1,721,658 research outputs found
Vertical specialization and the border effect puzzle
Full text linkA large body of empirical research finds that a pair of regions within a country tends to trade 10 to 20 times as much as an otherwise identical pair of regions across countries. In the context of the standard trade models, the large “border effect” is problematic, because it is consistent only with high elasticities of substitution between goods and/or high unobserved national border barriers. The author proposes a resolution to this puzzle based on vertical specialization, which occurs when regions or countries specialize only in particular stages of a good’s production sequence. The author develops a Ricardian model of intra-national and international trade, and shows how endogenous vertical specialization magnifies the effects of border barriers such as tariffs. He calibrates the model to match relative wages, trade shares, and vertical specialization for the U.S. and Canada. The model implies a much smaller border barrier and border effect than previous estimates.Consumption (Economics) ; Trade
Can multi-stage production explain the home bias in trade?
Full text linkA large empirical literature finds that there is too little international trade, and too much intra-national trade to be rationalized by observed international trade costs such as tariffs and transport costs. The literature uses frameworks in which goods are assumed to be produced in just one stage. This paper investigates whether the multi-stage nature of production helps explain the home bias in trade. The author shows that multi-stage production magnifies the effects of trade costs. He then calibrates a multi-stage production model to the U.S. and Canada. He solves the model with measures of trade costs constructed from data on tariffs, transport costs, and wholesale distribution margins. The model can explain about 3/8 of the Canada border effect; this is three times more than what a calibrated one-stage model can explain. The model also explains a good deal of Canada’s vertical specialization trade. Finally, a reverse engineering exercise suggests that the unknown or unobserved component of trade costs is smaller than observed trade costs.Production (Economic theory) ; Trade
International trade: why we don’t have more of it
Full text linkGlobalization has led to an enormous increase in international trade. Over the past 40 years, world exports as a share of output have doubled to almost 25 percent of world output. However, despite this enormous increase, economic evidence suggests that significant barriers to international trade still exist. In “International Trade: Why We Don’t Have More of It,” Edith Ostapik and Kei-Mu Yi summarize the latest developments in the measurement of international trade barriers.International trade
FIGURES 13–16 in New Records of the Genus Jessopocoris Carvalho, 1981 (Hemiptera: Miridae: Bryocorinae), with Descriptions of Two New Species Found in China
No full textFIGURES 13–16. Male genitalia of Jessopocoris yunnananus sp. nov.: 13–15. Left paramere in different views; 16. AedeagusPublished as part of Mu, Yi-Ran & Liu, Guo-Qing, 2012, New Records of the Genus Jessopocoris Carvalho, 1981 (Hemiptera: Miridae: Bryocorinae), with Descriptions of Two New Species Found in China, pp. 47-54 in Zootaxa 3573 on page 53, DOI: 10.5281/zenodo.28301
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Analysis of indirect message injection for MAC generation using stream ciphers
No full textThis paper presents a model for generating a MAC tag with a stream cipher using the input message indirectly. Several recent proposals represent instances of this model with slightly different options. We investigate the security of this model for different options, and identify cases which permit forgery attacks. Based on this, we present a new forgery attack on version 1.4 of 128-EIA3. Design recommendations to enhance the security of proposals following this general model are given
Characterization of the mouse LCN2 receptors in macrophage
No full text摘要
LCN2為疏水性分子結合蛋白家族的其中一員，同時也是一種急性反應蛋白，可藉由受體媒介的胞吞作用進入細胞內部。目前已知有兩種LCN2的受體（receptor）存在於細胞膜，分別為24p3R及megalin。由本實驗室研究結果已知子宮內膜異位炎形成過程中，腹腔液中的LCN2會有明顯增加的趨勢。而施加LCN2抗體則可以使子宮內膜的異位組織縮小，顯示LCN2在生殖系統中具有重要的功能。根據LCN2運送鐵離子的特性，推測當子宮內膜異位炎的形成過程中，腹腔液中高濃度的LCN2可藉巨噬細胞膜上受體使細胞內部鐵離子的濃度產生變化，進一步誘導細胞分泌細胞激素以促進子宮內膜異位炎的生成。因此本研究希望了解LCN2是否藉由受體媒介的胞吞作用造成巨噬細胞鐵離子的濃度的變化。此外，藉由shRNA的實驗分析巨噬細胞上實際參與反應的受體。在研究中利用手術建立小鼠子宮內膜異位症狀的模式，了解LCN2、24p3R及megalin基因在子宮內膜異位發育時的變化，以便推測LCN2與子通內膜異位症形成的關係。綜合所得結果證實LCN2主要是藉由24p3R將鐵離子帶入巨噬細胞中，而這樣的機制也許與子宮內膜異位的形成有關。而另一受體，Megalin，似乎在巨噬細胞對於LCN2的胞吞作用中並無明顯的功能。Abstract
LCN2 belongs to the lipocalin family and performs as an acute phase protein. It can be internalized into the cells via receptor-mediated endocytosis and play a role as an iron transporter. To our knowledge, two LCN2 membrane receptors, 24p3R and megalin, may be in charge of the LCN2 response. According to our previous studies, the level of LCN2 was highly induced in uterus and peritoneal fluid during the development of endometriosis. The administration of LCN2 antibody would diminish the ectopic endometriosis formation. It indicates the significance of LCN2 in reproductive system. LCN2, as an iron-transporter，may activate the macrophage in peritoneal cavity and trigger the secretion of cytokines from macrophage during the endometriosis formation via iron-internalization by LCN2. Currently，we attempt to confirm whether the macrophage can internalize the iron via LCN2 receptor-mediated endocytosis. Furthermore, using shRNA analysis, we identified the real receptor of LCN2 endocytosis in macrophage. The results showed that the iron could be transported the iron into the cell via LCN2-initicated endocytosis, and suggesting the 24p3R is an essential mediator. After establishing a mouse endometriosis model, we examined the gene expressions of LCN2、24p3R and megalin in the possibilities of endometriosis development. The results demonstrated that LCN2 internalized into the macrophage via 24p3R and might be associated with the formation of endometriosis. Megalin seemed to do nothing with LCN2 in macrophage endocytosis and endometriosis formation
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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