首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 31 毫秒
1.
本研究利用Incofish项目开发的可持续发展指标开展渔业资源评估应用研究.研究对象为金色小沙丁鱼(Sardinella aurita)和短体小沙丁鱼(Sardinella maderensis).数据来源于1990年-2005年间塞内加尔个体渔业渔获量及由DR FRIDTJOF NANSEN调查船在塞内加尔海域获得的渔获量.采用Froese(2004年)提出的三个可持续捕捞指标,为渔业资源量的开发状况作出诊断和评估.这些指标包括:渔获物中成鱼的百分比（以100%为最佳）、达到最适开捕体长鱼的百分比（以100%为最佳）和大型产卵鱼的百分比（以0%为最佳,体长大于最适开捕体长1.1倍的雌鱼即为大型产卵鱼）.分析结果表明:金色小沙丁鱼处于过度捕捞状态,幼鱼在其渔获物中占有优势地位,捕捞到的金色小沙丁鱼多数小于最适开捕体长,即生长型过度捕捞;短体小沙丁鱼处于充分开发利用状态.总体结果揭示,可持续捕捞指标能够成为替代或完善传统资源评估方法的有用工具.渔业相关的利益主体（包括公众）通过这些指标能够避免过度捕捞,从而更好地理解渔业管理.  相似文献   

2.
《Research Policy》2023,52(9):104864
As an industry based upon the harvesting of wild resources, the fishery is often used in economics to showcase the effects of its specific nature on human behavior and the impacts of that behavior on the fish stock itself. The common-pool status usually encountered in the use of these resources makes them especially vulnerable to major shifts in the supporting ecosystems, but also to rapid technical change. In most other parts of the economy, technical change and the creative destruction that it brings along are viewed positively, and even given central role in recent theories of growth. Happily for the creatures of the ocean that are hunted, fishers do not fit the mould of Schumpetarian entrepreneurs bent on creative destruction. However, the technology that does drift onto boats has had concerning effects on the status of fish stocks with important economic and cultural consequences. We present a narrative of the French sardine fishery using the evolutionary theory of technical change. The wild binary segmentation approach was applied on a time-series of French sardine landings from 1900 to 2017. This analysis revealed three significant production change points associated with important technical changes in the fishery. The first change point, in 1927, is related to the introduction of the purse-seine in France. The introduction of the mid-water trawl is the second change point in the early 1970s. A third change point occurred in 1998, where we see a reswitch from mid-water trawl to purse-seine. Collectively, these results highlight the technological changes in sardine production that occurred, but more importantly, the impacts of these changes both on the structure of the population of sardines, and on the industry. The lesson we derive from this case study is that technical change should be considered as a succession of shifts rather than a unidirectional history.  相似文献   

3.
One of the benefits claimed for investment in Research and Development (R&D) is that there is a spillover effect. Industries benefit from both their own R&D efforts as well as the efforts of other national and overseas industries. The present research presents new evidence on the long-term impact of R&D investment upon UK industry's productivity performance and on the nature of these “R&D spillovers”. The results suggest that R&D efforts from the industry itself and from other national industries have a positive impact on the industry's productivity but, interestingly, there is no gain from foreign R&D investment.  相似文献   

4.
  相似文献   

5.
In this paper, we distinguish between firm-level learning effects that result from ‘first-order’ and ‘second-order’ additionalities in innovation policy interventions. ‘First-order’ additionalities represent direct firm-level R&D subsidies, whereas ‘second-order’ additionalities result from knowledge spill-overs, horizontal knowledge exchanges between firms, and from other meso- or community-level effects. Analyzing data from collaborative R&D programs in Finland, we show that enhancing identification with a community of practice among R&D program participants (proxy for second-order additionality) enhances firm-level learning outcomes beyond those resulting from direct R&D subsidy (proxy for first-order additionality). Learning effects facilitated by second-order additionality are not confined to technological learning alone, encompassing also business and market learning. We also show that aspects of program implementation enhance identification with a community of practice, which then mediate the relationship between program implementation and firm-level learning outcomes.  相似文献   

6.
本研究从比较三白草科属间小花个体发育及分析花器官数量变异入手，探寻花器官在发生顺序、数目变化及排列方式等方面的演化趋势，揭示系统发育在个体发育中一定程度重现的事实及属间的进化关系。结果简述如下：首先，雄蕊和心皮发生顺序由中部优先演化到两侧优先。其次，由于远中雄蕊和心皮经历了从发育延迟、生长减缓到最终消失的历程，中部雄蕊和心皮由成对演化为单生。此外，两侧生雄蕊对由各自独立的原基发生演化到共同原基发生或减化为1枚，假银莲花属近中1枚雄蕊原基二裂成1对，蕺菜属3枚心皮发生于一环状共同原基等，都是该科花器官演化的重要事实并可归结为融合、减化和复化的结果。文章根据花器官的演化趋势及过渡类型的剖析，论述了三白草科属间的系统进化关系。  相似文献   

7.
This award recognizes two specific discoveries that constitute the experimental discovery of neutrino oscillations. In 1998 the Super-Kamiokande group under the leadership of Yoji Totsuka published their paper, “Evidence for Oscillation of Atmospheric Neutrinos” in Physical Review Letters [1]. The paper describes a deficit of muon-type neutrinos from below the detector relative to those from above. It explains this “atmospheric neutrino anomaly” as a result of transformation of some of the muon neutrinos into another type of neutrino. Four years later, the group led by Arthur McDonald described “Direct Evidence for Neutrino Flavor Transformation from Neutral-Current Interactions in the Sudbury Neutrino Observatory” [2] in the same journal. This experiment detected lower energy neutrinos from deep inside the Sun. By measuring all flavors of neutrinos with large rates, the SNO collaboration showed definitively that the long-standing “solar neutrino puzzle” was another manifestation of neutrino oscillations. As a result of these two experiments, we now understand that neutrinos can change identities during propagation and that both the solar and atmospheric neutrino “problems” result from the same underlying phenomenon of oscillations. A consequence of neutrino oscillations is that neutrinos, previously thought to be massless, must have a non-zero rest mass.  相似文献   

8.

Introduction

The aim of the study was to present a protocol for laboratory information system (LIS) and hospital information system (HIS) validation at the Institute of Clinical Chemistry and Laboratory Medicine of the Merkur University Hospital, Zagreb, Croatia.

Materials and methods:

Validity of data traceability was checked by entering all test requests for virtual patient into HIS/LIS and printing corresponding barcoded labels that provided laboratory analyzers with the information on requested tests. The original printouts of the test results from laboratory analyzer(s) were compared with the data obtained from LIS and entered into the provided template. Transfer of data from LIS to HIS was examined by requesting all tests in HIS and creating real data in a finding generated in LIS. Data obtained from LIS and HIS were entered into a corresponding template. The main outcome measure was the accuracy of transfer obtained from laboratory analyzers and results transferred from LIS and HIS expressed as percentage (%).

Results:

The accuracy of data transfer from laboratory analyzers to LIS was 99.5% and of that from LIS to HIS 100%.

Conclusion:

We presented our established validation protocol for laboratory information system and demonstrated that a system meets its intended purpose.  相似文献   

9.
BackgroundCollagen is the most abundant protein in animals and can be obtained from residues of the food industry. Its hydrolysate has many desirable properties that make it suitable as an additive in foods and cosmetics, or as a component of scaffold materials to be used in biomedicine.ResultsWe report here the characterization of type I collagen from five different sources, namely bovine, porcine, chicken, trout and salmon, as well as their hydrolysates by means of bioinformatics tools. As expected, the results showed that bovine and porcine collagen, as well as trout and salmon collagen, can be used interchangeably due to their high identity. This result is consistent with the evolution of proteins with highly identical sequences between related species. Also, 156 sequences were found as potential bioactive peptides, 126 from propeptide region and 30 from the central domain, according to the comparison with reported active sequences.ConclusionsCollagen analysis from a bioinformatic approach allowed us to classify collagen from 5 different animal sources, to establish its interchangeability as potential additive in diverse fields and also to determine the content of bioactive peptides from its in silico hydrolysis.How to citeNuñez SM, Guzmán F, Valencia P, et al. Collagen as a source of bioactive peptides: a bioinformatics approach. Electron J Biotechnol 2020; 48. https://doi.org/10.1016/j.ejbt.2020.09.009.  相似文献   

10.
We explore the impact of geographic dispersion of a firm's R&D activities on the quality of its innovative output. Using data on over half a million patents from 1127 firms, we find that having geographically distributed R&D per se does not improve the quality of a firm's innovations. In fact, distributed R&D appears to be negatively associated with average value of innovations. This suggests that potential gains from access to diverse ideas and expertise from different locations are, on average, offset by difficulty in achieving integration of knowledge across multiple locations. To investigate whether the innovating teams that do manage cross-fertilization of ideas from different locations achieve more valuable innovations, we analyze innovations for which there is evidence of such knowledge cross-fertilization along any of the followings dimensions: knowledge sourcing from other locations within the firm, having at least one inventor with cross-regional ties, and having at least one inventor that has recently moved from another region. Analysis along all three dimensions consistently reveals a direct positive effect cross-regional knowledge integration has on innovation quality, as well as a positive interaction effect of cross-regional knowledge integration and distributed R&D for innovation quality. More generally, our findings provide new evidence regarding the importance of cross-unit integrative mechanisms for achieving superior performance in multi-unit firms.  相似文献   

11.
BackgroundCoconut tissues consist of a complex network of polysaccharides, proteins, polyphenols, and lipids that can bind to nucleic acids and pose difficulty in isolation. Certainly, a vigorous method is required to isolate high quality and quantity of RNA from such tissues for the purpose of downstream experiments. In this paper, we discuss a newly developed method for the Isolation of RNA from Complex Matrices (IRCM) method from coconut tissues.ResultsThe method is robust, cheap, and efficient for the extraction of quality RNA in high quantities from the solid endosperm of stored and fresh coconut (150 μg/g FW with A260/280 = 1.89 and 247.5 μg/g FW with A260/280 = 1.91), coconut apple (263.8 μg/g FW with A260/280 = 1.97), and coconut bud (1052.5 μg/g FW with A260/280 = 2.00). The other well established methods, such as Method of RNA Isolation from Palm (MRIP), Cetyl Trimethyl Ammonium Bromide (CTAB), TRIZOL, and RNA plant kit failed to isolate quality RNA in appreciable quantities from the coconut tissues. Furthermore, the resultant RNA performed well in the downstream experiment, that is, RT-PCR for the production and amplification of cDNA.ConclusionsFrom the study, we concluded that the present method will play a vital role in the extraction of high quality RNA from complex matrices in a short time.How to cite: Iqbal A, Yang Y, Wu Y, et al. An easy and robust method for the isolation of high quality RNA from coconut tissues. Electron J Biotechnol 2020;48. https://doi.org/10.1016/j.ejbt.2020.09.008  相似文献   

12.
BackgroundThe bioethanol produced from biomass is a promising alternative fuel. The lignocellulose from marginal areas or wasteland could be a promising raw material for bioethanol production because it is present in large quantities, is cheap, renewable and has favorable environmental properties. Despite these advantages, lignocellulosic biomass is much more difficult to process than cereal grains, due to the need for intensive pretreatment and relatively large amounts of cellulases for efficient hydrolysis. Therefore, there is a need to develop an efficient and cost-effective method for the degradation and fermentation of lignocellulosic biomass to ethanol.ResultsThe usefulness of lignocellulosic biomass from wasteland for the production of bioethanol using pretreatment with the aid of ionic liquids of 1-ethyl-3-methylimidazolium acetate and 1-ethyl-3-methylimidazolium chloride was evaluated in this study. The pretreatment process, enzymatic hydrolysis and alcoholic fermentation lasted a total of 10 d. The largest amounts of bioethanol were obtained from biomass originating from agricultural wasteland, in which the dominant plant was fireweed (Chamaenerion angustifolium) and from the field where the common broom (Cytisus scoparius) was the dominant.ConclusionsThe plants such as fireweed, common broom, hay and goldenrod may be useful for the production of liquid biofuels and it would be necessary in the further stage of research to establish and optimize the conditions for the technology of ethyl alcohol producing from these plant species. Enzymatic hydrolysis of biomass from agricultural wastelands results in a large increase in fermentable sugars, comparable to the enzymatic hydrolysis of rye, wheat, rice or maize straw.How to cite: Smuga-Kogut M, Piskier T, Walendzik B, et al. Assessment of wasteland derived biomass for bioethanol production. Electron J Biotechnol 2019;41. https://doi.org/10.1016/j.ejbt.2019.05.001.  相似文献   

13.
论循环经济的本质与政策启示   总被引：2，自引：1，他引：1  
循环经济是全面模仿自然生态系统的物质循环机制和能量梯级利用规律而重构经济系统,使经济活动的环境影响和寿命周期成本最小化、价值最大化,从而以最低的资源和环境代价实现经济与环境协调发展的技术经济模式。分别从资源经济学、环境经济学、生态学、系统论、经济学、价值工程、哲学和技术进步等角度来看,循环经济都表现出一定的特质,从而使其在本质上成为:(1)以资源循环利用为核心的自循环经济;(2)环境友好型经济;(3)全生态仿生经济;(4)良性超非线性经济;(5)实现技术资源、自然资源与环境资源综合优化配置的可持续性经济;(6)全功能、低周期寿命成本(高价值)经济;(7)方法论经济;(8)消除技术进步非对称性的理想路径,人类技术经济思维方式革命、技术经济范式革命和环境保护范式革命。对于循环经济本质的认识能够使我们获得许多有益的政策启示。  相似文献   

14.
IntroductionIt is common for patients to switch between several healthcare providers. In this context, the long-term follow-up of medical conditions based on laboratory test results obtained from different laboratories is a challenge. The measurement uncertainty in an inter-laboratory context should also be considered in data mining research based on routine results from randomly selected laboratories. As a proof-of-concept study, we aimed at estimating the inter-laboratory reference change value (IL-RCV) for exemplary analytes from publicly available data on external quality assessment (EQA) and biological variation.Materials and methodsExternal quality assessment data of the Reference Institute for Bioanalytics (RfB, Bonn, Germany) for serum creatinine, calcium, aldosterone, PSA, and of whole blood HbA1c from campaigns sent out in 2019 were analysed. The median CVs of all EQA participants were calculated based on 8 samples from 4 EQA campaigns per analyte. Using intra-individual biological variation data from the EFLM database, positive and negative IL-RCV were estimated with a formula based on log transformation under the assumption that the analytes under examination have a skewed distribution.ResultsWe estimated IL-RCVs for all exemplary analytes, ranging from 13.3% to 203% for the positive IL-RCV and - 11.8% to - 67.0% for the negative IL-RCV (serum calcium - serum aldosterone), respectively.ConclusionExternal quality assessment data together with data on the biological variation – both freely available – allow the estimation of inter-laboratory RCVs. These differ substantially between different analytes and can help to assess the boundaries of interoperability in laboratory medicine.  相似文献   

15.
Using a composite sample of over 3600 index terms drawn from 11 different machine-readable bibliographic data bases, estimates were made of the spelling error frequencies of each of these data bases, as well as the frequency of posting to misspelled terms. The terms studied included assigned index terms as well as some terms from titles and abstracts. The frequency of index term misspellings ranged from a high of almost 23% for one data base to a low of less than 12% for another data base. The frequency of posting to misspelled terms ranged from about one posting in 8000 citations for one data base, to about one posting in 160 citations in another data base. The impact of these error rates is discussed for the tape supplier, tape user and end user. Some suggestions are given regarding search strategry.  相似文献   

16.
《Endeavour》2020,44(1-2):100718
Charles Lyell's life work, the influential textbook and philosophical treatise The Principles of Geology, helped to shape the Victorian age. There were few diversions from the central task of the Principles of Geology in the course of the twelve editions. Perhaps the most significant and notable was the discovery and investigation of loess; a silty sediment, often of considerable thickness, and widely distributed in the Rhine valley. He made a significant contribution to loess studies and, with his father-in-law, Leonard Horner, explored the loess regions of the Rhine Valley. The loess period lasted roughly from 1830 to 1836, and he established the first paradigm theory for the formation of loess deposits from deposition in a lake or perhaps from slow-moving water. This held sway until displaced by the aeolian theory of F. von Richthofen.  相似文献   

17.
   The present paper is an attempt to make a taxonomic study of the little known orchid genus Holcoglossum, as well as a comparison of the genus with its allies, such as Vanda, Papilionanthe, Ascolabium, Ascocentrum, Aěrides, Neofinetia and Saccola- bium.      Holcoglossum was established by Schlechter in 1919 (Orchideologiae Sino-Japoni- cae Prodromus) as a monotypic genus, based upon Saccolabium quasipinifolium Hayata. Five years later he published another true Holcoglossum as Aěrides flavescens, which was referred by Tang et Wang to Saccolabium in 1951.  Further investigation of this genus was by Garay in 1972 who added two species, H. kimballiana and V. rupestris (synonymy of Aěrides flavescens), but considered Neofinetia, a quite different taxon, to be congeneric.  It is shown that the demarcation of Holcoglossum remains cofused. During the course of our study, the species of Holcoglossum and its allied genera are carefully examined, we come to the conclusion that Ho lcoglossum is a distinct genus. It is characterized by the short stem; fleshy terete or subterete, sulcate above leaves, with their apex acute and non-lobed; thickening or keeled costa on the back of sepals, 3-lobed lip, with erect sidelobes, paralled to the column; slender and recurved spur; footless column usually with prominent wings; 2 notched pollinia attached to linear stipe which is tapered toward the base.  In addition to Ascolabium, it differs from Vanda, Papilionanthe, Ascocentrum, Aěrides, Neofinetia and Saccolabium by its terete or subterete leaves on their ventral side with a furrow, from Papilionanthe by lacking footless column, from Ascolabium by sepals and spur characters, from Ascocentrum by slender and recurred spur, from Aěrides by the absence of a column-foot and the appearance of spur, from Neofinetia by stipe tapered toward the base, from Saccolabi-um by both aspects of the vegetative organs and the flowers.  相似文献   

18.
The paradox of openness: Appropriability,external search and collaboration   总被引：1，自引：0，他引：1  
To innovate, firms often need to draw from, and collaborate with, a large number of actors from outside their organization. At the same time, firms need also to be focused on capturing the returns from their innovative ideas. This gives rise to a paradox of openness—the creation of innovations often requires openness, but the commercialization of innovations requires protection. Based on econometric analysis of data from a UK innovation survey, we find a concave relationship between firms’ breadth of external search and formal collaboration for innovation, and the strength of the firms’ appropriability strategies. We show that this concave relationship is stronger for breadth of formal collaboration than for external search. There is also partial evidence suggesting that the relationship is less pronounced for both external search and formal collaboration if firms do not draw ideas from or collaborate with competitors. We explore the implications of these findings for the literature on open innovation and innovation strategy.  相似文献   

19.
A wide range of diseases and conditions are monitored or diagnosed from blood plasma, but the ability to analyze a whole blood sample with the requirements for a point-of-care device, such as robustness, user-friendliness, and simple handling, remains unmet. Microfluidics technology offers the possibility not only to work fresh thumb-pricked whole blood but also to maximize the amount of the obtained plasma from the initial sample and therefore the possibility to implement multiple tests in a single cartridge. The microfluidic design presented in this paper is a combination of cross-flow filtration with a reversible electroosmotic flow that prevents clogging at the filter entrance and maximizes the amount of separated plasma. The main advantage of this design is its efficiency, since from a small amount of sample (a single droplet  ～ 10 μl) almost 10% of this (approx 1 μl) is extracted and collected with high purity (more than 99%) in a reasonable time (5–8 min). To validate the quality and quantity of the separated plasma and to show its potential as a clinical tool, the microfluidic chip has been combined with lateral flow immunochromatography technology to perform a qualitative detection of the thyroid-stimulating hormone and a blood panel for measuring cardiac Troponin and Creatine Kinase MB. The results from the microfluidic system are comparable to previous commercial lateral flow assays that required more sample for implementing fewer tests.  相似文献   

20.
This paper examines the various methods through which firms benefit from interactions with universities, arguing that such benefits are instrumental in nurturing the multiple facets of a firm's absorptive capacity. We bring together data collected from a survey of UK firms that collaborated with universities, and firm-level data on past partnerships with universities. The results show that benefits from interactions with universities are multifaceted, including enhancement of the firm's explorative and exploitative capabilities. Results also indicate that firms’ R&D commitments, geographical proximity to and research quality of university partners have a distinct impact on the different types of benefits from interactions with universities. We find geographical proximity is crucial for assessing problem-solving as an important benefit, while interactions with top quality universities have a positive influence on the benefits associated with firms’ downstream activities. We discuss the implications of these findings for research and policy.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号