Spectral signature of short attosecond pulse trains

We report experimental measurements of high-order harmonic spectra generated in Ar using a carrier-envelope-offset (CEO) stabilized 12 fs, 800nm laser field and a fraction (less than 10%) of its second harmonic. Additional spectral peaks are observed between the harmonic peaks, which are due to interferences between multiple pulses in the train. The position of these peaks varies with the CEO and their number is directly related to the number of pulses in the train. An analytical model, as well as numerical simulations, support our interpretation

Mainstreaming the Animal in Biodiversity Governance: Broadening the Moral and Legal Community to Nonhumans

The individual animal has often been neglected in biodiversity governance debates, with animals mainly considered in terms of species, biodiversity, wildlife or natural resources. Indeed, and somewhat counterintuitively, biodiversity governance is not always animal-friendly. Think, for example, of the issues of wildlife management, (“sport”) hunting, captive breeding, reintroduction and relocation of endangered species, and the use of animal testing in conservation research (De Mori, 2019). For some issues, the relationship is more complex, for example the “management” of Invasive Alien Species (IAS), which is detrimental to the individuals of the species considered “invasive” but beneficial to native species and habitats (Barkham, 2020). Elsewhere, economic development and incentives impact both biodiversity and animal concerns, such as the negative effects of animal agriculture (see Visseren-Hamakers, 2018a; 2020 for more detailed overviews of these relationships). How can we transform biodiversity governance in order to incorporate individual animal interests (Bernstein, 2015)? That is the central question of this chapter

High harmonic generation in a gas-filled hollow-core photonic crystal fiber

High harmonic generation (HHG) of intense infrared laser radiation (Ferray et al., J. Phys. B: At. Mol. Opt. Phys. 21:L31, 1988; McPherson et al., J. Opt. Soc. Am. B 4:595, 1987) enables coherent vacuum-UV (VUV) to soft-X-ray sources. In the usual setup, energetic femtosecond laser pulses are strongly focused into a gas jet, restricting the interaction length to the Rayleigh range of the focus. The average photon flux is limited by the low conversion efficiency and the low average power of the complex laser amplifier systems (Keller, Nature 424:831, 2003; Südmeyer et al., Nat. Photonics 2:599, 2008; Röser et al., Opt. Lett. 30:2754, 2005; Eidam et al., IEEE J. Sel. Top. Quantum Electron. 15:187, 2009) which typically operate at kilohertz repetition rates. This represents a severe limitation for many experiments using the harmonic radiation in fields such as metrology or high-resolution imaging. Driving HHG with novel high-power diode-pumped multi-megahertz laser systems has the potential to significantly increase the average photon flux. However, the higher average power comes at the expense of lower pulse energies because the repetition rate is increased by more than a thousand times, and efficient HHG is not possible in the usual geometry. So far, two promising techniques for HHG at lower pulse energies were developed: external build-up cavities (Gohle et al., Nature 436:234, 2005; Jones et al., Phys. Rev. Lett. 94:193, 2005) and resonant field enhancement in nanostructured targets (Kim et al., Nature 453:757, 2008). Here we present a third technique, which has advantages in terms of ease of HHG light extraction, transverse beam quality, and the possibility to substantially increase conversion efficiency by phase-matching (Paul et al., Nature 421:51, 2003; Ren et al., Opt. Express 16:17052, 2008; Serebryannikov et al., Phys. Rev. E (Stat. Nonlinear Soft Matter Phys.) 70:66611, 2004; Serebryannikov et al., Opt. Lett. 33:977, 2008; Zhang et al., Nat. Phys. 3:270, 2007). The interaction between the laser pulses and the gas occurs in a Kagome-type Hollow-Core Photonic Crystal Fiber (HC-PCF) (Benabid et al., Science 298:399, 2002), which reduces the detection threshold for HHG to only 200nJ. This novel type of fiber guides nearly all of the light in the hollow core (Couny et al., Science 318:1118, 2007), preventing damage even at intensities required for HHG. Our fiber guided 30-fs pulses with a pulse energy of more than 10μJ, which is more than five times higher than for any other photonic crystal fiber (Hensley et al., Conference on Lasers and Electro-Optics (CLEO), IEEE Press, New York, 2008

Enabling transformative biodiversity governance in the Post-2020 era

While there are increasing calls for transformative change and transformative governance, what this means in the context of addressing biodiversity loss remains debated. The aim of this edited volume Transforming Biodiversity Governance is to open up this debate and identify ways forward in the context of the implementation of the Post-2020 Global Biodiversity Framework (GBF) of the Convention on Biological Diversity (CBD). To become transformative, biodiversity governance needs to be transformed: yet how and by whom? These questions are urgent, given the fact that around one million species are threatened with extinction (Díaz et al., 2019), despite over half a century of global efforts to avoid this tragedy. By bringing together insights from previous chapters, we here reflect on these questions

Enabling Transformative Biodiversity Governance in the post-2020 Era

While there are increasing calls for transformative change and transformative governance, what this means in the context of addressing biodiversity loss remains debated. The aim of this edited volume Transforming Biodiversity Governance is to open up this debate and identify ways forward in the context of the implementation of the Post-2020 Global Biodiversity Framework (GBF) of the Convention on Biological Diversity (CBD). To become transformative, biodiversity governance needs to be transformed: yet how and by whom? These questions are urgent, given the fact that around one million species are threatened with extinction (Díaz et al., 2019), despite over half a century of global efforts to avoid this tragedy

Mutation Size Optimizes Speciation in an Evolutionary Model

The role of mutation rate in optimizing key features of evolutionary dynamics has recently been investigated in various computational models. Here, we address the related question of how maximum mutation size affects the formation of species in a simple computational evolutionary model. We find that the number of species is maximized for intermediate values of a mutation size parameter μ; the result is observed for evolving organisms on a randomly changing landscape as well as in a version of the model where negative feedback exists between the local population size and the fitness provided by the landscape. The same result is observed for various distributions of mutation values within the limits set by μ. When organisms with various values of μ compete against each other, those with intermediate μ values are found to survive. The surviving values of μ from these competition simulations, however, do not necessarily coincide with the values that maximize the number of species. These results suggest that various complex factors are involved in determining optimal mutation parameters for any population, and may also suggest approaches for building a computational bridge between the (micro) dynamics of mutations at the level of individual organisms and (macro) evolutionary dynamics at the species level

Consumerisation in UK Higher Education Business Schools: Higher fees, greater stress and debatable outcomes

For many UK Higher Education Business Schools, the continued recruitment of UK, EU and International students is crucial for financial stability, viability and independence. Due to increasingly competitive funding models across the sector many institutional leaders and administrators are making decisions typical of highly marketised consumer environments. Thus, this paper explores, academics’ perceptions of the impact of consumerisation in UK Higher Education Business Schools. To achieve this 22 Business School academics were interviewed within three UK Higher Education institutions (HEIs) in the North of England. Participants had a minimum of three years teaching experience. Data was analysed using template analysis taking an interpretive approach. The findings indicate that academics perceived the introduction of tuition fees to have been the catalyst for students increasing demonstration of customer-like behaviour: viewing the education process as transactional, with the HEI providing a ‘paid for’ service. It is argued that these changes in UK Higher Education have created tensions between university leaders and academics, creating genuine dilemmas for those with decision-making responsibilities who must balance academic integrity and long term institutional financial viability