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This presentation provides an overview of key concepts in arms control, a history of nuclear arms control agreements, some of the contemporary challenges and opportunities in the field, a discussion of the process for negotiating arms control agreements, and updates on recent developments.
Mission and Vision Statements for the U.S. Department of Energy (DOE)’s Atmospheric Radiation Measurement (ARM) Climate Research Facility Mission The ARM Climate Research Facility, a DOE scientific user facility, provides the climate research community with strategically located in situ and remote-sensing observatories designed to improve the understanding and representation, in climate and earth system models, of clouds and aerosols as well as their interactions and coupling with the Earth’s surface. Vision To provide a detailed and accurate description of the Earth atmosphere in diverse climate regimes to resolve the uncertainties in climate and Earth system models toward the development of sustainable solutions for the nation's energy and environmental challenges.
Radiation mapping is a desirable task to automate because of the inherent risks involved and its tedious nature. A novel system was designed to address this by combining various existing technologies, utilizing behavior-based robotics and Bayesian optimization. The system uses a quadruped robot equipped with a manipulator and gamma detector to take measurements at locations that are selected based on the uncertainty of a surrogate model used to estimate the true radiation field. The robot uses input from the world with depth cameras to avoid collisions with the robot’s body, and unreachable points for the end effector are addressed by both allowing for a soft collision with the environment to occur, prompting the system to abandon that point, and varying the exploration tendency of the optimization based on consecutive collisions. This approach provides unique traversability and adaptability over other strategies in the literature. Experiments were performed by placing a Cesium-137 source on the ground and varying geometric setups and an optimization parameter demonstrating the adaptability to diverse environments and the increased robustness resulting from the designed behavior. The results additionally demonstrate that dynamically adjusting the optimization algorithm’s exploration tendency based on the arm’s collision history improves the system’s ability to navigate cluttered environments and construct accurate radiation maps without getting stuck in unreachable areas.
“Now!” With that word, the Atomic Age – and the era of nuclear weapons testing – dawned. The advent of World War II’s first irresistible weapon, which had been secretly tested in the New Mexico desert in July 1945, would help hasten the inevitable: complete victory for the Allies. Codenamed Trinity, the test was the first of over a thousand conducted by the United States between 1945 and 1992. Nuclear weapons would change future clashes as well. The looming Cold War, with roots stretching all the way back to 1917, was history’s first conflict between two, major nations armed with nuclear weapons. It is clear the existence of those weapons played an important role in maintaining a tenuous peace between the United States and the Soviet Union; it is also clear nuclear weapons testing played a prominent role in fueling both the arms race and the success of deterrence. Yet, the history of nuclear weapons testing is rarely remembered, even though nuclear tests have been performed in the very recent past. Of the estimated 2,000-plus nuclear tests ever performed, the U.S. is responsible for approximately half. This is the story of U.S. full-scale nuclear weapons testing.
ABSTRACT We obtain a quantitative star formation history (SFH) of a shell-like structure (‘shell’) located in the northeastern part of the Small Magellanic Cloud (SMC). We use the Survey of the MAgellanic Stellar History to derive colour–magnitude diagrams (CMDs), reaching below the oldest main-sequence turnoff, from which we compute the SFHs with CMD-fitting techniques. We present, for the first time, a novel technique that uses red clump (RC) stars from the CMDs to assess and account for the SMC’s line-of-sight depth effect present during the SFH derivation. We find that accounting for this effect recovers a more accurate SFH. We quantify an $\sim$7 kpc line-of-sight depth present in the CMDs, in good agreement with depth estimates from RC stars in the northeastern SMC. By isolating the stellar content of the northeastern shell and incorporating the line-of-sight depth into our calculations, we obtain an unprecedentedly detailed SFH. We find that the northeastern shell is primarily composed of stars younger than $\sim$500 Myr, with significant star formation enhancements around $\sim$250 and $\sim$450 Myr. These young stars are the main contributors to the shell’s structure. We show synchronicity between the northeastern shell’s SFH with the Large Magellanic Cloud’s (LMC) northern arm, which we attribute to the interaction history of the SMC with the LMC and the Milky Way (MW) over the past $\sim$500 Myr. Our results highlight the complex interplay of ram pressure stripping and the influence of the MW’s circumgalactic medium in shaping the SMC’s northeastern shell.
The U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility held a two-day workshop at the National Science Foundation National Center for Atmospheric Research in Boulder, Colorado in November 2023 to discuss the history and future of the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) activity. LASSO is a suite of data products focused on supplementing ARM observations with high-resolution modeling. The workshop used a hybrid format with 15 invited, in-person attendees and 36 virtual attendees logging in for portions of the workshop. Many topics were covered at the workshop, with this report reflecting the ensuing discussion. Some topics discussed had clear conclusions while others require further thought, given the breadth of topics included in a short workshop.
The Treaty on the Nonproliferation of Nuclear Weapons (NPT), with its quinquennial review conferences (RevCons), has become the foundation of the international nonproliferation regime over the course of its 50-year history. With more states parties than any other arms control agreement (currently 191), the Treaty provides a legally binding framework for all states parties, constraining proliferation of nuclear weapons and committing the five recognized states who possess nuclear weapons to work toward disarmament. The NPT has enjoyed wide success in constraining the spread of nuclear weapons. Only one state party has left the agreement and gone on to acquire these weapons, and the overall track record of compliance with IAEA safeguards has been robust. However, for all its effectiveness in the area of nonproliferation, its achievements on the disarmament front have been relatively unimpressive. While the NWS – most notably the United States and the Soviet Union/Russia – have decreased the overall size of their nuclear arsenals significantly since 1970, these arsenals have remained an important feature of NWS security policies. The limited progress towards disarmament has created friction between the NNWS and NWS and has been the source of mounting tension within the NPT regime. The 2020 RevCon, the 50th anniversary of the NPT and 25th anniversary of its indefinite extension, faces a range of contentious challenges, old and new, which call into question the Treaty’s future viability.
Mild traumatic brain injury (TBI) is associated with persistent sleep-wake dysfunction, including insomnia and circadian rhythm disruption, which can exacerbate functional outcomes including mood, pain, and quality of life. Present therapies to treat sleep-wake disturbances in those with TBI (e.g., cognitive behavioral therapy for insomnia) are limited by marginal efficacy, poor patient acceptability, and/or high patient/provider burden. Thus, this study aimed to assess the feasibility and preliminary efficacy of morning bright light therapy, to improve sleep in Veterans with TBI (NCT03578003). Thirty-three Veterans with history of TBI were prospectively enrolled in a single-arm, open-label intervention using a lightbox (~10,000 lux at the eye) for 60-minutes every morning for 4-weeks. Pre- and post-intervention outcomes included questionnaires related to sleep, mood, TBI, post-traumatic stress disorder (PTSD), and pain; wrist actigraphy as a proxy for objective sleep; and blood-based biomarkers related to TBI/sleep. The protocol was rated favorably by ~75% of participants, with adherence to the lightbox and actigraphy being ~87% and 97%, respectively. Post-intervention improvements were observed in self-reported symptoms related to insomnia, mood, and pain; actigraphy-derived measures of sleep; and blood-based biomarkers related to peripheral inflammatory balance. The severity of comorbid PTSD was a significant positive predictor of response to treatment. Morning bright light therapy is a feasible and acceptable intervention that shows preliminary efficacy to treat disrupted sleep in Veterans with TBI. A full-scale randomized, placebo-controlled study with longitudinal follow-up is warranted to assess the efficacy of morning bright light therapy to improve sleep, biomarkers, and other TBI related symptoms.
The crisis of arms control is obvious and broadly discussed among states, within the world’s expert community and to a lesser extent the media. This crisis has at least three building blocks: Russia continues to violate or undermine key arms control treaties and commitments; China rejects to join the existing arms control architecture; and both countries heavily invest in the modernization of their armed forces, including development of the nuclear arsenals. In the current highly competitive environment, arms control is more difficult to achieve and is likely to accomplish less than what was optimistically anticipated a generation ago. The growing pressure to “save arms control at all cost”, often expressed by the Western expert community, further complicates the situation. The excessively aspirational and ideological approach to arms control – in which arms control, disarmament, and non-proliferation (ADN) become a silver bullet solution – is as dangerous as security and defence policies which entirely exclude ADN. As James Cameron rightly points out, “history should teach policy-makers to look beyond formulae for strategic stability to other ways in which arms control can help to contain disruptive challenges to the balance of power and minimize the chances of war”.
Background: Hip strength is an important factor for control of the lumbo-pelvic-hip complex. Deficits in hip strength may affect throwing performance and contribute to upper extremity injuries. Hypothesis: Deficits in hip abduction isometric strength would be greater in those who sustained an upper extremity injury and hip strength would predict injury incidence. Study Design: Prospective cohort study. Level of Evidence: Level 3. Methods: Minor League baseball players (n = 188, age = 21.5 ± 2.2 years; n = 98 pitchers; n = 90 position players) volunteered. Hip abduction isometric strength was assessed bilaterally with a handheld dynamometer in side-lying position, expressed as torque using leg length (N·m). Hip abduction strength asymmetry was represented by [(trail leg/lead leg) × 100]. Overuse or nontraumatic throwing arm injuries were prospectively tracked. Poisson regression models were used to estimate relative risk ratios associated with hip asymmetry; confounders, including history of prior overuse injury in the past year, were included. Results: Hip abduction asymmetry ranged from 0.05% to 57.5%. During the first 2 months of the season, 18 players (n = 12 pitchers) sustained an upper extremity injury. In pitchers, for every 5% increase in hip abduction asymmetry, there was a 1.24 increased risk of sustaining a shoulder or elbow injury. No relationship between hip abduction strength and injury was observed for position players. Conclusion: Hip abduction asymmetry in pitchers was related to subsequent upper extremity injuries. The observed risk ratio indicates that hip abduction asymmetry may contribute a significant but small increased risk of injury. Clinical Relevance: Hip abduction muscle deficits may affect pitching mechanics and increase arm stress. Addressing hip asymmetry deficits that exceed 5% may be beneficial in reducing upper extremity injury rates in pitchers.
Abstract This study estimates the meteorological covariations of aerosol and marine boundary layer (MBL) cloud properties in the eastern North Atlantic (ENA) region, characterized by diverse synoptic conditions. Using a deep‐learning‐based clustering model with mid‐level and surface daily meteorological data, we identify seven distinct synoptic regimes during the summer from 2016 to 2021. Our analysis, incorporating reanalysis data and satellite retrievals, shows that surface aerosols and MBL clouds exhibit clear regime‐dependent characteristics, whereas lower tropospheric aerosols do not. This discrepancy likely arises from synoptic regimes determined by daily large‐scale conditions, which may overlook air mass histories that predominantly dictate lower tropospheric aerosol conditions. Focusing on three regimes dominated by northerly winds, we analyze the Atmospheric Radiation Measurement Program (ARM) ENA observations on Graciosa Island in the Azores. In the subtropical anticyclone regime, fewer cumulus clouds and more single‐layer stratocumulus clouds with light drizzle are observed, along with the highest cloud droplet number concentration (Nd), surface cloud condensation nuclei (CCN) and surface aerosol levels. The post‐trough regime features more broken or multi‐layer stratocumulus clouds with slightly higher surface rain rate, and lower Nd and surface CCN levels. The weak trough regime is characterized by the deepest MBL clouds, primarily cumulus and broken stratocumulus clouds, with the strongest surface rain rate and the lowest Nd, surface CCN and surface aerosol levels, indicating strong wet scavenging. These findings highlight the importance of considering the covariation of cloud and aerosol properties driven by large‐scale regimes when assessing aerosol indirect effects using observations.
This presentation provides an overview of cryptography starting with the Spartan Scytale used extensively during the Peloponnesian wars up through present day. Cryptography and cryptanalysis developed side by side in arms race. Algorithm development stagnated pending cracking. Once a method of crypto was cracked, development took off. Cryptography and cryptanalysis drove developments in math, linguistics, information theory, and quantum theory, and pushed development of the first computers.
This book is a comprehensive history of Brazil's nuclear activities and diplomacy. The author provides an in-depth explanation of the country's decision to give up the nuclear arms option and to accept nonproliferation norms after decades of opposition.
Processes mediating the coupling of terrestrial, aquatic, biospheric, and atmospheric systems influence weather, climate, and ecosystem dynamics via transfer of energy, momentum, water, and carbon (or other species). These exchange processes are quantified by measurements of near-surface turbulent fluxes. Understanding processes at these interfaces provides insight toward understanding and predicting current and future states within the Earth system. The Atmospheric Radiation Measurement (ARM) user facility has been conducting measurements of near-surface turbulent fluxes since the early 1990s at long-term fixed locations and shorter-term mobile deployments across the Earth. ARM has utilized two established methods for conducting these measurements: energy balance Bowen ratio (EBBR) and eddy covariance (EC). Primary measurements from the former include sensible and latent heat flux, while the latter also measures fluxes of momentum and carbon (primarily carbon dioxide, with methane fluxes measured at two locations to date). The EBBR systems have been deployed at 22 locations, and, to date, the EC systems have been deployed at over 50 sites, with plans for additional novel site locations in the future. Herein, the history, evolution, and key aspects of these instrument systems are documented, along with information on data quality assurance and post-processing, as well as best use practices. Additionally, three data validation experiments were recently conducted, and their key findings are summarized. Finally, ancillary datasets acquired by ARM, which can contextualize and aid interpretation of the near-surface turbulent flux measurements, are discussed. The datasets described herein include the eddy correlation flux measurement system: 30ECOR (https://doi.org/10.5439/1879993, Sullivan et al., 1997), 30QCECOR (https://doi.org/10.5439/1097546, Gaustad, 2003), ECORSF (https://doi.org/10.5439/1494128, Sullivan et al., 2019a), and associated AmeriFlux and Methane Value-Added Product, AMCMETHANE (https://doi.org/10.5439/1508268, Billesbach, 2011); the energy balance Bowen ratio system: 30EBBR (https://doi.org/10.5439/1023895, Sullivan et al., 1993) and 30BAEBBR (https://doi.org/10.5439/1027268, Gaustad and Xie, 1993); and the carbon dioxide flux measurement system: CO2FLX (https://doi.org/10.5439/1287574, https://doi.org/10.5439/1287575, https://doi.org/10.5439/1287576, Koontz et al., 2015a, b, c; https://doi.org/10.5439/1989774, https://doi.org/10.5439/1989776, https://doi.org/10.5439/1992202, Biraud and Chan, 2002a, b, c). These data can be found by searching the above data stream names at https://adc.arm.gov/discovery/#/results/ (last access: 8 September 2025).
On February 1, 2019, the United States and Russia withdrew from the three-decades old Intermediate-Range Nuclear Forces (INF) treaty. Events precipitating the withdrawal were allegations by both the United States and Russia of a variety of treaty violations. Until that point, the treaty had been a centerpiece of arms control and a key agreement of the global security architecture. The absence of such a pillar has the potential destabilize the status quo of arms control, creating significant uncertainty in global nuclear stability and security. In this paper, we present a historical review as overture to an analysis on the impacts of this development on force structure. This analysis examines the changes in U.S., Russian, and Chinese nuclear forces which may occur as a result of the treaty's demise. The article concludes with commentary on potential actions to preserve stability in a post-INF world.
Abstract New species of the pinnotherid crab genus GlassellaCampos & Wicksten, 1997 are described from western Atlantic waters along the east and west coasts of Florida, with the generic assignment of one being provisional. Glassella chaneyin. sp., Glassella martinin. sp., and Glassella taylorin. sp., all morphologically resemble the long-known species G. floridana (Rathbun, 1918) and overlap part of its distributional range, there occupying similar habitats and at least sometimes found with similar hosts. While genomic DNA sequencing has previously established the generic assignment of G. floridana, small sizes and suboptimal preservation histories of specimens representing the three new species have rendered all sequencing attempts unsuccessful, and thus not allowed their inclusion in molecular phylogenetic analyses. To facilitate present morphological comparisons, a rediagnosis of G. floridana was undertaken, and previously published illustrations were augmented, the latter now including figures of its previously undescribed male first gonopod and gonopodal plate. Comparisons of G. floridana to the three new species reveal striking diagnostic differences between all four species in their male first gonopods and varied configurations in the gonopodal plate or its probable homologs. These characters support the otherwise established separation of G. floridana from its congeners on the basis of its more strongly armed flexor margins of the fourth and fifth pereopods. In G. taylorin. sp., representing the smallest known member of Glassella, development of the third maxilliped and male first gonopod is so exceptional as to suggest the species may warrant eventual assignment to a separate genus.
The Large Magellanic Cloud (LMC) and Small Magellanic Cloud (SMC) are the Milky Way’s nearest interacting galaxy pair, offering a unique laboratory for studying tidal effects on galactic disks. Despite extensive survey efforts, the 3D geometry of the Magellanic Clouds, particularly the putative warp of the LMC, remains poorly constrained due to incompleteness in their crowded centers and the low stellar density of their peripheries, which demand wide-field coverage. Using red clump (RC) stars as standard candles, corrected for age- and metallicity-dependent population effects with empirically calibrated color–magnitude relations and spatially resolved star formation histories, we construct the most detailed distance map of the Magellanic system to date. Based on ∼2.3 million RC stars from Gaia Data Release 3 combined with modern reddening maps, we measure median heliocentric distances of 50.62 ± 2.32 kpc for the LMC (to ∼23°) and 60.75 ± 2.85 kpc for the SMC (to ∼12°). The maps reveal substructures including the LMC Northern Arm, southern hooks, the Magellanic Bridge, and SMC peripheral overdensities, with refreshed distance estimates. Fitting the LMC disk within 7° yields a global inclination of $i=25\mathop{.}\limits^{^\circ }32\pm 0\mathop{.}\limits^{^\circ }10$ and a line-of-nodes position angle of $\theta = 142\mathop{.}\limits^{^\circ }34\pm 0\mathop{.}\limits^{^\circ }21$. Most strikingly, we find the LMC periphery is warped azimuthally into a U-shaped structure reaching a vertical amplitude of ∼7 kpc at a radius of ∼15 kpc. In future work, we will perform detailed comparisons with live N-body simulations to assess possible formation scenarios for the LMC warp.
Deeper reductions in the nuclear arsenals will require better understanding of historic fissile material management and production. The concept of “nuclear archaeology” has been considered since the 1990s to provide the tools and methods to develop independent production estimates, primarily based on nuclear forensic techniques. Here, we propose to add a framework for reconstructing the history of a nuclear program that complements traditional nuclear archaeology techniques by examining the role of operating records to support such an effort. As a test case, we use the JEEP II reactor, a 2 MW civilian research reactor at Norway’s Institute for Energy Technology (IFE), in operation for more than fifty years, however, recently shut down permanently. We have collected, analyzed, and started to preserve the reactor’s operating records, which exist on both analog and digital media, and to simulate parts of its history using OpenMC/ONIX neutronics calculations. Here, a particular focus of this project has been on digital data curation and preservation to confirm and maintain the integrity, authenticity, and provenance of these records. In developing guidelines for best practices that conform to existing standards for long-term digital preservation and curation, we hope this project can help lay the basis for future nuclear archaeology efforts to support nuclear arms control and disarmament.