Incidence and risk factors associated with injuries during static line parachute training in Royal Thai Army

Background:Incidence and risk factors of parachute injuries has been studied in developed countries,but not in trainees of the airborne forces in the Royal Thailand Army.Methods:A prospective cohort study was conducted among 992 military personnel who attended the basic airborne training program from February to July 2018.Information sheets were used to collect data about(a)personal demographics;(b)environmental conditions surrounding the parachute practice;and(c)parachute-related injuries.The incidence rate of injury was then calculated.Risk factors were examined using multilevel Poisson regression analysis and presented as incidence rate ratio(IRR)and 95%confidence interval(95%CI).Results:A total of 166 parachute-related injuries occurred in 4677 jumps.The incidence rate of injury was 35.50 per 1000 jumps(95%CI 30.04–41.21).Factors significantly related to parachute injury included:jumping with equipment versus without equipment[adjusted IRR(95%CI):1.28(0.88–1.87)],higher wind speed[1.54(1.27–1.87)per knot],airplane versus helicopter exit[1.75(0.68–4.55)],side versus rear exit[2.13(1.43–3.23)],night versus day jumping[2.19(0.81–5.90)],and presence of motion sickness[3.43(1.93–6.92)].Conclusions:To prevent military static line parachute injuries,the following factors should be taken into consideration:type of aircraft,aircraft exit,time of the day,equipment,motion sickness and wind speed.Trial registration:The project was certified by the Research Ethics Committee,Faculty of Medicine,Chulalongkorn University(IRB No.697/60).

Adapting the botanical landscape of Melbourne Gardens(Royal Botanic Gardens Victoria)in response to climate change

Botanic gardens around the world maintain collections of living plants for science, conservation, education, beauty and more. These collections change over time-in scope and content-but the predicted impacts of climate change will require a more strategic approach to the succession of plant species and their landscapes. Royal Botanic Gardens Victoria has recently published a 'Landscape Succession Strategy'for its Melbourne Gardens, a spectacular botanical landscape established in 1846. The strategy recognizes that with 1.6 million visitors each year, responsibility for a heritage-listed landscape and the need to care for a collection of 8500 plant species of conservation and scientific importance, planting and planning must take into account anticipated changes to rainfall and temperature. The trees we plant today must be suitable for the climate of the twenty-second century. Specifically, the Strategy sets out the steps needed over the next twenty years to transition the botanic garden to one resilient to the climate modelled for2090. The document includes a range of practical measures and achievable(and at times somewhat aspirational) targets. Climate analogues will be used to identify places in Australia and elsewhere with conditions today similar to those predicted for Melbourne in 2090, to help select new species for the collection. Modelling of the natural and cultivated distribution of species will be used to help select suitable growth forms to replace existing species of high value or interest. Improved understanding of temperature gradients within the botanic garden, water holding capacity of soils and plant water use behaviour is already resulting in better targeted planting and irrigation. The goal is to retain a similar diversity of species but transition the collection so that by 2036 at least 75% of the species are suitable for the climate in 2090. Over the next few years we hope to provide 100% of irrigation water from sustainable water sources, and infrastructure will be improved to adapt to predicted higher temperatures and more climatic extremes. At all times there will be a strong focus on assisting the broader community in their response to climate change.

Cyclone and Tsunami Hazards in the Arabian Sea-A Numerical Modelling Case Study by Royal HaskoningDHV

Significant loss of life and damage to properties, ecosystems and marine facilities occur due to various natural hazards such as cyclones and tsunamis. Royal HaskoningDHV has developed regional hydrodynamic and wave models covering the Northern Arabian Sea to address these issues. Cyclone modelling was carried out on 11 major cyclones since 1945 and the tsunami modelling on an earthquake along the Makran Fault Line in 1945. Sample results from these modelling studies are presented in this paper. The methodology described in this article for modelling cyclones and tsunamis in the Arabian Sea could be applied to simulate these natural hazards at other sites around the world.

Experience with Thoracic Aortic Stent-Grafting at the Royal Brisbane and Women’s Hospital: Outcomes from the First Decade

Objectives: To describe thoracic endovascular aortic repair (TEVAR) outcomes at the Royal Brisbane and Women’s Hospital between 2001-2010. Design: Prospective cohort study. Results: We successfully treated 95 of 97 patients for a 98% procedural success rate. Of the treated patients, 68 (72%) were males and mean age was 61 ± 17 years. Average follow up was 3.6 ± 2.0 years. Pathologies treated were: dissection (n = 35), aneurysmal disease (n = 32), traumatic disease (n = 19), coarctation (n = 5) and miscellaneous (n = 4). There was one peri-procedural myocardial infarction. Renal complications occurred in 7 patients (3 with doubling creatinine and 4 requiring temporary renal replacement therapy). Stroke occurred in 2 patients and paresis in 2 patients (permanent in one). Six patients died during index hospitalization and 17 deaths occurred during follow-up, 2 of which were confirmed secondary to aortic pathology. Age (HR 1.08 per year, p < 0.01) and ASA class (HR 2.2 per class, p = 0.02) were independently associated with mortality. There were 25 re-interventions in 22 patients. Eighteen of these re-interventions in 16 patients were related to the management of complications of TEVAR of which 13 were for endoleaks;eight type I, four type II, one type III. Conclusion: TEVAR can be used to treat thoracic aortic pathology but questions remain regarding long-term durability.

沙门菌血清分型方法的比较

血清分型是沙门菌最基本和最重要的流行病学调查手段,不同血清型沙门菌引起的临床症状和造成的危害不同,快速准确地进行血清分型对于畜禽沙门菌病的防控和公共卫生安全意义重大。基于此,本试验选择我国1971—2020年分离的51株沙门菌(13种血清型),分别用全基因组测序(WGS)分型方法和液相芯片分型方法进行血清分型,并与玻片凝集法进行比较,分析3种分型方法的优劣。结果显示,玻片凝集法测得51株沙门菌的血清分型结果与原始结果一致;WGS分型方法和液相芯片分型方法分别测得34株和23株沙门菌血清分型与玻片凝集法结果一致。3种分型方法相比,WGS分型方法可鉴定出玻片凝集法和液相芯片分型方法无法分型的菌株,在操作时间和成本上更具优势。本试验可为沙门菌的血清分型研究提供参考。

新一代通用视频编码标准H.266/VVC:现状与发展

相比于上一代标准,新一代通用视频编码标准(H.266/VVC)在同等质量下能够节省大约50%的码率,且适用于多种多样的视频应用场景。论文从H.266/VVC的关键技术出发,对标准的现状、实现和应用发展进行深入探讨。H.266/VVC沿用既往标准中的双层码流体系和混合编码框架,针对帧内预测、帧间预测、变换、量化、环路滤波等所有主要编码模块进行了技术革新,并为屏幕内容视频等应用提供了高效的专用编码工具。H.266/VVC标准目前已处于实用化阶段,官方参考软件VTM和开源编解码器VVenC/VVdeC是目前最具代表性的软件编解码实现。对H.266/VVC的性能分析可以看出:H.266/VVC针对高分辨率视频取得的编码增益更为突出;主要编码工具对性能的贡献通常以复杂度为代价,但也有部分编码工具在提升编码性能的同时可降低整体编码复杂度。H.266/VVC的硬件实现面临诸多挑战,发展明显滞后于软件实现,现有研究主要集中在对具体编码模块的硬件加速方面。H.266/VVC标准发布之后,下一代视频编码标准的发展目前仍围绕混合编码框架进行探索,聚焦在两大方向:超越VVC的增强压缩关注更为先进的、非神经网络的编码工具,基于神经网络的视频编码则探索采用神经网络的编码工具。除此之外,部分或完全跳出现有混合编码框架的端到端视频编码也在飞速发展,未来视频编码标准与神经网络结合成为趋势,但面临着计算资源依赖和稳定结构两方面的考验。

含水率对红层泥岩填料刚度劣化特性及微观结构影响研究

为研究含水率对红层泥岩填料刚度劣化规律和微观结构的影响,开展了不同含水率下三轴不排水剪切试验、压汞试验和扫描电镜试验,基于能量守恒定律推导了填料刚度劣化与弹塑性应变能增量间的关系。结果表明:填料黏聚力随含水率增加而降低,内摩擦角则随含水率增加先增加后降低。填料结构损伤由应变能转化引起,从宏观上表现为刚度劣化。归一化刚度比值随塑性应变能增量占比增加而线性降低,随应力发展呈非线性衰减。以最优含水率为界,当试样在干侧时,填料有较好的荷载抵抗能力;湿侧填料荷载抵抗能力远低于干侧。损伤应力等值线与等含水率线构成上下界为对数曲线的状态面。填料孔隙分布在干侧为单峰形态,粒间接触较为紧密,结构稳定性好。在湿侧呈双峰结构,团聚体排列定向性程度较低。填料应在干侧压实填筑,推荐采用5%~7%作为填筑目标含水率。

食品工程研究生导师团队培养模式研究

国内外发展趋势表明,构建研究生导师团队培养模式将成为高校研究生培养的主流。本文以昆明理工大学食品科学与工程学院食品功能因子研究与利用团队为例,阐述了传统单一导师培养模式存在的弊端,提出了研究生导师团队建设以及研究生培养的具体实践方案,以期为食品工程硕士研究生的培养提供借鉴。

甲醇与汽油进气道喷雾撞壁特性对比

为了探究甲醇发动机冷启动困难的本质,基于外轮廓修正策略构建了透明气道模型,并采用光学畸变矫正技术,可视化对比研究了进气温度、进气流量和喷射压力对进气道甲醇和汽油喷雾特性的影响.结果表明:进气温度的升高增加了甲醇和汽油喷雾面积,并且对汽油促进效果更好,在一定程度上减少了喷雾湿壁长度.进气流动促进了甲醇和汽油喷雾的发展,并使甲醇喷雾面积大于汽油,但高进气流量下喷雾湿壁严重,合适的进气流量为15~30 m^(3)/h.提高喷射压力,增加了喷雾贯穿距和喷雾面积,但是喷雾湿壁长度也随之增加,合适的进气道相对喷射压力为0.2 MPa.

点渲染方式对量化点云主观质量的影响及算法优化

为探究点渲染方式对量化点云主观质量的影响并优化渲染算法,设计了不同基础几何体类型和渲染半径计算方式的点云主观质量评价实验。通过威尔科克森符号秩检验和双独立样本T检验,分析了基础几何体类型和最近邻渲染算法对几何和属性量化失真点云主观质量的影响。实验结果表明:基础几何体类型由于混叠程度不同而对主观质量影响不同,基础几何体混叠面积越大则主观质量越低;最近邻渲染算法对主观质量影响不显著,该算法减少了点云渲染后空洞的产生,却增大了混叠程度。在属性失真较小时,最近邻渲染算法效果优于渲染半径固定算法;在属性失真较大时,则劣于渲染半径固定的算法。结合主观实验结果,建立了混叠、空洞失真和基础几何体渲染半径的数学模型,在几何量化采用八叉树剪枝的基础上,通过空间相似性对模型参数进行简化并求解,提出一种利用几何量化参数计算基础几何体渲染半径的算法。与最近邻渲染算法相比,所提算法节省了52%的时间复杂度,渲染点云峰值信噪比提升了12.3%,主观质量分数提升了0.5。研究减少了计算资源,提高了渲染效率,可为渲染器的设计和优化提供参考。

基于脱脂芝麻渣酶解液美拉德反应制备浓香型调和芝麻油的研究

脱脂芝麻渣经碱性蛋白酶处理获得酶解液,将其与芝麻油混合进行美拉德生香源反应,制备浓香型芝麻油风味产物,之后与自制芝麻油调配制备浓香型调和芝麻油。以感官评分为指标,研究了酶解时间、美拉德反应温度、美拉德反应时间、料油比和调配比5个因素。确定最佳工艺条件为脱脂芝麻渣酶解时间3 h,美拉德反应温度120℃,美拉德反应时间40 min,料油比10∶1,调配比1∶12,制得的浓香型调和芝麻油的风味最佳。

“语义通信的数学理论”序言

客观世界由物质、能量和信息组成。探索和利用信息是信息时代的主要驱动力。回顾信息与通信的历史,如180年的经典通信和半个世纪的移动通信,我们看到了诸多通信技术的杰出成就,如超高速光通信、卫星通信、互联网、3G/4G/5G移动通信等。

基于离散裂隙网络的围岩注浆加固规律研究

基于输水隧洞裂隙围岩特征建立了二维离散裂隙网络模型,将宾汉姆流体在单一饱和裂隙中的两相流本构扩展到裂隙网络,模拟浆液在裂隙岩体中的流动扩散过程,得到不同注浆时间下注浆圈的形成范围;将注浆圈导入三维裂隙网络模型,基于水力耦合计算研究了在衬砌和注浆加固下,隧洞围岩的应力、变形与水压分布特性。结果表明:围岩注浆圈几何形态受裂隙分布特征的影响,呈各向异性分布;衬砌可有效控制围岩变形,相比无衬砌的工况隧道最大位移量减少了约50%,而注浆圈的形成可有效降低作用在衬砌上的围岩应力,缓解由外水压力引起的应力集中。本文成果可为富水岩体中隧道和地下洞室等深地工程的加固设计提供技术支撑。

基于深度强化学习的机器人轴孔装配策略仿真研究

针对现有轴孔装配方法存在的依赖于精确的接触状态模型、数据采集困难、采样效率低、安全性差等问题,提出了一种基于DRL的机器人轴孔装配策略仿真研究方法。搭建了基于ROSGazebo机器人轴孔装配仿真环境,提出了基于最小二乘法对力/力矩传感器进行重力补偿的方法;基于RL的范式对轴孔装配问题建模,并提出了一种基于SAC(soft actor-critic)算法的机器人轴孔装配方法;通过ROS建立了仿真环境与深度强化学习算法的通信机制。实验结果表明:该算法能够使机器人自主且柔顺地完成轴孔装配任务,并具有较好的泛化性。

考虑频率空间分布特性的虚拟惯量配置优化

高比例电力电子设备并网改变了电力系统频率响应特性,使各节点的频率动态异质化明显,导致低系统惯量、弱频率稳定等问题。电力电子装备提供虚拟惯量支撑是提升频率稳定性的有效途径之一。为改善以新能源为主体的新型电力系统频率响应性能,提出一种考虑新型电力系统频率响应空间分布差异化的虚拟惯量配置优化方法。首先,基于分频器理论,构建反映频率空间分布差异特性的系统频率响应模型。其次,为定量描述惯量分布对节点频率响应性能的影响,提出节点惯量指标与节点动能偏差指标。然后,考虑频率空间分布特性,以优化扰动后各节点的能量不平衡为目标,建立虚拟惯量配置优化模型。最后,通过仿真验证了节点惯量指标有效性以及所提虚拟惯量配置方法对系统节点频率稳定性的提升作用。

Loculated pericardial hematoma diagnosed with point-of-care ultrasound

Pericardial hematoma is a rare but potentially lifethreatening consequence following cardiac surgery that requires prompt recognition and intervention.Patients can present with symptoms such as chest pain,dyspnea,tachycardia,and hypotension,which may mimic other post-operative issues.Loculated pericardial hematoma compressing the atria might be difficult to diagnose.Bleeding and hematoma are more common in patients receiving early anticoagulant therapy.A focused cardiac ultrasound (Fo CUS) plays a pivotal role in the diagnosis,revealing the presence of pericardial effusion and signs of cardiac compression.The aim of this report was to provide a prompt diagnosis of loculated pericardial hematoma via Fo CUS in the emergency department (ED).

Hepatocardiorenal syndrome in liver cirrhosis:Recognition of a new entity?

Emerging evidence and perspectives have pointed towards the heart playing an important role in hepatorenal syndrome(HRS),outside of conventional understanding that liver cirrhosis is traditionally considered the sole origin of a cascade of pathophysiological mechanisms directly affecting the kidneys in this context.In the absence of established heart disease,cirrhotic cardiomyopathy may occur more frequently in those with liver cirrhosis and kidney disease.It is a specific form of cardiac dysfunction characterized by blunted contractile responsiveness to stress stimuli and altered diastolic relaxation with electrophysiological abnormalities.Despite the clinical description of these potential cardiac-related complications of the liver,the role of the heart has traditionally been an overlooked aspect of circulatory dysfunction in HRS.Yet from a physiological sense,temporality(prior onset)of cardiorenal interactions in HRS and positive effects stemming from portosystemic shunting demonstrated an important role of the heart in the development and progression of kidney dysfunction in cirrhotic patients.In this review,we discuss current concepts surrounding how the heart may influence the development and progression of HRS,and the role of systemic inflammation and endothelial dysfunction causing circulatory dysfunction within this setting.The temporality of heart and kidney dysfunction in HRS will be discussed.For a subgroup of patients who receive portosystemic shunting,the dynamics of cardiorenal interactions following treatment is reviewed.Continued research to determine the unknowns in this topic is anticipated,hopefully to further clarify the intricacies surrounding the liver-heart-kidney connection and improve strategies for management.

Magnetopause properties at the dusk magnetospheric flank from global magnetohydrodynamic simulations,the kinetic Vlasov equilibrium,and in situ observations--Potential implications for SMILE

We derived the properties of the terrestrial magnetopause(MP)from two modeling approaches,one global–fluid,the other local–kinetic,and compared the results with data collected in situ by the Magnetospheric Multiscale 2(MMS2)spacecraft.We used global magnetohydrodynamic(MHD)simulations of the Earth’s magnetosphere(publicly available from the NASA-CCMC[National Aeronautics and Space Administration–Community Coordinated Modeling Center])and local Vlasov equilibrium models(based on kinetic models for tangential discontinuities)to extract spatial profiles of the plasma and field variables at the Earth’s MP.The global MHD simulations used initial solar wind conditions extracted from the OMNI database at the time epoch when the MMS2 observes the MP.The kinetic Vlasov model used asymptotic boundary conditions derived from the same in situ MMS measurements upstream or downstream of the MP.The global MHD simulations provide a three-dimensional image of the magnetosphere at the time when the MMS2 crosses the MP.The Vlasov model provides a one-dimensional local view of the MP derived from first principles of kinetic theory.The MMS2 experimental data also serve as a reference for comparing and validating the numerical simulations and modeling.We found that the MP transition layer formed in global MHD simulations was generally localized closer to the Earth(roughly by one Earth radius)from the position of the real MP observed by the MMS.We also found that the global MHD simulations overestimated the thickness of the MP transition by one order of magnitude for three analyzed variables:magnetic field,density,and tangential speed.The MP thickness derived from the local Vlasov equilibrium was consistent with observations for all three of these variables.The overestimation of density in the Vlasov equilibrium was reduced compared with the global MHD solutions.We discuss our results in the context of future SMILE(Solar wind Magnetosphere Ionosphere Link Explorer)campaigns for observing the Earth’s MP.

融入英国医患沟通模式的眼科专用英语口语工作坊构建

通过介绍中国医患沟通的社会现状,对中英医患沟通培养模式、眼科医疗体系及专用英语课程体系进行对比。从中得出在医疗发展日益国际化的今天,结合中国研究生的教学大纲,以工作坊的形式将英国的医患沟通培养模式融入我国眼科研究生的专用英语口语课符合其职业发展方向。笔者进行三个融入中、英医患沟通能力培养的学术英语口语工作坊构建,提出新的思路:医患沟通能力的培养可以融入医学生任何学习阶段的任何课程中。尽管此类工作坊的实施在当前中国国情下存在诸多困难,但希望本文能为促进此类课堂的研究与推广提供参考依据。

Hepatolithiasis:Epidemiology,presentation,classification and management of a complex disease

The term hepatolithiasis describes the presence of biliary stones within the intrahepatic bile ducts,above the hilar confluence of the hepatic ducts.The disease is more prevalent in Asia,mainly owing to socioeconomic and dietary factors,as well as the prevalence of biliary parasites.In the last century,owing to migration,its global incidence has increased.The main pathophysiological mechanisms involve cholangitis,bile infection and biliary strictures,creating a self-sustaining cycle that perpetuates the disease,frequently characterised by recurrent episodes of bacterial infection referred to as syndrome of“recurrent pyogenic cholangitis”.Furthermore,long-standing hepatolithiasis is a known risk factor for development of intrahepatic cholangiocarcinoma.Various classifications have aimed at providing useful insight of clinically relevant aspects and guidance for treatment.The management of symptomatic patients and those with complications can be complex,and relies upon a multidisciplinary team of hepatologists,endoscopists,interventional radiologists and hepatobiliary surgeons,with the main goal being to offer relief from the clinical presentations and prevent the development of more serious complications.This comprehensive review provides insight on various aspects of hepatolithiasis,with a focus on epidemiology,new evidence on pathophysiology,most important clinical aspects,different classification systems and contemporary management.