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Primordial magnetic fields from gravitationally coupled electrodynamics in nonsingular bounce cosmology

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Science China(Physics,Mechanics & Astronomy) 2018年第10期61卷 43-50页

作者： JieWen Chen ChongHuan Li YuBin Li mian Zhu CAS Key Laboratory for Researches in Galaxies and Cosmology Department of AstronomyUniversity of Science and Technology of China School of Astronomy and Space Science University of Science and Technology of China Department of Physics and Astronomy University of Utah Department of Physics The Chinese University of Hong Kong School for Gifted Young University of Science and Technology of China

We in this paper study a class of mechanism of the production of the primordial magnetic field(PMF) in the non-singular bouncing cosmology, through the coupling of the electromagnetic field to gravity. We adopt an electrodynamic model with a coupling coefficient as a function of the scale factor a, i.e., f = 1 +(a/a?)^(-n), with a? and n > 0 being constants. With analytical calculations, we find that this model can yield a blue tilted power spectrum of PMF on large scales from 1 Mpc to the Hubble length if the bounce scenario has experienced a contracting phase with an equation-of-state parameter larger than-1/3. Furthermore, in order to satisfy the constraints of observational data, the present mechanism favors the so-called ekpyrotic-bounce paradigm. The back-reaction of the energy density of PMF at the bouncing point can lead to additional theoretical constraints on the underlying bouncing paradigm.

关键词： primordial magnetic field bounce cosmology gravitationally coupled electrodynamics

Provenance and drainage system of the Early Cretaceous volcanic detritus in the Himalaya as constrained by detrital zircon geochronology

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Journal of Palaeogeography 2015年第1期4卷 85-98页

作者： Xiu-mian Hu Eduardo Garzanti Wei An State Key Laboratory of Mineral Deposits Research School of Earth Sciences and Engineering Nanjing University Department of Earth and Environmental Sciences Università di Milano?BicoccaMilano 20126 Italy

The age range of the major intra-plate volcanic event that affected the northern Indian margin in the Early Cretaceous is here defined precisely by detrital zircon geochronology. U-Pb ages of Early Cretaceous detrital zircons found in the Cretaceous to the Paleocene sandstones cluster mainly between 142 Ma and 123 Ma in the northern Tethys Himalayan unit, and between 140 Ma and 116 Ma in the southern Tethys Himalayan unit. The youngest and oldest detrital zircons within this group indicate that volcanism in the source areas started in the latest Jurassic and ended by the early Albian. Stratigraphic data indicate that volcaniclastic sedimentation began significantly earlier in southern Tibet （Tithonian） than in Nepal （Valangin- ian）, and considerably later in Spiti and Zanskar （Aptian/AIbian） to the west. This apparent westward migration of magmatism was explained with progressive westward propagation of extensional/transtensional tectonic activity and development of fractures cutting deeply across the Indian continental margin crust. However, detrital zircon geochronology provides no indication of heterochroneity in magmatic activity in the source areas from east to west, and thus lends little support to such a scenario. Westward migration of volcaniclastic sedimentation may thus reflect instead the westward progradation of major drainage systems supplying volcanic detritus sourced from the same volcanic centers in the east. Development of multiple radial drainage away from the domal surface uplift associated with magmatic upwelling, as observed for most large igneous provinces around the world, may also explain why U-Pb ages of detrital zircons tend to cluster around 133-132 Ma （the age of the Cornel igneous province） in Tethys Himalayan units, but around 118-117 Ma （the age of the Rajmahal igneous province） in Lesser Himalayan units.

关键词： northern Indian margin Cretaceous Himalayan Orogen volcaniclastic detri-tus drainage system zircon geochronology palaeogeography

Statistical inference for the nonparametric and semiparametric hidden Markov model via the composite likelihood approach

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Science China Mathematics 2023年第3期66卷 601-626页

作者： mian Huang Yue Huang Weixin Yao School of Statistics and Management Shanghai University of Finance and EconomicsShanghai 200433China Department of Statistics University of CaliforniaRiversideRiversideCA 92521USA

In this paper, we propose a new estimation method for a nonparametric hidden Markov model(HMM), in which both the emission model and the transition matrix are nonparametric, and a semiparametric HMM, in which the transition matrix is parametric while emission models are nonparametric. The estimation is based on a novel composite likelihood method, where the pairs of consecutive observations are treated as independent bivariate random variables. Therefore, the model is transformed into a mixture model, and a modified expectation-maximization(EM) algorithm is developed to compute the maximum composite *** systematically study asymptotic properties for both the nonparametric HMM and the semiparametric HMM. We also propose a generalized likelihood ratio test to choose between the nonparametric HMM and the semiparametric HMM. We derive the asymptotic distribution and prove the Wilk’s phenomenon of the proposed test statistics. Simulation studies and an application in volatility clustering analysis of the volatility index in the Chicago Board Options Exchange(CBOE) are conducted to demonstrate the effectiveness of the proposed methods.

关键词： nonparametric HMM nonhomogeneous HMM semiparametric estimate composite likelihood generalized likelihood ratio test

A new free-living marine nematode species of Rhinema from the South China Sea

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Journal of Oceanology and Limnology 2020年第2期38卷 545-549页

作者： ZHAI Hongxiu HUANG mian HUANG Yong College of Life Sciences Liaocheng UniversityLiaocheng 252059China Department of Marine Organism Taxonomy and Phylogeny Institute of OceanologyChinese Academy of SciencesQingdao 266071China University of Chinese Academy of Sciences Beijing 100049China

A new free-living marine nematode species of the genus Rhinema belonging to the family Monoposthiidae was collected from marine sediments in the Qiongzhou Strait of the South China Sea,and it is described here as Rhinema longispicula *** new species is characterized by coarsely annulated cuticle with 12 longitudinal ridges(alae)marked as reversed *** first and second annuli broader and form a kind of a cephalic *** amphideal fovea circular,situated in the middle of the broad second annulus,not surrounded by dense *** cavity cylindrical with a large dorsal *** with a prominent anterior pharyngeal bulb and an elongated terminal *** spicules strongly curved,with cephalated proximal end and pointed distal *** boat-shaped,without apophysis.A long and blunt precloacal seta *** with two opposed,outstretched ovaries.

关键词： Rhinema longispicula sp.nov. free-living marine nematode taxonomy

Regulation of the pentose phosphate pathway in cancer

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Protein & Cell 2014年第8期5卷 592-602页

作者： Peng Jiang Wenjing Du mian Wu School of Life Sciences Tsinghua University Beijing 100084 China Hefei National Laboratory for Physical Sciences at Microscale School of Life Sciences University of Science and Technology of China Hefei Anhui 230027 China Department of Cancer Biology Perelman School of Medicine Abramson Family Cancer Research Institute University of Pennsylvania Philadelphia PA 19104 USA

Energy metabolism is significantly reprogrammed in many human cancers, and these alterations confer many advantages to cancer cells, including the pro- motion of biosynthesis, ATP generation, detoxification and support of rapid proliferation. The pentose phos- phate pathway （PPP） is a major pathway for glucose catabolism. The PPP directs glucose flux to its oxi- dative branch and produces a reduced form of nico- tinamide adenine dinucleotide phosphate （NADPH）, an essential reductant in anabolic processes. It has become clear that the PPP plays a critical role in regulating cancer cell growth by supplying cells with not only ribose-5-phosphate but also NADPH for detoxification of intracellular reactive oxygen species, reductive biosynthesis and ribose biogenesis. Thus, alteration of the PPP contributes directly to cell pro- liferation, survival and senescence. Furthermore, recent studies have shown that the PPP is regulated oncogenically and/or metabolically by numerous fac- tors, including tumor suppressors, oncoproteins and intracellular metabolites. Dysregulation of PPP flux dramatically impacts cancer growth and survival. Therefore, a better understanding of how the PPP is reprogrammed and the mechanism underlying the balance between glycolysis and PPP flux in cancer will be valuable in developing therapeutic strategies targeting this pathway.

关键词： pentose phosphate pathway (PPP)G6PD NADPH glucose metabolism cancer cellproliferation

Community attitudes toward ecotourism development and environmental conservation in nature reserve:a case of Fujian Wuyishan National Nature Reserve,China

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Journal of Mountain Science 2017年第7期14卷 1405-1418页

作者： CHEN Bi-xia QIU Zhen-mian Faculty of Agriculture University of the RyukyusNishihara Town School of Economics Fujian Normal University Kanazawa University

Using social exchange theory, this study investigated residents＇ attitudes toward the preliminary stage of tourism development in nature reserves in Wuyishan National Nature Reserve of China, and the socio-economic and negative effects of residents＇ attitude toward the tourist industry. Results of the questionnaire survey indicated that local people perceived they could benefit from the economic activities related to tourism, and were supportive of the conservation of natural resources and local culture, sustainable community development, and community participation in ecotourism planning and management. This study also revealed that the variables of age, gender, education level, household income, family size, non-farm work arrangements, and the distance to tourism attractions, have significant association with respondents＇ attitudes toward ecotourism development, or negative impacts of the tourist industry. Respondents who are male, or have a higher household income, are more supportive of tourism development inside the reserve. Younger and more highly educated community members are more likely to support learning more about natural and cultural resources and landscapes. Respondents who have a hieher household income, or live far fromthe village center, are more concerned about the negative environmental impacts of tourism development.

关键词： Economic benefits Environmentalconservation Nature reserve Residents' attitude Tourism development Wuyishan National NatureReserve

Flow dynamics analyses of pathophysiological liver lobules using porous media theory

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Acta Mechanica Sinica 2017年第4期33卷 823-832页

作者： Jinrong Hu Shouqin Lü Shiliang Feng mian Long Center of Biomechanics and Bioengineering Key Laboratory of Microgravity (National Microgravity Laboratory) Beijing Key Laboratory of Engineered Construction and Mechanobiology Institute of Mechanics Chinese Academy of Sciences School of Engineering Science University of Chinese Academy of Sciences

Blood flow inside the liver plays a key role in hepatic functions, and abnormal hemodynamics are highly correlated with liver diseases. To date, the flow field in an elementary building block of the organ, the liver lobule,is difficult to determine experimentally in humans due to its complicated structure, with radially branched microvasculature and the technical difficulties that derive from its geometric constraints. Here we established a set of 3D computational models for a liver lobule using porous media theory and analyzed its flow dynamics in normal, fibrotic,and cirrhotic lobules. Our simulations indicated that those approximations of ordinary flow in portal tracts（PTs） and the central vein, and of porous media flow in the sinusoidal network, were reasonable only for normal or fibrotic *** modified with high resistance in PTs and collateral vessels inside sinusoids were able to describe the flow features in cirrhotic lobules. Pressures, average velocities, and volume flow rates were profiled and the predictions compared well with experimental data. This study furthered our understanding of the flow dynamics features of liver lobules and the differences among normal, fibrotic, and cirrhotic lobules.

关键词： porous cirrhotic collateral ordinary permeability tracts constraints branched porosity inlet

Influence of relative phase on the nonsequential double ionization process of CO_(2) molecules by counter-rotating two-color circularly polarized laser fields

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Communications in Theoretical Physics 2021年第7期73卷 121-126页

作者： mian Peng Li-Hua Bai Zhen Guo Department of Physics College of SciencesShanghai UniversityShanghai 200444China

We investigate the nonsequential double ionization(NSDI) of linear triatomic molecules by the counter-rotating two-color circularly polarized(CRTC) laser fields with a classical ensemble method. The results of the simulation reveal that NSDI yield strongly connected with the relative phase. The trajectory tracking method shows that the return time of the electron is controlled by the relative phase. In addition, when we change the CRTC laser wavelengths, the relative phase of the maximum and minimum yield of NSDI also changes. This shows that the influence of the Coulomb potential in the triatomic molecules on the electron return process cannot be ignored. This work will effectively promote the electronic dynamics study of NSDI for the triatomic molecule.

关键词： linear triatomic molecules relative phase two-color laser fields nonsequential double ionization

Displacement of peritoneal end of a shunt tube to pleural cavity: A case report

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World Journal of Clinical Cases 2020年第19期8卷 4676-4680页

作者： Jie Liu mian Guo Department of Neurosurgery The Second Affiliated Hospital of Harbin Medical UniversityHarbin 150086Heilongjiang ProvinceChina

BACKGROUND The common treatment for hydrocephalus is insertion of a ventriculoperitoneal *** tube displacement is one of the common *** shunt tube displacements occur in children and has a reportedly lower incidence in *** SUMMARY This study reports an adult patient(male,56 years)who suffered from intracranial aneurysm and subarachnoid hemorrhage and underwent aneurysm clipping following *** month post onset of the disease,the patient underwent ventriculoperitoneal shunt due to *** peritoneal end of the shunt tube was displaced in the peritoneal cavity 9 years after the aneurysm *** peritoneal end of the shunt tube was removed and ventriculoperitoneal shunt was re-performed after anti-inflammatory *** Shunt tube displacement has a low incidence in *** order to avoid shunt tube displacement,there is a need to summarize its causative factors and practice personalized medicine.

关键词： Ventriculoperitoneal shunt Hydrocephalus Shunt tube displacement Pleural cavity Intracranial aneurysm Case report Subarachnoid hemorrhage