A corrida global por terras desde 2008 : a América do Sul na expansão global do "land grab"

Dissertação de Mestrado em Relações InternacionaisResumo Desde 2008, a procura internacional por terras agrícolas destacou o “land grab” como um novo fenómeno no contexto das relações internacionais como resultado da conjugação das crises alimentar, energética e financeira. Em particular, na América Sul o “land grab” revela-se especialmente pertinente para a compreensão das dinâmicas económicas, sociais e políticas na sub-região pela complexidade com que este se manifesta, pelos agentes e motivações envolvidos e pelo debate associado à sua expansão. Esta discussão em torno dos impactos do “land grab” é visível ao nível da oposição entre os conceitos de “land sovereignty” e “land governance”. Partindo da análise deste confronto, esta dissertação pretende compreender quais os impactos que o “land grab” tem ao nível da inserção internacional dos países sul-americanos. Em particular, pretende-se compreender se a expansão do “land grab” na América do Sul se constitui como uma elemento de autonomia ou dependência ao nível da inserção internacional dos países sul-americanos.ABSTRACT Since 2008, the international demand for agricultural land highlighted land grabs as a new phenomenon in the context of international relations as a result of the combination of food, energy and financial crises. In particular, in South America land grabs prove to be particularly relevant for the understanding of economic, social and political dynamics in the sub-region by the complexity with which it manifests, by the actors and motivations involved and the debate associated with its expansion. The discussion on the impacts of land grabs is visible at the level of the opposition between the concepts of "sovereignty land" and "land governance". Based on the analysis of this confrontation, this dissertation aims to understand the impacts of land grabs at the level of international integration of South American countries. In particular, it aims to understand if the expansion of land grabs in South America constitutes as an element of autonomy or dependence at the level of international integration of South American countries

ZONAS INUNDÁVEIS E QUANTIFICAÇÃO DO RISCO DE INUNDAÇÃO EM MEIOS URBANOS: ESTUDO EM COIMBRA

As inundações urbanas são, hoje em dia, um tema bastante atual em praticamente todos os países e, em particular, em zonas muito urbanizadas. Os danos por elas causados são, frequentemente, bastante graves, o que se afigura serem necessárias medidas preventivas para evitar, quando possível, ou mitigar esses eventos. A crescente urbanização e, eventualmente, as alterações climáticas recentes apresentam um forte contributo para os eventos de inundações em zonas urbanas. Associados às preocupações inerentes às inundações, surgem os mapas de risco, os quais classificam determinada zona, quando atingida por uma inundação, consoante as consequências sofridas. Em 2007, a União Europeia publicou a Diretiva 2007/60/CE que prevê, para todos os Estados-Membros, o dever de elaborarem mapas de risco de inundação. Assim, este artigo tem como objetivo a elaboração de mapas de zonas inundáveis e mapas de risco de inundação para a Zona Central de Coimbra, Portugal. Com esse propósito, simularam-se eventos pluviométricos com diferentes períodos de retorno e, com base nos resultados, elaboraram-se os referidos mapas. Através da sua elaboração, verificou-se que estes proporcionavam uma indicação clara de quais as zonas e os edifícios mais sujeitos a sofrerem maiores prejuízos em caso de inundação

Search for Physics beyond the Standard Model in Events with Overlapping Photons and Jets

Results are reported from a search for new particles that decay into a photon and two gluons, in events with jets. Novel jet substructure techniques are developed that allow photons to be identified in an environment densely populated with hadrons. The analyzed proton-proton collision data were collected by the CMS experiment at the LHC, in 2016 at root s = 13 TeV, and correspond to an integrated luminosity of 35.9 fb(-1). The spectra of total transverse hadronic energy of candidate events are examined for deviations from the standard model predictions. No statistically significant excess is observed over the expected background. The first cross section limits on new physics processes resulting in such events are set. The results are interpreted as upper limits on the rate of gluino pair production, utilizing a simplified stealth supersymmetry model. The excluded gluino masses extend up to 1.7 TeV, for a neutralino mass of 200 GeV and exceed previous mass constraints set by analyses targeting events with isolated photons.Peer reviewe

Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at √s = 13 TeV

Abstract The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric (d̂ t) and chromomagnetic (μ̂ t) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb−1. The linearized variable AFB(1) is used to approximate the asymmetry. Candidate t t ¯ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for t t ¯ final states. The values found for the parameters are AFB(1)=0.048−0.087+0.095(stat)−0.029+0.020(syst),μ̂t=−0.024−0.009+0.013(stat)−0.011+0.016(syst), and a limit is placed on the magnitude of | d̂ t| < 0.03 at 95% confidence level. [Figure not available: see fulltext.

Measurement of t(t)over-bar normalised multi-differential cross sections in pp collisions at root s=13 TeV, and simultaneous determination of the strong coupling strength, top quark pole mass, and parton distribution functions

Peer reviewe

An embedding technique to determine ττ backgrounds in proton-proton collision data

An embedding technique is presented to estimate standard model tau tau backgrounds from data with minimal simulation input. In the data, the muons are removed from reconstructed mu mu events and replaced with simulated tau leptons with the same kinematic properties. In this way, a set of hybrid events is obtained that does not rely on simulation except for the decay of the tau leptons. The challenges in describing the underlying event or the production of associated jets in the simulation are avoided. The technique described in this paper was developed for CMS. Its validation and the inherent uncertainties are also discussed. The demonstration of the performance of the technique is based on a sample of proton-proton collisions collected by CMS in 2017 at root s = 13 TeV corresponding to an integrated luminosity of 41.5 fb(-1).Peer reviewe

Measurement of the Splitting Function in &ITpp &ITand Pb-Pb Collisions at root&ITsNN&IT=5.02 TeV

Data from heavy ion collisions suggest that the evolution of a parton shower is modified by interactions with the color charges in the dense partonic medium created in these collisions, but it is not known where in the shower evolution the modifications occur. The momentum ratio of the two leading partons, resolved as subjets, provides information about the parton shower evolution. This substructure observable, known as the splitting function, reflects the process of a parton splitting into two other partons and has been measured for jets with transverse momentum between 140 and 500 GeV, in pp and PbPb collisions at a center-of-mass energy of 5.02 TeV per nucleon pair. In central PbPb collisions, the splitting function indicates a more unbalanced momentum ratio, compared to peripheral PbPb and pp collisions.. The measurements are compared to various predictions from event generators and analytical calculations.Peer reviewe

Calibration of the CMS hadron calorimeters using proton-proton collision data at root s=13 TeV

Methods are presented for calibrating the hadron calorimeter system of theCMSetector at the LHC. The hadron calorimeters of the CMS experiment are sampling calorimeters of brass and scintillator, and are in the form of one central detector and two endcaps. These calorimeters cover pseudorapidities vertical bar eta vertical bar ee data. The energy scale of the outer calorimeters has been determined with test beam data and is confirmed through data with high transverse momentum jets. In this paper, we present the details of the calibration methods and accuracy.Peer reviewe

Measurement of the Jet Mass Distribution and Top Quark Mass in Hadronic Decays of Boosted Top Quarks in pp Collisions at root s=13 TeV

A measurement is reported of the jet mass distribution in hadronic decays of boosted top quarks produced in pp collisions at root s = 13 TeV. The data were collected with the CMS detector at the LHC and correspond to an integrated luminosity of 35.9 fb(-1). The measurement is performed in the lepton + jets channel of t (t) over bar events, where the lepton is an electron or muon. The products of the hadronic top quark decay t -> bW -> bq (q) over bar' are reconstructed as a single jet with transverse momentum larger than 400 GeV. The t (t) over bar cross section as a function of the jet mass is unfolded at the particle level and used to extract a value of the top quark mass of 172.6 +/- 2.5 GeV. A novel jet reconstruction technique is used for the first time at the LHC, which improves the precision by a factor of 3 relative to an earlier measurement. This highlights the potential of measurements using boosted top quarks, where the new technique will enable future precision measurements.Peer reviewe

Search for top squark pair production in a final state with two tau leptons in proton-proton collisions at root s=13 TeV

A search for pair production of the supersymmetric partner of the top quark, the top squark, in proton-proton collision events at s = 13 TeV is presented in a final state containing hadronically decaying tau leptons and large missing transverse momentum. This final state is highly sensitive to high-tan beta or higgsino-like scenarios in which decays of electroweak gauginos to tau leptons are dominant. The search uses a data set corresponding to an integrated luminosity of 77.2 fb(-1), which was recorded with the CMS detector during 2016 and 2017. No significant excess is observed with respect to the background prediction. Exclusion limits at 95% confidence level are presented in the top squark and lightest neutralino mass plane within the framework of simplified models, in which top squark masses up to 1100 GeV are excluded for a nearly massless neutralino.Peer reviewe