Search results for " quality"
showing 10 items of 3133 documents
Repeatability of in-vitro optical quality measurements of intraocular lenses with a deflectometry technique effect of the toricity
2018
Aim To evaluate the repeatability of an optical device for measuring the Zernike coefficients of toric intraocular lenses (IOLs) and assess whether its toricity has any impact in its repeatability. Methods An experienced technician used the NIMO TR1504 to measure the Zernike coefficients 30 times for an aperture of 4.50 mm for all lenses included. The IOLs included were divided into two group: toric and non-toric ones. The cylindrical powers of the toric lenses included in the present study were 1.00, 1.50, 2.25, 3.00 and 3.75 D. Finally, the repeatability of the NIMO TR1504 was described in terms of within subject standard deviation (Sw) and repeatability limit. Results The Sw was smaller …
Intercomparison of methods to estimate gross primary production based on CO2 and COS flux measurements
2022
Separating the components of ecosystem-scale carbon exchange is crucial in order to develop better models and future predictions of the terrestrial carbon cycle. However, there are several uncertainties and unknowns related to current photosynthesis estimates. In this study, we evaluate four different methods for estimating photosynthesis at a boreal forest at the ecosystem scale, of which two are based on carbon dioxide (CO2) flux measurements and two on carbonyl sulfide (COS) flux measurements. The CO2-based methods use traditional flux partitioning and artificial neural networks to separate the net CO2 flux into respiration and photosynthesis. The COS-based methods make use of a unique 5…
Impacts and adaptation options of climate change on ecosystem services in Finland: a model based study
2013
At a global level, it is estimated that nearly two-thirds of ecosystem services have been degraded in just fifty years. The additional stresses imposed by climate change will require extraordinary adaptation. This paper synthesises main result of a large Finnish project studying the vulnerability of key ecosystem services to climate change and the possibilities for the individual sectors to adapt to these changes. The project based its work on data and infrastructures of nine intensively studied areas belonging to the Finnish LTER (Long-Term Ecological Research) network. The methods developed and used included remote sensing, derivation of impact scenarios, dynamic modelling, laboratory exp…
The impact of urban development on aquifers in large coastal cities of West Africa: Present status and future challenges
2018
Abstract This paper investigates the coastal cities of Abidjan, Cotonou, Lagos and Douala in West Africa. Published data on these areas were aggregated in order to compare the urban development of some African huge cities and assess their impacts on groundwater. Those urban centers have experienced an exponential demographic expansion since the 1950s, with increased population densities and a geographical coverage expansion as well. The Continental Terminal aquifer, major groundwater resource taped in this region by the national water companies and local populations, shows a continuous downward trend in piezometric levels. Concerning water quality, the evolution up to the current state (sal…
Impact on Air Quality of the COVID-19 Lockdown in the Urban Area of Palermo (Italy).
2020
At the end of 2019, the first cases of coronavirus disease (COVID-19) were reported in Wuhan, China. Thereafter, the number of infected people increased rapidly, and the outbreak turned into a national crisis, with infected individuals all over the country. The COVID-19 global pandemic produced extreme changes in human behavior that affected air quality. Human mobility and production activities decreased significantly, and many regions recorded significant reductions in air pollution. The goal of our investigation was to evaluate the impact of the COVID-19 lockdown on the concentrations of the main air pollutants in the urban area of Palermo (Italy). In this study, the trends in the average…
Building a statistical surveillance dashboard for COVID-19 infection worldwide
2020
When a pandemic like the current novel coronavirus (COVID-19) breaks out, it is important that authorities, healthcare organizations and official decision makers, have in place an effective monitoring system to promptly analyze data, create new insights into problematic areas and generate actionable knowledge for fact-based decision making. The aim of this article is to describe an initial work focused on building a comprehensive statistical surveillance dashboard for the epidemic of COVID-19, which can be exploited also for future needs. We propose novel ways of exploring, analyzing and presenting data, using metrics that have not been used previously. We also show the steps necessary to b…
Effects of the COVID-19 Pandemic on Sports Entrepreneurship
2020
Sports entrepreneurship has been considered an important part of sports organisations when overcoming crisis situations. The aim of this study is to determine the impact of the crisis derived from COVID-19 on sports entrepreneurship and whether there are differences in the prediction of entrepreneurship on service quality in non-profit sports clubs. To this end, 145 sports clubs were analysed before and after the outbreak of the virus in society. Paired sample-t tests were carried out to determine the differences in variables studied before (Time I) and after (Time II) the COVID-19 outbreak, and correlations and hierarchical linear regressions were used to analyse the relationship between t…
An experimental search for a correlation between outdoor 222Rn concentration and 210Pb activity in air particulate samples
2018
This work was aimed to search for a correlation between outdoor 222Rn air concentration and 210Pb activity in particulate samples collected on a filter. The existence of a correlation could support the hypothesis that both 222Rn and its long-lived product 210Pb are embedded into the same air masses and undergo the same air transport phenomena. Lead-210 activity was determined by means of gamma ray spectrometric measurement carried out a few days after the sampling whereas 222Rn concentration was measured through a commercial monitor. Experimental tests allowed to obtain a weak correlation between 222Rn and 210Pb air concentration as a preliminary result due to high uncertainties of outdoor …
Menstrual problems and lifestyle among Spanish university women
2020
Menstrual problems affect many young women worldwide, conditioning both their academic performance and quality of life. This study sought to analyse the prevalence of menstrual problems and their possible relationship with lifestyle among Spanish university women, as part of a research project (UniHcos Project) involving a cohort of 11 Spanish universities with 7208 university students. A descriptive analysis was performed using the bivariate chi-square test and the Student&rsquo
Processing of 3D Models for Networking of CH in Geomatics
2020
In recent times the possibility of reconstruction of complex 3D Cultural Heritage (CH) environments has opened new scenarios for touristic and scientific aims. The different needs for networking or conservation purposes of CH lead to study proper structuring of 3D models. In light of this, a scientific approach has been developed in order to test the networking capabilities, comparing different loading configurations of 3D environments with multiple combinations of 3D models inside them, considering different solutions. This experimentation has been based on WebGL-HTML5 technologies and allowed to discover the true balance between performances of proposed system, the quality of visualizatio…