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San Jose State University

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2015

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Articles 1 - 30 of 39

Full-Text Articles in Physical Sciences and Mathematics

Logistic Regression Models To Predict Solvent Accessible Residues Using Sequence- And Homology-Based Qualitative And Quantitative Descriptors Applied To A Domain-Complete X-Ray Structure Learning Set, Reecha Nepal, Joanna Spencer, Guneet Bhogal, Amulya Nedunuri, Thomas Poelman, Thejas Kamath, Edwin Chung, Katherine Kantardjieff, Andrea Gottlieb, Brooke Lustig Dec 2015

Logistic Regression Models To Predict Solvent Accessible Residues Using Sequence- And Homology-Based Qualitative And Quantitative Descriptors Applied To A Domain-Complete X-Ray Structure Learning Set, Reecha Nepal, Joanna Spencer, Guneet Bhogal, Amulya Nedunuri, Thomas Poelman, Thejas Kamath, Edwin Chung, Katherine Kantardjieff, Andrea Gottlieb, Brooke Lustig

Faculty Publications, Chemistry

A working example of relative solvent accessibility (RSA) prediction for proteins is presented. Novel logistic regression models with various qualitative descriptors that include amino acid type and quantitative descriptors that include 20- and six-term sequence entropy have been built and validated. A domain-complete learning set of over 1300 proteins is used to fit initial models with various sequence homology descriptors as well as query residue qualitative descriptors. Homology descriptors are derived from BLASTp sequence alignments, whereas the RSA values are determined directly from the crystal structure. The logistic regression models are fitted using dichotomous responses indicating buried or accessible solvent, …

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Cooling Atomic Gases With Disorder, Ehsan Khatami, Thereza Paiva, Shuxiang Yang, Valéry Rousseau, Mark Jarrell, Juana Moreno, Randall Hulet, Richard Scalettar Dec 2015

Cooling Atomic Gases With Disorder, Ehsan Khatami, Thereza Paiva, Shuxiang Yang, Valéry Rousseau, Mark Jarrell, Juana Moreno, Randall Hulet, Richard Scalettar

Faculty Publications

Cold atomic gases have proven capable of emulating a number of fundamental condensed matter phenomena including Bose-Einstein condensation, the Mott transition, Fulde-Ferrell-Larkin-Ovchinnikov pairing, and the quantum Hall effect. Cooling to a low enough temperature to explore magnetism and exotic superconductivity in lattices of fermionic atoms remains a challenge. We propose a method to produce a low temperature gas by preparing it in a disordered potential and following a constant entropy trajectory to deliver the gas into a nondisordered state which exhibits these incompletely understood phases. We show, using quantum Monte Carlo simulations, that we can approach the Néel temperature of …

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Topography And Tropical Cyclone Structure Influence On Eyewall Evolution In Typhoon Sinlaku (2008), Cheng-Hsiang Chih, Kun-Hsuan Chou, Sen Chiao Oct 2015

Topography And Tropical Cyclone Structure Influence On Eyewall Evolution In Typhoon Sinlaku (2008), Cheng-Hsiang Chih, Kun-Hsuan Chou, Sen Chiao

Faculty Publications, Meteorology and Climate Science

Typhoon Sinlaku (2008) was a tropical system that affected many countries in East Asia. Besides the loss of life and economic damage, many scientific questions are associated with this system that need to be addressed. A series of numerical simulations were conducted in this study using V3.2 of the advanced research version of the Weather Research and Forecasting (WRF-ARW) model to examine the impacts of different terrain conditions and vortex structures on the eyewall evolution when Sinlaku was crossing Taiwan. The sensitivity experiments using different vortex structures show that a storm of the same intensity with a larger eyewall radius …

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The Sluggs Survey: Globular Cluster Kinematics In A ‘Double Sigma’ Galaxy – Ngc 4473, Adebusola Alabi, Caroline Foster, Duncan Forbes, Aaron Romanowsky, Nicola Pastorello, Jean Brodie, Lee Spitler, Jay Strader, Christopher Usher Sep 2015

The Sluggs Survey: Globular Cluster Kinematics In A ‘Double Sigma’ Galaxy – Ngc 4473, Adebusola Alabi, Caroline Foster, Duncan Forbes, Aaron Romanowsky, Nicola Pastorello, Jean Brodie, Lee Spitler, Jay Strader, Christopher Usher

Faculty Publications

NGC 4473 is a so-called double sigma (2σ) galaxy, i.e. a galaxy with rare, double peaks in its 2D stellar velocity dispersion. Here, we present the globular cluster (GC) kinematics in NGC 4473 out to ∼10Re (effective radii) using data from combined Hubble Space Telescope/Advanced Camera for Surveys and Subaru/Suprime-Cam imaging and Keck/Deep Imaging Multi-Object Spectrograph. We find that the 2σ nature of NGC 4473 persists up to 3Re, though it becomes misaligned to the photometric major axis. We also observe a significant offset between the stellar and GC rotation amplitudes. This offset can be understood as a co-addition of …

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The Sluggs Survey: Inferring The Formation Epochs Of Metal-Poor And Metal-Rich Globular Clusters, Duncan Forbes, Nicola Pastorello, Aaron Romanowsky, Christopher Usher, Jean Brodie, Jay Strader Sep 2015

The Sluggs Survey: Inferring The Formation Epochs Of Metal-Poor And Metal-Rich Globular Clusters, Duncan Forbes, Nicola Pastorello, Aaron Romanowsky, Christopher Usher, Jean Brodie, Jay Strader

Faculty Publications

We present a novel, observationally-based framework for the formation epochs and sites of globular clusters (GCs) in a cosmological context. Measuring directly the mean ages of the metal-poor and metal-rich GC subpopulations in our own Galaxy, and in other galaxies, is observationally challenging. Here we apply an alternative approach utilizing the property that the galaxy mass–metallicity relation is a strong function of redshift (or look-back age) but is relatively insensitive to galaxy mass for massive galaxies. Assuming that GCs follow galaxy mass–metallicity relations that evolve with redshift, one can estimate the mean formation epochs of the two GC subpopulations by …

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Vegas: A Vst Early-Type Galaxy Survey: I. Presentation, Wide-Field Surface Photometry, And Substructures In Ngc 4472, Massimo Capaccioli, Marilena Spavone, Aniello Grado, Enrichetta Iodice, Luca Limatola, Nicola Napolitano, Michele Cantiello, Maurizio Paolillo, Aaron Romanowsky, Duncan Forbes, Thomas Puzia, Gabriella Raimondo, Pietro Schipani Sep 2015

Vegas: A Vst Early-Type Galaxy Survey: I. Presentation, Wide-Field Surface Photometry, And Substructures In Ngc 4472, Massimo Capaccioli, Marilena Spavone, Aniello Grado, Enrichetta Iodice, Luca Limatola, Nicola Napolitano, Michele Cantiello, Maurizio Paolillo, Aaron Romanowsky, Duncan Forbes, Thomas Puzia, Gabriella Raimondo, Pietro Schipani

Faculty Publications

Context. We present the VST Early-type GAlaxy Survey (VEGAS), which is designed to obtain deep multiband photometry in g,r,i, of about one hundred nearby galaxies down to 27.3, 26.8, and 26 mag/arcsec2 respectively, using the ESO facility VST/OmegaCAM.Aims. The goals of the survey are 1) to map the light distribution up to ten effective radii, re; 2) to trace color gradients and surface brightness fluctuation gradients out to a few re for stellar population characterization; and 3) to obtain a full census of the satellite systems (globular clusters and dwarf galaxies) out to 20% of the galaxy virial radius. The …

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Vimos Mosaic Integral-Field Spectroscopy Of The Bulge And Disc Of The Early-Type Galaxy Ngc 4697, C. Spiniello, N. Napolitano, L. Coccato, V. Pota, Aaron Romanowsky, C. Tortora, G. Covone, M. Capaccioli Sep 2015

Vimos Mosaic Integral-Field Spectroscopy Of The Bulge And Disc Of The Early-Type Galaxy Ngc 4697, C. Spiniello, N. Napolitano, L. Coccato, V. Pota, Aaron Romanowsky, C. Tortora, G. Covone, M. Capaccioli

Faculty Publications

No abstract provided.

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The Sluggs Survey: Combining Stellar And Globular Cluster Metallicities In The Outer Regions Of Early-Type Galaxies, Nicola Pastorello, Duncan Forbes, Christopher Usher, Jean Brodie, Aaron Romanowsky, Jay Strader, Lee Spitler, Adebusola Alabi, Caroline Foster, Zachary Jennings, Sreeja Kartha, Vincenzo Pota Aug 2015

The Sluggs Survey: Combining Stellar And Globular Cluster Metallicities In The Outer Regions Of Early-Type Galaxies, Nicola Pastorello, Duncan Forbes, Christopher Usher, Jean Brodie, Aaron Romanowsky, Jay Strader, Lee Spitler, Adebusola Alabi, Caroline Foster, Zachary Jennings, Sreeja Kartha, Vincenzo Pota

Faculty Publications

The outer halo regions of early-type galaxies carry key information about their past accretion history. However, spectroscopically probing the stellar component at such galactocentric radii is still challenging. Using the DEep Imaging Multi-Object Spectrograph on the Keck, we have been able to measure the metallicities of the stellar and globular cluster components in 12 early-type galaxies out to more than 10Re. We find similar metallicity gradients for the metal-poor and metal-rich globular cluster subpopulations, suggesting a common formation process for the two subpopulations. This is in conflict with most current theoretical predictions, where the metal-poor globular clusters are thought to …

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Comparisons Of Cirrus Cloud Properties Between Polluted And Pristine Air Based On In-Situ Observations From The Nasa Attrex, Nsf Hippo And Eu Inca Campaigns, Minghui Diao, Jorgen Jensen Jul 2015

Comparisons Of Cirrus Cloud Properties Between Polluted And Pristine Air Based On In-Situ Observations From The Nasa Attrex, Nsf Hippo And Eu Inca Campaigns, Minghui Diao, Jorgen Jensen

Faculty Publications, Meteorology and Climate Science

Cirrus clouds, covering about 30% of the Earth’s surface area, play an important role in the climate and weather systems. Cirrus cloud radiative forcing (cooling or warming) is influenced by their microphysical (e.g., ice crystal number concentration and size distribution) and macroscopic (e.g., spatial extent) properties. Currently it is still unclear how the formation of cirrus clouds and their microphysical properties are influenced by anthropogenic emissions. In this work, we use in-situ observations from three flight campaigns to compare the cirrus cloud properties between polluted and pristine regions. Our dataset includes: (1) the NASA Airborne Tropical Tropopause Experiment (ATTREX) campaign …

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The Sluggs Survey: Multipopulation Dynamical Modelling Of The Elliptical Galaxy Ngc 1407 From Stars And Globular Clusters, Vincenzo Pota, Aaron Romanowsky, Jean Brodie, Jorge Peñarrubia, Duncan Forbes, Nicola Napolitano, Caroline Foster, Matthew Walker, Jay Strader, Joel Roediger Jul 2015

The Sluggs Survey: Multipopulation Dynamical Modelling Of The Elliptical Galaxy Ngc 1407 From Stars And Globular Clusters, Vincenzo Pota, Aaron Romanowsky, Jean Brodie, Jorge Peñarrubia, Duncan Forbes, Nicola Napolitano, Caroline Foster, Matthew Walker, Jay Strader, Joel Roediger

Faculty Publications

No abstract provided.

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Frustrated Abc Triblock Terpolymers Morphologies, Madalyn Radlauer, Yusuke Asai, Christophe Sinturel, Marc Hillmyer Jun 2015

Frustrated Abc Triblock Terpolymers Morphologies, Madalyn Radlauer, Yusuke Asai, Christophe Sinturel, Marc Hillmyer

Faculty Publications, Chemistry

No abstract provided.

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Investigating The Paleoecological Consequences Of Supercontinent Breakup: Sponges Clean Up In The Early Jurassic, Frank Corsetti, Kathleen Ritterbush, David Bottjer, Sarah Greene, Yadira Ibarra, Joyce Yager, A. Joshua West, William Berelson, Silvia Rosas, Thorsten Becker, Naomi Levine, Sean Loyd, Rowan Martindale, Victoria Petryshyn, Nathan Carroll, Elizabeth Petsios, Olivia Piazza, Carlie Pietsch, Jessica Stellmann, Jeffrey Thompson, Kirstin Washington, Dylan Wilmeth Jun 2015

Investigating The Paleoecological Consequences Of Supercontinent Breakup: Sponges Clean Up In The Early Jurassic, Frank Corsetti, Kathleen Ritterbush, David Bottjer, Sarah Greene, Yadira Ibarra, Joyce Yager, A. Joshua West, William Berelson, Silvia Rosas, Thorsten Becker, Naomi Levine, Sean Loyd, Rowan Martindale, Victoria Petryshyn, Nathan Carroll, Elizabeth Petsios, Olivia Piazza, Carlie Pietsch, Jessica Stellmann, Jeffrey Thompson, Kirstin Washington, Dylan Wilmeth

Faculty Publications

The continued release of fossil fuel carbon into the atmosphere today means it is imperative to understand Earth system response to CO2 rise, and the geologic record offers unique opportunities to investigate such behavior. Stomatal and paleosol proxies demonstrate a large change in atmospheric pCO2 across the Triassic-Jurassic (T-J) transition, concomitant with the eruption and emplacement of the Central Atlantic Magmatic Province (CAMP) and the splitting of Pangea. As one of the “big 5” mass extinctions—when the so-called modern fauna was particularly hard hit—we know the biosphere was severely affected during this time, but the details are relatively poorly understood, …

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A Sluggs And Gemini/Gmos Combined Study Of The Elliptical Galaxy M60: Wide-Field Photometry And Kinematics Of The Globular Cluster System, Vincenzo Pota, Jean Brodie, Terry Bridges, Jay Strader, Aaron Romanowsky, Alexa Villaume, Zach Jennings, Favio Faifer, Nicola Pastorello, Duncan Forbes, Ainsley Campbell, Christopher Usher, Caroline Foster, Lee Spitler, Nelson Caldwell, Juan Forte, Mark Norris, Stephen Zepf, Michael Beasley, Karl Gebhardt, David Hanes, Ray Sharples, Jacob Arnold Jun 2015

A Sluggs And Gemini/Gmos Combined Study Of The Elliptical Galaxy M60: Wide-Field Photometry And Kinematics Of The Globular Cluster System, Vincenzo Pota, Jean Brodie, Terry Bridges, Jay Strader, Aaron Romanowsky, Alexa Villaume, Zach Jennings, Favio Faifer, Nicola Pastorello, Duncan Forbes, Ainsley Campbell, Christopher Usher, Caroline Foster, Lee Spitler, Nelson Caldwell, Juan Forte, Mark Norris, Stephen Zepf, Michael Beasley, Karl Gebhardt, David Hanes, Ray Sharples, Jacob Arnold

Faculty Publications

We present new wide-field photometry and spectroscopy of the globular clusters (GCs) around NGC 4649 (M60), the third brightest galaxy in the Virgo cluster. Imaging of NGC 4649 was assembled from a recently obtained Hubble Space Telescope/Advanced Camera for Surveys mosaic, and new Subaru/Suprime-Cam and archival Canada–France–Hawaii Telescope/MegaCam data. About 1200 sources were followed up spectroscopically using combined observations from three multi-object spectrographs: Keck/Deep Imaging Multi-Object Spectrograph, Gemini/Gemini Multi-Object Spectrograph and Multiple Mirror Telescope/Hectospec. We confirm 431 unique GCs belonging to NGC 4649, a factor of 3.5 larger than previous data sets and with a factor of 3 improvement in …

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Distributions Of Ice Supersaturation And Ice Crystals From Airborne Observations In Relation To Upper Tropospheric Dynamical Boundaries, Minghui Diao, Jorgen Jensen, Laura Pan, Cameron Homeyer, Shawn Honomichl, James Bresch, Aaron Bansemer May 2015

Distributions Of Ice Supersaturation And Ice Crystals From Airborne Observations In Relation To Upper Tropospheric Dynamical Boundaries, Minghui Diao, Jorgen Jensen, Laura Pan, Cameron Homeyer, Shawn Honomichl, James Bresch, Aaron Bansemer

Faculty Publications, Meteorology and Climate Science

Ice supersaturation (ISS) is the prerequisite condition for cirrus cloud formation. To examine multiscale dynamics' influences on ISS formation, we analyze in situ aircraft observations (~200 m scale) over North America in coordinates relative to dynamical boundaries in the upper troposphere and lower stratosphere. Two case studies demonstrate that ISS formation is likely influenced by mesoscale uplifting, small-scale waves, and turbulence. A collective analysis of 15 flights in April–June 2008 shows that the top layers of ISS and ice crystal distributions are strongly associated with thermal tropopause height. In addition, the average occurrence frequencies of ISS and ice crystals on …

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How Elevated Is The Dynamical-To-Stellar Mass Ratio Of The Ultracompact Dwarf S999?, Joachim Janz, Duncan Forbes, Mark Norris, Jay Strader, Samantha Penny, Martina Fagioli, Aaron Romanowsky May 2015

How Elevated Is The Dynamical-To-Stellar Mass Ratio Of The Ultracompact Dwarf S999?, Joachim Janz, Duncan Forbes, Mark Norris, Jay Strader, Samantha Penny, Martina Fagioli, Aaron Romanowsky

Faculty Publications

No abstract provided.

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Comparing The Model-Simulated Global Warming Signal To Observations Using Empirical Estimates Of Unforced Noise, Patrick T. Brown, Wenhong Li, Eugene C. Cordero, Steven A. Mauget Apr 2015

Comparing The Model-Simulated Global Warming Signal To Observations Using Empirical Estimates Of Unforced Noise, Patrick T. Brown, Wenhong Li, Eugene C. Cordero, Steven A. Mauget

Faculty Publications, Meteorology and Climate Science

The comparison of observed global mean surface air temperature (GMT) change to the mean change simulated by climate models has received much public and scientific attention. For a given global warming signal produced by a climate model ensemble, there exists an envelope of GMT values representing the range of possible unforced states of the climate system (the Envelope of Unforced Noise; EUN). Typically, the EUN is derived from climate models themselves, but climate models might not accurately simulate the correct characteristics of unforced GMT variability. Here, we simulate a new, empirical, EUN that is based on instrumental and reconstructed surface …

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Vegas-Sss. A Vst Early-Type Galaxy Survey: Analysis Of Small Stellar Systems: Testing The Methodology On The Globular Cluster System In Ngc 3115⋆, Michele Cantiello, Massimo Capaccioli, Nicola Napolitano, Aniello Grado, Luca Limatola, Maurizio Paolillo, Enrica Iodice, Aaron Romanowsky, Duncan Forbes, Gabriella Raimondo, Marilena Spavone, Francesco La Barbera, Thomas Puzia, Pietro Schipani Apr 2015

Vegas-Sss. A Vst Early-Type Galaxy Survey: Analysis Of Small Stellar Systems: Testing The Methodology On The Globular Cluster System In Ngc 3115⋆, Michele Cantiello, Massimo Capaccioli, Nicola Napolitano, Aniello Grado, Luca Limatola, Maurizio Paolillo, Enrica Iodice, Aaron Romanowsky, Duncan Forbes, Gabriella Raimondo, Marilena Spavone, Francesco La Barbera, Thomas Puzia, Pietro Schipani

Faculty Publications

We present a study of globular clusters (GCs) and other small stellar systems (SSSs) in the field of NGC 3115, observed as part of the ongoing wide-field imaging survey VEGAS, carried out with the 2.6 m VST telescope. We used deep g and i observations of NGC 3115, a well-studied lenticular galaxy that is covered excellently well in the scientific literature. This is fundamental to test the methodologies, verify the results, and probe the capabilities of the VEGAS-SSS. Leveraging the large field of view of the VST allowed us to accurately study the distribution and properties of SSSs as a …

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Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks Apr 2015

Glowing Seashells: Diversity Of Fossilized Coloration Patterns On Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells From The Neogene Of The Dominican Republic, Jonathan R. Hendricks

Faculty Publications

The biology of modern Conidae (cone snails)—which includes the hyperdiverse genus Conus—has been intensively studied, but the fossil record of the clade remains poorly understood, particularly within an evolutionary framework. Here, ultraviolet light is used to reveal and characterize the original shell coloration patterns of 28 species of cone snails from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic. These fossils come from the upper Miocene Cercado Fm. and lower Pliocene Gurabo Fm., and range in age from about 6.6-4.8 Ma. Comparison of the revealed coloration patterns with those of extant species allow the taxa to …

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Observation Of Antiferromagnetic Correlations In The Hubbard Model With Ultracold Atoms, Russell Hart, Pedro Duarte, Tsung-Lin Yang, Xinxing Liu, Thereza Paiva, Ehsan Khatami, Richard Scalettar, Nandini Trivedi, David Huse, Randall Hulet Mar 2015

Observation Of Antiferromagnetic Correlations In The Hubbard Model With Ultracold Atoms, Russell Hart, Pedro Duarte, Tsung-Lin Yang, Xinxing Liu, Thereza Paiva, Ehsan Khatami, Richard Scalettar, Nandini Trivedi, David Huse, Randall Hulet

Faculty Publications

Ultracold atoms in optical lattices have great potential to contribute to a better understanding of some of the most important issues in many-body physics, such as high-temperature superconductivity. The Hubbard model—a simplified representation of fermions moving on a periodic lattice—is thought to describe the essential details of copper oxide superconductivity. This model describes many of the features shared by the copper oxides, including an interaction-driven Mott insulating state and an antiferromagnetic (AFM) state. Optical lattices filled with a two-spin-component Fermi gas of ultracold atoms can faithfully realize the Hubbard model with readily tunable parameters, and thus provide a platform for …

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Dust Deposition In The Eastern Indian Ocean: The Ocean Perspective From Antarctica To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, Clifton Buck, William Landing Mar 2015

Dust Deposition In The Eastern Indian Ocean: The Ocean Perspective From Antarctica To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, Clifton Buck, William Landing

Faculty Publications

Atmospheric deposition is an important but still poorly constrained source of trace micronutrients to the open ocean because of the dearth of in situ measurements of total deposition (i.e., wet + dry deposition) in remote regions. In this work, we discuss the upper ocean distribution of dissolved Fe and Al in the eastern Indian Ocean along a 95°E meridional transect spanning the Antarctic margin to the Bay of Bengal. We use the mixed layer concentration of dissolved Al in conjunction with empirical data in a simple steady state model to produce 75 estimates of total dust deposition that we compare …

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Dissolved Fe And Al In The Upper 1000 M Of The Eastern Indian Ocean: A High‐Resolution Transect Along 95°E From The Antarctic Margin To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, William Landing, Peter Morton, Clifton Buck, Pamela Barrett, Joseph Resing Mar 2015

Dissolved Fe And Al In The Upper 1000 M Of The Eastern Indian Ocean: A High‐Resolution Transect Along 95°E From The Antarctic Margin To The Bay Of Bengal, Maxime Grand, Christopher Measures, Mariko Hatta, William Hiscock, William Landing, Peter Morton, Clifton Buck, Pamela Barrett, Joseph Resing

Faculty Publications

A high‐resolution section of dissolved iron (dFe) and aluminum (dAl) was obtained along ~95°E in the upper 1000 m of the eastern Indian Ocean from the Antarctic margin (66°S) to the Bay of Bengal (18°N) during the U.S. Climate Variability and Predictability (CLIVAR) CO2 Repeat Hydrography I08S and I09N sections (February–April 2007). In the Southern Ocean, low concentrations of dAl (<1 n M) reflect the negligible dust inputs impacting the water masses subducted in the circumpolar domain. The low dAl concentrations characterizing the Southern Ocean terminate near 45°S, probably because of the advection of subtropical water masses that received dust and sedimentary inputs in their formation region. Our subsurface dFe data near the southern Kerguelen Plateau were significantly higher than historical observations in other Indian sectors of the Southern Ocean. We surmise that the offshore advection of dFe‐rich waters along the western flank of the southern Kerguelen plateau and enhanced vertical mixing could contribute to this elevated subsurface dFe inventory. Elevated subsurface particulate and dFe levels downstream of the northern Kerguelen Plateau may reflect long‐range lateral transport from the plateau's sediments and/or remineralization inputs. At the northern edge of the south Indian subtropical gyre, the deposition of Australian dust, possibly combined with the advection of dAl‐enriched waters from the Indonesian Throughflow, creates a region of elevated dAl in the upper 400 m but without a corresponding enrichment in dFe. In the northern Indian Ocean, the South Equatorial Current constitutes a remarkable biogeochemical front separating the oxygen‐rich and dFe‐poor subtropical gyre waters from the dFe‐rich and oxygen‐depleted waters of the northern Indian Ocean. By tracing the accumulation of macronutrients and dFe along the advective pathway of Indian Central Water, we show that the central waters of the northern Indian Ocean receive excess dFe in addition to that produced by remineralization inputs. The resuspension of shelf sediments and release of pore waters probably contribute to the elevated dFe and dAl levels observed below the highly stratified upper layers of the Bay of Bengal.

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Charged Skyrmions On The Surface Of A Topological Insulator, Hilary M. Hurst, Dimitry K. Efimkin, Jiadong Zang, Victor Galitski Feb 2015

Charged Skyrmions On The Surface Of A Topological Insulator, Hilary M. Hurst, Dimitry K. Efimkin, Jiadong Zang, Victor Galitski

Faculty Research, Scholarly, and Creative Activity

We consider the interplay between magnetic skyrmions in an insulating thin film and the Dirac surface states of a 3D topological insulator (TI), coupled by proximity effect. The magnetic texture of skyrmions can lead to confinement of Dirac states at the skyrmion radius, where out of plane magnetization vanishes. This confinement can result in charging of the skyrmion texture. The presence of bound states is robust in an external magnetic field, which is needed to stabilize skyrmions. It is expected that for relevant experimental parameters skyrmions will have a few bound states that can be tuned using an external magnetic …

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Detection Of A Distinct Metal-Poor Stellar Halo In The Early-Type Galaxy Ngc 3115*, Mark Peacock, Jay Strader, Aaron Romanowsky, Jean Brodie Feb 2015

Detection Of A Distinct Metal-Poor Stellar Halo In The Early-Type Galaxy Ngc 3115*, Mark Peacock, Jay Strader, Aaron Romanowsky, Jean Brodie

Faculty Publications

We present the resolved stellar populations in the inner and outer halo of the nearby lenticular galaxy NGC 3115. Using deep Hubble Space Telescope observations, we analyze stars 2 mag fainter than the tip of the red giant branch (TRGB). We study three fields along the minor axis of this galaxy, 19, 37, and 54 kpc from its center—corresponding to 7, 14, and 21 effective radii (re ). Even at these large galactocentric distances, all of the fields are dominated by a relatively enriched population, with the main peak in the metallicity distribution decreasing with radius from [Z/H] ~ –0.5 …

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Compressibility Of A Fermionic Mott Insulator Of Ultracold Atoms, Pedro Duarte, Russell Hart, Tsung-Lin Yang, Xinxing Liu, Thereza Paiva, Ehsan Khatami, Richard Scalettar, Nandini Trivedi, Randall Hulet Feb 2015

Compressibility Of A Fermionic Mott Insulator Of Ultracold Atoms, Pedro Duarte, Russell Hart, Tsung-Lin Yang, Xinxing Liu, Thereza Paiva, Ehsan Khatami, Richard Scalettar, Nandini Trivedi, Randall Hulet

Faculty Publications

We characterize the Mott insulating regime of a repulsively interacting Fermi gas of ultracold atoms in a three-dimensional optical lattice. We use in situ imaging to extract the central density of the gas and to determine its local compressibility. For intermediate to strong interactions, we observe the emergence of a plateau in the density as a function of atom number, and a reduction of the compressibility at a density of one atom per site, indicating the formation of a Mott insulator. Comparisons to state-of-the-art numerical simulations of the Hubbard model over a wide range of interactions reveal that the temperature …

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Cold Smoke: Smoke-Induced Density Currents Cause Unexpected Smoke Transport Near Large Wildfires, Neil Lareau, Craig Clements Jan 2015

Cold Smoke: Smoke-Induced Density Currents Cause Unexpected Smoke Transport Near Large Wildfires, Neil Lareau, Craig Clements

Faculty Publications, Meteorology and Climate Science

The first observations of smoke-induced density currents originating from large wildfires are presented. Using a novel mobile Doppler lidar and additional in situ measurements, we document a deep (~ 2 km) smoke-filled density current that propagates more than 25 km at speeds up to 4.5 m s−1 near a large forest fire in northern California. Based on these observations we show that the dynamics governing the spread of the smoke layer result from differential solar heating between the smoke-filled and smoke-free portions of the atmospheric boundary layer. A calculation of the theoretical density current speed agrees well with the observed …

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Potential Switchable Circularly Polarized Luminescence From Chiral Cyclometalated Platinum(Ii) Complexes, Xiao-Peng Zhang Zhang, Victoria Chang, Jian Liu, Xiao-Liang Yang, Wei Huan, Yizhi Li, Cheng-Hui Li, Gilles Muller, Xiao-Zeng You Jan 2015

Potential Switchable Circularly Polarized Luminescence From Chiral Cyclometalated Platinum(Ii) Complexes, Xiao-Peng Zhang Zhang, Victoria Chang, Jian Liu, Xiao-Liang Yang, Wei Huan, Yizhi Li, Cheng-Hui Li, Gilles Muller, Xiao-Zeng You

Faculty Publications, Chemistry

A series of chiral cyclometalated platinum(II) complexes, [Pt((−)-L1)(Dmpi)]Cl ((−)-1), [Pt((+)-L1)(Dmpi)]Cl ((+)-1), [Pt((−)-L2)(Dmpi)]Cl ((−)-2), [Pt((+)-L2)(Dmpi)]Cl ((+)-2), [Pt3((−)-L2)2(Dmpi)4](ClO4)4 ((−)-3), and [Pt3((+)-L2)2(Dmpi)4](ClO4)4 ((+)-3) [(−)-L1 = (−)-4,5-pinene-6′-phenyl-2,2′-bipyridine, (+)-L1 = (+)-4,5-pinene-6′-phenyl-2,2′-bipyridine), (−)-L2 = (−)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, (+)-L2 = (+)-1,3-bis(2-(4,5-pinene)pyridyl)benzene, Dmpi = 2,6-dimethylphenyl isocyanide], have been designed and synthesized. In aqueous solutions, (−)-1 and (+)-1 aggregate into one-dimensional helical chain structures through Pt···Pt, π–π, and hydrophobic–hydrophobic interactions. (−)-3 and (+)-3 represent a novel helical structure with Pt–Pt bonds. The formation of helical structures results in enhanced and distinct chiroptical properties as evidenced by circular dichroism spectra. Circularly polarized luminescence (CPL) was observed from the aggregates of (−)-1 and …

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Enantio-Enriched Cpl-Active Helicene–Bipyridine–Rhenium Complexes, Nidal Saleh, Monika Srebro, Thibault Reynaldo, Nicolas Vanthuyne, Loïc Toupet, Victoria Chang, Gilles Muller, J. Gareth-Williams, Christian Roussel, Jochen Autschbach, Jeanne Crassous Jan 2015

Enantio-Enriched Cpl-Active Helicene–Bipyridine–Rhenium Complexes, Nidal Saleh, Monika Srebro, Thibault Reynaldo, Nicolas Vanthuyne, Loïc Toupet, Victoria Chang, Gilles Muller, J. Gareth-Williams, Christian Roussel, Jochen Autschbach, Jeanne Crassous

Faculty Publications, Chemistry

The incorporation of a rhenium atom within an extended helical π-conjugated bi-pyridine system impacts the chiroptical and photophysical properties of the resulting neutral or cationic complexes, leading to the first examples of rhenium-based phosphors that exhibit circularly polarized luminescence.

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Extremal Theorems For Degree Sequence Packing And The Two-Color Discrete Tomography Problem, Jennifer Diemunsch, Michael Ferrara, Sogol Jahanbekam, James Shook Jan 2015

Extremal Theorems For Degree Sequence Packing And The Two-Color Discrete Tomography Problem, Jennifer Diemunsch, Michael Ferrara, Sogol Jahanbekam, James Shook

Faculty Publications

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Observations Of Fire-Induced Turbulence Regimes During Low-Intensity Wildland Fires In Forested Environments: Implications For Smoke Dispersion, Warren Heilman, Craig Clements, Daisuke Seto, Xindi Bian, Kenneth Clark, Nicholas Skowronski, John Hom Jan 2015

Observations Of Fire-Induced Turbulence Regimes During Low-Intensity Wildland Fires In Forested Environments: Implications For Smoke Dispersion, Warren Heilman, Craig Clements, Daisuke Seto, Xindi Bian, Kenneth Clark, Nicholas Skowronski, John Hom

Faculty Publications, Meteorology and Climate Science

Low-intensity wildland fires occurring beneath forest canopies can result in particularly adverse local air-quality conditions. Ambient and fire-induced turbulent circulations play a substantial role in the transport and dispersion of smoke during these fire events. Recent in situ measurements of fire–atmosphere interactions during low-intensity wildland fires have provided new insight into the structure of fire-induced turbulence regimes and how forest overstory vegetation can affect the horizontal and vertical dispersion of smoke. In this paper, we provide a summary of the key turbulence observations made during two low-intensity wildland fire events that occurred in the New Jersey Pine Barrens.

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The Sluggs Survey: Globular Cluster Stellar Population Trends From Weak Absorption Lines In Stacked Spectra, Christopher Usher, Duncan Forbes, Jean Brodie, Aaron Romanowsky, Jay Strader, Charlie Conroy, Caroline Foster, Nicola Pastorello, Vincenzo Pota, Jacob Arnold Jan 2015

The Sluggs Survey: Globular Cluster Stellar Population Trends From Weak Absorption Lines In Stacked Spectra, Christopher Usher, Duncan Forbes, Jean Brodie, Aaron Romanowsky, Jay Strader, Charlie Conroy, Caroline Foster, Nicola Pastorello, Vincenzo Pota, Jacob Arnold

Faculty Publications

As part of the SAGES Legacy Unifying Globulars and GalaxieS (SLUGGS) survey, we stack 1137 Keck DEIMOS (Deep Imaging Multi-Object Spectrograph) spectra of globular clusters from 10 galaxies to study their stellar populations in detail. The stacked spectra have median signal-to-noise ratios of ∼90 Å−1. Besides the calcium triplet, we study weaker sodium, magnesium, titanium and iron lines as well as the Hα and higher order Paschen hydrogen lines. In general, the stacked spectra are consistent with old ages and a Milky Way-like initial mass function. However, we see different metal line index strengths at fixed colour and magnitude, and …

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