HD 4915: A Maunder Minimum Candidate

We study the magnetic activity cycle of HD 4915 using the \ion{Ca}{2} H \& K emission line strengths measured by Keck I/HIRES spectrograph. The star has been observed as a part of California Planet Search Program from 2006 to present. We note decreasing amplitude in the magnetic activity cycle, a pattern suggesting the star's entry into a Magnetic Grand Minimum (MGM) state, reminiscent of the Sun's Maunder and Dalton Minima. We recommend further monitoring of the star to confirm the grand minimum nature of the dynamo, which would provide insight into the state of the Sun's chromosphere and the global magnetic field during its grand minima. We also recommend continued observations of H \& K emission lines, and ground or space based photometric observations to estimate the sunspot coverage.Comment: To be submitted to AAS Journals; comments welcom

Integrating Lethal and Nonlethal Approaches for Management of Suburban Deer

Evaluations of white-tailed deer (Odocoileus virginianus) population management in suburban landscapes has included debate over lethal control (e.g., sharp-shooting and hunting). These management techniques are often stymied by political impediments, safety concerns, and public attitudes. We are implementing the novel use of surgical sterilization in combination with hunting to mitigate deer-related impacts on Cornell University lands near Ithaca, New York. The project lands are composed of 2 zones: a suburban core campus area (446 ha) and adjacent outlying areas that contain agricultural fields and natural areas where deer hunting is permitted (582 ha). Surgical sterilization will be the primary technique used to reduce deer abundance and associated impacts in the core campus zone. Population reduction in the hunting zone will focus on increased harvest of female deer. During 2007 to 2009, project staff sterilized 58 female deer; 39 adult does were marked with radio transmitters to monitor movement and survival. Ten additional control deer have been captured and radio-collared for a comparison of fawning rates and survival. Hunters harvested 69 deer in the first hunting season (Fall 2008). In spring 2009, infrared-triggered cameras (IRCs) were used to estimate deer abundance in the sterilization zone, which resulted in a density of 21 deer/km2 (56 deer per square mile). In the hunting zone, deer populations will be monitored using a deer sighting log and by data collected at a mandatory deer check station. In both zones, ongoing deer browse and deer-vehicle accident (OVA) studies will ascertain changes in deer impacts throughout the study. Our goal is to determine if deer fertility control integrated with a controlled hunting program on adjacent lands can maximize the efficiency of both techniques. If this integrated management program is successful, it may have additional applications in other communities in New York State and the Northeast

MDMA (‘ecstasy’) use, and its association with high risk behaviors, mental health, and other factors among gay/bisexual men in New York City

This study assesses patterns of use of methylenedioxymethamphetamine (MDMA or ‘ecstasy’), and the characteristics of users, in a sample of 733 men who have sex with men (MSM) in New York City. Among respondents, 13.7% reported using MDMA in the past 6 months, with mean frequency of use of 6.24 times in that period. MDMA users were found to be younger, less educated, to have had more male partners, more one night stands with men, more visits to bars or clubs and sex clubs or bathhouses, to have unprotected anal sex with a male, to be likely to have been the victim of physical domestic violence, to have more gay/bisexual friends, to have disclosed their sexual orientation to more friends, family members, and coworkers, and to have higher levels of gay community participation and affiliation. Among MDMA users, higher frequency of MDMA use was associated with being younger, having more visits to bars or clubs, more gay/bisexual friends, and having an HIV negative test result or never having been tested. MDMA users thus constitute a group at risk for sexually transmitted diseases, including HIV, and other problems. The data suggest that MDMA use is associated with being more ‘out’, which may be advantageous in helping gay men deal with harmful psychological effects of stigma, but may place individuals in settings that expose them to MDMA. These men have also presumably already been well exposed to safer sex messages within the gay community, thus raising challenges for interventions aimed at prevention, as well as opportunities (e.g. MSM and community specific interventions) that need to be further explored

Bridging the gap -- the disappearance of the intermediate period gap for fully convective stars, uncovered by new ZTF rotation periods

The intermediate period gap, discovered by Kepler, is an observed dearth of stellar rotation periods in the temperature-period diagram at $\sim$ 20 days for G dwarfs and up to $\sim$ 30 days for early-M dwarfs. However, because Kepler mainly targeted solar-like stars, there is a lack of measured periods for M dwarfs, especially those at the fully convective limit. Therefore it is unclear if the intermediate period gap exists for mid- to late-M dwarfs. Here, we present a period catalog containing 40,553 rotation periods (9,535 periods $>$ 10 days), measured using the Zwicky Transient Facility (ZTF). To measure these periods, we developed a simple pipeline that improves directly on the ZTF archival light curves and reduces the photometric scatter by 26%, on average. This new catalog spans a range of stellar temperatures that connect samples from Kepler with MEarth, a ground-based time domain survey of bright M-dwarfs, and reveals that the intermediate period gap closes at the theoretically predicted location of the fully convective boundary ($G_{\rm BP} - G_{\rm RP} \sim 2.45$ mag). This result supports the hypothesis that the gap is caused by core-envelope interactions. Using gyro-kinematic ages, we also find a potential rapid spin-down of stars across this period gap

K2-231 b: A sub-Neptune exoplanet transiting a solar twin in Ruprecht 147

We identify a sub-Neptune exoplanet ($R_p = 2.5 \pm 0.2$ R$_\oplus$) transiting a solar twin in the Ruprecht 147 star cluster (3 Gyr, 300 pc, [Fe/H] = +0.1 dex). The ~81 day light curve for EPIC 219800881 (V = 12.71) from K2 Campaign 7 shows six transits with a period of 13.84 days, a depth of ~0.06%, and a duration of ~4 hours. Based on our analysis of high-resolution MIKE spectra, broadband optical and NIR photometry, the cluster parallax and interstellar reddening, and isochrone models from PARSEC, Dartmouth, and MIST, we estimate the following properties for the host star: $M_\star = 1.01 \pm 0.03$ M$_\odot$, $R_\star= 0.95 \pm 0.03$ R$_\odot$, and $T_{\rm eff} = 5695 \pm 50$ K. This star appears to be single, based on our modeling of the photometry, the low radial velocity variability measured over nearly ten years, and Keck/NIRC2 adaptive optics imaging and aperture-masking interferometry. Applying a probabilistic mass-radius relation, we estimate that the mass of this planet is $M_p = 7 +5 -3$ M$_\oplus$, which would cause a RV semi-amplitude of $K = 2 \pm 1$ m s$^{-1}$ that may be measurable with existing precise RV facilities. After statistically validating this planet with BLENDER, we now designate it K2-231 b, making it the second sub-stellar object to be discovered in Ruprecht 147 and the first planet; it joins the small but growing ranks of 23 other planets found in open clusters.Comment: 24 pages, 7 figures, light curve included as separate fil