Shrike predation on the lizard Mesalina adramitana in Qatar; a review of reported reptile and amphibian prey

We report, for the first time, evidence of predation by a shrike (Lanius sp.) on the lizard Mesalina adramitana. This is the first record of predation by shrikes on lizards in Qatar. Whilst we did not directly observe the event, the presence of shrikes in the area and the method of impalement indicate shrikes as the predator. The lizard was found freshly impaled on a palm tree (Phoenix dactylifera), at 150 cm above ground. Bird species of the genus Lanius are well-known predators of lizards, and in arid environments reptiles are likely common prey for these birds. We provide a review of literature concerning predatory events by shrikes on reptiles and amphibians. We suggest inspection of shrubs for animals impaled by shrikes can improve biodiversity inventories, complementing other commonly used methods

The Gravitational Universe

The last century has seen enormous progress in our understanding of the Universe. We know the life cycles of stars, the structure of galaxies, the remnants of the big bang, and have a general understanding of how the Universe evolved. We have come remarkably far using electromagnetic radiation as our tool for observing the Universe. However, gravity is the engine behind many of the processes in the Universe, and much of its action is dark. Opening a gravitational window on the Universe will let us go further than any alternative. Gravity has its own messenger: Gravitational waves, ripples in the fabric of spacetime. They travel essentially undisturbed and let us peer deep into the formation of the first seed black holes, exploring redshifts as large as z ~ 20, prior to the epoch of cosmic re-ionisation. Exquisite and unprecedented measurements of black hole masses and spins will make it possible to trace the history of black holes across all stages of galaxy evolution, and at the same time constrain any deviation from the Kerr metric of General Relativity. eLISA will be the first ever mission to study the entire Universe with gravitational waves. eLISA is an all-sky monitor and will offer a wide view of a dynamic cosmos using gravitational waves as new and unique messengers to unveil The Gravitational Universe. It provides the closest ever view of the early processes at TeV energies, has guaranteed sources in the form of verification binaries in the Milky Way, and can probe the entire Universe, from its smallest scales around singularities and black holes, all the way to cosmological dimensions

Methods for simulating the readout of lengths and angles in laser interferometers with Gaussian beams

In this paper methods to simulate the signals in laser interferometers are proposed. The central part deals with the computation of the photocurrent, subsequent phase demodulation and finally the generation of interferometer signals, such as the longitudinal phase readout, differential wavefront sensing signal, differential power sensing and contrast. Here, fundamental Gaussian beams without astigmatism are assumed. The methods are validated in several examples by comparison with experimental data, with analytical results as well as with an intuitively predictable system

Simulating and Optimizing Laser Interferometers

This paper introduces the IFOCAD software which is designed to simulate laser interferometers using different beam models, including non-astigmatic as well as simple and general astigmatic Gaussian beams in the fundamental mode. With IFOCAD it is also possible to compute heterodyne signals such as pathlength signal, differential wavefront sensing signal, differential power sensing signal and contrast. Another important feature of IFOCAD are optimization algorithms that are useful for designing laser interferometers and adjusting them to fulfill specific requirements

Laser link acquisition demonstration for the GRACE Follow-On mission

We experimentally demonstrate an inter-satellite laser link acquisition scheme for GRACE Follow-On. In this strategy, dedicated acquisition sensors are not required-instead we use the photodetectors and signal processing hardware already required for science operation. To establish the laser link, a search over five degrees of freedom must be conducted (± 3 mrad in pitch/yaw for each laser beam, and ± 1 GHz for the frequency difference between the two lasers). This search is combined with a FFT-based peak detection algorithm run on each satellite to find the heterodyne beat note resulting when the two beams are interfered. We experimentally demonstrate the two stages of our acquisition strategy: a ± 3 mrad commissioning scan and a ± 300 μrad reacquisition scan. The commissioning scan enables each beam to be pointed at the other satellite to within 142 μrad of its best alignment point with a frequency difference between lasers of less than 20 MHz. Scanning over the 4 alignment degrees of freedom in our commissioning scan takes 214 seconds, and when combined with sweeping the laser frequency difference at a rate of 88 kHz/s, the entire commissioning sequence completes within 6.3 hours. The reacquisition sequence takes 7 seconds to complete, and optimizes the alignment between beams to allow a smooth transition to differential wavefront sensing-based auto-alignment.This work was supported in part under the Australian Government’s Australian Space Research Programme, grants from the Australian Research Council, and by the “Deutsche Forschungsgemeinschaft” (DFG) through the Cluster of Excellence QUEST (Centre for Quantum Engineering and Space-Time Research)

Synopsis and taxonomic revision of three genera in the snake tribe Sonorini

Cox, Christian L., Davis Rabosky, Alison R., Holmes, Iris A., Reyes-Velasco, Jacobo, Roelke, Corey E., Smith, Eric N., Flores-Villela, Oscar, McGuire, Jimmy A., Campbell, Jonathan A. (2018): Synopsis and taxonomic revision of three genera in the snake tribe Sonorini. Journal of Natural History 52 (13-16): 945-988, DOI: 10.1080/00222933.2018.1449912, URL: http://dx.doi.org/10.1080/00222933.2018.144991