Comment on ``Consistent Sets Yield Contrary Inferences in Quantum Theory''

In a recent paper Kent has pointed out that in consistent histories quantum theory it is possible, given initial and final states, to construct two different consistent families of histories, in each of which there is a proposition that can be inferred with probability one, and such that the projectors representing these two propositions are mutually orthogonal. In this note we stress that, according to the rules of consistent history reasoning two such propositions are not contrary in the usual logical sense namely, that one can infer that if one is true then the other is false, and both could be false. No single consistent family contains both propositions, together with the initial and final states, and hence the propositions cannot be logically compared. Consistent histories quantum theory is logically consistent, consistent with experiment as far as is known, consistent with the usual quantum predictions for measurements, and applicable to the most general physical systems. It may not be the only theory with these properties, but in our opinion, it is the most promising among present possibilities.Comment: 2pages, uses REVTEX 3.

Identifying the health care-initiated and self-initiated interventions used by women for the management of rectal emptying difficulty secondary to obstructive defecation: a scoping review protocol.

OBJECTIVE: This scoping review aims to identify interventions used by women for the management of rectal emptying difficulty secondary to obstructive defecation. INTRODUCTION: Rectal emptying difficulty is typically a symptom of obstructive defecation syndrome. Even though a range of interventions are already available for this condition, this review is necessary to increase understanding of what interventions women find useful and are acceptable for them. This depth of understanding will facilitate the development of a specific care pathway to support women living with rectal emptying difficulty secondary to obstructive defecation syndrome. INCLUSION CRITERIA: This review will consider studies that include adult women (over 18 years of age) living in the community who have experienced difficulty with rectal emptying secondary to obstructive defecation and who have not had surgical intervention. Exclusion criteria include prolapse surgery and surgical techniques, oral laxatives, vaginal pessaries, cognitive impairment, pregnancy, and those residing in care homes. METHODS: The databases to be searched include MEDLINE, Embase, CINAHL, PsycINFO, Emcare, AMED, Web of Science, Scopus, PROSPERO, Open Grey, ClinicalTrials.gov, International Clinical Trials Registry Platform Search Portal, UK Clinical Trials Gateway, International Standard Randomised Controlled Trial Number Registry, JBI Evidence Synthesis, Epistemonikos, Cochrane Library, and gray literature. Studies conducted in English from any time period will be considered for inclusion. The titles and abstracts will then be screened by two independent reviewers for assessment against the inclusion criteria for the review

Reducing Crop Production Cost

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Theory and Application of Dissociative Electron Capture in Molecular Identification

The coupling of an electron monochromator (EM) to a mass spectrometer (MS) has created a new analytical technique, EM-MS, for the investigation of electrophilic compounds. This method provides a powerful tool for molecular identification of compounds contained in complex matrices, such as environmental samples. EM-MS expands the application and selectivity of traditional MS through the inclusion of a new dimension in the space of molecular characteristics--the electron resonance energy spectrum. However, before this tool can realize its full potential, it will be necessary to create a library of resonance energy scans from standards of the molecules for which EM-MS offers a practical means of detection. Here, an approach supplementing direct measurement with chemical inference and quantum scattering theory is presented to demonstrate the feasibility of directly calculating resonance energy spectra. This approach makes use of the symmetry of the transition-matrix element of the captured electron to discriminate between the spectra of isomers. As a way of validating this approach, the resonance values for twenty-five nitrated aromatic compounds were measured along with their relative abundance. Subsequently, the spectra for the isomers of nitrotoluene were shown to be consistent with the symmetry-based model. The initial success of this treatment suggests that it might be possible to predict negative ion resonances and thus create a library of EM-MS standards.Comment: 18 pages, 7 figure

Determinants of Pulmonary Hypertension in Left Ventricular Dysfunction

AbstractObjectives. This study sought to analyze the determinants of pulmonary hypertension in patients with left ventricular dysfunction.Background. Pulmonary hypertension in patients with left ventricular dysfunction is a predictor of poor outcome. The independent role of cardiac functional abnormalities in the genesis of pulmonary hypertension is unclear.Methods. In 102 consecutive patients with primary left ventricular dysfunction (ejection fraction <50%), systolic pulmonary artery pressure was prospectively measured by Doppler echocardiography (using tricuspid regurgitant velocity), and left ventricular systolic and diastolic function, functional mitral regurgitation, cardiac output and left atrial volume were quantified.Results. Systolic pulmonary artery pressure was elevated in patients with left ventricular dysfunction (51 ± 14 mm Hg [mean ± SD]), but the range was wide (23 to 87 mm Hg). Of the numerous variables correlating significantly with systolic pulmonary artery pressure, the strongest were mitral deceleration time (r = −0.61, p = 0.0001; odds ratio of pulmonary pressure ≥50 mm Hg [95% confidence interval] if <150 ms, 48.8 [14.8 to 161]) and mitral effective regurgitant orifice (r = 0.50, p = 0.0001; odds ratio [95% confidence interval] if ≥20 mm2, 5.9 [2.3 to 15.5]). In multivariate analysis, these two variables were the strongest predictors of systolic pulmonary artery pressure in association with age (p = 0.005). Ejection fraction or end-systolic volume was not an independent predictor of pulmonary artery pressure.Conclusions. Pulmonary hypertension is frequent and highly variable in patients with left ventricular dysfunction. It is not independently related to the degree of left ventricular systolic dysfunction but is strongly associated with diastolic dysfunction (shorter mitral deceleration time) and the degree of functional mitral regurgitation (larger effective regurgitant orifice). These results emphasize the importance of assessing diastolic function and quantifying mitral regurgitation in patients with left ventricular dysfunction.(J Am Coll Cardiol 1997;29:153–9)

Amplitude-weighted mean velocity: Clinical utilization for quantitation of mitral regurgitation

AbstractObjectives. The purpose of this study was to determine the clinical usefulness of the amplitude-weighted mean velocity method for quantitation of mitral regurgitation.Background. Amplitude-weighted mean velocity is a nonvolumetric method for calculating the mitral regurgitant fraction. Its previous validation at one center mandated an independent assessment of its usefulness and limitations.Methods. In 56 patients with and 16 patients without mitral regugitation, the regurgitant fraction was measured simultaneously by amplitude-weighted mean velocity, quantitative Doppler study and quantitative two-dimensional echocardiography. In 16 patients, multiple gain settings were used to determine the influence of this variable on amplitude-weighted mean velocity.Results. In ptients without regurgitation, amplitude-weighted mean velocity showed more scattering of regurgitant fraction (−18% to 23%) than Doppler (p = 0.016) or two-dimensional echocardiography (p = 0.022). The absolute value of regurgitant fraction was (mean ± SD) 8 ± 6%, 4 ± 2% and 4 ± 3%, respectively (p = NS). With increasing gain, the amplitudeweighted mean velocity mitral and aortic integrals increased, but the calculated regurgitant fraction remained unchanged. In patients with mitral regurgitation, significant correlation was found between amplitude-weighted mean velocity and Doppler study (r = 0.79, p = 0.0001) and between implitude-weighted mean velocity and two-dimensional echocardiography (r = 0.76, p = 0.0001) for calculated regurgitant fraction, but the standard error of the estimate (12%) was large.Conclusions. The amplitude-weighted mean velocitycalculated regurgitant fraction is gain independent, whereas the aortic and mitral integrals are gain dependent. Compared with Doppler and two-dimensional echocardiography, It shows more scattering of values in patients without regurgitation, but the methods correlate significantly in patients with mitral regurgitation. Amplitude-weighted mean velocity can be used as a simple adjunctive tool for comprehensive, noninvasive quantitation of mitral regurgitation

Measurement of glucose exclusion from the fully hydrated DOPE inverse hexagonal phase

The degree of exclusion of glucose from the inverse hexagonal HII phase of fully hydrated DOPE is determined using contrast variation small angle neutron scattering and small angle X-ray scattering. The presence of glucose is found to favour the formation of the non-lamellar HII phase over the fluid lamellar phase, over a wide range of temperatures, while having no significant effect on the structure of the HII phase. Glucose is preferentially excluded from the lipid-water interface resulting in a glucose concentration in the HII phase of less than half that in the coexisting aqueous phase. The degree of exclusion is quantified and the results are consistent with a hydration layer of pure water adjacent to the lipid head groups from which glucose is excluded. The osmotic gradient created by the difference in glucose concentration is determined and the influence of glucose on the phase behaviour of non-lamellar phase forming lipid systems is discussed