23,821 research outputs found
A survey of the problem and research needs in the coastal zone
Coastal zone oceanography emphasizing pollution and geological processes - bibliograph
The fatigue behavior of materials for the supersonic transport
Crack propagation behavior, residual static strength, and base fatigue strength of supersonic transport skin materia
Machines on Genes: Enzymes that Make, Break and Move DNA and RNA
As the vital information repositories of the cell, the nucleic acids DNA and RNA pose many challenges as enzyme substrates. To produce, maintain and repair DNA and RNA, and to extract the genetic information that they encode, a battery of remarkable enzymes has evolved, which includes translocases, polymerases/replicases, helicases, nucleases, topoisomerases, transposases, recombinases, repair enzymes and ribosomes. An understanding of how these enzymes function is essential if we are to have a clear view of the molecular biology of the cell and aspire to manipulate genomes and gene expression to our advantage. To bring together scientists working in this fast-developing field, the Biochemical Society held a Focused Meeting, âMachines on Genes: Enzymes that Make, Break and Move DNA and RNAâ, at Robinson College, University of Cambridge, U.K., in August 2009. The present article summarizes the research presented at this meeting and the reviews associated with the talks which are published in this issue of Biochemical Society Transactions
Imaging X-ray spectrometer
An X-ray spectrometer for providing imaging and energy resolution of an X-ray source is described. This spectrometer is comprised of a thick silicon wafer having an embedded matrix or grid of aluminum completely through the wafer fabricated, for example, by thermal migration. The aluminum matrix defines the walls of a rectangular array of silicon X-ray detector cells or pixels. A thermally diffused aluminum electrode is also formed centrally through each of the silicon cells with biasing means being connected to the aluminum cell walls and causes lateral charge carrier depletion between the cell walls so that incident X-ray energy causes a photoelectric reaction within the silicon producing collectible charge carriers in the form of electrons which are collected and used for imaging
ENVIRONMENTAL POLICY INFLUENCES ON LIVESTOCK STOCKING AND LOCATION DECISIONS
This paper explores the relationship between state level environmental regulations and stocking and location decisions in the U.S livestock and poultry industry (beef, chicken, dairy and hogs). Rather than conduct this analysis on a species-by-species basis, we choose to focus upon the overall size of the livestock industry (expressed in animal units) and the size of industry found on large, medium and small operations by state (48) and over time (28 yrs). Results indicate that industry may drive policy rather than the converse. However, since we also find that existing policy rules have differential impacts on the industry by operation size, we conclude that structural change in the industry may be driven in part by size or legal structure discriminating regulations.Demand and Price Analysis, Livestock Production/Industries,
Gratings photowritten in ion-exchanged glass channel waveguides
Gratings are photowritten in ion-exchanged glass channel waveguides. The transmission of these waveguides shows a rejection dip of almost 20dB. The polarisation dependence of these waveguide gratings is measured and discussed
Grating formation in BGG31 glass by UV exposure
A three-dimensional index variation grating in bulk BGG31 glass written using neither hydrogen loading nor germanium doping is demonstrated. This material is useful for fabricating ion-exchanged waveguides, and its photosensitivity to ultraviolet (UV) radiation at 248nm has not been previously explored. Intensity measurements of the Bragg diffracted spots indicated a maximum index variation (Delta n) of similar to 4 x 10(-5)
Numerical Studies of the Compressible Ising Spin Glass
We study a two-dimensional compressible Ising spin glass at constant volume.
The spin interactions are coupled to the distance between neighboring particles
in the Edwards-Anderson model with +/- J interactions. We find that the energy
of a given spin configuration is shifted from its incompressible value, E_0, by
an amount quadratic in E_0 and proportional to the coupling strength. We then
construct a simple model expressed only in terms of spin variables that
predicts the existence of a critical value of the coupling above which the
spin-glass transition disappears.Comment: REVTeX, 4 pages, 4 figures. Submitted to Phys. Rev. Let
The results of a cattle feeding test
The problem of most vital importance to the cattle feeder of the middle west at the present day is, how to produce beef more economically. The marked advance in the value of farm lands and the strenuous competition of the range territory coupled with the high priced feeding-stuffs have materially changed conditions from what they were less than two decades ago. Can he afford to feed fifty-five or sixty cent corn to cattle and hope to realize a profit? Can he, by the addition of some by-product or condimental food, secure better returns from the corn fed? These have been during the past year and are at the present day, very perplexing problems to the feeder. He has heard it stated that some of the by-products of corn, flaxseed or cottonseed when fed with corn will give much better returns than corn alone. He has been informed by the âstock food manâ that a little stock food fed in conjunction with corn will increase his returns from fifty to one hundred per cent., this being due to the fact that the stock food has the power of increasing the appetite of the animal also of stimulating the digestive organs to such an extent that a much larger proportion of the corn consumed by the animal is digested
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