PLANTING DECISIONS AND UNCERTAIN CONSUMER ACCEPTANCE OF GENETICALLY MODIFIED CROP VARIETIES

There exists much uncertainty about consumer attitudes towards genetically modified foods. If it happens that sufficient (insufficient) acres are planted under non-modified seed to meet post-harvest demand, then a price premium will not (will) emerge for the non-modified varieties. A non-linearity originates in the fact that a price premium may be supported. This non-linearity interacts with the extent of demand uncertainty to determine equilibrium varietal plantings and the probability that post-harvest varietal prices will differ. Also, as planting approaches signals will be received by growers about the nature of demand they will be planting into. We show how the non-linearity affects the order on the types of signals that risk-neutral growers will prefer to receive.Consumer/Household Economics, Crop Production/Industries,

LOCATION, LAND QUALITY, AND RENTAL VOLATILITY

It appears to be widely believed that returns on low quality land are more variable than on high quality land. Using Ricardian rent as the measure of returns and sensitivity to output price as the measure of volatility, we investigate this null hypothesis for three different measures of quality. These are proximity to market, output productivity, and cost efficiency. In all cases, we identify precise conditions on the production technology such that rental volatility varies in a monotone manner with land quality. A method of econometric investigation of the relationship between rental volatility and land quality is developed and applied to Iowa cash rents data collected during 1994-2000. Our preliminary findings provide partial empirical support for the null hypothesis of an inverse relationship between quality and rental volatility with respect to commodity prices.Land Economics/Use,

State-Contingent Demand for Herbicide-Tolerance Seed Trait

Suppose a farmer had to apply a herbicide pre-emergence or not at all. The advent of a herbicide-tolerance trait innovation then provides the option to wait for more information before making a state-contingent post-emergence application. This option to wait can increase or decrease average herbicide use. For heterogeneous acre types, trait royalties increase with the level of uncertainty about the extent of weed damage. Royalties are largest when acre infestation susceptibility types are bunched around the type indifferent to applying the herbicide in the absence of the trait. The trait complements (substitutes for) information technologies that facilitate informed post-emergence (pre-emergence) decisions.

Performance of the Mortality in emergency department Sepsis score for predicting hospital mortality among patients with severe sepsis and septic shock

Objective The aim of the study was to test if the Mortality in Emergency Department Sepsis (MEDS) score accurately predicts death among emergency department (ED) patients with severe sepsis and septic shock. Methods This study was a preplanned secondary analysis of a before-and-after interventional study conducted at a large urban ED. Inclusion criteria were suspected infection, 2 or more criteria for systemic inflammation, and either systolic blood pressure of less than 90 mm Hg after a fluid bolus or lactate 4 mmol/L or higher. Exclusion criteria were: age of less than 18 years, no aggressive care desired, or need for immediate surgery. Clinical and outcomes data were prospectively collected on consecutive eligible patients for 1 year before and 1 year after implementing early goal-directed therapy (EGDT). The MEDS scores and probabilities of in-hospital death were calculated. The main outcome was in-hospital mortality. The area under the receiver operating characteristic curve was used to evaluate score performance. Results One hundred forty-three patients, 79 pre-EGDT and 64 post-EGDT, were included. The mean age was 58 ± 17 years, and pneumonia was the source of infection in 37%. The in-hospital mortality rate was 23%. The area under the receiver operating characteristic curve for MEDS to predict mortality was 0.61 (95% confidence interval [CI], 0.50-0.72) overall, 0.69 (95% CI, 0.56-0.82) in pre-EGDT patients, and 0.53 (95% CI, 0.33-0.74) in post-EGDT patients. Conclusions The MEDS score performed with poor accuracy for predicting mortality in ED patients with sepsis. These results suggest the need for further validation of the MEDS score before widespread clinical use

The Self-Identity Protein IdsD Is Communicated between Cells in Swarming Proteus mirabilis Colonies

Proteus mirabilis is a social bacterium that is capable of self (kin) versus nonself recognition. Swarming colonies of this bacterium expand outward on surfaces to centimeter-scale distances due to the collective motility of individual cells. Colonies of genetically distinct populations remain separate, while those of identical populations merge. Ids proteins are essential for this recognition behavior. Two of these proteins, IdsD and IdsE, encode identity information for each strain. These two proteins bind in vitro in an allele-restrictive manner. IdsD-IdsE binding is correlated with the merging of populations, whereas a lack of binding is correlated with the separation of populations. Key questions remained about the in vivo interactions of IdsD and IdsE, specifically, whether IdsD and IdsE bind within single cells or whether IdsD-IdsE interactions occur across neighboring cells and, if so, which of the two proteins is exchanged. Here we demonstrate that IdsD must originate from another cell to communicate identity and that this nonresident IdsD interacts with IdsE resident in the recipient cell. Furthermore, we show that unbound IdsD in recipient cells does not cause cell death and instead appears to contribute to a restriction in the expansion radius of the swarming colony. We conclude that P. mirabilis communicates IdsD between neighboring cells for nonlethal kin recognition, which suggests that the Ids proteins constitute a type of cell-cell communication.Molecular and Cellular Biolog

Two Proteins Form a Heteromeric Bacterial Self-Recognition Complex in Which Variable Subdomains Determine Allele-Restricted Binding

ABSTRACT Self- versus nonself-recognition in bacteria has been described recently through genetic analyses in multiple systems; however, understanding of the biochemical properties and mechanisms of recognition-determinant proteins remains limited. Here we extend the molecular and biochemical understanding of two recognition-determinant proteins in bacteria. We have found that a heterotypic complex is formed between two bacterial self-recognition proteins, IdsD and IdsE, the genes of which have been shown to genetically encode the determinants for strain-specific identity in the opportunistic bacterial pathogen Proteus mirabilis. This IdsD-IdsE complex forms independently of other P. mirabilis-encoded self-recognition proteins. We have also shown that the binding between IdsD and IdsE is strain- and allele-specific. The specificity for interactions is encoded within a predicted membrane-spanning subdomain within each protein that contains stretches of unique amino acids in each P. mirabilis variant. Finally, we have demonstrated that this in vitro IdsD-IdsE binding interaction correlates to in vivo population identity, suggesting that the binding interactions between IdsD and IdsE are part of a cellular pathway that underpins self-recognition behavior in P. mirabilis and drives bacterial population sociality