Decoupling Farm Payments: Experience in the U.S., Canada, and Europe

Commodity payments in Europe and North America are production based, encouraging greater chemical use and cropping area. Thus, each region undermines the other’s price supports at the expense of the environment. Countries can, however, sever the link between yield levels and payments. Allowing farmers to exit agriculture poses challenges for the US, but perhaps not for Canada and the EU.decoupling, liberalizing trade, environment, flexibility

Severing the Link between Farm Program Payments and Farm Production: Motivation, International Efforts, and Lessons

Agricultural and Food Policy, International Relations/Trade,

Earth History Visualization System

Time Scale Creator (TSCreator), a geological chart generator, displays any portion of Earth history including chemo- magneto-, and other aspects. TSCreator is used by many universities, petroleum companies, and international geological surveys. In order to improve the quality of Time Scale Creator, tools were developed to provide users with more friendly graphical user interfaces (GUIs), accurate scaling of specific isotope, internationalization of data input and output, and smart depth scaling in wells to age conversion. To implement such tools, research for algorithm and common methods was basically done by searching articles online and reading posts on forums for Java developers. Toggle buttons indicating moving status of time lines were inserted into the tool bar of Crossplot frame. Internationalization was improved by accepting both European and American number formats in text boxes and entries of data packs. Strontium, an isotope used to interpret rates of mountain belt uplift and continental drift, was given four decimal place precision whereas other isotopes have standard two to three decimal places precision. Finally, an algorithm for naturally dividing depth range was inserted for depth scales in Depth/ Age Conversion. The Depth-Age system will be used with university lab modules. These developed tools enhance user experience and performance of Time Scale Creator. The improvements were already used by two university workshops in China, and will be used by petroleum-exploration workshops in Australia. An article about this system is planned for publication

Geographies of landscape aesthetics : mapping landscape terminology in digitised historical travel accounts of Loch Lomond and the Trossachs

Acknowledgements Ogg.: Conceptualisation, Methodology, Formal Analysis, Investigation, Visualisation, Writing –Original Draft Preparation. Wartmann.: Conceptualisation, Supervision, Writing – Review & Editing.Peer reviewedPublisher PD

Selmer Groups in Twist Families of Elliptic Curves

The aim of this article is to give some numerical data related to the order of the Selmer groups in twist families of elliptic curves. To do this we assume the Birch and Swinnerton-Dyer conjecture is true and we use a celebrated theorem of Waldspurger to get a fast algorithm to compute $$. Having an extensive amount of data we compare the distribution of the order of the Selmer groups by functions of type $\alpha \frac{(\log \log (X))^{1+\varepsilon}}{\log (X)}$ with $\varepsilon$ small. We discuss how the "best choice" of $\alpha$ is depending on the conductor of the chosen elliptic curves and the congruence classes of twist factors.Comment: to appear in Quaestiones Mathematicae. 16 page

The reproduction and mode of spread of sago pondweed (Potamogeton pectinatus L.) in irrigation system

Nine experiments were conducted during 1964 and 1965 to study the methods of reproduction and mode of spread of sago pondweed (Potamogeton pectinatus) in irrigation systems. Frequent treatments of sago pondweed foliage with aromatic solvent greatly reduced the number of tubers in the substratum of an irrigation canal. However, complete eradication of all tubers in one irrigation season was not obtained. Ecological investigations revealed that sago pondweed was capable of invading and becoming established in new irrigation channels in one season. The propagules responsible for the establishment of new infestations were tubers and plant fragments. Considerable numbers of sago pondweed seed were transported into the new channels by the water, but no seedlings were found. Sago pond-weed tubers survived freezing temperatures under field conditions. Subsequent studies in the laboratory showed that sago pondweed tubers could become somewhat hardened or conditioned to withstand freezing temperatures. Removal of the parent tuber did not affect the survival of emerged shoots nor did it prevent the growth of excised sprout tips. The main portion of the tuber appeared to have a function other than initiating growth. The study of shoot emergence from tubers indicated a relationship between the weight of the tuber and the depth from which the shoot would emerge. The main portion of the tuber, whose dry weight consists primarily of carbohydrates, may function as a food reserve enabling the shoot to emerge from a considerable depth in the soil. Sago pondweed seeds that had overwintered in a canal bottom gave 15 percent germination in a greenhouse aquarium after a 50-day period. Seeds that had passed through the digestive tracts of wild-ducks germinated abundantly. However, if the seeds were held in the digestive tract for more than three days, no germination occurred. The storage of sago pondweed seeds at different conditions of temperature and moisture for different periods of time resulted in significant differences in the percentages of germination. Storage of seed in water at 0.0 degrees C. for 12 days resulted in the highest percentage of germination. The seed germination studies indicated that the importance of seed in the spread of sago pondweed in irrigation systems may be underestimated

Sensitization of tumour cells to lysis by virus-specific CTL using antibody-targeted MHC class I/peptide complexes

A number of cell surface molecules with specificity to tumour cells have been identified and monoclonal antibodies (mAb) to some of these antigens have been used for targeting tumour cells in vivo. We have sought to link the powerful effector mechanisms of cytotoxic T-cells with the specificity of mAb, by targeting recombinant HLA class I molecules to tumour cells using an antibody delivery system. Soluble recombinant MHC class I/peptide complexes including HLA-A2.1 refolded around an immunodominant peptide from the HIV gag protein (HLA-A2/gag) were synthesized, and the stability of these complexes at 37°C was confirmed by enzyme-linked immunosorbent assay using a conformation-specific antibody. MHC class I-negative lymphoma cells (Daudi) were labelled with a biotinylated mAb specific for a cell surface protein (anti-CD20) then linked to soluble biotinylated HLA-A2/gag complexes using an avidin bridge. Flow cytometry revealed strong labelling of lymphoma cells with HLA-A2/gag complexes (80-fold increase in mean channel fluorescence). CTL specific for HLA-A2/gag efficiently lysed complex-targeted cells, while control CTL (specific for an HLA-A2.1-restricted epitope of melan-A) did not. Similarly, SK-mel-29 melanoma cells were also efficiently lysed by HLA-A2/gag-specific CTL when HLA-A2/gag complexes were linked to their surface via the HMW-MAA specific anti-melanoma antibody 225.28s. With further consideration to the in vivo stability of the MHC class I/peptide complexes, this system could prove a new strategy for the immunological therapy of cancer. © 2000 Cancer Research Campaig

Magnetic-field dependence of electron spin relaxation in n-type semiconductors

We present a theoretical investigation of the magnetic field dependence of the longitudinal ($T_1$) and transverse ($T_2$) spin relaxation times of conduction band electrons in n-type III-V semiconductors. In particular, we find that the interplay between the Dyakonov-Perel process and an additional spin relaxation channel, which originates from the electron wave vector dependence of the electron $g$-factor, yields a maximal $T_2$ at a finite magnetic field. We compare our results with existing experimental data on n-type GaAs and make specific additional predictions for the magnetic field dependence of electron spin lifetimes.Comment: accepted for publication in PRB, minor changes to previous manuscrip

Metallic Xenon, Molecular Condensates, and Superconductivity

A possibility of explaining the light absorption observed to occur under pressure-induced xenon metallization as due to the transition to the superconducting state is analyzed. The mechanism of the van der Waals bonding is discussed.Comment: LaTeX 2.09 (RevTeX), 4 pages, 4 PostScript figures included in tex