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Nonlinear biomolecular interactions on membranes drive membrane remodeling crucial for biological processes including chemotaxis, cytokinesis, and endocytosis. The complexity of biomolecular interactions, their redundancy, and the importance of spatiotemporal context in membrane organization impede understanding of the physical principles governing membrane mechanics. Developing a minimal in vitro system that mimics molecular signaling and membrane remodeling while maintaining physiological fidelity poses a major challenge. Inspired by chemotaxis, we reconstructed chemically regulated actin polymerization inside vesicles, guiding membrane self-organization. An external, undirected chemical input induced directed actin polymerization and membrane deformation uncorrelated with upstream biochemical cues, suggesting symmetry breaking. A biophysical model incorporating actin dynamics and membrane mechanics proposes that uneven actin distributions cause nonlinear membrane deformations, consistent with experimental findings. This protocellular system illuminates the interplay between actin dynamics and membrane shape during symmetry breaking, offering insights into chemotaxis and other cell biological processes. 

Abstract Mechanisms have been proposed to enhance the merger rate of stellar-mass black hole binaries, such as the Von Zeipel–Lidov–Kozai mechanism (vZLK). However, high inclinations are required in order to greatly excite the eccentricity and to reduce the merger time through vZLK. Here, we propose a novel pathway through which compact binaries could merge due to eccentricity increase in general, including in a near coplanar configuration. Specifically, a compact binary migrating in an active galactic nucleus disk could be captured in an evection resonance, when the precession rate of the binary equals the orbital period around the supermassive black hole. In our study we include precession due to first-order post-Newtonian precession as well as that due to disk around one or both components of the binary. Eccentricity is excited when the binary sweeps through the resonance, which happens only when it migrates on a timescale 10–100 times the libration timescale of the resonance. Libration timescale decreases as the mass of the disk increases. The eccentricity excitation of the binary can reduce the merger timescale by up to a factor of ∼10 3−5 . 

Mentorship has been established in the literature as being salient to degree completion for doctoral students. Mentoring primarily focuses on the extended academic development of a less experienced student by a more experienced faculty scholar. Federal governance policies have enabled greater participation in STEM by underrepresented populations, and as a result, enrollments in doctoral STEM programs by groups underrepresented in STEM have increased, but their success frequently hinges on support resources such as quality mentorship (Millett & Nettles, 2006). A substantial commitment to high-quality mentoring is needed to best prepare doctoral students for high skilled careers requiring innovation. This paper explores the perceptions of STEM doctoral faculty from three institutions in the southeastern part of the United States to understand their knowledge of STEM doctoral mentoring. This work seeks to improve STEM doctoral education by focusing on the mentorship relationship, an experience that is vital to matriculation, degree completion, and career planning Millett & Nettles, 2006). Using a qualitative multiple embedded case study design, the researchers interviewed and surveyed STEM doctoral faculty about their perceptions of STEM doctoral mentoring. This article focuses on five key findings from the qualitative interviews. STEM doctoral faculty: (a) have difficulty differentiating mentoring responsibilities from and in addition to advising; (b) have limited mentoring training opportunities; (c) see mentoring more exclusively as the development of scientific knowledge; (d) lack meaningful understanding of the role of culture in mentoring; and (e) lack deep understanding of the importance of relational connections with mentees. 

Underrepresented minority (URM) students have not been well represented within the ranks of doctoral degree holders or faculty in STEM disciplines despite the increased attention in recent years to this concern. URM students lag considerably behind White and Asian students in degree completion and faculty appointments. One intervention widely touted as effective in promoting positive outcomes is mentoring however URM students often lack access to mentoring and just as importantly mentors lack culturally responsive knowledge, skills and dispositions required to be effective mentors to URM students. A qualitative study was conducted to better understand how the knowledge, skills and dispositions of STEM faculty align with culturally responsive mentoring. Three themes were constructed from the data: role ambiguity, preparedness, and culture of doing. The study concluded that faculty need more and better training around cultural responsiveness to meet the needs of URM students.