Comments on non-Abelian T-duals and their holographic description

We present three different Type IIB AdS4 Supergravity solutions, derived using the electrostatic-likeproblem formalism which preserves 8 Poincaré Supercharges. Two of these solutions correspond to the Abelian and non-Abelian T-duals of a Type IIA background, obtained from the dimensional reduction of 11D AdS4 × S7 Supergravity. The third solution is a new background with some special properties. We compute the Page charges in each case, and provide brane set-up descriptions of the geometries. Also, we argue that the non-Abelian T-dual can be understood as a zoom-in of a more general background with a well defined holographic dual

Compactification of 6d N=(1,0){\cal N}=(1,0) quivers, 4d SCFTs and their holographic dual Massive IIA backgrounds

In this paper we study an infinite family of Massive Type IIA backgrounds that holographically describe the twisted compactification of ${\cal N}=(1,0)$ six-dimensional SCFTs to four dimensions. The analysis of the branes involved suggests a four dimensional linear quiver QFT, that deconstructs the theory in six dimensions. For the case in which the system reaches a strongly coupled fixed point, we calculate some observables that we compare with holographic results. Two quantities measuring the number of degrees of freedom for the flow across dimensions are studied.Comment: 20 pages plus detailed appendices. References added, some typos corrected. Some clarifications. Version to be publishe

CW EPR investigation of red-emitting CaS:Eu phosphors: rationalization of local electronic structure

A series of commercial and prepared CaS:Eu2+ rare earth activated phosphors are investigated following different post‐synthetic treatments. A number of species directly related to the function of the material are characterized using electron paramagnetic resonance (EPR) spectroscopy. Isolated Eu2+ sites are identified and associated with the substitutional doping for Ca2+ in the lattice which are responsible for the 645 nm emission of interest. Another inactive Eu2+ site based within a “EuO” type phase aggregated on the surface of the material is also identified, as well as competitive F+ center defects that are known to reduce emission from the Eu2+ sites. Intrinsic Mn2+ impurities are identified and used as local order probes to determine changes in ordering and symmetry upon cryo‐milling and heating treatments of the samples. X‐ray photoelectron (XPS) and photoluminescence (PL) spectroscopies are also conducted to complement the local structure observations. The reported data is useful in understanding how the nature of the lattice affects ground state electronic structure of functional defective sites, for the development of efficient and selective materials

Searching down the fisheries information web : an initial reflection

Paper presented at the 8th International Grey Literature Conference, December 4-5, 2006 New Orleans, USA.The complex web of information ranges from pure science to applied techniques to management policies. All are important, yet have varying levels of accessibility and authority. Often the apex of the peer-reviewed journal article is considered the most important level discouraging scientists and managers, especially those in developing countries, from populating the other layers of the web that may be considered grey. We are particularly interested in how information produced in developing countries fits into this information web. To do so, we focused on one topic, mangroves, using it as a means to exemplify the complexity of the web of information and reveal publication patterns. Using search tools, we identified 2000-2005 mangrove-related publications regarding Africa and India, analyzed them by author’s location and affiliation, publication format and availability. Our preliminary analysis suggests that grey literature remains difficult to discover, the peer-reviewed journal is the most popular means of scientific communication, and open archives are just starting to have an impact on scholarly communication. The web of information would be strengthened by improving the discovery of the grey literature through greater visibility and accessibility.Publishing Research Quarterly - Vol. 23 no. 1Keywords: Developing countries, Scientific and technical literature, Grey literature, Scholarly publishin

Genome Sequence of E. coli O104:H4 Leads to Rapid Development of a Targeted Antimicrobial Agent against This Emerging Pathogen

A recent widespread outbreak of Escherichia coli O104:H4 in Germany demonstrates the dynamic nature of emerging and re-emerging food-borne pathogens, particularly STECs and related pathogenic E. coli. Rapid genome sequencing and public availability of these data from the German outbreak strain allowed us to identify an O-antigen-specific bacteriophage tail spike protein encoded in the genome. We synthesized this gene and fused it to the tail fiber gene of an R-type pyocin, a phage tail-like bacteriocin, and expressed the novel bacteriocin such that the tail fiber fusion was incorporated into the bacteriocin structure. The resulting particles have bactericidal activity specifically against E. coli strains that produce the O104 lipopolysaccharide antigen, including the outbreak strain. This O-antigen tailspike-R-type pyocin strategy provides a platform to respond rapidly to emerging pathogens upon the availability of the pathogen's genome sequence

A survey for variable young stars with small telescopes: II - mapping a protoplanetary disc with stable structures at 0.15 au

The HOYS citizen science project conducts long term, multifilter, high cadence monitoring of large YSO samples with a wide variety of professional and amateur telescopes. We present the analysis of the light curve of V1490 Cyg in the Pelican Nebula. We show that colour terms in the diverse photometric data can be calibrated out to achieve a median photometric accuracy of 0.02 mag in broadband filters, allowing detailed investigations into a variety of variability amplitudes over timescales from hours to several years. Using Gaia DR2 we estimate the distance to the Pelican Nebula to be 870 +70 −55 pc. V1490 Cyg is a quasi-periodic dipper with a period of 31.447 ± 0.011 d. The obscuring dust has homogeneous properties, and grains larger than those typical in the ISM. Larger variability on short timescales is observed in U and Rc−Hα, with U-amplitudes reaching 3 mag on timescales of hours, indicating the source is accreting. The Hα equivalent width and NIR/MIR colours place V1490 Cyg between CTTS/WTTS and transition disk objects. The material responsible for the dipping is located in a warped inner disk, about 0.15 AU from the star. This mass reservoir can be filled and emptied on time scales shorter than the period at a rate of up to 10−10 M�/yr, consistent with low levels of accretion in other T Tauri stars. Most likely the warp at this separation from the star is induced by a protoplanet in the inner accretion disk. However, we cannot fully rule out the possibility of an AA Tau-like warp, or occultations by the Hill sphere around a forming planet

A survey for variable young stars with small telescopes: VI — Analysis of the outbursting Be stars NSW284, Gaia19eyy, and VES263

This paper is one in a series reporting results from small telescope observations of variable young stars. Here, we study the repeating outbursts of three likely Be stars based on long-term optical, near-infrared, and mid-infrared photometry for all three objects, along with follow-up spectra for two of the three. The sources are characterised as rare, truly regularly outbursting Be stars. We interpret the photometric data within a framework for modelling light curve morphology, and find that the models correctly predict the burst shapes, including their larger amplitudes and later peaks towards longer wavelengths. We are thus able to infer the start and end times of mass loading into the circumstellar disks of these stars. The disk sizes are typically 3 – 6 times the areas of the central star. The disk temperatures are ∼ 40 %, and the disk luminosities are ∼ 10 % of those of the central Be star, respectively. The available spectroscopy is consistent with inside-out evolution of the disk. Higher excitation lines have larger velocity widths in their double-horned shaped emission profiles. Our observations and analysis support the decretion disk model for outbursting Be stars