Search results for "Mean value"

Latent class identification in wheezing preschool children

2016

Background and aim Since the forced oscillation technique (FOT) has not been used in previous studies on wheezing phenotyping in preschool children, we applied FOT in a large series of outpatients visited at IBIM. Methods We analyzed 256 consecutively enrolled ≤5 years children with doctor diagnosis of wheezing. Latent Class Analysis (LCA) was performed considering the following personal characteristics: type, cause, recurrence in last 12 months, respiratory resistance (Avr_R(8)), atopy, history of eczema, rhinitis and upper airways infections. High resistance is defined as positive residual of regression on sex, age, height and weight. Risk factors were considered meaningful when they yiel…

Profiles and Sources of PAHs in Sediments from an Open-Pit Mining Area in the Peruvian Andes

2015

The Peruvian Andes are one of the most productive areas for mining and therefore also one of the most exposed to these sources of pollution. This article reports the characterization of Polycyclic Aromatic Hydrocarbons (PAHs) in sediments of Cerro de Pasco area (Peru) located close to a large open-pit mine and, in recent years, several reports have provided evidence of environmental contamination and related health problems. Investigations were carried out into the fifteen PAHs identified by the US-Environment Protection Agency (US-EPA) as requiring priority monitoring, other non US-EPA listed PAHs and perylene were also investigated in order to obtain further information on their origins. …

Composition, distribution, and sources of polycyclic aromatic hydrocarbons in sediments of the gulf of Milazzo (Mediterranean Sea, Italy)

2014

This article describes the characterization of Polycyclic Aromatic Hydrocarbons (PAHs) in sediments of Milazzo Gulf (Italy) located in front of an oil refinery and a power plant. The investigated area is characterized by urban and industrial activities. The sixteen PAHs identified by the USEPA, as requiring priority monitoring, and other non USEPA listed PAHs, namely perylene and some methyl derivatives, were investigated The total PAHs concentrations, expressed as ∑ 19 PAH ranges from 5.6–7402 μg/Kg d.w., with a mean value of 492 μg/Kg d.w. The concentrations of PAHs found in 64 out of 67 samples were lower than the effect range low (ERL = 2460 μg/Kg) concentration, while the remaining sam…

Radó–Kneser–Choquet theorem

2014

We present a new approach to the celebrated theorem of Rado–Kneser–Choquet (RKC) on univalence of planar harmonic mappings. The novelty lies in establishing a continuous path (isotopy) from the given harmonic map to a conformal one. Along this path the mappings retain positive Jacobian determinant by virtue of so-called Minimum Principle. These ideas extend to nonlinear uncoupled systems of partial differential equations, as in Iwaniec, Koski and Onninen [‘Isotropic p-harmonic systems in 2D, Jacobian estimates and univalent solutions’, Rev. Mat. Iberoam, to appear]. Unfortunately, details of such digression would lead us too far afield. Nonetheless, one gains (in particular) the RKC-Theorem…

The Second Main Theorem

1998

A Galton–Watson process with a threshold

2016

Abstract In this paper we study a special class of size dependent branching processes. We assume that for some positive integer K as long as the population size does not exceed level K, the process evolves as a discrete-time supercritical branching process, and when the population size exceeds level K, it evolves as a subcritical or critical branching process. It is shown that this process does die out in finite time T. The question of when the mean value E(T) is finite or infinite is also addressed.

A Bayesian analysis of a queueing system with unlimited service

1997

Abstract A queueing system occurs when “customers” arrive at some facility requiring a certain type of “service” provided by the “servers”. Both the arrival pattern and the service requirements are usually taken to be random. If all the servers are busy when customers arrive, they usually wait in line to get served. Queues possess a number of mathematical challenges and have been mainly approached from a probability point of view, and statistical analysis are very scarce. In this paper we present a Bayesian analysis of a Markovian queue in which customers are immediately served upon arrival, and hence no waiting lines form. Emergency and self-service facilities provide many examples. Techni…

Characteristic Functions and the Central Limit Theorem

2020

The main goal of this chapter is the central limit theorem (CLT) for sums of independent random variables (Theorem 15.37) and for independent arrays of random variables (Lindeberg–Feller theorem, Theorem 15.43). For the latter, we prove only that one of the two implications (Lindeberg’s theorem) that is of interest in the applications.

Peak capacity estimation in isocratic elution.

2008

Peak capacity (i.e. maximal number of resolved peaks that fit in a chromatographic window) is a theoretical concept with growing interest, but based on a situation rarely met in practice. Real chromatograms tend to have uneven distributions, with overlapped peaks and large gaps. The number of resolved compounds should, therefore, be known from estimations. Several equations have been reported for this purpose based on three perspectives, namely, the intuitive approach (peak capacity as the size of the retention time window measured in peak width units), which assumes peaks with the same width, and the outlines of Giddings and Grushka, which consider changes in peak width with retention time…

Tooth discoloration and internal bleaching after the use of ledermix paste with various bleaching agents ? An in vitro study

2018

Background To assess the reversal of discolouration caused by Ledermix using various bleaching agents. Material and Methods Twenty six extracted human mandibular premolars were taken and divided into four groups. Six teeth were divided into three each which are taken as positive and negative controls. The remaining twenty are divided into two groups (n=10). After conventional access preparation, the Ledermix paste was sealed in the pulp chamber for twelve weeks. The paste was removed by a rinse with sodium hypochlorite (NaOCl). Then the pulp chamber was sealed with a mixture of Sodium perborate and distilled water for group 1 and group 2 was sealed with Sodium tetraborate for 1 to 12 weeks.…