Thar She Blows! A Novel Method for DNA Collection from Cetacean Blow

Background: Molecular tools are now widely used to address crucial management and conservation questions. To date, dart biopsying has been the most commonly used method for collecting genetic data from cetaceans; however, this method has some drawbacks. Dart biopsying is considered inappropriate for young animals and has recently come under scrutiny from ethical boards, conservationists, and the general public. Thus, identifying alternative genetic collection techniques for cetaceans remains a priority, especially for internationally protected species. Methodology/Principal Findings: In this study, we investigated whether blow-sampling, which involves collecting exhalations from the blowholes of cetaceans, could be developed as a new less invasive method for DNA collection. Our current methodology was developed using six bottlenose dolphins, Tursiops truncatus, housed at the National Aquarium, Baltimore (USA), from which we were able to collect both blow and blood samples. For all six individuals, we found that their mitochondrial and microsatellite DNA profile taken from blow, matched their corresponding mitochondrial and microsatellite DNA profile collected from blood. This indicates that blow-sampling is a viable alternative method for DNA collection. Conclusion/Significance: In this study, we show that blow-sampling provides a viable and less invasive method for collection of genetic data, even for small cetaceans. In contrast to dart biopsying, the advantage of this method is that it capitalizes on the natural breathing behaviour of dolphins and can be applied to even very young dolphins. Both biopsy and blow-sampling require close proximity of the boat, but blow-sampling can be achieved when dolphins voluntarily bowride and involves no harmful contact

Digital reconstruction of the inner ear of Leptictidium auderiense (Leptictida, Mammalia) and North American leptictids reveals new insight into leptictidan locomotor agility

Leptictida are basal Paleocene to Oligocene eutherians from Europe and North America comprising species with highly specialized postcranial features including elongated hind limbs. Among them, the European Leptictidium was probably a bipedal runner or jumper. Because the semicircular canals of the inner ear are involved in detecting angular acceleration of the head, their morphometry can be used as a proxy to elucidate the agility in fossil mammals. Here we provide the first insight into inner ear anatomy and morphometry of Leptictida based on high-resolution computed tomography of a new specimen of Leptictidium auderiense from the middle Eocene Messel Pit (Germany) and specimens of the North American Leptictis and Palaeictops. The general morphology of the bony labyrinth reveals several plesiomorphic mammalian features, such as a secondary crus commune. Leptictidium is derived from the leptictidan groundplan in lacking the secondary bony lamina and having proportionally larger semicircular canals than the leptictids under study. Our estimations reveal that Leptictidium was a very agile animal with agility score values (4.6 and 5.5, respectively) comparable to Macroscelidea and extant bipedal saltatory placentals. Leptictis and Palaeictops have lower agility scores (3.4 to 4.1), which correspond to the more generalized types of locomotion (e.g., terrestrial, cursorial) of most extant mammals. In contrast, the angular velocity magnitude predicted from semicircular canal angles supports a conflicting pattern of agility among leptictidans, but the significance of these differences might be challenged when more is known about intraspecific variation and the pattern of semicircular canal angles in non-primate mammals

The effects of Δ9-tetrahydrocannabinol on the dopamine system

Δ(9)-tetrahydrocannabinol (THC), the main psychoactive ingredient in cannabis, is a pressing concern to global mental health. Patterns of use are changing drastically due to legalisation, availability of synthetic analogues (‘spice’), cannavaping and aggrandizements in the purported therapeutic effects of cannabis. Many of THC’s reinforcing effects are mediated by the dopamine system. Due to complex cannabinoid-dopamine interactions there is conflicting evidence from human and animal research fields. Acute THC causes increased dopamine release and neuron activity, whilst long-term use is associated with blunting of the dopamine system. Future research must examine the long-term and developmental dopaminergic effects of the drug

Pseudoresonant laser wakefield acceleration driven by 10.6-μm laser light

This paper describes an experiment to demonstrate, for the first time, laser wakefield acceleration (LWFA), driven by 10.6-μm light from a CO2 laser. This experiment is also noteworthy because it will operate in a pseudoresonant LWFA regime, in which the laser-pulse-length is too long for resonant LWFA, but too short for self-modulated LWFA. Nonetheless, high acceleration gradients are still possible. This experiment builds upon an earlier experiment called staged electron laser acceleration (STELLA), where efficient trapping and monoenergetic laser acceleration of electrons were demonstrated using inverse free electron lasers. The aim is to apply the STELLA approach of laser-driven microbunch formation followed by laser-driven trapping and acceleration to LWFA. These capabilities are important for a practical electron linear accelerator based upon LWFA. © 2005 IEEE

Inverse free electron lasers and laser wakefield acceleration driven by CO2 lasers.

The staged electron laser acceleration (STELLA) experiment demonstrated staging between two laser-driven devices, high trapping efficiency of microbunches within the accelerating field and narrow energy spread during laser acceleration. These are important for practical laser-driven accelerators. STELLA used inverse free electron lasers, which were chosen primarily for convenience. Nevertheless, the STELLA approach can be applied to other laser acceleration methods, in particular, laser-driven plasma accelerators. STELLA is now conducting experiments on laser wakefield acceleration (LWFA). Two novel LWFA approaches are being investigated. In the first one, called pseudo-resonant LWFA, a laser pulse enters a low-density plasma where nonlinear laser/plasma interactions cause the laser pulse shape to steepen, thereby creating strong wakefields. A witness e-beam pulse probes the wakefields. The second one, called seeded self-modulated LWFA, involves sending a seed e-beam pulse into the plasma to initiate wakefield formation. These wakefields are amplified by a laser pulse following shortly after the seed pulse. A second e-beam pulse (witness) follows the seed pulse to probe the wakefields. These LWFA experiments will also be the first ones driven by a CO(2) laser beam

Update on seeded SM-LWFA and pseudo-resonant LWFA experiments - (STELLA-LW)

The Staged Electron Laser Acceleration - Laser Wakefield (STELLA-LW) experiment is investigating two new methods for laser wakefield acceleration (LWFA) using the TW CO2 laser available at the Brookhaven National Laboratory Accelerator Test Facility. The first is seeded self-modulated LWFA where an ultrashort electron bunch (seed) precedes the laser pulse to generate a wakefield that the laser pulse subsequently amplifies. The second is pseudo-resonant LWFA where nonlinear pulse steepening of the laser pulse occurs in the plasma allowing the laser pulse to generate significant wakefields. The status of these experiments is reviewed. Evidence of wakefield generation caused by the seed bunches has been obtained as well as preliminary energy gain measurements of a witness bunch following the seeds. Comparison with a 1-D linear model for the wakefield generation appears to agree with the data. © 2006 American Institute of Physics