Foraging Behavior of Spring Bees and Their Agricultural Implications

Colony Collapse Disorder has greatly reduced honey bee populations in the last decade. Native bees have been largely neglected in research, and their floral preferences may have agricultural implications because native bees ameliorate the demand to rely solely on non-native bees. In this work, pollinator visitation to flowers with manipulated ultraviolet floral patterns was monitored. Populations of wild showy golden-eye in Colorado, plus cultivar populations of black-eyed Susan and lawn populations of buttercups in Virginia were monitored for pollinator landings to compare preference for unmanipulated ultraviolet-absorptive floral guide preferences. Another number, a proxy for pollen load, was manipulated on strawberry flowers to determine whether this treatment affected mason bee visitation frequency. Three mason bee densities (three, six and nine bees in ≈2.33 m2) were compared in three greenhouses, each stocked with 10 strawberry plants. Bee visitations were monitored and berry size and symmetry were measured. Mason bee emergence rates were compared in two environments (natural conditions and temperature-controlled conditions) for cocoons. Field surveys was conducted to evaluate which native pollinators naturally recruited to field blackberries. Higher visitation rates were found for flowers with larger ultraviolet-absorptive floral guides and stamen manipulations. Mason bees did visit flowers but did not demonstrate any preference for flowers with more stamen. Bee density did not affect berry weight or berry symmetry. High emergence rates were observed in both natural and controlled environments and more bees emerged in the controlled environment. Sweat bees and bumble bees were the major visitors to blackberry flowers but honey bees were not present. This work builds upon earlier findings that pollinators prefer larger ultraviolet patterns and supports a more generalizable phenomenon. This study further suggests that mason bees may be commercially valuable given their peak of in mid-summer, coinciding with the pollination period of fruiting crops. Native pollinators may play an important role in blackberry pollination because of their relatively high abundance relative to honey bees

A flow equation approach to periodically driven quantum systems

We present a theoretical method to generate a highly accurate {\em time-independent} Hamiltonian governing the finite-time behavior of a time-periodic system. The method exploits infinitesimal unitary transformation steps, from which renormalization group-like flow equations are derived to produce the effective Hamiltonian. Our tractable method has a range of validity reaching into frequency regimes that are usually inaccessible via high frequency $\omega$ expansions in the parameter $h/\omega$, where $h$ is the upper limit for the strength of local interactions. We demonstrate our approach on both interacting and non-interacting many-body Hamiltonians where it offers an improvement over the more well-known Magnus expansion and other high frequency expansions. For the interacting models, we compare our approximate results to those found via exact diagonalization. While the approximation generally performs better globally than other high frequency approximations, the improvement is especially pronounced in the regime of lower frequencies and strong external driving. This regime is of special interest because of its proximity to the resonant regime where the effect of a periodic drive is the most dramatic. Our results open a new route towards identifying novel non-equilibrium regimes and behaviors in driven quantum many-particle systems.Comment: 25 pages, 14 figure

Stellar Activity and its Implications for Exoplanet Detection on GJ 176

We present an in-depth analysis of stellar activity and its effects on radial velocity (RV) for the M2 dwarf GJ 176 based on spectra taken over 10 years from the High Resolution Spectrograph on the Hobby-Eberly Telescope. These data are supplemented with spectra from previous observations with the HIRES and HARPS spectrographs, and V- and R-band photometry taken over 6 years at the Dyer and Fairborn observatories. Previous studies of GJ 176 revealed a super-Earth exoplanet in an 8.8-day orbit. However, the velocities of this star are also known to be contaminated by activity, particularly at the 39-day stellar rotation period. We have examined the magnetic activity of GJ 176 using the sodium I D lines, which have been shown to be a sensitive activity tracer in cool stars. In addition to rotational modulation, we see evidence of a long-term trend in our Na I D index, which may be part of a long-period activity cycle. The sodium index is well correlated with our RVs, and we show that this activity trend drives a corresponding slope in RV. Interestingly, the rotation signal remains in phase in photometry, but not in the spectral activity indicators. We interpret this phenomenon as the result of one or more large spot complexes or active regions which dominate the photometric variability, while the spectral indices are driven by the overall magnetic activity across the stellar surface. In light of these results, we discuss the potential for correcting activity signals in the RVs of M dwarfs.Comment: Accepted for publication in Ap

Internal Audit, Sarbanes-Oxley And Athletic Departments: An Examination And Recommendations For Reform

During the past fifteen to twenty years the integrity of intercollegiate athletics has been seriously questioned as a result of an increased awareness of problems associated with institutional controls over athletic departments.  Limited empirical evidence has been used in the debate regarding institutional controls pertaining to the athletic department.  This paper provides empirical evidence regarding the use of the internal audit function as an institutional control.  Our findings indicate that while the internal audits of athletic departments are adequate, the communication of these audit results is inadequate.  We also discuss the applicability of recent legislation, Sarbanes-Oxley Act of 2002, to colleges and universities.  Recommendations to enhance institutional controls regarding intercollegiate athletics are provided.

CHARACTERISTICS OF MANGROVE DIAMONDBACK TERRAPINS (MALACLEMYS TERRAPIN RHIZOPHORARUM) INHABITING ALTERED AND NATURAL MANGROVE ISLANDS

The Mangrove Diamondback Terrapin, (Malaclemys terrapin rhizophorarum) is dependent on a very broad array of the services provided by the mangrove ecosystem. We sought to evaluate both the turtles and their habitat by an integrated assessment of physical, chemical, and physiological parameters. Extreme site fidelity of the turtles to mangrove habitat was evident along with a strong female biased sex ratio. We provide blood serum values and microbial cultures as baselines from these turtles in the wild. Salmonella sp., a potentially zoonotic pathogen, was isolated from one female. Ultimately, the health of these turtle populations may be reflective of the integrity of the mangrove system on which they depend