DO TROPICAL FORESTS PROVIDE A SAFETY NET? INCOME SHOCKS AND FOREST EXTRACTION IN MALAWI

We use seasonal household data on income shocks and forest extraction to study how households in Malawi use forests to cope with income shortfalls. In particular, we study household response to receipt of a positive income shock delivered in the form of a technology assistance package. We estimate a random-effects model of forest extraction to examine whether household forest use is responsive to income shocks received in a prior period. We also measure the extent to which households subsequently save out of transitory income. Findings indicate that forest extraction by asset-poor households was more responsive to income shocks than forest extraction by better-off households. Findings also suggest households save out of transitory income, and in the process accumulate physical assets that may reduce their dependence on forests for weathering subsequent income shocks. Results show how policies aimed at poverty alleviation among those living adjacent to tropical forests can also alleviate forest pressure.Resource /Energy Economics and Policy,

An integrated approach to rotorcraft human factors research

As the potential of civil and military helicopters has increased, more complex and demanding missions in increasingly hostile environments have been required. Users, designers, and manufacturers have an urgent need for information about human behavior and function to create systems that take advantage of human capabilities, without overloading them. Because there is a large gap between what is known about human behavior and the information needed to predict pilot workload and performance in the complex missions projected for pilots of advanced helicopters, Army and NASA scientists are actively engaged in Human Factors Research at Ames. The research ranges from laboratory experiments to computational modeling, simulation evaluation, and inflight testing. Information obtained in highly controlled but simpler environments generates predictions which can be tested in more realistic situations. These results are used, in turn, to refine theoretical models, provide the focus for subsequent research, and ensure operational relevance, while maintaining predictive advantages. The advantages and disadvantages of each type of research are described along with examples of experimental results

CONTRACT INCENTIVES AND EXCESSIVE NITROGEN USE IN AGRICULTURE

This study examines incentives for input use under tournament contracts. We analyze implications of contract design for nitrate-based environmental externalities generated by agricultural producers. Outcomes are compared from contracts awarded by tournament to those from fixed-payment contracts. Our findings show contract insecurity can distort input use. The model developed in this analysis is applied to a region of the U.S. where tournament-based production is prevalent and groundwater contamination is a problem. We find contract insecurity increases nitrogen use by about 12%, resulting in a 17% increase in nitrate leaching. Implications for contract modification to reduce environmental externalities while maintaining contract incentives are discussed.Crop Production/Industries,

Detect and Avoid: Efforts from NASA's UAS Integration into the NAS Project

NASA's Unmanned Aerial Systems (UAS) integration into the National Air Space (NAS) project has been working closely with the FAA and RTCA Special Committee 228 to identify and break down barriers to UAS integration. A focus of this work is on detect and avoid (DAA) technologies. A pilot has responsibility to see and avoid other aircraft and to remain "well clear," using their best judgment (Federal Aviation Regulations (FAR) Sec. 91.113). For UAS to perform this function, the see function is replaced by sensors to detect the other aircraft. Secondly, the pilot judgment of well clear has to be replaced by a mathematical expression. For Phase 1 of this effort, a well clear violation was defined if all three of these conditions are true: a) the horizontal clearance is less than 4000 ft., and b) the vertical clearance is less than 450 ft., and c) the time to loss of well clear is less than 35 seconds. This definition was developed with a great deal of community input and testing to ensure interoperability with Air Traffic Control (ATC) and pilots of manned aircraft. Appropriate guidance, alerting and displays were developed to allow UAS, with the appropriate sensors, to effectively maintain well clear. This work contributed to FAA Technical Standard Orders: TSO-C211, Detect and Avoid and TSO-C212, ATAR for Traffic Surveillance. Phase 2 of this work extends the operational environment to include the terminal area and lesser capable aircraft that might not have the payload capability to carry the RADAR defined in Phase 1. This session reports on work from Phase 1 and initial work in Phase 2

Pennsylvania Folklife Vol. 16, No. 1

• Indian Readers and Healers by Prayer • Bayard Taylor\u27s Portrait of Pennsylvania Quakerism • Gypsy Stories from the Swatara Valley • Stump-Pulling • Occult Tales from Union County • Beekeeping and Bee Lore in Pennsylvania • New Materials on the 18th Century Emigration from the Speyer State Archives • The Snake-Bitten Dutchman • Notes and Documents: A Letter to Germany (1806) ; Midwestern Diary of Joel Vale Garretson (1863-1864) • Questionnaire on Hominyhttps://digitalcommons.ursinus.edu/pafolklifemag/1025/thumbnail.jp

The Pentameric Vertex Proteins Are Necessary for the Icosahedral Carboxysome Shell to Function as a CO2 Leakage Barrier

BACKGROUND: Carboxysomes are polyhedral protein microcompartments found in many autotrophic bacteria; they encapsulate the CO(2) fixing enzyme, ribulose-1,5-bisphosphate carboxylase/oxygenase (RubisCO) within a thin protein shell and provide an environment that enhances the catalytic capabilities of the enzyme. Two types of shell protein constituents are common to carboxysomes and related microcompartments of heterotrophic bacteria, and the genes for these proteins are found in a large variety of bacteria. METHODOLOGY/PRINCIPAL FINDINGS: We have created a Halothiobacillus neapolitanus knockout mutant that does not produce the two paralogous CsoS4 proteins thought to occupy the vertices of the icosahedral carboxysomes and related microcompartments. Biochemical and ultrastructural analyses indicated that the mutant predominantly forms carboxysomes of normal appearance, in addition to some elongated microcompartments. Despite their normal shape, purified mutant carboxysomes are functionally impaired, although the activities of the encapsulated enzymes are not negatively affected. CONCLUSIONS/SIGNIFICANCE: In the absence of the CsoS4 proteins the carboxysome shell loses its limited permeability to CO(2) and is no longer able to provide the catalytic advantage RubisCO derives from microcompartmentalization. This study presents direct evidence that the diffusion barrier property of the carboxysome shell contributes significantly to the biological function of the carboxysome

Pennsylvania Folklife Vol. 10, No. 1

• Tramp Work : Penknife Plus Cigar Boxes • Tramps of My Youth • The German Broadside Songs of Pennsylvania • The Rise of Interest in Folk Art • Dutch Treats for Breakfast • The Amish, Citizens of Heaven and America • Collectanea • My Great-Grandmother • Old Sweitzer\u27s Ghost • Pastimes of My Youth • Battalion Day • Seven Days Make One Weekhttps://digitalcommons.ursinus.edu/pafolklifemag/1004/thumbnail.jp