Elastic constants of wood determined by ultrasound using three geometries of specimens

Knowledge of the twelve elastic constants of wood—three moduli of elasticity (E _L, E _R, and E _T), three shear moduli (G _LR, G _LT, and G _RT), and six Poisson’s ratios (μ _LR, μ _RL, μ _RT, μ _TR, μ _LT, and μ _TL)—is essential in some applications, e.g., in simulations or structural calculation software. The methodology for determining these parameters has been developed by different authors, but typically with different samples, which prevents conclusive comparisons. The aim of the present study was to assess both the methods and associated results of using ultrasound technology on three geometric specimens—multifaceted discs, polyhedrons, and prisms—to characterize samples from three wood species: Eucalyptus saligna, Apuleia leiocarpa, and Goupia glabra. The results from the ultrasound and static compression tests on the prism were obtained from another study by the authors’ group and used for a comparative analysis because the species belonged to the identical sample. In general, the moduli of elasticity and shear moduli were statistically equivalent to those obtained by the static test for the three geometries of the specimens. The results of the Poisson’s ratios depended on the type and geometry of the specimens. The polyhedral geometry showed the best results, whereas the prismatic results were the least suitable. From a methodological perspective, the polyhedron was easier to apply.     

Risk factors perceived predictive of ISA spread in Chile: Applications to decision support

Aquaculture is anticipated to be a critical element in future solutions to global food shortage. However, diseases can impede industry efficiency and sustainability. Consequently, diseases can and have led to dramatic re-structuring in industry or regulatory practices. The emergence of infectious salmon anemia (ISA) in Chile is one such example. As in other countries, many mitigations were instituted universally, and many incurred considerable costs as they introduced a new layer of coordination of farming activities of marine sites within common geographic areas (termed ‘neighborhoods’ or ‘barrios’). The aggregate response led to a strong reduction in ISA incidence and impact. However, the relative value of individual mitigations is less clear, especially where response policies were universally applied and retrospective analyses are missing ‘controls’ (i.e., areas where a mitigation was not applied). Further, re-focusing policies around disease prevention following resolution of an outbreak is important to renew sustainable production; though, again, field data to guide this shift in purpose are often lacking. Expert panels can offer timely decision support in the absence of empirical data.     

A Real-Time PCR for Detection and Quantification of Mycoplasma ovipneumoniae

A real-time PCR for detection and quantification of M. ovipneumoniae was developed using 9 recently sequenced M. ovipneumoniae genomes and primers targeting a putative adhesin gene p113. The assay proved to be specific and sensitive (with a detection limit of 22 genomic DNA) and could quantify M. ovipneumoniae DNA over a wide linear range, from 2.2 × 10² to 2.2 × 10⁷ genomes.     

Evaluation and variation in response to infection with Puccinia striiformis and Puccinia recondita of local wheat landraces

The purpose of this study was to identify the species of local landraces of wheat (Triticum spp.), held in the Israel Gene Bank, to evaluate them for basic characters and to assess their response to infection by two rust fungi under artificial inoculation conditions. One-hundred-thirty one seed samples were collected from local or Beduin farmers during 1978–1981 throughout the Galilee, Mt. Gilboa. Judean Desert and the south Negev. The samples were collected and stored in the Israel Gene Bank without any characterization or evaluation. Each accession was planted in a 1 m row at Bet Dagan and grown under favorable conditions for plant growth and rust development. Determination of the species, data of plant height, days to heading and reaction of the landraces to artificial inoculation with a composite inoculum of Puccinia recondita and P. striiformis were collected from each row. A small part of the landraces collection consisted of mixed populations of T. durum and T. aestivum plants, where one of the two species was predominant. One-hundred-fourteen and 17 accessions from this collection represented, respectively, Triticum durum and T. aestivum Israel landraces. Large variations were found for all the characters examined. Of the total accessions, 6.5% (8 accessions) and 32% (42 accessions) were resistant, respectively, to yellow- and leaf-rust. It was concluded that the diversified populations of the local landraces of wheat can be used as a source not only for genes affecting basic characters such as plant height and heading date, but also for resistance to leaf rust and yellow rust. This revised version was published online in July 2006 with corrections to the Cover Date.     

Rice (Oryza sativa L.) germplasm suitable for direct sowing under flooded soil surface

Summary Screening for rice germplasm which can establish seedling from flooded soil was conducted using 256 accessions of conserved germplasm from the International Rice Germplasm Center (IRGC) and 404 accessions from the International Network for Genetic Evaluation for Rice (INGER), IRRI. IRGC germplasm represented broad genetic diversity while INGER germplasm involved desirable agronomic characters. Seeds germinated for 2 d were planted at 25 mm depth in seedling trays. The trays were then submerged to a depth of 30–50 mm. Seedling establishment was evaluated by analyzing leaf development, seedling height, and percentage establishment 15 d after planting. Eight percent and 2% of IRGC and INGER germplasm, respectively, were identified statistically as superior to the control semidwarf IR varieties. Among the superior germplasm were those from Northeast India and Bangladesh which were adapted to deepwater and early summer rainfed lowland cultures. These could be utilized as parents in breeding programs which aim to develop varieties suitable for direct seeding technology (i.e., germinated seeds are sown under the surface of flooded soil).     

A process to provide harmonised criteria for the selection of indicators for pesticide risk reduction within the framework of the sustainable use directive

In October 2009, the Council of the European Union adopted the Directive on Sustainable Use of Pesticides (EU 128/2009/EC). This directive establishes a framework to achieve the sustainable use of pesticides by reducing the risk and impacts of pesticide use on both human health and the environment, and promoting the use of integrated pest management and of alternative approaches or techniques. These risks thus need to be assessed using appropriate risk indicators. The OPERA Research Centre organised an expert working group and has had several consultations with stakeholders in order to identify a common way of thinking in evaluating and identifying the factors that should be considered in selecting each indicator. Harmonised criteria have been suggested to allow the selection of the most appropriate indicators, focusing on the use phase of pesticide, as requested by the sustainable use directive. The proposed methodology has led to a sharing of perspectives and knowledge between the experts involved, and some principles have been identified to help national regulatory institutions to estimate general trends in pesticide risk reduction .     

Unknown‐parent groups in single‐step genomic evaluation

In single‐step genomic evaluation using best linear unbiased prediction (ssGBLUP), genomic predictions are calculated with a relationship matrix that combines pedigree and genomic information. For missing pedigrees, unknown selection processes, or inclusion of several populations, a BLUP model can include unknown‐parent groups (UPG) in the animal effect. For ssGBLUP, UPG equations also involve contributions from genomic relationships. When those contributions are ignored, UPG solutions and genetic predictions can be biased. Options to eliminate or reduce such bias are presented. First, mixed model equations can be modified to include contributions to UPG elements from genomic relationships (greater software complexity). Second, UPG can be implemented as separate effects (higher cost of computing and data processing). Third, contributions can be ignored when they are relatively small, but they may be small only after refinements to UPG definitions. Fourth, contributions may approximately cancel out when genomic and pedigree relationships are constructed for compatibility; however, different construction steps are required for unknown parents from the same or different populations. Finally, an additional polygenic effect that also includes UPG can be added to the model.     

Soil organic carbon stocks in Veracruz State (Mexico) estimated using the 1:250,000 soil database of INEGI: biophysical contributions

Purpose

In this study, we quantified soil organic carbon (SOC) stocks and analyzed their relationship with biophysical factors and soil properties.

Materials and methods

The study region was Veracruz State, located in the eastern part of Mexico, covering an area of 72,410 km². A soil database that contains physicochemical analyses of soil horizons such as carbon concentration data was the source of information used in this study. The database consisted of 163 soil profiles representing 464 genetic horizons. Statistical analysis was used to investigate the effect of each factor (climate, altitude, slope) on SOC stock to 0.50 m depth and to assess differences in the distribution of SOC stock in terms of soil depth (0.0–0.20, 0.20–0.40, 0.40–0.60, 0.60–0.80, 0.80–1.0 m) and land use. In order to compute the spatial distribution of SOC stock to 0.50 m depth based on the soil sampling location, the kriging method was used.

Results and discussion

Results indicated that SOC stock (0.50 m depth) ranged between 0.44 and 41.2 kg C m^?2. Regression analysis showed that SOC stocks (0.50 m depth) are negatively correlated with temperature (r?=??0.38; P?<?0.001) and positively correlated with altitude (r?=?0.40; P?<?0.001) and slope (r?=?0.40; P?<?0.001). In addition, by multiple regression, temperature combined with precipitation explained more SOC stock variations (r?=?0.43; P?<?0.001) than the regression model with precipitation (r?=?0.13; P?=?0.16) alone. Also, slope combined with temperature and precipitation explained more SOC stock variations (r?=?0.46; P?<?0.001) than the regression model with slope alone. Forest lands, grasslands, and croplands have higher SOC stocks in the 0.0–0.20-m soil layer than in deeper layers. On average, forest lands, grasslands, croplands, and other lands (wetland and dunes) had a SOC stock of 13.6, 14.6, 15.1, and 8.5 kg C m^?2 at 1 m depth, respectively. Soil color correlated (?0.25 ≤ r ≤ ?0.89) with SOC content.

Conclusions

Overall, these results indicate the influence of major interactions between biophysical factors and SOC stocks. This research indicated that SOC stock decreased with soil depth, but with slight variations depending on land use. Thus, there remains a need for more SOC data that include an improved distribution of soil sampling points in order to entirely understand the contributions of biophysical factors to SOC stocks in Veracruz State.     

Comparing chemical-enhanced washing and waste-based stabilisation approach for soil remediation

Purpose

This study aimed to compare the effectiveness of chemical-enhanced soil washing (with chelating agents, humic substances and inorganic acids) and soil stabilisation by inorganic industrial by-products (coal fly ash, acid mine drainage sludge and zero-valent iron) and organic resource (lignite) for timber treatment site remediation.

Materials and methods

Both remediation options were assessed in terms of extraction/leaching kinetics and residual leachability (toxicity characteristic leaching procedure, TCLP) of the major risk drivers, i.e. Cu and As.

Results and discussion

In chemical-enhanced soil washing, chelating agents only minimised the Cu leachability. Humic substances were ineffective while inorganic acids reduced the As leachability to the detriment of the soil quality. For the waste-stabilised soil, the short-term leaching potential (72 h) and long-term TCLP leachability (9 months) revealed that Fe-/Al-/Ca-rich AMD sludge and coal fly ash sequestered As through adsorption and (co-)precipitation, while carbonaceous lignite stabilised Cu with oxygen-containing functional groups. The short-term and long-term leaching of Cu and As into the soil solution was negligible in the presence of the waste materials. However, the waste-stabilised soil did not maintain sufficient Cu stability in the TCLP tests, in which acetate buffer induced significant mineral dissolution of the waste materials.

Conclusions

These results suggest that chelant-enhanced washing (significant reduction of Cu leachability) may be augmented with subsequent stabilisation with inorganic waste materials (effective control of As leachability), thus minimising the environmental risks of both Cu (heavy metal) and As (metalloid) while preserving the reuse value of the soil. Additional tests under field-relevant conditions are required to provide a holistic performance evaluation.