Boston College

Bistable switching typically arises from ferroic orders, such as ferroelectricity and ferromagnetism, in which the bistable states are encoded in charge or spin degrees offreedom1,2. Here we report the observation of bistable superlattice switching in monolayer TaIrTe4, a dual quantum spin Hall insulator3-5. Switching occurs between two lattice configurations with sharply contrasting periodicities. In particular, in a pristine monolayer, we observe the spontaneous emergence of a long-period superlattice that can be programmed on and off in a non-volatile manner by electrostatic tuning of low-energy electronic states. This switching toggles the system between two structural configurations with unit cell areas differing by two orders of magnitude. Mechanistically, our results reveal two independent and distinct instabilities, one in the lattice and the other in the quantum spin Hall electrons. These instabilities are coupled, leading to electrostatic control of lattice configurations with non-volatile memory. This finding is enabled by combining linear and nonlinear transport measurements6-13, Raman spectroscopy and scanning tunnelling microscopy, which probe complementary aspects of the underlying orders. Notably, this non-volatile memory stabilizes a spontaneous superlattice with a periodicity on the few-nanometre scale that remains robust across a wide doping range, persists over days and survives above 70 K. Our preliminary data also show the emergence of new insulating states at fractional superlattice fillings, which can be switched on and off together with the superlattice.

New Testament textual criticism in the twenty-first century continues to refine principles and approaches that have been part of this scholarly discipline since the development of the modern era of textual criticism. At the same time, even as New Testament textual criticism remains connected to its roots in pursuing the (re)construction of a critical text of the New Testament, more recent approaches have expanded the set of questions being asked by textual critics to include far more than simply the words of a New Testament text. In all of these developments, there is both “Old” in the “New” and “New” in the “Old,” resulting in New Testament textual criticism in the twenty-first century having become not only one of the more vibrant fields in New Testament studies but also having captured the popular imagination.

One efficient driver for atmospheric CO2 removal over 10-100 Ma timescales is silicate-rich rock weathering, which is notably favored in the context of arc magmatism (Gernon et al., 2021). The modeling of the past evolution of atmospheric CO2 therefore requires to finely reconstruct the evolution of past subduction zones, which is challenging due to the permanent recycling of oceanic lithosphere. One difficulty notably resides in the reconstruction of intra-oceanic arcs, which leave almost no direct imprints in the geological record, although they could significantly contribute to the atmospheric CO2 removal through silicate weathering, especially in the tropics (Gaillardet et al., 2011).We propose to test how the variability of intra-oceanic arcs can affect the amount of CO2 removed from the atmosphere through supercontinent cycles. To do so, we use 3D numerical models of whole-mantle convection self-generating Earth-like plate tectonics in order to quantify the temporal evolution of the number and length of intra-oceanic arcs, in a fully-dynamic context, independent of any plate reconstructions. We use the automatic plate tessellation algorithm MAPT3 based on the open-source library Topology ToolKit (Janin et al., 2025) to detect intra-oceanic subduction zones. We show that the total length of intra-oceanic arcs varies significantly depending on the continental configuration in the models. We then test the sensitivity of atmospheric CO2 absorption level through silicate weathering to mantle convective parameters, to the latitudinal distribution of the intra-oceanic arcs, their width and fraction above sea-level, and the potential effect of True Polar Wander. We show that in a fully-dynamic model, it is possible to reach the amount of extra-weathering required to possibly explain the atmospheric CO2 and temperature drops observed, especially during periods of continental aggregation. Nevertheless, the amount of intra-oceanic subduction zones in the geodynamic models varies over longer timescales than in the plate reconstruction, and cannot explain alone, rapid cooling events, such as during the Hirnantian (Marcilly et al., 2022).

Mesopelagic ecosystems are vital to the ocean’s health yet face unprecedented threats due to accelerating climate change. Lanternfish (family Myctophidae) are key sentinels of midwater ecosystem health because they dominate mesopelagic fish biomass and mediate energy, nutrient, and carbon transfer across ocean layers. Despite their ecological importance, very little is known about their potential response to climate change stressors due to logistical challenges when studying mesopelagic ecosystems. We use thousands of fossil fish otoliths (calcium carbonate ear stones) recovered from marine surface sediments to reconstruct lanternfish growth, body size and energetic investment across contrasting oceanographic regimes. We compare assemblages from the highly productive, but oxygen-poor Tropical Eastern Pacific (TEP) and the oligotrophic, well-ventilated Caribbean, to test how oxygen availability and food supply shape mesopelagic fish energetics across the Isthmus of Panama. Otoliths from marine sediments serve as a cost-efficient, powerful archive to overcome methodological barriers and allow us to reconstruct long-term changes in lanternfish dynamics. We quantify energetic changes in lanternfish assemblages by reconstructing lanternfish body size estimates and mean per-capita biomass from otolith measurements and growth trajectories derived from increment biochronologies. Our results reveal anomalously small lanternfish in the TEP today, despite the region’s tendency to host larger fishes relative to the Caribbean, providing the first indication that mesopelagic fish size is potentially related to oxygen limitation. We then extend this approach to fossil otoliths to explore changes before the closure of the Isthmus of Panama using the Late Miocene/Pliocene as an analog system for warmer than modern conditions to test how mesopelagic ecosystems might respond to future climate change. We find that lanternfish dominated Panama’s ancient fish assemblages in the Caribbean but declined in relative abundance toward the Isthmus closure, while their mean per-capita biomass remained stable over the past 8 Ma. These results imply higher lanternfish biomass during periods of prolonged warming and lower biomass under less productive, better-oxygenated Caribbean conditions created by the Isthmus uplift. Yet in contrast to Panama’s geological past, our results suggest that oxygen availability exerts a dominant control on lanternfish energetics and production in the modern TEP. By integrating otolith archives from deep time to the recent past, we mapped shifts in lanternfish energetics in response to major environmental changes, revealing their sensitivity to oxygen availability and indicating that projected ocean deoxygenation might constrain the energetic capacity of the mesopelagic zone in a future ocean.

Earth’s interior plays a fundamental role in the long-term evolution of the surface, climate, and biosphere. However, Earth's mantle evolution remains largely ambiguous, as imaging techniques are limited to present-day observations and geochemical or geological constraints apply to a non-global scale. Plate tectonic reconstructions coupled with convection models could provide constraints on the evolution of mantle structure. In this study, we employ both fully self-consistent and kinematically constrained mantle convection models[1]. The mantle rheology is temperature-, pressure-, phase-, and stress-dependent, with the latter represented through pseudo-plasticity. The novelty of this work lies in employing a composite rheology with “realistic” rheological parameters[2] in a fully three-dimensional geometry. By using both fully self-consistent models and plate-driven models, we aim to address the discrepancies in terms of long-term convective and tectonic behaviour that arise when forcing plate velocities onto the surface. The latter is done by imposing time-dependent surface velocity boundary conditions provided by a plate tectonic reconstruction[3].To evaluate the extent to which the models reproduce plate-like tectonics, we explore several independent constraints. In particular, we compute slab sinking rates and compare them to estimates inferred from seismic tomography[4]. Slab sinking rates in self-consistent models provide insight into the mantle’s rheology. For example, sinking rates that are lower than those based on tomographic and geological data may indicate an overly viscous mantle. Our results show that the slab sinking rate is generally higher in models with imposed plate velocities compared to fully self-consistent models. Furthermore, a tessellation algorithm[5] will be applied to the surface of the models to detect plates in the self-consistent models with plate-like behaviour. Based on these results, a plate-size frequency distribution can be calculated and compared to present-day Earth[6]. Results show that low yield stresses generate too many small plates, and too few large plates [Fig. 1]. In order to generate Earth-like plate tectonics, yield stress needs to be sufficiently high to reproduce the plate-size frequency distribution of present-day Earth, but also sufficiently low to facilitate a long-term mobile lid regime.[1] Tackley, P. J. (2008). Phys. Earth Planet. Inter. 171, 1–4.[2] Tackley, P. J., Ammann, M., Brodholt, J. P., Dobson, D. P., & Valencia, D. (2013). Icarus 225, 50–61.[3] Merdith, A. S., Williams, S. E., Collins, A. S., et al. (2021). Earth-Sci. Rev. 214, 103477.[4] Van der Meer, D. G., van Hinsbergen, D. J. J., & Spakman, W. (2018). Tectonophysics 723, 309–448.[5] Janin, A., Coltice, N., Chamot-Rooke, N., & Tierny, J. (2025). Nat. Geosci. 18, 1041–1047.[6] Bird, P. (2003). Geochem. Geophys. Geosyst. 4, 2001GC000252.

Though it has early modern roots, contemporary “Ignatian spirituality” represents a reconfiguration of nineteenth- and twentieth-century Jesuit spiritual culture. This article offers a genealogical account of a key element in that modern construction: the growing emphasis on Ignatius Loyola as a mystic and the eclipse of earlier, more ascetical understandings of both Ignatius and his Spiritual Exercises. The essay begins by examining key contributions of Jan Philipp Roothaan (1785–1855), the long-serving superior general of the Society of Jesus in the decades following its Restoration. Roothaan’s explicitly non-mystical and decidedly ascetical reading of the Exercises at once reflected and helped shape nineteenth-century Jesuit spiritual culture. The article then traces how this vision came under criticism in the early twentieth century. Renewed Catholic interest in mysticism, and increased attention to Jesuit sources—newly available in critical editions via the Monumenta Historica Societatis Iesu—fostered a reevaluation of Ignatius as a mystic in his own right. Over time, this shift came to color the interpretation of the Spiritual Exercises. Rather than a school of self-conquest, they came to be understood as a kind of mystical pedagogy. Changes in spiritual theology have had concrete implications for how the Exercises are given, as a concluding case study of the Ignatian Examen helps illustrate.

Mixed anion compounds offer unique opportunities to tune the redox properties of intercalation compounds. Among them, layered iron oxychloride (FeOCl) has long been envisioned as an energy-dense and sustainable alternative to layered oxides for Li–ion batteries. However, achieving full capacity has thus far remained elusive owing to detrimental solvent cointercalation typically observed in dilute liquid electrolytes and ionic liquids. In this work, we alleviate this limitation by developing a suitable electrolyte engineering approach and demonstrate that 1 Li atom can be reversibly intercalated in FeOCl. We demonstrate that solvent cointercalation can be suppressed in high-concentration electrolytes using a highly dissociating salt, lithium bis(fluorosulfonyl)imide (LiFSI), dissolved in solvents with low Li-solvent binding energy, including dimethylcarbonate and acetonitrile, achieving a capacity of 235 mAh/g and a material specific energy of 590 Wh/kg in its lithiated form. Combining X-ray absorption measurements at iron, oxygen, and chloride K-edges, we observe that the intercalation proceeds with a transition from distorted high-spin Fe3+ to low-spin Fe2+, while operando X-ray diffraction shows three successive biphasic processes associated with changes in interlayer spacing. Entropic potential measurements coupled with temperature-dependent cycling reveal a reversible cationic ordering event when half of the interlayer Li+ sites are filled. This ordering is associated with high activation energy and a slow phase-front diffusion, which does not prevent good cycling ability at room temperature even at high C-rate. Our work calls for revisiting through an electrolyte engineering approach energy dense and sustainable mixed anion materials previously discarded for their instability.

Fluid flow has a major effect on the aggregation and fragmentation of bacterial colonies. Yet, a generic framework to understand and predict how hydrodynamics affects colony size remains elusive. This study investigates how fluid flow affects the formation and maintenance of large colonial structures in cyanobacteria, using an experimental technique that precisely controls hydrodynamic conditions. We performed experiments on laboratory cultures and lake samples of the cyanobacterium Microcystis, while their colony size distribution was measured simultaneously by direct microscopic imaging. We demonstrate that EPS-embedded cells formed by cell division exhibit significant mechanical resistance to shear forces. However, at elevated hydrodynamic stress levels (exceeding those typically generated by surface wind mixing) these colonies experience fragmentation through an erosion process. We also show that single cells can aggregate into small colonies due to fluid flow. However, the structural integrity of these flow-induced colonies is weaker than that of colonies formed by cell division. We provide a mathematical analysis to support the experiments and demonstrate that a population model with two categories of colonies describes the measured size distributions. Our results shed light on the specific conditions wherein flow-induced fragmentation and aggregation of cyanobacteria are decisive and indicate that colony formation under natural conditions is mainly driven by cell division, although flow-induced aggregation could play a role in dense bloom events. These findings can be used to improve prediction models and mitigation strategies for toxic cyanobacterial blooms and also offer potential applications in other areas such as algal biotechnology or medical settings where the dynamics of biological aggregates play a significant role.

People who use drugs face barriers to accessing HIV prevention tools. The status-neutral model for HIV care starts with the HIV test and offers linkage to HIV treatment if the person tests positive and linkage to pre-exposure prophylaxis (PrEP) if the person tests negative. The goal of this study was to evaluate barriers and facilitators impacting the implementation of a status-neutral HIV model of care in the jail setting. Between June and August 2024, we recruited people working in and incarcerated in the jails operated by the Suffolk County Sheriff’s Department (Jail and House of Correction) for in-depth interviews. The Consolidated Framework for Implementation Research (CFIR) 2.0 guided interview development. Interviews were recorded, transcribed, coded, and analyzed using rapid thematic analysis (RTA) methods. Relevant themes were mapped onto CFIR domains. We conducted 28 interviews: 13 with correctional and clinical staff and 15 with incarcerated people. Clinical and administrative staff members indicated that strong relationships with state and local agencies and the state’s proactive approach to preventative carceral healthcare helped facilitate HIV treatment and prevention pathways. Incarcerated individuals identified issues in the system used to report health needs and unreliable test result delivery mechanisms as major barriers. Staff also identified barriers, including understaffing, but overwhelmingly endorsed the jails’ existing systems of accessing and delivering care. Findings identified multiple potential intervention targets to enhance a status-neutral approach to HIV testing and treatment in jail settings, including leveraging existing partnerships, and educational opportunities for staff. Strategies that reinforce a patient-centered institutional culture (with a focus on incarcerated individuals’ health), improve care continuity for transitions into and out of jail, and highlight gaps in healthcare delivery are critical for successful implementation of status-neutral HIV care in jails.