Evaluation of the optimal exposure settings for occlusal photography with digital cameras

Background and objectiveRecently, there have been produced several kinds of camera systems, lighting devices and image processing programs. The intraoral photographs are periodically required in pediatric dentistry, since the oral environment of children changes rapidly and dramatically because of disease, growth, and tooth eruption. However, the suitable settings for intraoral digital imaging have not yet been reported. In this study, single-lens reflex and mirrorless cameras were used with a ring flash, ring light emitting diode (LED), or standard fluorescent lamp to determine the optimal exposure parameters for occlusal photography.Materials and methodsFifty-six dentists evaluated images of a discolored nonvital central incisor and first molar with recurrent caries and stained fissures clipped from a low-magnification photograph of the adult maxillary occlusal surface reflected in a mirror by using various F-numbers (representing aperture), shutter speeds, and International Organization for Standardization (ISO) numbers (representing light sensitivity).ResultsThe results showed that F-numbers between 5.6 and 10, shutter speeds faster than 1/30s, and ISO 800 produce the best occlusal images when a 60 mm f/2.8 Macro lens is used. Better images are obtained with ring LED than with ring flash. Furthermore, ISO 3200 is required for low-magnification photography in natural light. Finally, intraoral digital images should be captured under low magnification, because tilted or deflected images can be adjusted by using imaging software.     

Friendship 2.0: Adolescents' experiences of belonging and self-disclosure online

This study explores the role that digital media technologies play in adolescents' experiences of friendship and identity. The author draws on findings from in-depth interviews with 32 adolescents (15 girls, 17 boys) ages 13–18 (M = 15.5 years) attending one of seven secondary schools in Bermuda. The adolescents were asked to describe the nature of their online exchanges with friends and the value they ascribe to these conversations. A thematic analysis of their responses revealed that online peer communications promote adolescents' sense of belonging and self-disclosure, two important peer processes that support identity development during adolescence. At the same time, the unique features of computer-mediated communication shape adolescents' experiences of these processes in distinct ways. Gender and age differences show that adolescents' online peer communications are not uniform; the characteristics that distinguish adolescents offline also shape their online activities.     

中国学术期刊网络首发论文撤回状况的调查分析——以中国知网2017—2019年数据为例

【目的】 了解我国学术期刊网络首发论文出版后的撤稿及更正状况,以及问题论文撤回过程中《中国知网网络出版文献出版状态变更与内容更正规范》(以下简称《规范》)的执行情况。 【方法】 首先,检索CNKI平台2017—2019年带有“撤回”标记的网络首发论文的撤回声明;其次,下载撤回声明并编码保存,将撤回论文的目录导出至参考文献管理软件Endnote X9进行相关统计,将撤稿声明的文本导入到质性研究数据分析软件NVivo 12 Plus进行原因分类;最后,对网络首发撤稿论文的学科分布、来源期刊、撤回原因等进行分析。 【结果】 2017—2019年CNKI共撤回网络首发论文389篇,其中“撤回”论文310篇,“撤稿”论文74篇,“勘误”论文5篇;有明确撤回原因的论文有278篇,占比为71.47%,111篇没有说明撤回原因,占比为28.53%;因学术不端、署名问题、出版管理、质量控制、其他等原因撤回的论文分别为32、25、82、118、21篇。 【结论】 网络首发论文撤回率偏高(389/182654,0.21%),《规范》执行率偏低(6/389,1.54%);撤稿原因不明确、不具体,且存在故意遮掩学术不端事实的现象。学术期刊编辑出版单位和数字化出版平台应进一步规范网络首发论文的流程管理和内容审核,增强撤回原因的透明性、撤回声明的易见性和撤回过程的可回溯性。     

Social media use and influenza vaccine uptake among White and African American adults

Influenza vaccination rates in the U.S. remain low at 41% among adults over 18 years according to the Centers for Disease Control and Prevention’s 2016 data. Reasons for the low rate vary and include factors such as risk perception, vaccine hesitancy, and access to health care. This cross-sectional study sought to examine the relationship between social media use and influenza vaccine uptake among a sample of White and African Americans over 18 years of age. Using bivariate, and unadjusted and adjusted logistic regression tests, this study examined the relationship among social media use, social media as a source of health information, and influenza vaccination status in 2015. Our results indicate that users of Twitter (OR4.41, 95%CI: 1.43–13.60) and Facebook (OR 1.66, 95%CI: 1.01–2.72) as sources of health information were more likely to be vaccinated in comparison to users who do not use Twitter or Facebook as a source of health information. These findings have implications for the potential of using social media platforms to disseminate influenza vaccine information and encourage users to get vaccinated annually.     

A novel audio forensic data-set for digital multimedia forensics

Today, digital multimedia (audio, video, images) is a common evidential source in litigation and criminal justice proceedings, and, not surprisingly, multimedia forensics is an active research area. One particular challenge faced by multimedia forensic researchers is the lack of a comprehensive and publicly available data-set for evaluating existing and new algorithms. This paper presents a digital audio forensic data-set, designed to facilitate evaluation of audio forensic algorithms (e.g. microphone identification, acoustic environment identification and splice detection). This paper also briefly describes the data-collection settings, microphones, speakers, languages and notations used. Existing tamper-detection techniques rely on artefacts due to recording devices, codec and/or the acoustic environment in the audio in question. Experimental results show that the selected approaches achieved promising results.     

DSA引导下血管腔内成形术治疗下肢动脉硬化闭塞症的临床研究

目的:探讨DSA引导下血管腔内成形术(TA)治疗下肢动脉硬化闭塞症(ASO-LE)的临床效果。方法:2017年3月至2019年4月,手术治疗的ASO-LE患者93例,依据治疗方式的不同分为A组(行TA,n=49)和B组[行下肢动脉旁路移植术(LEABG),n=44],两组患者均在数字减影血管造影(DSA)引导下进行。对比两组患者手术成功率;两组患者术前即刻(T1)、术后1 d(T2)、术后3 d(T3)及术后1周(T4)时刻视觉模拟疼痛评分(VAS);对比术前(T1')、术后1个月(T2')及术后3个月(T3')时刻两组患者下肢缺血程度[患者踝肱指数(ABI)、趾肱指数(TBI)];对比T1'、T2'及T3'时刻两组患者足背动脉血流动力学[足背动脉内径(D)、血流峰速(PV)、血流量(BF)];对比T1'、T2'及T3'时刻两组患者下肢感觉神经传导速度(SNCV)和运动神经传导速度(MNCV);术后6个月,对比两组患者并发症发生率。结果:两组患者手术成功率无显著差异(P>0.05);患者VAS评分组间、时间、交互对比差异均有统计学意义(P<0.05),与T1相比,T2、T3及T4时两组患者VAS评分均降低(P<0.05),与T2相比较,T3及T4时两组患者VAS评分均降低(P<0.05),与T3相比较,T4时两组患者VAS评分均降低(P<0.05),A组T2、T3及T4时刻VAS评分均低于B组(P<0.05);ABI、TBI、D、PV、BF、SNCV和MNCV组间、时间、交互对比差异均有统计学意义(P<0.05);与T1'相比,T2'及T3'时两组患者ABI、TBI、D、PV、BF、SNCV和MNCV均升高(P<0.05);与T2'相比较,T3'时2组患者ABI、TBI、下肢SNCV和MNCV均升高(P<0.05),A组T2'及T3'时刻ABI、TBI、D、PV、BF、SNCV和MNCV均高于B组(P<0.05);A组患者并发症发生率显著低于B组(P<0.05)。结论:相比LEABG,DSA引导下对ASO-LE患者进行TA治疗能够减轻疼痛,改善下肢缺血及足背动脉血流动力学,提高下肢SNCV和MNCV,降低并发症的发生率。     

失衡与治理:学术期刊数字出版产业链利益分配问题研究

【目的】 探讨学术期刊数字出版产业链中的市场主体利益分配失衡问题的解决方案,以满足各方的合理利益诉求。【方法】 运用文献法、个案研究法等,对我国学术期刊数字出版产业链上、中、下游市场主体之间利益分配失衡的现状及原因进行分析。【结果】 数据库平台企业的双边市场地位与商业模式、学术期刊数字出版产品特性与收费模式、主管部门监管不到位、行政力量推动下的非完全市场化运行机制、版权维护动力不足,以及尊重知识产权意愿不强是当前学术期刊数字出版产业链利益分配失衡的主要原因。【结论】 充分发挥主管单位与行业协会监管职能、对数据库平台企业进行改革、引入区块链技术、构建基于版权保护的利益分配机制等是平衡各方利益的有效对策。