不同种类的石油磺酸盐产品的原油沥青质分散性能评价

通过原油沥青分散性试验，考查了不同种类的石油磺酸盐对原油沥青质的分散性能，以便寻求一种评价驱油用表面活性剂应用性能的简便方法。试验结果表明，作为对现有标准评价方法的补充，该试验方法具有简单、实用、数据对比性强等特点，对于石油磺酸盐产品常规性能的例行检验尤为适用。与此同时，三种不同类型的石油磺酸盐产品对原油沥青质分散性的数据对比表明，具有长链稠环或短侧链多环芳烃结构的石油碘化产品，对于地层残余油沥青质的分散性较好，比普通的石油磺酸盐更适宜作为开采地下残余原油的实用型驱油用表面活性剂而使用。     

一种实用决策方法的研究：费用——有效性分析

一、费用──有效性分析的基本原理费用──有效性分析是企业决策中常用的一种定量方法,它主要是通过对实现目标的各种被选方案费用及其有效性进行定量分析和预算,并结合定性因素的考虑,作出适当的决定。它与通常的经济分析（如量本利分析）不同之处在于它要设法制订出一些定量的标准,以便能够同时来测定决策问题中的各种定性与定量因素。这种方法可以分析各种有广泛变化的物理和操作特性的决策问题,可以“权衡这样一些抉择方案,这些方案不可能用边际分析的方法,或不便于用折算为美元或其它种计量单位的方法来确定其中的最优方案”,…     

静、动力分析中的一种初始地应力场平衡方法

初始地应力场的平衡对于正确分析模拟具有围压依赖性和接触的问题尤其重要,准确模拟初始应力场是后续岩土工程动力响应分析正确与否的关键。为了实现岩土工程分析中初始竖向位移为零,且初始应力场不影响后续动力分析结果,基于ABAQUS软件,提出一种静、动力分析问题中的初始地应力场平衡方法。首先将人工边界考虑为固定边界,施加重力场,并求出边界节点上的反力;其次,将节点上的反力施加在黏弹性人工边界模型场地中,进行初始应力场平衡;最后,进行动力分析,并用理论解来验证计算结果。结果表明:固定边界情况下初始地应力平衡效果好,但不适用于动力分析;黏弹性边界情况下,初始地应力较大,并会影响动力分析结果;将固定边界情况下的边界节点反力施加在黏弹性边界模型上,既能够实现初始应力场较好地平衡,又不会影响动力分析结果。因此,提出的静、动力问题分析的初始应力场平衡方法合理并且有效,可为后续的岩土工程动力响应分析提供参考。     

Matching method to paradigm in strategy research: limitations of cross‐sectional analysis and some methodological alternatives

A central focus of empirical research in strategic management has been to understand the relationships associated with the structure–strategy–performance paradigm. To examine these relationships, investigators have relied extensively on cross‐sectional methods that embody the implicit assumption that model parameters are stable across firms and over time. Yet, many of the theoretical constructs used in strategic management have clear firm‐ and time‐specific components. Hence, it might be expected that the parameters of the relationships investigated empirically will vary across firms and over time. Whereas recent research has raised concerns about the use of cross‐sectional analysis when parameters vary over time, little attention has been given to the issue of parameter variability across firms. Given the focus of strategy researchers on firm‐level effects and the predominant reliance on cross‐sectional analysis, accounting for across‐firm variability is a significant methodological issue. Failure to account for such variability can lead to biased parameter estimates and incorrect inferences. This paper argues for the adoption of alternative methods that can overcome the limitations of a cross‐sectional analysis and it offers guidance on how researchers can proceed to use these alternative methods to explicitly incorporate or test for variation in model parameters across firms or over time. Copyright © 1999 John Wiley & Sons, Ltd.     

A quantitative analysis of trade policy responses to higher world agricultural commodity prices

The worldwide spike in prices of agricultural commodities in 2007–2008 elevated food security and social stability issues to the forefront, especially in many food-deficit countries. In order to mitigate the global food commodity price pressure on domestic markets, several major exporting and importing countries, mostly developing economies, adopted trade policy changes such as export bans (or raising export restrictions) or reducing import tariffs during the same period. This paper estimates the potential impacts of these policies on the world prices and trade of major agricultural commodities using a set of multi-country, multi-commodity, and partial-equilibrium models. Our findings suggest that over all, the trade policy responses in various countries increased the prices of all agricultural commodities, although the impact on the total net trade varies by commodity. The simulation results show that the overall impact of trade policy distortions on the world rice price is most significant at 24%, followed by wheat (14%) and barley (9%). In general, the poorer food-deficit countries/regions, which have limited power to manipulate their trade policies, experienced higher price increases compared to those major trading countries that adopted policy interventions. Also, the developing countries that are net importers which did not implement trade policy interventions experienced significant welfare losses resulting from interventions implemented by other major trading countries.     

Measurement and characterisation of the Digital Divide of Spanish regions at enterprise level. A comparative analysis with the European context

Until now, a reduced number of research is observed on the adoption and use of ICTs in enterprises and on the digital divide (DD) between them at regional scale in Europe. What is meant by DD are the differences in the levels of digital development of the enterprises; being the digital development the degree of adoption and use of ICTs and e-commerce by the firms. The aim of this piece of work is to characterise and measure the DD in the Spanish regions and those in the countries of the European Union based on the data of their enterprises with more than 10 employees which have used ICTs. The methodology is developed in the following stages: 1) Construction of a synthetic index of digital development (Enterprise Digital Development Index –EDDI-) for countries in the EU and Spanish regions. The production of this index is carried out based on the factors obtained with the factor analysis (FA) with the aim of identifying the key variables which define the different EDDI components. These variables come from the “Community survey on ICT usage and e-commerce in enterprises” of Eurostat. 2) Classification of Spanish regions into the groups of European countries with a similar level of EDDI components based on the discriminant analysis. Those groups are previously obtained by using cluster analysis. And 3) Comparative analysis of the DD between the Spanish regions and those in countries of the EU based on EDDI components and the identified groups. The study provides a synthetic index (EDDI) at European scale comprising 3 dimensions which permits obtaining: i) a ranking from more to less digital development of countries and regions permitting the measurement of the DD among them is established; and ii) a typology of European countries and Spanish regions is defined according to the 3 dimensions of EDDI. The main results of this piece of work show that the Spanish regions at enterprise level: i) are in a medium or higher level of digital development than their European counterparts, presenting, furthermore, a lower DD between them in relation to what happens in European countries; ii) stand out for having a higher digital inclusion than European countries in the ICTs related to infrastructures of internet access and for the interaction with the public authorities; and iii) have a digital development deficit in the integration of ICTs for e-commerce.     

The influence of digital divide frames on legislative passage and partisan sponsorship: A content analysis of digital equity legislation in the U.S. from 1990 to 2020

Government funding is essential for digital equity. Scholarship on policies to improve internet access often examines the funding mechanisms behind subsidies, or the quality and reach of services provided. However, a better understanding of the issues and constituencies to receive government support to date may help digital equity activists more strategically lobby for new digital divide policies in the future. To do this, we take a macro-level approach to Van Dijk's resources and appropriation theory and examine how the framing of all digital divide–related U.S. Congressional legislation introduced between 1990 and 2020 may be associated with a bill's passage or the political party of its sponsor. Content analysis revealed that bills highlighting privacy literacy programs, educational outcomes, and corporate transparency were more likely to be passed into legislation. Bills sponsored by Republicans were 422% more likely of being passed into legislation. Certain frames were also associated with partisan sponsorship: Republican-sponsored bills were more often framed around deregulation, privacy programs, corporate transparency, and rural access, whereas Democrat-sponsored bills were more often framed around digital skills such as digital literacy and educational outcomes. Findings serve as a historical record of digital equity priorities in the U.S. and highlight possible strategies for future policy design.