Coleção de Artigos Acadêmicos

URI permanente para esta coleçãohttps://repositorio.insper.edu.br/handle/11224/3227

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Agora exibindo 1 - 10 de 156

The credibility of finance committees and information usage: trustworthy to whom?
(2022) Domingos, Fernando Deodato; Aquino, André Carlos Busanelli de; Lima, Diana Vaz de
Analysing municipal councils in Brazil, this article contributes to the understanding of how politiciansuse accounting information in terms of the dynamics of collective political decisions. Depending ontheir political position, the authors investigated whether councillors seek accounting information tocope with varied objectives rather than a uniﬁed decision-making process. A survey of local ﬁnancecommittee members showed that information source credibility is a sensitive construct with multiplemeanings inﬂuenced by the political environment. This article adds to prior literature on the demandand supply sides of information
In-kind Transfers in Brazil: Household Consumption and Welfare Effects
(2021) Palialol, Bruno Toni; Pereda, Paula Carvalho
The Worker Food Program (Programa de Alimentação do Trabalhador - PAT) creates tax incentives for firms to provide more than 20 million Brazilian workers with in-kind transfers. They are usually distortive compared to cash transfers, but this is not clear when the latter, when paid by the employer, are subject to payroll taxes like in Brazil. Using propensity score analysis, we find evidence that the PAT increases poor households’ food consumption between 15.7% and 25.0% compared to cash transfers. This result, however, may not be improving workers’ nutrition, as sought by the program.
An Automated Electronic System in a Motorized Wheelchair for Telemonitoring: Mixed Methods Study Based on Internet of Things
(2023) Gradim, Luma Carolina Câmara; Santana, André Luiz Maciel; José, Marcelo Archanjo; Zuffo, Marcelo Knörich; Lopes, Roseli de Deus
Background: Wheelchair positioning systems can prevent postural deficits and pressure injuries. However, a more effective professional follow-up is needed to assess and monitor positioning according to the specificities and clinical conditions of each user. Objective: This study aims to present the concept of an electronic system embedded in a motorized wheelchair, based on the Internet of Things (IoT), for automated positioning as part of a study on wheelchairs and telemonitoring. Methods: We conducted a mixed methods study with a user-centered design approach, interviews with 16 wheelchair users and 66 professionals for the development of system functions, and a formative assessment of 5 participants with descriptive analysis to design system concepts. Results: We presented a new wheelchair system with hardware and software components developed based on coparticipation with singular components in an IoT architecture. In an IoT solution, the incorporation of sensors from the inertial measurement unit was crucial. These sensors were vital for offering alternative methods to monitor and control the tilt and recline functions of a wheelchair. This monitoring and control could be achieved autonomously through a smartphone app. In addition, this capability addressed the requirements of real users. Conclusions: The technologies presented in this system can benefit telemonitoring and favor real feedback, allowing quality provision of health services to wheelchair users. User-centered development favored development with specific functions to meet the real demands of users. We emphasize the importance of future studies on the correlation between diagnoses and the use of the system in a real environment to help professionals in treatment.
Análise morfológica de nanofibras: uma abordagem por visão computacional e aprendizagem de máquina
(2021) Barros, Guilherme Duarte de; Santana, André Luiz Maciel; Pereira, Vitor Matheus Ferraz; Pereira, Wesley da Silva; Santana, André Luiz Maciel
The studies and applications of nanofibers have grown over the years. It was observed that the properties of the nanometer-scale yarns present advantages in applications in several areas, such as biomedical, energy storage and production, and applications involving water filtration. These materials are synthesized through a technical process and, for that reason, they are subject to the presentation of failures. The most common flaws are the formation of granules and pores. With the evolution of computing, applications that use machine learning resources can assist in detecting these failures. This work aims to evaluate and compare two different approaches to morphological analysis to see losses in nanofibers. Firstly, a data set was created using a Scanning Electron Microscope. After that, each image was analyzed by ImageJ software and by RNA solution. As a hypothesis, the article will assess whether the beads identification and the number of beads by the analog method are statistically similar (H0) or statistically different (H1) from the machine learning method. The preliminary results indicate that for the group that used 100 images and computer visualization, the analog method's accuracy was 7.23%. In order to accuracy increase, another test with 150 more distinct images was done, bringing a new result of 55.09%. The analysis time was considerably less when performed by the computational method. It was possible to conclude that the computational approach does not have the beads identification statistically similar to the analog way concerning the methodology used. Therefore, rejected H0. However, the directly proportional relationship of accuracy with the number of samples suggests that training with more various images can calibrate the algorithm.
Prediction of bacterial and fungal bloodstream infections using machine learning in patients undergoing chemotherapy
(2025) Freire, Maristela P.; ADHEMAR VILLANI JUNIOR; Lazar Neto, Felippe; Lage, Luis Alberto De Padua Covas; Oliveira, Maura Salaroli; Abdala, Edson; Nunes, Fatima L.S.; Levin, Anna Sara S.
Purpose This study aimed to develop a machine learning (ML) model to predict bloodstream infection (BSI) in chemotherapy patients. Patients and methods We included all cancer patients undergoing chemotherapy at a tertiary cancer hospital from 2017 to 2022. Data were collected per chemotherapy cycle, including chemotherapy drugs, indications, cycle number, cancer type, body mass index, age, gender, complete blood count, creatinine levels, and microbial cultures. BSI was assessed within 21 days after chemotherapy. The ML algorithms tested included logistic regression, ridge regression, k-nearest neighbors, Naive Bayes, Perceptron, neural networks, decision trees, boosting methods, Random Forests, and Support Vector Machines. The SHapley Additive exPlanations (SHAP) method was used to measure feature importance. Results Among 107,757 cycles from 19,225 patients, 91.7 % had solid tumors, primarily breast (36.8 %) and gastrointestinal (19.4 %) cancers. The first cycle accounted for 23.7 % of cycles, and palliative chemotherapy made up 52.9 %. Alkylating agent was the most common drug class used (55.5 %). BSI occurred in 1.33 % of cycles, with 34 % of these cases occurring in neutropenic patients. Of the bacteremia cases, 11.8 % were polymicrobial, and 69.3 % involved gram-negative bacteria. The best model was a neural network with one hidden layer (5 neurons), achieving 70.7 % sensitivity, 93.49 % specificity, 93.19 % accuracy, and an area under a receiver operating characteristic curve of 91.93 %. Key predictors included the first cycle, antimetabolite use, palliative chemotherapy, monocytopenia, and hematological malignancies. Conclusion ML effectively predicts bacteremia in chemotherapy patients, including non-neutropenic cases, and could be used in clinical practice to guide treatment and infection workup.
Evaluation of artifacts produced by cannulated and solid-core screws using magnetic resonance imaging and computed tomography
(2026) Cassanego, Guilherme Rech; Rahal, Sheila Canevese; Santos, Tauan Silva Gouveia; Silva, Jeana Pereira da; Santos, Diogo Borges Renó dos; Mamprim, Maria Jaqueline; Carbonari, Marcelo José; Siqueira, Rafael Cerântola
This study aimed to evaluate, using both magnetic resonance imaging (MRI) and computed tomography (CT), the imaging artifacts associated with two types of titanium screws—cannulated and solid—from three different manufacturers, implanted in the canine humeral condyle. Three groups were established: G1 – 3.5 × 30 mm solid cortical screws and partially threaded cannulated screws; G2 – 3.5 × 28 mm solid cortical screws and 3.5 × 26 mm fully threaded conical compression cannulated screws; and G3 – 3.5 × 30 mm solid screws and 3.0 × 26 mm fully threaded conical compression cannulated screws. MRI evaluation was performed using SE DP/T2, Turbo 3D T1, STIR, and fast FLAIR sequences, while CT evaluation used transverse images. On MRI, solid screws produced more discrete and localized artifacts, mainly as peri-implant signal void/blooming with minimal geometric distortion and mild limitation of cortical and articular surface assessment. In contrast, cannulated screws generated larger areas of signal loss, especially in Turbo 3D T1 and fat-suppressed STIR/FLAIR sequences, although humeral condyle evaluation remained feasible. On CT, solid screws exhibited more pronounced metallic artifacts (beam hardening, streaks, mild blooming) compared with cannulated screws; however, these artifacts did not prevent assessment of peri-implant structures. Artifact measurements on MRI (Turbo 3D T1) and CT were higher for cannulated screws in G1 and G2, whereas in G3 solid screw produced greater artifact. In conclusion, both design and material composition of the screw significantly influence image quality, highlighting the importance of considering these factors when selecting the screw and planning imaging protocols.
Who gets the Better Deal in Marriage? Examining Racial Differences in Brazilian Marriage Market
(2025) Duque, Daniel; França, Michael; Mendonca, Milena
This paper studies women’ marriage market in Brazil, investigating socioeconomic disparities and their trends in marriage outcomes. Relying on nationally representative data from the National Household Sample Survey (PNAD) covering 2002 to 2024, we analyze the association between marital status and these variables, as well as patterns of assortative mating by examining the educational and productivity pairing within couples. The results indicate that higher educational attainment among women is associated with a greater likelihood of being married, but, after accounting for education and age, black and mixed-race women continue to exhibit lower marriage rates relative to white counterparts. The analysis also reveals a strong persistence of educational assortment among spouses, but black and mixed-race women have lower quality husbands, even with sociodemographic controls, with non-consistent trends towards more or less inequality. We also show that a similar pattern arises across parental education, with black women from highly educated parents having lower marriage outcomes. Together, these findings advance the understanding of how economic sorting in the marriage market can reinforce broader patterns of racial and educational inequality in Brazil.
Subway expansion, job accessibility improvements, and home value appreciation in four global cities: Considering both local and network effects
(2022) Adriano Borges Costa; ADRIANO BORGES FERREIRA DA COSTA; Ramos, Camila; Zheng, Siqi
We explore the potential of incorporating accessibility analysis in addressing the impact of subway expansions on the real estate market. We first demonstrate that by using increases in accessibility to jobs as a continuous treatment variable, rather than adopting a binary station dummy approach, we achieve better goodness-of-fit in a quasiexperimental econometric analysis. Furthermore, accessibility measures allow the exploration of impacts beyond the local effects around new subway stations, shedding light on a network impact that has been largely overlooked to date. To increase the external validity of our findings, we apply the same analysis to the cities of Santiago (Chile), Sao Paulo (Brazil), Singapore, and Barcelona (Spain). and then explore the emergent patterns. We argue that the integration of urban economics and transportation analysis via the use of accessibility measures constitutes an innovation in the empirical approach commonly adopted in the literature. The use of such measures in causal empirical studies on transportation impacts can yield more robust and comprehensive results and capture nuanced spatial heterogeneity effects.
Exploring the causal effects of the built environment on travel behavior: a unique randomized experiment in Shanghai
(2022) Chen, Faan; ADRIANO BORGES FERREIRA DA COSTA
Experimental designs have been recognized as the gold standard for establishing causal mechanisms. However, the application of such designs is complicated by factors such as excessive costs, time consumption, ethical concerns, and political impossibility. Nevertheless, the Chinese government’s replacement housing efforts provide a unique randomized experiment for exploring the causal effects of the built environment on travel behavior. Accordingly, based on a large-scale survey on travel patterns under an experimental design in Shanghai, this study employs a two-step modeling approach, involving logit and Tobit models, to identify the built environment’s effects on auto ownership and vehicle kilometers traveled (VKT). We found that transit service improvements play a stronger role in reducing auto-drive than compact and diverse land-use characteristics. Increasing residential and employment density, as well as land-use mix, discourages car ownership, which in turn reduces VKT, but with lower elasticities than transportation system variables. The findings provide additional evidence and referential estimate for how land-use and transport strategies and policies designed to create a compact, mixed-use, and highly accessible built environment can be used in reducing auto driving. This study expands the VKT reduction elasticities’ database regarding the built environment across global spatial contexts, serving as a model for similar studies elsewhere in the world.
Analytical definitions of connectivity, incidence and node matrices for t-struts tensegrity prisms
(2024) Paiva, Victor A.S.M.; Kurka, Paulo R.G.; Izuka, Jaime H.
Regular tensegrity prism modules are widely used by researchers. Numerous research articles combine them to form grids and towers under various assembly strategies. Most of them define connectivity and node matrices that satisfy their structures as a whole, but a general definition for the basic modules has not been formally reported. This paper formalizes sets of definitions for the connectivity, incidence, and node matrices that are valid for any tensegrity prism formed by four struts or more. The definitions are based on geometry and provide simple and general formulations by applying floor and ceiling operators. Both clockwise and counterclockwise rotated modules are covered.

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