Examining a Peak-Luminosity/Decline-Rate Relationship for Tidal Disruption Events

We compare the luminosity, radius, and temperature evolution of the UV/optical blackbodies for 21 well-observed tidal disruption events (TDEs), 8 of which were discovered by the All-Sky Automated Survey for Supernovae. We find that the blackbody radii generally increase prior to peak and slowly decline at late times. The blackbody temperature evolution is generally flat, with a few objects showing small-scale variations. The bolometric UV/optical luminosities generally evolve smoothly and flatten out at late times. Finally, we find an apparent correlation between the peak luminosity and the decline rate of TDEs. This relationship is strongest when comparing the peak luminosity to its decline over 40 days. A linear fit yields $\log_{10}( L_{peak}) = (44.1^{+0.1}_{-0.1}) + (1.6^{+0.4}_{-0.2})(\Delta L_{40} + 0.5)$ in cgs, where $\Delta L_{40} = \log_{10}(L_{40} / L_{peak})$.Comment: 10 pages, 4 figures. Updated to reflect changes made in the published ApJL version. Six new objects added to sample. Updated video description can be found at https://youtu.be/TtZU22eyHv

Evidence-Based Background Material Underlying Guidance for Federal Agencies in Implementing Strategic Sustainability Performance Plans - Implementing Sustainability: The Institutional-Behavioral Dimension

This document is part of a larger, programmatic effort to assist federal agencies in taking action and changing their institutions to achieve and maintain federal sustainability goals, while meeting their mission goals. FEMP is developing guidance for federal agency efforts to enable institutional behavior change for sustainability, and for making sustainability “business as usual.” The driving requirement for this change is Executive Order (EO) 13514, Federal Leadership in Environmental, Energy, and Economic Performance. FEMP emphasizes strategies for increasing energy efficiency and renewable energy utilization as critical components of attaining sustainability, and promotes additional non-energy action pathways contained in EO 13514. This report contributes to the larger goal by laying out the conceptual and evidentiary underpinnings of guidance to federal agencies. Conceptual frameworks focus and organize the development of guidance. We outline a series of progressively refined conceptual frameworks, including a multi-layer approach, key steps in sustainability implementation, a process view of specific approaches to institutional change, the agency Strategic Sustainability Performance Plans (SSPPs), and concepts related to context-specific rules, roles and tools for sustainability. Additionally, we tap pertinent bodies of literature in drawing eight evidence-based principles for behavior change. These principles are important foundations upon which to build in selecting strategies to effect change in organizations. Taken together, this report presents a suite of components that inform the training materials, presentations, web site, and other products that provide guidance to federal agencies

Chandra, HST/STIS, NICER, Swift, and TESS Detail the Flare Evolution of the Repeating Nuclear Transient ASASSN-14ko

ASASSN-14ko is a nuclear transient at the center of the AGN ESO 253-G003 that undergoes periodic flares. Optical flares were first observed in 2014 by the All-Sky Automated Survey for Supernovae (ASAS-SN) and their peak times are well-modeled with a period of $115.2^{+1.3}_{-1.2}$ days and period derivative of $-0.0026 \pm 0.0006$. Here we present ASAS-SN, Chandra, HST/STIS, NICER, Swift, and TESS data for the flares that occurred in December 2020, April 2021, July 2021, and November 2021. The HST/STIS UV spectra evolve from blue shifted broad absorption features to red shifted broad emission features over $\sim$10 days. The Swift UV/optical light curves peaked as predicted by the timing model, but the peak UV luminosities varied between flares and the UV flux in July 2021 was roughly half the brightness of all other peaks. The X-ray luminosities consistently decreased and the spectra became harder during the UV/optical rise but apparently without changes in absorption. Finally, two high-cadence TESS light curves from December 2020 and November 2018 showed that the slopes during the rising and declining phases changed over time, which indicates some stochasticity in the flare's driving mechanism. ASASSN-14ko remains observationally consistent with a repeating partial tidal disruption event, but, these rich multi-wavelength data are in need of a detailed theoretical model.Comment: 25 pages, 14 figures, 4 tables; Submitted to ApJ, comments welcom

Towards soft wearable strain sensors for muscle activity monitoring

The force-generating capacity of skeletal muscle is an important metric in the evaluation and diagnosis of musculoskeletal health. Measuring changes in muscle force exertion is essential for tracking the progress of athletes during training, for evaluating patients’ recovery after muscle injury, and also for assisting the diagnosis of conditions such as muscular dystrophy, multiple sclerosis, or Parkinson’s disease. Traditional hardware for strength evaluation requires technical training for operation, generates discrete time points for muscle assessment, and is implemented in controlled settings. The ability to continuously monitor muscle force without restricting the range of motion or adapting the exercise protocol to suit specific hardware would allow for a richer dataset that can help unlock critical features of muscle health and strength evaluation. In this paper, we employ wearable, ultra-sensitive soft strain sensors for tracking changes in muscle deformation during contractions. We demonstrate the sensors’ sensitivity to isometric contractions, as well as the sensors’ capacity to track changes in peak torque over the course of an isokinetic fatiguing protocol for the knee extensors. The wearable soft system was able to efficiently estimate peak joint torque reduction caused by muscle fatigue (mean NRMSE =0.15±0.03 )

Murine Pancreatic Adenocarcinoma Reduces Ikaros Expression and Disrupts T Cell Homeostasis

Background Maintenance of T cell immune homeostasis is critical for adequate anti-tumor immunity. The transcription factor Ikaros is essential for lymphocyte development including T cells. Alterations in Ikaros expression occur in blood malignancies in humans and mice. In this study, we investigated the role of Ikaros in regulating T cell immune balance in pancreatic cancer mouse models. Methodology and Principal Findings Using our Panc02 tumor-bearing (TB) mouse model, western blot analysis revealed a reduction in Ikaros proteins while qRT-PCR showed no differences in Ikaros mRNA levels in TB splenocytes compared to control. Treatment of naïve splenocytes with the proteasomal inhibitor, MG132, stabilized Ikaros expression and prevented Ikaros downregulation by Panc02 cells, in vitro. Western blot analyses showed a reduction in protein phosphatase 1 (PP1) and protein kinase CK2 expression in TB splenocytes while CK2 activity was increased. Immunofluorescence microscopy revealed altered punctate staining of Ikaros in TB splenocytes. Flow cytometry revealed a significant decrease in effector CD4+ and CD8+ T cell percentages but increased CD4+CD25+ regulatory T cells in TB splenocytes. Similar alterations in T cell percentages, as well as reduced Ikaros and CK2 but not PP1 expression, were observed in a transgenic, triple mutant (TrM) pancreatic cancer model. Ikaros expression was also reduced in enriched TB CD3+ T cells. MG132 treatment of naïve CD3+ T cells stabilized Ikaros expression in the presence of Panc02 cells. Western blots showed reduced PP1 and CK2 expression in TB CD3+ T cells. Conclusions/Significance The results of this study suggest that the pancreatic tumor microenvironment may cause proteasomal degradation of Ikaros, possibly via dysregulation of PP1 and CK2 expression and activity, respectively. This loss of Ikaros expression may contribute to an imbalance in T cell percentages. Ikaros may potentially be a therapeutic target to restore T cell homeostasis in pancreatic cancer hosts, which may be critical for effective anti-tumor immunity

An AMUSING look at the host of the periodic nuclear transient ASASSN-14ko reveals a second AGN

We present Multi-Unit Spectroscopic Explorer (MUSE) integral-field spectroscopy of ESO 253-G003, which hosts a known active galactic nucleus (AGN) and the periodic nuclear transient ASASSN-14ko, observed as part of the All-weather MUse Supernova Integral-field of Nearby Galaxies survey. The MUSE observations reveal that the inner region hosts two AGN separated by 1.4±0.1 kpc (≍1 ′′. 7). The brighter nucleus has asymmetric broad permitted emission-line profiles and is associated with the archival AGN designation. The fainter nucleus does not have a broad emission-line component but exhibits other AGN characteristics, including vFWHM≈700 km~s−1 forbidden line emission, log10([OIII]/Hβ)≈1.1 , and high-excitation potential emission lines, such as [Fe VII] λ6086 and He II λ4686. The host galaxy exhibits a disturbed morphology with large kpc-scale tidal features, potential outflows from both nuclei, and a likely superbubble. A circular relativistic disc model cannot reproduce the asymmetric broad emission-line profiles in the brighter nucleus, but two non-axisymmetric disc models provide good fits to the broad emission-line profiles: an elliptical disc model and a circular disc + spiral arm model. Implications for the periodic nuclear transient ASASSN-14ko are discussed.MAT acknowledges support from the DOE CSGF through grant no. DE-SC0019323. BJS and CSK are supported by NSF grant no. AST-1907570. BJS is also supported by NASA grant no. 80NSSC19K1717 and NSF grants AST-1920392 and AST-1911074. CSK is supported by NSF grant no. AST-181440. KAA is supported by the Danish National Research Foundation (DNRF132). Support for JLP is provided in part by FONDECYT through grant n.1191038 and by the Ministry for the Economy, Development, and Tourism’s Millennium Science Initiative through grant no. IC120009, awarded to The Millennium Institute of Astrophysics, MAS. LG acknowledges financial support from the Spanish Ministry of Science, Innovation and Universities (MICIU) under the 2019 Ramón y Cajal program RYC2019-027683 and from the Spanish MICIU project PID2020-115253GA-I00. Parts of this research were supported by the Australian Research Council Centre of Excellence for All Sky Astrophysics in 3 Dimensions (ASTRO 3D), through project number CE170100013. LG was funded by the European Union’s Horizon 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No. 839090, and partially supported by the Spanish grant no. PGC2018-095317-B-C21 within the European Funds for Regional Development (FEDER). Support for TW-SH was provided by NASA through the NASA Hubble Fellowship grant no. #HST-HF2-51458.001-A awarded by the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., for NASA, under contract NAS5-26555. Based on observations collected at the European Organization for Astronomical Research in the Southern Hemisphere under ESO programme 096.D-0296(A).Peer reviewe