Dualisation of the D=7 Heterotic String

The dualisation and the first-order formulation of the D=7 abelian Yang-Mills supergravity which is the low energy effective limit of the D=7 fully Higssed heterotic string is discussed. The non-linear coset formulation of the scalars is enlarged to include the entire bosonic sector by introducing dual fields and by constructing the Lie superalgebra which generates the dualized coset element.Comment: 20 page

Dualisation of the D=9 Matter Coupled Supergravity

We perform the bosonic dualisation of the matter coupled N=1, D=9 supergravity. We derive the Lie superalgebra which parameterizes the coset map whose Cartan form realizes the second-order bosonic field equations. Following the non-linear coset construction we present the first-order formulation of the bosonic field equations as a twisted self-duality condition.Comment: 16 page

Duality Symmetries and G^{+++} Theories

We show that the non-linear realisations of all the very extended algebras G^{+++}, except the B and C series which we do not consider, contain fields corresponding to all possible duality symmetries of the on-shell degrees of freedom of these theories. This result also holds for G_2^{+++} and we argue that the non-linear realisation of this algebra accounts precisely for the form fields present in the corresponding supersymmetric theory. We also find a simple necessary condition for the roots to belong to a G^{+++} algebra.Comment: 35 pages. v2: 2 appendices added, other minor corrections. v3: tables corrected, other minor changes, one appendix added, refs. added. Version published in Class. Quant. Gra

Random Surfaces that Suppress Single Scattering

We present a method for generating numerically a one-dimensional random surface, defined by the equation x_3 = \zx, that suppresses single-scattering processes in the scattering of light from it within a specified range of scattering angles. Rigorous numerical calculations of the scattering of light from surfaces generated by this approach show that the single-scattering contribution to the mean scattered intensity is indeed suppressed within that range of angles.Comment: 3 pagers (Latex), 3 figure

Pain and delirium: mechanisms, assessment, and management

Purpose: Pain and delirium are common problems for older people. Both conditions are prevalent in acute hospital settings. In people living in the community, delirium often precipitates presentation to the emergency department. Pain and delirium are known to interact in a complex and multidirectional way. This can make it challenging for staff to recognize and treat pain in people with delirium. Methods: This paper aims to explore the complex relationship between pain and delirium and on pain assessment in delirium, drawing together evidence from a range of settings including acute medical, cardiac and orthopaedic post-operative cohorts, as well as from aged care. Results: A limited number of studies suggest there is an association between pain and delirium; however, this is a complex, particularly where analgesics which may-themselves cause delirium are prescribed. Factors acting on the pathway between pain and delirium may include depression, sleep deprivation and disturbance of the cholinergic system. Delirium affects the ability to self-report pain. The fluctuating nature of delirium as well as reduced awareness and attention may challenge practitioners in recognizing, assessing and treating pain. Evidence concerning the reliability and validity of current observational and self-assessment tools in people with delirium is unclear but some show promise in this population. Conclusion: The current evidence base regarding assessing pain in people with delirium is lacking. Tentative recommendations, drawing on current guidelines require robust testing. Guidelines for people with pain and dementia require adaptations regarding the unique characteristics of delirium. The complex interplay between dementia, pain and delirium warrants further investigation across a range of settings

Fermi surface of the colossal magnetoresistance perovskite La_{0.7}Sr_{0.3}MnO_{3}

Materials that exhibit colossal magnetoresistance (CMR) are currently the focus of an intense research effort, driven by the technological applications that their sensitivity lends them to. Using the angular correlation of photons from electron-positron annihilation, we present a first glimpse of the Fermi surface of a material that exhibits CMR, supported by ``virtual crystal'' electronic structure calculations. The Fermi surface is shown to be sufficiently cubic in nature that it is likely to support nesting.Comment: 5 pages, 5 PS figure

Symmetries in M-theory: Monsters, Inc

We will review the algebras which have been conjectured as symmetries in M-theory. The Borcherds algebras, which are the most general Lie algebras under control, seem natural candidates.Comment: 6 pages, talk given by PHL at Cargese 200

Expressed sequence tags from the oomycete fish pathogen Saprolegnia parasitica reveal putative virulence factors

Peer reviewedPublisher PD

Chromospheric Variability in SDSS M Dwarfs. II. Short-Timescale H-alpha Variability

[Abridged] We present the first comprehensive study of short-timescale chromospheric H-alpha variability in M dwarfs using the individual 15 min spectroscopic exposures for 52,392 objects from the Sloan Digital Sky Survey. Our sample contains about 10^3-10^4 objects per spectral type bin in the range M0-M9, with a total of about 206,000 spectra and a typical number of 3 exposures per object (ranging up to a maximum of 30 exposures). Using this extensive data set we find that about 16% of the sources exhibit H-alpha emission in at least one exposure, and of those about 45% exhibit H-alpha emission in all of the available exposures. Within the sample of objects with H-alpha emission, only 26% are consistent with non-variable emission, independent of spectral type. The H-alpha variability, quantified in terms of the ratio of maximum to minimum H-alpha equivalent width (R_EW), and the ratio of the standard deviation to the mean (sigma_EW/), exhibits a rapid rise from M0 to M5, followed by a plateau and a possible decline in M9 objects. In particular, R_EW increases from a median value of about 1.8 for M0-M3 to about 2.5 for M7-M9, and variability with R_EW>10 is only observed in objects later than M5. For the combined sample we find that the R_EW values follow an exponential distribution with N(R_EW) exp[-(R_EW-1)/2]; for M5-M9 objects the characteristic scale is R_EW-1\approx 2.7, indicative of stronger variability. In addition, we find that objects with persistent H-alpha emission exhibit smaller values of R_EW than those with intermittent H-alpha emission. Based on these results we conclude that H-alpha variability in M dwarfs on timescales of 15 min to 1 hr increases with later spectral type, and that the variability is larger for intermittent sources.Comment: Submitted to ApJ; 20 pages, 15 figure

Evolutionary theory and the ultimate-proximate distinction in the human behavioral sciences

To properly understand behavior, we must obtain both ultimate and proximate explanations. Put briefly, ultimate explanations are concerned with why a behavior exists, and proximate explanations are concerned with how it works. These two types of explanation are complementary and the distinction is critical to evolutionary explanation. We are concerned that they have become conflated in some areas of the evolutionary literature on human behavior. This article brings attention to these issues. We focus on three specific areas: the evolution of cooperation, transmitted culture, and epigenetics. We do this to avoid confusion and wasted effort—dangers that are particularly acute in interdisciplinary research. Throughout this article, we suggest ways in which misunderstanding may be avoided in the future