Local and global consistency properties for student placement

In the context of resource allocation on the basis of priorities, Ergin (2002) identifies a necessary and sufficient condition on the priority structure such that the student-optimal stable mechanism satisfies a consistency principle. Ergin (2002) formulates consistency as a local property based on a fixed population of agents and fixed resources -- we refer to this condition as local consistency and to his condition on the priority structure as local acyclicity. We identify a related but stronger necessary and sufficient condition (unit acyclicity) on the priority structure such that the student-optimal stable mechanism satisfies a more standard global consistency property. Next, we provide necessary and sufficient conditions for the student-optimal stable mechanism to satisfy converse consistency principles. We identify a necessary and sufficient condition (local shift-freeness) on the priority structure such that the student-optimal stable mechanism satisfies local converse consistency. Interestingly, local acyclicity implies local shift-freeness and hence the student-optimal stable mechanism more frequently satisfies local converse consistency than local consistency. Finally, in order for the student-optimal stable mechanism to be globally conversely consistent, one again has to impose unit acyclicity on the priority structure. Hence, unit acyclicity is a necessary and sufficient condition on the priority structure for the student-optimal stable mechanism to satisfy global consistency or global converse consistency.

Optimal coexistence of long-term and short-term contracts in labor Markets

We consider a market where firms hire workers to run their projects and such projects differ in profitability. At any period, each firm needs two workers to successfully run its project: a junior agent, with no specific skills, and a senior worker, whose effort is not verifiable. Senior workers differ in ability and their competence is revealed after they have worked as juniors in the market. We study the length of the contractual relationships between firms and workers in an environment where the matching between firms and workers is the result of market interaction. We show that, despite in a one-firm-one-worker set-up long-term contracts are the optimal choice for firms, market forces often induce firms to use short-term contracts. Unless the market only consists of firms with very profitable projects, firms operating highly profitable projects offer short-term contracts to ensure the service of high-ability workers and those with less lucrative projects also use short-term contracts to save on the junior workers' wage. Intermediate firms may (or may not) hire workers through long-term contracts.

Nivell global d'estrès en pares i mares de fills diagnosticats amb trastorn del desenvolupament en les primeres etapes evolutives

Aquest treball és un estudi descriptiu centralitzat en una població concreta i en un moment concret. La investigació estudia el nivell d’estrès global que tenen els pares i les mares de fills/es amb un trastorn del seu desenvolupament en les seves primeres edats maduratives i com afronten aquest procés. S’han estudiat pares i mares de nens i nenes d’entre 2 i 6 anys d’edat i que han estat atesos en el Centre de Desenvolupament Infantil d’Atenció Precoç (CDIAP) Tris-Tras de Vic (Barcelona).

The global uranium rush and its Africa frontier. Lessons from Namibia

Uranium mines are the - often forgotten - source of nuclear power. The promotion of nuclear energy as a clean alternative and the projected increase of electricity demand in countries such as China and India, have led to a global “uranium rush”, unseen since the peak of the Cold War. This article studies the formation of the expanding nuclear frontier looking at the interaction between the global uranium metabolism, industrial dynamics and local ecologies of resistance using Namibia as a case-study. Namibia, the world´s fourth largest producer of uranium, stands at the frontier of this rush with sixty-six recently granted prospecting licenses that could turn into mines, compared to only three currently operating mines. We focus on three generic attributes that help to explain the emergence and intensity of resistance by local communities to uranium mining: the ecology and geography of the resource; the degree and type of political and economic marginalization of the community; and crucially, the connection and integration of local concerns with broader social movements and political demands. We show with the use of empirical material how these factors play out differently in five Namibian communities that have been, or stand to be, affected by uranium mining, and explain how local ecologies of resistance shape the global uranium rush.

Impacto del seguimiento del cáncer de vejiga en la supervivencia global y el intervalo libre de enfermedad.

Comprovar en una sèrie de més de 300 pacients tractats amb intenció radical de càncer de bufeta si el seguiment que se´ls realitza de manera rutinària permet la detecció precoç de les recaigudes i té un impacte positiu en la seva supervivencia i l´interval lliure de malaltia.

Driving competition in local gasoline markets

Relevant market definition is still a key element of economic analysis of competition in the gasoline market. It is particularly difficult to handle when competition is local and market power is geographically constrained like is the case in the gasoline market. We analyse how the application of the hypothetical monopolist or Small but Significant Non-Transitory Increase in Prices (SSNIP) test performs for defining isochrones using only information on prices and distance among competitors. We conclude that geographic information systems can be very successfully used to define more precisely relevant geographic market in the gasoline retailing. The application to the Spanish gasoline market concludes that geographic relevant market is composed by 5-6 minutes of travel time. Localised market power should be taken into account when analysing the adverse effects of mergers and entry regulations in gasoline retailing. Only drawing small enough isochrones will drive competition in local markets because it is just close rivals that compete effectively with each other.

Implicaciones socioeconómicas de las redes sociales en el mundo global

Avui dia les xarxes socials, gràcies a les noves tecnologies, han generat un canvi en la filosofia de la comunicació on Internet s’utilitza tan per rebre informació com per difondre-la. Aquest canvi té una repercussió no només pel que fa a les relacions personals, sinó que també s’han experimentat en el sector de la publicitat modificacions de les seves estratègies i de la planificació de pressupostos. El món puja a aquest nou tren on tot està connectat. De la mà dels teòrics de la informació i gràcies a estudis sobre l’ús de les noves tecnologies hem aconseguit extreure perfils d’usuaris i plasmar reflexes d’aquesta nova “societat virtual” que té un impacte en la economia global.

Accounting for Big City Growth in Low Paid Occupations: Immigration and/or Service Class Consumption

Growth of 'global cities' in the 1980s was supposed to have involved an occupational polarisation, including growth of low paid service jobs. Though held to be untrue for European cities, at the time, some such growth did emerge in London a decade later than first reported for New York. The question is whether there was simply a delay before London conformed to the global city model, or whether another distinct cause was at work in both cases. This paper proposes that the critical factor in both cases was actually an upsurge of immigration from poor countries providing an elastic supply of cheap labour. This hypothesis and its counterpart based on growth in elite jobs are tested econometrically for the British case with regional data spanning 1975-2008, finding some support for both effects, but with immigration from poor countries as the crucial influence in late 1990s London. Keywords: regional labour markets; wages; employment; international migration; consumer demand JEL Codes: J21, J23, F22, R12

Solució global per la gestió de dades d'empleat mitjançant J2ME/J2EE.

Aquest treball final de carrera es basa en l'anàlisi, disseny i implementació d'una solució per comunicar un empleat i la seva empresa per tal de gestionar informació i dades de l'empleat com poden ser: la nòmina, el full d'hores, el full de despeses i la consulta i sol·licitud de vacances.

Espai Global del Coneixement : Desenvolupament d'una aplicació amb arquitectura J2EE

En els següents punts d'aquest document, es tractaran amb detall tots els aspectes de les etapes d'anàlisi i disseny, per a finalment poder dur a terme una conclusió i una anàlisi dels resultats obtinguts.

VoWiFi & IM : Comunicaciones móviles en la red global

El principal objectiu d'aquest projecte és l'estudi de la tecnologia ViWiFi tant des del punt de vista de la seva base tècnica com de les seves possibles aplicacions actuals i futures, especialment referent a la integració de serveis addicionals com la missatgeria instantània. Una vegada analitzats els conceptes teòrics es realitza un estudi de les principals eines de codi obert que permeten implementar aquest tipus de plataformes, per a finalment concloure amb la instal·lació pràctica d'una plataforma de laboratori.

Informatitzar l'escola : projecte global d'informatització d'un centre escolar

En el moment actual la presència de la tecnologia de la informació i la comunicació (TIC) es fa imprescindible en les activitats de la vida quotidiana. En l'escola d'una societat moderna està adquirint una presència transcendental i inqüestionable que està canviant les formes d'aprendre i transmetre els coneixements. L'escola millor preparada serà aquella que dispose d'aules autosuficients, és a dir aules en què es troben els recursos tecnològics necessaris per a possibilitar a l'alumnat l'accés a la informació i a la comunicació que ens proporciona la xarxa i els sistemes de presentació multimèdia disponibles en estos temps. La informàtica, Internet, el vídeo, la televisió, i els mitjans per a audicions i projeccions són necessitats que tant l'alumnat com el professorat han de tindre al seu abast en tot moment. Cada vegada més la majoria de les activitats que es realitzen en l'escola necessiten utilitzar estes tecnologies.

Innovation strategies in the presence of technology markets: evidence from spanish innovative firms

The development of markets for technology has eased the acquisition of technology and reshaped the innovation strategies of firms that we classify as producers of innovations or as imitators. Innovative activities of firms include research, acquisition of technology and downstream activities. Within an industry, firms producing innovations tend to conduct more research and downstream activities than those imitating innovations. Acquisition of technology is equally important for both. To implement innovation strategies, firms producing innovations require both the capability to scan the external environment for technology and the capability to integrate new technology. Firms producing innovations require both, while firms imitating innovations require scan capabilities only

Large-Area Photo-Mosaics Using Global Alignment and Navigation Data

Seafloor imagery is a rich source of data for the study of biological and geological processes. Among several applications, still images of the ocean floor can be used to build image composites referred to as photo-mosaics. Photo-mosaics provide a wide-area visual representation of the benthos, and enable applications as diverse as geological surveys, mapping and detection of temporal changes in the morphology of biodiversity. We present an approach for creating globally aligned photo-mosaics using 3D position estimates provided by navigation sensors available in deep water surveys. Without image registration, such navigation data does not provide enough accuracy to produce useful composite images. Results from a challenging data set of the Lucky Strike vent field at the Mid Atlantic Ridge are reported