检索结果-南通市图书馆

HⅠ emission from the red giant Y CVn with the VLA and FAST

Research in Astronomy and Astrophysics 2017年第7期17卷 39-46页

作者： Do T.Hoai pham T.nhung Lynn D.Matthews Eric Grard Thibaut Le Bertre Department of Astrophysics Vietnam National Satellite CenterVAST LERMA CNRSObservatoire de Paris/PSLSorbonne Universite's Department of Astrophysics Vietnam National Satellite Center MIT Haystack Observatory GEPI CNRSObservatoire de Paris/PSL

Imaging studies with the Very Large Array（VLA） have revealed H I emission associated with the extended circumstellar shells of red giants. We analyze the spectral map obtained on Y CVn, a J-type carbon star on the Asymptotic Giant Branch. The H I line profiles can be interpreted with a model of a detached shell resulting from the interaction of a stellar outflow with the local interstellar *** reproduce the spectral map by introducing a distortion along a direction corresponding to the star＇s motion in space. We then use this fitting to simulate observations expected from the Five-hundred-meter Aperture Spherical radio Telescope（FAST）, and discuss its potential for improving our description of the outer regions of circumstellar shells.

关键词： stars AGB and post-AGB-- stars carbon - stars individual Y CVn - radio lines stars

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

越南大米国际竞争力，竞争力提升与出口替代市场研究

越南大米国际竞争力，竞争力提升与出口替代市场研究

引用

作者： pham THI CAM nhung（范氏锦绒）西北农林科技大学

学位级别：硕士

越南是全球主要的农业国之一。农业占国内生产总值(GDP)的24%,出口的20%,提供全国70%就业岗位。其中,稻米种植是越南经济的重要组成部分,占据农业总产出的30%。越南在稻米生产方面具有优势,在过去的时期中,稻米出口量曾经超过印度、泰... 详细信息

越南是全球主要的农业国之一。农业占国内生产总值(GDP)的24%,出口的20%,提供全国70%就业岗位。其中,稻米种植是越南经济的重要组成部分,占据农业总产出的30%。越南在稻米生产方面具有优势,在过去的时期中,稻米出口量曾经超过印度、泰国和巴基斯坦等国。然而,随着时间的推移,越南在稻米出口的优势逐渐减弱,相对于其他国家而言不再具有优势。由于全球经济一体化和新冠疫情的冲击,越南的稻米行业目前面临一定的挑战。本研究旨在确定越南大米出口的竞争力,并提出增强措施。该研究还探讨了主要大米进口国的需求,并探索越南大米的替代市场以增加出口能力。本研究运用绝对优势和比较优势经济理论位基础,评估了越南大米生产效率、土地可用性、生产成本、出口价格和产品质量。并使用显示比较优势指标(RCA)和出口比较优势指标(XCA)指数分析了越南大米出口的竞争力,出口多元化指标(HI)指数测量了主要大米出口国的产品多样化程度和进口需求比较指标(ICN)指数衡量进口国对大米的需求。研究通过2010年至2021年的UNComtrade数据梳理比较了印度、巴基斯坦、泰国、美国和越南等全球前五大大米出口国的大米生产情况。研究显示从2010年到2021年,美国的大米产量最高,其次是越南。印度一直拥有最大的大米种植面积,而越南的大米种植面积从2010年到2021年有显著下降。通过五个国家在2003-2021年的RCA得分显示越南在大米生产和出口方面的比较优势正在下降,而印度的比较优势一直保持稳定。印度、巴基斯坦和泰国一直在大米生产和出口方面处于领先地位。越南的大米竞争优势正在下降,而美国的竞争优势非常低。由于印度能够以低廉的价格出口大量大米,XCA分析表明印度是全球前15个国家中最具竞争力的大米出口国。泰国、越南和巴基斯坦也是高度具有竞争力的大米出口国,因为它们拥有较大种植面积、低廉的价格。相比之下,美国、中国和缅甸在全球大米出口市场上的竞争力较弱,这表明它们可能需要提高生产能力或降低价格以保持出口竞争力。越南在大米出口的XCA指数中排名第三。全球大米出口市场由印度、泰国、巴基斯坦和越南主导,其中印度的份额正在增加,而泰国和巴基斯坦保持稳定。相比之下越南的出口市场多样化程度较低。本文还探讨了主要进口国的大米进口需求、竞争、增长机会和市场趋势。根据研究结果,越南向主要进口大米国家出口了大量大米。菲律宾从越南进口了86.13%的大米,新加坡则从越南进口了30.21%的大米。有趣的是,中国内地和中国香港进口了大量大米,越南分别为这两个市场提供了27.09%和25.78%的大米。越南还向沙特阿拉伯、美国、贝宁、埃塞俄比亚、日本、南非、法国、阿联酋、德国、加拿大、肯尼亚、马达加斯加和英国出口大米,但其份额在0.01%至7.80%之间。根据研究,为了增加越南全球市场份额,越南大米产业需要政府和非政府支持。研究建议政府应加大研发的投入、改善灌溉系统、使用更高质量的种子和改善农业技术。越南需要改善其营销和品牌推广策略,创造一个独特的大米品牌,并推出有效的营销活动来吸引潜在客户。研究还建议非政府组织可以通过提供技术援助、倡导政策变革和推动公平贸易来帮助越南大米产业。这些策略可以提高越南的大米产出和小农户的收入。

关键词：国际贸易大米越南比较优势需求

来源：

同方学位论文库评论

在线全文

同方学位论文库

学校读者我要写书评

暂无评论

Assessment of the Quality of Frozen-Thawed Semen or Epididymal Sperm in Three Native Vietnamese Pig Breeds

引用

Open Journal of Animal Sciences 2023年第3期13卷 283-297页

作者： Van Khanh Nguyen Huong Thu Thi Vu Huong Le Thi Nguyen Huong Thi Nguyen Au Thi Hoang Dat Van Le nhung tuyet Thi Nguyen Hieu Trung Phan Yen Kim Thi pham Son Phan Le Quynh Anh Le Quynh Anh Le Lan Doan pham Minh Quang Luu Muoi Thi Nguyen Key Laboratory of Animal Cell Biotechnology National Institute of Animal Science Hanoi Vietnam National Institute of Animal Science Hanoi Vietnam Ministry of Science and Technology Hanoi Vietnam Animal Experiments and Domestic Animal Conservation Center National Institute of Animal Science Hanoi Vietnam

Our aim was to evaluate the quality of ejaculated and epididymal frozen-thawed pig sperm of endangered Vietnam native pig breeds. Ejaculated sperm was collected from live boars and epididymal sperm was collected from slaughtered boars of the MuongTe, Kieng Sat and Co BinhThuan breeds and frozen in 0.25 ml straws using a protocol established earlier for modern pig breeds. We evaluated the sperm quality after thawing in terms of motility and rates of viable and abnormal spermatozoa. Our results revealed that the sperm motility and rates of viable and abnormal frozen-thawed sperm were >30%, >44%, and 0.05). In the Co BinhThuan breed, the rate of pregnancy of ejaculated groups was similar to that of the epididymal group. In conclusion, the ejaculated and epididymal sperm of native Vietnamese pigs were successfully frozen. We succeeded in creating embryos in vitro and pregnant pigs after artificial insemination from frozen-thawed semen in three native Vietnamese pig breeds for the first time. The use of the ejaculated sperm improved the production of native pig embryos in vitro efficiency.

关键词： Native Vietnamese Pig In Vitro Porcine Embryo Epididymal Ejaculate Artificial Insemination

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Comparison of HIV Testing among Children and Adults with Tuberculosis, Vietnam

引用

Journal of Tuberculosis Research 2017年第4期5卷 292-297页

作者： Tyson Volkmann Binh Nguyen Ebelechukwu G. Anyalechi Kimberly N. Chapman Hedges Ho Van Anh pham Quang Tue Nguyen Viet nhung Eleanor S. Click Division of Global HIV and TB Centers for Disease Control and Prevention Atlanta USA Division of Tuberculosis Elimination Centers for Disease Control and Prevention Atlanta USA Vietnam National Tuberculosis Program Hanoi Vietnam

HIV testing among persons with tuberculosis (TB) results in high-yield identification of persons infected with HIV. To evaluate differences in HIV testing among children versus adults with TB in Vietnam, we collected and analyzed age-disaggregated facility and aggregated provincial data from the National Tuberculosis Program. HIV testing was incompletely documented for >70% of children, whereas adult testing data were >90% complete. Standardized training of personnel for universal HIV testing and documentation for children with TB could improve HIV case-detection and permit linking of children with HIV to antiretroviral treatment to prevent morbidity and mortality.

关键词： Surveillance Operational Research Childhood TB Pediatric

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Effect of Combinations of Sucrose and Cryoprotectants on the Survival of Catfish Embryos （Pangasidae hypophthamus）

引用

Journal of Agricultural Science and Technology(B) 2013年第12期3卷 887-892页

作者： Nguyen Thi Hong Nguyen Thi nhung Nguyen Thi Uoc Nguyen Trung Thanh Nguyen Thi Hiep Nguyen Van Hanh pham Van Khanh Ha Thi Ngoc Nga Truong Van Thuong Bui Xuan Nguyen Department of Embryo Biotechnology Institute of Biotechnology Vietnam Academy of Science and Technology 18-Hoang QuocViet Hanoi 8404 Vietnam Department of Environment and Pathology Research Institute for Aquaculture No. 2 Cai Be Tien Giang 8473 Vietnam Research Institute for Aquaculture No. 1 Dinh Bang Tu Son Bac Ninh 84241 Vietnam

Although cryopreservation of embryos has been used in most terrestrial animals, the application of this technique has not been succeeded for aquatic animals. In this study, the authors investigate the effect of different combinations of sucrose （SUC, C12H22OH） and cryoprotectants （CPAs） on the survival of the catfish embryos （Pangasidae hypophthalmus） at low temperatures （4, 0 and -20 ℃） for short-term storage. For this aim, embryos with somites and optic cups were exposed to different combinations of sucrose with methanol （SUC ＋ MeOH）, 1.2-propylene glycol （SUC ＋ PROH） and ethylene glycol （SUC ＋ EG） at four concentrations ratios：（1） 0.5 M SUC ＋ 0.5 M CPA; （2） 1 M SUC ＋ 0.5 M CPA; （3） 0.5 M SUC ＋ 1 M CPA; （4） 1 M SUC ＋ 1 M CPA for 40 min at 4, 0 and -20 ℃. Embryos kept in water at room temperature （RT）, 4, 0 and -20℃ were used as controls. The survival rate was expressed as a percentage of hatched embryos per total embryos treated. The results showed that the hatching rate declined significantly when embryos were stored in water at 0 ℃ and -20℃. For embryos at 0 ℃ storage, the highest survival rate （87.78%） was obtained with 1 M SUC ＋ 1 M MeOH combination while at -20 ℃, only embryos in the combined treatments of 0.5 M SUC ＋ 1 MEG and 0.5 M SUC ＋ 1 M PROH reached the hatching stage （40% and 83.33%, respectively）. In conclusion, the results showed that the catfish embryos are sensitive to sub-zero temperatures and the combined treatment of 0.5 M sucrose and 1 M propylene glycol can be used to protect catfish embryos from damages caused by low temperature （0 ℃ and -20 ℃）.

关键词： Catfish cryoprotectants embryos low temperature sucrose.

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Ecoregional variations of aboveground biomass and stand structure in evergreen broadleaved forests

引用

Journal of Forestry Research 2020年第5期31卷 1713-1722页

作者： Tran Van Do Mamoru Yamamoto Osamu Kozan Vo Dai Hai Phung Dinh Trung Nguyen Toan Thang Lai Thanh Hai Vu Thanh Nam Trieu Thai Hung Hoang Van Thang Tran Duc Manh Cao Chi Khiem Vu Tien Lam Nguyen Quang Hung Tran Hoang Quy pham Quang Tuyen Trinh Ngoc Bon Nguyen Thi Thu Phuong Ninh Viet Khuong Nguyen Van Tuan Dang Thi Hai Ha Tran Hai Long Dang Van Thuyet Dang Thinh Trieu Nguyen Van Thinh Tran Anh Hai Duong Quang Trung Nguyen Van Bich Dinh Hai Dang pham Tien Dung Nguyen Huy Hoang Le Thi Hanh Phan Minh Quang Nguyen Thi Thuy Huong Hoang Thanh Son Nguyen Thanh Son Nguyen Thi Van Anh Nguyen Thi Hoai Anh pham Dinh Sam Hoang Thi nhung Hoang Van Thanh Nguyen Huu Thinh Tran Hong Van Ho Trung Luong Bui Kieu Hung Research Institute for Sustainable Humanosphere Kyoto UniversityUjiKyotoJapan Silviculture Research Institute Vietnamese Academy of Forest SciencesNorth Tu LiemHanoiVietnam Center for Southeast Asian Studies Kyoto UniversityKyotoJapan Vietnamese Academy of Forest Sciences North Tu LiemHanoiVietnam Vietnam Administration of Forestry No.2 Ngoc HaBa DinhHanoiVietnam

Biotic and abiotic factors control aboveground biomass(AGB)and the structure of forest *** study analyses the variation of AGB and stand structure of evergreen broadleaved forests among six ecoregions of Vietnam.A data set of 1731-ha plots from 52 locations in undisturbed old-growth forests was *** results indicate that basal area and AGB are closely correlated with annual precipitation,but not with annual temperature,evaporation or hours of *** area and AGB are positively correlated with trees>30 cm *** areas surveyed(52.6%)in these old-growth forests had AGB of 100–200 Mg ha^-1;5.2%had AGB of 400–500 Mg ha^-1,and 0.6%had AGB of>800 Mg ha^-*** percent of the areas surveyed had stand densities of 300–600 ***^-1,and 64%had basal areas of 20–40 m^2 ha^-*** is an important factor influencing the AGB of old-growth,evergreen broadleaved forests in *** causing the loss of large-diameter trees(e.g.,>100 cm DBH)affects AGB but may not seriously affect stand density.

关键词： Aboveground biomass Carbon storage Climatic variables Ecoregion Edaphic variables Oldgrowth forest

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Evaluating the yield of systematic screening for tuberculosis among three priority groups in Ho Chi Minh City,Viet Nam

引用

Infectious Diseases of Poverty 2020年第6期9卷 16-28页

作者： Luan Nguyen Quang Vo Andrew James Codlin Rachel Jeanette Forse NgaThuy Nguyen Thanh Nguyen Vu Giang Truong Le Vinh Van Truong Giang Chau Do Ha Minh Dang Lan Huu Nguyen Hoa Binh Nguyen nhung Viet Nguyen Jens Levy Knut Lonnroth SBertel Squire Maxine Caws Friends for International TB Relief 68B Nguyen Van Troi8Phu NhuanHo Chi Minh CityViet Nam Interactive Research and Development Ho Chi Minh CityViet Nam Ho Chi Minh City Public Health Association Ho Chi Minh CityViet Nam pham Ngoc Thach Hospital Ho Chi Minh CityViet Nam National Lung Hospital Ha NoiViet Nam KNCV Tuberculosefonds The HagueThe Netherlands Department of Global Public Health Karolinska InstitutetStockholmSweden Department of Clinical Sciences Liverpool School of Tropical MedicineLiverpoolUK Birat Nepal Medical Trust LazimpatKathmanduNepal

Background: In order to end tuberculosis(TB),it is necessary to expand coverage of TB care services,including systematic screening ***,more evidence is needed for groups among whom systematic screening is only conditionally recommended by the World Health *** study evaluated concurrent screening in multiple target groups using community health workers(CHW).Methods:: In our two-year intervention study lasting from October 2017 to September 2019,CHWs in six districts of Ho Chi Minh City,Viet Nam verbally screened three urban priority groups:(1)household TB contacts;(2)close TB contacts;and(3)residents of urban priority areas without clear documented exposure to TB including hotspots,boarding homes and urban *** persons were referred for further screening with chest radiography and follow-on testing with the Xpert MTB/RIF *** individuals with normal or without radiography results were tested on smear *** described the TB care cascade and characteristics for each priority group,and calculated yield and number needed to ***,we fitted a mixed-effect logistic regression to identify the association of these target groups and secondary patient covariates with TB treatment ***: We verbally screened 321020 people including 24232 household contacts,3182 social and close contacts and 293606 residents of urban priority *** resulted in 1138 persons treated for TB,of whom 85 were household contacts,39 were close contacts and 1014 belonged to urban priority area *** yield of active TB in these groups was 351,1226 and 345 per 100000,respectively,corresponding to numbers needed to screen of 285,82 and *** fitted model showed that close contacts[adjusted odds ratio(aOR)=2.07;95%CI:1.38–3.11;P<0.001]and urban priority area residents(aOR=2.18;95%CI:1.69–2.79;P<0.001)had a greater risk of active TB than household ***: The study detected a large number of un

关键词： Case detection Tuberculosis Active case finding Urban Viet nam

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：