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The use of hedging with commodity futures markets to reduce the price risk in corn production is examined. Both intra-year and inter-year risk are evaluated with different hedging strategies. Strategies involve no hedge, hedge and hold, controlled hedge placement and hold, and in and out hedging. Both technical and forecasting criteria are used to place hedges in the more active strategies. Substantial risk reduction is possible, often without a reduction in price received. Considerable basis risk diminishes the risk reducing properties of a hedge and hold strategy.
Since World War II U.S. Agriculture has seen regional shifts and greater concentration in the production of certain commodities. Technological and infrastructural developments in irrigation, plant varieties, cultivation techniques, transportation, storage, and processing have lowered the barriers of time and space, thus allowing remote regions to compete with and even dominate the traditional production areas. The U.S. potato industry offers an excellent example of this. Processed potatoes have become the dominant food use form and production has shifted westward and become more concentrated both with respect to time and location. In 1947, 44 percent of U.S. potato production was in the seven largest potato states for the fall crop, 35 percent was produced in the nonfall crops, and eight percent was processed. By 1978, 75 percent was produced by the seven leading states for the fall crop, 14 percent in the early nonfall crops, and 59 percent was processed. Because many of these changes involved the adoption of relatively energy intensive techniques, the existence of low and fairly stable energy prices until 1973 aided this change. The increases in energy costs since 1973 raise questions about the long-run stability of recent patterns of production and consumption.
Recent developments on the use of the piezoelectric effect in ZnO nanorod-based p-n junctions for energy harvesting applications are presented. Two types of junctions are used. The first is a hybrid p-n device combining the semiconducting polymer poly(3,4-ethylene-dioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) with ZnO nanorods. The second type of junction is an all-inorganic junction between n-type ZnO nanorods and p-type CuSCN. It is shown that both these diodes can be produced on flexible plastic substrates, which generate a voltage output when bent. The voltage output of the ZnO/PEDOT:PSS diodes are measured across a range of resistive loads while bending to find a maximum power point of 12 μWcm-2 at 4 kΩ. It is shown that a voltage output is also generated when this structure is vibrated acoustically. The ZnO/CuSCN diode is sensitized to sunlight with a Ru-based dye to form a photovoltaic device. It is shown that the device efficiency can be increased by application of acoustic vibrations. This is attributed to the electric field generated by the piezoelectric effect in ZnO affecting the charge-carrier recombination at the ZnO surface.
The effects of pulsed laser irradiation on silicon (111) single crystal thin samples were studied in a ultra-high vacuum transmission electron microscope. Samples were found to cleave along (110) planes under the laser beam. The formation of dislocation networks was also observed. The cleaving did not seem to originate from previously observed defect areas, but from random places, and is believed to be caused by thermal shock from laser beam heating. Bulk defects in the specimens, such as stacking fault tetrahedra and dislocations, were not observed to be affected by the laser treatment.
To determine the anatomic sites and natural history of colonization with gram-negative multidrug-resistant organisms (MDROs).
Prospective, longitudinal cohort study.
Walter Reed Army Medical Center, a 236-bed tertiary care center in Washington, DC.
Deployed subjects (ie, inpatients medically evacuated from Iraq or Afghanistan) or nondeployed subjects admitted to the same hospital.
Consenting patients had 6 anatomic sites cultured every 3 days for 2 weeks and then weekly. Gram-negative organisms resistant to 3 or more classes of antibiotics were considered MDROs. Isolates were genotyped using pulsed-field gel electrophoresis. Clinical data, data on antibiotic use, and clinical culture results were collected.
Of 60 deployed subjects, 14 (23%) were colonized with an MDRO at admission, and 13 (22%) had incident colonization during hospitalization. The groin was the most sensitive anatomic site for detecting MDRO colonization, and all but one subject remained colonized for the duration of their hospitalization. Sixty percent of subjects with incident Acinetobacter colonization and 25% of subjects with incident Klebsiella colonization had strains that were related to those isolated from other subjects. Of 60 nondeployed subjects, 5 (8%) were colonized with an MDRO at admission; all had recent healthcare contact, and 1 nondeployed subject had an isolate related to a strain recovered from a deployed subject.
Colonization with gram-negative MDROs is common among patients with war-related trauma admitted to a military hospital and also occurs among nondeployed patients with recent healthcare contact. The groin is the most sensitive anatomic site for active surveillance, and spontaneous decolonization is rare.
The 1996 Farm Bill marks a new direction for the government in agriculture. By decoupling payments from price levels for crops, it undermines long-run political support for programs. Dairy price supports will end in 2000, and nutrition programs will be on a separate reauthorization schedule from farm programs. Together, these actions should weaken the farm bill coalition, making the remaining programs much more difficult to reauthorize than in earlier years. The 1996 Farm Bill may be the last farm bill of its kind and the beginning of the end to active government involvement in agricultural markets.
Considerable attention has been given to the proper measurement, estimation, and analysis of the technological structure of aggregate U.S. agriculture (Binswanger, Brown, Ray, and Antle). During the last decade, duality theory-motivated studies have also analyzed regional farm production (Saez, and Shumway). Except for the Saez study, no attempt has been made to analyze the farm production structure of the Northeast region.
The twolined chestnut borer, Agrilus bilineatus (Weber) (Coleoptera: Buprestidae), is associated with mortality of stressed oaks in the eastern deciduous forests of North America. Beetles were attracted to stressed trees within hours of the onset of stress. We hypothesized that adult beetles rapidly locate suitable hosts by olfactory detection of tree-released volatiles. Trees with sticky-band traps and vane traps baited with crude steam distillates from inner bark of stressed white oaks, or with combinations of ethanol and oak volatiles, captured significantly more beetles than did water controls. Ethanol alone did not attract significant numbers of A. bilineatus. Eighty-two percent of beetles captured were females. Ethanol-baited traps captured large numbers of Cerambycidae, Scolytidae, and a few Cleridae, and these insects were not attracted to oak volatiles. Sticky-band traps were more effective than vane traps in capturing A. bilineatus and other Buprestidae, but Cerambycidae and Scolytidae were more effectively captured in vane traps. Our results show that A. bilineatus is attracted to oak volatiles but later successional beetles are attracted to ethanol.
An interregional competition model of the U.S. apple industry is constructed. This model includes the consumer products of fresh apples, applesauce and apple juice. The validation of the model showed that it did a good job of estimating consumer's quantity demanded and prices and a reasonable job of estimating utilization. This model was used to study the effects of transportation cost changes on the industry in the short- and intermediate run. The total production and consumption levels changed by moderate amounts with changing transport costs while the utilization of a region's crop was quite sensitive to such changes.
Major increases in energy prices since 1973 have raised considerable interest in the effect of a continuation of these increases on interregional competition. There is speculation in the Northeast that a general increase in energy prices will cause agricultural production to shift closer to the consumers. This production shift supposedly will lead to self-sufficiency in many products which were once grown in the Northeast and are now largely imported from other regions. This paper uses a simple interregional trade model to estimate the possible impact of higher energy prices on interregional competition, and on the Northeast in particular. It does this by assuming values for the relevant variables in the model and estimating the changes in the system. A range of values are used to estimate the sensitivity of the conclusions to the assumptions.
Potatoes suitable for frozen french fries are harvested in the fall and then apportioned for the rest of the year by processors. This involves storage in either fresh or frozen form. Participants in both the fresh and french fry market consider the level of frozen french fry stocks to be an important determinant of activity in these markets and therefore use stock information to form price expectations [Phillips et al., 16–18]. The ability to forecast the future level of stocks with some accuracy would undoubtedly be an additional aid in developing market strategies. This paper provides one means of forecasting frozen french fry stocks.
Decision makers face two opposing forces in the provision of emergency services. Their constituency wants more and better services, but financial considerations limit the quantity and quality of services provided. This classic economic confrontation requires a decision based on the trade-offs between the benefits of protection provided by additional services and the cost of providing these services. Such a decision is needed for ambulance service, fire protection, and law enforcement.
Border Leicester X Suffolk sheep infected with a strain of S. mattheei maintained in hamsters do not develop the same pathological changes as Romney Marsh sheep infected with the same strain of parasite before hamster passage. To determine the cause of this reduced pathogenicity, five Romney Marsh sheep were each infected with 10 000 cercariae of the hamster-passaged parasite and five with 10 000 cercariae of a S. mattheei strain from Onderstepoort, South Africa, passaged exclusively through sheep.
Striking pathological and parasitological differences were found between the two strains. Infection with the “sheep” strain was lethal, whereas infection with the “hamster” strain produced little evidence of clinical disease. By 13 weeks post-infection the mean body weight of the sheep infected with the sheep strain had declined by 15% compared with both the uninfected controls and the sheep infected with the hamster strain, and the mean PCV was lowered to 20% in the sheep strain infected animals. Egg production began at seven weeks with the sheep strain, faecal counts rising to more than 300 e.p.g., whereas only two of the sheep infected with the hamster strain passed eggs in the faeces (at nine weeks) and the maximum egg count was 50 e.p.g. Twice as many adult worms of the sheep strain were recovered, and, although the number of eggs found in the tissues “per worm pair” was not significantly different, overall egg production was higher for the sheep strain; also more of the sheep strain eggs were deposited in the intestines. Similar parasite differences were seen in a supplementary study in mice and it seemed that “attenuation” of the parasite had occurred, presumably due to its maintenance in hamsters. Histopathological observations and faecal egg counts both indicated an inability of hamster strain eggs to penetrate the intestinal lumen; this was probably important in reducing the pathogenicity of the hamster strain.
The number of employed health care personnel in an area is the combined result of factors affecting both demand and supply for health care personnel. When service areas are compared, differences between each area's number of health care personnel are related to differences in health facilities' ability and desire to attract these persons.
At any point in time, the potential supply of health care personnel is fixed. The choice facing this segment of the labor force is between alternative locations or non-participation. The location decision is a function of salary, working conditions and such non-working conditions as cost of living in the community, schools, cultural opportunities, employment opportunities for other family members and general amenities associated with a community.
Irradiated cercariae, irradiated schistosomula, or hcterologous infections were used to vaccinate sheep against Schistosoma mattheei infection. In the first experiment four doses of I04 S. mattheei cercariae irradiated at 6Kr were administered to sheep by percutaneous infection at 4 week intervals. This induced a 74% reduction in a challenge infection compared to control sheep while only 13% protection was achieved in a third group of sheep immunised with normal cercariae of the heterologous parasite S. mansoni. No significant differences were seen in histopathology of the liver of any of the sheep but the pathological changes were more severe in the large and small intestines of sheep vaccinated with the heterologous parasite. In the second experiment with irradiated cercariae only one or two immunising exposures were used. The degree of protection in the adult worm load (9–11%) was not significant and no significant differences were noticed in the pathology of the vaccinated and control animals. In the third experiment four doses of irradiated organisms were used to vaccinate five groups of sheep: 3Kr or 6Kr cercariae were administered by percutaneous infection; 6Kr skin-transformed scbistosomula were administered by intramuscular injection; the same 6Kr skin-transformed schistosomula were given by intravenous injection and 6Kr syringe transformed schistosomula were administered by intramuscular injection. The degree of protection (determined as the reduction in worm burden) achieved by these different procedures was respectively 72%, 61%, 77%, 56% and 78%. These results indicate the possibility of making a live vaccine against ovine schistosomiasis and show that effective immunisation is not dependent on the presence of a mature worm infection or on cercarial penetration of the skin by the immunising infection.