Visualizing individual nitrogen dopants in monolayer graphene

In monolayer graphene, substitutional doping during growth can be used to alter its electronic properties. We used scanning tunneling microscopy, Raman spectroscopy, x-ray spectroscopy, and first principles calculations to characterize individual nitrogen dopants in monolayer graphene grown on a copper substrate. Individual nitrogen atoms were incorporated as graphitic dopants, and a fraction of the extra electron on each nitrogen atom was delocalized into the graphene lattice. The electronic structure of nitrogen-doped graphene was strongly modified only within a few lattice spacings of the site of the nitrogen dopant. These findings show that chemical doping is a promising route to achieving high-quality graphene films with a large carrier concentration.     

Virulence-associated protein characterisation of Rhodococcus equi isolated from bovine lymph nodes

Rhodococcus equi has a low pathogenicity in cattle, but it occasionally causes lymph node granulomas, which are detected at abattoir post mortem inspection, and must be distinguished from tuberculous granulomas. Lymph node lesions were detected in 6719 cattle, from a total of 3,263,622 cattle examined post mortem in abattoirs, in the Republic of Ireland, during 1997 and 1998. Histological examination was performed on all lesions, principally for the purpose of identifying animals with tuberculosis. A total of 1122 of the lesions were cultured on blood agar and on Stonebrinks and Lowenstein-Jensen medium containing pyruvate, because the histological findings were difficult to interpret or were suggestive of R. equi infection. R. equi was isolated from 264 lesions. Almost all of the R. equi granulomas were confined to a single lymph node, and were present predominantly in the retropharyngeal, bronchial and mediastinal lymph nodes. R. equi granulomas were present in a significantly higher proportion of the lesions detected in steers and heifers compared to cows. The prevalence in the total population of 3.3 million cattle examined post mortem was 0.008%. The 15-17kDa antigens, associated with virulence in this organism, and the 20kDa antigen, associated with intermediate virulence, were not detected in isolates from 146 cattle, analysed by immunoblot assays. A PCR assay to detect the plasmid gene encoding the 15-17kDa antigens was also negative for isolates from these 146 animals. Plasmids were not detected in 30 isolates which were examined.     

Estimating the ecological,economic and social impacts of ocean acidification and warming on UK fisheries

Assessments of the combined ecological impacts of ocean acidification and warming (OAW) and their social and economic consequences can help develop adaptive and responsive management strategies in the most sensitive regions. Here, available observational and experimental data, theoretical, and modelling approaches are combined to project and quantify potential effects of OAW on the future fisheries catches and resulting revenues and employment in the UK under different CO₂ emission scenarios. Across all scenarios, based on the limited available experimental results considered, the bivalve species investigated were more affected by OAW than the fish species considered, compared with ocean warming alone. Projected standing stock biomasses decrease between 10 and 60%. These impacts translate into an overall fish and shellfish catch decrease of between 10 and 30% by 2020 across all areas except for the Scotland >10 m fleet. This latter fleet shows average positive impacts until 2050, declining afterwards. The main driver of the projected decreases is temperature rise (0.5–3.3 °C), which exacerbate the impact of decreases in primary production (10–30%) in UK fishing waters. The inclusion of the effect of ocean acidification on the carbon uptake of primary producers had very little impact on the projections of potential fish and shellfish catches (<1%). The <10 m fleet is likely to be the most impacted by‐catch decreases in the short term (2020–50), whereas the effects will be experienced more strongly by the >10 m fleet by the end of the century in all countries. Overall, losses in revenue are estimated to range between 1 and 21% in the short term (2020–50) with England and Scotland being the most negatively impacted in absolute terms, and Wales and North Ireland in relative terms. Losses in total employment (fisheries and associated industries) may reach approximately 3–20% during 2020–50 with the >10 m fleet and associated industries bearing the majority of the losses.     

中国-全球MDF增长的领头羊

中密度纤维板(MDF)是世界上增长最快的木材产品之一.MDF的全球生产能力从1993年不到1000万m3增长到2002年的3 380万m3.根据已经交工的MDF项目,预计到2004年,全球生产能力超过4 000万m3.表明自1993年以来,生产能力年均增长率14.3%.     

A simple method for estimating nitrate removal from floodwaters in river marginal wetlands

Abstract. Soil cores from river marginal wetlands in the UK, France and Ireland, sampled and contained within PVC piping, were flooded with nitrate-N enriched water. Half of the cores were sterilized prior to flooding to destroy the denitrifying bacteria. The change in nitrate-N concentration in the floodwater was measured over time. It is argued that the observed nitrate depletion rates (from 0.4 to 2.3 kg/ha per day) may be identified With microbially-mediated denitrification. The results show the method to be a simple and direct procedure for the assessment of spatial variation in nitrate-sink capacity. The depth of the denitrifying layer at the soil-water interface was confirmed to be of the order of a few mm.     

美国木地板市场快速扩张

根据报道,2002年美国木地板销售总额达到18.7亿美元,1998年为13.5亿美元.在近几年的记录中这是第一年,即木地板的经营业绩超过2002年的总销售额为18.4亿美元的乙烯基地板.在过去5年里,硬木地板的销售额以年均增长率为8.4%的速度递增.     

Oil and meal characteristics of core and non-core safflower accessions from the USDA collection

Germplasm evaluation of ex situ collections is needed to document collection characteristics, enhance utilization, and to determine collection needs. The objectives of this study were to (1) provide oil and meal evaluation information for a major portion of the United States Department of Agriculture (USDA) safflower (Carthamus tinctorius L.) collection, (2) compare ranges, variances and means between 203 core and 797 non-core accessions, and (3) determine if region of origin could be differentiated based on accession oil and meal characteristics. Means of the core and non-core accessions differed for % oil, palmitic acid, stearic acid, -tocopherols, and phenolic glucosides (both bitter and cathartic) (P<0.05). Differences between linoleic acid, oleic acid and -tocopherol means were not significant, and the variance between core and non-core accessions differed only for palmitic acid. Thus the core was not fully representative of the non-core accessions, but did capture a large fraction of the diversity in oil and meal factors present. Accessions from the Americas, China, South-West Asia, and South-Central Asia were differentiated using canonical discriminate analysis, but these regions overlapped to varying degrees with the E. European, Mediterranean, and E. African regions. Variation in % oil and fatty acids were generally more important than tocopherols and phenolic glucosides in differentiating accessions on a regional basis. The check cultivars Montola 2001 (high oleic) and Morlin (high linoleic) had oil and fatty acid content comparable to the maximums found in the collection. The ranges for tocopherols and phenolic glucosides among collection accessions, however, exceeded those of the cultivars, suggesting that collection accessions could be useful for genetic manipulation of these factors.     

A temperature correction procedure for field-based soil denitrification experiments

Abstract. An equation is developed to permit temperature correction (to some chosen reference temperature) for field-based soil columns that measure the depletion of nitrate in the water column above a soil layer where denitrification occurs. The derivation is based on the assumption that the overall nitrate depletion is diffusion controlled by the nitrate flux from the water column into the soil and the soil denitrification obeys Michaelis-Menten kinetics. The expression is tested on results from a large soil column maintained in a greenhouse where natural temperature cycling occurred.