MD-SOAR Maryland Shared Open Access Repository
Not a member yet
34521 research outputs found
Sort by
Predicted Arctic sea ice cover in the GEOS S2S system, version 3
No full textMeeting US Interagency Arctic Research Policy Committee, Virtual, June 17, 2025. Authors - GMAO S2S Team: Andrea Molod, Bin Zhao, Lauren Andrews, Nathan Arnold, Donifan Barahona, Anna Borovikov, Yehui Chang, Anton Darmenov, Anthony DeAngelis, Abdullah Al Fahad, Eric Hackert, Weiyan Jiang, Annika Jersild, Kyu-myong Kim, Zhao Li, Young-Kwon Lim, Yu-Na Lim, Robert Lucchesi, Michael Mehari, Kazumi Nakada, Amidu Oloso, William Putman, Li Ren, Anastasia Romanou, Veronica Ruiz Xomchuk, David Russell, Mark Solomon, Aaron Stubblefield, Yuri Vikhliaev, Priyanka YadovArctic sea ice extent is a significant climate variable and a key indicator of Arctic conditions. With less sea ice, there is an expectation of an increased human presence in the Arctic related to commerce, military, and indigenous activities. Seasonal predictions of the sea ice cover are important for assessing our understanding of the associated physical processes, and for the adequate planning of various endeavors. Many centers continue to provide routine seasonal forecasts of sea ice extent; methods continue to be explored.Sponsors: Interagency Arctic Research Policy Committee. Funding Number(s) CONTRACT_GRANT: 80NSSC23M0011https://ntrs.nasa.gov/citations/2025000638
A stochastic tiling model of mean nearest-neighbor distances in three-dimensional uniform random distributions
No full textThe mean nearest-neighbor distance is an important clustering/ordering metric in quantitative spatial analysis of microstructures; especially for materials containing particles or voids. Nearest-neighbor distance (d**NN) distributions in three-dimensional (3D), random-sequential-addition, uniform, hard-sphere, computer-generated patterns have been studied for volume fractions from 0.0001 to 0.35. Normal distributions can well fit these d**NN distributions and they provide insight into the study of nearest-neighbor (NN) metrics such as means, medians, and modes. Furthermore, we report on the development of an estimator for the 3D mean d**NN (μ**NN) based upon stochastic tiling. Stochastic tiling models involve random rotations of polyhedral space-filling tiles which allows the calculation of the probabilities for d**NN distributions. Solutions are presented for volume fractions ≈0.10 to the cubic theoretical maximum of ≈0.52. Extrapolating solutions to lower volume fractions also provides reasonable estimates. There is good agreement between the μ**NN estimates compared to the computer-generated random patterns. In the volume fraction region where deviations from these estimates exist, there is an apparent transition in the relationship between the fitted normal distribution means and the NN distance means at a volume fraction ≈0.25. Suggestions for areas of future research are highlighted.
**subscripthttps://jmsh.springeropen.com/articles/10.1186/s41313-025-00068-
The Challenge of Balancing Taxation and Spending
No full textWith Montgomery County, MD, in the throes of budget season, Sunil Dasgupta talks with the county’s Chief Administrative Officer Rich Madaleno about how the budget balance taxation and services. Music by Frederick, MD,- based country-folk singer-songwriter Susanna Laird.https://open.spotify.com/episode/1p2NVbPPryZwVZ9ox0ltW
I Hate the News Apr 22
No full textThe weekly news analysis from I Hate Politics: SCOTUS hears Montgomery County, MD, LGBTQ books opt-out case. Can public education be apolitical? MoCo Executive Marc Elrich vetoes a tax rebate bill for office to apartment conversions. MD Transportation Secretary Paul Wiedefeld responds to NTSB criticism that the state did not evaluate the Chesapeake Bay Bridge or the Key Bridge in Baltimore for strength. DC tries to maneuver around Congressional budget constraints. A new climate cost report from MD Comptroller Brooke Lierman on Earth Day. And more. Music by Seth Kibel and Friends.https://open.spotify.com/episode/0odhgQW8GF1fijOIwVzwq
A spectrum of tectonic processes at coronae on Venus revealed by gravity and topography
No full textCoronae on Venus are key to understanding the planet’s geodynamics. Their formation is often linked to plume-lithosphere interactions, with some coronae showing signs of plate boundary-like processes such as subduction. However, the low resolution of Venus gravity data limits detailed analysis of these features. Using 3D geodynamic models, we predict gravity signals under various plume-induced corona formation scenarios. Comparing these predictions to observations, we show that combining topography and gravity data is more effective for understanding dynamic processes than using topography alone. Of the 75 resolved coronae, gravity indicates buoyant mantle material beneath 52. We predict a range of plume-lithosphere interactions and activity stages across these coronae. Moreover, we find that the limited resolution of the Magellan gravity field can obscure gravity signatures otherwise indicative of plume activity. The upcoming VERITAS mission will greatly improve gravity resolution, which will resolve 427 coronae, enhancing our understanding of Venus’ lithospheric structure and geodynamics. , Gravity and topography data reveal diverse mantle activity styles beneath Venus’ coronae and potentially hidden signals.GC is supported by nASA under award no 80GSFC24M0006 For the majorityof this work AG has been supported by the Swiss national Science Foundation PostdocMobility Grant P500Pn21729 with additional support by the Seismological laboratoryCalifornia institute of technology and the veRitAS project at the Jet Propulsion laboratory inaddition AJPG acknowledges funding from the Center for Space and habitability CSh atthe University of Bern and nCCR PlanetS supported by the Swiss national Science Foundationunder grant 51nF40205606 this research was partially conducted at the Jet Propulsionlaboratory California institute of technology under contract 80nM0018d0004 with thenASAhttps://www.science.org/doi/10.1126/sciadv.adt593
Determining the origin of the X-ray emission in blazars through multiwavelength polarization
No full textThe origin of the high-energy emission in astrophysical jets from black holes is a highly debated issue. This is particularly true for jets from supermassive black holes, which are among the most powerful particle accelerators in the Universe. So far, the addition of new observations and new messengers have only managed to create more questions than answers. However, the newly available X-ray polarization observations promise to finally distinguish between emission models. We use extensive multiwavelength and polarization campaigns as well as state-of-the-art polarized spectral energy distribution models to attack this problem by focusing on two X-ray polarization observations of blazar BL Lacertae in flaring and quiescent γ-ray states. We find that, regardless of the jet composition and underlying emission model, inverse-Compton scattering from relativistic electrons dominates at X-ray energies.This work was supported by NSF grant AST-2109127. E. L. was supported by Academy of Finland projects 317636 and 320045. We acknowledge funding to support our NOT observations from the Finnish Centre for Astronomy with ESO (FINCA), University of Turku, Finland (Academy of Finland grant nr 306531). S. Kang, S.-S. Lee, W. Y. Cheong, S.-H. Kim, and H.- W. Jeong were supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MIST) (2020R1A2C2009003, RS-2025- 00562700). CC acknowledges support by the European Research Council (ERC) under the HORIZON ERC Grants 2021 programme under grant agreement No. 101040021. This work was supported by JST, the establishment of university fellowships towards the creation of science technology innovation, Grant Number JPMJFS2129. D.B. acknowledge support from the European Research Council (ERC) under the European Unions Horizon 2020 research and innovation program under grant agreement No. 771282. J.O.-S. acknowledges founding from the Istituto Nazionale di Fisica Nucleare (INFN) Cap. U.1.01.01.01.009.https://www.aanda.org/10.1051/0004-6361/20255474
OBBA Impacts, County as Energy Supplier, Trayon White wins
No full textThe weekly news analysis from I Hate Politics: One Big Beautiful Act impacts with MD Delegate Marc Korman and MD Health Care for All Executive Director Vincent DeMarco: “Could have been worse!” Fall General Assembly Special Session now unlikely. Montgomery County Council considers pilot to become a retail energy supplier to residents. MD Delegate Lorig Charkoudian explains the concept. MoCo Council will vote on a law to allow duplexes/triplexes in single-family-zoned areas. Trayon White wins the DC Ward 8 Special Elections despite pending bribery charges. Analysis from once-Ward 8 candidate Markus Batchelor. Music by Washington DC art-pop rock band, Catscan!https://open.spotify.com/episode/2CzfLJksCTuSHv7gEPnxK
All-optical azimuthal trapping of dissipative Kerr multi-solitons for relative noise suppression
No full textTemporal cavity solitons, or dissipative Kerr solitons (DKSs) in integrated microresonators, are essential for deployable metrology technologies. Such applications favor the lowest noise state, typically the single-DKS state where one soliton is in the resonator. Other multi-DKS states can also be reached, offering better conversion efficiency and thermal stability, potentially simplifying DKS-based technologies. Yet they exhibit more noise due to relative soliton jitter and are usually not compatible with targeted applications. We demonstrate that Kerr-induced synchronization, an all-optical trapping technique, can azimuthally pin the multi-DKS state to a common reference field. This method ensures repetition rate noise is independent of the number of solitons, making a multi-DKS state indistinguishable from a single-DKS state in that regard, akin to trapped-soliton molecule behavior. Supported by theoretical analysis and experimental demonstration in an integrated microresonator, this approach provides metrological capacity regardless of the number of cavity solitons, benefiting numerous DKS-based metrology applications.S.C.O., K.S., and G.M. acknowledge the partial funding support from the Space Vehicles Directorate of the Air Force Research Laboratory and the NIST-on-a-chip program of the National Institute of Standards and Technology. P.S. and C.M. acknowledge the support from the National Science Foundation (Grant No. ECCS-1807272), the Air Force Office of Scientific Research (Grant No. FA9550-20- 1-0357), and a collaborative agreement with the National Center for Manufacturing Sciences (Grant No. 2022138-142232) as a subaward from the US Department of Defense (Cooperative Agreement No. HQ0034-20-2-0007). M.E. acknowledges the financial support from the Marsden Fund of the Royal Society of New Zealand (Grant No. 23-UOA-071). G.M. thanks T.B.M.https://pubs.aip.org/aip/app/article/10/1/016104/3330155/All-optical-azimuthal-trapping-of-dissipative-Ker
Connecting scattering, monodromy, and MST's renormalized angular momentum for the Teukolsky equation in Kerr spacetime
No full textThe Teukolsky equation describes perturbations of Kerr spacetime and is central to the study of rotating black holes and gravitational waves. In the frequency domain, the Teukolsky equation separates into radial and angular ordinary differential equations. Mano, Suzuki, and Takasugi (MST) found semi-analytic solutions to the homogeneous radial Teukolsky equation in terms of series of analytic special functions. The MST expansions hinge on an auxiliary parameter known as the renormalized angular momentum ν, which one must calculate to ensure the convergence of these series solutions. In this work, we present a method for calculating ν via monodromy eigenvalues, which capture the behavior of ordinary differential equations and their solutions in the complex domain near their singular points. We directly relate the monodromy data of the radial Teukolsky equation to the parameter ν and provide a numerical scheme for calculating ν based on monodromy. With this method we evaluate ν in different regions of parameter space and analyze the numerical stability of this approach. We also highlight how, through ν, monodromy data are linked to scattering amplitudes for generic (linear) perturbations of Kerr spacetime.The material is based upon work supported by NASA under award number 80GSFC21M0002. This work was also supported by NSF Grant No. PHY-1806447 to the University of North Carolina–Chapel Hill. The author also thanks A.C. Ottiwell, B. Wardell, M. Casals, and C.R. Evans for useful discussions. This work makes use of the Black Hole Perturbation Toolkit.https://iopscience.iop.org/article/10.1088/1361-6382/adf0d
Time-Periodic Solutions for Hyperbolic-Parabolic Systems
No full textTime-periodic weak solutions for a coupled hyperbolic-parabolic system are obtained. A linear heat and wave equation are considered on two respective d-dimensional spatial domains that share a common (d − 1)-dimensional interface Γ. The system is only partially damped, leading to an indeterminate case for existing theory (Galdi et al., 2014). We construct periodic solutions by obtaining novel a priori estimates for the coupled system, reconstructing the total energy via the interface Γ. As a byproduct, geometric constraints manifest on the wave domain which are reminiscent of classical boundary control conditions for wave stabilizability. We note a “loss” of regularity between the forcing and solution which is greater than that associated with the heat-wave Cauchy problem. However, we consider a broader class of spatial domains and mitigate this regularity loss by trading time and space differentiations, a feature unique to the periodic setting. This seems to be the first constructive result addressing existence and uniqueness of periodic solutions in the heat-wave context, where no dissipation is present in the wave interior. Our results speak to the open problem of the (non-)emergence of resonance in complex systems, and are readily generalizable to related systems and certain nonlinear cases.http://arxiv.org/abs/2412.1880