Application of Electrical Resistivity Geophysical Monitoring for Detection of Preferential Flow

Preferential flow is a common occurrence during infiltration yet is often not accounted for in predictive flow models. This has implications for contaminant transport in that the extent of constituent plumes are often underestimated, thereby reducing the effectiveness of any remediation efforts. Electrical resistivity monitoring could be a useful tool to determine if infiltration is bypassing parts of the subsurface through preferential flow pathways and to better inform predictive models. The viability of this method was evaluated through simple electrical simulations and with multiple column experiments across scales using advanced observation techniques like 4D computed tomography. Electrical resistivity was used to monitor the progression of uniform wetting fronts as well as preferential flow and infiltration through macropore networks. Results indicate that certain characteristics in the response of apparent resistivity to preferential flow are distinct from uniform flow. Vertical bulk resistivity reduces rapidly as wetting in a macropore network increases the connectivity between electrodes. Strong positive spikes in electrical anisotropy are observed during preferential flow events and the arrival of a wetting front observed through resistivity monitoring occurs much earlier than predicted using bulk soil properties. These characteristics indicate that electrical resistivity monitoring is a viable method for the application of detecting preferential flow during infiltration in a heterogeneous system

Designing an optometric curriculum

This project will design an optometric curriculum for a theoretical college of optometry. The curriculum will be constructed from a students point of view while conforming to real world limitations

Variability for Traits Used to Estimate Silage Quality in Forage Sorghum Hybrids

The variation among 49 F1 forage sorghum [Sorghum bicolor (L.) Moench.] hybrids from a 7 X 7 cross-classified design was explored in 1979 and 1980 for the following silage traits: dry matter (DM), crude protein, in vitro dry matter disappearance (IVDMD), neutral detergent fiber, acid detergent fiber, acid detergent lignin, ammonia, lactate, and Brix of the juice from fresh stalks. Wider ranges generally were found for male than for female parental means. Means for most traits were significantly different among entries. Significant differences among hybrid means over males and over females were found for only DM, IVDMD, and Brix. Interactions with years existed for most traits. Genetic ratios calculated from the mean squares indicated that general combining ability was important for DM, IVDMD, and Brix. Simple correlation coefficients between traits measured on silage and on fresh-dried samples from the same hybrids were all significant. In view of the effort required to make and evaluate silage samples, initial selection for traits used to estimate quality in fresh-dried samples appears to be the best approach for improving the quality of forage sorghum silage

Variability for Traits Used to Estimate Silage Quality in Forage Sorghum Hybrids

The variation among 49 F1 forage sorghum [Sorghum bicolor (L.) Moench.] hybrids from a 7 X 7 cross-classified design was explored in 1979 and 1980 for the following silage traits: dry matter (DM), crude protein, in vitro dry matter disappearance (IVDMD), neutral detergent fiber, acid detergent fiber, acid detergent lignin, ammonia, lactate, and Brix of the juice from fresh stalks. Wider ranges generally were found for male than for female parental means. Means for most traits were significantly different among entries. Significant differences among hybrid means over males and over females were found for only DM, IVDMD, and Brix. Interactions with years existed for most traits. Genetic ratios calculated from the mean squares indicated that general combining ability was important for DM, IVDMD, and Brix. Simple correlation coefficients between traits measured on silage and on fresh-dried samples from the same hybrids were all significant. In view of the effort required to make and evaluate silage samples, initial selection for traits used to estimate quality in fresh-dried samples appears to be the best approach for improving the quality of forage sorghum silage

In vitro starch disappearance procedure modifications

Four in vitro experiments evaluated the effects of ruminal fluid inoculum:artificial saliva ratios, grinder type, grind size, and diet of ruminal fluid donor on in vitro starch disappearance. Experiment 1 examined rates of starch disappearance and coefficients of determination obtained by linear regression of starch disappearance using five grain sorghum (Sorghum bicolur (L.) Moench) lines, a corn (Zeu muys L.) control, and a wheat (Triticum aestivum L.) control. Grains were incubated for 4, 8, 12, 16, and 20 h with inoculum varying in proportion of ruminal fluid and artificial saliva ( l:l, 1:2, 1:3, and 1:4). In vitro rates of starch disappearance and coefficients of determination were similar for the 1:2, 1:3, and 1:4 inoculum dilutions and were higher (quadratic, P \u3c 0.01) than the 1:1 dilution. As the proportion of artificial saliva in the inoculum increased, in vitro pH increased (linear, P \u3c 0.01). In Experiment 2, six grain sorghum lines and a corn control were ground through a l-mm screen in a Udy (cyclone type) or Wiley mill. Starch disappearance for samples ground using a Udy mill were higher (P 0.10) by grain type fed; however, absolute rates of digestion varied among inoculate sources. Grinder, grind size, and ruminal fluid inoculum:artificial saliva ratios affected rate of starch disappearance in samples digested in vitro. Diet of ruminal fluid donor affected the rate of starch digestion, but not the relative ranking of the grains. If rates are to be compared across in vitro runs for different grains, these processing and dietary factors must be kept constant

Population density modifies the ecological impacts of invasive species

In assessments of ecological impact in invasion ecology, most studies compare un-invaded sites with highly invaded sites, representing the ‘worst-case scenario’, and so there is little information on how impact is modified by the population density of the invader. Here, we assess how ecological impact is modified by population density through the experimental development of density-impact curves for a model invasive fish. Using replicated mesocosms and the highly invasive Pseudorasbora parva as the model, we quantified how their population density influenced their diet composition and their impacts on invertebrate communities and ecosystem processes. The density-impact curves revealed both linear and non-linear density-impact relationships. The relationship between P. parva density and zooplankton body mass was represented by a low-threshold curve, where their impact was higher at low densities than predicted by a linear relationship. In contrast, whilst the relationship between density and zooplankton biomass and abundance was also non-linear, it was high-threshold, indicating a lower impact than a linear relationship would predict. Impacts on diversity and phytoplankton standing stock were linear and impacts on benthic invertebrate abundance and decomposition rates were represented by s-shaped curves. These relationships were underpinned by P. parva dietary analyses that revealed increasing reliance on zooplankton as density increased due to depletion of other resources. We caution against the common assumption that ecological impact increases linearly with invader density and suggest that increased understanding of the relationship between invader population density and ecological impact can avoid under-investment in the management of invaders that cause severe problems at low densities

Barriers to Pediatric Blood Lead Screening

Background: The pernicious effects of lead on the health of children are well-documented. The severity of many of these effects directly correlates with increasing blood lead levels (BLLs). The current recommendation from the Centers for Disease Control and Prevention (CDC) and the American Academy of Pediatrics (AAP) is that BLLs 10 g/dL are dangerous. However, new evidence demonstrates that there is no safe BLL and that children with BLLs /dL exhibit neurological and social deficits. The Vermont Department of Health (VDH) currently recommends universal blood lead screening for 12 and 24 month-old children. In 2006, 79% of 12 month-old children and 41% of 24 month-old children were screened in Vermont.https://scholarworks.uvm.edu/comphp_gallery/1003/thumbnail.jp

A Multi-Code Analysis Toolkit for Astrophysical Simulation Data

The analysis of complex multiphysics astrophysical simulations presents a unique and rapidly growing set of challenges: reproducibility, parallelization, and vast increases in data size and complexity chief among them. In order to meet these challenges, and in order to open up new avenues for collaboration between users of multiple simulation platforms, we present yt (available at http://yt.enzotools.org/), an open source, community-developed astrophysical analysis and visualization toolkit. Analysis and visualization with yt are oriented around physically relevant quantities rather than quantities native to astrophysical simulation codes. While originally designed for handling Enzo's structure adaptive mesh refinement (AMR) data, yt has been extended to work with several different simulation methods and simulation codes including Orion, RAMSES, and FLASH. We report on its methods for reading, handling, and visualizing data, including projections, multivariate volume rendering, multi-dimensional histograms, halo finding, light cone generation and topologically-connected isocontour identification. Furthermore, we discuss the underlying algorithms yt uses for processing and visualizing data, and its mechanisms for parallelization of analysis tasks.Comment: 18 pages, 6 figures, emulateapj format. Resubmitted to Astrophysical Journal Supplement Series with revisions from referee. yt can be found at http://yt.enzotools.org

Short-Term Fire Effects on Small Mammal Populations and Vegetation of the Northern Chihuahuan Desert

Fire is an important ecological factor in semidesert grass-shrub community dynamics, but there is a lack of designed field experiments documenting effects on vegetation and small mammals. We document effects of June prescribed fire on vegetation and small mammals on 20, 25-ha study areas in the Northern Chihuahuan Desert of Southern New Mexico, USA one month and one year posttreatment. Canopy cover of shrubs and grasses recovered to 68 and 27% of the preburn canopy cover, respectively, after one year. Prescribed burns during June enhanced short-term forb production by reducing competition from grasses and shrubs. Thirty thousand trap-nights yielded 1744 captures of 766 individuals of 15 small mammal species. Burns did not affect small mammal species richness and species diversity. Relative abundance of Merriam's kangaroo rats (Dipodomys merriami) was 91% greater on burned sites than on control sites one year postburn. Silky pocket mouse (Perognathus flavus) relative abundance was 221% greater on burned sites one year postburn. Chihuahuan Desert pocket mice (Chaetodipus eremicus) responded negatively to the fire, with relative abundance 170% greater on control sites (=.080). Burning produced short-term benefits for two heteromyids, Merriam's kangaroo rats and silky pocket mice