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Forces and energetics of intermittent swimming

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Acta Mechanica Sinica 2017年第4期33卷 725-732页

作者： Daniel Floryan Tyler Van Buren alexander j.Smits Department of Mechanical and Aerospace Engineering Princeton University Princeton NJ 08544 USA

Experiments are reported on intermittent swimming motions. Water tunnel experiments on a nominally two-dimensional pitching foil show that the mean thrust and power scale linearly with the duty cycle, from a value of 0.2 all the way up to continuous motions, indicating that individual bursts of activity in intermittent motions are independent of each other. This conclusion is corroborated by particle image velocimetry（PIV） flow visualizations, which show that the main vortical structures in the wake do not change with duty cycle. The experimental data also demonstrate that intermittent motions are generally energetically advantageous over continuous motions. When metabolic energy losses are taken into account, this conclusion is maintained for metabolic power fractions less than 1.

关键词： intermittent swimming maintained conclusion cycle thrust favorable producing aquatic circles

Interaction of Radiation and Turbulent Natural Convection:A Pseudo-Direct Numerical Study

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Advances in Applied Mathematics and Mechanics 2022年第6期14卷 1567-1586页

作者： alexander Nee Ali j.Chamkha Research and Educational Center of I.N.Butakov National Research Tomsk Polytechnic UniversityTomskRussia Faculty of Engineering Kuwait College of Science and TechnologyDoha DistrictKuwait

This paper presents a hybrid lattice Boltzmann solver for turbulent buoyancy-driven flow coupled with surface thermal *** two-relaxation time scheme for the Boltzmann equation combined with the implicit finite difference scheme for the energy equation is implemented to compute the heat transfer and fluid flow *** accuracy and robustness of the hybrid approach proposed in this study are assessed in terms of the numerical and experimental data of other *** performing the simulation,the Rayleigh number is ranged from 108 to 1010 whereas the surface emissivity is changed from zero to *** computations,it is found that the overall temperature of the cavity is increased as a result of enhancing the surface *** plumes are formed both at the isothermal and the thermally-insulated walls with the Ra109 and#*** the conditions under study,the overall heat transfer rate is raised by around 5%when taking into account the surface thermal radiation.

关键词： Pseudo-direct numerical simulation surface radiation hybrid lattice Boltzmann scheme turbulent natural convection.

Update in the treatment of intracranial atherosclerotic disease

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Stroke & Vascular Neurology 2020年第1期5卷 59-64页

作者： Zachary R Barnard Michael j.alexander Neurosurgery Cedars-Sinai Medical CenterLos AngelesCaliforniaUSA

This review highlights the recent evolution of the imaging,medical management,surgical options and endovascular therapies for symptomatic intracranial atherosclerotic disease(IcaD).Recent imaging developments including optical coherence tomography and other modalities to assess the intracranial arteries for symptomatic IcaD are reviewed,not only to diagnose IcaD but to determine if IcaD plaques have any high-risk features for *** future developments in the treatment of IcaD are discussed,including the development of trackable drug-coated balloons for the cerebral circulation to treat primary or restenotic arteries,new iterations of self-expanding intracranial stents with easier delivery systems,and the re-examination of indirect surgical bypass techniques for *** addition to these important technological developments,however,is the evolving evidence regarding the best treatment window for these techniques and additional factors in medical management which can improve patient outcomes in this devastating pathology.

关键词： intracranial balloon arteries

Counting your sperm before they fertilize： are sperm counts really declining？

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Asian j.urnal of Andrology 2013年第2期15卷 179-183,I0004,I0005页

作者： alexander W Pastuszak Dolores j.Lamb Scott Department of Urology Baylor College of Medicine Houston TX 77030 USA Center for Reproductive Medicine Baylor College of Medicine Houston TX 77030 USA Department of Molecular Cell Biology Baylor College of Medicine Houston TX 77030 USA

Apurported global decline in sperm counts has been a source of controversy since the early 1990s. Numerous studies performed since then, as well as reanalysis of the original data, show either no changes, or even increases, in sperm concentrations over time. In this review, we discuss the 1992 meta-analysis that initiated the continuing debate on whether sperm concentrations are declining, and the com- munity discussion surrounding it over the past two decades. We also highlight studies evaluating sperm concentrations performed since the initial study that produced different results, and conclude that no definitive cause for a decrease in sperm counts has been established, and the effects of geography and environment on sperm counts are unclear.

关键词： YOUNG DANISH MEN SEMEN QUALITY DECREASING QUALITY LIFE-STYLE REGIONAL DIFFERENCES GENERAL-POPULATION MALE-INFERTILITY HEALTHY-MEN FINNISH MEN AREA

Designation of a new genus Bathymenes for the deep-sea pontoniine shrimps of the 'Periclimenes alcocki species group'(Decapoda,caridea,Palaemonidae),with a checklist of the species assigned to the genus

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Chinese j.urnal of Oceanology and Limnology 2016年第1期34卷 170-176页

作者：寇琦李新正 alexander j.BRUCE Institute of Oceanology Chinese Academy of Sciences Crustacea Section Queensland Museum

A new genus of the deep-sea pontoniine shrimps,Bathymenes gen. nov.,is established for the 'Periclimenes alcocki species group' of the genus Periclimenes Costa,1844. The new genus is distinguished from other genera of the Pontoniinae by a combination of characters: the posteriormost dorsal rostral tooth remote from other teeth,situated in the epigastric position,cornea usually reduced,the propodus of second pereiopods covered with fine granules,the dactylus of the maj.r second chela being generally flanged,the ambulatory pereiopods with the dactyli being biunguiculate and telson with more than two pairs of dorsolateral spines. The genus is mainly distributed in the tropical to warm-temperate Indo-West Pacific waters at depths greater than 200 m. Fifteen species previously recognized as belonging to the 'P.a lcocki species group' are now placed in Bathymenes gen. nov. A key for their identification and a checklist of congeneric species are provided.

关键词： Palaemonidae Pontoniinae Periclimenes Bathymenes deep-sea new genus

Integrated Risk Identification, Analysis, and Assessment:A Dynamic Household Economy Analysis Methodology and Example

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International j.urnal of Disaster Risk Science 2013年第2期4卷 77-88页

作者： Bob alexander Linda j.Cox j.nko Mochizuki Rural Livelihood Risk Management Consulting P.O.Box 1251HonoluluHI 96807USA Department of Natural Resource and Environmental Management University of Hawai`i at ManoaHonoluluHI 96822USA

Many methodologies identify, analyze, and assess static risks to quantify potential disaster losses based on past and current events. Static methodologies will not, however, capture how climate change and adaptation are rapidly affecting the natural and social systems in many areas. Local and global changes such as those associated with development investments, livelihood pressures, political stability, and demographic trends are also affecting many areas, especially in emerging economies. Risk identification, analysis, and assessment methodologies must integrate all changes dynamically so that risk reduction and development decisions can be based on future needs. After a theoretical explanation of how to integrate dynamic changes, a static Household Economy Analysis(HEA) completed for a rapidly changing area of East Timor was altered using current trends to make the analysis more dynamic. Some inherent difficulties exist with a more dynamic approach and recommendations for overcoming them are presented. Research, government, and nongovernment personnel interested in integrated approaches to risk reduction and development decision-making in areas subj.ct to rapid change will find the study useful.

关键词： integrate disaster interested

Nitridation of Ni-based alloys:thermodynamics,kinetics,and deformation phenomena accompanying internal precipitation

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Rare Metals 2006年第5期25卷 501-511页

作者： alexander A.Kodentsov j.rma K.Kivilahti Frans j.j.van Loo Laboratory of Materials and Interface Chemistry Eindhoven University of TechnologyP.O.Box 5135600 MBEindhovenThe Netherlands Laboratory of Electronics Production Technology Helsinki University of TechnologyFIN-02150 EspooFinland

When a moderately stable phase is precipitated out during an intemal reaction, the behaviour of the penetrating atoms within the diffusion zone can be interpreted based on thermodynamic considerations. Evidence for “up-hill” diffusion of the penetrating species through the matrix towards the precipitation front during the intemal nitridation of Ni-Cr alloys at 1125℃ and 6000 bar of N2-pressure was predicted. Such behaviour of nitrogen is opposite to the boundary conditions in Wagner＇s description of internal reactions. A volume change associated with the precipitation reaction resulted in a stress gradient between the alloys surface and the intemal nitridation front. Stress relief occurred mainly by transport of nickel to the gas/metal interface. Pipe diffusion-controlled creep is the dominant stress accommodation mechanism during nitriding of dilute Ni-Cr alloys at 700℃ under a flowing NH3 ＋ H2 gas mixture.

关键词： nitridation nickel alloys thermodynamics diffusion internal precipitation

Behaviors that predict personality components in adult free-ranging Tibetan macaques Macaca thibetana

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Current Zoology 2014年第3期60卷 362-372页

作者： alexander j. PRITCHARD Lori K. SHEERAN Kara I. GABRIEL j.n-Hua LI Ronald S. WAGNER Department of Anthropology Rutgers University New Brunswick NJ 08901 USA Department of Anthropology Central Washington University Ellensburg WA 98926 USA Department of Psychology Central Washington University Ellensburg WA 98926 USA School of Resource and Environmental Engineering Anhui University Hefei 230601 China School of Life Science Anhui Normal University Hefei 230601 China Department of Biology Central Washington University Ellensburg WA 98926 USA

To further the potential for applied personality studies, we present a methodology for assessing personality in nonhu man animals without a priori assumptions, using behavioral measures to discriminate personality survey results. Our study group consisted of 12 freeranging, provisioned, adult Tibetan macaques Macaca thibetana at the Valley of the Wild Monkeys, China. We asked familiar Chinese park guards and scientists to rate each of the 12 macaques using 27item personality surveys. We also recorded behavioral observations （〉 100 hrs） from AugustSeptember, 2012. The personality surveys showed reliability in 22 of the items that were then utilized in a principal component analysis that revealed five components： Insecurity, Reactivity, Boldness, Sociability, and Leadership. Prior personality research on Macaca show comparable components. In order to determine which behaviors would best predict those five personality components, we conducted discriminant analyses using behavioral measures as predictors. We found that behavioral measures of avoidance, lunging, feargrinning, selfdirected behaviors, touching, proximity and chasing could significantly predict personality component scores in certain situations. Finally, we analyzed the effects of situation （provisioning and tourists） and found situation influenced proximity and rates of avoidance and selfdirected behaviors. Wider implementation of this methodology may permit longterm analysis of personality using behavioral proxies for established personality traits, in particular on research investigating the effects of tourism and provisioning on personality .

关键词： Tourism Provisioning Temperament Surveys Personality Primate

Overview and Lessons Learned for Increasing Influenza Vaccination Coverage Among Healthcare Workers in the United States

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China CDC weekly 2020年第44期2卷 862-866页

作者： Ying Song alexander j.Millman Influenza Division Centers for Disease Control and PreventionAtlantaGAUSA

Vaccinating healthcare workers(HCWs)annually against influenza is a key strategy for protecting HCWs,preventing nosocomial outbreaks and mortality(particularly among high-risk patient populations),and reducing work absenteeism during the influenza season(1–4).Vaccinated HCWs have also been shown to be more likely to recommend influenza vaccination to their patients(5–7).

关键词： mortality annually vaccination