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3,985 results on '"Murray, N."'

101. Eccentricity Evolution of Resonant Migrating Planets

Author

Murray, N., Paskowitz, M., and Holman, M.

Subjects
Astrophysics
Abstract

We examine the eccentricity evolution of a system of two planets locked in a mean motion resonance, in which the outer planet loses energy and angular momentum. The sink of energy and angular momentum could be either a gas or planetesimal disk. We show that the eccentricity of both planetary bodies can grow to large values, particularly if the inner body does not directly exchange energy or angular momentum with the disk. We analytically calculate the eccentricity damping rate in the case of a single planet migrating through a planetesimal disk. We present the results of numerical integrations of two resonant planets showing rapid growth of eccentricity. We also present integrations in which a Jupiter-mass planet is forced to migrate inward through a system of 5-10 roughly Earth mass planets. The migrating planet can eject or accrete the smaller bodies; roughly 5% of the mass (averaged over all the integrations) accretes onto the central star. The results are discussed in the context of the currently known extrasolar planetary systems., Comment: 35 pages, 7 figures

Published
2001
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102. A unified ML framework for solubility prediction across organic solvents

Author

Antony D. Vassileiou, Murray N. Robertson, Bruce G. Wareham, Mithushan Soundaranathan, Sara Ottoboni, Alastair J. Florence, Thoralf Hartwig, and Blair F. Johnston

Abstract

A generic framework for enhancing an initial solubility prediction with ML, even with simple methods and a modestly sized, sparse dataset. We dissect the setup to show the model “locking on” to the target system as more data are made available.

Published
2023

103. Anthropogenic modification of forests means only 40% of remaining forests have high ecosystem integrity

Author

Grantham, H. S., Duncan, A., Evans, T. D., Jones, K. R., Beyer, H. L., Schuster, R., Walston, J., Ray, J. C., Robinson, J. G., Callow, M., Clements, T., Costa, H. M., DeGemmis, A., Elsen, P. R., Ervin, J., Franco, P., Goldman, E., Goetz, S., Hansen, A., Hofsvang, E., Jantz, P., Jupiter, S., Kang, A., Langhammer, P., Laurance, W. F., Lieberman, S., Linkie, M., Malhi, Y., Maxwell, S., Mendez, M., Mittermeier, R., Murray, N. J., Possingham, H., Radachowsky, J., Saatchi, S., Samper, C., Silverman, J., Shapiro, A., Strassburg, B., Stevens, T., Stokes, E., Taylor, R., Tear, T., Tizard, R., Venter, O., Visconti, P., Wang, S., and Watson, J. E. M.

Published
2020
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104. Stellar Pollution in the Solar Neighborhood

Author

Murray, N., Chaboyer, B., Hansen, B., Arras, P., and Noyes, B.

Subjects
Astrophysics
Abstract

We study spectroscopically determined iron abundances of 642 solar-type stars to search for the signature of accreted iron-rich material. We find that the metallicity [Fe/H] of a subset of 466 main sequence stars, when plotted as a function of stellar mass, mimics the pattern seen in lithium abundances in open clusters. Using Monte Carlo models we find that, on average, these stars have accreted about 0.4 Earth masses of iron while on the main sequence. A much smaller sample of 19 stars in the Hertzsprung gap, which are slightly evolved and whose convection zones are significantly more massive, have lower average [Fe/H], and their metallicity shows no clear variation with stellar mass. These findings suggest that terrestrial-type material is common around solar type stars., Comment: 33 pages, 11 figures. Submitted to ApJ

Published
2000
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105. Simultaneous EUVE/ASCA/RXTE Observations of NGC 5548

Author

Chiang, J., Reynolds, C. S., Blaes, O. M., Nowak, M. A., Murray, N., Madejski, G., Marshall, H. L., and Magdziarz, P.

Subjects
Astrophysics
Abstract

We present simultaneous observations by EUVE, ASCA, and RXTE of the type~1 Seyfert galaxy NGC 5548. These data indicate that variations in the EUV emission (at $\sim 0.2 $keV) appear to lead similar modulations in higher energy ($\ga 1 $keV) X-rays by $\sim$10--30 ks. This is contrary to popular models which attribute the correlated variability of the EUV, UV and optical emission in type~1 Seyferts to reprocessing of higher energy radiation. This behavior instead suggests that the variability of the optical through EUV emission is an important driver for the variability of the harder X-rays which are likely produced by thermal Comptonization. We also investigate the spectral characteristics of the fluorescent iron K$\alpha$ line and Compton reflection emission. In contrast to prior measurements of these spectral features, we find that the iron K$\alpha$ line has a relatively small equivalent width ($W_{K\alpha} \sim 100 $eV) and that the reflection component is consistent with a covering factor which is significantly less than unity ($\Omega/2\pi \sim 0.4$--0.5). Notably, although the 2--10 keV X-ray flux varies by $\sim \pm 25$% and the derived reflection fraction appears to be constant throughout our observations, the flux in the Fe~K$\alpha$ line is also constant. This behavior is difficult to reconcile in the context of standard Compton reflection models., Comment: 13 pages, 6 figures, LaTeX, uses emulateapj.sty and apjfonts.sty, submitted to ApJ

Published
1999
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106. The Origin of Chaos in the Outer Solar System

Author

Murray, N. and Holman, M.

Subjects
Astrophysics
Abstract

Classical analytic theories of the solar system indicate that it is stable, but numerical integrations suggest that it is chaotic. This disagreement is resolved by a new analytic theory. The theory shows that the chaos among the Jovian planets results from the overlap of the components of a mean motion resonance among Jupiter, Saturn, and Uranus, and provides rough estimates of the Lyapunov time (10 million years) and the dynamical lifetime of Uranus (10^{18} years). The Jovian planets must have entered the resonance after all the gas and most of the planetesimals in the protoplanetary disk were removed., Comment: 19 pages, 3 figures, to appear in Science

Published
1999
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111. Patient Pathway Comparison for Total Hip Replacement in the United States and Germany — Why the Payment Model Matters

Author

Simon, Benedikt, primary, Navarro, Ronald, additional, Reddy, Nithin C., additional, Convissar, Jeff L., additional, Rabrenovich, Violeta, additional, Paxton, Elizabeth, additional, Fasig, Brian H., additional, Harris, Jessica, additional, Prentice, Heather, additional, Bottomley, Eric M., additional, Ross, Murray N., additional, Walker, Marco, additional, Grimberg, Alexander, additional, Spoden, Melissa, additional, and Malzahn, Juergen, additional

Published
2023
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118. Reverberation Mapping and the Disk Wind Model of the Broad Line Region

Author

Chiang, J. and Murray, N.

Subjects
Astrophysics
Abstract

Using the disk wind model of Murray et al. (1995), we calculate line profiles and frequency-resolved response functions for broad line emission from the surface of an accretion disk in an AGN in the presence of a radiatively driven wind. We find that the combined effects of the shears in the wind and in the disk itself produce anisotropic line emission which solves several well-known problems connected with disk models of the broad line region. In particular, the broadening of resonance lines such as \Civ, \Lya, and \Nv\/ can be attributed to orbital motion of the disk gas at radii as close as $\sim 10^{16}$~cm in Seyferts without requiring unrealistically large emission regions in order to produce single-peaked profiles. Furthermore, the anisotropy of the line emission results in frequency-dependent response functions which are no longer red-blue symmetric so that the time delays inferred for the various red and blue components of the line agree qualitatively with recent reverberation mapping observations of NGC~5548., Comment: 17 pages text, 8 postscript figures

Published
1995
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121. Migrating Planets

Author

Murray, N., Hansen, B., Holman, M., and Tremaine, S.

Published
1998

123. StrucNet: a global network for automated vegetation structure monitoring

Author

Sankey, T, Murray, N, Calders, K, Brede, B, Newnham, G, Culvenor, D, Armston, J, Bartholomeus, H, Griebel, A, Hayward, J, Junttila, S, Lau, A, Levick, S, Morrone, R, Origo, N, Pfeifer, M, Verbesselt, J, Herold, M, Sankey, T, Murray, N, Calders, K, Brede, B, Newnham, G, Culvenor, D, Armston, J, Bartholomeus, H, Griebel, A, Hayward, J, Junttila, S, Lau, A, Levick, S, Morrone, R, Origo, N, Pfeifer, M, Verbesselt, J, and Herold, M

Abstract

Climate change and increasing human activities are impacting ecosystems and their biodiversity. Quantitative measurements of essential biodiversity variables (EBV) and essential climate variables are used to monitor biodiversity and carbon dynamics and evaluate policy and management interventions. Ecosystem structure is at the core of EBVs and carbon stock estimation and can help to inform assessments of species and species diversity. Ecosystem structure is also used as an indirect indicator of habitat quality and expected species richness or species community composition. Spaceborne measurements can provide large-scale insight into monitoring the structural dynamics of ecosystems, but they generally lack consistent, robust, timely and detailed information regarding their full three-dimensional vegetation structure at local scales. Here we demonstrate the potential of high-frequency ground-based laser scanning to systematically monitor structural changes in vegetation. We present a proof-of-concept high-temporal ecosystem structure time series of 5 years in a temperate forest using terrestrial laser scanning (TLS). We also present data from automated high-temporal laser scanning that can allow upscaling of vegetation structure scanning, overcoming the limitations of a typically opportunistic TLS measurement approach. Automated monitoring will be a critical component to build a network of field monitoring sites that can provide the required calibration data for satellite missions to effectively monitor the structural dynamics of vegetation over large areas. Within this perspective, we reflect on how this network could be designed and discuss implementation pathways.

Published
2023

124. Impact of thoracic radiotherapy timing in limited-stage small-cell lung cancer: usefulness of the individual patient data meta-analysis

Author

De Ruysscher, D., Le Pechoux, C., Lueza, B., Paris, E., Pignon, J.P., Pijls-Johannesma, M., Veillard, A.S., Arriagada, Rodrigo, Baas, Paul, Blackstock, William, Chevret, Sylvie, Choy, Hak, Crawford, Jeffrey, Dafni, Urania, Dahlberg, Suzanne, De Ruysscher, Dirk, Hackshaw, Allan, Hasan, Baktiar, Johnson, David H., Le Pechoux, Cécile, Lebeau, Bernard, Lovato, James, Lueza, Béranger, Murray, Nevin, O’Brien, Mary, Paris, Emmanuelle, Pignon, Jean-Pierre, Pijls-Johannesma, Madelon, Price, Allan, Spiro, Stephen, Seymour, Lesley, Shibata, Taro, Skarlos, Dimosthenis, Takada, Minoru, Veillard, Anne-Sophie, Wang, Xiaofei, Le Péchoux, C., Johnson, D.H., O'Brien, M., Murray, N., Spiro, S., Wang, X., Takada, M., Lebeau, B., Blackstock, W., Skarlos, D., Baas, P., Choy, H., Price, A., Seymour, L., Arriagada, R., and Pignon, J.-P.

Published
2016
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131. Machine Learning Solutions to Regional Surface Ocean δ18O‐Salinity Relationships for Paleoclimatic Reconstruction.

Author

Murray, N. K., Muñoz, A. R., and Conroy, J. L.

Subjects
MACHINE learning, SEAWATER salinity, OCEAN, OCEAN temperature, OXYGEN isotopes, SEAWATER composition
Abstract

Stable isotope‐based reconstructions of past ocean salinity and hydroclimate depend on accurate, regionally constrained relationships between the stable oxygen isotopic composition of seawater (δ18Osw) and salinity in the surface ocean. An increasing number of δ18Osw observations suggest greater spatial variability in this relationship than previously considered, highlighting the need to reassess these relationships on a global scale. Here, we use available, paired δ18Osw and salinity data (N = 11,119) to create global interpolations of each variable. We then use a self‐organizing map, a specialized form of machine learning, to define 19 regions with unique δ18Osw‐salinity relationships in the surface (<50 m) ocean. Inclusion of atmospheric moisture‐related variables and oceanic tracer data in additional self‐organizing map experiments indicates global surface δ18Osw‐salinity spatial patterns are strongly forced by the atmosphere, as the SOM spatial output is highly similar despite no overlapping input data. Our approach is a useful update to the previously delimited regions, and highlights the utility of neural network pattern extraction in spatiotemporally sparse data sets. Plain Language Summary: Our understanding of past changes in the ocean and atmosphere often comes from information stored in biological marine carbonate archives. Stable oxygen isotope measurements from such archives record past ocean temperature as well as the stable oxygen isotopic composition of seawater. In the surface ocean, stable oxygen isotope values have a strong, linear, relationship with salinity, thought to be the result of evaporation and precipitation affecting stable isotope ratios and salinity in a similar manner. This permits reconstruction of past ocean salinity from marine carbonates, which may be used to infer large‐scale hydroclimate variability, in some cases. However, this manner of reconstruction relies on the linear isotope‐salinity relationship, which remains poorly constrained and is influenced by a combination of oceanic and atmospheric processes. In this work, we define regional isotope‐salinity relationships and broadly assess whether ocean or atmospheric processes play a larger role in the spatial distribution of these regions. We identify new regions compared to previous work, and find that over most of the ocean, precipitation, precipitation isotope values, and evaporation are important in setting seawater isotope‐salinity patterns. Key Points: Mixed‐layer regions with distinct salinity‐seawater δ18O paired values are identified by self‐organizing mapInclusion of atmospheric or oceanic tracers in the self‐organizing map shifts the spatial distribution of salinity‐seawater δ18O patternsRegion identification is still dependent on available observational data, but the throughput offered here enables updating as data increase [ABSTRACT FROM AUTHOR]

Published
2023
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135. Open Source Drug Discovery: Highly Potent Antimalarial Compounds Derived from the Tres Cantos Arylpyrroles

Author

Alice E. Williamson, Paul M. Ylioja, Murray N. Robertson, Yevgeniya Antonova-Koch, Vicky Avery, Jonathan B. Baell, Harikrishna Batchu, Sanjay Batra, Jeremy N. Burrows, Soumya Bhattacharyya, Felix Calderon, Susan A. Charman, Julie Clark, Benigno Crespo, Matin Dean, Stefan L. Debbert, Michael Delves, Adelaide S. M. Dennis, Frederik Deroose, Sandra Duffy, Sabine Fletcher, Guri Giaever, Irene Hallyburton, Francisco-Javier Gamo, Marinella Gebbia, R. Kiplin Guy, Zoe Hungerford, Kiaran Kirk, Maria J. Lafuente-Monasterio, Anna Lee, Stephan Meister, Corey Nislow, John P. Overington, George Papadatos, Luc Patiny, James Pham, Stuart A. Ralph, Andrea Ruecker, Eileen Ryan, Christopher Southan, Kumkum Srivastava, Chris Swain, Matthew J. Tarnowski, Patrick Thomson, Peter Turner, Iain M. Wallace, Timothy N. C. Wells, Karen White, Laura White, Paul Willis, Elizabeth A. Winzeler, Sergio Wittlin, and Matthew H. Todd

Subjects
Chemistry, QD1-999
Published
2016
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136. Volume-wise destruction of the antiferromagnetic Mott insulating state through quantum tuning

Author

Benjamin A. Frandsen, Lian Liu, Sky C. Cheung, Zurab Guguchia, Rustem Khasanov, Elvezio Morenzoni, Timothy J. S. Munsie, Alannah M. Hallas, Murray N. Wilson, Yipeng Cai, Graeme M. Luke, Bijuan Chen, Wenmin Li, Changqing Jin, Cui Ding, Shengli Guo, Fanlong Ning, Takashi U. Ito, Wataru Higemoto, Simon J. L. Billinge, Shoya Sakamoto, Atsushi Fujimori, Taito Murakami, Hiroshi Kageyama, Jose Antonio Alonso, Gabriel Kotliar, Masatoshi Imada, and Yasutomo J. Uemura

Subjects
Science
Abstract

Knowing whether a quantum phase transition is first- or second-order is crucial for understanding any associated exotic phenomena, but direct experimental evidence has been scarce. Here, Frandsen et al. report first-order magnetic quantum phase transitions in archetypal Mott systems, providing insight into the underlying quantum fluctuations.

Published
2016
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139. Incidence, Risk Factors, and Outcomes of Rhegmatogenous Retinal Detachment after Intravitreal Injections of Anti-VEGF for Retinal Diseases

Author

Gabrielle, Pierre-Henry, primary, Nguyen, Vuong, additional, Arnould, Louis, additional, Viola, Francesco, additional, Zarranz-Ventura, Javier, additional, Barthelmes, Daniel, additional, Creuzot-Garcher, Catherine, additional, Gillies, Mark, additional, Squirrell, D., additional, Gilhotra, J., additional, Brooijmans, C., additional, Tigchelaar-Besling, O., additional, Cohn, A., additional, Chen, F., additional, McGeorge, A., additional, Welch, S., additional, Jaross, N., additional, Peters, P., additional, Barry, R., additional, McLean, I., additional, Guillaumie, T., additional, Miri, A., additional, Korobelnik, J., additional, Gabrielle, P., additional, Weber, M., additional, Walid, B., additional, Tick, S., additional, Valen, S., additional, Field, A., additional, Wickremasinghe, S., additional, Dayajeewa, C., additional, Wells, J., additional, Essex, R., additional, Dunlop, A., additional, Michalova, K., additional, Ng, C., additional, Young, S., additional, MIMOUN, G., additional, Generic, C., additional, Guymer, R., additional, Carnota, P., additional, Torres Borrego, C., additional, Dolz Marco, R., additional, Gallego-Pinazo, R., additional, Pareja Esteban, J., additional, García Layana, A., additional, Saenz-de-Viteri, M., additional, Uzzan, J., additional, Ferrier, R., additional, Ah-Chan, J., additional, Chow, L., additional, Steiner, H., additional, Amini, A., additional, Clark, G., additional, Wittles, N., additional, Windle, P., additional, Vingerling, J., additional, Clement, C., additional, Gillies, M., additional, Hunt, A., additional, Beaumont, P., additional, Cottee, L., additional, Lee, K., additional, Mack, H., additional, Louw, Z., additional, Lusthaus, J., additional, Chen, J., additional, Landers, J., additional, Billing, K., additional, Saha, N., additional, Lake, S., additional, Qatarneh, D., additional, Phillips, R., additional, Perks, M., additional, Banon, K., additional, Guarro, M., additional, Londoño, G., additional, Rethati, C., additional, Sararols, L., additional, Suarez, J., additional, Viola, F., additional, Lan Oei, S., additional, Fraser-Bell, S., additional, Montejano Milner, R., additional, Arruabarrena, C., additional, Chong, E., additional, Lal, S., additional, Higueras, A., additional, Ascaso, F., additional, Boned Murillo, A., additional, Díaz, M., additional, Perez Rivases, G., additional, Alforja Castiella, S., additional, Bernal-Morales, C., additional, Casaroli-Marano, R., additional, Figueras-Roca, M., additional, Izquierdo-Serra, J., additional, Moll Udina, A., additional, Parrado-Carrillo, A., additional, Zarranz-Ventura, J., additional, escobar, j., additional, Lavid, F., additional, Alvarez Gil, M., additional, Catalán Muñoz, P., additional, Tena Sempere, M., additional, Cerri, L., additional, RICCI, F., additional, Broc Iturralde, L., additional, Campos Figueroa, P., additional, Gómez Sánchez, S., additional, Valldeperas, X., additional, Vilaplana, F., additional, Carreño, E., additional, Munoz Sanz, N., additional, Ventura Abreu, N., additional, Asencio Duran, M., additional, Calvo, P., additional, Sanchez, J., additional, Almazan Alonso, E., additional, Flores-Moreno, I., additional, Garcia Zamora, M., additional, Ciancas, E., additional, Gonzalez-Lopez, J., additional, de la Fuente, M., additional, Rodriguez Maqueda, M., additional, Cobos, E., additional, Lorenzo, D., additional, Cordoves, L., additional, Acebes, m., additional, Aparicio-Sanchis, S., additional, Fernández Hortelano, A., additional, Zarallo-Gallardo, J., additional, Azrak, C., additional, Piñero Sánchez, A., additional, Almuina-Varela, P., additional, García García, L., additional, Salinas Martínez, E., additional, Castilla Marti, M., additional, Campo Gesto, A., additional, Rodriguez Núñez, M., additional, Furness, G., additional, Ponsioen, T., additional, Wilson, G., additional, Manning, L., additional, McAllister, I., additional, Isaacs, Tim, additional, Invernizzi, A., additional, Castelnovo, L., additional, Michel, G., additional, Wolff, B., additional, Arnold, J., additional, Cass, H., additional, Chan, D., additional, Tan, T., additional, OToole, L., additional, Tang, K., additional, Chung, C., additional, Beylerian, H., additional, DAIEN, V., additional, Banerjee, G., additional, Morgan, M., additional, Reddie, I., additional, Ongkosuwito, J., additional, Verbraak, F., additional, Schlingemann, R., additional, piermarocchi, s., additional, Thompson, A., additional, Game, J., additional, Thompson, C., additional, Chalasani, R., additional, Chilov, M., additional, Fung, A., additional, Nothling, S., additional, Chong, R., additional, Hunyor, A., additional, Younan, C., additional, Barnes, R., additional, Sharp, D., additional, Vincent, A., additional, Murray, N., additional, Ah-Moye, S., additional, Hennings, C., additional, Mehta, H., additional, Monaco, P., additional, Cheung, G., additional, Karia, N., additional, Louis, D., additional, Every, S., additional, Lockie, P., additional, van Hecke, M., additional, van Lith-Verhoeven, J., additional, Wong, J., additional, Grigg, J., additional, Hinchcliffe, P., additional, Barthelmes, D., additional, Diaz De Durana Santa Coloma, E., additional, Garay-Aramburu, G., additional, Vujosevic, S., additional, Brosa Morros, H., additional, Daniell, M., additional, Harper, A., additional, Lim, L., additional, ODay, J., additional, Velazquez Villoria, D., additional, Hooper, C., additional, Klaassen-Broekema, N., additional, and Smit, R., additional

Published
2022
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144. LA REVOLUCIÓN LIBERAL EN ITALIA

Author

Murray N. Rothbard

Subjects
Geriatrics and Gerontology
Abstract

Hay esperanza para Estados Unidos. A pesar de nuestra política cada vez más socialista, y de nuestra cultura rápidamentedegenerada y enloquecida, hay esperanza. La primera señal maravillosa de esperanza fue, por supuesto, el colapso total del comunismo en la Unión Soviética y Europa del Este. Obviamente, no todos los problemas se resolvieron con este colapso, pero aún así, ¿quién podría haber creído que el comunismo totalitario, aparentemente todopoderoso, dirigido por un régimen unipartidista y respaldado por una enorme y despiadada policía secreta, no necesitaría ni una revolución sangrienta ni una larga y agotadora marcha por las instituciones para derribarlo?

Published
2022

148. 271 Impact of habitual levels of moderate to vigorous physical activity on forced expiratory volume in 1 second in children and young people with cystic fibrosis: Results from Project Fizzyo

Author

Main, E., primary, Filipow, N., additional, Raywood, E., additional, Tanriver, G., additional, Douglas, H., additional, Davies, G., additional, Murray, N., additional, O'Connor, R., additional, Stott, L., additional, Saul, G., additional, Kuzhagaliyev, T., additional, Liakhovich, O., additional, Furtuna, B., additional, van Schaik, T., additional, Booth, J., additional, Dawson, C., additional, Hill, L., additional, Kapoor, K., additional, and Stanojevic, S., additional

Published
2022
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149. 276 Effects of quantity and quality of daily airway clearance treatments on lung function in children and young people with cystic fibrosis: Results from Project Fizzyo

Author

Raywood, E., primary, Filipow, N., additional, Stanojevic, S., additional, Shannon, H., additional, Douglas, H., additional, Tanriver, G., additional, Murray, N., additional, O'Connor, R., additional, Hill, L., additional, Dawson, C., additional, Davies, G., additional, Stott, L., additional, Saul, G., additional, Kuzhagaliyev, T., additional, van Schaik, T., additional, Furtuna, B., additional, Liakhovich, O., additional, Booth, J., additional, Kapoor, K., additional, and Main, E., additional

Published
2022
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