检索结果-南通市图书馆

入侵植物根茎的生长和竞争力因相邻植物的不同而不同

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2021年第4期14卷 638-647页

作者： Alyssa Laney smith Daniel Z.Atwater Wonjae Kim David C.Haak Jacob n.Barney School of Plant and Environmental Sciences Virginia TechBlacksburgVAUSA Department of Biology Earlham CollegeRichmondINUSA Present address:Department of Ecology and Evolutionary Biology University of ArizonaTucsonAZUSA

物种内的遗传和表型变异对进化过程的影响已众所周知,但人们对种内变异如何影响群落水平过程还知之甚少。在人类对自然系统造成影响的大背景下,由于人类活动可能会产生巨大的选择压力,因此具有生态意义的种内变异可能会特别重要。在一... 详细信息

物种内的遗传和表型变异对进化过程的影响已众所周知,但人们对种内变异如何影响群落水平过程还知之甚少。在人类对自然系统造成影响的大背景下,由于人类活动可能会产生巨大的选择压力,因此具有生态意义的种内变异可能会特别重要。在一项温室实验中,我们研究了一种分布广泛的入侵物种和农业杂草石茅(Sorghum halepense)在受到种间竞争、种内竞争和土壤肥力的影响时,其在生物量和根茎方面发生的种内变异和生态型变异。与我们的预期和此前的研究结果不同的是,我们并没有在这一早期生命阶段中发现石茅各生态型生物量的改变。然而,我们确实发现石茅的生物量会随着竞争植株种类和土壤施肥方式的不同而发生很显著的变化,同时不同株之间也存在很大差异。农业生态型的根茎较其它生态型大了11%,经施肥处理后的增大幅度更高至3倍;虽然施肥后的根茎生物量增加了~50%,但生态型之间却并无差异。有趣的是,当受到种内竞争时,与玉米(Zea mays)发生种间竞争时的情况相比,石茅的生物量和根茎生物量产出分别减少了32%和20%。我们的研究结果表明,针对相邻植株的种类而发生的物种特异性竞争响应以及根茎分配的改变,石茅在受竞争时可能会产生适应性响应,从而使分配情况发生改变。

关键词：适应农业竞争外来入侵选择石茅(Sorghum halepense)

Where were the monsoon regions and arid zones in Asia prior to the Tibetan Plateau uplift?

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

national Science Review 2015年第4期2卷 403-416页

作者： Xiaodong Liu Qingchun Guo Zhengtang Guo Zhi-Yong Yin Buwen Dong Robin smith State Key Laboratory of Loess and Quaternary Geology Institute of Earth Environment Chinese Academy of Sciences CAS Center for Excellence in Tibetan Plateau Earth Sciences University of the Chinese Academy of Sciences Key Laboratory of Cenozoic Geology and Environment Institute of Geology and Geophysics Chinese Academy of Sciences Department of Environmental & Ocean Sciences University of San Diego national Centre for Atmospheric Science University of Reading

The impact of the Tibetan Plateau uplit on the Asian monsoons and inland arid climates is an important but also controversial question in studies of paleoenvironmental change during the Cenozoic. In order to achieve a good understanding of the background for the formation of the Asian monsoons and arid environments, it is necessary to know the characteristics of the distribution of monsoon regions and arid zones in Asia before the plateau uplit. In this study, we discuss in detail the paterns of distribution of the Asian monsoon and arid regions before the plateau uplit on the basis of modeling results without topography from a global coupled atmosphere–ocean general circulation model, compare our results with previous simulation studies and available biogeological data, and review the uncertainties in the current knowledge. Based on what we know at the moment, tropical monsoon climates existed south of 20?n in South and Southeast Asia before the plateau uplit, while the East Asian monsoon was entirely absent in the extratropics. hese tropical monsoons mainly resulted from the seasonal shits of the Inter-Tropical Convergence Zone. here may have been a quasi-monsoon region in central-southern Siberia. Most of the arid regions in the Asian continent were limited to the latitudes of 20–40?n, corresponding to the range of the subtropical high pressure year-around. In the meantime, the present-day arid regions located in the relatively high latitudes in Central Asia were most likely absent before the plateau uplit. he main results from the above modeling analyses are qualitatively consistent with the available biogeological data. hese results highlight the importance of the uplit of the Tibetan Plateau in the Cenozoic evolution of the Asian climate patern of dry–wet conditions. Future studies should be focused on efects of the changes in land–sea distribution and atmospheric CO2 concentrations before and ater the plateau uplit, and also on cross-comparisons between numer

关键词： the Tibetan Plateau uplit the Asian monsoons

Ultra-broadband metamaterial absorbers from long to very long infrared regime

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2021年第8期10卷 1462-1473页

作者： Yu Zhou Zheng Qin Zhongzhu Liang Dejia Meng Haiyang Xu David R.smith Yichun Liu State Key Laboratory of Applied Optics Changchun Institute of OpticsFine Mechanics and PhysicsChinese Academy of Sciences130033 ChangchunJilinChina. University of Chinese Academy of Sciences 100049 BeijingChina. Center for Advanced Optoelectronic Functional Materials Research and Key Laboratory of UV Light-Emitting Materials and Technology of Ministry of Education College of PhysicsNortheast Normal University130024 ChangchunChina. Center for Metamaterials and Integrated Plasmonics Duke UniversityP.O.Box 90291DurhamNC 27708USA

Broadband metamaterials absorbers with high absorption,ultrathin thickness and easy configurations are in great demand for many potential *** this paper,we first analyse the coupling resonances in a Ti/Ge/Ti three-layer absorber,which can realise broadband absorption from 8 to 12 *** we experimentally demonstrate two types of absorbers based on the Ti/Ge/Si_(3)n_(4)/Ti *** taking advantage of coupling surface plasmon resonances and intrinsic absorption of lossy material Si_(3)n_(4),the average absorptions of two types of absorbers achieve almost 95%from 8 to 14μm(experiment result:78%from 6.5 to 13.5μm).In order to expand the absorption bandwidth,we further propose two Ti/Si/SiO_(2)/Ti absorbers which can absorb 92%and 87%of ultra-broadband light in the 14-30μm and 8-30μm spectral range,*** findings establish general and systematic strategies for guiding the design of metamaterial absorbers with excellent broadband absorption and pave the way for enhancing the optical performance in applications of infrared thermal emitters,imaging and photodetectors.

关键词： absorber absorption coupling

Melioidosis in India and Bangladesh: A review of case reports

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2018年第5期11卷 320-329页

作者： Meghan Tipre Paul Vijay Kingsley Tamika smith Mark Leader nalini Sathiakumar Department of Epidemiology School of Public HealthUniversity of Alabama Pantai Hospital Ipoh

Objective: To conduct an epidemiological and clinical review of published case reports of melioidosis from India and Bangladesh. Methods: Data from published case reports were abstracted and summarized. We further compared the clinical epidemiology of the melioidosis cases in India with case series from highly endemic areas in northern Australia and Southeast Asia to elucidate any differences in presentations and risk factors between the ***: We identified a total of 99 cases published between 1953 and June 2016, originating from India(n=85) or Bangladesh(n=14). Cases were predominantly male and ranged in age from 1 month to 90 years. Diabetes mellitus was the most common risk factor reported(58%). About 28% of the cases had history of exposure via high-risk occupations or exposure to contaminated water. The overall case fatality rate(CFR) was 26%. Factors influencing mortality included the occurrence of septic shock(CFR, 80%), environmental exposure(CFR,39%), primary presentation of pneumonia(CFR, 38%), misdiagnosed and/or mistreated cases(CFR, 33%) or the presence of a risk factor(CFR, 29%). Because of the small number of cases in Bangladesh, pattern of clinical epidemiology is limited to India. Soft tissue abscess(37%)was the most common clinical presentation reported from India followed by pneumonia(24%)and osteomyelitis/septic arthritis(18%). neurological melioidosis(n=10, 12%) presented as pyemic lesions of the brain or meninges. A few cases of prostatic abscess(n=4) in men and parotid abscess(n=4) were also noted. The above patterns were consistent with case series from Southeast Asia and northern Australia for the most part, in terms of risk factors associated with infection and factors influencing mortality. Differences included clinical presentation of pneumonia which was notably lower than that reported in Southeast Asia and northern Australia; a higher proportion of neurological and parotid abscess presentation; and a lower CFR compared to th

关键词： Melioidosis India Bangladesh Burkholderia pseudomallei Environmental

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

实验性人牙颈部缺损的扫描电镜研究

实验性人牙颈部缺损的扫描电镜研究

Age and sex specific timing, frequency, and spatial distribution of horseshoe crab spawning in Delaware Bay:Insights from a large-scale radio telemetry array

全国第四次牙体牙髓病学术会议

作者：王嘉德 B．G．n.smith 北京医科大学口腔医学院伦敦大学GuY氏医院牙科学院

＜正＞用扫描电镜观察12对双尖牙在模拟横刷牙、酸蚀和力分别或联合作用后颈部形成的缺损表面结构和剖面硬组织的改变;缺损表面的改变反映了三种因素协同致损的结果;缺损剖面观察到了釉质和牙本质的微裂和损伤,说明模拟的力在实验...

＜正＞用扫描电镜观察12对双尖牙在模拟横刷牙、酸蚀和力分别或联合作用后颈部形成的缺损表面结构和剖面硬组织的改变;缺损表面的改变反映了三种因素协同致损的结果;缺损剖面观察到了釉质和牙本质的微裂和损伤,说明模拟的力在实验过程中,使牙颈部硬组织发生了应力疲劳

关键词：

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Current Zoology 2010年第5期56卷 563-574页

作者： David R.smith Lorne J.BROUSSEAU Mary T. MAnDT Michael J.MILLARD USGS Leetown Science Center Cornell University Cooperative Extension U.S. Fish and Wildlife Service

To study horseshoe crab Limulus polyphemus spawning behavior and migration over a large-spatial extent (>100 km),we arrayed fixed station radio receivers throughout Delaware Bay and deployed radio transmitters and archival tags on adulthorseshoe crabs prior to their spawning *** tagged and released 160 females and 60 males in 2004 and 217 females *** array covered approximately 140 km of *** rates were >70% with multi-year *** categorizedadult age by carapace *** females tended to spawn earlier in the season and more frequently than young females,but those tendencies were more apparent in 2004 when spawning overall occurred earlier than in 2005 when spawning was delayedpossibly due to decreased water *** of initial spawning within a year was correlated with water *** adjusting for day of first spring tide,the day of first spawning was 4 days earlier for every 1 degree (℃) rise in meandaily water temperature in *** nine % of spawning occurred during nighttime high *** five % of spawning occurredwithin 3 d of a spring tide,which was slightly higher than the 47% expected if spawning was uniformly distributed regardlessof tidal *** the same spawning season,males and females were observed spawning or intertidally resting atmore than one beach separated by >5 *** years,most (77%) did not return to spawn at the same *** ofstranding was strongly age dependent for males and females with older adults experiencing higher stranding *** staging in the shallow waters east of the channel spawned exclusively along the eastern (nJ) shoreline,but those stagingwest of the channel spawned throughout the ***,several insights emerged from the use of radio telemetry,which advancesour understanding of horseshoe crab ecology and will be useful in conserving the Delaware Bay horseshoe crab populationand

关键词：产卵时间无线电遥测年龄空间分布马蹄阵列性别蟹

Impact of Tillage and Fertilizer Application Method on Gas Emissions in a Corn Cropping System

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

Pedosphere 2012年第5期22卷 604-615页

作者： K. smith D. WATTS T. WAY H. TORBERT S. PRIOR Department of Math Science and Technology University of Minnesota Crookston Crookston MN 56716 (USA) USDA-ARS national Soil Dynamics Laboratory 411 S. Donahue Dr. Auburn AL 36832 (USA)

Tillage and fertilization practices used in row crop production are thought to alter greenhouse gas emissions from soil. This study was conducted to determine the impact of fertilizer sources, land management practices, and fertilizer placement methods on greenhouse gas (CO2, CH4, and n2O) emissions. A new prototype implement developed for applying poultry litter in subsurface bands in the soil was used in this study. The field site was located at the Sand Mountain Research and Extension Center in the Appalachian Plateau region of northeast Alabama, USA, on a Hartsells fine sandy loam (fine-loamy, siliceous, subactive, thermic Typic Hapludults). Measurements of carbon dioxide (CO2), methane (CH4), and nitrous oxide (n2O) emissions followed GRACEnet (greenhouse gas reduction through agricultural carbon enhancement network) protocols to assess the effects of different tillage (conventional vs. no-tillage) and fertilizer placement (subsurface banding vs. surface application) practices in a corn (Zea mays L.) cropping system. Fertilizer sources were urea-ammonium nitrate (UAn), ammonium nitrate (An) and poultry litter (M) applied at a rate of 170 kg ha-1 of available n. Banding of fertilizer resulted in the greatest concentration of gaseous loss (CO2 and n2O) compared to surface applications of fertilizer. Fertilizer banding increased CO2 and n2O loss on various sampling days throughout the season with poultry litter banding emitting more gas than UAn banding. Conventional tillage practices also resulted in a higher concentration of CO2 and n2O loss when evaluating tillage by sampling day. Throughout the course of this study, CH4 flux was not affected by tillage, fertilizer source, or fertilizer placement method. These results suggest that poultry litter use and banding practices have the potential to increase greenhouse gas emissions.

关键词：温室气体排放量耕作方式施肥方法裁剪系统玉米间套作 CH4通量家禽粪便

Prevalence of significant liver disease in human immunodeficiency virus-infected patients exposed to Didanosine: A cross sectional study

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

World Journal of Hepatology 2016年第36期8卷 1623-1628页

作者： Sarah Logan Alison Rodger Laura Maynard-smith James O'Beirne Thomas Fernandez Filippo Ferro Colette smith Sanjay Bhagani the Ian Charleson Day Centre Ground Floor Royal Free London NHS Foundation Trust Research Department of Infection and Population Health University College London Department of Hepatology Nambour General Hospital Sunshine Coast Hospital and Health Service

AIM To identify significant liver disease [including nodular regenerative hyperplasia(nRH)] in asymptomatic Didanosine(DDI) exposed human immunodeficiency virus(HIV) positive *** Patients without known liver disease and with > 6 mo previous DDI use had liver stiffness assessed by transient elastography(TE). Those with alanine transaminase(ALT) above upper limit normal and/or TE > 7.65 k Pa underwent ultrasound scan(U/S). Patients with:(1) abnormal U/S; or(2) elevated ALT plus TE > 7.65 k Pa;or(3) TE > 9.4 k Pa were offered trans-jugular liver biopsy(TJLB) with hepatic venous pressure gradient(HVPG) *** ninety-nine patients were recruited, median age 50 years(range 31-70), 81% male and 70% men who have sex with men. ninety-five percent with VL n antiretroviral therapy with median CD4 count 639 IU/L. Median DDI exposure was 3.4 years(range 0.5-14.6). Eighty-one had a valid TE readings(interquartile range/score ratio nd 4(6%) > 9.4 k Pa. Seventeen(17%) met criteria for TJLB, of whom 12 accepted. All had HVPG nest histological findings were steatosis(n = 6), normal architecture(n = 4) and nRH(n = 2), giving a prevalence of previously undiagnosed nRH of 2%(95%CI: 0.55%, 7.0%).COnCLUSIOn A screening strategy based on TE, liver enzymes and U/S scan found a low prevalence of previously undiagnosed nRH in DDI exposed, asymptomatic HIV positive patients. Patients were more likely to have steatosis highlighting the increased risk of multifactorial liver disease in this population.

关键词：榴状的再生增生人的免疫不全病毒脂肪变性非肝脏硬化症的门高血压 Didanosine

Self-management of coronary heart disease in older patients after elective percutaneous transluminal coronary angioplasty

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

老年心脏病学杂志：英文版 2016年第5期13卷 393-400页

作者： Susan Dawkes Graeme D smith Lawrie Elliott Robert Raeside Jayne H Donaldson School of nursing Midwifery and Social Care Edinburgh Napier University Scotland United Kingdom Department of nursing and Community Health Glasgow Caledonian University Scotland United Kingdom Employment Research Institute Edinburgh Napier University Scotland United Kingdom School of Health Sciences University of Stirling Scotland United Kingdom

OBJECTIVE:To explore how older patients self-manage their coronary heart disease (CHD) after undergoing elective percutaneous transluminal coronary angioplasty (PTCA).;METHODS:This mixed methods study used a sequential, explanatory design and recruited a convenience sample of patients (n = 93) approximately three months after elective PTCA. The study was conducted in two phases. Quantitative data collected in Phase 1 by means of a self-administered survey were subject to univariate and bivariate analysis. Phase 1 findings informed the purposive sampling for Phase 2 where ten participants were selected from the original sample for an in-depth interview. Qualitative data were analysed using thematic analysis. This paper will primarily report the findings from a sub-group of older participants (n = 47) classified as 65 years of age or older.;RESULTS:78.7% (n = 37) of participants indicated that they would manage recurring angina symptoms by taking glyceryl trinitrate and 34% (n = 16) thought that resting would help. Regardless of the duration or severity of the symptoms 40.5% (n = 19) would call their general practitioner or an emergency ambulance for assistance during any recurrence of angina symptoms. Older participants weighed less (P = 0.02) and smoked less (P = 0.01) than their younger counterparts in the study. Age did not seem to affect PTCA patients' likelihood of altering dietary factors such as fruit, vegetable and saturated fat consumption (P = 0.237).;COnCLUSIOnS:The findings suggest that older people in the study were less likely to know how to correctly manage any recurring angina symptoms than their younger counterparts but they had fewer risk factors for CHD. Age was not a factor that influenced participants' likelihood to alter lifestyle factors.

关键词：自我管理冠状动脉老年人冠心病患者成形腔内单因素方差分析