检索结果-南通市图书馆

The Long-term Survival Chances of Young Massive Star Clusters

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Astronomy and Astrophysics 2007年第2期7卷 155-186页

作者： Richard de Grijs Geneviève Parmentier Department of Physics & Astronomy The University of Sheffield Hicks Building Hounsfield Road Sheffield S3 7RH U. K.National Astronomical Observatories Chinese Academy of SciencesBeijing 100012 Institute of Astrophysics & Geophysics Université de LiègeAllée du 6 Aot17Sart-Tilman (B5c)B-4000 LiègeBelgium

We review the long-term survival chances of young massive star clusters （YMCs）, hallmarks of intense starburst episodes often associated with Violent galaxy interactions. We address the key question as to whether at least some of these YMCs can be considered protoglobular clusters （GCs）, in which case these would be expected to evolve into counterparts of the ubiquitous old GCs believed to be among the oldest galactic building blocks. In the absence of significant external perturbations, the key factor determining a cluster＇s long-term survival chances is the shape of its stellar initial mass function （IMF）. It is, however, not straightforward to assess the IMF shape in unresolved extragalactic YMCs. We discuss in detail the promise of using high-resolution spectroscopy to make progress towards this goal, as well as the numerous pitfalls associated with this approach. We also discuss the latest progress in worldwide efforts to better understand the evolution of entire cluster systems, the disruption processes they are affected by, and whether we can use recently gained insights to determine the nature of at least some of the YMCs observed in extragalactic starbursts as proto-GCs. We conclude that there is an increasing body of evidence that GC formation appears to be continuing until today; their long-term evolution crucially depends on their environmental conditions, however.

关键词： stellar dynamics - globular clusters general - galaxies interactions - Magellanic Clouds - galaxies starburst - galaxies star clusters

Roles of Solar UV Radiation in Photosynthetic C-fixation in Surface Seawater of South China Sea:The Double-edged Sword

在线全文

学校读者我要写书评

暂无评论

Roles of Solar UV Radiation in Photosynthetic C-fixation in ...

evaluation and examination of a Possible Shoe‑polish Trace in a Hold‑up Case

中国海洋湖沼学会藻类学分会第七届会员大会暨第十四次学术讨论会

作者： Villafae ve Helbling eW Marine Biology Institute Shantou UniversityShantouGuangdong515063China Estación de Fotobiología Playa Unión & Consejo Nacional de Investigaciones Cientificas y Técnicas(CONICET)Casilla de Correos N° 15(9103) RawsonChubutArgentina

Solar UV radiation(UVR,280-400 nm)is a permanent environmental factor that is attenuated by seawater and causes a variety of biological effects within the euphotic *** levels of atmospheric CO2 and solar UV-B(280-315 ...

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

Journal of Forensic Science and Medicine 2016年第4期2卷 233-244页

作者： Line Gueissaz Tacha Hicks Cyril Muehlethaler Geneviève Massonnet Faculty of Law Criminal Justice and Public AdministrationSchool of Criminal JusticeUniversity of LausanneLausanne 1015Switzerland Fondation Pour la Formation Continue Universitaire Lausannoise Lausanne1015Switzerland Department of Chemistry City College of the City University of New YorkNew York 10031USA

In this article,we show how the Bayesian framework can be applied to a hold‑up case involving a possible shoe‑polish trace according to one of the *** article highlights the importance of interpreting data from the beginning of the examination through the preassessment *** a set of alternative propositions in agreement with the information provided by the parties is chosen,one can establish what is needed in the ***,limited data were available to assign factors such as transfer and rarity of the ***,we showed how specific case‑tailored experiments provide meaningful data for *** this case,the police had observed a trace on the jacket of a person who reported to have been pushed with the offender’s gun during the hold‑up *** the jacket was submitted to our laboratory,the exact nature of the trace was *** from this trace were collected and analyzed by stereomicroscopy,microscopy,and infrared *** obtained results supported that this trace was waxy *** literature dealing with the analysis of waxy materials generally uses solvent extraction‑based ***,as our analytical sequence allowed a good discrimination of different waxy products of known origin,we considered that this methodology was ***,it did not involve.any extraction step that could lead to undesired compounds from the substrate(e.g.,dyes and additives).This article therefore suggests an alternative.analytical sequence for the analysis of such material in casework.

关键词： Bayesian evaluation firearms trace evidence transfer

Cadmium sulfide thin films growth by chemical bath deposition

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

Journal of Semiconductors 2018年第3期39卷 50-56页

作者： S.Hariech M.S.Aida J.Bougdira M.Belmahi G.Medjahdi D.Genève n.Attaf H.Rinnert Thin films and Interfaces Laboratory Faculty of Sciences Mentouri University Department of physics Faculty of science King Abdulaziz University Jean Lamour Institute University of Lorraine

Cadmium sulfide（Cd S） thin films have been prepared by a simple technique such as chemical bath deposition（CBD）. A set of samples Cd S were deposited on glass substrates by varying the bath temperature from 55 to 75 °C at fixed deposition time（25 min） in order to investigate the effect of deposition temperature on Cd S films physical properties. The determination of growth activation energy suggests that at low temperature Cd S film growth is governed by the release of Cd^（2＋） ions in the solution. The structural characterization indicated that the Cd S films structure is cubic or hexagonal with preferential orientation along the direction（111） or（002）, respectively. The optical characterization indicated that the films have.a fairly high transparency, which varies between55% and 80% in the visible range of the optical spectrum, the refractive index varies from 1.85 to 2.5 and the optical gap value of which can reach 2.2 e V. It can be suggested that these properties make these films perfectly suitable for their use as window film in thin films based solar cells.

关键词： thin films chemical bath cadmium sulfide solar cell

Morphological Change in the northern Red River Delta,Vietnam

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2018年第6期17卷 1272-1280页

作者： BUI Vuong Van FAn Daidu nGUYen Dac ve TRAn Dinh Lan TRAn Duc Thanh HOAnG Van Long nGUYen Thi Hong Hanh Institute of Marine environment and Resources Vietnam Academy of Science and TechnologyHaiphong 18000Vietnam State Key Laboratory of Marine Geology Tongji UniversityShanghai 200092China Hanoi University of Mining and Geology Hanoi 10000Vietnam Graduate University of Science and Technology Vietnam Academy of Science and TechnologyHanoi 10000Vietnam

Coastal erosion has become a worldwide concern, typically in the densely populated Asian mega-river deltas. Severe coastal erosion in the southern Red River Delta(RRD) has been intensively studied. Coastal morphological change in the northern RRD was examined in detail through DeM(Digital elevation Model) analysis based on time series of bathymetrical maps(1965–2004) and Landsat images(1975–2015) in this study. The results show that the northern RRD is featured by rapid coastal accretion in the past few decades, although suspended sediment flux has dropped by roughly 60% after the completeness of Hoa Binh Dam(HBD) in 1988 and relative sea level rose at 1.9 mm yr^(-1). However, accretion at the outer part of subtidal shoals and platforms was observed to slow down quickly or even turned into erosion in the last two decades. The resuspended sediments from the erosion zone can be transported landward to replenish the inner coastal zone, keeping the latter accretion in the near future to compensate for the sediment discharge decrease from the river. However, this lag effect should be terminated soon if other adverse effects go worse, e.g., damming rivers, sea-level rising, strengthening storms, land reclamation and other poor-designed coastal engineering. Coastal planners and managers should pay full attention to these changes.

关键词： Morphological change DeM coastal erosion coastal engineering coastal management tide-dominated Red River Delta

Prevalence of vacA, cagA and babA2 genes in Cuban Helicobacter pylori isolates

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2009年第2期15卷 204-210页

作者： Lino e Torres Karelia Melián Arlenis Moreno Jordis Alonso Carlos A Sabatier Mayrín Hernández Ludisleydis Bermúdez Boris L Rodríguez Department of Microbiology and Immunology Biotechnology Division National Centre for Scientif ic Research Ciudad de La Habana Cuba Department of Gastroenterology Medical and Chirurgic Research Centre (CIMEQ) Ciudad de La Habana Cuba Anatomopathology Department Medical and Chirurgic Research Centre (CIMEQ) Ciudad de La Habana Cuba

AIM： To investigate the prevalence of vacuolating cytotoxin （vacA）, cytotoxin associated gene A （cagA） and blood adhesion binding antigen （babA2） genotypes of Helicobacter pylori （H pylori） isolates from Cuban dyspeptic patients. MeTHODS： DnA was extracted from Hpylori-positive cultures taken from 130 dyspeptic patients. Genotyping was performed by PCR, using specific primers for vacA （s1, s2, m1, m2）, cagA and babA2 genes. endoscopic observations and histological examinations were used to determine patient pathologies. ReSULTS： vacA alleles s1, s2, m1 and m2 were detected in 96 （73.8%）, 34 （26.2%）, 75 （57.7%） and 52 isolates （40%）, respectively, while the cagA gene was detected in 95 isolates （73.2%）. One hundred and seven isolates （82.3%） were babA2-positive. A significant correlation was observed between vacAs1m1 and cagA and between vacAs1ml and babA2 genotypes （P 〈 0.001 and P 〈 0.05, respectively） and between babA2 genotype and cagA status （P 〈 0.05）; but, no correlation was observed between vacAsl and babA2 genotypes. eighty five （65.4%） and 73 （56.2%） strains were type 1 （vacAsl-cagA-positive） and ＂triplepositive＂（vacAs1-cagA-babA2-positive）, respectively, and their presence was significantly associated with duodenal ulcer （P 〈 0.01 and P 〈 0.001, respectively）. COnCLUSIOn： The distribution of the main virulence factors in the Cuban strains in this study resembled that of the Western-type strains, and the more virulent H pylori isolates were significantly associated with duodenal ulcer, ulcer disease being the worst pathology observed in the group studied.

关键词： Cuban dyspeptic patients He/icobacterpylori vacA, cagA and babA

effect of micro-algae Schizochytrium *** in plant diet on reproduction of female rainbow trout(Oncorhynchus mykiss):maternal programming impact of progeny

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

Journal of Animal Science and Biotechnology 2022年第4期13卷 1175-1192页

作者： emilie Cardona emilien Segret Yoann Cachelou Thibaut Vanderesse Laurence Larroquet Alexandre Hermann Anne Surget Geneviève Corraze Frederic Cachelou Julien Bobe Sandrine Skiba-Cassy InRAe Univ.Pau&Pays AdourE2S UPPANuMéAF-64310Saint Pée-sur-NivelleFrance InRAe UR1037 Fish Physiology and Genomic laboratoryF-35000 RennesFrance Viviers de Sarrance F-64490SarranceFrance Viviers de Rébénacq F-64260RébénacqFrance.

Background:The broodstock diet,and in particular the lipid and fatty acid composition of the diet,is known to play a key role in reproductive efficiency and survival of the progeny in fish.A major problem when replacing both fish meal and fish oil by plant sources is the lack of n-3 long chain polyunsaturated fatty acids,such as eicosapentaenoic acid(ePA)and docosahexaenoic acid(DHA).To address this problem,we studied the effect of the plant-based diet supplemented with Schizochytrium ***,source of DHA,compared to a conventional commercial diet rich in fish meal and fish oil on reproductive performance and egg quality and the consequences on progeny,in female rainbow trout ***:The results demonstrated that DHA-rich microalgae supplementation in a plant-based diet allowed for the maintenance of reproductive performance and egg quality comparable to a conventional commercial feed rich in fish meal and fish oil and led to an increased significant fry survival after ***,when females were fed a plant-based diet supplemented with micro-algae,the 4-month-old progenies showed a significant higher growth when they were challenged with a similar diet as broodstock during 1 *** provide evidence for metabolic programming in which the maternal dietary induced significant protracted effects on lipid metabolism of ***:The present study demonstrates that supplementation of a plant-based diet with DHA-rich microalgae can be an effective.alternative to fish meal and fish oil in rainbow trout broodstock aquafeed.

关键词： egg quality Micro-algae nutritional programming Plant diet Rainbow trout Reproduction

Relations between mercury fractions and microbial community components in seawater under the presence and absence of probable phosphorus limitation conditions

在线全文

学校读者我要写书评

暂无评论

Journal of environmental Sciences 2019年第1期31卷 145-162页

作者： Igor ?ivkovi? vesna Fajon Jo?e Kotnik Yaroslav Shlyapnikov Kristina Obu Vazner ermira Begu Stefanija ?estanovi? Danijela ?anti? Ana Vrdoljak Slaven Jozi? Mladen ?oli? Jelena Lu?i? Jere ve.a Grozdan Ku?pili? Marin Ordulj Frano Mati? Branka Grbec natalia Bojani? ?ivana nin?evi? Gladan Milena Horvat Department of environmental Sciences Jo?ef Stefan Institute Jo?ef Stefan International Postgraduate School ecological engineering Institute Maribor 2000 Slovenia Laboratory of Marine Microbiology Institute of Oceanography and FisheriesSplit 21000 Croatia Laboratory of Chemical Oceanography and Sedimentology of the Sea Institute of Oceanography and FisheriesSplit 21000 Croatia Laboratory of Chemical Oceanography and Sedimentology of the Sea Institute of Oceanography and Fisheries Department of Marine Studies University of SplitSplit 21000 Croatia Laboratory of Physical Oceanography Institute of Oceanography and FisheriesSplit 21000 Croatia Laboratory of Plankton and Shellfish Toxicity Institute of Oceanography and FisheriesSplit 21000 Croatia

Microbial transformations of toxic monomethylmercury(MMHg) and dissolved gaseous mercury(DGM) at the lower levels of the marine food web are not well understood, especially in oligotrophic and phosphorus-limited seas. To examine the effects of probable phosphorus limitation(~PP-limitation) on relations between mercury(Hg) fractions and microorganisms, we determined the total mercury(THg), total methylated mercury(MeHg), DGM, and microbiological and chemical parameters in the Central Adriatic Sea. Using statistical analysis, we assessed the potential microbial effects on Hg transformations and bioaccumulation. Only in the absence of ~PP-limitation conditions(^(nO–P)P-limitation) is MeHg significantly related to most chemical and microbial parameters, indicating metabolism-dependent Hg *** heterotrophic activity of low nucleic acid bacteria(abundant in oligotrophic regions)seems responsible for most of Hg methylation under ^(nO–P)P-limitation. Under these conditions,DGM is strongly related to microbial fractions and chlorophyll a, indicating biological DGM production, which is probably not metabolically induced, as most of these relations are also observed underPP-limitation. MMHg biomagnification was observed through an increased bioaccumulation factor from microseston to mesozooplankton. Our results indicate that Hgtransformations and uptake might be enhanced under ^(nO–P)P-limitation conditions, emphasizing their impact on the transfer of Hg to higher trophic levels.

关键词： Mercury speciation Methylmercury Probable phosphorus limitation Microbial community

Simulations of the Performance of Maximum Power Point Tracking Algorithms Based on experimental Data According to the Topologies of DC-DC Converters

在线全文

学校读者我要写书评

暂无评论

Journal of Power and energy engineering 2021年第5期9卷 76-92页

作者： Abraham Dandoussou Pierre Kenfack Stève ngoffe Perabi Martin Kamta University of Buea Department of Electrical and Power Engineering Higher Technical Teachers’ Training College (HTTTC) Kumba Cameroon University of Douala Department of Electrical Engineering and Industrial Computing Institut Universitaire de Technologie Douala Cameroon University of ngaoundere Department of Electrical Engineering Energetic and Automation National School of Agro-Industrial Sci-ences Ngaoundere Cameroon

Maximum Power Point Tracking (MPPT) algorithms are now widely used in PV systems independently of the weather conditions. In function of the application, a DC-DC converter topology is chosen without any previous performance test under normal weather conditions. This paper proposes an experimental evaluation of MPPT algorithms according to DC-DC converters topologies, under normal operation conditions. Four widely used MPPT algorithms i.e. Perturb and Observe (P & O), Hill Climbing (HC), Fixed step Increment of Conductance (InCF) and Variable step Increment of Conductance (InCV) are implemented using two topologies of DC-DC converters i.e. buck and boost converters. As input variables to the PV systems, recorded irradiance and temperature, and extracted photovoltaic parameters (ideality factor, series resistance and reverse saturation current) were used. The obtained results show that buck converter has a lot of power losses when controlled by each of the four MPPT algorithms. Meanwhile, boost converter presents a stable output power during the whole day. Once more, the results show that INCV algorithm has the best performance.

关键词： MPPT Algorithms DC-DC Converters Photovoltaic Parameters normal Operating Conditions