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693.
Understanding of the gathering of nontimber forest products (NTFPs) in woodlands has focused heavily on politics surrounding public lands and harvester communities. Yet forest gathering may be far more universal. This paper reports the results of a survey of residents in New England, querying whether people gather wild things and for what purposes. The results suggest that gathering in New England, and elsewhere in the developed world, is not restricted to a unique type of community or economy, but instead is a form of practice. Those analytical approaches to NTFPs that seek to produce 'alternatives' to the dominant economy may therefore ironically work to reinforce a capitalocentric view of daily life. 相似文献
694.
Controls of Wellbore Flow Regimes on Pump Effluent Composition 总被引:1,自引:0,他引:1
Where well water and formation water are compositionally different or heterogeneous, pump effluent composition will vary due to partial mixing and transport induced by pumping. Investigating influences of purging and sampling methodology on composition variability requires quantification of wellbore flow regimes and mixing. As a basis for this quantification, analytical models simulating Poiseuille flow were developed to calculate flow paths and travel times. Finite element modeling was used to incorporate influences of mixing. Parabolic velocity distributions within the screened interval accelerate with cumulative inflow approaching the pump intake while an annulus of inflowing formation water contracts uniformly to displace an axial cylinder of pre‐pumping well water as pumping proceeds. Increased dispersive mixing forms a more diffuse formation water annulus and the contribution of formation water to pump effluent increases more rapidly. Models incorporating viscous flow and diffusion scale mixing show that initially pump effluent is predominantly pre‐pumping well water and compositions vary most rapidly. After two screen volumes of pumping, 94% of pump effluent is inflowing formation water. Where the composition of formation water and pre‐pumping well water are likely to be similar, pump effluent compositions will not vary significantly and may be collected during early purging or with passive sampling. However, where these compositions are expected to be considerably different or heterogeneous, compositions would be most variable during early pumping, that is, when samples are collected during low‐flow sampling. Purging of two screen volumes would be required to stabilize the content and collect a sample consisting of 94% formation water. 相似文献
695.
696.
While women own 25% of the acres rented out for farming, little has been done in terms of federal policy that focuses on these women. In this policy analysis, we detail how (1) lack of data on these women landowners and (2) the invisibility of these women to federal natural resource and agricultural agency staff contribute to women nonoperating landowners (WNOLs) not being on the federal policy radar. We discuss how the persistence of these factors continues to marginalize WNOLs in federal agricultural policy, despite the mandate of U.S. Department of Agriculture (USDA) agencies to be serving underserved populations such as WNOLs. Our study findings clearly illustrate a critical point: federal agricultural/conservation agencies are not fulfilling their mandate to reach WNOLs. Using data from USDA Production Regions in the United States, we detail how WNOLs are marginalized and provide specific policy recommendations to allow for intentional inclusion of these women. 相似文献
697.
Jack?WisdomEmail authorView authors OrcID profile Jennifer?Meyer 《Celestial Mechanics and Dynamical Astronomy》2016,126(1-3):1-30
This is an exploration of dynamic tides on elastic bodies. The body is thought of as a dynamical system described by its modes of oscillation. The dynamics of these modes are governed by differential equations that depend on the rheology. The modes are damped by dissipation. Tidal friction occurs as exterior bodies excite the modes and the modes act back on the tide raising body. The whole process is governed by a closed set of differential equations. Standard results from tidal theory are recovered in a two-timescale approximation to the solution of these differential equations. 相似文献
698.
Alfred S. McEwen Maria E. Banks Kris Becker James W. Bergstrom Edward Bortolini Shane Byrne Frank C. Chuang Ingrid Daubar Donald G. Deardorff W. Alan Delamere Colin M. Dundas Yisrael Espinoza Kathryn E. Fishbaugh Paul E. Geissler Jennifer L. Griffes Virginia C. Gulick Kenneth E. Herkenhoff Windy L. Jaeger Bob Kanefsky Robert King Kelly J. Kolb Alexandra Lefort Kevin W. Lewis Sarah Mattson Michael T. Mellon Moses P. Milazzo Tahirih Motazedian Albert Ortiz Joseph Plassmann Patrick S. Russell Mindi L. Searls Steven W. Squyres Nicolas Thomas Livio L. Tornabene Circe Verba James J. Wray 《Icarus》2010,205(1):2-216
The High Resolution Imaging Science Experiment (HiRISE) on the Mars Reconnaissance Orbiter (MRO) acquired 8 terapixels of data in 9137 images of Mars between October 2006 and December 2008, covering ∼0.55% of the surface. Images are typically 5-6 km wide with 3-color coverage over the central 20% of the swath, and their scales usually range from 25 to 60 cm/pixel. Nine hundred and sixty stereo pairs were acquired and more than 50 digital terrain models (DTMs) completed; these data have led to some of the most significant science results. New methods to measure and correct distortions due to pointing jitter facilitate topographic and change-detection studies at sub-meter scales. Recent results address Noachian bedrock stratigraphy, fluvially deposited fans in craters and in or near Valles Marineris, groundwater flow in fractures and porous media, quasi-periodic layering in polar and non-polar deposits, tectonic history of west Candor Chasma, geometry of clay-rich deposits near and within Mawrth Vallis, dynamics of flood lavas in the Cerberus Palus region, evidence for pyroclastic deposits, columnar jointing in lava flows, recent collapse pits, evidence for water in well-preserved impact craters, newly discovered large rayed craters, and glacial and periglacial processes. Of particular interest are ongoing processes such as those driven by the wind, impact cratering, avalanches of dust and/or frost, relatively bright deposits on steep gullied slopes, and the dynamic seasonal processes over polar regions. HiRISE has acquired hundreds of large images of past, present and potential future landing sites and has contributed to scientific and engineering studies of those sites. Warming the focal-plane electronics prior to imaging has mitigated an instrument anomaly that produces bad data under cold operating conditions. 相似文献
699.
Siobahn M. Morgan Jennifer N. Wahl Rachel M. Wieckhorst 《Monthly notices of the Royal Astronomical Society》2007,374(4):1421-1426
[Fe/H]–φ31 – P relations are found for c-type RR Lyrae stars in globular clusters. The relations are analogous to that found by Jurcsik & Kovács for field ab-type RR Lyrae stars, where a longer period correlates with lower metallicity values for similar values of the Fourier coefficient φ31 . The relations obtained here are used to determine the metallicity of field c-type RR Lyrae stars, those within ω Cen, the Large Magellanic Cloud and toward the galactic bulge. The results are found to compare favourably to metallicity values obtained elsewhere. 相似文献
700.
Andrew S. Rivkin Cristina A. Thomas David E. Trilling Marie-therese Enga Jennifer A. Grier 《Icarus》2011,211(2):1294-1297
A survey of small (<5-10 km diameter) members of the Koronis family shows some objects with visible-wavelength broadband colors consistent with membership in the Q-class (Tholen, D.J. [1984]. Asteroid taxonomy from cluster analysis of photometry. Ph.D. Dissertation, University of Arizona, Tucson, AZ; Bus, S.J., Binzel, R.P. [2002]. Icarus 158, 146-177). This agrees with an ordinary chondritic composition for this family and suggests the timescale for changing Q-class to S-class spectra in the main belt is roughly comparable to the regolith refresh time in the 2-5 km size range. 相似文献