The orthogonal subcategory problem in homotopy theory

It is known that, in a locally presentable category, localization exists with respect to every set of morphisms, while the statement that localization with respect to every (possibly proper) class of morphisms exists in locally presentable categories is equivalent to a large-cardinal axiom from set theory. One proves similarly, on one hand, that homotopy localization exists with respect to sets of maps in every cofibrantly generated, left proper, simplicial model category M whose underlying category is locally presentable. On the other hand, as we show in this article, the existence of localization with respect to possibly proper classes of maps in a model category M satisfying the above assumptions is implied by a large-cardinal axiom called Vopënka's principle, although we do not know if the reverse implication holds. We also show that, under the same assumptions on M, every endofunctor of M that is idempotent up to homotopy is equivalent to localization with respect to some class S of maps, and if Vopënka's principle holds then S can be chosen to be a set. There are examples showing that the latter need not be true if M is not cofibrantly generated. The above assumptions on M are satisfied by simplicial sets and symmetric spectra over simplicial sets, among many other model categories.

A note on parallelizing the parameterized expectations algorithm

The parameterized expectations algorithm (PEA) involves a long simulation and a nonlinear least squares (NLS) fit, both embedded in a loop. Both steps are natural candidates for parallelization. This note shows that parallelization can lead to important speedups for the PEA. I provide example code for a simple model that can serve as a template for parallelization of more interesting models, as well as a download link for an image of a bootable CD that allows creation of a cluster and execution of the example code in minutes, with no need to install any software.

Desenvolupament d'aplicacions amb J2EE

Aquest document es un resum del Treball Final de Carrera de l'àrea tècnica J2EE

When a data set can be considered compositional?

Traditionally, compositional data has been identified with closed data, and the simplex has been considered as the natural sample space of this kind of data. In our opinion, the emphasis on the constrained nature ofcompositional data has contributed to mask its real nature. More crucial than the constraining property of compositional data is the scale-invariant property of this kind of data. Indeed, when we are considering only few parts of a full composition we are not working with constrained data but our data are still compositional. We believe that it is necessary to give a more precisedefinition of composition. This is the aim of this oral contribution

La storia del diritto privato e l’organizzazione giuridica nell’antica Persia

Il sottoscritto lavoro e ricerca è risultato di circa tre anni di ricerche presso l’Università autonoma di Barcellona ed altre università europee ed iraniane. Il tema della ricerca s’intitola “La storia del Diritto Privato e l’organizzazione giuridica nell’antica Persia” ed è stato realizzato con la gentile direzione della Professoressa Gete Alonso, cattedratica di Diritto Civile presso l’Università Autonoma di Barcellona. In questo lavoro si è parlato maggiormente di due dinastie principali dell’era antica persiana ovvero la dinastia degli achemenide ed i sassani , ovvero un periodo di tempo tra l’anno 550 a.c. ed il 651 d.c. in qui fu il culmine dell’evoluzione storica e giuridica iraniana nell’antica Persia che va a sostituirsi con l’attacco e l’invasione araba e l’inizio dell’era islamica. Questo studio ci offre una base adatta ad effettuare di un lato uno studio comparato tra un sistema giuridico mediorientale antico con altri sistemi giuridici vigenti al tempo nel mondo come l’antica Babilinia, Grecia e Roma e d'altronde creare una base per confrontare il diritto antico applicato in Persia con il diritto attuale applicato nella Repubblica Islamica dell’Iran e quindi proporre una base di studio comparato nel tempo e tra vari sistemi giuridici antichi. Spero tanto che questa ricerca possa essere utile agli studiosi interessati a conoscere vari sistemi giuridici per poi confrontarli con altri sistemi antichi ed oggigiorno vigenti in modo tale di poter migliorare giorno dopo giorno le idee giuridiche applicabili nei vari sistemi attuali.

Review of the literature on reference pricing

This paper reviews the literature on reference pricing (RP) in pharmaceutical markets. The RP strategy for cost containment of expenditure on drugs is analyzed as part of the procurement mechanism. We review the existing literature and the state-of-the-art regarding RP by focusing on its economic effects. In particular, we consider: (1) the institutional context and problem-related factors which appear to underline the need to implement an RP strategy; i.e., its nature, characteristics and the sort of health care problems commonly addressed; (2) how RP operates in practice; that is, how third party-payers (the insurers/buyers) have established the RP systems existing on the international scene (i.e., information methods, monitoring procedures and legislative provisions); (3)the range of effects resulting from particular RP strategies (including effects on choice of appropriate pharmaceuticals, insurer savings, total drug expenditures, prices of referenced and non-referenced products and dynamic efficiency; (4) the market failures which an RP policy is supposed to address and the main advantages and drawbacks which emerge from an analysis of its effects. Results suggest that RP systems achieve better their postulated goals (1) if cost inflation in pharmaceuticals is due to high prices rather than to the excess of prescription rates, (2) when the larger is the existing difference in prices among equivalent drugs, and (3) more important is the actual market for generics.

Asociaciones entre la red social y la discapacidad al comienzo de la vejez en las ciudades de Madrid y Barcelona en 2005

La pérdida de autonomía a edades avanzadas no se asocia únicamente con el envejecimiento sino también con características del entorno físico y social. Investigaciones recientes han demostrado que la red social, la integración social y la participación, actúan como predictores de la discapacidad en la vejez. El objetivo de este trabajo es nalizar el efecto de la red social sobre el nivel de autonomía(en términos de discapacidad instrumental y básica) en etapas iniciales de la vejez.