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The Effect of the Io Plasma Torus on Precise Orbit Determination and Gravity Recovery: Application to Europa Clipper
No full textThe neutral gases released by the intense volcanic activity of the Jupiter moon Io, once ionized by the Jupiter magnetic environment, give rise to a toroidal plasma distribution known as the Io plasma torus (IPT). Radio signals passing through charged-particle environments such as the IPT are heavily perturbed proportionally to the rate of change of the charged-particle distribution along the path of the radio wave. If not properly calibrated, the IPT may induce significant perturbation on the radiometric tracking link to Earth. The radio tracking signal is the main observable for the Gravity and Radio Science (G/RS) investigation on NASA's Europa Clipper, whose aim is to measure the gravity field, tidal response, and moment of inertia of Europa, and to precisely reconstruct the trajectory of the probe in support of other scientific investigations. In this work, we quantify the detrimental effects of the IPT on the radiometric observables. We show how these affect the products of the G/RS, and prove the necessity of accurate calibrations. We simulate different calibration strategies to mitigate its net perturbative effect, based on currently available models of the IPT. Considering that these models have been developed with Juno in mind, they are tailored to its orbital geometry and we show that they cannot be easily applied to other geometries. We conclude that, although the model-based calibration strategies can be very effective, further work will be needed to make them applicable to probes with a significantly different orbital geometry such as Europa Clipper or ESA's JUICE.The authors would like to thank P. Phipps (University of Maryland Baltimore County) for fruitful discussions and clarications. Work by G.C. was supported by NASA under award No. 80GSFC24M0006. Part of this research was carried out at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with the National Aeronautics and Space Administration (80NM0018D0004). A.M., M.Z., L. G.C., and P.T. acknowledge financial support from the Italian Space Agency through the Agreement 2021-13- HH.1-2023.https://iopscience.iop.org/article/10.3847/PSJ/add012/met
The Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) Project
No full textOvershooting storms are convective systems with updrafts that penetrate through the tropopause into the overlying stratosphere. These storms can rapidly transport a wide variety of chemical species and aerosols from the boundary layer and free troposphere directly to the stratosphere. The central plains of the U.S. and the Sierra Madre Occidental of Mexico are two of the global hotspots for overshooting convection. While the existence of these storms has been known for several decades, the amount of tropospheric air, including water vapor, trace gases, and aerosols, transported across the tropopause is poorly understood, as is their impact on the dynamics, chemistry, and radiative balance of the stratosphere. Climate models suggest that as Earth’s climate continues to warm, overshooting convection over the U.S. may increase, potentially causing changes to stratospheric composition and transport. To address these scientific questions, the NASA ER-2 high-altitude research aircraft flew 31 missions during the summers of 2021 and 2022 to make observations of the outflow from overshooting storms in the stratosphere over North America and the eastern Pacific Ocean as part of the Dynamics and Chemistry of the Summer Stratosphere (DCOTSS) project. The ER-2 carried a payload of 12 instruments to measure meteorological parameters, water and its isotopologues, trace gases, and aerosol properties. Ozone, water vapor, and aerosol sondes were also launched on balloons during the field deployments. This paper describes the science goals of the DCOTSS project, the aircraft measurement strategy, the data produced by the project, and highlights of science results to date.The Dynamics and Chemistry of the Summer Stratosphere Project was funded by the National Aeronautics and Space Administration as part of the Earth Venture Suborbital 3 Program managed by the Earth System Science Pathfinder Program Office. This includes the following grants: 80NSSC19K0341 to Texas A&M University, 80NSSC19K0326 to Harvard University, 80NSSC19K1399 to the University of Maryland, 80NSSC19K0342 to the Massachusetts Institute of Technology, 80NSSC19K0340 to the University of Miami, 80NSSC19K0343 to the University of North Dakota, 80NSSC19K0347 to the University of Oklahoma, 80NSSC19K1058 to Purdue University, 80NSSC19K0346 to Texas A&M University Corpus-Christi, 80NSSC19K0353 and 80NSSC24K0376 to the National Center for Atmospheric Research, 80NSSC24K0714 and 80NSSC24K1856 to the University Corporation for Atmospheric Research, 80NSSC19K1473 to the Bay Area Environmental Research Institute, 80NSSC24K0447 to the National Institute of Aerospace, and additional funding to the Naval Research Laborary and the NOAA Earth System Research Laboratories. Funding was also provided by the National Science Foundation to the National Center for Atmospheric Research under Cooperative Agreement No. 1852977. The project thanks the following NASA administrators for their leadership and support, particularly during the worst of the COVID-19 pandemic: Jennifer Olson, Melissa Yang Martin, Ken Jucks, Henry Selkirk, Bruce Tagg, Barry Lefer, and Jack Kaye.https://journals.ametsoc.org/view/journals/bams/aop/BAMS-D-24-0177.1/BAMS-D-24-0177.1.xm
Fiber-coupled broadband quantum memory for polarization-encoded photonic qubits
No full textVarious near-term quantum networking applications will benefit from low-loss, fiber-coupled photonic quantum memory devices with high efficiencies. We demonstrate a fiber-coupled loop-and switch quantum memory platform with a pass-through efficiency of ∼54% and an overall storage efficiency that scales as ∼0.5ᴺ⁺¹ where N is the number of storage cycles. We highlight the trade-off between memory lifetime and qubit accessibility in this platform by using two different storage cycle times of ∼40 ns and ∼0.5 µs, and demonstrate high fidelity storage and retrieval of ultra-broadband single-photon polarization qubits in both cases.This work was supported in part by National Science Foundation under Grant Award Number 2013464 and National Institute of Standards and Technology under Grant Number 60NANB24D106. S.C. thanks Adrian Udoviˆci´c for helpful discussions on quantum state tomography.http://arxiv.org/abs/2505.1063
Excellence in Research: Identification of absolute sea level rise and land subsidence from long-term tide gauge records along coasts of the Gulf of Mexico and the Chesapeake Bay
No full textThis depository, titled "U.S. Extreme Coastal Water Level Data and Charts", contains all datasets and Python code used to generate Figures 2, 3, and 4, as well as Supplementary Tables S1 through S5 from the associated study. The datasets include Mean Higher High Water (MHHW), 1% Extreme Water Level (1%EWL) in 1992, and Relative Sea-Level Rise (RSLR) projections from 2020 to 2150 at 10-year intervals, sourced from NOAA. Derived 1%EWL values from 2020 to 2150 at 10-year intervals were calculated based on these data. The depository also includes categorization results based on statistical analysis. All input files, processed data, and scripts for data visualization and analysis are provided. This work is primarily supported by the National Science Foundation (NSF) under the project Excellence in Research: Identification of Absolute Sea Level Rise and Land Subsidence from Long-Term Tide Gauge Records Along Coasts of the Gulf of Mexico and the Chesapeake Bay (NSF Award #2101056).Global warming causes worldwide sea level rising due to a combination of meltwater from glaciers and ice sheets and expansion of ocean water. As a result, flood risk and ecosystem change are elevated in the Gulf of Mexico and the Chesapeake Bay, two of the globe's hot spots, where the sea level rise is about two to four times greater than global mean sea level rise. The sustainability and resiliency of the nation's coastal communities to evolving needs of the environments in response to past and future sea level rise necessitates identification of it from long-term tide gauge records along the nation's coasts. This research will develop an innovative methodology to accurately identify and predict sea level rise along any coasts. The proposed research activities will impart an improved understanding of sea level rise and its adverse impacts on coastal communities, which thereby inspires scientists and engineers to face various environmental challenges caused by sea level rise. In order to disseminate new knowledge and research findings, the program plans to deliver lectures or talks with research results to K-12 students, college students in three undergraduate courses, and graduate students in four graduate courses in Civil Engineering at Morgan State University. One postdoctoral researcher and one graduate student will be hired each year to participate in the proposed research activities.
Gauged sea level rise comprises of absolute sea level rise, in light of the Earth's climate system change, and land subsidence, due to the Earth's geological system change. The latter change includes four sub-components: tectonic subsidence from basement rocks, basement rock creep, primary consolidation subsidence due to subsurface fluid withdrawal from compressible coastal aquifer systems and creep subsidence due to geohistorical overburden pressure of the same aquifer system. A novel piecewise equation of relative sea level rise comprising of absolute sea level rise and four sub-components of land subsidence can help scientists and engineers identify and project relative sea level rise value for adaptive engineering design and construction necessary with a view to increase the resilience of coastal communities against sea level rise as well as other natural hazards. To these ends, this project aims to raise public awareness of the importance of sea level rise in environmental sustainability and coastal community resilience in the coastal areas of the Mexico Gulf and the Chesapeake Bay and promote science, technology, engineering and mathematics (STEM) education for underrepresented minorities. This project is co-funded by the Geomorphology and Land-use Dynamics (GLD) Program and the Historically Black Colleges and Universities - Excellence in Research (HBCU-EiR) Program, along with support from Integrative and Collaborative Education and Research (ICER) funds of the NSF Geosciences Directorate.U.S National Science Foundation, Award #210105
Family Availability, ‘Kinlessness’, COVID Stringency, and Loneliness in 26 Countries
No full textLoneliness became an increasing concern during the COVID-19 pandemic, especially as countries enacted “physical distancing” mitigation measures. Under these conditions, older adults with limited family availability (e.g., unpartnered, childless, and “kinless”) might have been at higher loneliness risk, or perhaps were more accustomed to less social interaction. Using individual-level data from the Survey of Health, Ageing and Retirement in Europe (SHARE) and country-level data from the Oxford Coronavirus Government Response Tracker (OxCGRT), we analyzed loneliness outcomes for 34,943 older Europeans in 26 countries to examine associations between various types of family availability and loneliness under different COVID-19 stringency conditions. More stringent COVID-19 country contexts and being unpartnered were associated with loneliness, but “kinless” older adults had similar risk of loneliness as unpartnered older adults, underscoring the highly protective role of partnership. We discuss these findings considering the growing global population with limited family ties and make recommendations for future pandemic mitigation efforts.The SHARE data collection has been funded by the European Commission DG RTD through FP5 QLK6 CT 2001 00360 FP6 SHARE I3 RII CT 2006 062193 COMPARE CIT5 CT 2005 028857 SHARELIFE CIT4 CT 2006 028812 FP7 SHARE PREP GA No211909 SHARE LEAP GA No227822 SHARE M4 GA No261982 DASISH GA No283646 and Horizon 2020 SHARE DEV3 GA No676536 SHARE COHESION GA No870628 SERISS GA No654221 SSHOC GA No823782 SHARE COVID19 GA No101015924 and by DG Employment Social Affairs & Inclusion through VS 2015 0195 VS 2016 0135 VS 2018 0285 VS 2019 0332 and VS 2020 0313 Additional funding from the German Ministry of Education and Research the Max Planck Society for the Advancement of Science the U S National Institute on Aging U01 AG09740 13S2 P01 AG005842 P01 AG08291 P30 AG12815 R21 AG025169 Y1 AG 4553 01 IAG BSR06 11 OGHA 04 064 HHSN271201300071C RAG052527A and from various national funding sources is gratefully acknowledged see https www.share-project.orghttps://journals.sagepub.com/doi/10.1177/0164027525133462
Large-scale portfolio optimization with variational neural annealing
No full textPortfolio optimization is a routine asset management operation conducted in financial institutions around the world. However, under real-world constraints such as turnover limits and transaction costs, its formulation becomes a mixed-integer nonlinear program that current mixed-integer optimizers often struggle to solve. We propose mapping this problem onto a classical Ising-like Hamiltonian and solving it with Variational Neural Annealing (VNA), via its classical formulation implemented using autoregressive neural networks. We demonstrate that VNA can identify near-optimal solutions for portfolios comprising more than 2,000 assets and yields performance comparable to that of state-of-the-art optimizers, such as Mosek, while exhibiting faster convergence on hard instances. Finally, we present a dynamical finite-size scaling analysis applied to the S&P 500, Russell 1000, and Russell 3000 indices, revealing universal behavior and polynomial annealing time scaling of the VNA algorithm on portfolio optimization problems.We thank Mahmoud El Mabrouk, Hanna Morilhas, Roger Melko and Juan Carrasquilla for fruitful discussions. EMI acknowledges support from the Natural Sciences and Engineering Research Council of Canada (NSERC). yiyaniQ acknowledges support from the Perimeter Institute for Theoretical Physics. Research at Perimeter Institute is supported in part by the Government of Canada through the Department of Innovation, Science and Economic Development Canada and by the Province of Ontario through the Ministry of Economic Development, Job Creation and Trade. NR acknowledges support from the Mitacs Accelerate Umbrella program. Computer simulations were made possible thanks to the Digital Research Alliance of Canada clusterhttp://arxiv.org/abs/2507.0715
STGen: A Novel Lightweight IoT Testbed for Generating Sensor Traffic for the Experimentation of IoT Protocol and its Application in Hybrid Network
No full textA Wireless Sensor Network (WSN) is a network that does not rely on a fixed infrastructure and consists of numerous sensors, such as temperature, humidity, GPS, and cameras, equipped with onboard processors that manage and monitor the environment in a specific area. As a result, building a real sensor network testbed for verifying, validating, or experimenting with a newly designed protocol presents considerable challenges in adapting a laboratory scenario due to the significant financial and logistical barriers, such as the need for specialized hardware and large-scale deployments. Additionally, WSN suffers from severe constraints such as restricted power supply, short communication range, limited bandwidth availability, and restricted memory storage. Addressing these challenges, this work presents a flexible testbed solution named STGen that enables researchers to experiment with IoT protocols in a hybrid environment that emulates WSN implementations with the physical Internet through a dedicated physical server named STGen core, which receives sensor traffic and processes it for further actions. The STGen testbed is lightweight in memory usage and easy to deploy. Most importantly, STGen supports large-scale distributed systems, facilitates experimentation with IoT protocols, and enables integration with back-end services for big data analytics and statistical insights. The key feature of STGen is the integration of real-world IoT protocols and their applications with WSN. Its modular and lightweight design makes STGen efficient and enables it to outperform other popular testbeds, such as Gotham and GothX, reducing memory usage by 89\%. While GothX takes approximately 26 minutes to establish a large topology with four VM nodes and 498 Docker nodes, STGen requires only 1.645 seconds to initialize the platform with 500 sensor nodes.http://arxiv.org/abs/2504.1772
Molecular and Structural Determinants of Melanopsin Signaling Specificity
No full textPurpose: The core question I address is mechanistic: how can one GPCR choose different G-proteins and second messengers depending on the cell it sits in? The main goal of this work is to identify a mechanism through which melanopsin engages in distinct signaling cascades, which would explain the observed heterogeneity of signaling seen in vivo. An overarching goal is to show, using melanopsin as a prototypical GPCR, that a regulatory protein network unique to each cell type ultimately determines the outcome of GPCR signaling. We hypothesize that RGS proteins act as a downstream filter of G-proteins, inhibiting certain signals in M1 or M4 ipRGCs, enabling melanopsin to diversify its signaling cascade to suit the needs of the individual cell types where it is expressed. Method: A combination of transcriptomics and RNAscope immunohistochemistry that labeled individual subtypes of ipRGC. Bioluminescence resonance energy transfer (BRET) assays were optimized for stoichiometry and stimulus length to achieve optimal and reproducible results with opsin GPCRs. We performed electrophysiology in mouse lines specifically labeling M1 or M4 ipRGCs, with targeted Designer Receptor Exclusively Activated by Designer Drugs (DREADD) expression to evaluate preference for a Gq or Gs cascade. Sequence alignment and computationally derived structural modeling were employed to evaluate a series of melanopsin-DREADD chimeras.
Results: We show that RGS proteins are differentially expressed among ipRGC subtypes. When RGS proteins are combined to create an M1- or M4-like profile, the M1-like RGS proteins caused melanopsin to signal Gi greater than Gq. Furthermore, melanopsin can produce cAMP downstream of Gq signaling alone, We tested both Gq- and Gs-DREADDs in M1 and M4 ipRGCs and found that they activated both cell types similarly. Separate experiments focused on the role of PKA phosphorylation of melanopsin produced the expected result of reducing Gq coupling, which we confirmed occurs with Gs signaling of the B2AR as well.
Conclusion: Our data show that melanopsin’s sequence and structure provides a broad G-protein signaling potential, while subtype-specific RGS repertoires and activity-dependent PKA phosphorylation filter that signaling to the single pathway observed in each ipRGC subtype. Together, these results support a two-tier scheme. The first is upstream signaling, where sequence and structure of a GPCR defines which G-proteins can be activated. The second is regulation of downstream signaling, where cell-restricted RGS determine which G-protein pathways ultimately drive functional activity, and an activity–driven PKA regulation which tunes the magnitude of signaling. This work demonstrates that G-protein pathway bias can arise solely from intracellular context, without changing ligands or receptor
Inviting Light: A Prismatic Public Art Initiative Hits the Switch
No full textBloomberg Philanthropies’ $1M Public Art Challenge “encourages mayors to partner with artists, elevating the creative sector when developing solutions to significant urban issues”https://bmoreart.com/2025/03/inviting-light-a-prismatic-public-art-initiative-hits-the-switch.htm
Hamiltonian quantum gates -- energetic advantage from entangleability
No full textHamiltonian quantum gates controlled by classical electromagnetic fields form the basis of any realistic model of quantum computers. In this letter, we derive a lower bound on the field energy required to implement such gates and relate this energy to the expected gate error. We study the entangleability (ability to entangle qubits) of Hamiltonians and highlight how this feature of quantum gates can provide a means for more energetically efficient computation. Ultimately, we show that a universal quantum computer can be realized with vanishingly low energetic requirements but at the expense of arbitrarily large complexity.We would like to thank E. Doucet for insightful discussions S.D. acknowledges support from the John Templeton Foundation under Grant No. 62422http://arxiv.org/abs/2507.0175