Search results for "Values"
showing 10 items of 1365 documents
A model-based approach for assessing bronchodilator responsiveness in children: The conventional cutoff revisited
2020
An increase in FEV1 >=12% has been proposed in international guidelines as a clue to airway reversibility for diagnosing asthma in both adults and children. However, the validity of this cut-off has been questioned in the pediatric population. The aim of this study was to provide evidence that different cut-off values in BDR may be associated with better performance in discriminating among outpatient children with naïve asthma (A) and without asthma (NA). We compared three approaches: i) the conventional cutoff (12%); ii) the cut-off estimated by Youden's criteria; and iii) the cut-off based on a model-driven approach. we found that the conventional cut-off of 12% showed poor sensitivity in…
Determinants of dynamic inspiratory muscle strength in healthy trained elderly.
2021
Background: The S-Index assessed by means of electronic devices is a measure of Inspiratory Muscle Strength (IMS) that highly correlates with the maximal inspiratory pressure (MIP). The variables involved when using regression models for the prediction of IMS/MIP depend on both the sample characteristics and the device or protocol used. In light of the scarce information on the influence of physical activity (PA) on IMS in healthy older adults (OA), together with the incorporation of new assessment devices, the objectives of this research are: 1) to determine which factors influence the IMS in a group of trained OA, using a portable electronic device; and 2) to propose a regression model to…
Determination of anti GAD65 autoantibodies with an ELISA before and after standardization with the new international reference serum
2009
The serum of a stiff-man syndrome patient was declared international GAD reference standard at the "1st GAD Antibody Workshop" held at the "12th International Immunology and Diabetes Workshop" in Orlando, Florida, USA 1993. A comparative study was performed with 123 diabetic and non-diabetic patients to evaluate whether standardization of this reference serum had changed the properties of a commercially available ELISA assay. All samples classified positive with the old test were confirmed with the new assay. Four additional samples with high "normal" values became positive with the new test. One of them was a control person having a family history of diabetes and genetic loci DR4/DR11. The…
Economic values for production and functional traits in Valle del Belice dairy sheep using profit functions
2011
Abstract A deterministic static model was used to estimate the economic values (EV) of production (MY, milk yield; BW, birth weight; and ADG, average daily gain) and functional traits (ASR, adult survival rate; LSR, lamb survival rate; FE, fertility; PR, prolificacy; and LW ewe , mature weight of ewe) in Valle del Belice dairy sheep. In this study, values for the biological parameters and the production traits used in the model were taken from real data, by surveying 15 Valle del Belice farmers and reflected the production circumstances of pasture based dairy production systems. In this system feed cost accounted for 95% of total variable costs, whereas fixed costs were low and reflected tr…
Tests against stationary and explosive alternatives in vector autoregressive models
2008
. The article proposes new tests for the number of unit roots in vector autoregressive models based on the eigenvalues of the companion matrix. Both stationary and explosive alternatives are considered. The limiting distributions of test statistics depend only on the number of unit roots. Size and power are investigated, and it is found that the new test against some stationary alternatives compares favourably with the widely used likelihood ratio test for the cointegrating rank. The powers are prominently higher against explosive than against stationary alternatives. Some empirical examples are provided to show how to use the new tests with real data.
Vector coherent states and intertwining operators
2009
In this paper we discuss a general strategy to construct vector coherent states of the Gazeau-Klauder type and we use them to built up examples of isospectral hamiltonians. For that we use a general strategy recently proposed by the author and which extends well known facts on intertwining operators. We also discuss the possibility of constructing non-isospectral hamiltonians with related eigenstates.
The rank of random regular digraphs of constant degree
2018
Abstract Let d be a (large) integer. Given n ≥ 2 d , let A n be the adjacency matrix of a random directed d -regular graph on n vertices, with the uniform distribution. We show that the rank of A n is at least n − 1 with probability going to one as n grows to infinity. The proof combines the well known method of simple switchings and a recent result of the authors on delocalization of eigenvectors of A n .
The affine equivariant sign covariance matrix: asymptotic behavior and efficiencies
2003
We consider the affine equivariant sign covariance matrix (SCM) introduced by Visuri et al. (J. Statist. Plann. Inference 91 (2000) 557). The population SCM is shown to be proportional to the inverse of the regular covariance matrix. The eigenvectors and standardized eigenvalues of the covariance, matrix can thus be derived from the SCM. We also construct an estimate of the covariance and correlation matrix based on the SCM. The influence functions and limiting distributions of the SCM and its eigenvectors and eigenvalues are found. Limiting efficiencies are given in multivariate normal and t-distribution cases. The estimates are highly efficient in the multivariate normal case and perform …
Weighted weak semivalues
2000
We introduce two new value solutions: weak semivalues and weighted weak semivalues. They are subfamilies of probabilistic values, and they appear by adding the axioms of balanced contributions and weighted balanced contributions respectively. We show that the effect of the introduction of these axioms is the appearance of consistency in the beliefs of players about the game.
Can the Adaptive Metropolis Algorithm Collapse Without the Covariance Lower Bound?
2011
The Adaptive Metropolis (AM) algorithm is based on the symmetric random-walk Metropolis algorithm. The proposal distribution has the following time-dependent covariance matrix at step $n+1$ \[ S_n = Cov(X_1,...,X_n) + \epsilon I, \] that is, the sample covariance matrix of the history of the chain plus a (small) constant $\epsilon>0$ multiple of the identity matrix $I$. The lower bound on the eigenvalues of $S_n$ induced by the factor $\epsilon I$ is theoretically convenient, but practically cumbersome, as a good value for the parameter $\epsilon$ may not always be easy to choose. This article considers variants of the AM algorithm that do not explicitly bound the eigenvalues of $S_n$ away …