A Characterization of single-peaked preferences

We identify in this paper two conditions that characterize the domain of single-peaked preferences on the line in the following sense: a preference profile satisfies these two properties if and only if there exists a linear order $L$ over the set of alternatives such that these preferences are single-peaked with respect L. The first property states that for any subset of alternatives the set of alternatives considered as the worst by all agents cannot contains more than 2 elements. The second property states that two agents cannot disagree on the relative ranking of two alternatives with respect to a third alternative but agree on the (relative) ranking of a fourth one. Classification-JEL: D71, C78

Corrigendum stable matchings and preferences of couples

We correct an omission in the definition of our domain of weakly responsive preferences introduced in Klaus and Klijn (2005) or KK05 for short. The proof of the existence of stable matchings (KK05, Theorem 3.3) and a maximal domain result (KK05, Theorem 3.5) are adjusted accordingly.

Approval voting ion dichotomous preferences

The aim of this paper is to find normative foundations of Approval Voting. In order to show that Approval Voting is the only social choice function that satisfies anonymity, neutrality, strategy-proofness and strict monotonicity we rely on an intermediate result which relates strategy-proofness of a social choice function to the properties of Independence of Irrelevant Alternatives and monotonicity of the corresponding social welfare function. Afterwards we characterize Approval Voting by means of strict symmetry, neutrality and strict monotonicity and relate this result to May's Theorem. Finally, we show that it is possible to substitute the property of strict monotonicity by the one efficiency of in the second characterization.

Scoring rules on dichotomous preferences

In this paper, we study individual incentives to report preferences truthfully for the special case when individuals have dichotomous preferences on the set of alternatives and preferences are aggregated in form of scoring rules. In particular, we show that (a) the Borda Count coincides with Approval Voting on the dichotomous preference domain, (b) the Borda Count is the only strategy-proof scoring rule on the dichotomous preference domain, and (c) if at least three individuals participate in the election, then the dichotomous preference domain is the unique maximal rich domain under which the Borda Count is strategy-proof.

A maximal domain of preferences for tops-only rules in the division problem

The division problem consists of allocating an amount M of a perfectly divisible good among a group of n agents. Sprumont (1991) showed that if agents have single-peaked preferences over their shares, the uniform rule is the unique strategy-proof, efficient, and anonymous rule. Ching and Serizawa (1998) extended this result by showing that the set of single-plateaued preferences is the largest domain, for all possible values of M, admitting a rule (the extended uniform rule) satisfying strategy-proofness, efficiency and symmetry. We identify, for each M and n, a maximal domain of preferences under which the extended uniform rule also satisfies the properties of strategy-proofness, efficiency, continuity, and "tops-onlyness". These domains (called weakly single-plateaued) are strictly larger than the set of single-plateaued preferences. However, their intersection, when M varies from zero to infinity, coincides with the set of single-plateaued preferences.

Corrigendum: stable matchings and preferences of couples

We correct an omission in the definition of the domain of weakly responsive preferences introduced in Klaus and Klijn (2005) or KK05 for short. The proof of the existence of stable matchings (KK05, Theorem 3.3) and a maximal domain result (KK05, Theorem 3.5) are adjusted accordingly.

Efficient and stable collective choices under gregarious preferences

We consider collective choice problems where a set of agents have to choose an alternative from a finite set and agents may or may not become users of the chosen alternative. An allocation is a pair given by the chosen alternative and the set of its users. Agents have gregarious preferences over allocations: given an allocation, they prefer that the set of users becomes larger. We require that the final allocation be efficient and stable (no agent can be forced to be a user and no agent who wants to be a user can be excluded). We propose a two-stage sequential mechanism whose unique subgame perfect equilibrium outcome is an efficient and stable allocation which also satisfies a maximal participation property.

Variabilitat temporal i geogràfica i caracterització química de la contaminació atmosfèrica particulada a Sabadell

Estudi de 3 punts amb diferent intensitat de trànsit a Sabadell: punt de trànsit, fons urbà i fons suburbà. Nivells de PM i altres gasos contaminants van ser mesurats durant 1 mes. Els objectius principals són la correlació dels nivells de partícules i NOx als 3 punts d’estudi (ja que als estudis epidemiològics s’utilitza NO2 com a indicador del nivell de partícules); la caracterització química de les partícules per determinar quina porció té origen en les emissions dels tubs d’escapament i identificar similituds i diferències entre els nivells i composició de partícules entre les diferents estacions seleccionades.

Spatio-temporal variations in reproductive patterns and population structure of Pasiphaea multidentata (Decapoda: Caridea) in the Blanes canyon and adjacent margin, North-western Mediterranean Sea

The bathyal faunal communities of the NW Mediterranean slopes have been studied consistently in the last two decades, with a special focus on population structure, trophic dynamics and benthopelagic coupling of commercial deep-sea decapod crustaceans and fishes (reviewed in Sardà et al. 2004) and associated species (Cartes and Sardà, 1993; Company and Sardà, 1997, 2000; Cartes et al., 2001; Company et al., 2001, 2003, 2004). One of the major topographic features in the North-western Mediterranean slope is the presence of submarine canyons. Canyons play a major role in funnelling energy and organic matter from the shelf to bathyal and abyssal depths (Puig et al., 2000), but the implications of this enhanced organic supply in the deep-sea benthic communities is still mostly unknown. Trophic supply can follow two major pathways – vertical deposition in the water column (Billett et al., 1983; Baldwin et al., 1998; Lampitt et al., 2001) or down-slope advection on the margins (Puig et al., 2001; Bethoux et al., 2002; Canals et al., 2006) – and can be a limiting factor in the deep-sea, being especially important in the oligotrophic Mediterranean Sea (Sardà et al., 2004). Differences in the quantity, quality and timing of organic matter input to the deep seafloor have been used to explain patterns of biomass and abundance in benthic communities (Levin et al., 1994; Gooday & Turley, 1990; Billett et al., 2001; Galéron et al., 2001; Puig et al., 2001; Gage, 2003) as well as other biological process and in particular the existence of seasonal reproduction (Tyler et al., 1994; Company et al., 2004 (MEPS). Reproduction is a highly energetic process tightly linked to food availability and quality.

Gérard Grisey : la cuantificación temporal deducida de los procesos perceptivos

En el presente trabajo, tratamos diferentes perspectivas sobre la poética, estrategias compositivas y repercusión perceptiva del tiempo en la música de Gérard Grisey. En el primer capítulo, abordamos la concepción del tiempo como unidad y proporcionalidad duracional y su relación con otros parámetros musicales. A continuación, presentamos tres enfoques sobre el tiempo que emergen de la poética de Grisey y del análisis de sus obras: la ruptura con la proporcionalidad duracional y la relación entre tiempo y sonido, el concepto de cambio de escala temporal y la analogía entre tiempo y cosmos. En el segundo capítulo, proponemos tres categorías temporales basadas principalmente en el concepto de previsibilidad: tiempo no lineal, tiempo lineal y tiempo procesual. En el tercer y último capítulo, exponemos los fundamentos de la Teoría de la Información, su relación con el discurso de Grisey y su método de aplicación.

Degeneració Lobular Fronto-Temporal. Fenotips Clínics i Evolució

Estudi retrospectiu de recollida de dades clíniques i de neuroimatge de pacients diagnosticats, em La clínica diària, de Degeneració Lobular Fronto-Temporal (DLFT) entre gener de 1996 i Marc de 2008. Es descriuen dades demogràfiques i clíniques i es classifiquen en fenotips al diagnòstic inicial segons variants de: DFT-vc (Demència fronto-temporal variant de conducta), APNF (Afàsia Progressiva no fluent) DS (Demència Semàntica) SCB (Síndrome Còrtico-Basal) y PSP (Paràlisis Supranuclear Progressiva). Es descriuen els canvis clínics durant el seguiment i s’analitzen els patrons radiològics en les neuroimatges disponibles. S’inclouen també dades d’ApoE i l’estudi anatomopatològic realitzat a 17 d’ells.

A la llum de les matrius: projecte d'exposició temporal

El treball presenta el projecte d'una exposició temporal al Museu d'Art sobre el fons de xilografies procedents de la Impremta Carreras

Variació temporal de paràmetres de qualitat del sòl ocasionada per l’ús i abandó agrícola del Cap de Creus

Estudi i avaluació de les principals propietats del sòl i la dinàmica erosiva relacionades amb l’ús del sòl i l’abandó agrícola en diferents ambients de la península del Cap de Creus. Per dur a terme aquest estudi s’han seleccionat 7 ambients diferentsrepresentatius d’una seqüència d’usos fins l’abandó en diferents etapes desuccessió vegetal. Els ambients són diferenciats entre sòls cultivats (vinya iolivera), sòls forestals (sureda i pineda), pastures (prats) i matollars (Cistusmonspeliensis i d’Erica arborea) respectivament cremat reiteradament i nocremat durant 25 anys. En cada ambient s’han instal.lat parcel.les d’erosióque permeten avaluar la producció de sediments i la mobilització de nutrients (carboni i nitrogen) durant els episodis de precipitació que generen escolament superficial