Decoupled Contrastive Learning

Contrastive learning (CL) is one of the most successful paradigms for self-supervised learning (SSL). In a principled way, it considers two augmented "views" of the same image as positive to be pulled closer, and all other images as negative to be pushed further apart. However, behind the impressive success of CL-based techniques, their formulation often relies on heavy-computation settings, including large sample batches, extensive training epochs, etc. We are thus motivated to tackle these issues and establish a simple, efficient, yet competitive baseline of contrastive learning. Specifically, we identify, from theoretical and empirical studies, a noticeable negative-positive-coupling (NPC) effect in the widely used InfoNCE loss, leading to unsuitable learning efficiency concerning the batch size. By removing the NPC effect, we propose decoupled contrastive learning (DCL) loss, which removes the positive term from the denominator and significantly improves the learning efficiency. DCL achieves competitive performance with less sensitivity to sub-optimal hyperparameters, requiring neither large batches in SimCLR, momentum encoding in MoCo, or large epochs. We demonstrate with various benchmarks while manifesting robustness as much less sensitive to suboptimal hyperparameters. Notably, SimCLR with DCL achieves 68.2% ImageNet-1K top-1 accuracy using batch size 256 within 200 epochs pre-training, outperforming its SimCLR baseline by 6.4%. Further, DCL can be combined with the SOTA contrastive learning method, NNCLR, to achieve 72.3% ImageNet-1K top-1 accuracy with 512 batch size in 400 epochs, which represents a new SOTA in contrastive learning. We believe DCL provides a valuable baseline for future contrastive SSL studies.Comment: Accepted by ECCV202

Identifying Areas with Disproportionate Local Health Department Services Relative to Opioid Overdose, HIV and Hepatitis C Diagnosis Rates: A Study of Rural Illinois

Background: U.S. rural populations have been disproportionately affected by the syndemic of opioid-use disorder (OUD) and the associated increase in overdoses and risk of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) transmission. Local health departments (LHDs) can play a critical role in the response to this syndemic. We utilized two geospatial approaches to identify areas of discordance between LHD service availability and disease burden to inform service prioritization in rural settings.Methods: We surveyed rural Illinois LHDs to assess their OUD-related services, and calculated county-level opioid overdose, HIV, and hepatitis C diagnosis rates. Bivariate choropleth maps were created to display LHD service provision relative to disease burden in rural Illinois counties. Results: Most rural LHDs provided limited OUD-related services, although many LHDs provided HIV and HCV testing. Bivariate mapping showed rural counties with limited OUD treatment and HIV services and with corresponding higher outcome/disease rates to be dispersed throughout Illinois. Additionally, rural counties with limited LHD-offered hepatitis C services and high hepatitis C diagnosis rates were geographically concentrated in southern Illinois. Conclusions: Bivariate mapping can enable geographic targeting of resources to address the opioid crisis and related infectious disease by identifying areas with low LHD services relative to high disease burden

HIV Prevention and Care Among Black Cisgender Sexual Minority Men and Transgender Women: Protocol for an HIV Status–Neutral Cohort Study Using an Observational-Implementation Hybrid Approach

Background: Black cisgender gay, bisexual, and other sexual minority men (SMM) and transgender women (TW) continue to be heavily affected by HIV. Further research is needed to better understand HIV prevention and care outcomes in this population. In particular, there is a need for research examining the impact of substance use and sleep health on HIV prevention and treatment outcomes among Black SMM and TW. Objective: This paper outlines the study methods being used in the recently launched follow-up study to the Neighborhoods and Networks (N2) study, which we refer to as N2 Part 2 (N2P2). N2P2 aims to address this gap in the literature, build off the findings of the original N2 study, and identify socioenvironmental determinants of health, including whether neighborhood and network factors mediate and moderate these relationships. Methods: Building on the N2 cohort study in Chicago from 2018 to 2022, N2P2 used a prospective longitudinal cohort design and an observational-implementation hybrid approach. With sustained high levels of community engagement, we aim to recruit a new sample of 600 Black SMM and TW participants residing in the Chicago metropolitan statistical area. Participants are asked to participate in 3 study visits across an 18-month study period (1 visit every 9 months). Four different forms of data are collected per wave: (1) an in-person survey, (2) biological specimen collection, (3) a daily remote ecological momentary assessment for 14 days after each study visit, and (4) data from electronic health records. These forms of data collection continue to assess neighborhood and network factors and specifically explore substance use, sleep, immune function, obesity, and the implementation of potential interventions that address relevant constructs (eg, alcohol use and pre-exposure prophylaxis adherence). Results: The N2P2 study was funded in August 2021 by the National Institute of Drug Abuse (R01DA054553 and R21DA053156) and National Heart, Lung, and Blood Institute (R01HL160325). This study was launched in November 2022. Recruitment and enrollment for the first wave of data collection are currently ongoing. Conclusions: The N2P2 study is applying innovative methods to comprehensively explore the impacts of substance use and sleep health on HIV-related outcomes among an HIV status-neutral cohort of Black SMM and TW in Chicago. This study is applying an observational-implementation hybrid design to help us achieve findings that support rapid translation, a critical priority among populations such as Black SMM and TW that experience long-standing inequities with regard to HIV and other health-related outcomes. N2P2 will directly build off the findings that have resulted from the original N2 study among Black SMM and TW in Chicago. These findings provide a better understanding of multilevel (eg, individual, network, and neighborhood) factors that contribute to HIV-related outcomes and viral suppression among Black SMM and TW. International registered report identifier (irrid): DERR1-10.2196/48548.</p

Comparative epidemiology of betel nut use versus ecstasy use among Taiwanese adolescents: Findings from a national survey

目的：探討與青少年使用檳榔及搖頭丸相關之社會人口特徵、使用其他精神作用性物質、行為問題是否有差異性存在。 方法：將2004年至2006年以多階段隨機群集抽樣收集的全國青少年在校樣本，依照使用檳榔及搖頭丸之經驗，區分成四組使用者：無檳榔及搖頭丸使用經驗者 (51,009人)、只使用檳榔者 (1965人)、只使用搖頭丸者 (196人)、使用過檳榔及搖頭丸者(152人)。利用自我陳報問卷來蒐集青少年的社會人口特徵、其他精神成癮性物質使用經驗，並且使用中文版青少年自陳量表 (Youth Self Report)來測量行為問題。 結果：工作經驗、較多零用錢、翹課經驗、性行為經驗、外化行為問題為檳榔及搖頭丸使用的相關因子。與使用搖頭丸者相比，檳榔使用者較傾向為男性、居住於臺灣東部地區、受家人或朋友的影響而開始使用、有較高焦慮、憂鬱、思考問題、注意力問題。相較而言，搖頭丸使用者較傾向為女性、使用其他精神作用性物質、因娛樂助興而開始使用、在娛樂場所使用居多。 結論：青少年檳榔使用者與搖頭丸使用者在社會人口特徵、使用其他精神作用性物質、行為問題上有異質性存在。對此異質性的了解，可以幫助青少年特定物質使用之防制工作。Aims: To investigate whether variation may exist in betel nut- and ecstasy-involved adolescents in terms of sociobehavioral characteristics, the experience of psychoactive substance use, and behavioral/emotional problems. Methods: Students (n = 53,528) aged 12 to 18 sampled via stratified, multistage, random cluster sampling in 2004, 2005, and 2006 throughout Taiwan were categorized into four groups: betel nut- and ecstasy-naive (n = 51,009), betel nut use only (n = 1965), ecstasy use only (n = 196), and use of both (n = 152). Participants completed a questionnaire with information on sociodemographic features, substance-use experiences, and the Chinese adaptation of the Youth Self Report. Results: Having a job, a larger weekly allowance, truancy, sexual experience, and externalizing behaviors were all in strong association with the involvement of either betel nut or ecstasy use. Compared with ecstasy-only users, betel nut-only users were more likely to be male, from the Eastern region of Taiwan, with initiation motivated by family members or friends, and having excess risks for Anxiety/Depression, Thought Problems, and Attention Problems. In contrast, ecstasy-only users were more likely to be female and involved in using other illegal drugs, with their initiation motivated by entertainment and with the drug-use taking place in such settings. Conclusions: The variation in the experience of psychoactive substance-use and behavioral problems for betel nut and ecstasy users suggests the existence of subgroups of drug-using adolescents in Taiwan. The identification of such heterogeneity may guide the efforts to reduce substance use and develop subgroup-tailored preventive programs

Comparative Epidemiology of Betel Nut Use Versus Ecstasy Use among Taiwanese Adolescents: Findings from a National Survey

Aims: To investigate whether variation may exist in betel nut- and ecstasy-involved adolescents in terms of sociobehavioral characteristics, the experience of psychoactive substance use, and behavioral/emotional problems. Methods: Students (n = 53,528) aged 12-18 sampled via stratified , multistage, random cluster sampling in 2004, 2005, and 2006 throughout Taiwan were categorized into four groups: betel nut- and ecstasy-naive (n = 51,009), betel nut use only (n = 1965), ecstasy use only (n = 196), and use of both (n = 152). Participants completed a questionnaire with information on sociodemographic features, substance-use experiences, and the Chinese adaptation of the Youth Self Report. Results: Having a job, a larger weekly allowance, truancy, sexual experience, and externalizing behaviors were all in strong association with the involvement of either betel nut or ecstasy use. Compared with ecstasy-only users, betel nut-only users were more likely to be male, from the Eastern region of Taiwan, with initiation motivated by family members or friends, and having excess risks for Anxiety/Depression, Thought Problems, and Attention Problems . In contrast, ecstasy-only users were more likely to be female and involved in using other illegal drugs, with their initiation motivated by entertainment and with the drug use taking place in such settings. Conclusions: The variation in the experience of psychoactive substance use and behavioral problems for betel nut and ecstasy users suggests the existence of subgroups of drug-using adolescents in Taiwan. The identification of such heterogeneity may guide the efforts to reduce substance use and develop subgroup- tailored preventive programs

Reliability of Ultrasonography in Evaluating Hyoid Bone Movement

Background: Timely and adequate laryngeal elevation along with hyoid bone movement is an essential component of the swallowing movement under normal physiological conditions. The purpose of this study was to verify the reproducibility of using ultrasonography to evaluate hyoid bone displacement during swallowing through the assessment of inter- and intrarater reliability and examine its accuracy by comparing the results with videofluoroscopic swallowing study (VFSS). Methods: A self-designed water balloon was fixed to the transducer, which provided good contact between the transducer and the submental skin. Ten participants with dysphagia were recruited. The measurements of hyoid bone displacement using ultrasonography were performed by two of the authors. All the participants underwent ultrasonographic examinations and VFSS within 24 hours. Results: The intrarater intraclass correlation coefficient (ICC) of the two examiners was 0.996 and 0.959, respectively (p<0.01); the interrater ICC between the two examiners was 0.892 (p<0.05). ICCs between VFSS and ultrasonography for two researchers were 0.815 and 0.916 (p<0.01). Conclusion: Submental ultrasonography is a reliable and accurate method for assessing the hyoid bone movement

Is artificial dermis an effective tool in the treatment of tendon-exposed wounds?

As flap surgery remains the main technique to close wounds with tendon exposure, the application of artificial dermis in these complex soft tissue wounds is seldom reported. The purpose of this article is to review our experiences in the treatment of tendon-exposed wounds with artificial dermis. This retrospective study included 23 patients with 33 tendon-exposed wounds treated with artificial dermis from 2004 to 2009. Data including patient demographics, wound type, duration from artificial dermis implantation to split thickness skin grafting, surgical complications, and clinical outcome were obtained by chart review. Successful treatment was defined as the formation of golden-yellow neodermis followed by successful split thickness skin grafting. Among the 33 tendon-exposed wounds, 11 were secondary to chronic ulcers, 16 to acute wounds, and 6 to surgical wounds after hypertrophic scar excision. The mean patient age was 49 years. The overall success rate with the artificial dermis technique was 82%, including 63% in the chronic ulcer group, 88% in the acute wounds, and 100% in the surgical wounds. In the success group, 11% of the wounds required repeated artificial dermis implantations. Within the failure group, two wounds were closed by below knee amputation, two by local flap surgery, and two were allowed spontaneous healing as a result of graft failure. We have demonstrated an overall success rate of 82% for tendon-exposed wound closure by using artificial dermis. The outcome was better in surgical and acute wounds than in chronic wounds

Geographic Density and Uptake of Pre-exposure Prophylaxis (PrEP) Among Young Gay, Bisexual and Other Sexual Minority Men: A Global Positioning System (GPS) Study

International audienceThe geographic availability of pre-exposure prophylaxis (PrEP) providers is one important factor that significantly affects PrEP uptake. While most previous studies have employed spatial accessibility in static residential neighborhood definitions or self-reported healthcare accessibility, we examined the associations of the objectively measured geographic density of PrEP services with current PrEP use, using global positioning system (GPS) among sexual minority men (SMM) in New York City. 250 HIV-negative SMM participated in a 2-week GPS monitoring (January 2017-January 2018). Geographic PrEP density was measured as total numbers of PrEP providers in (1) individual activity space defined as daily path area of GPS points, (2) residential street network buffers and (3) census tract and ZIP code of residential locations. Geographic PrEP density within GPS-based activity space was positively associated with current PrEP use (prevalence ratio for 50-m activity space = 1.10, 95% confidence interval: [1.02, 1.18]). PrEP provider counts in residential buffer areas and administrative neighborhoods were not associated with PrEP use. Although it is not generalizable beyond New York City, our finding suggests the importance of daily mobility pattern in HIV prevention and PrEP implementation strategies