Search results for "QUANTIFICATION"

Rolewicz-type chaotic operators

2015

In this article we introduce a new class of Rolewicz-type operators in l_p, $1 \le p < \infty$. We exhibit a collection F of cardinality continuum of operators of this type which are chaotic and remain so under almost all finite linear combinations, provided that the linear combination has sufficiently large norm. As a corollary to our main result we also obtain that there exists a countable collection of such operators whose all finite linear combinations are chaotic provided that they have sufficiently large norm.

Bifurcations of links of periodic orbits in non-singular Morse–Smale systems with a rotational symmetry on S3

2000

Abstract In this paper we consider a rotational symmetry on a non-singular Morse–Smale (NMS) system analyzing the restrictions this symmetry imposes on the links defined by the set of its periodic orbits and to the appearance of local generic codimension one bifurcations in the set of NMS flows on S 3 . The topological characterization is obtained by writing the involved links in terms of Wada operations. It is also obtained that symmetry implies that in general bifurcations have to be multiple. On the other hand, we also see that there exists a set of links that cannot be related to any other by sequences of this kind of bifurcation.

Sensory evaluation based on verbal judgments

1999

Studies of the repeatability and the homogeneity of expert panel scores in sensory profiling show that lasting and reliable evaluations of food products are difficult to obtain: strong inter- and intra-individual differences are commonly observed. Our hypothesis is that this variability is due to quantification methods that consist of asking panelists to furnish quantitative values (by attributing a numerical point to perceived intensity) and that using natural language in the form of verbal judgements in a hierarchical tree would allow improving the reliability of sensory evaluations. This hypothesis was tested by comparing a numerical value scale and a specific hierarchical semantic scale…

Impact of prompt gamma emission of 44Sc on quantification in preclinical and clinical PET systems

2021

Abstract 44Sc is an increasingly investigated positron emitter for use in positron emission tomography (PET) imaging. However, 44Sc is a non-pure positron emitter, since prompt photons are co-emitted during the decay process. This study investigates coincidence energy spectra of 44Sc and its impact on PET quantification on a preclinical and clinical PET system in comparison with 18F. The raw data of the coincidence events revealed characteristic differences comparing the photon energy distribution of 44Sc and 18F. Due to prompt gamma emission of 44Sc, activity recovery is underestimated on PET systems. However, clinical PET imaging of 44Sc with acceptable quantitative accuracy appears feasi…

Monitoring Stemness in Long-Term hESC Cultures by Real-Time PCR

2009

Human embryonic stem cells (hESC) involve long-term cultures that must remain undifferentiated. The real-time PCR (RT-PCR) technique allows the relative quantification of target genes, including undifferentiation and differentiation markers when referred to a housekeeping control with the addition of a calibrator that serves as an internal control to compare different lots of reactions during the time. The main aspects will include a minimal number of cells to be analyzed, genes to be tested, and how to choose the appropriate calibrator sample and the reference gene. In this chapter, we present how to apply the RT-PCR technique, protocols for its performance, experimental set-up and softwar…

Recurrence Quantification Analysis as a Methodological Innovation for School Improvement Research

2021

Contains fulltext : 240653.pdf (Publisher’s version ) (Closed access) School improvement and educational change can be facilitated by learning through reflection, as this allows teachers to discover ways to develop and adapt to change. Higher levels of engagement in reflection have been found to be beneficial, but it is unclear from which everyday routine in engagement in reflection higher levels arise, and thus whether occasions to make knowledge explicit should be organized with a certain constancy. In this study, we therefore used a conceptualization of teacher learning through reflection as a situated and dynamic process in which available environmental information, learning activities,…

Erratum to “Irregularity” [Topology Appl. 154 (8) (2007) 1565–1580]

2012

[2, Proposition 4.4] states that each regular pretopology is topologically regular. Professor F. Mynard (Georgia Southern University) advised the authors that he was not convinced by the proof of that proposition, which enabled us to realize the proposition is wrong, as the example below shows. Recall that (e.g., [2]) a pretopology ξ on a set X is called regular if Vξ (x)⊂ adh ξ Vξ (x) (respectively, topologically regular if Vξ (x)⊂ cl ξ Vξ (x)) for every x ∈ X . As a consequence, in the sequel of [2], regular should be read topologically regular in a few instances, in particular in [2, Theorem 4.6]. [2, Proposition 4.4] is also quoted in [3], where it is used in some reformulations of clas…

Comparison of Iodine Quantification and Conventional Attenuation Measurements for Differentiating Small, Truly Enhancing Renal Masses From High-Atten…

2019

OBJECTIVE. The purpose of this study is to determine whether iodine quantification techniques from contrast-enhanced dual-energy CT (DECT) data allow equal differentiation of small enhancing renal masses from high-attenuation (> 20 HU of unenhanced attenuation) nonenhancing lesions, compared with conventional attenuation measurements. MATERIALS AND METHODS. A total of 220 nonconsecutive patients (mean [± SD] age, 66 ± 13 years; 130 men and 90 women) with 265 high-attenuation renal lesions (mean attenuation, 54 ± 33 HU; 91 enhancing lesions) were included. Each patient underwent single-energy unenhanced CT followed by DECT during the nephrographic phase using one of four different high-en…

2014

In the resurging field of RNA modifications, quantification is a bottleneck blocking many exciting avenues. With currently over 150 known nucleoside alterations, detection and quantification methods must encompass multiple modifications for a comprehensive profile. LC–MS/MS approaches offer a perspective for comprehensive parallel quantification of all the various modifications found in total RNA of a given organism. By feeding 13C-glucose as sole carbon source, we have generated a stable isotope-labeled internal standard (SIL-IS) for bacterial RNA, which facilitates relative comparison of all modifications. While conventional SIL-IS approaches require the chemical synthesis of single modif…

Algorithmic differentiation for cloud schemes (IFS Cy43r3) using CoDiPack (v1.8.1)

2019

Abstract. Numerical models in atmospheric sciences not only need to approximate the flow equations on a suitable computational grid, they also need to include subgrid effects of many non-resolved physical processes. Among others, the formation and evolution of cloud particles is an example of such subgrid processes. Moreover, to date there is no universal mathematical description of a cloud, hence many cloud schemes have been proposed and these schemes typically contain several uncertain parameters. In this study, we propose the use of algorithmic differentiation (AD) as a method to identify parameters within the cloud scheme, to which the output of the cloud scheme is most sensitive. We il…