检索结果-南通市图书馆

The point of no return and pectoral angle of Japanese anchovy(Engraulis japonicus) larvae during growth and starvation

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2007年第5期26卷 144-152页

作者： WAN Ruijing LI Xiansen ZHUANG Zhimeng johannessen arne Key Laboratory of Ministry of Agriculture for Sustainable Utilization of Marine Fishery Resources Yellow Sea Fisheries Research Institute Chinese Academy of Fishery Sciences Qingdao 266071 China Department of Biology University of Bergen Bergen Norway

At a temperature of 23.0 - 24.8℃, the mixed feeding of Japanese anchovy larvae was initiated 24 h before the yolk-sac was exhausted. The point of no return （PNR） was reached on the 6th day after hatching. On the 4th day after hatching, the pectoral angle appeared in both fed and unfed anchovy larvae although it was more evident and sharper in the starved and the PNR stage larvae than in the fed ones. According to observations of larvae collected in the sea, the pectoral angles were evident not only in the larvae of 3.62 - 7.44 mm in standard length, but also in the larvae of 2.70 mm in standard length with remnants of yolk. The pectoral angles became diffuse when the larvae reached 7.84 mm and vanished at 9.86 mm. The pectoral angle cannot be used as a criterion to distinguish healthy from starving larvae.

关键词： Engraulis japonicus larvae starvation point of no return (PNR) pectoral angle

Periprocedural complications and one-year outcomes after catheter ablation for treatment of atrial fibrillation in elderly patients:a nationwide Danish cohort study

在线全文

学校读者我要写书评

暂无评论

Journal of Geriatric Cardiology 2021年第11期18卷 897-907页

作者： Jesper Nielsen Kristian Hay Kragholm Sofie Brix Christensen arne johannessen Christian Torp-Pedersen Steen Buus Kristiansen Peter Karl Jacobsen Peter Steen Hansen Mogens Stig Djurhus Christoffer Polcwiartek Peter Søgaard Anna Margrethe Thøgersen Uffe Jakob Ortved Gang Ole Dan Jørgensen Filip Lyng Lindgren Sam Riahi Department of Cardiology Aalborg University HospitalDenmark Department of Cardiology Gentofte HospitalCopenhagen University HospitalDenmark Department of Clinical Research and Cardiology Nordsjaellands HospitalHillerødDenmark Department of Cardiology Skejby University HospitalDenmark Department of Cardiology RigshospitaletCopenhagen University HospitalDenmark Mølholm Clinic VejleDenmark Department of Cardiology Odense University hospitalDenmark Department of Cardiology Roskilde University HospitalDenmark Department of Thoracic Surgery Odense University HospitalDenmark AF-Study group Aalborg University Hospital Denmark Clinical Institute Aalborg UniversityDenmark

OBJECTIVES To investigate complications within 30-days following first-time ablation for atrial fibrillation(AF),including a composite of cardiac tamponade,hematoma requiring intervention,stroke or death,in patients≥75 years of age,compared to pa-tients aged 65−74 *** addition,one-year all-cause mortality and AF relapse were ***&RESULTS All patients receiving their first catheter ablation for AF between 2012 and 2016 were identified us-ing Danish nationwide *** aged 65−74 years served as the reference group for patients≥75 *** of AF within one year was defined as cardioversion following a three-month blanking period,re-ablation or confirmed relapse within *** composite complication outcome did not differ between the two age groups,with 39/1554(2.8%)in patients 65−74 years of age,versus 5/199(2.5%)in older patients(adjusted HR=0.94),95%CI:0.37−2.39,P=0.896).Patients≥75 years or older had no increased hazard of death within 30 days after the procedure,with an incidence of 3/1554(0.2%)in younger pa-tients and 2/199(1.0%)in patients≥75 years of age(adjusted HR=4.71,95%CI:0.78−28.40,P=0.091).There was no difference in relapse of AF after one year between age groups(≥75 years adjusted HR=1.00,95%CI:0.78-1.26,P=0.969).CONCLUSION In patients≥75 years of age selected for catheter ablation for AF,the incidence of periprocedural complica-tions,as well as one-year freedom from AF showed no statistical difference,when compared to patients 65−74 years of age.

关键词： patients fibrillation atrial

Vehicle fuel from biogas with carbon membranes; a comparison between simulation predictions and actual field demonstration

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2018年第3期3卷 266-276页

作者： Shamim Haider arne Lindbrathen Jon Arvid Lie Petter Vattekar Carstensen ThorbjØrn johannessen May-Britt Hagg Norwegian University of Science and Technology NTNUDepartment of Chemical Engineering

The energy contents of biogas could be significantly enhanced by upgrading it to vehicle fuel quality.A pilot-scale separation plant based on carbon hollow fiber membranes for upgrading biogas to vehicle fuel quality was constructed and operated at the biogas plant,Gl?r IKS,Lillehammer *** fuel quality according to Swedish legislation was successfully achieved in a single stage separation *** raw biogas from anaerobic digestion of food waste contained 64±3 mol%CH_4,30–35 mol%CO_2 and less than one percent of N_2 and a minor amount of other *** raw biogas was available at 1.03 bar with a maximum flow rate of 60 Nm^3h^(à1).Pre-treatment of biogas was performed to remove bulk H_2O and H_2S contents up to the required limits in the vehicle fuel before entering to membrane *** membrane separation plant was designed to process 60 Nm^3h^(à1)of raw biogas at pressure up to 21 *** initial tests were,however,performed for the feed flow rate of 10 Nm^3h^(à1)at 21 *** successful operation of the pilot plant separation was continuously run for 192 h(8days).The CH_4 purity of 96%and maximum CH_4 recovery of 98%was reached in a short-term test of 5 *** permeate stream contained over20 mol%CH_4which could be used for the heating *** Hysys~?was integrated with Chem Brane(in-house developed membrane model)to run the simulations for estimation of membrane area and energy requirement of the pilot *** estimation was performed based on simulation data and later compared with actual field results.

关键词： Biogas upgrading Pilot-scale demonstration Membrane separation Process simulations

Decreasing Arctic Sea Ice Mirrors Increasing CO_2 on Decadal Time Scale

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2008年第1期1卷 51-56页

作者： Ola M johannessen Mohn-Sverdrup Center for Global Ocean Studies and Operational Oceanography / Nansen Environmental and Remote Sensing Center Geophysical Institute University of Bergen

Arctic sea ice is a keystone indicator of greenhouse-gas induced global climate change, which is expected to be amplified in the Arctic. Here we directly compare observed variations in arctic sea-ice extent and CO 2 since the beginning of the 20th century, identifying a strengthening linkage, such that in recent decades the rate of sea-ice decrease mirrors the increase in CO 2 , with r ～ -0.95 over the last four decades, thereby indicating that 90% (r 2 ～ 0.90) of the decreasing sea-ice extent is empirically "accounted for" by the increasing CO 2 in the atmosphere. The author presents an empirical relation between annual sea-ice extent and global atmospheric CO 2 concentrations, in which sea-ice reductions are linearly, inversely proportional to the magnitude of increase of CO 2 over the last few decades. This approximates sea-ice changes during the most recent four decades, with a proportionality constant of 0.030 million km 2 per ppmv CO 2 . When applied to future emission scenarios of the Intergovernmental Panel on Climate Change (IPCC), this relationship results in substantially faster ice decreases up to 2050 than predicted by IPCC models. However, departures from this projection may arise from non-linear feedback effects and/or temporary natural variations on interannual timescales, such as the record minimum of sea-ice extent observed in September 2007.

关键词： CO2 increase ice decrease ice projection to2050

Greenland Ice Sheet Contribution to Future Global Sea Level Rise based on CMIP5 Models

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2014年第1期31卷 8-16页

作者： YAN Qing WANG Huijun Ola M.johannessen ZHANG Zhongshi Nansen-Zhu International Research Centre Institute of Atmospheric Physics Chinese Academy of Sciences Nansen Environmental and Remote Sensing Center University of the Chinese Academy of Sciences Climate Change Research Center Chinese Academy of Sciences Nansen Scientific Society Bjerknes Centre for Climate Research Uni Research

Sea level rise （SLR） is one of the major socioeconomic risks associated with global warming. Mass losses from the Greenland ice sheet （GrIS） will be partially responsible for future SLR, although there are large uncertainties in modeled climate and ice sheet behavior. We used the ice sheet model SICOPOLIS （Simulation COde for POLythermal Ice Sheets） driven by climate projections from 20 models in the fifth phase of the Coupled Model Intercomparison Project （CMIP5） to estimate the GrlS contribution to global SLR. Based on the outputs of the 20 models, it is estimated that the GrIS will contribute 0-16 （0-27） cm to global SLR by 2100 under the Representative Concentration Pathways （RCP） 4.5 （RCP 8.5） scenarios. The projected SLR increases further to 7-22 （7-33） cm with 2~basal sliding included. In response to the results of the multimodel ensemble mean, the ice sheet model projects a global SLR of 3 cm and 7 cm （10 cm and 13 cm with 2~basal sliding） under the RCP 4.5 and RCP 8.5 scenarios, respectively. In addition, our results suggest that the uncertainty in future sea level projection caused by the large spread in climate projections could be reduced with model-evaluation and the selective use of model outputs.

关键词： sea level rise Greenland ice sheet ice sheet modeling model evaluation

Climate change in the North- past, present and future

在线全文

学校读者我要写书评

暂无评论

Episodes 2008年第1期31卷 163-167页

作者： Joern Thiede Ola M. johannessen Alfred-Wegner-Institute for Polar and Marine Research in the Helmholtz-Association Am Handelshafen 12 D-27570 Bremerhaven Germany. Nansen Environmental and Remote Sensing Centre （NERSC） Geophysical Institute University of Bergen Thormoehlensgate 47 N-5006 Bergen Norway.

The Nordic countries have produced famous polar explorers and researchers who have generated climate research schools at a variety of locations. The dependence of these countries with respect to the lifelihood of their societies, of their use of lands and seas, the exploitation of marine living and non-living resources have made climate research an eminent topic, and many outstanding discoveries of longand short-term climate change have been made for the first time in Scandinavia. These include early contributions to our understanding of the geological effects of continent-wide glaciations during the ice ages, the complex postglacial history of the Baltic Sea and the varved sediment sequences preserved from lakes with an extraordinary seasonality in their sediment input, as well as the detailed records of temperature, ice texture and impurities and greenhouse gas variations of the last Glacial and of the Holocene preserved in the ice cores from Greenland. Iceland with its volcanic sequences and intercalated sediment layers not only preserved the history of this subaerial segment of the mid-Atlantic Ridge, but also easily datable paleoclimate records. The fate of the Vikings, who settled during the Medieval climate optimum on Iceland and later on Greenland and who lost their habitat on Greenland at the beginning of the Little Ice Age, illustrates vividly the climate-dependent subsistence of the indigenous and non-indigenous Scandinavian populations. Modern Scandinavian climate research institutions also include sophisticated modelling groups.

关键词：气候变化北方地区生存条件地质特征

Mapping sea surface velocities in the Changjiang coastal zone with advanced synthetic aperture radar

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

Acta Oceanologica Sinica 2014年第11期33卷 141-149页

作者： WANG Lihua ZHOU Yunxuan GE Jianzhong johannessen Johnny A. SHEN Fang State Key Laboratory of Estuarine and Coastal Research East China Normal University Nansen Environmental and Remote Sensing Center Geophysical Institute University of Bergen

Range Doppler velocities derived from the Envisat advanced synthetic aperture radar（ASAR） wide swath images are analyzed and assessed against the numerically simulated surface current fields derived from the finite volume coastal ocean model（FVCOM） for the Changjiang Estuary. Comparisons with the FVCOM simulations show that the European Space Agency（ESA） Envisat ASAR based Doppler shift anomaly retrievals have the capability to capture quantitative information of the surface currents in the Changjiang Estuary. The uncertainty analysis of the ASAR range Doppler velocity estimates are discussed with regard to the azimuthal and range bias corrections, radar incidence angles, inaccuracy in the wind field corrections and the presence of rain *** corrected range Doppler velocities for the Changjiang Estuary area are highly valuable as they exhibit quantitative expressions related to the multiscale upper layer dynamics and surface current variability around the East China Sea, including the Changjiang Estuary.

关键词： advanced synthetic aperture radar Changjiang coast Doppler centroid anomaly range Doppler velocity finite volume coastal ocean model

Climate Change in the Subtropical Jetstream during 1950–2009

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2015年第1期32卷 140-148页

作者： B.ABISH P.V.JOSEPH Ola.M.johannessen Nansen Environmental Research Centre India Department of Atmospheric Sciences Cochin University of Science and Technology Nansen Environmental and Remote Sensing Center Nansen Scientific Society

A study of six decades（1950–2009） of reanalysis data reveals that the subtropical jetstream（STJ） of the Southern（Northern） Hemisphere between longitudes 0°E and 180°E has weakened（strengthened） during both the boreal winter（January,February） and summer（July, August） seasons. The temperature of the upper troposphere of the midlatitudes has a warming trend in the Southern Hemisphere and a cooling trend in the Northern Hemisphere. Correspondingly, the north–south temperature gradient in the upper troposphere has a decreasing trend in the Southern Hemisphere and an increasing trend in the Northern Hemisphere, which affects the strength of the STJ through the thermal wind relation. We devised a method of isotach analysis in intervals of 0.1 m s-1in vertical sections of hemispheric mean winds to study the climate change in the STJ core wind speed, and also core height and latitude. We found that the upper tropospheric cooling of the Asian mid-latitudes has a role in the strengthening of the STJ over Asia, while throughout the rest of the globe the upper troposphere has a warming trend that weakens the STJ. Available studies show that the mid-latitude cooling of the upper troposphere over Asia is caused by anthropogenic aerosols（particularly sulphate aerosols） and the warming over the rest of the global mid-latitude upper troposphere is due to increased greenhouse gases in the atmosphere.

关键词： subtropical jetstream upper troposphere greenhouse gases aerosols

Population increase impacts the climate,using the sensitive Arctic as an example

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2022年第2期15卷 71-74页

作者： Ola M.johannessen Elena V.Shalina Nansen Scientific Society BergenNorway Nansen International Environmental and Remote Sensing Centre St.PetersburgRussia Institute of Earth Sciences St.Petersburg State UniversityRussia

The global population during the last 100 years has increased from 2 to 7.7 billion,causing an increase in greenhouse gases in the *** order to see how population increase is directly related to physical variables of the climate,this Perspective article places observations and scenarios of climate change into context and puts forth a statistical modeling study on how the sensitive Arctic climate responds to the increasing *** relationships between population,Arctic sea-ice extent(SIE),and surface air temperature(SAT)are very strong,with the increasing population explaining 96%of the decreasing SIE and about 80%of the increasing SAT in the *** projection for the SIE using the population as a“proxy predictor”for a projected population of 10 billion people on the Earth in 2100,yields a SIE of 9.30 and 8.21 million km 2 for a linear and squared relationship,respectively,indicating no“tipping point”for the annual ice extent in this *** adds another dimension to climate understanding for the public at large using population as a proxy variable,instead of the more abstract CO_(2)*** also indicates that it is important to attempt to limit the ongoing increase in population,which is the main cause of the greenhouse gas emissions,in addition to reducing per capita emissions by an exponential increase in implementing renewable energy,a formidable challenge in this century.

关键词： Population Climate Sea ice Arctic