Investigating the quality of modeled aerosol profiles based on combined lidar and sunphotometer data

In this study we present an evaluation of the Comprehensive Air Quality Model with extensions (CAMx) for Thessaloniki using radiometric and lidar data. The aerosol mass concentration profiles of CAMx are compared against the PM2.5 and PM2. 5−10 concentration profiles retrieved by the Lidar-Radiometer Inversion Code (LIRIC). The CAMx model and the LIRIC algorithm results were compared in terms of mean mass concentration profiles, center of mass and integrated mass concentration in the boundary layer and the free troposphere. The mean mass concentration comparison resulted in profiles within the same order of magnitude and similar vertical structure for the PM2. 5 particles. The mean centers of mass values are also close, with a mean bias of 0.57 km. On the opposite side, there are larger differences for the PM2. 5−10 mode, both in the boundary layer and in the free troposphere. In order to grasp the reasons behind the discrepancies, we investigate the effect of aerosol sources that are not properly included in the model's emission inventory and in the boundary conditions such as the wildfires and the desert dust component. The identification of the cases that are affected by wildfires is performed using wind backward trajectories from the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model in conjunction with satellite fire pixel data from MODerate-resolution Imaging Spectroradiometer (MODIS) Terra and Aqua global monthly fire location product MCD14ML. By removing those cases the correlation coefficient improves from 0.69 to 0.87 for the PM2. 5 integrated mass in the boundary layer and from 0.72 to 0.89 in the free troposphere. The PM2.5 center of mass fractional bias also decreases to 0.38 km. Concerning the analysis of the desert dust component, the simulations from the Dust Regional Atmospheric Model (BSC-DREAM8b) were deployed. When only the Saharan dust cases are taken into account, BSC-DREAM8b generally outperforms CAMx when compared with LIRIC, achieving a correlation of 0.91 and a mean bias of −29.1 % for the integrated mass in the free troposphere and a correlation of 0.57 for the center of mass. CAMx, on the other hand, underestimates the integrated mass in the free troposphere. Consequently, the accuracy of CAMx is limited concerning the transported Saharan dust cases. We conclude that the performance of CAMx appears to be best for the PM2.5 particles, both in the boundary layer and in the free troposphere. Sources of particles not properly taken into account by the model are confirmed to negatively affect its performance, especially for the PM2. 5−10 particles.The authors would like to acknowledge the EU projects MACC-III (Monitoring Atmospheric Composition and Climate – III, grant agreement no. 633080) and MACC-II project (Monitoring Atmospheric Composition and Climate – Interim Implementation, grant agreement no. 283576). The simulated results presented in this research paper have been produced using the EGI and HellasGrid infrastructures. The ACTRIS-2 project from the European Union’s Horizon 2020 research and innovation programme under grant agreement no. 654109 is gratefully acknowledged. The authors would also like to acknowledge the support provided by the Scientific Computing Center at Aristotle University of Thessaloniki throughout the progress of the work on air quality forecasting. BSC-DREAM8b simulations were performed on the Mare Nostrum supercomputer hosted by Barcelona Supercomputing Center-Centro Nacional de Supercomputacion (BSC-CNS). S. Basart wants to acknowledge the CICYT project (CGL2013-46736). Elina Giannakaki acknowledges the support of the Academy of Finland (project no. 270108).Peer ReviewedPostprint (published version

EARLINET: 12-year of aerosol profiling over Europe

EARLINET has been collecting high quality aerosol optical profiles over Europe since 2000. The comparison with automatic collected dataset of aerosol optical depth (AOD) from AERONET and MODIS demonstrates the effectiveness of EARLINET regular measurement schedule for climatological studies. The analysis of optical properties in the local boundary layer indicates that the general decrease of AOD observed by different platforms over Europe in the last decade could be due to the modification of aerosol properties (towards less absorbing and larger particles) in the lower troposphere

Psychometric evaluation of the nine-item problematic Internet use questionnaire (PIUQ-9) in nine European samples of internet users

Objectives: The nine-item Problematic Internet Use Questionnaire (PIUQ-9) is a brief self-report screening instrument for problematic internet use. The main objective of the present study was to explore the psychometric properties of the PIUQ-9 among nine different language-based samples of European internet users (Italian, German, French, Polish, Turkish, Hungarian, English, and Greek). Methods: The total sample comprised 5,593 internet users (38.1% men), aged between 18 and 87 years (M = 25.81; SD = 8.61). Via online recruitment, participants completed the PIUQ-9, the Brief Symptom Inventory (BSI) and items about time spent online. Results: Confirmatory factor analysis demonstrated that the bifactor model with one general factor (i.e., general problem) and two-specific factors (i.e., obsession and neglect + control disorder) yielded acceptable or good fit indices in all subsamples except for one. The common variance index in the bifactor model indicated that the general problem factor explained from 57.0 to 76.5% of common variance, which supports the presence of a strong global factor. According to the multiple indicators multiple causes (MIMIC) model, psychiatric symptoms had a moderate-to-strong direct effect on the general problem factor in all subsamples, ranging from β = 0.28 to β = 0.52 supporting the construct validity of the scale. Furthermore, in a majority of the subsamples, time spent online during the weekend had considerably higher effect sizes on the general problem factor than time spent online during weekdays. Conclusion: The present study highlights the appropriate psychometric properties of the PIUQ-9 across a number of European languages and cultures

A methodology for investigating dust model performance using synergistic EARLINET/AERONET dust concentration retrievals

Systematic measurements of dust concentration profiles at a continental scale were recently made possible by the development of synergistic retrieval algorithms using combined lidar and sun photometer data and the establishment of robust remote-sensing networks in the framework of Aerosols, Clouds, and Trace gases Research Infra-Structure Network (ACTRIS)/European Aerosol Research Lidar Network (EARLINET). We present a methodology for using these capabilities as a tool for examining the performance of dust transport models. The methodology includes considerations for the selection of a suitable data set and appropriate metrics for the exploration of the results. The approach is demonstrated for four regional dust transport models (BSC-DREAM8b v2, NMMB/BSC-DUST, DREAM-ABOL, DREAM8-NMME-MACC) using dust observations performed at 10 ACTRIS/EARLINET stations. The observations, which include coincident multi-wavelength lidar and sun photometer measurements, were processed with the Lidar-Radiometer Inversion Code (LIRIC) to retrieve aerosol concentration profiles. The methodology proposed here shows advantages when compared to traditional evaluation techniques that utilize separately the available measurements such as separating the contribution of dust from other aerosol types on the lidar profiles and avoiding model assumptions related to the conversion of concentration fields to aerosol extinction values. When compared to LIRIC retrievals, the simulated dust vertical structures were found to be in good agreement for all models with correlation values between 0.5 and 0.7 in the 1-6 km range, where most dust is typically observed. The absolute dust concentration was typically underestimated with mean bias values of -40 to -20 mu g m(-3) at 2 km, the altitude of maximum mean concentration. The reported differences among the models found in this comparison indicate the benefit of the systematic use of the proposed approach in future dust model evaluation studies

Internet addiction, fatigue, and sleep problems among adolescent students: a large-scale study

Aim: The aim of the present study was to examine the association between Internet Addiction (IA), fatigue, and sleep problems among university students. Methods: A total of 3,000 Turkish students aged 18 to 25 years were approached and 2,350 students (78.3%) participated in this cross-sectional study from April 2017 to September 2017 in public and private universities in Istanbul. Data were collected via a structured questionnaire including socio-demographic details, lifestyle and dietary habits, Internet Addiction Test (IAT), Fatigue Scale, and Epworth Sleepiness Scale [ESS]. Descriptive statistics, multivariate and factorial analyses were performed. Results: The overall prevalence of IA among the studied population was 17.7%. There were significant differences between gender, family income, father’s occupation, school performance, frequency and duration of watching television, physical activity, internet use duration, and sleep duration (all p<0.001). Significant differences were also found between participants with IA and those without IA in having headaches, blurred vision, double vision, hurting eyes, hearing problems, and eating fast food frequently (all p<0.001). Using multivariate regression analysis, the duration of internet use, physical and mental symptoms, headache, hurting eyes, tired eyes, hearing problems and ESS scores were significantly associated with (and primary predictors of) IA. Conclusion: The present study demonstrated that IA was associated with poor dietary habits, sleep problems, and fatigue symptoms

Internet addiction: a 21st century epidemic?

Internet addiction, while not yet officially codified within a psychopathological framework, is growing both in prevalence and within the public consciousness as a potentially problematic condition with many parallels to existing recognized disorders. The rapid and unfettered increase in the number of people accessing a relatively unrestricted internet substantially increases the possibility that those suffering with an underlying psychological comorbidity may be at serious risk of developing an addiction to the internet, lending further credence to this hitherto understudied condition. In this commentary, I outline my recommendations for improved diagnosis, study and prevention of internet addiction

The Radially Swollen 4 Separase Mutation of Arabidopsis thaliana Blocks Chromosome Disjunction and Disrupts the Radial Microtubule System in Meiocytes

The caspase-family protease, separase, is required at the onset of anaphase to cleave the cohesin complex that joins replicated sister chromatids. However, in various eukaryotes, separase has acquired additional and distinct functions. A single amino-acid substitution in separase is responsible for phenotypes of the Arabidopsis thaliana mutant, radially swollen 4 (rsw4). This is a conditional mutant, resembling the wild type at the permissive temperature (∼20°C) and expressing mutant phenotypes at the restrictive temperature (∼30°C). Root cells in rsw4 at the restrictive temperature undergo non-disjunction and other indications of the loss of separase function. To determine to what extent separase activity remains at 30°C, we examined the effect of the mutation on meiosis, where the effects of loss of separase activity through RNA interference are known; and in addition, we examined female gametophyte development. Here, we report that, at the restrictive temperature, replicated chromosomes in rsw4 meiocytes typically fail to disjoin and the cohesin complex remains at centromeres after metaphase. Meiotic spindles appear normal in rsw4 male meiocytes; however the mutation disrupts the radial microtubule system, which is replaced by asymmetric arrays. Surprisingly, female gametophyte development was relatively insensitive to loss of separase activity, through either rsw4 or RNAi. These effects confirm that phenotypes in rsw4 result from loss of separase activity and establish a role for separase in regulating cell polarization following male meiosis

The problematic use of Information and Communication Technologies (ICT) in adolescents by the cross sectional JOITIC study

Background: The emerging field of Information and Communications Technology (ICT) has brought about new interaction styles. Its excessive use may lead to addictive behaviours. The objective is to determine the prevalence of the problematic use of ICT such as Internet, mobile phones and video games, among adolescents enrolled in mandatory Secondary Education (ESO in Spanish) and to examine associated factors. Methods: Cross sectional, multi-centric descriptive study. Population: 5538 students enrolled in years one to four of ESO at 28 schools in the Vallès Occidental region (Barcelona, Spain). Data collection: self-administered socio-demographic and ICT access questionnaire, and validated questionnaires on experiences related to the use of the Internet, mobile phones and video games (CERI, CERM, CERV). Results: Questionnaires were collected from 5,538 adolescents between the ages of 12 and 20 (77.3 % of the total response), 48.6 % were females. Problematic use of the Internet was observed in 13.6 % of the surveyed individuals; problematic use of mobile phones in 2.4 % and problematic use in video games in 6.2 %. Problematic Internet use was associated with female students, tobacco consumption, a background of binge drinking, the use of cannabis or other drugs, poor academic performance, poor family relationships and an intensive use of the computer. Factors associated with the problematic use of mobile phones were the consumption of other drugs and an intensive use of these devices. Frequent problems with video game use have been associated with male students, the consumption of other drugs, poor academic performance, poor family relationships and an intensive use of these games. Conclusions: This study offers information on the prevalence of addictive behaviours of the Internet, mobile phones and video game use. The problematic use of these ICT devices has been related to the consumption of drugs, poor academic performance and poor family relationships. This intensive use may constitute a risk marker for ICT addictio

The screens culture: impact on ADHD

Children’s use of electronic media, including Internet and video gaming, has increased dramatically to an average in the general population of roughly 3 h per day. Some children cannot control their Internet use leading to increasing research on “internet addiction.” The objective of this article is to review the research on ADHD as a risk factor for Internet addiction and gaming, its complications, and what research and methodological questions remain to be addressed. The literature search was done in PubMed and Psychinfo, as well as by hand. Previous research has demonstrated rates of Internet addiction as high as 25% in the population and that it is addiction more than time of use that is best correlated with psychopathology. Various studies confirm that psychiatric disorders, and ADHD in particular, are associated with overuse, with severity of ADHD specifically correlated with the amount of use. ADHD children may be vulnerable since these games operate in brief segments that are not attention demanding. In addition, they offer immediate rewards with a strong incentive to increase the reward by trying the next level. The time spent on these games may also exacerbate ADHD symptoms, if not directly then through the loss of time spent on more developmentally challenging tasks. While this is a major issue for many parents, there is no empirical research on effective treatment. Internet and off-line gaming overuse and addiction are serious concerns for ADHD youth. Research is limited by the lack of measures for youth or parents, studies of children at risk, and studies of impact and treatment