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1.
Using the Brazilian census and administrative panel data, the present paper provides evidence that the spatial concentration of analytical skills generates positive wage externalities for all workers in the local labor market. We rely on shift‐share instrumental variables to overcome the endogeneity of skill concentrations. The observed externality is independent from the classical market size economies. The estimates are robust to geography, institutions and workers' sorting on unobservable abilities.  相似文献   
2.
This study introduces a new measure of urban centrality. The proposed urban centrality index (UCI) constitutes an extension to the spatial separation index. Urban structure should be more accurately analyzed when considering a centrality scale (varying from extreme monocentricity to extreme polycentricity) than when considering a binary variable (monocentric or polycentric). The proposed index controls for differences in size and shape of the geographic areas for which data are available, and can be calculated using different variables such as employment and population densities, or trip generation rates. The properties of the index are illustrated with simulated artificial data sets and are compared with other similar measures proposed in the existing literature. The index is then applied to the urban structure of four metropolitan areas: Pittsburgh and Los Angeles in the United States; São Paulo, Brazil; and Paris, France. The index is compared with other traditional spatial agglomeration measures, such as global and local Moran's I, and density gradient estimations. El presente estudio introduce una nueva medida de centralidad. El índice de centralidad urbana propuesto (UCI, por sus siglas en inglés) es una extensión al índice de separación espacial (spatial separation index)(Midelfart‐Knarvik et al. 2000). El análisis de la estructura urbana resulta más preciso al usar el índice cuando se toma en cuenta una escala de continua de centralidad (que puede variar de un monocentrismo extremo a un policentrismo extremo) que cuando se considera una variable binaria (monocéntrica o policéntrica). El índex propuesto controla las diferencias de tamaño y forma de las áreas geográficas de las que se tienen datos, y puede ser calculada utilizando diferentes variables, como empleo y densidad poblacional, o tasas de generación de viajes. Las propiedades del índice se ilustran con conjuntos de datos artificiales simulados, y se comparan con otras mediciones similares en la literatura ya existente. Posteriormente, el índice es aplicado a la estructura urbana de cuatro áreas metropolitanas: Pittsburgh y Los Ángeles, en EEUU; San Pablo, en Brasil; y París, Francia. Finalmente, se compara el índice con otras mediciones tradicionales de aglomeración espacial, como el índice de Moran local y global, y estimaciones de gradiente de densidad. 本文介绍了一种度量城市中心性的新方法,提出的城市中心性指数(UCI)是对空间分离指数的扩展。当涉及到中心性规模(从极单中心到极多中心),不仅仅是二元变量(单中心或多中心),城市结构则需更加精确的测度。本文构建的指数可以通过数据可获取的不同大小和形状的地理单元控制,并通过不同变量(如就业与人口密度或者旅次产生率)测算得到。该指数的属性可以通过人工数据集的模拟示例说明,或者通过对比已有文献对相似指数的阐述加以说明。然后,通过将该指数应用于全球四个大都市区(美国匹兹堡和洛杉矶、巴西圣保罗和法国巴黎)的城市结构中进行检验。最后,将该指数与其他测度传统空间集聚指数如全局和局部Moran指数及密度梯度估计进行对比.  相似文献   
3.
Study of the Iberian Copper Age has experienced a remarkable upheaval in the last two decades. The discovery in central and southwestern Iberia of a significant number of ditched enclosures, a site type almost unknown in this region until the mid 1990s, has opened up new lines of research. Particularly interesting is the existence of some exceptionally large sites. Largest of all is Valencina de la Concepción (Seville, Spain), covering an area of 450 ha and featuring several outstanding megalithic monuments, thousands of pits and material assemblages revealing middle and long distance contacts. In this paper we discuss the implications of the Valencina mega-site for the study of settlement variability, monumentality and population aggregation as key phenomena in the rise in social complexity in Copper Age Iberia.  相似文献   
4.
Written sources and iconographic evidence suggest that honey and beehive products, used in culinary, medicinal, and technological functions since pre-Neolithic times, were likely known and used in Phoenician and Punic Sardinia. The role of these resources is nonetheless poorly understood because no direct evidence survives on a macroscopic level. Significant advances in the knowledge about beeswax and beehive products processing in the past have been offered in recent decades by organic residue analyses (ORA), an approach that enables the characterisation of surviving chemical compounds or suites of compounds that provide information relating to human activity in the past. The relatively recalcitrant nature of lipid compounds comprising beeswax means that this commodity is among the products that can be unambiguously identified through ORA. Here we present and discuss the results of analyses undertaken on 368 pottery sherds from Phoenician and Punic Sardinia (eighth to third century BCE). These analyses offer direct evidence for the presence of beehive products on the island, suggesting the use of honey for culinary purposes in pots, and possibly connecting one specific vessel category with beeswax decanting during beekeeping and honey production processes. Our results also now clearly illustrate the widespread use of beehive products in pre-Roman Sardinia.  相似文献   
5.
O’Gorman, J.P., Salgado, L., Varela, J., & Parras, A., 2013. Elasmosaurs (Sauropterygia, Plesiosauria) from the La Colonia Formation (Campanian–Maastrichtian), Argentina. Alcheringa 37, 257–265. ISSN 0311-5518.

Elasmosaur postcranial remains from the La Colonia Formation (Campanian–Maastrichtian), Chubut Province, Patagonia, Argentina, are described. The new material has small dimensions and caudal vertebrae with parapophyses strongly projected laterally—characters shared with some Elasmosauridae indet. from the coeval Allen Formation, Río Negro Province, Argentina. These features reinforce the similarities between the plesiosaur faunas to the north and south of the Somún Curá Plateau. The small size of these elasmosaurs may be palaeoecologically related to the marginal marine depositional environment of the sedimentary host rocks.

José P. O’Gorman [joseogorman@fcnym.unlp.edu.ar], División Paleontología Vertebrados, Museo de La Plata, Universidad Nacional de La Plata, Paseo del Bosque s/n., B1900FWA, La Plata, Argentina and [CONICET (Consejo Nacional de Investigaciones Científicas y Técnicas)]; Leonardo Salgado [salgadoleito@yahoo.com.ar], Instituto de Investigación en Paleobiología y Geología, Universidad Nacional de Río Negro, Isidro Lobo y Belgrano, 8332 General Roca, Argentina and [CONICET]; Julio Varela [julioadrianvarela@hotmail.com], and Ana Parras [aparras@exactas.unlpam.edu.ar], INCITAP (CONICET-UNLPam), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de La Pampa, Uruguay 151, 6300 Santa Rosa, La Pampa, Argentina. Received 27.7.2012; revised 19.10.2012; accepted 27.10.2012.  相似文献   
6.
Over the last twenty‐five years an anti‐Keynesian orthodox approach has envisaged a prominent role for reductions in fiscal deficits in developing countries. Expansionary fiscal policies have been said to result in excessive expansion of aggregate demand leading to current account deficits and inflation, as well as displacing private investment, thereby inhibiting output stabilization and employment recovery. Moreover, chronic fiscal deficits are supposed to be associated with high and explosive debt/GDP ratios. The purpose of this article is to assess the theoretical adequacy of the orthodox approach in the context of developing countries. The author clarifies some common misunderstandings and finds that none of the conventional arguments against fiscal activism is wholly convincing. At the heart of the debate lies the question of assumptions, economic structure and causation mechanisms. The orthodox stories regarding the macroeconomic effects of fiscal policy very often do not go beyond the simple monetarist assumptions or seek to verify the implications against the existing experiences and empirical data from developing countries.  相似文献   
7.
In 1979, a group of activists belonging to the EPLF (the Eritrean People's Liberation Front) came across a materialistic interpretation of the national question, which was penned at the turn of the century by one Dov Ber Borochov (1881–1917), a Russian–Jewish intellectual who was a leading ideologue of Marxist Zionism. Among the fruits of this encounter was a book advocating the Eritrean people's right to self-determination. Owing to developments in the Soviet Union and Marxist circles in the 1920s, Borochov's works were all but ignored throughout the remainder of the century. How, then, did a Spanish translation of his treatise, Nationalismo y lucha de clases (known in English as The National Question and Class Struggle), find its way into the hands of Eritrean nationalists? Furthermore, against the backdrop of Moscow and Havana's open support for Ethiopia, what attracted these Eritreans to the thought of an obscure Marxist–Zionist intellectual?  相似文献   
8.

In this paper, we explore the heuristic potential of a set of ideas about the structural and functional complexity of systems, proposed in the 1990s by theoretical biologist Daniel McShea. In particular, we focus on the structural aspects of the complexity exhibited by social systems organized into low- and intermediate-level functional units (i.e., groups and teams). To address this subject, we describe a methodology suited for measuring the complexity in the organization of work in such systems, which is primarily based on hierarchical task analysis. With this methodology, we approach a concrete case study: the construction of megalithic monuments in late prehistoric Iberia (ca. 3800–1800 BC). On the basis of the analysis of the three best documented, most structurally, and functionally complex monuments built within each of the three periods under study (Late Neolithic, Copper Age, and Early Bronze Age), we found that there was a trend towards less complexity in work organization related to monument building from the Late Neolithic to the Early Bronze Age. We discuss the importance of these results in light of the existing models of social complexity in European Later Prehistory, concluding that a more balanced view of social processes would be obtained if we look at complexity as a property of every different social system integrated into the whole society, and not as an exclusive property of the latter.

  相似文献   
9.
This article looks at the negotiations leading up to the Persian Tobacco Régie of 1890 as well as a previous failed Tobacco Régie in 1886. There exist only a few allusions to these two phases of the tobacco concession in the existing literature. Due to the newly uncovered diaries of the main commercial intermediary in these negotiations, the present article will be able to retrace, with precision, the events leading up to this economic concession of historical significance.  相似文献   
10.
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