Anti-self-dual conformal structures with null Killing vectors from projective structures

Using twistor methods, we explicitly construct all local forms of four--dimensional real analytic neutral signature anti--self--dual conformal structures $(M,[g])$ with a null conformal Killing vector. We show that $M$ is foliated by anti-self-dual null surfaces, and the two-dimensional leaf space inherits a natural projective structure. The twistor space of this projective structure is the quotient of the twistor space of $(M,[g])$ by the group action induced by the conformal Killing vector. We obtain a local classification which branches according to whether or not the conformal Killing vector is hyper-surface orthogonal in $(M, [g])$. We give examples of conformal classes which contain Ricci--flat metrics on compact complex surfaces and discuss other conformal classes with no Ricci--flat metrics.Comment: 43 pages, 4 figures. Theorem 2 has been improved: ASD metrics are given in terms of general projective structures without needing to choose special representatives of the projective connection. More examples (primary Kodaira surface, neutral Fefferman structure) have been included. Algebraic type of the Weyl tensor has been clarified. Final version, to appear in Commun Math Phy

Patient Perceptions of Effectiveness in Treatments for Menière's Disease: a National Survey in Italy

Objective: The aim of this study was to investigate current treatment practices and self-reported effectiveness in Menière's disease. Materials and Methods: Members of two Italian Menière's disease support (n=170) with ≥6-month history of Menière's disease were administered an online survey about recent treatments. Vertigo episode count, work absenteeism, and limitations in family life, social life,work or travel, as included in the Social Life and Work Impact of Dizziness (SWID) Questionnaire before and after recent treatments were queried. Results: Twenty-four different treatments were reported for Menière's disease, with dietary modifications (55%), diuretics (47%), and betahistine (41%) being most common. The majority (71%) received multiple simultaneous treatments. Prior to the most recent treatments 78-89% of respondents indicated limitations in family or social life, work or traveling. After their most recent treatment, respondents reported improvements in mean vertigo episode counts (5.7±7.6 vs. 2.6 ±4.6, p<0.001), days off work per month (10.1 ±9.2 vs. 4.2 ±6.7, p<0.001), and proportions indicating limitations in any functional measure assessed (p<0.05). These findings were consistent regardless of treatment approach (all p<0.05). Intratympanic gentamicin provided the greatest reductions in vertigo count, functional limitations, and work absenteeism (all p<0.01) as well as the fewest respondents reporting post-treatment functional limitations (16-37%). Conclusions: Despite numerous treatment approaches targeting different proposed pathophysiology for Menière's disease in this cross-sectional survey, all treatments are reported as effective by patients. These findings support a prominent placebo effect in Menière's disease and highlight challenges in studying treatment outcomes; there is a critical need to better understand Menière's disease

Developing Tautai Lavea‘i, a Breast Cancer Patient Nativation Program in American Samoa

This article focuses on development of the psychosocial-cultural components of a breast cancer patient navigation program (PNP) in the medically underserved, albeit culturally-rich Territory of American Samoa. Efforts to reduce cancer morbidity and mortality in American Samoa must necessarily consider the territory’s limited cancer resources and indigenous culture, as well as the individuals at risk for poor health outcomes and premature death. Within this complex set of challenges resides the prospect of health equity and opportunities for advancing service innovations that meaningfully plait native ways of knowing with Western evidencebased practice. Increasing adherence to diagnostic and treatment procedures is of significant concern to the American Samoa Cancer Community Network who initiated this inquiry to assess patients lost to follow-up, describe treatment-seeking influences, and identify cultural preferences for inclusion in a PNP tailored on fa‘aSamoa or the Samoan worldview

Noncommutative Electromagnetism As A Large N Gauge Theory

We map noncommutative (NC) U(1) gauge theory on R^d_C X R^{2n}_{NC} to U(N -> \infty) Yang-Mills theory on R^d_C, where R^d_C is a d-dimensional commutative spacetime while R^{2n}_{NC} is a 2n-dimensional NC space. The resulting U(N) Yang-Mills theory on R^d_C is equivalent to that obtained by the dimensional reduction of (d+2n)-dimensional U(N) Yang-Mills theory onto R^d_C. We show that the gauge-Higgs system (A_\mu,\Phi^a) in the U(N -> \infty) Yang-Mills theory on R^d_C leads to an emergent geometry in the (d+2n)-dimensional spacetime whose metric was determined by Ward a long time ago. In particular, the 10-dimensional gravity for d=4 and n=3 corresponds to the emergent geometry arising from the 4-dimensional N=4 vector multiplet in the AdS/CFT duality. We further elucidate the emergent gravity by showing that the gauge-Higgs system (A_\mu,\Phi^a) in half-BPS configurations describes self-dual Einstein gravity.Comment: 25 pages; More clarifications, to appear in Eur. Phys. J.

The JCMT Legacy Survey of the Gould Belt: a first look at Orion B with HARP

‘The definitive version is available at www3.interscience.wiley.com '. Copyright Royal Astronomical Society.The Gould Belt Legacy Survey will survey nearby star-forming regions (within 500 pc), using Heterodyne Array Receiver Programme (HARP), Submillimetre Common-User Bolometer Array 2 and Polarimeter 2 on the James Clerk Maxwell Telescope. This paper describes the initial data obtained using HARP to observe 12CO, 13CO and C18O J= 3 → 2 towards two regions in Orion B, NGC 2024 and NGC 2071. We describe the physical characteristics of the two clouds, calculating temperatures and opacities utilizing all the three isotopologues. We find good agreement between temperatures calculated from CO and from dust emission in the dense, energetic regions. We determine the mass and energetics of the clouds, and of the high-velocity material seen in 12CO emission, and compare the relative energetics of the high- and low-velocity material in the two clouds. We present a clumpfind analysis of the 13CO condensations. The slope of the condensation mass functions, at the high-mass ends, is similar to the slope of the initial mass function.Peer reviewe

Application of Pulsed Field Gel Electrophoresis to Determine γ-ray-induced Double-strand Breaks in Yeast Chromosomal Molecules

The frequency of DNA double-strand breaks (dsb) was determined in yeast cells exposed to γ-rays under anoxic conditions. Genomic DNA of treated cells was separated by pulsed field gel electrophoresis, and two different approaches for the evaluation of the gels were employed: (1) The DNA mass distribution profile obtained by electrophoresis was compared to computed profiles, and the number of DSB per unit length was then derived in terms of a fitting procedure; (2) hybridization of selected chromosomes was performed, and a comparison of the hybridization signals in treated and untreated samples was then used to derive the frequency of dsb

Electrically Charged Topological Solitons

Two new families of T-Dual integrable models of dyonic type are constructed. They represent specific $A_n^{(1)}$ singular Non-Abelian Affine Toda models having U(1) global symmetry. Their 1-soliton spectrum contains both neutral and U(1) charged topological solitons sharing the main properties of 4-dimensional Yang-Mills-Higgs monopoles and dyons. The semiclassical quantization of these solutions as well as the exact counterterms and the coupling constant renormalization are studied.Comment: 40 pages, latex, typos corrected in eq. (2.3), new section on spin of solitons added, extended discussion on T-duality relation between axial and vector topological theta terms in new subsection 2.

Tomato: a crop species amenable to improvement by cellular and molecular methods

Tomato is a crop plant with a relatively small DNA content per haploid genome and a well developed genetics. Plant regeneration from explants and protoplasts is feasable which led to the development of efficient transformation procedures. In view of the current data, the isolation of useful mutants at the cellular level probably will be of limited value in the genetic improvement of tomato. Protoplast fusion may lead to novel combinations of organelle and nuclear DNA (cybrids), whereas this technique also provides a means of introducing genetic information from alien species into tomato. Important developments have come from molecular approaches. Following the construction of an RFLP map, these RFLP markers can be used in tomato to tag quantitative traits bred in from related species. Both RFLP's and transposons are in the process of being used to clone desired genes for which no gene products are known. Cloned genes can be introduced and potentially improve specific properties of tomato especially those controlled by single genes. Recent results suggest that, in principle, phenotypic mutants can be created for cloned and characterized genes and will prove their value in further improving the cultivated tomato.

Measurement of the scintillation time spectra and pulse-shape discrimination of low-energy beta and nuclear recoils in liquid argon with DEAP-1

The DEAP-1 low-background liquid argon detector was used to measure scintillation pulse shapes of electron and nuclear recoil events and to demonstrate the feasibility of pulse-shape discrimination (PSD) down to an electron-equivalent energy of 20 keV. In the surface dataset using a triple-coincidence tag we found the fraction of beta events that are misidentified as nuclear recoils to be $<1.4\times 10^{-7}$ (90% C.L.) for energies between 43-86 keVee and for a nuclear recoil acceptance of at least 90%, with 4% systematic uncertainty on the absolute energy scale. The discrimination measurement on surface was limited by nuclear recoils induced by cosmic-ray generated neutrons. This was improved by moving the detector to the SNOLAB underground laboratory, where the reduced background rate allowed the same measurement with only a double-coincidence tag. The combined data set contains $1.23\times10^8$ events. One of those, in the underground data set, is in the nuclear-recoil region of interest. Taking into account the expected background of 0.48 events coming from random pileup, the resulting upper limit on the electronic recoil contamination is $<2.7\times10^{-8}$ (90% C.L.) between 44-89 keVee and for a nuclear recoil acceptance of at least 90%, with 6% systematic uncertainty on the absolute energy scale. We developed a general mathematical framework to describe PSD parameter distributions and used it to build an analytical model of the distributions observed in DEAP-1. Using this model, we project a misidentification fraction of approx. $10^{-10}$ for an electron-equivalent energy threshold of 15 keV for a detector with 8 PE/keVee light yield. This reduction enables a search for spin-independent scattering of WIMPs from 1000 kg of liquid argon with a WIMP-nucleon cross-section sensitivity of $10^{-46}$ cm$^2$, assuming negligible contribution from nuclear recoil backgrounds.Comment: Accepted for publication in Astroparticle Physic

Reducible connections and non-local symmetries of the self-dual Yang-Mills equations

We construct the most general reducible connection that satisfies the self-dual Yang-Mills equations on a simply connected, open subset of flat $\mathbb{R}^4$. We show how all such connections lie in the orbit of the flat connection on $\mathbb{R}^4$ under the action of non-local symmetries of the self-dual Yang-Mills equations. Such connections fit naturally inside a larger class of solutions to the self-dual Yang-Mills equations that are analogous to harmonic maps of finite type.Comment: AMSLatex, 15 pages, no figures. Corrected in line with the referee's comments. In particular, restriction to simply-connected open sets now explicitly stated. Version to appear in Communications in Mathematical Physic