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31.
This study developed a new adsorbent, specifically activated carbon-loaded silver nanoparticles (AgNPs-AC) by coating the silver nanoparticles (AgNPs) onto activated carbon (AC). The obtained AgNPs-AC were characterized by scanning electron microscopy (SEM), energy-dispersive spectrometry (EDS), Fourier transform infrared spectroscopy (FTIR), and Brunauer-Emmett-Teller (BET). The ability of AgNPs-AC to remove methylene blue (MB) was evaluated using different experimental factors, these being pH solution, contact time, adsorbent dose, and initial MB concentration. Results indicated that the highest adsorption capacity of MB onto AgNPs-AC was obtained when the AC was loaded onto AgNPs at the impregnation ratio of 0.5% w/w for AC and AgNPs. The best conditions in which AgNPs-AC could remove MB were as follows: pH 10, contact time lasting 120 min, and adsorbent dose being 250 mg/25 mL solution. In this scenario, the maximum adsorption capacity of MB onto AgNPs-AC was 172.22 mg/g. The adsorption isothermal equilibrium was well described by the Langmuir, Freundlich and Sips models. The Sips equations had the highest correlation coefficient value (R2?=?0.935). The pseudo-first-order and pseudo-second-order kinetic models agree well with the dynamic behavior of the adsorption of dye MB on AgNPs-AC.  相似文献   
32.
A 2-year-old dwarf rabbit was referred for right forelimb lameness of 1-week duration. Physical examination and radiographic findings were consistent with an elbow luxation. Manual reduction under anesthesia was unsuccessful in correcting the luxated joint. A surgical approach was recommended to repair the rabbit elbow luxation. Transcondylar, transradial, and transulnar tunnels were drilled from lateral to medial with 2 suture prostheses being placed, 1 from the radius to the humerus and 1 from the humerus to the ulna. Analgesia was provided and the patient was reevaluated on days 2, 7, and 14 after the procedure. The luxation was reduced and no recurrence was noted a year following the surgical procedure. Circumferential suture prostheses, recently described with no reported postoperative complications in cats, can be used successfully in rabbits as evidenced in this case report.  相似文献   
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Genomes of animals as different as sponges and humans show conservation of global architecture. Here we show that multiple genomic features including transposon diversity, developmental gene repertoire, physical gene order, and intron-exon organization are shattered in the tunicate Oikopleura, belonging to the sister group of vertebrates and retaining chordate morphology. Ancestral architecture of animal genomes can be deeply modified and may therefore be largely nonadaptive. This rapidly evolving animal lineage thus offers unique perspectives on the level of genome plasticity. It also illuminates issues as fundamental as the mechanisms of intron gain.  相似文献   
35.
 从大名红皮花皱叶植株上通过蚜虫分离出一个分离物,能侵染许多茄科植物,在直果蔓陀蘿上表现为明显的脉暗症状。
经测定致死温点为55-56℃,稀释限点为200-300倍,适宜的酸碱度为pH6-9,在22℃下体外存活期6小时,在15-25℃下经过25天的自然干燥仍保有活力。抗药力极强,能抗85%酒精、50%硫酸铜液、19%甲醛液、2.5%单宁酸,而不失其致病力。桃蚜、棉蚜、玉米蚜、麦二义蚜、麦长鬚蚜都能传播此病毒。蚜虫在病株上吸食10分钟即能带毒,带毒的蚜虫在寄主植物上放饲10分钟以上即可传染,其传毒能力与虫口密度有密切关系,每次需有10头以上才能传染。本病毒在洋酸浆、直果蔓陀蘿、龙葵等指示植物上的病状与PYV所引起的症状有显著区别,对PYV的抗血清无明显的沉淀反应,在洋酸浆上与PYV之间的交互保护作用很小。  相似文献   
36.

Fineroots (≤ 2 mm diameter) are dynamic components of the forest ecosystems and play important role in water and nutrient acquisition in forests. These roots are sensitive to forest fertilization and therefore, the response of fineroots to nutrient application would provide better understanding of the forest carbon and nutrient dynamics that will be helpful in sustainable forest management plans. Two fertilization treatments, including (1) F400: 400 g P2O5 (16.5%)/tree and (2) F600: 600 g P2O5 /tree, and F0: control (without fertilization), were applied in an Acacia mangium plantation with a planting density of 1100 trees/ha (3 m?×?3 m). The evaluation of fineroot growth across seasons showed that fertilization significantly increased production and subsequent mortality and decomposition. The total decomposition associated with F600 application was 7.95 tons ha?1 year?1, equaling 121% of F400 and 160% of the control. Mortality in F600 was 8.75 tons ha?1 year?1, equaling 111% of F400 and 198% of F0, while production in F600 was 10.40 tons ha?1 year?1, equaling 127% of F400 and 143% of F0. Fineroot production, mortality, and decomposition are seasonally dependent, with higher values measured in the rainy season than in the dry season. Stand basal area increment was significantly correlated with fineroot production (R2?=?0.75), mortality (R2?=?0.44), and decomposition (R2?=?0.48). This study showed that fertilization could facilitate fineroot production, which can then lead to a higher turnover of carbon and nutrients through the decomposition of the greater mass of the fineroots.

  相似文献   
37.
    
Abstract. The aim of this study was to investigate the effects of water submergence depth on radial oxygen loss (ROL), soil solution chemistry and rice growth performance in acid sulphate soils in southern Vietnam. ROL was measured in a solution culture. In a separate pot experiment the impact of water submergence depth on rice growth and soil solution chemistry was studied. Three submergence depths were used in the two experiments (5, 10 and 15 cm). ROL declined with submergence depth and was significantly greater in young roots (with no root hairs) than in older roots. In the pot experiment rice growth and soil solution chemistry were clearly affected by the submergence depth. During the first crop at 5 cm submergence, there was a significantly higher yield and a higher oxidation state (pe+pH) compared to 10 or 15 cm submergence. The Fe concentration was significantly greater at the 5 cm depth compared to the 10 or 15 cm depth. SO42– reduction was delayed at the 5 cm depth. Rice yield was c. 25% less at the 15 cm than at the 5 cm depth. During a second crop, there was a substantial SO42- reduction and H2S formation and almost no significant effects of submergence depth on either soil solution chemistry or crop yield. In a field experiment with a dry-season rice crop, yield and Fe, Al and SO42– concentrations were higher at a shallow submergence depth than at greater depths in the same field, showing similar depth trends to those found during the first crop in the pot experiment. Farmers should be advised to use a shallow submergence depth and, if possible, avoid deep-rooted rice varieties. A conceptual model is suggested, which summarizes the relationships between ROL and soil solution chemistry.  相似文献   
38.
    
Fisheries managers are in need of quantitative tools to inform decisions regarding selection of robust management practices, prioritising research gaps and stocks to focus on, particularly where there are limited resources or data. To support these decisions, the use of Management Strategy Evaluation (MSE), that is, closed loop simulation-testing of management procedures, is widely regarded as best practice. However, applying MSE is time- and computationally intensive, and requires highly skilled expertise and processes for stakeholder input and peer review. For data- and capacity-limited fisheries, MSE may be particularly challenging to implement. Yet, these are the contexts where it is most critical to test assumptions, evaluate the implications of all sources of uncertainty and identify the most informative data sources. To facilitate wider use of MSE, the Method Evaluation and Risk Assessment (MERA) framework was developed as an accessible online interface, with quick processing time, focused on generic data-limited management procedures, but allowing progression to tailored and more data-rich methods. The framework links a quantitative questionnaire and data input standard to a flexible operating model with optional customisation via command line access to the back-end open-source R libraries. Here, we illustrate a case study application of MERA for the bocinegro (Pagrus pagrus, Sparidae) fishery in the Gulf of Cadiz, where in conjunction with fishery stakeholders, a custom management procedure was developed and tested and key research gaps and data collection priorities were identified. We discuss implications for wider use of MSE in various contexts, including eco-certification and fishery improvement projects.  相似文献   
39.
Dengue fever is an important mosquito-borne viral disease in Taiwan. Insecticide resistance has been shown to significantly reduce the efficacy of vector control interventions. The detection of insecticide resistance is an important component in mosquito abatement programs. In this study, we used the insecticide-impregnated papers bioassay method to reveal high levels of resistance to permethrin in the LYPR and field strains of Aedes aegypti. We used the standard glass cylinder method to observe the knockdown effect of paralysis within 2 to 4 minutes after exposing mosquitoes to pyrethroid vapors. Biochemical assays showed elevated detoxification enzyme activities. Glutathione S-transferases, monooxygenases and β-esterases were the enzymes predominantly responsible for the permethrin resistance of Ae. aegypti in Taiwan. Molecular screening for common insecticide target-site mutations revealed the presence of V1023G and D1794Y mutations. Pearson’s correlation analysis was used to investigate the correlations between the allelic frequency of kdr mutation associated increase with the LC50 values of permethrin and the KT50 values of pyrethroid vaporizers. These findings will be used to assess resistance levels, estimate resistance potential, and formulate monitoring and resistance management strategies.  相似文献   
40.
为了研究不同氮钾肥施用量对超级稻生理特性的影响,为超级稻氮钾肥综合运筹提供理论依据,以超级杂交稻‘桂两优2号’为材料进行大田试验,设置3个施氮水平(172.5、207、241.5kg/hm2)和3个施钾水平(216、288、360kg/hm2),以不施氮钾肥的处理(N0K0)作为对照,研究不同氮钾肥用量对‘桂两优2号’叶片叶绿素含量、硝酸还原酶活性、可溶性蛋白含量和谷氨酰胺合成酶活性及产量的影响。结果表明,研究结果表明,所选田块的基础地力产量(N0K0处理)较高,产量达到7.99t/hm2。施用氮钾肥显著提高了各生育期‘桂两优2号’叶片的叶绿素含量(6.44%~37.27%)、硝酸还原酶活性(19.33%~107.19%)、可溶性蛋白含量(10.90%~36.43%)和谷氨酰胺合成酶活性(14.25%~76.99%),进而获得了更高的产量(9.39~10.63t/hm2),但不同施氮量和施钾量间的差异并不显著。在基础地力产量与本试验田相当的田块,超级杂交稻‘桂两优2号’的生理特性对氮肥和钾肥施用量的敏感程度较低,氮钾肥施用量超过172.5kg/hm2和216kg/hm2,增施氮钾肥并不能显著改善其生理特性。  相似文献   
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