18 research outputs found
Using Remote Sensing Mapping and Growth Response to Environmental Variability to Aide Aquatic Invasive Plant Management
Management of aquatic weeds in complex watersheds and river systems present many challenges to assessment, planning and implementation of management practices for floating and submerged aquatic invasive plants. The Delta Region Areawide Aquatic Weed Project (DRAAWP), a USDA sponsored area-wide project, is working to enhance planning, decision-making and operational efficiency in the California Sacramento-San Joaquin Delta. Satellite and airborne remote sensing are used map (area coverage and biomass density), direct operations, and assess management impacts on plant communities. Archived satellite records enable review of results following previous climate and management events and aide in developing long-term strategies. Examples of remote sensing aiding effectiveness of aquatic weed management will be discussed as well as areas for potential technological improvement. Modeling at local and watershed scales using the SWAT modeling tool provides insight into land-use effects on water quality (described by Zhang in same Symposium). Controlled environment growth studies have been conducted to quantify the growth response of invasive aquatic plants to water quality and other environmental factors. Environmental variability occurs across a range of time scales from long-term climate and seasonal trends to short-term water flow mediated variations. Response time for invasive species response are examined at time scales of weeks, day, and hours using a combination of study duration and growth assessment techniques to assess water quality, temperature (air and water), nitrogen, phosphorus, and light effects. These provide response parameters for plant growth models in response to the variation and interact with management and economic models associated with aquatic weed management. Plant growth models are to be informed by remote sensing and applied spatially across the Delta to balance location and type of aquatic plant, growth response to altered environments and phenology. Initial utilization of remote sensing tools developed for mapping of aquatic invasive plants improved operational efficiency in management practices. These assessment methods provide a comprehensive and quantitative view of aquatic invasive plants communities in the California Delta
Effects of Disinfectants in Water on Mir- and Earth-Grown Wheat
Iodine and silver fluoride are used to purify water onboard U. S. Shuttles and the Russian Space Station, Mir, respectively. In 1995, iodine-treated water, which ranged from 1.0-4.0 mg x kg(exp -1) with a mean of 2.9 mg x kg(exp -1), was applied to Super Dwarf wheat (Triticum aestivum L.) plants when Mir water (grey or tech grade) became scarce. The potential phytotoxicity of iodine on Super Dwarf wheat is an unknown. Since use of iodine-treated water was not part of the experiment, we sought to determine whether it accounted for the subsequent poor wheat seedling growth and floral development onboard the Mir. Super Dwarf wheat seeds were imbibed in iodine or silver fluoride concentrations of 0.0, 1.0, 2.0, 4.0, 8.0 or 16.0 mg x kg(exp -1) for 96 h at 4 C. Five seeds were then planted per 13.3 cm x 13.3 cm pots containing a granular clinoptilolite (Cp) zeolite (1 -2 mm dia.) and placed in Percival(TM) growth chambers programmed for 20/15 C and 18/6 h d/n regime. Plants were irrigated with distilled water, and Iodine- or silver fluoride-treated distilled water. In separate experiments, seeds were treated as above and germination and early seedling growth were determined by examining seedling responses to disinfectants in rolled paper towels. Silver fluoride had very little effect on wheat seed germination. By contrast, iodine reduced germination at all treatment levels. Seedlings exposed to 1.0, 2.0, and 4.0 mg x kg(exp -1) of iodine or silver fluoride levels exhibited a slight stimulation in shoot and root growth. Both disinfectants at 8 and 16 mg x kg(exp -1) showed significantly (p is less than or equal to 0.01) reduced seedling shoot and root lengths and fresh biomasses compared to the control and lower disinfectant levels. The number of spikelets per spike, florets per spikelet, seeds per spike and seed weight were also significantly reduced at the 8 and 16 mg x kg(exp -1) compared to the control and lower levels of disinfectant. Based on these ground-based post-flight analyses, the levels of iodine- and/or silver fluoride-treated water used on Mir-grown plants onboard the Mir did not cause the poor growth and development of the wheat plants
Plant Growth During the Greenhouse II Experiment on the MIR Orbital Station
We carried out three experiments with Super Dwarf wheat in the Bulgarian/Russian growth chamber Svet (0.1 sq m growing area) on the Space Station Mir. This paper mostly describes the first of these NASA-supported trials, began on Aug. 13, 1995. Plants were sampled five times and harvested on Nov. 9 after 90 days. Equipment failures led to low irradiance (three, then four of six lamp sets failed), instances of high temperatures (ca. 37 C), and sometimes excessive-substrate moisture. Although plants grew for the 90 days, no wheat heads were produced. Considering the low light levels, plants were surprisingly green, but of course biomass production was low. Plants were highly disoriented (low light, mirror walls?). Fixed and dried samples and the root module were returned on the US Shuttle Atlantis on Nov. 20, 1995. Samples of the substrate, a nutrient-charged zeolite called Balkanine, were taken from the root module, carefully examined for roots, weighed, dried, and reweighed. The Svet control unit and the light bank were shipped to Moscow. An experiment validation test (EVT) of plant growth and experiment procedures, carried out in Moscow, was highly successful. Equipment built in Utah to measure CO2, H2O vapor, irradiance, air and leaf (IR) temperature, O2, pressure, and substrate moisture worked well in the EVT and in space. After this manuscript was first prepared, plants were grown in Mir with a new light bank and controller for 123 days in late 1996 and 39 days in 1996/1997. Plants grew exceptionally well with higher biomass production than in any previous space experiment, but the ca. 280 wheat heads that were produced in 1996 contained no seeds. Ethylene in the cabin atmosphere was responsible
Inner liner temperature variation caused deformation localisation effects in a multichannel model of a generic LRE wall structure
The inner liner of a regeneratively cooled wall of a main stage rocket combustion chamber is extremely loaded by the high temperature of the hot gas and the pressure
difference between the coolant and the hot gas. A cyclic operation of such a chamber usually causes a LFC failure of the wall structure after a very low number of cycles. The
development and flight qualification of such components includes on top of many other actions thermal, structural and fatigue life analyses of chamber wall structures. Often, these analyses are based on half cooling channel + half fin Finite Element models of a tiny chamber wall section with symmetry conditions at the centerline of the cooling channel and the centerline of the fin. However, injector vicinity caused chamber wall temperature variations in circumferential direction of the chamber wall may cause localization effects of the deformation of the inner liner of chamber wall structures. Exemplary, an injector vicinity caused 20 K wall temperature variation is taken into account by a three-channel model. The influence of this variation to the distribution of the circumferential strain
distribution as well as to the post processing determined fatigue life is shown
On the Use of Antibiotics to Reduce Rhizoplane Microbial Populations in Root Physiology and Ecology Investigations
On the use of antibiotics to reduce rhizoplane microbial populations in root physiology and ecology investigations
Primary Liver Transplantation for Autoimmune Hepatitis: A Comparative Analysis of the European Liver Transplant Registry
The principal aim of this study was to compare the probability of and potential risk factors for death and graft loss after primary adult and pediatric liver transplantation in patients undergoing transplantation for autoimmune hepatitis (AIH) to those in patients undergoing transplantation for primary biliary cirrhosis (PBC; used as the reference group) or alcoholic cirrhosis (used as an example of a nonautoimmune liver disease). The 5-year survival of patients undergoing transplantation for AIH (n = 827) was 0.73 [95% confidence interval (CI) = 0.67-0.77]. This was similar to that of patients undergoing transplantation for alcoholic cirrhosis (0.74, 95% CI = 0.72-0.76, n = 6424) but significantly worse than that of patients undergoing transplantation for PBC (0.83, 95% CI = 0.80-0.85, n = 1588). Fatal infectious complications occurred at an increased rate in patients with AIH (hazard ratio = 1.8, P = 0.002 with PBC as the reference). The outcome of pediatric AIH patients was similar to that of adult patients undergoing transplantation up to the age of 50 years. However, the survival of AIH patients undergoing transplantation beyond the age of 50 years (0.61 at 5 years, 95% CI = 0.51-0.70) was significantly reduced in comparison with the survival of young adult AIH patients (0.78 at 18-34 years, 95% CI = 0.70-0.86) and in comparison with the survival of patients of the same age group with PBC or alcoholic cirrhosis. In conclusion, age significantly affects patient survival after liver transplantation for AN. The increased risk of dying of infectious complications in the early postoperative period, especially above the age of 50 years, should be acknowledged in the management of AIH patients with advanced-stage liver disease who are listed for liver transplantation. It should be noted that not all risk factors relevant to patient and graft survival could be analyzed with the European Liver Transplant Registry database. Liver Transpl 16:461-469, 2010. (C) 2010 AASLD