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71.
Stocking of largemouth bass is an important management tool for fish management. The stocking of hatchery‐produced fingerling or advanced‐fingerling bass to supplement bass year‐classes, however, has exhibited varying success. Utilizing a different approach, a multiyear stocking programme using wild adult largemouth bass was initiated at the Harris Chain of Lakes (3800 ha Lake Griffin; 1811 ha Lake Dora) in central Florida. Wild adult bass (24 781 fish), ranging in size from 200 mm total length (TL) to over 600 mm TL, were stocked in Lake Griffin (13 932 fish) and Lake Dora (10 849 fish). One month after stocking, the number of stocked bass caught in electrofishing catches in Lake Griffin and Lake Dora was ~10% and 22%, respectively. Estimates of mortality were similar to the native largemouth bass, although the movement of stocked fish into other connecting water bodies was extensive. For the Lake Griffin/Lake Dora stocking programme, bass were transferred at a cost of $10.09–19.89 per fish, depending on how the costs of the project are calculated ($250 000 for just the capture and transport of the fish vs. $492 775 for the total project). Considering only capture and transport costs, conservative benefit/cost ratio estimates would be $1.77/$1.00 spent for replacement and $1.85/$1.00 spent recreational costs, although the benefit/cost ratios could exceed $10/$1. Based on the present study, stocking wild adult largemouth bass is a cost‐effective tool for managing largemouth bass.  相似文献   
72.
A 0.745 L 2-cylinder spark-ignition engine was operated with compressed natural gas and with simulated landfill gas (60% CH4 and 40% CO2 by volume) containing hydrogen concentrations of 0, 30%, 40%, and 50% (by volume of the CH4 in the fuel) at constant rpm. This empirical data was compared with predictions from three existing semi-empirical engine models, using a first-law-based finite heat release model to correlate measured in-cylinder pressure data and burn rate for each fuel mixture. Of the three models only a two zone model incorporating thermal and prompt NOx came within 25% of predicting the measured NOx emissions.  相似文献   
73.
Towards cognitive evaluation of computer-drawn sketches   总被引:1,自引:0,他引:1  
This paper seeks to raise visual comparisons beyond subjective opinions into evidence-based visual reasoning. It provides an informal deductive analysis of the marks in sketches derived with two competing line-filtering algorithms. This prompted the novel speculation that the visual system might be placing some types of anomalies in the foreground of mental 3D space, where they can be ignored. A brief survey is provided to encourage informed debate. Although the proposed cognitive computation was not automated, it justified the rejection of the Douglas–Peucker algorithm in favour of Visvalingam's algorithm in subsequent research within the Cartographic Information Systems Research Group (CISRG).  相似文献   
74.
By extending the formalism previously developed for the design of unshielded, biplanar gradient coils, shielded biplanarB 0 coils optimized for homogeneity and either minimum energy or minimum power may be designed. We present results from an integrated approach to shielded biplanar coil design, the results of which are also applicable to gradient coils, enabling the design of shielded coils with a concomitant decrease in total inductance of the coil. Length constraints are also included in the integrated minimization procedure. Results from a preliminary design indicate that high-homogeneity, low-impedance, well-shielded coils result from this design approach.  相似文献   
75.

Sciencenews10-Jahr-Feier

Institut für Maschinelles Sehen und Darstellen  相似文献   
76.
The method of Fourier optics is applied to the problem of time-gated imaging through scattering media. Tb adapt the problem to this treatment, appropriate alterations are made: The continuous medium is replaced by a cascade of thin scatterers, and a spatial filtering process is substituted for the conventional gating processes. Closed-form solutions are derived.  相似文献   
77.
We have performed high-dose Fe ion implantation into Si and characterized ion-beam-induced microstructures as well as annealing-induced ones using transmission electron microscopy (TEM) and grazing-incidence X-ray diffraction (GIXRD). Single crystals of Si(1 0 0) substrate were irradiated at 623 K with 120 keV Fe+ ions to a fluence of 4 × 1017 cm−2. The irradiated samples were then annealed in a vacuum furnace at temperatures ranging from 773 K to 1073 K. Cross-sectional TEM observations and GIXRD measurements revealed that a layered structure is formed in the as-implanted specimen with ε-FeSi, β-FeSi2 and damaged Si, as component layers. A continuous β-FeSi2 layer was formed on the topmost layer of the Si substrate after thermal annealing.  相似文献   
78.
Kurt Beyer 《AI & Society》2002,16(3):278-287
This narrative describes the making of a German electrical engineer, Kurt Beyer, into a micro-entrepreneur. He set for himself the goal of sailing around the world in his own vessel – without being able to afford to buy such a ship. Many people in Germany have in recent years started to build their own sea-going vessels in order to escape from the creativity-stifling and restrictive patterns of their lives and work. Only a few of them have ever finished building their vessels. Firstly, this report describes the experiences of one of those few who have made it. Secondly, it tells the story of how this engineer himself turned into a micro-entrepreneur during the period of yacht-building and how later he started his own charter enterprise, centred around his yacht. Following the model of entrepreneurship described by Dassen-Housen in this issue of AI & Society, the narrative illustrates what it means to run such an enterprise in view of the international competition. Here follows the narrative of the engineer and ship-builder himself (translated by D. Brandt).  相似文献   
79.
The objective of this study is to investigate experimentally and theoretically whether sodium carbonate (Na2CO3) salt is suitable for establishing a salinity gradient in a salt-gradient solar-pond (SGSP). For this purpose, a small-scale prismatic solar-pond was constructed. Experiments were conducted in the laboratory under the incident radiation from two halogen-lamps acting as a solar simulator. Furthermore, a one-dimensional transient mathematical model that describes the heat and mass transfer behaviour of the SGSP was developed. The differential equations obtained were solved numerically using a finite-difference method. It was found from the experiments that the density gradient, achieved using sodium carbonate salt, can suppress convection from the bottom to the surface of the pond.  相似文献   
80.
Assessed 100 undergraduates' developmental theories about their affective relationships with their parents, using a retrospective method. Ss used drawings and questionnaire ratings to portray their relationships with parents at 5 points between infancy and the present. From infancy to their current age, Ss portrayed their relationships in 2 major ways: They perceived themselves as gaining in responsibility, dominance, independence, and similarity from infancy to the present, whereas they portrayed their parents as experiencing a decline on these dimensions. For variables indicating closeness and love, however, there was a striking discontinuity in these linear trends: Although Ss perceived linear trends from infancy to adolescence, they depicted their current relationships as involving a great deal more love and closeness. They also portrayed their relationships with mothers and fathers somewhat differently. More responsibility was felt toward the mothers and they were portrayed as especially friendly, but Ss felt more similar to their fathers, whom they perceived as dominant. Results suggest that late adolescents construct theories of the affective components of their relationships with their parents to serve the needs of separation while maintaining a close affective tie to the parents. (24 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
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