Transient analysis of bodies with moving boundaries using NASTRAN

A scheme is presented which allows the modeling of a moving boundary with NASTRAN NOLIN cards. Various aspects and limitations of the approach are explained. Recommendations are given as to the procedure to be used in implementing the method

Use of Urea for Crop Production in Kentucky

Current trends indicate that urea will become the major source of solid and liquid N fertilizer in the future. Although urea has several advantages over other N fertilizers, especially in manufacturing, transporting, and marketing, there are some potential agronomic problems that farmers should keep in mind when using urea

Energy Conservation in Corn Production

On-farm production of food and fiber uses about 3% of the annual U.S. energy consumption. About one-third of this energy is directly from fossil fuels used in farm tractors and trucks and for crop drying, while about one-fourth is used in manufacturing and transporting fertilizers. Tillage and N fertilizers are the two largest uses of energy in non-irrigated product ion of crops which are not dried artificially. Thus, the greatest effects of energy conservation can be achieved in these two areas

Returning PIK Land to Grain Production

With the end of the 1983 PIK program, much of the acreage that was in the program will be returned to grain production. Farmers who planted cover crops on their PIK fields in 1983 and who plan to return them to grain production in 1984 will be faced with deciding whether to use no-tillage or conventional tillage. The cover crops will provide mulch for no-tillage crops which may be an asset but can contribute to problems as well. Also, weed problems may be worse on PIK land and more difficult to control with no-tillage than with conventional tillage. The decision on what tillage system to use should basis made on the basis of site-specific conditions of each field. Some thoughts to consider are discussed below

Some Protozoa Found in the Faeces of Cattle

A microscopic investigation of the faeces of cattle was undertaken in search of possible cyst forms of the numerous species of ciliates which inhabit the rumen and reticulum of these animals. Of the various workers who have searched for the cysts of these protozoa only one, Liebetanz (1910), reports success. His technique, however, was so open to adverse criticism, and his figures so unconvincing, that it is doubtful if even he really saw cystic forms

LOX/GOX mechanical impact tester assessment

The performances of three existing high pressure oxygen mechanical impact test systems were tested at two different test sites. The systems from one test site were fabricated from the same design drawing, whereas the system tested at the other site was of different design. Energy delivered to the test sample for each test system was evaluated and compared. Results were compared to the reaction rates obtained

ESTIMATING RETURNS TO AGRICULTURAL RESEARCH, EXTENSION, AND TEACHING AT THE STATE LEVEL

The majority of decisions concerning investment and allocation of public funds for agricultural research, extension, and teaching (RET) are made at the state-level, while most of the quantitative RET evaluations are made on a national basis. This paper illustrates an approach for conducting a disaggregated state-level evaluation of agricultural research, extension, and teaching. Ridge regression is employed to handle multicollinearity problems.Teaching/Communication/Extension/Profession,

Returning CRP Land to Grain Production

Land that was contracted into the Conservation Reserve Program (CRP) was committed to the program for 10 years. The first contracts expire in September 1995, but USDA has already authorized a one-year extension of those contracts. Unless Congress extends the program in the 1995 Farm Bill the contracts will begin expiring on September 30, 1996, as the 10- year period elapses, and continuing until all of the acres that were set aside in the program are released. In Kentucky, about 440,000 acres were contracted in the program from 1986 to 1992. Most of the land is highly erodible, and farmers were required to establish and maintain a vegetative cover to protect the soil from erosion. Grasses or grass-legume mixtures were established on about 434,000 acres of this land. The rest was planted to trees or wildlife habitat. A 1993 survey by the Soil and Water Conservation Society indicated that, without extension of the CRP and assuming current commodity prices, 63% of U. S. farmers would return their land to row crop production the first year after their contracts expire. About 23% would continue in grassland for hay or grazing. In the USDA Appalachian region where Kentucky is listed, those estimates are 48% returned to row crops, 23% left in grass, and 13% left in trees. Much of Kentucky, especially western Kentucky, will probably respond more like the Corn Belt region where 73% of CRP acres are expected to be cropped and only 16% will be kept in grass. The crops will be mostly com and soybeans

Arachidonic Acid Release and Catecholamine Secretion from Digitonin-Treated Chromaffin Cells: Effects of Micromolar Calcium, Phorbol Ester, and Protein Alkylating Agents

The relationship between catecholamine secretion and arachidonic acid release from digitonin-treated chromaffin cells was investigated. Digitonin renders permeable the plasma membranes of bovine adrenal chromaffin cells to Ca 2+ , ATP, and proteins. Digitonin-treated cells undergo exocytosis of catecholamine in response to micromolar Ca 2+ in the medium. The addition of micromolar Ca 2+ to digitonin-treated chromaffin cells that had been prelabeled with [ 3 H]arachidonic acid caused a marked increase in the release of [ 3 H]arachidonic acid. The time course of [ 3 H]arachidonic acid release paralleled catecholamine secretion. Although [ 3 H]arachidonic acid release and exocytosis were both activated by free Ca 2+ in the micromolar range, the activation of [ 3 H]arachidonic acid release occurred at Ca 2+ concentrations slightly lower than those required to activate exocytosis. Pretreatment of the chromaffin cells with N -ethylmaleimide (NEM) or p -bromophenacyl bromide (BPB) resulted in dose-dependent inhibition of 10 Μ M Ca 2+ -stimulated [ 3 H]arachidonic acid release and exocytosis. The IC 50 of NEM for both [ 3 H]arachidonic acid release and exocytosis was 40 Μ M. The IC 50 of BPB for both events was 25 Μ M. High concentrations (5–20 m M ) of Mg 2+ caused inhibition of catecholamine secretion without altering [ 3 H]arachidonic acid release. A phorbol ester that activates protein kinase C, 12- O -tetradecanoylphorbol-13-acetate (TPA), caused enhancement of both [ 3 H]arachidonic acid release and exocytosis. The findings demonstrate that [ 3 H]arachidonic acid release is stimulated during catecholamine secretion from digitonin-treated chromaffin cells and they are consistent with a role for phospholipase A 2 in exocytosis from chromaffin cells. Furthermore the data suggest that protein kinase C can modulate both arachidonic acid release and exocytosis.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65534/1/j.1471-4159.1985.tb07140.x.pd

The Relationship Between Arachidonic Acid Release and Catecholamine Secretion from Cultured Bovine Adrenal Chromaffin Cells

Increased arachidonic acid release occurred during activation of catecholamine secretion from cul- tured bovine adrenal medullary chromaffin cells. The nicotinic agonist l,l-dimethyl-4-phenylpiperazinium (DMPP) caused an increased release of prcincubated [ 3 H]arachidonic acid over a time course which corre- sponded to the stimulation of catecholamine secretion. Like catecholamine secretion, the DMPP-induced [ 3 H]arachidonic acid release was calcium-dependent and was blocked by the nicotinic antagonist mecamylamine. Depolarization by elevated K + , which induced catechol amine secretion, also stimulated arachidonic acid release. Because arachidonic acid release from cells probably re- sults from phospholipase A 2 activity, our findings indicate that phospholipase A 2 may be activated in chromaffin cells during secretion.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66068/1/j.1471-4159.1984.tb06690.x.pd