期刊文献+
共找到3,555篇文章
< 1 2 178 >
每页显示 20 50 100
Colonoscopy-assisted removal of an impaction foreign body at the rectosigmoid junction: A case report
1
作者 Peng-Fei Zhou Jin-Gen Lu +1 位作者 Jia-Dong Zhang Jia-Wen Wang 《World Journal of Clinical Cases》 SCIE 2024年第11期1990-1995,共6页
BACKGROUND When an anorectal foreign body is found,its composition and shape should be evaluated,and a timely and effective treatment plan should be developed based on the patient's symptoms to avoid serious compl... BACKGROUND When an anorectal foreign body is found,its composition and shape should be evaluated,and a timely and effective treatment plan should be developed based on the patient's symptoms to avoid serious complications such as intestinal perforation caused by displacement of the foreign body.CASE SUMMARY A 54-year-old male was admitted to our outpatient clinic on June 3,2023,due to a rectal foreign body that had been embedded for more than 24 h.The patient reported using a glass electrode tube to assist in the recovery of prolapsed hemorrhoids,however,the electrode tube was inadvertently inserted into the anus and could not be removed by the patient.During hospitalization,the patient underwent surgery,and the foreign body was dragged into the rectum with the aid of colonoscopy.The anus was dilated with a comb-type pulling hook and an anal fistula pulling hook to widen the anus and remove the foreign body,and the local anal symptoms were then relieved with topical drugs.The patient was allowed to eat and drink,and an entire abdominal Computed tomography(CT)and colonoscopy were reviewed 3 d after surgery.CT revealed no foreign body residue and colonoscopy showed no metal or other residues in the colon and rectum,and no apparent intestinal tract damage.CONCLUSION The timeliness and rationality of the surgical and therapeutic options for this patient were based on a literature review of the clinical signs and conceivable conditions in such cases.The type,material and the potential risks of rectal foreign bodies should be considered. 展开更多
关键词 Foreign body impaction Surgical therapy Rectum-sigmoid colon COLONOSCOPY Case report
下载PDF
Nursing Practice for a Case of Acute Left Heart Failure Complicated with Colonic Impaction
2
作者 Mingzhen Liu Li Zhang +2 位作者 Fenyan Wang Zhiyuan Teng Li Zhu 《Journal of Biosciences and Medicines》 2024年第7期100-107,共8页
Research Background: Heart failure is a type of organic heart disease caused by excessive ventricular load, leading to insufficient myocardial contractility and decreased cardiac output in the body. With the progressi... Research Background: Heart failure is a type of organic heart disease caused by excessive ventricular load, leading to insufficient myocardial contractility and decreased cardiac output in the body. With the progression of the patient's condition, gastrointestinal dysfunction is frequently complicated. At the same time, the accumulation of feces in the body (colonic impaction) can also increase the burden on the patient’s heart, triggering or exacerbating the occurrence or progression of heart failure. Purpose: this article focuses on the correlation between colonic impaction and heart failure, using the nursing experience of a case of acute left heart failure complicated by colonic impaction as an example, in order to provide clinical evidence for the care of patients with colonic impaction combined with heart failure in the future. Method: By using innovative thinking, the stomach tube is used to replace the enema tube, which is inserted through the anus to reach the end of the colon. By combining acupressure at points such as Zhongwan, Tianzhu, and Guanyuan, it helps promote the elimination of fecal impaction. Conclusion: This case reflects the innovative thinking and adaptability of nurses, providing a new clinical approach for the aggravation of the condition of long-term heart failure patients due to constipation issues. Further research in clinical practice is warranted. 展开更多
关键词 Heart Failure Colonic impaction Acupoint Massage ENEMA
下载PDF
Is metaphyseal ulnar shortening osteotomy superior to diaphyseal ulnar shortening osteotomy in the treatment of ulnar impaction syndrome?A meta-analysis
3
作者 Hai-Lin Deng Ming-Ling Lu +2 位作者 Zhe-Ming Tang Qing-Long Mao Jin-Min Zhao 《World Journal of Clinical Cases》 SCIE 2023年第12期2753-2765,共13页
BACKGROUND Although metaphyseal ulnar shortening osteotomy(MUSO)is safer for the treatment of ulnar impaction syndrome(UIS)than diaphyseal ulnar shortening osteotomy(DUSO),DUSO is widely used for UIS treatment.AIM To ... BACKGROUND Although metaphyseal ulnar shortening osteotomy(MUSO)is safer for the treatment of ulnar impaction syndrome(UIS)than diaphyseal ulnar shortening osteotomy(DUSO),DUSO is widely used for UIS treatment.AIM To evaluate the effectiveness of DUSO and MUSO for UIS treatment and determine the factors that should be considered when choosing surgical treatment for UIS.METHODS Articles comparing the effectiveness of DUSO and MUSO for UIS treatment were systematically retrieved from MEDLINE(Ovid),PubMed,EMBASE,and Cochrane Library.The demography,incidence of complications,secondary operation rate,postoperative DASH score,wrist pain on the visual analogue scale,and grip strength improvement were also evaluated.In addition,the correlation between the improvement of grip strength and the shortening of osteotomy length of ulna was analyzed.The outcome of the patient was discontinuous,and the odds ratio,risk ratio(RR),and 95%CI were calculated and analyzed via RevMan5.3 software.RESULTS Six studies,including 83 patients receiving MUSO(experimental group)and 112 patients receiving DUSO(control group),were included in the meta-analysis.The second operation rate was significantly higher after DUSO than after MUSO.The DASH scores were slightly lower in the MUSO group than in the DUSO group.The patients receiving MUSO had slightly better pain relief effect than patients receiving DUSO.However,the incidence of complications and improvement of grip strength were not significantly different between the two groups.CONCLUSION Although DUSO and MUSO provide similar effects for UIS,MUSO is associated with a lower secondary operation rate,slightly lower postoperative DASH scores and slightly better pain relief effect than DUSO,indicating that MUSO can effectively be used for UIS treatment. 展开更多
关键词 Metaphyseal Diaphyseal Ulnar shortening osteotomy Ulnar impaction syndrome Metaanalysis
下载PDF
High attenuation mucoid impaction in allergic bronchopulmonary aspergillosis 被引量:9
4
作者 Ritesh Agarwal 《World Journal of Radiology》 CAS 2010年第1期41-43,共3页
Allergic bronchopulmonary aspergillosis(ABPA) is a complex hypersensitivity syndrome triggered against antigens of Aspergillus fumigatus,a fungus that most commonly colonizes the airways of patients with bronchial ast... Allergic bronchopulmonary aspergillosis(ABPA) is a complex hypersensitivity syndrome triggered against antigens of Aspergillus fumigatus,a fungus that most commonly colonizes the airways of patients with bronchial asthma and cystic fibrosis.It presents clinically with refractory asthma,hemoptysis and systemic manifestations including fever,malaise and weight loss.Radiologically,it presents with central bronchiectasis and recurrent episodes of mucus plugging.The mucus plugs in ABPA are generally hypodense but in up to 20% of patients the mucus can be hyperdense on computed tomography.This paper reviews the literature on the clinical significance of hyperattenuated mucus in patients with ABPA. 展开更多
关键词 Allergic BRONCHOPULMONARY ASPERGILLOSIS Mucoid impaction Hyperdense MUCUS HIGH ATTENUATION MUCUS Aspergillus
下载PDF
Results of the open surgery after endoscopic basket impaction during ERCP procedure 被引量:2
5
作者 Sezgin Yilmaz Ogun Ersen +7 位作者 Taner Ozkececi Kadir S Turel Serdar Kokulu Emre Kacar Murat Akici Murat Cilekar Ozgur Kavak Yuksel Arikan 《World Journal of Gastrointestinal Surgery》 SCIE CAS 2015年第2期15-20,共6页
AIM:To report the results of open surgery for patients with basket impaction during endoscopic retrograde cholangiopancreatography(ERCP) procedure.METHODS: Basket impaction of either classical Dormia basket or mechani... AIM:To report the results of open surgery for patients with basket impaction during endoscopic retrograde cholangiopancreatography(ERCP) procedure.METHODS: Basket impaction of either classical Dormia basket or mechanical lithotripter basket with an entrapped stone occurred in six patients.These patients were immediately operated for removal of stone(s) and impacted basket.The postoperative course,length of hospital stay,diameter of the stone,complication and the surgical procedure of the patients were reported retrospectively.RESULTS: Six patients(M/F,0/6) were operated due to impacted basket during ERCP procedure.The mean age of the patients was 64.33 ± 14.41 years.In all cases the surgery was performed immediately after the failed ERCP procedure by making a rightsubcostal incision.The baskets containing the stone were removed through longitudinal choledochotomy with the stone.The choledochotomy incisions were closed by primary closure in four patients and T tube placement in two patients.All patients were also performed cholecystectomy additionally since they had cholelithiasis.In patients with T-tube placement it was removed on the 13 th day after a normal T-tube cholangiogram.The patients remained stable at postoperative period and discharged without any complication at median 7 d.CONCLUSION: Open surgical procedures can be applied in patients with basket impaction during ERCP procedure in selected cases. 展开更多
关键词 BILIARY STONE ENDOSCOPIC RETROGRADE CHOLANGIOPANCREATOGRAPHY Basket impaction Surgery
下载PDF
Food impaction in older age:Think about an eosinophilic esophagitis 被引量:2
6
作者 Umit Akyüz Filiz Akyüz +3 位作者 Kamil zdil Hasan Altun Ahmet Faruk Agan Aysegül Agan 《World Journal of Gastrointestinal Endoscopy》 CAS 2013年第2期79-80,共2页
Eosinophilic esophagitis is an inflammatory condition of esophagus.It is generally seen in childhood and young population.Men are more commonly affected than women.However,it is not common in an advanced age.Eosinophi... Eosinophilic esophagitis is an inflammatory condition of esophagus.It is generally seen in childhood and young population.Men are more commonly affected than women.However,it is not common in an advanced age.Eosinophilic esophagitis decreases the ability of the esophagus to stretch and accommodation against foods.Therefore,the major symptom in adults with eosinophilic esophagitis is difficulty in swallowing solid food(dysphagia).Specifically,the food gets stuck in the esophagus after it is swallowed.Less common symptoms include heartburn and chest pain.Because of this,it may be incorrectly diagnosed as a gastroesophageal reflux disease.Here,we reported a case presented with food impaction at advanced age.As a conclusion,eosinophilic esophagitis is a rare entity that must be remembered in advance aged patients presenting with food impaction. 展开更多
关键词 DYSPHAGIA EOSINOPHILIA ESOPHAGITIS Food impaction ALLERGY
下载PDF
Acetabular Reconstruction with Massive Allograft Shaped to the Cavity and Kerboull-Type Acetabular Reinforcement Device for Multiple Failures of Impaction Bone Graft: A Case Report 被引量:2
7
作者 Takaya Taniguchi Mayumi Sonekatsu +3 位作者 Wataru Taniguchi Erabu Miyamoto Takahide Sasaki Munehito Yoshida 《Open Journal of Orthopedics》 2017年第1期14-20,共7页
Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the aceta... Acetabular component revision in the presence of severe bone loss is difficult for reconstructing an acetabular component in the anatomical hip center. Various treatment options are available, although often the acetabular defect cannot be corrected with a single option alone. Precise assessment of the bone loss and a suitable combination of methods are needed. Here we report a case of multiple failures with impaction bone grafting reconstruction for an acetabular bone defect of American Academy of Orthopedic Surgeons classification type III. We finally reconstructed the acetabulum with three femoral head allografts and a Kerboull-type acetabular reinforcement device. The allograft was a casted, jet-type helmet-like shape. A year later the patient was able to walk without a cane and perform light agricultural work. Accurate evaluation of the acetabular bone loss and appropriate reconstruction is important. 展开更多
关键词 ACETABULAR Reconstruction BONE Defect ALLOGRAFT KT Plate impaction BONE GRAFT
下载PDF
Femoral impaction grafting
8
作者 John A Scanelli Thomas E Brown 《World Journal of Orthopedics》 2013年第1期7-11,共5页
Femoral impaction grafting is a reconstruction option applicable to both simple and complex femoral component revisions. It is one of the preferred techniques for reconstructing large femoral defects when the isthmus ... Femoral impaction grafting is a reconstruction option applicable to both simple and complex femoral component revisions. It is one of the preferred techniques for reconstructing large femoral defects when the isthmus is non-supportive. The available level of evidence is primarily derived from case series, which shows a mean survivorship of 90.5%, with revision or re-operation as the end-point, with an average follow-up of 11 years. The rate of femoral fracture requiring re-operation or revision of the component varies between several large case series, ranging from 2.5% to 9%, with an average of 5.4%. 展开更多
关键词 FEMORAL impaction GRAFTING FEMORAL REVISION BONE GRAFTING REVISION total hip ARTHROPLASTY BONE loss
下载PDF
Mandibular changes associated with maxillary impaction and molar intrusion
9
作者 Sondos Abuzinada Fahad Alsulaimani 《Open Journal of Stomatology》 2013年第9期515-519,共5页
We report a case series of ten patients who presented with anterior open bite. The initial evaluation included clinical pictures, lateral cephalometric radiographs and dental casts. They were assessed according to the... We report a case series of ten patients who presented with anterior open bite. The initial evaluation included clinical pictures, lateral cephalometric radiographs and dental casts. They were assessed according to the severity of the open bite and the cause (skeletal or dental). They all underwent orthodontic treatment as an initial step. Five patients with dental open bite underwent molar intrusion using titanium screws and five patients underwent maxillary Le Fort I impaction. We report the mandibular changes associated with these different treatment modalities with improved esthetics. 展开更多
关键词 MAXILLARY impaction MOLAR Intrusion Open BITE Le FORT I Titanium Screws
下载PDF
The Utility of Diagnostic Imaging in Fish Bone Impaction
10
作者 Shanesh Kumar Casey Yu +3 位作者 Jason Toppi Matthew Ng Fiona Hill Natalie Sist 《Open Journal of Radiology》 2018年第1期45-52,共8页
Objectives: The purpose of this pilot study was to obtain an Australian perspective on evaluating the utility of plain film radiography and computed tomography (CT) to rule out fish bone impaction in the upper aerodig... Objectives: The purpose of this pilot study was to obtain an Australian perspective on evaluating the utility of plain film radiography and computed tomography (CT) to rule out fish bone impaction in the upper aerodigestive tract in the emergency department (ED) setting. Methods: A retrospective multicentre cohort study was conducted. A total of 73 patients met the inclusion criteria. A subgroup of patients underwent CT. We studied the sensitivity and specificity of x-ray and CT along with other demographic variables to determine the likelihood of true fish bone impaction. Results: Out of the 73 patients, 28 patients had true bone impaction. The sensitivity for x-ray was 42.9% and specificity was 73.3%. The sensitivity of CT was 87.5% and specificity was 71.4%. We found a significant difference in the mean age of presentation for true bone and false bone impaction, P = 0.02. Conclusion: Due to the low sensitivity of x-ray we do not recommend the utilisation of plain film radiography to rule out bone impaction Advances in low dose radiation multidetector CT scanners may replace plain film radiography as a screening tool. 展开更多
关键词 FISH BONE impaction EMERGENCY ENT X-Ray COMPUTED Tomography
下载PDF
Prevalence of Canine Impaction among Saudi Population at Al Qassim Area in the Kingdom of Saudi Arabia
11
作者 Sumayah Fahad Alhumaid Zainab Wajih Aljishi +2 位作者 Fathma Fahad Alribdi Hessah Khaled Aldhubaiy Abeer Ibrahim AlGhfaili 《Open Journal of Clinical Diagnostics》 2020年第4期115-123,共9页
<b>Background:</b> One of the most reported dental problems is a tooth impaction which is defined as the infraosseous position of the tooth after the estimated time of eruption [1]. Thus, the most notable ... <b>Background:</b> One of the most reported dental problems is a tooth impaction which is defined as the infraosseous position of the tooth after the estimated time of eruption [1]. Thus, the most notable tooth impaction is canine impaction which is a frequently encountered clinical problem. <b>Aim:</b> This study aimed to determine the prevalence of impacted canines among Saudi people from the 5-year period of 2013-2018 in Al Qassim area in the KSA. <b>Methodology:</b> A retrospective research designed was utilized in the study. A retrospective study simply means to “look back” in the past and usually done by obtaining data from medical records of the targeted population with common characteristics [2]. <b>Results:</b> This 5-year study covered year 2013 to 2018. In this study, there were 1500 who seek dental health in King Fahd Specialist Hospital. Thus, out of these clients, only 89 were identified with cases of impacted canine using the OPG with a prevalence rate of 5.9 %. In addition, it was found that out of 89 patients identified, the patients have impacted canines in different locations: maxillary, mandible, right side and left side. It was found that there were 187 impacted teeth in different locations among 89 clients affected. There were 48 cases (25.7%) of impacted canines on the right side while 64 cases (34.2%) were reported on the left side of the total group. Moreover, impacted maxillary canine were 68 cases (36.4%) and mandibular impacted canine were only 7 cases (3.7%) of the total group. <b>Conclusion:</b> The early detection and treatment approach of impacted canines among affected individuals is vital in order to prevent different problems that may arise during impaction of canine teeth. Awareness, early detection, proper diagnostic test and multiple treatment approaches are needed to prevent different sequelae due to canine impaction. 展开更多
关键词 Canine impaction Dental Health Maxillary and Mandibular
下载PDF
Application of 3D Projection Profilometry in the High Speed Impaction Surface Deformation Measurement Research
12
作者 Eryi Hu 《Journal of Signal and Information Processing》 2020年第4期103-115,共13页
In order to study the strength of the composite material plate problems, need to adopt a nondestructive testing method to obtain the specimen surface under the effect of high-speed impact regularity of shape. The proj... In order to study the strength of the composite material plate problems, need to adopt a nondestructive testing method to obtain the specimen surface under the effect of high-speed impact regularity of shape. The projection profilometry was used to measure the surface profile or the full field deformation. Furtherly, by using the Fourier transform algorithm, there is only one frame of captured image</span><span style="font-family:Verdana;"> which</span><span style="font-family:Verdana;"> is needed in the measurement, so that it can be introduced into the high speed impaction procedure measurement. An experimental system, which was contained with an impact setup and the projection profilometry measurement part, was constructed for the impaction action characteristic research. The metallic impact object can be launched by a gas gun or a spin fan, respectively. The detected object </span><span style="font-family:Verdana;">is</span><span style="font-family:Verdana;"> manufactured by composite materials. In order to increase the surface deformation measurement accuracy, the calibration method and the error was discussed with different calibration specimen. And then, the proposed profilometry measurement method is proved by the gas gun and spin fan projectile test. The surface deformation of the manufactured composite plates and fan case are measured in the impaction procedure. So that the impact action details can be described much more clearly than the traditional video monitoring method. 展开更多
关键词 Projection Profilometry Fourier Transform Algorithm Deformation Measurement impaction Monitoring
下载PDF
Novel use of esophageal overtube and water flushes as a safety indicator and facilitator for the push technique in esophageal food impaction
13
作者 Paul P Shao Jasleen K Grewal Adam M Custer 《Discussion of Clinical Cases》 2020年第1期8-11,共4页
Esophageal food impaction requires urgent endoscopic intervention either by extraction or pushing into the stomach.Due to risks of perforation,controversy exists between when to extract verses when to push the food bo... Esophageal food impaction requires urgent endoscopic intervention either by extraction or pushing into the stomach.Due to risks of perforation,controversy exists between when to extract verses when to push the food bolus.There are no clear guidelines on when it is safe to push a food bolus;endoscopists rely on their subjective experiences and judgment.We present a case with a novel use of an esophageal overtube and water flushes to determine the safety of pushing a food bolus and facilitate passage into the stomach. 展开更多
关键词 Esophageal food impaction Esophageal foreign body EGD DYSPHAGIA EGD push technique
下载PDF
Clinical observation of bone graft impaction on posterior intervertebral body fusion for lumbar spondylolisthesis
14
作者 唐向盛 《外科研究与新技术》 2011年第2期92-92,共1页
Objective To investigate the clinical effect of bone graft impaction on posterior intervertebral fusion for lumbar spondylolisthesis.Methods From January 2001 to July 2008,36 patients with lumbar spondylolisthesis wer... Objective To investigate the clinical effect of bone graft impaction on posterior intervertebral fusion for lumbar spondylolisthesis.Methods From January 2001 to July 2008,36 patients with lumbar spondylolisthesis were treated by 展开更多
关键词 BONE JOA Clinical observation of bone graft impaction on posterior intervertebral body fusion for lumbar spondylolisthesis
下载PDF
Impaction of a lithotripsy basket during endoscopic lithotomy of a common bile duct stone 被引量:4
15
作者 Nobutada Fukino Takatsugu Oida +4 位作者 Atsushi Kawasaki Kenji Mimatsu Youichi Kuboi Hisao Kano Sadao Amano 《World Journal of Gastroenterology》 SCIE CAS CSCD 2010年第22期2832-2834,共3页
The treatments for common bile duct (CBD) stones are being continually developed. Impaction of the lithotripsy basket during endoscopic removal of CBD stones was seen in 5.9% patients. We report the case of a 66-yearo... The treatments for common bile duct (CBD) stones are being continually developed. Impaction of the lithotripsy basket during endoscopic removal of CBD stones was seen in 5.9% patients. We report the case of a 66-yearold woman who underwent surgery for the removal of an impacted biliary basket. She was admitted to our hospital with a complaint of right upper abdominal pain. Magnetic resonance cholangiopancreatography revealed a CBD stone (20 mm × 15 mm). We diagnosed her with choledocholithiasis and performed endoscopic retrograde cholangiopancreatography to remove the stone. However, unfortunately, the retrievable basket around the stone became impacted. An endotriptor along with forceps could not be used owing to the entrapment of the basket, and thus we performed urgent surgery. The basket containing the stone was removed through a longitudinal choledochotomy. The wires leading to the basket were cut, and the basket containing the stone was removed via the incision. A T-tube was inserted,and the choledochotomy was closed. The postoperative course was uneventful. In conclusion, if the diameter of a CBD stone is more than 20 mm, then the risk of basket impaction increases, and surgery may be necessary as the initial treatment of the CBD stone. 展开更多
关键词 Common bile duct gallstones Impacted biliary basket LITHOTRIPSY
下载PDF
Vertical direction impaction of kissing molars:A case report 被引量:1
16
作者 Cai Wen Rong Jiang +4 位作者 Zhi-Qiang Zhang Bo Lei Yuan-Zheng Yan Ying-Quan Zhong Long Tang 《World Journal of Clinical Cases》 SCIE 2022年第12期3959-3965,共7页
BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction ... BACKGROUND Kissing molars(KMs)are a scarcely reported form of molar impaction in which the occlusal surfaces contact each other within a single dental follicle and the roots point in opposite directions.The direction of KMs impaction is generally tilted.KMs with vertical direction impaction have not been reported in the literature.CASE SUMMARY A 25-year-old female visited a dentist for right maxillary wisdom teeth extraction and was diagnosed with two vertically impacted KMs in the left mandible on panoramic radiography.After cone-beam computed tomography examination confirmed no secondary complication,the patient chose to undergo observation and regular follow-up.A literature review of KMs revealed that vertical impacted KMs are rare;high-quality evidence regarding their prevalence is still lacking.At present,the causality of KMs is controversial.In this study,we have tried to provide a detailed definition of KMs to allow an accurate evaluation of their prevalence and classification based on their impaction direction which may be related to their pathogenesis.The treatment plan of KMs depends on the condition and location of the affected teeth and associated complications;they may be either directly extracted or treated using a multidisciplinary approach including maxillofacial surgeons and orthodontists.CONCLUSION KMs are a rare clinical condition of impacted teeth with unclear pathogenesis.Vertically impacted KMs were seldom reported.Reasonable definition and classification of KMs can help in the understanding of their causes and prevalence. 展开更多
关键词 Kissing molars Impacted tooth PATHOGENESIS PREVALENCE Classification Case report
下载PDF
美国教师评估与退出机制的构建及其启示:基于对IMPACT教师评估系统的剖析
17
作者 王莹 任霞 《成都师范学院学报》 2024年第4期43-54,共12页
为探索我国教师评估与退出机制的建立与运行,采用文本分析方法对美国华盛顿哥伦比亚特区IMPACT评估系统操作指南进行分析,总结IMPACT评估系统的运行体系与特点,为我国教师评估与退出机制提供借鉴。IMPACT评估系统通过覆盖全体的评估对... 为探索我国教师评估与退出机制的建立与运行,采用文本分析方法对美国华盛顿哥伦比亚特区IMPACT评估系统操作指南进行分析,总结IMPACT评估系统的运行体系与特点,为我国教师评估与退出机制提供借鉴。IMPACT评估系统通过覆盖全体的评估对象、专业多元的评估责任主体、丰富具体的评估内容、清晰透明的评估流程以及奖罚分明的评估结果对华盛顿特区公立学校系统教师进行评估,整个系统呈现出评估内容专业化、评估过程公正化、评估结果差异化和评估系统动态化等特点。综观IMPACT评估系统的设计与运行,我国在构建教师评估与退出机制时,应注意在体系建设上强调政府提供制度支持;在评估内容与标准上关注教师能力;在评估责任主体上要兼顾多方利益群体;在系统设计上要因地制宜;最后在系统实施过程中更要注重宽严适度。 展开更多
关键词 IMPACT教师评估系统 华盛顿哥伦比亚特区公立学校系统 教育评估 教师队伍建设 教师退出机制 美国教师
下载PDF
The impact of demographic dynamics on food consumption and its environmental outcomes:Evidence from China 被引量:2
18
作者 Shaoting Li Xuan Chen +1 位作者 Yanjun Ren Thomas Glauben 《Journal of Integrative Agriculture》 SCIE CAS CSCD 2024年第2期414-429,共16页
With increasing population and changing demographics,food consumption has experienced a significant transition in quantity and quality.However,a dearth of knowledge remains regarding its environmental impacts and how ... With increasing population and changing demographics,food consumption has experienced a significant transition in quantity and quality.However,a dearth of knowledge remains regarding its environmental impacts and how it responds to demographic dynamics,particularly in emerging economies like China.Using the two-stage Quadratic Almost Demand System(QUAIDS)model,this study empirically examines the impact of demographic dynamics on food consumption and its environmental outcomes based on the provincial data from 2000 to 2020 in China.Under various scenarios,according to changes in demographics,we extend our analysis to project the long-term trend of food consumption and its environmental impacts,including greenhouse gas(GHG)emissions,water footprint(WF),and land appropriation(LA).The results reveal that an increase in the proportion of senior people significantly decreases the consumption of grain and livestock meat and increases the consumption of poultry,egg,and aquatic products,particularly for urban residents.Moreover,an increase in the proportion of males in the population leads to higher consumption of poultry and aquatic products.Correspondingly,in the current scenario of an increased aging population and sex ratio,it is anticipated that GHG emissions,WF,and LA are likely to decrease by 1.37,2.52,and 3.56%,respectively.More importantly,in the scenario adhering to the standards of nutritional intake according to the Dietary Guidelines for Chinese Residents in 2022,GHG emissions,WF,and LA in urban areas would increase by 12.78,20.94,and 18.32%,respectively.Our findings suggest that changing demographics should be considered when designing policies to mitigate the diet-environment-health trilemma and achieve sustainable food consumption. 展开更多
关键词 demographic dynamics food consumption environmental impacts nutrition intakes
下载PDF
Enhanced structural damage behavior of liquid-filled tank by reactive material projectile impact 被引量:1
19
作者 Jianwen Xie Yuanfeng Zheng +4 位作者 Zhenyang Liu Chengzhe Liu Aoxin Liu Pengwan Chen Haifu Wang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第1期211-229,共19页
A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RMPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAM) was s... A series of ballistic experiments were performed to investigate the damage behavior of high velocity reactive material projectiles(RMPs) impacting liquid-filled tanks,and the corresponding hydrodynamic ram(HRAM) was studied in detail.PTFE/Al/W RMPs with steel-like and aluminum-like densities were prepared by a pressing/sintering process.The projectiles impacted a liquid-filled steel tank with front aluminum panel at approximately 1250 m/s.The corresponding cavity evolution characteristics and HRAM pressure were recorded by high-speed camera and pressure acquisition system,and further compared to those of steel and aluminum projectiles.Significantly different from the conical cavity formed by the inert metal projectile,the cavity formed by the RMP appeared as an ellipsoid with a conical front.The RMPs were demonstrated to enhance the radial growth velocity of cavity,the global HRAM pressure amplitude and the front panel damage,indicating the enhanced HRAM and structural damage behavior.Furthermore,combining the impact-induced fragmentation and deflagration characteristics,the cavity evolution of RMPs under the combined effect of kinetic energy impact and chemical energy release was analyzed.The mechanism of enhanced HRAM pressure induced by the RMPs was further revealed based on the theoretical model of the initial impact wave and the impulse analysis.Finally,the linear correlation between the deformation-thickness ratio and the non-dimensional impulse for the front panel was obtained and analyzed.It was determined that the enhanced near-field impulse induced by the RMPs was the dominant reason for the enhanced structural damage behavior. 展开更多
关键词 Reactive material projectile Hydrodynamic ram Enhanced structural damage Liquid-filled tank Impact
下载PDF
The coupling control of biological precursors and environmental factors onβ-carotane enrichment in alkaline lacustrine source rocks:A case study from the Fengcheng formation in the western Junggar Basin,NW China 被引量:1
20
作者 Mao-Guo Hou Ming Zha +5 位作者 Hua Liu Hai-Lei Liu Jiang-Xiu Qu Ablimit Imin Xiu-Jian Ding Zhong-Fa Jiang 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期836-854,共19页
The organic-rich mudstones and dolostones of the Permian Fengcheng Formation(Fm.)are typically alkaline lacustrine source rocks,which are typified by impressively abundantβ-carotane.Abundant β-carotane has been well... The organic-rich mudstones and dolostones of the Permian Fengcheng Formation(Fm.)are typically alkaline lacustrine source rocks,which are typified by impressively abundantβ-carotane.Abundant β-carotane has been well acknowledged as an effective indicator of biological sources or depositional environments.However,the specific biological sources of β-carotane and the coupling control of biological sources and environmental factors on the enrichment of β-carotane in the Fengcheng Fm.remains obscure.Based on a comprehensive investigation of the bulk,molecular geochemistry,and organic petrology of sedimentary rocks and the biochemistry of phytoplankton in modern alkaline lakes,we proposed a new understanding of the biological precursors of β-carotane and elucidated the enrichment mechanism of β-carotane in the Fengcheng Fm.The results show that the biological precursors crucially control the enrichment of β-carotane in the Fengcheng Fm.The haloalkaliphilic cyanobacteria are the primary biological sources of β-carotane,which is suggested by a good positive correlation between the 2-methylhopane index,7-+8-methyl heptadecanes/C_(max),C_(29%),and β-carotane/C_(max)in sedimentary rocks and the predominance of cyanobacteria with abundantβ-carotene in modern alkaline lakes.The enrichment of β-carotane requires the reducing condition,and the paleoredox state that affects the enrichment of β-carotane appears to have a threshold.The paleoclimate conditions do not considerably impact the enrichment of β-carotane,but they have some influence on the water's paleosalinity by affecting evaporation and precipitation.While it does not directly affect the enrichment of β-carotane in the Fengcheng Fm.,paleosalinity does have an impact on the cyanobacterial precursor supply and the preservation conditions. 展开更多
关键词 β-carotane enrichment Cyanobacterial input Environmental impact Alkaline lacustrine source rocks The Fengcheng formation
下载PDF
上一页 1 2 178 下一页 到第
使用帮助 返回顶部