Showing 511 - 520 of 733 Items
"Not for ornament": Patenting activity by nineteenth-century women inventors
Date: 2000-01-01
Creator: B. Zorina Khan
Access: Open access
Discrete breathers in a mass-in-mass chain with Hertzian local resonators
Date: 2017-02-22
Creator: S. P. Wallen, J. Lee, D. Mei, C. Chong, P. G., Kevrekidis, N. Boechler
Access: Open access
- We report on the existence of discrete breathers in a one-dimensional, mass-in-mass chain with linear intersite coupling and nonlinear, precompressed Hertzian local resonators, which is motivated by recent studies of the dynamics of microspheres adhered to elastic substrates. After predicting theoretically the existence of discrete breathers in the continuum and anticontinuum limits of intersite coupling, we use numerical continuation to compute a family of breathers interpolating between the two regimes in a finite chain, where the displacement profiles of the breathers are localized around one lattice site. We then analyze the frequency-amplitude dependence of the breathers by performing numerical continuation on a linear eigenmode (vanishing amplitude) solution of the system near the upper band gap edge. Finally, we use direct numerical integration of the equations of motion to demonstrate the formation and evolution of the identified localized modes in energy-conserving and dissipative scenarios, including within settings that may be relevant to future experimental studies.
Fighting for Every Inch of Land: Greed and Grievance in Petition Mobilization in Zhejiang
Date: 2020-07-01
Creator: Christopher Heurlin
Access: Open access
- Despite a proliferation of studies of the micro-level dynamics of protests and petitions against land takings in China, we know very little about how meso-level factors, such as the local economy, influence petitions to Beijing and provincial governments. Drawing upon the economic approach to civil war, this article examines the roles played by grievances and greed in determining the scale of mobilization at the county level in Zhejiang province. Through archival evidence and interviews in Ningbo and Lishui, as well as an original dataset of petitions, this article suggests that both grievances and greed influence petitioning. Mobilization is especially high in Ningbo, where valuable real estate markets have prompted landless farmers to compete with local governments over control of the rents from land. The article proposes the concept of resource value activation as a cognitive mechanism that has contributed to this process of mobilization.
Inventing Prizes: A Historical Perspective on Innovation Awards and Technology Policy
Date: 2015-01-01
Creator: B. Zorina Khan
Access: Open access
- Prizes for innovations are currently experiencing a renaissance, following their marked decline during the nineteenth century. Debates about such incentive mechanisms tend to employ canonical historical anecdotes to motivate and support the analysis and policy proposals. Daguerre's "patent buyout," the Longitude Prize, inducement prizes for butter substitutes and billiard balls, the activities of the Royal Society of Arts and other "encouragement" institutions-all comprise potentially misleading case studies. The article surveys and summarizes extensive empirical research using samples drawn from Britain, France, and the United States, including "great inventors" and their ordinary counterparts, and prizes at industrial exhibitions. The results suggest that administered systems of rewards to innovators suffered from a number of disadvantages in design and practice, which might be inherent to their nonmarket orientation.
Conservation as if people also mattered: Policy and practice of community-based conservation
Date: 2013-01-01
Creator: Ashish Kothari, Philip Camill, Jessica Brown
Access: Open access
- Community-based conservation is being increasingly recognised as a major global force in the protection and sustainable management of ecosystems and species. Yet documentation of its main achievements and shortcomings, and the key issues it faces, is still at a nascent stage. This paper introduces the concept and experience of two forms of community-based conservation: Collaborative Management of Protected Areas (CMPA), and Indigenous Peoples' and Local Community Conserved Territories and Areas (ICCAs). It explores the emergence of these approaches in the context of global international conservation policy. Reviewing four case studies that were presented at a symposium convened at the Bowdoin College (Maine, USA, in November 2008), and drawing from the discussion during that session, it identifies some key lessons and principles that are likely to be applicable to community-based conservation across the world.
Inclusive decays of B mesons to charmonium
Date: 1995-01-01
Creator: R. Balest, K. Cho, W. T. Ford, D. R. Johnson, K., Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, K. Bloom, T. E. Browder, D. G. Cassel, H. A. Cho, D. M. Coffman, D. S. Crowcroft, P. S. Drell, D. J. Dumas, R. Ehrlich, P. Gaidarev, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, S. Henderson, C. D. Jones, S. L. Jones, J. Kandaswamy
Access: Open access
- We have used the CLEO-II detector at the Cornell Electron Storage Ringe (CESR) to study the inclusive production of charmonium mesons in a sample of 2.15 million BB events. We find inclusive branching fractions of (1.120.040.06)% for BJ/X, (0.340.040.03)% for BX, and (0.400.060.04)% for Bc1X. We also find some evidence for the inclusive production of c2, and set an upper limit for the branching fraction of the inclusive decay BcX of 0.9% at 90% confidence level. Momentum spectra for inclusive J/, and c1 production are presented. These measurements are compared to theoretical calculations. © 1995 The American Physical Society.
Atmospheric abundance and global emissions of perfluorocarbons CF4, C2F6 and C3F8 since 1800 inferred from ice core, firn, air archive and in situ measurements
Date: 2016-09-21
Creator: Cathy M. Trudinger, Paul J. Fraser, David M. Etheridge, William T. Sturges, Martin K., Vollmer, Matt Rigby, Patricia Martinerie, Jens Mühle, David R. Worton, Paul B. Krummel, L. Paul Steele, Benjamin R. Miller, Johannes Laube, Francis S. Mani, Peter J. Rayner, Christina M. Harth, Emmanuel Witrant, Thomas Blunier, Jakob Schwander, Simon O'Doherty, Mark Battle
Access: Open access
- Perfluorocarbons (PFCs) are very potent and long-lived greenhouse gases in the atmosphere, released predominantly during aluminium production and semiconductor manufacture. They have been targeted for emission controls under the United Nations Framework Convention on Climate Change. Here we present the first continuous records of the atmospheric abundance of CF4 (PFC-14), C2F6 (PFC-116) and C3F8 (PFC-218) from 1800 to 2014. The records are derived from high-precision measurements of PFCs in air extracted from polar firn or ice at six sites (DE08, DE08-2, DSSW20K, EDML, NEEM and South Pole) and air archive tanks and atmospheric air sampled from both hemispheres. We take account of the age characteristics of the firn and ice core air samples and demonstrate excellent consistency between the ice core, firn and atmospheric measurements. We present an inversion for global emissions from 1900 to 2014. We also formulate the inversion to directly infer emission factors for PFC emissions due to aluminium production prior to the 1980s. We show that 19th century atmospheric levels, before significant anthropogenic influence, were stable at 34.1 ± 0.3 ppt for CF4 and below detection limits of 0.002 and 0.01 ppt for C2F6 and C3F8, respectively. We find a significant peak in CF4 and C2F6 emissions around 1940, most likely due to the high demand for aluminium during World War II, for example for construction of aircraft, but these emissions were nevertheless much lower than in recent years. The PFC emission factors for aluminium production in the early 20th century were significantly higher than today but have decreased since then due to improvements and better control of the smelting process. Mitigation efforts have led to decreases in emissions from peaks in 1980 (CF4) or early-to-mid-2000s (C2F6 and C3F8) despite the continued increase in global aluminium production; however, these decreases in emissions appear to have recently halted. We see a temporary reduction of around 15 % in CF4 emissions in 2009, presumably associated with the impact of the global financial crisis on aluminium and semiconductor production.
Measurement of the branching fraction for D+K-++
Date: 1994-01-01
Creator: R. Balest, K. Cho, M. Daoudi, W. T. Ford, D. R., Johnson, K. Lingel, M. Lohner, P. Rankin, J. G. Smith, J. P. Alexander, C. Bebek, K. Berkelman, K. Bloom, T. E. Browder, D. G. Cassel, H. A. Cho, D. M. Coffman, P. S. Drell, R. Ehrlich, P. Gaiderev, M. Garcia-Sciveres, B. Geiser, B. Gittelman, S. W. Gray, D. L. Hartill, B. K. Heltsley, C. D. Jones, S. L. Jones, J. Kandaswamy, N. Katayama, P. C. Kim
Access: Open access
- Using the CLEO II detector at the Cornell Electron Storage Ring we have measured the ratio of branching fractions, B(D+K-++)/(D0K-+)=2.350.160.16. Our recent measurement of scrB(D0K-+) then gives scrB(D+K-++)=(9.30.60.8)%. © 1994 The American Physical Society.
Wall-associated kinases are expressed throughout plant development and are required for cell expansion
Date: 2001-01-01
Creator: T. A. Wagner, B. D. Kohorn
Access: Open access
- The mechanism by which events in the angiosperm cell wall are communicated to the cytoplasm is not well characterized. A family of five Arabidopsis wall-associated kinases (WAKs) have the potential to provide a physical and signaling continuum between the cell wall and the cytoplasm. The WAKs have an active cytoplasmic protein kinase domain, span the plasma membrane, and contain an N terminus that binds the cell wall. We show here that WAKs are expressed at organ junctions, in shoot and root apical meristems, in expanding leaves, and in response to wall disturbances. Leaves expressing an antisense WAK gene have reduced WAK protein levels and exhibit a loss of cell expansion. WAKs are covalently bound to pectin in the cell wall, providing evidence that the binding of a structural carbohydrate by a receptor-like kinase may have significance in the control of cell expansion.
One-instanton test of a Seiberg-Witten curve from M-theory: The antisymmetric representation of SU(N)
Date: 1998-11-16
Creator: Stephen G. Naculich, Henric Rhedin, Howard J. Schnitzer
Access: Open access
- One-instanton predictions are obtained from the Seiberg-Witten curve derived from M-theory by Landsteiner and Lopez for the Coulomb branch of N = 2 supersymmetric SU(N) gauge theory with a matter hypermultiplet in the antisymmetric representation. Since this cubic curve describes a Riemann surface that is non-hyperelliptic, a systematic perturbation expansion about a hyperelliptic curve is developed, with a comparable expansion for the Seiberg-Witten differential. Calculation of the period integrals of the SW differential by the method of residues of D'Hoker, Krichever, and Phong enables us to compute the prepotential explicitly to one-instanton order. It is shown that the one-instanton predictions for SU(2), SU(3), and SU(4) agree with previously available results. For SU(N), N ≥ 5, our analysis provides explicit predictions of a curve derived from M-theory at the one-instanton level in field theory. © 1998 Elsevier Science B.V.