A linear programming approach to general dataflow process network verification and dimensioning

In this paper, we present linear programming-based sufficient conditions, some of them polynomial-time, to establish the liveness and memory boundedness of general dataflow process networks. Furthermore, this approach can be used to obtain safe upper bounds on the size of the channel buffers of such a network.Comment: In Proceedings ICE 2010, arXiv:1010.530

Primitives for Contract-based Synchronization

We investigate how contracts can be used to regulate the interaction between processes. To do that, we study a variant of the concurrent constraints calculus presented in [1], featuring primitives for multi-party synchronization via contracts. We proceed in two directions. First, we exploit our primitives to model some contract-based interactions. Then, we discuss how several models for concurrency can be expressed through our primitives. In particular, we encode the pi-calculus and graph rewriting.Comment: In Proceedings ICE 2010, arXiv:1010.530

O efeito de solventes orgânicos em corais fotossintéticos

Tropical coral reefs provide important ecosystem services and goods in the tropical and subtropical regions of the planet. However, the increase of anthropogenic pressures, such as marine pollution or the escalating coral biomass demand for several different economic applications, as well as the damage caused by climate change, have contributed to the degradation of this ecosystem at an alarming rate. Consequently, the international scientific community has been intensifying coral research, aiming to study and acknowledge the effects of existing stress factors and to identify possible mitigation strategies. Thus, ecotoxicology studies, targeting the effect of emergent or persistent pollutants in these organisms can contribute to the state of the art. However, there are no standardized methodologies to test tropical photosynthetic corals, and their response to organic solvents, recurrently required in toxicological appraisals, remains unknown. In this context, the present study aimed to assess the oxidative stress profiles and photochemical response of photosynthetic corals exposed to different organic solvents (ethanol, methanol and dimethyl sulfoxide – DMSO), commonly used in ecotoxicological studies, expecting to contribute to the standardization and optimization of protocols. The results from the first study, with the species Zoanthus sociatus (Hexacorallia: Zoantharia), suggested that this species is more sensitive to DMSO than to ethanol or methanol. DMSO lowest observed effect concentration (LOEC) was 0.01 mL L-1, while for ethanol and methanol LOEC were 0.1 mL L-1, even though the highest concentration of ethanol (2.9 mL L-1) was the only treatment causing mortality to Z. sociatus. Nevertheless, the distinctive response of this species evidenced the need to perform further similar studies with other coral species, given the diversity of these organisms. In this sense, a second trial was performed in order to assess the effect of the same organic solvents in two different species, Montipora digitata (Hexacorallia: Scleractinia) and Sarcophyton glaucum (Octocorallia: Alcyonaria). The species M. digitata, able to produce its own calcium carbonate skeleton, and therefore important to reef build, was more sensitive to ethanol than to methanol or DMSO. Ethanol lowest observed effect concentration (LOEC) was 0.01 mL L-1, for methanol LOEC was 0.3 mL L-1, and for DMSO LOEC was 0.1 mL L-1. Notwithstanding, the highest concentration of ethanol and DMSO (2.9 mL L-1) caused mortality in M. digitata. The species S. glaucum, unable to segregate a calcium carbonate skeleton, was more sensitive to methanol than to ethanol or DMSO. Ethanol LOEC was 2.9 mL L-1, for methanol LOEC was 0.01 mL L-1, and for DMSO LOEC was 0.3 mL L-1. Considering this, a baseline for the use of organic solvents with tropical corals was set. Nevertheless, it is important to stress out that a major knowledge gap regarding coral physiology still exists.Os recifes de coral fornecem importantíssimos bens e serviços ecossistémicos nas regiões tropicais e subtropicais do planeta. No entanto, o aumento das pressões antropogénicas, como por exemplo a poluição marinha ou a procura crescente de biomassa de coral para diversas aplicações económicas, bem como os danos provocados pelas alterações climáticas, têm contribuído para a degradação deste ecossistema a um ritmo alarmante. Consequentemente a comunidade científica internacional tem intensificado a investigação realizada com corais, com os objetivos de estudar e conhecer os efeitos dos fatores de stress existentes e identificar possíveis estratégias de mitigação. Deste modo, a realização de estudos ecotoxicológicos, com o objetivo de estudar o efeito de poluentes emergentes ou persistentes nestes organismos, pode contribuir para o avanço do estado da arte. Contudo, não existem metodologias standardizadas para testes com corais tropicais fotossintéticos e, consequentemente, a sua resposta a solventes orgânicos, frequentemente utilizados em ensaios toxicológicos, permanece desconhecida. Neste contexto, o presente estudo teve como principal objetivo analisar os perfis de stress oxidativo e a resposta fotobiológica de corais fotossintéticos expostos a diferentes solventes orgânicos (etanol, metanol e dimetil sulfoxido - DMSO), normalmente utilizados em estudos ecotoxicológicos, procurando contribuir para a standardização e otimização de protocolos. Os resultados do primeiro ensaio, realizado com a espécie Zoanthus sociatus (Ellis, 1786) (Hexacorallia: Zoantharia), sugerem que esta espécie é mais sensível ao DMSO do que ao etanol ou metanol. A concentração mais baixa com efeito (LOEC) do DMSO foi 0.01 mL L-1, enquanto que para o etanol e metanol, o LOEC foi de 0.1 mL L-1, ainda que a concentração mais alta de etanol (2.9 mL L-1) tenha sido a única a provocar mortalidade na espécie Z. sociatus. Contudo, os resultados obtidos, designadamente a forma diferenciada como esta espécie respondeu aos solventes testados, evidenciou a necessidade da realização de estudos semelhantes com outras espécies de corais, dada a diversidade apresentada por estes organismos. Neste sentido, realizou-se um segundo ensaio, para avaliar o efeito dos mesmos solventes orgânicos em duas espécies distintas, Montipora digitata (Hexacorallia: Scleractinia) e Sarcophyton glaucum (Octocorallia: Alcyonaria). A espécie M. digitata, com capacidade de segregar o seu exosqueleto de carbonato de cálcio, cujo papel na formação de recifes é imprescindível, foi mais sensível ao etanol do que ao metanol ou DMSO. O LOEC para o etanol foi de 0.01 mL L-1, para o metanol foi de 0.3 mL L-1 e para o DMSO foi de 0.1 mL L-1. Ainda assim, a concentração mais alta de etanol e DMSO (2.9 mL L-1) causou mortalidade na espécie M. digitata. A espécie S. glaucum, sem capacidade de segregar exosqueleto, foi mais sensível ao metanol do que ao etanol ou DMSO. O LOEC para a exposição a etanol foi de 2.9 mL L-1, para a exposição a metanol 0.01 mL L-1 e para a exposição a DMSO 0.3 mL L-1. Considerando os resultados obtidos, os solventes orgânicos podem ser utilizados em ecotoxicologia de corais tropicais com uma base sólida. Não obstante, é importante referir que existe ainda uma grande falta de informação no que diz respeito à fisiologia de corais, que deve ser aprofundada.Mestrado em Biologia Marinha Aplicad

Effective thermal dynamics following a quantum quench in a spin chain

We study the nonequilibrium dynamics of the Quantum Ising Model following an abrupt quench of the transverse field. We focus on the on-site autocorrelation function of the order parameter, and extract the phase coherence time $\tau^{\phi}_Q$ from its asymptotic behavior. We show that the initial state determines $\tau^{\phi}_Q$ only through an effective temperature set by its energy and the final Hamiltonian. Moreover, we observe that the dependence of $\tau^{\phi}_Q$ on the effective temperature fairly agrees with that obtained in thermal equilibrium as a function of the equilibrium temperature.Comment: 4 pages, 4 figures. Published versio

Single-shot implementation of dispersion-scan for the characterization of ultrashort laser pulses

We demonstrate a novel, single-shot ultrafast diagnostic, based on the dispersion-scan (d-scan) technique. In this implementation, rather than scanning wedges to vary the dispersion as in standard d-scan, the pulse to be measured experiences a spatially varying amount of dispersion in a Littrow prism. The resulting beam is then imaged into a second-harmonic generation crystal and an imaging spectrometer is used to measure the two-dimensional trace, which is analyzed using the d-scan retrieval algorithm. We compare the single-shot implementation with the standard d-scan for the measurement of sub-3.5-fs pulses from a hollow core fiber pulse compressor. We show that the retrieval algorithm used to extract amplitude and phase of the pulse provides comparable results, proving the validity of the new single-shot implementation down to near single-cycle durations.Comment: 6 pages, 4 figure

International promotion of japanese new no-agestatement Whiskies: exploring swiss consumers’ perception

Japanese Whisky has seen a tremendous jump in popularity in the recent years. Collecting numerous rewards in the first years of the new century, made the spirit coming from the country of the rising sun extremely sought after. So much so that the distilleries in Japan could not keep up with the fast-growing demand coming from outside of the land. Being between a rock and a hard place, they had to make a decision quickly, so they decided to get to the root of the problem, aged Whiskies. Indeed, until now, Japan was known for its excellent aged spirits. However, companies decided to do the unthinkable, since they were not able to produce enough aged bottles they decided to discontinue some and launch the new no-age-statement Whiskies, NAS for short. The objective of this thesis is to demonstrate that “age is just a number” and that good quality Whisky can be found in these new NAS bottles and, that they actually can surpass the competition coming from the aged ones. We will focus on the Swiss market since we have access more easily to primary data coming from both the demand and the supply side. The discontinuation of the popular aged Whiskies, such as the Hibiki brand, was and still is considered a bold move, especially in a market where “age equals quality”, it was seen crucial to have aged bottles coming from these distilleries, but the results of this paper show the opposite. We can see that the imports of Japanese Whiskies have been increasing tremendously compared to the competition. Furthermore, NAS bottles did better than the aged ones in the different tests we made. According to the surveys conducted with suppliers and distributors of Whisky in Switzerland and the International Trade Centre tools. The demand for Japanese spirit keeps rising even after the decision of stopping the productions of its flagship’s bottles. The future of the Japanese spirit in Switzerland is bright. Thanks to the very unique or luxurious bottle design, people tend to forget the age and simply choose the most appealing bottle of the lot. Therefore, NAS bottles were able to obtain such good results in the tests and, of course, thanks the quality of the spirit itself. People were not able to tell the difference between the aged bottles and the no-age-statement ones

Tensor-multi-scalar theories: relativistic stars and 3+1 decomposition

Gravitational theories with multiple scalar fields coupled to the metric and each other --- a natural extension of the well studied single-scalar-tensor theories --- are interesting phenomenological frameworks to describe deviations from general relativity in the strong-field regime. In these theories, the $N$-tuple of scalar fields takes values in a coordinate patch of an $N$-dimensional Riemannian target-space manifold whose properties are poorly constrained by weak-field observations. Here we introduce for simplicity a non-trivial model with two scalar fields and a maximally symmetric target-space manifold. Within this model we present a preliminary investigation of spontaneous scalarization for relativistic, perfect fluid stellar models in spherical symmetry. We find that the scalarization threshold is determined by the eigenvalues of a symmetric scalar-matter coupling matrix, and that the properties of strongly scalarized stellar configurations additionally depend on the target-space curvature radius. In preparation for numerical relativity simulations, we also write down the $3+1$ decomposition of the field equations for generic tensor-multi-scalar theories.Comment: 32 pages, 8 figures, 1 table, invited contribution to the Classical and Quantum Gravity Focus Issue "Black holes and fundamental fields". v3: version in press in CQG, with various improvements in response to the referees' comments. In particular, the 3+1 decomposition now allows for matte

Effect of the operating conditions on the anaerobic digestion of wheatgrass for chemicals and energy production

Open Access via the Springer Compact Agreement Acknowledgments The authors wish to acknowledge Carnegie Trust for the Universities of Scotland (Research Incentive Grant 70307), CAPES (Coordination for the Improvement of Higher Education Personnel) for the financial support (Process 011944/2013-07), Mrs Elizabeth Hendrie and Ms Gabriela Paupitz for the technical collaboration and Mr Andrew Rennie (Gask Farm, Turriff, Aberdeenshire, UK) for kindly providing the inoculum used in the experiments.Peer reviewedPostprintPublisher PD

Long time dynamics following a quench in an integrable quantum spin chain: local versus non-local operators and effective thermal behavior

We study the dynamics of the quantum Ising chain following a zero-temperature quench of the transverse field strength. Focusing on the behavior of two-point spin correlation functions, we show that the correlators of the order parameter display an effective asymptotic thermal behavior, i.e., they decay exponentially to zero, with a phase coherence rate and a correlation length dictated by the equilibrium law with an effective temperature set by the energy of the initial state. On the contrary, the two-point correlation functions of the transverse magnetization or the density-of-kinks operator decay as a power-law and do not exhibit thermal behavior. We argue that the different behavior is linked to the locality of the corresponding operator with respect to the quasi-particles of the model: non-local operators, such as the order parameter, behave thermally, while local ones do not. We study which features of the two-point correlators are a consequence of the integrability of the model by analizing their robustness with respect to a sufficiently strong integrability-breaking term.Comment: 18 pages, 11 figures, published version. Extensive changes, one author adde

A predictive and user-centric approach to Machine Learning in data streaming scenarios

info:eu-repo/semantics/acceptedVersio