Dust-Gas Interrelations In Comets: Observations And Theory     

Combi  Michael R.  KABIN  KONSTANTIN  DeZEEUW  Darren L.  Gombosi  Tamas I.  Powell  Kenneth G. 《Earth, Moon, and Planets》1997,79(1-3):275-306

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The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe   总被引：1，自引：0，他引：1  

Ed Hawkins  Steve Maddox  Shaun Cole  Ofer Lahav  Darren S. Madgwick  Peder Norberg  John A. Peacock  Ivan K. Baldry  Carlton M. Baugh  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Carole Jackson  Bryn Jones  Ian Lewis  Stuart Lumsden  Will Percival  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2003,346(1):78-96

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The Measurement of the Orientation of the Magnetic Field in Molecular Clouds     

Martin Houde  Ruisheng Peng  Hiroshige Yoshida  Roger H. Hildebrand  Thomas G. Phillips  C. Darren Dowell  Pierre Bastien  Jessie L. Dotson  John E. Vaillancourt 《Astrophysics and Space Science》2004,292(1-4):127-134

We discuss how the combination of polarimetry and ion-to-neutral molecular line width ratio measurements permits the determination of the magnitude and orientation of the magnetic field in the weakly ionized parts of molecular clouds. Polarimetry measurements give the field orientation in the plane of the sky and the ion-to-neutral molecular line width ratio determines the angle between the magnetic field and the line of sight. We show the first results obtained with this technique on the M17 and Orion A star-forming region using Hertz 350 μm polarimetry maps and HCO⁺-to-HCN molecular line width ratios to provide the first view of the spatial orientation of the magnetic field these molecular clouds.  相似文献   

Do agonistic behaviours bias baited remote underwater video surveys of fish?          下载免费PDF全文

Katherine M. Dunlop  E. Marian Scott  Darren Parsons  David M. Bailey 《Marine Ecology》2015,36(3):810-818

Marine environments require monitoring to determine the effects of impacts such as climate change, coastal development and pollution and also to assess the effectiveness of conservation measures. Marine protected areas (MPAs) are being established globally and require periodic monitoring to determine whether their objectives are being met. Baited underwater video systems are becoming a popular method for monitoring change within protected fish populations, because they are less damaging to habitats than bottom trawling and allow for more statistical powerful comparisons to determine spatial and temporal patterns in the relative abundances, lengths and biomass of demersal and pelagic fishes. However, much remains uncertain about how interactions between the fish and bait and between the fish themselves affect the results obtained. Agonistic behaviours are frequently observed around the bait of the camera and potentially bias fish density estimates by altering the number and size classes seen at cameras. Here we counted the number of agonistic behaviours between pink snappers (Pagrus auratus), the size of fish involved and whether the fish left the field of view following such behaviours. The study consisted of 20 baited underwater video deployments inside a New Zealand marine reserve and 20 in adjacent open areas. We observed a significant relationship between the peak number of fish observed at the camera and the total number of agonistic behaviours, as well as the number of both aggressor and subordinate fish leaving the camera field of view following interactions. The slope of the latter relationship and thus the absolute numbers of fish leaving were higher for subordinate fish. As subordinates were significantly smaller than aggressors, the apparent size frequency distribution is likely skewed away from smaller size classes. The staying time of the fish and thus the maximum number of fish present at the camera will be reduced by agonistic behaviours and the absolute magnitude of this effect appears to be greater at high fish densities. Our results suggest that an overall effect of these phenomena is to underestimate the differences in abundance between MPAs and open areas, but also to overestimate differences in average size.  相似文献   

The 2dF Galaxy Redshift Survey: stochastic relative biasing between galaxy populations     

Vivienne Wild  John A. Peacock  Ofer Lahav  Edward Conway  Steve Maddox  Ivan K. Baldry  Carlton M. Baugh  Joss Bland-Hawthorn  Terry Bridges  Russell Cannon  Shaun Cole  Matthew Colless  Chris Collins  Warrick Couch  Gavin Dalton  Roberto De Propris  Simon P. Driver  George Efstathiou  Richard S. Ellis  Carlos S. Frenk  Karl Glazebrook  Carole Jackson  Ian Lewis  Stuart Lumsden  Darren Madgwick  Peder Norberg  Bruce A. Peterson  Will Sutherland  Keith Taylor 《Monthly notices of the Royal Astronomical Society》2005,356(1):247-269

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Halo assembly bias and its effects on galaxy clustering     

Darren J. Croton  Liang Gao  Simon D. M. White 《Monthly notices of the Royal Astronomical Society》2007,374(4):1303-1309

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Observing cosmic microwave background polarization through ice     

Luca Pietranera  Stefan A. Buehler  Paolo G. Calisse  Claudia Emde  Darren Hayton  Viju Oommen John  Bruno Maffei  Lucio Piccirillo  Giampaolo Pisano  Giorgio Savini  T. R. Sreerekha 《Monthly notices of the Royal Astronomical Society》2007,376(2):645-650

Ice crystal clouds in the upper troposphere can generate polarization signals at the μK level. This signal can seriously affect very sensitive ground-based searches for E and B modes of cosmic microwave background polarization. In this paper, we estimate this effect within the C_ℓOVER experiment observing bands (97, 150 and 220 GHz) for the selected observing site (Llano de Chajnantor, Atacama desert, Chile). The results show that the polarization signal from the clouds can be of the order of or even bigger than the cosmic microwave background expected polarization. Climatological data suggest that this signal is fairly constant over the whole year in Antarctica. On the other hand, the stronger seasonal variability in Atacama allows for a 50 per cent of clean observations during the dry season.  相似文献   

The age dependence of galaxy clustering     

Darren S. Reed  Fabio Governato  Thomas Quinn  Joachim Stadel  George Lake 《Monthly notices of the Royal Astronomical Society》2007,378(2):777-784

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Fossils explained 27: Theropod dinosaurs     

Darren Naish 《Geology Today》1999,15(6):234-239

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The Origin of Jets from Young Stars: Steady State Disk Wind Models Confronted to Observations     

Catherine Dougados  Sylvie Cabrit  Jonathan Ferreira  Nicholas Pesenti  Paulo Garcia  Darren O'brien 《Astrophysics and Space Science》2004,293(1-2):45-52

We discuss in this contribution constraints on the origin of mass-loss from young stars brought by recent observations at high angular resolution (0.1″ = 14 AU) of the inner regions of winds from T Tauri stars. Jet widths and collimation scales, the large extent of the velocity profile as well as the detection of rotation signatures agree with predictions from extended (R _e ≥ 1 AU) magneto-centrifugal disk wind ejection models. Detected poloidal and toroidal velocities imply large ejection efficiencies (ξ ? 0.05, λ ? 10), suggesting that thermal gradients (originating in an accretion heated disk corona for example) play an important role in accelerating the flow.  相似文献