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Search Results: 1 - 10 of 557 matches for " Paloma Cariello "
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Completely Reducible maps in Quantum Information Theory
Daniel Cariello
Physics , 2014,
Abstract: In order to compute the Schmidt decomposition of $A\in M_k\otimes M_m$, we must consider an associated self-adjoint map. Here, we show that if $A$ is positive under partial transposition (PPT) or symmetric with positive coefficients (SPC) or invariant under realignment then its associated self-adjoint map is completely reducible. We give applications of this fact in Quantum Information Theory. We recover some theorems recently proved for PPT and SPC matrices and we prove these theorems for matrices invariant under realignment using theorems of Perron-Frobenius theory. We also provide a new proof of the fact that if $\mathbb{C}^{k}$ contains $k$ mutually unbiased bases then $\mathbb{C}^{k}$ contains $k+1$. We search for other types of matrices that could have the same property. We consider a group of linear transformations acting on $M_k\otimes M_k$, which contains the partial transpositions and the realignment map. For each element of this group, we consider the set of matrices in $M_k\otimes M_k\simeq M_{k^2}$ that are positive and remain positive, or invariant, under the action of this element. Within this family of sets, we have the set of PPT matrices, the set of SPC matrices and the set of matrices invariant under realignment. We show that these three sets are the only sets of this family such that the associated self-adjoint map of each matrix is completely reducible. We also show that every matrix invariant under realignment is PPT in $M_2\otimes M_2$ and we present a counterexample in $M_k\otimes M_k$, $k\geq 3$.
Does Symmetry Imply PPT Property?
Daniel Cariello
Physics , 2014,
Abstract: Recently, in [1], the author proved that many results that are true for PPT matrices also hold for another class of matrices with a certain symmetry in their Hermitian Schmidt decompositions. These matrices were called SPC in [1] (definition 1.1). Before that, in [9], T\'oth and G\"uhne proved that if a state is symmetric then it is PPT if and only if it is SPC. A natural question appeared: What is the connection between SPC matrices and PPT matrices? Is every SPC matrix PPT? Here we show that every SPC matrix is PPT in $M_2\otimes M_2$ (theorem 4.3). This theorem is a consequence of the fact that every density matrix in $M_2\otimes M_m$, with tensor rank smaller or equal to 3, is separable (theorem 3.2). This theorem is a generalization of the same result found in [1] for tensor rank 2 matrices in $M_k\otimes M_m$. Although, in $M_3\otimes M_3$, there exists a SPC matrix with tensor rank 3 that is not PPT (proposition 5.2). We shall also provide a non trivial example of a family of matrices in $M_k\otimes M_k$, in which both, the SPC and PPT properties, are equivalent (proposition 6.2). Within this family, there exists a non trivial subfamily in which the SPC property is equivalent to separability (proposition 6.4).
Separability for Weak Irreducible matrices
Daniel Cariello
Physics , 2013,
Abstract: This paper is devoted to the study of the separability problem in the field of Quantum information theory. We deal mainly with the bipartite finite dimensional case and with two types of matrices, one of them being the PPT matrices. We proved that many results holds for both types. If these matrices have specific Hermitian Schmidt decompositions then the matrices are separable in a very strong sense. We proved that both types have what we call split decompositions. We defined the notion of weak irreducible matrix, based on the concept of irreducible state defined recently. These split decomposition theorems together with the notion of weak irreducible matrix, imply that these matrices are weak irreducible or a sum of weak irreducible matrices of the same type. The separability problem for these types of matrices can be reduced to the set of weak irreducible matrices of the same type. We also provided a complete description of weak irreducible matrices of both types. Using the fact that every positive semidefinite Hermitian matrix with tensor rank 2 is separable, we found sharp inequalites providing separability for both types.
Performance of six severity-of-illness scores in cancer patients requiring admission to the intensive care unit: a prospective observational study
Márcio Soares, Flávia Fontes, Joana Dantas, Daniela Gadelha, Paloma Cariello, Flávia Nardes, César Amorim, Luisa Toscano, José R Rocco
Critical Care , 2004, DOI: 10.1186/cc2870
Abstract: A prospective observational cohort study was performed in an oncological medical/surgical ICU in a Brazilian cancer centre. Data were collected over the first 24 hours of ICU stay. Discrimination was assessed by area under the receiver operating characteristic curves and calibration was done using Hosmer–Lemeshow goodness-of-fit H-tests.A total of 1257 consecutive patients were included over a 39-month period, and 715 (56.9%) were scheduled surgical patients. The observed hospital mortality was 28.6%. Two performance analyses were carried out: in the first analysis all patients were studied; and in the second, scheduled surgical patients were excluded in order to better compare CMM and general prognostic scores. The results of the two analyses were similar. Discrimination was good for all of the six studied models and best for Simplified Acute Physiology Score II and Acute Physiology and Chronic Health Evaluation III-J. However, calibration was uniformly insufficient (P < 0.001). General scores significantly underestimated mortality (in comparison with the observed mortality); this was in contrast to the CMM, which tended to overestimate mortality.None of the model scores accurately predicted outcome in the present group of critically ill cancer patients. In addition, there was no advantage of CMM over the other general models.Advances in oncological and supportive care have improved survival rates in cancer patients to the point that many of them can now be cured or have their disease controlled. However, such advances have often been achieved through aggressive therapies and support, at high expense [1]. Some of these patients require admission to the intensive care unit (ICU) for acute concurrent illness, postoperative care, or complications of their cancer or its therapy [2]. In general hospitals, intensivists frequently consider these patients as having a poor prognosis and tend to oppose their admission to the ICU [3]. Recent studies [4,5] have indicated that
BIZERRIL, José - O retorno à raiz: uma linhagem taoísta no Brasil
Maria Regina Cariello Moraes
REVER : Revista de Estudos da Religi?o , 2008,
Abstract:
A cor na obra de Donald Judd: intera??o entre matéria e luz
Carvalho, Paloma;
ARS (S?o Paulo) , 2009, DOI: 10.1590/S1678-53202009000100009
Abstract: we try to make visible how the light that touches and propagates over donald judd′s pieces-its internal and external surfaces-was conceived by the artist in the same way as the physical structure of these. in donald judd's work, color turns into a synonym of material surface. it's inherent, substantive, non-applied and without metaphorical meanings. we are following the recent critical tendency that sees a new concept of color in donald judd's work that until some years ago was taken as an orthodox minimalist leader, far away from any appeal to the senses.
Memória em desconstru??o: da ditadura à pós-ditadura
Vidal, Paloma;
Alea : Estudos Neolatinos , 2006, DOI: 10.1590/S1517-106X2006000200007
Abstract: how do we narrate horror? how do we construct a memory of horror? the first question unfolds into the second when we go from dictatorship to postdictatorship, as we may see in the narratives of argentine writer rodolfo enrique fogwill. through the analysis of two of the author's short stories, "muchacha punk" (1979) and "la larga risa de todos estos a?os" (1983), this article examines the way in which his narratives operate a shift in relation to the notion of testimony, in order to narrate the horrors of dictatorship, as well as in relation to the construction of memory, as they point out its inevitably faulty character. with these shifts fogwill displays the nation's fissures and deconstructs its myths.
Antracología y métodos: implicaciones en la economía prehistórica, etnoarqueología y paleoecología
Uzquiano, Paloma
Trabajos de Prehistoria , 1997,
Abstract: This paper concerns Anthracology (Charcoal analysis) from archaeological deposits. The methodology of study is discussed in detail. From sampling of charcoals in the site until their interpretation at the laboratory, this discipline has many implications in different areas both of the Earth Sciences and the Historical Sciences (Palaeoecology, Palaeoeconomy, Palaeoethnology). Se define la Antracología aplicada a la Arqueología exponiendo detalladamente todas las etapas que constituyen su metodología de estudio. Desde la recogida de carbones en el yacimiento hasta la interpretación de los resultados en el laboratorio, esta disciplina ha revelado las múltiples implicaciones en áreas diversas de las Ciencias de la Tierra (Paleoecología) y de las Ciencias Históricas (Economía y Etnología prehistóricas).
Cádiz y el comercio de productos griegos en Andalucía Occidental durante los siglos V y IV a.C.
Cabrera, Paloma
Trabajos de Prehistoria , 1994,
Abstract: We examined in this paper the process of gaditain trade system development during the 5th and 4th centuries b.C., trough the study of greek imports. This process is studied from a mediterranean perspective, within the framework of core-periphery interactions established between Eastern and Central Mediterranean and the South of the Iberian Peninsula. Emporion and Ebusus played a prominent role in these interactions. We suggest that this trade system configuration contributed to the economic development of Tudetania, which took part in an economic world system through Cadiz, and whose motors were Athens and Carthage. Analizamos en este articulo el proceso de desarrollo del sistema comercial gaditano durante los siglos V y IV a.C. a través del estudio de las importaciones griegas. El trabajo se aborda desde una perspectiva mediterránea, dentro del marco de las relaciones centro-periferia establecidas entre el Mediterráneo oriental y central y el Sur de la Península Ibérica. Ampurias e Ibiza jugaron un papel fundamental en estas relaciones. Se propone que la configuración de este sistema comercial contribuyó decisivamente al desarrollo económico de la Turdetania, que se sumerge a través de Cádiz en un sistema económico mundial, cuyos grandes motores serán Atenas y Cartago.
Jueces, represión y justicia transicional en Espa a, Chile y Argentina
Aguilar, Paloma
Revista Internacional de Sociologia , 2013,
Abstract: Why have some democracies made considerable progress in elucidating and prosecuting human rights violations committed by preceding dictatorships, while others still have amnesty laws that prevent —or at least hinder— the approval of such policies? We aim to demonstrate that, during democratization periods, the more legal the previous dictatorial repression, and the more direct judicial involvement in it, the more resistance there will be to apply policies of transitional justice. We will compare the Spanish case with those of Chile and Argentina. The establishment of democracy following a right-wing dictatorship responsible for the systematic violation of human rights forced all three countries to consider how best to confront this violent past. Once democracy has been consolidated, additional explanatory factors will account for the presence or absence of judicial accountability. Por qué algunas democracias han avanzado tanto en el esclarecimiento y la persecución judicial de las violaciones de derechos humanos cometidas por las dictaduras precedentes, mientras que otras mantienen vigentes leyes de amnistía que impiden —o, al menos, dificultan— la aprobación de dichas medidas? Nos proponemos demostrar que, durante los procesos de democratización, cuanto más “legal” haya sido la represión dictatorial, y mayor sea la implicación de los jueces en ella, mayor resistencia existirá a la aplicación de políticas de justicia transicional. Nos proponemos comparar el caso espa ol con el chileno y el argentino. En los tres países hubo dictaduras de corte conservador, la violación de derechos humanos fue sistemática y, cuando se democratizaron, tuvieron que reflexionar sobre qué hacer con este pasado de violencia política. Una vez que la democracia se ha consolidado, factores adicionales contribuirán a explicar la presencia o ausencia de rendición de cuentas en el ámbito judicial.
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