Examining the Oxidation States of Metals in Aerosols Emitted by Electronic Cigarettes.

Electronic cigarettes (ECs) emit many toxic substances, including metals, that can pose a threat to users and the environment. The toxicity of the emitted metals depends on their oxidation states. Hence, this study examines the oxidation states of metals observed in EC aerosols. X-ray photoelectron spectroscopy analysis of the filters that collected EC aerosols identified the oxidation states of five primary metals (based on surface sample analysis), including chromium(III) (close to 100%) under low power setting while a noticeable amount of chromium(VI) (15%) at higher power settings of the EC, and copper(II) (100%), zinc(II) (100%), nickel(II) (100%), lead(II) (65%), and lead(IV) (35%) regardless of power settings. This observation indicates that the increased temperature due to higher power settings could alter the oxidation states of certain metals. We noted that many metals were in their lesser toxic states; however, inhaling these metals may still pose health risks.

Soil erosion modelling: A bibliometric analysis.

Soil erosion can present a major threat to agriculture due to loss of soil, nutrients, and organic carbon. Therefore, soil erosion modelling is one of the steps used to plan suitable soil protection measures and detect erosion hotspots. A bibliometric analysis of this topic can reveal research patterns and soil erosion modelling characteristics that can help identify steps needed to enhance the research conducted in this field. Therefore, a detailed bibliometric analysis, including investigation of collaboration networks and citation patterns, should be conducted. The updated version of the Global Applications of Soil Erosion Modelling Tracker (GASEMT) database contains information about citation characteristics and publication type. Here, we investigated the impact of the number of authors, the publication type and the selected journal on the number of citations. Generalized boosted regression tree (BRT) modelling was used to evaluate the most relevant variables related to soil erosion modelling. Additionally, bibliometric networks were analysed and visualized. This study revealed that the selection of the soil erosion model has the largest impact on the number of publication citations, followed by the modelling scale and the publication's CiteScore. Some of the other GASEMT database attributes such as model calibration and validation have negligible influence on the number of citations according to the BRT model. Although it is true that studies that conduct calibration, on average, received around 30% more citations, than studies where calibration was not performed. Moreover, the bibliographic coupling and citation networks show a clear continental pattern, although the co-authorship network does not show the same characteristics. Therefore, soil erosion modellers should conduct even more comprehensive review of past studies and focus not just on the research conducted in the same country or continent. Moreover, when evaluating soil erosion models, an additional focus should be given to field measurements, model calibration, performance assessment and uncertainty of modelling results. The results of this study indicate that these GASEMT database attributes had smaller impact on the number of citations, according to the BRT model, than anticipated, which could suggest that these attributes should be given additional attention by the soil erosion modelling community. This study provides a kind of bibliographic benchmark for soil erosion modelling research papers as modellers can estimate the influence of their paper.

Soil erosion modelling: A global review and statistical analysis.

To gain a better understanding of the global application of soil erosion prediction models, we comprehensively reviewed relevant peer-reviewed research literature on soil-erosion modelling published between 1994 and 2017. We aimed to identify (i) the processes and models most frequently addressed in the literature, (ii) the regions within which models are primarily applied, (iii) the regions which remain unaddressed and why, and (iv) how frequently studies are conducted to validate/evaluate model outcomes relative to measured data. To perform this task, we combined the collective knowledge of 67 soil-erosion scientists from 25 countries. The resulting database, named 'Global Applications of Soil Erosion Modelling Tracker (GASEMT)', includes 3030 individual modelling records from 126 countries, encompassing all continents (except Antarctica). Out of the 8471 articles identified as potentially relevant, we reviewed 1697 appropriate articles and systematically evaluated and transferred 42 relevant attributes into the database. This GASEMT database provides comprehensive insights into the state-of-the-art of soil- erosion models and model applications worldwide. This database intends to support the upcoming country-based United Nations global soil-erosion assessment in addition to helping to inform soil erosion research priorities by building a foundation for future targeted, in-depth analyses. GASEMT is an open-source database available to the entire user-community to develop research, rectify errors, and make future expansions.

Comprehensive Knowledge of HIV and AIDS among Ghanaian Adults from 1998 to 2014: A Multilevel Logistic Regression Model Approach.

BACKGROUND: In order for stakeholders of HIV and AIDS to effectively plan HIV prevention programs, it is expedient to assess the level of individuals' knowledge on the most common preventive methods and misconceptions of the HIV virus. This study examines the trends and determinants of comprehensive knowledge (CK) of HIV and AIDS among Ghanaians from 1998-2014. METHOD: The data used for this study were drawn from the Ghana Demographic Health Surveys (GDHS), 1998-2014. A separate analysis was performed on each survey-year data and GDHS pooled dataset. Additionally, both the male and female datasets were combined. The samples used for the study were 6,389, 10706, 9484, and 13784 representing 1998, 2003, 2008, and 2014, respectively. The pooled dataset consisted of 40363 responses. The Pearson chi-square test and multilevel binary logistic regression analysis were carried out to assess the association between the study variables and CK of HIV and AIDS. RESULTS: CK of HIV and AIDS was found to be lower in women than men (29.24% vs. 37.7%) using the pooled dataset. The Greater Accra region recorded the highest percentage of CK of HIV and AIDS (44.18%), whereas the Northern region recorded the lowest (17.87%) among the 10 administrative regions in Ghana. Comprehensive knowledge of HIV and AIDS was also found to be less likely with an OR of 0.72 (95% CI; 0.65, 0.79, p < 0.001) among persons living in rural areas even after controlling for other study variables. There is also a decrease of CK of HIV and AIDS from 37.35% in 2008 to 32.5% in 2014. The lowest percentage (10.75%) of CK of HIV and AIDS among the four survey years was recorded in 1998. CONCLUSION: There are generally low levels of comprehensive knowledge among the Ghanaian adult population more especially among women. Those residing in rural areas have lower prevalence of CK of HIV and AIDS. To address some of these challenges, there is the need to intensify educational interventions more especially among women and people leaving in rural areas to reverse some of the knowledge gaps and correct the local misconceptions of HIV and AIDS.