Visualització de dades mèdiques

Treballs Finals de Grau d'Enginyeria Informàtica, Facultat de Matemàtiques, Universitat de Barcelona, Any: 2014, Director: Anna Puig Puig i Frederic Sampedro SantalóVisual analysis of medical volume datasets performed by medical experts provides valuable information in research and clinical settings such as radiology or nuclear medicine. Computer visualization methods seek to present to the user an informative display of a given dataset, trying to minimize both the computation time and the user interaction. The goal of this project is to analyze, design and implement a volume visualitzation system that proposes a new method to improve the visualitzation of segmented volume datasets. In this scenario, two common volume visualization methods included in commercial medical software are the Direct Volume Rendering (DVR), and the Maximum Intensity Projection (MIP). DVR allows to have a spatial context and MIP is an easy-­to­implement method. Both methods display good visualitzations but have several drawbacks. This project develops a new method called Maximum Intensity Difference Accumulation (MIDA) that exploits the data characteristics to generate good visualitzation results. The basic idea behind the MIDA approach is combining the advantatges of DVR and MIP and therefore provide an improved visualization framework with reduced limitations. Also, in this project an adaptation of the MIDA framework is proposed to visualize the volume in conjuntion with any segmentation mask of it. MIDA is a general method that can be applied to several types of volume datasets. In particular, this project focuses on the application of the proposed method in Positron Emission Tomography (PET) volumes obtained from the Nuclear Medicine Department at the H. Sant Pau. PET is a commonly used nuclear medicine diagnosis test to detect and quantify the presence of any tumor volume within a patient’s body, where physicians may also provide tumor segmentation masks. Visualization of segmented PET scans using our proposed MIDA­based system provided superior visual results with respect to DVR and MIDA approaches. A GPU implementation provides substancial runtime improvement with respect to a CPU approach, obtaining the real­time visualization needed in the clinical setting

Evidence based clinical practice guidelines : the Grupo Hospitalar Conceição experience

Objetivo: Descrever a metodologia que vem sendo empregada no GHC para o desenvolvimento de protocolos clínicos e de enfermagem, proporcionando um modelo que possa ser útil aos profissionais de saúde ao elaborarem protocolos embasados em evidências. Método: O processo de elaboração de protocolos clínicos e de enfermagem no GHC iniciou com o estabelecimento das diretrizes para elaboração e implementação de protocolos pela equipe técnica da GEP. Através dos critérios epidemiológicos de magnitude, transcendência e vulnerabilidade, obteve-se uma lista de assuntos prioritários para iniciar os trabalhos. Os autores de protocolos no GHC são os profissionais dos próprios Centros de Resultados. Eles estão sendo preparados para elaborarem protocolos de acordo com a padronização proposta pela GEP mediante cursos de capacitação. A GEP disponibiliza infra-estrutura e recursos humanos de apoio logístico para os autores. Resultado: Vários protocolos já foram elaborados, validados, homologados e estão sendo aplicados no GHC. Este artigo é, também, um dos resultados dos esforços da Comissão Técnica de Validação de Protocolos da GEP, bem como da experiência prática na orientação aos autores de protocolos no GHC. Além disso, a Prefeitura Municipal de Porto Alegre estabeleceu uma relação convenial com a GEP do GHC para capacitar um grupo de profissionais responsáveis pela elaboração de protocolos para a rede municipal de saúde. Os resultados dessa atividade já estão repercutindo através das primeiras reuniões de treinamento para implementação dos protocolos da Prefeitura. Conclusão: Este artigo apresenta a sistemática que estamos empregando no GHC para a elaboração de protocolos clínicos e de enfermagem embasados em evidências.Objective: Describe the methodology that has been used in the GHC to the development of the clinical and nursing protocols, proposing a model that can be useful to health professionals during the protocols development that has been based on evidence. Method: the elaboration of clinical and nursing protocols at GHC has begun with the establishment of the guidelines for elaboration and implementation of protocols by the research and teaching team (GEP). Through the criteria of magnitude, frequency and vulnerability it was possible to identify the priorities for the institution. The authors of protocols at GHC are professionals who have been elaborating protocols in accordance with the standardization proposal by GEP as a means of continued education. Result: some protocols have already been elaborated, and have been applied at GHC. This article shows the practical experience in order to develop the protocols at GHC. Moreover, the municipal health secretariat of Porto Alegre has established a contract with GEP of GHC to enable a group of professionals in charge for the elaboration of protocols to the health municipal network. The results of this activity already have beingechoed through the first meetings of training for implementation of the protocols for the primary health care. Conclusion: This Article Presents a Review on How to Develop Protocols that Have Been Used at GHC

Non-conventional yeast species for lowering ethanol content of wines

Rising sugar content in grape must, and the concomitant increase in alcohol levels in wine, are some of the main challenges affecting the winemaking industry nowadays. Among the several alternative solutions currently under study, the use of nonconventional yeasts during fermentation holds good promise for contributing to relieve this problem. Non-Saccharomyces wine yeast species comprise a high number or species, so encompassing a wider physiological diversity than Saccharomyces cerevisiae. Indeed, the current oenological interest of these microorganisms was initially triggered by their potential positive contribution to the sensorial complexity of quality wines, through the production of aroma and other sensory-active compounds. This diversity also involves ethanol yield on sugar, one of the most invariant metabolic traits of S. cerevisiae. This review gathers recent research on non-Saccharomyces yeasts, aiming to produce wines with lower alcohol content than those from pure Saccharomyces starters. Critical aspects discussed include the selection of suitable yeast strains (considering there is a noticeable intra-species diversity for ethanol yield, as shown for other fermentation traits), identification of key environmental parameters influencing ethanol yields (including the use of controlled oxygenation conditions), and managing mixed fermentations, by either the sequential or simultaneous inoculation of S. cerevisiae and non-Saccharomyces starter cultures. The feasibility, at the industrial level, of using non-Saccharomyces yeasts for reducing alcohol levels in wine will require an improved understanding of the metabolism of these alternative yeast species, as well as of the interactions between different yeast starters during the fermentation of grape must.Experimental work by researchers from ICVV is supported by the Spanish Government trough MINECO and FEDER funds: MINECO AGL2012-32064 and AGL2015-63629-R grants, INIA RM2012-00007-00-00 grant, MINECO RTC-2014-2186-2 grant, MINECO training contract for AR, MINECO Formación Postdoctoral contract for JC. Experimental work by the authors from Polytechnic University of Marche is supported by Ricerca Scientifica di Ateneo RSA2015.Peer Reviewe

Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

Measurement of the polarisation of W bosons produced with large transverse momentum in pp collisions at sqrt(s) = 7 TeV with the ATLAS experiment

This paper describes an analysis of the angular distribution of W->enu and W->munu decays, using data from pp collisions at sqrt(s) = 7 TeV recorded with the ATLAS detector at the LHC in 2010, corresponding to an integrated luminosity of about 35 pb^-1. Using the decay lepton transverse momentum and the missing transverse energy, the W decay angular distribution projected onto the transverse plane is obtained and analysed in terms of helicity fractions f0, fL and fR over two ranges of W transverse momentum (ptw): 35 < ptw < 50 GeV and ptw > 50 GeV. Good agreement is found with theoretical predictions. For ptw > 50 GeV, the values of f0 and fL-fR, averaged over charge and lepton flavour, are measured to be : f0 = 0.127 +/- 0.030 +/- 0.108 and fL-fR = 0.252 +/- 0.017 +/- 0.030, where the first uncertainties are statistical, and the second include all systematic effects.Comment: 19 pages plus author list (34 pages total), 9 figures, 11 tables, revised author list, matches European Journal of Physics C versio

Observation of a new chi_b state in radiative transitions to Upsilon(1S) and Upsilon(2S) at ATLAS

The chi_b(nP) quarkonium states are produced in proton-proton collisions at the Large Hadron Collider (LHC) at sqrt(s) = 7 TeV and recorded by the ATLAS detector. Using a data sample corresponding to an integrated luminosity of 4.4 fb^-1, these states are reconstructed through their radiative decays to Upsilon(1S,2S) with Upsilon->mu+mu-. In addition to the mass peaks corresponding to the decay modes chi_b(1P,2P)->Upsilon(1S)gamma, a new structure centered at a mass of 10.530+/-0.005 (stat.)+/-0.009 (syst.) GeV is also observed, in both the Upsilon(1S)gamma and Upsilon(2S)gamma decay modes. This is interpreted as the chi_b(3P) system.Comment: 5 pages plus author list (18 pages total), 2 figures, 1 table, corrected author list, matches final version in Physical Review Letter

Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS

We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb^-1 collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutralino lifetime. Limits are presented for different squark and neutralino masses, enabling extension of the limits to a variety of other models.Comment: 8 pages plus author list (20 pages total), 8 figures, 1 table, final version to appear in Physics Letters

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde