555 research outputs found

    Rearrangement of p, p1 Disubstituted Benzils

    Get PDF
    Author Institution: Department of Chemistry, Miami University, Oxford, Ohi

    Nocturnal Copulation in Glaucous-winged Gulls Larus glaucescens

    Get PDF
    Gulls (Laridae) are primarily diurnal, although many species forage opportunistically at night, and several species copulate at night. We used trail cameras to study time-of-day variation in the rate of copulation by Glaucous-winged Gulls Larus glaucescens in a breeding colony (1500+ pairs) at Protection Island, Washington, USA, from 31 May to 07 June 2018. Copulations (n = 353) occurred at a significantly higher rate during the day (0.82/camera-h) than at night (0.51/camera-h), with 76.3 % of copulations during the day and 23.7 % at night (daylight comprised 66.1 % and darkness comprised 33.9 % of the study period). The copulation rate peaked shortly before and after dawn, with a second peak before sunset. Copulation rate was lowest during the middle of the day and middle of the night. Glaucous-winged Gulls sleep intermittently during both day and night and have sufficient energy to sustain sporadic copulations during the night, which appears to be a normal part of their reproductive behavior. The most likely advantage of this pattern is an increased opportunity for fertilization with a mate

    Container shipping in the Great Lakes: current situation and future potential

    Get PDF
    Containerization has had an outsized impact on the growth of global trade over the past 60 years. The Great Lakes-St. Lawrence Seaway is an important bi-national waterway. Since the advent of containerization in the 1950’s there has been much excitement about the prospects of scheduled container shipping in the Great Lakes. There is a perception that direct container service will add value to the economy of the Great Lakes- St. Lawrence Basin (GLSLB). However, due to unique shipping constraints in the Great Lakes-St. Lawrence Seaway, significant container service has not materialized. This research seeks to explain the current state of container shipping in the Great Lakes, as well as provide an analysis of the feasibility of future container shipping in the Great Lakes. It is very important for policymakers to understand both the opportunities for container shipping, and the barriers and issues with such services. A lack of understanding of these points can lead to missed opportunities and/or the potential for significant expenditures of time and money on unrealistic projects

    Influence of epitaxial strain on elastocaloric effect in ferroelectric thin films

    Get PDF
    Y.L., J.W., and B.D. thank the China Scholarship Council (CSC). X.J.L., J.W., Y.L., and B.D. thank the National Science Foundation of China (NSFC Nos. 51272204 and 51372195), the Ministry of Science and Technology of China through a 973-Project (No. 2012CB619401), and “One Thousand Youth Talents” program for support. L.B. thank NSF Grant No. DMR-1066158.We report the influence of epitaxial strain um on the elastocaloric properties of BaTiO3 thin films. Using thermodynamic calculations, we show that there exists a critical compressive stress   σ3c at which the elastocaloric effect is maximized for any compressive misfit strain we investigate. Moreover, it is found that |σ3c| decreases significantly with decreasing |um| , which is accompanied by a reduction of the elastocaloric response. Interestingly, a several fold enhancement in the electrocaloric effect can be achieved for stress in proximity of σ3c . The elastocaloric effect predicted here may find potential cooling applications by combining the stress-mediated electrocaloric effect or designing hybrid elastocaloric/electrocaloric devices in the future.Publisher PDFPeer reviewe

    Development of a telescope for medium-energy gamma-ray astronomy

    Get PDF
    The Advanced Energetic Pair Telescope (AdEPT) is being developed at GSFC as a future NASA MIDEX mission to explore the medium-energy (5–200 MeV) gamma-ray range. The enabling technology for AdEPT is the Three- Dimensional Track Imager (3-DTI), a gaseous time projection chamber. The high spatial resolution 3-D electron tracking of 3-DTI enables AdEPT to achieve high angular resolution gamma-ray imaging via pair production and triplet production (pair production on electrons) in the medium-energy range. The low density and high spatial resolution of 3-DTI allows the electron positron track directions to be measured before they are dominated by Coulomb scattering. Further, the significant reduction of Coulomb scattering allows AdEPT to be the first medium-energy gamma-ray telescope to have high gamma-ray polarization sensitivity. We review the science goals that can be addressed with a medium-energy pair telescope, how these goals drive the telescope design, and the realization of this design with AdEPT. The AdEPT telescope for a future MIDEX mission is envisioned as a 8 m3 active volume filled with argon at 2 atm. The design and performance of the 3-DTI detectors for the AdEPT telescope are described as well as the outstanding instrument challenges that need to be met for the AdEPT mission

    Tus, an E. coli Protein, Contains Mammalian Nuclear Targeting and Exporting Signals

    Get PDF
    Shuttling of proteins between nucleus and cytoplasm in mammalian cells is facilitated by the presence of nuclear localization signals (NLS) and nuclear export signals (NES), respectively. However, we have found that Tus, an E. coli replication fork arresting protein, contains separate sequences that function efficiently as NLS and NES in mammalian cell lines, as judged by cellular location of GFP-fusion proteins. The NLS was localized to a short stretch of 9 amino acids in the carboxy-terminus of Tus protein. Alterations of any of these basic amino acids almost completely abolished the nuclear targeting. The NES comprises a cluster of leucine/hydrophobic residues located within 21 amino acids at the amino terminus of Tus. Finally, we have shown that purified GFP-Tus fusion protein or GFP-Tus NLS fusion protein, when added to the culture media, was internalized very efficiently into mammalian cells. Thus, Tus is perhaps the first reported bacterial protein to possess both NLS and NES, and has the capability to transduce protein into mammalian cells
    corecore