7 research outputs found
Incorporating Uncertainties in Atomic Data Into the Analysis of Solar and Stellar Observations: A Case Study in Fe XIII
Information about the physical properties of astrophysical objects cannot be
measured directly but is inferred by interpreting spectroscopic observations in
the context of atomic physics calculations. Ratios of emission lines, for
example, can be used to infer the electron density of the emitting plasma.
Similarly, the relative intensities of emission lines formed over a wide range
of temperatures yield information on the temperature structure. A critical
component of this analysis is understanding how uncertainties in the underlying
atomic physics propagates to the uncertainties in the inferred plasma
parameters. At present, however, atomic physics databases do not include
uncertainties on the atomic parameters and there is no established methodology
for using them even if they did. In this paper we develop simple models for the
uncertainties in the collision strengths and decay rates for Fe XIII and apply
them to the interpretation of density sensitive lines observed with the EUV
Imagining spectrometer (EIS) on Hinode. We incorporate these uncertainties in a
Bayesian framework. We consider both a pragmatic Bayesian method where the
atomic physics information is unaffected by the observed data, and a fully
Bayesian method where the data can be used to probe the physics. The former
generally increases the uncertainty in the inferred density by about a factor
of 5 compared with models that incorporate only statistical uncertainties. The
latter reduces the uncertainties on the inferred densities, but identifies
areas of possible systematic problems with either the atomic physics or the
observed intensities.Comment: in press at Ap
CALIPSO Mission Status Update: Payload Status
The CALIPSO mission payload status update is presented. The contents include: 1) Wide Field Camera Overview; 2) WFC Temperatures; 3) WFC Voltages; 4) Imaging Infrared Radiometer (IIR) Health; 5) IIR Voltages; 6) Payload Control (PLC) Voltages; 7) PLC Temperatures; 8) Low Voltage Power Supply (LVPS) (CALOPS0025N); 9) PLC Radiation Effects; 10) SDS Status (CALOPS0020N); 11) CALIOP LIDAR; 12) Laser Energy Trends; 13) Laser Energy Zoom; 14) Laser Management Approach; 15) Green / Red Ratio; 16) Pedestal @ SHG Temperature Trends; 17) LOM Heater Duty Cycle Trends; 18) LOM Pressure Trends; 19) Boresight Trend; 20) 1064 Dark Noise Trend; 21) 532 SNR Trend; 22) Spike Trends; 23) LIDAR Highlights; 24) Backup Laser Status; and 25) Future Plans
Earth Science With the Stratospheric Aerosol and Gas Experiment III (SAGE III) on the International Space Station
The Stratospheric Aerosol and Gas Experiment (SAGE) III is the fourth generation of solar occultation instruments operated by NASA, the first coming under a different acronym, to investigate the Earth's upper atmosphere. Three flight-ready SAGE III instruments were built by Ball Aerospace in the late 1990s, with one launched aboard the former Russian Aviation and Space Agency (now known as Roskosmos) Meteor-3M platform on 10 December 2001 (continuing until the platform lost power in 2006). Another of the original instruments was manifested for the ISS in the 2004 time frame, but was delayed because of budgetary considerations. Fortunately, that SAGE III/ISS mission was restarted in 2009 with a major focus upon filling an anticipated gap in ozone and aerosol observation in the second half of this decade. Here we discuss the mission architecture, its implementation, and data that will be produced by SAGE III/ISS, including their expected accuracy and coverage. The 52-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with excellent coverage of low and mid-latitudes. This is similar to that of the SAGE II mission (1985-2005), whose data set has served the international atmospheric science community as a standard for stratospheric ozone and aerosol measurements. The nominal science products include vertical profiles of trace gases, such as ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Though in the visible portion of the spectrum the brightness of the Sun is one million times that of the full Moon, the SAGE III instrument is designed to cover this large dynamic range and also perform lunar occultations on a routine basis to augment the solar products. The standard lunar products were demonstrated during the SAGE III/M3M mission and include ozone, nitrogen dioxide & nitrogen trioxide. The operational flexibility of the SAGE III spectrometer accomplishes the main goal of producing ozone and aerosol extinction profiles, while allowing exploration of new possibilities for the occultation technique, such as night-time aerosol extinction profiles or other trace gases not measured by SAGE in the past
The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when using real data, relative method performance is assessed using the total and nightly scatter of returned RVs and agreement between the results of different methods. Nearly all submitted methods return a lower RV rms than classic linear decorrelation, but no method is yet consistently reducing the RV rms to sub-meter-per-second levels. There is a concerning lack of agreement between the RVs returned by different methods. These results suggest that continued progress in this field necessitates increased interpretability of methods, high-cadence data to capture stellar signals at all timescales, and continued tests like the ESSP using consistent data sets with more advanced metrics for method performance. Future comparisons should make use of various well-characterized data sets—such as solar data or data with known injected planetary and/or stellar signals—to better understand method performance and whether planetary signals are preserved
Essential pharmacologic options for acute pain management in the emergency setting
Pain is the root cause for the overwhelming majority of emergency department (ED) visits worldwide. However, pain is often undertreated due to inappropriate analgesic dosing and ineffective utilization of available analgesics. It is essential for emergency providers to understand the analgesic armamentarium at their disposal and how it can be used safely and effectively to treat pain of every proportion within the emergency setting. A ‘balanced analgesia’ regimen may be used to treat pain while reducing the overall pharmacologic side effect profile of the combined analgesics. Channels-Enzymes-Receptors Targeted Analgesia (CERTA) is a multimodal analgesic strategy incorporating balanced analgesia by shifting from a system-based to a mechanistic-based approach to pain management that targets the physiologic pathways involved in pain signaling transmission. Targeting individual pain pathways allows for a variety of reduced-dose pharmacologic options – both opioid and non-opioid – to be used in a stepwise progression of analgesic strength as pain advances up the severity scale. By developing a familiarity with the various analgesic options at their disposal, emergency providers may formulate safe, effective, balanced analgesic combinations unique to each emergency pain presentation. Keywords: Pain management, Balanced analgesia, CERTA, Opioids, Non-opioids, Emergency medicin
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The EXPRES Stellar Signals Project II. State of the Field in Disentangling Photospheric Velocities
Abstract: Measured spectral shifts due to intrinsic stellar variability (e.g., pulsations, granulation) and activity (e.g., spots, plages) are the largest source of error for extreme-precision radial-velocity (EPRV) exoplanet detection. Several methods are designed to disentangle stellar signals from true center-of-mass shifts due to planets. The Extreme-precision Spectrograph (EXPRES) Stellar Signals Project (ESSP) presents a self-consistent comparison of 22 different methods tested on the same extreme-precision spectroscopic data from EXPRES. Methods derived new activity indicators, constructed models for mapping an indicator to the needed radial-velocity (RV) correction, or separated out shape- and shift-driven RV components. Since no ground truth is known when using real data, relative method performance is assessed using the total and nightly scatter of returned RVs and agreement between the results of different methods. Nearly all submitted methods return a lower RV rms than classic linear decorrelation, but no method is yet consistently reducing the RV rms to sub-meter-per-second levels. There is a concerning lack of agreement between the RVs returned by different methods. These results suggest that continued progress in this field necessitates increased interpretability of methods, high-cadence data to capture stellar signals at all timescales, and continued tests like the ESSP using consistent data sets with more advanced metrics for method performance. Future comparisons should make use of various well-characterized data sets—such as solar data or data with known injected planetary and/or stellar signals—to better understand method performance and whether planetary signals are preserved