Glad Tidings and Grave Warnings: The Role of Advice on Cooperation in Public Goods Dilemmas With Value Uncertainty

We investigate how third-party advice on the estimated value of a public good acts as a dual-uncertainty reducing mechanism to encourage cooperation in a trust social dilemma. Experiment 1 finds that the valence of an advisor’s estimate affects cooperation behavior and that this advice effect is mediated by the level of trust that an individual has in fellow group members. Experiment 2 finds that when estimates about the value of the public good are mixed, trust in experts declines, and trust in other group members also declines. Experiment 3 finds that mixed valence estimates do not affect cooperation behavior when the majority of advisors are in consensus. In merging the social dilemma and advice-giving literatures, we show one way to navigate the dual-uncertainty problem when producing public goods and how independent, third-party advice can influence interpersonal relations among group members

Missile Aerodynamics for Ascent and Re-entry

Aerodynamic force and moment equations are developed for 6-DOF missile simulations of both the ascent phase of flight and a tumbling re-entry. The missile coordinate frame (M frame) and a frame parallel to the M frame were used for formulating the aerodynamic equations. The missile configuration chosen as an example is a cylinder with fixed fins and a nose cone. The equations include both the static aerodynamic coefficients and the aerodynamic damping derivatives. The inclusion of aerodynamic damping is essential for simulating a tumbling re-entry. Appended information provides insight into aerodynamic damping

PERFORMANCE STUDY OF K 2 CsSb PHOTOCATHODE INSIDE A DC HIGH VOLTAGE GUN*

Abstract In the past decade, there has been considerable interest in the generation of tens of mA average current in a photoinjector. Until recently, GaAs:Cs cathodes and K 2 CsSb cathodes have been tested successfully in DC and RF injectors respectively for this application. Our goal is to test the K 2 CsSb photocathode inside a DC gun. Since the multialkali cathode is a compound with constant characteristics over its entire thickness, we anticipate that the lifetime issues seen in GaAs:Cs due to surface damage by ion bombardment would be minimized. Hence successful operation of the K 2 CsSb cathode in a DC gun could lead to a relatively robust electron source capable of delivering ampere level currents. In order to test the performance of a K 2 CsSb cathode in a DC gun, we have designed and built a load lock system that allows the fabrication of the cathode at Brookhaven National Lab (BNL) and its testing at Jefferson Lab (JLab). In this paper, we will present the performance of the K 2 CsSb photocathode in the preparation chamber and in the DC gun

Methodology for Designing Structures to Withstand Extreme Environments: Performance Based Specifications

Existing guidelines in BS 8500 allow the selection of concrete mix based on variables such as compressive strength, maximum water to binder ratio, minimum cement content and minimum cover thickness. This approach does not guarantee the durability and expected performance of the concrete structure in a given environment. One alternative is to develop performance- based specifications that supplement the existing guidelines in BS 8500, by specifying the required performance of concrete in terms of measurable properties such as resistance to environmental penetrations. This paper demonstrates one of such methodology for developing performance-based specifications for concretes exposed to marine environments. Chloride ingress related durability problem being critical in a marine environment, the reliability and repeatability of the different test methods for assessing the rate of chloride ingress is discussed first. Furthermore, a numerical simulation model is used to explore the test data to obtain long-term chloride ingress trends. Based on this, guidelines for selecting appropriate concrete mixes for a marine exposure is presented and discussed

ELISA-Based Measurement of Antibody Responses and PCR-Based Detection Profiles Can Distinguish between Active Infection and Early Clearance of Borrelia burgdorferi

Borrelia burgdorferi is a spirochetal bacterium that causes Lyme disease. These studies address whether current research methods using either ELISA to detect seroconversion to B. burgdorferi antigens or PCR quantification of bacterial DNA within tissues can accurately distinguish between a productive infection versus a B. burgdorferi exposure that is rapidly cleared by the innate responses. Mice receiving even minimal doses of live B. burgdorferi produced significantly more B. burgdorferi-specific IgM and IgG than groups receiving large inocula of heat-killed bacteria. Additionally, sera from mice injected with varied doses of killed B. burgdorferi recognized unique borrelial antigens compared to mice infected with live B. burgdorferi. Intradermal injection of killed B. burgdorferi resulted in rapid DNA clearance from skin, whereas DNA was consistently detected in skin inoculated with viable B. burgdorferi. These data indicate that both ELISA-based serological analyses and PCR-based methods of assessing B. burgdorferi infection clearly distinguish between an established infection with live bacteria and exposure to large numbers of bacteria that are promptly cleared by the innate responses

SPECIFICATIONS OF A PROTOTYPE SOFTWARE SYSTEM FOR DEVELOPING VARIABLE-RATE TREATMENT PRESCRIPTIONS FOR USE IN PRECISION AGRICULTURE

This paper discusses the process of developing variable-rate treatment prescriptions and gives specifications for a prototype software system for implementing that process. The process is based on statistical analysis of data from embedded field trials, and incorporates producer preferences in determining a treatment prescription. The system can be used by researchers in agricultural research stations for developing prescriptions for commercial agricultural producers. The specifications provided are general enough to be implemented using a variety of statistical and database packages that are available to researchers. In addition to these specifications we provide online access to source code for implementing the system in SAS. We use this system to develop treatment prescriptions for a commercial cotton farming operation in northeast Louisiana. The prescriptions are based on data from a precision agriculture experiment conducted in 2006. The objective of that study was to compare the effects of five nitrogen rates on cotton lint yield across several soil types for the purpose of developing a variable-rate nitrogen treatment prescription for future use on that farm. Several possible producer preferences were incorporated with the results of the field trial to produce optional treatment prescriptions for the producer

Horizontally transferred genes in plant-parasitic nematodes: a high-throughput genomic approach

BACKGROUND: Published accounts of horizontally acquired genes in plant-parasitic nematodes have not been the result of a specific search for gene transfer per se, but rather have emerged from characterization of individual genes. We present a method for a high-throughput genome screen for horizontally acquired genes, illustrated using expressed sequence tag (EST) data from three species of root-knot nematode, Meloidogyne species. RESULTS: Our approach identified the previously postulated horizontally transferred genes and revealed six new candidates. Screening was partially dependent on sequence quality, with more candidates identified from clustered sequences than from raw EST data. Computational and experimental methods verified the horizontal gene transfer candidates as bona fide nematode genes. Phylogenetic analysis implicated rhizobial ancestors as donors of horizontally acquired genes in Meloidogyne. CONCLUSIONS: High-throughput genomic screening is an effective way to identify horizontal gene transfer candidates. Transferred genes that have undergone amelioration of nucleotide composition and codon bias have been identified using this approach. Analysis of these horizontally transferred gene candidates suggests a link between horizontally transferred genes in Meloidogyne and parasitism