Showing 11 - 20 of 5709 Items

Date: 2021-01-01
Creator: Cecilia Markmann
Access: Access restricted to the Bowdoin Community
Date: 1971-01-01
Access: Open access
- Bowdoin College Bulletin no. 378
Date: 2011-01-01
Creator: David J. Lewis, Andrew J. Plantinga, Erik Nelson, Stephen Polasky
Access: Open access
- Habitat loss is a primary cause of loss of biodiversity but conserving habitat for species presents challenges. Land parcels differ in their ability to produce returns for landowners and landowners may have private information about the value of the land to them. Land parcels also differ in the type and quality of habitat and the spatial pattern of land use across multiple landowners is important for determining the conservation value of parcels. This paper analyzes the relative efficiency of simple voluntary incentive-based policies in achieving biodiversity conservation objectives. This topic is important not just for biodiversity conservation but for any effort to provide a public good requiring coordination across multiple decision-makers who have some degree of private information. We develop a method that integrates spatially explicit data, an econometric model of private land-use decisions, landscape simulations, a biological model of biodiversity as a function of landscape pattern, and an algorithm that estimates the set of efficient solutions. These methods allow us to simulate landowner responses to policies, measure the consequences of these decisions for biodiversity conservation, and compare these outcomes to efficient outcomes to show the relative efficiency of various policy approaches. We find substantial differences in biodiversity conservation scores generated by simple voluntary incentive-based policies and efficient solutions. The performance of incentive-based policies is particularly poor at low levels of the conservation budget where spatial fragmentation of conserved parcels is a large concern. Performance can be improved by encouraging agglomeration of conserved habitat and by incorporating basic biological information, such as that on rare habitats, into the selection criteria. © 2010 Elsevier B.V.

Date: 2019-05-01
Creator: Gina Fickera
Access: Access restricted to the Bowdoin Community
Date: 2018-01-01
Creator: P. Jeremy Werdell, Lachlan I.W. McKinna, Emmanuel Boss, Steven G. Ackleson, Susanne E., Craig, Watson W. Gregg, Zhongping Lee, Stéphane Maritorena, Collin S. Roesler, Cécile S. Rousseaux, Dariusz Stramski, James M. Sullivan, Michael S. Twardowski, Maria Tzortziou, Xiaodong Zhang
Access: Open access
- Ocean color measured from satellites provides daily global, synoptic views of spectral water-leaving reflectances that can be used to generate estimates of marine inherent optical properties (IOPs). These reflectances, namely the ratio of spectral upwelled radiances to spectral downwelled irradiances, describe the light exiting a water mass that defines its color. IOPs are the spectral absorption and scattering characteristics of ocean water and its dissolved and particulate constituents. Because of their dependence on the concentration and composition of marine constituents, IOPs can be used to describe the contents of the upper ocean mixed layer. This information is critical to further our scientific understanding of biogeochemical oceanic processes, such as organic carbon production and export, phytoplankton dynamics, and responses to climatic disturbances. Given their importance, the international ocean color community has invested significant effort in improving the quality of satellite-derived IOP products, both regionally and globally. Recognizing the current influx of data products into the community and the need to improve current algorithms in anticipation of new satellite instruments (e.g., the global, hyperspectral spectroradiometer of the NASA Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) mission), we present a synopsis of the current state of the art in the retrieval of these core optical properties. Contemporary approaches for obtaining IOPs from satellite ocean color are reviewed and, for clarity, separated based their inversion methodology or the type of IOPs sought. Summaries of known uncertainties associated with each approach are provided, as well as common performance metrics used to evaluate them. We discuss current knowledge gaps and make recommendations for future investment for upcoming missions whose instrument characteristics diverge sufficiently from heritage and existing sensors to warrant reassessing current approaches.
Date: 2008-12-01
Creator: Laura A. Henry, Vladimir Douhovnikoff
Access: Open access
- This review examines the literature available on the state of the environment and environmental protection in the Russian Federation. As the largest country on Earth, rich in natural resources and biodiversity, Russia's problems and policies have global consequences. Environmental quality and management are influenced by the legacy of Soviet economic planning and authoritarian governance, as well as by Russia's post-Soviet economic recession and current strategies of economic development. Russia achieved a reduction in some pollutants owing to the collapse of industrial production in the 1990s, but many environmental indicators suggest growing degradation. Russia has signed on to a number of international environmental agreements, but its record on implementation is mixed, and it discourages environmental activism. Scholarship on the Russian environment is a limited, but growing, field, constrained by challenges of data availability, yet it offers great potential for testing scientific and social scientific hypotheses. ©2008 by Annual Reviews.
Date: 2016-11-01
Creator: Robert W. Brown, Stephen G. Naculich
Access: Open access
- Tree-level n-point gauge-theory amplitudes with n − 2k gluons and k pairs of (massless or massive) particles in the fundamental (or other) representation of the gauge group are invariant under a set of symmetries that act as momentum-dependent shifts on the color factors in the cubic decomposition of the amplitude. These symmetries lead to gauge-invariant constraints on the kinematic numerators. They also directly imply the BCJ relations among the Melia-basis primitive amplitudes previously obtained by Johansson and Ochirov.
Date: 1937-01-01
Access: Open access
- Bowdoin College Bulletin no. 234
Date: 1994-01-01
Creator: Y. Kubota, M. Lattery, J. K. Nelson, S. Patton, D., Perticone, R. Poling, V. Savinov, S. Schrenk, R. Wang, M. S. Alam, I. J. Kim, B. Nemati, J. J. O'Neill, H. Severini, C. R. Sun, M. M. Zoeller, G. Crawford, C. M. Daubenmier, R. Fulton, D. Fujino, K. K. Gan, K. Honscheid, H. Kagan, R. Kass, J. Lee, R. Malchow, F. Morrow, Y. Skovpen, M. Sung, C. White, F. Butler
Access: Open access
- Using the CLEO II detector, we have obtained evidence for a new meson decaying to D0K+. Its mass is 2573.2-1.6+1.7±0.8±0.5 MeV/c2 and its width is 16-4+5±3 MeV/c2. Although we do not establish its spin and parity, the new meson is consistent with predictions for an L=1, S=1, JP=2+ charmed strange state. © 1994 The American Physical Society.