Conservation of Arabidopsis thaliana photoperiodic flowering time genes in onion (Allium cepa L.)

The genetics underlying onion development is poorly understood. Here the characterisation of onion homologues of Arabidopsis photoperiodic flowering pathway genes is reported with the end goal of accelerating onion breeding programmes by understanding the genetic basis of adaptation to different latitudes. The expression of onion GI, FKF1 and ZTL homologues under SD and LD conditions was examined using quantitative RT-PCR. The expression of AcGI and AcFKF1 was examined in onion varieties which exhibit different daylength responses. Phylogenetic trees were constructed to confirm the identity of the homologues. AcGI and AcFKF1 showed diurnal expression patterns similar to their Arabidopsis counterparts while AcZTL was found to be constitutively expressed. AcGI showed similar expression patterns in varieties which exhibit different daylength responses whereas AcFKF1 showed differences. It is proposed that these differences could contribute to the different daylength responses in these varieties. Phylogenetic analyses showed that all the genes isolated are very closely related to their proposed homologues. The results presented here show that key genes controlling photoperiodic flowering in Arabidopsis are conserved in onion and a role for these genes in the photoperiodic control of bulb initiation is predicted. This theory is supported by expression and phylogenetic data

Managing Option Fragility

We analyze and explore option fragility, the notion that option incentives are fragile due to their non-linear payoff structure. Option incentives become weaker as options fall underwater, leading to pressures to reprice options or restore incentives through additional grants of equity-based pay. We build a detailed data set on executives' portfolios of stock and options and find that executive options are frequently underwater, even when average stock returns have been high. For example, at the height of the bull market in 1999, approximately one-third of all executive options were underwater. We find that, in contrast to the incentives provided by stock, the incentives provided by options are quite sensitive to stock price changes, especially on the downside. Overall, we find that the incentives created by all executive holdings have an elasticity with respect to stock price decreases of about 0.7, and this elasticity is larger for high-option executives and for executives with high percentages of options already underwater. The dominant mechanism through which companies manage option fragility is larger option grants following stock price declines; on average, these larger grants restore approximately 40% of the stock-price-induced incentive declines. Option repricings are far less prevalent, despite the attention they have garnered. Interestingly, we find that for positive stock returns, higher returns lead to larger option grants, which raise incentives further. Thus, option grants are largest when companies do very poorly or very well. Executive exercising behavior also affects option fragility. Since executives are much less likely to exercise options following stock price decreases, the natural declines in incentives due to exercises are attenuated on the downside, leading executives to 'manage their own incentives' in a way that augments company management of option fragility.

Large Scale Anisotropy of Cosmic Rays and Directional Neutrino Signals from Galactic Sources

We investigate the neutrino - cosmic ray connection for sources in the Galaxy in terms of two observables: the shape of the energy spectrum and the distribution of arrival directions. We also study the associated gamma ray emission from these sources.Comment: Proceedings of the 2nd Cosmic Ray Anisotropy Workshop, 26-28 September 2013, Madison, Wisconsin. To appear in IOP Conference Serie

Superluminous supernovae: No threat from Eta Carinae

Recently Supernova 2006gy was noted as the most luminous ever recorded, with a total radiated energy of ~10^44 Joules. It was proposed that the progenitor may have been a massive evolved star similar to eta Carinae, which resides in our own galaxy at a distance of about 2.3 kpc. eta Carinae appears ready to detonate. Although it is too distant to pose a serious threat as a normal supernova, and given its rotation axis is unlikely to produce a Gamma-Ray Burst oriented toward the Earth, eta Carinae is about 30,000 times nearer than 2006gy, and we re-evaluate it as a potential superluminous supernova. We find that given the large ratio of emission in the optical to the X-ray, atmospheric effects are negligible. Ionization of the atmosphere and concomitant ozone depletion are unlikely to be important. Any cosmic ray effects should be spread out over ~10^4 y, and similarly unlikely to produce any serious perturbation to the biosphere. We also discuss a new possible effect of supernovae, endocrine disruption induced by blue light near the peak of the optical spectrum. This is a possibility for nearby supernovae at distances too large to be considered "dangerous" for other reasons. However, due to reddening and extinction by the interstellar medium, eta Carinae is unlikely to trigger such effects to any significant degree.Comment: 19 pages, 2 figures; Revised version as accepted for publication in Astrobiolog

Picosecond time-resolved pure-rotational coherent anti-Stokes Raman spectroscopy for N-2 thermometry

This paper was published in Optics Letters and is made available as an electronic reprint with the permission of OSA. The paper can be found at the following URL on the OSA website: http://www.opticsinfobase.org/abstract.cfm?URI=ol-34-23-3755. Systematic or multiple reproduction or distribution to multiple locations via electronic or other means is prohibited and is subject to penalties under law.Peer reviewedPublisher PD

Dampening prey cycle overrides the impact of climate change on predator population dynamics : a long-term demographic study on tawny owls

Funded by ERA-Net BiodivERsA NERC. Grant Numbers: NE/E010660/1, NE/F021402/1, NE/G002045/1Peer reviewedPublisher PD