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LINEAR WAVEs THAT EXPREss THE sIMPLEsT POssIBLE PERIODIC sTRUCTURE OF THE COMPREssIBLE EULER EQUATIONs

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Acta Mathematica scientia 2009年第6期29卷 1749-1766页

作者： Blake Temple Robin young Department of Mathematics University of California Davis CA 95616 USA Department of Mathematics and statistics University of Massachusetts Amherst MA 01003 USA

In this paper we show how the simplest wave structure that balances compression and rarefaction in the nonlinear compressible Euler equations can be represented in a solution of the linearized compressible Euler equations. such waves are exact solutions of the equations obtained by linearizing the compressible Euler equations about the periodic extension of two constant states separated by entropy jumps. Conditions on the states and the periods are derived which allow for the existence of solutions in the Fourier 1-mode. In [3, 4, 5] it is shown that these are the simplest linearized waves such that, for almost every period, they are isolated in the kernel of the linearized operator that imposes periodicity, and such that they perturb to nearby nonlinear solutions of the compressible Euler equations that balance compression and rarefaction along characteristics in the formal sense described in [3]. Their fundamental nature thus makes them of interest in their own right.

关键词： compressible Euler periodic solutions conservation laws

Precambrian supercontinents,glaciations,atmospheric oxygenation,metazoan evolution and an impact that may have changed the second half of Earth history

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Geoscience Frontiers 2013年第3期4卷 247-261页

作者： Grant M.young Department of Earth sciences Western University1151 Richmond Street NLondonOntarioCanada N6A 5B7

In more than 4 Ga of geological evolution, the Earth has twice gone through extreme climatic perturba- tions, when extensive glaciations occurred, together with alternating warm periods which were accom- panied by atmospheric oxygenation. The younger of these two episodes of climatic oscillation preceded the Cambrian ＂explosion＂ of metazoan life forms, but similar extreme climatic conditions existed between about 2.4 and 2.2 Ga. Over long time periods, changing solar luminosity and mantle temperatures have played important roles in regulating Earth＇s climate but both periods of climatic upheaval are associated with supercontinents. Enhanced weathering on the orogenically and thermally buoyed supercontinents would have stripped CO2 from the atmosphere, initiating a cooling trend that resulted in continental glaciation. Ice cover prevented weathering so that CO2 built up once more, causing collapse of the ice sheets and ushering in a warm climatic episode. This negative feedback loop provides a plausible explanation for multiple glaciations of the Early and Late Proterozoic, and their intimate association with sedimentary rocks formed in warm climates. Between each glacial cycle nutrients were flushed into world oceans, stimulating photosynthetic activity and causing oxygenation of the atmosphere. Accommodation for many ancient glacial deposits was provided by rifting but escape from the climatic cycle was predicated on break- up of the supercontinent, when flooded continental margins had a moderating influence on weathering. The geochemistry of Neoproterozoic cap carbonates carries a strong hydrothermal signal, suggesting that they precipitated from deep sea waters, overturned and spilled onto continental shelves at the termination of glaciations. Paleoproterozoic （Huronian） carbonates of the Espanola Formation were probably formed as a result of ponding and evaporation in a hydrothermally influenced, restricted rift setting. Why did metazoan evolution not take off a

关键词： Proterozoic supercontinents Glaciations Impacts Oxygenation Metazoa

China, Like the Us, Faces Challenges in Achieving Inclusive Growth through Manufacturing

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China & World Economy 2020年第2期28卷 3-17页

作者： Robert Z.lawrence Peterson Institute for International Economics

For more than three decades the goal of becoming "the factory of the world" has been at the core of China s development *** strategy,in combination with high rates of domestic investment and low rates of consumption,has made Chinese production the most manufacturing intensive in the *** as its wages have risen,China's competitiveness in the most labor-intensive manufacturing industries has *** ability to assemble products remains a major source of its exports,but it has also tried to shift toward more sophisticated value-added production *** domestic spending has shifted away from investment toward consumption as citizens'income has *** Americans,Chinese are also spending more on services than on manufactured *** of these changes are fundamentally altering the structure of China s production,reducing the role of manufacturing and increasing the skill levels of workers in *** paper reviews the challenges posed by these developments for China s long-term goal of achieving more inclusive *** presents evidence that the commonly held perceptions that Chinese manufacturing employment growth is robust are *** fact,such growth has peaked and China is now following a pattern of structural change that is typical of a more mature emerging economy,in which the share of employment in manufacturing declines as workers are increasingly employed in services.

关键词： employment inclusive growth inequality labor manufacturing

THE VACUUM IN NONIsENTROPIC GAs DYNAMICs

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Acta Mathematica scientia 2012年第1期32卷 339-351页

作者： Geng Chen Robin young Department of Mathematics Pennsylvania State University University Park PA 16802 USA Department of Mathematics University of Massachusetts Amherst MA 01003 USA

We investigate the vacuum in nonisentropic gas dynamics in one space vari- able, with the most general equation of states allowed by thermodynamics. We recall physical constraints on the equations of state and give explicit and easily checkable conditions under which vacuums occur in the solution of the Riemann problem. We then present a class of models for which the Riemann problem admits unique global solutions without vacuums.

关键词： nonisentropic gas dynamics conservation laws vacuum large data Riemann problem

A convergence analysis for a class of practical variance-reduction stochastic gradient MCMC

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science China(Information sciences) 2019年第1期62卷 67-79页

作者： Changyou CHEN Wenlin WANG Yizhe ZHANG Qinliang sU lawrence CARIN Department of Computer science and Engineering Department of Electrical and Computer Engineering Duke University Microsoft Research school of Data and Computer science Sun Yat-sen University

stochastic gradient Markov chain Monte Carlo(sG-MCMC) has been developed as a flexible family of scalable Bayesian sampling algorithms. However, there has been little theoretical analysis of the impact of minibatch size to the algorithm’s convergence rate. In this paper, we prove that at the beginning of an sG-MCMC algorithm, i.e., under limited computational budget/time, a larger minibatch size leads to a faster decrease of the mean squared error bound. The reason for this is due to the prominent noise in small minibatches when calculating stochastic gradients, motivating the necessity of variance reduction in sG-MCMC for practical use. By borrowing ideas from stochastic optimization, we propose a simple and practical variance-reduction technique for sG-MCMC, that is efficient in both computation and *** importantly, we develop the theory to prove that our algorithm induces a faster convergence rate than standard sG-MCMC. A number of large-scale experiments, ranging from Bayesian learning of logistic regression to deep neural networks, validate the theory and demonstrate the superiority of the proposed variance-reduction sG-MCMC framework.

关键词： Markov chain Monte Carlo sG-MCMC variance reduction deep neural networks

Wyoming Integrated Test Center Fostering new-generation technology for today’s energy resources

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Clean Energy 2020年第1期4卷 85-87页

作者： sarah young Public Affairs and Communications Wyoming Infrastructure Authority325 W.18th StreetSuite#1CheyenneWY 82001

1 summary The Wyoming Integrated Test Center(ITC)is a research test facility located on the site of Basin Electric Power Cooperative’s Dry Fork station(https://***/Facilities/Dry-Fork)near Gillette,Wyoming,*** ITC provides space for researchers to test Carbon Capture,Utilization and sequestration(CCUs)technologies using actual coal-based flue *** ITC is one of only a handful of facilities around the world that enables researchers to test their technologies at an operating power plant.

关键词： CCUs Foster enable

Exploring perspectives in assessing the quality of governance of the Reducing Emissions from Deforestation and Forest Degradation (REDD+) pilot project in Cambodia: Use of Q Methodology

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Journal of Mountain science 2020年第1期17卷 95-116页

作者： sareth NHEM young-jin LEE Graduate school National University of Ma nagementPhnom Penh 1220Cambodia Techo sen school of Government&/nrernadona/Relations The University of CambodiaPhnom Penh 1220Cambodia College of Industrial science Graduate School of Natural SciencesDepartment of Forest ResourcesKonju National UniversityYesan-gun 32439South Korea

Public and policy makers alike are concerned about national and global deforestation and forest degradation. These issues pose a significant threat to social, economic and environmental *** to prevent forest loss and increased attention to pilot REDD+ projects in community forestry sites would both deliver rural livelihood benefits and help to reduce adverse climate ***, there has been no significant exploration of the viewpoints of local experts to determine the monitoring and action needed to support communitybased forestry and improve the governance of REDD+pilot projects in Cambodia. Therefore, this study aimed to assess the perceptions of local stakeholders towards the quality of governance of the first community forest REDD+ pilot project in Cambodia,employing Q-methodology. We adapted 11 indicators of the hierarchical framework of assessment of governance quality to design 40 Q-statements related to REDD+ governance or achievements. The 52 P-set ranked these Q-statements with respect to the community-based REDD+ pilot project. Our study revealed that local stakeholders held four distinct, and partially opposite, views, that:(1) the REDD+ project is successful because it is inclusiveness and capable of causing behavioral change;(2) REDD+ pilot projects should be led by government, not external or locally;and needs more resources;(3) the REDD+ pilot project has raised unrealistic expectations, would likely be a source of corruption and will probably not be successful for local people or halting deforestation;and(4) the REDD+ pilot project is inclusive but not very transparent and probably ineffective at protecting forest. Through these four varied perspectives from local people involved in the project,we can see that there remain serious challenges to the future of pilot community forestry REDD+ projects,including the complex interaction between the multinational actors and the local socio-ecological *** move forwards, this study

关键词： REDD+ Governance quality Indicator Q-Methodology Deforestation Cambodia

Effects of three consecutive monthly intravitreal injection of ranibizumab for polypoidal choroidal vasculopathy in Korea

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International Journal of Ophthalmology(English edition) 2015年第2期8卷 315-320页

作者： young Gun Park seungbum Kang young Jung Roh Department of Ophthalmology College of Medicine The Catholic University of Korea Yeouido St. Mary's Hospital Department of Ophthalmology The Catholic University of Korea Daejeon St. Mary's Hospital

AIM: To evaluate the efficacy and safety of three consecutive monthly injections of intravitreal ranibizumab for the treatment of polypoidal choroidal vasculopathy(PCV) in ***: A retrospective chart review of 25 patients(27 eyes) with PCV was conducted. Patients received three initial monthly intravitreal injections(0.5 mg) of ranibizumab and were monitored monthly for 12 mo from January 2010 to October 2011. Reinjection of ranibizumab after three initial monthly loading was administered on an as-needed basis, guided by the optical coherence tomography(OCT), fluorescein angiography(FA) and indocyanine green angiography(ICGA). The main outcomes were the changes of the mean best corrected snellen visual acuity(VA), central macular thickness(CMT) by OCT, the changes of polyps and branching vascular network by FA and ICGA, and total number of injections received by patients during the 12 ***: The mean best corrected snellen visual acuities at baseline, 1, 3, 6 and 12 mo after primary injection were 0.77 ±0.59, 0.76 ±0.53, 0.70 ±0.47, 0.63 ±0.43,0.61 ±0.43, 0.62 ±0.42 log MAR, respectively, and showed significant improvement at 3, 6, 12mo(P =0.003, P =0.002,P =0.018, Wilcoxon signed-rank test). The mean CMT at baseline, 1, 2, 3, 6, and 12 mo was 312.41 ±66.38 μm,244.59 ±71.47 μm, 232.32 ±69.41 μm, 226.69 ±69.03 μm,228.62 ±37.07 μm, 227.59 ±51.01 μm respectively, and showed significant reduction(all P signed-rank test). Polypoidal lesions resolved on ICGA in 3 eyes(11.1%) and a branching vascular network remained in all 24 eyes(88.9%). A total of 106 injections were given in the 12-month period, which equaled to a mean of 3.92(range, 3-6) times. sixteen of the 27 treatedeyes had additional 1.56 ±0.91 injections. The others(11eyes) had just 3 consecutive ***: An initial loading dose of three monthly ranibizumab injections is a safe and effective method in treating PCV, with visual and anatomical improvement over one ye

关键词： ranibizumab polypoidal choroidal vasculopathy intravitral injection

Development of genome engineering technologies in cattle: from random to specific

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Journal of Animal science and Biotechnology 2018年第2期9卷 285-293页

作者： soo-young Yum Ki-young Youn Woo-Jae Choi Goo Jang Department of Veterinary Clinical science College of Veterinary Medicine and the Research Institute of Veterinary Science Seoul National University Farm Animal Clinical Training and Research Center Institute of Green Bio Science Technology Seoul National University Emergence Center for Food-Medicine Personalized Therapy system Advanced Institutes of Convergence Technology Seoul National University College of Veterinary Medicine Seoul National University

The production of transgenic farm animals(e.g., cattle) via genome engineering for the gain or loss of gene functions is an important undertaking. In the initial stages of genome engineering, DNA micro-injection into one-cell stage embryos(zygotes) followed by embryo transfer into a recipient was performed because of the ease of the ***, as this approach resulted in severe mosaicism and has a low efficiency, it is not typically employed in the cattle as priority, unlike in mice. To overcome the above issue with micro-injection in cattle, somatic cell nuclear transfer(sCNT) was introduced and successfully used to produce cloned livestock. The application of sCNT for the production of transgenic livestock represents a significant advancement, but its development speed is relatively slow because of abnormal reprogramming and low gene targeting efficiency. Recent genome editing technologies(e.g.,ZFN, TALEN, and CRIsPR-Cas9) have been rapidly adapted for applications in cattle and great results have been achieved in several fields such as disease models and bioreactors. In the future, genome engineering technologies wil accelerate our understanding of genetic traits in bovine and wil be readily adapted for bio-medical applications in cattle.

关键词： Cattle CRIsPR-Cas9 Genome engineering technologies Transgenesis Transposon