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A Complete Inference System for Probabilistic Infinite Trace Equivalence
No full textWe present the first sound and complete axiomatization of infinite trace semantics for generative probabilistic transition systems. Our approach is categorical, and we build on recent results on proper functors over convex sets. At the core of our proof is a characterization of infinite traces as the final coalgebra of a functor over convex algebras. Somewhat surprisingly, our axiomatization of infinite trace semantics coincides with that of finite trace semantics, even though the techniques used in the completeness proof are significantly different
Corticosterone and mitochondrial efficiency are associated with changes in DNA oxidative damage during an acute stress response in Leach’s storm-petrels (Hydrobates leucorhous). Journal of Experimental Zoology: A.
No full textChemical looping combustion of low-volatile semi-anthracite coal with Co-based metal oxide: Performances, kinetics, and mechanisms
No full textThe kinetics of Chemical Looping Combustion (CLC) using Co3O4 as an oxygen carrier for low-volatile semi-anthracite coal were studied with the aim of integrating CO2 capture into the combustion process. The effectiveness of varying temperature regimes (800–950 °C) and oxygen carrier ratios (ϕ = 0.5–2.0) on the CLC process was evaluated. The findings indicate a distinct two-stage combustion sequence: initially, the combustion of volatiles with solid Co3O4 occurs between 460 and 650 °C, followed by the combustion of fixed carbon with gas-phase oxygen released from Co3O4 between 750 and 950 °C. Moreover, the activation energy for volatile combustion was found to be 82 kJ/mol, while for fixed carbon combustion during the non-isothermal stage, it ranged from 31 to 140 kJ/mol. During the isothermal stage, the activation energy for fixed carbon combustion was approximately 234 kJ/mol, with a reaction rate constant (k₀) of 3.7 × 108 s⁻1. The kinetics varied from diffusion-controlled reactions at lower temperatures to first-order or phase-boundary-controlled reactions, and then to Avrami-Erofeev modeled kinetics at higher temperatures, influenced by both temperature and oxygen carrier ratios. This pioneering study provides a comprehensive analysis of the multi-stage kinetics of solid fuel CLC, bridging gaps in current knowledge and laying the groundwork for improved design and efficiency of CLC systems for cleaner energy conversion
Evaluation of Physical and Chemical Stability in Liposomes Composed of Mixed Phospholipids
Full text linkLiposomes, spherical vesicles composed of lipid bilayers, are widely used in drug delivery due to their biocompatibility, biodegradability, and ability to interact with biological membranes. Despite these advantages, liposomes remain moderately unstable systems, highly susceptible to environmental stressors such as pH fluctuations, ionic strength variations, temperature changes, and interactions with other components. Addressing both chemical and physical instability is essential for translating liposomal formulations from experimental formulation to viable pharmaceutical products.
This study investigates the physicochemical characteristics of a mixed-phospholipid system in which one lipid is saturated, and the other is unsaturated (DMPC and DOPC respectively). Liposomes are prepared using thin film hydration, freeze–thaw cycling, and extrusion to yield mostly unilamellar vesicles with diameters of approximately 100 nm. Once prepared, liposomes are exposed to accelerated aging at 70 °C, and aliquots are collected at regular intervals for analysis. Chemical stability was evaluated using high-performance liquid chromatography (HPLC) and lipid peroxidation assays, while physical stability was characterized by dynamic and static light scattering (DLS/SLS), UV–Vis transmittance measurements, and cryogenic transmission electron microscopy (cryo-TEM). Results reveal a strong correspondence between chemical and physical degradation, providing evidence that initial physical changes, such as liposome aggregation and fusion, may play an important role in the onset of chemical degradation and highlighting how subsequent molecular breakdown promotes structural disintegration. This study presents these findings and draws conclusions about the role of lipid composition in controlling liposome stability, offering essential insights for future liposome-based drug delivery system design
Predictors of Facultative Siblicide in Black-legged Kittiwake (Rissa tridactyla) Chicks
No full textIn Black-legged kittiwakes (Rissa tridactyla), a seabird species, competition between siblings can arise when more than one chick is present in a nest. The first-hatched chick, known as the “A” chick, frequently establishes dominance over the second-hatched chick, known as the “B” chick. Many different factors can drive the presence and intensity of this competition, including the size discrepancies between chicks, and their physiological state. A likely factor is resource limitation, seen in many instances of sibling competition to be a prominent component because limited food must be allocated between both chicks by parents. In some cases, competition can escalate into siblicide, with the A-chick showing aggression towards and out-competing (killing) the B-chick. Siblicide attempts can manifest in attacks on the B-chick, with the A-chick sometimes forcing the other out of the nest entirely or pecking them to death. Although siblicide is facultative in Black-legged kittiwakes – occurring frequently but not always – the reasons it occurs in some nests but not others remain unclear. To understand why siblicide only occurs in some nests, it is important to investigate how key factors might predict its likelihood. Some of these factors include environmental context, physiology, and the behavior of chicks. Previous research has shown that chick behavior and condition can be linked to the environment in which they live. In this study, chick behavior was observed during one-hour recordings from 50 nests when the A-chick was 5 days old. These behaviors were quantified to determine the frequency of specific behaviors that could potentially indicate siblicide. While the discrepancy between the A-chick and B-chick in the proportion of begging events that successfully elicited feeding by parents (“successful begging”) was the most reliable predictor of siblicide out of all behaviors observed, none of the behaviors showed a significant ability to predict siblicide overall. Ketones, which can indicate the body condition, of both A-chicks and B-chicks were measured from blood samples after the videos were recorded. Additionally, measurements of the chicks were taken at this time. Both these assessments allowed for the determination of chick quality and condition at this time, to test if this could indicate the chance of siblicide occurring. Among all the physiological factors, the mass of the B-chick showed the most significant ability to predict the occurrence of siblicide, with lighter chicks more likely to die. Another influence on chick survival could be resource availability. Of the 50 nests examined, 24 were provided 3 times daily with supplementary food, and 26 were not provided with any additional food. Feeding treatment played a marginally non-significant role in its interaction with key predictors of siblicide, particularly the mass of the B-chick. More pronounced effects were observed in the unfed group, where the differences in B chick mass between nests with and without siblicide were amplified. This study provides valuable insights into what factors are at play when siblicide occurs in black-legged kittiwake nests. This highlights the importance of B-chick mass as a predictor and how this can be exacerbated by resource limitation. These results contribute to a deeper understanding of the environmental and biological factors that drive siblicide and underscore the significance of early chick conditions in determining survival outcomes
Distracted But Still Listening: How Cognitive and Perceptual Load Affect Multisensory Integration
No full textThere is an ongoing debate about whether multisensory integration (MSI) occurs automatically and before attention is allocated or if multisensory integration occurs after attention is allocated and is subject to top-down attentional control. A recent study investigated this by manipulating the availability of attentional resources in a dual-task paradigm, finding that when the demands of the secondary task increased, susceptibility to the Sound-Induced-Flash-Illusion, a non-speech audiovisual illusion, also increased (Michail & Keil, 2018). This was taken as evidence for the role of post-attentive, top-down control during MSI. In the present study, we extend this logic to explore the role of attentional processes in audiovisual speech integration. Participants completed an audio and audiovisual speech-in-noise task at a fixed signal-to-noise ratio interleaved with an n-back task (0, 1, or 2) to apply cognitive load. We found that as cognitive load increased, speech recognition accuracy decreased in audio and audiovisual stimuli; however, there was no effect of cognitive load on audiovisual enhancement. One limitation of this first experiment was that it did not investigate whether an effect of cognitive load would only be observed under low perceptual load conditions. To address this question, we conducted a follow-up experiment with our dual-task paradigm that manipulated cognitive load via an n-back task and perceptual load via the signal-to-noise ratio of our speech stimuli. We found that there was no interaction between cognitive load, perceptual load, and speech modality, suggesting that cognitive load has no effect on integration regardless of perceptual load. Contrasting prior findings, our results suggest that audiovisual integration of speech occurs in an automatic, pre-attentive manner. Our results underscore the importance of using ecologically valid stimuli in assessing how integration occurs
The Boston METCO Program: Recent Alumni Experiences and Educational Equity
No full textThis project focuses on contemporary school integration practices by examining, in particular, the Boston METCO (Metropolitan Council for Educational Opportunity Inc) program and the experiences of its recent alumni. The METCO program, the United States’ longest-running voluntary school desegregation program, was created in 1966 to give students of color from the city of Boston better educational opportunities by busing them to the surrounding suburbs for school. To this day, it is a program meant to expand educational opportunities, increase diversity, and reduce racial isolation, by permitting students from Boston to attend public schools beyond district lines, in the suburbs. My work focuses on recent graduates and examines the impact METCO had on their lives–it is thus an investigation on the ways in which diversity and inclusion initiatives manifest in the lived experiences of the participants. With a qualitative inquiry approach, the study includes bibliographic research on school integration initiatives, racial discrimination in Boston schools, and documentary analysis of the METCO program’s self-presentation, followed by interviewing recent METCO alumni through in-depth, semi-structured interviews. The study shows the varied impact the program had on students’ daily lives, their relationships with teachers and the challenges to their sense of belonging. The findings also suggest institutional dimensions about education equity and inclusion, raising questions not only about busing as a form of contemporary integration, but also about the future of schools\u27 equitable programs and the improvements they need to ensure all students are feeling connected. Such integrative practices and their effect on the students they are meant to serve prompt us to reconsider equity frameworks in K-12 contexts