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  • Public defence: 2018-12-20 10:00 De Geersalen, Geovetenskapens hus, Stockholm
    Malafry, Laurence
    Stockholm University, Faculty of Social Sciences, Department of Economics.
    Inequality and Macroeconomic Policy: Essays on Climate, Immigration and Fiscal Intervention2018Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This thesis consists of four self-contained essays in economics.

    Optimal Climate Policy with Household Wealth Inequality. Policy makers concerned with setting optimal carbon taxes to address climate change externalities often employ integrated assessment models (IAMs). While these models differ on their assumptions of climate damage impacts, discounting and technology, they conform on their assumption of complete markets and a representative household. In the face of global inequality and significant vulnerability of asset poor households, I relax the complete markets assumption and introduce a realistic degree of global household inequality. A simple experiment of introducing a range of global carbon taxes shows a household's position on the global wealth distribution predicts the identity of their most preferred carbon price.

    Immigration Shocks, Equilibrium Unemployment and Inequality. The purpose of this paper is to present a proof-of-concept model for assessing the impact of immigration shocks on a country's equilibrium unemployment, wages and inequality. The model implements labour market matching in the workhorse heterogeneous agent macro model with precautionary savings. In this setting, I perform several transition experiments exploring the channels and mechanisms through which a substantial immigration shock affects macroeconomic outcomes, including conditional welfare and economic integration. I find that the identity of the immigration cohort, as well as, features of the receiving economy matter for both the magnitude and direction of the response.

    Fiscal Multipliers in the 21st Century. Fiscal multipliers appear to vary greatly over time and space. Based on VARs for a large number of countries, we document a strong correlation between wealth inequality and the magnitude of fiscal multipliers. In an attempt to account for this finding, we develop a life-cycle, overlapping-generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of OECD economies, including the distribution of wages and wealth, social security, taxes, and government debt and study how a fiscal multiplier depends on various country characteristics. We find that the fiscal multiplier is highly sensitive to the fraction of the population who face binding credit constraints and also to the average wealth level in the economy. These findings together help us generate a cross-country pattern of multipliers that is quite similar to that in the data.

    Fiscal Consolidation Programs and Income Inequality. Following the Great Recession, many European countries implemented fiscal consolidation policies aimed at reducing government debt. Using three different empirical approaches, we document a strong positive relationship between higher income inequality and stronger recessive impacts of fiscal consolidation. To explain this finding, we develop a life-cycle, overlapping generations economy with uninsurable labor market risk. We calibrate our model to match key characteristics of a number of European economies, including the distribution of wages and wealth, and study the effects of fiscal consolidation programs. We find that higher income risk induces precautionary savings behavior, which decreases the proportion of credit-constrained agents in the economy. Our model produces a cross-country correlation between inequality and the fiscal consolidation multipliers in line with the data.

  • Public defence: 2019-01-08 13:00 sal FB42, AlbaNova universitetscentrum, Stockholm
    Rivero Losada, Illa
    Stockholm University, Faculty of Science, Department of Astronomy.
    Formation of solar bipolar regions: Magnetic flux concentrations from suction of the negative effective magnetic pressure instability2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Sunspots stand out on the visible solar surface. They appear as dark structures evolving and changing over time. They host energetic and violent events, like coronal mass ejections and flares, and concentrate strong magnetic fields. Hundreds of years of studies provide a record of sunspot cycles, as reported by the well-known butterfly diagram, as well as some of their general observational properties, such as size, maximum field strength, and lifetime. However, we lack a general theory that explains how the magnetic field cluster in the spots and how it evolves over time.

    This thesis studies the negative effective magnetic pressure instability (NEMPI) as a mechanism able to form such magnetic flux concentrations and thus magnetic spots. A weak magnetic field suppresses the turbulence locally and reduces the turbulent pressure. The resulting contraction concentrates the field further, which reduces the turbulent pressure even more, and so on. We study the conditions where NEMPI is excited, trying to reproduce some of the complexities of the solar environment. We focus on the effects of rotation, the change of stratification, and the influence of a simplified corona. We solve the magnetohydrodynamic equations using both direct numerical simulations and mean-field simulations of strongly stratified turbulence in a weak magnetic field.

    Even slow rotation with a Coriolis number of 0.01 can suppress the instability. Higher values of rotation lead to dynamo action, increasing the magnetic field in a new coupled dynamo-NEMPI system. In the solar case, the dependence of NEMPI on rotation constrains the depth where the instability can operate: since the Coriolis number is very small in the uppermost layers of the Sun, NEMPI can only be a shallow phenomenon. Changing the type of stratification from isothermal to polytropic pushes the instability further to the upper parts of the computational domain. Unlike the isothermal case, in the polytropic cases the density scale height is no longer constant, but the stratification decreases deeper down, making it increasingly difficult for NEMPI to operate.

    A corona changes dramatically the semblance of flux concentrations. A bipolar region is formed, instead of a single spot. It develops at the interface between the turbulent and the non-turbulent layers, forming a loop-like structure in the coronal layer. The bipoles move apart and finally decay and disappear. We study the structure in a wide range of parameters and test the physical conditions of its appearance. Higher stratification and imposed field strength intensify the magnetic structures, which reach even equipartition values, until a plateau and subsequent decrease occur. The increase of the domain size strengthens the maximum magnetic field and gives more coherence to the spots, keeping their sizes. We measure a strong large-scale downward and converging flows associated with the concentration of flux. Finally, we also include rotation in the two-layer model, confirming the previous results: slow rotation suppresses the formation of bipolar regions. A stronger imposed magnetic field alleviates the suppression somewhat and strengthens the structures.

    These studies demonstrate the viability of NEMPI to form magnetic flux concentrations in both monopolar and bipolar structures. We find that NEMPI can only develop in the uppermost layers, where the local Coriolis number is small and the stratification strong.

  • Public defence: 2019-01-10 10:00 Nordenskiöldsalen, Geovetenskapens hus, Stockholm
    Iqbal (وحید اقبال ), Waheed
    Stockholm University, Faculty of Science, Department of Meteorology .
    On atmospheric low frequency variability, teleconnections and link to jet variability2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The atmosphere is a complex system with an infinite number of independent variables. The best approximations of the atmosphere are made using numerical models. The use of such models provides an invaluable tool for studying the atmospheric system. In the atmosphere, narrow bands of strong winds at upper levels, called jet streams, impact the underlying large-scale weather conditions. In this Ph.D. thesis, I have studied jet stream variability from reanalyses and climate models. The regional climate model RCA4 simulations over South Asia reveal a good agreement between model results and reanalysis for jet stream representation. Lateral boundary data sources are believed to contribute to discrepancies over the mountainous regions.

    Currently, the weather forecasts have an upper limit of around 10 days. The atmospheric variability between 10 to 40 days is known as low frequency variability (LFV). This Ph.D. thesis also examined the LFV from a non-linear perspective, which indicated the existence of multiple recurring atmospheric conditions. The North Atlantic eddy-driven jet, which explains a major part of the winter variability over the North Atlantic region, has three preferred latitudinal positions situated south, closest to, and north of its climatological mean position. These positions represent, respectively, Greenland blocking, a low-pressure system over the North Atlantic, and a high-pressure system over the North Atlantic. An improved representation of this jet is reported from CMIP5 GCMs. However, the existence of three preferred latitudinal positions remains a challenge for these models.

    The statistical properties of recurring atmospheric conditions can potentially enhance current weather and climate predictions. Techniques from dynamical system theory, like unstable periodic orbits, can be employed to reconstruct such statistical properties. This has been demonstrated, for the first time, in a three-level baroclinic model, of intermediate complexity, for the Northern Hemisphere winter.

    In the Northern Hemisphere winter, there are times when the stratosphere gets warmer due to upward propagation of heat fluxes from the troposphere. This type of situation triggers a major sudden stratospheric warming, resulting in the equatorward shift of the jet streams and yielding much colder than usual surface conditions over the extratropics. I have studied thirty such events from the Japanese reanalysis data in relation to the three preferred latitudinal positions of the North Atlantic eddy-driven jet. The probability of strong upward propagation from the troposphere is significantly higher for the central position of the North Atlantic eddy-driven jet. These findings can potentially improve the troposphere-stratosphere predictions.

  • Public defence: 2019-01-10 13:00 Högbomsalen, Geovetenskapens hus, Stockholm
    Pas Schrijver, Annemiek
    Stockholm University, Faculty of Social Sciences, Department of Human Geography.
    Pastoralists, Mobility and Conservation: Shifting rules of access and control of grazing resources in Kenya's northern drylands2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Pastoral mobility is seen as the most effective strategy to make use of constantly shifting resources. In northern Kenya, mobile pastoralism as a highly-valued strategy to manage grazing areas and exploit resource variability is becoming more complex. Policy and project implementation has historically been driven by the imperative to secure land tenure and improve pasture in bounded areas through State-led settlement schemes. Relatively recently, increased (inter)national interests in nature and wildlife conservation on community land in the northern pastoralist regions see conservation and development as crucial and urgent requirements for stimulating economic growth and security. This study presents the case of Samburu pastoral mobility within the context of such shifting social and environmental circumstances. It focuses on changing rules of access and control of livestock resources. These transformations are analysed in the context of the large-scale establishment of community conservancies and what role these conservancies play in the actual use and transformation of space for pastoralists. Empirically, this thesis is based on a total of eighteen months fieldwork including semi-structured interviews and observations in Samburu, Isiolo and Laikipia. It demonstrates how the principal of reciprocal access to pasture between pastoralists is giving way to conditional access based on membership of more formal, territory-based institutions such as community conservancies. It further shows how access to private land may be open for negotiation through the formation of grazing arrangements, which are also used to control pastoralists’ movements beyond enclosed land. In spite of a rhetoric acknowledging the multiple benefits of livestock mobility, current policy entails a continuation of past policy and project implementation where prescriptions still revolve around conservation enclosures and settlement politics. The thesis concludes that such processes of territoriality are likely to produce unexpected and potentially disappointing outcomes, while struggle and conflict persist.

  • Public defence: 2019-01-11 10:00 Magnélisalen, Kemiska övningslaboratoriet, Stockholm
    Reitti, Marcus
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Diaryliodonium Salts: Synthesis, Applications and Computational Investigations2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Organic chemists have the ability to create complex organic molecules by connecting molecular building blocks in different ways. To name a few, these molecules are used as medicines, pesticides or in our household electronics, and are therefore crucial to life as we know it. While many excellent methods for the connection of these fragments are known, serious issues regarding efficiency and sustainability remain. Our research concerns the use of diaryliodonium salts as a way of improving on these issues. Diaryliodonium salts are hypervalent iodine reagents used to transfer aryl groups to suitable nucleophiles. This thesis concerns the synthesis of these reagents and their use in the formation of carbon-nitrogen and carbon-oxygen bonds.

    The first project investigates the possibility to synthesize unsymmetrical diaryliodonium salts starting from elemental iodine and arenes, as such a method could be more cost efficient and sustainable compared to existing methods starting from iodoarenes. It was found that highly sterically congested diaryliodonium salts could be synthesized in high yields.

    Next, we applied diaryliodonium salts in the arylation of nitrite to form aromatic nitro compounds. The methodology offered a broad scope with good to excellent yields. Furthermore, we presented the in situ functionalization of diaryliodonium salts that had been formed from iodoarenes and arenes. This conceptually novel approach could be a step towards a catalytic reaction using diaryliodonium salts.

    In the third project we investigated the mechanisms of O-arylations with diaryliodonium salts to provide a deeper understanding of the reaction pathways involved in product and byproduct formation. Reactions between electron-rich diaryliodonium salts, hydroxides or secondary alcohols were studied.  When using hydroxide as the nucleophile, the side products could be suppressed by the addition of aryne traps, suggesting such an intermediate in the reaction. A novel mechanism for the formation of the aryne was proposed based on DFT calculations.  When alcohols were used we detected the oxidation of the alcohol rather than aryne products. The oxidized product was shown to not originate from arynes or a radical process but was formed via an intramolecular deprotonation from a 4-coordinated intermediate as suggested by DFT-calculations and experiments.

    In the final project we developed two complementary methods for the synthesis of phenols using hydroxide surrogates as nucleophiles. These compounds have previously been difficult to make using diaryliodonium salts due to aryne formation or overarylation to form diaryl ethers. The first method used hydrogen peroxide as the surrogate and allowed formation of electron-deficient and moderately electron-rich phenols. The synthesis of ortho-alkyl substituted phenols could be accomplished by using silanols as the surrogate. This allowed us to synthesize several highly congested phenols in good yields. Highly electron-rich diaryliodonium salts were, however, not compatible with either of the two methods.

  • Public defence: 2019-01-11 13:00 JMK-salen, Garnisonen, Stockholm
    Faggella, Chiara
    Stockholm University, Faculty of Humanities, Department of Media Studies.
    "Not So Simple": Reassessing 1951, G.B. Giorgini and the launch of Italian fashion2019Doctoral thesis, monograph (Other academic)
    Abstract [en]

    This dissertation aims to shed light on the circumstances that allowed Italy to become a reputable country of origin in the international fashion market. In particular, my contribution to the historiography of Italian fashion is a reassessment of the role played by Giovanni Battista Giorgini, whose involvement with the fashion and handicraft industries has not been fully investigated by scholars so far. Drawing upon Marc Bloch’s paradigm against the “fetish of the single cause”, I argue that the historiography of Italian fashion is not so simple and linear as it has been presented so far. Instead, the appearance of Giorgini’s Italian High Fashion Shows from 1951 needs to be contextualized with other historical facts. By outlining a populous scenario of different actors and concurring events, this dissertation breaks away from the simplistic notion of Italian fashion being born overnight in 1951.

    Chapter one discusses the ways in which the idea of an Italian look emerged in the US press already before the end of World War II, and identifies the linguistic and visual features that characterized these earliest reports. Chapter two discusses the contributions to the promotion of Italian fashion merchandise in the United States by Max Ascoli, an antifascist Italian émigré who moved to New York in the late 1930s. His philanthropic involvement with the Italian handicraft industry is discussed in order to understand how the US market's faith in Italian goods had to be restored in relation to the perceived quality of exported goods. Chapter three focuses on Giovanni Battista Giorgini, presents a critical overview of his biography and identifies his earliest attempts at promoting Italian products to US and Canadian markets. Particular emphasis is given to Giorgini's role as an employee of the Allied Forces during the Allied occupation of Florence, and to the overlapping vicissitudes of his work with an American touring exhibition, Italy at Work, initiated by Ascoli. Chapter four discusses the activities of Giorgini’s competitors in Italy, that is agencies, associations and individuals that were operating in postwar times to export Italian fashion in the United States. Chapter five finally discusses the organization of Giorgini’s Italian High Fashion Shows in Florence between 1951 and 1953, the organization of his business venture and the ways in which the Shows solidified earlier representations of Italian fashion in the US press, becoming a benchmark for years to come.

    This study concludes that the historicisation of Giorgini, and his contribution to the promotion of Italy as an independent, non-derivative fashion market for export, was made possible thanks to a larger network of transatlantic actors that, immediately after World War II, strove for the same business goals. Eventually, this dissertation provides a historical perspective that defies the simplistic categorization of the past in straight compartments, in this case blurring the margins between Fascist and liberated, democratic Italy.

    The full text will be freely available from 2020-01-11 09:00