A Formulation of the Porous Medium Equation with Time-Dependent Porosity: A Priori Estimates and Regularity Results

We consider a generalized form of the porous medium equation where the porosity ϕis a function of time t: ϕ=ϕ(x,t): ∂(ϕS)∂t−∇⋅(k(S)∇S)=Q(S).In many works, the porosity ϕis either assumed to be independent of (or to depend very little of) the time variable t. In this work, we want to study the case where it does depend on t(and xas well). For this purpose, we make a change of unknown function V=ϕSin order to obtain a saturation-like (advection-diffusion) equation. A priori estimates and regularity results are established for the new equation based in part on what is known from the saturation equation, when ϕis independent of the time t. These results are then extended to the full saturation equation with time-dependent porosity ϕ=ϕ(x,t). In this analysis, we make explicitly the dependence of the various constants in the estimates on the porosity ϕby the introduced transport vector w, through the change of unknown function. Also we do not assume zero-flux boundary, but we carry the analysis for the case Q≡0.

Vulvectomy: Indications and Results in the General Surgery Department of the Ignace Deen Chu Hospital in Conakry

Introduction: The aim of this study was to report the indications and evaluate the results of vulvectomy in the general surgery department of Ignace Deen Hospital, CHU Conakry. Materials and Methods: This was a retrospective descriptive study, conducted over a period of five (05) years from January 1, 2018 to December 31, 2022, in the general surgery department of Ignace Deen Hospital, CHU Conakry. We included in our study all patient records in whom vulvectomy was performed. Results: We recorded 15 cases of vulvectomy out of 453 perineal surgeries, i.e. 3.31%, with a mean age of 43.56 years and extremes of 35 and 69 years. Vulvar cancer was the most common diagnosis (46.67%), followed by Buschke-Lowenstein (33.33%) and anal canal cancer extending to the vulva (20%). Six patients had undergone biopsy (40%). Vulvectomy with lymph node dissection was performed in only 9 patients (60%), and all surgical specimens were sent to anatomical pathology (100%). Conclusion: Vulvectomy is a surgical technique most often indicated for the treatment of vulvar cancer.

How to use the Surveillance,Epidemiology,and End Results(SEER)data:research design and methodology

In the United States(US),the Surveillance,Epidemiology,and End Results(SEER)program is the only comprehensive source of population-based information that includes stage of cancer at the time of diagnosis and patient survival data.This program aims to provide a database about cancer incidence and survival for studies of surveillance and the development of analytical and methodological tools in the cancer field.Currently,the SEER program covers approximately half of the total cancer patients in the US.A growing number of clinical studies have applied the SEER database in various aspects.However,the intrinsic features of the SEER database,such as the huge data volume and complexity of data types,have hindered its application.In this review,we provided a systematic overview of the commonly used methodologies and study designs for retrospective epidemiological research in order to illustrate the application of the SEER database.Therefore,the goal of this review is to assist researchers in the selection of appropriate methods and study designs for enhancing the robustness and reliability of clinical studies by mining the SEER database.

Diagnostic challenges from conflicting results of tests and imaging

Accurate diagnosis is the foundation of clinical care but accurate diagnosis is not easily reached in some cases.In rare instances,even a sophisticated multidisciplinary team at an academic medical center cannot reliably reach an accurate diagnosis after extensive testing and imaging,and has to wait until histological diagnosis or even autopsy results are available.The underlying reason of challenging diagnoses is mostly conflicting data from history,tests,and imaging that point to different diagnoses.In this issue of World Journal of Clinical Cases,Huffaker et al reported such a challenging case of a tricuspid mass in a patient with Li-Fraumeni syndrome.The case by Huffaker et al powerfully illustrates the occasional diagnostic challenges inherent in our current diagnostic approach and the current technology.Clinicians should realize that in rare situations,agnosticism in diagnosis is unavoidable but a treatment has to be initiated so long as the principle of primum non nocere is upheld.

Effect of Types and Orders of Electromagnetic Field Finite Element Meshes on Power Communication Harmonic Parameters Calculation Results of Tubular Hydrogenerators

In generator design field,waveform total harmonic distortion(THD)and telephone harmonic factor(THF)are parameters commonly used to measure the impact of generator no-load voltage harmonics on the power communication quality.Tubular hydrogenerators are considered the optimal generator for exploiting low-head,high-flow hydro resources,and they have seen increasingly widespread application in China's power systems recent years.However,owing to the compact and constrained internal space of such generators,their internal magnetic-field harmonics are pronounced.Therefore,accurate calculation of their THD and THF is crucial during the analysis and design stages to ensure the quality of power communication.Especially in the electromagnetic field finite element modeling analysis of such generators,the type and order of the finite element meshes may have a significant impact on the THD and THF calculation results,which warrants in-depth research.To address this,this study takes a real 34 MW large tubular hydrogenerator as an example,and establishes its electromagnetic field finite element model under no-load conditions.Two types of meshes,five mesh densities,and two mesh orders are analyzed to reveal the effect of electromagnetic field finite element mesh types and orders on the calculation results of THD and THF for such generators.

Parameter calculation and result storage for phase-field simulation in α-Mg dendrite growth of Mg-5-wt% Zn alloy

Parameter calculation and result storage, as two necessary steps in phase-field simulation play an important role in ensuring the accuracy of simulation results. A strategy of parameter calculation and result storage is presented for phase-field simulation in α-Mg dendrite growth of Mg-5-wt% Zn alloy under isothermal solidification. Based on the phase diagram and empirical formulas, key parameters of the phase-field model, such as equilibrium partition coefficient k, liquidus slope m, solutal diffusion coefficient in liquid Dl, and solutal diffusion coefficient in solid Ds, can be obtained.Both structured grid method and structured point method can be used to store simulation results, but using the latter method will reduce about 60% storage space and 37.5% storage time compared with the former. Finally, convergent simulation results of α-Mg dendrite growth are obtained and they are in good agreement with the experimental results about optical micrograph, which verify the accuracy of parameters and stability of storage method.

P&T-Inf: A Result Inference Method for Context-Sensitive Tasks in Crowdsourcing

Context-Sensitive Task(CST)is a complex task type in crowdsourc-ing,such as handwriting recognition,route plan,and audio transcription.The current result inference algorithms can perform well in simple crowd-sourcing tasks,but cannot obtain high-quality inference results for CSTs.The conventional method to solve CSTs is to divide a CST into multiple independent simple subtasks for crowdsourcing,but this method ignores the context correlation among subtasks and reduces the quality of result inference.To solve this problem,we propose a result inference algorithm based on the Partially ordered set and Tree augmented naive Bayes Infer(P&T-Inf)for CSTs.Firstly,we screen the candidate results of context-sensitive tasks based on the partially ordered set.If there are parallel candidate sets,the conditional mutual information among subtasks containing context infor-mation in external knowledge(such as Google n-gram corpus,American Contemporary English corpus,etc.)will be calculated.Combined with the tree augmented naive(TAN)Bayes model,the maximum weighted spanning tree is used to model the dependencies among subtasks in each CST.We collect two crowdsourcing datasets of handwriting recognition tasks and audio transcription tasks from the real crowdsourcing platform.The experimental results show that our approach improves the quality of result inference in CSTs and reduces the time cost compared with the latest methods.

Analysis of Toxicological Test Results of 580 Detergents

To evaluate the safety of detergents,the toxicological test results of 580 collected detergents were analyzed.The results showed that,in the acute oral toxicity test,94.4%and 5.6%of the samples were classified as non-toxic and toxic respectively.In skin irritation test,95.1%of the samples were mild irritation or below,and 4.9%were moderate irritation or above.In the vaginal mucosa irritation test,79.0%of the samples were very mild irritation or below,while 21.0%were mild irritation or above.In the acute inhalation toxicity test,the proportion of the samples classified as actually non-toxic and toxic were 87.9%and 12.1%respectively.In the eye irritation test,95.7%of the samples belonged to mild irritation or below,and 4.3%of the samples belonged to moderate irritation or above.The products at risk in category A,B and C products account for 6.3%,7.7%and 14.2%respectively.Of the 580 tested samples,90.9%were relatively safe,while 9.1%were at risk.These data showed that most of the tested samples meet the safety requirements for use.

Management Results and Financial Status of Rural Collective Economy under the Background of Rural Revitalization

Based on the analysis of financial statements,the performance and problems of rural collective economic organizations in their business activities were analyzed.It is believed that rural collective economy was developing continuously in a good way,with strong debt paying ability,but the operation ability and management efficiency need to be further improved.The operation was too conservative,and the asset utilization efficiency and profitability were weak.There were many unnecessary liabilities,and they developed mainly relying on their own accumulation.Therefore,it is proposed to crack the"talent dilemma"of rural collective economic operation and management,straighten out and clarify the relationship between rural collective economic organizations and villagers self-governing organizations,correctly handle the relationship between collective accumulation and member distribution,adhere to the financial input of blood replenishment and transfusion,and make liabilities reasonable according to the management development.

Vertebroplasty and Kyphoplasty: Indications and Results, a Preliminary Senegalese Experience from the Neurosurgery Department of the CHNU of Fann

Introduction: Vertebroplasty and kyphoplasty are percutaneous techniques that consist in injecting an acrylic cement into the body of a pathological vertebra. This work aims to report the experience the of Fann’s neurosurgery department in treating certain spinal pathologies by vertebroplasty and kyphoplasty. Methods: During a 3-year period from July 1, 2019 to July 31, 2022, we conducted a retrospective, descriptive and analytical study, including patients who underwent vertebroplasty or kyphoplasty for dorsolumbar spinal pathology. Results: The mean age of the 13 patients in our study was 51.61 years. Female gender was predominant in 62% (n = 8). The context of spontaneous onset was found in six patients. Nine patients had a VAS (visual analogue scale) ≥ 8 (69.23%). On clinical examination, all patients had a syndrome without neurological deficits. 84.61% of patients had a CT scan (n = 11). The dorsolumbar hinge was most affected with 53.85% of cases. Seven patients had a vertebral compression of between 25% and. The average degree of kyphosis was 8˚ and seven patients had a degree of kyphosis ≥ 10˚. Tumour aetiology accounted for 46.15% of cases. Kyphoplasty was performed in 61.53% (n = 9) of the cases and vertebroplasty was performed in 38.47% (n = 4) of the patients. Kyphoplasty was associated with biopsy in two cases and with osteosynthesis in one patient. Vertebroplasty was always associated with a biopsy. The evolution was favourable with a significant reduction in pain and vertebral kyphosis. The mean VAS decreased from 8.15 to 0.69 three months after treatment and the mean kyphosis decreased from 8˚ to 2˚. Conclusion: Kyphoplasty and vertebroplasty as percutaneous techniques allow consolidation of the vertebral body and pain relief. Kyphoplasty alone not only reduces pain but also restores the height of the compacted vertebral body.

融入区块链的课程目标达成评价系统建构与应用研究

推进课程评价数字化转型升级,是实现教育现代化、推进教育高质量发展、建设教育强国的重要举措。然而,当前课程目标达成评价领域存在中心化管理、数据孤岛、安全性不足等问题,影响了课程目标达成评价的科学性和公信力,进而制约了课程评价数字化转型。为此,文章提出一种基于区块链技术变革课程评价的新思路,设计了融入区块链的课程目标达成评价系统,从数据共享框架、课程目标达成评价合约、隐私保护方案三个层面探讨系统的运行机制,并阐述该系统的主要功能和应用成效。文章设计的系统,可为消除数据孤岛、提高评价数据安全性、推动课程评价数字化转型提供参考。

成果导向下“精益”教学资源库建设模式的构建与实践

针对高职专业教学资源库建设中资源与岗位对接度不够、资源利用率不高、学习达成度评价体系不全等问题,提出了一种成果导向下的“精益”建设模式。“精益”建设模式以成果为导向,反向设计资源模块,项目式串联建设可复用颗粒化资源,精准化设置学习目标达成评价体系,教师可以基于学情数据,利用资源库资源搭建在线课程,满足不同学习者的学习需求,实现分层次差异化教学。实践表明该模式能有效服务于专业人才培养需求,高效益建设资源库资源,提高学生学习达成度,更好的服务于教师的教学需求,为职业教育资源库提供了一种参考模式。

Results and Application of Soil and Water Conservation Monitoring in the Yellow River Basin

Since water and soil conservation monitoring in the Yellow River Basin entered a new stage at the end of the 20th century,the monitoring scope has been expanding,the monitoring accuracy has been improving,the monitoring content and indicators have been increasing,and the monitoring technology and methods have been improving.This paper mainly analyzes the status of soil and water conservation monitoring in the Yellow River Basin,as well as the construction of the monitoring system and related research,in order to provide a reference for watershed management and development and the scientific research of water and soil conservation.

汽车类专业人才产教融合+OBE理念培养实践——以《汽车电气设备》为例

基于“以学生发展为中心”的教育理念和落实“立德树人”的根本任务,针对《汽车电气设备》课程存在的教学手段单一、思政资源挖掘不深、教学评价体系不完善等教学痛点问题,结合课程特点,从“课程目标确定、教学资源创建、教学内容重塑、教学手段与模式改革、教学评价体系设计”5个方面系统性地实施了教学改革与实践,取得了一系列成效。学生学业成绩、高阶汽车电路分析与设计能力、综合素养不断提升;课程教学成果丰硕。

基于STEAM理念联合PBL教学法在急诊医学教学中的应用研究

目的分析基于STEAM[S(science),T(technology),E(engineering),A(art),M(mathematics)]理念联合以问题为基础的教学法(problem base learning,PBL)在急诊医学教学中应用效果。方法选择2021年6月—2022年6月滨州医学院急诊科80名本临床医学专业实习生为研究对象,将其随机分为对照组、试验组,各40名。对照组接受传统教学,试验组接受基于STEAM理念联合PBL教学法。对比2组教学前后理论知识及实践操作考试成绩、实习生对教学的满意度、学习依从度及教学前后实习生职业特质评分。结果教学前,2组考核成绩对比,差异无统计学意义(P>0.05);教学3个月后,2组基础理论、实践操作考核成绩均明显提升,但试验组提升幅度更大,差异有统计学意义(P<0.001)。试验组实习生学习依从性(97.50%)高于对照组(85.00%),差异有统计学意义(P<0.001)。试验组教学方法、学术能力、带教态度管理质量评分高于对照组,差异有统计学意义(P<0.001)。教学前,2组实习生职业特质评分对比,差异无统计学意义(P>0.05);教学3个月后,试验组评分高于对照组,差异有统计学意义(P<0.001)。结论在急诊医学教学中,基于STEAM理念联合PBL教学法有利于提升实习生的综合能力,提高理论实践成绩和学习依从性。

问题导向与成果导向相融合的钢筋混凝土结构设计原理课程教案设计

综合考虑钢筋混凝土结构设计原理课程章节内容较多的问题,进行合理的课程教案设计是目前较好地教授这门课的方法之一。首先,基于问题导向,总结各章节教学内容需要解决的关键问题;然后,基于成果导向,以问题导向中的各个关键问题为教学成果,开展各个章节的教案设计;最后,将钢筋混凝土结构设计原理课程中的主要章节内容整理成易于教学的教案,从而提升教师的教学能力和提高学生接受知识的能力。问题导向与成果导向相融合的教案设计方法可为土木工程专业其他相关课程的教案设计提供参考。

翻转课堂联合PBL教学法在口腔医学教学中的应用

目的 探讨翻转课堂联合以问题为基础的教学法(problem based learning,PBL)在口腔医学教学中的应用效果。方法 选择2021年1月—2022年12月2018、2019级本科学生共94名作为教学研究对象,将本科学生根据教学设计分为对照组与观察组,各47名。对照组采用传统教学模式教学,观察组则采用翻转课堂联合PBL教学法,2组均进行连续3个月的教学。比较2组教学考核成绩、教学效果、学生综合能力及教学满意度。结果 观察组带教3个月后理论考核为(92.52±5.41)分、技能考核中病史采集为(91.15±5.24)分、病例分析为(90.69±5.16)分及体格检查为(93.27±6.42)分,高于对照组的(85.15±4.39)分、(83.27±4.12)分、(84.12±4.52)分、(85.24±6.11)分(P <0.05);观察组教学3个月后学生积极性及兴趣为(91.15±4.69)分、知识理解能力为(89.83±4.51)分、自主学习能力提高为(92.32±5.34)分、团队协作能力为(94.57±5.41)分及临床思维模式建立评分为(93.23±6.26)分,高于对照组的(85.41±3.25)分(、82.17±3.13)分(、84.43±4.39)分、(85.53±4.34)分、(88.21±5.42)分(P <0.05);观察组教学3个月后科研能力、创新能力、思维能力、沟通能力、设计分析能力、独立解决问题能力评分高于对照组(P<0.05);观察组教学3个月后教学满意度高于对照组(P<0.05)。结论 翻转课堂联合PBL教学法用于口腔医学教学中有助于提高学生考核成绩,提升学生综合分析能力及团队协作能力,可获得较高的教学满意度。

案例教学法在神经外科临床实践技能教学中的应用

目的探讨在神经外科临床实践技能教学中采取案例教学法进行教学的效果。方法选取2021年1月至2022年12月苏州大学附属第一医院神经外科临床实习的80名学生为研究对象,将2021学年度采取传统教学法的40名学生纳入对照组,将2022学年度采取案例教学法的40名学生纳入研究组,对比考核成绩、教学满意度评价。结果研究组理论考核、临床知识、病例分析评分较对照组高,差异有统计学意义(P<0.001);研究组基础知识理解、重点内容掌握、教学模式可行、学习兴趣、课堂气氛、教师教学热情以及师生互动评分均较对照组高,差异有统计学意义(P<0.001)。结论在神经外科临床实践技能教学中采取案例教学法可提高教学效果,提升学生的理论知识与操作技能,学生对教学满意度评价较高。

结果第一重要?高校学科评估价值取向的深层反思——兼论学科评估的模式创新

高校学科评估对促进高校学科建设具有不可替代的作用。高校及学科团队等建设主体对现行学科评估持有的“结果第一重要”价值取向,导致学科发展出现生态失衡和同质化等负面效应。产生问题的表层原因是建设主体站在了功利目的一边,深层原因是数数和排名等计量操作模式所致。认清学科评估不存在固定标准和绝对结果的本质特征,揭示学科评估的主要职能在于促进高校学科生态系统和成果发现机制的建设。提出构建以发挥建设主体自组织功能为主的新型评估模式的设想,真正实现“以评促建”的评估目的。

国有上市公司国资监管与证券监管的制度协调研究

国有上市公司既具有上市公司属性、又具有国有属性,需同时遵守证券监管和国资监管的双重规则,而这双重规则之间可能存在冲突,造成国有上市公司治理违规的风险。这种冲突源于监管价值目标的差异:证券监管基于中小投资者保护的立场注重上市公司独立,而国资监管基于保障国有经济功能、维护国资经营安全的特性强调国有投资方的管控。对于身处交叉监管下的国有上市公司而言,解决冲突的根本路径在于分别从国资监管和证券监管两个维度进行制度矫正与协调。就国资监管而言,应切实从制度层面实现“管资产”到“管股权”的转变;就证券监管而言,则应正视国资监管的合理需求,以适度监管为原则,并确立结果导向的监管理念,在不实质损害资本市场中小投资者利益的情况下,对国资监管规则予以适当认可。