Search results for "Curve"

Adaptation to fluctuations in temperature by nine species of bacteria

2018

Rapid environmental fluctuations are ubiquitous in the wild, yet majority of experimental studies mostly consider effects of slow fluctuations on organism. To test the evolutionary consequences of fast fluctuations, we conducted nine independent experimental evolution experiments with bacteria. Experimental conditions were same for all species, and we allowed them to evolve either in fluctuating temperature alternating rapidly between 20°C and 40°C or at constant 30°C temperature. After experimental evolution, we tested the performance of the clones in both rapid fluctuation and in constant environments (20°C, 30°C and 40°C). Results from experiments on these nine species were combined meta…

2015

Background and purpose Silent atrial fibrillation (AF) and tachycardia (AT) are considered precursors of ischaemic stroke. Therefore, detection of paroxysmal atrial rhythm disorders is highly relevant, but is clinically challenging. We aimed to evaluate the diagnostic value of natriuretic peptide levels in the detection of paroxysmal AT/AF in a pilot study. Methods Natriuretic peptide levels were analysed in two independent patient cohorts (162 patients with arterial hypertension or other cardiovascular risk factors and 82 patients with retinal vessel disease). N-terminal-pro-brain natriuretic peptide (NT-proBNP) and BNP were measured before the start of a 7-day Holter monitoring period car…

Definition of tachycardia for risk stratification of pulmonary embolism

2020

Tachycardia is a reliable predictor of adverse outcomes in normotensive patients with acute pulmonary embolism (PE). However, different prognostic relevant heart rate thresholds have been proposed. The aim of the study was to investigate the prognostic performance of different thresholds used for defining tachycardia in normotensive PE patients.We performed a post-hoc analysis of normotensive patients with confirmed PE consecutively included in a single-centre and a multi-centre registry. An adverse outcome was defined as PE-related death, need for mechanical ventilation, cardiopulmonary resuscitation or administration of catecholamines.Of 1567 patients (median age: 72 [IQR, 59-79] years; f…

Electrochemical dating of archaeological gold based on refined peak current determinations and Tafel analysis

2020

Abstract This report proposes a refined method to date archaeological gold samples based on the Tafel analysis of the ascending part of voltammetric curves corresponding to the oxidation of surface flakes of gold in contact with hydrochloric acid aqueous electrolyte. This allows estimating the equilibrium potential of gold oxidation correcting for irreversibility effects. This equilibrium potential can be correlated with the coverage of adsorbed oxygen species and hence the estimated age of the gold samples. A satisfactory potential/time calibration graph was constructed from a set of archaeological samples including two sets of samples from the Mapungubwe Gold Collection, South Africa (120…

Two-dimensional parametric parenchymal blood flow in transarterial chemoembolisation for hepatocellular carcinoma: perfusion change quantification an…

2020

Aim To evaluate the feasibility and potential value of two-dimensional (2D) parametric parenchymal blood flow (2D-PPBF) for the assessment of perfusion changes during transarterial chemoembolisation with drug-eluting beads (DEB-TACE) and to analyse correlations of 2D-PPBF parameters and tumour response. Materials and methods Thirty-two patients (six women, 26 men, mean age: 67±8.9 years) with unresectable hepatocellular carcinoma (HCC) who underwent their first DEB-TACE were included in this study. To quantify perfusion changes using 2D-PPBF, the acquired digital subtraction angiography (DSA) series were post-processed. Ratios were calculated between the reference region of interest (ROI) a…

Developing and Comparing Indices to Evaluate Community Knowledge Building in an Educational Research Course

2022

This paper implements a novel approach to analyzing the degree of Collective Cognitive Responsibility (CCR) in a Knowledge Building community, based on socioeconomic and scientometric measures. After engaging in Knowledge Forum (KF) discussions for one semester, 36 students identified impactful ideas in their portfolios, which were then used to develop their impact scores. These scores were then transformed and plotted along the Lorenz Curve and the Gini coefficient to visualize the degree of equidistribution of recognition in the community and, by extension, the degree of collective responsibility shared by members of the community. Additionally, students were classified into member roles …

Screening of some banned aromatic amines in textile products from Indian bandhani and gamthi fabric and in human sweat using micellar liquid chromato…

2021

Certain dyes in textile products, which are capable of reductively splitting into carcinogenic aromatic amines, are strictly controlled in many countries. A simple, rapid, sensitive and green chromatographic method has been developed and validated for the simultaneous determination of 4-aminophenol (4-AMP), p-phenylenediamine (p-PPD) and benzidine (BNZ), banned aromatic amines in dyeing clothes and human sweat. The separation was achieved using a micellar mobile phase of 0.1 M SDS, 4% 1- butanol (v/v) buffered to pH 7 with sodium dihydrogen phosphate, flowing under isocratic mode at 1 mL/min through a C18 column. Photodiode array detector was set at 210 nm. Using the above chromatographic c…

Retail pricing decisions and product category competitive structure

2010

This study addresses the use of demand forecasting techniques by retailers to support their decision making. Specifically, the authors propose a pricing decision support model for retailers to estimate optimal prices, whose output depends on the configuration of a supporting measurement model. The measurement model is a demand function that relates sales and prices within the category; optimal prices are those whose effects on demand and retail margins maximize the category's profitability. This investigation focuses particularly on the role of competitive structure, such that the authors consider two types of price competition asymmetries for demand forecasting: those depending on the bran…

Nanocomposites based on esterified colophony and halloysite clay nanotubes as consolidants for waterlogged archaeological woods

2017

We have designed an innovative protocol for the consolidation of waterlogged archaeological woods by using acetone mixtures of halloysite clay nanotubes and a chemically modified colophony (Rosin). Firstly, we have investigated the thermal properties of HNTs/Rosin nanocomposites, which have been prepared by means of the casting method from acetone. The HNTs content have been systematically changed in order to study the influence of the inorganic filler on the thermal stability and glass transition process of Rosin. We have observed that the thermal properties of the hybrids are affected by the specific HNTs/Rosin interactions. Then, acetone dispersions of HNTs/Rosin composites at variable f…

Thermal and hygrometric properties of traditional calcarenite stones in the area of Palermo

2017

Il contributo espone le misure di conducibilità termica svolte su tre conci di calcarenite conchiliare e la caratterizzazione igrometrica di uno di essi. I risultati sono confrontati con i dati termici e igrometrici riportati dalle norme tecniche esistenti (UNI 10351, UNI EN ISO 10456, UNI EN 1745). The energy improvement of historic buildings requires detailed knowledge of the thermal and hygrometric properties of traditional materials and components. These data should be collected for specific local contexts, where the features of historic constructions are comparable. For the purpose of developing this tool for the architectural heritage of Palermo, this research focuses on calcarenite s…