Searches for heavy Higgs bosons in two-Higgs-doublet models and for t→ch decay using multilepton and diphoton final states in pp collisions at 8 TeV

Searches are presented for heavy scalar (H) and pseudoscalar (A) Higgs bosons posited in the two doublet model (2HDM) extensions of the standard model (SM). These searches are based on a data sample of pp collisions collected with the CMS experiment at the LHC at a center-of-mass energy of root s = 8 TeV and corresponding to an integrated luminosity of 19.5 fb(-1). The decays H -> hh and A -> Zh, where h denotes an SM-like Higgs boson, lead to events with three or more isolated charged leptons or with a photon pair accompanied by one or more isolated leptons. The search results are presented in terms of the H and A production cross sections times branching fractions and are further interpreted in terms of 2HDM parameters. We place 95% C.L. cross section upper limits of approximately 7 pb on sigma B for H -> hh and 2 pb for A -> Zh. Also presented are the results of a search for the rare decay of the top quark that results in a charm quark and an SM Higgs boson, t -> ch, the existence of which would indicate a nonzero flavor-changing Yukawa coupling of the top quark to the Higgs boson. We place a 95% C.L. upper limit of 0.56% on B(t -> ch).

Exigências familiares e do trabalho: um equilíbrio necessário para a saúde de trabalhadores e organizações

This article aims, through a theoretical essay, to promote a reflection about the new roles played by people in families, at work and at the society in general. Based on papers and scientific bibliography, it broaches the changes at the contemporary society, linked to changes on world of work and family relationships, focused on the unbalance at family-work relation. Some current organizational initiatives were cited as plans of prevention and improvement of worker health, which affect their relations. It was considered the need of reconstruction of gender stereotypes and reducing the inequality of opportunity between people as focal points for changing a current scenario, which prevails in the lack of balance between requirements that can generate negative consequences both for health the individual and their families and for the organization.

Measurements of atmospheric neutrinos and antineutrinos in the MINOS far detector

This paper reports measurements of atmospheric neutrino and antineutrino interactions in the MINOS Far Detector, based on 2553 live-days (37.9 kton-years) of data. A total of 2072 candidate events are observed. These are separated into 905 contained-vertex muons and 466 neutrino-induced rock-muons, both produced by charged-current nu(mu) and (nu) over bar (mu) interactions, and 701 contained-vertex showers, composed mainly of charged-current nu(e) and (nu) over bar (e) interactions and neutral-current interactions. The curvature of muon tracks in the magnetic field of the MINOS Far Detector is used to select separate samples of nu(mu) and (nu) over bar (mu) events. The observed ratio of (nu) over bar (mu) to v(mu) events is compared with the Monte Carlo ( MC) simulation, giving a double ratio of R((nu) over bar/nu)data/R(nu) over bar/nu MC = 1.03 +/- 0.08(stat) +/- 0.08(syst). The v(mu) and (nu) over bar (mu) data are separated into bins of L/E resolution, based on the reconstructed energy and direction of each event, and a maximum likelihood fit to the observed L/E distributions is used to determine the atmospheric neutrino oscillation parameters. This fit returns 90% confidence limits of |Delta m(2)| = (1.9 +/- 0.4) x 10(-3) eV(2) and sin(2)2 theta > 0.86. The fit is extended to incorporate separate nu(mu) and (nu) over bar mu oscillation parameters, returning 90% confidence limits of |Delta m(2)| - |Delta(m) over bar (2)| = 0.6(-0.8)(+2.4) x 10(-3) eV(2) on the difference between the squared-mass splittings for neutrinos and antineutrinos.

Measurement of the forward-backward asymmetry of Z boson decays in electron-positron pairs with the ATLAS detector in proton-proton collisions at root out s = 7TeV at the LHC

In this thesis the measurement of the effective weak mixing angle wma in proton-proton collisions is described. The results are extracted from the forward-backward asymmetry (AFB) in electron-positron final states at the ATLAS experiment at the LHC. The AFB is defined upon the distribution of the polar angle between the incoming quark and outgoing lepton. The signal process used in this study is the reaction pp to zgamma + X to ee + X taking a total integrated luminosity of 4.8\,fb^(-1) of data into account. The data was recorded at a proton-proton center-of-mass energy of sqrt(s)=7TeV. The weak mixing angle is a central parameter of the electroweak theory of the Standard Model (SM) and relates the neutral current interactions of electromagnetism and weak force. The higher order corrections on wma are related to other SM parameters like the mass of the Higgs boson.rnrnBecause of the symmetric initial state constellation of colliding protons, there is no favoured forward or backward direction in the experimental setup. The reference axis used in the definition of the polar angle is therefore chosen with respect to the longitudinal boost of the electron-positron final state. This leads to events with low absolute rapidity have a higher chance of being assigned to the opposite direction of the reference axis. This effect called dilution is reduced when events at higher rapidities are used. It can be studied including electrons and positrons in the forward regions of the ATLAS calorimeters. Electrons and positrons are further referred to as electrons. To include the electrons from the forward region, the energy calibration for the forward calorimeters had to be redone. This calibration is performed by inter-calibrating the forward electron energy scale using pairs of a central and a forward electron and the previously derived central electron energy calibration. The uncertainty is shown to be dominated by the systematic variations.rnrnThe extraction of wma is performed using chi^2 tests, comparing the measured distribution of AFB in data to a set of template distributions with varied values of wma. The templates are built in a forward folding technique using modified generator level samples and the official fully simulated signal sample with full detector simulation and particle reconstruction and identification. The analysis is performed in two different channels: pairs of central electrons or one central and one forward electron. The results of the two channels are in good agreement and are the first measurements of wma at the Z resonance using electron final states at proton-proton collisions at sqrt(s)=7TeV. The precision of the measurement is already systematically limited mostly by the uncertainties resulting from the knowledge of the parton distribution functions (PDF) and the systematic uncertainties of the energy calibration.rnrnThe extracted results of wma are combined and yield a value of wma_comb = 0.2288 +- 0.0004 (stat.) +- 0.0009 (syst.) = 0.2288 +- 0.0010 (tot.). The measurements are compared to the results of previous measurements at the Z boson resonance. The deviation with respect to the combined result provided by the LEP and SLC experiments is up to 2.7 standard deviations.

Search for top quark decays t → qH with H → ƴƴ using the ATLAS detector

A search is performed for flavour-changing neutral currents in the decay of a top quark to an up-type (c, u) quark and a Higgs boson, where the Higgs boson decays to two photons. The proton-proton collision data set used corresponds to 4.7 fb−1 at √s = 7TeV and 20.3 fb−1 at √s = 8TeV collected by the ATLAS experiment at the LHC. Top quark pair events are searched for in which one top quark decays to qH and the other decays to bW. Both the hadronic and the leptonic decay modes of the W boson are used. No significant signal is observed and an upper limit is set on the t → qH branching ratio of 0.79% at the 95% confidence level. The corresponding limit on the tqH coupling combination qλ2t cH + λ2t uH is 0.17.

Proposta de modelo para o desenvolvimento de projetos minerais sustentáveis no Brasil.

A mineração brasileira, assim como todo o setor da industria de transformação, tem perdido competitividade ao longo do tempo, além disso o Brasil necessita tornar suas operações mais sustentáveis e agregar valor a sua produção industrial. A mineração é um setor onde esta questão se torna mais crítica, pois além de poder gerar forte impacto ambiental, a produção é fortemente baseada em commodities, com baixo valor agregado. Um dos caminhos para superar os obstáculos ao crescimento sustentável da mineração no Brasil é o desenvolvimento de projetos minerais inovadores. As condições estabelecidas pelo governo brasileiro para incentivo à inovação são muito abrangentes, práticas e atrativas; os recursos para financiamento são abundantes e os mecanismos para operacionalização extremamente profissionais. No entanto, na maioria das empresas brasileiras estão presentes a aversão ao risco, a falta das práticas de planejamento e de gestão de projetos e a visão de curto prazo focada na atuação corretiva, fatores que não favorecem o ambiente inovador nas empresas. Ou seja, o grande desafio para a mudança da mineração brasileira, tornando-a mais sustentável e competitiva, está na forma de pensar dos seus lideres; pois as condições existentes para desenvolvimento tecnológico estão disponíveis, mas as empresas necessitam aprender a utilizá-las. Este é um trabalho de pesquisa aplicada, que apresenta uma proposta de metodologia para desenvolvimento de projetos minerais sustentáveis, que foi utilizada por algumas empresas e obteve resultados muito positivos; com isto, é possível estabelecer um caminho que favoreça a mudança da cultura predominante, facilitando o desenvolvimento de inovações na mineração e contribuindo para o seu ganho de competitividade e sustentabilidade. A aplicação da metodologia proposta foi aplicada em um caso hipotético de mineração de ferro e os resultados foram muito positivos, demonstrando que o projeto inovador e sustentável seria muito mais competitivo que um tradicional, principalmente, em momentos de mercado em baixa.

Characterization of rock slopes through slope mass rating using 3D point clouds

Rock mass classification systems are widely used tools for assessing the stability of rock slopes. Their calculation requires the prior quantification of several parameters during conventional fieldwork campaigns, such as the orientation of the discontinuity sets, the main properties of the existing discontinuities and the geo-mechanical characterization of the intact rock mass, which can be time-consuming and an often risky task. Conversely, the use of relatively new remote sensing data for modelling the rock mass surface by means of 3D point clouds is changing the current investigation strategies in different rock slope engineering applications. In this paper, the main practical issues affecting the application of Slope Mass Rating (SMR) for the characterization of rock slopes from 3D point clouds are reviewed, using three case studies from an end-user point of view. To this end, the SMR adjustment factors, which were calculated from different sources of information and processes, using the different softwares, are compared with those calculated using conventional fieldwork data. In the presented analysis, special attention is paid to the differences between the SMR indexes derived from the 3D point cloud and conventional field work approaches, the main factors that determine the quality of the data and some recognized practical issues. Finally, the reliability of Slope Mass Rating for the characterization of rocky slopes is highlighted.

Efficient update and retrieval of objects in a multiresolution geospatial database

Many emerging applications benefit from the extraction of geospatial data specified at different resolutions for viewing purposes. Data must also be topologically accurate and up-to-date as it often represents real-world changing phenomena. Current multiresolution schemes use complex opaque data types, which limit the capacity for in-database object manipulation. By using z-values and B+trees to support multiresolution retrieval, objects are fragmented in such a way that updates to objects or object parts are executed using standard SQL (Structured Query Language) statements as opposed to procedural functions. Our approach is compared to a current model, using complex data types indexed under a 3D (three-dimensional) R-tree, and shows better performance for retrieval over realistic window sizes and data loads. Updates with the R-tree are slower and preclude the feasibility of its use in time-critical applications whereas, predictably, projecting the issue to a one-dimensional index allows constant updates using z-values to be implemented more efficiently.

CIVIL WAR SETTLEMENTS AND COMBATANTS’ BEHAVIORS: STRATEGY, PERCEPTION, AND REPUTATION

Three projects in my dissertation focus on the termination of internal conflicts based on three critical factors: a combatant’s bargaining strategy, perceptions of relative capabilities, and reputation for toughness. My dissertation aims to provide the relevant theoretical framework to understand war termination beyond the simple two-party bargaining context. The first project focuses on the government’s strategic use of peace agreements. The first project suggests that peace can also be designed strategically to create a better bargain in the near future by changing the current power balance, and thus the timing and nature of peace is not solely a function of overcoming current barriers to successful bargaining. As long as the government has no overwhelming capability to defeat all rebel groups simultaneously, it needs to keep multiple rebel groups as divided as possible. This strategic partial peace helps to deter multiple rebel groups from collaborating in the battlefield and increases the chances of victory against non-signatories. The second project deals with combatants’ perceptions of relative capabilities. While bargaining theories of war suggest that war ends when combatants share a similar perception about their relative capabilities, combatants’ perceptions about relative capabilities are not often homogeneous. While focusing on information problems, this paper examines when a rebel group underestimates the government’s supremacy in relative capabilities and how this heterogeneous perception about the power gap influences negotiated settlements. The third project deals with the tension between different types of reputations in the context of civil wars: 1) a reputation for resolve and 2) a reputation for keeping human rights standards. In the context of civil wars, the use of indiscriminate violence by the government is costly, and as such, it signals the government’s toughness (or resolve) to rebel groups. I argue that the rebels are more likely to accept the government’s offer when the government recently engaged in indiscriminate violence against civilians during the conflict. This effect, however, is conditional on the government’s international human rights reputation; suggesting that rebel groups interpret this violence as a signal particularly when the government does not have a penchant for attacking civilians in general.

A gestão de materiais numa empresa de telecomunicações

O mercado das telecomunicações e das tecnologias da informação é caraterizado por uma elevada instabilidade e competitividade. Deste modo, a aposta na diferenciação, no estabelecimento de vantagens competitivas e na melhoria contínua são pontos fulcrais para o sucesso das empresas tecnológicas. A empresa tecnológica PT Inovação e Sistemas, S.A. apresenta a necessidade de melhorar a gestão económica e física de materiais. Neste sentido, o presente Projeto propõe a introdução de melhorias ao nível da gestão de stocks e do armazém da referida empresa, segundo a realização de análises ABC, da determinação de stocks de segurança adequados e da redefinição do layout atual. Definem-se também critérios de alocação dos materiais no espaço de armazenagem e propõe-se a introdução de um sistema de controlo e rastreabilidade de materiais. Como fruto do presente trabalho, os resultados obtidos tiveram um impacto positivo, possibilitando um aumento da produtividade e da eficiência nos processos associados à gestão de materiais da organização.

Solid state micro and nanopore sensors for single entity detection

A general description of the work presented in this thesis can be divided into three areas of interest: micropore fabrication, nanopore modification, and their applications. The first part of the thesis is related to the novel, reliable, cost-effective, potable, mass-productive, robust, and ease of use micropore flowcell that works based on the RPS technique. Based on our first goal, which was finding an alternate materials and processes that would shorten production times while lowering costs and improving signal quality, the polyimide film was used as a substrate to create precise pores by femtosecond laser, and the resulting current blockades of different sizes of the nanoparticles were recorded. Based on the results, the device can detecting nano-sized particles by changing the current level. The experimental and theoretical investigation, scanning electron microscopy, and focus ion beam were performed to explain the micropore's performance. The second goal was design and fabrication of a leak-free, easy-to-assemble, and portable polymethyl methacrylate flowcell for nanopore experiments. Here, ion current rectification was studied in our nanodevice. We showed a self-assembly-based, controllable, and monitorable in situ Poly(l-lysine)- g-poly(ethylene glycol) coating method under voltage-driven electrolyte flow and electrostatic interaction between nanopore walls and PLL backbones. Using designed nanopore flowcell and in situ monolayer PLL-g-PEG functionalized 20±4 nm SiN nanopores, we observed non-sticky α-1 anti-trypsin protein translocation. additionally, we could show the enhancement of translocation events through this non-sticky nanopore, and also, estimate the volume of the translocated protein. In this study, by comparing the AAT protein translocation results from functionalized and non-functionalized nanopore we demonstrated the 105 times dwell time reduction (31-0.59ms), 25% amplitude enhancement (0.24-0.3 nA), and 15 times event’s number increase (1-15events/s) after functionalization in 1×PBS at physiological pH. Also, the AAT protein volume was measured, close to the calculated AAT protein hydrodynamic volume and previous reports.

Search for lepton-flavor-violating decays of the neutral kaon

The Fermilab KTeV experiment has searched for lepton-flavor-violating decays of the K(L) meson in three decay modes. We observe no events in the signal region for any of the modes studied, and we set the following upper limits for their branching ratios at the 90% C.L.: BR(K(L)->pi(0)mu(+/-)e(-/+))< 7.6x10(-11); BR(K(L)->pi(0)pi(0)mu(+/-)e(-/+))< 1.7x10(-10); BR(pi(0)->mu(+/-)e(-/+))< 3.6x10(-10). This result represents a factor of 82 improvement in the branching ratio limit for K(L)->pi(0)mu(+/-)e(-/+) and is the first reported limit for K(L)->pi(0)pi(0)mu(+/-)e(-/+).