Efficient loading of a He* magneto-optic trap using a liquid He cooled source

We report loading large numbers (up to 3×10⁹) of metastable triplet helium atoms into a magneto-optical trap using an atomic beam derived from a liquid He (LHe) cooled dc discharge source. Moreover, we compare the effect of liquidN₂ cooling to LHe cooling the source and demonstrate that LHe cooling offers a significant increase in performance

Beyond skills: embodying writerly practices through the doctorate

Summary: This article explores the features and potential of an embodied, rather than merely skills based, approach to doctoral writing. Our conceptual framework is derived from the phenomenological literature, particularly Heidegger's critique of modern life as permeated by a quest for mastery and control. We address two key questions with respect to this: Firstly, what role might the quest for mastery as achieving command or control play in impeding writing and undermining an embodied writerly practice? Secondly, to what extent might narrow skills based approaches to writing unwittingly promote the quest for mastery and therefore encourage, rather than diminish, the anxieties that doctoral research writers may feel

Paired atom laser beams created via four-wave mixing

A method to create paired atom laser beams from a metastable helium atom laser via four-wave mixing is demonstrated. Radio frequency outcoupling is used to extract atoms from a Bose Einstein condensate near the center of the condensate and initiate scattering between trapped and untrapped atoms. The unequal strengths of the interactions for different internal states allows an energy-momentum resonance which leads to the creation of pairs of atoms scattered from the zero-velocity condensate. The resulting scattered beams are well separated from the main atom laser in the 2-dimensional transverse atom laser profile. Numerical simulations of the system are in good agreement with the observed atom laser spatial profiles, and indicate that the scattered beams are generated by a four-wave mixing process, suggesting that the beams are correlated.Comment: 5 pages, 3 figure

Habitat stability, predation risk and 'memory syndromes'

ArticleThis is the author's accepted version. The article has been published Open Access and is available at http://www.nature.com/srep/2015/150527/srep10538/full/srep10538.htmlCopyright © 2015 Macmillan Publishers Limited. All Rights Reserved.Habitat stability and predation pressure are thought to be major drivers in the evolutionary maintenance of behavioural syndromes, with trait covariance only occurring within specific habitats. However, animals also exhibit behavioural plasticity, often through memory formation. Memory formation across traits may be linked, with covariance in memory traits (memory syndromes) selected under particular environmental conditions. This study tests whether the pond snail, Lymnaea stagnalis, demonstrates consistency among memory traits (‘memory syndrome’) related to threat avoidance and foraging. We used eight populations originating from three different habitat types: i) laboratory populations (stable habitat, predator-free); ii) river populations (fairly stable habitat, fish predation); and iii) ditch populations (unstable habitat, invertebrate predation). At a population level, there was a negative relationship between memories related to threat avoidance and food selectivity, but no consistency within habitat type. At an individual level, covariance between memory traits was dependent on habitat. Laboratory populations showed no covariance among memory traits, whereas river populations showed a positive correlation between food memories, and ditch populations demonstrated a negative relationship between threat memory and food memories. Therefore, selection pressures among habitats appear to act independently on memory trait covariation at an individual level and the average response within a population.Leverhulme Trus

The amplitude of solar oscillations using stellar techniques

The amplitudes of solar-like oscillations depend on the excitation and damping, both of which are controlled by convection. Comparing observations with theory should therefore improve our understanding of the underlying physics. However, theoretical models invariably compute oscillation amplitudes relative to the Sun, and it is therefore vital to have a good calibration of the solar amplitude using stellar techniques. We have used daytime spectra of the Sun, obtained with HARPS and UCLES, to measure the solar oscillations and made a detailed comparison with observations using the BiSON helioseismology instrument. We find that the mean solar amplitude measured using stellar techniques, averaged over one full solar cycle, is 18.7 +/- 0.7 cm/s for the strongest radial modes (l=0) and 25.2 +/- 0.9 cm/s for l=1. In addition, we use simulations to establish an equation that estimates the uncertainty of amplitude measurements that are made of other stars, given that the mode lifetime is known. Finally, we also give amplitudes of solar-like oscillations for three stars that we measured from a series of short observations with HARPS (gamma Ser, beta Aql and alpha For), together with revised amplitudes for five other stars for which we have previously published results (alpha Cen A, alpha Cen B, beta Hyi, nu Ind and delta Pav).Comment: 8 pages, accepted by ApJ. Minor wording changes and added a referenc

Environmental transmission of a personality trait: foster parent exploration behaviour predicts offspring exploration behaviour in zebra finches

Consistent behavioural differences among individuals are common in many species and can have important effects on offspring fitness. To understand such ‘personality’ variation, it is important to determine the mode ofinheritance, but this has been quantified for only a few species. Here, we report results from a breeding experiment in captive zebra finches, Taeniopygia guttata, in which we cross-fostered offspring to disentangle the importance of genetic and nongenetic transmission of behaviour. Genetic and foster-parents’ exploratory type was measured in a novel environment pre-breeding and offspring exploratory type was assessed at adulthood. Offspring exploratory type was predicted by the exploratory behaviour of the foster but not the genetic parents, whereas offspring sizewas predicted by genetic but not foster-parents’ size. Other aspects of the social environment, such as rearing regime (uni- versus biparental), hatching position, brood size or an individual’s sex did not influence offspring exploration. Our results therefore indicate that non-genetic transmission of behaviour can play an important role in shaping animal personality variation