arXiv subjects

Eduardo Moreno-Barbosa

Publications and source records attributed to Eduardo Moreno-Barbosa.

6 recordsLinked to original sources

arXiv2026

Left-lateralized reduced white matter structural connectivity in young women with obesity: analysis of graph theory applied to inter-tract correlation matrices

Objective: Differences in WM structural connectivity were sought by comparing graph measures from young women with normal weight ($D_\mathrm{norm}$) and obesity ($D_\mathrm{over}$), studying FA-based inter-tract correlation matrices. Methods: Undirected binary adjacency matrices were created from WM inter-tract correlation matrices. Sixteen global graph measures were compared between the $D_\mathrm{norm}$ and $D_\mathrm{over}$ groups. At the nodal level, four graph measures were compared. Optimal community structures were calculated using the Louvain community detection algorithm. This was done considering all network, as well as the left and right hemispheres separately. Results: At the global level and considering all network, the $D_\mathrm{over}$ group had significantly reduced global efficiency compared to the $D_\mathrm{norm}$ group. Considering only the right hemisphere, none of the graph measures were significantly different between the two groups. Studying only the left hemisphere, the $D_\mathrm{over}$ group obtained significantly reduced measures compared to the $D_\mathrm{norm}$ group in five global graph measures. At the nodal level, the $D_\mathrm{over}$ group obtained significantly reduced graph measures in WM tracts when studying all network and the left hemisphere separately. These tracts were mainly involved in the reward network. The optimal community structures calculated were consistent with the results reported. Conclusion: The $D_\mathrm{over}$ group showed altered and reduced structural connectivity in WM tracts compared to the $D_\mathrm{norm}$ group. The reported tracts are involved in reward processing, inhibitory control, executive decision-making, and cognitive processing. In addition to obtaining results consistent with those reported in the literature, it was additionally observed that the results were lateralized to the left hemisphere.

physics.med-ph↗

arXiv2025

An Exact Moment-Based Approach for Chemical Reaction-Diffusion Networks: From Mass Action to Hill Functions

Biochemical systems are inherently stochastic, particularly those with small-molecule populations. The spatial distribution of molecules plays a critical role and requires the inclusion of spatial coordinates in their analysis. Stochastic models such as the chemical master equation are commonly used to study these systems. However, analytical solutions are limited to specific cases, and stochastic simulations require significant computational resources. To mitigate these challenges, approximation methods, such as the moment approach, reduce the system to a set of ordinary differential equations, thereby lowering the computational requirements. This study investigates the conditions under which the second-moment approach yields exact results during the dynamic evolution of chemical reaction-diffusion networks. The analysis encompasses second-order or higher-order reactions and Hill functions without relying on higher-order moment estimations or closure approximations. Starting with stationary states, we extended the analysis to a dynamic evolution. An enzymatic process and an antithetic feedback system were examined for purely reactive systems, demonstrating the approach's accuracy in capturing system behavior and quantifying errors. The study was further extended to genetic regulatory networks governed by Hill functions, including both purely reactive and reaction-diffusion systems, validating the method in spatially distributed contexts. This framework enables precise characterization of biochemical systems, avoiding information loss typically associated with approximations and allowing for stability analysis under fluctuations. These findings optimize computational strategies while providing insights into intracellular signaling and regulatory processes, paving the way for efficient and accurate stochastic modeling in biochemical systems.

q-bio.MN↗

arXiv2023

Trigger efficiencies of a proposed beam monitoring detector (BeBe) for p+p collisions at NICA energies

The Multipurpose Detector (MPD) consists of a typical array of sub-detectors to study the nuclear matter originating from the collisions of beams provided by the Nuclotron-based Ion Collider fAcility (NICA). A beam monitoring detector~(BeBe) is proposed for stage 2 of MPD to increase the trigger capabilities. BeBe is constituted of two plastic scintillator disks segmented in 80 cells $\pm~2~m$ away from the interaction point of MPD. Laboratory measurements to obtain the energy resolution of an individual BeBe cell prototype are presented. It is shown that an energy resolution of $22\pm6\%$ can be obtained. Based on Monte Carlo simulations, the trigger efficiencies of the BeBe are presented for p+p collisions at 11~GeV considering a threshold in the energy loss of the charged particles reaching the detector.

hep-ex↗

arXiv2022

Performance of BeBe, a proposed dedicated beam-beam monitoring detector for the MPD-NICA experiment at JINR

The Multipurpose Detector (MPD) is an experimental array, currently under construction, designed to study the nuclear matter created during the collisions that will be provided by the Nuclotron-based Ion Collider fAcility (NICA) at JINR. The MPD-NICA experiment consists of a typical array of particle detectors as those used to study heavy-ion collisions at LHC and RHIC. To increase the trigger capabilities of MPD for stage 2 of NICA operation, a detector conformed by two arrays of 80 plastic scintillator cells each located symmetrically at opposite sides of the interaction point of MPD is proposed (BeBe). Based on Monte Carlo simulations, a discussion of the potential physics performance of BeBe detector is given for triggering tasks and for the resolution in the determination of the event plane reaction and the centrality of the collisions at NICA. Also, laboratory measurements to estimate the time resolution of individual BeBe cells prototypes are presented. It is shown that a time resolution between 0.65 and 1.48 ns can be reached depending on the number of photosensors employed to collect the scintillation photons. The BeBe detector will be complementary to FFD and FHCAL forward detectors.

physics.ins-det↗

arXiv2022

Brain MRI study for glioma segmentation using convolutional neural networks and original post-processing techniques with low computational demand

Gliomas are brain tumors composed of different highly heterogeneous histological subregions. Image analysis techniques to identify relevant tumor substructures have high potential for improving patient diagnosis, treatment and prognosis. However, due to the high heterogeneity of gliomas, the segmentation task is currently a major challenge in the field of medical image analysis. In the present work, the database of the Brain Tumor Segmentation (BraTS) Challenge 2018, composed of multimodal MRI scans of gliomas, was studied. A segmentation methodology based on the design and application of convolutional neural networks (CNNs) combined with original post-processing techniques with low computational demand was proposed. The post-processing techniques were the main responsible for the results obtained in the segmentations. The segmented regions were the whole tumor, the tumor core, and the enhancing tumor core, obtaining averaged Dice coefficients equal to 0.8934, 0.8376, and 0.8113, respectively. These results reached the state of the art in glioma segmentation determined by the winners of the challenge.

eess.IV↗

arXiv2020

The conceptual design of the miniBeBe detector proposed for NICA-MPD

We present the conceptual design for the miniBeBe detector proposed to be installed as a level-0 trigger for the TOF of the NICA-MPD. We discuss the design and the geometrical array of its sensitive parts, the read-out electronics as well as the mechanical support that is envisioned. We also present simulation results for p + p and Bi + Bi collisions to study its capabilities as a function of multiplicity both as a level-0 trigger for the TOF, as well as to serve as a beam-gas interaction veto and to locate the beam-beam interaction vertex.

physics.ins-det↗