Ontological indistinguishability as a central tenet of quantum theory.

Quantum indistinguishability directly relates to the philosophical debate on the notions of identity and individuality. They are crucial for our understanding of multipartite quantum systems. Furthermore, the correct interpretation of this feature of quantum theory has implications that transcend fundamental science and philosophy, given that quantum indistinguishability is a resource in quantum information theory. Most of the conceptual analysis of quantum indistinguishability is restricted to studying the permutational invariance of quantum states, the concomitant quantum statistics and their entanglement. Here, we analyse the role of indistinguishability and non-individuality in other areas of quantum theory. We start by analysing how a very peculiar use of indistinguishability underlies Feynman's rules for summing amplitudes in interference phenomena. Next, we study how quantum indistinguishability is underestimated in several topics of debate in the quantum physics literature, such as the Einstein-Podolsky-Rosen argument, Bell's inequalities and the Bell-Kochen-Specker theorem. Finally, we argue that an ontology of truly indistinguishable entities can serve as a basis for a quantum ontology that can give interesting answers to the interpretational problems of quantum mechanics. We claim that, in addition to superposition, contextuality and entanglement, indistinguishability (understood in a robust ontological sense) is one of the central features of quantum physics. This article is part of the theme issue 'Identity, individuality and indistinguishability in physics and mathematics'.

Severity of precapillary pulmonary hypertension: Predictive factor.

BACKGROUND AND OBJECTIVES: Patients with pulmonary arterial hypertension (PAH) require risk assessments for prognosis and appropriate therapy. These assessments need to be improved by incorporating clinical and laboratory data such as the analysis of the right ventricle. We aim to establish echocardiographic morphometric data of the right ventricle and its relationship with the left ventricle, to estimate the hemodynamic severity of precapillary pulmonary hypertension (PHprecapillary). METHODS: This cohort, prospective, observational, and cross-sectional study included 41 consecutive patients with PHprecapillary using echocardiographic study and cardiac catheterization. RESULTS: Patients' mean age was 44.0±16.4 years, and 37 were women (90.2%). Idiopathic PAH was diagnosed in 18 patients (43.9%). The World Health Organization/New York Association functional class was III or IV in 31 patients (75.6%). The ratio of the right to left ventricles (RV/LV) echocardiographic diastolic diameters was associated with pulmonary arterial pressures in cardiac catheterization, with the best cutoff per receiver operating characteristic curve being 0.8 for systolic pressure (sensitivity 90.0%, specificity 78.3%, area under the curve [AUC] 0.882) and mean pressure (sensitivity 60.0%, specificity 95.7%, AUC 0.823). Spearman's correlation (R) of RV/LV echocardiographic ratio and the hemodynamic variables was significant for systolic pressure (R = 0.7015, p < 0.0001), mean pressure (R = 0.6332, p < 0.0001), transpulmonary pressure gradient (R = 0.6524, p < 0.0001), pulmonary vascular resistance (R = 0.6076, p = 0.0021), and pulmonary vascular resistance index (R = 0.6229, p = 0.0014). CONCLUSION: The ratio of RV/LV echocardiographic diastolic diameters contribute to the estimates the hemodynamic severity of precapillary pulmonary hypertension. The best cutoff for this assessment was RV/LV of 0.8.

Construct validity and reliability of the Brazilian version of the Falls Efficacy Scale in patients with COPD.

INTRODUCTION AND OBJECTIVE: The Brazilian version of Falls Efficacy Scale (FES-BR) used to assess the fear of falling, has not yet been validated in patients with Chronic Obstructive Pulmonary Disease (COPD). The aim of the present study was to investigate the construct validity and reliability of the (FES-BR) in patients with COPD. METHODS: A cross-sectional study involving subjects with COPD, aged between 48 and 83 years. Data were collected by two independent and blind assessors. Construct validity was assessed using the Spearman's rank correlation coefficient between FES-BR and Berg Balance Scale, Downton fall risk index, Timed Up and Go Test (TUG), hand-grip strength (HGS), Five Times Sit to Stand Test (FTSST) and 6-Minute Walk Test (6MWT). Reliability was measured by the Cronbach's alpha coefficient, Intraclass Correlation Coefficient (ICC), and Bland-Altman plot. RESULTS: The study included 60 subjects aged 68.3 ±â€¯9.9 years and FEV1 56.0 ±â€¯19.3. The correlations were significantly strong between FES-BR and the Berg Balance Scale (r = -0.66), TUG (r = 0.64), HGS (r = 0.61) and FTSST (r = 0.62); and moderate between FES-BR and the Downton fall risk index (r = 0.38) and the 6MWT (r = -0.48). All correlations had p < 0.001. Intra-rater [ICC = 0.94, (95% CI = 0.91-0.96)] and inter-rater [0.97, (95% CI = 0.97-0.98)] reliability were considered excellent. CONCLUSIONS: The Brazilian version of FES was valid and reliable in assess fear of falling in subjects with COPD.

[Applicability of the Torrington and Henderson scale]. / Aplicabilidade da escala de Torrington e Henderson.

PURPOSE: To validate the Torrington & Henderson preoperative risk assessment program in the population of surgical patients in an university hospital (Hospital São Paulo, UNIFESP, São Paulo, Brasil). MATERIAL AND METHODS: We evaluated 1162 patients who underwent to major thoracic, upper and under abdominal surgery using the Torrington & Henderson program. The patients were classified in low (785), moderate (317) and high risk (60). All patients were accompanied daily during the postoperative period by the same medical team which assessed the preoperative period, until discharged or died. RESULTS: The postoperative pulmonary complications were present in 6.1%, 23.3% and 35.0% in the low, moderate and high risk respectively. The relative risk to develop postoperative pulmonary complications was 3.8 higher in the patients with moderate risk and 5.7 higher in the patients with high risk. The mortality rate due to pulmonary complications was 1.7%, 6.3% and 11.7% respectively in the patients with low, moderate and high risk. The relative risk to the death was 3.7 higher in the patients with moderate risk and 6.9 in the high risk. CONCLUSION: We concluded that the Torrington & Henderson preoperative risk assessment program can identify in our population patients who will develop postoperative pulmonary complications.

One more case of the double standard: discrepancies between drug information provided to Brazilian and American physicians.

Several factors have been identified as exerting influences upon the physician prescribing behaviour. Some studies on this issue emphasize the role played by the sources of information available to physicians. A number of reports have been published on the influence of marketing strategies upon these professionals. Such strategies include advertisements in medical journals, detail-men, free samples, distribution of folders, leaflets and gifts, as well as support to congresses and symposia. The impact of the 'special' relationships that manufacturers cultivate with health authorities and physicians and considered opinion-makers should also not be underestimated. This study aimed to evaluate the quality of information provided by a widely-used Brazilian prescribing guide, the Dicionário de Especialidades Farmacêuticas(DEF) on the 44 best-selling pharmaceutical products in Brazil. WHO criteria for drug information were used as parameters of which information is of such outstanding importance that it should be included in any informative material offered to physicians. The information in the DEF was compared with that available for the same products in the PDR (Physicians' Desk Reference) and USP-DI (Drug Information for the Health Care Professional) used by prescribers in USA. Results show the absence of important data from the Brazilian manual, including contraindications, adverse effects and drug interactions. These findings suggest that poor quality information may potentially contribute to the irrational use of drugs. Copyright (c) 2000 John Wiley & Sons, Ltd.