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991.
柴军 《新疆农业大学学报》1995,(3)
在多种关于总要素生产率动态值的计算方法中,本文赞同指数法,并认为这种方法是在利用劳动报酬作为劳动投入量的测度之后最简单而又具有可操作性的方法。在此基础上,本文将总要素生产率的变化分解为要素效率与结构效率两部分。 相似文献
992.
Pedro A. Salgueiro António Mira João E. Rabaça Carmo Silva Sofia Eufrázio Denis Medinas Giovanni Manghi Bruno Silva Sara M. Santos 《Landscape Ecology》2018,33(3):353-370
Context
When modeling a species’ distribution, landscapes can alternatively be conceptualized following patch- or gradient-based approaches. However, choosing the most suitable conceptualization is difficult and methods for empirical validation are still lacking.Objectives
To address the conditions under which a given conceptual model is more suitable, taking into account landscape context and species trait dependency effects. Patch- and gradient-based conceptualizations were built based on two structurally different landscapes: variegated and mosaic. We hypothesize that: (H1) gradient-based models better describe variegated landscapes while patch-based models perform better in mosaic landscapes; and (H2) gradient-based models will fit generalist species better while patch-based models will suit specialists better.Methods
We modeled the distribution of eleven bird species in each landscape using each conceptualization. We determined the suitability of each conceptual model to fit statistical models by looking for cross-species responses and deviations from best models.Results
We found no clear support for our hypotheses. Although patch-based models performed better in mosaic landscapes (H1), they also provided useful conceptualizations in variegated landscapes. However, when patches showed high heterogeneity, gradient-based approaches better fit specialist species (H2).Conclusions
The suitability of a given conceptual model depends on the interaction between species habitat specialization, and the intrinsic spatial heterogeneity of the landscape and the ability of each conceptualization to capture it. Gradient-based models provide better information on resource allocation, while patch-based models offer a simplified perspective on landscape attributes. Future research should consider the nature of both species and landscapes in order to avoid bias from inadequate landscape conceptualizations.993.
Sylvain Poggi Julien Papaïx Claire Lavigne Frédérique Angevin Florence Le Ber Nicolas Parisey Benoît Ricci Fabrice Vinatier Julie Wohlfahrt 《Landscape Ecology》2018,33(10):1679-1690
Context
Agroecosystems produce food and many other services that are crucial for human well-being. Given the scales at which the processes underlying these services take place, agricultural landscapes appear as appropriate spatial units for their evaluation and management. The design of sustainable agricultural landscapes that value these services has thus become a pressing issue but faces major challenges stemming from the diversity of processes, their interactions and the number of scales at stake. Agricultural landscape modelling can provide a key contribution to this design but must still overcome several difficulties to offer reliable tools for decision makers.Objectives
Our study aimed at shedding light on the main scientific and technical difficulties that make the building of landscape models that may efficiently inform decision-makers a complex task, as well as translating them in terms of challenges that can be further investigated and discussed.Methods
We examine current issues and challenges and indicate future research needs to overcome the scientific and technical obstacles in the development of useful agricultural landscape models.Results
We highlight research perspectives to better couple landscape patterns and process models and account for feedbacks, integrate the decisions of multiple stakeholders, consider the spatial and temporal heterogeneity of data and processes, explore alternative landscape organisations and assess multiobjective performance.Conclusion
Coping with the issues and challenges discussed in this paper should improve our understanding of agroecosystems and give rise to new hypotheses, thereby informing future research.994.
Faccio-Demarco Claudia Mumbach Tatiele Oliveira-de-Freitas Vanessa Fraga e Silva-Raimondo Raquel Medeiros-Gonçalves Fernanda Nunes-Corrêa Marcio Burkert-Del Pino Francisco Augusto Mendonça-Nunes-Ribeiro Filho Henrique Cassal-Brauner Cássio 《Tropical animal health and production》2019,51(8):2193-2201
Tropical Animal Health and Production - The aim of the current study was to assess the effect that supplementation with yeast culture plus enzymatically hydrolyzed yeast (YC-EHY) during the... 相似文献
995.
Costa Evely Giovanna Leite da Silva Fabiano Ferreira Silva Robério Rodrigues Porto Antonio Ferraz Santiago Bismarck Moreira Rocha Leone Campos Cruz Aline Gonçalves Guedes Anna Caroline Ferreira Neto Teotônio Martins Vieira Edvaldo Alves 《Tropical animal health and production》2019,51(8):2505-2511
Tropical Animal Health and Production - The objective of this study was to evaluate the inclusion of increasing levels of licuri meal as a substitute for soybean bran in the diet of pasture-based... 相似文献
996.
A number of commercially available disinfectants are commonly used on pig breeding farms and are authorised by the French Agricultural Ministry. However, the efficacy of these disinfectants is unknown with regard to the emergent porcine circovirus type 2 (PCV2). The virucidal efficacy of nine disinfectants was evaluated by testing a suspension of PCV2 isolated in France. The assays were performed at 20 degrees C and the efficacy determined after 30 min contact time between virus and disinfectant. After this time, the mixture was passed through a detoxification column and then diluted to remove compounds toxic to the virus and the porcine kidney cell line. The filtrate was serially diluted and inoculated onto cell culture. The infectivity of PCV2 was determined by an immunoperoxidase monolayer assay. No reduction in PCV2 titre was demonstrated with iodine and phenolic products. Significant PCV2 titre reductions (1.61 log(10)) were noted for the seven other products. For five disinfectants, namely a product composed of potassium monopersulfate, two products comprising a quaternary ammonium with one or three aldehyde(s), sodium hypochlorite, and sodium hydroxide, the concentration that significantly reduced the PCV2 titre was equal or 1.5-4 times lower than the authorised use concentration. Only two disinfectants, one composed of potassium monopersulfate, the other containing peracetic acid with hydrogen peroxide, reduced the PCV2 titre with a product concentration at best equal or two times higher than the authorised use concentration. 相似文献
997.
为建立阿卡斑病毒抗体检测方法,本研究以纯化的阿卡斑病毒作为包被抗原,以制备的抗阿卡斑病毒的多克隆抗体与待检血清竞争结合抗原,采用方阵滴定法优化反应条件,建立了阿卡斑病毒竞争ELISA(cELISA)抗体检测方法。通过对60份牛、羊阿卡斑病毒抗体阳性血清和40份阴性血清样品的检测,确定阴阳性样品抑制率(PI)临界值为60%;特异性试验结果显示,该方法对BTV-1、BTV-4、BTV-9、BTV-16、小反刍兽疫、中山病病毒、鹿流行性出血热病毒(EHDV)、羊痘和O型、A型、Asia-1型口蹄疫病毒阳性血清无交叉反应;敏感性试验结果显示,标准阳性血清1颐128倍稀释时,检测结果仍为阳性,SNT最低检出为,敏感性高于微量血清中和试验(SNT)检测结果(1颐64);批内和批间变异系数(CV)在0.54%~5.27%和0.3%~9.3%之间,具有较好的可重复性;用该方法与法国IDVET公司的同类试剂盒对85份牛、羊血清样品同时检测,结果显示二者符合率为91.76%,可以替代进口同类产品。本研究建立的检测方法特异性强、敏感性高、重复性好,可以用于阿卡斑病毒抗体检测和流行病学调查。 相似文献
998.
Fuminori Tanihara Maki Hirata Nhien T. Nguyen Quynh A. Le Takayuki Hirano Tatsuya Takemoto Michiko Nakai Dai‐ichiro Fuchimoto Takeshige Otoi 《Animal Science Journal》2019,90(1):55-61
Recently, we established the GEEP (“gene editing by electroporation of Cas9 protein”) method, in which the CRISPR/Cas9 system, consisting of a Cas9 protein and single guide RNA (sgRNA), is introduced into pig zygotes by electroporation and thus induces highly efficient targeted gene disruption. In this study, we examined the effects of sgRNA on the blastocyst formation of porcine embryos and evaluated their genome‐editing efficiency. To produce an animal model for diabetes, we targeted PDX‐1 (pancreas duodenum homeobox 1), a gene that is crucial for pancreas development during the fetal period and whose monoallelic disruption impairs insulin secretion. First, Cas9 protein with different sgRNAs that targeted distinct sites in the PDX‐1 exon 1 was introduced into in vitro‐fertilized zygotes by the GEEP method. Of the six sgRNAs tested, three sgRNAs (sgRNA1, 2, and 3) successfully modified PDX‐1 gene. The blastocyst formation rate of zygotes edited with sgRNA3 was significantly (p < 0.05) lower than that of control zygotes without the electroporation treatment. Our study indicates that the GEEP method can be successfully used to generate PDX‐1 mutant blastocysts, but the development and the efficiency of editing the genome of zygotes may be affected by the sgRNA used for CRISPR/Cas9 system. 相似文献
999.
Fuminori Tanihara Maki Hirata Satoru Iizuka Shinya Sairiki Masahiro Nii Nhien Thi Nguyen Quynh Anh Le Takayuki Hirano Takeshige Otoi 《Animal Science Journal》2019,90(6):712-718
The aim of this study was to investigate the ovarian follicular development, developmental competence of oocytes, and plasma anti‐Müllerian hormone (AMH) levels of Japanese wild boar crossbred (wild hybrid) gilts, whose litter size is inferior to that of European breeds. Ovary and plasma samples were collected from two different breeds of gilts (wild hybrid and Large White breeds). The ovaries from the wild hybrid gilts had a lower average numbers of secondary follicles and vesicular follicles in ovarian cross‐sections and of good quality oocytes collected from ovarian follicles as compared with those from Large White gilts (p < 0.05). The development rate to the blastocyst stage of good quality oocytes after in vitro maturation, fertilization and culture was also lower (p < 0.05) in wild hybrid gilts than in Large White gilts. Plasma AMH levels with >0.16 ng/ml were detected in 8.3% of the examined wild hybrid gilts and 33% of the Large White gilts. These results indicate that the low reproductive performance of wild hybrid breed may result in part from low numbers of vesicular follicles and good quality oocytes, and low developmental competence of oocytes. Moreover, plasma AMH levels may support low number of vesicular follicles in ovaries of wild hybrid gilts. 相似文献
1000.
The effects of muscarinic agonists on acetylcholine (ACh) release in the cercal-afferent giant-interneuron synapses of the cockroach have been studied using the single-fibre oil-gap method. Decrease in amplitude of the cEPSP was induced by pressure ejection of arecoline (ARE), carbachol (CCh) and oxotremorine free base (OXO) within the sixth abdominal (A6) ganglion. This depressive effect was dose-dependent without any effect at the post-synaptic site in the range of concentrations used. The concentration for 50% of cEPSP inhibition of the most commonly used muscarinic agonists was determined. The rank order of potencies was: ARE > CCh > OXO > McN-A-343 > bethanechol (BET). Plateau levels of 56%, 54% and 68% were reached when increasing the concentration of ARE, CCh and OXO respectively. McN-A-343 and BET had an inhibitory effect on ACh release but higher doses also acted at the postsynaptic level. Furthermore, muscarinic agonists were able to evoke uIPSP and a smaller inhibitory effect of ARE and OXO was observed in presence of picrotoxin. It is concluded that the ACh release in the cockroach A6 ganglion is modulated by presynaptic muscarinic receptors which are possible target sites for insecticides. The presence of putative muscarinic receptors on inhibitory GABAergic interneurons, involved in pre- and postsynaptic inhibition is suspected. 相似文献