20 research outputs found
Propriedades quĂmicas de uma Terra Roxa Estruturada influenciadas pela cobertura vegetal de inverno e pela adubação orgĂąnica e mineral
O presente trabalho teve por objetivo avaliar a influĂȘncia da cobertura vegetal de inverno, constituĂda de uma associação de aveia preta (Avena strigosa Schreb) com nabo forrageiro (Raphanus sativus L.), da adubação orgĂąnica com esterco de aves e da adubação mineral sobre propriedades quĂmicas de uma Terra Roxa Estruturada do estado de Santa Catarina. As anĂĄlises foram realizadas em amostras de solo coletadas em agosto de 1994 e janeiro de 1995, nas profundidades de 0-10, 10-20 e 20-30 cm, em um experimento iniciado em 1990. Observou-se que a cobertura vegetal de inverno mostrou-se eficiente na manutenção de nutrientes, especialmente o potĂĄssio, e dos nĂveis de carbono orgĂąnico, dentro dos limites da camada arĂĄvel. O uso de adubo orgĂąnico proporcionou acĂșmulo de nutrientes no solo, enquanto os adubos organomineral e mineral mostraram tendĂȘncia de redução, principalmente dos nĂveis de potĂĄssio do solo
Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at âsNN = 5.02 TeV with the LHCb detector
Flow harmonic coefficients,
v
n
, which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02
TeV
. The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features
Helium identification with LHCb
The identification of helium nuclei at LHCb is achieved using a method based on measurements of ionisation losses in the silicon sensors and timing measurements in the Outer Tracker drift tubes. The background from photon conversions is reduced using the RICH detectors and an isolation requirement. The method is developed using pp collision data at â(s) = 13 TeV recorded by the LHCb experiment in the years 2016 to 2018, corresponding to an integrated luminosity of 5.5 fb-1. A total of around 105 helium and antihelium candidates are identified with negligible background contamination. The helium identification efficiency is estimated to be approximately 50% with a corresponding background rejection rate of up to O(10^12). These results demonstrate the feasibility of a rich programme of measurements of QCD and astrophysics interest involving light nuclei
Curvature-bias corrections using a pseudomass method
Momentum measurements for very high momentum charged particles, such as muons from electroweak vector boson decays, are particularly susceptible to charge-dependent curvature biases that arise from misalignments of tracking detectors. Low momentum charged particles used in alignment procedures have limited sensitivity to coherent displacements of such detectors, and therefore are unable to fully constrain these misalignments to the precision necessary for studies of electroweak physics. Additional approaches are therefore required to understand and correct for these effects. In this paper the curvature biases present at the LHCb detector are studied using the pseudomass method in proton-proton collision data recorded at centre of mass energy â(s)=13 TeV during 2016, 2017 and 2018. The biases are determined using ZâÎŒ + ÎŒ - decays in intervals defined by the data-taking period, magnet polarity and muon direction. Correcting for these biases, which are typically at the 10-4 GeV-1 level, improves the ZâÎŒ + ÎŒ - mass resolution by roughly 18% and eliminates several pathological trends in the kinematic-dependence of the mean dimuon invariant mass
Study of CP violation in B0 â DKâ(892)0 decays with D â KÏ(ÏÏ), ÏÏ(ÏÏ), and KK final states
A measurement of CP-violating observables associated with the interference
of B0 â D0Kâ
(892)0 and B0 â DÂŻ 0Kâ
(892)0 decay amplitudes is performed in the
D0 â KâÏ
±(Ï
+Ï
â), D0 â Ï
+Ï
â(Ï
+Ï
â), and D0 â K+Kâ fnal states using data collected
by the LHCb experiment corresponding to an integrated luminosity of 9 fbâ1
. CP-violating
observables related to the interference of B0
s â D0KÂŻ â
(892)0 and B0
s â DÂŻ 0KÂŻ â
(892)0 are also
measured, but no evidence for interference is found. The B0 observables are used to constrain
the parameter space of the CKM angle Îł and the hadronic parameters r
DKâ
B0 and ÎŽ
DKâ
B0 with
inputs from other measurements. In a combined analysis, these measurements allow for four
solutions in the parameter space, only one of which is consistent with the world average
Embolia gassosa paradossa in corso di C.P.R.E. Valutazioni medico-legali
Gli Autori discutono sul fenomeno embolico gassoso in corso di CPRE con esito mortale. Previa disamina della letteratura scientifica internazionale, sono affrontati gli aspetti eziopatogenetici, clinici, radiologici ed anatomo-patologici. Sono quindi discussi gli aspetti medico-legali in tema di possibili profili di responsabilit\ue0 sanitaria
Lethal cardiac amyloidosis: Microscopic differential diagnosis with microfibrillar cardiomyopathy in a forensic case
In a previous study, we presented a case of an elderly woman\u2019s sudden death, in which microscopic examinations
showed intramyocardial eosinophilic material suspected for amyloid, but not definable as such to the classic
Congo Red staining. To overcome the arisen interpretative and diagnostic difficulties, we experimentally modified
the classic Congo Red staining, using a specific one for corpse. The finding of a low-intensity positivity allowed us
to formulate a very likely diagnosis of occult lethal cardiac amyloidosis.
However, this low-intensity positivity obtained after having applied this experimental method for the first time
and in only one case, as well as the existence of the rare pathology known as microfibrillar cardiomyopathy,
which may be related to the observed microscopic findings, have forced us to investigate the correctness of the
diagnosis. For this purpose, we performed in-depth investigations with sodium sulphate-Alcian Blue (SAB) staining
and immunohistochemistry. Thanks to them, the amyloid nature of the intramyocardial material was confirmed
and has been proved not only the reliability of our experimentally modified technique, but also the appropriateness
of the diagnosis previously formulated. Therefore, the supposed involvement of the microfibrillar cardiomyopathy
was excluded
Desenvolvimento de uma escala para medir o potencial empreendedor utilizando a Teoria da Resposta ao Item (TRI) Development of a scale to measure the entrepreneurial potential using the Item Response Theory (IRT)
Diversas variĂĄveis estĂŁo relacionadas ao desenvolvimento da atividade empreendedora, verifica-se, entre elas, a importĂąncia do agente empreendedor. Dos estudos que contribuem para o seu entendimento, este segue a linha que defende que o empreendedor tem caracterĂsticas e traços de personalidade singulares em relação Ă população, os quais sĂŁo propĂcios ao sucesso do empreendedorismo. O objetivo deste trabalho Ă© desenvolver uma escala para medir o potencial empreendedor utilizando a Teoria da Resposta ao Item. Foi utilizado o modelo logĂstico de dois parĂąmetros da TRI. As estimativas dos parĂąmetros foram obtidas a partir da amostra com 764 pessoas que responderam a um instrumento composto por 103 itens. A curva de informação e do erro padrĂŁo do teste e a interpretação qualitativa de nĂveis da escala permitiram determinar o intervalo mais apropriado para utilização do instrumento. Os resultados mostraram que a escala Ă© mais adequada para avaliar indivĂduos com baixo atĂ© moderadamente alto potencial empreendedor. Por isso, sugere-se que novos itens sejam incorporados ao instrumento para mensurar e interpretar nĂveis ainda mais elevados. A Teoria da Resposta ao Item permite que novos itens sejam calibrados a fim de mensurar os empreendedores com alto potencial empreendedor, aproveitando os dados jĂĄ obtidos.<br>Several variables are related to the development of entrepreneurial activities. An important one among them is the entrepreneurial agent. This study is one of many that contribute to the understanding of the entrepreneurial agent. In its line of thought, it upholds the idea that the entrepreneur has characteristics and personality traits that stand out from the general population and that are favorable to the success of the entrepreneurship. This study aims at developing a measurement scale for entrepreneurial potential using the Item Response Theory. The items were generated by Santos (2008) based on a theoretical model referenced in theories of entrepreneur's personality. The samples include 664 undergraduate and graduate students of Brazilian universitie, and 100 entrepreneurs of the state of Alagoas. A two- parameter logistic IRT model was used. The parameter estimates were obtained from a sample of 764 people who responded to an instrument containing 103 items. The information and the standard error curves and the qualitative interpretation of the scale levels allowed us to determine the most appropriate range for the instrument use. The results showed that the scale is most adequate to evaluate individuals with low to moderately high entrepreneurial potential. Therefore, it is suggested that new items are incorporated into the instrument to measure and interpret even higher levels. The Item Response Theory allows the calibration of new items to measure entrepreneurs with high entrepreneurial potential using previously obtained data