4,616 research outputs found
Quantum Stochastic Processes and the Modelling of Quantum Noise
This brief article gives an overview of quantum mechanics as a {\em quantum
probability theory}. It begins with a review of the basic operator-algebraic
elements that connect probability theory with quantum probability theory. Then
quantum stochastic processes is formulated as a generalization of stochastic
processes within the framework of quantum probability theory. Quantum Markov
models from quantum optics are used to explicitly illustrate the underlying
abstract concepts and their connections to the quantum regression theorem from
quantum optics.Comment: 14 pages, invited article for the second edition of Springer's
Encyclopedia of Systems and Control (to appear). Comments welcom
Clinical impact of double protease inhibitor boosting with Lopinavir/Ritonavir and Amprenavir as part of salvage antiretroviral therapy
Purpose: Double protease inhibitor (PI) boosting is being explored as a new strategy in salvage antiretroviral (ARV) therapy. However, if a negative drug interaction leads to decreased drug levels of either or both PIs, double PI boosting could lead to decreased virologic response. A negative drug interaction has been described between amprenavir (APV) and lopinavir/ritonavir (LPV/r). This observational cohort study assessed the virologic impact of the addition of APV to a salvage ARV regimen, which also contains LPV/r, compared to a regimen containing LPV/r alone. Method: Patients initiated on a salvage ARV regimen that included LPV/r obtained from the expanded access program in Toronto, Canada, were evaluated. APV (600-1,200 mg bid) was added at the discretion of the treating physician. Results: Using multivariate Cox proportional hazards models, we found that the addition of APV to a LPV/r-containing salvage regimen was not significantly associated with time to virologic suppression (< 50 copies/mL; adjusted hazard ratio [HR] = 0.75, p = .12) or with time to virologic rebound (adjusted HR = 1.46, p = .34). Those patients who received higher doses of APV had an increased chance of virologic suppression (p = .03). In a subset of 27 patients, the median LPV Ctrough was significantly lower in patients receiving APV (p = .04), and the median APV Ctrough was reduced compared to reported controls. Conclusion: Our data do not support an additional benefit in virologic reduction of double boosting with APV and LPV/r relative to LPV/r alone in salvage ARV therapy. Our study's limitations include its retrospective nature and the imbalance between the two groups potentially confounding the results. Although these factors were adjusted for in the multivariate analysis, a prospective randomized controlled trial is warranted to confirm our findings
Patient perspectives on discussing alcohol as part of medicines review in community pharmacies.
BACKGROUND: This paper reports on a qualitative study which formed part of the intervention development phase of a five year research programme (Community pharmacy: Highlighting Alcohol use in Medication aPpointments; CHAMP-1). OBJECTIVES: To better understand patient views on the appropriateness of alcohol as a subject for discussion in medication reviews in community pharmacy. METHODS: Semi-structured interviews were conducted with a sample of 25 people eligible for medication reviews whose AUDIT-C screening scores identified them as likely risky drinkers. Transcripts were analysed using a modified framework method with a constructionist thematic analysis approach. RESULTS: Most patients interviewed said they were open to the idea of a medication and alcohol linked discussion with a pharmacist if this was routine, well-conducted and confidential. Such a discussion was thought less personally relevant for those who viewed the proposed intervention through the prism of a particular set of ideas about the nature of alcohol problems, which distanced them from thinking about alcohol in terms of their everyday life and possible impacts on their health. Study findings attest to some of the sensitivities involved in discussion of alcohol, and the complexities inherent in helping people to talk about their own drinking, medicine use and health. CONCLUSIONS: Patients were open to the idea of discussing alcohol with community pharmacists in the context of a medicines review if this was sensitively done and the relevance was clear to them
Contemplations on Dirac's equation in quaternionic coordinates
A formulation of Dirac's equation using complex-quaternionic coordinates
appears to yield an enormous gain in formal elegance, as there is no longer any
need to invoke Dirac matrices. This formulation, however, entails several
peculiarities, which we investigate and attempt to interpret
Using qualitative process evaluation in the development of a complex intervention to advance person-centred practice by pharmacists: The Medicines and Alcohol Consultation (MAC)
In order to effectively evaluate complex interventions, there have been calls for the further integration of qualitative methods. Qualitative process studies of brief alcohol interventions and medicines reviews are notably lacking. This article provides a grounded example through the presentation of findings from an embedded qualitative process evaluation of a multi-site, pilot cluster RCT of a new intervention: the Medicines and Alcohol Consultation (MAC). MAC is designed to increase the capacity of community pharmacists (CPs) to conduct person-centred medicines reviews in which the subject of alcohol consumption is raised in connection with medications and associated health conditions. Participant-focused qualitative studies (interviews, observations, recorded consultations) sought to understand how CPs engaged with and implemented MAC in context. This article documents effects of the intervention on developing person-centred consultation practice and highlights how qualitative process studies can be used formatively to develop middle range programme theory and to optimise intervention design for testing in a definitive RCT
Gravitational Helioseismology?
The magnitudes of the external gravitational perturbations associated with
the normal modes of the Sun are evaluated to determine whether these solar
oscillations could be observed with the proposed Laser Interferometer Space
Antenna (LISA), a network of satellites designed to detect gravitational
radiation. The modes of relevance to LISA---the , low-order , and
-modes---have not been conclusively observed to date. We find that the
energy in these modes must be greater than about in order
to be observable above the LISA detector noise. These mode energies are larger
than generally expected, but are much smaller than the current observational
upper limits. LISA may be confusion-limited at the relevant frequencies due to
the galactic background from short-period white dwarf binaries. Present
estimates of the number of these binaries would require the solar modes to have
energies above about to be observable by LISA.Comment: 8 pages; prepared with REVTEX 3.0 LaTeX macro
Tropical ancient DNA from bulk archaeological fish bone reveals the subsistence practices of a historic coastal community in southwest Madagascar
Taxonomic identification of archaeological fish bones provides important insights into the subsistence practices of ancient coastal peoples. However, it can be difficult to execute robust morphological identification of fish bones from species-rich fossil assemblages, especially from post-cranial material with few distinguishing features. Fragmentation, weathering and burning further impede taxonomic identification, resulting in large numbers of unidentifiable bones from archaeological sites. This limitation can be somewhat mitigated by taking an ancient DNA (aDNA) bulk-bone metabarcoding (BBM) approach to faunal identification, where DNA from non-diagnostic bone fragments is extracted and sequenced in parallel. However, a large proportion of fishing communities (both past and present) live in tropical regions that have sub-optimal conditions for long-term aDNA preservation. To date, the BBM method has never been applied to fish bones before, or to fossils excavated from an exposed context within a tropical climate. Here, we demonstrate that morphologically indistinct bulk fish bone from the tropics can be identified by sequencing aDNA extracted from 100 to 300 ya archaeological midden material in southwest Madagascar. Despite the biases of the approach, we rapidly obtained family, genus, and species-level assemblage information, and used this to describe a subset of the ichthyofauna exploited by an 18th century fishing community. We identified 23 families of fish, including benthic, pelagic, and coral-dwelling fishes, suggesting a reliance on a variety of marine and brackish habitats. When possible, BBM should be used alongside osteological approaches to address the limitations of both; however, this study highlights how genetic methods can nevertheless be a valuable tool for helping resolve faunal assemblages when morphological identification is hindered by taphonomic processes, lack of adequate comparative collections, and time constraints, and can provide a temporal perspective on fish biodiversity in the context of accelerated exploitation of the marine environment
A prospective cohort study of the effects of adjuvant breast cancer chemotherapy on taste function, food liking, appetite and associated nutritional outcomes
\u27Taste\u27 changes are commonly reported during chemotherapy. It is unclear to what extent this relates to actual changes in taste function or to changes in appetite and food liking and how these changes affect dietary intake and nutritional status
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