Tracing the Warm Hot Intergalactic Medium in the local Universe

We present a simple method for tracing the spatial distribution and predicting the physical properties of the Warm-Hot Intergalactic Medium (WHIM), from the map of galaxy light in the local universe. Under the assumption that biasing is local and monotonic we map the ~ 2 Mpc/h smoothed density field of galaxy light into the mass density field from which we infer the spatial distribution of the WHIM in the local supercluster. Taking into account the scatter in the WHIM density-temperature and density-metallicity relation, extracted from the z=0 outputs of high-resolution and large box size hydro-dynamical cosmological simulations, we are able to quantify the probability of detecting WHIM signatures in the form of absorption features in the X-ray spectra, along arbitrary directions in the sky. To illustrate the usefulness of this semi-analytical method we focus on the WHIM properties in the Virgo Cluster region.Comment: 16 pages 11 Figures. Discussion clarified, alternative methods proposed. Results unchanged. MNRAS in pres

The RKKY interactions and the Mott Transition

A two-site cluster generalization of the Hubbard model in large dimensions is examined in order to study the role of short-range spin correlations near the metal-insulator transition (MIT). The model is mapped to a two-impurity Kondo-Anderson model in a self-consistently determined bath, making it possible to directly address the competition between the Kondo effect and RKKY interactions in a lattice context. Our results indicate that the RKKY interactions lead to qualitative modifications of the MIT scenario even in the absence of long range antiferromagnetic ordering.Comment: 10 pages, 10 figures; to appear in Phys. Rev. B (1999

Anomalous electronic susceptibility in Bi2Sr2CuO6+d and comparison with other overdoped cuprates

We report magnetic susceptibility performed on overdoped Bi2Sr2CuO6+d powders as a function of oxygen doping d and temperature T. The decrease of the spin susceptibility with increasing T is confirmed. At sufficient high temperature, the spin susceptibility Chi_s presents an unusual linear temperature dependence Chi_s ~ Chi_s0 -Chi_1 T. Moreover, a linear correlation between Chi_1 and Chi_s0 for increasing hole concentration is displayed. A temperature Tchi, independent of hole doping characterizes this scaling. Comparison with other cuprates of the literature(LSCO, Tl-2201 and Bi-2212), over the same overdoped range, shows similarities with above results. These non conventional metal features will be discussed in terms of a singular narrow-band structure.Comment: 16 pages, 4 figure

Renormalization-group study of Anderson and Kondo impurities in gapless Fermi systems

Thermodynamic properties are presented for four magnetic impurity models describing delocalized fermions scattering from a localized orbital at an energy-dependent rate $\Gamma(\epsilon)$ which vanishes precisely at the Fermi level, $\epsilon = 0$. Specifically, it is assumed that for small $|\epsilon|$, $\Gamma(\epsilon)\propto|\epsilon|^r$ with $r>0$. The cases $r=1$ and $r=2$ describe dilute magnetic impurities in unconventional superconductors, ``flux phases'' of the two-dimensional electron gas, and zero-gap semiconductors. For the nondegenerate Anderson model, the depression of the low-energy scattering rate suppresses mixed valence in favor of local-moment behavior, and leads to a marked reduction in the exchange coupling on entry to the local-moment regime, with a consequent narrowing of the range of parameters within which the impurity spin becomes Kondo-screened. The relationship between the Anderson model and the exactly screened Kondo model with power-law exchange is examined. The intermediate-coupling fixed point identified in the latter model by Withoff and Fradkin (WF) has clear signatures in the thermodynamic properties and in the local magnetic response of the impurity. The underscreened, impurity-spin-one Kondo model and the overscreened, two-channel Kondo model both exhibit a conditionally stable intermediate-coupling fixed point in addition to unstable fixed points of the WF type. In all four models, the presence or absence of particle-hole symmetry plays a crucial role.Comment: 44 two-column REVTex pages, 31 epsf-embedded EPS figures. MINOR formatting changes. To appear in Phys. Rev.

Gene expression polymorphism underpins evasion of host immunity in an asexual lineage of the Irish potato famine pathogen

BACKGROUND: Outbreaks caused by asexual lineages of fungal and oomycete pathogens are a continuing threat to crops, wild animals and natural ecosystems (Fisher MC, Henk DA, Briggs CJ, Brownstein JS, Madoff LC, McCraw SL, Gurr SJ, Nature 484:186-194, 2012; Kupferschmidt K, Science 337:636-638, 2012). However, the mechanisms underlying genome evolution and phenotypic plasticity in asexual eukaryotic microbes remain poorly understood (Seidl MF, Thomma BP, BioEssays 36:335-345, 2014). Ever since the 19th century Irish famine, the oomycete Phytophthora infestans has caused recurrent outbreaks on potato and tomato crops that have been primarily caused by the successive rise and migration of pandemic asexual lineages (Goodwin SB, Cohen BA, Fry WE, Proc Natl Acad Sci USA 91:11591-11595, 1994; Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10:e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Cooke DEL, Cano LM, Raffaele S, Bain RA, Cooke LR, Etherington GJ, Deahl KL, Farrer RA, Gilroy EM, Goss EM, et al. PLoS Pathog 8:e1002940, 2012). However, the dynamics of genome evolution within these clonal lineages have not been determined. The objective of this study was to use a comparative genomics and transcriptomics approach to determine the molecular mechanisms that underpin phenotypic variation within a clonal lineage of P. infestans. RESULTS: Here, we reveal patterns of genomic and gene expression variation within a P. infestans asexual lineage by comparing strains belonging to the South American EC-1 clone that has dominated Andean populations since the 1990s (Yoshida K, Burbano HA, Krause J, Thines M, Weigel D, Kamoun S, PLoS Pathog 10e1004028, 2014; Yoshida K, Schuenemann VJ, Cano LM, Pais M, Mishra B, Sharma R, Lanz C, Martin FN, Kamoun S, Krause J, et al. eLife 2:e00731, 2013; Delgado RA, Monteros-Altamirano AR, Li Y, Visser RGF, van der Lee TAJ, Vosman B, Plant Pathol 62:1081-1088, 2013; Forbes GA, Escobar XC, Ayala CC, Revelo J, Ordonez ME, Fry BA, Doucett K, Fry WE, Phytopathology 87:375-380, 1997; Oyarzun PJ, Pozo A, Ordonez ME, Doucett K, Forbes GA, Phytopathology 88:265-271, 1998). We detected numerous examples of structural variation, nucleotide polymorphisms and loss of heterozygosity within the EC-1 clone. Remarkably, 17 genes are not expressed in one of the two EC-1 isolates despite apparent absence of sequence polymorphisms. Among these, silencing of an effector gene was associated with evasion of disease resistance conferred by a potato immune receptor. CONCLUSIONS: Our findings highlight the molecular changes underpinning the exceptional genetic and phenotypic plasticity associated with host adaptation in a pandemic clonal lineage of a eukaryotic plant pathogen. We observed that the asexual P. infestans lineage EC-1 can exhibit phenotypic plasticity in the absence of apparent genetic mutations resulting in virulence on a potato carrying the Rpi-vnt1.1 gene. Such variant alleles may be epialleles that arose through epigenetic changes in the underlying genes

Observation of an extended VHE gamma-ray emission from MSH 15-52 with CANGAROO-III

We have observed the supernova remnant MSH 15-52 (G320.4-1.2), which contains the gamma-ray pulsar PSR B1509-58, using the CANGAROO-III imaging atmospheric Cherenkov telescope array from April to June in 2006. We detected gamma rays above 810 GeV at the 7 sigma level during a total effective exposure of 48.4 hours. We obtained a differential gamma-ray flux at 2.35 TeV of (7.9+/-1.5_{stat}+/-1.7_{sys}) \times 10^{-13} cm^{-2}s^{-1}TeV^{-1} with a photon index of 2.21+/-0.39_{stat}+/-0.40_{sys}, which is compatible with that of the H.E.S.S. observation in 2004. The morphology shows extended emission compared to our Point Spread Function. We consider the plausible origin of the high energy emission based on a multi-wavelength spectral analysis and energetics arguments.Comment: 9 pages, 9 figures, Accepted in Ap

Observation of B0->pi0pi0

We report the first observation of the decay B0->pi0pi0, using a 253/fb data sample collected at the Upsilon(4S) resonance with the Belle detector at the KEKB e+e- collider. The measured branching fraction is BF(B0->pi0pi0) = {2.32 +0.4-0.5(stat) +0.2-0.3(syst)} x 10^-6, with a significance of 5.8 standard deviations including systematic uncertainties. We also make the first measurement of the direct CP violating asymmetry in this mode.Comment: 6 pages, 2 figures, submitted to ICHEP04, Beijing and Physical Review Letters. v2: a possible pile-up background is checked and a systematic error for it is include

Gravitational Waves From Known Pulsars: Results From The Initial Detector Era

We present the results of searches for gravitational waves from a large selection of pulsars using data from the most recent science runs (S6, VSR2 and VSR4) of the initial generation of interferometric gravitational wave detectors LIGO (Laser Interferometric Gravitational-wave Observatory) and Virgo. We do not see evidence for gravitational wave emission from any of the targeted sources but produce upper limits on the emission amplitude. We highlight the results from seven young pulsars with large spin-down luminosities. We reach within a factor of five of the canonical spin-down limit for all seven of these, whilst for the Crab and Vela pulsars we further surpass their spin-down limits. We present new or updated limits for 172 other pulsars (including both young and millisecond pulsars). Now that the detectors are undergoing major upgrades, and, for completeness, we bring together all of the most up-to-date results from all pulsars searched for during the operations of the first-generation LIGO, Virgo and GEO600 detectors. This gives a total of 195 pulsars including the most recent results described in this paper.United States National Science FoundationScience and Technology Facilities Council of the United KingdomMax-Planck-SocietyState of Niedersachsen/GermanyAustralian Research CouncilInternational Science Linkages program of the Commonwealth of AustraliaCouncil of Scientific and Industrial Research of IndiaIstituto Nazionale di Fisica Nucleare of ItalySpanish Ministerio de Economia y CompetitividadConselleria d'Economia Hisenda i Innovacio of the Govern de les Illes BalearsNetherlands Organisation for Scientific ResearchPolish Ministry of Science and Higher EducationFOCUS Programme of Foundation for Polish ScienceRoyal SocietyScottish Funding CouncilScottish Universities Physics AllianceNational Aeronautics and Space AdministrationOTKA of HungaryLyon Institute of Origins (LIO)National Research Foundation of KoreaIndustry CanadaProvince of Ontario through the Ministry of Economic Development and InnovationNational Science and Engineering Research Council CanadaCarnegie TrustLeverhulme TrustDavid and Lucile Packard FoundationResearch CorporationAlfred P. Sloan FoundationAstronom

Swift follow-up observations of candidate gravitational-wave transient events

We present the first multi-wavelength follow-up observations of two candidate gravitational-wave (GW) transient events recorded by LIGO and Virgo in their 2009-2010 science run. The events were selected with low latency by the network of GW detectors and their candidate sky locations were observed by the Swift observatory. Image transient detection was used to analyze the collected electromagnetic data, which were found to be consistent with background. Off-line analysis of the GW data alone has also established that the selected GW events show no evidence of an astrophysical origin; one of them is consistent with background and the other one was a test, part of a "blind injection challenge". With this work we demonstrate the feasibility of rapid follow-ups of GW transients and establish the sensitivity improvement joint electromagnetic and GW observations could bring. This is a first step toward an electromagnetic follow-up program in the regime of routine detections with the advanced GW instruments expected within this decade. In that regime multi-wavelength observations will play a significant role in completing the astrophysical identification of GW sources. We present the methods and results from this first combined analysis and discuss its implications in terms of sensitivity for the present and future instruments.Comment: Submitted for publication 2012 May 25, accepted 2012 October 25, published 2012 November 21, in ApJS, 203, 28 ( http://stacks.iop.org/0067-0049/203/28 ); 14 pages, 3 figures, 6 tables; LIGO-P1100038; Science summary at http://www.ligo.org/science/Publication-S6LVSwift/index.php ; Public access area to figures, tables at https://dcc.ligo.org/cgi-bin/DocDB/ShowDocument?docid=p110003

Search for gravitational waves associated with the InterPlanetary Network short gamma ray bursts

We outline the scientific motivation behind a search for gravitational waves associated with short gamma ray bursts detected by the InterPlanetary Network (IPN) during LIGO's fifth science run and Virgo's first science run. The IPN localisation of short gamma ray bursts is limited to extended error boxes of different shapes and sizes and a search on these error boxes poses a series of challenges for data analysis. We will discuss these challenges and outline the methods to optimise the search over these error boxes.Comment: Methods paper; Proceedings for Eduardo Amaldi 9 Conference on Gravitational Waves, July 2011, Cardiff, U