Convergence of the mass-transport steepest descent scheme for the sub-critical Patlak-Keller-Segel model

Variational steepest descent approximation schemes for the modified Patlak-Keller-Segel equation with a logarithmic interaction kernel in any dimension are considered. We prove the convergence of the suitably interpolated in time implicit Euler scheme, defined in terms of the Euclidean Wasserstein distance, associated to this equation for sub-critical masses. As a consequence, we recover the recent result about the global in time existence of weak-solutions to the modified Patlak-Keller-Segel equation for the logarithmic interaction kernel in any dimension in the sub-critical case. Moreover, we show how this method performs numerically in one dimension. In this particular case, this numerical scheme corresponds to a standard implicit Euler method for the pseudo-inverse of the cumulative distribution function. We demonstrate its capabilities to reproduce easily without the need of mesh-refinement the blow-up of solutions for super-critical masses.

A relative double commutant theorem for hereditary sub-C*-algebras

We prove a double commutant theorem for hereditary subalgebras of a large class of C*-algebras, partially resolving a problem posed by Pedersen[8]. Double commutant theorems originated with von Neumann, whose seminal result evolved into an entire field now called von Neumann algebra theory. Voiculescu proved a C*-algebraic double commutant theorem for separable subalgebras of the Calkin algebra. We prove a similar result for hereditary subalgebras which holds for arbitrary corona C*-algebras. (It is not clear how generally Voiculescu's double commutant theorem holds.)

La crisi sub-prime i el crack de 1929: Comparació d'episodis d'eufòria financera

Treball de recerca realitzat per un alumne d'ensenyament secundari i guardonat amb un Premi CIRIT per fomentar l'esperit científic del Jovent l'any 2009. La present investigació té per objecte d’estudi la relació, atès el període de turbulències econòmiques que travessa el món globalitzat, entre els episodis d’eufòria financera i les crisi financeres i econòmiques, i la periodicitat amb les que aquestes es produeixen. Aquesta pretén confrontar-se des d’una aproximació històric-econòmica, mitjançant l’anàlisi i la comparació de dos successos -el crack borsari de 1929 i la crisi sub-prime- per tal de demostrar la existència de comuns denominadors, i, a la llum dels resultats, apreciar les conclusions que aporta la Història. Serà, doncs, aquesta periodicitat i les seves implicacions la qual s'ambicionarà contrastar amb la realitat mitjançant l'aplicació i l'anàlisi pràctica de dos episodis rellevants i paradigmàtics, amb el recolzament i l'autoritat del model comparatiu establerts per l'economista John Kenneth Galbraith al seu llibre ''Breve historia de la euforia financiera''.

Mapping sub-flows to p2mp LSPs

In previous work we proposed a multi-objective traffic engineering scheme (MHDB-S model) using different distribution trees to multicast several flows. In this paper, we propose a heuristic algorithm to create multiple point-to-multipoint (p2mp) LSPs based on the optimum sub-flow values obtained with our MHDB-S model. Moreover, a general problem for supporting multicasting in MPLS networks is the lack of labels. To reduce the number of labels used, a label space reduction algorithm solution is also considered

A genomic analysis identifies a novel component in the genetic structure of sub-Saharan African populations

Studies of large sets of SNP data have proven to be a powerful tool in the analysis of the genetic structure of human populations. In this work, we analyze genotyping data for 2,841 SNPs in 12 Sub-Saharan African populations, including a previously unsampled region of south-eastern Africa (Mozambique). We show that robust results in a world-wide perspective can be obtained when analyzing only 1,000 SNPs. Our main results both confirm the results of previous studies, and show new and interesting features in Sub-Saharan African genetic complexity. There is a strong differentiation of Nilo-Saharans, much beyond what would be expected by geography. Hunter-gatherer populations (Khoisan and Pygmies) show a clear distinctiveness with very intrinsic Pygmy (and not only Khoisan) genetic features. Populations of the West Africa present an unexpected similarity among them, possibly the result of a population expansion. Finally, we find a strong differentiation of the south-eastern Bantu population from Mozambique, which suggests an assimilation of a pre-Bantu substrate by Bantu speakers in the region.

Catalan government popularity. An example of economic effects on sub-national government support

The aim of this essay is to deal with economic voting in contexts ofmultilevel governance and to be a contribution to the debate on attribution of responsibilities in popularity functions literature. We use aggregate and individual data from Catalonia in order to analyse the relation between the state of the economy and the support for a sub-state government. The empirical analysis shows that the responsibility hypothesis works in regional governments without explicit macroeconomic competencies. We have also considered the evaluations of government performance on certain specific policies in order to clarify and determine the factors that drive Catalan government support. The article considers the implications of the findings for future attempts to model party support in a context of the European Union.

International commodity prices, growth and the outbreak of Civil War in Sub-Saharan Africa

To learn more about the effect of economic conditions oncivil war, we examine whether Sub-Saharan civil wars aremore likely to start following downturns in the internationalprice of countries main export commodities. The data showa robust effect of commodity price downturns on the outbreakof civil wars. We also find that Sub-Saharan countries aremore likely to see civil wars following economic downturnsin their main OECD export destinations.

Fiscal decentralization policies and sub-national government debt in evolving federations

As part of a process of democratization, many countries spanning Europe, Latin Amertica, Africa, and Asia are reorganizing their governments bydevolving fiscal responsibility and authority to newly empowered regionaland local governments. Although decentralization in each country proceedsdifferently, a common element tends to be an initially heavy relianceon central government grants to fund regional spending. We develop atheoretical model of regional borrowing decisions in which the incentivesfor regional borrowing depend crucially on how the regions expect thefederal system of finance to evolve. We examine the implications of themodel using data on Spanish regions for the period 1984-1995 and findevidence that regions may be borrowing inefficiently in response toincentives imbedded in the Spanish system of fiscal decentralization.

Improving energy access in rural sub-Saharan Africa

XVII Convocatòria d’ajuts a accions de cooperació - 2009GRECDH – UPC. Improving Energy Access In Rural sub- Saharan Africa. O-006/09. Informe

Vortex state and effect of anisotropy in sub-100 nm magnetic nanodots

Magnetic properties of Fe nanodots are simulated using a scaling technique and Monte Carlo method, in good agreement with experimental results. For the 20-nm-thick dots with diameters larger than 60¿nm, the magnetization reversal via vortex state is observed. The role of magnetic interaction between dots in arrays in the reversal process is studied as a function of nanometric center-to-center distance. When this distance is more than twice the dot diameter, the interaction can be neglected and the magnetic properties of the entire array are determined by the magnetic configuration of the individual dots. The effect of crystalline anisotropy on the vortex state is investigated. For arrays of noninteracting dots, the anisotropy strongly affects the vortex nucleation field and coercivity, and only slightly affects the vortex annihilation field

Clinico-Pathological discrepancies in the Diagnosis of Causes of Maternal Death in Sub-Saharan Africa: Retrospective Analysis

Background Maternal mortality is a major public-health problem in developing countries. Extreme differences in maternal mortality rates between developed and developing countries indicate that most of these deaths are preventable. Most information on the causes of maternal death in these areas is based on clinical records and verbal autopsies. Clinical diagnostic errors may play a significant role in this problem and might also have major implications for the evaluation of current estimations of causes of maternal death. Methods and Findings A retrospective analysis of clinico-pathologic correlation was carried out, using necropsy as the gold standard for diagnosis. All maternal autopsies (n ¼ 139) during the period from October 2002 to December 2004 at the Maputo Central Hospital, Mozambique were included and major diagnostic discrepancies were analyzed (i.e., those involving the cause of death). Major diagnostic errors were detected in 56 (40.3%) maternal deaths. A high rate of false negative diagnoses was observed for infectious diseases, which showed sensitivities under 50%: HIV/AIDS-related conditions (33.3%), pyogenic bronchopneumonia (35.3%), pyogenic meningitis (40.0%), and puerperal septicemia (50.0%). Eclampsia, was the main source of false positive diagnoses, showing a low predictive positive value (42.9%). Conclusions Clinico-pathological discrepancies may have a significant impact on maternal mortality in sub-Saharan Africa and question the validity of reports based on clinical data or verbal autopsies. Increasing clinical awareness of the impact of obstetric and nonobstetric infections with their inclusion in the differential diagnosis, together with a thorough evaluation of cases clinically thought to be eclampsia, could have a significant impact on the reduction of maternal mortality.

Clinico-Pathological discrepancies in the Diagnosis of Causes of Maternal Death in Sub-Saharan Africa: Retrospective Analysis

Background Maternal mortality is a major public-health problem in developing countries. Extreme differences in maternal mortality rates between developed and developing countries indicate that most of these deaths are preventable. Most information on the causes of maternal death in these areas is based on clinical records and verbal autopsies. Clinical diagnostic errors may play a significant role in this problem and might also have major implications for the evaluation of current estimations of causes of maternal death. Methods and Findings A retrospective analysis of clinico-pathologic correlation was carried out, using necropsy as the gold standard for diagnosis. All maternal autopsies (n ¼ 139) during the period from October 2002 to December 2004 at the Maputo Central Hospital, Mozambique were included and major diagnostic discrepancies were analyzed (i.e., those involving the cause of death). Major diagnostic errors were detected in 56 (40.3%) maternal deaths. A high rate of false negative diagnoses was observed for infectious diseases, which showed sensitivities under 50%: HIV/AIDS-related conditions (33.3%), pyogenic bronchopneumonia (35.3%), pyogenic meningitis (40.0%), and puerperal septicemia (50.0%). Eclampsia, was the main source of false positive diagnoses, showing a low predictive positive value (42.9%). Conclusions Clinico-pathological discrepancies may have a significant impact on maternal mortality in sub-Saharan Africa and question the validity of reports based on clinical data or verbal autopsies. Increasing clinical awareness of the impact of obstetric and nonobstetric infections with their inclusion in the differential diagnosis, together with a thorough evaluation of cases clinically thought to be eclampsia, could have a significant impact on the reduction of maternal mortality.

Las entidades sub-nacionales en Norteamérica y la lucha contra el cambio climático: desarrollo normativo y vinculación de sistemas de comercio de derechos de emisión

[spa] Mientras que en Europa la interdependencia y la dimensión transfronteriza de las cuestiones ligadas al cambio climático ha facilitado una cierta"continentalización" de la gestión de este fenómeno, favorecida por el carácter intergubernamental de las medidas que se adoptan en el marco de la Unión Europea, al otro lado del Atlántico la transversalidad de este mismo fenómeno explica la necesidad de que, ante las limitaciones del marco regional, se pongan en marcha mecanismos que faciliten la intervención no sólo estatal sino también de las entidades sub-nacionales. En este sentido, la ausencia de la acción federal tanto en Estados Unidos como en Canadá ha comportado un mayor desarrollo de la acción de las entidades sub-nacionales, que han tomado el liderazgo en la lucha contra el cambio climático. Son estas medidas las que se han visualizado en el escenario internacional. Ello ha favorecido el establecimiento de mecanismos de coordinación de la acción de estas entidades sub-nacionales en el seno de redes transnacionales, que han ido adquiriendo una mayor relevancia en la implementación del Convenio Marco sobre el Cambio Climático y del Protocolo de Kyoto, particularmente en relación a uno de sus instrumentos, el comercio de los derechos de emisión de gases de efecto invernadero. En este contexto, la futura vinculación de los sistemas de comercio de derechos de emisión de gases de efecto invernadero en Norteamérica con el sistema de la Unión Europea presenta diversos retos de carácter material y formal.