Search results for "ample"
showing 10 items of 2398 documents
Estrategias para la elaboración de modelos estadísticos de regresión
2011
Multivariable regression models are widely used in health science research, mainly for two purposes: prediction and effect estimation. Various strategies have been recommended when building a regression model: a) use the right statistical method that matches the structure of the data; b) ensure an appropriate sample size by limiting the number of variables according to the number of events; c) prevent or correct for model overfitting; d) be aware of the problems associated with automatic variable selection procedures (such as stepwise), and e) always assess the performance of the final model in regard to calibration and discrimination measures. If resources allow, validate the prediction mo…
The impact of embassies and consulates on tourism
2007
Abstract This paper estimates the effect of embassies and consulates on tourist flows from the G-7 countries. The results indicate that embassies and consulates have a positive and significant effect on tourism that ranges between 15% and 30% depending on the estimation technique. Moreover, the impact is larger for the sample of developing countries. The disaggregated analysis shows that, after controlling for both origin and destination fixed effects, a significant impact is found in the seven origin countries.
Crash modeling for urban roundabouts: a case study
2013
In many cities and towns, a large number of intersections are considered sites with promise for safety and operational improvements. Several studies have been carried out in many countries to establish relationships between crashes and flow and non-flow explanatory variables, using statistical tools to investigate factors critical to road safety. Starting from a brief review of existing information and analysis on the issue, this article summarizes the findings of an exploratory analysis aimed at modeling injury crashes for a sample of urban roundabouts. The methodological path followed in this research allowed to handle issues associated with the estimation of a safety performance function…
Sample details on OSL data for aeolian sediments in north-eastern part of European Sand Belt
2019
A compilation of previously published and unpublished absolute age (OSL and TL) determinations of aeolian sediments from the north-eastern part of European Sand Belt. Contains age, error, sampling depth, location etc. and a reference to data source. Coordinates of sampling locations for contemporary publications are taken from field observations (GPS), but older ones - published schematic maps. Data set is created according to schema of DATED-1 database (https://doi.org/10.1594/PANGAEA.848117).
Micellar electrokinetic chromatography of polyamines and monoacetylpolyamines
2001
A selective procedure for qualitative and quantitative analysis of ten polyamines by micellar electrokinetic chromatography (MEKC) was developed. Benzoylated polyamines and acetylpolyamines in micellar phase of SDS (10 mM) were separated at 25 degrees C by 20 mM borate buffer pH 8.5, containing 8% ethanol, with an applied voltage of 25 kV (5 microA) and then detected at 198 nm. The experimental factors and operational parameters were optimized by performing analysis at different surfactant concentrations, pH, voltage and temperature with and without ethanol. The repeatibility of migration times and peak heights is a peculiarity of the method here described.
Successful principalship in Norway: sustainable ethos and incremental changes?
2009
PurposeThe purpose of this paper is to explore whether and how success has been sustained over time in schools which were identified as being successful five years ago.Design/methodology/approachThree schools were selected for a revisit, and the sample included two combined schools (grade 1‐10) and one upper secondary school (grade 11‐13). In two schools the same principals were still in post, and in the third school there had recently been a change in principalship. Interviews with the principal and a group of teachers at each school were the major source of new data. Questions that guided the study: What structural and cultural changes can be identified within the schools compared with fi…
Export Price Discrimination in Europe and Exchange Rates
2002
The paper studies pricing-to-market behavior on a wide range of disaggregated European Union exports to OECD countries. The sample allows better identification of products for which such behavior is pervasive. The results suggest that the degree of markup adjustment in response to exchange rate changes is similar across destination markets. The evidence of pricing-to-market across source countries ranges from 40% (Netherlands) to 63% (Germany) of the products in the sample, except for the United Kingdom, where there is remarkably little evidence of it. However, formal comparisons across source countries by product do not usually reveal differences in behavior.
Asymmetry of CEO Compensation and the Role of Relative and Macroeconomic Shocks in Risk Taking Incentives
2015
If managers are risk-averse and compensation schemes are not directly linked to shareholder wealth, incentives to allocate effort to manage effects of relative and macroeconomic shocks may be distorted. In this paper we develop a simple model to identify factors that determine the optimal allocation of effort to manage relative and macroeconomic shocks. We then show how serial correlation in shocks, the relative variance of shocks and the ability of managers to influence the effects of shocks on shareholder wealth determine the optimal allocation of managerial effort. Thereafter, we emphasize how CEO compensation depends on performance variables distinguishing between relative and macroecon…
Exemplification and Exemplars, Effects of
2008
The term “exemplification effect” describes the influence of illustrating and aggregating case descriptions in media presentations on the recipients' perceptions of issues. Aggregating case descriptions emerges whenever media coverage presents any kind of generalizing claim about natural or social phenomena and an arbitrarily selected sample of single cases to illustrate the issue at hand. General claims (e.g., “growing poverty in society”) often are supported by presenting quantitative information (so-called “base-rate information”) about a large number of cases (e.g., statistics about poverty; Statistics, Descriptive). Keywords: Communication Reception and Effects; Persuasion and Social …
Exopeptidase digestion in combination with field desorption mass spectrometry for amino acid sequence determination
1982
Numerous studies have been devoted in the last years to the development of mass spectrometric methods for the sequence determination of peptides [ 1,2]. Most advanced among this work has been so far the rigorous chemical derivatization of oligopeptides to achieve sufficient volatility for the application of conventional (electron impact, EI) mass spectrometry [2-41. For example, the analysis by gas chromatography-mass spectrometry (GC-MS) of mixtures of oligopeptide fragments derivatized after chemical or enzymatic hydrolysis of polypeptides has been successfully used for sequence determinations [2,5]. Major limitations of this approach are that only small peptide derivatives are amenable t…