Publications by authors named "Humberto Rocha"

Article Synopsis
  • Radiotherapy treatment planning is shifting towards more automation, similar to the changes seen in the aviation industry, raising concerns about human roles and risks within these automated systems.
  • A working group at the ESTRO Physics Workshop 2023 suggested a framework based on aviation insights, outlining different levels of automation in radiotherapy and their impact on human involvement.
  • Key risks of this automation include complacency and data overload, which necessitate strategies like checklists and proper training to ensure effective human-automation collaboration while maintaining the critical need for human oversight in complex clinical scenarios.*
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The critical temperature beyond which photosynthetic machinery in tropical trees begins to fail averages approximately 46.7 °C (T). However, it remains unclear whether leaf temperatures experienced by tropical vegetation approach this threshold or soon will under climate change.

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Presumably, intensity-modulated proton radiotherapy (IMPT) is the most powerful form of proton radiotherapy. In the current state of the art, IMPT beam configurations (i.e.

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Two methods for non-coplanar beam direction optimization, one for static beams and another for arc trajectories, were proposed for intracranial tumours. The results of the beam angle optimizations were compared with the beam directions used in the clinical plans. Ten meningioma cases already treated were selected for this retrospective planning study.

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Background: Unbiased analysis of the impact of adaptive radiotherapy (ART) is necessary to evaluate dosimetric benefit and optimize clinics' workflows. The aim of the study was to assess the need for adaptive radiotherapy (ART) in head and neck (H&N) cancer patients using an automatic planning tool in a retrospective planning study.

Materials And Methods: Thirty H&N patients treated with adaptive radiotherapy were analysed.

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Article Synopsis
  • - The FLUXNET2015 dataset encompasses ecosystem-scale data on carbon dioxide, water, and energy exchange, collected from 212 global sites contributing over 1500 site-years of data until 2014.
  • - The dataset was systematically quality controlled and processed, facilitating consistency for various applications in ecophysiology, remote sensing, and ecosystem modeling.
  • - For the first time, derived data products such as time series, ecosystem respiration, and photosynthesis estimates are included, and 206 sites are made accessible under a Creative Commons license, with the processing methods available as open-source codes.
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Background: This work aims at clinically validating a graphical tool developed for treatment plan assessment, named SPIDERplan, by comparing the plan choices based on its scoring with the radiation oncologists (RO) clinical preferences.

Methods: SPIDERplan validation was performed for nasopharynx pathology in two steps. In the first step, three ROs from three Portuguese radiotherapy departments were asked to blindly evaluate and rank the dose distributions of twenty pairs of treatment plans.

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Purpose: To compare two beam angle optimization (BAO) algorithms for coplanar and non-coplanar geometries in a multicriterial optimization framework.

Methods: 40 nasopharynx patients were selected for this retrospective planning study. IMRT optimized plans were produced by Erasmus-iCycle multicriterial optimization platform.

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The immune system and tumor microenvironment play a decisive role in tumor progression. We developed a novel model to better understand tumor progression and interaction with immune cells and the cellular components. We grew 393 P non-metastatic and 344SQ metastatic murine cells in an acellular metastatic lung cancer model, where both cell lines formed circulating tumor cells (CTC) and metastatic lesions.

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The choice of areas for nature conservation involves the attempt to maximize the benefits, whether by carrying out an economic activity or by the provision of Ecosystem Services. Studies are needed to improve the understanding of the effect of the extent and position along the watershed of restored areas on soil and water conservation. This study aimed to understand how different restoration strategies might reflect in soil conservation and sediment retention.

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Purpose: The inverse planning of an intensity-modulated radiation therapy (IMRT) treatment requires decisions regarding the angles used for radiation incidence, even when arcs are used. The possibility of improving the quality of treatment plans by an optimized selection of the beam angle incidences-beam angle optimization (BAO)-is seldom done in clinical practice. The inclusion of noncoplanar beam incidences in an automated optimization routine is even more unusual.

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Purpose: The planning of an intensity modulated radiation therapy treatment requires the optimization of the fluence intensities. The fluence map optimization (FMO) is many times based on a nonlinear continuous programming problem, being necessary for the planner to define a priori weights and/or lower bounds that are iteratively changed within a trial-and-error procedure until an acceptable plan is reached. In this work, the authors describe an alternative approach for FMO that releases the human planner from trial-and-error procedures, contributing for the automation of the planning process.

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Electing irradiation directions to use in IMRT treatments is one of the first decisions to make in treatment planning. Beam angle optimization (BAO) is a difficult problem to tackle from the mathematical optimization point of view. It is highly non-convex, and optimization approaches based on gradient descent methods will probably get trapped in one of the many local minima.

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Objective: To correct the misclassification and improve the quality of information on maternal mortality in Mexico.

Materials And Methods: Using clinical records and verbal autopsies, we studied all deaths certified as maternal deaths as well as a selection of deaths of women of childbearing age whose causes were considered as suspected of hiding a maternal death, all of which occurred during 2011 within Mexico.

Results: The deliberate search of maternal deaths and reclassification allowed the rescue of just over 100 deaths that were not originally registered or coded as maternal and confirmed or corrected the causes of death recorded on death certificates as confirmed maternal deaths.

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Generally, the inverse planning of radiation therapy consists mainly of the fluence optimization. The beam angle optimization (BAO) in intensity-modulated radiation therapy (IMRT) consists of selecting appropriate radiation incidence directions and may influence the quality of the IMRT plans, both to enhance better organ sparing and to improve tumor coverage. However, in clinical practice, most of the time, beam directions continue to be manually selected by the treatment planner without objective and rigorous criteria.

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We used eddy covariance and ecological measurements to investigate the effects of reduced impact logging (RIL) on an old-growth Amazonian forest. Logging caused small decreases in gross primary production, leaf production, and latent heat flux, which were roughly proportional to canopy loss, and increases in heterotrophic respiration, tree mortality, and wood production. The net effect of RIL was transient, and treatment effects were barely discernable after only 1 y.

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The effect of Johrei treatment on the crystallization of sucrose from supersaturated solutions was studied in comparison with the crystallization in untreated solutions. This work was performed assuming that Johrei enhances the natural mechanisms of equilibrium restoration in biological and nonbiological systems. The crystallization in Johrei-treated solutions as judged by statistical analysis was found to be faster than the crystallization in untreated solutions.

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Coupled climate-carbon cycle models suggest that Amazon forests are vulnerable to both long- and short-term droughts, but satellite observations showed a large-scale photosynthetic green-up in intact evergreen forests of the Amazon in response to a short, intense drought in 2005. These findings suggest that Amazon forests, although threatened by human-caused deforestation and fire and possibly by more severe long-term droughts, may be more resilient to climate changes than ecosystem models assume.

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In this paper, we review some critical issues regarding carbon cycling in Amazonia, as revealed by several studies conducted in the Large Scale Biosphere Atmosphere Experiment in Amazonia (LBA). We evaluate both the contribution of this magnificent biome for the global net primary productivity/net ecosystem exchange (NPP/NEE) and the feedbacks of climate change on the dynamics of Amazonia. In order to place Amazonia in a global perspective and make the carbon flux obtained through the LBA project comparable with global carbon budgets, we extrapolated NPP/NEE values found by LBA studies to the entire area of the Brazilian Amazon covered by rainforest.

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The net ecosystem exchange of carbon dioxide was measured by eddy covariance methods for 3 years in two old-growth forest sites near Santarém, Brazil. Carbon was lost in the wet season and gained in the dry season, which was opposite to the seasonal cycles of both tree growth and model predictions. The 3-year average carbon loss was 1.

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