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Heat penetration in reactive porous beds
No full textThis study investigates how the ignition method, diffusion-, and convection-driven influences heat penetration in a reactive porous bed of coconut-shell charcoal. A series of 28 controlled experiments was conducted under both diffusion- and convection-driven combustion modes, varying ignition protocols and thermocouple depths within a custom-designed combustion cell. The temperature evolution was measured to delineate heat penetration zones, including water condensation, preheating, and chemical reaction fronts. Results reveal that in assisted ignition, continuous external heating sustains combustion and deepens heat penetration by maintaining high-temperature gradients. In contrast, non-assisted ignition, which relies solely on internal heat release, exhibits faster cooling and limited penetration due to early heat loss and extinction risk. Heat maps constructed from the data show broader preheating zones under diffusion conditions and more pronounced condensation layers under convection. These findings highlight the critical role of ignition conditions in modulating thermal gradients and sustaining smoldering fronts, with implications for fire safety, waste-to-energy systems, and porous media combustion modeling
Birth, life and death of the Devonian Chaitenia back-arc along the Southwestern Gondwanan margin (southern Chile)
No full textThe late Paleozoic evolution of SW Gondwana at the current latitudes of 38-40°S involved three different blocks (Chilenia, Chaitenia and North Patagonia), whose origin and tectonic evolution is debated, making paleogeographic reconstructions challenging. Here we address this issue by constraining the tectonic setting and the metamorphic evolution of mafic rocks outcropping in three sectors (Guzmán at 38°33′S, San Carlos at 40°54′S, Los Pabilos at 40°57′S) of the late Paleozoic basal accretionary complex of the Chilean Coastal Cordillera. The geochemical results suggest that their protoliths originated in a back-arc lithosphere correlating with the Chaitenia back-arc while our P–T–t paths reconstructions show that this basin closed diachronically. In the southern part of the basin, the peak metamorphic conditions of ∼ 450 °C and 1.4–1.6 GPa estimated for the San Carlos blueschists are interpreted as representing a cold thermal configuration for the subduction already reached at 335 Ma (in situ 40Ar/39Ar on phengite). Comparatively, in its northern part, the Guzmán garnet-bearing amphibolites still followed at the same time a warmer counterclockwise P–T path, interpreted as the initiation of the intra-back-arc subduction, reaching metamorphic peak conditions of ∼ 650 °C and 1–1.2 GPa. The amphibolites further cooled down to 500 °C at 311–299 Ma (in situ 40Ar/39Ar on hornblende) and underwent a hydration event under conditions of 480–520 °C and 0.8–1.1 GPa at 277–270 Ma (in situ 40Ar/39Ar on actinolite). Our results suggest that the Chaitenia oceanic arc and back-arc system extended about 300 km further north than previously thought, up to the present 38°S latitude. Moreover, we propose that the opening of the Chaitenia back-arc is closely linked to along-strike transition from collision of the Chilenia terrane at the northwest to normal subduction beneath the North Patagonian margin at the southeast, triggering slab curving, tearing and roll-back
Why Read Beauvoir today?
No full textIn this accessible, personal yet rigorous study, Cristina Chimisso examines Simone de Beauvoir’s philosophy across her oeuvre and locates it within the context of current concerns. Her key ideas are discussed, notably freedom and self-creation, with special attention to their constraints and limitations. Her mature view of other people as freedoms necessary to one’s existence is brought into focus, along with solidarity and communal action. The most important aspects of her feminist philosophy are debated, from the existential consequences of typically female roles, such as wife and mother, to ways in which women misleadingly attempt to make their lives meaningful by depending on other people, or by attending to their own self-image. Chimisso argues that Beauvoir’s analysis of narcissism has acquired renewed importance with the creation of social media, and so has her discussion of women’s complicity with their oppressor now that some women hold positions of power. Her attention to the body is shown to be philosophically rich and capable of stimulating any number of debates, from her rather controversial view of female biology to her phenomenology of old, sick, and dying bodies
University Students' Coping Strategies to Manage Stress: A Scoping Review
No full textThe purpose of this scoping review was to explore what is known about how university students cope with stress. Understanding the coping strategies that students use during university study can improve higher education institutions’ stress reduction/preventative intervention design particularly for students who are struggling. We reviewed 165 international peer-reviewed papers published in English between 2007 and 2022 and extracted information on country of study, design, characteristics of the sample, stressors studied and coping strategies. We found that research on students coping with stress is disproportionately focused on clinical/health-related disciplines and in particular geographical contexts (Asia and Northern America). Study authors used a multitude of conceptualisations and measurements of coping that represent important barriers to generalising findings and implementing actions based on the research evidence. We propose that the development of student-informed measures of coping and their perceptions of coping effectiveness represent possible solutions going forward
Conceptualizing and measuring violence: A feminist critical measurement analysis of gender-based violence research in a government policy-based setting
No full textFeminist methodological advances in gender-based violence research have yet to be comprehensively integrated into policy-based research. This article discusses methodological concerns identified when reviewing the UK government’s public consultation for its 2021 Tackling Violence Against Women and Girls Strategy. We apply intersectional feminist perspectives and critical measurement analysis, and discuss two areas of methodological concern: Issues with conceptualisations of violence, and issues with the measurement of public experiences, attitudes, and opinions, and implications for the accuracy of the survey. In response, we consider feminist research practices that could address these issues and support feminist goals in policy-based gendered violence research
Geometric constructions for Ramsey-Turán theory
No full textCombining two classical notions in extremal combinatorics, the study of Ramsey-Turán
theory seeks to determine, for integers m ≤ n and p ≤ q, the number RTp(n, Kq, m) which is the maximum size of an n-vertex Kq-free graph in which every set of at least m vertices contains a Kp.
Two major open problems in this area from the 80s ask: (1) whether the asymptotic extremal structure for the general case exhibits certain periodic behaviour, resembling that of the special case when p=2; (2) constructing analogues of Bollobás-Erdős graphs with densities other than 1/2.
We refute the first conjecture by witnessing asymptotic extremal structures that are drastically different from the p=2 case, and address the second problem by constructing Bollobás-Erdős-type graphs using high dimensional complex spheres with all rational densities. Some matching upper bounds are also provided
A two‐step formula constant optimization strategy for minimal standard deviation and zero mean prediction error in IOL power calculation
Get PDFPurpose:
To investigate the precision and accuracy performance of a two‐step approach for optimizing lens formula constants (FC) with a refractive offset correction (RO) as a second tuning parameter.
Methods:
Using IOLMaster 700 biometric data from 4 datasets (886/613/821/467 eyes treated with the Hoya Vivinex/Johnson&Johnson ZCB00/Alcon SA60AT/Bausch&Lomb MX60 lens), and the power of the implanted lens and postoperative spherical equivalent refraction, FC and RO were optimized for SRKT, Hoffer Q, Holladay 1, and Haigis formulae using an iterative nonlinear optimization for RMSPE and sequentially according to Gatinel, optimizing first FC for standard deviation prediction error (SDPE) and then RO by the resulting mean prediction error.
Results:
The simple two‐step approach yielded comparable results for the FC and RO for all four formulae and datasets under test. The differences in the formula prediction error were commonly in the third decimals comparing both optimization strategies without clinical relevance. Direct optimization of the FC for SDPE showed large offsets in the formula constant for all datasets and especially for the Hoffer Q and Haigis formulae, resulting in systematic refractive offset values in the formula prediction.
Conclusions:
This simple two‐step approach using FC with a second tuning parameter performs excellently for the four formulae and four datasets under test and allows for both reducing the scatter and zeroing the refractive offset. Multicentric studies with other populations and biometers are required to further investigate the clinical applicability
Large language models for scholarly ontology generation: An extensive analysis in the engineering field
Get PDFOntologies of research topics are crucial for structuring scientific knowledge, enabling scientists to navigate vast amounts of research, and forming the backbone of intelligent systems such as search engines and recommendation systems. However, manual creation of these ontologies is expensive, slow, and often results in outdated and overly general representations. As a solution, researchers have been investigating ways to automate or semi-automate the process of generating these ontologies. One of the key challenges in this domain is accurately assessing the semantic relationships between pairs of research topics. This paper presents an analysis of the capabilities of large language models (LLMs) in identifying such relationships, with a specific focus on the field of engineering. To this end, we introduce a novel benchmark based on the IEEE Thesaurus for evaluating the task of identifying three types of semantic relations between pairs of topics: broader, narrower, and same-as. Our study evaluates the performance of seventeen LLMs, which differ in scale, accessibility (open vs. proprietary), and model type (full vs. quantised), while also assessing four zero-shot reasoning strategies. Several models with varying architectures and sizes have achieved excellent results on this task, including Mixtral-8x 7B, Dolphin-Mistral-7B, and Claude 3 Sonnet, with F1-scores of 0.847, 0.920, and 0.967, respectively. Furthermore, our findings demonstrate that smaller, quantised models, when optimised through prompt engineering, can achieve strong performance while requiring very limited computational resources
‘Please Continue’: Implicit Communication and the Experimenter's Interventions in Stanley Milgram's Obedience to Authority Series
No full textStanley Milgram's ‘Obedience to Authority’ study demonstrated that an experimenter can lead participants to obey orders that seemingly causes others harm. To examine the nature of the experimenter's influence, we analysed the experimenter's non‐procedural interventions in 136 sessions, across four experimental conditions. Results showed that, with a sole exception, Milgram's experimenter used each of his non‐procedural interventions in less than half of both fully obedient sessions and the obedient phases of disobedient sessions. In stark contrast, the intervention ‘Please continue’ was used in virtually all obedient sessions as well as the obedient phases of disobedient sessions, and with substantial frequency. Indeed, results also demonstrated that had Milgram defined a session ‘disobedient’ when any standard prod other than ‘Please continue’ is required, the obedience rates obtained would have already been historic. These findings challenge both the neglect of the experimenter's interactional involvement in Milgram's original account and the focus on explicit acts of argumentation, manipulation, order or the forging of common identity in more contemporary research. Instead, the findings are congruent with the hypothesis that the experimenter operated implicitly, via minimal interpersonal gestures. The paper ends by discussing the claim that, belying their minimal content, these gestures may have contributed to obedience by symbolically deleting participants as active agents, and hence, coercing them