Ultrathin carbon support films for electron microscopy

Carbon support films only 4 to 6 angstroms thick have been made for use in electron microscopy. The determination of their thickness is based on geometrical calculation, electron scattering measurements, and elemental microanalysis.     

Cities, productivity, and quality of life

Technological changes and improved electronic communications seem, paradoxically, to be making cities more, rather than less, important. There is a strong correlation between urbanization and economic development across countries, and within-country evidence suggests that productivity rises in dense agglomerations. But urban economic advantages are often offset by the perennial urban curses of crime, congestion and contagious disease. The past history of the developed world suggests that these problems require more capable governments that use a combination of economic and engineering solutions. Though the scope of urban challenges can make remaining rural seem attractive, agrarian poverty has typically also been quite costly.     

Use of fungal biosystematics and molecular genetics in detection and identification of wood‐decay fungi for improved forest management

Advances in fungal biosystematics and molecular genetics have clarified relationships among the wood‐decay fungi and are providing new tools for their detection and identification. Species complexes of forest pathogens, including those within Heterobasidion, Armillaria, Laetiporus, and Phellinus, are being resolved. The ability to isolate fungal DNA directly from wood without in intermediate culturing step will greatly facilitate sampling and disease detection and has applications in forest disease management, hazard tree assessment, invasive species detection, and carbon cycling, sequestration and climate change research. Recent changes in fungal nomenclature and their application to forest pathology are discussed.     

Laboratory and environmental decay of wood–plastic composite boards: flexural properties

The flexural properties of wood–plastic composite (WPC) deck boards exposed to 9.5 years of environmental decay in Hilo, Hawaii, were compared to samples exposed to moisture and decay fungi for 12 weeks in the laboratory, to establish a correlation between sample flexural properties and calculated void volume. Specimens were tested for flexural strength and modulus, both wet and dry, at 23°C and 52°C. Some specimens degenerated to only 15% of original flexural strength. UV radiation had no impact on flexural properties of field-exposed boards; loss occurred mainly on the side opposite to the sun-exposed surface. The mechanism of the aging process on colonization of WPC by fungi was examined and is consistent with development of slow crack growth in the polyethylene matrix combined with wood decay by fungi. Wood particle decay, moisture, and elevated temperature were the major factors causing composite degradation, indicated by accumulation of voids and a severe decrease in flexural properties. To simulate long-term field impact (including decay) on WPC flexural properties in the laboratory, conditioning of specimens in hot water for an extended period of time is required. Exposure to water (70°C/5 days) was adequate for simulating long-term composite exposure in Hawaii of 4?×?15?×?86 mm³ specimens.     

Detection of pathogenic micro-organisms--a contribution to discussion

When applying methods for the detection of pathogenic micro-organisms in foodstuffs, information on the distribution of the target organism in the foodstuff submitted to a test should be available. The sampling plan used should allow to detect the presence of low levels of the target organism with a high probability. The individual steps of a detection procedure (pre-enrichment, selective enrichment, isolation and confirmation) need careful examination. It is important that inoculation of low levels of the target organism leads to successful enrichment even in the presence of relatively large numbers of competing organisms. In cases where competing micro-organisms form suspect colonies, there is a risk that false-negative results are obtained, because colonies of the target organism may not be isolated. Collaborative trials have to be carried out to assess the performance of presence/absence tests. Meaningful results are obtained only, if the test samples contain low levels of the target organism and if the effect of competing micro-organisms is checked. While it can hardly be disputed that the determination of the sensitivity and specificity of the test method provides valuable information, this cannot be said for "accordance" and "concordance", two recently proposed parameters which correspond to repeatability and reproducibility in quantitative tests. A better alternative may be to specify the probability to obtain two positive results, when analysing samples containing the target organism under repeatability or reproducibility conditions. In an analogous way, the probability to obtain two negative results with samples containing competing micro-organisms, but not the target organism, could be specified.     

Laboratory and exterior decay of wood–plastic composite boards: voids analysis and computed tomography

After exposure in the field and laboratory soil block culture testing, the void content of wood–plastic composite (WPC) decking boards was compared to unexposed samples. A void volume analysis was conducted based on calculations of sample density and from micro-computed tomography (microCT) data. It was found that reference WPC contains voids of different sizes from the micrometer range up to several cubic millimeters. Large voids were unevenly distributed within the composite sample. Void size and volume increased after conditioning the WPC in water at 70°C. Depending on the effect of exposure conditions, fungal decay during laboratory soil block testing increased the size and volume of voids. For laboratory samples, the calculated void volume was much higher compared to microCT-detected voids because of the limited resolution of the instrument on relatively large samples with many nano- and microvoids present in the material. In both laboratory and field samples, the creation of the voids resulted in a significant decrease in composite density. Decay damage observed as an increase in the size and volume of voids was particularly severe for boards exposed in the field. The calculated void volume in such samples was in reasonable agreement with voids detected by microCT.     

The N-acyl homoserine-lactone depleted Rhizobium radiobacter mutant RrF4NM13 shows reduced growth-promoting and resistance-inducing activities in mono- and dicotyledonous plants

Journal of Plant Diseases and Protection - The Alphaproteobacterium Rhizobium radiobacter (syn. Agrobacterium tumefaciens, “A. fa brum”) can live in close association with the...     

A decision support tool for response to global change in marine systems: the IMBER‐ADApT Framework

Global change is occurring now, often with consequences far beyond those anticipated. Although there is a wide range of assessment approaches available to address‐specific aspects of global change, there is currently no framework to identify what governance responses have worked and where, what has facilitated change and what preventative options are possible. To respond to this need, we present an integrated assessment framework that builds on knowledge learned from past experience of responses to global change in marine systems, to enable decision‐makers, researchers, managers and local stakeholders to: (i) make decisions efficiently; (ii) triage and improve their responses; and (iii) evaluate where to most effectively allocate resources to reduce vulnerability and enhance resilience of coastal people. This integrated assessment framework, IMBER‐ADApT is intended to enable and enhance decision‐making through the development, a typology of case‐studies providing lessons on how the natural, social and governance systems respond to the challenges of global change. The typology is developed from a database of case‐studies detailing the systems affected by change, responses to change and, critically, an appraisal of these responses, generating knowledge‐based solutions that can be applied to other comparable situations. Fisheries, which suffer from multiple pressures, are the current focus of the proposed framework, but it could be applied to a wide range of global change issues. IMBER‐ADApT has the potential to contribute to timely, cost‐effective policy and governing decision‐making and response. It offers cross‐scale learning to help ameliorate, and eventually prevent, loss of livelihoods, food sources and habitat.     

Nitrogen use efficiency of microalgae application in wheat compared to mineral fertilizer

Background

Wastewater from sewage treatment plants contains high levels of nutrients, which can be used for plant nutrition. Classical wastewater treatment plants use complex microbial consortia of autotrophic and heterotrophic microorganisms for biological wastewater treatment. Certain autotrophic microalgae (e.g., species of the genera Chlorella, Scenedesmus, and Pediastrum) accumulate nutrients from wastewater very effectively.

Aims

We investigated the potential of microalgae biomass obtained from a prototype wastewater treatment plant as a source of nutrients for crops, focusing on nitrogen.

Methods

We provided wheat plants with different levels of algae biomass equivalent to 60, 120, and 180 kg N per hectare or with mineral fertilizer (N, P, and K) equivalent to the amounts contained in the algal biomass. Physiological and phenotypic traits were measured during growth, including vegetation indices, photosynthetic performance, growth, and nitrogen use efficiency (NUE). In addition, the adundances of Bacteria, Archaea and fungi and genes of ammonium oxidizing Bacteria and Archaea were determined in the rhizosphere of differently fertilized plants.

Results

Microalgal application at fertilizer levels of 120 and 180 kg N ha^–1 showed significantly improved physiological performance, growth, yield and nutrient uptake compared to the unfertilized control. Nevertheless, their yields and NUE were lower than with the application of equal amounts of mineral fertilization, while the adundance of rhizosphere microbes and ammonia-oxidizing microorganisms were not significantly affected.

Conclusions

Microalgae from wastewater treatments form a suitable source of organic fertilizer for wheat plants with only moderate reductions in N use efficiency compared to mineral fertilizer.