Diversity of greenhouse gas emission drivers across European countries since the 2008 crisis     

Quentin Perrier  Céline Guivarch  Olivier Boucher 《Climate Policy》2019,19(9):1067-1087

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A Non-Homogeneous Model for Kriging Dosimetric Data     

Lajaunie  Christian  Renard  Didier  Quentin  Alexis  Le Guen  Vincent  Caffari  Yvan 《Mathematical Geosciences》2020,52(7):847-863

Mathematical Geosciences - This paper deals with kriging-based interpolation of dosimetric data. Such data typically show some inhomogeneities that are difficult to take into account by means of...  相似文献   

Large-scale structure of galaxies in the Ophiuchus region     

Takashi Hasegawa  †  Ken-ichi Wakamatsu  ‡  Matthew Malkan  ‡  Kazuhiro Sekiguchi  John W. Menzies  Quentin A. Parker  Jun Jugaku  Hiroshi Karoji  Sadanori Okamura 《Monthly notices of the Royal Astronomical Society》2000,316(2):326-344

The large-scale structure around the Ophiuchus cluster of galaxies in the vicinity of the Galactic Centre ( l =05, b =95, cz =8500 km s⁻¹) is investigated on the basis of a galaxy survey and spectroscopic observations made for a 12°×17° area. The galaxy survey was performed using six ESO/SERC Sky Survey Atlas films, and 4021 galaxies were detected in total. Recession velocities were newly obtained for 179 galaxies to make the total number of galaxies in the survey area with known velocities 219.
In the distribution of bright galaxies, we identified seven new clumps of galaxies. Comparing the surface number density of bright galaxies with the Galactic extinction, which is estimated from the 100‐μm flux density in the IRAS Sky Survey Atlas, we demonstrate that the seven clumps are not spurious as a result of the inhomogeneity of the Galactic extinction. Among the seven clumps, two are found to be clusters and four to be groups on the basis of the histogram of recession velocities and the number of member galaxies. The Ophiuchus cluster, two newly identified clusters, and four groups are all concentrated at 9000 km s⁻¹. Field galaxies are also distributed centred at 8500 km s⁻¹. Hence field galaxies occupy a common three-dimensional region with galaxies in the clusters and groups, and altogether they form a large-scale structure of supercluster size. As opposed to the overdensity in the supercluster region, the mean number density of galaxies in the velocity range 0–5000 km s⁻¹ is only 25 per cent of the mean number density of the Universe, comparable with the density of the well-known Böotes void. Hence this nearby three-dimensional region in Ophiuchus is a void of galaxies also.  相似文献   

Structural controls on mechanical compaction within sandstones: An example from the Apsheron Peninsula,Azerbaijan     

Christine Souque  Quentin J. Fisher  Martin Casey  Peter Bentham 《Marine and Petroleum Geology》2010

Mechanical compaction of sand-rich reservoirs usually occurs during shallow burial and involves the rearrangement of framework grains and the ductile deformation of soft lithoclasts. The reservoir quality (porosity and permeability) of some Neogene sandstones of the South Caspian Basin has, however, been dramatically reduced by mechanical compaction involving extensive grain-fracturing (i.e. porosity collapse). These sandstones were probably susceptible to pervasive grain-fracturing because they were buried rapidly and experienced compressional deformation prior to reaching 80 °C. Consequently, they did not undergo quartz cementation and were therefore exposed to high stresses while they were extremely weak. Grain-size and structural position are also important controls on the distribution of grain fracturing in the onshore analogue in the Apsheron Peninsula. Microstructural analysis confirms that susceptibility to distributed grain-fracturing increases with increasing grain-size. Structural position has also an important impact on the distribution of porosity collapse. In particular, sandstones within the hinges of folded sections have undergone much more extensive grain-fracturing than within the surrounding area; the increased stresses in this structural position have enhanced distributed grain-fracturing and subsequent deformation band development.  相似文献   

HgO at high pressures: the transition to the NaCl structure (HgO-III) and the equation of state of tetragonal HgO-II     

Jinyuan Yan  Bin Chen  Selva Vennila Raju  Budhiram K. Godwal  Alastair A. MacDowell  Jason Knight  Hongwei Ma  Quentin Williams 《Physics and Chemistry of Minerals》2012,39(4):269-275

The high-pressure behavior of HgO-montroydite was investigated up to 36.5 GPa using angle-dispersive X-ray diffraction. The tetragonal phase of this material (HgO-II), a distortion of the NaCl structure, transforms into the cubic NaCl structure (HgO-III) above ~31.5 GPa. The transformation of mercury oxide from the orthorhombic Pnma (HgO-I) structure to a tetragonal I4/mmm structure (HgO-II) is confirmed to occur at 13.5 ± 1.5 GPa. Neither of the high-pressure phases, HgO-II nor HgO-III, is quenchable in pressure. The derived isothermal bulk modulus of HgO-II and its pressure derivative strongly depend on the assumed zero-pressure volume of this phase, but our elasticity results on HgO-II nevertheless lie significantly closer to theoretical calculations than prior experimental results, and the measured pressure of the phase transformation to the NaCl structure is also in agreement with recent theoretical results. The general accord with theory supports the existence of significant relativistic effects on the high-pressure phase transitions of HgO.  相似文献   

The Witputs diamictite in southern Namibia and associated rocks: constraints for a global glaciation?     

Udo Zimmermann  Jennifer Tait  Quentin G. Crowley  Vanessa Pashley  Gijs Straathof 《International Journal of Earth Sciences》2011,100(2-3):511-526

The Witputs section of the Gariep Belt (S Namibia) comprises a sequence of clastic and chemical sediments, which have been interpreted as representative of a Late Neoproterozoic global or near-global ice age event, and recent biostratigraphic work in the upper rocks of the Witputs suggest a Late Ediacaran age. To further characterise this sequence and provide additional age constraints, a detailed sedimentological and detrital zircon study has been carried out. The petrographic, sedimentological and geochemical characteristics of the Witputs diamictite determined in this study are homogenous and indicative of debris flow or palaeo-valley infill sediments, deposited in an oxic environment with no glaciogenic evidence. This homogeneity is also reflected in the detrital zircon age spectra with most ages falling between 1.0 and 1.3?Ga, representing the local geology, with the youngest grain at 1030.2?±?10.9 (2??) (n?=?92?<10% discordance), despite the fact that mid and Late Neoproterozoic volcanic activity is known in the local region. The overlying carbonate rocks, often considered to be ??cap carbonates??, show high Mn (up to 60% MnO), with base metal precipitation (Zn, V, Co), and are recrystallised. Their ??¹³C_VPDB isotope ratios are homogeneous at around-3. Major and trace element ratios reach values which indicate that C?CO isotopes may be disturbed and might not reflect primary global seawater composition, thus questioning their use for global correlation and comparison with composite chemostratigraphic curves. The contact to the overlying Late Ediacaran Sanddrif Member is not exposed, and the rocks dip in a different direction than the underlying carbonate rocks. The c. 40-m-thick section is characterised by rapid lithology changes including shales, calcareous sandstones and wackes, fine-grained conglomerates and rare clean quartz-rich sandstones, all of which have strikingly similar detrital zircon populations, and the youngest zircon is dated at 1082.8?±?10?Ma (2?? errors, from 72 grains with <10% discordance). Acritarchs earlier found in the Sanddrif Member, however, indicate a post-570?Ma depositional age. If the diamictites are glacio-marine deposits, then an interesting conclusion is that the clastic sediments can display a very immature geochemical signature, indicating a localised provenance, with derivation purely from the local basement rocks, which is also reflected in the detrital zircon populations. However, we would hesitate to assign a glacial origin to the deposits as no glacial indicators, other than a diamictitic texture, were observed. Clearly, far more work on the detailed mapping and sedimentology of the Neoproterozoic Gariep Belt deposits is required, particularly as many are currently used for global correlation. Age constraints derived from extensive detrital zircon work can only constrain the deposits as being post 1.03?Ma with the detritus being purely locally derived.  相似文献   

The AAO/UKST SuperCOSMOS Hα survey     

Quentin A. Parker  S. Phillipps  M. J. Pierce  M. Hartley  N. C. Hambly  M. A. Read  H. T. MacGillivray  S. B. Tritton  C. P. Cass  R. D. Cannon  M. Cohen  J. E. Drew  D. J. Frew  E. Hopewell  S. Mader  D. F. Malin  M. R. W. Masheder  D. H. Morgan  R. A. H. Morris  D. Russeil  K. S. Russell  R. N. F. Walker 《Monthly notices of the Royal Astronomical Society》2005,362(2):689-710

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A circular planetary nebula around the OH/IR star OH 354.88−0.54 (V1018 Sco)     

Martin Cohen  Quentin A. Parker  Jessica Chapman 《Monthly notices of the Royal Astronomical Society》2005,357(4):1189-1196

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Two new evolved bipolar planetary nebulae in the solar neighbourhood     

David J. Frew †  Quentin A. Parker  Delphine Russeil 《Monthly notices of the Royal Astronomical Society》2006,372(3):1081-1092

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A new population of planetary nebulae discovered in the Large Magellanic Cloud – I. Preliminary sample     

Warren. A. Reid  Quentin A. Parker 《Monthly notices of the Royal Astronomical Society》2006,365(2):401-413

We report our initial discovery of 73 new planetary nebulae (PNe) in the Large Magellanic Cloud (LMC) following confirmatory 2dF spectroscopy on the Anglo-Australian Telescope. Preliminary candidate sources come from a 10 per cent sub-area of our new deep, high-resolution Hα map of the central 25 deg² of the LMC obtained with the UK Schmidt Telescope. The depth of the high-resolution map was extended to   R _equiv∼ 22  for  Hα (4.5 × 10⁻¹⁷ erg cm⁻² s⁻¹Å⁻¹)  by a process of multi-exposure median co-addition of a dozen 2-h Hα exposures. The resulting map is at least 1-mag deeper than the best wide-field narrow-band LMC images currently available. This depth, combined with our selection technique, has also led to the discovery of extended asymptotic giant branch (AGB) haloes around many new and previously known LMC PNe for the first time. Once complete, our new survey is expected to triple the LMC PN population and have significant implications for the LMC PN luminosity function, kinematics, abundance gradients, chemical evolution and, via study of the AGB haloes, the initial to final mass relation for low- to intermediate-mass stars.  相似文献