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Whether arc mantle is more oxidized than oceanic mantle is persistently debated. The behavior of multivalent vanadium (V) is oxygen fugacity (fO 2 ) sensitive, and the ratios of V to a homovalent element (e.g., Sc, Ti, or Yb) in basalts were commonly used as fO 2 proxies. Similar ratios, such as V/Sc, between arc basalts and mid-ocean ridge basalts were previously taken as evidence for similar fO 2 s in their mantle sources. However, this claim may be problematic because elemental ratios are primarily controlled by partition coefficients (D values), which are further affected by various factors. Here we determined D values of V and other transition elements between mantle minerals and basaltic melts at typical arc T-P-H 2 O conditions and variable fO 2 s. Combining experimental results with published data, the effects of fO 2 , T, P, and phase compositions on D V , D Sc , and D Ti for olivine, orthopyroxene (opx), clinopyroxene (cpx), and spinel were evaluated using multiple linear regressions. The results show that D V values for these four minerals all increase with decreasing fO 2 and temperature, leading to higher D V /D Sc and D V /D Ti ratios at low temperatures than those at high temperatures given a certain fO 2 . Thus, similar V/Sc and V/Ti ratios between arc basalts and mid-ocean ridge basalts reflect a relatively oxidized arc mantle due to its lower melting temperatures. In light of the highly incompatible behavior of Ti during mantle melting, V-Ti systematics are regarded to be more superior than V-Sc systematics in the fO 2 estimation. Partial melting modelling results using V-Ti systematics reveal that arc mantle is, on average,~0.9 log units higher in fO 2 than oceanic mantle.Plain Language Summary The oxidation state of the Earth`s mantle, often expressed as oxygen fugacity (fO 2 ), could control the behavior of multivalent elements and thus exert a significant influence on the formation of magmatic ore deposits and the secular evolution of Earth`s atmosphere. Whether arc mantle is more oxidized than oceanic mantle remains a controversial topic. As a multivalent element, partitioning behavior of vanadium is fO 2 sensitive and is capable of tracking mantle redox state. However, except fO 2 , other factors (temperature, pressure, and phase composition) that may affect vanadium partitioning behavior have not been clearly evaluated. Here we conducted high temperature and pressure experiments to determine partition coefficients of vanadium during mantle melting under various fO 2 conditions. Combining our and published data, we evaluated the effects of fO 2 , T, P, and compositions of mineral and melt on the vanadium partitioning using multiple linear regressions. The results indicate that, in addition to fO 2 , temperature exerts a significant control on the vanadium partitioning. Additionally, we estimated fO 2 of the arc mantle via numerical modelling using appropriate partition coefficients for vanadium. Our results clarify and reconcile the discrepancies between previous studies and reveal that a...

Electrostatic gating field and light illumination are two widely used stimuli for semiconductor devices. Via capacitive effect, a gate field modifies the carrier density of the devices, while illumination generates extra carriers by exciting trapped electrons. Here we report an unusual illumination-enhanced gating effect in a two-dimensional electron gas at the LaAlO 3 /SrTiO 3 interface, which has been the focus of emergent phenomena exploration. We find that light illumination decreases, rather than increases, the carrier density of the gas when the interface is negatively gated through the SrTiO 3 layer, and the density drop can be 20 times as large as that caused by the conventional capacitive effect. This effect is further found to stem from an illumination-accelerated interface polarization, an originally extremely slow process. This unusual effect provides a promising controlling of the correlated oxide electronics in which a much larger gating capacity is demanding due to their intrinsic larger carrier density.

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The Indian muntjac (Muntiacus muntjak vaginalis) has a karyotype of 2n=6 in the female and 7 in the male, the karyotypic evolution of which through extensive tandem fusions and several centric fusions has been well-documented by recent molecular cytogenetic studies. In an attempt to define the fusion orientations of conserved chromosomal segments and the molecular mechanisms underlying the tandem fusions, we have constructed a highly redundant (more than six times of whole genome coverage) bacterial artificial chromosome (BAC) library of Indian muntjac. The BAC library contains 124,800 clones with no chromosome bias and has an average insert DNA size of 120 kb. A total of 223 clones have been mapped by fluorescent in situ hybridization onto the chromosomes of both Indian muntjac and Chinese muntjac and a high-resolution comparative map has been established. Our mapping results demonstrate that all tandem fusions that occurred during the evolution of Indian muntjac karyotype from the acrocentric 2n=70 hypothetical ancestral karyotype are centromere-telomere (head-tail) fusions.

Key-words:Chishui River, fish distribution, environmental variables, canonical correspondence analysis (CCA) , fish conservationThis study aimed to characterize fish assemblage and evaluate environmental influence on fish distribution in the Chishui River, a protected tributary of the upper Yangtze River. Thirty-one sites regularly distributed in longitudinal profiles were sampled in April, 2007. Sixty-two fish species belonging to 3 orders, 8 families, and 52 genera were collected. Species richness and diversity significantly increased from upstream to downstream. Canonical correspondence analysis (CCA) highlighted five environmental variables (altitude, conductivity, dissolved oxygen, channel width and current velocity) significantly structuring fish assemblages in the Chishui River. Based on species distributions and fish-habitat relationships, conservation strategies were proposed for different reaches. RÉSUMÉStructure des communautés piscicoles de la rivière Chishui, un affluent protégé du fleuve Yangtzé Cette étude caractérise les communautés de poissons et évalue l'influence environnementale sur la distribution piscicole dans la rivière Chishui, un affluent protégé du fleuve Yangtzé. Trente-et-un sites régulièrement répartis sur le profil longitudinal ont été échantillonnés en avril 2007. Soixante-six espèces de poissons appartenant à 3 ordres, 8 familles et 52 genres ont été collectées. La richesse et la diversité spécifique augmentent significativement de l'amont vers l'aval. L'analyse canonique des correspondances (CCA) identifie cinq variables environnementales (altitude, conductivité, oxygène dissous, largeur du lit et vitesse du courant), structurant significativement les communautés de poissons dans la rivière Chishui. À partir des distributions spécifiques et des relations habitat-poisson, des straté-gies de conservation sont proposées pour les différents biefs. Mots-clés :(1) Institute of Hydrobiology, Chinese Academy of Sciences, 7th southern road of East Lake,

We here report an identification of SDSS J141324+530527.0 (SBS 1411+533) at z = 0.456344 as a new "changinglook" quasar with a "turn-on" spectral type transition from Type-1.9/2 to Type-1 within a rest frame time scale of 1-10 yr by a comparison of our new spectroscopic observation and the Sloan Digital Sky Survey (SDSS) archive data base. The SDSS DR7 spectrum taken in 2003 is dominated by a starlight emission from host galaxies redward of the Balmer limit, and has non-detectable broad Hβ line. The new spectrum taken by us on June 1st, 2017 and SDSS DR14 spectrum taken on May 29, 2017 indicate that the object is of a typical quasar spectrum with a blue continuum and strong Balmer broad emission lines. In addition, an intermediate spectral type can be identified in the SDSS DR13 spectrum taken in 2015. The invariability of the line wing of Mg IIλ2800 emission and time scale argument (The invariability of [O III]λ5007 line blue asymmetry) suggests that a variation of obscuration (an accelerating outflow) is not a favorable scenario. The time scale argument allows us to believe the type transition is possibly caused by either a viscous radial inflow or a disk instability around a ∼ 5 − 9 × 10 7 M ⊙ black hole.

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