Patterns of water uptake and rhizosphere salinity in Casuarina Obesa Miq. during a drying period at Lake Toolibin, Western Australia

Lake Toolibin is one of a few remaining freshwater lakes in the central wheatbelt of Western Australia. Since monitoring began at Lake Toolibin in the early 1970\u27s groundwater levels have risen to within 1-2 m of the lakebed with an accompanying migration of salt. The site-specific nature of water uptake in Casuarina obesa Miq. (the dominant lakebed tree species) and rhizosphere salinity were explored spatially through analyses of soil properties (groundwater depth and salinity, particle size and components of soil water potential ψ1). Plant water sources (using δ2H signatures) and water availability (based on ψleaf and ψt) were measured to define water uptake within the rhizosphere. Plant response to these conditions was determined using critical indicators of plant water relations such as stomatal conductance (gs) and water use. This investigation was conducted over a drying period (October 2002 - February 2003) on the lakebed. The drying period coincided with a maximum in soil water potential (ψ1) and sites with shallower depths to groundwater had soil profiles dominated by osmotic potentials (ψ0) due to the accumulation of salts near the soil surface. At some sites groundwater was transmitted above the water table along films of coarse textured sands, forming perched systems of thin saturated soil (0.l - 0.2 m). These were important mechanisms in the transport of saline groundwater to the rhizosphere. Patterns of water uptake for C. obesa across the lake appeared to be closely related to seasonal effects of the drying period and soil water and salt movement from the capillary fringe. Pre-dawn leaf water potentials (ψpd), stomatal conductance and water use decreased during summer at all sites, especially where salt accumulation had occurred, but this species exhibited substantial tolerance to moisture deficits caused by salt accumulation. C. obesa obtains its summer moisture from relatively shallow depths (\u3c 0.9 m) and regulates water loss through stomatal control during this period, allowing it to persist under these conditions

Psychosocial, Socioeconomic, Behavioral, and Environmental Risk Factors for BMI and Overweight Among 9-to-11-Year Old Children

This study explored the risk factors for higher BMI and overweight in 9- to 11-year-old children using the 2007 California Children’s Healthy Eating and Exercise Practices Survey. A total of 741 children completed a two-day food and activity diary. Of these, 299 children participated in the follow-up telephone interview, reporting attitudes and beliefs. Linear regressions identified risk factors related to BMI z-scores; logistic regressions were used for binomial overweight status. Independent variables included children’s diet, activity, screen time, food modeling, family norms/rules, home environment, poverty, and parent education, adjusting for race/ethnicity. Parent education was the strongest risk factor with a clear gradient towards reduced risk as parent education improved. Children were .3 BMI z points lower and one-third less likely to be overweight as education level rose. Each serving of fried vegetables consumed was related to .3 point increase in BMI z. Children were 1.2-1.3 times more likely to be overweight with each increase in school lunch participation. Low-cost overweight prevention efforts targeting children with less parent education, school lunches, and consumption of fried vegetables may reduce BMI and help prevent childhood overweight. Additional investigation should determine the underlying factors contributing to the relationship between eating school lunch and overweight

Assessment of Microbiologically Influenced Corrosion Potential in the International Space Station Internal Active Thermal Control System Heat Exchanger Materials: A 6-Momths Study

The fluid in the Internal Active Thermal Control System (IATCS) of the International Space Station (ISS) is water based. The fluid in the ISS Laboratory Module and Node 1 initially contained a mix of water, phosphate (corrosion control), borate (pH buffer), and silver sulfate (Ag2SO4) (microbial control) at a pH of 9.5+/-0.5. Over time, the chemistry of the fluid changed. Fluid changes included a pH drop from 9.5 to 8.3 due to diffusion of carbon dioxide (CO2) through Teflon(reistered Trademark) (DuPont) hoses, increases in dissolved nickel (Ni) levels, deposition of silver (Ag) to metal surfaces, and precipitation of the phosphate (PO4) as nickel phosphate (NiPO4). The drop in pH and unavailability of a antimicrobial has provided an environment conducive to microbial growth. Microbial levels in the fluid have increased from >10 colony-forming units (CFUs)/100 ml to 10(exp 6) CFUs/100 ml. The heat exchangers in the IATCS loops are considered the weakest point in the loop because of the material thickness (=7 mil). It is made of a Ni-based braze filler/CRES 347. Results of a preliminary test performed at Hamilton Sundstrand indicated the possibility of pitting on this material at locations where Ag deposits were found. Later, tests have confirmed that chemical corrosion of the materials is a concern for this system. Accumulation of micro-organisms on surfaces (biofilm) can also result in material degradation and can amplify the damage caused by the chemical corrosion, known as microbiologically influenced corrosion (MIC). This paper will discuss the results of a 6-mo test performed to characterize and quantify the damage from microbial accumulation on the surface of the ISS/ATCS heat exchanger materials. The test was designed to quantify the damage to the materials under worst-case conditions with and without micro-organisms present at pH 8.3 and 9.5

Insect resistance of a full sib family of tetraploid switchgrass \u3ci\u3ePanicum virgatum\u3c/i\u3e L. with varying lignin levels

Little information is available on insect resistance mechanisms and inheritance in biomass grasses. Although reduction of lignin in biomass grasses in order to increase the efficiency of fermentation may result in increased susceptibility to insect feeding, other resistance mechanisms may be more important. Field grown leaves of two tetraploid parent (Kanlow N1, Summer) and 14 progeny switchgrass (Panicum virgatum L.) plant clones selected for a diversity of plant form and ranges in lignin levels were tested for leaf resistance to feeding by the fall armyworm (Spodoptera frugiperda J. E. Smith), a grass feeding insect pest. Although lignin generally appeared important as a resistance mechanism only at early season stages, replicate clones of two low lignin progeny plants generally remained resistant to fall armyworm feeding. Mechanical damaging increased resistance to fall armyworm feeding in several of these plants. Degrees of resistance were sometimes associated with leaf form of progeny. These results indicate there are likely multiple insect resistance mechanisms operating at different stages in switchgrass, and that segregation of some mechanisms appears related to growth form of the plants

Game story space of professional sports: Australian rules football

Sports are spontaneous generators of stories. Through skill and chance, the script of each game is dynamically written in real time by players acting out possible trajectories allowed by a sport\u27s rules. By properly characterizing a given sport\u27s ecology of game stories, we are able to capture the sport\u27s capacity for unfolding interesting narratives, in part by contrasting them with random walks. Here we explore the game story space afforded by a data set of 1310 Australian Football League (AFL) score lines. We find that AFL games exhibit a continuous spectrum of stories rather than distinct clusters. We show how coarse graining reveals identifiable motifs ranging from last-minute comeback wins to one-sided blowouts. Through an extensive comparison with biased random walks, we show that real AFL games deliver a broader array of motifs than null models, and we provide consequent insights into the narrative appeal of real games

The effects of fire and tephra deposition on forest vegetation in the Central Cascades, Oregon

High-resolution charcoal and pollen analyses were used to reconstruct a 12,000-yr-long fire and vegetation history of the Tumalo Lake watershed and to examine the short-term effects that tephra deposition have on forest composition and fire regime. The record suggests that, from 12,000 to 9200 cal yr BP, the watershed was dominated by an open Pinus forest with Artemisia as a common understory species. Fire episodes occurred on average every 115 yr. Beginning around 9200 cal yr BP, and continuing to the present, Abies became more common while Artemisia declined, suggesting the development of a closed forest structure and a decrease in the frequency of fire episodes, occurring on average every 160 yr. High-resolution pollen analyses before and after the emplacement of three distinct tephra deposits in the watershed suggest that nonarboreal species were most affected by tephra events and that recovery of the vegetation community to previous conditions took between 40 and 100 yr. Changes in forest composition were not associated with tephra depositional events or changes in fire-episode frequency, implying that the regional climate is the more important control on long-term forest composition and structure of the vegetation in the Cascade Range