Browsing by Author "Lee, J"
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Item Open Access Analysis of Feature Intervisibility and Cumulative Visibility Using GIS, Bayesian and Spatial Statistics: A Study from the Mandara Mountains, Northern Cameroon(PLoS ONE, 2014-11-10) Wright, DK; MacEachern, S; Lee, JThe locations of diy-geδ-bay (DGB) sites in the Mandara Mountains, northern Cameroon are hypothesized to occur as a function of their ability to see and be seen from points on the surrounding landscape. A series of geostatistical, two-way and Bayesian logistic regression analyses were performed to test two hypotheses related to the intervisibility of the sites to one another and their visual prominence on the landscape. We determine that the intervisibility of the sites to one another is highly statistically significant when compared to 10 stratified-random permutations of DGB sites. Bayesian logistic regression additionally demonstrates that the visibility of the sites to points on the surrounding landscape is statistically significant. The location of sites appears to have also been selected on the basis of lower slope than random permutations of sites. Using statistical measures, many of which are not commonly employed in archaeological research, to evaluate aspects of visibility on the landscape, we conclude that the placement of DGB sites improved their conspicuousness for enhanced ritual, social cooperation and/or competition purposes.
Item Open Access Constructal design of gas-cooled electric power generators, self-pumping and atmospheric circulation(International Journal of Heat and Mass Transfer, 2015-08-24) Bejan, A; Lorente, S; Lee, J; Kim, Y© 2015 Elsevier Ltd. All rights reserved. Rotating electric machines generate heat volumetrically, and are cooled by forced convection aided by the self-pumping effect. In this paper we focus on the fundamental relationship between the internal flow architecture of the gas cooled winding and its thermal performance, which is represented by the nearly uniform distribution of peak temperature throughout the winding volume. We show that the cooling passages can be sized such that the volumetric cooling is most effective. From this finding follows the number of passages and their distribution through the heat generating volume. The principle is developed analytically, and it is then validated based on numerical simulations of the cooling architecture. The paper also reports the thermodynamics basis of the self-pumping effect, and its natural occurrence as free convection in general, which includes atmospheric circulation.Item Open Access Different stimuli, different spatial codes: a visual map and an auditory rate code for oculomotor space in the primate superior colliculus.(PLoS One, 2014) Groh, JM; Lee, JMaps are a mainstay of visual, somatosensory, and motor coding in many species. However, auditory maps of space have not been reported in the primate brain. Instead, recent studies have suggested that sound location may be encoded via broadly responsive neurons whose firing rates vary roughly proportionately with sound azimuth. Within frontal space, maps and such rate codes involve different response patterns at the level of individual neurons. Maps consist of neurons exhibiting circumscribed receptive fields, whereas rate codes involve open-ended response patterns that peak in the periphery. This coding format discrepancy therefore poses a potential problem for brain regions responsible for representing both visual and auditory information. Here, we investigated the coding of auditory space in the primate superior colliculus(SC), a structure known to contain visual and oculomotor maps for guiding saccades. We report that, for visual stimuli, neurons showed circumscribed receptive fields consistent with a map, but for auditory stimuli, they had open-ended response patterns consistent with a rate or level-of-activity code for location. The discrepant response patterns were not segregated into different neural populations but occurred in the same neurons. We show that a read-out algorithm in which the site and level of SC activity both contribute to the computation of stimulus location is successful at evaluating the discrepant visual and auditory codes, and can account for subtle but systematic differences in the accuracy of auditory compared to visual saccades. This suggests that a given population of neurons can use different codes to support appropriate multimodal behavior.Item Open Access Economic and Social Upgrading in Global Value Chains and Industrial Clusters: Why Governance Matters(Journal of Business Ethics, 2016-01-01) Gereffi, G; Lee, J© 2014, Springer Science+Business Media Dordrecht.The burgeoning literature on global value chains (GVCs) has recast our understanding of how industrial clusters are shaped by their ties to the international economy, but within this context, the role played by corporate social responsibility (CSR) continues to evolve. New research in the past decade allows us to better understand how CSR is linked to industrial clusters and GVCs. With geographic production and trade patterns in many industries becoming concentrated in the global South, lead firms in GVCs have been under growing pressure to link economic and social upgrading in more integrated forms of CSR. This is leading to a confluence of “private governance” (corporate codes of conduct and monitoring), “social governance” (civil society pressure on business from labor organizations and non-governmental organizations), and “public governance” (government policies to support gains by labor groups and environmental activists). This new form of “synergistic governance” is illustrated with evidence from recent studies of GVCs and industrial clusters, as well as advances in theorizing about new patterns of governance in GVCs and clusters.Item Open Access Global value Chains, rising power firms and economic and social upgrading(Critical Perspectives on International Business, 2015-01-01) Lee, J; Gereffi, G© Emerald Group Publishing Limited.Purpose – The purpose of this paper is to introduce the global value chain (GVC) approach to understand the relationship between multinational enterprises (MNEs) and the changing patterns of global trade, investment and production, and its impact on economic and social upgrading. It aims to illuminate how GVCs can advance our understanding about MNEs and rising power (RP) firms and their impact on economic and social upgrading in fragmented and dispersed global production systems. Design/methodology/approach – The paper reviews theGVCliterature focusing on two conceptual elements of the GVC approach, governance and upgrading, and highlights three key recent developments in GVCs: concentration, regionalization and synergistic governance. Findings – The paper underscores the complicated role of GVCs in shaping economic and social upgrading for emerging economies, RP firms and developing country firms in general. Rising geographic and organizational concentration in GVCs leads to the uneven distribution of upgrading opportunities in favor of RP firms, and yet economic upgrading may be elusive even for the most established suppliers because of power asymmetry with global buyers. Shifting end markets and the regionalization of value chains can benefit RP firms by presenting alternative markets for upgrading. Yet, without further upgrading, such benefits may be achieved at the expense of social downgrading. Finally, the ineffectiveness of private standards to achieve social upgrading has led to calls for synergistic governance through the cooperation of private, public and social actors, both global and local. Originality/value – The paper illuminates how the GVC approach and its key concepts can contribute to the critical international business and RP firms literature by examining the latest dynamics in GVCs and their impacts on economic and social development in developing countries.Item Open Access Globalization, Recession and the Internationalization of Industrial Districts: Experiences from the Italian Gold Jewellery Industry(European Planning Studies, 2014-01-01) De Marchi, V; Lee, J; Gereffi, GGlobalization and the recent recession crisis are significantly challenging Italian industrial districts (IDs), leading to deep transformations in their internationalization, innovation and organization strategies. With our empirical focus on a single industry (gold jewellery) and a specific country (Italy) and through the theoretical lenses of the global value chain (GVC) approach, the evidence in this article sheds light on the differences in how three IDs within Italy's gold jewellery sector (Valenza Po, Arezzo and Vicenza) compete in the global arena. Our comparative analysis reveals striking differences among these districts with regard to their upstream and downstream internationalization strategies in response to two industry shocks: increasing global competition in the early 2000s and the world economic recession of 2008-2009. Our explanation for the varied gold jewellery district responses to these two global crises involves both internal and external factors: (1) structural differences between the three IDs; (2) distinct business strategies; and (3) how these districts are linked to the gold jewellery GVC. © 2013 © 2013 Taylor & Francis.Item Open Access Globalization, Recession and the Internationalization of Industrial Districts: Experiences from the Italian Gold Jewellery Industry(European Planning Studies, 2013) De Marchi, Valentina; Gereffi, Gary; Lee, JItem Open Access Innovation, upgrading, and governance in cross-sectoral global value chains: The case of smartphones(Industrial and Corporate Change, 2021-02-01) Lee, J; Gereffi, GThe fourth industrial revolution challenges the existing understanding of innovation and upgrading in the global economy. It blurs traditional sectoral boundaries based on distinctive products and technologies and calls into question a traditional global value chain (GVC) perspective, which, similar to the sectoral systems of innovation approach, examines innovation and upgrading from a sector-based orientation. Building upon the recent reformulation and extension of GVC governance theory, this article proposes the notion of cross-sectoral GVC governance to capture the new stage of platform-based industrial development. It specifies the conceptual dimensions of cross-sectoral GVC governance in terms of the mode of governance (i.e., driving, linking, and normalizing), the overall GVC structure in terms of polarity, and firm strategies of managing GVCs. The proposed framework is illustrated using the case of smartphones as a platform product, focusing on four lead firms - Samsung, Apple, Huawei, and Google - to showcase divergent firm strategies for governing cross-sectoral linkages related to innovation and upgrading.Item Open Access Linking dynamical heterogeneity to static amorphous order(Journal of Statistical Mechanics: Theory and Experiment, 2016-07-01) Charbonneau, P; Dyer, E; Lee, J; Yaida, S© 2016 IOP Publishing Ltd and SISSA Medialab srl. Glass-forming liquids grow dramatically sluggish upon cooling. This slowdown has long been thought to be accompanied by a growing correlation length. Characteristic dynamical and static length scales, however, have been observed to grow at different rates, which perplexes the relationship between the two and with the slowdown. Here, we show the existence of a direct link between dynamical sluggishness and static point-to-set correlations, holding at the local level as we probe different environments within a liquid. This link, which is stronger and more general than that observed with locally preferred structures, suggests the existence of an intimate relationship between structure and dynamics in a broader range of glass-forming liquids than previously thought.Item Open Access Social Upgrading in Mobile Phone GVCs: Firm-level Comparisons of Working Conditions and Labor Rights(Labour in Global Value Chains in Asia, 2016-11-01) Lee, J; Gereffi, G; Lee, SHItem Open Access Targeting A20 decreases glioma stem cell survival and tumor growth.(PLoS Biol, 2010-02-23) Hjelmeland, AB; Wu, Q; Wickman, S; Eyler, C; Heddleston, J; Shi, Q; Lathia, JD; Macswords, J; Lee, J; McLendon, RE; Rich, JNGlioblastomas are deadly cancers that display a functional cellular hierarchy maintained by self-renewing glioblastoma stem cells (GSCs). GSCs are regulated by molecular pathways distinct from the bulk tumor that may be useful therapeutic targets. We determined that A20 (TNFAIP3), a regulator of cell survival and the NF-kappaB pathway, is overexpressed in GSCs relative to non-stem glioblastoma cells at both the mRNA and protein levels. To determine the functional significance of A20 in GSCs, we targeted A20 expression with lentiviral-mediated delivery of short hairpin RNA (shRNA). Inhibiting A20 expression decreased GSC growth and survival through mechanisms associated with decreased cell-cycle progression and decreased phosphorylation of p65/RelA. Elevated levels of A20 in GSCs contributed to apoptotic resistance: GSCs were less susceptible to TNFalpha-induced cell death than matched non-stem glioma cells, but A20 knockdown sensitized GSCs to TNFalpha-mediated apoptosis. The decreased survival of GSCs upon A20 knockdown contributed to the reduced ability of these cells to self-renew in primary and secondary neurosphere formation assays. The tumorigenic potential of GSCs was decreased with A20 targeting, resulting in increased survival of mice bearing human glioma xenografts. In silico analysis of a glioma patient genomic database indicates that A20 overexpression and amplification is inversely correlated with survival. Together these data indicate that A20 contributes to glioma maintenance through effects on the glioma stem cell subpopulation. Although inactivating mutations in A20 in lymphoma suggest A20 can act as a tumor suppressor, similar point mutations have not been identified through glioma genomic sequencing: in fact, our data suggest A20 may function as a tumor enhancer in glioma through promotion of GSC survival. A20 anticancer therapies should therefore be viewed with caution as effects will likely differ depending on the tumor type.Item Open Access The evolutionary design of condensers(Journal of Applied Physics, 2015-01-01) Bejan, A; Lee, J; Lorente, S; Kim, Y© 2015 AIP Publishing LLC. Condensers are flow architectures needed to provide high rates of condensation (or cooling) per unit volume, in enclosures with fixed volume. Their design has not changed from configurations consisting of the banks of horizontal tubes. In this paper, we outline a free path to evolving the design by exploring new features of flow configuration: flattened tubes, multiple tube sizes, arrays of flattened tubes, vertical tubes with turbulent film flow, forced convection condensation instead of gravity driven condensation, and the optimal length of a horizontal tube, i.e., the number of tubes in a column aligned with vapor cross flow. We show that the condensation density can be increased sizably by varying freely and without bias the morphology of the flow system: the shapes and arrangement of the cooled surfaces on which condensation occurs. The evolution of technology is described in terms of the special time direction of the useful (purposeful) changes in the configuration (shapes, arrangements) of surfaces on which flow/condensation occurs. This explains what "evolution" means. It is an important step for physics, not just technology.Item Open Access Trade policies, firm strategies, and adaptive reconfigurations of global value chains(Journal of International Business Policy, 2021-12-01) Gereffi, G; Lim, HC; Lee, JThe recent U.S.–China trade conflicts cast new light on the role of trade policies in global value chains (GVCs). Contrary to the expectation that trade restrictions lead to the shrinking or disruption of GVCs, our article posits that the unintended consequences of trade policies (both restrictions and trade agreements) are amplified by the prevalence and organizational complexity of GVCs. We anchor our argument in the historical evolution of three classic GVCs – apparel, automobiles, and electronics – from the 1970s to the present. Our framework highlights the dynamic interaction between GVC-oriented trade policies and firm strategies, which often has counterintuitive implications in terms of upgrading outcomes for the countries and companies involved in these GVCs. While trade policies often provide momentum for an adaptive reconfiguration of GVCs, firms’ strategic actions are crucial in modifying the geographic and organizational features of GVCs in ways that support their longevity. Firm strategies can mediate the effect of trade policies on GVC configurations in two ways: (1) firms can accommodate trade restrictions and trade agreements by altering supply and demand locations and by switching supply-chain partners; and (2) firms pursue diverse strategies to upgrade their value chain activities, leveraging the shifting geographies associated with new trade rules.Item Open Access Why the World Suddenly Cares About Global Supply Chains(Journal of Supply Chain Management, 2012-07-01) Gereffi, G; Lee, JThe global value chain (GVC) concept has gained popularity as a way to analyze the international expansion and geographical fragmentation of contemporary supply chains and value creation and capture therein. It has been used broadly in academic publications that examine a wide range of global industries, and by many of the international organizations concerned with economic development. This note highlights some of the main features of GVC analysis and discusses the relationship between the core concepts of governance and upgrading. The key dynamics of contemporary global supply chains and their implications for global production and trade are illustrated by: (1) the consolidation of global value chains and the new geography of value creation and capture, with an emphasis on China; (2) the key roles of global supermarkets and private standards in agri-food supply chains; and (3) how the recent economic crisis contributes to shifting end markets and the regionalization of value chains. It concludes with a discussion of the future direction of GVC analysis and a potential collaboration with supply chain researchers. © 2012 Institute for Supply Management, Inc.