Computing congruences of modular forms and Galois representations modulo prime powers

This article starts a computational study of congruences of modular forms and modular Galoisrepresentations modulo prime powers. Algorithms are described that compute the maximum integermodulo which two monic coprime integral polynomials have a root in common in a sensethat is defined. These techniques are applied to the study of congruences of modular forms andmodular Galois representations modulo prime powers. Finally, some computational results withimplications on the (non-)liftability of modular forms modulo prime powers and possible generalisationsof level raising are presented.

Decentralization, happiness and the perception of institutions

This paper analyses whether the different powers and resources at the disposal of local and regional governments across Europe deliver greater satisfaction with political institutions and lead to greater personal happiness. The analysis uses microdata from the four available waves of the European social survey (2002, 2004, 2006 and 2008), including more than 160,000 observations of individuals living in 29 European countries. Our results reveal that political and fiscal decentralization have a positive and significant effect on individuals’ overall happiness. Fiscal decentralization also exerts a significant effect on the level of satisfaction with political and economic institutions and with the education and health systems, whereas the effect of political decentralization on these variables is more limited. The results show that citizens seem to be happier with the actual capacity of their local governments to deliver than with the general principle that they can have a say on their daily politics and policies. Keywords: Happiness, well-being, satisfaction, fiscal and political decentralization, Europe. JEL codes: H11, H77

Raman scattering and photoluminescence analysis of silicon on insulator structures obtained by single and multiple oxygen implants

An analysis of silicon on insulator structures obtained by single and multiple implants by means of Raman scattering and photoluminescence spectroscopy is reported. The Raman spectra obtained with different excitation powers and wavelengths indicate the presence of a tensile strain in the top silicon layer of the structures. The comparison between the spectra measured in both kinds of samples points out the existence in the multiple implant material of a lower strain for a penetration depth about 300 nm and a higher strain for higher penetration depths. These results have been correlated with transmission electron microscopy observations, which have allowed to associate the higher strain to the presence of SiO2 precipitates in the top silicon layer, close to the buried oxide. The found lower strain is in agreement with the better quality expected for this material, which is corroborated by the photoluminescence data.

A Fair and Secure Cluster Formation Process for Ad Hoc Networks

An efficient approach for organizing large ad hoc networks is to divide the nodesinto multiple clusters and designate, for each cluster, a clusterhead which is responsible forholding intercluster control information. The role of a clusterhead entails rights and duties.On the one hand, it has a dominant position in front of the others because it manages theconnectivity and has access to other node¿s sensitive information. But on the other hand, theclusterhead role also has some associated costs. Hence, in order to prevent malicious nodesfrom taking control of the group in a fraudulent way and avoid selfish attacks from suitablenodes, the clusterhead needs to be elected in a secure way. In this paper we present a novelsolution that guarantees the clusterhead is elected in a cheat-proof manner.

Protectionist but globalised? Latin American custom duties and trade during the pre-1914 belle époque

While it is true that Latin American republics had no rival on maximising revenues from custom collection during the belle époque, this paper shows that Latin American countries were also generous importers, only behind the larger commercial countries of Western Europe in terms of imports per capita. Latin American citizens were much more linked to international trade than citizens of most regions of the world. Their relation to the world economy was tighter both via their imports and their exports relative to their population and income levels. This paper comes to show that there is no contradiction between the high custom collection by the Latin American republics and their high level of interaction with the global economy in the pre-1914 belle époque, although large country differences can be observed when descending from the regional to the national level.

Development and Democratization

Current studies, mainly focused on the postwar period, are split on the impact of development on democracy. Examining panel data that runs from early nineteenth century (a time where hardly any democracy was in place) to the end of the twentieth century, I show income matters positively for democratization – both after controlling for country and time effects and instrumenting for income. Since the effect of time partly varies over time, with some historical periods that are more favorable to democracy than others, I investigate the domestic variables (a decreasing marginal effect of growth in already developed economies) and international factors (the strategies of great powers toward small countries) generating that result. I finally probe the underlying processes through which income shapes political institutions, showing that development produces key changes in the distribution and nature of wealth that, in turn, make democracy a stable political outcome.

Mixed Blessing? EP Oversight of the ESDP and the Constitutional Treaty

As commonly held, the European Security and Defence Policy (ESDP) suffers from a “double democratic deficit”: the EP has a marginal role in the ESDP-making process and the national parliaments remain unable to account for their own government. Therefore pressure coming from these two institutions had been exercised during the Convention on the Future of Europe to improve the democratic oversight on this rapidly evolving policy. This paper investigates the innovations included in the Constitutional Treaty, focusing specifically on the new role granted to the EP. It shows that even though this text does not substantially modify the inter-institutional balance of powers in the ESDP area, the EP may take advantage of some of its articles to become an actor in the ESDP-control process in the ‘living constitution.

Bit loading for MIMO with statistical channel information at the transmitter and ZF receivers

For single-user MIMO communication with uncoded and coded QAM signals, we propose bit and power loading schemes that rely only on channel distribution information at the transmitter. To that end, we develop the relationship between the average bit error probability at the output of a ZF linear receiver and the bit rates and powers allocated at the transmitter. This relationship, and the fact that a ZF receiver decouples the MIMO parallel channels, allow leveraging bit loading algorithms already existing in the literature. We solve dual bit rate maximization and power minimization problems and present performance resultsthat illustrate the gains of the proposed scheme with respect toa non-optimized transmission.

On a series of Goldbach and Euler

Theorem 1 of Euler s paper of 1737 'Variae Observationes Circa Series Infinitas', states the astonishing result that the series of all unit fractions whose denominators are perfect powers of integers minus unity has sum one. Euler attributes the Theorem to Goldbach. The proof is one of those examples of misuse of divergent series to obtain correct results so frequent during the seventeenth and eighteenth centuries. We examine this proof closelyand, with the help of some insight provided by a modern (and completely dierent) proof of the Goldbach-Euler Theorem, we present a rational reconstruction in terms which could be considered rigorous by modern Weierstrassian standards. At the same time, with a few ideas borrowed from nonstandard analysis we see how the same reconstruction can be also be considered rigorous by modern Robinsonian standards. This last approach, though, is completely in tune with Goldbach and Euler s proof. We hope to convince the reader then how, a few simple ideas from nonstandard analysis, vindicate Euler's work.

State capacity and military conflict

In 1500, Europe was composed of hundreds of statelets and principalities, with weak central authority,no monopoly over the legitimate use of violence, and overlapping jurisdictions. By 1800, only ahandful of powerful, centralized nation states remained. We build a model that explains both the emergenceof capable states and growing divergence between European powers. We argue that the impactof war was crucial for state building, and depended on: i) the financial cost of war, and ii) a country sinitial level of domestic political fragmentation. We emphasize the role of the "Military Revolution",which raised the cost of war. Initially, this caused more cohesive states to invest in state capacity, whilemore divided states rationally dropped out of the competition, causing divergence between Europeanstates. As the cost of war escalated further, all states engaged in a "race to the top" towards greater statebuilding.

Contractual allocation of decision rights and incentives: The case of automobile distribution

We analyze empirically the allocation of rights and monetary incentives in automobile franchise contracts. These contracts substantially restrict the decision rights of dealers and grant manufacturers extensive contractual completion and enforcement powers, converting the manufacturers, de facto, in a sort of quasi-judiciary instance. Variation in the allocation of decision rights andincentive intensity is explained by the incidence of moral hazard in the relation. In particular, when the cost of dealer moral hazard is higher and the risk of manufactureropportunism is lower, manufacturers enjoy more discretion in determining the performance required from their dealers and in using mechanisms such as monitoring, termination and monetary incentives to ensure such performance is provided. We also explore the existence of interdependencies between the different elements of the system. and find some complementarities between completion and termination rights, and between monitoring rights and the intensity of incentives.

Electrical and optical properties of Zn-In-Sn-O transparent conducting thin films

Indium tin oxide (ITO) is one of the widely used transparent conductive oxides (TCO) for application as transparent electrode in thin film silicon solar cells or thin film transistors owing to its low resistivity and high transparency. Nevertheless, indium is a scarce and expensive element and ITO films require high deposition temperature to achieve good electrical and optical properties. On the other hand, although not competing as ITO, doped Zinc Oxide (ZnO) is a promising and cheaper alternative. Therefore, our strategy has been to deposit ITO and ZnO multicomponent thin films at room temperature by radiofrequency (RF) magnetron co-sputtering in order to achieve TCOs with reduced indium content. Thin films of the quaternary system Zn-In-Sn-O (ZITO) with improved electrical and optical properties have been achieved. The samples were deposited by applying different RF powers to ZnO target while keeping a constant RF power to ITO target. This led to ZITO films with zinc content ratio varying between 0 and 67%. The optical, electrical and morphological properties have been thoroughly studied. The film composition was analysed by X-ray Photoelectron Spectroscopy. The films with 17% zinc content ratio showed the lowest resistivity (6.6 × 10 - 4 Ω cm) and the highest transmittance (above 80% in the visible range). Though X-ray Diffraction studies showed amorphous nature for the films, using High Resolution Transmission Electron Microscopy we found that the microstructure of the films consisted of nanometric crystals embedded in a compact amorphous matrix. The effect of post deposition annealing on the films in both reducing and oxidizing atmospheres were studied. The changes were found to strongly depend on the zinc content ratio in the films.

Personality traits and psychopathology predict burnout symptoms after two years in a sample of Catalan police officers

The operational aspects of psychological assessment are well documented (e.g. Murphy and Davidshofer, 1994). Essentially, the process involves the administration of one or more valid psychological tests in order to assess a person’s suitability to a task or situation. The resulting data and report are then used by police psychologists to assist in determining the suitability of the applicant for police duties. In Catalunya, this task is carried out during basic training for police career agent in the evaluation of psychological conditions for the use of the weapon. Police work can be one of the most stressful jobs, and it frequently leads to the development of burnout syndrome. In their day-to-day tasks, police officers are constantly subjected to various stressors (de la Fuente, Aguayo, Vargas and Cañadas, 2013). The most widely accepted definition of the burnout syndrome is one that describes it as a response to chronic work stress made up of three components: emotional exhaustion, depersonalisation and low personal accomplishment (Maslach & Jackson, 1981). Some studies showed that personality characteristics, and positive and negative affectivity explained significant variance in each of the burnout dimensions (Alarcon, Eschleman and Bowling, 2009).

Nutritional and feeding ecology in the Cory"s shearwater (Calonectris diomedea).

In birds, parents adjust their feeding behaviour according to breeding duties, which ultimately may lead to seasonal adjustments in nutritional physiology and hematology over the breeding season. Although avian physiology has been widely investigated in captivity, few studies have integrated individual changes in feeding and physiological ecology throughout the breeding season in wild birds. To study relationships between feeding ecology and nutritional ecophysiology in Cory"s shearwater Calonectris diomedea, we weighed and took blood samples from 28 males and 19 females during the pre-laying, egg-laying, incubation, hatching and chick-rearing periods of the breeding season. In addition, we fitted 6 birds with geolocators to track their foraging movements throughout the reproductive period. Thus, we examined individual changes in (1) nutritional condition (biochemistry metabolites); (2) oxygen carrying capacity (hematology); and (3) feeding areas and foraging effort (stable isotopes and foraging movements). Geolocators revealed a latitudinal shift in main feeding areas towards more southern and more neritic waters throughout the breeding season, which is consistent with the steady increase in δ13C signatures in the blood. Geolocators also showed a decrease in foraging effort from egg-laying to hatching, reflecting the activity decrease associated with incubation duties. Plasma metabolites, body mass and oxygen carrying capacity were associated with temporal changes in nutritional state and foraging effort in relation to recovery after migration, egg formation, fasting shifts during incubation and chick provisioning. This study shows that combining physiological and ecological approaches can help us understand the influence of breeding duties on feeding ecology and nutritional physiology in wild birds.