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1.
Design improvements on swim fins are most difficult, if not impossible, to assess quantitatively by swimmers alone. In order to make reliable measurements of swim fin performance, an instrumented mechanical swimming device was developed and operated in a water tank. Using this facility, the performance of the more popular conventional fins and that of a new design concept were evaluated. The comparative performance of the various fins was correlated with their physical characteristics. 相似文献
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Clare E. Reimers H. Tuba Özkan-Haller Rhea D. Sanders Kristina McCann-Grosvenor Peter J. Chace Sean A. Crowe 《Aquatic Geochemistry》2016,22(5-6):505-527
Mid-shelf sediments off the Oregon coast are characterized as fine sands that trap and remineralize phytodetritus leading to the consumption of significant quantities of dissolved oxygen. Sediment oxygen consumption (SOC) can be delayed from seasonal organic matter inputs because of a transient buildup of reduced constituents during periods of quiescent physical processes. Between 2009 and 2013, benthic oxygen exchange rates were measured using the noninvasive eddy covariance (EC) method five separate times at a single 80-m station. Ancillary measurements included in situ microprofiles of oxygen at the sediment–water interface, and concentration profiles of pore water nutrients and trace metals, and solid-phase organic C and sulfide minerals from cores. Sediment cores were also incubated to derive anaerobic respiration rates. The EC measurements were made during spring, summer, and fall conditions, and they produced average benthic oxygen flux estimates that varied between ?2 and ?15 mmol m?2 d?1. The EC oxygen fluxes were most highly correlated with bottom-sensed, significant wave heights (H s). The relationship with H s was used with an annual record of deepwater swell heights to predict an integrated oxygen consumption rate for the mid-shelf of 1.5 mol m?2 for the upwelling season (May–September) and 6.8 mol m?2 y?1. The annual prediction requires that SOC rates are enhanced in the winter because of sand filtering and pore water advection under large waves, and it counters budgets that assume a dominance of organic matter export from the shelf. Refined budgets will require winter flux measurements and observations from cross-shelf transects over multiple years. 相似文献
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A. Baran R. Oreiro A. Pigulski F. Pérez Hernández A. Ulla M. D. Reed C. Rodríguez-López P. Moskalik S.-L. Kim W.-P. Chen R. Crowe M. Siwak L. Armendarez P. M. Binder K.-J. Choo A. Dye J. R. Eggen R. Garrido J. M. González Pérez S. L. Harms F.-Y. Huang D. Kozie&#; H.-T. Lee J. MacDonald L. Fox Machado T. Monserrat J. Stevick S. Stewart D. Terry A.-Y. Zhou S. Zo&#;a 《Monthly notices of the Royal Astronomical Society》2009,392(3):1092-1105
4.
Hydrogeologic delineation of habitats for endangered species: the Comal Springs/River System 总被引：1，自引：0，他引：1
We delineate 18 distinct habitats for the endangered fountain darter in the Comal Springs/River system based upon a combination
of vegetative, geologic, and hydrologic criteria. Comal Springs are the largest natural discharge from the Edwards aquifer
of central Texas; they issue along faults which penetrate the confined portion of the aquifer. The springs are the head of
the Comal River which is an important economic and recreational resource to the local community. The spring/river system is
the home of the fountain darter, a federally listed endangered species. Previous studies of this system were on a large scale
and lacked detail necessary for characterization. The fountain darter and other fauna in the Comal Springs/River system are
threatened by the possibility of diminished flows and the concomitant habitat change. The 18 habitats are defined by the dominant
species of vegetation, the substrate, and the flow conditions. Human alterations and spring discharge control the morphology
of the river and the substrates. Stream velocities determined substrate conditions and, thus indirectly, the distribution
of vegetation and habitats. In this system, hydrochemical parameters were uniform as were the soils adjacent to the stream;
these factors were not important to the habitat delineation. The range of stream velocities necessary to maintain the habitats
can be estimated with the Hjulstrom diagram. The darters were associated with a number of these habitats. We surmise that
significant alteration of the system's habitats will occur if discharge conditions change.
Received: 22 January 1996 · Accepted: 4 March 1996 相似文献
5.
This note describes the use of Microsoft Excel macros (programs written in Excel's internal language, Visual Basic for Applications) to create simple onscreen animations of transient ground water data within Excel. Compared to many specialized visualization software packages, the use of Excel macros is much cheaper, much simpler, and can rapidly be learned. The Excel macro can also be used to create individual GIF files for each animation frame. This series of frames can then be used to create an AVI video file using any of a number of graphics packages, such as Corel PhotoPaint. The technique is demonstrated through a macro that animates changes in the elevation of a water table along a transect over several years. 相似文献
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G. Handler R. R. Shobbrook † M. Jerzykiewicz K. Krisciunas T. Tshenye E. Rodríguez V. Costa A.-Y. Zhou R. Medupe W. M. Phorah R. Garrido P. J. Amado M. Paparó D. Zsuffa L. Ramokgali R. Crowe N. Purves R. Avila R. Knight E. Brassfield P. M. Kilmartin P. L. Cottrell 《Monthly notices of the Royal Astronomical Society》2004,347(2):454-462
8.
Tracey L. Crowe 《Climate Policy》2013,13(1):58-79
The potential of Clean Development Mechanism (CDM) projects to deliver pro-poor benefits at the community level is examined. Both regular CDM and premium add-on standard projects are evaluated, including the Gold Standard and Climate, Community and Biodiversity (CCB) Standard, through the use of seven poverty indicators. Some key characteristics associated with providing pro-poor benefits are also identified. Finally, the market potential of a revised or new premium add-on standard explicitly designed to deliver pro-poor benefits is assessed through the use of a survey. The results indicate that regular CDM projects are only moderately successful at delivering pro-poor benefits. Although the few projects registered that utilize the CCB Standard all performed well in delivering pro-poor benefits, those that used the Gold Standard performed only slightly better than regular CDM projects. Characteristics associated with providing pro-poor benefits include the use of add-on standards, a high level of stakeholder participation, and the development of projects by not-for-profit and government/intergovernmental organizations. The survey of carbon market participants indicated both an interest and desire for Certified Emission Reduction (CER) credits with pro-poor benefits attached and shows that the market potential for such a standard to be quite good. Policy relevance This analysis of the CDM goes beyond sustainable development to consider the potential of a project to deliver pro-poor benefits at the local community level. Specific characteristics associated with projects are identified that appear to deliver pro-poor benefits that may benefit future project design. Through this analysis and identifying these characteristics, actions may be taken to incorporate those into CDM project requirements or guidelines to advance the mechanism as a means to contribute to poverty alleviation. 相似文献
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Impacts of anthropogenic pollution on marine ecosystems are being addressed by legislation to protect and restore coastal and transitional waters. A range of biological measures have been investigated for their ability to indicate anthropogenic disturbance in subtidal soft-sediment habitats, but little work to date has focussed in intertidal habitats. This study investigated the sensitivity of communities, individual taxa, diversity indices and biotic indices to nutrient and organic enrichment in intertidal soft-sediment habitats. Variation in macrofaunal communities was more strongly associated with anthropogenic stressors than with natural environmental variation. Two multimetric indices, M-AMBI and IQI, were more closely associated with nutrient and organic pollution than the AMBI and ITI indices. Intertidal monitoring based on existing monitoring tools offers a cost effective alternative to subtidal monitoring and has potential to form the basis for an ecosystem level approach. 相似文献