NS Fivebrane and Tachyon Condensation

We argue that a semi-infinite D6-brane ending on an NS5-brane can be obtained from the condensation of the tachyon on the unstable D9-brane of type IIA theory. The construction uses a combination of the descriptions of these branes as solitons of the worldvolume theory of the D9-brane. The NS5-brane, in particular, involves a gauge bundle which is operator valued, and hence is better thought of as a gerbe.Comment: 20 pages, harvma

Maximal violation of Bell inequalities by position measurements

We show that it is possible to find maximal violations of the CHSH-Bell inequality using only position measurements on a pair of entangled non-relativistic free particles. The device settings required in the CHSH inequality are done by choosing one of two times at which position is measured. For different assignments of the "+" outcome to positions, namely to an interval, to a half line, or to a periodic set, we determine violations of the inequalities, and states where they are attained. These results have consequences for the hidden variable theories of Bohm and Nelson, in which the two-time correlations between distant particle trajectories have a joint distribution, and hence cannot violate any Bell inequality.Comment: 13 pages, 4 figure

Strong Shift Equivalence of C∗C^*-correspondences

We define a notion of strong shift equivalence for $C^*$-correspondences and show that strong shift equivalent $C^*$-correspondences have strongly Morita equivalent Cuntz-Pimsner algebras. Our analysis extends the fact that strong shift equivalent square matrices with non-negative integer entries give stably isomorphic Cuntz-Krieger algebras.Comment: 26 pages. Final version to appear in Israel Journal of Mathematic

Morpholino Oligonucleotide Cross-Linked Hydrogels as Portable Optical Oligonucleotide Biosensors

© 2018 American Chemical Society. Morpholino Oligonucleotides (MOs), an uncharged DNA analogue, are functionalized with an acrylamide moiety and incorporated into polymer hydrogels as responsive cross-links for microRNA sequence detection. The MO cross-links can be selectively cleaved by a short target analyte single-stranded DNA (ssDNA) sequence based on microRNA, inducing a distinct swelling response measured optically. The MO cross-links offer significant improvement over DNA based systems through improved thermal stability, no salt requirement and 1000-fold improved sensitivity over a comparative biosensor, facilitating a wider range of sensing conditions. Analysis was also achieved using a mobile phone camera, demonstrating portability

Using molecular rotors to probe gelation

A series of fluorescent probes, including a number of molecular rotors, have been used to follow the self-assembly of dipeptide-based low molecular weight gelators. We show that these probes can be used to gain an insight into the assembly process. Thioflavin T, a commonly used stain for β-sheets, appears to act as a molecular rotor in these gelling systems, with the fluorescence data closely matching that of other rotors. The molecular rotor was incorporated into an assay system with glucose oxidase to enable glucose-concentration specific gelation and hence generating a fluorescent output. Applying this system to urine from patients with various levels of glycosuria (a symptom of diabetes), it was found to provide excellent correlation with different clinical assessments of diabetes. This demonstrates a new concept in gelation-linked biosensing for a real clinical problem

The effect of solvent choice on the gelation and final hydrogel properties of Fmoc–diphenylalanine

Gels can be formed by dissolving Fmoc–diphenylalanine (Fmoc–PhePhe or FmocFF) in an organic solvent and adding water. We show here that the choice and amount of organic solvent allows the rheological properties of the gel to be tuned. The differences in properties arise from the microstructure of the fibre network formed. The organic solvent can then be removed post-gelation, without significant changes in the rheological properties. Gels formed using acetone are meta-stable and crystals of FmocFF suitable for X-ray diffraction can be collected from this gel

Homology and K--Theory Methods for Classes of Branes Wrapping Nontrivial Cycles

We apply some methods of homology and K-theory to special classes of branes wrapping homologically nontrivial cycles. We treat the classification of four-geometries in terms of compact stabilizers (by analogy with Thurston's classification of three-geometries) and derive the K-amenability of Lie groups associated with locally symmetric spaces listed in this case. More complicated examples of T-duality and topology change from fluxes are also considered. We analyse D-branes and fluxes in type II string theory on ${\mathbb C}P^3\times \Sigma_g \times {\mathbb T}^2$ with torsion $H-$flux and demonstrate in details the conjectured T-duality to ${\mathbb R}P^7\times X^3$ with no flux. In the simple case of $X^3 = {\mathbb T}^3$, T-dualizing the circles reduces to duality between ${\mathbb C}P^3\times {\mathbb T}^2 \times {\mathbb T}^2$ with $H-$flux and ${\mathbb R}P^7\times {\mathbb T}^3$ with no flux.Comment: 27 pages, tex file, no figure

“That's cool, you’re a musician and you drink”: Exploring entertainers’ accounts of their unique workplace relationship with alcohol

This qualitative research investigates the alcohol experiences of entertainers who perform within licensed premises. Previous, mainly quantitative, studies have found that entertainers, specifically musicians, are an occupational group who drink excessively. This qualitative study draws on a wider sample of entertainers to examine their accounts of drinking in the workplace and the explanations they provide for this. We conducted individual semi-structured interviews (n = 24) with band-members, variety acts and DJs in Glasgow, Scotland. This revealed a workplace characterised by continual opportunities for often free alcohol consumption. Unlike most occupations, for entertainers ‘drinking-on-the-job’ was normative, expected, and sometimes encouraged by peers, the public, employers or sponsors. Entertainers also experienced performance-related incentives to drink before, during and/or after a show; including anxiety, matching their intoxication level to the audience's, and ‘reward-drinking’. This qualitative research confirms the unique nature of the entertainer-alcohol link, even in comparison to that found within other leisure industry occupations. While providing some explanation as to why entertainers might drink excessively, participants’ accounts also suggested potential strategies for avoiding the negative outcomes of workplace drinking

Wavelets and graph C∗C^*-algebras

Here we give an overview on the connection between wavelet theory and representation theory for graph $C^{\ast}$-algebras, including the higher-rank graph $C^*$-algebras of A. Kumjian and D. Pask. Many authors have studied different aspects of this connection over the last 20 years, and we begin this paper with a survey of the known results. We then discuss several new ways to generalize these results and obtain wavelets associated to representations of higher-rank graphs. In \cite{FGKP}, we introduced the "cubical wavelets" associated to a higher-rank graph. Here, we generalize this construction to build wavelets of arbitrary shapes. We also present a different but related construction of wavelets associated to a higher-rank graph, which we anticipate will have applications to traffic analysis on networks. Finally, we generalize the spectral graph wavelets of \cite{hammond} to higher-rank graphs, giving a third family of wavelets associated to higher-rank graphs

Linking micellar structures to hydrogelation for salt-triggered dipeptide gelators

Some functionalised dipeptides can form hydrogels when salts are added to solutions at high pH. We have used surface tension, conductivity, rheology, optical, confocal and scanning electron microscopy, 1H NMR and UV-Vis spectroscopy measurements to characterise fully the phase behaviour of solutions of one specific gelator, 2NapFF, at 25 °C at pH 10.5. We show that this specific naphthalene–dipeptide undergoes structural transformations as the concentration is increased, initially forming spherical micelles, then worm-like micelles, followed by association of these worm-like micelles. On addition of a calcium salt, gels are generally formed as long as worm-like micelles are initially present in solution, although there are structural re-organisations that occur at lower concentrations, allowing gelation at lower than expected concentration. Using IR and SANS, we show the differences between the structures present in the solution and hydrogel phases