17 research outputs found

    SAIL Panama Canal Zone Project 2008 : Biological Survey of Panama (1910-1912)

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    During the 18th Annual 2008 SAIL meeting at the Smithsonian Tropical Research Institute in Panama, a suggestion was made for the need to digitize and make available through the Aquatic Commons some of the early documents related to the U.S. biological survey of Panama from 1910 to 1912. With SAIL’s endeavor, a new digital project was born and this presentation describes its process, beginning to final product. The main source consulted for determining copyright clear publications was: Heckadon-Moreno. 2004. Naturalists on the Isthmus of Panama: A hundred years of natural history on the biological bridge of the Americas. 1st English ed. Smithsonian Tropical Research Institute, Panama City, Republic of Panama. (Document contains 26 slides

    Notes on Dynamics of an External Cavity Semiconductor Lasers

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    Dynamics of external cavity semiconductor lasers is known to be a complex and uncontrollable phenomenon. Due to the lack of experimental studies on the nature of the external cavity semiconductor lasers, there is a need to theoretically clarify laser dynamics. The stability of laser dynamics in the present paper, is analyzed through plotting the Lyapunov exponent spectra, bifurcation diagrams, phase portrait and electric field intensity time series. The analysis is preformed with respect to applied feedback phase CpC_p, feedback strength η\eta and the pump current of the laser. The main argument of the paper is to show that the laser dynamics can not be accounted for through simply a bifurcation diagram and single-control parameter. The comparison of the obtained results provides a very detailed picture of the qualitative changes in laser dynamics.Comment: 7 pages, 34 figure

    The state of the Martian climate

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    60°N was +2.0°C, relative to the 1981–2010 average value (Fig. 5.1). This marks a new high for the record. The average annual surface air temperature (SAT) anomaly for 2016 for land stations north of starting in 1900, and is a significant increase over the previous highest value of +1.2°C, which was observed in 2007, 2011, and 2015. Average global annual temperatures also showed record values in 2015 and 2016. Currently, the Arctic is warming at more than twice the rate of lower latitudes

    Chronostratigraphy and age modeling of Pleistocene drill cores from the Olduvai Basin, Tanzania (Olduvai Gorge Coring Project)

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    The Olduvai Gorge Coring Project drilled a total of 611.72 m of core (575.48 m recovered) of mostly fluvio-lacustrine and fan-delta volcaniclastic Pleistocene strata at three sites in the Olduvai Basin, Tanzania, in 2014. We have developed a chronostratigraphic framework for three of the cores based on 40Ar/39Ar dating of core and outcrop volcanic and volcaniclastic units, core paleomagnetic stratigraphy, and tephrochemical correlation between cores and from core to outcrop. This framework is then used to constrain Bayesian stratigraphic age models which permit age estimates for desired core levels with realistic confidence intervals. The age models reveal that the deepest core level reached at 245 mbs is ~2.24 Ma, ~210 kyr older than the oldest strata exposed at Olduvai Gorge. Strata net accretion rates in this early phase of basin history were relatively rapid (57–69 cm/kyr), but decreased within ~250 kyr to ~15 cm/kyr in Lower Bed I. Rates rebounded partially in Upper Bed I, but subsequently declined to \u3c10 cm/kyr by Middle to Upper Pleistocene. The age models also provide new estimates for the basal contacts of upper Olduvai Gorge stratigraphic units that have been previously difficult to calibrate: Bed III at 1.14 ± 0.05 (95% confidence interval), Bed IV at 0.93 ± 0.08, Masek at 0.82 ± 0.06, and Ndutu at 0.50 ± 0.04 Ma. Finally, based on recently acquired seismic imaging identifying basement another 135 m beneath the bottom of the deepest core, extrapolation of net accretion rates suggests that sedimentation began at this site in the Olduvai Basin at ~2.5 Ma
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