob, share some form of entanglement - quantum correlations - in some bipartite pure quantum states. They may apply local operations and classical communication to convert one form of entanglement to another. Since entanglement is regarded as a resource in quantum information processing, it is an important question to ask how much classical communication, which is also a resource, is needed in the inter-conversion process of entanglement. In this paper, we address this important question in the many-copy case. The inter-conversion process of entanglement is usually divided into two types: concentrating the entanglement from many partially entangled states into a smaller number of maximally entangled states (i.e., singlets) and the reverse process of diluting singlets into partially entangled states. It is known that entanglement concentration requires no classical communication, but the best prior art result for diluting to N copies of a partially entangled state requires an amount of communication on the order of /spl radic/N. Our main result is to prove that this prior art result is optimal up to a constant factor; any procedure for approximately creating N partially entangled states from singlets requires /spl Omega/(/spl radic/N) bits of classical communication. Previously not even a constant bound was known for approximate entanglement transformations. We also prove a lower bound on the inefficiency of the process: to dilute singlets to N copies of a partially entangled state, the entropy of entanglement must decrease by /spl Omega/(/spl radic/N). Moreover, we introduce two new tools - /spl delta/-significant subspaces and the standard form protocol reduction in entanglement manipulations. We hope that these two new tools will be useful in other work in quantum information theory.     

Patient, physician and presentational influences on clinical decision making for breast cancer: results from a factorial experiment

This study examines the influence of six patient characteristics (age, race, socioeconomic status, comorbidities, mobility and presentational style) and two physician characteristics (medical specialty and years of clinical experience) on physicians' clinical decision making behaviour in the evaluation treatment of an unknown and known breast cancer. Physicians' variability and certainty associated with diagnostic and treatment behaviour were also examined. Separate analyses explored the influence of these non-medical factors on physicians' cognitive processes. Using a fractional factorial design, 128 practising physicians were shown two videotaped scenarios and asked about possible diagnoses and medical recommendations. Results showed that physicians displayed considerable variability in response to several patient-based factors. Physician characteristics also emerged as important predictors of clinical behaviour, thus confirming the complexity of the medical decision-making process.     

Overinclusive thinking in acute schizophrenic patients.

Investigated 2 types of overinclusive thinking, behavioral and conceptual, in 110 acute psychiatric inpatients. The Object Sorting Test was administered and scored for the 2 types of overinclusion and for idiosyncratic (bizarre) thinking and rich associations. Results on behavioral overinclusion and rich associations were mixed. Behavioral overinclusion was more frequent in schizophrenics, but was also found in many acute nonschizophrenics. Conceptual overinclusion and idiosyncratic thinking were significantly more frequent among acute schizophrenics and were also found in delusional patients regardless of diagnosis. (41 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Associative disturbance in schizophrenia, schizoaffective disorders, and major affective disorders: Comparisons between hospitalization and 1-year follow-up.

Word-association performance of 71 Research Diagnostic Criteria-diagnosed schizophrenic, schizoaffective, and affective disorder patients was assessed shortly after hospital admission to evaluate the diagnostic specificity of associative disturbance. The same Ss were assessed again 1 yr after discharge to investigate the longitudinal course of word-association behavior. Data regarding rehospitalization were included in the analyses of 4 primary word-association indices. Results indicate that thought disorder was not distinctively schizophrenic and that associative thought disorder was more characteristically associated with rehospitalization for affective disorder patients than for other diagnostic groups. Arousal and cognitive control mechanisms are discussed. (3 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Self-concept of the married psychiatric patient and his mate's perception of him.

26 married psychiatric patients and their spouses were administered a 50-item questionnnaire to assess their concepts of themselves and of each other 1 wk. after acute hospitalization and then again 7 wk. later. Ss' initial self-images and their mates' perception of them were both more negative than their own and their spouses' images of the average person. Ss and their mates viewed the S as the most disturbed family member with both seeing the spouse in a more positive light than the S. Ss' self-images improved during hospitalization. The spouses' images of the Ss also tended to become more positive, but the spouses still viewed the Ss more negatively than themselves. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The course of anhedonia during 10 years of schizophrenic illness.

Although anhedonia has been proposed to be a trait-like characteristic in schizophrenia patients, its persistence and stability have not been tested using multiple assessments over a multiyear period. Specific definitions of anhedonia vary across studies, and relationships between different types of anhedonia as well as their relationship to schizophrenic symptoms over the course of illness have not been addressed. The current research, using prospectively collected longitudinal data covering a 10-year span for 127 individuals with schizophrenic illness, found that (a) physical, but not depressive, anhedonia is a stable characteristic over a 10-year period; (b) physical anhedonia does not show strong and consistent relationships with psychotic, negative, or depressive symptoms; and (c) the relationship between some premorbid characteristics and physical anhedonia are significant even 10 years into the course of illness. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An ultrafiltration monitor for hemodialysis research

The ultrafitration rate of hemodialysis membranes should be carefully controlled for maximum patient benefit. A special purpose instrument is described that takes in analog pressure information and the analog output of an appropriate weighing system and produces both digital displays and analog outputs (for a strip-chart recorder) of ultrafiltration rate and ultrafiltration index as well as the averaged mean transmembrane hydrostatic pressure drop and volume of ultrafiltrate. The instrument normally uses an averaging time of about 2 min.     

Epidemiology and clinical consequences of drug-resistant tuberculosis in a Guatemalan hospital

STUDY OBJECTIVE: To determine the epidemiology and clinical consequences of drug-resistant TB in Guatemala. DESIGN: A prospective study conducted for 12 months. SETTING: A thoracic referral hospital in western Guatemala. PATIENTS: Three hundred and seventy-six patients with confirmed TB. RESULTS: Of 376 confirmed cases, 335 (89%) were culture-positive. Tests of drug sensitivities to four first-line antituberculous drugs were performed in 172 (51%) of the culture-positive cases. Fifty-one patients (30%) were resistant to at least one antimicrobial agent, and 26 (15%) were resistant to at least two drugs. In a multivariate model of clinically available patient characteristics, only cavitary disease (odds ratio=2.1; 95% confidence interval, 1.1-6.6) and a history of taking anti-TB medication for >2 weeks (OR=3.0; 95% CI, 1.5-10.3) were independent predictors of resistance to two or more anti-TB agents. Resistance to two or more anti-TB drugs was the single independent predictor of treatment failure (OR=6.4; 95% CI, 2.3-17.8). Twenty-four of 172 patients (14%) who denied having received prior anti-TB therapy were infected with resistant organisms, suggesting ongoing transmission of drug-resistant strains. Although 84% (69 of 82 cases) of patients with fully susceptible organisms and 89% (17 of 19 cases) with singly resistant organisms were cured, only 45% of patients (10 of 22 cases) infected with organisms resistant to two or more agents were successfully treated. CONCLUSIONS: At this sentinel site for complicated TB, a substantial subset of cases who are infected with drug-resistant bacteria cannot be easily identified or treated.