13,687 research outputs found
Factors influencing biodiversity within organic and conventional systems of arable farming – methodologies and preliminary results
This report was presented at the UK Organic Research 2002 Conference. This paper describes the approaches and preliminary results of a study that is designed to provide a large amount of data at a range of scales in order to investigate the potential factors influencing biodiversity on arable farmland on comparable organic and conventional farms. In particular, the study examines the role of non-crop habitats within the different farming systems and how the extent and management of non-crop habitats differs between them. A detailed description of the methodologies being employed to establish differences in non-crop habitat, plant, invertebrate and bird diversity is given. The study remains in its early stages as a result of the impact of Foot and Mouth disease on the fieldwork schedule during 2001. The process of setting up the study revealed that the numbers of farmers growing cereals organically are low as a proportion of the organic sector as a whole, despite recent large increases in numbers of farmers converting to organic production. Preliminary results from the first year of fieldwork on plants reveal significant differences between organic and conventional farms in terms of the numbers of weed species on fields and non-significant differences in numbers of species found on non-crop habitats
User's guide for atmospheric carbon monoxide transport model
In the winter months of Fairbanks, Alaska, a highly stable air temperature
inversion creates high levels of carbon monoxide (CO) concentrations. As an aid
to understanding this problem, a CO transport computer model has been created
which provides a useful tool when used in conjunction with other measurement and
analytic studies of traffic, meteorology, emissions control, zoning, and parking
management. The model is completely documented and illustrated with several
examples. Named ACOSP (Atmospheric CO Simulation Program), it predicts expected
CO concentrations within a specific geographic area for a defined set of CO
sources. At the present time, the model is programmed to consider automobile
emissions as the major CO source and may include estimates of stationary sources.
The model is coded for computer solution in the FORTRAN programming language and
uses the finite-element method of numerical solution of the basic convective-diffusion
equations. Although it has a potential for real-time analysis and control,
at the present time the model will be most valuable for investigating and understanding
the physical processes which are responsible for high CO levels and for
testing remedial control measures at high speed and low cost
Short period eclipsing binary candidates identified using SuperWASP
We present light curves and periods of 53 candidates for short period eclipsing binary stars identified by SuperWASP. These include 48 newly identified objects with periods <2 × 10^4 s (~0.23 d), as well as the shortest period binary known with main sequence components (GSC2314–0530 = 1SWASP J022050.85 + 332047.6) and four other previously known W UMa stars (although the previously reported periods for two of these four are shown to be incorrect). The period distribution of main sequence contact binaries shows a sharp cut-off at a lower limit of around 0.22 d, but until now, very few systems were known close to this limit. These new candidates will therefore be important for understanding the evolution of low mass stars and to allow investigation of the cause of the period cut-off
Thruster maintenance system Patent
System for removing and repairing spacecraft control thrusters by use of portable air lock
Interferometer
A high resolution interferometer is described. The interferometer is insensitive to slight misalignment of its elements, avoids channeling in the spectrum, generates a maximum equal path fringe contrast, produces an even two sided interferogram without critical matching of the wedge angles of the beamsplitter and compensator wedges, and is optically phase tunable. The interferometer includes a mirror along the path of each beam component produced by the beamsplitter, for reflecting the beam component from the beamsplitter, for reflecting the beam component from the beamsplitter to a corresponding retroreflector and for reflecting the beam returned by the retroreflector back to the beamsplitter. A wedge located along each beam component path, is large enough to cover the retroreflector, so that each beam component passes through the wedge during movement towards the retroreflector and away therefrom
An investigation of surface albedo variations during the recent sahel drought
Applications Technology Satellite 3 green sensor data were used to measure surface reflectance variations in the Sahara/Sahel during the recent drought period; 1967 to 1974. The magnitude of the seasonal reflectance change is shown to be as much as 80% for years of normal precipitation and less than 50% for drought years. Year to year comparisons during both wet and dry seasons reveal the existence of a surface reflectance cycle coincident with the drought intensity. The relationship between the green reflectance and solar albedo is examined and estimated to be about 0.6 times the reflectance change observed by the green channel
Self-recording portable soil penetrometer
A lightweight portable penetrometer for testing soil characteristics is described. The penetrometer is composed of a handle, data recording, and probe components detachably joined together. The data recording component has an easily removed recording drum which rotates according to the downward force applied on the handle, and a stylus means for marking the drum along its height according to the penetration depth of probe into the soil
Rotor redesign for a highly loaded 1800 ft/sec tip speed fan. 1: Aerodynamic and mechanical design report
A quasi three dimensional design system and multiple-circular-arc airfoil sections were used to design a fan rotor. An axisymmetric intrablade flow field calculation modeled the shroud of an isolated splitter and radial distribution. The structural analysis indicates that the design is satisfactory for evaluation of aerodynamic performance of the fan stage in a test facility
Transparency and the Marketplace for Student Data
Student lists are commercially available for purchase on the basis of ethnicity, affluence, religion, lifestyle, awkwardness, and even a perceived or predicted need for family planning services. This study seeks to provide an understanding of the commercial marketplace for student data and the interaction with privacy law. Over several years, Fordham CLIP reviewed publicly-available sources, made public records requests to educational institutions, and collected marketing materials received by high school students. The study uncovered and documents an overall lack of transparency in the student information commercial marketplace and an absence of law to protect student information.https://ir.lawnet.fordham.edu/clip/1003/thumbnail.jp
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