Minimizing ammonia volatilization from urea,improving lowland rice (cv. MR219) seed germination,plant growth variables,nutrient uptake,and nutrient recovery using clinoptilolite zeolite

The anionic nature and high cation exchange capacity (CEC) of clinoptilolite zeolite can be exploited to reduce ammonia (NH₃) loss from urea and to improve soil chemical properties to increase nutrient utilization efficiency in lowland rice cultivation. A closed-dynamic airflow system was used to determine NH₃ loss from treatments (20, 40, and 60 g clinoptilolite zeolite pot^?1). Seed germination study was conducted to evaluate the effects of clinoptilolite zeolite on rice seed germination. A pot study was conducted to determine the effects of clinoptilolite zeolite on rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. Standard procedures were used to determine NH₃ loss, rice plant height, number of leaves, number of tillers, dry matter production, nutrient uptake, nutrient recovery, and soil chemical properties. Application of clinoptilolite zeolite (15%) increased shoot elongation of seedlings and significantly reduced NH₃ loss (up to 26% with 60 g zeolite pot^?1), and increased number of leaves, total dry matter, nutrient uptake, nutrient recovery, soil pH, CEC, and exchangeable Na⁺. Amending acid soils with clinoptilolite zeolite can significantly minimize NH₃ loss and improve rice plant growth variables, nutrient uptake, nutrient recovery, and soil chemical properties. These findings are being validated in our ongoing field trials.     

Potential of weed seedbanks for managing weeds: a review of recent New Zealand research

Weed seedbanks are the primary source of weeds in cultivated soils. Some knowledge of the weed seedbank may therefore be appropriate for integrated weed management programs. It would also be very useful in planning herbicide programs and reducing the total herbicide use. However, a number of problems are inherent in the estimation of the seedbank size for arable weeds that usually have annual life cycles. In a long-term research project we have investigated the dynamics of weed seedbanks in corn fields for the past 8 years. Specific studies have included (i) developing cheap and efficient methods for estimating the weed seedbank; (ii) developing guidelines for efficient soil sampling (including the number and size of samples); (iii) influence of cultivation methods on weed seed distribution; (iv) mapping the spatial variability of the seedbank; (v) estimating the rate of seedbank decline for certain weed species; and (vi) assessing the potential of using the weed seed content in the soil to predict future weed problems. This paper reviews and summarizes the results of our research on the above aspects. The strong correlation between seedlings emerged in the greenhouse and seeds extracted in the laboratory for the most abundant weed species has demonstrated the potential for using the weed seed content of the soil to predict future weed infestations. The next step is to establish correlations with field emergence under commercial conditions using the sampling guidelines developed in our studies. Subsequently, we aim to offer the weed seedbank estimation as a commercial service to farmers for planning the most appropriate weed management options.     

The conservation of the endangered Mediterranean common dolphin (Delphinus delphis): Current knowledge and research priorities

1. Preservation of endangered species is now recognized as a relevant component of regional and global conservation actions achieved through the maintenance of the remaining populations in a favourable conservation status. The Mediterranean common dolphin (Delphinus delphis) is listed as an Endangered subpopulation in the International Union for Conservation of Nature Red List, with declining numbers in some of the areas where it has been studied for numerous years. Prey depletion, fisheries bycatch, pollution, health risks, and climate change are among the recognized threats that the species is facing in the region.
2. The existing national, regional, and international legislation pertinent to Mediterranean countries should aid greater science–policy–management integration and support innovative research and monitoring towards effective conservation. The challenges inherent in studying the pelagic D. delphis should not preclude the use of long-term, year-round, multiplatform surveys, side by side with the latest molecular tools, which aid our understanding of its populations' genetic diversity, resistance to diseases, and resilience in a semi-enclosed fast-changing sea.
3. Addressing the multiplicity of problems confronting the species requires collaborative effort at all levels to share and merge resources, data, and expertise more efficiently. In this review, we provide an overview of the current knowledge on the Mediterranean common dolphin, the main threats, and knowledge gaps that are priorities for addressing its conservation, while providing clear recommendations for effectively safeguarding the species and its habitat at both local and regional levels.

     

Morphological changes in carp epithelial cells infected with Aeromonas hydrophila

The in vitro interaction of Aeromonas hydrophila with epithehoma papillosum cells of carp (EPC) was studied. All the virulent and type strains invaded and multiplied inside EPC cells. Morphological changes were induced by the virulent and type strains during the processes of invasion and intracellular replication. Among the virulent group, strain PPD134/91 required the shortest time (30 min post-infection) to induce cytopathic effects in the EPC monolayers. The EPC cells infected with PPD 134/91 became retracted and condensed, lost their attachment abilities, and eventually disintegrated. Confocal microscopy revealed that tubular structures measuring 0.77 ± 0.19 μm appeared to connect the retracted EPC cells. The cytopathic effect was attributed to the growing and metabolically active bacteria. Avirulent strains such as L37 did not multiply nor induce cytopathic effects in the EPC monolayers.     

含气率对小流量下混流式混输泵轴系振动的影响

振动是反映混输泵运行稳定性的关键指标,液体含气率对混输泵的振动强度有重要影响.为探究小流量工况下含气率变化对混输泵轴系振动的影响规律,该研究以某3级混流式气液混输泵为研究对象,采用建立的多通道振动测试系统采集小流量工况下混输泵输送不同含气率的水时主轴和轴承座的振动信号,然后分析水中含气率对主轴和轴承座振动特性的影响规律...     

In vitro inhibition of epithelial cell invasion by Aeromonashydrophila Vibrio species by fish Aeromonas hydrophila major adhesin

A virulent strain of Aeromonas hydrophila (PPD 134/91) was obtained from the Primary Production Department, Singapore. Its major adhesin was isolated and purified by potassium thiocyanate extraction and Bio-Gel P-100 gel filtration. The ability of the protein in peak 1, termed major adhesin, to inhibit bacteria from adhering to and invading host cells was studied in vitro using epithelioma papillosum cells of carp (EPC). Results showed that a concentration of 10 μg ml^–1 of this major adhesin could competitively inhibit 28% of A. hydrophila PPD 134/91 from invading EPC cells in vitro. When the concentration was increased to 40 μg ml^–1, the major adhesin significantly cross-inhibited nine other virulent or weakly virulent strains of A. hydrophila. In addition, the major adhesin significantly inhibited not only another bacterial strain from the same family, Aeromonas sobria, but also strains of Vibrio spp. tested. Therefore, we suggest that the major adhesin of this virulent A. hydrophila strain has the potential to be used as a vaccine against the heterogeneous Aeromonas and Vibrio species.     

Simultaneous Extraction and Fractionation of Fish Oil from Tuna By-Product Using Supercritical Carbon Dioxide (SC-CO2)

ABSTRACT

Fish oil was extracted and simultaneously collected into six fractions based on molecular weight and the chain length of triglycerides in terms of fatty acid constituents without splitting of the triglycerides, using supercritical carbon dioxide (SC-CO₂) at optimized conditions of 40 MPa, 65°C, and a flow rate 3 mL min^?1. In each type of fractionation, the first fraction (F1) was rich in saturated fatty acids (SFA; 52.57 to 61.26%), followed by monounsaturated fatty acids (MUFA; 22.17 to 23.22%) and polyunsaturated fatty acids (PUFA; (0.54 to 20.37%); the sixth fraction (F6) was rich in PUFA (48.93%), followed by MUFA (33.59%) and SFA (13.61%). It was obvious that short-chain fatty acids were extracted at an earlier fraction; therefore, the latter fractions were dominant in long-chain fatty acids, especially MUFA and PUFA. Thus, omega-3 fish oil (last three fractions) was successfully separated to be used as a value-added health product.     

Reducing Soil Phosphorus Fixation to Improve Yield of Maize on a Tropical Acid Soil Using Compost and Biochar Derived from Agro-Industrial Wastes

Phosphorus is an essential element required to maintain profitable crop production. Most soils of the tropics, such as Ultisols, are acidic and fix phosphorus because of their characteristically high contents of aluminium and iron. Compost and biochar could be used to mitigate phosphorus fixation by reducing the phosphorus sorption sites. This study aimed to: (i) improve soil phosphorus availability, nutrient uptake, and yield of maize using biochar and pineapple leaf residue compost; and (ii) determine if the use of biochar and compost could exert a residual effect on phosphorus nutrition in the second cycle of the field trial. Field trials were carried out using a Zea mays L. hybrid as the test crop. At harvest, the plants were harvested, partitioned into leaves and stems, and analyzed. Soil samples were also collected and analyzed. Ears were harvested to determine the yield from each treatment. The results suggest that the soil total phosphorus and available phosphorus recovered from the treatments with the organic amendments were higher compared with the non-organic amendments. The availability of soil nutrients (nitrogen, potassium, calcium, magnesium, and sodium) in the soils and yield of maize were higher in the treatments with the organic amendments in the first and second field trials. These results further confirm that amending chemical fertilizers with organic amendments have a larger residual effect than chemical fertilizers only. Amending chemical fertilizers with organic amendments can be used to ameliorate phosphorus fixation of acid soils to improve maize production on acid soils.