发状念珠藻的分离纯化及人工培养条件研究

为探讨发状念珠藻的分离纯化与人工培养条件,以采自陇西县发状念珠藻原植体为实验材料,经分离纯化后考察培养基、温度、光照对发状念珠藻生长的影响。成功分离纯化发状念珠藻藻种,其分别在BG11、28℃以及50μmol·m^-2·s^-1培养条件得到最大生长速率。该研究结果为将来大规模人工培养发状念珠藻提供科学依据。     

Stratified studies about risk ratios in 2 × 2 tables with structural zero

Incomplete correlated 2 × 2 tables are common in some infectious disease studies and two‐step treatment studies in which one of the comparative measures of interest is the risk ratio (RR). This paper investigates the two‐stage tests of whether K RRs are homogeneous and whether the common RR equals a freewill constant. On the assumption that K RRs are equal, this paper proposes four asymptotic test statistics: the Wald‐type, the logarithmic‐transformation‐based, the score‐type and the likelihood ratio statistics to test whether the common RR equals a prespecified value. Sample size formulae based on hypothesis testing method and confidence interval method are proposed in the second stage of test. Simulation results show that sample sizes based on the score‐type test and the logarithmic‐transformation‐based test are more accurate to achieve the predesigned power than those based on the Wald‐type test. The score‐type test performs best of the four tests in terms of type I error rate. A real example is used to illustrate the proposed methods.     

中世纪欧洲大学“学者社团”之法理解析

大学起源于中世纪欧洲。起源时,其法律名称是"学者社团"。中世纪大学是学者的自治组织,具有法人资格和自治权。与其他社团如教会、城市和行会等相比较,中世纪大学具有成员是学者、目的是探索高深学问、内部构造是"联邦制"等特征。中世纪大学的法律地位与我国大学的法律地位不具有可比性。我国现行法律上与其最近似的是"社会团体法人"。     

When Power Hurts: Task‐dependent Resource Control Creates Temporary Discomfort that Motivates Helping Behaviour

This study investigated why workers in a position of power are motivated to help their dependent co‐workers. Previous research has assumed that powerful workers would experience increased behavioural approach and disinhibition, leading to selfishness and lower levels of help. However, this assumption fails to explain the helping behaviour often observed at work. In this study, 563 participants were placed in situations of power across three experiments, which measured helpfulness, discomfort, and behavioural approach and inhibition. The results suggest that power creates psychological discomfort, which mediates helping behaviour. Providing help reduced feelings of discomfort. This study helps reconcile previous mixed findings when applying power theories to work situations, and tested a new discomfort‐reduction explanation for helping behaviour. Copyright © 2018 ASAC. Published by John Wiley & Sons, Ltd.     

A Methodology for Farm-Level Economic Analysis of Soil Erosion Effects Under Alternative Crop Rotational Systems in Ontario

Multiperiod linear programming techniques are used to evaluate comparative profitabilities and soil erosion rates for corn grown monoculturally and in rotation with a) soybeans, b) soybeans and oats, c) barley, and d) alfalfa on moderately sloping land with medium loam soils in southern Ontario. Attention is focussed on the case of a highly leveraged recent entrant to farming with heavy debt servicing needs and potential cash flow constraints. Monocultural corn was found to be more profitable than any of the rotational systems, with corn-soybeans rotations the next most profitable and corn-barley rotations the least profitable. Corn-soybeans caused the highest soil erosion, followed by continuous corn, with corn-alfalfa rotations causing the least. Les techniques de programmation linéaire multipériode sont utilisées pour évaluer et comparer les niveaux de profit et les taux d' érosion de sols agricoles moyennement argileux pour des systèmes de production de grandees cultyres localiées dans le sud de l' ontario et produisant, soit du mais en régime de monoculture, soit du mais en rotation avec: a) du soja, b) soja et avoine, c) orge. et d) de la luzerne plantée sur des terrains à pentes modérées. L' analyse developpée dans cet article met l' accent sur des agriculteurs récemment installés, disposant de beaucoup d' actifs, mais également, ayant des besoins énormes d' emprunts et, par conséquent, soumis à des contraintes potentielles sur leurs cash-flows. Les résultats obtenus montrent que le système de production, mais-monoculture, est le plus viable de tous les systèmes etudies. Parmi les systemes de production reposant sur une rotation culturale, il s' avère que celui combinant maïs et soja vienne en seconde position, tandis que un régime cultural fondé sur une rotation maïs et orge donne les pires resultats. Pour ce qui concerne des taux d' erosion des sols, la rotation maïs-soja cause les plus gros dommages. ensuite suivie par le système de production, maïs-monoculture. Finalement, les taux d' erosion les plus faibles ont été obtenus pour la rotation culturale, maïs-luzerne.     

The Development of Agrarian Capitalism in Post‐Soviet Russia

A core set of criteria have been met, so that it is accurate to speak of an agrarian capitalist system in Russia. The development of agrarian capitalism carries with it increased stratification, which is analysed along five dimensions: earned income, land expansion, use of credit, income from food sales and income from household enterprise. The paper demonstrates increasing differentiation between households, between professional cohorts and within professional cohorts. The data showing stratification within professions suggest that intra‐cohort stratification is driving most of the inter‐cohort stratification. The Russian model of agrarian capitalism and its processes of stratification have yielded a bifurcated countryside in which a thin stratum of ‘super winners’ has emerged. Economic processes have developed beyond simple stratification and have created the basis from which a rudimentary class structure appears to be forming.     

Collaborating with Competitors: How Do Small Firm Accounting Associations and Networks Successfully Manage Coopetitive Tensions?*

The “coopetition” paradox exists when two or more organizations are simultaneously involved in cooperative and competitive interactions. In the accounting industry, small firms encounter coopetition when they align themselves with other independent firms to form accounting associations and networks (AANs). AANs are a type of interorganizational relationship (IOR) that provide opportunities for member firms to collaborate by sharing important resources such as expertise, best practices, and manpower. However, member firms also compete in the marketplace for clients and human capital, which incentivizes uncooperative and opportunistic behavior. If managed inadequately, coopetitive tensions can significantly hamper AAN benefits and may lead to IOR failure. Given the considerable longevity of AANs, we interview 42 high‐level accounting professionals to understand AANs' apparent successful management of these tensions. Leveraging coopetition and IOR theory, our analysis suggests that transactional mechanisms (contractual agreements, organizational structure, selection/monitoring processes) and relational mechanisms (trust, social ties, reciprocity) play key roles in encouraging healthy cooperation and competition among member firms. One of our main conclusions is that these mechanisms contribute to AAN success because they are leveraged comprehensively across each IOR life cycle phase, and they are mutually reinforcing, with transactional mechanisms providing the foundation to inspire confidence and encourage the development of relational mechanisms. Our research enriches existing accounting and coopetition literature, provides a new perspective for AANs, and responds to calls to understand key factors of IOR success.     

Consumer Welfare and the Livestock Economy in the United States

This paper analyzes the responsiveness of the U.S. meal and poultry economy to government policies and other exogenous shocks. In particular, it focuses on the measurement of changes to consumer welfare. An explicit econometric model represents the supply of fed beef, non-fed beef, pork, and poultry. The interaction between the livestock and feed grain markets is captured by an econometric model of the supply and demand for corn. Consumers are represented by a complete system of consumer demand equations. The model is used for a partial analysis of the welfare effects of an actual agricultural policy decision – the sale of large quantities of grains to the Soviet Union in the third quarter of 1972. The loss to consumers that is attributable to the increased grain exports did not reach its maximum until the second quarter of 1975. It is estimated that from 1973 to 1975 consumers suffered a reduction of meat consumption that they valued at $4.5 billion (U.S.). Furthermore, the effects of grain exports proved far larger than the losses due to the poor harvests of 1973 and 1974. Finally, attempts to shelter consumers from the effects of the increased corn exports, either by increased beef imports or increased grain price supports, would have had little success in compensating for the welfare loss actually suffered. Ce papier fail ?analvse de la réponse des secleurs de ?économie quant au bétail et à la volatile aux Flats-Unis, leur reponse à la politique gouvernementale et à?aulres coups exterieurs. En particulier, ce papier se concentre sur la mésure des changements au bien-étre des consommateurs. Un modèle économélrique qui est explicite représente ?approvisionnement du boeuf brouiè, du boeuf non-broutè, du pore el de la volatile. Lcar;action réciproque entre le marché de bélail et ie marché de grains est monlré par un modèle economelrique de ?offre et de la demande pour mats. Un système des équations représente la demande des consommateurs. On utilise le modèle pour ohtenir une analyse parlielle des effeis en ce qui concerne le bien-étre des consommateurs par suite ?une décision faite ?une politique agricole – celle de la vente de grandes quantités de grains à?Union soviétique au troisième quartier de ?année 1972. Laperte aux consommateurs qui est imputable aux exportations augmentées de grain n'apas alteinl son maximum jusqu'au deuxième quartier de 1975. On a eslimé que de 1973 à 1975 les consommateurs ont essuyé une réduction de la consommation de viande qu'ils ont evaluée à$4.5 milliard (en dollars des Etats-Unis). En outre, les effeis des exponations de grain se sont révélés bien grands que les effets des moissons maigres de 1973 el 1974. Finalement, des efforts de protéger les consommateurs contre les effets des exportations augmentees de maìs, ou par des importations augmentees de boeufou par augmenter le soutien pour le prix du grain auraient eu peu de succès à remplacer les pertes en fait essuyées.