George C.J. Fernandez

Fine root growth dynamics of four Mojave Desert shrubs as related to soil moisture and microsite

Water is generally considered to be the major limiting factor for perennial shrub growth in the Mojave Desert, USA. However, the responses of active fine roots to soil moisture and microsite differed among Ambrosia dumosa, Ephedra nevadensis, Larrea tridentata, and Lycium pallidum, suggesting differences in root foraging strategies. Ambrosia and Ephedra had a positive linear relationship between active fine root lengths and soil moisture and more roots under the canopy, whereas Larrea had a negative linear relationship and more roots in the interspace. Lycium did not show a significant root/water relationship or significant differences between canopy and interspace microsites.

Statistical Data Mining Using SAS Applications, Second Edition

Statistical Data Mining Using SAS Applications, Second Edition describes statistical data mining concepts and demonstrates the features of user-friendly data mining SAS tools. Integrating the statistical and graphical analysis tools available in SAS systems, the book provides complete statistical data mining solutions without writing SAS program codes or using the point-and-click approach. Each chapter emphasizes step-by-step instructions for using SAS macros and interpreting the results. Compiled data mining SAS macro files are available for download on the authors website. By following the step-by-step instructions and downloading the SAS macros, analysts can perform complete data mining analysis fast and effectively. New to the Second EditionGeneral Features Access to SAS macros directly from desktop Compatible with SAS version 9, SAS Enterprise Guide, and SAS Learning Edition Reorganization of all help files to an appendix Ability to create publication quality graphics Macro-call error check New Features in These SAS-Specific Macro Applications Converting PC data files to SAS data (EXLSAS2 macro) Randomly splitting data (RANSPLIT2) Frequency analysis (FREQ2) Univariate analysis (UNIVAR2) PCA and factor analysis (FACTOR2) Multiple linear regressions (REGDIAG2) Logistic regression (LOGIST2) CHAID analysis (CHAID2) Requiring no experience with SAS programming, this resource supplies instructions and tools for quickly performing exploratory statistical methods, regression analysis, logistic regression multivariate methods, and classification analysis. It presents an accessible, SAS macro-oriented approach while offering comprehensive data mining solutions.

Selection, evaluation, and identification of improved Russet Norkotah strains

Strain (sub-clonal, line, or intraclonal) selection for certain characteristics within some potato varieties has been very successful e.g. improved skin type (Russet Burbank from Burbank), improved skin color (Red LaSoda from LaSoda; Red Norland and Dark Red Norland from Norland), and improved vine vigor and yield (Norgold Russet M from Norgold Russet). In 1989, strain selection with Russet Norkotah was initiated by the Texas Potato Variety Development Program. Some 192 giant hill and/or tall type plants were selected from seedsmen and/or commercial Russet Norkotah fields in Colorado, while 183 were selected from commercial fields in Texas. Replicated yield trials with the final 13 of the original strain selections and Russet Norkotah were conducted in 1992, 1993, and 1994 in both Colorado and Texas. A mixed model analysis of variance was performed followed by disjoint cluster analysis in order to group strains into high, medium, and low yielding classes or clusters. Canonical discriminant analysis was performed to confirm the three clusters and to determine the extent to which various yield attributes are related and can be used to separate the three clusters. Several strains including TXNS (Texas Norkotah Strain) 112, TXNS 134, and TXNS 278 were identified as superior in Colorado, while TXNS 223, TXNS 249, and TXNS 296 were similarly identified for Texas growing conditions. These strains usually outyielded Russet Norkotah by 20–30%.

Influence of pH treatments on survival of Escherichia coli O157:H7 in continuous cultures of rumen contents.

The pH (i.e., 5.5, 5.75, 6.0, 6.25, 6.5, 6.75, 7.0, and 7.25) effect on Escherichia coli O157:H7 in an artificial rumen model was investigated. Eight fermenters were inoculated with bovine rumen fluid and were supplied with a diet (75 g of dry matter daily in 12 equal portions [every 2 hr]) containing similar forage-to-concentrate ratio. After an adaptation period (i.e., 3 days for adjusting the rumen fluid [pH 6.2] microbial population to the test pH and 4 days for adjustment to the diet at the test pH), each fermenter was inoculated with 109 cells of E. coli O157:H7. Samples were collected hourly for 12 hr and every 2 hr for an additional 12 hr and were analyzed by flow cytometer. E. coli O157:H7 could not be quantified after 24 hr, and detection was only possible after enrichment. Because the pathogen could not be detected 5 days postinoculation (i.e., Day 13), the fermenters were reinoculated with E. coli O157:H7 on Days 17 and 22. E. coli O157:H7 numbers decreased from 106 to 104/ml of fermenter contents in a quadratic (P < 0.05) fashion over the 24-hr sampling period, and the rate of reduction was slower (P < 0.05) for pH 7.0 than for other pH treatments. Results suggested that E. coli O157:H7 population were decreased by competitive exclusion and were not affected by culture pH.

Norgold Russet and Norgold Russet strain M — additional evidence for genetic dissimilarity

Potato improvement through strain selection has been under-exploited and sometimes discredited by plant breeders, even though successes, such as Russet Burbank, have been recognized. For years, seedsmen have rogued out “off-types” in order to maintain varietal purity. It is suggested that these off-types can sometimes offer an opportunity for developing improved strains or, depending on definition, improved varieties similar to the original variety, but possessing one or more unique characters which render it more acceptable or better adapted than the original variety. In Texas, Norgold Russet strain M, a selection out of Norgold Russet, is such an example. In this investigation, 2 genotypes, Norgold Russet and Norgold Russet strain M, were analyzed based on yield and plant attributes from 2 Texas sites over an 11-year period. Significant genotype x site, genotype x year, and genotype x site x year interactions were found, supporting the hypothesis that these 2 potato genotypes are phenotypically and presumably genetically dissimilar. Canonical discriminant analysis, using yield and plant attributes, confirmed these findings and provides additional evidence that varietal strains might deserve designation as unique varieties.CompendioEl mejoramiento genético de la papa mediante selectión de clones ha sido subestimado y algunas veces desacreditado por los fitomejoradores, a pesar de que algunas variedades han sido desarrolladas mediante éste método de selección, como es el caso de Russet Burbank. Por muchos años, los productores de semilla han ido eliminando plantas fuera de tipo como una manera de mantener la pureza varietal. Estas plantas fuera de tipo han sido usadas como base para el desarrollo de clones o variedades mejoradas similares a la variedad original, pero con una o más características includas que la hacen más aceptable o mejor adaptada que la variedad original. Un ejemplo es el clon Norgold Russet strain M, el cual ha sido seleccionado de la variedad Norgold Russet en Texas. En la présente investigación los genotipos Norgold Russet y Norgold Russet strain M, fueron evaluados en base a su rendimiento y caractersticas agronómicas en 2 localidades de Texas durante un periodo de 11 años. El análisis de los resultados indicó que las interacciones genotipo x localidad, genotipo x ano y genotipo x localidad x año fueron significativas, lo cual representa evidencia a favor de la hipótesis de que los 2 genotipos de papa son diferentes en fenotipo y genotipo. El análisis canónico discriminante del rendimiento y caractersticas agronómicas confirm’p estos resultados dando evidencia adicional de que los clones varietales pueden ser designados como variedades.

Hungry Mondays: Low-Income Children in Childcare

ABSTRACT The Child and Adult Care Food Program (CACFP) plays a critical role by providing food to children from low-income families while they are enrolled in licensed childcare or attending approved after-school programs. There is little documentation about how many childcare centers with eligible children receive CACFP funding or whether participating children come into those centers hungry or how centers handle these situations. Findings from 2 studies reveal that there are children who enter childcare centers displaying hunger, particularly after a school break. Thoughtful strategies and policies for coping with this situation should be considered.

Plant establishment on angle of repose mine waste dumps.

Angle of repose slopes associated with mine waste dumps are difficult to revegetate due to steep slope angle, poor soil proper ties, and potential for extensive soil erosion. We examined the extent that seed movement, seedling establishment, soil characteristics, nutrient availability, and water availability were responsible for limiting plant establishment or survival on steep (average slope ~80%), south-facing angle of repose slopes at a gold mine north of Elko, Nev. Four treatments were established: 1) unaltered mine waste soil; 2) mine waste soil with fertilizer; 3) mine waste soil draped with at least 0.3 m of a fine-textured cov ersoil; and 4) treatments 2 and 3 combined. All treatments had study plots that received either broadcast seeds or containerized transplants. Seedlings from broadcast seeds only emerged on plots that were coversoiled, but transplants survived in all treat ments. Thus, coversoiling was necessary at this site for seedling germination and establishment, but survival of transplants in unaltered mine waste soil indicated that nutrient availability, soil-root contact, and water availability were sufficient for plant survival. In addition, long distance transport of seeds down sta ble, angle of repose slopes was not detected during the first grow ing season after seeding, indicating that the lack of seedlings on angle of repose slopes was not due to movement of seeds down slope. However, coversoiling resulted in unstable slope surfaces; both erosion and soil mass wastage were observed on coversoiled treatments. Thus, although coversoiling increased establishment and survival of plants on angle of repose slopes, slope stabiliza tion is necessary to ensure the success of revegetation efforts and to prevent the coversoil from eroding and moving downslope.

Determination of the Potential for Release of Mercury from Combustion Product Amended Soils: Part 1—Simulations of Beneficial Use

Abstract This paper describes a project that assessed the potential for mercury (Hg) release to air and water from soil amended with combustion products to simulate beneficial use. Combustion products (ash) derived from wood, sewage sludge, subbituminous coal, and a subbituminous coal-petroleum coke mixture were added to soil as agricultural supplements, soil stabilizers, and to develop lowpermeability surfaces. Hg release was measured from the latter when intact and after it was broken up and mixed into the soil. Air-substrate Hg exchange was measured for all materials six times over 24 hr, providing data that reflected winter, spring, summer, and fall meteorological conditions. Dry deposition of atmospheric Hg and emission of Hg to the atmosphere were both found to be important fluxes. Measured differences in seasonal and diel (24 hr) fluxes demonstrated that to establish an annual estimate of air-substrate flux from these materials data on both of these time steps should be collected. Air-substrate exchange was highly correlated with soil and air temperature, as well as incident light. Hg releases to the atmosphere from coal and wood combustion product-amended soils to simulate an agricultural application were similar to that measured for the unamended soil, whereas releases to the air for the sludge-amended materials were higher. Hg released to soil solutions during the Synthetic Precipitation Leaching Procedure for ash-amended materials was higher than that released from soil alone. On the basis of estimates of annual releases of Hg to the air from the materials used, emissions from coal and wood ash-amended soil to simulate an agricultural application could simply be re-emission of Hg deposited by wet processes from the atmosphere; however, releases from sludge-amended materials and those generated to simulate soil stabilization and disturbed low-permeability pads include Hg indigenous to the material.

Determination of the Potential for Release of Mercury from Combustion Product Amended Soils: Part 2—Coal Fly Ash Generated Stabilized Soil and Degradation Products

Abstract The potential for mercury (Hg) releases to the air and water from three soils, two subbituminous coal fly ashes, and mixtures of these materials as stabilized soil was assessed. In addition, the potential for Hg release from crushed stabilized material mixed into soil simulating degradation over time was investigated. In general, atmospheric Hg deposition was measured for the ash and materials made using the ash with the higher Hg concentration (ash 1, 0.25 μg · g−1), whereas the second ash material (ash 2; ∼0.08 μg · g−1) and materials generated using this ash exhibited emission as the dominant flux. Fluxes measured from stabilized material were less than that measured for the pure ash material but of the same direction. Although the stabilized and degraded stabilized materials exhibited Hg fluxes that were significantly different from base soils, values were within the range reported for low Hg-containing background soils. Because of limitations of the experimental design (i.e., reduced light exposures and measurement of flux from dry materials) reported fluxes are most likely underestimates of that which would occur in the natural environment. Materials made to simulate degradation of the stabilized material did not exhibit higher releases than the stabilized material alone. Synthetic Precipitation Leaching Procedure (SPLP; EPA method 1312) results showed that the chemistry of a soil, especially pH, may influence the amount of Hg released to soil solutions, with more acidic soils potentially enhancing Hg release.