Equation of Motion Governing the Dynamics of Vertically Collapsing Buildings

The present paper aims at contributing to a discussion, opened by several authors, on the proper equation of motion that governs the vertical collapse of buildings. The most striking and tragic example is that of the World Trade Center Twin Towers, in New York City, about 10 years ago. This is a very complex problem and, besides dynamics, the analysis involves several areas of knowledge in mechanics, such as structural engineering, materials sciences, and thermodynamics, among others. Therefore, the goal of this work is far from claiming to deal with the problem in its completeness, leaving aside discussions about the modeling of the resistive load to collapse, for example. However, the following analysis, restricted to the study of motion, shows that the problem in question holds great similarity to the classic falling-chain problem, very much addressed in a number of different versions as the pioneering one, by von Buquoy or the one by Cayley. Following previous works, a simple single-degree-of-freedom model was readdressed and conceptually discussed. The form of Lagrange's equation, which leads to a proper equation of motion for the collapsing building, is a general and extended dissipative form, which is proper for systems with mass varying explicitly with position. The additional dissipative generalized force term, which was present in the extended form of the Lagrange equation, was shown to be derivable from a Rayleigh-like energy function. DOI: 10.1061/(ASCE)EM.1943-7889.0000453. (C) 2012 American Society of Civil Engineers.

The changing politics of preference formation in international trade negotiations: the European Union in the Doha Round

This research seeks to provide an explanation for variations of “politics” of preference formation in international trade negotiations. Building on the ‘policy determines politics’ argument, I hypothesize the existence of a causal relationship between issue-characteristics and their variations with politics dynamics and their variations. More specifically, this study seeks to integrate into a single analytical framework two dimensions along which variations in the “politics of preference formation” can be organized: configurations of power relationships among the relevant actors in the structures within which they interact as well as the logic and the motivations of the actors involved in the policy making process. To do so, I first construct a four-cell typology of ‘politics of preference formation’ and, then, I proceed by specifying that the type of state-society configurations as well as the type of actors’ motivations in the “politics of preference formation” depend, respectively, on the degree to which a policy issue is perceived as politically salient and on the extent to which the distributional implications of such an issue can be calculated by the relevant stakeholders in the policy making process. The empirical yardstick against which the validity of the theoretical argument proposed is tested is drawn from evidence concerning the European Union’s negotiating strategy in four negotiating areas in the context of the so-called WTO’s Doha Development Round of multilateral trade negotiations: agriculture, competition, environment and technical assistance and capacity building.

Stochastic foundations of dynamic trade and labor market models

This dissertation consists of three self-contained papers that are related to two main topics. In particular, the first and third studies focus on labor market modeling, whereas the second essay presents a dynamic international trade setup.rnrnIn Chapter "Expenses on Labor Market Reforms during Transitional Dynamics", we investigate the arising costs of a potential labor market reform from a government point of view. To analyze various effects of unemployment benefits system changes, this chapter develops a dynamic model with heterogeneous employed and unemployed workers.rn rnIn Chapter "Endogenous Markup Distributions", we study how markup distributions adjust when a closed economy opens up. In order to perform this analysis, we first present a closed-economy general-equilibrium industry dynamics model, where firms enter and exit markets, and then extend our analysis to the open-economy case.rn rnIn Chapter "Unemployment in the OECD - Pure Chance or Institutions?", we examine effects of aggregate shocks on the distribution of the unemployment rates in OECD member countries.rn rnIn all three chapters we model systems that behave randomly and operate on stochastic processes. We therefore exploit stochastic calculus that establishes clear methodological links between the chapters.

Landscape mosaics maps as a basis for spatial assessment and negotiation of ecosystem services and their trade-offs at the meso-scale: Examples from Laos, Madagascar and China

Mapping ecosystem services (ES) and their trade-offs is a key requirement for informed decision making for land use planning and management of natural resources that aim to move towards increasing the sustainability of landscapes. The negotiations of the purposes of landscapes and the services they should provide are difficult as there is an increasing number of stakeholders active at different levels with a variety of interests present on one particular landscape.Traditionally, land cover data is at the basis for mapping and spatial monitoring of ecosystem services. In light of complex landscapes it is however questionable whether land cover per se and as a spatial base unit is suitable for monitoring and management at the meso-scale. Often the characteristics of a landscape are defined by prevalence, composition and specific spatial and temporal patterns of different land cover types. The spatial delineation of shifting cultivation agriculture represents a prominent example of a land use system with its different land use intensities that requires alternative methodologies that go beyond the common remote sensing approaches of pixel-based land cover analysis due to the spatial and temporal dynamics of rotating cultivated and fallow fields.Against this background we advocate that adopting a landscape perspective to spatial planning and decision making offers new space for negotiation and collaboration, taking into account the needs of local resource users, and of the global community. For this purpose we introduce landscape mosaicsdefined as new spatial unit describing generalized land use types. Landscape mosaics have allowed us to chart different land use systems and land use intensities and permitted us to delineate changes in these land use systems based on changes of external claims on these landscapes. The underlying idea behindthe landscape mosaics is to use land cover data typically derived from remote sensing data and to analyse and classify spatial patterns of this land cover data using a moving window approach. We developed the landscape mosaics approach in tropical, forest dominated landscapesparticularly shifting cultivation areas and present examples ofour work from northern Laos, eastern Madagascarand Yunnan Province in China.

Ecosystem service trade-offs and stakeholder claims - a meso-scale study from a Madagascar biodiversity hotspot

The north-eastern escarpment of Madagascar has been labelled a global biodiversity hotspot due to its extremely high rates of endemic species which are heavily threatened by accelerated deforestation rates and landscape change. The traditional practice of shifting cultivation or "tavy" used by the majority of land users in this area to produce subsistence rice is commonly blamed for these threats. A wide range of stakeholders ranging from conservation to development agencies, and from the private to the public sector has therefore been involved in trying to find solutions to protect the remaining forest fragments and to increase agricultural production. Consequently, provisioning, regulating and socio-cultural services of this forest-mosaic landscape are fundamentally altered leading to trade-offs between them and consequently new winners and losers amongst the stakeholders at different scales. However, despite a growing amount of evidence from case studies analysing local changes, the regional dynamics of the landscape and their contribution to such trade-offs remain poorely understood. This study therefore aims at using generalised landscape units as a base for the assessment of multi-level stakeholder claims on ecosystem services to inform negotiation, planning and decision making at a meso-scale. The presented study applies a mixed-method approach combining remote sensing, GIS and socio-economic methods to reveal current landscape dynamics, their change over time and the corresponding ecosystem service trade-offs induced by diverse stakeholder claims on the regional level. In a first step a new regional land cover classification for three points in time (1995, 2005 and 2011) was conducted including agricultural classes characteristic for shifting cultivation systems. Secondly, a novel GIS approach, termed “landscape mosaics approach” originally developed to assess dynamics of shifting cultivation landscapes in Laos was applied. Through this approach generalised landscape mosaics were generated allowing for a better understanding of changes in land use intensities instead of land cover. As a next step we will try to use these landscape units as proxies to map provisioning and regulating ecosystem services throughout the region. Through the overlay with other regional background data such as accessibility and population density and information from a region-wide stakeholder analysis, multiscale trade-offs between different services will be highlighted. The trade-offs observed on the regional scale will then be validated through a socio-economic ground-truthing within selected sites at the local scale. We propose that such meso-scale knowledge is required by all stakeholders involved in decision making towards sustainable development of north-eastern Madagascar.

Unraveling the Conformational Determinants of Peptide Dendrimers Using Molecular Dynamics Simulations

Peptide dendrimers are synthetic tree-like molecules composed of amino acids. There are at least two kinds of preferential structural behaviors exhibited by these molecules, which acquire either compact or noncompact shapes. However, the key structural determinants of such behaviors remained, until now, unstudied. Herein, we conduct a comprehensive investigation of the structural determinants of peptide dendrimers by employing long molecular dynamics simulations to characterize an extended set of third generation dendrimers. Our results clearly show that a trade-off between electrostatic effects and hydrogen bond formation controls structure acquisition in these systems. Moreover, by selectively changing the dendrimers charge we are able to manipulate the exhibited compactness. In contrast, the length of branching residues does not seem to be a major structural determinant. Our results are in accordance with the most recent experimental evidence and shed some light on the key molecular level interactions controlling structure acquisition in these systems. Thus, the results presented constitute valuable insights that can contribute to the development of truly tailor-made dendritic systems.

Linking livelihood strategies with a regional level landscape mosaic to explore trade-offs between forest conservation and human wellbeing in a Madagascar biodiversity hotspot

The north-eastern escarpment of Madagascar contains the island’s last remaining large-scale humid forest massifs surrounded by diverse small-scale agricultural mosaics. There is high deforestation mainly caused by shifting cultivation practiced by local land users to produce upland rice for subsistence. Today, large protected areas restrict land users’ access to forests to collect wood and other forest products. Moreover, they are no more able to expand their cultivated land, which leads to shorter shifting cultivation cycles and decreasing plot sizes for irrigated rice and cash crop cultivation. Cash crop production of clove and vanilla is exposed to risks such as extreme inter-annual price fluctuations, pests and cyclones. In the absence of work opportunities, agricultural extension services and micro-finance schemes people are stuck in a poverty trap. New development strategies are needed to mitigate the trade-offs between forest conservation and human well-being. As landscape composition and livelihood strategies vary across the region, these strategies need to be spatially differentiated to avoid implementing generic solutions, which do not fit the local context. However, up to date, little is known about the spatial patterns of shifting cultivation and other land use systems at the regional level. This is mainly due to the high spatial and temporal dynamics inherent to shifting cultivation, which makes it difficult to monitor the dynamics of this land use system with remote sensing methods. Furthermore, knowledge about land users’ livelihood strategies and the risks and opportunities they face stems from very few local case studies. To overcome this challenge, firstly, we used remote sensing data and a landscape mosaic approach to delineate the main landscape types at the regional level. Secondly, we developed a land user typology based on socio-ecological data from household surveys in 45 villages spread throughout the region. Combining the land user typology with the landscape mosaic map allowed us to reveal spatial patterns of the interaction between landscapes and people and to better understand the trade-offs between forest conservation and local wellbeing. While shifting cultivation systems are being transformed into more intensive permanent agricultural systems in many countries around the globe, Madagascar seems to be an exception to this trend. Linking land cover information to human-environmental interactions over large areas is crucial to designing policies and to inform decision making for a more sustainable development of this resource-rich but poverty-prone context.

Ocean dynamics, not dust, have controlled equatorial Pacific productivity over the past 500,000 years

Biological productivity in the equatorial Pacific is relatively high compared with other low-latitude regimes, especially east of the dateline, where divergence driven by the trade winds brings nutrient rich waters of the Equatorial Undercurrent to the surface. The equatorial Pacific is one of the three principal high-nutrient low chlorophyll ocean regimes where biological utilization of nitrate and phosphate is limited, in part, by the availability of iron. Throughout most of the equatorial Pacific, upwelling of water from the Equatorial Undercurrent supplies far more dissolved iron than is delivered by dust, by as much as two orders of magnitude. Nevertheless, recent studies have inferred that the greater supply of dust during ice ages stimulated greater utilization of nutrients within the region of upwelling on the equator, thereby contributing to the sequestration of carbon in the ocean interior. Here we present proxy records for dust and for biological productivity over the past 500 ky at three sites spanning the breadth of the equatorial Pacific Ocean to test the dust fertilization hypothesis. Dust supply peaked under glacial conditions, consistent with previous studies, whereas proxies of export production exhibit maxima during ice age terminations. Temporal decoupling between dust supply and biological productivity indicates that other factors, likely involving ocean dynamics, played a greater role than dust in regulating equatorial Pacific productivity.

Skeletal trade-offs in coralline algae in response to ocean acidification

Ocean acidification is changing the marine environment, with potentially serious consequences for many organisms. Much of our understanding of ocean acidification effects comes from laboratory experiments, which demonstrate physiological responses over relatively short timescales. Observational studies and, more recently, experimental studies in natural systems suggest that ocean acidification will alter the structure of seaweed communities. Here, we provide a mechanistic understanding of altered competitive dynamics among a group of seaweeds, the crustose coralline algae (CCA). We compare CCA from historical experiments (1981-1997) with specimens from recent, identical experiments (2012) to describe morphological changes over this time period, which coincides with acidification of seawater in the Northeastern Pacific. Traditionally thick species decreased in thickness by a factor of 2.0-2.3, but did not experience a change in internal skeletal metrics. In contrast, traditionally thin species remained approximately the same thickness but reduced their total carbonate tissue by making thinner inter-filament cell walls. These changes represent alternative mechanisms for the reduction of calcium carbonate production in CCA and suggest energetic trade-offs related to the cost of building and maintaining a calcium carbonate skeleton as pH declines. Our classification of stress response by morphological type may be generalizable to CCA at other sites, as well as to other calcifying organisms with species-specific differences in morphological types.

Exploiting the Modularity of Value Chains: Inter-firm Dynamics of the Taiwanese Notebook PC Industry

This paper explores the inter-firm dynamics that govern the rise of capabilities of latecomer firms operating in global value chains. By extending and modifying the model proposed by Gereffi, Humphrey and Sturgeon [2005], I present a framework in which the rise of supplier capabilities is determined by interactions among the strategies of the firms. Based on a case study of the Taiwanese notebook PC industry, the paper will explore how the interactions among outsourcing strategies by lead firms from the developed countries, the learning strategies of Taiwanese suppliers, and the product strategy of powerful component vendors have driven the explosive growth of the industry after the 1990s. By so doing, the paper attempts to highlight the active roles firms play in determining the speed and direction of the rise in supplier capabilities.

The European Commission and International Trade Negotiations: A Principal-Agent Approach. IES WORKING PAPER 2/2011

Starting from the concept of delegation of power in external trade policy, this paper aims to investigate the dynamics surrounding the European Union’s position in international trade negotiations. The analysis centres on the role of the European Commission (the agent), which by means of Treaty-based delegation and as mandated by the Council (the principal) acts as the sole trade negotiator in the international sphere on behalf of the European Union (EU). The broader negotiating process is thus conceptualised as a threelevel game, where the Commission holds an intermediary position between the European and international levels and also interacts with the Member States in the Council. After an insight into the European decision-making process for external trade, the paper further analyses the Commission’s role during the multilateral trade negotiations of the Doha Development Round. By applying the principal-agent theory to international trade negotiations in general, and subsequently to the controversial agricultural negotiations, this paper seeks to investigate some of the potential sources of autonomy that the Commission can draw upon while upholding an EU position at the international level, in addition to the “hardball” job of balancing the interests of the Member States with those of World Trade Organisation (WTO) partners. Along these lines, the paper finally aims to contribute to the literature concerning agency autonomy in EU external trade relations but also to provide a better understanding of inter-institutional relations within the EU as they may unfold in practice.

Trade and geopolitics: should the EU engage with the Eurasian Economic Union? EPC Policy Brief, 2 April 2015

In an effort to find a solution to the deteriorating relationship between the EU and Russia, various commentators, policy-makers and experts have suggested that the EU should seriously consider engaging with the Eurasian Economic Union, as part of a new ‘grand bargain’ between Russia and the EU. If Ukraine will no longer be forced to choose between two integrating regimes, so the argument goes, Russian sensibilities can be pacified, which will in turn, hopefully, lead to peace in eastern Ukraine. However, according to Rilka Dragneva and Kataryna Wolczuk, these arguments are based on a number of problematic assumptions about integration dynamics in the eastern neighbourhood. In this Policy Brief, they recommend the EU better think twice before further engaging with the EEU.

Reflections on the Nature of Preferentialism in Services Trade

The Graduate Institute organized an academic workshop and roundtable on the occasion of EFTA's 50th Anniversary in Geneva under the chairmanship of H.E. Doris Leuthard, President of the Swiss Confederation. Pierre Sauve, Deputy Managing Director and Director of Studies, WTI and Co-leader, NCCR-Trade work programme on preferentialism and Anirudh Shingal, Senior Research Fellow, WTI and Co-leader, NCCR-Trade work programme on impact assessment of trade, co-authored a paper on the nature of preferentialism in services trade, which Anirudh presented at the workshop. The event was extremely well-attended by high profile dignitaries and academics including President Leuthard; Director General of the WTO, Pascal Lamy; trade ministers of Brazil and Finland; Jan Kubis, Executive Secretary of the UNECE and several current and former ambassadors. The academic workshop, moderated by Theresa Carpenter (Graduate Institute, Geneva), began in the morning with Prof. Victor Norman's (Norwegian School of Economics & Business Administration) presentation on the future of EFTA. Other presentations included those by Prof. Peter Egger (ETH Zurich) on the structural estimation of gravity models with market entry dynamics and by Prof. Richard Baldwin (Graduate Institute, Geneva) on 21st century regionalism. The high-profile Panel in the afternoon, moderated by Prof. Richard Baldwin, was led by President Leuthard who spoke on free trade agreements and the multilateral trading system in 2020. The keynote address at the Panel was delivered by Prof. Jagdish Bhagwati (Coulmbia University), who spoke on strengthening defences against protectionism and liberalizing trade.

Great Himalaya: Tourism and the dynamics of change in Nepal

Based on extensive field work and years of personal experience, the authors discuss the development of tourism in the Great Himalaya of Nepal from the early days of mountaineering to present-day trekking. Tourism and its potentials, drawbacks, and risks are illustrated with a focus on the Khumbu/Everest and Annapurna regions, the most popular mountain destinations in the country. The themes addressed include: growth and expansion of mountain tourism; employment and income generation; wealth, poverty, and livelihood as reflected in statistics and personal accounts by local people; the revival of trade with Tibet; tourism and the role of women; the crucial role played by institutions, policies and political stability; and environmental issues such as forest degradation, garbage management, and trail damage. With its numerous illustrations, text boxes and quotes, the book is intended for a broad readership of policy- and decision-makers in tourism and development, scholars, and tourists and mountaineers who take an interest in mountain development in the Great Himalaya and elsewhere.

Measuring globalisation: An evolutionary economic approach to tracking the evolution of international trade

Operationalising and measuring the concept of globalisation is important, as the extent to which the international economy is integrated has a direct impact on industrial dynamics, national trade policies and firm strategies. Using complex systems network analysis with longitudinal trade data from 1938 to 2003, this paper presents a new way to measure globalisation. It demonstrates that some important aspects of the international trade network have been remarkably stable over this period. However, several network measures have changed substantially over the same time frame. Taken together, these analyses provide a novel measure of globalisation.