We study partially hyperbolic homoclinic classes of $C^1$-generic diffeomorphisms with a one-dimensional central bundle, so that the central Lyapunov exponent $χ^c(μ)$ is well defined for any ergodic measure $μ$ supported on the class. We focus on nonhyperbolic homoclinic classes supporting ergodic measures with positive, zero, and negative central exponents. For each $α$ and a nontrivial homoclinic class $H$ of a $C^1$-generic diffeomorphism $f$, we consider the level set of measures \[ \mathcal{M}^α_{\mathrm{erg}}(f,H)= \left\{\text{$μ$ ergodic, supported on $H$, with } χ^c(μ)=α\right\}. \] In this generic setting, the range of $α$ for which $\mathcal{M}^α_{\mathrm{erg}}(f,H)$ is nonempty forms a nontrivial closed interval $I$. Since the set of periodic measures is countable, most of these sets contain no periodic measures. We show that for every $α$ in the interior of $I$, the so-called Axiomatized GIKN measures, a class of low-complexity, zero-entropy measures, are dense in $\mathcal{M}^α_{\mathrm{erg}}(f,H)$. This result can be viewed as an analogue of Sigmund's classical density of periodic measures for systems with the specification property, obtained here in a setting where the specification property does not hold and periodic measures are typically absent (in the considered level sets). We also present a similar result for the open class of blender-minimal diffeomorphisms, contained in the class of $C^1$-robustly transitive ones.
This study presents a hierarchical forecasting framework for air traffic in Brazil, leveraging data provided by the National Civil Aviation Agency (ANAC). The framework integrates hierarchical representations of Brazilian air traffic with base forecasting models, such as ETS and SARIMA, and employs classical, as well as state-of-the-art optimal reconciliation techniques to enhance the accuracy of air traffic demand forecasts. Our results demonstrate that forecast reconciliation strategies can substantially improve the reliability of air traffic demand forecasts, thereby supporting more effective resource allocation, infrastructure planning, and tourism management. Our findings further show that classical reconciliation strategies, specifically bottom-up and top-down approaches – in case of the latter particularly Gross–Sohl Method F (TDGSF) – consistently provide strong performance across hierarchical levels. Rather than favoring more complex methods, the results emphasize the importance of aligning reconciliation strategies with data structure and volatility. Finally, our findings highlight the potential of hierarchical forecasting to capture the complex dynamics of Brazil’s air travel market, leading to better decision-making and strategic planning.
(1) To compare sociodemographic characteristics, psychopathology, and substance use patterns among women diagnosed with substance use disorder (SUD) who experienced physical abuse (PA), sexual abuse (SA), or both (PSA); (2) to describe ages of onset; (3) to evaluate the impact of PA, SA, and their interaction on clinical outcomes. Observational retrospective study with patients from PROMUD (Drug Dependent Women Treatment Center) in Brazil. Questionnaires at admission assessed sociodemographics, history of SA and PA, substance use, and psychopathology. t-tests and chi-squared tests were used for descriptive statistics. Logistic and linear regressions estimated associations between clinical outcomes and history of SA or PA in crude and adjusted models. The PA–SA interaction was tested. 401 patients were included (1999–2024). Both SA and PA were associated with greater socioeconomic vulnerability and higher non-heterosexual orientation. SA often began in early childhood, PA more often in adolescence. PA was associated with higher odds of cocaine/crack as the main substance of dependence (OR = 2.7, p < 0.001) and lifetime physical aggression (OR = 1.9, p = 0.018). SA was linked to lifetime suicidal ideation (OR = 2.8, p < 0.01) and use of other substances (OR = 2.0, p = 0.041). No significant PA*SA interaction was found. SA was associated with internalizing patterns, such as suicidal ideation and cannabis/sedative use, whereas PA was linked to externalizing patterns, including physical aggression and cocaine/crack use. These effects were independent, underscoring the need to assess both in women with SUD and to develop gender-sensitive, trauma-informed interventions, particularly where resources are limited.
Plastic waste presents a critical environmental challenge but offers significant potential as a carbon-rich feedstock for valuable products. Pyrolysis, especially of high-density polyethylene (HDPE), has emerged as a promising technology to convert plastic waste into pyrolytic oil, gases, and recoverable monomers, supporting sustainable waste management and energy security across various economies. This study examines the technical and economic feasibility of HDPE pyrolysis at a pilot scale, with a focus on Colombia’s emerging waste management infrastructure. Laboratory experiments optimized key process parameters, including temperature, heating rate, and residence time, while Aspen Plus simulations provided essential insights into mass balance and energy efficiency. Results showed that pyrolysis at 550 °C yielded the highest liquid fraction (71.04
This paper presents the modal analysis of a simple electromechanical system composed of two interacting subsystems, one mechanical and one electromagnetic, and shows how its dynamics differs fundamentally from that of purely mechanical systems. Classical mechanical oscillators exhibit motion governed by the exchange between kinetic and potential energies, whereas the system analyzed here oscillates solely through the exchange between mechanical kinetic and magnetic kinetic energies, since no elements store mechanical or electrical potential energy. Its governing equations involve only two matrices, M and G. Although traditionally referred as inertia and gyroscopic matrices, their physical meaning in this electromechanical context differs substantially: M incorporates both mechanical and electromagnetic inertial contributions, and G does not act as a conventional gyroscopic matrix but instead couples the subsystems and their energy exchange. To the best of our knowledge, this is the first modal analysis of a system composed solely of inertia and gyroscopic matrices. The computed natural frequencies and modes are intrinsically hybrid, involving both mechanical and electromagnetic variables. Hybrid modal coordinates are introduced, and resonance characteristics and frequency response functions are examined. An energetic analysis further reveals that the hybrid natural frequency corresponds to the rate at which energy is exchanged between the mechanical and electromagnetic subsystems.
