[Using text mining to identify gap in acquired immunodeficiency syndrome related information dissemination between the official channel delivery and the needs of adolescents].

Objective: The study intends to identify gap in HIV/AIDS awareness dissemination between the official channel delivery and the needs of adolescents. Methods: We crawled all the HIV/AIDS queries from "Baidu zhidao" till June 11st, 2018. "Baidu zhidao" inquiry and information form official public service announcement (abbreviated for "official delivery" hereafter) were the data source for comparative analysis. We categorized the text data into four kinds, "prevention", "testing and treatment", "symptoms and infection" and "legalization and policies" according to official categorization. Word segmentation was used for text mining and word frequency statistics, as well word cloud was used for word frequency visualization (all based on a comparison after removing the useless words). Results: Of the official delivery, the proportion of prevention category accounted for 32.3% (n=162) (ranks 1st), and the proportion of legalization and policies category was 14.1% (n=71). While among the "Baidu zhidao" inquiry information, the proportion of testing and treatment category accounted for 51.7% (n=51 264), and the proportion of prevention category accounted for 11.4% (n=11 272). The frequencies of same terms/ repeated terms of two channels accounted for 60% (59.3%-63.9%) of each category among the official delivery, of which, the proportion of interest terms comparatively less and more diverse in "Baidu zhidao" inquiries. The proportion of the terms frequency of each category was about 45% in "prevention, testing and treatment", 34.3% (n=14 781) in "symptoms and infection" and 17.0% (n=5 744) in "legalization and policies", respectively. Conclusion: A big gap was identified between the available official source and inquiries' term, especially word frequency discrepancy between "legalization and policies" and "prevention" categories. It underscore the necessity for the official channel to address the needs and interests of adolescents in the future.

Cut-off net acid generation pH in predicting acid-forming potential in mine spoils.

Acidification of mine wastes can lead to a series of environmental problems, such as acid drainage, heavy metal mobilization, and ecosystem degradation. Prediction of acid-forming potential is one of the key steps in management of sulfide-bearing mine wastes. In this paper, the acid-forming potential of 180 mine waste samples collected from 17 mine sites in China were studied using a net acid generation (NAG) method. The samples contained different contents of total sulfur (ranging from 0.6 to 200 g kg(-1)), pyritic sulfur (ranging from 0 to 100 g kg(-1)), and acid neutralization capacity (ANC, ranging from -41 to 274 kg H2SO4 t(-1)). Samples with high acid-forming potential are generally due to their high sulfur content or low acid neutralization capacity. After the samples were oxidized by H2O2, the amounts of acid generation and the final NAG pH were measured. Results indicated that the final NAG pH gave a well-defined demarcation between acid-forming and non-acid-forming materials. Samples with final NAG pH >or= 5 could be classified as non-acid-forming materials, while those with NAG pH 2.5, but < 5, had low risk of being acid-forming. The confirmation of cut-off NAG pH will be used as a rapid and cost-effective operational monitoring tool for the in-pit prediction of acid-forming potential of mine wastes and classification of waste types.