A Comparison of Two-Level and Multi-level Modelling for Cloud-Based Applications

The final publication is available at Springer via http://dx.doi.org/10.1007/978-3-319-21151-0_2The Cloud Modelling Framework (CloudMF) is an approach to apply model-driven engineering principles to the specification and execution of cloud-based applications. It comprises a domain-specific language to model the deployment topology of multi-cloud applications, along with a models@run-time environment to facilitate reasoning and adaptation of these applications at run-time. This paper reports on some challenges encountered during the design of CloudMF, related to the adoption of the two-level modelling approach and especially the type-instance pattern. Moreover, it proposes the adoption of an alternative, multi-level modelling approach to tackle these challenges, and provides a set of criteria to compare both approaches.The research leading to these results has received funding from the European Commission’s Seventh Framework Programme (FP7/2007-2013) under grant agreement numbers 317715 (PaaSage), 318392 (Broker@Cloud), and 611125 (MONDO), the Spanish Ministry under project Go Lite (TIN2011-24139), and the Madrid Region under project SICOMORO (S2013/ICE-3006)

Quadratic Effective Action for QED in D=2,3 Dimensions

We calculate the effective action for Quantum Electrodynamics (QED) in D=2,3 dimensions at the quadratic approximation in the gauge fields. We analyse the analytic structure of the corresponding nonlocal boson propagators nonperturbatively in k/m. In two dimensions for any nonzero fermion mass, we end up with one massless pole for the gauge boson . We also calculate in D=2 the effective potential between two static charges separated by a distance L and find it to be a linearly increasing function of L in agreement with the bosonized theory (massive Sine-Gordon model). In three dimensions we find nonperturbatively in k/m one massive pole in the effective bosonic action leading to screening. Fitting the numerical results we derive a simple expression for the functional dependence of the boson mass upon the dimensionless parameter e^{2}/m .Comment: 10 pages, 2 figure

Engineering fidelity echoes in Bose-Hubbard Hamiltonians

We analyze the fidelity decay for a system of interacting bosons described by a Bose-Hubbard Hamiltonian. We find echoes associated with "non-universal" structures that dominate the energy landscape of the perturbation operator. Despite their classical origin, these echoes persist deep into the quantum (perturbative) regime and can be described by an improved random matrix modeling. In the opposite limit of strong perturbations (and high enough energies), classical considerations reveal the importance of self-trapping phenomena in the echo efficiency.Comment: 6 pages, use epl2.cls class, 5 figures Cross reference with nlin, quant-phy

Effective Action for QED with Fermion Self-Interaction in D=2 and D=3 Dimensions

In this work we discuss the effect of the quartic fermion self-interaction of Thirring type in QED in D=2 and D=3 dimensions. This is done through the computation of the effective action up to quadratic terms in the photon field. We analyze the corresponding nonlocal photon propagators nonperturbatively in % \frac{k}{m}, where k is the photon momentum and m the fermion mass. The poles of the propagators were determined numerically by using the Mathematica software. In D=2 there is always a massless pole whereas for strong enough Thirring coupling a massive pole may appear . For D=3 there are three regions in parameters space. We may have one or two massive poles or even no pole at all. The inter-quark static potential is computed analytically in D=2. We notice that the Thirring interaction contributes with a screening term to the confining linear potential of massive QED_{2}. In D=3 the static potential must be calculated numerically. The screening nature of the massive QED$_{3}$ prevails at any distance, indicating that this is a universal feature of % D=3 electromagnetic interaction. Our results become exact for an infinite number of fermion flavors.Comment: Latex, 13 pages, 3 figure

Decoherence by engineered quantum baths

We introduce, and determine decoherence for, a wide class of non-trivial quantum spin baths which embrace Ising, XY and Heisenberg universality classes coupled to a two-level system. For the XY and Ising universality classes we provide an exact expression for the decay of the loss of coherence beyond the case of a central spin coupled uniformly to all the spins of the baths which has been discussed so far in the literature. In the case of the Heisenberg spin bath we study the decoherence by means of the time-dependent density matrix renormalization group. We show how these baths can be engineered, by using atoms in optical lattices.Comment: 4 pages, 4 figure

Identificação de microssatélites e síntese de primes para erva-mate a partir de programas de bioinformática.

A erva-mate (Ilex paraguariensis S. T. Hill) gera o produto florestal não madeireiro mais importante do agronegócio da região Sul do Brasil. A demanda internacional pela erva-mate vem aumentando, favorecendo o desenvolvimento da sua produção e competitividade. A caracterização genética é indispensável para o estabelecimento de estratégias de conservação e melhoramento genéticos para essa espécie. Atualmente, diferentes ferramentas genômicas estão disponíveis para desenvolvimento de marcadores moleculares, sendo os microssatélites, ou SSRs (sequências simples repetidas) uma das mais utilizadas no estudo genético de populações. Assim, o objetivo desde trabalho foi identificar e desenvolver microssatélites para erva-mate. O DNA de um indivíduo foi utilizado para realizar, a partir da plataforma Illumina-Miseq, um total de 12.933.970 leituras. Para a sua identificação, foram utilizados diferentes programas: PERF, SSR_pipeline e Primer3Plus. Com o auxílio do PERF, foram analisadas as sequências (em arquivo fasta), totalizando 17.715 ocorrências repetidas para variados números de motifs repetidos. O SSR_pipeline utilizou outros arquivos de entrada (fastq) com 12.933.970 leituras e identificou inúmeros SSRs. Assim, associando os resultados dos dois programas, pares de primers flanqueando os microssatélites foram desenhados no Primer3Plus para 18 marcadores. Alguns parâmetros especificados foram: tamanhos, temperaturas e porcentagem de GC (mínimos, ideais e máximos). Seis potenciais marcadores identificados serão validados para a confecção dos iniciadores para esta espécie. Essa ferramenta deverá ser aplicada para análises genéticas diversas, na caracterização genética de populações naturais e sintéticas e em bancos de germoplasma. Novos recursos de bioinformática poderão ser explorados para essa mesma finalidade.Resumo

Muscles in “Concert”: Study of Primary Motor Cortex Upper Limb Functional Topography

BACKGROUND: Previous studies with Transcranial Magnetic Stimulation (TMS) have focused on the cortical representation of limited group of muscles. No attempts have been carried out so far to get simultaneous recordings from hand, forearm and arm with TMS in order to disentangle a 'functional' map providing information on the rules orchestrating muscle coupling and overlap. The aim of the present study is to disentangle functional associations between 12 upper limb muscles using two measures: cortical overlapping and cortical covariation of each pair of muscles. Interhemispheric differences and the influence of posture were evaluated as well. METHODOLOGY/PRINCIPAL FINDINGS: TMS mapping studies of 12 muscles belonging to hand, forearm and arm were performed. Findings demonstrate significant differences between the 66 pairs of muscles in terms of cortical overlapping: extremely high for hand-forearm muscles and very low for arm vs hand/forearm muscles. When right and left hemispheres were compared, overlapping between all possible pairs of muscles in the left hemisphere (62.5%) was significantly higher than in the right one (53.5% ). The arm/hand posture influenced both measures of cortical association, the effect of Position being significant [p = .021] on overlapping, resulting in 59.5% with prone vs 53.2% with supine hand, but only for pairs of muscles belonging to hand and forearm, while no changes occurred in the overlapping of proximal muscles with those of more distal districts. CONCLUSIONS/SIGNIFICANCE: Larger overlapping in the left hemisphere could be related to its lifetime higher training of all twelve muscles studied with respect to the right hemisphere, resulting in larger intra-cortical connectivity within primary motor cortex. Altogether, findings with prone hand might be ascribed to mechanisms facilitating coupling of muscles for object grasping and lifting -with more proximal involvement for joint stabilization- compared to supine hand facilitating actions like catching. TMS multiple-muscle mapping studies permit a better understanding of motor control and 'plastic' reorganization of motor system

Adsorbate-Induced Segregation of Cobalt from PtCo Nanoparticles: Modeling Au Doping and Core AuCo Alloying for the Improvement of Fuel Cell Cathode Catalysts

Platinum, when used as a cathode material for the oxygen reduction reaction, suffers from high overpotential and possible dissolution, in addition to the scarcity of the metal and resulting cost. Although the introduction of cobalt has been reported to improve reaction kinetics and decrease the precious metal loading, surface segregation or complete leakage of Co atoms causes degradation of the membrane electrode assembly, and either of these scenarios of structural rearrangement eventually decreases catalytic power. Ternary PtCo alloys with noble metals could possibly maintain activity with a higher dissolution potential. First-principles-based theoretical methods are utilized to identify the critical factors affecting segregation in Pt–Co binary and Pt–Co–Au ternary nanoparticles in the presence of oxidizing species. With a decreasing share of Pt, surface segregation of Co atoms was already found to become thermodynamically viable in the PtCo systems at low oxygen concentrations, which is assigned to high charge transfer between species. While the introduction of gold as a dopant caused structural changes that favor segregation of Co, creation of CoAu alloy core is calculated to significantly suppress Co leakage through modification of the electronic properties. The theoretical framework of geometrically different ternary systems provides a new route for the rational design of oxygen reduction catalysts

Adiabatic perturbation theory: from Landau-Zener problem to quenching through a quantum critical point

We discuss the application of the adiabatic perturbation theory to analyze the dynamics in various systems in the limit of slow parametric changes of the Hamiltonian. We first consider a two-level system and give an elementary derivation of the asymptotics of the transition probability when the tuning parameter slowly changes in the finite range. Then we apply this perturbation theory to many-particle systems with low energy spectrum characterized by quasiparticle excitations. Within this approach we derive the scaling of various quantities such as the density of generated defects, entropy and energy. We discuss the applications of this approach to a specific situation where the system crosses a quantum critical point. We also show the connection between adiabatic and sudden quenches near a quantum phase transitions and discuss the effects of quasiparticle statistics on slow and sudden quenches at finite temperatures.Comment: 20 pages, 3 figures, contribution to "Quantum Quenching, Annealing and Computation", Eds. A. Das, A. Chandra and B. K. Chakrabarti, Lect. Notes in Phys., Springer, Heidelberg (2009, to be published), reference correcte

Clinical and molecular determinants of extrahepatic disease progression (ePD) in initially unresectable, liver-limited metastatic colorectal cancer (mCRC)

e15511Background: In the last years, availability of active upfront systemic regimens, development of surgical techniques and diffusion of locoregional treatments (LrTx) increased the therapeutic o..