Does Industrialization Affect Segregation? Evidence from Nineteenth-Century Cairo

We investigate the impact of state industrialization on residential segregation between Muslims and non-Muslims in nineteenth-century Cairo using individual-level census samples from 1848 and1868. We measure local segregation by a simple inter-group isolation index, where Muslims' (non-Muslims') isolation is measured by the share of Muslim (non-Muslim) households in the local environment of each location. We find that relative to locations that did not witness changes in industrialization, the opening of Cairo railway station in 1856 differentially increased Muslims' isolation from non-Muslims (conversely, decreased non-Muslims' isolation) in its proximity and that the closures of textiles firms in 1848-1868 differentially decreased it. The results are arguably driven by a labor market mechanism, whereby state rms crowded in unskilled jobs that attracted greater net inows of rural immigrants and unskilled workers who were predominantly Muslims

The impact of competition on expert's information disclosure: the case of real estate brokers

Competition can theoretically counter or reinforce tendency of experts to pass biased information to customers. Using data from an online company connecting real estate brokers with clients who want to sell their properties, we show that more competition or lower opportunity to collude induce brokers to raise their initial price estimation by more than 3%. This is observed upstream, when experts appraise the property for sale. Competition partially prevents brokers from biaising downward evaluations, and is benecial to the client since it translates into a positive eect on listing and sale prices with no signicant eect on the time to sale

An objective rationale for the choice of regularisation parameter with application to global multiple-frequency S-wave tomography

International audienceIn a linear ill-posed inverse problem, the regularisation parameter (damping) controls the balance between minimising both the residual data misfit and the model norm. Poor knowledge of data uncertainties often makes the selection of damping rather arbitrary. To go beyond that subjectivity, an objective rationale for the choice of damping is presented, which is based on the coherency of delay-time estimates in different frequency bands. Our method is tailored to the problem of global multiple-frequency tomography (MFT), using a data set of 287 078 S-wave delay times measured in five frequency bands (10, 15, 22, 34, and 51 s central periods). Whereas for each ray path the delay-time estimates should vary coherently from one period to the other, the noise most likely is not coherent. Thus, the lack of coherency of the information in different frequency bands is exploited, using an analogy with the cross-validation method, to identify models dominated by noise. In addition, a sharp change of behaviour of the model ℓ∞-norm, as the damping becomes lower than a threshold value, is interpreted as the signature of data noise starting to significantly pollute at least one model component. Models with damping larger than this threshold are diagnosed as being constructed with poor data exploitation. Finally, a preferred model is selected from the remaining range of permitted model solutions. This choice is quasi-objective in terms of model interpretation, as the selected model shows a high degree of similarity with almost all other permitted models (correlation superior to 98% up to spherical harmonic degree 80). The obtained tomographic model is displayed in the mid lower-mantle (660-1910 km depth), and is shown to be compatible with three other recent global shear-velocity models. A wider application of the presented rationale should permit us to converge towards more objective seismic imaging of Earth's mantle

Effets d'une alcalose induite sur les paramètres métaboliques et sanguins lors d'un test: Cyclisme et Course à pied chez des triathlètes entraînés

International audienc

Iron(II) catalyzed reductive radical cyclization reactions of bromoacetals in the presence of NaBH4: optimization studies and mechanistic insights

Abstract 5-Exo-trig radical reductive cyclization reactions of bromoacetals are catalyzed by iron in the presence of the reducing agent NaBH4. Both iron(II) and iron(III) were found to effectively mediate these reactions. As shown by cyclic voltammetry, iron(III) can be reduced to an iron(II) precatalyst before passing through an identical reaction mechanism in which monoelectronic activation of the substrate would occur by an anionic hydridoiron(I) complex. Further studies have established that both the substrate (iodo- vs bromo-derivative) and the precatalytic mixture are decisive in determining the reaction outcome

Polarization state of the optical near-field

The polarization state of the optical electromagnetic field lying several nanometers above complex dielectric structures reveals the intricate light-matter interaction that occurs in this near-field zone. This information can only be extracted from an analysis of the polarization state of the detected light in the near-field. These polarization states can be calculated by different numerical methods well-suited to near--field optics. In this paper, we apply two different techniques (Localized Green Function Method and Differential Theory of Gratings) to separate each polarisation component associated with both electric and magnetic optical near-fields produced by nanometer sized objects. The analysis is carried out in two stages: in the first stage, we use a simple dipolar model to achieve insight into the physical origin of the near-field polarization state. In the second stage, we calculate accurate numerical field maps, simulating experimental near-field light detection, to supplement the data produced by analytical models. We conclude this study by demonstrating the role played by the near-field polarization in the formation of the local density of states.Comment: 9 pages, 11 figures, accepted for publication in Phys. Rev.

Cryptococcal Neuroradiological Lesions Correlate with Severity during Cryptococcal Meningoencephalitis in HIV-Positive Patients in the HAART Era

Cryptococcal meningoencephalitis has an overall global mortality rate of 20% in AIDS patients despite antifungals. There is a need for additional means of precise assessment of disease severity. We thus studied the radiological brain images available from 62 HIV-positive patients with cryptococcocal meningoencephalitis to analyse the brain lesions associated with cryptococcosis in relationship with disease severity, and the respective diagnostic contribution of magnetic resonance (MR) versus computed tomography (CT)

Four essays in urban economics and political economy

Cette thèse contribue à l’étude des interactions entre individus au sein des villes. Plus concrètement, mes recherches se concentrent sur trois thèmes principaux – (1) la ségrégation résidentielle, (2) la politique locale, (3) et le comportement des agents immobiliers – qui sont étudiés au travers de quatre études empiriques. La littérature sur la ségrégation résidentielle analyse dans quelle mesure plusieurs groupes de population sont capables d’interagir au sein d’un espace. Malgré les nombreuses études sur ce sujet, les conséquences de l’industrialisation sur la diversité ou l’isolation intergroupes (religieux ou ethniques), restent peu connus. Le premier chapitre de cette thèse est co-écrit avec le professeur Saleh. Nous documentons les conséquences de deux vagues d’industrialisation sur la ségrégation résidentielle entre Musulmans et non-Musulmans dans la ville du Caire au XIXème siècle. L’ouverture et la fermeture de grandes manufactures d’Etat nous permet d’observer l'évolution de l’isolation intergroupe dans les quartiers les plus impactés par ces vagues d’industrialisation. Nous mettons ainsi en parallèle l’arrivée de travailleurs non-qualifiés (majoritairement Musulmans) dans ces quartiers avec l’évolution de l’isolation intergroupe mesurée au niveau local. Dans ce premier projet, nous montrons que des politiques instaurées au niveau des villes impactent la capacité qu’ont les individus d’interagir. A l’inverse, les relations entre individus peuvent impacter la politique et les prises de décisions au niveau local. Dans le second chapitre de cette thèse, je montre que les réseaux familiaux jouent également un rôle important dans ces élections dans les villes de plus de 3500 habitants. Plus de 40% des listes lors des élections municipales comptent plusieurs individus de la même famille. Par ailleurs, les électeurs semblent réagir à ces “réseaux familiaux”. En effet, les listes composées de plusieurs individus de la même famille obtiennent moins de voix que les listes dont aucun individu ne semble concourir avec un autre membre de sa famille. Je discute ensuite quelques mécanismes qui pourraient expliquer ce résultat et je montre qu’il ne se réduit pas au fait que seules les têtes de listes inefficaces utilisent leurs réseaux familiaux. Il est possible que les électeurs sanctionnent le risque de népotisme. Dans un autre chapitre (chapitre 3), j’étudie les émissions de permis de construire au sein des villes et montre que les individus qui ont soutenus la majorité municipale durant les élections de 2008 obtiennent plus de permis de construire pour de nouveaux logements que ceux ayant soutenus d’autres listes. Je discute des mécanismes pouvant générer ce résultat. Les incitations des politiciens locaux semblent cruciales, notamment celles liées à la compétition politique. La différence d’obtention de permis de construire est par exemple plus importante dans les villes avec une faible compétition politique. Le dernier chapitre de cette thèse étudie le comportement des agents immobiliers. Des études précédentes (Levitt et Syverson (2008) notamment), illustrent le problème d’agence entre agents immobiliers et vendeurs. Les premiers souhaitent vendre plus rapidement (et donc peut-être moins cher) que les derniers. En conséquent, les agents pourraient souhaiter biaiser leurs estimations de la valeur des biens afin de convaincre les vendeurs de diminuer leurs prix. Dans un travail mené conjointement avec le professeur Cherbonnier, nous montrons qu’une augmentation de la concurrence peut partiellement résoudre ce problème. Les agents estiment les biens immobiliers à des valeurs supérieurs lorsqu’ils sont en concurrence, ce qui se traduit par des prix de mises en vente et des prix de vente plus élevés. A l’inverse, plus de coordination entre agents immobiliers impacte négativement les prix.The aim of this thesis is to contribute to the study of interactions among individuals within cities. It contains four empirical case studies which reflect a focus on three main themes. Namely, (1) residential segregation, (2) local politics and (3) the behavior of real estate agents. The literature on residential segregation investigates the extent to which different population groups living in the same area are able to interact with each other. Within this branch of studies, the impact of industrialization and labor market shocks on the diversity of neighborhoods and inter-group segregation remains an open question. It is the key question of the first chapter of this thesis, which is co-authored with professor Saleh. We document the consequences of two early industrialization waves on the residential segregation between Muslims and non-Muslims in nineteenth century Cairo. These early industrialization waves led to the opening and closure of large state firms. We relate changes in inter-group isolation to the massive arrival of unskilled workers who were predominantly Muslims in the proximity of these state firms. Through this first project, we show that policies enacted within cities affect the ability of individuals to interact. Conversely, relationships among individuals have an impact on local politics. For instance, Vignon (2014) recalls that in small villages, rivalries between persons and families play an important role during French municipal elections. In the second chapter, I show that family networks play an important role during these elections, even in large cities. It appears that more than 40% of lists competing during municipal elections in cities with more than 3,500 inhabitants are composed by several individuals from the same family. Moreover, voters seem to react when several members of the same family are registered on the same lists: these lists obtain fewer votes than lists which do not rely on family networks. I discuss several mechanisms which can explain this finding and I show that it does not reduce to a selection issue whereby only inefficient list leaders rely on family networks. On the contrary, it is possible that voters sanction risks of nepotism. In another chapter (chapter 3), I study whether the emission of building permits is biased in favor of individuals who supported the mayor during the municipal elections of 2008. I find that political supporters of municipal majorities (and their families) obtain more building permits than political supporters of other lists. I discuss whether this result is related to sorting of individuals among lists of candidates and how it is related to incentives of local politicians. I find that the difference in the obtaining of building permits is exacerbated in cities with a low level of political competition. Finally, the last chapter of this thesis focuses on the behavior of real estate agents. Previous investigations (such as, for instance, Levitt and Syverson, 2008) detect an agency problem between real-estate agents and sellers. The former group prefers to sell housings faster (and cheaper) than the latter one. As a consequence, agents might be tempted to minimize housing values when they give advices to sellers. In a joint work with professor Cherbonnier, we show that competition may partly solve this agency problem and that, on the contrary, ability to coordinate leads real-estate agents to minimize housing values, which translate into lower listing and selling prices

Four essays in urban economics and political economy

Cette thèse contribue à l’étude des interactions entre individus au sein des villes. Plus concrètement, mes recherches se concentrent sur trois thèmes principaux – (1) la ségrégation résidentielle, (2) la politique locale, (3) et le comportement des agents immobiliers – qui sont étudiés au travers de quatre études empiriques. La littérature sur la ségrégation résidentielle analyse dans quelle mesure plusieurs groupes de population sont capables d’interagir au sein d’un espace. Malgré les nombreuses études sur ce sujet, les conséquences de l’industrialisation sur la diversité ou l’isolation intergroupes (religieux ou ethniques), restent peu connus. Le premier chapitre de cette thèse est co-écrit avec le professeur Saleh. Nous documentons les conséquences de deux vagues d’industrialisation sur la ségrégation résidentielle entre Musulmans et non-Musulmans dans la ville du Caire au XIXème siècle. L’ouverture et la fermeture de grandes manufactures d’Etat nous permet d’observer l'évolution de l’isolation intergroupe dans les quartiers les plus impactés par ces vagues d’industrialisation. Nous mettons ainsi en parallèle l’arrivée de travailleurs non-qualifiés (majoritairement Musulmans) dans ces quartiers avec l’évolution de l’isolation intergroupe mesurée au niveau local. Dans ce premier projet, nous montrons que des politiques instaurées au niveau des villes impactent la capacité qu’ont les individus d’interagir. A l’inverse, les relations entre individus peuvent impacter la politique et les prises de décisions au niveau local. Dans le second chapitre de cette thèse, je montre que les réseaux familiaux jouent également un rôle important dans ces élections dans les villes de plus de 3500 habitants. Plus de 40% des listes lors des élections municipales comptent plusieurs individus de la même famille. Par ailleurs, les électeurs semblent réagir à ces “réseaux familiaux”. En effet, les listes composées de plusieurs individus de la même famille obtiennent moins de voix que les listes dont aucun individu ne semble concourir avec un autre membre de sa famille. Je discute ensuite quelques mécanismes qui pourraient expliquer ce résultat et je montre qu’il ne se réduit pas au fait que seules les têtes de listes inefficaces utilisent leurs réseaux familiaux. Il est possible que les électeurs sanctionnent le risque de népotisme. Dans un autre chapitre (chapitre 3), j’étudie les émissions de permis de construire au sein des villes et montre que les individus qui ont soutenus la majorité municipale durant les élections de 2008 obtiennent plus de permis de construire pour de nouveaux logements que ceux ayant soutenus d’autres listes. Je discute des mécanismes pouvant générer ce résultat. Les incitations des politiciens locaux semblent cruciales, notamment celles liées à la compétition politique. La différence d’obtention de permis de construire est par exemple plus importante dans les villes avec une faible compétition politique. Le dernier chapitre de cette thèse étudie le comportement des agents immobiliers. Des études précédentes (Levitt et Syverson (2008) notamment), illustrent le problème d’agence entre agents immobiliers et vendeurs. Les premiers souhaitent vendre plus rapidement (et donc peut-être moins cher) que les derniers. En conséquent, les agents pourraient souhaiter biaiser leurs estimations de la valeur des biens afin de convaincre les vendeurs de diminuer leurs prix. Dans un travail mené conjointement avec le professeur Cherbonnier, nous montrons qu’une augmentation de la concurrence peut partiellement résoudre ce problème. Les agents estiment les biens immobiliers à des valeurs supérieurs lorsqu’ils sont en concurrence, ce qui se traduit par des prix de mises en vente et des prix de vente plus élevés. A l’inverse, plus de coordination entre agents immobiliers impacte négativement les prix.The aim of this thesis is to contribute to the study of interactions among individuals within cities. It contains four empirical case studies which reflect a focus on three main themes. Namely, (1) residential segregation, (2) local politics and (3) the behavior of real estate agents. The literature on residential segregation investigates the extent to which different population groups living in the same area are able to interact with each other. Within this branch of studies, the impact of industrialization and labor market shocks on the diversity of neighborhoods and inter-group segregation remains an open question. It is the key question of the first chapter of this thesis, which is co-authored with professor Saleh. We document the consequences of two early industrialization waves on the residential segregation between Muslims and non-Muslims in nineteenth century Cairo. These early industrialization waves led to the opening and closure of large state firms. We relate changes in inter-group isolation to the massive arrival of unskilled workers who were predominantly Muslims in the proximity of these state firms. Through this first project, we show that policies enacted within cities affect the ability of individuals to interact. Conversely, relationships among individuals have an impact on local politics. For instance, Vignon (2014) recalls that in small villages, rivalries between persons and families play an important role during French municipal elections. In the second chapter, I show that family networks play an important role during these elections, even in large cities. It appears that more than 40% of lists competing during municipal elections in cities with more than 3,500 inhabitants are composed by several individuals from the same family. Moreover, voters seem to react when several members of the same family are registered on the same lists: these lists obtain fewer votes than lists which do not rely on family networks. I discuss several mechanisms which can explain this finding and I show that it does not reduce to a selection issue whereby only inefficient list leaders rely on family networks. On the contrary, it is possible that voters sanction risks of nepotism. In another chapter (chapter 3), I study whether the emission of building permits is biased in favor of individuals who supported the mayor during the municipal elections of 2008. I find that political supporters of municipal majorities (and their families) obtain more building permits than political supporters of other lists. I discuss whether this result is related to sorting of individuals among lists of candidates and how it is related to incentives of local politicians. I find that the difference in the obtaining of building permits is exacerbated in cities with a low level of political competition. Finally, the last chapter of this thesis focuses on the behavior of real estate agents. Previous investigations (such as, for instance, Levitt and Syverson, 2008) detect an agency problem between real-estate agents and sellers. The former group prefers to sell housings faster (and cheaper) than the latter one. As a consequence, agents might be tempted to minimize housing values when they give advices to sellers. In a joint work with professor Cherbonnier, we show that competition may partly solve this agency problem and that, on the contrary, ability to coordinate leads real-estate agents to minimize housing values, which translate into lower listing and selling prices