Showing 5501 - 5550 of 5840 Items
Date: 2014-01-01
Creator: Nalini M Nadkarni, Nathaniel T Wheelwright
Access: Open access
- The Monteverde Cloud Forest Reserve has captured the worldwide attention of biologists, conservationists, and ecologists and has been the setting for extensive investigation over the past 40 years. Roughly 40,000 ecotourists visit the Cloud Forest each year, and it is often considered the archetypal high-altitude rain forest. “Monteverde: Ecology and Conservation of a Tropical Cloud Forest”, edited by Nalini Nadkarni and Nathaniel T. Wheelwright (Oxford University Press, 2000 and Bowdoin’s Scholar’s Bookshelf. Book 1 ), features synthetic chapters and specific accounts written by more than 100 biologist and local residents, presenting in a single volume everything known in 2000 about the biological diversity of Monteverde, Costa Rica, and how to protect it. The new short chapters written in 2014 by original contributors, and presented here update and expand that knowledge through 2014.
Date: 2023-12-01
Creator: Eli Franklin
- This paper was submitted as part of EDUC 2285 Ivory Tower: Higher Education in American History, Fall 2023.
Date: 2023-12-01
Creator: Zach Carlson
- This paper was submitted as part of EDUC 2285 Ivory Tower: Higher Education in American History, Fall 2023.
Date: 2023-12-01
Creator: Paulina Morales
- This paper was submitted as part of EDUC 2285 Ivory Tower: Higher Education in American History, Fall 2023.
Date: 2023-12-01
Creator: Jiahn Son
- This paper was submitted as part of EDUC 2285 Ivory Tower: Higher Education in American History, Fall 2023.
Date: 2012-11-08
Creator: Kenneth A. Dennison, Thomas W. Baumgarte
Access: Open access
- Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In analogy to electric and magnetic fields, these fields are coordinate-dependent. However, in a further analogy, we can form invariants from the tendex and vortex fields that are invariant under coordinate transformations, just as certain combinations of the electric and magnetic fields are invariant under coordinate transformations. We derive these invariants, and provide a simple, analytical demonstration for nonspherically symmetric slices of a Schwarzschild spacetime. © 2012 American Physical Society.
Date: 2011-08-11
Creator: Murat Aydin, Kristal R. Verhulst, Eric S. Saltzman, Mark O. Battle, Stephen A., Montzka, Donald R. Blake, Qi Tang, Michael J. Prather
Access: Open access
- Methane and ethane are the most abundant hydrocarbons in the atmosphere and they affect both atmospheric chemistry and climate. Both gases are emitted from fossil fuels and biomass burning, whereas methane (CH 4) alone has large sources from wetlands, agriculture, landfills and waste water. Here we use measurements in firn (perennial snowpack) air from Greenland and Antarctica to reconstruct the atmospheric variability of ethane (C 2H 6) during the twentieth century. Ethane levels rose from early in the century until the 1980s, when the trend reversed, with a period of decline over the next 20 years. We find that this variability was primarily driven by changes in ethane emissions from fossil fuels; these emissions peaked in the 1960s and 1970s at 14-16 teragrams per year (1 Tg = 10 12 g) and dropped to 8-10 Tg yr -1 by the turn of the century. The reduction in fossil-fuel sources is probably related to changes in light hydrocarbon emissions associated with petroleum production and use. The ethane-based fossil-fuel emission history is strikingly different from bottom-up estimates of methane emissions from fossil-fuel use, and implies that the fossil-fuel source of methane started to decline in the 1980s and probably caused the late twentieth century slow-down in the growth rate of atmospheric methane. © 2011 Macmillan Publishers Limited. All rights reserved.
Date: 1991-01-01
Creator: D. S. Akerib, B. Barish, D. F. Cowen, G. Eigen, R., Stroynowski, J. Urheim, A. J. Weinstein, R. Morrison, D. Schmidt, M. Procario, D. R. Johnson, K. Lingel, P. Rankin, J. G. Smith, J. Alexander, C. Bebek, K. Berkelman, D. Besson, T. E. Browder, D. G. Cassel, E. Cheu, D. M. Coffman, P. S. Drell, R. Ehrlich, R. S. Galik, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley
Access: Open access
- Using the CLEO II detector at the Cornell Electron Storage Ring, we have determined the inclusive B* cross section above the (4S) resonance in the energy range from 10.61 to 10.70 GeV. We also report a new measurement of the energy of the B*B transition photon of 46.20.30.8 MeV. © 1991 The American Physical Society.
Date: 2003-01-01
Creator: T.W. Baumgarte, S.L. Shapiro
Access: Open access
Date: 2015-01-01
Creator: N. Sanchis-Gual, P.J. Montero, J.A. Font, E. Müller, T.W., Baumgarte
Access: Open access
Date: 1993-01-01
Creator: R. Balest, M. Daoudi, W. T. Ford, D. R. Johnson, K., Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, D. Besson, T. E. Browder, D. G. Cassel, H. A. Cho, D. M. Coffman, P. S. Drell, R. Ehrlich, R. S. Galik, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, K. Honscheid, C. D. Jones, J. Kandaswamy, N. Katayama, P. C. Kim, D. L. Kreinick
Access: Open access
- Using data from the CLEO II detector at CESR, we measure the τ-lepton mass by exploiting the unique kinematics of events in which both τ's decay hadronically. The result is mτ=1777.8±0.7±1.7 MeV/c2. By comparing our result with other measurements near τ-pair threshold, we extract an upper limit on the τ-neutrino mass of 75 MeV/c2 at 95% confidence level. © 1993 The American Physical Society.
Date: 1992-01-01
Creator: G. Crawford, R. Fulton, T. Jensen, D. R. Johnson, H., Kagan, R. Kass, R. Malchow, F. Morrow, J. Whitmore, P. Wilson, D. Bortoletto, D. Brown, J. Dominick, R. L. McIlwain, D. H. Miller, M. Modesitt, C. R. Ng, S. F. Schaffner, E. I. Shibata, I. P.J. Shipsey, M. Battle, H. Kroha, K. Sparks, E. H. Thorndike, C. H. Wang, M. S. Alam, I. J. Kim, W. C. Li, X. C. Lou, B. Nemati, V. Romero
Access: Open access
- Using the CLEO detector at the Cornell Electron Storage Ring, we observe B-meson decays to c+ and report on improved measurements of inclusive branching fractions and momentum spectra of other baryons. For the inclusive decay Bc+X with c+pK-+, we find that the product branching fraction B(Bc+X)B(c+pK-+)=(0.273±0.051±0.039)%. Our measured inclusive branching fractions to noncharmed baryons are B(BpX)=(8.0±0.5±0.3)%, B(BX)=(3.8±0.4±0.6)%, and B(B-X)=(0.27±0.05±0.04)%. From these rates and studies of baryon-lepton and baryon-antibaryon correlations in B decays, we have estimated the branching fraction B(Bc+X) to be (6.40.8±0.8)%. Combining these results, we calculate B(c+pK-) to be (4.3±1.0±0.8)%. © 1992 The American Physical Society.
Date: 2011-12-01
Creator: Stephen G. Naculich, Horatiu Nastase, Howard J. Schnitzer
Access: Open access
- A number of features and applications of subleading-color amplitudes of N = 4 SYM theory are reviewed. Particular attention is given to the IR divergences of the subleading-color amplitudes, the relationships of N = 4 SYM theory to N = 8 supergravity, and to geometric interpretations of one-loop subleading-color and N k MHV amplitudes of N = 4 SYM theory. Copyright © 2011 Stephen G. Naculich et al.
Date: 2013-08-16
Creator: M. Rubino, D. M. Etheridge, C. M. Trudinger, C. E. Allison, M. O., Battle, R. L. Langenfelds, L. P. Steele, M. Curran, M. Bender, J. W.C. White, T. M. Jenk, T. Blunier, R. J. Francey
Access: Open access
- We present new measurements of δ13C of CO2 extracted from a high-resolution ice core from Law Dome (East Antarctica), together with firn measurements performed at Law Dome and South Pole, covering the last 150 years. Our analysis is motivated by the need to better understand the role and feedback of the carbon (C) cycle in climate change, by advances in measurement methods, and by apparent anomalies when comparing ice core and firn air δ13C records from Law Dome and South Pole. We demonstrate improved consistency between Law Dome ice, South Pole firn, and the Cape Grim (Tasmania) atmospheric δ13C data, providing evidence that our new record reliably extends direct atmospheric measurements back in time. We also show a revised version of early δ13C measurements covering the last 1000 years, with a mean preindustrial level of -6.50‰. Finally, we use a Kalman Filter Double Deconvolution to infer net natural CO2 fluxes between atmosphere, ocean, and land, which cause small δ13C deviations from the predominant anthropogenically induced δ13C decrease. The main features found from the previous δ13C record are confirmed, including the ocean as the dominant cause for the 1940 A.D. CO2 leveling. Our new record provides a solid basis for future investigation of the causes of decadal to centennial variations of the preindustrial atmospheric CO2 concentration. Those causes are of potential significance for predicting future CO2 levels and when attempting atmospheric verification of recent and future global carbon emission mitigation measures through Coupled Climate Carbon Cycle Models. Key Points New and revised, firn and ice δ13C-CO2 measurements from Antarctica Improve consistency between ice and firn δ13C-CO2 measurements Net natural CO2 fluxes between atmosphere, ocean and land inferred ©2013. American Geophysical Union. All Rights Reserved.
Date: 1996-01-01
Creator: Michael Crescimanno, Stephen G. Naculich, Howard J. Schnitzer
Access: Open access
- The free energy in the weak-coupling phase of two-dimensional Yang-Mills theory on a sphere for [Formula presented] and [Formula presented] is evaluated in the [Formula presented] expansion using the techniques of Gross and Matytsin. Many features of Yang-Mills theory are universal among different gauge groups in the large [Formula presented] limit, but significant differences arise in subleading order in [Formula presented]. © 1996 The American Physical Society.
Date: 2009-11-11
Creator: Stephen G. Naculich, Howard J. Schnitzer
Access: Open access
- We derive a compact all-loop-order expression for the IR-divergent part of the = 4 SYM four-gluon amplitude, which includes both planar and all subleading-color contributions, based on the assumption that the higher-loop soft anomalous dimension matrices are proportional to the one-loop soft anomalous dimension matrix, as has been recently conjectured. We also consider the Regge limit of the four-gluon amplitude, and we present evidence that the leading logarithmic growth of the subleading-color amplitudes is less severe than that of the planar amplitudes. We examine possible 1/N 2 corrections to the gluon Regge trajectory, previously obtained in the planar limit from the BDS ansatz. The double-trace amplitudes have Regge behavior as well, with a nonsense-choosing Regge trajectory and a Regge cut which first emerges at three loops. © SISSA 2009.