In this work, deep learning techniques for brain age prediction from magnetic resonance images are investigated, aiming to assist in the identification of biomarkers of the natural aging process. The identification of biomarkers is useful for detecting an early-stage neurodegenerative process, as well as for predicting age-related or non-age-related cognitive decline. Two techniques are implemented and compared in this work: a 3D Convolutional Neural Network applied to the volumetric image and a 2D Convolutional Neural Network applied to slices from the axial plane, with subsequent fusion of individual predictions. The best result was obtained by the 2D model, which achieved a mean absolute error of 3.83 years. -- Neste trabalho são investigadas técnicas de aprendizado profundo para a predição da idade cerebral a partir de imagens de ressonância magnética, visando auxiliar na identificação de biomarcadores do processo natural de envelhecimento. A identificação de biomarcadores é útil para a detecção de um processo neurodegenerativo em estágio inicial, além de possibilitar prever um declínio cognitivo relacionado ou não à idade. Duas técnicas são implementadas e comparadas neste tra
Neste artigo discutimos uma nova demonstracao experimental da independencia das propriedades dos corpos (massa, composicao quimica, forma, etc.) na queda livre. Eh uma das experiencias mais simples, porem uma das mais importantes da Mecanica, tendo sido realizada e repensada repetidamente por diversos cientistas tais como Galileu e Newton. Nossa versao eh introduzir dentro de uma garrafa fechada e transparente uma pena e uma pedra observando a queda simultanea destes corpos. Por nao haver a necessidade de produzir vacuo, esta versao pode ser repetida por qualquer aluno e professor de ensino medio e universitario em qualquer ambiente, evidenciando sua viabilidade e aplicabilidade na sala de aula. English version of abstract: In this paper we discuss a new experimental demonstration of the independence of the properties of bodies (mass, chemical composition, shape, etc) in free fall. This is one of the simplest experiments in mechanics, though one of the most important ones, having been repeatedly carried out and rethought by several scientists such as Galileo and Newton. Our version of this famous experiment uses one bottle (closed and transparent), in which we introduce a feather a
The granting process of all credit institutions rejects applicants who seem risky regarding the repayment of their debt. A credit score is calculated and associated with a cut-off value beneath which an applicant is rejected. Developing a new score implies having a learning dataset in which the response variable good/bad borrower is known, so that rejects are de facto excluded from the learning process. We first introduce the context and some useful notations. Then we formalize if this particular sampling has consequences on the score's relevance. Finally, we elaborate on methods that use not-financed clients' characteristics and conclude that none of these methods are satisfactory in practice using data from Crédit Agricole Consumer Finance. ----- Un système d'octroi de crédit peut refuser des demandes de prêt jugées trop risquées. Au sein de ce système, le score de crédit fournit une valeur mesurant un risque de défaut, valeur qui est comparée à un seuil d'acceptabilité. Ce score est construit exclusivement sur des données de clients financés, contenant en particulier l'information `bon ou mauvais payeur', alors qu'il est par la suite appliqué à l'ensemble des demandes. Un tel sc
Galaxy clusters are important cosmological probes since their abundance and spatial distribution are directly linked to structure formation on large scales. The principal uncertainty source on the cosmological parameter constraints concerns the cluster mass estimation from mass proxies. In addition, future surveys will provide a large amount of data, requiring an improvement in the accuracy of other elements used in the construction of cluster likelihoods. Therefore, accurate modeling of the mass-observable relations and reducing the effect of different systematic errors are fundamental steps for the success of cluster cosmology. In this work, we briefly review the abundance of galaxy clusters and discuss many sources of uncertainty. Os aglomerados de galáxias são importantes sondas cosmológicas, já que a abundância e a distribuição espacial desses objetos estão diretamente ligadas à formação de estruturas em grandes escalas. A maior fonte de incerteza nas restrições de parâmetros cosmológicos é originária das estimativas das massas dos aglomerados a partir da relação massa-observável. Além disso, os próximos grandes levantamentos fornecerão uma grande quantidade de dados, requeren
Mediante el estudio de propiedades geométricas de los sistemas C-ortocéntricos, relacionadas con las nociones de ortogonalidad (Birkhoff, isósceles, cordal), bisectriz (Busemann, Glogovskij) y línea soporte a una circunferencia, se muestran nueve caracterizaciones de euclidianidad para planos de Minkowski arbitrarios. Tres de estas generalizan caracterizaciones dadas para planos de Minkowski estrictamente convexos en [8, 9], y las otras seis son nuevos aportes sobre el tema. -- By studying geometric properties of C-orthocentric systems related to the notions of orthogonality (Birkhoff, isosceles, chordal), angular bisector (Busemann, Glogovskij) and support line to a circumference, nine characterizations of the Euclidean plane are shown for arbitrary Minkowski planes. Three of these generalized characterizations given for strictly convex Minkowski planes in [8, 9], and the other six are new contributions on the subject.
The first search for the $B_s^0\rightarrow K^-π^+γ$ decay in the range $796<m(K^-π^+)<1800\,\text{MeV/}c^2$ is performed using data from proton-proton collisions collected by the LHCb experiment at centre-of-mass energies of 7, 8, and 13 TeV, corresponding to an integrated luminosity of 9 fb$^{-1}$. The photons are reconstructed through their conversion into an electron-positron pair, which significantly improves the mass resolution of the reconstructed decays with respect to decays with an unconverted photon. A signal excess with a significance of 3.5 standard deviations is measured, constituting the first experimental evidence for this decay. In the range $796<m(K^-π^+)<996\,\text{MeV/}c^2$, the ratio ${\cal R}$ between the branching fractions of the signal decay and the favoured $\kern 0.18em\overline{\kern -0.18em B}{}^0\rightarrow K^- π^+γ$ decay is measured to be ${\cal R} = (3.7\pm1.2\pm0.4)\times10^{-2}$ where the first uncertainty is statistical and the second is systematic. This measurement is consistent with the value predicted in the Standard Model. In the range $996<m(K^-π^+)<1800\,\text{MeV/}c^2$, the ratio ${\cal R} = (0.2\pm2.7\pm1.3)\times10^{-2}$
A measurement of the CKM angle $γ$ and related strong-phase parameters is performed using a novel, model-independent approach in ${B^{\pm}\rightarrow D(\rightarrow K^{0}_{\rm S} h^{\prime+}h^{\prime-}) h^{\pm}}$ decays, where $h^{(\prime)} \equiv π, K$. The analysis uses a joint data sample of electron-positron collisions collected by the BESIII experiment at the Beijing Electron-Positron Collider II during 2010--2011 and 2021--2022, corresponding to an integrated luminosity of 8 fb$^{-1}$, and proton-proton collisions collected by the LHCb experiment at the Large Hadron Collider during 2011--2018, corresponding to an integrated luminosity of 9 fb$^{-1}$. The two datasets are analyzed simultaneously by applying per-event weights based on the amplitude variation over the $D$-decay phase space to enhance the sensitivity to $C\!P$-violating observables. The CKM angle $γ$ is determined to be $γ= (71.3\pm 5.0)^{\circ}$, which constitutes the most precise single measurement to date.
The first searches for $B^0\to K^+π^-τ^+τ^-$ and $B^0_s\to K^+K^-τ^+τ^-$ decays at the LHCb experiment are conducted with $pp$ collision data corresponding to an integrated luminosity of $5.4\textrm{ fb}^{-1}$. The tau leptons are reconstructed using the $τ^+\to μ^+\overlineν_τν_μ$ decay and the results are presented in bins of $K^+π^-$ or $K^+K^-$ mass. No signal is observed and upper limits are set on the branching fractions. The searches result in the first upper limits for $B^0\to K^+π^-τ^+τ^-$ decays outside the $K^*(892)^0$ region in $K^+π^-$ mass and the first limits for $B^0_s\to K^+K^-τ^+τ^-$ decays. The searches are recast into limits on the decays $B^0\to K^*(892)^0τ^+τ^-$ and $B^0_s\to φ(1020)τ^+τ^-$, yielding $2.8\times10^{-4}$ ($2.5\times10^{-4}$) and $4.7\times10^{-4}$ ($4.1\times10^{-4}$) at the $95\%$ ($90\%$) confidence level, respectively. For the decay $B^0\to K^*(892)^0τ^+τ^-$, this result improves on the current best upper limit by an order of magnitude.
The normalised decay rate of $B^+ \to J/ψ(\to μ^+μ^-) K^+$ is measured as a function of the lepton helicity angle using a data sample corresponding to an integrated luminosity of $1.1 \text{fb}^{-1}$ collected during October 2024 with the upgraded (Upgrade I) LHCb detector. This angular distribution can be parameterised by two coefficients, the forward-backward asymmetry, $A_{FB}$, and the flatness parameter, $F_{H}$, whose values are constrained by conservation of angular momentum. These coefficients are measured both integrated and differentially across various kinematic and detector-response variables, and the results are found to be in good agreement with expectations. These measurements show that the detector response of the LHCb Upgrade I experiment is understood to the precision required to reliably extract the angular coefficients associated with rare $b \to s μ^+μ^-$ and $b \to d μ^+μ^-$ transitions, which are particularly sensitive to physics beyond the Standard Model.
The first observation of the $χ_{c1}(3872)\rightarrow J\mskip -3mu/\mskip -2muψμ^+μ^-$ decay is reported using proton-proton collision data recorded with the LHCb detector corresponding to an integrated luminosity of $9fb^{-1}$. The decay mode is observed for the first time, with a significance of $6.5σ$. Its branching fraction is measured relative to the $χ_{c1}(3872)\rightarrow J\mskip -3mu/\mskip -2muψπ^+π^-$ decay mode \begin{align*} \frac{\cal{BF}(χ_{c1}(3872)\rightarrow J\mskip -3mu/\mskip -2muψμ^+μ^-)}{\cal{BF}(χ_{c1}(3872)\rightarrow J\mskip -3mu/\mskip -2muψπ^+π^-)} = \left(1.68\pm 0.32\pm 0.05\right)\times10^{-3}, \end{align*} where the first uncertainty includes both statistical contributions and systematic contributions which are uncorrelated between data-taking periods, and the second represents the systematic contributions that are correlated between data-taking periods.
Presents a differentiated teaching proposal that allows the student to be the agent in the construction of knowledge, overcoming the difficulties that Mathematics presents. Aiming to understand how the use of statistical tools can contribute to the improvement of the teaching-learning process and the construction of statistical knowledge, studied with students from the University Campus of Rondonopolis/UFMT. In order to reach the proposed objective, an analysis was carried out about the didactic activities in the teaching of basic statistics in which a qualitative-quantitative approach was chosen, focusing on everyday life, with the use of software, creation and simulation of models, as well as seeking to establish the frequency of the students' attitude, through questionnaires and a four-point Likert Scale, seeking data that would trace the profile of the actors involved that would help in the understanding of the planned didactic activities. The study is justified by the lack of methodological theoretical references on the subject in question. Didactic activities of Statistics were organized, whose applications took place in alternating classes, being traditional lectures and pra
The LHCb upgrade represents a major change of the experiment. The detectors have been almost completely renewed to allow running at an instantaneous luminosity five times larger than that of the previous running periods. Readout of all detectors into an all-software trigger is central to the new design, facilitating the reconstruction of events at the maximum LHC interaction rate, and their selection in real time. The experiment's tracking system has been completely upgraded with a new pixel vertex detector, a silicon tracker upstream of the dipole magnet and three scintillating fibre tracking stations downstream of the magnet. The whole photon detection system of the RICH detectors has been renewed and the readout electronics of the calorimeter and muon systems have been fully overhauled. The first stage of the all-software trigger is implemented on a GPU farm. The output of the trigger provides a combination of totally reconstructed physics objects, such as tracks and vertices, ready for final analysis, and of entire events which need further offline reprocessing. This scheme required a complete revision of the computing model and rewriting of the experiment's software.
In the initial stage of human life, communication, seen as a process of social interaction, was always the best way to reach consensus between the parties. Understanding and credibility in this process are essential for the mutual agreement to be validated. But, how to do it so that this communication reaches the great mass? This is the main challenge when what is sought is the dissemination of information and its approval. In this context, this study presents the ALT software, developed from original readability metrics adapted to the Portuguese language, available on the web, to reduce communication difficulties. The development of the software was motivated by the theory of communicative action of Habermas, which uses a multidisciplinary style to measure the credibility of the discourse in the communication channels used to build and maintain a safe and healthy relationship with the public. -- No estágio inicial da vida humana a comunicação, vista como um processo de interação social, foi sempre o melhor caminho para o consenso entre as partes. O entendimento e a credibilidade nesse processo são fundamentais para que o acordo mútuo seja validado. Mas, como fazê-lo de forma que e
This work explores the use of Role Playing Games (RPG) as an active methodology in teaching Modern Physics, focusing on a game called Newton's Revenge. The game was developed with the aim of engaging students in collaborative and investigative learning processes, using gamification elements to increase motivation and involvement. Based on the constructivist theories of Piaget and Vygotsky, the RPG stimu- ewline lates cognitive and social development by placing students in the roles of historical science figures. Through contextualized physical challenges, such as understanding the Photoelectric Effect, participants actively construct knowledge. This study presents preliminary learning data obtained through pre- and post-tests, as well as evaluates students' perceptions of using educational games in science education. The results indicate that the use of RPG can be an effective tool for teaching Modern Physics, promoting greater engagement and understanding of scientific concepts.
Linguistic ambiguity continues to represent a significant challenge for natural language processing (NLP) systems, notwithstanding the advancements in architectures such as Transformers and BERT. Inspired by the recent success of instructional models like ChatGPT and Gemini (In 2023, the artificial intelligence was called Bard.), this study aims to analyze and discuss linguistic ambiguity within these models, focusing on three types prevalent in Brazilian Portuguese: semantic, syntactic, and lexical ambiguity. We create a corpus comprising 120 sentences, both ambiguous and unambiguous, for classification, explanation, and disambiguation. The models capability to generate ambiguous sentences was also explored by soliciting sets of sentences for each type of ambiguity. The results underwent qualitative analysis, drawing on recognized linguistic references, and quantitative assessment based on the accuracy of the responses obtained. It was evidenced that even the most sophisticated models, such as ChatGPT and Gemini, exhibit errors and deficiencies in their responses, with explanations often providing inconsistent. Furthermore, the accuracy peaked at 49.58 percent, indicating the need
An analysis of the $B^{0}\rightarrow K^{*0}(\to K^+ π^-)μ^{+}μ^{-}$ decay is presented using proton-proton collision data collected by the LHCb experiment, corresponding to an integrated luminosity of 8.4 fb$^{-1}$. The full set of $CP$-averaged and $CP$-asymmetric angular observables is determined in bins of the invariant mass squared of the dimuon system, as well as the branching fraction relative to the $B^{0}\rightarrow J/ψ(\toμ^{+}μ^{-})K^+π^-$ decay. For the first time, the full set of observables pertaining to the $K^+π^-$ S-wave contribution to the final state are presented and consideration is given to effects arising from the mass of the muons. The measurements of the $CP$-averaged observables and the branching fractions continue to exhibit the pattern of tensions with the Standard Model predictions that have been seen in previous analyses that use part of the dataset considered in this study. The extracted $CP$-asymmetry observables show no significant deviations from zero.
Two semisimple algebraic groups are said to be motivic equivalent if the motives of the associated twisted flag varieties are isomorphic modulo any prime p. The purpose of this note is to construct the combinatorial invariants which characterize motivic equivalence and which are the motivic analogues of the Tits indices which appear in the classification of semisimple algebraic groups. The expression of these invariants -the Tits p-indexes- in terms of the classical invariants associated to the natural underlying structures of semisimple algebraic groups allow to produce algebraic criteria of motivic equivalence, generalizing Vishik's criterion of motivic equivalence for the motives of quadrics. It also clarifies the relation between the motives and the rational geometry of twisted flag varieties. Deux groupes semisimples sont dits motiviquement equivalents si les motifs des varietes de drapeaux generalisees associees sont isomorphes modulo tout nombre premier p. L'objet de cette note est de construire les invariants combinatoires qui caracterisent l'equivalence motivique et sont les analogues motiviques des indices de Tits apparaissant dans la classification des groupes algebrique
The first search for the lepton-flavour violating decays $B^+ \to π^+ μ^{\pm} e^{\mp}$ in proton-proton collisions is presented, using data collected by the LHCb experiment between 2011 and 2018, corresponding to an integrated luminosity of 9 fb$^{-1}$. No significant signal is observed and an upper limit on the branching fraction is set at $\mathcal{B}(B^+ \to π^+ μ^{\pm} e^{\mp}) < 1.8 \times 10^{-9}$ at the $90\%$ confidence level, two orders of magnitude more restrictive than the current world average. This is the first constraint on lepton-flavour violating $b \to d$ quark transitions at the LHC and also sets the most stringent upper limits to date on $b \to d μ^{\pm} e^{\mp}$ transitions. Limits on left-handed and scalar scenarios beyond the Standard Model are also reported.
A search for violation of the charge-parity $C\!P$ symmetry in the $D^+\rightarrow K^-K^+π^+$ decay is presented, with proton-proton collision data corresponding to an integrated luminosity of 5.4 fb$^{-1}$, collected at a center-of-mass energy of $13$ TeV with the LHCb detector. A novel model-independent technique is used to compare the $D^+$ and $D^-$ phase-space distributions, with instrumental asymmetries subtracted using the $D^+_{s}\rightarrow K^-K^+π^+$ decay as a control channel. The $p$-value for the hypothesis of $C\!P$ conservation is $8.1\%$. The $C\!P$ asymmetry observables $A_{C\!P|S}^{φπ^+} = (0.95 \pm 0.43_{stat} \pm 0.26_{syst})\times 10^{-3}$ and $A_{C\!P|S}^{\overline{K}^{*0}K^+} = (-0.26 \pm 0.56_{ stat} \pm 0.18_{syst})\times 10^{-3}$ are also measured. These results show no evidence of $C\!P$ violation and represent the most sensitive search performed through the phase space of a multibody decay.
The methodology for measuring financial assets in defined contribution (DC) pension plans has significant implications whether wealth transfers will occur among participants. In December 2024, a regulatory act was issued for Closed Pension Entities, allowing the use of the hold-to-maturity (HTM) measurement method of treasury bonds in DC plans. This article quantifies the financial impact on participants of adopting HTM valuation in these plans, using real data from the term structure of the real interest rates to assess the resulting wealth transfers. The analysis highlights how HTM valuation creates asymmetries in financial outcomes, benefiting some participants at the expense of others. Wealth transfers occur both during any withdrawal of funds and at the time of contributions, including portfolio reallocations that involve buying or selling bonds. Partial use of HTM or attempts to immunize outflows do not completely eliminate wealth transfers. The results reinforce that the use of mark-to-market (MTM) valuation of assets in DC plans prevents wealth transfers and, consequently, financial losses for participants. O método de mensuração de ativos financeiros em planos de previdênc