Atmospheric Beacons of Life from Exoplanets Around G and K Stars OPEN
Published: xx xx xxxx

Vladimir S Airapetian
American University
WashingtonDCUSA

Charles H Jackman
Martin Mlynczak
American University
WashingtonDCUSA

William Danchi
Linda Hunt
NASA/LARC
HamptonVAUSA

GreenbeltMDUSA

Atmospheric Beacons of Life from Exoplanets Around G and K Stars OPEN

Scientific RepoRts |
714141Published: xx xx xxxx10.1038/s41598-017-14192-4Received: 7 April 2017 Accepted: 6 October 20171 4 SSAI, Hampton, VA, USA. Correspondence and requests for materials should be addressed to V.S.A. (email: vladimir. firstname.lastname@example.com)
The current explosion in detection and characterization of thousands of extrasolar planets from the Kepler mission, the Hubble Space Telescope, and large ground-based telescopes opens a new era in searches for Earth-analog exoplanets with conditions suitable for sustaining life. As more Earth-sized exoplanets are detected in the near future, we will soon have an opportunity to identify habitale worlds. Which atmospheric biosignature gases from habitable planets can be detected with our current capabilities? The detection of the common biosignatures from nitrogen-oxygen rich terrestrial-type exoplanets including molecular oxygen (O 2 ), ozone (O 3 ), water vapor (H 2 O), carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ) requires days of integration time with largest space telescopes, and thus are very challenging for current instruments. In this paper we propose to use the powerful emission from rotational-vibrational bands of nitric oxide, hydroxyl and molecular oxygen as signatures of nitrogen, oxygen, and water rich atmospheres of terrestrial type exoplanets "highlighted" by the magnetic activity from young G and K main-sequence stars. The signals from these fundamental chemical prerequisites of life we call atmospheric "beacons of life" create a unique opportunity to perform direct imaging observations of Earth-sized exoplanets with high signal-to-noise and low spectral resolution with the upcoming NASA missions.Detection of signatures of life from remote exoplanetary systems is the ultimate goal of astrobiology. The signs of life known as "biosignatures" can potentially be retrieved through the impact of exoplanetary biospheres on atmospheric chemistry. The current methodologies for detecting observable signatures of life in terrestrial-type planets are based on the presence of chemical compounds that are out of chemical equilibrium due to the complex biochemistry of life 1,2 . Signatures of life should meet the criteria of reliability, survivability and detectability and can be identified with remote-sensing detection of the most common molecules in the Earth's troposphere, including molecular oxygen (O 2 ), ozone (O 3 ), water vapor (H 2 O), carbon dioxide (CO 2 ), nitrous oxide (N 2 O), and methane (CH 4 ), surface reflectance signatures or polarized scattering in exoplanetary atmospheres 3-6 . The presence of abundant atmospheric molecular oxygen may be a strong indicator of oxygenic photosynthesis, together with methane, the marker of biological decay, and other molecules suggest that the atmosphere is in chemical disequilibrium driven by biological activity 2-4 . However, abiotic production of molecular oxygen can be driven by the photolysis of CO 2 , H 2 O and other oxygen-bearing gases via UV and particle collisions in scenarios of terrestrial-type exoplanets around K, G or M dwarf stars 3,7-9 and could mimic a biologically driven oxygen production. Given this mechanism, the expected O 2 production for various scenarios is over 3 orders of magnitude smaller than that observed in current Earth 8 . The situation for very dry (water-depleted) CO 2 atmospheres of exoplanets around M dwarf stars is different; in this case O 2 can be produced abiotically at the level of Earth-like oxygen abundance 9 . Thus, the absence of water signatures in reflectance and emission spectra can serve as a potential indicator of the abiotic nature of atmospheric O 2 . In water-rich exoplanetary atmospheres, photolysis of atmospheric water vapor can also produce an accumulation of oxygen due to the thermal escape of hydrogen under some scenarios for exoplanets around active stars 10 . However, the production and accumulation of oxygen could be prevented for terrestrial exoplanets located in the highly compact habitable zones around active M dwarfs. Stellar activity from these host stars can create intense X-ray and Extreme-UV (XUV) emission and magnetized winds, which are the major factors contributing to the non-thermal ionospheric escape of oxygen ions (along with hydrogen)11.In general, the abundance of atmospheric molecular oxygen can vary in response of the planetary environments influenced by the fraction of land mass versus ocean mass, volcanic and tectonic activity and the efficiency 1 NASA/GSFC,

of atmospheric escape mediated by the activity from the host star [11][12][13] . Abiotic production of another important biosignature gas, methane, is not an efficient process as compared to its biological origin due to bacteria and biological decay processes, thus making its presence together with molecular oxygen a strong biosignature 14 . However, the current biological production of methane in the Earth's troposphere and stratosphere is mostly due to anthropogenic sources and is ~1.8 ppmv. The major biosignature gases from an Earth-like "living" planet around a Sun-like star are difficult to detect with current telescopes and require long exposures with high spectral, high contrast, and high spatial resolution coronographic instruments on ground-based telescopes such as the Giant-Magellan Telescope (GMT), the Ten Meter Telescope (TMT), the European Extremely Large Telescope E-ELT, and space-based telescopes such as the Habitable Explorere (HabEx), the Large UV Optical and Infrared (LUVOIR), and the Origins Space Telescope (OST) 15,16 .

In this paper we propose that strong non-thermal emission from broad molecular bands in the near-and mid-infrared (mid-IR) referred to as "beacons of life" can be emitted by molecular products of nitrogen-and oxygen-rich exoplanetary atmospheres with high (a large fraction of 1 bar) atmospheric pressures. These include stellar activity driven emission from nitric oxide, hydroxyl and oxygen molecules as the strongest signals that may be observable from the habitable worlds.

Results

Atmospheric "Beacons of Life" from Earth. Life as we know it requires, but is not limited to, a nitrogen-rich atmosphere with the presence of abundant free oxygen produced by photosynthesis and the presence of liquid water. Molecular nitrogen (N 2 ) is the dominant gas in the Earth's atmosphere, because of its geochemical stability. The high abundance of atmospheric N 2 was critical for the initiation of life on the early Earth, because fixation of nitrogen is required to create linkages of long chained molecules including proteins and base pairs of RNA and DNA 7,17 . Nitric oxide (NO) and hydroxyl (OH) are efficiently produced in the thermosphere as a result of photo-dissociation (X-ray and EUV) and collisional dissociation (via precipitating electrons) of molecular nitrogen and water vapor (see R1-R * in METHODS). The abundance of NO during quiet times (no geomagnetic storms) varies within a few ppbv and increases by a factor of 100 during strong geomagnetic storms induced by coronal mass ejections from the Sun 18,19 . The abundances of NO, OH and O 2 are traced by observations of time-varying emission from molecular bands of NO at 5.3-µm, OH at 1.6 and 2 µm and O 2 ( 1 Δ) at 1.27 µm. NO emission from the 5.3-µm band is created by a large number of vibration-rotation transitions excited by inelastic collisions with atomic and molecular oxygen 19,20 and exothermic reactions. Observations made over the last 15 years with the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument aboard NASA's TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite have revealed that the emitting power of NO is strongly correlated with the solar activity cycle traced by the solar radio flux at 10.7 cm, the indicator of solar activity as well as the indices that trace the strength of Coronal Mass Ejection (CME) induced geomagnetic storms. The total power emitted by thermospheric nitric oxide at 5.3 µm and carbon dioxide at 15 µm varies within ~100 GW reaching ~2 TW during strong geomagnetic storms comparable to the one that occurred on Oct 28-31, 2003. The Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) observations reveal an increase of NO abundance by a factor of 10 at the height range of 6-68 km during large Oct-Nov 2003 geomagnetic storm reaching a concentration over 300 ppbv at high lattitudes 20 . This caused the enhancement of the NO emission power by a factor of 20-30 in the mid-IR bands as compared to the atmospheric state during the quiet Sun at solar minimum 21 . The drastic enhancement of NO caused the depletion of ozone by up to 60% during the Oct -Nov 2003 storm as observed at high lattitudes at 50-60 km 20 .

The radiative power increase during geomagnetic storms is attributed to the enhancement of production of NO molecules and increased kinetic temperature. Infrared NO radiative cooling plays the role of an efficient thermostat by cooling the thermosphere in response to the radiative and non-radiative heating associated with space weather events 22,23 . NO radiative cooling becomes sharply enhanced (more than a factor of 10) due to the increased energy input into the ionosphere-thermosphere (IT) system of polar cap regions during geomagnetic storms. The non-radiative heating is introduced by resistive dissipation of ionospheric currents (Joule heating, JH) in response to the perturbation of the global magnetosphere caused by CME events, ion-neutral collisions and particle precipitation in the polar regions of the planet. If most of the energy entering the IT system is radiated away in the form of NO and CO 2 emission, then we can expect that its power should increase proportionally with the input energy flux. The XUV flare emission at wavelengths between 1-70 Å is another crucial source of production of low-latitude thermospheric NO driven by photoelectrons formed via photoionization of atmospheric species 23 .

The emission in OH bands (1.6 & 2 µm) observed by SABER has the total power of ~0.2 TW, which is weakly dependent on the solar cycle (see Fig. 1). Figure 2 presents the flux evolution of O 2 ( 1 Δ) emission flux at 1.27 µm during 2004 to 2008, which shows variations of emission power between zero (at night, increasing substantially in daytime due to O 3 photolysis via UV solar radiation) to 230 TW.

Beacons of Life from Exoplanets Around Active Stars. Recent Kepler Space Telescope and Hubble

Space Telescope data suggest that magnetically active main-sequence stars of K, G and M spectral types generate high XUV fluxes from magnetically driven flares with energies over 10 times greater than that of the current Sun 24,25 . As a result of the energy input, the Earth's thermosphere responds with enhanced radiative cooling from the molecular bands of NO at 5.3 µm, CO 2 at 15 µm as well as conductive cooling. Using scaling of NO emission power at 5.3 µm with the F10.7 flux, the proxy for the solar XUV flux, and Ap index, the measure of the geomagnetic activity, we can expect the enhancement of NO emission by over one order of magnitude 20 .

Low mass stars including K and M dwarfs are known to remain magnetically active and exhibit high XUV fluxes (over 10 times higher than that of the current Sun) over 2-3 Gyr. For example, XUV fluxes from "mature" 4-6 Gyr-old K and M main-sequence stars are by a factor of 10 greater than that of the Sun at the inner edge of their respective habitable zones 26 . This flux is comparable to the XUV flux from the young 0.7 Gyr-old Sun 7 . This persistent stellar magnetic activity may have a profound effect on the dynamics and chemistry of the early Earth and potential atmospheres of exoplanets around K-M stars 7,11 . Clues to the history of the atmospheric chemistry of the early Earth, specifically its oxygen abundance, come from geological (rock) records suggesting that our planet's atmosphere was weakly oxidizing with less than 0.001% of O 2 during the first half of our planet history including the time when life started on Earth. Only ~2.4 Gyr ago our atmosphere acquired appreciable concentration of free oxygen. This puzzling increase of O 2 is known as Great Oxidation Event (GOE) 27 . The GOE time scale is comparable or shorter than the magnetic evolution time scale for low mass cool stars. Can stellar activity control the onset of the GOE on terrestrial-type exoplanets? Oxygenated atmospheres of terrestrial type exoplanets can be created by several factors including atmospheric escape, surface gravity, and the magnetic activity of its host star. One of the factors causing the accumulation of atmospheric oxygen in the troposphere at ~2.4 Gyr ago could be XUV-driven photolysis of the carbon dioxide the low pressure (~0.25 bar) early Earth atmosphere  depleted due to XUV driven escape of oxygen and nitrogen ions 11,28 . This may suggest that the active low mass stars with greater XUV fluxes can induce comparable atmospheric erosion at shorter time scale causing O 2 accumulation earlier in the history of a terrestrial type exoplanet. Thus, in many scenarios terrestrial type exoplanets with N 2 -rich oxygenated atmospheres can be exposed to high energy fluxes from their host stars. XUV emission and energetic particles can be efficient in photodissociation of the atmospheric molecular nitrogen, carbon dioxide and water vapor resulted in production of nitric oxide and hydroxyl molecules 7,20,21 .

How would space weather from active stars in the form of XUV radiation and SEP particle fluxes affect the amount of NO and OH emission in the mid-IR bands that would be expected from oxygen-rich terrestrial-type exoplanets around active G, K and M stars? To investigate the atmospheric chemistry changes owing to CME driven solar energetic particles (SEPs), we expose an Earth-like oxygen-rich atmposphere to the energy fluxes expected from active G, K and M main-sequence stars. We computed a grid of 5 atmospheric chemistry models of an Earth twin to numerically study the chemical evolution of nitrogen oxides, NO x (N, NO, NO 2 ) HO x (H, OH and HO 2 ) constituents and ozone in response to various fluxes of energetic protons during SEPs in the stratosphere and themosphere. For this purpose, we used the two-dimensional photochemical transport Goddard Space Flight Center (GSFC) atmospheric model that calculates the constituents in the upper stratosphere (35 km) extending to the upper mesosphere (95 km) (see METHODS). Our study includes the base model (base Model A, no SEP and the current XUV flux, F 0 ), Model B (no SEP and XUV flux at 10F 0 ), Model C (July 2000 SEP event and XUV flux at 10F 0 ), Model D (10 × July 2000 SEP event and XUV flux at 10F 0 ), Model E (20 × July 2000 SEP event and XUV flux at 10F 0 ). We used the maximum daily average particle input for the SEP event, which occurred on July 15, 2000, that was associated with the fast (1800 km/s) halo CME and the Bastille Day × 5.7 solar flare 29 .

Our simulations suggest that at the atmospheric height range between 0 to 95 km, the enhanced XUV flux from the Sun is not efficient in the production of odd nitrogen, and thus only modest changes in NO mixing ratio are observed. Model B (no SEP and the active Sun at 10F 0 ) shows NO values of typically 1 ppbv at 80-90 km (the left panel of Fig. 3), which are similar to those computed for base Model A. The steady state energy flux in the form of energetic protons from 1-300 MeV with the energy spectrum and intensity characteristic of the July 2000 SEP event (Model C, see also Methods) produces a mixing ratio for NO that is enhanced by a factor of 200 (or 200 ppbv at the reference height of 85 km) in the polar cap regions (the middle panel of Fig. 3) with respect to the quiet conditions described by Model B. Model D suggests that NO net production increases approximately linearly in response to the enhancement of the intensity of the proton flux by a factor of 10 with respect to Model C, and reaches 2 ppmv (the right panel of Fig. 3). These fluxes are consistent with the results of 1D atmospheric models applied for SEP driven atmospheric chemistry of exoplanets around M dwarfs 30 . Such large concentrations of NO from an oxygen-rich atmosphere are by a factor of 10-30 greater than than modeled in the abiotic atmosphere of the early Earth 7 . Thus, the false positives do not appear to be important production of NO as an atmospheric "beacon" of life. Model E results show that this trend continues as we increase the proton flux by  another factor of 2. Thus, we conclude that the net production of NO is scaled approximately linearly with the incident proton flux. This could be understood, because 70 to 80% of the energy of incoming protons goes into creation of ionization pair production. Neutral and ion chemistry resulting from ion pair production creates about 1.25 N atoms and about 2 HO x molecules for each incident proton, and the N atoms produced are in the ground state N( 4 S) (45% per ion pair) or the excited state N( 2 D) (55% per ion pair) 31 .

The increase in the NO concentration by 2 to 3 orders of magnitude is driven by the corresponding flux of precipitating protons produced by CME initiated shocks and associated secondary electrons. Each SEP associated CME event exerts a dynamic pressure on the planetary magnetosphere, which perturbs the geomagnetic field and induces geomagnetic currents in the polar regions. The resistive dissipation of these currents heats the ionosphere. The height integrated Joule heating (JH) rate introduced by such currents varies from a few mW/ m 2 (for a regular CME event with the energy of 10 31 ergs) to up to 1 W/m 2 for a super Carrington event with the energy of 2 × 10 33 ergs 7,32 . The JH rate increased by 2 orders of magnitude should be balanced by the radiative and conductive cooling rates. The radiative cooling rates are mostly controlled by greater emission flux from NO molecules due to enhanced production of NO due to SEP mediated dissociation. The generation of large amounts of NO has been shown in Earth's atmosphere to lead to "overcooling" events 33 . That is, so much NO is generated that the resultant infrared cooling leaves the atmosphere colder than it was before the geomagnetic event. NO emission at 5.3 µm is driven by collisional impact with atomic oxygen, and therefore, is dependent on thermospheric abundance of O. The models show no significant change in production of atomic oxygen due to XUV flare emission from the active star (at 10F 0 ) at altitudes below 70 km (Model B). The proton events contribute to the modest (20-40%) destruction of O in the thermosphere. However, the NO emission flux at 5.3 µm depends on the temperature of neutral oxygen, T n , as ~exp (−2700/T n ), because the increase in neutral temperature increases the rate of collisional excitation of NO, while reduction of O plays a secondary role in the production of NO emission flux 34 . The neutral temperature increase is caused by the enhaced Joule heating deposited in the thermosphere during geomagnetic storms, and thus mostly contributes to the rise in NO emission power.

The O 2 signal is proportional to J [O 3 ], where J is the ozone photolysis rate, and the symbol [O 3 ] represents the abundance of O 3 . The ozone abundance also depends on more O 2 photolysis (see R11 of METHODS), it is inversely dependent on temperature, and also on the H, NO, NO 2 , and other chemical abundances (see R13 of METHODS). Figure 5 presents the 2D map of atmospheric ozone destruction driven by XUV flux from an active star and a 10xJuly 2000 SEP event (right panel, Model D) with respect to the base model (left panel; Model A). The Models C and D show that ozone is destroyed up to 70% in the mid latitudes and up to 90% at latitudes over 60°. This is caused by both ozone photolysisand collisional dissociation with energetic particles and enhanced production of NO. The NO radiative cooling is sentitive to the temperature of neutral oxygen as discussed above, and thus, the rapid cooling cuts off the infrared emission -this is a manifestation of the "thermostat" effect discussed above. More detailed modeling of the response of Earth-like planets is required to understand whether NO emission would be prolonged after storms or rather would be short-lived due to overcooling.

The same linear scaling is observed for the increase of steady state resultant mixing ratios of production of HO x (H, OH and HO 2 ) due to dissociation of water vapor via the incoming flux of SEP protons. Figure 4 shows the 2D maps of the OH mixing ratios for the models B, C and D (as in Fig. 3). One can see that the mixing ratio for Model C increases to 100 ppbv at the reference height. As discussed in reference 35 , most of the OH produced is the vibrationally excited hydroxyl molecule; thus the expected power emitted by the 1.6 µm and 2.0 µm bands should increase accordingly by the same factor if a sufficient amount of ozone is available for its production.

We point out that understanding the response of the upper atmosphere of a planet to strong CMEs is still a frontier of research even for the Earth. The current Decadal Survey [http://nap.edu/13060] for Solar and Space Physics identifies this topic as a Key Science Goal for Earth's thermosphere and ionosphere.

Discussion

Our results imply that the total NO emitting flux at 5.3 µm from the planet around an active K to G star (Models C and D) with an N-O 2 rich atmosphere is expected to be ~10 20 -10 22 erg/s. This is consistent with the estimate of the NO power at 5.3 µm during higher stellar activity expected from younger G and K type stars obtained from the linear scaling between X-ray flux (0.1-0.8 nm) GOES measurements with F10.7 flux obtained in 18 extended to F10.7 = 2000. The contribution of the false positive of emitted flux is less than the NO production rate by over 3-4 orders of magnitude, because the emission of NO is mediated by the collsions of atomic O that is strongly suppressed in the abiotic atmosphere 8 . We should note that our model does not account for the thermospheric temperature caused by the energy inputs due to XUV emission and JH, and thus, represents a low bound of expected NO emission fluxes at 5.3 µm from nitrogen-and oxygen rich atmospheres of exoplanets around active stars. The emission power from OH bands −2 × 10 18 -10 20 ergs/s and O 2 at 1.27 µm at least at the level of 2 × 10 21 ergs/s. For a planetary system located at 10 pc away from Earth, this implies the total flux at the Earth integrated over the NO band with the bandwidth of ~5600 Å at 10 −20 -10 −18 ergs/cm 2 /s, the OH bands with the bandwidth of ~2000 Å at 2 × 10 −22 -10 −20 erg/cm 2 /s and O 2 band over the spectral width of 431 Å at ~2 × 10 −19 ergs/cm 2 /s. This suggests that low spectral resolution λ/Δλ = 10-40 would be required to detect emission from these bands. Low spectral resolution (λ/Δλ~20) observations at a signal-to-noise of 10 will require only 1.5 hours of exposure time with the JWST/MIRI spectrograph at ~5 µm. Thus, if future space telescopes have apertures larger than JWST by a factor of 2, the exposure time could be reduced by a factor of 4 and the planets with the 10 times lower NO flux can be detected in just 4 hours. Because the emission flux from NO, OH and O 2 ( 1 Δ) bands are dependent on stellar activity levels driven by geomagnetic storms & XUV flux, it is expected to vary by a factor of 10 to 100 depending on the level of stellar activity on a time scale of storms, or ~2-3 days. This variability time scale should be greater than the expected exposure time. The estimated number of prime Earth twin targets around G-K stars in the neighborhood of 10 pc for the detection of the beacons of life is at least ~20 planets 36,37 .

Conclusion

Based on our analysis of TIMED/SABER data collected from observations of Earth's thermospheric emission in the mid-IR bands and 2D models of atmospheric chemistry of terrestrial type planets around active stars, we conclude that the molecular-band emission from NO at 5.3 µm, OH at 1.66 and 2 µm and O 2 at 1.27 µm is strongly correlated with the level of stellar activity in the form of stellar energetic particle events. The high emission fluxes from these molecules in the mid-IR bands would signify a nitrogen-rich, oxygen rich and water rich atmosphere with the atmospheric pressure (significant fraction of 1 bar), which represent the fundamental requirements for habitability referred to as atmospheric "beacons of life". Our models suggest that ozone in the atmospheres of habitable exoplanets with high NO and OH fluxes should significantly depleted at all lattitudes via reactions with NO x and OH x species (see Fig. 5).

Although the raw signal itself from NO is observable as noted above, however, its size is small compared to the thermal emission from the exoplanet, which is ~10 2 larger, and much smaller than the emission from the host star, which can be ~10 6 greater for a star similar to the Sun. Thus, a possible observational strategy available in the near term, using JWST, would be to perform eclipse spectroscopy, where thermal emission from the exoplanet is observed 38,39 . Potential targets could be found by TESS and then observed with JWST. Ideally the host star would be known to be active, and, if possible, observed close in time by optical or UV observatories to correlate the eclipse observations with recent activity. The proposed time-varying "atmospheric beacons of life" can be observed using direct imaging techniques in the mid IR bands via recently proposed "Exo-Life Beacon Space Telescope", an extended version of FKSI space interferometer 39,40 .

Methods

2-D GSFC Atmospheric Model.

We employed the Goddard Space Flight Center (GSFC) two-dimensional (2-D) atmospheric model to study the impact of solar protons on the Earth atmospheric chemistry 41,42 . The vertical range of the model is equally spaced in log pressure and extends from the ground to approximately 92 km (0.0024 hPa) with a 1 km grid spacing and 4 degree latitude grid spacing. The transport is computed off-line and is derived using the daily average global winds and temperatures from the NASA Modern Era Retrospectiveanalysis for Research and Applications (MERRA) meteorological analysis (see the website: http://gmao.gsfc.nasa. gov/research/merra/) for 1979-2012. Thirty-day running averages of the residual circulation, eddy diffusion, zonal mean wind, and zonal mean temperature are computed using the methodology described in 43 and are used as input into the GSFC 2-D model.

The ground boundary conditions in the GSFC 2-D model for the source gases are taken from WMO (2011) for year 2000. The model uses a chemical solver described in [43][44][45] . The photochemical gas and heterogeneous reaction rates and photolysis cross sections have been updated to the Jet Propulsion Laboratory recommendations from year 2010 for these computations 46 . We use the solar proton flux (energies 1 to 300 MeV) for the July 14-16, 2000 SEP event provided by the National Oceanic and Atmospheric Administration (NOAA) Space Weather Prediction Center (SWPC) for the NOAA Geostationary Operational Environmental Satellites (GOES) (see http://www.swpc.noaa.gov/ftpmenu/lists/ particle.html). The GOES 13 data are considered to be the most reliable of the current GOES datasets for the proton fluxes depositing energy into polar latitudes and were used as the source of protons in several energy intervals for the July 2000 SEP event (see also at http://www-istp.gsfc.nasa. gov/istp/events/2000july14/20000716_proton.gif). Peak ionization rates above 10000 cm −3 s −1 and the energy deposition rate of 5 × 10 −7 ergs/cm 3 /s were reached on July 15, 2000.

The proton flux data were used to compute the ion pair production profiles employing the energy deposition methodology discussed in 46 , where the creation of one ion pair was assumed to require 35 eV. The SEP-produced hourly average ionization rates and the energy deposition rates in the polar cap regions ( > 60 geomagnetic latitude) are given in Figs 6 and 7, respectively, for July 14-16 of 2000 SEP event. The GOES proton flux during the July 14-16 of 2000 event as well as the impact on the atmosphere is discussed in 47 . We use the daily average ionization rates for July 15, 2000 (the maximum energy deposition day of this SEP event) in the computations shown in the paper.

This model referred to as Model A serves as the reference model for calculation of atmospheric chemistry for Model B with 10x enhanced XUV flux and Models C, D, and E for 1x, 10x, and 20x of the particles fluxes, respectively.   (R4) and (R5) are the major sources of production of NO that becomes vibrationally excited by impacts with atomic oxygen in the ionosphere-thermosphere (IT), and thus are temperature dependent. The hydroxyl production is controlled by photolysis of water and collisional dissociation

Production and Destruction of NO and OH.

Figure 1 .
1Total emission power (in units of 0.1 TW): upper panel: OH (9→7 + 8→6) at 2 μm; lower panel: OH (5→3 + 4→2) power at 1.6 μm.

Figure 2 .
2The daily averages of the total emitting power (in units of 0.1 TW) by the Earth as a dot from O 2 ( 1 Δ) at 1.27 μm.

Figure 3 .
32D map of steady state NO mixing ratio (in ppbv): Left: Model B output, Middle: Model C output and Right: Model D output; Contour level: 0.1, 1, 2, 5, 10, 20, 50, 100, 200, 500, 1000, & 2000 ppbv.

Figure 4 .
42D map of steady state OH mixing ratio (in ppbv): Model B (left panel), Model C (middle panel) and Model D (right panel); Contour level: 0.1, 1, 2, 5, 10, 20, 50, 100 ppbv.

Figure 5 .
5The 2D map of atmospheric ozone destruction driven by XUV flux from an active star and a 10xJuly 2000 SEP event (right panel, Model D) with respect to the base model (left panel; Model A). Scientific RepoRts | 7: 14141 | DOI:10.1038/s41598-017-14192-4

as other products, see9,10 . The dominant sources of NO production are

Figure 6 .
6Ionization rates (in units of # cm −3 s −1 ) for July 2000 SPE event.

Figure 7 .
7Energy deposition (in units of 10 −9 ergs cm −3 s −1 ) for July 2000 SPE. Scientific RepoRts | 7: 14141 | DOI:10.

Destruction of Thermospheric Ozone. Ozone production comes from the following reactions Ozone destruction is mediated via the following reactions Catalytic destruction of ozone is driven by the following reactions X is not destroyed but continuously participates in the cycle. availability statement. Observational data on OH and O 2 emission fluxes are available from TIMED/SABER mission at https://gcmd.nasa.gov/records/GCMD_TIMED_SABER.html. The 2D GSFC atmospheric model data are available at NASA Goddard Space Flight Center. The results of simulations are available upon request from the corresponding author.+
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© The Author(s) 2017
AcknowledgementsThe authors would like to thank the referees for constructive suggestions that improved and clarified the major findings of this paper. VA's work was supported by internal funding from NASA GSFC's Sellers Exoplanetary Environments Collaboration (SEEC) and by NASA's Exobiology program, Grant No. 80NSSC17K0463. VA performed the part of this work while staying at ELSI/Tokyo Institute of Technology, Japan.Author ContributionsV.S.A. conceived and designed the numerical experiments, analysed the data, contributed materials and wrote the manuscript. C.J. contributed to the development and execution of codes and data analysis, M.M. and L.H. contributed to the data analysis, W.D. contributed to development of the manuscript and to data analysis.Additional InformationCompeting Interests: The authors declare that they have no competing interests.Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.
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Self-reported evaluation of competencies and attitudes by physicians-in-training before and after a single day legislative advocacy experience

Kristin M Huntoon
Colin J Mccluney
Elizabeth A Wiley
Christopher A Scannell
Richard Bruno
Matthew J Stull
Self-reported evaluation of competencies and attitudes by physicians-in-training before and after a single day legislative advocacy experience
R E S E A R C H A R T I C L E Open Access
Background: Advocacy is increasingly being recognized as a core element of medical professionalism and efforts are underway to incorporate advocacy training into graduate and undergraduate medical school curricula. While limited data exist to quantify physician attitudes toward advocacy, even less has been done to assess the knowledge, skills, and attitudes of future physicians. The purpose of this study was to assess students' experiences and attitudes toward legislative advocacy, cutting out using a convience sample. Methods: A paper survey based on previously validated surveys was administered to a convenience sample of premedical and medical student participants attending a National Advocacy Day in Washington, DC, in March 2011, both before and after their advocacy experiences. Responses were anonymous and either categorical ( or ordinal, using a 5-point Likert scale. Data were analyzed statistically to evaluate demographics and compare changes in preand post-experience attitude and skills. Results: Data from 108 pre-advocacy and 50 post-advocacy surveys were analyzed yielding a response rate of 46.3%. Following a single advocacy experience, subjects felt they were more likely to contact their legislators about healthcare issues (p = 0.03), to meet in person with their legislators (p < 0.01), and to advocate for populations' health needs (p = 0.04). Participants endorsed an increased perception of the role of a physician advocate extending beyond individual patients (p = 0.03). Participants disagreed with the statement that their formal curricula adequately covered legislative healthcare advocacy. Additionally, respondents indicated that they plan to engage in legislative advocacy activities in the future (p < 0.01). Conclusions: A one-time practical advocacy experience has a positive influence on students' knowledge, skills and attitudes towards legislative advocacy. Practical experience is an important method of furthering medical education in advocacy and further research is necessary to assess its impact in a broader population.

Background

The role of advocacy training in medical education has generated significant controversy [1]. While some have questioned the potential politicization of medical schools and academic medical centers [2], advocacy has increasingly been recognized as a core element of medical professionalism [3], and efforts are underway to incorporate advocacy training into graduate and undergraduate medical school curricula [4][5][6]. Although there is no unified definition of physician advocacy [7], a growing number of specialty societies now recognize advocacy as a professional responsibility [8,9] and some require advocacy training and experience for trainees [10]. One compelling working definition of physician advocacy is "action by a physician to promote those social, economic, educational, and political changes that ameliorate the suffering and threats to human health and well-being that he or she identifies through his or her professional work and expertise." [7] By virtue of the role physicians play in society and the unique features of the doctorpatient relationship [11,12], physicians and physicians-in-training are uniquely suited to advocate with and for patients.

To develop effective physician advocates, longitudinal skill development is essential from the outset of training [13]. The importance of this objective at the medical school level is outlined in the AAMC's Medical School Objectives Project (MSOP) [14] and there are several medical schools with novel health policy programs [15][16][17][18][19]. These programs are highly valued by the limited number of trainees able to access them [20]. Exposure to policy, however, is not synonymous with exposure to advocacy, and most physicians-in-training do not have access to a comprehensive advocacy curriculum or even isolated advocacy experiences in formal curricula.

The aim of our study was to evaluate the impact of a single, half-day advocacy experience on a group of premedical and medical students participating in a National Advocacy Day as part of the American Medical Student Association's (AMSA) Annual Convention in Washington, D.C. Participants were attendees at the Convention who elected to participate in Advocacy Day. Convention attendees are self-funded; there was no additional cost to participate in Advocacy Day. We evaluated the impact through pre-and post-surveys to assess knowledge, skills, and attitudes regarding legislative advocacy. While many organizations offer comparable advocacy opportunities on Capitol Hill for physicians and physiciansin-training, no previous studies have included a preand post evaluation of such an experience for American physicians-in-training. We sought to evaluate the impact of a single, practical advocacy experience on the attitudes and perspectives of physicians-in-training in the context of a growing recognition of the need for advocacy training.

Methods

Population

We surveyed a convenience sample of participants attending AMSA's Advocacy Day in Washington, D.C., in March 2011. Participants chose a topic area with a specific legislative "ask" to discuss during visits with Congressional offices. Topic areas included healthcare access, student debt reduction, global health funding, and lesbian, gay, bisexual, and transgender (LGBT) health equity. As part of this event, physicians-in-training had the option of participating in a pre-Convention webinar and/or a two-hour in-person training session. Meetings were coordinated for participants with legislators and/or their staff. Each participant was scheduled to meet with a minimum of two federal Congressional offices in groups of two or more, and a concerted effort was made to ensure that physicians-in-training met with their respective legislators. Participation in the study was completely voluntary and no incentives were offered for participation. If participants consented, they were instructed to complete a pre-survey prior to training and a postsurvey following the training and advocacy experience on Capitol Hill. Participants who did not participate in the in-person training did not receive surveys. Surveys were returned on-site or mailed directly to the AMSA national office.

Survey design and testing

We designed the survey instrument to evaluate participants' skills, attitudes, and past experiences with advocacy based on previously validated surveys in the existing literature [21,22]. Text was updated to align with the pre/post nature of the study. We used a paper survey to gather data from participants. Basic demographic information was collected. In addition, the survey and post-surveys each contained 14 identical five-point Likert scale questions. The postsurvey contained an additional three five-point Likert scale questions. We designed these questions to collect medical students' self-assessment of knowledge, skills and attitudes toward legislative advocacy. This study was conducted with Oregon Health & Science University Institutional Review Board approval.

Data collection

In compliance with institutional review board requirements, we deidentified all data collected such that each survey response could not be linked to any specific individual. We numbered surveys to allow for comparison between individual pre-and post-advocacy responses.

Measures and variables

Response categories were either categorical (gender, medical school, medical school class, political selfidentification, etc.), or ordinal (strongly disagree, disagree, neutral, agree, or strongly agree). We included a single open-ended question to obtain qualitative feedback on the participants' experiences. Measures were calculated percentages of collated responses per category based on the total number of completed responses.

Statistical analysis

We calculated descriptive statistics for demographics and responses to survey questions. We performed paired t-tests to compare pre-and post-experience attitude and skill changes. The quantitative data were managed and analyzed using Microsoft Excel.

Results

While precise numbers are not known, the American Medical Student Association estimates that approximately 200 students participated in the National Advocacy Day. Of these, approximately 150 students are believed to have participated in the pre-advocacy in-person training and would have received surveys. One hundred twenty-two participants completed the primary survey; of these, 14 were excluded, as they did not fully complete the survey. Of the remaining 108 participants, 50 participants completed a secondary survey, for a response rate of 46.3%. Fifty-eight percent of respondents were female, 40% were male and one participant did not respond. Pre-medical school trainees were 32% of respondents, pre-clinical trainees consisted of 40% of respondents (MSI -16%, and MSII -24%), clinical trainees consisted of 26% of respondents (MSIII -18% and MSIV-8%) and there was one M.D./Ph.D. student. The average age of respondents was 25.0 ± 4.2 years old ( Table 1).

The majority (56%) of participants chose to advocate in support of improving health care access. A fifth of participants chose to advocate on student debt reform (20%). The remaining students were split with 14% choosing to advocate for global health funding and 10% advocating for LGBT health equity (Table 1).

We polled participants on their prior experience with in-person legislative advocacy. For more than a third (38%) of participants, this was their first legislative advocacy experience. The remainder indicated having engaged in at least one prior advocacy activity (Table 1). Nineteen participants (38%) had prior in-person advocacy experience.

For the remainder of the survey, participants selfassessed their knowledge, skills, and attitudes regarding legislative healthcare advocacy, both prior to and immediately following Congressional advocacy visits to assess any changes as a result of the Advocacy Day experience. We included three additional statements in the postsurvey to assess preparedness and attitudes following the advocacy experience.

Knowledge

As the survey was administered almost a year after passage of the Patient Protection and Affordable Care Act (PPACA), we assessed knowledge with the statement, "I understand the major provisions of the recently enacted health care reform legislation (Patient Protection and Affordable Care Act)." Although most of the participants felt they had a strong grasp on the content of PPACA prior to lobbying, a 0.3 Likert scale increase was noted in the post-advocacy survey (p = 0.03) ( Table 2).

We surveyed participants on their baseline knowledge prior to any of the advocacy training provided by AMSA by prompting them with, "My medical school curriculum has provided me with sufficient health legislative advocacy training." We obtained the lowest Likert scale scores of any prompts in the survey in response to this statement; the pre-survey average was 2.02 and in post-advocacy surveys this remained fairly constant at 1.99 (p = 0.89). In order to demonstrate an understanding of the role of policy upon patients, we asked participants to respond to the prompt, "I can describe how public policy affects the health of populations that I serve." An average 0.26 Likert scale score increase was observed in post-advocacy respondents compared to their pre-survey responses (p = 0.02) ( Table 2).

To determine whether knowledge of the legislative process would empower participants to partake in future opportunities, we prompted participants with, "I can identify the opportunities available for physicians-in-training to function as health advocates." The post-survey responses showed an increase of 0.58 from pre-surveys, suggesting that from this single day experience, participants could identify ways in which to be active health advocates (p < 0.001) ( Table 2). { Participants responded to the prompt: "What topic will you be lobbying on (select one)?". } Participants responded to the prompt: "What type of contact have you had with a legislator or staffer prior to today's visits (check all that apply)?" If the response was anything other than "None", participants were said to have had at least one prior experience.

Skills

We used several prompts to gain insight into whether the Advocacy Day experience further developed participants' legislative advocacy skills. The first prompt sought to evaluate their ability to make a legislative ask: "I am able to effectively communicate my position to my legislators and/or their staffers." Post-survey data showed an increase of 0.57 on the Likert scale, indicating an increased confidence in participants' ability to communicate (p < 0.01).

To address whether the Advocacy Day experience helped participants craft goals and expectations for their meetings with Congressional leaders, we included the prompt, "I know what to expect when I meet with legislators and their staffers." Post-survey measurements produced a 0.5 increase in Likert scale scores as compared to the presurvey (p < 0.001) ( Table 2). The last skills-oriented category assessed participants' attitudes toward visits and their role in political advocacy, both currently and in the future. Participants responded to the prompt, "As a physician-in-training, I believe I can influence policy." We noted strong support for this statement (4.16 before and 4.20 after) but no statistically significant difference (p = 0.72) between pre-advocacy and post-advocacy responses. (Table 2).

Attitude

We prompted participants, "As a physician-in-training, I believe it is important to contact my legislators about issues important to my future patients." Participants strongly agreed with this statement, with a pre-advocacy survey average of 4.50 and a post-advocacy survey average of 4.64; the difference of 0.14 was not statistically significant (p = 0.13). Participants responded to the prompt, "As a physician-in-training, I believe it is important to contact my legislators about issues that will affect the way I will practice medicine." The post-advocacy survey yielded a 0.4 increase in comparison to pre-advocacy survey results (p = 0.03) ( Table 2). n/a 4.46 n/a n/a * Participants were asked to react to the following statements using a 5-point Likert scale with 1 being "Strongly disagree" and 5 being "Strongly agree" † These statements were included only on the post-survey.

To determine whether Advocacy Day participation would affect participants' view of advocacy as a professional responsibility, we prompted respondents with, "Participating in the legislative process is a professional responsibility of physicians". Post-advocacy responses showed a non-significant increase of 0.24 from preadvocacy results (p = 0.17). To assess participants' perception of the value of legislative advocacy, we prompted respondents with, "Meeting with legislators is a worthwhile use of my time." This resulted in a substantial difference, with pre-advocacy surveys averaging 3.74 and postsurvey responses yielding an average of 4.4 (p = 0.007) ( Table 2).

To address participants' attitudes with respect to health inequities, we prompted them with, "It is part of my role as a physician-in-training to advocate for populations' health needs within society." We noted a 0.44 increase in the post-survey answers from 4.10 to 4.54 (p = 0.04). We asked participants to respond to the prompt, "I feel that my role as a health advocate extends beyond the individual patient(s) I am treating." Postadvocacy survey answers yielded a 0.46 increase from the pre-surveys (p = 0.03). Finally, attitudes about participants' willingness and desire to participate in future advocacy efforts were evaluated by the prompt, "I plan to engage in health legislative advocacy activities in the future." We recorded another substantial increase between pre-and post-survey responses in this category with an increase of 0.64 (p < 0.006) (Table 2, Figure 1).

We included three additional statements on the postsurvey to assess for possible changes of perspective following the advocacy experience. All three questions ranked highly with an average Likert score between "Agree" and "Strongly Agree". The statement, "After participating in Advocacy Day, I feel more prepared to be a physician-advocate," garnered an average score of 4.30; the statement, "Participating in Advocacy Day has increased my commitment to engaging in health advocacy activities," had an average score of 4.37; and the final statement, "I am more likely to encourage others to engage in health advocacy activities as a result of my participation in Advocacy Day," received an average Likert score of 4.46 (Table 2).

Discussion

We believe that this study is the first to assess the changes in skills and attitudes of U.S. medical trainees as a result of a single day legislative advocacy experience. Although various physician and medical student organizations offer advocacy experiences, the AMSA Advocacy Day experience was open to all levels of medical trainees and was less limited in scope, as participants were able to select a topic and specific ask to discuss with Congressional offices from a predetermined set of options (healthcare access, student debt reduction, global health funding, and LGBT health equity). Thus, students were able to select an issue that resonated with them and that was aligned with their individual ethical/moral convictions or motivations.

Participants rated their exposure to health policy in formal curricula poorly. This may be attributable to the disproportionate representation of premedical and preclinical students among participants (Table 2). Nonetheless, this finding suggests a further need for medical schools to integrate a comprehensive longitudinal health policy curriculum throughout training, including the development of skills in addition to a review of current policy. Interestingly, our results show that the advocacy day experience itself promoted health policy knowledge: following the brief training and advocacy experience, participants indicated an increased knowledge of both PPACA and how health policy can affect the populations they serve (Table 2).

Likewise, after engaging in the advocacy day experience, participants were able to identify future opportunities to serve as health advocates (Table 2). While our respondents indicated that their health policy curricula are lacking (Table 2), our results suggest that advocacy events or projects with a hands-on component can be a valuable component of enhancing policy education. Our survey participants also demonstrated that, in addition to training on the skills and techniques of advocacy, the actual experience of meeting with legislators to discuss policy and communicate positions is an important component of empowering physicians-in-training as future advocates -after the advocacy experience, respondents indicated they felt better able to anticipate the goals and expectations of such a meeting, and felt that they were more prepared to be a physician-advocate (Table 2). Some of the highest Likert scale scores, both from the pre-and post-surveys were those in the attitudes section. Our results continue to support the notion that physicians-in-training view advocacy as an extension of their duty to their patients and their care. While participants initially acknowledged a responsibility to advocate with and for underserved populations, their legislative advocacy experiences reinforced that commitment. Although Likert scale scores reflecting a positive attitude xadvocacytowards advocacy approached the ceiling of the survey, we still found a statistically significant increase following the legislative meetings, indicating that participants believed that the experience was worth the effort. Despite a high baseline, students expressed a significant increase in their plans to engage in health legislative advocacy in the future ( Figure 1). Notably, the high mean Likert scores for the three statements exclusive to the post-survey indicated that participants had an increased commitment and were likely to engage in advocacy efforts in the future ( Table 2).

Optional freeform comments provided by participants anecdotally support many of the findings of this study. One participant reported that, "Today was a wonderful opportunity for me to expand my knowledge on health care reform acts currently being reviewed. I had a great experience overall at advocacy and I was inspired to continue advocating!" Another participant described how, "This experience increased my enthusiasm to share my opinion with the legislative community." One participant described the experience as "amazing," noting that, "It relates to our future what we do now, and through this visit you get the sense that you're not just going to be a physician but a part of the system that suffers, aides, changes, etc." Lastly, after experiencing three legislative meetings, one student wrote simply, "The first one was jarring. The second one, exciting. The third one was empowering."

Our findings represent a small, self-selected sample of physicians-in-training who have opted to participate voluntarily in an advocacy experience limiting the generalizability of our results. Although Advocacy Day was theoretically open to any physician-in-training, advertising for the event was targeted at AMSA members and Convention attendees. As a result, the study sample may not be reflective of the attitudes and opinions of the general premedical or medical student population. While this may affect Likert scores for any specific question, it is less likely that this would impact the differences between paired pre-and post-scores, helping to mitigate any effects of sampling bias in the findings. Some statements had results that approached the ceiling of the survey, making it unlikely that any significant change could be assessed following the advocacy experience. This effect was most notable in the "attitude" category; however, most statements in this category still showed statistically significant changes allowing for analysis and interpretation.

These limitations are common to most studies to date regarding advocacy, largely due to the nascent stage of advocacy education in medicine. As such, our study represents foundational work in the practice and study of healthcare advocacy. While much thought and discussion must continue around the integration of advocacy into medical curricula, we demonstrate that even single experiences can improve the perceived commitment trainees have to advocacy. Further validation of our work is encouraged as the long-term effects of single and longitudinal experiences with advocacy should be assessed. Such longitudinal studies regarding participants' continued involvement in advocacy activities would be valuable in demonstrating the effectiveness of early advocacy training in producing long-term behavior change and potential patient benefit. Future studies would benefit from increased sample size and advocacy experiences targeted at a broader range of students, ideally in situations in which participation is not optional. Lastly, an evaluation of existing advocacy programs in medical education and their effectiveness would allow for the development of best practices and allow for further dissemination of methods for advancing these valuable skills.

Conclusions

A single advocacy experience for physicians-in-training increases their appreciation of the importance of health care advocacy and of being active in the legislative process; and reinforces their perception that advocacy training and experiences are missing components of their schools' curricula. Practical experience is an important method of furthering medical education in advocacy and encouraging this aspect of medical professionalism amongst future physicians.

Figure 1
1Responses to "I plan to engage in health legislative activities in the future". Chart showing the number of responses received for each Likert score value (1 = Strongly Disagree to 5 = Strongly Agree) on pre-and post-advocacy surveys in response to the statement, "I plan to engage in health legislative activities in the future." The mean Likert value increased from 3.88 to 4.52 (a change of 0.64) (p < 0.006) between pre-and post-advocacy surveys.

Table 1
1Demographics of survey respondentsParticipants responded to the prompt: "Year of Training (select one)".RESPONSES
n (%)

Primary Survey
122

Secondary Survey (response rate)
50 (46.3%)

GENDER *
n (%)

Female
29 (58.0%)

Male
20 (40.0%)

Other
1 (2.0%)

AGE
25.0 ± 4.2 years

YEAR OF TRAINING  †
n (%)

Pre-medical school
16 (32.0%)

Medical school, pre-clinical
20 (40.0%)

MS1
8 (16.0%)

MS2
12 (24.0%)

Medical school, clinical
13 (26.0%)

MS3
9 (18.0%)

MS4
4 (8.0%)

M.D./Ph.D. training
1 (2.0%)

TOPIC {
n (%)

Health Care for All
28 (56.0%)

Student Debt
10 (20.0%)

Global Health
7 (14.0%)

LGBT
5 (10.0%)

PRIOR EXPERIENCE }
n (%)

No prior experience
19 (38.0%)

At least one prior experience
31 (62.0%)

*

Freeform response

 †

Table 2
2Pre-and post-advocacy mean Likert score responses to survey statementsIt is part of my role as a physician-in-training to advocate for populations' health needs within society.Survey Statement *

http://www.biomedcentral.com/1472-6920/12/47
AcknowledgementsThe authors would like to acknowledge Dr. Paul Gorman for his assistance in development of the survey instrument and in gaining review board approval. They would also like to thank Deb Hall, Sonia Lazreg and John Brockman for their assistance in planning and executing AMSA's Advocacy Day.Competing interestThe authors have no conflicts of interest to disclose.Authors' contributions KMH participated in study design, data collection, and drafted the manuscript. CJM participated in data collection, data analysis, drafted the manuscript and made subsequent edits. EAW conceived of the study, participated in study design, data collection and helped to draft the manuscript. CAS participated in data collection, analyzed the data, and helped to draft the manuscript. RB participated in data collection, data analysis, and helped to draft the manuscript. MJS conceived of the study, participated in study design, data collection, and helped to draft the manuscript. All authors read and approved the final manuscript.
American Medical Student Association, 45610 Woodland Rd. Oregon Health & Science University. 3003University of Washington School of Medicine ; George Washington University School of Medicine ; Department of Emergency Medicine, University of Cincinnati School of MedicineSuiteUniversity of Washington School of Medicine, Seattle, WA, USA. 3 American Medical Student Association, 45610 Woodland Rd, Suite 300, Sterling, VA 20166, USA. 4 George Washington University School of Medicine, Washington, DC, USA. 5 University of Southern California, Los Angeles, CA, USA. 6 Oregon Health & Science University, Portland, OR, USA. 7 Department of Emergency Medicine, University of Cincinnati School of Medicine, Cincinnati, OH, USA. References

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Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution. Huntoon, BMC Medical Education. 1247Self-reported evaluation of competencies and attitudes by physicians-in-training before and after a single day legislative advocacy experience. Submit your manuscript at www.biomedcentral.com/submitCite this article as: Huntoon et al.: Self-reported evaluation of competencies and attitudes by physicians-in-training before and after a single day legislative advocacy experience. BMC Medical Education 2012 12:47. Submit your next manuscript to BioMed Central and take full advantage of: • Convenient online submission • Thorough peer review • No space constraints or color figure charges • Immediate publication on acceptance • Inclusion in PubMed, CAS, Scopus and Google Scholar • Research which is freely available for redistribution Submit your manuscript at www.biomedcentral.com/submit