Insper

Background: The piezoelectric saw is a technology used in osteotomies, providing precise and minimally invasive cuts, especially in areas close to vital structures. Despite its advantages, limitations such as prolonged surgical time and restrictions in use for larger bones have motivated the development of ultrasonic tips with more efficient geometries. Methods: A laboratory trial was conducted with 40 ultrasonic tips (n = 40), divided into 2 groups: the test group (n = 20), with an ultrasonic tip featuring a multidirectional angular cutting-tooth geometry, and the control (n = 20), with a straight-tooth ultrasonic tip. Two operators performed standardized osteotomies on synthetic bone blocks, with monitoring of variables including cutting time (in seconds), maximum block and blade temperature (in °C), and bone mass loss (in grams). Sample randomization was block-based, and blade coding ensured operator and evaluator blinding. Results: The results showed a statistically significant reduction of approximately 26% in cutting time with the multidirectional ultrasonic tips (Test = 52.85 s; Control = 71.55 s; p < 0.001), regardless of the operator. No significant differences were observed between groups regarding maximum bone temperature (Test = 30.45 °C; Control = 29.40 °C; p = 0.337), blade temperature variation (Test = 5.30 °C; Control = 4.10 °C; p = 0.337), overall temperature variation (Test = -0.19 °C; Control = 0.06 °C; p = 0.285), or bone mass loss (Test = 0.1355 g; Control = 0.0350 g; p = 0.387). A significant interaction between operator and blade type in some variables, such as bone temperature variation (p = 0.001), reinforces the influence of technical experience on the results. Conclusions: The multidirectional angular geometry of the ultrasonic tip significantly improves cutting efficiency without compromising thermal safety, representing a promising advancement for optimizing osteotomies in surgical settings. The use of this new geometry may enhance productivity, particularly in complex procedures, and deserves future clinical investigation to expand its applicability across different surgical specialties, including orthopedics.

ABSTRACT Although cohort studies are essential for understanding health outcomes over time, they often face challenges in participant retention, particularly in contexts of social vulnerability. The return of results to participants has emerged as an ethical and methodological strategy capable of strengthening the bond with participants and reducing loss to follow-up. This article presents the experience of the birth cohort conducted by the Brazilian Center for Early Child Development (CPAPI), in which a Satisfaction Questionnaire was administered to mothers participating in the six-month follow-up stage. The findings identify individual feedback as the primary motivating factor for participants to remain in the study. However, standardized guidelines for institutionalizing this practice are still lacking. We argue that the return of results, beyond being an ethical commitment established in regulatory frameworks, can serve as an effective tool for participant retention in longitudinal studies. Thus, it contributes to the quality and legitimacy of scientific production.

This paper offers a systematic survey of the Brazilian legal scholarship to examine how the duty of care has evolved across different legal fields and to illuminate how these developments can inform current debates on platform regulation and the enforcement of the Brazilian Supreme (STF) Court ruling on intermediary liability. The analysis of the duty of care across various areas of Brazilian law reveals its central role as a principle and often the basis for liability. Essentially, the duty of care imposes a diligent, attentive, and preventive conduct, aiming to avoid damages (as obligations of means), but also serves as the basis for the obligation not to cause harm (as obligations of result). When the duty of care is expressed by an obligation of means, what is required from the agent is the adoption of specific conduct: the application of their best efforts, knowledge, and techniques to achieve a desired goal, without, however, guaranteeing the final outcome. By contrast, where the duty crystallizes as an obligation of result, the legal focus is on the non-occurrence of a specified harm: responsibility is triggered by the materialization of the adverse outcome, independently of the actor’s intent or the efforts undertaken. The STF as the Court recognized a preventive duty of care and identified a series of procedural obligations for digital platforms, yet it did so within a framework that allows those preventive duties to generate liability when serious harm occurs. As Brazilian doctrine already integrates preventive and compensatory logics, it becomes clear the hybrid nature of the STF’s decision and situates it within a broader legal tradition.

In the present work, we consider variable selection and shrinkage for the Gaussian dynamic linear regression within a Bayesian framework. In particular, we propose a novel method that allows for time-varying sparsity, based on an extension of spike-and-slab priors for dynamic models. This is done by assigning appropriate Markov switching priors for the time-varying coefficients’ variances, extending the previous work of (The Annals of Statistics 33 (2005) 730–773). Furthermore, we investigate different priors, including the common Inverted gamma prior for the process variances, and other mixture prior distributions such as Gamma priors for both the spike and the slab, which leads to a mixture of Normal-Gamma priors (Bayesian Analysis 5 (2010) 171–188) for the coefficients. In this sense, our prior can be viewed as a dynamic variable selection prior, which induces either smoothness (through the slab) or shrinkage towards zero (through the spike) at each time point. The MCMC method used for posterior computation uses Markov latent variables that can assume binary regimes at each time point to generate the coefficients’ variances. In that way, our model is a dynamic mixture model; thus, we could use the algorithm of (Journal of the American Statistical Association 95 (2000) 819–828) to generate the latent processes without conditioning on the states. Finally, our approach is exemplified through simulated examples and a real data application.

Convergence in healthcare is integrating information technology (IT) systems with operational technology (OT) systems to improve patient care and operational efficiency. This integration allows for real-time data exchange between medical devices, enhances data analysis for better patient outcomes, and streamlines workflows for healthcare professionals. While the increased networked connectivity of medical devices offers numerous benefits, it also introduces significant cybersecurity threats. We survey and characterize medical devices and then perform a small number of empirical experiments to investigate advertised commercial claims about exposed medical devices unprotected on the Internet. In the first non-commercial, peer-reviewed research paper on this important topic, we validate previous claims and state clearly that a significant problem exists. We conclude that the unique new threats created by IT/OT convergence represent threats to healthcare as a national infrastructure that cannot be solved solely by established IT cybersecurity best practice techniques.