Revisiting rho 1 Cancri e: A New Mass Determination Of The Transiting super-Earth

We present a mass determination for the transiting super-Earth rho 1 Cancri e based on nearly 700 precise radial velocity (RV) measurements. This extensive RV data set consists of data collected by the McDonald Observatory planet search and published data from Lick and Keck observatories (Fischer et al. 2008). We obtained 212 RV measurements with the Tull Coude Spectrograph at the Harlan J. Smith 2.7 m Telescope and combined them with a new Doppler reduction of the 131 spectra that we have taken in 2003-2004 with the High-Resolution-Spectrograph (HRS) at the Hobby-Eberly Telescope (HET) for the original discovery of rho 1 Cancri e. Using this large data set we obtain a 5-planet Keplerian orbital solution for the system and measure an RV semi-amplitude of K = 6.29 +/- 0.21 m/s for rho 1 Cnc e and determine a mass of 8.37 +/- 0.38 M_Earth. The uncertainty in mass is thus less than 5%. This planet was previously found to transit its parent star (Winn et al. 2011, Demory et al. 2011), which allowed them to estimate its radius. Combined with the latest radius estimate from Gillon et al. (2012), we obtain a mean density of rho = 4.50 +/- 0.20 g/cm^3. The location of rho 1 Cnc e in the mass-radius diagram suggests that the planet contains a significant amount of volitales, possibly a water-rich envelope surrounding a rocky core.Comment: 16 pages, 5 figures, accepted for publication in the Astrophysical Journal (the 300+ RV measurements will be published as online tables or can be obtained from the author

Evidence of Titan's Climate History from Evaporite Distribution

Water-ice-poor, 5-$\mu$m-bright material on Saturn's moon Titan has previously been geomorphologically identified as evaporitic. Here we present a global distribution of the occurrences of the 5-$\mu$m-bright spectral unit, identified with Cassini's Visual Infrared Mapping Spectrometer (VIMS) and examined with RADAR when possible. We explore the possibility that each of these occurrences are evaporite deposits. The 5-$\mu$m-bright material covers 1\% of Titan's surface and is not limited to the poles (the only regions with extensive, long-lived surface liquid). We find the greatest areal concentration to be in the equatorial basins Tui Regio and Hotei Regio. Our interpretations, based on the correlation between 5-$\mu$m-bright material and lakebeds, imply that there was enough liquid present at some time to create the observed 5-$\mu$m-bright material. We address the climate implications surrounding a lack of evaporitic material at the south polar basins: if the south pole basins were filled at some point in the past, then where is the evaporite

AMPA receptors control fear extinction through an Arc-dependent mechanism

Activity-regulated cytoskeleton-associated protein (Arc) supports fear memory through synaptic plasticity events requiring actin cytoskeleton rearrangements. We have previously shown that reducing hippocampal Arc levels through antisense knockdown leads to the premature extinction of contextual fear. Here we show that the AMPAR antagonist CNQX elevates hippocampal Arc levels during extinction and blocks extinction that can be rescued by reducing Arc. Increasing Arc levels with CNQX also overcomes the actin-destabilizing properties cytochalasin D and promotes extinction. Therefore, extinction is dependent on AMPA-mediated reductions of Arc via a mechanism consistent with a role for Arc in stabilizing the actin cytoskeleton to constrain extinction

Calibration of the APEX Model to Simulate Management Practice Effects on Runoff, Sediment, and Phosphorus Loss

Process-based computer models have been proposed as a tool to generate data for Phosphorus (P) Index assessment and development. Although models are commonly used to simulate P loss from agriculture using managements that are different from the calibration data, this use of models has not been fully tested. The objective of this study is to determine if the Agricultural Policy Environmental eXtender (APEX) model can accurately simulate runoff, sediment, total P, and dissolved P loss from 0.4 to 1.5 ha of agricultural fields with managements that are different from the calibration data. The APEX model was calibrated with field-scale data from eight different managements at two locations (management-specific models). The calibrated models were then validated, either with the same management used for calibration or with different managements. Location models were also developed by calibrating APEX with data from all managements. The management-specific models resulted in satisfactory performance when used to simulate runoff, total P, and dissolved P within their respective systems, with r2 \u3e 0.50, Nash– Sutcliffe efficiency \u3e 0.30, and percent bias within ±35% for runoff and ±70% for total and dissolved P. When applied outside the calibration management, the management-specific models only met the minimum performance criteria in one-third of the tests. The location models had better model performance when applied across all managements compared with management-specific models. Our results suggest that models only be applied within the managements used for calibration and that data be included from multiple management systems for calibration when using models to assess management effects on P loss or evaluate P Indices

A Second Giant Planet in 3:2 Mean-Motion Resonance in the HD 204313 System

We present 8 years of high-precision radial velocity (RV) data for HD 204313 from the 2.7 m Harlan J. Smith Telescope at McDonald Observatory. The star is known to have a giant planet (M sin i = 3.5 M_J) on a ~1900-day orbit, and a Neptune-mass planet at 0.2 AU. Using our own data in combination with the published CORALIE RVs of Segransan et al. (2010), we discover an outer Jovian (M sin i = 1.6 M_J) planet with P ~ 2800 days. Our orbital fit suggests the planets are in a 3:2 mean motion resonance, which would potentially affect their stability. We perform a detailed stability analysis, and verify the planets must be in resonance.Comment: Accepted for publication in Ap

The McDonald Observatory Planet Search: New Long-Period Giant Planets, and Two Interacting Jupiters in the HD 155358 System

We present high-precision radial velocity (RV) observations of four solar-type (F7-G5) stars - HD 79498, HD 155358, HD 197037, and HD 220773 - taken as part of the McDonald Observatory Planet Search Program. For each of these stars, we see evidence of Keplerian motion caused by the presence of one or more gas giant planets in long-period orbits. We derive orbital parameters for each system, and note the properties (composition, activity, etc.) of the host stars. While we have previously announced the two-gas-giant HD 155358 system, we now report a shorter period for planet c. This new period is consistent with the planets being trapped in mutual 2:1 mean-motion resonance. We therefore perform an in-depth stability analysis, placing additional constraints on the orbital parameters of the planets. These results demonstrate the excellent long-term RV stability of the spectrometers on both the Harlan J. Smith 2.7 m telescope and the Hobby-Eberly telescope.Comment: 38 pages, 10 figures, 6 tables. Accepted for publication in Ap

Diagnosis and Management of Pseudoguttata: A Literature Review

Corneal pseudoguttata (PG), also known as pseudoguttae or secondary guttata, is a transient, reversible endothelial edema commonly associated with anterior segment pathology. While considered rare, PG presents on slit-lamp examination more commonly than originally thought. We have clinically observed PG after refractive surgeries, in association with infectious keratitis, and following medication use. PG presents as dark lesions on slit-lamp exam with specular illumination, similar to primary corneal guttata. PG is distinct from guttata because PG resolves over time and does not involve Descemet’s membrane. Other ocular findings that may be confused with guttata include endothelial blebs (EB) and endothelial denudation (ED). EB are possibly a type of PG that present after contact lens use or hypoxia. ED is a distinct entity that is characterized by loss of endothelial cells without involvement of Descemet’s membrane. Confocal microscopy may be useful in differentiating these four endothelial lesions, with differences in border definition and the presence of hyperreflective areas two main distinctions. PG presents as a hyporeflective, elevated shape without clear borders on confocal microscopy. PG, EB, and ED can resolve with time without the need for surgical intervention, unlike corneal guttata. Treatment of the underlying condition will lead to resolution of both PG and EB

Diagnosis and Management of Pseudoguttata: A Literature Review

Corneal pseudoguttata (PG), also known as pseudoguttae or secondary guttata, is a transient, reversible endothelial edema commonly associated with anterior segment pathology. While considered rare, PG presents on slit-lamp examination more commonly than originally thought. We have clinically observed PG after refractive surgeries, in association with infectious keratitis, and following medication use. PG presents as dark lesions on slit-lamp exam with specular illumination, similar to primary corneal guttata. PG is distinct from guttata because PG resolves over time and does not involve Descemet’s membrane. Other ocular findings that may be confused with guttata include endothelial blebs (EB) and endothelial denudation (ED). EB are possibly a type of PG that present after contact lens use or hypoxia. ED is a distinct entity that is characterized by loss of endothelial cells without involvement of Descemet’s membrane. Confocal microscopy may be useful in differentiating these four endothelial lesions, with differences in border definition and the presence of hyperreflective areas two main distinctions. PG presents as a hyporeflective, elevated shape without clear borders on confocal microscopy. PG, EB, and ED can resolve with time without the need for surgical intervention, unlike corneal guttata. Treatment of the underlying condition will lead to resolution of both PG and EB