Unusual light spectra from a two-level atom in squeezed vacuum

We investigate the interaction of an atom with a multi-channel squeezed vacuum. It turns out that the light coming out in a particular channel can have anomalous spectral properties, among them asymmetry of the spectrum, absence of the central peak as well as central hole burning for particular parameters. As an example plane-wave squeezing is considered. In this case the above phenomena can occur for the light spectra in certain directions. In the total spectrum these phenomena are washed out.Comment: 16 pages, LaTeX, 3 figures (included via epsf

Probing GABAA receptors with inhibitory neurosteroids

γ-aminobutyric acid type A receptors (GABAARs) are important components of the central nervous system and they are functionally tasked with controlling neuronal excitability. These receptors are subject to post-translational modification and also to modulation by endogenous regulators, such as the neurosteroids. These modulators can either potentiate or inhibit GABAAR function. Whilst the former class of neurosteroids are considered to bind to and act from the transmembrane domain of the receptor, the domains that are important for the inhibitory neurosteroids remain less clear. In this study, we systematically compare a panel of recombinant synaptic-type and extrasynaptic-type GABAARs expressed in heterologous cell systems for their sensitivity to inhibition by the classic inhibitory neurosteroid, pregnenolone sulphate. Generally, peak GABA current responses were inhibited less compared to steady-state currents, implicating the desensitised state in inhibition. Moreover, pregnenolone sulphate inhibition increased with GABA concentration, but showed minimal voltage dependence. There was no strong dependence of inhibition on receptor subunit composition, the exception being the ρ1 receptor, which is markedly less sensitive. By using competition experiments with pregnenolone sulphate and the GABA channel blocker picrotoxinin, discrete binding sites are proposed. Furthermore, by assessing inhibition using site-directed mutagenesis and receptor chimeras comprising α, β or γ subunits with ρ1 subunits, the receptor transmembrane domains are strongly implicated in mediating inhibition and most likely the binding location for pregnenolone sulphate in GABAARs

Spitzer Mid-Infrared Photometry of 500 - 750 K Brown Dwarfs

Mid-infrared data, including Spitzer warm-IRAC [3.6] and [4.5] photometry, is critical for understanding the cold population of brown dwarfs now being found, objects which have more in common with planets than stars. As effective temperature (T_eff) drops from 800 K to 400 K, the fraction of flux emitted beyond 3 microns increases rapidly, from about 40% to >75%. This rapid increase makes a color like H-[4.5] a very sensitive temperature indicator, and it can be combined with a gravity- and metallicity-sensitive color like H-K to constrain all three of these fundamental properties, which in turn gives us mass and age for these slowly cooling objects. Determination of mid-infrared color trends also allows better exploitation of the WISE mission by the community. We use new Spitzer Cycle 6 IRAC photometry, together with published data, to present trends of color with type for L0 to T10 dwarfs. We also use the atmospheric and evolutionary models of Saumon & Marley to investigate the masses and ages of 13 very late-type T dwarfs, which have H-[4.5] > 3.2 and T_eff ~ 500 K to 750 K.Comment: To be published in the on-line version of the Proceedings of Cool Stars 16 (ASP Conference Series). This is an updated version of Leggett et al. 2010 ApJ 710 1627; a photometry compilation is available at http://www.gemini.edu/staff/slegget

‘RE/TRS’ is a Girl’s Subject: Talking about Gender and the Discourse of ‘Religion’ in UK Educational Spaces

This article addresses what appears to be a retrenchment into narrower forms of identification and an increased suspicion of difference in the context of educational policy in the UK – especially in relation to ‘Religious Education’. The adoption of standardized management protocols – ‘managerialism’ – across most if not all policy contexts including public educational spaces reduces spaces for encountering or addressing genuine difference and for discovering something new and different. A theory of the ‘feminization of religion’ associated historically with Barbara Welter, provides some useful insights as to why this might be, suggesting that those in British society who would prefer to see greater separation from ‘religion’ in ‘secular’ schools may well also be caught up in forms of gender stereotyping

Where do we go from here? An assessment of navigation performance using a compass versus a GPS unit

The Global Positioning System (GPS) looks set to replace the traditional map and compass for navigation tasks in military and civil domains. However, we may ask whether GPS has a real performance advantage over traditional methods. We present an exploratory study using a waypoint plotting task to compare the standard magnetic compass against a military GPS unit, for both expert and non-expert navigators. Whilst performance times were generally longer in setting up the GPS unit, once navigation was underway the GPS was more efficient than the compass. For mediumto long-term missions, this means that GPS could offer significant performance benefits, although the compass remains superior for shorter missions. Notwithstanding the performance times, significantly more errors, and more serious errors, occurred when using the compass. Overall, then, the GPS offers some clear advantages, especially for non-expert users. Nonetheless, concerns over the development of cognitive maps remain when using GPS technologies

Operationalising a metric of nitrogen impacts on biodiversity for the UK response to a data request from the Coordination Centre for Effects

As a signatory party to the Convention on Long Range Transboundary Air Pollution (CLRTAP), the UK has been requested to provide biodiversity metrics for use in assessing impacts of atmospheric nitrogen (N) pollution. Models of soil and vegetation responses to N pollution can predict changes in habitat suitability for many plant and lichen species. Metrics are required to relate changes in a set of species to biodiversity targets. In a previous study, the suitability of the habitat for a set of positive indicator-species was found to be the measure, out of potential outputs from models currently applicable to the UK, which was most clearly related to the assessment methods of habitat specialists at the Statutory Nature Conservation Bodies (SNCBs). This report describes the calculation of values for a metric, based on this principle, for a set of example habitats under different N pollution scenarios. The examples are mainly from Natura-2000 sites, and are defined at EUNIS Level 3 (e.g. F4.1 Wet heath). Values for the biodiversity metric were shown to be greater on all sites in the “Background” scenario than in the scenario with greater N and S pollution, illustrating a positive response of biodiversity to reduced pollution. Results of the study were submitted in response to the ‘Call for Data 2012-14’ by the CLTRAP Co-ordination Centre for Effects (CCE), and presented at the 24th CCE Workshop in April 2014. Metrics calculated on a similar basis were also presented by the Netherlands, Switzerland and Denmark. Such metrics indicate biodiversity status more accurately than other types of metric such as Simpson index or similarity to a reference community, so it was decided to adopt habitat-suitability for positive indicator-species as a common basis for a biodiversity metric in this context. Further work is needed to determine the typical range of metric values in different habitats, and threshold values for damage and recovery. Requirements are likely to be specified in detail in the next CCE Call for Data. The current study shows that a biodiversity metric based on habitat-suitability for positive indicator-species is a useful and responsive method for summarising outputs of models of air pollution impacts on ecosystems

Open Science and Open Innovation in Socio-Political Context: Knowledge Production and Societal Impact in an Age of Populism

This conceptual paper traces the origins and progress of Open Science and proposes its generative coupling to Open Innovation in the contemporary socio-political context; where universities are re-imaging their civic missions in the face of anti-establishment populist politics. This setting is one of changing knowledge production regimes and institutional pressures that create contradictions identifiable through the prism of the series of scientific norms conceptualised by Robert K. Merton. This paper privileges a sociological perspective to proffer scientific knowledge production as a societally embedded process, which is well illustrated by scholarship in the Science and Technology Studies (STS) and Science in Society fields. In doing so, it identifies the co-evolution, co-existence and co-production of Open Science with Open Innovation; and notes how it shares the attributes of other recent diagnoses of changing knowledge production regimes; in particular Mode 2, post-normal science and the Quadruple Helix. It also argues that Open Science can be coupled with Open Innovation to catalyse positive societal change, but that the rise of a populist post-truth era opposed to objectivity, expertise and technocratic political solutions gives the demand for openness and participation a different complexion. Merton’s norms provide a useful lens to observe recent shifts in the delivery of science, knowledge and innovation in society towards more inclusive, ethical and sustainable outcomes; and expose the limited reflection on how the appropriation and exploitation of open scientific knowledge encounters industrial R&D and Open Innovation

Approaching the Ground State of Frustrated A-site Spinels: A Combined Magnetization and Polarized Neutron Scattering Study

We re-investigate the magnetically frustrated, {\it diamond-lattice-antiferromagnet} spinels FeAl$_2$O$_4$ and MnAl$_2$O$_4$ using magnetization measurements and diffuse scattering of polarized neutrons. In FeAl$_2$O$_4$, macroscopic measurements evidence a "cusp" in zero field-cooled susceptibility around 13~K. Dynamic magnetic susceptibility and {\it memory effect} experiments provide results that do not conform with a canonical spin-glass scenario in this material. Through polarized neutron scattering studies, absence of long-range magnetic order down to 4~K is confirmed in FeAl$_2$O$_4$. By modeling the powder averaged differential magnetic neutron scattering cross-section, we estimate that the spin-spin correlations in this compound extend up to the third nearest-neighbour shell. The estimated value of the Land\'{e} $g$ factor points towards orbital contributions from Fe$^{2+}$. This is also supported by a Curie-Weiss analysis of the magnetic susceptibility. MnAl$_2$O$_4$, on the contrary, undergoes a magnetic phase transition into a long-range ordered state below $\approx$ 40~K, which is confirmed by macroscopic measurements and polarized neutron diffraction. However, the polarized neutron studies reveal the existence of prominent spin-fluctuations co-existing with long-range antiferromagnetic order. The magnetic diffuse intensity suggests a similar short range order as in FeAl$_2$O$_4$. Results of the present work supports the importance of spin-spin correlations in understanding magnetic response of frustrated magnets like $A$-site spinels which have predominant short-range spin correlations reminiscent of the "spin liquid" state.Comment: 10 pages, 10 figures, double-column, accepted in Phys. Rev. B, 201