Prioritizing R&D for the U.S. Department of Energy's Weapons Complex Clean-Up

Prioritizing the U.S. Department of Energy's (DOE's) targeted R&D program supporting weapons-complex clean-up has been problematic. Considering issues common to all R&D evaluation, linking R&D prioritization to clean-up project prioritization, the latter aligned with institutional goals, offers a pragmatic solution. This method is illustrated with results of a clean-up prioritization model of DOE's Oak Ridge National Laboratory site.     

The Distribution of Tree Species in the Ridge Landscape (Southern Karelia)

The distribution of tree species in the landscape was studied using the approach based on the comparison of the ecological requirements of species and the properties of ecotopes distinguished by their position in the relief and peculiarities of basement rocks. The types and specificity of ecological regimes were determined for the typical ecotopes of the southern Karelian ridge landscape. The main environmental and successional factors determining the distribution of seven forest-forming tree species in the ecotopes of this landscape were identified. The results of this work can provide a basis for the prognosis of forest vegetation in the landscape studied.     

Assessment of oxidative stress due to exposure to pesticides in plasma and urine of traditional limited-resource farm workers: Formation of the DNA-adduct 8-hydroxy-2-deoxy-guanosine (8-OHdG)

The objective of this study was to assess the risk of genotoxicity caused due to oxidative stress using plasma and urinary levels of 8-hydroxy-2-deoxyguanosine (8-OHdG) in farm workers for six months during a growing season. Blood and urine samples were collected once a month for six months (June to November 2003) from farm workers (n = 15) and urban unexposed controls (n = 10). Plasma and urinary levels of 8-OHdG were evaluated by Enzyme Linked Immunosorbent Assay (ELISA) technique. There was no significant difference in the urinary levels of 8-OHdG between the farm workers and the control group, but there was an approximately four-fold increase in mean values of plasma 8-OHdG levels in the farm worker group (P ≤ 0.05).     

Differential physiological,ultramorphological and metabolic responses of cotton cultivars under cadmium stress

Cadmium (Cd) stress may cause serious physiological, ultramorphological and biochemical anomalies in plants. Cd-induced physiological, subcellular and metabolic alterations in two transgenic cotton cultivars (BR001, GK30) and their parent line (Coker 312) were evaluated using 10, 100 and 1000 μM Cd. Germination, fresh biomass of roots, stems and leaves were significantly inhibited at 1000 μM Cd. Root volume tolerance index significantly increased (124.16%) in Coker 312 at 1000 μM Cd. In non-Cd stressed conditions, electron micrographs showed well-configured root meristem and leaf mesophyll cells. At 1000 μM Cd, greater ultramorphological alterations were observed in BR001 followed by GK30 and Coker 312. These changes were observed in nucleus, vacuoles, mitochondria and chloroplast. Dense precipitates, probably Cd, were seen in vacuoles, which were also attached to the cell walls. A considerable increase in number of nuclei, vacuoles, starch granules and plastoglobuli was observed in the electron micrographs of both roots and leaves at 1000 μM Cd. MDA contents were higher in roots of BR001 at 1000 μM Cd. Mean values of SOD activity in leaves of both BR001 and GK30 at 1000 μM Cd significantly increased as compared to the controls. POD activity in roots of BR001 and Coker 312 was greater at all Cd (10, 100, 1000 μM) levels over the control. Regarding APX, highest percent increase (71.64%) in roots of GK30 at 1000 μM Cd was found. Non-significant differences in CAT activity were observed at all levels of Cd stress in leaves of BR001 and GK30. Both transgenic cotton cultivars and their parental line invariably responded towards Cd stress. However, Coker 312 showed Cd-resistant behavior as compared to its progeny lines (BR001 and GK30).     

Comparative phototoxicity of nanoparticulate and bulk ZnO to a free-living nematode Caenorhabditis elegans: the importance of illumination mode and primary particle size

The present study evaluated phototoxicity of nanoparticulate ZnO and bulk-ZnO under natural sunlight (NSL) versus ambient artificial laboratory light (AALL) illumination to a free-living nematode Caenorhabditis elegans. Phototoxicity of nano-ZnO and bulk-ZnO was largely dependent on illumination method as 2-h exposure under NSL caused significantly greater mortality in C. elegans than under AALL. This phototoxicity was closely related to photocatalytic reactive oxygen species (ROS) generation by the ZnO particles as indicated by concomitant methylene blue photodegradation. Both materials caused mortality in C. elegans under AALL during 24-h exposure although neither degraded methylene blue, suggesting mechanisms of toxicity other than photocatalytic ROS generation were involved. Particle dissolution of ZnO did not appear to play an important role in the toxicity observed in this study. Nano-ZnO showed greater phototoxicity than bulk-ZnO despite their similar size of aggregates, suggesting primary particle size is more important than aggregate size in determining phototoxicity.     

Does the stress tolerance of mixed grassland communities change in a future climate? A test with heavy metal stress (zinc pollution)

Will species that are sensitive/tolerant to Zn pollution still have the same sensitivity/tolerance in a future climate? To answer this question we analysed the response of constructed grassland communities to five levels of zinc (Zn) supply, ranging from 0 to 354 mg Zn kg⁻¹ dry soil, under a current climate and a future climate (elevated CO₂ and warming). Zn concentrations increased in roots and shoots with Zn addition but this increase did not differ between climates. Light-saturated net CO₂ assimilation rate (A_sat) of the species, on the other hand, responded differently to Zn addition depending on climate. Still, current and future climate communities have comparable biomass responses to Zn, i.e., no change in root biomass and a 13% decrease of above-ground biomass. Provided that the different response of A_sat in a future climate will not compromise productivity and survival on the long term, sensitivity is not altered by climate change.     

Texture Analysis for Mapping Tamarix parviflora Using Aerial Photographs along the Cache Creek, California

Natural color photographs were used to detect the coverage of saltcedar, Tamarix parviflora, along a 40 km portion of Cache Creek near Woodland, California. Historical aerial photographs from 2001 were retrospectively evaluated and compared with actual ground-based information to assess accuracy of the assessment process. The color aerial photos were sequentially digitized, georeferenced, classified using color and texture methods, and mosaiced into maps for field use. Eight types of ground cover (Tamarix, agricultural crops, roads, rocks, water bodies, evergreen trees, non-evergreen trees and shrubs (excluding Tamarix)) were selected from the digitized photos for separability analysis and supervised classification. Due to color similarities among the eight cover types, the average separability, based originally only on color, was very low. The separability was improved significantly through the inclusion of texture analysis. Six types of texture measures with various window sizes were evaluated. The best texture was used as an additional feature along with the color, for identifying Tamarix. A total of 29 color photographs were processed to detect Tamarix infestations using a combination of the original digital images and optimal texture features. It was found that the saltcedar covered a total of 3.96 km² (396 hectares) within the study area. For the accuracy assessment, 95 classified samples from the resulting map were checked in the field with a global position system (GPS) unit to verify Tamarix presence. The producer's accuracy was 77.89%. In addition, 157 independently located ground sites containing saltcedar were compared with the classified maps, producing a user's accuracy of 71.33%.     

A national ozone biomonitoring program--results from field surveys of ozone sensitive plants in northeastern forests (1994-2000)

Ozone biomonitoring is a detection and monitoring techniquethat involves documenting ozone-induced visible injury toknown ozone-sensitive species under conditions of ambientexposure. The USDA Forest Service administers a long-term,nationwide ozone biomonitoring program to address public andscientific concerns about ozone impacts on forest health. Asystematic grid is used as the basis for biomonitoring sitelocations. At each site, trained field crews evaluate amaximum of thirty plants of up to six species and record the amount and severity of leaf-injury on individualplants. Injury from ozone was found more often on biomonitoring sites in the eastern Unites States than in theinterior or west-coast areas. Further results from thenortheast reveal that in any year, there is a higherpercentage of ozone-injured plants with more severe symptomsin areas with relatively high ozone concentrations than inareas with relatively low ozone. In very dry years (e.g.,1999) the percentage of injured plants and injury severityestimates are both sharply reduced even though ambient ozoneexposures are high. These findings demonstrate thatbiomonitoring data provide meaningful evidence of when highozone concentrations during the growing season have biologicalsignificance. Any assessment of ozone stress in the forestenvironment must include both biomonitoring (i.e., plantresponse) and air quality data to be complete.     

南岳森林群落生物多样性研究(Ⅱ)广济寺森林群落植物物种多样性测定

本文根据实地调查资料及其统计分析结果,选用了24个物种多样性指数公式,并采用重要值、株数或鲜重以及优势度或盖度等作为测度指标,对南岳广济寺森林群落植物物种多样性进行了研究。结果表明,南岳广济寺森林属落多样性较高,接近山地季雨林的水平;此外,不同测度指标对物种多样性指数计算值并无明显的规律性。     

南岳森林群落生物多样性研究(Ⅴ)上封寺森林群落植物物种多样性测定

本文根据对南岳上封寺森林群落野外实地考察以及研究结果,选用了24个有代表性的物种多样性测定公式,并采用重要值、株数或鲜重、优势度或盖度作为测度指标对南岳上封寺森林群落植物物种多样性进行了研究。结果表明,南岳上封寺森林群落植物物种多样性水平较高,但又低于南岳广济寺。此外,不同测度指标对物种多样性指数的结果并无明显的规律性变化。