D-Brane Dynamics and NS5 Rings

We consider the classical motion of a probe D-brane moving in the background geometry of a ring of NS5 branes, assuming that the latter are non-dynamical. We analyse the solutions to the Dirac-Born-Infield (DBI) action governing the approximate dynamics of the system. In the near horizon (throat) approximation we find several exact solutions for the probe brane motion. These are compared to numerical solutions obtained in more general cases. One solution of particular interest is when the probe undergoes oscillatory motion through the centre of the ring (and perpendicular to it). By taking the ring radius sufficiently large, this solution should remain stable to any stringy corrections coming from open-strings stretching between the probe and the NS5-branes along the ring.Comment: 17 pages, Latex, 8 figures; References adde

Geometrical Tachyon Kinks and NS5 Branes

We further investigate the $NS$5 ring background using the tachyon map. Mapping the radion fields to the rolling tachyon helps to explain the motion of a probe $Dp$-brane in this background. It turns out that the radion field becomes tachyonic when the brane is confined to one dimensional motion inside the ring. We find explicit solutions for the geometrical tachyon field that describe stable kink solutions which are similar to those of the open string tachyon. Interestingly in the case of the geometric tachyon, the dynamics is controlled by a cosine potential. In addition, we couple a constant electric field to the probe-brane, but find that the only stable kink solutions occur when there is zero electric field or a critical field value. We also investigate the behaviour of Non-BPS branes in this background, and find that the end state of any probe brane is that of tachyonic matter 'trapped' around the interior of the ring. We conclude by considering compactification of the ring solution in one of the transverse directions.Comment: Latex, 24 pages, 1 eps fig; clarifying comments added to Section 2; typos correcte

Results of a nine month home-based physical activity intervention for people living with HIV.

Background: The purpose of this investigation was to test the feasibility of a home-based moderate-intensity physical activity (MPA) program for people living with HIV/AIDS (PLWHA) currently taking antiretroviral therapy (ART). Methods: 68 participants recruited for a 9-month home-based PA intervention aimed to reduce risk factors of cardiovascular disease for PLWHA taking ART. All participants received an educational weight loss workbook and a pedometer for self-monitoring of physical activity. The intervention group received elastic Therabands® for strength training in addition to telephone based behavioral coaching. Clinical assessments were conducted at baseline and each follow-up which also included psychometric questionnaires and PA levels via the SenseWear® armband accelerometer. Results: Of the 57 completing the study, 29 of those were in the intervention group and 28 were in the standard care group. Results show that the home-based PA intervention was not successful in increasing the total amount of MPA for PLWHA. However there was a trend (p=0.08) of decreasing sedentary time. In a secondary analysis those who increased PA by \u3e10% observed decreases in waist circumference and improved functioning at 18 weeks. None of the changes observed were significant after controlling for all potential confounders. Conclusions: A home-based exercise approach with telephone-based coaching may not be a feasible method for increasing MPA among PLWHA. Slight decreases in sedentary time indicate some positive changes in activity habits. A possible strategy to improve studies similar to this is to incorporate a group based social interaction each week similar to that of a support group

Fuzzy Sphere Dynamics and Non-Abelian DBI in Curved Backgrounds

We consider the non-Abelian action for the dynamics of $N Dp'$-branes in the background of $M Dp$-branes, which parameterises a fuzzy sphere using the SU(2) algebra. We find that the curved background leads to collapsing solutions for the fuzzy sphere except when we have $D0$ branes in the $D6$ background, which is a realisation of the gravitational Myers effect. Furthermore we find the equations of motion in the Abelian and non-Abelian theories are identical in the large $N$ limit. By picking a specific ansatz we find that we can incorporate angular momentum into the action, although this imposes restriction upon the dimensionality of the background solutions. We also consider the case of non-Abelian non-BPS branes, and examine the resultant dynamics using world-volume symmetry transformations. We find that the fuzzy sphere always collapses but the solutions are sensitive to the combination of the two conserved charges and we can find expanding solutions with turning points. We go on to consider the coincident $NS$5-brane background, and again construct the non-Abelian theory for both BPS and non-BPS branes. In the latter case we must use symmetry arguments to find additional conserved charges on the world-volumes to solve the equations of motion. We find that in the Non-BPS case there is a turning solution for specific regions of the tachyon and radion fields. Finally we investigate the more general dynamics of fuzzy $\mathbb{S}^{2k}$ in the $Dp$-brane background, and find collapsing solutions in all cases.Comment: 49 pages, 3 figures, Latex; Version to appear in JHE

DBI Inflation in the Tip Region of a Warped Throat

Previous work on DBI inflation, which achieves inflation through the motion of a $D3$ brane as it moves through a warped throat compactification, has focused on the region far from the tip of the throat. Since reheating and other observable effects typically occur near the tip, a more detailed study of this region is required. To investigate these effects we consider a generalized warp throat where the warp factor becomes nearly constant near the tip. We find that it is possible to obtain 60 or more e-folds in the constant region, however large non-gaussianities are typically produced due to the small sound speed of fluctuations. For a particular well-studied throat, the Klebanov-Strassler solution, we find that inflation near the tip may be generic and it is difficult to satisfy current bounds on non-gaussianity, but other throat solutions may evade these difficulties.Comment: 26 pages, 1 figure. v1. references added, typos corrected v2. clarifications mad

A cGAS-dependent response links DNA damage and senescence in alveolar epithelial cells:A potential drug target in IPF

Alveolar epithelial cell (AEC) senescence is implicated in the pathogenesis of idiopathic pulmonary fibrosis (IPF). Mitochondrial dysfunction including release of mitochondrial DNA (mtDNA) is a feature of senescence, which led us to investigate the role of the DNA-sensing GMP-AMP synthase (cGAS) in IPF, with a focus on AEC senescence. cGAS expression in fibrotic tissue from lungs of IPF patients was detected within cells immunoreactive for epithelial cell adhesion molecule (EpCAM) and p21, epithelial and senescence markers respectively. Submerged primary cultures of AECs isolated from lung tissue of IPF patients (IPF-AECs, n=5) exhibited higher baseline senescence than AECs from control donors (Ctrl-AECs, n=5-7), as assessed by increased nuclear histone 2AXγ phosphorylation, p21 mRNA and expression of senescence-associated secretory phenotype (SASP) cytokines. Pharmacological cGAS inhibition using RU.521 diminished IPF-AEC senescence in culture and attenuated induction of Ctrl-AEC senescence following etoposide-induced DNA damage. Short interfering RNA (siRNA) knockdown of cGAS also attenuated etoposide-induced senescence of the AEC line, A549. Higher levels of mtDNA were detected in the cytosol and culture supernatants of primary IPF- and etoposide-treated Ctrl-AECs when compared to Ctrl-AECs at baseline. Furthermore, ectopic mtDNA augmented cGAS-dependent senescence of Ctrl-AECs, whereas DNAse I treatment diminished IPF-AEC senescence. This study provides evidence that a self-DNA driven, cGAS-dependent response augments AEC senescence, identifying cGAS as a potential therapeutic target for IPF

Semiclassical relations and IR effects in de Sitter and slow-roll space-times

We calculate IR divergent graviton one-loop corrections to scalar correlators in de Sitter space, and show that the leading IR contribution may be reproduced via simple semiclassical consistency relations. One can likewise use such semiclassical relations to calculate leading IR corrections to correlators in slow-roll inflation. The regulated corrections shift the tensor/scalar ratio and consistency relation of single field inflation, and non-gaussianity parameters averaged over very large distances. For inflation of sufficient duration, for example arising from a chaotic inflationary scenario, these corrections become of order unity. First-order corrections of this size indicate a breakdown of the perturbative expansion, and suggest the need for a non-perturbative description of the corresponding regime. This is analogous to a situation argued to arise in black hole evolution, and to interfere with a sharp perturbative calculation of "missing information" in Hawking radiation.Comment: 32 pages, 2 figures; v2: running of spectral index included and other minor changes; v3: minor changes to agree with published versio

High speed chalcogenide glass electrochemical metallization cells with various active metals

We fabricated electrochemical metallization (ECM) cells using a GaLaSO solid electrolyte, a InSnO inactive electrode and active electrodes consisting of various metals (Cu, Ag, Fe, Cu, Mo, Al). Devices with Ag and Cu active metals showed consistent and repeatable resistive switching behaviour, and had a retention of 3 and >43 days, respectively; both had switching speeds of < 5 ns. Devices with Cr and Fe active metals displayed incomplete or intermittent resistive switching, and devices with Mo and Al active electrodes displayed no resistive switching ability. Deeper penetration of the active metal into the GaLaSO layer resulted in greater resistive switching ability of the cell. The off-state resistivity was greater for more reactive active metals which may be due to a thicker intermediate layer

Crop Updates 2000 - Cereals part 2

This session covers twenty papers from different authors: DISEASE 1. Forecasting aphid and virus risk in cereals, Debbie Thackray, Jenny Hawkes and Roger Jones, Agriculture Western Australia and Centre for Legumes in Mediterranean Agriculture 2. Cereal Diagnostics, Dominie Wright, Agriculture Western Australia 3. The economic returns from spraying for leaf rust in the central wheatbelt in 1999, Peter Carlton, Trials Coordinator, Elders Limited 4. Impact and Management of Yellow Spot and Leaf Rust in the Northern Agricultural Region, Jat Bhathal and Robert Loughman, Agriculture Western Australia 5. Leaf disease management in wheat and barley in the southern agricultural region, K. Jayasena, R. Loughman and J. Majewski, Agriculture Western Australia 6. Root nematode update, R. Loughman1, S. Kelly1, G. Holloway2, N. Venn1 and D. Diepeveen1 1 Agriculture Western Australia, 2Agriculture Victoria WHEAT AGRONOMY 7. Small Grain Screenings in wheat - the agronomic issues, Brenda Shackley, Agriculture Western Australia, 8. Response of New Wheat Varieties to Seed Rate and applied Nitrogen in the North, Darshan Sharma and Wal Anderson, Agriculture Western Australia 9. Seen vigour in wheat, Darshan Sharma and Wal Anderson, Agriculture Western Australia 10. Influence of the Time of Sowing on New Wheat Varieties in the North, Darshan Sharma and Wal Anderson, Agriculture Western Australia 11, Wheat performance in a high disease season on the South Coast. 1. Disease and grain quality on the Esperance sandplain, Mohammad Amjad, Vanessa Dooley and Wal Anderson, Agriculture Western Australia 12. Wheat performance in a high disease season on the South Coast. 2. Leaf area, disease and yield at Gibson and Salmon Gums, Mohammad Amjad, Vanessa Dooley and Wal Anderson, Agriculture Western Australia 13. Agronomic Evaluation of Wheat in the Central Wheatbelt of Western Australia, Peter Burgess and Ashley Bacon, Agritech Crop Research 14. Mechanisms influencing grain susceptibility to black point in wheat, Frances Hoyle, University of Western Australia and Agriculture Western Australia 15. Improving paddock productivity using renovation cropping techniques on heavier soils, Frances Hoyle, Agriculture Western Australia 16. Improving paddock productivity using renovation cropping techniques on sandplain soils, Frances Hoyle and Keith Devenish, Agriculture Western Australia 17. Increasing profit - Is it possible using high input package approach for cereal production? M. Appelbee, IAMA Agri Services 18. Improving wheat yield, soil physical and chemical fertility by a package of deep ripping, gypsum and complete nutrients, M.A. Hamza and W.K. Anderson, Agriculture Western Australia 19. Organic Wheat - Production System Guidelines, Steven McCoy, Centre for New Industries Development 20. Durum wheat obtains a premium over bread wheat, Steven Penny, Agriculture Western Australi