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Application Research of Fragmented Case Teaching in Standardized Training of Residents in Anesthesiology Department
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作者 Xiaokai Zhou Jian Shen 《Journal of Clinical and Nursing Research》 2023年第5期1-6,共6页
Objective:To explore the effect of fragmented case teaching in the standardized training of residents in anesthesiology department.Methods:80 doctors who participated in the standardized training of residents in anest... Objective:To explore the effect of fragmented case teaching in the standardized training of residents in anesthesiology department.Methods:80 doctors who participated in the standardized training of residents in anesthesiology department from January 2021 to January 2022 were selected as the research objects,and the 80 doctors were divided into experimental groups according to the clinical teaching mode(n=40,implemented case fragmented teaching method)and the control group(n=40,traditional teaching method).The training lasted for 2 months,and the medical history collection,medical record analysis,practical operation ability,theoretical assessment results,and the degree of satisfaction towards the training of the two groups of doctors were compared.Results:After 2 months of training,the theoretical knowledge and operational ability of the doctors in the two groups have improved to a certain extent,but the medical history collection,medical record analysis,practical operation ability,theoretical assessment results and satisfaction of the doctors in the experimental group were significantly better than those in the control group(P<0.05).Conclusion:The effect of the fragmented case teaching method in the standardized training of anesthesiology residents is significantly better than the traditional teaching mode.The abilities of doctors have significantly improved after the training.Hence,the fragmented case teaching method is worthy of promotion in clinical practice. 展开更多
关键词 Case fragmentation teaching Anesthesiology department Resident physician Standardized training Application
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Advantages and Disadvantages of Fragmented Learning and Recommendations 被引量:2
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作者 Jie ZHU Ping CHEN Wenjun JIA 《Asian Agricultural Research》 2019年第4期87-88,92,89,共4页
The development of information technology has changed people's learning methods. Fragmented learning,as an informal learning method,has become an important way to accept new knowledge and learn new technologies. T... The development of information technology has changed people's learning methods. Fragmented learning,as an informal learning method,has become an important way to accept new knowledge and learn new technologies. Through analyzing the connotation,characteristics,and advantages and disadvantages of fragmented learning,this paper came up with reasonable recommendations for fragmented learning. To truly become systematic and holistic knowledge,fragmented knowledge must be explored,understood,integrated and internalized. This paper is expected to play an important guiding role in building a lifelong learning society. 展开更多
关键词 fragmented LEARNING fragmented INFORMATION Advantages and disadvantages fragmented THINKING Feasible RECOMMENDATIONS
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Importance of microhabitat selection by birds for the early recruitment of endangered trees in a fragmented forest 被引量:1
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作者 Ning Li Zheng Wang +1 位作者 Yao Cai Lin Zhang 《Avian Research》 CSCD 2020年第4期446-451,共6页
Background:Remnant microhabitats are important for bird habitat selection and plant regeneration in the fragmented habitat.However,empirical information on the consequences of how microhabitat use by birds affects the... Background:Remnant microhabitats are important for bird habitat selection and plant regeneration in the fragmented habitat.However,empirical information on the consequences of how microhabitat use by birds affects the early recruitment of plants is lacking.Methods:In this study,we evaluated whether microhabitat selection by the Black Bulbul(Hypsipetes leucocephalus)(J.F.Gmelin,1789)impacts the early recruitment of the endangered tree species,the Chinese Yew(Taxus chinensis(Pilger)Rehd),in a fragmented forest over a 4-year period(2011–2012,2018–2019).Results:Our results showed the main factors affecting H.leucocephalus microhabitat selection were distance to the nearest T.chinensis mature tree,herb cover and density,leaf litter cover,and vegetation type.Moreover,the results of logistic regression also highlighted the importance of elevation,distance to light gap and roads,tree cover in bird microhabitat selection.Furthermore,the seed emergence rate in microhabitats used by birds did not differ from the natural forest,which was related to five factors of bird microhabitat.The Random Forest model showed that seedling emergence rate was increased with leaf litter cover and distance to fallen dead trees,but decreased in relation to herb cover,slope,and elevation.Conclusion:Our results highlight the importance of remnant microhabitats in fragmented forests for sustaining forest ecology and optimal management.The contribution of microhabitats used by birds to plant recruitment provides insights into how frugivore species contribute to plant regeneration,which should be incorporated in future conservation and management practices of fragmented forests. 展开更多
关键词 fragmented forest Hypsipetes leucocephalus Microhabitat use Seedling recruitment Taxus chinensis
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基于Fragmented Learning的中医药高效学习软件——“我药学”手机APP设计实现
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作者 孙方方 陈康 +1 位作者 高雪涵 罗晓牧 《现代商贸工业》 2016年第13期181-181,共1页
基于Fragmented Learning的中医药高效学习软件——"我药学"手机APP通过手机解锁记忆中医药知识,充分利用了学生日常生活中碎片化的时间,帮助记忆枯燥的学习内容,大大提高了学生的学习兴趣和学习效率,最终解决中医药知识记忆... 基于Fragmented Learning的中医药高效学习软件——"我药学"手机APP通过手机解锁记忆中医药知识,充分利用了学生日常生活中碎片化的时间,帮助记忆枯燥的学习内容,大大提高了学生的学习兴趣和学习效率,最终解决中医药知识记忆难的难题。 展开更多
关键词 fragmented LEARNING 手机APP 中医药学习
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Increased Prevalence of Severe Rheumatic Heart Disease Requiring Early Valve Replacement Surgery and Fragmented Germ Cells
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作者 Elizabeth Jeya Vardhini Samuel Ramesh   +3 位作者 K. B. Latha K. V. Lalitha Peter Prashanth Bosco Emmanuel 《International Journal of Clinical Medicine》 2014年第21期1392-1399,共8页
Background: Patients requiring valve replacement at a younger age, for rheumatic heart disease was apparently increasing after the new age practice of contraception. Methods: In 2012, data of patients referred to tert... Background: Patients requiring valve replacement at a younger age, for rheumatic heart disease was apparently increasing after the new age practice of contraception. Methods: In 2012, data of patients referred to tertiary care hospital from two cardiology screening camps conducted in the community, were analyzed for the severity of presentation of rheumatic heart disease and associated contraception status by dividing into the three age groups—20 - 35 years, 36 - 50 years, >51 years;~400 patients attended the camps;31 female and 2 male patients were referred to the tertiary care hospital for further evaluation and categorized treatment, including valve replacement surgeries;among the 33 referred patients, belonging to the three age groups, the data were analyzed for [if any] correlation of contraception status with severe rheumatic heart disease. 8 randomly chosen males, of the 3 age groups, from a different community, whose life partners had undergone sterilization, were assessed for their serum testosterone levels. Results: Among 20 - 35 years, 7 female patients with contraception required valve replacement surgeries [p 51 years, 3 female and 2 male patients without contraception received medical treatment only 展开更多
关键词 fragmented GERM Cells Reduced ENDOGENOUS ANDROGEN ESTROGEN Deranged Cell Metabolism Defaulted Genomic REPERTOIRE Enhanced FIBROSIS
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An Analysis of Fragmented Reading and Its Social Impact on College Students in the Era of New Media
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作者 Weiguo Xie 《Journal of Contemporary Educational Research》 2019年第3期33-37,共5页
In the era of new media,people’s lifestyle,education and the like are inseparable from the Internet.At the same time,due to the emergence of smart devices such as mobile phones and tablet computers,people’s reading ... In the era of new media,people’s lifestyle,education and the like are inseparable from the Internet.At the same time,due to the emergence of smart devices such as mobile phones and tablet computers,people’s reading habits have changed.Fragmented reading has become an important form of reading for college students.College students themselves have the strong ability to accept change,so fragmented reading has gradually become an important form of student learning.This paper mainly analyses fragmented reading by college students and its impact on society in the era of new media. 展开更多
关键词 ERA of new media COLLEGE STUDENTS fragmented READING SOCIAL impact
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Feasibility Investigation and Development Exploration on Popularizing the Method of English Fragmented Mobile Learning of Undergraduates
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作者 TANG Jia-hui LI Jing 《Journal of Literature and Art Studies》 2021年第7期504-508,共5页
This paper attempts to investigate the feasibility and learning effects of English fragmented learning via mobile devices.Questionnaires and interviews were employed to do the survey on 157 undergraduates from 24 univ... This paper attempts to investigate the feasibility and learning effects of English fragmented learning via mobile devices.Questionnaires and interviews were employed to do the survey on 157 undergraduates from 24 universities in China.The research findings reveal that English fragmented learning via mobile devices has some positive effects on the improvement of learners’knowledge and learning ability.In addition,there have been a certain number of useful learning resources and platforms with diversified features.The study has the implications that fragmented mobile learning is feasible and can be popularized in English learning. 展开更多
关键词 feasibility investigation UNDERGRADUATES English learning fragmented mobile learning
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Fragmented Core
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作者 Simon Allison 《ChinAfrica》 2014年第6期32-33,共2页
OCTOBER 25 is Central African Regional Integration Day. Few people know or observe this holiday because the citizens of Africa's poorest and most conflict-prone region have little to celebrate.
关键词 fragmented Core
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An assessment of population structure and regeneration status of Magnolia punduana Hk. f. & Th.(Magnoliaceae) in fragmented forests of northeast India 被引量:1
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作者 Viheno Iralu Ngakhainii Trune Pao Krishna Upadhaya 《Journal of Forestry Research》 SCIE CAS CSCD 2020年第3期937-943,共7页
The population structure and regeneration status of Magnolia punduana Hk. f. & Th., an endemic tree species of northeast India were investigated in fragmented forests in the Jarain Hills and in adjoining areas of ... The population structure and regeneration status of Magnolia punduana Hk. f. & Th., an endemic tree species of northeast India were investigated in fragmented forests in the Jarain Hills and in adjoining areas of Meghalaya state. The population structure was discontinuous in all the fragments with the absence of individuals in higher diameter classes. The number of individuals increased with the size of the fragment patches(p < 0.004). The density of mature trees(≥5 cm dbh) was high(24–30 individuals ha-1) in the largest fragment(>105 ha). The number of seedlings and saplings were also higher in the larger fragments. Human-related disturbances had a negative impact on the species population(p<0.002). Variation in the population density in different forest patches has been attributed to fragment size, site characteristics and ongoing human disturbances. The restricted distribution of the species coupled withexploitation and habitat destruction underlines the need for its conservation. 展开更多
关键词 Conservation DISTURBANCE FRAGMENTATION MAGNOLIA punduana RESTRICTED distribution
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Fragmented People in the Fragmented Country in Midnight's Children:Viewed from the Perspective of “Fragmentation”
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作者 郑秀芳 《海外英语》 2016年第15期185-189,共5页
In Midnight's Children,frequently seen are the words like"hole","segment","crack",and the damage and loss of bodily function such as amnesia,which is called a"phenomenon of fragm... In Midnight's Children,frequently seen are the words like"hole","segment","crack",and the damage and loss of bodily function such as amnesia,which is called a"phenomenon of fragmentation"in this paper.In terms of the phenomenon,the characters of three generations in Midnight's Children are analyzed.It is found that colonial culture exerts a long-lasting impact on its colonized people,under whose influence generations of colonized people find it hard to negotiate their dual cultural identities.This happened to India.Postcolonial Indians had fragmented identities.Furthermore,the phenomenon also reflects that India was a fragmented nation,whose nationals desired peace,unity,and prosperity. 展开更多
关键词 cultural identity Midnight’ s Children FRAGMENTATION HYBRIDITY
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Fragmented forest in tropical landscape——the case of the State of Selangor, Malaysia
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作者 Saiful Arif Abdullah 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 2003年第2期267-270,共4页
This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades. In this study, inventoried forest cover maps of Selangor in 19... This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades. In this study, inventoried forest cover maps of Selangor in 1971/1972, 1981/1982 and 1991/1992 produced by the Forestry Department of Peninsular Malaysia were digitized to examine the changes in area and number of fragmented forest. Results showed that in 1971/1972, 16 fragmented forests were identified in Selangor. All fragmented forests were identified as dipterocarp forest. A decade later the number of fragmented forests increased by approximately 44% (23). Of the 23 fragmented forests, two were peat swamp forests whereas the remaining were dipterocarp forests. In 1991/1992 the number of fragmented forests (12) was reduced by 47.8%. Two of the fragmented forests were identified as peat swamp forest, seven dipterocarp forest and the other three was mixed of dipterocarp forests and plantation forests. Fragmentation of both dipterocarp and peat swamp forests occurred profoundly during the period between 1971/1972 and 1981/1982, which consequently increased the number of fragmented forests compared with before the period of 1971/1972 where fragmentation happened only at dipterocarp forests. However, many fragmented forests vanished between the 1981/1982 and 1991/1992 periods. 展开更多
关键词 tropical rain forest tropical landscape FRAGMENTATION MALAYSIA
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Seed dispersal by Tana River mangabeys in fragmented gallery forests
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作者 Duncan M. Kimuyu Geoffrey M. Wahungu Dennis O. Otieno 《Open Journal of Ecology》 2012年第1期12-20,共9页
Data collected on a free ranging group of Tana River mangabeys (Cercocebus galeritus) indicates that this endangered primate species, which has previously been regarded as a seed predator, plays an important role in s... Data collected on a free ranging group of Tana River mangabeys (Cercocebus galeritus) indicates that this endangered primate species, which has previously been regarded as a seed predator, plays an important role in seed dispersal and do contribute to the regeneration of a highly fragmented gallery forest. We observed fruit handling behavior and the post-dispersal fate of seeds ingested by the mangabeys. The two main fruit handling behaviors observed, fruit swallowing and processing fruits in cheek pouches, positively contributed to seed disper- sal. Seed predation was not common during this study, apart from a few particular plant species such as Acacia robusta and Alangium salviifolium with non-fleshy fruits. We found a correlation between seed predation and fruit availability, respectively seasonal differential specific dispersal efficiency. The role of the mangabeys in dispersing seeds and facilitating forest regeneration is enhanced by their movement across forest patches through non-forested matrix, which contributes to the deposition of seeds and regeneration in these habitat gaps. 展开更多
关键词 Cercocebus Galeritus SEED Dispersal SEED PREDATION SEASONALITY Dispersal Efficiency Fragmentation Habitat GAPS Tana RIVER FORESTS
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Habitat Loss,Uneven Distribution of Resources and Fragmented Landscapes—A Resource Based Model of the Patch Size Effect
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作者 Pawel Adamski Adam Marcin Cmiel 《Applied Mathematics》 2014年第19期3206-3216,共11页
The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered... The problem of habitat fragmentation is recently an important issue in ecological research as well as in the practical approach of nature conservation. According to the most popular approaches, habitats are considered as the homogenous parts of the landscape. Also the metapopulation concept problem of the inert habitat heterogenity is considered quite seldom. These approaches have some weak points resulting from the assumption that the border between habitat patches and the metapopulation matrix is fairly sharp. This paper presents a resource-based concept of habitats, based on mathematical theory of point processes, which can be easily applied to analysing the problem of uneven distribution of resources. The basic assumption is that the random distribution of resources may be mathematically described as the realisation of a certain point process. According to our method, it is possible to calculate the expected quantities of available resources as well as the minimum area of habitat that includes the expected abundance of the resource. This approach may be very useful to understand some crucial phenomena in landscape ecology, such as the patch size effect and its connection to habitat loss and fragmentation. 展开更多
关键词 Patch Size Effect Allee Effect Habitat Loss Habitat Fragmentation Poisson Process Process Intensity Critical Patch Size
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Short-term Prognosis of Fragmented QRS Complex in Patients with Non-ST Elevated Acute Myocardial Infarction 被引量:14
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作者 Min Li Xiao Wang +4 位作者 Shu-Hua Mi Zhe Chi Qing Chen Xin Zhao Shao-Ping Nie 《Chinese Medical Journal》 SCIE CAS CSCD 2016年第5期518-522,共5页
Background:There remains significant debate as to the relationship between fragmented QRS (fQRS) complexes on electrocardiogram (ECG) and acute myocardial infarction (AMI).Few studies have reported on this rela... Background:There remains significant debate as to the relationship between fragmented QRS (fQRS) complexes on electrocardiogram (ECG) and acute myocardial infarction (AMI).Few studies have reported on this relationship in non-ST elevated AMI (NSTEMI),and thus,we attempt to assess this relationship and its potential short-term prognostic value.Methods:This was a single-center,observational,retrospective cohort study.A total of 513 consecutive patients (399 men,114 women) with NSTEMI within 24 h who underwent coronary angiography at our department,between January 1,2014,and December 31,2014.Patients were divided into 2 groups according to the presence or absence of fQRS complex on the admission ECG.fQRS complexes were defined as the existence of an additional R' or crochetage wave,notching in the nadir of the S wave,RS fragmentation,or QS complexes on 2 contiguous leads.All patients were followed up for 6 months,and all major adverse cardiac events (MACE) were recorded.Results:In this study,there were 285 patients with fQRS ECG in the 513 patients with NSTEMI.The number of patients with 0-2 coronary arteries narrowed by ≥50% in fQRS group were less while patients with 3 narrowed arteries were more than in the non-fQRS group (P =0.042).There were fewer Killip Class Ⅰ patients in the fQRS group (P =0.019),while Killip Class Ⅱ,Ⅲ,and Ⅳ patients were more in the fQRS group than in the non-fQRS group (P =0.019).Left ventricular ejection fraction levels were significantly lower in the fQRS group (P =0.021).Baseline total cholesterol,low-density lipoprotein,creatinine,creatine kinase,homocysteine,high-sensitivity C-reactive protein (CRP),and red blood cells distribution width levels were significantly higher in the fQRS group.Total MACE (MACE,P =0.028),revascularization (P =0.005),and recurrent angina (P =0.005) were also significantly greater in the fQRS group.On final logistic regression analysis,after adjusting for baseline variables,the following variables were independent predictors of fQRS:Coronary artery narrowing (P =0.035),Killip classification (P =0.026),and total cholesterol (P =0.002).The following variables were found to be independent predictors of preoperative MACE:Hemoglobin (P =0.000),gender (P =0.026),fQRS (P =0.016),and time from myocardial infarction to balloon or coronary artery bypasses grafting (P =0.013).Conclusions:The fQRS complexes are commonly present in NSTEMI and the fQRS complexes are an independent predictor of MACE in NSTEMI patients.The number of narrowed coronary arteries,Killip classification,and total cholesterol are all independent predictors of the fQRS complexes. 展开更多
关键词 fragmented QRS Complexes Major Adverse Cardiac Events Non-ST Elevated Acute Myocardial Infarction
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Presence of Fragmented QRS Complexes in Patients with Obstructive Sleep Apnea Syndrome 被引量:5
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作者 Muhammet Rasit Sayin Murat Altuntas +6 位作者 Ziyaeddin Aktop Ibrahim I Oz Nesimi Yavuz Ibrahim Akpinar Erol Sagatli Turgut Karabag Mustafa Aydin 《Chinese Medical Journal》 SCIE CAS CSCD 2015年第16期2141-2146,共6页
Background:Obstructive sleep apnea syndrome (OSAS) is a disease with increasing prevalence,which is mainly characterized by increased cardiopulmonary mortality and morbidity.It is well-known that OSAS patients have... Background:Obstructive sleep apnea syndrome (OSAS) is a disease with increasing prevalence,which is mainly characterized by increased cardiopulmonary mortality and morbidity.It is well-known that OSAS patients have increased prevalence of cardiovascular diseases including coronary heart disease,heart failure,and arrhythmias.The aim of this study was to evaluate the presence of prolonged and fragmented QRS complexes,which have previously been associated with cardiovascular mortality,in OSAS patients.Methods:Our study included 51 patients (mean age 41.6 ± 10.1 years) who were recently diagnosed with OSAS (apnea-hypopnea index [AHI] ≥5 events/h) and never received therapy.The control group consisted of 34 volunteers (mean age 43.1 ± 11.6 years) in whom OSAS was excluded (AHI 〈5 events/h).The longest QRS complexes was measured in the 12-lead electrocardiogram (ECG) and the presence of fragmentation in QRS complexes was investigated.Results:Fragmented QRS frequency was significantly higher in patients with OSAS (n =31 [61%] vs.n =12 [35%],P =0.021).QRS and QTc durations were also significantly longer in OSAS patients than controls (99.8 ± 13.9 ms vs.84.7 ± 14.3 ms,P 〈 0.001;411.4 ± 26.9 ms vs.390.1 ± 32.2 ms,P =0.001,respectively).Analysis of the patient and controls groups combined revealed a weak-moderate correlation between AHI and QRS duration (r =0.292,P =0.070).OSAS group had no correlation between AHI and QRS duration (r =-0.231,P =0.203).Conclusions:In our study fragmented QRS frequency and QRS duration were found to increase in OSAS patients.Both parameters are related with increased cardiovascular mortality.Considering the prognostic importance of ECG parameters,it may be reasonable to recommend more detailed evaluation of OSAS patients with fragmented or prolonged QRS complexes with respect to presence of cardiovascular diseases. 展开更多
关键词 ELECTROCARDIOGRAM fragmented QRS Obstructive Sleep Apnea QRS Duration QT Duration
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Disaster victim identification operations with fragmented,burnt,or commingled remains:experience-based recommendations 被引量:3
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作者 Hans H.de Boer Julie Roberts +2 位作者 Tania Delabarde Amy Z.Mundorff Soren Blau 《Forensic Sciences Research》 CSCD 2020年第3期191-201,共11页
Human-made and natural disasters can result in severely fragmented,compromised,and commingled human remains.The related disaster victim identification(DVI)operations are invariably challenging,with the state of the re... Human-made and natural disasters can result in severely fragmented,compromised,and commingled human remains.The related disaster victim identification(DVI)operations are invariably challenging,with the state of the remains potentially precluding some identifications.Practitioners involved in these DVI operations will routinely face logistical,practical,and ethical challenges.This review provides information and guidance derived from firsthand experiences to individuals tasked with managing DVI operations with fragmented human remains.We outline several key issues that should be addressed during disaster preparedness planning and at the outset of an operation,when incident-specific strategies are developed.Specific challenges during recovery and examination of fragmented remains are addressed,highlighting the importance of experienced specialists at the scene and in the mortuary.DNA sample selection and sampling techniques are reviewed,as well as downstream effects of commingling and contamination,which can complicate reconciliation and emphasise the need for rigorous quality control.We also touch on issues that may arise during communication with families.While recommendations are provided,they are not intended as proscriptive policy but rather as an addition to the general recommendations given in the International Criminal Police Organization(INTERPOL)DVI Guide,to inform preparative discussions between government officials,judiciary,police,and forensic specialists. 展开更多
关键词 Forensic sciences forensic anthropology DVI fragmented human remains burnt commingled DNA
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Fragrep: An Efficient Search Tool for Fragmented Patterns in Genomic Sequences 被引量:1
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作者 Axel Mosig Katrin Sameith Peter Stadler 《Genomics, Proteomics & Bioinformatics》 SCIE CAS CSCD 2006年第1期56-60,共5页
Many classes of non-coding RNAs (ncRNAs; including Y RNAs, vault RNAs, RNase P RNAs, and MRP RNAs, as well as a novel class recently discovered in Dictyostelium discoideum) can be characterized by a pattern of short... Many classes of non-coding RNAs (ncRNAs; including Y RNAs, vault RNAs, RNase P RNAs, and MRP RNAs, as well as a novel class recently discovered in Dictyostelium discoideum) can be characterized by a pattern of short but well-conserved sequence elements that are separated by poorly conserved regions of sometimes highly variable lengths. Local alignment algorithms such as BLAST are therefore ill-suited for the discovery of new homologs of such ncRNAs in genomic sequences. The Fragrep tool instead implements an efficient algorithm for detecting the pattern fragments that occur in a given order. For each pattern fragment, the mismatch tolerance and bounds on the length of the intervening sequences can be specified separately. Furthermore, matches can be ranked by a statistically well-motivated scoring scheme. 展开更多
关键词 Fragrep non-coding RNA detection fragmented pattern Dictyostelium discoideum
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Effects of landscape fragmentation of plantation forests on carbon storage in the Loess Plateau,China
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作者 LEI Hangyu DUAN Dantong +3 位作者 CHEN Yi GUO Huifeng LI Jiangtao LI Xiang 《Journal of Arid Land》 SCIE CSCD 2024年第2期266-281,共16页
Tree plantation and forest restoration are the major strategies for enhancing terrestrial carbon sequestration and mitigating climate change.The Grain for Green Project in China has positively impacted global carbon s... Tree plantation and forest restoration are the major strategies for enhancing terrestrial carbon sequestration and mitigating climate change.The Grain for Green Project in China has positively impacted global carbon sequestration and the trend towards fragmentation of plantation forests.Limited studies have been conducted on changes in plantation biomass and stand structure caused by fragmentation,and the effect of fragmentation on the carbon storage of plantation forests remains unclear.This study evaluated the differences between carbon storage and stand structure in black locust forests in fragmented and continuous landscape in the Ansai District,China and discussed the effects of ecological significance of four landscape indices on carbon storage and tree density.We used structural equation modelling to explore the direct and indirect effects of fragmentation,edge,abiotic factors,and stand structure on above-ground carbon storage.Diameter at breast height(DBH)in fragmented forests was 53.3%thicker,tree density was 40.9%lower,and carbon storage was 49.8%higher than those in continuous forests;for all given DBH>10 cm,the trees in fragmented forests were shorter than those in continuous forests.The patch area had a negative impact on carbon storage,i.e.,the higher the degree of fragmentation,the lower the density of the tree;and fragmentation and distance to edge(DTE)directly increased canopy coverage.However,canopy coverage directly decreased carbon storage,and fragmentation directly increased carbon storage and tree density.In non-commercial forests,fragmentation reduces the carbon storage potential of plantation,and the influence of patch area,edge,and patchy connection on plantation should be considered when follow-up trees are planted and for the plantation management.Thus,expanding the area of plantation patches,repairing the edges of complex-shaped patches,enhancing the connectivity of similar patches,and applying nutrients to plantation forests at regular intervals are recommended in fragmented areas of the Loess Plateau. 展开更多
关键词 landscape fragmentation PLANTATION carbon storage tree allometry tree density structural equation modelling
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Progressive fragmentation of granular assemblies within rockslides: Insights from discrete-continuous numerical modeling
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作者 JIANG Hui ZHOU Yuande +2 位作者 WANG Jinting DU Xiuli HUANG Hailong 《Journal of Mountain Science》 SCIE CSCD 2024年第4期1174-1189,共16页
Rock fragmentation plays a critical role in rock avalanches,yet conventional approaches such as classical granular flow models or the bonded particle model have limitations in accurately characterizing the progressive... Rock fragmentation plays a critical role in rock avalanches,yet conventional approaches such as classical granular flow models or the bonded particle model have limitations in accurately characterizing the progressive disintegration and kinematics of multi-deformable rock blocks during rockslides.The present study proposes a discrete-continuous numerical model,based on a cohesive zone model,to explicitly incorporate the progressive fragmentation and intricate interparticle interactions inherent in rockslides.Breakable rock granular assemblies are released along an inclined plane and flow onto a horizontal plane.The numerical scenarios are established to incorporate variations in slope angle,initial height,friction coefficient,and particle number.The evolutions of fragmentation,kinematic,runout and depositional characteristics are quantitatively analyzed and compared with experimental and field data.A positive linear relationship between the equivalent friction coefficient and the apparent friction coefficient is identified.In general,the granular mass predominantly exhibits characteristics of a dense granular flow,with the Savage number exhibiting a decreasing trend as the volume of mass increases.The process of particle breakage gradually occurs in a bottom-up manner,leading to a significant increase in the angular velocities of the rock blocks with increasing depth.The simulation results reproduce the field observations of inverse grading and source stratigraphy preservation in the deposit.We propose a disintegration index that incorporates factors such as drop height,rock mass volume,and rock strength.Our findings demonstrate a consistent linear relationship between this index and the fragmentation degree in all tested scenarios. 展开更多
关键词 Rock fragmentation ROCKSLIDE Numerical modelling Discrete-continuous modelling RUNOUT Cohesive zone model
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Numerical and experimental investigation on hydraulic-electric rock fragmentation of heterogeneous granite
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作者 Xiaohua Zhu Ling He +3 位作者 Weiji Liu Yunxu Luo Youjian Zhang Wuji Tang 《International Journal of Mining Science and Technology》 SCIE EI CAS CSCD 2024年第1期15-29,共15页
Hydraulic-electric rock fragmentation(HERF)plays a significant role in improving the efficiency of high voltage pulse rock breaking.However,the underlying mechanism of HERF remains unclear.In this study,considering th... Hydraulic-electric rock fragmentation(HERF)plays a significant role in improving the efficiency of high voltage pulse rock breaking.However,the underlying mechanism of HERF remains unclear.In this study,considering the heterogeneity of the rock,microscopic thermodynamic properties,and shockwave time domain waveforms,based on the shockwave model,digital imaging technology and the discrete element method,the cyclic loading numerical simulations of HERF is achieved by coupling electrical,thermal,and solid mechanics under different formation temperatures,confining pressure,initial peak voltage,electrode bit diameter,and loading times.Meanwhile,the HERF discharge system is conducive to the laboratory experiments with various electrical parameters and the resulting broken pits are numerically reconstructed to obtain the geometric parameters.The results show that,the completely broken area consists of powdery rock debris.In the pre-broken zone,the mineral cementation of the rock determines the transition of type CⅠcracks to type CⅡand type CⅢcracks.Furthermore,the peak pressure of the shockwave increased with initial peak voltage but decreased with electrode bit diameter,while the wave front time reduced.Moreover,increasing well depth,formation temperature and confining pressure augment and inhibit HERF,but once confining pressure surpassed the threshold of 60 MPa for 152.40,215.90,and 228.60 mm electrode bits,and 40 MPa for 309.88 mm electrode bits,HERF is promoted.Additionally,for the same kind of rock,the volume and width of the broken pit increase with higher initial peak voltage and rock fissures will promote HERF.Eventually,the electrode drill bit with a 215.90 mm diameter is more suitable for drilling pink granite.This research contributes to a better microscopic understanding of HERF and provides valuable insights for electrode bit selection,as well as the optimization of circuit parameters for HERF technology. 展开更多
关键词 Hydraulic-electric rock fragmentation SHOCKWAVE Thermodynamics MICROCRACKS Weak Linear Parallel Bond Model
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