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Racial differences in the anatomical distribution of colorectal cancer:a study of differences between American and Chinese patients 被引量:30
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作者 San-HuaQing Kai-YunRao +1 位作者 Hui-YongJiang StevenD.Wexner 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第4期721-725,共5页
AIM: To compare the racial differences of anatomical distribution of colorectal cancer (CRC) and determine the association of age, gender and time with anatomical distribution between patients from America (white) and... AIM: To compare the racial differences of anatomical distribution of colorectal cancer (CRC) and determine the association of age, gender and time with anatomical distribution between patients from America (white) and China (oriental).METHODS: Data was collected from 690 consecutive patients in Cleveland Clinic Florida, U.S.A. and 870consecutive patients in Nan Fang Hospital affiliated to the First Military Medical University, China over the past 11years from 1990 to 2000. All patients had colorectal adenocarcinoma diagnosed by histology and underwent surgery.RESULTS: The anatomical subsite distribution of tumor,age and gender were significantly different between white and oriental patients. Lesions in the proximal colon (P<0.001) were found in 36.3 % of white vs 26.0 % of oriental patients and cancers located in the distal colon and rectum in 63.7 % of white and 74 % of oriental patients (P<0.001). There was a trend towards the redistribution from distal colon and rectum to proximal colon in white males over time, especially in older patients (>80 years).No significant change of anatomical distribution occurred in white women and Oriental patients. The mean age at diagnosis was 69.0 years in white patients and 48.3 years in Oriental patients (P<0.001).CONCLUSION: This is the first study comparing the anatomical distribution of colorectal cancers in whites and Chinese patients. White Americans have a higher risk of proximal CRC and this risk increased with time. The proportion of white males with CRC also increased with time.Chinese patients were more likely to have distal CRC and developed the disease at a significantly earlier age than white patients. These findings have enhanced our understanding of the disease process of colorectal cancer in these two races. 展开更多
关键词 Asian Continental Ancestry Group European Continental Ancestry Group ADENOCARCINOMA ADULT age distribution aged aged 80 and over China Colonic Neoplasms Colorectal Neoplasms Comparative Study Female Humans Male Middle aged Rectal Neoplasms Retrospective Studies United States
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Age structure and static life tables of the endangered Juniperus phoenicea L. in North Sinai Mountains, Egypt:implication for conservation 被引量:5
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作者 Emad A.FARAHAT 《Journal of Mountain Science》 SCIE CSCD 2020年第9期2170-2178,共9页
Studying the population ecology of endangered plants provides important baseline information for its monitoring and conservation.Juniperus phoenicea L.is an endangered species in arid ecosystems in Africa and the Midd... Studying the population ecology of endangered plants provides important baseline information for its monitoring and conservation.Juniperus phoenicea L.is an endangered species in arid ecosystems in Africa and the Middle East.The static life tables,survival curve and age structure of J.phoenicea populations from two mountains in North Sinai,Egypt(Gabal(G.)El-Halal and G.El-Maghara)were investigated.In each mountain,fifteen plots were selected,and field measurements such as stand density,tree height,and crown diameter were conducted.Moreover,44 trees were cored and crossdated according to standard dendrochronological procedures.The results showed that the tree ages ranged from 50 to 262 years at G.El-Halal and 96 to431 years at G.El-Maghara.Mature J.phoenicea individuals dominated the study area,with only a few individuals being younger than 100 years.Moreover,seedling recruitment was extremely limited.Since the studied J.phoenicea populations showed high mortality rates among both old and young individuals,there is an imminent need for establishing a conservation program to prevent its extinction in the future.Therefore,management and conservation efforts should be made to minimize human disturbance and protect the relic habitats of this endangered species at its southern distribution limits in Africa. 展开更多
关键词 Juniperus phoenicea age distribution Life history MORTALITY Endangered plant SINAI
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Influence of Superplasticizers on Early Age Drying Shrinkage of Cement Paste with the Same Consistency 被引量:3
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作者 赖俊英 ZHANG Lifeng +2 位作者 钱晓倩 SHEN Chong ZHANG Jinjian 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2014年第6期1201-1207,共7页
The influence of superplasticizer(SP) on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for ... The influence of superplasticizer(SP) on the early age drying shrinkage of cement paste with the same consistency was investigated. To conduct the test, which lasted for 72 hours, three paste mixtures were used for comparison. The 72 hours early age drying shrinkage staring from the initial setting time was measured by a clock gauge. The pore size distribution was measured by Mercury Intrusion Method. The surface tension of capillary simulation liquid and mass loss of paste were also measured. The experimental results showed that the addition of SP increased the early drying shrinkage greatly. The ratios of water evaporation and the total free water in mixtures added with SPs showed great differences. SPs fined the capillary pores of paste, and the volume of pore with diameter within 50 nm was well consistent with shrinkage rate. The addition of SPs did not raise the capillary liquid surface tension. It showed that with the volume of pore with diameter within 50 nm and the ratio of water evaporation and the total free water a tolerable shrinkage result of paste added with SP could be predicted, and the elastic modulus could have an influence on the early shrinkage. These results have never been proposed before. 展开更多
关键词 superplasticizer early age drying shrinkage paste water evaporation pore size distribution
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Striking elevation in incidence and prevalence of inflammatory bowel disease in a province of western Hungary between 1977-2001 被引量:17
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作者 Laszlo Lakatos Gabor Mester +4 位作者 Zsuzsanna Erdelyi Mihaly Balogh Istvan Szipocs Gyorgy Kamaras Peter Laszlo Lakatos 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第3期404-409,共6页
AIM:An investigation into inflammatory bowel disease and colorectal cancer in Veszprem Province was conducted from 1977 to 2001.METHODS: Both hospital and outpatient records were collected and reviewed comprehensively... AIM:An investigation into inflammatory bowel disease and colorectal cancer in Veszprem Province was conducted from 1977 to 2001.METHODS: Both hospital and outpatient records were collected and reviewed comprehensively. The majority of patients were followed up regularly.RESULTS:The population of the province was decreased from 386000 to 376000 during the period. Five hundred sixty new cases of ulcerative colitis (UC), 212 of Crohn's disease (CD), and 40 of indeterminate colitis (IC) were diagnosed. The incidence rates increased from 1.66 to 11.01 cases per 100 000 persons for UC, from 0.41 to 4.68 for CD and from 0.26 to 0.74 for IC. The prevalence rate at the end of 2001 was 142.6 for UC and 52.9 cases per 100 000 persons for CD. The peak onset age in UC patients was between 30 and 40 years, in CD between 20 and 30 years. A family history of IBD was present in 3.4% in UC and 9.9% in CD patients.Smoking increased the risk for CD (OR=1.94) while it decreased the risk for UC (OR=0.25). Twelve colorectal carcinomas were observed in this cohort, the cumulative colorectal cancer risk after 10 years in UC was 2%, after 20 years 8.8%, after 30 years 13.3%.CONCLUSION:The incidence and prevalence rates of IBD have increased steadily in Veszprem Province, now equivalent to that in Western European countries. Rapid increase in incidence rates supports a probable role for environmental factors. The rate of colorectal cancers in IBD is similar to that observed in Western countries. 展开更多
关键词 ADULT age distribution Colorectal Neoplasms FEMALE Health Surveys Humans Hungary INCIDENCE Inflammatory Bowel Diseases MALE Middle aged PREVALENCE
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Association of extraintestinal manifestations of inflammatory bowel disease in a province of western Hungary with disease phenotype:Results of a 25-year follow-up study 被引量:25
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作者 Laszlo Lakatos Tunde Pandur +4 位作者 Gyula David Zsuzsanna Balogh Pal Kuronya Arpad Tollas Peter Laszlo Lakatos 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第10期2300-2307,共8页
AIM:IBD is a systemic disease associated with a large number of extraintestinal manifestations (EIMs).Our aim was to determine the prevalence of EIMs in a large IBD cohort in Veszprem Province in a 25-year follow-up s... AIM:IBD is a systemic disease associated with a large number of extraintestinal manifestations (EIMs).Our aim was to determine the prevalence of EIMs in a large IBD cohort in Veszprem Province in a 25-year follow-up study. METHODS:Eight hundred and seventy-three IBD patients were enrolled (ulcerative colitis/UC/:619,m/f:317/302, mean age at presentation:38.3 years,average disease duration:11.2 years;Crohn's disease/CD/:254,m/f:125/129, mean age at presentation:32.5 years,average disease duration:9.2 years).Intestinal,extraintestinal signs and laboratory tests were monitored regularly.Any alteration suggesting an EIMs was investigated by a specialist. RESULTS:A total of 21.3% of patients with IBD had EIM (UC:15.0%,CD:36.6%).Age at presentation did not affect the likelihood of EIM.Prevalence of EIMs was higher in women and in CD,ocular complications and primary sclerosing cholangitis (PSC) were more frequent in UC.In UC there was an increased tendency of EIM in patients with a more extensive disease.Joint complications were more frequent in CD (22.4% vsUC 10.2%,P<0.01).In UC positive family history increased the risk of joint complications (OR:3.63).In CD the frequency of type-1 peripheral arthritis was increased in patients with penetrating disease (P=0.028).PSC was present in 1.6% in UC and 0.8% in CD.Dermatological complications were present in 3.8% in UC and 10.2% in CD,the rate of ocular complications was around 3% in both diseases.Rare complications were glomerulonephritis,autoimmune hemolytic anaemia and celiac disease. CONCLUSION:Prevalence of EIM in Hungarian IBD patients is in concordance with data from Western countries.The high number of EIM supports a role for complex follow-up in these patients. 展开更多
关键词 ADOLESCENT Adult age distribution aged aged 80 and over Anemia Iron-Deficiency Bile Duct Diseases Child Colitis Ulcerative Crohn Disease Eye Diseases Female Follow-Up Studies Humans Hungary Joint Diseases Liver Diseases Male Middle aged PHENOTYPE Prevalence
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Healthy ranges of serum alanine aminotransferase levels in Iranian blood donors 被引量:6
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作者 Mehdi Mohamadnejad Akram Pourshams +6 位作者 Reza Malekzadeh Ashraf Mohamadkhani Afsaneh Rajabiani Ali Ali Asgari Seyed Meysam Alimohamadi Hadi Razjooyan Mansooreh Mamar-Abadi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2003年第10期2322-2324,共3页
AIM: The healthy ranges for serum alanine aminotransferase(ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated ... AIM: The healthy ranges for serum alanine aminotransferase(ALT) levels are less well studied. The aim of this study was to define the upper limit of normal (ULN) for serum ALT levels, and to assess factors associated with serum ALT activity in apparently healthy blood donors. METHODS: A total of 1 939 blood donors were included.ALT measurements were performed for all cases using the same laboratory method. Healthy ranges for ALT levels werecomputed from the population at the lowest risk for liver disease. Univariate and multivariate analyses were performed to evaluate associations between clinical factors and ALT levels.RESULTS: Serum ALT activity was independently associated with body mass index (BMI) and male gender, but not associated with age. Association of ALT with BMI was more prominent in males than in females. Upper limit of normal for non-overweight women (BMI of less than 25) was 34 U/L,and for non-overweight men was 40 U/L.CONCLUSION: Serum ALT is strongly associated with sex and BMI. The normal range of ALT should be defined for male and female separately. 展开更多
关键词 ADOLESCENT ADULT age distribution aged Alanine Transaminase Blood Donors Body Mass Index Chemistry Clinical numerical data CHILD Female Humans Iran Logistic Models Male Middle aged Reference Values Sex distribution
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A comparative study on serologic profiles of virus hepatitis B 被引量:6
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作者 BoYOUl Cho Moran Ki Hung Bae Park 《World Journal of Gastroenterology》 SCIE CAS CSCD 2001年第1期107-110,共4页
INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarci... INTRODUCTIONHepatitis B viral infection, one of the most-prevalent liver disorders in China and Korea, is aserious infectious disease as it has the potential ofprogressing into liver cirrhosis and primary hepaticcarcinoma. China and Korea both belong to high-risk endemic regions of viral hepatitis[1]. TheHBsAg positive rates in China ranged from 6.9% -17.9% by age, race and test methods[2-5]. 展开更多
关键词 Adult age distribution Antibodies Viral China Comparative Study Enzyme-Linked Immunosorbent Assay Ethnic Groups Female Hepatitis B Hepatitis B Surface Antigens Hepatitis B virus Humans Korea Male Middle aged Research Support Non-U.S. Gov't Seroepidemiologic Studies Sex distribution
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Perioperative chemotherapy for advanced gastric cancer - results from a tertiary-care hospital in Germany 被引量:5
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作者 Katrin Bauer Giulia Manzini +1 位作者 Doris Henne-Bruns Peter Buechler 《World Journal of Gastrointestinal Oncology》 SCIE CAS 2020年第5期559-568,共10页
BACKGROUND Neoadjuvant/perioperative chemotherapy is the recommended treatment for advanced stages of gastric cancer(>T2,N+)before tumour resection in many European guidelines.However,there is no consensus as to wh... BACKGROUND Neoadjuvant/perioperative chemotherapy is the recommended treatment for advanced stages of gastric cancer(>T2,N+)before tumour resection in many European guidelines.However,there is no consensus as to whether perioperative chemotherapy is as effective in distal as in proximal tumours,in addition to a relevant uncertainty concerning appropriate treatment modalities for elderly patients.AIM To investigate the role of perioperative chemotherapy in advanced gastric cancer in patients from a German tertiary clinic with respect to efficacy,localisation,and age.METHODS We performed a retrospective analysis of 158 patients from our clinic with adenocarcinoma of the stomach or the gastroesophageal junction who underwent resection between 2008 and 2016.The data were evaluated particularly in relation to patient age,tumour site,and perioperative therapy.RESULTS Administration of perioperative chemotherapy did not lead to a significant survival advantage in our study population.The 5-year survival rates were 40%for patients who received perioperative chemotherapy and 29%for the group without perioperative chemotherapy(P=0.125).Our patients were on average distinctly older than patients in most of the published randomised controlled trials.Patients elder than 75 years received perioperative chemotherapy far less frequently.Patients with a proximal tumour received perioperative chemotherapy much more often.CONCLUSION This analysis reconfirms our previous data concerning the effectiveness of perioperative chemotherapy for advanced gastric cancer.There is reasonable doubt that the quality of the existing randomized controlled trials is sufficient to generally justify perioperative chemotherapy in patients with advanced gastric cancer independent of tumour localization or age. 展开更多
关键词 Gastric cancer PERIOPERATIVE Chemotherapy Tumour localisation age distribution Validity
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Gastric malignancies in Northern Jordan with special emphasis on descriptive epidemiology 被引量:4
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作者 Kamal E.Bani-Hani Rami J.Yaghan +4 位作者 Hussein A.Heis Nawaf J.Shatnawi Ismail I.Matalka Amjad M.Bani-Hani Kamal A.Gharaibeh 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第15期2174-2178,共5页
AIM:To study the epidemiology of gastric malignancies in Jordan as a model for Middle East countries where such data is scarce. METHODS:Pertinent epidemiological and clinicopathological data for 201 patients with gast... AIM:To study the epidemiology of gastric malignancies in Jordan as a model for Middle East countries where such data is scarce. METHODS:Pertinent epidemiological and clinicopathological data for 201 patients with gastric malignancy in north of Jordan between 1991 and 2001 were analyzed. RESULTS:Male:female ratio was 1.8:1.The mean age was 61.2 years,and 8.5% of the patients were younger than 40 years of age.The overall age-adjusted incidence was 5.82/100 000 population/year.The age specific incidence for males raised from 1.48 in those aged 30-39 years to 72.4 in those aged 70-79 years.Adenocarcinomas, gastric lymphomas,malignant stromal tumors,and carcinoids were found in 87.5%,8%,2.5%,and 2% respectively.There was an average of 10.1-month delay between the initial symptoms and the diagnosis.Only 82 patients underwent“curative”gastrectomy.Among adenocarcinoma groups,Lauren intestinal type was the commonest(72.2%)and the distal third was the most common localization(48.9%).The mean follow up for patients with gastric adenocarcinoma was 25.1 mo(range 1-132mo).The 5-year survival rates for stages Ⅰ(n=15), Ⅱ(n=41),Ⅲ(n=59),and Ⅳ(n=53) were 67.3%,41.3%, 5.7%,and 0% respectively(P=0.0001).The overall 5 year survival was 21.1%. CONCLUSION:Despite low inddence,some epidemiological features of gastric cancer in Jordan mimic those of high- risk areas.Patients are detected and treated after a relatively long delay.No justification in favor of a possible gastric cancer screening effort in Jordan is supported by our study;rather,the need of an earlier diagnosis and subsequent better care. 展开更多
关键词 Adolescent Adult age distribution aged aged 80 and over CHILD Child Preschool Female GASTRECTOMY numerical data Humans Incidence INFANT Infant Newborn JORDAN Male Middle aged Sex distribution Stomach Neoplasms Survival Analysis
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An extended assessment of bowel habits in a general population
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作者 Gabrio Bassotti Massimo Bellini +5 位作者 Filippo Pucciani Renato Bocchini Antonio Bove Pietro Alduini Edda Battaglia Paolo Bruzzi 《World Journal of Gastroenterology》 SCIE CAS CSCD 2004年第5期713-716,共4页
AIM:Bowel habits are difficult to study, and most data on defecatory behaviour in the general population have been obtained on the basis of recalled interview. The objective assessment of this physiological function a... AIM:Bowel habits are difficult to study, and most data on defecatory behaviour in the general population have been obtained on the basis of recalled interview. The objective assessment of this physiological function and its pathological aspects continues to pose a difficult challenge. The aim of this prospective study was to objectively assess the bowel habits and related aspects in a large sample drawn from thegeneral population.METHODS: Over a two-month period 488 subjects were prospectively recruited from the general population and asked to compile a daily diary on their bowel habits and associated signs and symptoms (the latter according to Rome Ⅱ criteria). A total of 298 (61%) participants returned a correctly compiled record, so that data for more than 8000 patient-days were available for statistical analysis.RESULTS:The average defecatory frequency was once per day (range of 0.25-3.25) and was similar between males and females.However, higher frequencies of straining at stool (P=0.001), a feeling of incomplete emptying and/or difficult evacuation (P=0.0001), and manual manoeuvres to facilitate defecation (P=0.046) were reported by females as compared to males.CONCLUSION:This study represents one of the first attempts to objectively and prospectively assess bowel habits in a sample of the general population over a relatively long period of time. The variables we analyzed are coherent with the criteria commonly used for the clinical assessment of functional constipation, and can provide a useful adjunt for a better evaluation of constipated patients. 展开更多
关键词 DEFECATION Health Behavior ADULT age distribution CONSTIPATION Female Humans Male Middle aged Prospective Studies Sex distribution
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Science Letters:Two ancient rounds of polyploidy in rice genome
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作者 张扬 徐国华 +1 位作者 郭兴益 樊龙江 《Journal of Zhejiang University-Science B(Biomedicine & Biotechnology)》 SCIE CAS CSCD 2005年第2期87-90,共4页
An ancient genome duplication (PPP1) that predates divergence of the cereals has recently been recognized. We report here another potentially older large-scale duplication (PPP2) event that predates monocot-dicot dive... An ancient genome duplication (PPP1) that predates divergence of the cereals has recently been recognized. We report here another potentially older large-scale duplication (PPP2) event that predates monocot-dicot divergence in the genome of rice (Oryza sativa L.), as inferred from the age distribution of pairs of duplicate genes based on recent genome data for rice. Our results suggest that paleopolyploidy was widespread and played an important role in the evolution of rice. 展开更多
关键词 Oryza sativa POLYPLOIDY Genome evolution age distribution of duplicate genes Monocot-dicot divergence
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Unraveling one billion years of geological evolution of the southeastern Amazonia Craton from detrital zircon analyses
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作者 Camille Rossignol Paul Yves Jean Antonio +8 位作者 Francesco Narduzzi Eric Siciliano Rego Lívia Teixeira Romário Almeida de Souza Janaína N.Ávila Marco A.L.Silva Cristiano Lana Ricardo I.F.Trindade Pascal Philippot 《Geoscience Frontiers》 SCIE CAS CSCD 2022年第5期129-152,共24页
Despite representing one of the largest cratons on Earth,the early geological evolution of the Amazonia Craton remains poorly known due to relatively poor exposure and because younger metamorphic and tectonic events h... Despite representing one of the largest cratons on Earth,the early geological evolution of the Amazonia Craton remains poorly known due to relatively poor exposure and because younger metamorphic and tectonic events have obscured initial information.In this study,we investigated the sedimentary archives of the Carajás Basin to unravel the early geological evolution of the southeastern Amazonia Craton.The Carajás Basin contains sedimentary rocks that were deposited throughout a long period spanning more than one billion years from the Mesoarchean to the Paleoproterozoic.The oldest archives preserved in this basin consist of a few ca.3.6 Ga detrital zircon grains showing that the geological roots of the Amazonia Craton were already formed by the Eoarchean.During the Paleoarchean or the early Mesoarchean(<3.1 Ga),the Carajás Basin was large and rigid enough to sustain the formation and preservation of the Rio Novo Group greenstone belt.Later,during the Neoarchean,at ca.2.7 Ga,the southeastern Amazonia Craton witnessed the emplacement of the Parauapebas Large Igneous Province(LIP)that probably covered a large part of the craton and was associated with the deposition of some of the world largest iron formations.The emplacement of this LIP immediately preceded a period of continental extension that formed a rift infilled first by iron formations followed by terrigenous sediments.This major change of sedimentary regime might have been controlled by the regional tectonic evolution of the Amazonia Craton and its emergence above sea-level.During the Paleoproterozoic,at ca.2.1 Ga,the Rio Fresco Group,consisting of terrigenous sediments from the interior of the Amazonia Craton,was deposited in the Carajás Basin.At that time,the Amazonian lithosphere could have either underwent thermal subsidence forming a large intracratonic basin or could have been deformed by long wavelength flexures that induced the formation of basins and swells throughout the craton under the influence of the growing Transamazonian mountain belt. 展开更多
关键词 Carajás Basin Chemical Abrasion–LA-ICP-MS analyses age distribution comparison Parauapebas Large Igneous Province Transamazonian orogeny
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Molecular analysis of bacterial community in the tap water with different water ages of a drinking water distribution system 被引量:6
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作者 Feng Wang Weiying Li +4 位作者 Yue Li Junpeng Zhang Jiping Chen Wei Zhang Xuan Wu 《Frontiers of Environmental Science & Engineering》 SCIE EI CAS CSCD 2018年第3期89-98,共10页
Bacterial community in the drinking water distribution system (DWDS) was regulated by multiple environmental factors, many of which varied as a function of water age. In this study, four water samples with different... Bacterial community in the drinking water distribution system (DWDS) was regulated by multiple environmental factors, many of which varied as a function of water age. In this study, four water samples with different water ages, including finished water (FW, 0 d) and tap water (TW) [TWI (1 d), TW2(2 d) and TW3(3 d)], were collected along with the mains of a practical DWDS, and the bacterial community was investigated by high-throughput sequencing technique. Results indicated that the residual chlorine declined with the increase of water age, accompanied by the increase of dissolved organic matter, total bacteria counts and bacterial diversity (Shannon). For bacterial community composition, although Proteobacteria phylum (84.12%-97.6%) and Alphaproteobacteria class (67.42c/,~93.09%) kept dominate, an evident regular was observed at the order level. In detail, the relative abundance of most of other residual orders increased with different degrees from the start to the end of the DWDS, while a downward trend was uniquely observed in terms of Rhizobiales, who was inferred to be chlorine-resistant and be helpful for inhibiting pipes corrosion. Moreover, some OTUs were found to be closely related with species possessing pathogenicity and chlorine-resistant ability, so it was recommended that the use of agents other than chlorine or agents that can act synergically with chlorine should be developed for drinking water disinfection. This paper revealed bacterial community variations along the mains of the DWDS and the result was helpful for understanding bacterial ecology in the DWDS. 展开更多
关键词 Bacterial community Water age High-throughput sequencing technique Drinking water distribution system
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The Origin of Spirula spirula (Linne, 1758)
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作者 E. O. Heyfetz 《Journal of Life Sciences》 2018年第1期30-46,共17页
The article presents evidence regarding the origin of Spirula from spiral-shelled forms. The geological age of the species is revised from the Miocene to the Jurassic. The causes of the reorientation of the shell are ... The article presents evidence regarding the origin of Spirula from spiral-shelled forms. The geological age of the species is revised from the Miocene to the Jurassic. The causes of the reorientation of the shell are elucidated. The mode of life of the mollusk is specified. The influence of the theory on facts perception is shown. 展开更多
关键词 BUOYANCY CHAMBERS distribution and geological age GUARD keels mode of life ORIGIN orientation of the shell phragmacone proostracum Spirula L.
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Aging and Migration: Micro and Macro Evidence from China 被引量:4
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作者 Orn B. Bodvarsson Jack W. Hou Kailing Shen 《Frontiers of Economics in China-Selected Publications from Chinese Universities》 2016年第4期548-580,共33页
Post-reform China has been experiencing two major demographic changes: an increasingly aging population and an extraordinary surge of rural-urban migrants. The question we ask is: are these two demographic changes r... Post-reform China has been experiencing two major demographic changes: an increasingly aging population and an extraordinary surge of rural-urban migrants. The question we ask is: are these two demographic changes related? If yes, then, how? The standard view in the migration literature is that the older the migrant, the lower the likelihood of migration. This paper proposes a simple theory of temporary migration for unskilled labor to fit the context of China Motivated by our model, we then use both cross-sectional micro data and panel macro data to examine the potential impacts of aging on migration. We find that shifts in China's age distribution have generated significant changes in the country's migration patterns: migration will shift to closer provinces (probably switching from interprovincial migration to intra-provincial migration) and will concentrate to a few destination provinces. 展开更多
关键词 internal migration age distribution REFORM
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An analysis on the status of female faculty in Chinese higher education
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作者 ZHAO Yezhu 《Frontiers of Education in China》 2007年第3期415-429,共15页
This paper examines the changing status of women faculty through an analysis of statistics on China’s universities from 1994 to 2004.This paper first presents the trend of a drastic increase in women faculty members ... This paper examines the changing status of women faculty through an analysis of statistics on China’s universities from 1994 to 2004.This paper first presents the trend of a drastic increase in women faculty members in recent years.Further details on the academic ranks of women faculty,their age and highest degrees obtained are also presented.A comparison of female representation in faculty ranks is made between China and a few selected countries.Lastly,this paper attempts to account for the low percentage of female professors in higher education.Recommendations for the professional development for women faculty are made in the end. 展开更多
关键词 women faculty higher education age distribution faculty rank academic degree
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