THE FARM LEVEL EFFECTS OF BETTER ACCESS TO INFORMATION: THE CASE OF DART

In this study, two methods of entering and accessing dairy herd records are compared: the traditional mail-in Dairy Herd Improvement (DHI) system and the Direct Access to Records by Telephone (DART) system, which provides more timely and convenient access to records. An evaluation of DART was carried out using mail survey responses from 117 DART users and telephone surveys of 40 randomly selected users. Results indicate that DART users are generally satisfied with the system and feel that it improves their herd management. Variations in use of the DART system by DART users are explained by herd, cost, and management variables. DART users and comparable non-DART, DHI users are compared with respect to gains in herd production efficiency. Results indicate that DART users made somewhat better gains in most efficiency measures but that the differences were generally not statistically significant.Farm Management,

Structural modeling and functional analysis of the essential ribosomal processing protease Prp from Staphylococcus aureus

In Firmicutes and related bacteria, ribosomal large subunit protein L27 is encoded with a conserved N-terminal extension that is removed to expose residues critical for ribosome function. Bacteria encoding L27 with this N-terminal extension also encode a sequence-specific cysteine protease, Prp, which carries out this cleavage. In this work, we demonstrate that L27 variants with an un-cleavable N-terminal extension, or lacking the extension (pre-cleaved), are unable to complement an L27 deletion in Staphylococcus aureus. This indicates that N-terminal processing of L27 is not only essential but possibly has a regulatory role. Prp represents a new clade of previously uncharacterized cysteine proteases, and the dependence of S. aureus on L27 cleavage by Prp validates the enzyme as a target for potential antibiotic development. To better understand the mechanism of Prp activity, we analyzed Prp enzyme kinetics and substrate preference using a fluorogenic peptide cleavage assay. Molecular modeling and site-directed mutagenesis implicate several residues around the active site in catalysis and substrate binding, and support a structural model in which rearrangement of a flexible loop upon binding of the correct peptide substrate is required for the active site to assume the proper conformation. These findings lay the foundation for the development of antimicrobials that target this novel, essential pathway

RELATIVE SENSITIVITY OF SELECTED DISTRIBUTED LAG ESTIMATORS TO MEASUREMENT AND SPECIFICATION ERROR

Research Methods/ Statistical Methods,

ALTERNATIVE CALIBRATION AND AUCTION INSTITUTIONS FOR PREDICTING CONSUMER WILLINGNESS-TO-PAY FOR NON-GENETICALLY MODIFIED CORN CHIPS

This study explores two important issues in experimental economics: calibration and auction institution. Consumer willingness-to-pay bids for corn chips made with non-genetically modified ingredients are elicited from a 1st price and 2nd price auction. Results suggest that responses to scale differential questions, in a survey, accurately predict consumer willingness-to-pay bids. The 2 nd price auction induces a greater percentage of marginal bidders to offer a positive bid than a 1st price auction. However, average bid levels in the 1st and 2nd price auctions were not statistically different from one other. In a small and unrepresentative sample, 70 percent of student participants were unwilling to pay to exchange a bag of genetically modified corn chips for a bag of non-genetically modified corn chips. However, 20 percent of respondents were willing to pay at least $0.25/oz for the exchange.Consumer/Household Economics, Demand and Price Analysis,

Kinetics and Inhibition Studies of the L205R Mutant of cAMP-Dependent Protein Kinase Involved in Cushing’s Syndrome

Overproduction of cortisol by the hypothalamus–pituitary–adrenal hormone system results in the clinical disorder known as Cushing\u27s syndrome. Genomics studies have identified a key mutation (L205R) in the α‐isoform of the catalytic subunit of cAMP‐dependent protein kinase (PKACα) in adrenal adenomas of patients with adrenocorticotropic hormone‐independent Cushing\u27s syndrome. Here, we conducted kinetics and inhibition studies on the L205R‐PKACα mutant. We have found that the L205R mutation affects the kinetics of both Kemptide and ATP as substrates, decreasing the catalytic efficiency (kcat/KM) for each substrate by 12‐fold and 4.5‐fold, respectively. We have also determined the IC50 and Ki for the peptide substrate‐competitive inhibitor PKI(5–24) and the ATP‐competitive inhibitor H89. The L205R mutation had no effect on the potency of H89, but causes a \u3e 250‐fold loss in potency for PKI(5–24). Collectively, these data provide insights for the development of L205R‐PKACα inhibitors as potential therapeutics

LABOR STRIKES AND THE PRICE OF LETTUCE

This paper examines the economic impact of the 1979 labor strike against lettuce producer-shippers in the Imperial Valley of California. The theory presented suggests that formidable problems are encountered by agricultural labor unions in obtaining higher wages for farm workers. During the 1979 strike, ironically the returns to many of the lettuce producers in the Imperial Valley increased substantially.Demand and Price Analysis, Labor and Human Capital,

Strain gage

A strain gage particularly suited for use in detecting and measuring mechanically induced strain in thermally strained specimens including an elongated link, adapted to be fixedly secured to the surface of a specimen, having thermal expansion characteristics matched with those of the specimen, and characterized by a differential capacitor employed for detecting strain induced motion as such motion is effected between the link and the surface of the specimen

Hydrocarbon photochemistry and Lyman alpha albedo of Jupiter

A combined study of hydrocarbon and atomic hydrogen photochemistry is made to calculate self-consistently the Lɑ albedo of Jupiter. It is shown that the Lɑ emissions observed by Voyagers I and II can be explained by resonance scattering of sunlight. Precipitation-of energetic particles from the magnetosphere can provide the large required source of atomic hydrogen, although the contribution of direct particle excitation to the disk-averaged brightness is insignificant. The variability of the Lɑ brightness inferred from many observations in recent years is examined. The large difference in the brightness of the He 584 Å resonance line observed by Pioneer and Voyager is briefly discussed. Driving the photochemistry by solar ultraviolet radiation alone yields a maximum mixing ratio of C_2H_6 + C_2H_2 at 10^(-2) atm of about 4 x 10^(-6). The possibility of additional CH_4 dissociation from precipitation of magnetospheric particles is discussed. The photochemistry of C_2H_2 and C_2H_3 is sufficiently uncertain not to permit accurate calculations of their densities and the ratio C_2H_6/C_2H_2