Coincidence analysis in ANTARES: Potassium-40 and muons

A new calibration technique using natural background light of sea water has been recently developed for the ANTARES experiment. The method relies on correlated coincidences produced in triplets of optical modules by Cherenkov light of beta-particles originated from Potassium-40 decays. A simple but powerful approach to atmospheric muon flux studies is currently being developed based on similar ideas of coincidence analysis. This article presents the two methods in certain detail and explains their role in the ANTARES experiment.Comment: 4 pages, 3 figures, published in the proceedings of Rencontres de Moriond EW 200

Causal Consistency for Reversible Multiparty Protocols

In programming models with a reversible semantics, computational steps can be undone. This paper addresses the integration of reversible semantics into process languages for communication-centric systems equipped with behavioral types. In prior work, we introduced a monitors-as-memories approach to seamlessly integrate reversible semantics into a process model in which concurrency is governed by session types (a class of behavioral types), covering binary (two-party) protocols with synchronous communication. The applicability and expressiveness of the binary setting, however, is limited. Here we extend our approach, and use it to define reversible semantics for an expressive process model that accounts for multiparty (n-party) protocols, asynchronous communication, decoupled rollbacks, and abstraction passing. As main result, we prove that our reversible semantics for multiparty protocols is causally-consistent. A key technical ingredient in our developments is an alternative reversible semantics with atomic rollbacks, which is conceptually simple and is shown to characterize decoupled rollbacks.Comment: Extended, revised version of a PPDP'17 paper (https://doi.org/10.1145/3131851.3131864

Partial resampling to approximate covering integer programs

We consider column-sparse covering integer programs, a generalization of set cover, which have a long line of research of (randomized) approximation algorithms. We develop a new rounding scheme based on the Partial Resampling variant of the Lov\'{a}sz Local Lemma developed by Harris & Srinivasan (2019). This achieves an approximation ratio of $1 + \frac{\ln (\Delta_1+1)}{a_{\min}} + O\Big( \log(1 + \sqrt{ \frac{\log (\Delta_1+1)}{a_{\min}}} \Big)$, where $a_{\min}$ is the minimum covering constraint and $\Delta_1$ is the maximum $\ell_1$-norm of any column of the covering matrix (whose entries are scaled to lie in $[0,1]$). When there are additional constraints on the variable sizes, we show an approximation ratio of $\ln \Delta_0 + O(\log \log \Delta_0)$ (where $\Delta_0$ is the maximum number of non-zero entries in any column of the covering matrix). These results improve asymptotically, in several different ways, over results of Srinivasan (2006) and Kolliopoulos & Young (2005). We show nearly-matching inapproximability and integrality-gap lower bounds. We also show that the rounding process leads to negative correlation among the variables, which allows us to handle multi-criteria programs

Dimensionally continued Oppenheimer-Snyder gravitational collapse II: solutions in odd dimensions

The Lovelock gravity extends the theory of general relativity to higher dimensions in such a way that the field equations remain of second order. The theory has many constant coefficients with no a priori meaning. Nevertheless it is possible to reduce them to two, the cosmological constant and Newton's constant. In this process one separates theories in even dimensions from theories in odd dimensions. In a previous work gravitational collapse in even dimensions was analysed. In this work attention is given to odd dimensions. It is found that black holes also emerge as the final state of gravitational collapse of a regular dust fluid.Comment: 16 pages, 3figures, latex Journal: to appear in Journal of Mathematical Physic

The pattern and the fabric : complexity and ambiguity in the solo flute works of Toshio Hosokawa

Dissertação de mestrado em Evolução e Biologias Humanas, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.Os processos tafonómicos têm um papel muito importante tanto no processo de decomposição como na estimativa do intervalo pós-morte (PMI). O presente estudo teve dois objectivos: observar as alterações tafonómicas no processo de decomposição em diferentes ambientes e estimar o intervalo pós morte segundo o cálculo dos graus-dia acumulados (ADD) de Megyesi e colaboradores (2005), com o auxílio do registo das temperaturas realizado pelo datalogger IBT Temp Logger (Embedded Data Systems). Sete ambientes (solo humoso; solo calcário; areia da praia; solo arenoso; solo argiloso; água doce e água salgada) foram recolhidos no distrito de Coimbra, Portugal, em Abril de 2014 sendo depois depositados em contentores onde permaneceram por 8 semanas. Cada ambiente foi replicado de forma a proporcionar um registo da evolução da decomposição por volta das 4 semanas. A amostra consistiu em costeletas de porco (Sus scrofa domesticus) provenientes de um matadouro da região. Foram observados vários estados de decomposição, categorizados segundo Galloway (1997) e Behrensmeyer (1978). Através da atribuição de pontuação a cada categoria para o cálculo dos ADD, estimou-se o PMI, tendo-se obtido um valor próximo ao real com uma diferença máxima de 5 dias. Observou-se que os meios aquáticos decompuseram o modelo animal mais rapidamente e em estados de decomposição mais extremos que os que se encontravam nos diferentes solos sendo que, mesmo entre estes o processo teve uma grande variabilidade.Taphonomic processes play an important role both in the decomposition process as in estimating the postmortem interval (PMI). Our purpose was: first, observe the taphonomic changes in the decomposition process in different environments, and second, estimate the PMI by accumulated degree-days (ADD) (Megyesi et al., 2005) using the temperature recording datalogger IBT Temp Logger (Embedded Data Systems). Seven environments (humous soil; calcareous soil; beach sand; sandy soil; clay soil; freshwater and saltwater) were recovered from the district of Coimbra, Portugal, through April 2014 and placed into individual 6L plastic storage boxes during 8 weeks. Each environment was replicated in order to make an observation 4 weeks after the beginning of the experiment. Our sample was pork chops (Sus scrofa domesticus) from a slaughterhouse in the very same region. Results revealed various states of decomposition, categorized according Galloway (1997) and Behrensmeyer (1978). Estimating the PMI using ADD proved to be relatively accurate with a maximum variation of 5 days to the animal’s real time of death. We conclude that bodies under water have a higher decomposition rate, both in time and stages. In addiction, we observed a great variability in the decomposition process according to the surrounding environment