MODELING SPATIAL DEPENDENCE AND SPATIAL HETEROGENEITY IN COUNTY YIELD FORECASTING MODELS

The implications of ignoring potential spatial dependence in county-level yield data are discussed. Spatial dependence in a county-level yield data set is identified and methods for correcting the dependence via spatial weighting matrices and generalized least squares regression are performed. The paper also examines how the spatial dependence declines as the distance between observations increases.Productivity Analysis, Research Methods/ Statistical Methods,

Intra-Oral Colonization of Macaque Monkeys by Actinobacillus Actinomycetemcomitans

Actinobacillus actinomycetemcomitans was acquired by captive Macaca fascicularis 3 to 6 months after birth, and all monkeys aged over 6 months harbored detectable levels. This microorganism was most frequently isolated from the gingival plaque of the incisor (and other) teeth compared with other oral sites. Strains were leukotoxic by bioassay and Western blot analysis. Antibodies in macaque serum contained neutralized the leukotoxin of a human A. actinomycetemcomitans strain. High titres of maternal neutralizing anti-leukotoxin antibodies were detected in neonates; the titre then fell rapidly so that by 6 months the antibody titer was zero. Antileukotoxin antibody production was detected after 6 months of age, rapidly reaching a high level within 2 years after birth. The presence of leukotoxic strains of A. actinomycetemcomitans in the gingival region did not appear to be correlated with an increase in susceptibility to periodontal disease

Immune Response to Cytolethal Distending Toxin of Aggregatibacter Actinomycetemcomitans in Periodontitis Patients

Background and Objective Cytolethal distending toxin (CDT) is a genotoxin produced by Aggregatibacter actinomycetemcomitans. In spite of its association with pathogenesis, little is known about the humoral immune response against the CDT. This study aimed to test whether subgingival colonization and humoral response to A. actinomycetemcomitans would lead to a response against CDT. Material and Methods Sera from periodontally healthy, localized and generalized aggressive periodontitis and chronic periodontitis subjects (n = 80) were assessed for immunoglobulin G titers to A. actinomycetemcomitans serotypes a/b/c and to each CDT subunit (CdtA, CdtB and CdtC) by ELISA. A. actinomycetemcomitans subgingival levels and neutralization of CDT activity were also analyzed. Results Sera from 75.0% localized and 81.8% generalized aggressive periodontitis patients reacted to A. actinomycetemcomitans. A response to serotype b was detected in localized (66.7%) and generalized aggressive periodontitis (54.5%). Reactivity to A. actinomycetemcomitans correlated with subgingival colonization (R = 0.75, p \u3c 0.05). There was no correlation between A. actinomycetemcomitans colonization or response to serotypes and the immunoglobulin G response to CDT subunits. Titers of immunoglobulin G to CdtA and CdtB did not differ among groups; however, sera of all generalized aggressive periodontitis patients reacted to CdtC. Neutralization of CDT was not correlated with levels of antibodies to CDT subunits. Conclusion Response to CdtA and CdtB did not correlate with the periodontal status of the subject in the context of an A. actinomycetemcomitans infection. However, a response to CdtC was found in sera of generalized but not of localized aggressive periodontitis subjects. Differences in response to CdtC between generalized and localized aggressive periodontitis subjects indicate that CDT could be expressed differently by the infecting strains. Alternatively, the antibody response to CdtC could require the colonization of multiple sites

Quantifying Nonspecific TEM -Lactamase (blaTEM) Genes in a Wastewater Stream

To control the antibiotic resistance epidemic, it is necessary to understand the distribution of genetic material encoding antibiotic resistance in the environment and how anthropogenic inputs, such as wastewater, affect this distribution. Approximately two-thirds of antibiotics administered to humans are β-lactams, for which the predominant bacterial resistance mechanism is hydrolysis by β-lactamases. Of the β-lactamases, the TEM family is of overriding significance with regard to diversity, prevalence, and distribution. This paper describes the design of DNA probes universal for all known TEM β-lactamase genes and the application of a quantitative PCR assay (also known as Taqman) to quantify these genes in environmental samples. The primer set was used to study whether sewage, both treated and untreated, contributes to the spread of these genes in receiving waters. It was found that while modern sewage treatment technologies reduce the concentrations of these antibiotic resistance genes, the ratio of blaTEM genes to 16S rRNA genes increases with treatment, suggesting that bacteria harboring blaTEM are more likely to survive the treatment process. Thus, β-lactamase genes are being introduced into the environment in significantly higher concentrations than occur naturally, creating reservoirs of increased resistance potential.Organismic and Evolutionary Biolog

Prophylaxis after Exposure to Coxiella burnetii

Postexposure prophylaxis may avert Q fever illness and death when the probability of exposure is above the population-specific threshold point

Fungicide baseline for mycelial sensitivity of Exserohilum turcicum, causal agent of northern corn leaf blight

Northern corn leaf blight, caused by Exserohilum turcicum (Et), is one of the major corn diseases which can reduce grain yield and quality. The aim of this study was to determine the mycelial sensitivity of ten Et isolates, five from Argentina and five from Brazil, to six fungicides (carbendazim, captan, fludioxinil, metalaxyl, iprodione and thiram) used in seed treatment. The inhibitory concentration (IC50) was determined by using seven concentrations of the fungicides supplemented to the agar medium. The mycelial colony diameter was measured with a digital caliper. Experimental design was completely randomized with four replicates. Data on the percent mycelial growth inhibition were analyzed by logarithmic regression and the IC50 was calculated. The fungicide iprodione was the most potent, with IC50 50 mg/L for all isolates. Although iprodione is the most potent fungicide, it is not used for corn seed treatment. The IC50s obtained in this study can be used as baseline for future monitoring studies of Et sensitivity to fungicides

Direct estimation of the mutation rate at dinucleotide microsatellite loci in Arabidopsis thaliana (Brassicaceae)

This is the author's accepted manuscript, made available with the permission of the publisher.This research was supported by NIH grant GM073990 and NSF grant DEB-0543052 to J. K. Kelly, NSF grants DEB-9629457 and DEB-9981891 to R. G. Shaw, and NSF DEB-0108242 to M. Orive. M. E. Mort acknowledges DEB-0344883