Using Sentinel-2 Imagery and Machine Learning Algorithms to Assess the Inundation Status of Nebraska Conservation Easements during 2018–2021

Conservation easements (CEs) play an important role in the provision of ecological services. This paper aims to use the open-access Sentinel-2 satellites to advance existing conservation management capacity to a new level of near-real-time monitoring and assessment for the conservation easements in Nebraska. This research uses machine learning and Google Earth Engine to classify inundation status using Sentinel-2 imagery during 2018–2021 for all CE sites in Nebraska, USA. The proposed machine learning approach helps monitor the CE sites at the landscape scale in an efficient and low-cost manner. The results confirmed effective inundation performance in these floodplain or wetland-related CE sites. The CE sites under the Emergency Watershed Protection- Floodplain Easement (EWPP-FPE) had the highest inundated area rate of 18.72%, indicating active hydrological inundation in the floodplain areas. The CE sites under the Wetlands Reserve Program (WRP) reached a mean annual surface water cover rate area of 8.07%, indicating the core wetland areas were inundated periodically or regularly. Other types of CEs serving upland conservation purposes had a lower level of inundation while these uplands conservation provided critical needs in soil erosion control. The mean annual surface water cover rate is 0.96% for the CE sites under the Grassland Reserve Program (GRP). The conservation of the CEs on uplands is an important component to reduce soil erosion and improve downstream wetland hydrological inundation performance. The findings support that the sites with higher inundation frequencies can be considered for future wetland-related conservation practices. The four typical wetland-based CE sites suggested that conservation performance can be improved by implementing hydrological restoration and soil erosion reduction at the watershed scale. The findings provided robust evidence to discover the surface water inundation information on conservation assessment to achieve the long-term goals of conservation easements

Modeling impacts of carbon sequestration on net greenhouse gas emissions from agricultural soils in China

Soil organic carbon (SOC) contents in many farmlands have been depleted because of the long-term history of intensive cultivation in China. Chinese farmers are encouraged to adopt alternative management practices on their farms to sequester SOC. On the basis of the availability of carbon (C) resources in the rural areas in China, the most promising practices are (1) incorporating more crop residue in the soils and (2) resuming traditional manure fertilizer. By implementing the alternative practices, increase in SOC content has been observed in some fields. This paper investigates how the C sequestration strategies could affect nitrous oxide (N2O) and methane (CH4) emissions from the agricultural soils in six selected sites across China. A process-based model, denitrification-decomposition or DNDC, which has been widely validated against data sets of SOC dynamics and N2O and CH4 fluxes observed in China, was adopted in the study to quantify the greenhouse gas impacts of enhanced crop residue incorporation and manure amendment under the diverse climate, soil, and crop rotation conditions across the six agroecosystems. Model results indicated that (1) when the alternative management practices were employed C sequestration rates increased, however, N2O or CH4 emissions were also increased for these practices; and (2) reducing the application rates of synthetic fertilizer in conjunction with the alternative practices could decrease N2O emissions while at the same time maintaining existing crop yields and C sequestration rates. The modeling approach could help with development of spatially differentiated best management practices at large regional scales

Computational design of steady 3D dissection puzzles

Dissection puzzles require assembling a common set of pieces into multiple distinct forms. Existing works focus on creating 2D dissection puzzles that form primitive or naturalistic shapes. Unlike 2D dissection puzzles that could be supported on a tabletop surface, 3D dissection puzzles are preferable to be steady by themselves for each assembly form. In this work, we aim at computationally designing steady 3D dissection puzzles. We address this challenging problem with three key contributions. First, we take two voxelized shapes as inputs and dissect them into a common set of puzzle pieces, during which we allow slightly modifying the input shapes, preferably on their internal volume, to preserve the external appearance. Second, we formulate a formal model of generalized interlocking for connecting pieces into a steady assembly using both their geometric arrangements and friction. Third, we modify the geometry of each dissected puzzle piece based on the formal model such that each assembly form is steady accordingly. We demonstrate the effectiveness of our approach on a wide variety of shapes, compare it with the state-of-the-art on 2D and 3D examples, and fabricate some of our designed puzzles to validate their steadiness

Late Neurosyphilis and Tertiary Syphilis in Guangdong Province, China: Results from a Cross-sectional Study.

Due to challenges in diagnosis and the need for complex laboratory tests, misdiagnosis of neurosyphilis and tertiary syphilis is common in China. We validated the diagnosis and examined the treatment of late neurosyphilis and tertiary syphilis in Guangdong Province, China. A cross-sectional study was conducted to collect data from late neurosyphilis and tertiary syphilis cases reported between 2009 and 2014 in Guangdong, China. Descriptive analysis, bivariate analyses and multiple logistic regressions were performed to determine the structural factors associated with correct diagnosis and standard treatment of late neurosyphilis and tertiary syphilis. Among the 3805 respondents (3805/3936, 96.7%), 1,837 (48.3%) met the misdiagnosed criteria. The misdiagnosis rate decreased over the study period (54.2% in 2009 and 41.8% in 2014). Only 27.1% and 24.9% of the correctly diagnosed late neurosyphilis and tertiary syphilis cases received standard treatment, respectively. Multiple logistic regression revealed that departments of dermatology or STDs [aOR = 3.24, 95% CI: 2.66-3.95], county or township level hospitals [aOR = 2.89, 95% CI: 2.14-3.89], and hospitals situated outside of Pearl River Delta area [aOR = 1.70, 95% CI: 1.46-1.97] had higher likelihood in misdiagnosis of neurosyphilis, compared to the reference groups. Targeted trainings for physicians and expanded syphilis screening services are urgently needed

Pay-it-forward gonorrhea and chlamydia testing among men who have sex with men in China:a study protocol for a three-arm cluster randomized controlled trial

BACKGROUND: Gonorrhea and chlamydia testing rates are poor among Chinese men who have sex with men (MSM). A quasi-experimental study suggested that a pay-it-forward strategy increased dual gonorrhea/chlamydia testing among MSM. Pay-it-forward offers an individual a gift (e.g., a free test) and then asks the same person if they would like to give a gift to another person. This article reports the protocol of a randomized controlled trial to evaluate dual gonorrhea/chlamydia test uptake and other outcomes among MSM in three arms - a pay-it-forward arm, a pay-what-you-want arm, and a standard of care arm. METHODS: Three hundred MSM will be recruited at three HIV testing sites in Guangzhou and Beijing. Testing sites include two hospital-based MSM sexually transmitted diseases clinics and one MSM community-based organization. Eligible participants will be born biologically male, aged 16 years or older, reporting previous anal sex with another man, having never participated in the pay-it-forward program, without previous gonorrhea and chlamydia testing in the past 12 months, and residing in China. Following a cluster randomized design, every cluster of ten participants will be randomly allocated into one of three arms: (1) a pay-it-forward arm in which men are offered free gonorrhea and chlamydia testing and then asked whether they would like to donate ("pay it forward") toward testing for future testers; (2) a pay-what-you-want arm in which men are offered free testing and told to decide how much to pay after receiving the test; (3) a standard of care arm in which men can pay the full price for dual gonorrhoea and chlamydia testing. The primary outcome is dual gonorrhoea/chlamydia testing as verified by administrative records. Secondary outcomes include incremental cost per test, incremental cost per diagnosis, community connectedness, and social cohesion. Primary outcome will be calculated for each arm using intention-to-treat and compared using one-sided 95% confidence intervals with a margin of 20% increase defined as superiority. DISCUSSION: This study will examine the pay-it-forward strategy in comparison to the standard of care in improving test uptake for gonorrhea and chlamydia. We will leverage the cluster randomized controlled trial to provide scientific evidence on the potential effect of pay-it-forward. Findings from this study will shed light on novel intervention methods for increasing preventive health service utilization and innovate ways to finance it among communities. TRIAL REGISTRATION: ClinicalTrials.gov, NCT03741725 . Registered on 12 November 2018

Blocking and being blocked on gay dating apps among MSM attending a sexual health clinic: an observational study

Background There are limited studies on blocking and men who have sex with men (MSM) health outcomes. We need such data in China, to better understand the relationship between Chinese MSM gay app use and health outcomes, thus providing insight on risky sexual behaviors and HIV transmission among Chinese MSM - one of the world's largest MSM communities. Blocking someone is when users select a function on an app to prevent another user from contacting them and being blocked is when someone is prevented from contacting another user. We studied the correlates of blocking on the world's largest gay dating app among Chinese MSM (N = 208). Methods We conducted a cross-sectional survey as part of an HIV testing intervention in Guangzhou, China, May-December 2019. Using logistic regression models, we estimated the correlates of blocking (e.g. sociodemographic characteristics, sexual behavior, HIV testing history, social network data). Results MSM had a mean age of 27.9 years (SD = 7.1) and median of one sexual partner in the last 3 months. About 62% had blocked someone in their lifetime and 46% had been blocked in their lifetime. Each additional male partner was associated with an 87% (aOR = 1.87, 95%CI = 1.03, 3.40) increased chance of being blocked. Reporting a versatile sexual role was related with a 90% (aOR = 0.10, 95%CI = 0.02, 0.45) decreased likelihood of blocking behavior and an 86% (aOR = 0.14, 95%CI = 0.04, 0.46) reduced chance of being blocked. Conclusions Number of male partners may be associated with blocking behavior, with implications for the design of online sexual health interventions

Pressured HIV testing "in the name of love": a mixed methods analysis of pressured HIV testing among men who have sex with men in China.

INTRODUCTION: HIV testing has rapidly expanded into diverse, decentralized settings. While increasing accessibility to HIV testing is beneficial, it may lead to unintended consequences such as being pressured to test. We examined the frequency, correlates and contexts of pressured HIV testing among Chinese men who have sex with men (MSM) using mixed methods. METHODS: We conducted an online survey of MSM (N = 1044) in May 2017. Pressured HIV testing was defined as being forced to test for HIV. We conducted logistic regression analysis to determine the associations between pressured HIV testing and socio-demographic and sexual behavioural factors. Follow-up interviews (n = 17) were conducted with men who reported pressured testing and we analysed qualitative data using a thematic analysis approach. RESULTS: Ninety-six men (9.2%) reported experiencing pressure to test for HIV. Regular male sex partners were the most common source of pressure (61%, 59/96), and the most common form of pressure was a threat to end a relationship with the one who was being pressured (39%, 37/96). We found a higher risk of pressured testing in men who had only used HIV self-testing compared to men who had never self-tested (AOR 2.39 (95%CI: 1.38 to 4.14)). However, this relationship was only significant among men with low education (AOR 5.88 (95% CI: 1.92 to 17.99)) and not among men with high education (AOR 1.62 (95% CI: 0.85 to 3.10)). After pressured testing, about half of men subsequently tested for HIV (55%, 53/96) without pressure - none reported being diagnosed with HIV. Consistent with this finding, qualitative data suggest that perceptions of pressure existed on a continuum and depended on the relationship status of the one who pressured them. Although being pressured to test was accompanied by negative feelings, men who were pressured into testing often changed their attitude towards HIV testing, testing behaviours, sexual behaviours and relationship with the one who pressured them to test. CONCLUSION: Pressured HIV testing was reported among Chinese MSM, especially from men with low education levels and men who received HIV self-testing. However, in some circumstances, pressure to test helped MSM in several ways, challenging our understanding of the role of agency in the setting of HIV testing

Pay-it-forward gonorrhoea and chlamydia testing among men who have sex with men in China:a randomised controlled trial

BACKGROUND: WHO recommends that men who have sex with men (MSM) receive gonorrhoea and chlamydia testing, but many evidence-based preventive services are unaffordable. The pay-it-forward strategy offers an individual a gift (eg, a test for sexually transmitted diseases) and then asks whether they would like to give a gift (eg, a future test) to another person. This study examined the effectiveness of a pay-it-forward programme to increase gonorrhoea and chlamydia testing among MSM in China. METHODS: We did a randomised controlled superiority trial at three HIV testing sites run by MSM community-based organisations in Guangzhou and Beijing, China. We included MSM aged 16 years or older who were seeking HIV testing and met indications for gonorrhoea and chlamydia testing. Restricted randomisation was done using computer-generated permuted blocks. 30 groups were randomised into three arms (1:1:1): a pay-it-forward arm in which men were offered free gonorrhoea and chlamydia testing and then asked whether they would like to donate for testing of prospective participants, a pay-what-you-want arm in which men were offered free testing and given the option to pay any desired amount for the test, and a standard-of-care arm in which testing was offered at ¥150 (US$22). There was no masking to arm assignment. The primary outcome was gonorrhoea and chlamydia test uptake ascertained by administrative records. We used generalised estimating equations to estimate intervention effects with one-sided 95% CIs and a prespecified superiority margin of 20%. The trial is registered with ClinicalTrials.gov, NCT03741725. FINDINGS: Between Dec 8, 2018, and Jan 19, 2019, 301 men were recruited and included in the analysis. 101 were randomly assigned to the pay-it-forward group, 100 to the pay-what-you-want group, and 100 to the standard-of-care group. Test uptake for gonorrhoea and chlamydia was 56% (57 of 101 participants) in the pay-it-forward arm, 46% (46 of 100 participants) in the pay-what-you-want arm, and 18% (18 of 100 participants) in the standard-of-care arm. The estimated difference in test uptake between the pay-it-forward and standard-of-care group was 38·4% (95% CI lower bound 28·4%). Among men in the pay-it-forward arm, 54 of 57 (95%) chose to donate to support testing for others. INTERPRETATION: The pay-it-forward strategy can increase gonorrhoea and chlamydia testing uptake among Chinese MSM and could be a useful tool for scaling up preventive services that carry a mandatory fee. FUNDING: US National Institute of Health; Special Programme for Research and Training in Tropical Diseases, sponsored by UNICEF, UNDP, World Bank, and WHO; the National Key Research and Development Program of China; Doris Duke Charitable Foundation; and Social Entrepreneurship to Spur Health