17,984 research outputs found
Incidence and Location of Eastern Pineshoot Borer Damage in Some Scotch Pine Christmas Tree Plantations in Michigan (Lepidoptera: Olethreutidae)
A survey of Christmas tree farms in Michigan revealed that 26% of the Scotch pine Christmas trees have one or more shoots injured by the eastern pineshoot borer, Eucosma gloriola Heinrich. Most attacks occurred on lateral branches in the top half of the tree. Only 2% of the observed trees had pineshoot borer injury on the terminal leader. Control except for normal shearing, was not recommended for most plantations
Truth-telling and the Role of Limited Liability in Costly State Verification Loan Contracts
Recent literature has considered the form of loan contract between two or more risk neutral parties where the revelation principle is inappropriate due to the lack of commitment to an auditing policy by the lender. The privately informed debtor has a stochastic return; once he knows the state realisation, auditing and cheating are determined as Nash equilibria. The literature assumes that this leads to randomised cheating and auditing. In this paper we verify that the contract may involve this randomisation; but that it may also involve truthtelling with random auditing and one or more investors in line with Persons (1996); or a single state independent repayment with no auditing. We define conditions on the state observation cost and the distribution of returns which determine which of these three forms of contract is optimal. We find that under unlimited liability when the loan size is fixed the two investor truthtelling contract dominates all the other forms; and that this is also true when the loan size is optimally chosen. On the other hand under limited liability if the cost of observation is large relative to the lowest state revenue, the random auditing contract or a constrained two investor truthtelling contract may be optimal. The limited liability condition in the constrained truthtelling contracts forces the level of finance to be higher than under unlimited liability.loan contracts, costly state verification, commitment, limited liability
Preparing oxidizer coated metal fuel particles
A solid propellant composition of improved efficiency is described which includes an oxidizer containing ammonium perchlorate, and a powered metal fuel, preferably aluminum or beryllium, in the form of a composite. The metal fuel is contained in the crystalline lattice framework of the oxidizer, as well as within the oxidizer particles, and is disposed in the interstices between the oxidizer particles of the composition. The propellant composition is produced by a process comprising the crystallization of ammonium perchlorate in water, in the presence of finely divided aluminum or beryllium. A suitable binder is incorporated in the propellant composition to bind the individual particles of metal with the particles of oxidizer containing occluded metal
Racism on Campus: An Exploratory Analysis of Black-White Perceptions in the South
Racism has been a persistent problem in American society. Sociologists refer to racism as unfair treatment of an individual or a group solely on the basis of race.[1] It may be covert or overt, and it may be expressed on an individual level when a person consciously or unconsciously discriminates against another person. Racism may also be expressed on an institutional level, when rules, policies and practices of organizations and/or institutions discriminate against an individual or a group.[2
Alternatives to the Gypsy Moth Eradication Program in Michigan
Responding to questions of what the gypsy moth, Porthetria dispar, would do in Michigan forests, a computer simulation model was constructed. The model consisted of three subunits: a submodel of gypsy moth population dynamics, a submodel of forest growth and a submodel of tree defoliation and mortality. Several different policies were simulated for an 80 year period. The eradication policy now employed in Michigan failed due to survival of small portions of the population. Allowing the gypsy moth to become established in Michigan forests and then responding by spraying when defoliation is visible provided a policy with the least economic and environmental cost
Ultra-dense phosphorus in germanium delta-doped layers
Phosphorus (P) in germanium (Ge) delta-doped layers are fabricated in
ultra-high vacuum by adsorption of phosphine molecules onto an atomically flat
clean Ge(001) surface followed by thermal incorporation of P into the lattice
and epitaxial Ge overgrowth by molecular beam epitaxy. Structural and
electrical characterizations show that P atoms are confined, with minimal
diffusion, into an ultra-narrow 2-nm-wide layer with an electrically-active
sheet carrier concentration of 4x10^13 cm-2 at 4.2 K. These results open up the
possibility of ultra-narrow source/drain regions with unprecedented carrier
densities for Ge n-channel field effect transistors
An electric quadrupole transition in the A1pi - X1sigma system of CO
Electric quadrupole transition in carbon monoxid
Parasitism of Early Instar Jack Pine Budworm (Lepidoptera: Tortricidae) by Apanteles Spp. (Hymenoptera: Braconidae) and Glypta Fumiferanae (Hymenoptera: Ichneumonidae)
Glypta fumiferanae and two species of Apanteles parasitized 1st-4th instar jack pine bud worm (Choristoneura pinus). Apparent parasitism of budworm in four Michigan populations ranged from 10.6 to 30.9% for A. fumiferanae, 4.3-16.4% for A. morrisi, and 2.1-9.1 % for G.fumiferanae. A. morrisi probably parasitized 3rd-4th instar jack pine bud worm. Based on the results obtained, it is suggested that sampling overwintering budworm larvae is appropriate for estimating apparent parasitism by A. fumiferanae and G. fumiferanae. Sampling budworm larvae at ca. 500 degree-days (base 8.9°C) is appropriate for estimating apparent parasitism by A. morrisi
Debt and Risk Preference: A Household Level Analysis
We explore the relationship between risk preference and the level of unsecured debt at the household level within the context of a two period theoretical framework, which predicts that debt is a function of risk aversion. We test the predictions of our theoretical framework for a sample of households drawn from the U.S. Panel Study of Income Dynamics (PSID) and the U.S. Survey of Consumer Finances (SCF). Using a sequence of questions from the 1996 PSID and the 1989 to 2004 SCF, we construct measures of risk preference allowing us to explore the implications of interpersonal differences in risk preference for the accumulation of unsecured debt at the household level. Our empirical findings, which accord with our theoretical priors, suggest that risk preference is an important determinant of the level of unsecured debt acquired at the household level with risk aversion serving to reduce the level of unsecured debt accumulated by households
Michigan\u27s Cooperative Forest Pest Management Program, A Team Approach to Improving Forest Management
A forest management team was organized in the late 1970\u27s by cooperative efforts of Michigan\u27s universities. the Michigan Department of Natural Resources, and the USDA Forest Service.The goals were to devise new technologies, transfer available technology, and service and management alternatives to forest land managers in Michigan. The program throughout has emphasized forest management rather than pest management for prevention and control of pests. Dissemination of pest management information has been of importance and new research results have gone directly to land managers for immediate use. The team participates in forest compartmental reviews and helps prescribe management plans for land parcels, thus providing for preventative pest management. Services and management recommendations are provided mostly through forest pest specialists located in the field. They feed back results and problems to researchers and extension specialists of the team for further input. Preventive management information used by by local managers in recent years has nearly paid the cost of the program. Plans are to broaden the team effort by cooperating with organizations and in adjacent states through a computer network system and by other means
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