University of Lisbon

About: University of Lisbon is a education organization based out in Lisbon, Lisboa, Portugal. It is known for research contribution in the topics: Population & European union. The organization has 19122 authors who have published 48503 publications receiving 1102623 citations. The organization is also known as: Universidade de Lisboa & Lisbon University.

Search for electroweak production of supersymmetric particles in final states with two or three leptons at √s=13 TeV with the ATLAS detector

Abstract: A search for the electroweak production of charginos, neutralinos and sleptons decaying into final states involving two or three electrons or muons is presented. The analysis is based on 36.1 fb$^{-1}$ of $\sqrt{s}=13$ TeV proton–proton collisions recorded by the ATLAS detector at the Large Hadron Collider. Several scenarios based on simplified models are considered. These include the associated production of the next-to-lightest neutralino and the lightest chargino, followed by their decays into final states with leptons and the lightest neutralino via either sleptons or Standard Model gauge bosons, direct production of chargino pairs, which in turn decay into leptons and the lightest neutralino via intermediate sleptons, and slepton pair production, where each slepton decays directly into the lightest neutralino and a lepton. No significant deviations from the Standard Model expectation are observed and stringent limits at 95% confidence level are placed on the masses of relevant supersymmetric particles in each of these scenarios. For a massless lightest neutralino, masses up to 580 GeV are excluded for the associated production of the next-to-lightest neutralino and the lightest chargino, assuming gauge-boson mediated decays, whereas for slepton-pair production masses up to 500 GeV are excluded assuming three generations of mass-degenerate sleptons.

Deep structure of the West African continental margin (Congo, Zaïre, Angola), between 5°S and 8°S, from reflection/refraction seismics and gravity data

Abstract: SUMMARY The deep structure of the West African continental margin between 5°S and 8°S was investigated using vertical reflection and wide-angle reflection/refraction techniques, during the ZaiAngo project, a joint programme conducted in 2000 April by Ifremer and TotalFinaElf. To penetrate below the salt layer, a non-conventional, low-frequency seismic source was used in the ‘single-bubble’ mode, together with ocean bottom instruments (hydrophones and seismometers) and a 4.5 km long streamer that recorded multichannel seismic reflection (MCS). The data show that the continental crust thins abruptly over a lateral distance of less than 50 km, from 30 km thick below the continental platform (based on gravity data), to less than 4 km thick below the Lower Congo Basin that formed prior to the Aptian salt deposition. This subsalt sedimentary basin (180 km wide, 4 km thick, with velocities varying from 4.7 km s−1 to 5.8 km s−1 at the bottom) is located between the foot of the continental slope and the oceanic domain. It is underlain by crust of an intermediary or transitional type, between continental crust and what can be recognized as oceanic crust. In the transitional zone, a crustal upper layer is present below the pre-salt sedimentary basin, 3 to 7 km thick, with velocities increasing from 5.8 km s−1 at the top to 6.8 km s−1 at the bottom of the layer. This layer appears to thin regularly, from 6–7 km thick below the depocentre of the pre-salt sedimentary basin to 3–4 km thick below the western termination of the basin. Below this upper crustal layer, an anomalous velocity layer (7.2 to 7.8 km s−1), is documented, below the eastern side of the basin, where the crustal thinning is at a maximum. The origin of this layer is unknown. Several arguments, like rifting duration (between 15 Ma and 30 Ma) or the absence of seaward-dipping reflectors, precludes the hypothesis of underplated mantle material, but other hypotheses (such as serpentinized material or high-grade metamorphic crustal rocks or a mixture of mafic and ultramafic crustal rocks) are plausible. Near the ocean termination of the basin, the transitional zone is bounded to the west by a basement ridge that is clearly documented on two profiles (‘7+11’ and 14) having a dense ocean bottom seismometer/hydrophone (OBS/OBH) spacing. On these profiles, an anomalous velocity layer is present in the westernmost part of the transitional zone (below the basement ridge) and in the oceanic domain. This layer, absent on profile 3, may be related either to oceanization and slow seafloor spreading processes or to a consequence of the rifting process.

On the mathematical foundations of MACBETH

Abstract: MACBETH (Measuring Attractiveness by a Categorical Based Evaluation Technique) is a multicriteria decision analysis approach that requires only qualitative judgements about differences of value to help an individual or a group quantify the relative attractiveness of options. We present an up-to-date survey of the mathematical foundations of MACBETH. Reference is also made to real-world applications and an extensive bibliography, spanning back to the early 1990’s, is provided.

Mental Mechanisms: Philosophical Perspectives on Cognitive Neuroscience

Abstract: In this book, William Bechtel outlines a new and original program for the philosophy of cognitive science using an original concept of mechanism as its core idea. Bechtel’s concept of mechanism is intended to allow for a naturalized science of the mind that is continuous with the other sciences. Bechtel is a philosopher of science that is interested in how science is actually made and therefore the book is full of examples taken from several researches made in cognitive science. In this book review, I will focus on the philosophical parts of the book and a few illustrative examples. The book is divided into seven chapters. In chapter 1, Bechtel introduces his notion of mechanism. In chapter 2 and 3, Bechtel looks at two mental mechanistic explanations in cognitive science: memory and vision. In chapter 4, Bechtel suggests how a mechanistic explanation of the mental avoids some of the pitfalls of the mind-brain problem. In chapter 5 and 6, Bechtel proposes a mechanistic account of the mental that explains mental representation. In the final chapter, chapter 7, Bechtel argues that this mechanistic view of the mental does not dehumanize people, but instead that our humanity derives from us being a very specific kind of mechanism that is different from all others. There are two main ideas in the book that are intimately related and that have several philosophical consequences. One is Bechtel’s view of what a mechanism is, another is his defence of the scientific practice of reconstructing the phenomenon. In fact, Bechtel’s book is itself an essay on reconstructing the concept of mechanism. I will start with the concept of reconstructing the phenomenon and then introduce Bechtel’s concept of mechanism. Bechtel says that in scientific research we do not always have a clear view of what is the phenomenon about to be studied when we start. Scientists start studying certain mechanisms and might change their mind about what they do throughout their research. Bechtel says: