Gas leak detector is simple and inexpensive

Pressure sensor monitors small gas leaks in piping and pressure vessels. A combination of a paper ribbon and adhesive plastic tape is used to cover the area to be monitored and the pressure sensor is placed over a hole in the tape and paper

Optical inspection tool for interior surfaces of fluid lines

Specialized tool enables visual inspection of interior bore surfaces of pipe lines having sharp bends and blind runs. Adjustable, hinged optical head permits viewing of bore surfaces at angles from 0 deg to 115 deg to the principal axis of the sight tube

Rotary-knife stripper facilitates removal of X-ray film from pack

Rotary-knife stripper facilitates removal of X ray film from the daylight pack paper sleeve. The new stripper is rectangular, approximately 4 inches wide, 5 inches high, and 7 inches long

Simultaneous assessment of CO2 sensitivity in the respiratory network and its neurons

This work was funded by the National Science Foundation IOS-1 022442

Futures planning, parental expectations and sibling concern for people who have a learning disability

The aim of this questionnaire was to explore the existence of future plans, parental expectation and sibling concern regarding people who have a learning disability. A questionnaire was sent via email to siblings of people who have a learning disability. 21 completed questionnaires were returned and responses were anaylsed using descriptive statistics and thematic analysis. A full discussion regarding sibling support was reported to have taken place by 12 (57%) of respondents, 7 (33%) stated this discussion had not taken place and 2 (9%) were unsure. 12 (57%) of participants reported no clear future plan however where a plan did exist, 7 (33%) of respondents claimed it was fully agreeable to both them and their parents. 11 (52%) of respondents reported no difference between their wishes regarding their future role and parental wishes. Key themes generated were; satisfaction with services, parental influence, sibling concern about the future, futures planning, the impact of the disabled person upon sibling lives and siblings needs. Further qualitative exploration into the personal wishes, reality and parental expectations for future support of siblings of adults who have a learning disability is required. Keywords: adult siblings, futures planning, learning disability, parental expectatio

YIELD BENEFIT OF CORN EVENT MON 863

Data from field experiments are used to estimate the yield benefit of corn hybrids containing event MON 863 relative to nontransgenic corn hybrids without corn rootworm control and with a soil insecticide for corn rootworm control. Over typical ranges for corn rootworm population pressure, event MON 863 provides a yield benefit of 9-28% relative to no control and of 1.5-4.5% relative to control with a soil insecticide. For a reasonable range of prices and yields, the value of the event MON 863 yield benefit is $25-$75/ac relative to no control and $4-$12/ac relative to control with a soil insecticide, depending on corn rootworm pressure. Because of the low correlation between yield loss and the root rating difference, a common empirical finding when estimating yield loss with root ratings, the 95% confidence intervals around these averages are quite wide. Though on average, event MON 863 has substantial value, the wide confidence intervals imply that farmers will see a wide variety of actual performance levels in their fields. This uncertainty in the realized yield benefit is not due to any property of event MON 863, but rather due to the inherent randomness in the numerous environmental and agronomic factors determining a corn plant's yield and yield response to corn rootworm larval feeding damage.Crop Production/Industries,

ADDITIVE VERSUS PROPORTIONAL PEST DAMAGE FUNCTIONS: WHY ECOLOGY MATTERS

Economic analyses of pests typically assume damage is either additively separable from pest free yield or proportional to it. This paper describes the ecological assumptions required for additive and proportional damage functions to demonstrate that both specifications are reasonable. Ecological research supports a proportional damage function for competitive pests such as weeds, while for insect pests the appropriate damage function depends on the level of pest free yield. Theoretical analysis identifies differences between additive and proportional damage functions in terms of the impact of pest control on output variance and the concavity of output in the pest control input.Pest Economics, Damage Function, Damage Control, Risk Reducing Input, Increasing Returns, Functional Response, Crop Production/Industries, Environmental Economics and Policy,

The number of nilpotent semigroups of degree 3

A semigroup is \emph{nilpotent} of degree 3 if it has a zero, every product of 3 elements equals the zero, and some product of 2 elements is non-zero. It is part of the folklore of semigroup theory that almost all finite semigroups are nilpotent of degree 3. We give formulae for the number of nilpotent semigroups of degree 3 with $n\in\N$ elements up to equality, isomorphism, and isomorphism or anti-isomorphism. Likewise, we give formulae for the number of nilpotent commutative semigroups with $n$ elements up to equality and up to isomorphism

Estimating Soil Erosion and Fuel Use Changes and Their Monetary Values with AGSIM: A Case Study for Triazine Herbicides

This technical report describes a method to use the AGSIM policy model to estimate changes in soil erosion and diesel fuel consumption for tillage that result from agricultural policy changes. This report uses triazine herbicides as a case study to explain the development of the method and illustrate its use. The method assumes farmers shift their adoption of different tillage systems as a result of the agricultural policy being examined. Based on these shifts in tillage adoption rates, changes in farmer costs, erosion rates, and consumption of diesel fuel for tillage occur. The changes in farm costs are used as input by AGSIM, along with other changes in costs and/or yields due to the agricultural policy being examined. Based on these inputs, AGSIM then projects crop acreage and prices, as well as changes in consumer surplus, that would occur as a result of the policy. Based on projected crop acreage changes, the method estimates changes in soil erosion and consumption of diesel fuel for tillage, as well as the monetary value of soil erosion changes and the carbon dioxide emission changes resulting from the fuel use changes. As an illustration of the method, this report presents an updated assessment of the benefits of triazine herbicides to the U.S. economy. For the base year of 2009, this assessment finds that triazine herbicides provide total benefits to the U.S. economy of $3.8 to$4.8 billion per year. Because the triazine herbicides increase the total supply of corn and sorghum, which decreases grain prices, most of these benefits accrue to consumers, especially the livestock and ethanol industries that are major users of corn. These consumer benefits are the sum of the benefits flowing to everyone along the supply chain--livestock farmers, processors and handlers, distributors, retailers, and final consumers. Triazine herbicides also reduce the use of tillage for crop production and the conversion of land to crop production, which reduces soil erosion from U.S. cropland by 56 to 85 million tons per year. Based on these reductions, triazine herbicides provide $210 to$350 million per year in benefits from reduced soil erosion as part of this total benefit to the U.S. economy. In addition, triazine herbicides reduce consumption of diesel fuel for tillage by 18 to 28 million gallons per year, implying a decrease in carbon dioxide emissions of 180,000 to 280,000 metric tons per year. This total benefit of $3.8 to$4.8 billion is a lower bound on the full value of triazine herbicides to the U.S. economy, because several benefits are not accounted for in this assessment. Among the most substantial benefits missing from this assessment are estimates of the resistance management benefits of triazine herbicides for other herbicides and crops, environmental benefits other than reduced soil erosion, and the benefits to crops not modeled by AGSIM (e.g., sweet corn, sugarcane, citrus, grapes, and other fruits and nuts).

The Structure of a Graph Inverse Semigroup

Given any directed graph E one can construct a graph inverse semigroup G(E), where, roughly speaking, elements correspond to paths in the graph. In this paper we study the semigroup-theoretic structure of G(E). Specifically, we describe the non-Rees congruences on G(E), show that the quotient of G(E) by any Rees congruence is another graph inverse semigroup, and classify the G(E) that have only Rees congruences. We also find the minimum possible degree of a faithful representation by partial transformations of any countable G(E), and we show that a homomorphism of directed graphs can be extended to a homomorphism (that preserves zero) of the corresponding graph inverse semigroups if and only if it is injective.Comment: 19 pages; corrected errors, improved organization, strengthened a result (Theorem 20), added reference