A WARM EMBRACE OR THE COLD SHOULDER? WAGE AND EMPLOYMENT OUTCOMES IN ETHNIC ENCLAVES

This paper examines how immigrant enclaves influence labor market outcomes. We examine the effect of variation in ethnic concentration across counties and county subdivisions on both immigrant earnings and employment using the non‐public use, 1‐in‐6 sample of the 2000 U.S. Census. We find that there is heterogeneity in enclave impacts by ethnic group and skill composition of the enclave. While some groups tend to suffer from lower wages and employment propensities when residing in areas with larger ethnic concentrations, others have higher wages and improved employment opportunities in enclaves. (JEL J61, J15, R23)     

Review of Microstructural Evidence of Magmatic and Solid-State Flow

Evidence of magmatic flow includes: (a) parallel to sub-parallel alignment of elongate euhedral crystals (e.g., of feldspar or hornblende) that are not internally deformed, (b) imbrication (‘tiling’) of elongate euhedral crystals that are not internally deformed, (c) insufficient solid-state strain in regions between aligned or imbricated crystals to accommodate phenocryst rotation, (d) elongation of microgranitoid enclaves without plastic deformation of the minerals, (e) magmatic flow foliations and elongate microgranitoid enclaves deflected around xenoliths, and (f) schlieren layering (if due to flow sorting) in the absence of plastic deformation of the minerals involved. These features are consistent with rotation of crystals in a much weaker medium, namely a melt phase, at a stage when the magma has become viscous enough to preserve the alignment. Evidence of solid-state flow includes: (a) internal deformation and recrystallization of grains, (b) recrystallized “tails,” (c) elongation of recrystallized aggregates (e.g. of quartz and mica), (d) grainsize reduction, (e) fine-grained folia anastomosing around less deformed relics, (f) microcline twinning, (g) myrmekite, (h) flame perthite, (i) boudinage of strong minerals, typically with recrystallized aggregates of weaker minerals (e.g. quartz and mica) between the boudins, (j) foliation passing through, rather than around enclaves, and (k) heterogeneous strain with local mylonitic zones. Several criteria suggest “submagmatic flow,” including recrystallized feldspar, inferred transitions from magmatic imbrication to solid-state S/C arrangements, evidence of c-slip in quartz, and especially evidence of migration of residual melt into lower-pressure sites. Recent experimental studies indicate that a change from grain-supported flow to suspension flow typically occurs in deforming magmas at melt contents of between 20% to 40%, and that large amounts of strain may accumulate in magmas without being recorded by the final fabric. At lower melt percentages, perhaps as low as a few percent, depending on the minerals and their shapes, strain may be accommodated by: (a) melt-assisted grain-boundary sliding, (b) contact-melting assisted grain-boundary migration, (c) strain partitioning into melt-rich zones, (d) intracrystalline plastic deformation (c-slip in quartz indicating plastic deformation at temperatures near the granite solidus), and (f) transfer of melt to sites of low mean stress. The only indication of strain in the absence of crystal plasticity may be an alignment of crystals. Moreover, magmatic flow microstructures may be destroyed by fracturing, crystal plasticity and recrystallization before the magma reaches its solidus. Many rocks show evidence of solid-state flow superimposed on magmatic flow. Evidence of magmatic flow is commonly preserved in deformed felsic metamorphic rocks: for example the alignment of rectangular K-feldspar megacrysts and of microgranitoid enclaves. However, absence of alignment does not preclude a magmatic origin for K-feldspar megacrysts in felsic gneisses, as magmatic flow may cease before the magma becomes viscous enough to preserve an alignment.     

江西师范大学瑶湖校区环境景观规划设计方案研究

在充分理解现状与前期规划创意的基础上，通过强化环境空间的脉络结构、场所精神的提炼与情感文脉的注入，从而形成能够适应现代教育观念与未来发展的优美的大学校园环境。     

Foreign capital and technology transfer in a dynamic model

We consider a dynamic three-sector dual-economy model when the technology transfer takes place from the foreign enclave to the labor-intensive domestic enclave. The long-run equilibrium and the comparative steady-state effects are analyzed. It is shown that the policy of subsidization to the foreign enclave may satisfy the conflicting tasks of raising national income and lowering unemployment simulataneously in the long run. Subsidization to a domestic enclave does not satisfy both the objectives.     

ETHNIC ENCLAVES AND LABOR MARKETS: AN ANALYSIS OF IMMIGRANT OUTCOMES IN CALIFORNIA

The goal of this article is to examine how immigrant enclaves influence labor market outcomes. We examine the effect of ethnic concentrations on earnings in the state of California. Individual-level wage equations that control for several observable human capital and demographic characteristics are estimated. In addition, we introduce a measure that captures an ethnic group's proportion of the metropolitan area population. In general, we find that any potentially positive enclave effects are likely to be offset by negative labor market competition effects. In particular, most enclave effects become insignificant after controlling for metro area–specific effects . ( JEL J61, J31)     

嵌入性创新网络与科技型小微企业创新绩效:网络能力中介效应研究

科技型小微企业嵌入于创新网络中,通过自主性发挥网络构建与管理能力,进一步分享创新网络资源,提高创新实力。基于中国软件谷(南京)及相关创业孵化园246家软件企业问卷调查结果,运用SPSS、LISREL软件进行统计分析,实证研究网络能力对嵌入性创新网络与科技型小微企业创新绩效的中介效应。结果表明:(1)嵌入性创新网络稳定性有利于科技型小微企业创新绩效的提升;(2)嵌入性创新网络强度越大,科技型小微企业网络能力越强;(3)科技型小微企业网络能力越强,创新绩效提升越明显;(4)科技型小微企网络能力有助于促进嵌入性创新网络对创新绩效的提升作用。     

Competition and open source with perfect software compatibility

In this paper we study duopolistic competition between closed and open source software. Inspired by recent contributions on open source, we propose a two-stage game with perfect information and product differentiation, in which producers first set software quality and then determine prices (the price is zero for open source programs). We assume perfect software compatibility and model lock-in effects, a network externality component of software quality, and accumulation of experience in software use and implementation. In comparison to the monopolistic benchmark case, we argue that, in a duopoly created by the emergence of an open source program, the proprietary software producer will reduce its selling price if: (i) its network of users is larger than the open source network and its consumers are largely familiar with its program, (ii) it has a small network of unskilled consumers. On the other hand, the price of proprietary software will increase if its users form a large, but poorly-skilled network. Furthermore, we show that, in all of the above cases, the hedonic quality of proprietary software increases. Finally, by modeling experience accumulation processes through difference equations, we show that the ratio between the closed and open source programs’ opportunity costs for software learning and deployment plays a crucial role in shaping market outcomes. If open source software remains too complex and technical for unskilled or time-pressed users, a shared market solution, in which both programs are adopted, is likely to emerge. However, if opportunity costs in learning and understanding open source programs are particularly low, or at least equal to the opportunity costs of a closed-source program, then open source dominance emerges (i.e. markets tip to open source).     

Traceroute的网络拓扑发现及其效率优化措施

网络拓扑发现是网络工程的一个重要的研究子分支，是实现网络管理的基础性环节。同时，网络拓扑发现是对宏观网络进行科学布局的基础，也是进行网络建设、网络信息、网络协议设计与评价以及相关网络算法改进的重要依据。在介绍网络拓扑发现的概念的基础上，重点分析了基于Traceroute的网络拓扑发现原理，探讨了其发现效率优化措施。     

English Proficiency and Earnings of Foreign-Born Immigrants in the USA from 1980 to 2000: The Effect of Minority-Language Enclaves

This paper compares the importance of English proficiency (EP) on earnings among the foreign-born immigrants from 1980 to 2000 and shows its importance varied over time. The key issue examined is changes in the impact of being in a minority-language enclave and its interactions with the return to EP. Results show that the negative effects of enclaves were the greatest in 1990 and such effects were significantly stronger among those fluent English speakers. The relationship between EP and the enclave effects is explored, which confirms their strong interaction in 1990. However, the evidence of fluent speakers' large migrations from enclaves between 1990 and 2000 is not strong, as of the 24 foreign language groups, 13 showed decreases in fluency in enclaves relative to non-enclaves, while 11 showed increases in fluency in enclaves relative to non-enclaves. This may relate to non-wage benefits of living in enclaves, such as social benefits.     

Macroprudential consolidation policy in interbank networks

Can consolidation policy be made consistent with macro-prudential supervision? In this study, we seek to provide new insights on this key-question using a network approach. We study how the resilience of a banking network evolves as we shock an initially homogenous competitive market with a sequence of M&A activities that significantly alter the topology of the network. We study how different M&A treatments impact the structural vulnerabilities that can propagate through the system and we show that the severity of contagion and default dynamics depends on the chosen treatment. The desirability of alternative competitive settings (such as a hub-centered market or a more concentrated and yet symmetric market) are assessed against a homogenous benchmark case. We show that the choice depends crucially on the size of the interbank market and the level of bank capitalization. The existence of a large highly connected hub is beneficial in a capitalized network with a well-developed interbank market, but it can significantly weaken the system’s resilience in a poorly capitalized market. Antitrust and competition authorities should adopt a state-contingent approach to M&A activities according to the market conditions in which banks operate.     

Protectionism, Export Requirements, and Joint Ventures

Economic distortions often accompany the attempt by lower-income countries to develop. This paper examines the consequences of two such distortions: an export-share requirement whereby foreign capital producing in a local enclave is allowed to sell only a fraction of its output in the local protected market, and some local capital must be allowed into a joint venture in the enclave, even if it must be paid a higher return there than foreign capital earns in its country of origin. The welfare effect of such measures is investigated as well as the effect on local wages of measures that drive out some foreign investment. Such a loss of foreign capital may serve to raise the wage rate.     

A virtual voyage through 3D structures generated by chaotic mixing of magmas and numerical simulations: a new approach for understanding spatial and temporal complexity of magma dynamics

In this contribution, we present a virtual voyage through 3D structures generated by chaotic mixing of magmas and numerical simulations with the aim to highlight the power of 3D representations in the understanding of this geological phenomenon. In particular, samples of mixed juveniles from Salina island (Southern Italy) are reconstructed in 3D by serial lapping and digital montage and numerical simulations are performed by using a 3D chaotic dynamical system. Natural and simulated magma mixing structures are visualized by using several multimedia tools including animations and “virtual reality” models. It is shown that magma interaction processes can generate large spatial and temporal compositional heterogeneities in magmatic systems. The same topological structures are observed in both 3D reconstructed rock samples and chaotic numerical simulations, indicating that the mixing of magmas is governed by chaotic dynamics. The use of 3D multimedia models gives the opportunity to penetrate into magma mixing structures and to understand their significance in the context of magma dynamics. Such an approach is very powerful since multimedia tools can strongly capture the attention of the reader bringing him/her into an interactive and memorable geological experience.     

“资源-能力-关系”框架下网络能力与科技企业孵化器服务创新绩效研究

以资源基础理论、组织学习理论、组织间关系理论及网络能力理论为基础，构建“资源-能力-关系”框架下网络能力、知识积累、知识基与科技企业孵化器服务创新绩效概念框架并提出研究假设，通过大样本数据调查，运用SPSS、Amos软件对概念框架进行信效度检验和结构方程模型分析。结果显示，网络能力（网络资源拼凑能力、网络组织学习能力和网络关系交互能力）对知识积累具有显著正向影响；知识积累与科技企业孵化器服务创新绩效之间具有显著正相关关系，知识基对知识积累与科技企业孵化器服务创新绩效关系具有显著正向调节作用。     

Strategic network formation through peering and service agreements

We introduce a game theoretic model of network formation in an effort to understand the complex system of business relationships between various Internet entities (e.g., Autonomous Systems, enterprise networks, residential customers). In our model we are given a network topology of nodes and links where the nodes act as the players of the game, and links represent potential contracts. Nodes wish to satisfy their demands, which earn potential revenues, but may have to pay their neighbors for links incident to them. We incorporate some of the qualities of Internet business relationships, including customer–provider and peering contracts. We show that every Nash equilibrium can be represented by a circulation flow of utility with certain constraints. This allows us to prove bounds on the prices of anarchy and stability. We also focus on the quality of equilibria achievable through centralized incentives.     

Formation of Migrant Networks

In this paper, we provide the first direct evidence on the internal structure of the migrant social network. By using a purposely designed survey on Sri Lankan immigrants living in Milan, we show that the pattern of within‐group link formation is heterogeneous across immigrants, and differentiated according to the network function (i.e., accommodation, credit, job‐finding). We find that migrants tend to interact with co‐nationals who come from nearby localities at origin, while the time of arrival has a U‐shaped effect. Once the link is formed, material support is provided mainly to relatives, while early migrant fellows are helpful for job‐finding.     

旅游目的地网络营销系统与旅游产业发展耦合分析

为研究各省区市的旅游目的地网络营销系统与旅游产业发展水平的耦合关系,采用SPSS17.0统计软件,利用多指标综合评价的主成分分析法(PCA),对我国大陆31个省区市的旅游产业发展水平进行综合定量评价;然后,运用多层次分析法,结合问卷调查数据,对大陆各省区市旅游目的地网络营销系统进行定量评价,得出各省区市旅游目的地网络营销系统综合评价值;最后,对旅游目的地网络营销系统与旅游产业发展进行耦合分析,达到帮助旅游目的地制定正确的旅游网络营销及产业发展政策的目的。     

恶意软件隐私侵权问题研究

恶意软件是指在未明确提示用户或未经用户许可的情况下,在用户计算机或其他终端上安装运行,侵犯用户合法权益的软件。恶意软件侵犯网民关于网络生活不受非法侵入的隐私,剥夺网络用户对个人隐私的控制权,且侵权方式快捷,覆盖面极广,侵权后果严重。中国应通过单独立法、公益诉讼、行业自律等途径规范恶意软件的运行。     

Platform strategies: how the position in the network drives success

Scholars have focused on platform strategies for a long time, moving from a product perspective to an industry-wide one. In particular, the decision to open the platform to external complementors has been studied through the perspective of platform leadership. The digital age is now moving from a closed approach versus an open approach. Is being a platform leader still imperative or is participating in a network of existing platforms still a suitable strategy as well? What kind of collaborations within an ecosystem leads to better performances? Leveraging social network analysis is performed within the network formed by mobile apps in the Health and Fitness category; this research shows how the decision of being (or not) a platform provider has an impact on the performances, but the position within the network mediates this impact. Based on the results obtained, research and managerial implications can be established.     

REACTOR SAFETY AND RISK ISSUES

This paper surveys trends and conclusions in federally sponsored studies of nuclear reactor safety and their implications for nuclear regulation. The paper finds that recent studies do not rule out the possibility of light water reactor accidents equal to or even larger in size than the 1986 Chernobyl accident. The probability of such an event – involving both core melt and prompt containment failure – is quite small, but the Nuclear Regulatory Commission's (NRC's) estimated probability of core melt is significantly higher. The paper reviews the NRC's use of these findings through a probabilistic cost-benefit framework, and it concludes that a greater and focused NRC commitment to risk reduction is justified.     

Petrophysical characterization and natural fracturing in an olivine-dolerite aquifer

As part of a study investigating the naturally-occurring fractures in mafic rocks, two holes were drilled 450 m apart through the Palisades dolerite sill in New York. Well-2 is 229 m deep and Well-3 was drilled to 305 m, both penetrating through the sill and into the underlying Triassic sediments of the Newark Basin. Both holes were logged with downhole geophysical tools, including the BHTV, which acoustically images fractures intersecting the well. Understanding the fracture pattern, density, and porosity in the sill is essential for identifying possible zones of active fluid flow and high permeability. Using the BHTV logs, 96 and 203 fractures were digitally mapped within the sill in Well-2 and Well-3, respectively. Most fractures appear to dip steeply (76-78°). There is a shift in fracture orientation, however, and these fractures may or may not be continuous over the short lateral distance between Well-2 and Well-3. The lithology of the sill as identified by drill chips is nevertheless continuous between the holes. Both intersect a 7 m thick olivine-rich layer about 15 m above the bottom of the sill. Several fractures identified in Well-2 have large apparent aperture (>6cm) which correspond to high porosity zones (6-14%) observed in the logs. Resistivity logs were used to compute porosity using Archie's law and match well with the neutron porosity log in Well-2. We use the relationship between porosity and fracture aperture within the sill at Well-2 to infer the porosity in Well-3. High-porosity, large-aperture zones, including the target olivine layer, are identified in both holes. Changes in the temperature gradient log indicate active fluid flow in the sill, although flow appears to be most active in the sediments. Direct field measurements of bulk permeability, hydrologic modeling of fluid flow and calibration of fracture and log porosity will be undertaken in the future.