Preferences for pre-exposure prophylaxis for HIV: A systematic review of discrete choice experiments.

Background: We aimed to systematically review the health preference literature using discrete choice experiments (DCEs), an attribute-based stated preference method, to investigate patient preferences for HIV pre-exposure prophylaxis (PrEP).

Methods: A search in PubMed, Scopus, CINAHL, and Embase was conducted on July 1, 2021, and updated on November 3, 2021. We used two concepts to create our search strategy: (1) discrete choice experiments/conjoint analysis/best-worst scaling, and (2) HIV PrEP.

[Dynamic Changes in Hydrochemical Characteristics and Influencing Factors in the Karst Watershed Flood Process].

The hydrochemistry of river water in a karst basin has a rapid response to the rainstorm/flood process, which is an important process of the karst carbon cycle and should not be ignored. Based on the dynamic monitoring of the hydrochemical characteristics of the flood process in the Yangshuo section on November 8-12, 2015, the dynamic change in the main ions and the influencing factors were analyzed, and the concentration and flux of inorganic carbon from different sources were calculated. The results showed that the hydrochemistry types in different stages of the flood area belonged to the Ca-HCO type.

[Fate and Origin of Major Ions in River Water in the Lhasa River Basin, Tibet].

In order to understand the temporal and spatial variations of major ions in water and their sources in the Lhasa River Basin, water samples were collected monthly at the hydrological station in the Lhasa River from August 2014 to July. The results show that HCO is the dominant anion in the water of the Lhasa River, which accounts for 68.73% of the anions, followed by SO.

[Spatial Variation and Environmental Significance of δO and δD Isotope Composition in Xijiang River].

The H and O isotope composition of the Xijiang water was investigated on 54 samples collected from the mainstreams and main tributaries in June 2014 and January 2015.It was found that in the Xijiang river, there was a remarkable linear relationship between δ O and δD. This relationship was more significant in the dry season.

[Hydrochemical Characteristics and Influencing Factors in Different Geological Background: A Case Study in Darongjiang and Lingqu Basin, Guangxi, China].

The observation and sampling were carried out in May 2013 to April 2014 in a hydrological year for two river basins with different geological background in upstream of Li river basin. The seasonal variations of river water chemistry and its main influencing factors were discussed in this paper. The results showed that the hydrochemistry types of both Darongjiang basin with 9% of carbonates and Lingqu basin with nearly 50% of carbonates in area belonged to Ca-HCO3 type.

[Effect of hydrochemistry characteristics under impact of human activity: a case study in the upper reaches of the Xijiang River basin].

In this paper, observation and sampling were taken three times a month in a hydrological year for three typical sections of the middle and upper reaches of the Xijiang River basin, based on the data of hydrochemistry and flow, the article mainly discusses the evolution process of hydrochemistry in river under natural process and impact of human activity. Hydrochemical characteristics of 116. samples were analyzed in the study area.

[Diel variations of hydrochemistry and influencing factors in a surface stream in subtropical karst area, SW China].

In order to understand the diel variation and influencing factors of hydrochemistry in a surface creek fed by karst subterranean river in a subtropical area, where is located at Guancun Village, Daliang Township, Rong'an County of Guangxi Zhuang Autonomous Region, China, two monitoring sites were set simultaneously to launch Guancun subterranean river outlet (G1) and surface creek mouth (G2), respectively. Physical and hydrochemical parameters including pH, dissolved oxygen (DO), water temperature (T) and specific conductivity (Spc) were measured at 15-minute intervals and water samples for analyzing major ions such as Ca2+, HCO3- and NO3- as well as delta3C(DIC) were collected at 2-hour intervals. The results showed that: (1) G1 and G2 sites were both HCO3- Ca type water, however the two monitoring sites showed different diel variations of hydrogeochemical process; (2) The physical and hydrochemical parameters (T, DO, pH, Spc) and major ions (Ca2+, Mg2+, Na+, K+, HCO3-, SO4(2-), NO3-, Cl- in G1 site were basically stable, while the physical and hydrochemical parameters (T, DO, pH, Spc) and major ions (Ca2+, HCO3- and NO3-) in G2 site displayed regular diel variation during monitoring; (3) The dissolved inorganic carbon (DIC) and delta13C values in G2 monitoring site showed reverse characteristics in diurnal fluctuations, where DIC decreased in daylight and increased at night while the delta13C value increased in daylight and decreased at night, DIC also showed a negative correlation with the delta13C value (correlation coefficient is -0.

[Contamination of polycyclic aromatic hydrocarbons in surface water in underground river of Dashiwei Tiankeng group in karst area, Guangxi].

In order to understand the composition, sources and contamination characteristics of PAHs in water from underground river of Dashiwei Tiankeng group in typical karst area located in Leye County, Guangxi. The water samples were collected from different sections to analyze 16 priority polycyclic aromatic hydrocarbons using GC-MS. The results showed that concentration of Sigma PAHs (the total PAHs) in water ranges from 54.