Search results for "ample"
showing 10 items of 2398 documents
Norm values for eosinophil cationic protein in nasal secretions: influence of specimen collection
1999
Background Eosinophil granulocytes play an important role in allergic inflammation of the nasal mucosa. Eosinophil cationic protein (ECP) is a specific eosinophil granule protein released upon activation of these cells. ECP concentration in nasal secretions has been demonstrated to be a good marker for the activity of eosinophilic nasal mucosal inflammation. The clinical use of such a marker requires defined values which are regarded as pathological or within normal range. In analyses of nasal secretion samples, the sampling method has an important influence on the data obtained. Objective We investigated ECP levels in nasal secretions (NS) of healthy volunteers obtained by seven different …
Derivatization of ephedrine with o-phthaldialdehyde for liquid chromatography after treatment with sodium hypochlorite.
2000
The usefulness of the reaction with NaClO followed by derivatization with o-phthaldialdehyde (OPA) and N-acetyl-L-cysteine (NAC) has been investigated for the chromatographic analysis of ephedrine. The influence of parameters affecting the two-stage reaction has been evaluated, including concentration of NaClO, time of reaction, temperature and pH. On the basis of these studies, conditions for the pre-column and (automated) post-column determination of ephedrine are presented. The described conditions have been applied to the measurement of ephedrine in the concentration intervals 0.2-20.0 microg/ml and 2.0-50.0 microg/ml for the pre-column and post-column methods, respectively. The possibi…
Questionnaires and simulations to assess daylighting in Italian university classrooms for IEQ and energy issues
2021
Abstract Results from the DAYKE-Italy project are presented. An investigation on daylighting in eight classrooms in five Italian universities was carried out through a combined approach: an ad-hoc survey administered to students to investigate how they perceive daylight in classroom, and numerical simulations (DIVA + ALFA) to calculate a set of objective metrics (daylight, circadian, and energy-related). A sample of 542 questionnaires was collected through two sessions and the subjective judgments were correlated to objective metrics. Results from descriptive and statistical analyses showed: (i) the correlation was significant for all daylight metrics: among them, average daylight factor an…
Rheological blood behaviour is not related to gender in morbidly obese subjects.
2012
To the Editor. We have read with interest the recently published article by Wiewiora et al. [7] regarding hemorheological differences related to gender in morbidly obese subjects. In this study authors found several hemorheological differences between male and female. In this sense, males showed higher blood viscosity and higher erythrocyte deformability than females and native blood viscosity correlated with several erythrocyte aggregation parameters evaluated with the Laser-Assisted Optical Rotational Cell Analyser (LORCA) [3]. In studies with small sample sizes (18 men and 20 women) there is always the risk that differences in certain variables may appear by chance or by imbalances in th…
A cross-country study of skills and unemployment flows
2021
AbstractUsing an international survey that directly assesses the cognitive skills of the adult population, I study the relation between skills and unemployment flows across 37 countries. Depending on the specifically assessed domain, I document that skills have an unconditional correlation with the log-risk-ratio of exiting to entering unemployment of 0.65–0.68 across the advanced and skill-abundant countries in the sample. The relation is remarkably robust and it is unlikely to be due to reverse causality. I do not find evidence that this positive relation extends to the seven relatively less advanced and less skill-abundant countries in the sample: Peru, Ecuador, Indonesia, Mexico, Chile,…
Estimation de la relation de salaires de Mincer : choix de specification et enjeux économétriques
2012
In the present doctoral thesis, we estimated Mincer’s (1974) semi logarithmic wage function for the French and Pakistani labour force data. This model is considered as a standard tool in order to estimate the relationship between earnings/wages and different contributory factors. Despite of its vide and extensive use, simple estimation of the Mincerian model is biased because of different econometric problems. The main sources of bias noted in the literature are endogeneity of schooling, measurement error, and sample selectivity. We have tackled the endogeneity and measurement error biases via instrumental variables two stage least squares approach for which we have proposed two new instrum…
Valuing public acceptance of alternative-fuel buses using a Latent Class Tobit model: A case study in Valencia
2020
Abstract The introduction of hybrid electric technology for urban public transportation can be considered a valuable stepping stone to low-carbon mobility. Using the contingent valuation method, a sample of 427 respondents were asked about their willingness to pay for the air pollution reductions associated to a scenario of gradual introduction of hybrid electric buses in Valencia, Spain. Results show that 67% of the respondents are willing to pay extra for the adoption of this electric hybrid technology, being the mean willingness to pay € 0.33 per single bus fare. This would imply a 22% hypothetical increase in current bus fares and shows that public acceptance is critical for the success…
Comparing Different Estimation Methodologies of Regional GDPs in Latin American Countries
2020
This chapter presents a survey of the different methods used to reconstitute long-run income estimations for the Latin American regions. The main purpose is to alert on potential biases derived from them. Although the bottom-up approaches based on the direct estimation of aggregate production, income or expenditure are the preferred option, they have barely been used. The main reason is that all of them are highly data-demanding. Instead, the indirect non-parametric approaches, combined sometimes with direct estimations for agriculture and extractive industries, have been the most recurrent way to estimate output. Out of the nine countries in the sample, seven have followed this “mixed appr…
Latent segmentation in business-to-business based on information and communication technology and relationship variables
2016
Our work is focused on the segmentation analysis in the Spanish tourist industry. Using a sample of travel agencies who evaluated the relationship with their main supplier (relationship value, relationship benefits and perceived information and communication technologies (ICTs) use), we attempt to examine the utility of these variables as specific and subjective segmentation criteria for identifying heterogeneous groups. The estimation of a finite mixture model suggests that these bases are able to discriminate firms into six latent classes with different levels of ICT use and relationship variables. The novelty in this work lies in the application of latent segmentation methodology and th…
Estimation of ordered response models with sample selection
2011
We introduce two new Stata commands for the estimation of an ordered response model with sample selection. The opsel command uses a standard maximum-likelihood approach to fit a parametric specification of the model where errors are assumed to follow a bivariate Gaussian distribution. The snpopsel command uses the semi-nonparametric approach of Gallant and Nychka (1987, Econometrica 55: 363–390) to fit a semiparametric specification of the model where the bivariate density function of the errors is approximated by a Hermite polynomial expansion. The snpopsel command extends the set of Stata routines for semi-nonparametric estimation of discrete response models. Compared to the other semi-n…