Establishment of a microbiologically acceptable daily intake of antimicrobial drug residues     

C. J. van Nie 《The Veterinary quarterly》2013,33(3):152-160

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Formation of carbon–carbon composite using wood as a precursor     

《Wood material science & engineering》2013,8(2):152-158

Abstract

The use of wood as structure-giving material may be an effective approach to reduce some barriers for producing high temperature ceramic especially carbon composites. The objective of this study was to develop a simple process for producing carbon–carbon (C–C) composite through porous template result from pyrolysing of wood. Walnut, known to be relatively permeable, was being heat treated under controlled atmosphere. The carbon-template formed was infiltrated with coal tar pitch. Morphological characterization of the resulting composite was carried out by scanning electron microscopy morphology and physical properties of sample were evaluated with determination of bulk density and open porosity. In addition mechanical properties of products were analysed with three-point bending test and Vickers micro hardness. Results showed that bulk density had an uprising trend with increasing the number of densification cycles and subsequently open porosity decreased. Moreover, from mechanical property's point of view, results had a good compatibility with increase in the densification cycles.  相似文献   

Development of site index curves for Pinus kesiya in the Philippines     

《Southern Forests》2013,75(2):115-120

This study was conducted to develop a height–age growth model and site index curves for site quality evaluation of old secondary-growth stands of Pinus kesiya in the northern Philippines. The Chapman-Richards growth function was used in the guide curve method to generate anamorphic site index curves for this species. In order to evaluate the developed model, coefficient of determination (R ² ), root mean square error (RMSE), bias (ē), absolute mean difference (AMD) and mean percent bias (MPB) were used as statistical criteria. The Chapman-Richards model explained about 96.84% of the total variation of the dominant height. The value of ē was ?0.004 m, AMD was 2.566 m, MPB was 3.88% and RMSE was 3.331. The site index curves developed as a result of this study are significant for forest managers in predicting the growth patterns and classification of site productivities for Pinus kesiya stands.  相似文献   

不同寄主植物对小菜蛾生长发育和繁殖的影响     

李引  冷春蒙  胡迪  仵均祥  李怡萍 《西北农业学报》2019,28(3):475-480

小菜蛾(Plutella xylostella L.)是世界范围内十字花科植物的头号害虫,试验在26℃、光照明暗比为16L∶8D、湿度为70%的条件下,以甘蓝(Brassica oleracea L.)(‘秦甘70’‘秦甘80’‘绿球66’)、小青菜(Brassica chinensis L.)(‘上海四月慢’)、花椰菜(Brassica oleracea L.var.botrytis)(‘荷兰83号’)和油菜(Brassica napus L.)(‘青杂7号’)6个不同品种4类十字花科蔬菜为食料,观察小菜蛾一个完整世代的不同生命参数,并分析取食不同十字花科寄主的小菜蛾生长发育状况及繁殖差异。结果表明:在6个不同品种4类十字花科中,取食‘荷兰83号’花椰菜的小菜蛾试验组幼虫历期、蛹历期、蛹质量、卵历期及全世代历期最短,其全世代存活率最高;取食‘上海4月慢’小青菜的小菜蛾试验组幼虫存活率、化蛹率、蛹羽化率、卵孵化率及全世代存活率最低,其成虫历期、卵历期及全世代历期为最长。在4类十字花科寄主中,小菜蛾的最适寄主植物为‘荷兰83号’花椰菜,最不适宜小菜蛾生长发育及繁殖的为‘上海四月慢’小青菜。  相似文献   

Immediate and subsequent effects of drying and rewetting on microbial biomass in a paddy soil     

Kozue Sawada  Shinya Funakawa  Takashi Kosaki 《Soil Science and Plant Nutrition》2019,65(1):28-35

Many surface soils in Japan may experience more frequent and intense drying–rewetting (DRW) events due to future climate changes. Such DRW events negatively and positively affect microbial biomass carbon (MBC) through microbial stress and substrate supply mechanisms, respectively. To assess the MBC immediately after DRW and during the incubation with repeated DRW cycles, two laboratory experiments were conducted for a paddy soil. In the first experiment, we exposed the soil to different drying treatments and examined the MBC and hourly respiration rates immediately after the rewetting to evaluate the microbial stress. In the second experiment, we compared microbial growth rates during the incubation of the partially sterilized soil with a continuously moist condition and repeated DRW cycles to evaluate the contribution of the substrate supply from non-biomass soil organic C on MBC. First, all drying treatments caused a reduction in MBC immediately after the rewetting, and higher drying intensities induced higher reduction rates in MBC. A reduction of more than 20% in MBC induced the C-saturated conditions for surviving microbes because sufficient concentrations of labile substrate C were released from the dead MBC. Second, repeated DRW cycles caused increases in the microbial growth rates because substrate C was supplied from non-biomass organic C. In conclusion, MBC decreased immediately after DRW due to microbial stress, whereas MBC increased during repeated DRW cycles due to substrate C supplied from non-biomass organic C.  相似文献   

Proximate and mineral components of Viscum album var. coloratum grown on eight different host tree species     

Chul-Woo Kim  Chan-Hoon An  Hyun-Seok Lee  Jae-Seon Yi  Eun Ju Cheong  Sang-Hyun Lim  Hee-Yeon Kim 《林业研究》2019,(4):1245-1253

Mistletoes are parasite plants growing on various tree species,taking nutrients from the host.Beneficial compounds of mistletoe were used in medicine and these mistletoes were commonly collected from oak species that were not well identified.We analyzed the nutritional value by measuring proximate and mineral components of Korean mistletoe(Viscum album var.coloratum)from various host trees.Carbohydrate was the most proximate component in both leaves and twigs followed crude protein,crude fiber,crude ash and crude fat.While the contents of the proximate components and minerals varied among hosts and between plant parts,leaves contained higher crude protein and ash,and more minerals except for magnesium than twigs,although no significant difference was found inmistletoe grown on Prunus mandshurica.There were significant differences of proximate and mineral contents depending on the host species.Mistletoe grown on Chaenomeles sinensis contained higher levels of carbohydrates,crude fat,crude ash,magnesium,calcium,sodium,iron,and zinc than mistletoe grown on other species.Mistletoe grown on P.mandshurica contained high mineral levels of potassium,copper and phosphorous.The nutritional value of mistletoes were greatly influenced by the host species but among the hosts,specific nutrients accumulated in leaves more than in twigs,and vice versa.Based on the analysis,Korean mistletoe contains relatively good quality of nutrients and has high potential for dietary supplements as well as for medicinal compounds.  相似文献   

Climate change impacts and forest adaptation in the Asia–Pacific region: from regional experts' perspectives     

Guangyu Wang  Shari L.Mang  Brianne Riehl  Jieying Huang  Guibin Wang  Lianzhen Xu  Kebiao Huang  John Innes 《林业研究》2019,(1):277-293

Expert opinions have been used in a variety of fields to identify relevant issues and courses of action. This study surveys experts in forestry and climate change from the Asia–Pacific region to gauge their perspectives on the impacts of climate change and on the challenges faced by forest adaptation in the region, and explores recommendations and initiatives for adapting forests to climate change. There was consensus regarding the impacts of climate change on forest ecosystems and on economic sectors such as agriculture and forestry. Respondents also indicated a lack of public awareness and policy and legislation as challenges to addressing climate change. However, the results indicate differences in opinion between regions on the negative impacts of climate change and in satisfaction with actions taken to address climate change,highlighting the need for locally specific policies and research. The study presents specific recommendations to address issues of most concern, based on subregion and professional affiliation throughout the Asia–Pacific region.The results can be used to improve policy and forest management throughout the region. This research will also provide valuable suggestions on how to apply research findings and management recommendations outside of the AP region. The conclusions should be communicated relative to the level of the research and the target audience,ensuring that scientific findings and management recommendations are effectively communicated to ensure successful implementation of forest adaptation strategies.  相似文献   

Influence of summer legume residue recycling and varietal diversification on productivity,energetics, and nutrient dynamics in basmati rice–wheat cropping system of western Indo-Gangetic Plains     

Vijay Pooniya  R. S. Bana  K. Sawarnalaxmi  Pankaj  D. S. Rana 《Journal of plant nutrition》2018,41(12):1491-1506

A field experiment was conducted on summer mungbean residue recycling (SMBRR) and basmati rice–wheat cropping system (BRWCS) at New Delhi, India. The SMBRR enhanced the system productivity and net returns by ～19.1% and 22.1% compared to summer fallow (SF) with highest magnitude under genotypic sequence of P 2511/HD 2967. Two genotypes each in basmati rice (PB 1 and P 2511) and wheat (HD 2967 and HD 2733) responded well to SMBRR with respect to grain yield efficiency index (GYEI) ≥ 1.0. SMBRR also registered ～13.5% higher microbial biomass carbon (MBC) than SF. Soil organic carbon (SOC) storage also increased by ～6.8% in 0–30 cm soil layer. The rice–wheat–summer mungbean system produced significantly highest energy efficiency compared to the rice–wheat–summer fallow system with highest values under genotypic sequence of P 2511/HD 2967 as a result of better yield expression. Overall, SMBRR with suitable genotypic sequence improved the system productivity, profitability, and nutrient dynamics in BRWCS, which are vital for long-term sustainability of this system.  相似文献   

Rodent abundance triggered switch between the relative mutualism and predation in a rodent–seed system of the subtropical island forest     

Di ZENG  Tinghao JIN  Yuhao ZHAO  Chuan YAN  Zhibin ZHANG  Ping DING 《Integrative zoology》2021,16(1):109-119

Density-dependent non-monotonic species interactions are important in maintaining ecosystem stability and function, but empirical evidences are still rare. Rodents, as both seed dispersers and seed predators, have dual effects on plant regeneration and may result in non-monotonic rodent-plant interactions. According to the non-monotonic models, the relative positive or negative effects of rodents on seedling establishment can be measured based on the positive or negative association of seedling recruitment rate and rodent abundance. In this study, we investigated the fates of acorns of Quercus serrata by tracking tagged seeds on 21 fragmented subtropical islands in the Thousand Island Lake, China. We found that the proportion of germinated seeds of all released seeds showed a dome-shaped association with rodent abundance per seed. The proportion of removed seeds and cached seeds showed a saturated- and a weak dome-shaped association with rodent abundance per seed, respectively. Our results demonstrated a clear empirical evidence that rodent abundance per seed triggered a switch between the relative mutualism and predation in a rodent–seed system. Our study implied that the observed non-monotonic interactions between plants and animals may play a significant role in maintaining biodiversity and ecosystem function. We appeal for more investigations of the complex non-monotonic interactions in various ecosystems.  相似文献   

Growth and weed suppression ability of common and new cover crops in Germany     

《Crop Protection》2014

Cover crops have a wide-ranging influence on the agroecosystem and create multiple benefits for farmers. A major benefit of cover crops is the suppression of weeds during fall and winter, which can help to reduce soil tillage and herbicide use. However, only a small number of cover crop species are currently grown in Germany. To enlarge this number, four new cover crop species including tartary buckwheat, forage radish, red oat and grain amaranth were tested in comparison with common cover crop species such as white mustard, oilseed radish and phacelia. Emergence, soil coverage, dry matter production and weed suppression ability was assessed for all cover crop species. White mustard emerged faster than all other cover crops and produced the highest amount of shoot dry matter at both locations in southwest Germany twelve weeks after planting (WAP). Oilseed radish was the only cover crop that reduced the weed dry matter in all experiments eight WAP. Phacelia was able to reduce weed density by 77% at Meiereihof twelve WAP. Tartary buckwheat offered the highest soil coverage four WAP, produced the greatest shoot dry matter eight WAP and reduced weed dry matter by more than 96% at Meiereihof and Ihinger Hof twelve WAP. Forage radish produced the highest root dry matter and reduced spring weed density by more than 81% in all experiments. Red oat and grain amaranth emerged slowly, produced less biomass than other cover crops and did not suppress weed growth. The results show that tartary buckwheat and forage radish are well suited as new cover crops in Germany due to their fast growth and good weed suppression ability.  相似文献