1,968 research outputs found
Creation of public use files: lessons learned from the comparative effectiveness research public use files data pilot project
In this paper we describe lessons learned from the creation of Basic Stand Alone (BSA) Public Use Files (PUFs) for the Comparative Effectiveness Research Public Use Files Data Pilot Project (CER-PUF). CER-PUF is aimed at increasing access to the Centers for Medicare and Medicaid Services (CMS) Medicare claims datasets through PUFs that: do not require user fees and data use agreements, have been de-identified to assure the confidentiality of the beneficiaries and providers, and still provide substantial analytic utility to researchers. For this paper we define PUFs as datasets characterized by free and unrestricted access to any user. We derive lessons learned from five major project activities: (i) a review of the statistical and computer science literature on best practices in PUF creation, (ii) interviews with comparative effectiveness researchers to assess their data needs, (iii) case studies of PUF initiatives in the United States, (iv) interviews with stakeholders to identify the most salient issues regarding making microdata publicly available, and (v) the actual process of creating the Medicare claims data BSA PUFs
Parabolic Higgs bundles and representations of the fundamental group of a punctured surface into a real group
We study parabolic G-Higgs bundles over a compact Riemann surface with fixed
punctures, when G is a real reductive Lie group, and establish a correspondence
between these objects and representations of the fundamental group of the
punctured surface in G with arbitrary holonomy around the punctures. Three
interesting features are the relation between the parabolic degree and the
geometry of the Tits boundary, the treatment of the case when the logarithm of
the monodromy is on the boundary of a Weyl alcove, and the correspondence of
the orbits encoding the singularity via the Kostant-Sekiguchi correspondence.
We also describe some special features of the moduli spaces when G is a split
real form or a group of Hermitian type.Comment: v2: references added, a few typos corrected; v3: substantial
revision, added three sections: (3) relation to parahoric bundles, (7) moduli
spaces, (8) examples, 60 pages; v4: several corrections, more details
included on the Hitchin-Kobayashi correspondence, some proofs shortened, 57
page
Higgs bundles and surface group representations in the real symplectic group
In this paper we study the moduli space of representations of a surface group
(i.e., the fundamental group of a closed oriented surface) in the real
symplectic group Sp(2n,R). The moduli space is partitioned by an integer
invariant, called the Toledo invariant. This invariant is bounded by a
Milnor-Wood type inequality. Our main result is a count of the number of
connected components of the moduli space of maximal representations, i.e.
representations with maximal Toledo invariant. Our approach uses the
non-abelian Hodge theory correspondence proved in a companion paper
arXiv:0909.4487 [math.DG] to identify the space of representations with the
moduli space of polystable Sp(2n,R)-Higgs bundles. A key step is provided by
the discovery of new discrete invariants of maximal representations. These new
invariants arise from an identification, in the maximal case, of the moduli
space of Sp(2n,R)-Higgs bundles with a moduli space of twisted Higgs bundles
for the group GL(n,R).Comment: 55 pages; v2: main results are unchanged but paper has been
completely reorganized and presentation significantly improved; v3, v4:
various corrections and improvements; Part 1 of v2 has been split off as the
independent paper arXiv:0909.4487v1 [math.DG
La imagen de los soldados italianos en Cataluña en la guerra del francés
El articulo analiza la imagen, actuación y características de los soldados de origen italiano integrados en el ejercito formado por Napoleón para invadir a España durante la Guerra del Francés. Entre otras fuentes, el autor del artículo se remite a los escritos coetanios de Gabriele Pepe o del padre Raimundo Ferrer, vicario de la parroquia de Sant Just i Pastor, o las fuentes oficiales como la Gazeta militar y política del Principado de Cataluña o la Gazeta de Vic.L'article analitza la imatge, actuació i característiques dels soldats d'origen Italia integrats dins l'exèrcit alienat per Napoleó per envair Espanya durant la Guerra del Francés. Entre d'altres fonts, l'autor empra els escrits de Gabriele Pepe o el pare Raimon Ferrer, vicari de la parroquia de Sant Just i Pastor, o les fonts oficials com la Gazeta militar y política del Principado de Cataluña o la Gazeta de Vic.The article focus on italian soldiers on Napoleon army during French War in Catalonia
Ressenyes
Obra ressenyada: Quintí CASALS BERGÉS, La guerra del Francès a Catalunya: una nòmina del seu poder polític (1808-1814). Lleida: Institut d'Estudis Ilerdencs. Diputació de Lleida, 2016
Reseñas
Obra ressenyada: Tereza CAILLAUX DE ALMEIDA. Memória das «Invasôes Francesas» em Portugal. Una perspectiva innovadora no bicentenário da Guerra Peninsular. Lisboa : Ésquilo, 2010
Using synchronization to improve earthquake forecasting in a cellular automaton model
A new forecasting strategy for stochastic systems is introduced. It is
inspired by the concept of anticipated synchronization between pairs of chaotic
oscillators, recently developed in the area of Dynamical Systems, and by the
earthquake forecasting algorithms in which different pattern recognition
functions are used for identifying seismic premonitory phenomena. In the new
strategy, copies (clones) of the original system (the master) are defined, and
they are driven using rules that tend to synchronize them with the master
dynamics. The observation of definite patterns in the state of the clones is
the signal for connecting an alarm in the original system that efficiently
marks the impending occurrence of a catastrophic event. The power of this
method is quantitatively illustrated by forecasting the occurrence of
characteristic earthquakes in the so-called Minimalist Model.Comment: 4 pages, 3 figure
Popular resistence in catalonia: somatenes and migueletes in the french war
The author treats the characteristics of the somatenes and the miquelets during the Great War (1793-95) and the French War (1808-1814), he impacts in the strategies of the formation, the problem of the desertions, the profile of the war of guerrilla warfare and the activities of the irregular forces in relation to the military authorities.L'autor tracta les característiques dels somatens i els miquelets durant la Gran Guerra (1793-95) i la Guerra del francès (1808-1814) fent incidència en les estratègies de formació, el problema de les desercions, el perfil de la guerra de guerrilles i les activitats de les forces irregulars en relació amb les autoritats militars
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