Mapping dynamical heterogeneity in structural glasses to correlated fluctuations of the time variables

Dynamical heterogeneities -- strong fluctuations near the glass transition -- are believed to be crucial to explain much of the glass transition phenomenology. One possible hypothesis for their origin is that they emerge from soft (Goldstone) modes associated with a broken continuous symmetry under time reparametrizations. To test this hypothesis, we use numerical simulation data from four glass-forming models to construct coarse grained observables that probe the dynamical heterogeneity, and decompose the fluctuations of these observables into two transverse components associated with the postulated time-fluctuation soft modes and a longitudinal component unrelated to them. We find that as temperature is lowered and timescales are increased, the time reparametrization fluctuations become increasingly dominant, and that their correlation volumes grow together with the correlation volumes of the dynamical heterogeneities, while the correlation volumes for longitudinal fluctuations remain small.Comment: v4: Detailed analysis of transverse and longitudinal parts. One figure removed, two added. v3: Explicit decomposition into transverse and longitudinal parts, discussion of correlation volumes. One more figure v2: Modified introduction and forma

Slow and Long-ranged Dynamical Heterogeneities in Dissipative Fluids

A two-dimensional bidisperse granular fluid is shown to exhibit pronounced long-ranged dynamical heterogeneities as dynamical arrest is approached. Here we focus on the most direct approach to study these heterogeneities: we identify clusters of slow particles and determine their size, $N_c$, and their radius of gyration, $R_G$. We show that $N_c\propto R_G^{d_f}$, providing direct evidence that the most immobile particles arrange in fractal objects with a fractal dimension, $d_f$, that is observed to increase with packing fraction $\phi$. The cluster size distribution obeys scaling, approaching an algebraic decay in the limit of structural arrest, i.e., $\phi\to\phi_c$. Alternatively, dynamical heterogeneities are analyzed via the four-point structure factor $S_4(q,t)$ and the dynamical susceptibility $\chi_4(t)$. $S_4(q,t)$ is shown to obey scaling in the full range of packing fractions, $0.6\leq\phi\leq 0.805$, and to become increasingly long-ranged as $\phi\to\phi_c$. Finite size scaling of $\chi_4(t)$ provides a consistency check for the previously analyzed divergences of $\chi_4(t)\propto (\phi-\phi_c)^{-\gamma_{\chi}}$ and the correlation length $\xi\propto (\phi-\phi_c)^{-\gamma_{\xi}}$. We check the robustness of our results with respect to our definition of mobility. The divergences and the scaling for $\phi\to\phi_c$ suggest a non-equilibrium glass transition which seems qualitatively independent of the coefficient of restitution.Comment: 14 pages, 25 figure

Harnessing Large Language Models to Enhance Self-Regulated Learning via Formative Feedback

Effectively supporting students in mastering all facets of self-regulated learning is a central aim of teachers and educational researchers. Prior research could demonstrate that formative feedback is an effective way to support students during self-regulated learning (SRL). However, for formative feedback to be effective, it needs to be tailored to the learners, requiring information about their learning progress. In this work, we introduce LEAP, a novel platform that utilizes advanced large language models (LLMs), such as ChatGPT, to provide formative feedback to students. LEAP empowers teachers with the ability to effectively pre-prompt and assign tasks to the LLM, thereby stimulating students' cognitive and metacognitive processes and promoting self-regulated learning. We demonstrate that a systematic prompt design based on theoretical principles can provide a wide range of types of scaffolds to students, including sense-making, elaboration, self-explanation, partial task-solution scaffolds, as well as metacognitive and motivational scaffolds. In this way, we emphasize the critical importance of synchronizing educational technological advances with empirical research and theoretical frameworks.Comment: 9 pages, 3 Figures, 1 Tabl

Strong Dynamical Heterogeneity and Universal Scaling in Driven Granular Fluids

Large scale simulations of two-dimensional bidisperse granular fluids allow us to determine spatial correlations of slow particles via the four-point structure factor $S_4(q,t)$. Both cases, elastic ($\varepsilon=1$) as well as inelastic ($\varepsilon < 1$) collisions, are studied. As the fluid approaches structural arrest, i.e. for packing fractions in the range $0.6 \le \phi \le 0.805$, scaling is shown to hold: $S_4(q,t)/\chi_4(t)=s(q\xi(t))$. Both the dynamic susceptibility, $\chi_4(\tau_{\alpha})$, as well as the dynamic correlation length, $\xi(\tau_{\alpha})$, evaluated at the $\alpha$ relaxation time, $\tau_{\alpha}$, can be fitted to a power law divergence at a critical packing fraction. The measured $\xi(\tau_{\alpha})$ widely exceeds the largest one previously observed for hard sphere 3d fluids. The number of particles in a slow cluster and the correlation length are related by a robust power law, $\chi_4(\tau_{\alpha}) \approx\xi^{d-p}(\tau_{\alpha})$, with an exponent $d-p\approx 1.6$. This scaling is remarkably independent of $\varepsilon$, even though the strength of the dynamical heterogeneity increases dramatically as $\varepsilon$ grows.Comment: 5 pages, 6 figure

Approach and management of diaphragmatic paralysis in adults

3 years ago, 38-year-old male, with no relevant personal pathological history, began to present exertional dyspnea, gastroesophageal reflux, retrosternal pyrosis, dyspepsia and postprandial abdominal distension after a traffic accident. A study protocol was initiated, where cabinet studies documented elevation of the left hemidiaphragm was documented. A minimally invasive approach was performed with the finding of elevation of the left hemidiaphragm of approximately 8 cm in relation to the contralateral diaphragm without evidence of paraesophageal hernia. Mayo type left diaphragmatic plication was performed with non-absorbable suture (polypropylene 1) without complications. With favorable evolution, he started the oral route 8 hours postoperatively, and was discharged 48 hours after surgery due to clinical improvement and without gastroesophageal reflux. Surgical plication of the affected hemidiaphragm is successful in carefully selected patients with severe symptoms thought to be due to unilateral diaphragmatic paralysis. Studies demonstrate improvement in several parameters, including lung and respiratory muscle function, exercise endurance, blood gas exchange, and possibly dyspnea

Unreflected Acceptance -- Investigating the Negative Consequences of ChatGPT-Assisted Problem Solving in Physics Education

Large language models (LLMs) have recently gained popularity. However, the impact of their general availability through ChatGPT on sensitive areas of everyday life, such as education, remains unclear. Nevertheless, the societal impact on established educational methods is already being experienced by both students and educators. Our work focuses on higher physics education and examines problem solving strategies. In a study, students with a background in physics were assigned to solve physics exercises, with one group having access to an internet search engine (N=12) and the other group being allowed to use ChatGPT (N=27). We evaluated their performance, strategies, and interaction with the provided tools. Our results showed that nearly half of the solutions provided with the support of ChatGPT were mistakenly assumed to be correct by the students, indicating that they overly trusted ChatGPT even in their field of expertise. Likewise, in 42% of cases, students used copy & paste to query ChatGPT -- an approach only used in 4% of search engine queries -- highlighting the stark differences in interaction behavior between the groups and indicating limited reflection when using ChatGPT. In our work, we demonstrated a need to (1) guide students on how to interact with LLMs and (2) create awareness of potential shortcomings for users.Comment: Pre-print currently under revie

“Being able to do whatever you wanna do as a woman is important:” a qualitative exploration of contraception as a frame of reference for HIV prevention with PrEP

Background Use of HIV PrEP (pre-exposure prophylaxis) is a strategic tool in the effort to end the HIV epidemic. 20% of new HIV infections in the US are among cis-gender women, yet they comprise only 5% of all PrEP users. Black women disproportionately bear the burden of new HIV acquisition and accounted for almost 60% of new HIV diagnoses among women in 2018. Increasing understanding and uptake of PrEP among women at risk of HIV acquisition in alignment with their reproductive values and preferences is key to increasing PrEP uptake and decreasing HIV burden in this population. Objective This study examines how experiences with contraception among women of color shape their perceptions and preferences regarding HIV PrEP to inform counseling that aligns with their reproductive values. Methods Women aged 18–45 who self-identified as Black or Latina were recruited at an academic medical center in the Bronx from June 2018 to July 2019. We enrolled 30 participants seeking family planning care (10), prenatal care (10), or care for sexually transmitted infections (10). Participants completed a brief written survey assessing their risk of HIV acquisition. Semi-structured, face-to-face interviews were then audio-recorded, transcribed, and entered into Dedoose. Grounded theory and constant comparison approaches were used to analyze the data. Results Twenty-one participants (70%) screened positive for HIV acquisition risk. Four had received information on PrEP from a medical provider prior to the interview. Three themes emerged from the qualitative analysis: (1) Similar to oral contraception, women conceptualized PrEP as a “daily pill” to support their reproductive health; (2) Women perceived PrEP as a tool to support autonomy and pleasure in their sexual health; (3) Like birth control, women desired multiple delivery options for HIV prophylaxis. Conclusions Contraception may serve as a frame of reference when counseling about PrEP among cis-women at risk of acquiring HIV. Our study suggests that this approach re-contextualizes counseling on PrEP within a sex-positive framework that prioritizes pleasure, safety, and autonomy as integral to sexual and reproductive wellness. Consideration of historically marginalized women’s experiences with contraception and reproductive values may facilitate their use of PrEP