485 results on '"Chase, Brian"'
Search Results
152. Amplitude and Phase Controlled Magnetron-Based, RF Source
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Ives, R. Lawrence, primary, Read, Michael, additional, Bui, Thuc, additional, Marsden, David, additional, Collins, George, additional, Chase, Brian, additional, Pasquinelli, Ralph, additional, Walker, Chris, additional, and Conant, Jeff, additional
- Published
- 2017
- Full Text
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153. Advanced, phase-locked, 100 kW, 1.3 GHz magnetron
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Read, Michael, primary, Ives, R. Lawrence, additional, Bui, Thuc, additional, Chase, Brian, additional, Pasquinelli, Ralph, additional, Walker, Chris, additional, and Conant, Jeff, additional
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- 2017
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154. Qualitative assessment of PMIP3 rainfall simulations across the eastern African monsoon domains during the mid-Holocene and the Last Glacial Maximum
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Chevalier, Manuel, primary, Brewer, Simon, additional, and Chase, Brian M., additional
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- 2017
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155. Energy Spread of the Proton Beam in the Fermilab Booster at Its Injection Energy
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Bhat, Chandra, Chase, Brian, Chaurize, Salah, Garcia, Fernanda, Pellico, William, Seiya, Kiyomi, Sullivan, Todd, and Triplett, A. Kent
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4: Hadron Accelerators ,Physics::Accelerator Physics ,Accelerator Physics - Abstract
We have measured the total energy spread (99% energy spread) of the Booster beam at its injection energy of 400 MeV by three different methods - 1) creating a notch of about 40 nsec wide in the beam immediately after multiple turn injection and measuring the slippage time required for high and low momentum particles for a grazing touch in line-charge distribution, 2) injecting partial turn beam and letting it to debunch, and 3) comparing the beam profile monitor data with predictions from MAD simulations for the 400 MeV injection beam line. The measurements are repeated under varieties of conditions of RF systems in the ring and in the beam transfer line., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA
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- 2015
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156. High Gradient Performance in Fermilab ILC Cryomodule
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Harms, Elvin, Baffes, Curtis, Carlson, Kermit, Chase, Brian, Crawford, Darren, Cullerton, Ed, Edstrom, Dean, Hocker, Andy, Klebaner, Arkadiy, Kucera, Michael, Leibfritz, Jerry, Makara, Jerry, McDowell, Dave, Nezhevenko, Oleg, Nicklaus, Dennis, Pischalnikov, Yuriy, Prieto, Peter, Reid, John, Schappert, Warren, Soyars, William, Varghese, Philip, and Warner, Arden
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SRF Technology - Cryomodule ,Accelerator Physics - Abstract
Fermilab has assembled an ILC like cryomodule using U.S. processed high gradient cavities and achieved an average gradient of 31.5 MV/m for the entire cryomodule. Test results and challenges along the way will be discussed., Proceedings of the 17th International Conference on RF Superconductivity, SRF2015, Whistler, BC, Canada
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- 2015
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157. Integrated High-Power Tests of Dressed N-doped 1.3 GHz SRF Cavities for LCLS-II
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Solyak, Nikolay, Arkan, Tug, Chase, Brian, Crawford, Anthony, Cullerton, Ed, Gonin, Ivan, Grassellino, Anna, Grimm, Chuck, Hocker, Andy, Holzbauer, Jeremiah, Khabiboulline, Timergali, Melnychuk, Oleksandr, Ozelis, Joseph, Peterson, Thomas, Pischalnikov, Yuriy, Premo, Ken, Romanenko, Alexander, Rowe, Allan, Schappert, Warren, Sergatskov, Dmitri, Stanek, Richard, and Wu, Genfa
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SRF Technology - Cavity ,Accelerator Physics - Abstract
New auxiliary components have been designed and fabricated for the 1.3 GHz SRF cavities comprising the LCLS-II linac. In particular, the LCLS-II cavity’s helium vessel, high-power input coupler, higher-order mode (HOM) feedthroughs, magnetic shielding, and cavity tuning system were all designed to meet LCLS-II specifications. Integrated tests of the cavity and these components were done at Fermilab’s Horizontal Test Stand (HTS) using several kilowatts of continuous-wave (CW) RF power. The results of the tests are summarized here., Proceedings of the 17th International Conference on RF Superconductivity, SRF2015, Whistler, BC, Canada
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- 2015
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158. Initial Experimental Results of a Machine Learning-Based Temperature Control System for an RF Gun
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Edelen, Auralee, Biedron, Sandra, Chase, Brian, Crawford, Darren, Eddy, Nathan, Edstrom, Dean, Harms, Elvin, Milton, Stephen, Ruan, Jinhao, Santucci, James, and Stabile, Pierpaolo
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6: Beam Instrumentation, Controls, Feedback, and Operational Aspects ,Accelerator Physics - Abstract
Colorado State University (CSU) and Fermi National Accelerator Laboratory (Fermilab) have been developing a control system to regulate the resonant frequency of an RF electron gun. As part of this effort, we present experimental results for a benchmark temperature controller that combines a machine learning-based model and a predictive control algorithm for improved settling time, overshoot, and disturbance rejection relative to conventional techniques. Such improvements have implications for machine up-time and management of reflected power. This work is part of an on-going effort to develop adaptive, machine learning-based tools specifically to address control challenges found in particle accelerator systems., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA
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- 2015
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159. Corrigendum: Continental-scale temperature variability during the past two millennia
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Ljungqvist, Fredrik C., McConnell, Joseph R., McKay, Nicholas P., Curran, Mark A. J., Shao, Xuemei, Severi, Mirko, Shanahan, Timothy M., Palmer, Jonathan G., Masson-Delmotte, Valérie, Korhola, Atte A., Diaz, Henry F., Gergis, Joëlle, Borgaonkar, Hemant P., Kimura, Katsuhiko, Van Ommen, Tas, Steig, Eric J., Grab, Stefan W., Chase, Brian M., Lara, Antonio, Stenni, Barbara, Von Gunten, Lucien, Trouet, Valerie, Gaire, Narayan P., Turney, Chris S.M., Wagner, Sebastian, Vinther, Bo M., Goosse, Hugues, Sano, Masaki, Christie, Duncan A., Morales, Mariano S., Phipps, Steven J., Fan, Ze-Xin, Moy, Andrew D., Nash, David J., Wanner, Heinz, Lorrey, Andrew M., Esper, Jan, Kaufman, Darrell S., Smerdon, Jason E., Verschuren, Dirk, González-Rouco, J Fidel, Graham, Nicholas, Viau, Andre E., Yasue, Koh, Cook, Edward R., Lézine, Anne-Marie, Villalba, Ricardo, Anchukaitis, Kevin J., Graham, Rochelle, Wahl, Eugene R., Krusic, Paul J., Luterbacher, Jürg, Braida, Martina, Solomina, Olga N., Sigl, Michael, Umer, Mohammed, White, James W.C., Kiefer, Thorsten, Rivera, Andres, Büntgen, Ulf, Mundo, Ignacio A., Prieto, Maria R., Oerter, Hans, Hanhijärvi, Sami T., Ahmed, Moinuddin, Ge, Quansheng, Buckley, Brendan M., Werner, Johannes P., Grosjean, Martin, Shi, Feng, Nicholson, Sharon E., Zorita, Eduardo, Nakatsuka, Takeshi, Asrat, Asfawossen, Mulvaney, Robert, Thamban, Meloth, McCarroll, Danny, and Neukom, Raphael
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550 Earth sciences & geology ,910 Geography & travel - Published
- 2015
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160. The LCLS-II LLRF System
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Hovater, Curt, Babel, Sandeep, Bachimanchi, Ramakrishna, Chase, Brian, Cullerton, Ed, Doolittle, Lawrence, Hong, Bo, Huang, Gang, Ratti, Alessandro, Serrano, Carlos, Van Winkle, Daniel, and Varghese, Philip
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6: Beam Instrumentation, Controls, Feedback, and Operational Aspects ,Accelerator Physics - Abstract
The SLAC National Accelerator Laboratory is planning an upgrade (LCLS-II) to the Linear Coherent Light Source with a 4 GeV CW superconducting (SCRF) linac. The SCRF linac consists of 35 ILC style cryomodules (eight cavities each) for a total of 280 cavities. Expected cavity gradients are 16 MV/m with a loaded QL of ~ 4x10⁷. The RF system will have 3.8 kW solid state amplifiers driving single cavities. To ensure optimum field stability a single source single cavity control system has been chosen. It consists of a precision four channel cavity receiver and RF stations (Forward, Reflected and Drive signals). In order to regulate the resonant frequency variations of the cavities due to He pressure, the tuning of each cavity is controlled by a Piezo actuator and a slow stepper motor. In addition the system (LLRF-amplifier-cavity) is being modeled and cavity microphonic testing has started. This paper describes the LLRF system under consideration, including recent modeling and cavity tests., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA
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- 2015
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161. High-Power Magnetron Transmitter for the Electron Collider Ring of the MEIC Facility
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Kazakevich, Grigory, Chase, Brian, Derbenev, Yaroslav, and Yakovlev, Vyacheslav
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7: Accelerator Technology ,Accelerator Physics - Abstract
Operation of the 3-12 GeV electron collider 8-shape ring of the MEIC facility causes a Synchrotron Radiation (SR) of electrons in arcs with energy loss of ~20 kW/m at beam current of ~3 A. The total SR loss up to 2 MW per a revolution is presumed to compensate by Superconducting RF (SRF) accelerating cavities. To minimize the beam emittance, each individual SRF cavity is proposed to feed by an individual and independent RF source allowing a wide-band control in phase and power. Most efficient and less expensive in capital and maintenance costs the high-power transmitters based on magnetrons, injection-locked by phase-modulated signals, controlled in wide-band are proposed as the RF sources. The magnetron RF sources utilizing 2-cascade magnetrons allowing a wide-band phase and power control by the injection-locking phase-modulated signals were experimentally modelled by 2.45 GHz, CW, 1 kW magnetrons. Results of the modelling and adequacy of the transmitters for the SRF cavities are discussed in the presented article., Proceedings of the 6th Int. Particle Accelerator Conf., IPAC2015, Richmond, VA, USA
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- 2015
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162. SRF, Compact Accelerators for Industry & Society
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Kephart, Robert, Biedron, Sandra, Chase, Brian, Chattopadhyay, Swapan, Gonin, Ivan, Grassellino, Anna, Kazakov, Sergey, Khabiboulline, Timergali, Milton, Stephen, Nagaitsev, Sergei, Pasquinelli, Ralph, Piot, Philippe, Posen, Sam, Pronitchev, Oleg, Romanenko, Alexander, Sipahi, Nihan, and Yakovlev, Vyacheslav
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New Proposals ,Accelerator Physics - Abstract
Accelerators developed for Science now are used broadly for industrial, medical, and security applications. Over 30,000 accelerators touch over $500B/yr in products producing a major impact on our economy, health, and well being. Industrial accelerators must be cost effective, simple, versatile, efficient, and robust. Many industrial applications require high average beam power. Exploiting recent advances in Superconducting Radio Frequency (SRF) cavities and RF power sources as well as innovative solutions for the SRF gun and cathode system, a collaboration of Fermilab-CSU-NIU has developed a design for a compact SRF high-average power electron linac. Capable of 5-50 kW average power and continuous wave operation this accelerator will produce electron beam energies up to 10 MeV and small and light enough to mount on mobile platforms, such accelerators will enable new in-situ environmental remediation methods and new applications involving in-situ crosslinking of materials. More importantly, we believe this accelerator will be the first of a new class of simple, turn-key SRF accelerators that will find broad application in industry, medicine, security, and science., Proceedings of the 17th International Conference on RF Superconductivity, SRF2015, Whistler, BC, Canada
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- 2015
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163. Fermilab Cryomodule Test Stand Design and Plans
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Harms, Elvin, Baffes, Curtis, Carlson, Kermit, Chase, Brian, Klebaner, Arkadiy, Kucera, Michael, Leibfritz, Jerry, McGee, Mike, Prieto, Peter, Reid, John, Stanek, Richard, Sun, Ding, and White, Michael
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Projects/Facilities - progress ,Accelerator Physics - Abstract
A facility dedicated to SRF cryomodule testing is under construction at Fermilab. The test stand has been designed to be flexible enough to cool down and power test full length TESLA-style 8-cavity cryomodules as well cryomodules for low-β acceleration. We describe the design considerations, status, and near future plans for utilization of the test stand., Proceedings of the 17th International Conference on RF Superconductivity, SRF2015, Whistler, BC, Canada
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- 2015
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164. Late Quaternary micromammals and the precipitation history of the southern Cape, South Africa.
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Faith, J. Tyler, Chase, Brian M., and Avery, D. Margaret
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LAST Glacial Maximum , *METEOROLOGICAL precipitation , *BARN owl , *RAINFALL , *CAVES - Abstract
The southern Cape of South Africa is important to understanding regional climate because it straddles the transition between the winter and summer rainfall zones. We examine late Quaternary changes in rainfall seasonality and aridity through analysis of micromammal assemblages from three sites: Boomplaas Cave and Nelson Bay Cave in the aseasonal rainfall zone and Byneskranskop 1 in the winter rainfall zone. Our interpretation is based on analysis of 123 modern micromammal assemblages accumulated by barn owls (Tyto alba), which empirically links species composition to climate. The Pleistocene record (∼65 to 12 ka) from Boomplaas Cave, together with the last glacial maximum (LGM) samples from Nelson Bay Cave, indicates enhanced winter rainfall, especially during the LGM. Boomplaas Cave documents progressive aridification from the LGM to the earliest Holocene, followed by a return to moderately humid conditions through the Holocene. Byneskranskop 1 indicates a dominance of winter rains over the last 17 ka and a shift from an arid middle Holocene to a humid later Holocene. Agreement between the micromammal record and other local and regional proxies reinforces the potential of southern African micromammal assemblages as paleoclimate indicators. [ABSTRACT FROM AUTHOR]
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- 2019
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165. Mid to late quaternary landscape and environmental dynamics in the Middle Stone Age of southern South Africa
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Carr, Andrew S, Chase, Brian M, Mackay, Alex, Carr, Andrew S, Chase, Brian M, and Mackay, Alex
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The southern Cape of South Africa hosts a remarkably rich Middle Stone Age (MSA) archaeological record. Many of the associated caves and rock shelters are coastal sites, which contain evidence for varied occupational intensity and marine resource use, along with signs of notable landscape, environmental, and ecological change. Here, we review and synthesize evidence for Quaternary landscape and climatic change of relevance to the southern Cape MSA. We seek to highlight the available data of most relevance to the analysis and interpretation of the region's archaeological record, as well as critical data that are lacking. The southern Cape MSA occupation spans the full range of glacial-interglacial conditions (i.e., 170-55 ka). It witnessed marked changes in coastal landscape dynamics, which although driven largely by global eustatic sea level changes, were modulated by local-scale, often inherited, geological constraints. These prevent simple extrapolations and generalizations concerning paleolandscape change. Such changes, including pulses of coastal dune activity, will have directly influenced resource availability around the region's archaeological sites. Evidence for paleoclimatic change is apparent, but it is scarce and difficult to interpret. It is likely, however that due to the same diversity of rainfall sources influencing the region today, compared to parts of the continental interior, the southern Cape climate was relatively equable throughout the last 150 kyr. The region's paleoecology, particularly in relation to the coastal plains exposed during sea level lowstands, is a key element missing in attempts to synthesize and model the resources available to occupants of this region. Technology, settlement, and subsistence probably changed in response to these paleoclimate/landscape adjustments, but improvements in baseline archaeological and paleoenvironmental data are required to strengthen models of ecosystem variation and human behavioral response through
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- 2016
166. The spatial extent and dynamics of the Antarctic Cold Reversal
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Pedro, Joel Benjamin, Bostock, Helen C., Bitz, Cecilia M., He, Feng, Vandergoes, Marcus J., Steig, Eric J., Chase, Brian M., Krause, Claire E., Rasmussen, Sune Olander, Markle, Bradley R., Cortese, Giuseppe, Pedro, Joel Benjamin, Bostock, Helen C., Bitz, Cecilia M., He, Feng, Vandergoes, Marcus J., Steig, Eric J., Chase, Brian M., Krause, Claire E., Rasmussen, Sune Olander, Markle, Bradley R., and Cortese, Giuseppe
- Published
- 2016
167. Comment
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URQUHART, DJ, HUDSON, WS, SCOTT, AD, CHASE, BRIAN, SULLIVAN, RENE, FLETCHER, JOHN, and JFWB
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- 1975
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168. Commissioning Status of the Advanced Superconducting Test Accelerator at Fermilab
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Ruan, Jinhao, Andrews, Richard, Baffes, Curtis, Broemmelsiek, Daniel, Carlson, Kermit, Chase, Brian, Church, Michael, Crawford, Darren, Cullerton, Ed, Diamond, John, Eddy, Nathan, Edstrom, Dean, Harms, Elvin, Hocker, Andy, Johnson, Amber, Klebaner, Arkadiy, Kucera, Michael, Leibfritz, Jerry, Lumpkin, Alex, Makara, Jerry, Nagaitsev, Sergei, Nezhevenko, Oleg, Nicklaus, Dennis, Nobrega, Lucy, Piot, Philippe, Prieto, Peter, Reid, John, Santucci, James, Stancari, Giulio, Sun, Ding, Wendt, Manfred, and Wesseln, Steven
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T07 Superconducting RF ,Accelerator Physics ,07 Accelerator Technology Main Systems - Abstract
The Advanced Superconducting Test Accelerator (ASTA) is under construction at Fermilab. This accelerator will consist of a photo-electron gun, injector, ILC-type cryomodules, and multiple downstream beam-lines. Its purpose is to be a user-based facility for Advanced Accelerator R&D. . Following the successful commissioning of the photoinjector gun, a Tesla style 8-cavity cryomodule and a high gradient capture cavity have been cooled down to 2 K and powered commissioning and performance characterization has begun. We will report on the commissioning status and near-term future plans for the facility., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany
- Published
- 2014
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169. SRF Systems for ASTA at Fermilab
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Harms, Elvin, Baffes, Curtis, Carlson, Kermit, Chase, Brian, Crawford, Darren, Cullerton, Ed, Edstrom, Dean, Geynisman, Michael, Hocker, Andy, Klebaner, Arkadiy, Kucera, Michael, Leibfritz, Jerry, Makara, Jerry, McDowell, Dave, Nagaitsev, Sergei, Nezhevenko, Oleg, Nicklaus, Dennis, Pfeffer, Howard, Pischalnikov, Yuriy, Prieto, Peter, Reid, John, Schappert, Warren, Stabile, Pierpaolo, and Varghese, Philip
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T07 Superconducting RF ,Accelerator Physics ,07 Accelerator Technology Main Systems - Abstract
The Advanced Superconducting Test Accelerator (ASTA) at Fermilab now being commissioned is comprised of a number of superconducting RF systems including single-cavity cryomodules and a TESLA/ILC style 8-cavity cryomodule. Two of them, 'Capture Cavity 2' and 'Cryomodule 2', have been cooled to 2 Kelvin and brought into operation. We provide an overview of the unique characteristics of each of the systems, commissioning experience, and latest results including their respective operating characteristics., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany
- Published
- 2014
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170. Results from RF Tests of the First US-built High-gradient Superconducting Cryomodule
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Hocker, Andy, Baffes, Curtis, Carlson, Kermit, Chase, Brian, Crawford, Darren, Cullerton, Ed, Edstrom, Dean, Harms, Elvin, Kubicki, Tom, Kucera, Michael, Leibfritz, Jerry, Makara, Jerry, McDowell, Dave, Nezhevenko, Oleg, Nicklaus, Dennis, Pfeffer, Howard, Pischalnikov, Yuriy, Prieto, Peter, Reid, John, Schappert, Warren, Stabile, Pierpaolo, and Varghese, Philip
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T07 Superconducting RF ,Accelerator Physics ,07 Accelerator Technology Main Systems - Abstract
Fermilab has built a cryomodule comprised of eight 1.3 GHz superconducting RF cavities for use in its Advanced Superconducting Test Accelerator (ASTA) facility. This cryomodule (RFCA002) was intended to achieve the International Linear Collider (ILC) “S1” goal of demonstrating an average accelerating gradient of 31.5 MV/m, and is the first of its kind built in the United States. The module has been cooled down and operated without beam at ASTA in order to assess its performance. The results from these tests are presented here., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany
- Published
- 2014
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171. Holocene climate change in southernmost South Africa: rock hyrax middens record shifts in the southern westerlies
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Chase, Brian M., Boom, Arnoud, Carr, Andrew S., Meadows, Michael E., and Reimer, Paula J.
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- 2013
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172. POLLEN RECORDS, LATE PLEISTOCENE | Africa
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Meadows, M.E., Chase, Brian M., Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), and Chase, Brian
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[SDE.BE] Environmental Sciences/Biodiversity and Ecology ,[SDE.MCG] Environmental Sciences/Global Changes ,[SDE.MCG]Environmental Sciences/Global Changes ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,[SDU.ENVI] Sciences of the Universe [physics]/Continental interfaces, environment ,ComputingMilieux_MISCELLANEOUS - Abstract
International audience
- Published
- 2007
173. The African Quaternary: Environments, ecology and humans inaugural AFQUA conference
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Chase, Brian M., primary, Quick, Lynne J., additional, and Kirsten, Kelly L., additional
- Published
- 2016
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174. Advanced, phase-locked, 100 kW, 1.3 GHz magnetron
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Read, Michael, primary, Ives, R. Lawrence, additional, Bui, Thuc, additional, Pasquinelli, Ralph, additional, Chase, Brian, additional, Walker, Chris, additional, and Conant, Jeff, additional
- Published
- 2016
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175. Advanced, Phase-Locked, 100 kW, 1.3 GHz Magnetron.
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Read, Michael, Ives, R. Lawrence, Bui, Thuc, Pasquinelli, Ralph, Chase, Brian, Walker, Chris, and Conant, Jeff
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MAGNETRONS ,MODE-locked lasers ,PARTICLE accelerators - Abstract
Calabazas Creek Research, Inc., in collaboration with Fermilab and Communications & Power Industries, LLC, is developing a phase-locked, 100 kW peak, 10 kW average power magnetron-based RF system for driving accelerators. Phase locking will be achieved using an approach originating at Fermilab that includes control of both amplitude and phase on a fast time scale. [ABSTRACT FROM AUTHOR]
- Published
- 2017
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176. The spatial extent and dynamics of the Antarctic Cold Reversal
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Pedro, Joel B., primary, Bostock, Helen C., additional, Bitz, Cecilia M., additional, He, Feng, additional, Vandergoes, Marcus J., additional, Steig, Eric J., additional, Chase, Brian M., additional, Krause, Claire E., additional, Rasmussen, Sune O., additional, Markle, Bradley R., additional, and Cortese, Giuseppe, additional
- Published
- 2015
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177. Temperature variability over Africa during the last 2000 years
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Chase , Brian, Nicholson , Sharon, Nash , David, Grab , Stefan, Shanahan , Timothy, Verschuren , Dirk, Asrat , Asfawossen, Lézine , Anne-Marie, Umer , Mohammed, Florida State University [Tallahassee] ( FSU ), School of Environment and Technology, University of Brighton, University of the Witwatersrand [Johannesburg] ( WITS ), Institut des Sciences de l'Evolution de Montpellier ( ISEM ), Université de Montpellier ( UM ) -Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique ( CNRS ), University of Bergen ( UIB ), University of Texas at Austin [Austin], Ghent University [Belgium] ( UGENT ), Addis Ababa University ( AAU ), Université Pierre et Marie Curie - Paris 6 - UFR de Médecine Pierre et Marie Curie ( UPMC ), Université Pierre et Marie Curie - Paris 6 ( UPMC ), Université Henri Poincaré - Nancy 1 ( UHP ), Laboratoire de Géologie du Quaternaire ( LGQ ), and Centre National de la Recherche Scientifique ( CNRS ) -Université de la Méditerranée - Aix-Marseille 2
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[ SDE.MCG ] Environmental Sciences/Global Changes - Abstract
International audience; A growing number of proxy, historical and instrumental data sets are now available from continental Africa through which past variations in temperaturecan be assessed. This paper, co-authored by members of the PAGES Africa2k Working Group, synthesises published material to produce a record oftemperature variability for Africa as a whole spanning the last 2000 years. The paper focuses on temperature variability during the ‘Medieval ClimateAnomaly’ (MCA), ‘Little Ice Age’ (LIA) and late 19th–early 21st centuries. Warmer conditions during the MCA are evident in records from LakeTanganyika in central Africa, the Ethiopian Highlands in northeastern Africa, and Cango Cave, the Kuiseb River and Wonderkrater in southern Africa.Other records covering the MCA give ambiguous signals. Warming appears to have been greater during the early MCA (c. ad 1000) in parts of southernAfrica and during the later MCA (from ad 1100) in Namibia, Ethiopia and at Lake Tanganyika. LIA cooling is evident in Ethiopian and southern Africanpollen records and in organic biomarker data from Lake Malawi in southeastern tropical Africa, while at Lake Tanganyika the temperature depressionappears to have been less consistent. A warming trend in mean annual temperatures is clearly evident from historical and instrumental data coveringthe late 19th to early 21st centuries. General warming has occurred over Africa since the 1880s punctuated only by a period of cooling in the mid 20thcentury. The rate of temperature increase appears to have accelerated towards the end of the 20th century. The few long high-resolution proxy recordsthat extend into the late 20th century indicate that average annual temperatures were 1–2°C higher in the last few decades than during the MCA.
- Published
- 2013
178. Reconstructing past upwelling intensity and the seasonal dynamics of primary productivity along the Peruvian coastline from mollusk shell stable isotopes
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Sadler, James, Carré, Matthieu, Azzoug, Moufok, Schauer, Andrew J., Ledesma, Jesus, Cardenas, Fredy, Chase, Brian M., Bentaleb, Ilhem, Muller, Serge D., Mandeng Yogo, Magloire, Rohling, Eelco J., Sachs, Julian P., National Oceanography Centre [Southampton] (NOC), University of Southampton, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École Pratique des Hautes Études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Department of Earth and Space Sciences [Seattle], University of Washington [Seattle], Instituto del Mar del Peru (IMARPE), Paléoclimats, proxies, processus (PALEOPROXUS), Laboratoire d'Océanographie et du Climat : Expérimentations et Approches Numériques (LOCEAN), Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS-PSL), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Muséum national d'Histoire naturelle (MNHN)-Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), School of Oceanography [Seattle], Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636)), École normale supérieure - Paris (ENS Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-École normale supérieure - Paris (ENS Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-École polytechnique (X)-Centre National d'Études Spatiales [Toulouse] (CNES)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Muséum national d'Histoire naturelle (MNHN)-Institut Pierre-Simon-Laplace (IPSL (FR_636))
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[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph] ,[SDE.MCG]Environmental Sciences/Global Changes ,[PHYS.PHYS.PHYS-GEO-PH]Physics [physics]/Physics [physics]/Geophysics [physics.geo-ph] - Abstract
International audience; We present here a potential new method to evaluate past variations of the mean intensity of Peruvian coastal upwelling and of the seasonal timing of phytoplankton blooms. This method uses a combination of the monthly carbon and oxygen isotopic signals preserved in fossil mollusk shells, and a series of corrections to extract the variations of the dissolved inorganic carbon (DIC) δ13C. Based on the analysis of five shell samples (85 shells in total) from the southern Peruvian coast, we suggest that the mean coastal upwelling intensity can be determined from a linear relationship between average values of corrected shell δ13C and δ18O. This new potential proxy would bring additional independent information valuable to interpret paleoproductivity changes reconstructed from marine sediment of the nearby continental shelf. Results obtained on fossil samples from the middle Holocene show an increase in upwelling intensity during this period associated to a spatial reorganization of upwelling centers along the South Peruvian coast. At the seasonal scale, corrected shell δ13C enrichment indicates a phytoplankton bloom. Seasonal timing of phytoplankton blooms can be estimated by the lag with the annual temperature cycle reproduced by shell δ18O monthly variations. The results obtained with two modern shell samples indicate phytoplankton blooms occurring during summer and fall, consistently with in situ productivity observations. Our method relies on revisited assumptions about the influence of temperature and metabolism in mollusk shell δ13C. We further discussed the validity of these assumptions and the potential implications for the interpretation of similar data sets.
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- 2012
179. A 19.5kyr vegetation history from the central Cederberg Mountains, South Africa: Palynological evidence from rock hyrax middens
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Sadler, James, Carré, Matthieu, Azzoug, Moufok, Schauer, Andrew, Ledesma, Jesus, Cardenas, Fredy, Bentaleb, Ilham, Muller, Serge, Mandeng, Magloire, Rohling, Eelco, Sachs, Julian, Quick, Lynne, Chase, Brian, Meadows, Michael, Scott, Louis, REIMER, Paula, Institut des Sciences de l'Evolution de Montpellier (UMR ISEM), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Montpellier (UM)-Institut de recherche pour le développement [IRD] : UR226-Centre National de la Recherche Scientifique (CNRS), Département de Génie des procédés, Université Hassiba Ben Bouali de Chlef (UHBC), Instituto del Mar del Peru (IMARPE), Laboratoire Biodiversité et Fonctionnement des Ecosystèmes (LBFE), Université Paul Verlaine - Metz (UPVM), Ocean and Earth Science [Southampton], University of Southampton-National Oceanography Centre (NOC), University of Cape Town, and University of Bristol [Bristol]
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010506 paleontology ,010504 meteorology & atmospheric sciences ,[SDE.MCG]Environmental Sciences/Global Changes ,Oceanography ,01 natural sciences ,Rock hyrax ,Glacial period ,[SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces, environment ,Ecology, Evolution, Behavior and Systematics ,Holocene ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences ,Earth-Surface Processes ,Palynology ,biology ,Ecology ,Paleontology ,Vegetation ,15. Life on land ,biology.organism_classification ,Arid ,Midden ,13. Climate action ,Interglacial ,[SDE.BE]Environmental Sciences/Biodiversity and Ecology ,Geology - Abstract
In arid and semi-arid areas such as southern Africa, rock hyrax ( Procavia capensis ) middens represent an exceptionally valuable source of late Quaternary palaeoenvironmental information. Pollen and stable isotope data derived from two rock hyrax middens extracted from De Rif in the Cederberg Mountains of the southwestern Cape, casts new light on climatic changes that occurred across the Last Glacial–Interglacial Transition (LGIT) and the Holocene (19.5–0.7 cal kBP) and how the region's vegetation responded to these changes. Significant changes in vegetation community composition would be expected in response to environmental changes characteristic of the contrast between ‘glacial’ and ‘interglacial’ climates. However, the pollen assemblages in general indicate that mountain fynbos remained dominant throughout the record and that most of the pollen taxa exhibited only muted frequency variations. This finding could be considered to be inconsistent with indications of marked climatic variations recorded in the stable isotope records for the same midden. An analysis of the geological setting and the bioclimatic affinities of the taxa suggest that the explanation for this inconsistency may lie in the dominating influence of sandstone substrates and the relative resilience of mountain fynbos vegetation to climate change.
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- 2011
180. Starting On the Ground Floor
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CHASE, BRIAN and WHITE, PETER Z.
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United States. General Services Administration -- Contracts ,Portland State University -- Buildings and facilities ,Universities and colleges -- Arizona -- Oregon ,Business ,Petroleum, energy and mining industries ,Contract agreement ,Buildings and facilities ,Contracts - Abstract
Brian Chase is director of facilities at Portland State University in Portland, Ore. Peter Z. White is an account executive with the Portland, Ore., branch of the Controls Group of [...]
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- 1999
181. Coalescence and fragmentation in the late Pleistocene archaeology of southernmost Africa
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Mackay, Alex, Stewart, Brian A, Chase, Brian M, Mackay, Alex, Stewart, Brian A, and Chase, Brian M
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The later Pleistocene archaeological record of southernmost Africa encompasses several Middle Stone Age industries and the transition to the Later Stone Age. Through this period various signs of complex human behaviour appear episodically, including elaborate lithic technologies, osseous technologies, ornaments, motifs and abstract designs. Here we explore the regional archaeological record using different components of lithic technological systems to track the transmission of cultural information and the extent of population interaction within and between different climatic regions. The data suggest a complex set of coalescent and fragmented relationships between populations in different climate regions through the late Pleistocene, with maximum interaction (coalescence) during MIS 4 and MIS 2, and fragmentation during MIS 5 and MIS 3. Coalescent phases correlate with increases in the frequency of ornaments and other forms of symbolic expression, leading us to suggest that population interaction was a significant driver in their appearance.
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- 2014
182. Precision Vector Control of a Superconducting RF Cavity driven by an Injection Locked Magnetron
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Chase, Brian, Pasquinelli, Ralph, Cullerton, Ed, Varghese, Philip, Chase, Brian, Pasquinelli, Ralph, Cullerton, Ed, and Varghese, Philip
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The technique presented in this paper enables the regulation of both radio frequency amplitude and phase in narrow band devices such as a Superconducting RF (SRF) cavity driven by constant power output devices i.e. magnetrons. The ability to use low cost high efficiency magnetrons for accelerator RF power systems, with tight vector regulation, presents a substantial cost savings in both construction and operating costs compared to current RF power system technology. An operating CW system at 2.45 GHz has been experimentally developed. Vector control of an injection locked magnetron has been extensively tested and characterized with a SRF cavity as the load. Amplitude dynamic range of 30 dB, amplitude stability of 0.3% r.m.s, and phase stability of 0.26 degrees r.m.s. has been demonstrated.
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- 2014
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183. Mid to Late Quaternary Landscape and Environmental Dynamics in the Middle Stone Age of Southern South Africa.
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Carr, Andrew S., Chase, Brian M., and Mackay, Alex
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- 2016
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184. Stable isotope analyses of rock hyrax faecal pellets, hyraceum and associated vegetation in southern Africa: Implications for dietary ecology and palaeoenvironmental reconstructions.
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Carr, Andrew S., Chase, Brian M., Boom, Arnoud, and Medina-Sanchez, Javier
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ROCK hyrax , *FOLIAGE plants , *FECES , *GRAZING , *NITROGEN isotopes - Abstract
Rock hyrax middens are important palaeoenvironmental archives in southern Africa. Carbon and nitrogen isotope measurements on middens (hyraceum) are key components of climate reconstructions, but their interpretations require refinement. Although δ 15 N in hyraceum often correlates with independent proxies for palaeo-aridity, the impacts of dietary and physiological controls on hyraceum δ 15 N remain to be resolved. We analyse δ 13 C and δ 15 N in plant foliage, hyrax faecal pellets and hyraceum from 21 sites across southern Africa. Faeces are generally depleted in 13 C (δ 13 C typically < −20‰), suggesting significant browsing. Grazing is rarely dominant and probably occurs only when palatable grass is available. Variability in faecal and foliar δ 15 N is large, but foliar δ 15 N is positively correlated with faecal δ 15 N. The diet-faeces δ 15 N offset is uncorrelated with climate (aridity), but is correlated with %N in faeces. Faecal δ 15 N is positively correlated with modern hyraceum δ 15 N, and the relationships with aridity index for foliar and faecal (body tissue) δ 15 N are comparable. These observations implicate diet as a significant control on hyraceum δ 15 N and we observe no strong evidence for metabolic controls on hyraceum δ 15 N. More data are required to refine these relationships, but these observations are consistent with current palaeoenvironmental interpretations of midden δ 15 N and δ 13 C. [ABSTRACT FROM AUTHOR]
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- 2016
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185. High-power magnetron transmitter as an RF source for superconducting linear accelerators
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Kazakevich, Grigory, primary, Johnson, Rolland, additional, Flanagan, Gene, additional, Marhauser, Frank, additional, Yakovlev, Vyacheslav, additional, Chase, Brian, additional, Lebedev, Valeri, additional, Nagaitsev, Sergei, additional, Pasquinelli, Ralph, additional, Solyak, Nikolay, additional, Quinn, Kenneth, additional, Wolff, Daniel, additional, and Pavlov, Viatcheslav, additional
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- 2014
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186. Coalescence and fragmentation in the late Pleistocene archaeology of southernmost Africa
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Mackay, Alex, primary, Stewart, Brian A., additional, and Chase, Brian M., additional
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- 2014
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187. Leaf wax n-alkane distributions in arid zone South African flora: Environmental controls, chemotaxonomy and palaeoecological implications
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Carr, Andrew S., primary, Boom, Arnoud, additional, Grimes, Hannah L., additional, Chase, Brian M., additional, Meadows, Michael E., additional, and Harris, Angela, additional
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- 2014
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188. Continental-scale temperature variability during the past two millennia
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UCL - SST/ELI/ELIC - Earth & Climate, Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant P., Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A. J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J Fidel, Goosse, Hugues, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valérie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, Zorita, Eduardo, UCL - SST/ELI/ELIC - Earth & Climate, Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant P., Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A. J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J Fidel, Goosse, Hugues, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valérie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, and Zorita, Eduardo
- Abstract
Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
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- 2013
189. Continental-scale temperature variability during the past two millennia
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PAGES-2k-Network, Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant, Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A. J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J Fidel, Goosse, Hueghes, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valerie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, Van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, Zorita, Eduardo, PAGES-2k-Network, Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant, Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A. J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J Fidel, Goosse, Hueghes, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valerie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, Van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, and Zorita, Eduardo
- Abstract
Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
- Published
- 2013
190. Continental-scale temperature variability during the past two millennia
- Author
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Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant P., Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A.J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J. Fidel, Goosse, Hugues, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valérie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, Zorita, Eduardo, Ahmed, Moinuddin, Anchukaitis, Kevin J., Asrat, Asfawossen, Borgaonkar, Hemant P., Braida, Martina, Buckley, Brendan M., Büntgen, Ulf, Chase, Brian M., Christie, Duncan A., Cook, Edward R., Curran, Mark A.J., Diaz, Henry F., Esper, Jan, Fan, Ze-Xin, Gaire, Narayan P., Ge, Quansheng, Gergis, Joëlle, González-Rouco, J. Fidel, Goosse, Hugues, Grab, Stefan W., Graham, Nicholas, Graham, Rochelle, Grosjean, Martin, Hanhijärvi, Sami T., Kaufman, Darrell S., Kiefer, Thorsten, Kimura, Katsuhiko, Korhola, Atte A., Krusic, Paul J., Lara, Antonio, Lézine, Anne-Marie, Ljungqvist, Fredrik C., Lorrey, Andrew M., Luterbacher, Jürg, Masson-Delmotte, Valérie, McCarroll, Danny, McConnell, Joseph R., McKay, Nicholas P., Morales, Mariano S., Moy, Andrew D., Mulvaney, Robert, Mundo, Ignacio A., Nakatsuka, Takeshi, Nash, David J., Neukom, Raphael, Nicholson, Sharon E., Oerter, Hans, Palmer, Jonathan G., Phipps, Steven J., Prieto, Maria R., Rivera, Andres, Sano, Masaki, Severi, Mirko, Shanahan, Timothy M., Shao, Xuemei, Shi, Feng, Sigl, Michael, Smerdon, Jason E., Solomina, Olga N., Steig, Eric J., Stenni, Barbara, Thamban, Meloth, Trouet, Valerie, Turney, Chris S.M., Umer, Mohammed, van Ommen, Tas, Verschuren, Dirk, Viau, Andre E., Villalba, Ricardo, Vinther, Bo M., von Gunten, Lucien, Wagner, Sebastian, Wahl, Eugene R., Wanner, Heinz, Werner, Johannes P., White, James W.C., Yasue, Koh, and Zorita, Eduardo
- Abstract
Past global climate changes had strong regional expression. To elucidate their spatio-temporal pattern, we reconstructed past temperatures for seven continental-scale regions during the past one to two millennia. The most coherent feature in nearly all of the regional temperature reconstructions is a long-term cooling trend, which ended late in the nineteenth century. At multi-decadal to centennial scales, temperature variability shows distinctly different regional patterns, with more similarity within each hemisphere than between them. There were no globally synchronous multi-decadal warm or cold intervals that define a worldwide Medieval Warm Period or Little Ice Age, but all reconstructions show generally cold conditions between ad 1580 and 1880, punctuated in some regions by warm decades during the eighteenth century. The transition to these colder conditions occurred earlier in the Arctic, Europe and Asia than in North America or the Southern Hemisphere regions. Recent warming reversed the long-term cooling; during the period ad 1971–2000, the area-weighted average reconstructed temperature was higher than any other time in nearly 1,400 years.
- Published
- 2013
191. High-throughput sequencing of ancient plant and mammal DNA preserved in herbivore middens
- Author
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Murray, Daithi, Pearson, Stuart, Fullagar, Richard, Chase, Brian, Houston, Jayne, Atchison, Jennifer, White, Nicole, Bellgard, Matthew, Clarke, Edward, MacPhail, Mike, Gilbert, M. Thomas, Haile, James, Bunce, Michael, Murray, Daithi, Pearson, Stuart, Fullagar, Richard, Chase, Brian, Houston, Jayne, Atchison, Jennifer, White, Nicole, Bellgard, Matthew, Clarke, Edward, MacPhail, Mike, Gilbert, M. Thomas, Haile, James, and Bunce, Michael
- Published
- 2012
192. High-throughput sequencing of ancient plant and mammal DNA preserved in herbivore middens
- Author
-
Murray, Dáithí C., Pearson, Stuart G., Fullagar, Richard, Chase, Brian M., Houston, Jayne, Atchison, Jennifer, White, Nicole E., Bellgard, Matthew I., Clarke, Edward, Macphail, Mike, Gilbert, Tom, Haile, James Seymour, Bunce, Michael, Murray, Dáithí C., Pearson, Stuart G., Fullagar, Richard, Chase, Brian M., Houston, Jayne, Atchison, Jennifer, White, Nicole E., Bellgard, Matthew I., Clarke, Edward, Macphail, Mike, Gilbert, Tom, Haile, James Seymour, and Bunce, Michael
- Abstract
The study of arid palaeoenvironments is often frustrated by the poor or non-existent preservation of plant and animal material, yet these environments are of considerable environmental importance. The analysis of pollen and macrofossils isolated from herbivore middens has been an invaluable source of information regarding past environments and the nature of ecological fluctuations within arid zones. The application of ancient DNA (aDNA) techniques to hot, arid zone middens remains unexplored. This paper attempts to retrieve and characterise aDNA from four Southern Hemisphere fossil middens; three located in hot, arid regions of Australia and one sample from South Africa's Western Cape province. The middens are dated to between 30,490 (±380) and 710 (±70) cal yr BP. The Brockman Ridge midden in this study is potentially the oldest sample from which aDNA has been successfully extracted in Australia. The application of high-throughput sequencing approaches to profile the biotic remains preserved in midden material has not been attempted to date and this study clearly demonstrates the potential of such a methodology. In addition to the taxa previously detected via macrofossil and palynological analyses, aDNA analysis identified unreported plant and animal taxa, some of which are locally extinct or endemic. The survival and preservation of DNA in hot, arid environments is a complex and poorly understood process that is both sporadic and rare, but the survival of DNA through desiccation may be important. Herbivore middens now present an important source of material for DNA metabarcoding studies of hot, arid palaeoenvironments and can potentially be used to analyse middens in these environments throughout Australia, Africa, the Americas and the Middle East.
- Published
- 2012
193. High-throughput sequencing of ancient plant and mammal DNA preserved in herbivore middens
- Author
-
Murray, Daithi C, Pearson, Stuart G, Fullagar, Richard L, Chase, Brian M, Houston, Jayne, Atchison, Jennifer, White, Nicole E, Bellgard, Matthew I, Clarke, Edward, Macphail, Mike, Gilbert, M. Thomas P, Haile, James, Bunce, Michael, Murray, Daithi C, Pearson, Stuart G, Fullagar, Richard L, Chase, Brian M, Houston, Jayne, Atchison, Jennifer, White, Nicole E, Bellgard, Matthew I, Clarke, Edward, Macphail, Mike, Gilbert, M. Thomas P, Haile, James, and Bunce, Michael
- Abstract
The study of arid palaeoenvironments is often frustrated by the poor or non-existent preservation of plant and animal material, yet these environments are of considerable environmental importance. The analysis of pollen and macrofossils isolated from herbivore middens has been an invaluable source of information regarding past environments and the nature of ecological fluctuations within arid zones. The application of ancient DNA (aDNA) techniques to hot, arid zone middens remains unexplored. This paper attempts to retrieve and characterise aDNA from four Southern Hemisphere fossil middens; three located in hot, arid regions of Australia and one sample from South Africa's Western Cape province. The middens are dated to between 30,490 (±380) and 710 (±70) cal yr BP. The Brockman Ridge midden in this study is potentially the oldest sample from which aDNA has been successfully extracted in Australia. The application of high-throughput sequencing approaches to profile the biotic remains preserved in midden material has not been attempted to date and this study clearly demonstrates the potential of such a methodology. In addition to the taxa previously detected via macrofossil and palynological analyses, aDNA analysis identified unreported plant and animal taxa, some of which are locally extinct or endemic. The survival and preservation of DNA in hot, arid environments is a complex and poorly understood process that is both sporadic and rare, but the survival of DNA through desiccation may be important. Herbivore middens now present an important source of material for DNA metabarcoding studies of hot, arid palaeoenvironments and can potentially be used to analyse middens in these environments throughout Australia, Africa, the Americas and the Middle East.
- Published
- 2012
194. Potential pitfalls: financial planning challenges for registered domestic partners
- Author
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Chase, Brian
- Subjects
Financial planning -- Laws, regulations and rules ,Unmarried couples -- Finance -- Laws, regulations and rules ,Government regulation ,Company financing ,Banking, finance and accounting industries ,Business ,California. Domestic Partner Rights and Responsibilities Act - Abstract
California's Domestic Partner Rights and Responsibilities Act (AB 205) went into effect Jan. 1, 2005. Though a number of clean-up provisions went into effect Jan. 1, 2006 that provide clarity [...]
- Published
- 2006
195. Vegetation changes during the past 40,000 years in Central China from a long fossil record
- Author
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Li, Jie, primary, Zheng, Zhuo, additional, Huang, Kangyou, additional, Yang, Shixiong, additional, Chase, Brian, additional, Valsecchi, Verushka, additional, Carré, Matthieu, additional, and Cheddadi, Rachid, additional
- Published
- 2013
- Full Text
- View/download PDF
196. A high resolution 15,600-year pollen and microcharcoal record from the Cederberg Mountains, South Africa
- Author
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Valsecchi, Verushka, primary, Chase, Brian M., additional, Slingsby, Jasper A., additional, Carr, Andrew S., additional, Quick, Lynne J., additional, Meadows, Michael E., additional, Cheddadi, Rachid, additional, and Reimer, Paula J., additional
- Published
- 2013
- Full Text
- View/download PDF
197. Quantification of climate change for the last 20,000years from Wonderkrater, South Africa: Implications for the long-term dynamics of the Intertropical Convergence Zone
- Author
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Truc, Loïc, primary, Chevalier, Manuel, additional, Favier, Charly, additional, Cheddadi, Rachid, additional, Meadows, Michael E., additional, Scott, Louis, additional, Carr, Andrew S., additional, Smith, Gideon F., additional, and Chase, Brian M., additional
- Published
- 2013
- Full Text
- View/download PDF
198. Biome-scale characterisation and differentiation of semi-arid and arid zone soil organic matter compositions using pyrolysis–GC/MS analysis
- Author
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Carr, Andrew S., primary, Boom, Arnoud, additional, Chase, Brian M., additional, Meadows, Michael E., additional, Roberts, Zoë E., additional, Britton, Matthew N., additional, and Cumming, Alex M.J., additional
- Published
- 2013
- Full Text
- View/download PDF
199. Temperature variability over Africa during the last 2000 years
- Author
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Nicholson, Sharon E, primary, Nash, David J, additional, Chase, Brian M, additional, Grab, Stefan W, additional, Shanahan, Timothy M, additional, Verschuren, Dirk, additional, Asrat, Asfawossen, additional, Lézine, Anne-Marie, additional, and Umer, Mohammed, additional
- Published
- 2013
- Full Text
- View/download PDF
200. Mapping Protein Structure Changes with Cysteine Labeling Kinetics Measured by Mass Spectrometry
- Author
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Chase, Brian C., primary, Swift, Joe, additional, Pajerowski, J. David, additional, Tang, Hsin-Yao, additional, Speicher, David, additional, and Discher, Dennis, additional
- Published
- 2013
- Full Text
- View/download PDF
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