Determinação da capacidade pulmonar total: pletismografia versus método de diluição do hélio em respiração única após teste broncodilatador

OBJECTIVE: Total lung capacity (TLC) can be measured using body plethysmography,single-breath helium or RX planimetry. Body plethysmography is the goldstandard test,allowing comparison with other methods. The single breath helium method (SBHe),when used in association with CO2diffusing capacity, can estimate lung volumes inpatients with airway flow obstruction. The aim of the present study is to evaluate if TLCmeasured with SBHe after treatment with bronchodilator is similar to that obtained frombody plethysmography.MATERIALS AND METHODS: The sample included 155 adult patients submitted topulmonary function testing including lung volumes at the Pulmonary Physiology Unit,Pulmonary Department at Hospital de Clínicas de Porto Alegre. The patients were placedin two groups: one group underwent SBHe with bronchodilator, and the other group wassubmitted to SBHe without bronchodilator. Afterwards, each group was subdivided intotwo subgroups: normal patients and patients with airway obstruction.RESULTS: The TLC results obtained with the body plethysmography technique weregreater than the alternative methods for all groups. In the group without bronchodilatortreatment, there was a median difference of 934 ml (CI 95% = 657 ml – 1210 ml;P<0.001) for normal patients, and a median difference of 1679 ml (95% Cl = 1289ml –2069 ml; P<0.001) for patients with airway obstruction. While bronchodilator treatmentwas used, the median difference for normal patients with airway obstruction was 1751ml (95% Cl 1516 – 1985 ml; P<0.001).CONCLUSIONS: The results showed that treatment with bronchodilator did not makeTLC measurements similar when SBHe was compared to body plethysmography, neitherfor normal patients nor for patients with airway obstruction; this leads to the conclusionthat SBHe is not a reliable test for TLC measurements.OBJETIVO: A capacidade pulmonar total (CPT) pode ser medida através dapletismografia, de testes de diluição de gases e por planimetria radiográfica. Apletismografia constitui-se no padrão aúreo, base de comparação para os outrostestes. O teste de respiração única com hélio (TDHe), realizado em conjunto com adeterminação da capacidade de difusão com monóxido de carbono, subdimensionao volume pulmonar em pacientes com obstrução ao fluxo aéreo. O objetivo dopresente trabalho foi o de avaliar se o TDHe após broncodilatador aproximaria ovalor da CPT obtido pelo TDHe com o da pletismografia, otimizando o teste erotinizando-o após broncodilatador.MATERIAIS E MÉTODOS: Foram estudados 155 pacientes adultos, que realizaramtestes com determinação de volumes na Unidade de Fisiologia Pulmonar do Serviçode Pneumologia do Hospital de Clínicas de Porto Alegre. Dividiu-se os pacientes emdois grupos: os que foram submetidos ao TDHe sem broncodilatador e os que fizeramTDHe com broncodilatador. Cada grupo foi subdividido em dois subgrupos: normaise obstrutivos.RESULTADOS: Os valores da CPT obtidos com pletismografia foram superiores emtodos os grupos. No grupo sem broncodilatador, os valores de CPT tiveram umadiferença média de 934 ml (IC 95% de 657 a 1210; P<0,001) nos normais e de 1679 ml(IC 95% de 1289 a 2069; P<0,001) nos obstrutivos. Com o broncodilatador, a diferençamédia dos pacientes normais foi de 1111 ml (IC 95% de 706 a 1515; P<0,001) e nosobstrutivos a diferença foi de 1751 ml (IC 95% de 1516 a 1985; P<0,001).CONCLUSÕES: Os resultados demonstraram que o uso do broncodilatador nãoaproximou os valores da CPT do TDHe aos da pletismografia, tanto em indivíduosnormais como naqueles com doença obstrutiva das vias aéreas. O TDHE não seconstitui em teste fidedigno para determinação de volumes pulmonares absolutos

Education plays a greater role than age in cognitive test performance among participants of the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Background: Brazil has gone through fast demographic, epidemiologic and nutritional transitions and, despite recent improvements in wealth distribution, continues to present a high level of social and economic inequality. The ELSA-Brasil, a cohort study, aimed at investigating cardiovascular diseases and diabetes, offers a great opportunity to assess cognitive decline in this aging population through time-sequential analyses drawn from the same battery of tests over time. The purpose of this study is to analyze the influence of sex, age and education on cognitive tests performance of the participants at baseline. Methods: Analyses pertain to 14,594 participants with aged 35 to 74 years, who were functionally independent and had no history of stroke or use of neuroleptics, anticonvulsants, cholinesterase inhibitors or antiparkinsonian agents. Mean age was 52.0 ± 9.0 years and 54.2 % of participants were women. Cognitive tests included the word memory tests (retention, recall and recognition), verbal fluency tests (VFT, animals and letter F) and Trail Making Test B. Multivariable linear regression analysis was used to determine the influence of sociodemographic characteristics on the distribution of the final score of each test. Results: Women had significant and slightly higher scores than men in all memory tests and VFT, but took more time to perform Trail B. Reduced performance in all tests was seen with an increase age and, more importantly, with decrease level of education. The word list and VFT scores decreased at about one word for every 10 years of age whereas higher-educated participants scored four words more on the word list test, and six or seven more correct words on VFT, when compared to lower-educated participants. Additionally, the oldest and less educated participants showed significant lower response rates in all tests. Conclusions: The higher influence of education than age in this Brazilian population reinforce the need for caution in analyzing and diagnosing cognitive impairments based on traditional cognitive tests and the importance of searching for education-free cognitive tests, especially in low and middle-income countries

Consistency analysis of a nonbirefringent Lorentz-violating planar model

In this work analyze the physical consistency of a nonbirefringent Lorentz-violating planar model via the analysis of the pole structure of its Feynman propagators. The nonbirefringent planar model, obtained from the dimensional reduction of the CPT-even gauge sector of the standard model extension, is composed of a gauge and a scalar fields, being affected by Lorentz-violating (LIV) coefficients encoded in the symmetric tensor $\kappa_{\mu\nu}$. The propagator of the gauge field is explicitly evaluated and expressed in terms of linear independent symmetric tensors, presenting only one physical mode. The same holds for the scalar propagator. A consistency analysis is performed based on the poles of the propagators. The isotropic parity-even sector is stable, causal and unitary mode for $0\leq\kappa_{00}<1$. On the other hand, the anisotropic sector is stable and unitary but in general noncausal. Finally, it is shown that this planar model interacting with a $\lambda|\varphi|^{4}-$Higgs field supports compactlike vortex configurations.Comment: 11 pages, revtex style, final revised versio

Compressed Pairings

Pairing-based cryptosystems rely on bilinear non-degenerate maps called pairings, such as the Tate and Weil pairings defined over certain elliptic curve groups. In this paper we show how to compress pairing values, how to couple this technique with that of point compression, and how to benefit from the compressed representation to speed up exponentiations involving pairing values, as required in many pairing based protocols

Search for Higgs bosons decaying to tautau pairs in ppbar collisions at sqrt(s) = 1.96 TeV

We present a search for the production of neutral Higgs bosons decaying into tautau pairs in ppbar collisions at a center-of-mass energy of 1.96 TeV. The data, corresponding to an integrated luminosity of 5.4 fb-1, were collected by the D0 experiment at the Fermilab Tevatron Collider. We set upper limits at the 95% C.L. on the product of production cross section and branching ratio for a scalar resonance decaying into tautau pairs, and we then interpret these limits as limits on the production of Higgs bosons in the minimal supersymmetric standard model (MSSM) and as constraints in the MSSM parameter space.Comment: 7 pages, 5 figures, submitted to PL

Measurement of three-jet differential cross sections d sigma-3jet / d M-3jet in p anti-p collisions at sqrt(s)=1.96 TeV

We present the first measurement of the inclusive three-jet differential cross section as a function of the invariant mass of the three jets with the largest transverse momenta in an event in p anti-p collisions at sqrt(s) = 1.96 TeV. The measurement is made in different rapidity regions and for different jet transverse momentum requirements and is based on a data set corresponding to an integrated luminosity of 0.7 fb^{-1} collected with the D0 detector at the Fermilab Tevatron Collider. The results are used to test the three-jet matrix elements in perturbative QCD calculations at next-to-leading order in the strong coupling constant. The data allow discrimination between parametrizations of the parton distribution functions of the proton.Comment: 10 pages, 4 figures, 2 tables, submitted to Phys. Lett. B, corrected chi2 values for NNPD

Search for pair production of the scalar top quark in muon+tau final states

We present a search for the pair production of scalar top quarks ($\tilde{t}_{1}$), the lightest supersymmetric partners of the top quarks, in $p\bar{p}$ collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 $fb^{-1}$} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a $b$ quark, a charged lepton, and a scalar neutrino ($\tilde{\nu}$). We investigate final states arising from $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu}$ and $\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}$. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the ($m_{\tilde{t}_{1}}$,$m_{\tilde{\nu}}$) plane.Comment: Submitted to Phys. Lett.

Measurements of inclusive W+jets production rates as a function of jet transverse momentum in ppbar collisions at sqrt{s}=1.96 TeV

This Letter describes measurements of inclusive W (--> e nu) + n jet cross sections (n = 1-4), presented as total inclusive cross sections and differentially in the nth jet transverse momentum. The measurements are made using data corresponding to an integrated luminosity of 4.2 fb-1 collected by the D0 detector at the Fermilab Tevatron Collider, and achieve considerably smaller uncertainties on W +jets production cross sections than previous measurements. The measurements are compared to next-to-leading order perturbative QCD (pQCD) calculations in the n =1-3 jet multiplicity bins and to leading order pQCD calculations in the 4-jet bin. The measurements are generally in agreement with pQCD predictions, although certain regions of phase space are identified where the calculations could be improved

Measurement of spin correlation in ttbar production using dilepton final states

We measure the correlation between the spin of the top quark and the spin of the anti-top quark in (ttbar -> W+ W- b bbar -> l+ nu b l- nubar bbar) final states produced in ppbar collisions at a center of mass energy sqrt(s)=1.96 TeV, where l is an electron or muon. The data correspond to an integrated luminosity of 5.4 fb-1 and were collected with the D0 detector at the Fermilab Tevatron collider. The correlation is extracted from the angles of the two leptons in the t and tbar rest frames, yielding a correlation strength C= 0.10^{+0.45}_{-0.45}, in agreement with the NLO QCD prediction within two standard deviations, but also in agreement with the no correlation hypothesis.Comment: 10 pages, 3 figures, submitted to PL

Measurement of the ttbar production cross section using dilepton events in ppbar collisions

We present a measurement of the ttbar production cross section sigma(ttbar) in ppbar collisions at sqrt{s} = 1.96 TeV using 5.4 fb-1 of integrated luminosity collected with the D0 detector. We consider final states with at least two jets and two leptons (ee, emu, mumu), and events with one jet for the the emu final state as well. The measured cross section is sigma(ttbar)= 7.36 +0.90-0.79 (stat + syst) pb. This result combined with the cross section measurement in the lepton + jets final state yields sigma(ttbar)=7.56 +0.63-0.56 (stat + syst) pb, which agrees with the standard model expectation. The relative precision of 8% of this measurement is comparable to the latest theoretical calculations.Comment: 9 pages, published in Phys. Lett.