1,633 research outputs found

    The Evolving Role of Economic Analysis In SEC Rulemaking

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    Recently, the SEC has come under great scrutiny for how it conducts economic analysis around rulemakings, especially those associated with the Dodd-Frank Wall Street Reform and Consumer Protection Act (Dodd-Frank or the Dodd-Frank Act) Dodd-Frank tasked the SEC with more than 100 rulemaking provisions. Perhaps no criticism had a more profound effect than the D.C. Circuit\u27s decision in Business Roundtable v. SEC, which struck down the SEC\u27s proxy access rule due to inadequate economic analysis. Regulations are imperfect. They cannot be costlessly executed or enforced. Regulators also lack full information on the actual costs and benefits of proposed policies. For the Securities and Exchange Commission (SEC or Commission), scholars note that the costs and benefits of proposed actions are especially difficult to generate because their rules frequently involve disclosure6 or a probabilistic prediction of future risky events. These challenges indicate that the SEC will sometimes misestimate quantified values of costs and benefits

    Multiple Network Embedding for Anomaly Detection in Time Series of Graphs

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    This paper considers the graph signal processing problem of anomaly detection in time series of graphs. We examine two related, complementary inference tasks: the detection of anomalous graphs within a time series, and the detection of temporally anomalous vertices. We approach these tasks via the adaptation of statistically principled methods for joint graph inference, specifically multiple adjacency spectral embedding (MASE) and omnibus embedding (OMNI). We demonstrate that these two methods are effective for our inference tasks. Moreover, we assess the performance of these methods in terms of the underlying nature of detectable anomalies. Our results delineate the relative strengths and limitations of these procedures, and provide insight into their use. Applied to a large-scale commercial search engine time series of graphs, our approaches demonstrate their applicability and identify the anomalous vertices beyond just large degree change.Comment: 22 pages, 11 figure

    Influence of the Fermi Surface Morphology on the Magnetic Field-Driven Vortex Lattice Structure Transitions in YBa2_{2}Cu3_{3}O7−δ:δ=_{7-\delta}:\delta=0, 0.15

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    We report small-angle neutron scattering measurements of the vortex lattice (VL) structure in single crystals of the lightly underdoped cuprate superconductor YBa2Cu3O6.85. At 2 K, and for fields of up to 16 T applied parallel to the crystal c-axis, we observe a sequence of field-driven and first-order transitions between different VL structures. By rotating the field away from the c-axis, we observe each structure transition to shift to either higher or lower field dependent on whether the field is rotated towards the [100] or [010] direction. We use this latter observation to argue that the Fermi surface morphology must play a key role in the mechanisms that drive the VL structure transitions. Furthermore, we show this interpretation is compatible with analogous results obtained previously on lightly overdoped YBa2Cu3O7. In that material, it has long-been suggested that the high field VL structure transition is driven by the nodal gap anisotropy. In contrast, the results and discussion presented here bring into question the role, if any, of a nodal gap anisotropy on the VL structure transitions in both YBa2Cu3O6.85 and YBa2Cu3O7

    Structural and phase evolution in U₃Si₂ during steam corrosion

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    U₃Si₂ nuclear fuel is corroded in deuterated steam with in situ neutron diffraction. Density functional theory is coupled with rigorous thermodynamic description of the hydride including gas/solid entropy contributions. H absorbs in the 2b interstitial site of U₃Si₂Hx and moves to 8j for x ≥ 0.5. Hydriding forces lattice expansion and change in a/c ratio linked to site preference. Rietveld refinement tracks the corrosion reactions at 350-500 °C and preference for the 8j site. Above 375 °C, formation of UO₂, U₃Si₅ and USi₃ take place in the grain boundaries and bulk. Hydriding occurs in bulk and precedes other reactions

    Drug Combinations as a First Line of Defense against Coronaviruses and Other Emerging Viruses

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    The world was unprepared for coronavirus disease 2019 (COVID-19) and remains ill-equipped for future pandemics. While unprecedented strides have been made developing vaccines and treatments for COVID-19, there remains a need for highly effective and widely available regimens for ambulatory use for novel coronaviruses and other viral pathogens. We posit that a priority is to develop pan-family drug cocktails to enhance potency, limit toxicity, and avoid drug resistance. We urge cocktail development for all viruses with pandemic potential both in the short term (Peer reviewe

    Enhanced surface passivation of sub-nanometer silicon dioxide films by superacidic treatments

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    Subnanometer-scale silicon dioxide (SiO2) films are frequently present before, during, and after silicon device processing, yet they offer minimal surface passivation and can detrimentally impact subsequent processing steps. Here we develop a process whereby the surface passivation of nanometer and subnanometer SiO2 films is enhanced by up to 2 orders of magnitude by a simple room temperature treatment using the superacid bis(trifluoromethane)sulfonimide (TFSA, sometimes TFSI). By accurately modeling the effective lifetime curves corresponding to the superacid treated SiO2 samples, we have determined that the enhanced passivation is mainly due to a reduction in the interface defect density (Dit) at the Si/SiO2 interface, with a minor contribution also arising from the presence of negative charge. X-ray photoelectron spectroscopy of the treated SiO2 films reveals the presence of fluorine, and this, along with hydrogen, is a strong candidate for the chemical passivation of defects at the Si/SiO2 interface. Post treatment, the SiO2 films show short time scale electronic instability, whereby a degradation and then recovery are observed over a period of 1–10 h which is attributed to variations in the Dit, as determined from our analysis of the injection-dependent lifetime data. Following the instability period, the surface passivation remains relatively stable for days. Nuclear magnetic resonance measurements of superacid-based solutions reveal that electron-donating solvents should be avoided, as they exacerbate surface passivation instabilities. The results presented demonstrate that simple strategies can be used to enhance the passivation properties of ultrathin films greatly, which in the age of nanotechnology could offer benefits to device performance in a range of applications including solar cells and batteries

    Combinations of Host- and Virus-Targeting Antiviral Drugs Confer Synergistic Suppression of SARS-CoV-2

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    Three directly acting antivirals (DAAs) demonstrated substantial reduction in COVID-19 hospitalizations and deaths in clinical trials. However, these agents did not completely prevent severe illness and are associated with cases of rebound illness and viral shedding. Combination regimens can enhance antiviral potency, reduce the emergence of drug-resistant variants, and lower the dose of each component in the combination. Concurrently targeting virus entry and virus replication offers opportunities to discover synergistic drug combinations. While combination antiviral drug treatments are standard for chronic RNA virus infections, no antiviral combination therapy has been approved for SARS-CoV-2. Here, we demonstrate that combining host-targeting antivirals (HTAs) that target TMPRSS2 and hence SARS-CoV-2 entry, with the DAA molnupiravir, which targets SARS-CoV-2 replication, synergistically suppresses SARS-CoV-2 infection in Calu-3 lung epithelial cells. Strong synergy was observed when molnupiravir, an oral drug, was combined with three TMPRSS2 (HTA) oral or inhaled inhibitors: camostat, avoralstat, or nafamostat. The combination of camostat plus molnupiravir was also effective against the beta and delta variants of concern. The pyrimidine biosynthesis inhibitor brequinar combined with molnupiravir also conferred robust synergistic inhibition. These HTA+DAA combinations had similar potency to the synergistic all-DAA combination of molnupiravir plus nirmatrelvir, the protease inhibitor found in paxlovid. Pharmacodynamic modeling allowed estimates of antiviral potency at all possible concentrations of each agent within plausible therapeutic ranges, suggesting possible in vivo efficacy. The triple combination of camostat, brequinar, and molnupiravir further increased antiviral potency. These findings support the development of HTA+DAA combinations for pandemic response and preparedness. IMPORTANCE Imagine a future viral pandemic where if you test positive for the new virus, you can quickly take some medicines at home for a few days so that you do not get too sick. To date, only single drugs have been approved for outpatient use against SARS-CoV-2, and we are learning that these have some limitations and may succumb to drug resistance. Here, we show that combinations of two oral drugs are better than the single ones in blocking SARS-CoV-2, and we use mathematical modeling to show that these drug combinations are likely to work in people. We also show that a combination of three oral drugs works even better at eradicating the virus. Our findings therefore bode well for the development of oral drug cocktails for at home use at the first sign of an infection by a coronavirus or other emerging viral pathogens.Peer reviewe

    SDSS J092455.87+021924.9: an Interesting Gravitationally Lensed Quasar from the Sloan Digital Sky Survey

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    We report the discovery of a new gravitationally lensed quasar from the Sloan Digital Sky Survey, SDSS J092455.87+021924.9 (SDSS J0924+0219). This object was selected from among known SDSS quasars by an algorithm that was designed to select another known SDSS lensed quasar (SDSS 1226-0006A,B). Five separate components, three of which are unresolved, are identified in photometric follow-up observations obtained with the Magellan Consortium's 6.5m Walter Baade telescope at Las Campanas Observatory. Two of the unresolved components (designated A and B) are confirmed to be quasars with z=1.524; the velocity difference is less than 100 km sec^{-1} according to spectra taken with the W. M. Keck Observatory's Keck II telescope on Mauna Kea. A third stellar component, designated C, has the colors of a quasar with redshift similar to components A and B. The maximum separation of the point sources is 1.78". The other two sources, designated G and D, are resolved. Component G appears to be the best candidate for the lensing galaxy. Although component D is near the expected position of the fourth lensed component in a four image lens system, its properties are not consistent with being the image of a quasar at z~1.5. Nevertheless, the identical redshifts of components A and B and the presence of component C strongly suggest that this object is a gravitational lens. Our observations support the idea that a foreground object reddens the fourth lensed component and that another unmodeled effect (such as micro- or milli-lensing) demagnificates it, but we cannot rule out the possibility that SDSS0924+0219 is an example of the relatively rare class of ``three component'' lens systems.Comment: 24 pages, 6 figures, accepted by A
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