Projection transparencies from printed material

Method for preparing project transparencies, or view graphs, permits the use of almost any expendable printed material, pictures, charts, or text, in unlimited color or black and white. The method can be accomplished by either of two techniques, with a slight difference in materials

Application of optimal control theory to the design of the NASA/JPL 70-meter antenna servos

The application of Linear Quadratic Gaussian (LQG) techniques to the design of the 70-m axis servos is described. Linear quadratic optimal control and Kalman filter theory are reviewed, and model development and verification are discussed. Families of optimal controller and Kalman filter gain vectors were generated by varying weight parameters. Performance specifications were used to select final gain vectors

Participation in Conservation Programs by Targeted Farmers: Beginning, Limited-Resource, and Socially Disadvantaged Operators' Enrollment Trends

Beginning, limited-resource, and socially disadvantaged farmers make up as much as 40 percent of all U.S. farms. Some Federal conservation programs contain provisions that encourage participation by such “targeted” farmers and the 2008 Farm Act furthered these efforts. This report compares the natural resource characteristics, resource issues, and conservation treatment costs on farms operated by targeted farmers with those of other participants in the largest U.S. working-lands and land retirement conservation programs. Some evidence shows that targeted farmers tend to operate more environmentally sensitive land than other farmers, have different conservation priorities, and receive different levels of payments. Data limitations preclude a definitive analysis of whether efforts to improve participation by targeted farmers hinders or enhances the conservation programs’ ability to deliver environmental benefits cost effectively. But the different conservation priorities among types of farmers suggest that if a significantly larger proportion of targeted farmers participates in these programs, the programs’ economic and environmental outcomes could change.Conservation programs, Environmental Quality Incentives Program (EQIP), Conservation Reserve Program (CRP), Wetlands Reserve Program (WRP), beginning farmers, limited-resource producers, socially disadvantaged farmers and ranchers, Environmental Economics and Policy, Farm Management, Financial Economics, Food Consumption/Nutrition/Food Safety, Food Security and Poverty, Land Economics/Use, Production Economics, Research and Development/Tech Change/Emerging Technologies,

Optimal monopoly investment and capacity utilization under random demand

Unique value-maximizing programs of irreversible capacity investment and capacity utilization are described and shown to exist under general conditions for monopolist exhibiting capital adjustment costs and serving random consumer demand for a nondurable good over an infinite horizon. Stationary properties of these programs are then fully characterized under the assumption of serially independent demand disturbances. Optimal monopoly behavior in this case includes acquisition of a constant and positive level of capacity, the maintenance of a positive expected value of excess capacity in each period, and an asymmetrical response of price to unanticipated fluctuations in consumer demand. Under a general form of Markovian demand, the effect of uncertainty on irreversible capacity investment is also described in terms of the discounted flow of expected revenue accruing to the marginal unit of existing capacity and the option value of deferring the acquisition of additional capital. The option value of deferring such acquisition, created by the irreversibility of capacity investment, is characterized directly in terms of the value function of the firm, and is then shown to be zero in a stationary equilibrium with serially independent demand disturbances. The response of investment to increase demand uncertainty depends, as a result, directly on the properties of the marginal revenue product of capital. A non-negative response of optimal capacity to increased uncertainty in market demand is demonstrated for a general class of aggregate consumer preferences.Industrial capacity

Disentangling the complex association between female genital cutting and HIV among Kenyan women

Female genital cutting (FGC) is a widespread cultural practice in Africa and the Middle East, with a number of potential adverse health consequences for women. It was hypothesised by Kun (1997) that FGC increases the risk of HIV transmission through a number of different mechanisms. Using the 2003 data from the Kenyan Demographic and Health Survey (KDHS), this study investigates the potential association between FGC and HIV. The 2003 KDHS provides a unique opportunity to link the HIV test results with a large number of demographic, social, economic and behavioural characteristics of women, including women’s FGC status. It is hypothesised that FGC increases the risk of HIV infection if HIV/AIDS is present in the community. A multilevel binary logistic regression technique is used to model the HIV status of women, controlling for selected individual characteristics of women and interaction effects. The results demonstrate evidence of a statistically significant association between FGC and HIV, after controlling for the hierarchical structure of the data, potential confounding factors, and interaction effects. The results show that women who had had FGC and a younger or the same age first union partner have higher odds of being HIV positive than women with a younger or same age first union partner but without FGC; whereas women who had had FGC and an older first union partner have lower odds of being HIV positive than women with an older first union partner but without FGC. The findings suggest the behavioural pathway of association between FGC and HIV as well as an underlying complex interplay of bio-behavioural and social variables being important in disentangling the association between FGC and HIV

Additional support for the TDK/MABL computer program

An advanced version of the Two-Dimensional Kinetics (TDK) computer program was developed under contract and released to the propulsion community in early 1989. Exposure of the code to this community indicated a need for improvements in certain areas. In particular, the TDK code needed to be adapted to the special requirements imposed by the Space Transportation Main Engine (STME) development program. This engine utilizes injection of the gas generator exhaust into the primary nozzle by means of a set of slots. The subsequent mixing of this secondary stream with the primary stream with finite rate chemical reaction can have a major impact on the engine performance and the thermal protection of the nozzle wall. In attempting to calculate this reacting boundary layer problem, the Mass Addition Boundary Layer (MABL) module of TDK was found to be deficient in several respects. For example, when finite rate chemistry was used to determine gas properties, (MABL-K option) the program run times became excessive because extremely small step sizes were required to maintain numerical stability. A robust solution algorithm was required so that the MABL-K option could be viable as a rocket propulsion industry design tool. Solving this problem was a primary goal of the phase 1 work effort

Kiloparsec-scale Simulations of Star Formation in Disk Galaxies. IV. Regulation of Galactic Star Formation Rates by Stellar Feedback

Star formation from the interstellar medium of galactic disks is a basic process controlling the evolution of galaxies. Understanding the star formation rate in a local patch of a disk with a given gas mass is thus an important challenge for theoretical models. Here we simulate a kiloparsec region of a disk, following the evolution of self-gravitating molecular clouds down to subparsec scales, as they form stars that then inject feedback energy by dissociating and ionizing UV photons and supernova explosions. We assess the relative importance of each feedback mechanism. We find that H2-dissociating feedback results in the largest absolute reduction in star formation compared to the run with no feedback. Subsequently adding photoionization feedback produces a more modest reduction. Our fiducial models that combine all three feedback mechanisms yield, without fine-tuning, star formation rates that are in excellent agreement with observations, with H2-dissociating photons playing a crucial role. Models that only include supernova feedback—a common method in galaxy evolution simulations—settle to similar star formation rates, but with very different temperature and chemical states of the gas, and with very different spatial distributions of young stars

Testing the Resolving Power of 2-D K^+ K^+ Interferometry

Adopting a procedure previously proposed to quantitatively study two-dimensional pion interferometry, an equivalent 2-D chi^2 analysis was performed to test the resolving power of that method when applied to less favorable conditions, i.e., if no significant contribution from long lived resonances is expected, as in kaon interferometry. For that purpose, use is made of the preliminary E859 K^+ K^+ interferometry data from Si+Au collisions at 14.6 AGeV/c. As expected, less sensitivity is achieved in the present case, although it still is possible to distinguish two distinct decoupling geometries. The present analysis seems to favor scenarios with no resonance formation at the AGS energy range, if the preliminary K^+ K^+ data are confirmed. The possible compatibility of data with zero decoupling proper time interval, conjectured by the 3-D experimental analysis, is also investigated and is ruled out when considering more realistic dynamical models with expanding sources. These results, however, clearly evidence the important influence of the time emission interval on the source effective transverse dimensions. Furthermore, they strongly emphasize that the static Gaussian parameterization, commonly used to fit data, cannot be trusted under more realistic conditions, leading to distorted or even wrong interpretation of the source parameters!Comment: 11 pages, RevTeX, 4 Postscript figures include

Model independent shape analysis of correlations in 1, 2 or 3 dimensions

A generic, model-independent method for the analysis of the two-particle short-range correlations is presented, that can be utilized to describe e.g. Bose-Einstein (HBT or GGLP), statistical, dynamical or other short-range correlation functions. The method is based on a data-motivated choice for the zero-th order approximation for the shape of the correlation function, and on a systematic determination of the correction terms with the help of complete orthonormal set of functions. The Edgeworth expansion is obtained for approximately Gaussian, the Laguerre expansion for approximately exponential correlation functions. Multi-dimensional expansions are also introduced and discussed.Comment: Latex, 15 pages, uses epsfig.sty elsart.sty, misprints correcte