Milliarcsecond Structures of Variable Peaked-Spectrum Sources

Spectral variability offers a new technique to identify small scale structures from scintillation, as well as determining the absorption mechanism for peaked-spectrum (PS) radio sources. In this paper, we present very long baseline interferometry (VLBI) imaging using the Long Baseline Array (LBA) of two PS sources, MRC0225-065 and PMNJ0322-4820, identified as spectrally variable from observations with the Murchison Widefield Array (MWA). We compare expected milliarcsecond structures based on the detected spectral variability with direct LBA imaging. We find MRC0225-065 is resolved into three components, a bright core and two fainter lobes, roughly 430pc projected separation. A comprehensive analysis of the magnetic field, host galaxy properties, and spectral analysis implies that MRC0225-065 is a young radio source with recent jet activity over the last 10^2-10^3years. We find PMNJ0322-4820 is unresolved on milliarcsecond scales. We conclude PMNJ0322-4820 is a blazar with flaring activity detected in 2014 with the MWA. We use spectral variability to predict morphology and find these predictions consistent with the structures revealed by our LBA images.Comment: Accepted for publication in PASA. 11 pages, 4 figure

On the breaking of collinear factorization in QCD

We investigate the breakdown of collinear factorization for non-inclusive observables in hadron-hadron collisions. For pure QCD processes, factorization is violated at the three-loop level and it has a structure identical to that encountered previously in the case of super-leading logarithms. In particular, it is driven by the non-commutation of Coulomb/Glauber gluon exchanges with other soft exchanges. Beyond QCD, factorization may be violated at the two-loop level provided that the hard subprocess contains matrix element contributions with phase differences between different colour topologies.Comment: Version 2: minor improvements for journal publicatio

A rare presentation of the Klinefelter's syndrome

A 16 years old boy with Chronic Renal Failure (CRF) was not suspected of having Klinefelter's syndrome until he complained of painful gynecomastia. He was under haemodialysis for 2 years. At first, he was in an approximately full pubertal development (P5, G5), but he had a small and a firm testis (length 2.2cm) and some degree of facial male pattern hair. He also had a decreased upper to lower body segment ratio and despite having chronic renal failure, he was taller than his parents and siblings. His laboratory tests showed high levels of FSH and normal levels of LH and testosterone. With regards to all these findings, we suspected that there might be an occult Klinefelter's syndrome. So, we made his karyotype that showed a 47XXY pattern. Because there are only a few number of cases that have occult Klinefelter's syndrome in the basis of chronic renal failure, we decided to report this case

Galaxy protocluster candidates around z ~ 2.4 radio galaxies

We study the environments of 6 radio galaxies at 2.2 < z < 2.6 using wide-field near-infrared images. We use colour cuts to identify galaxies in this redshift range, and find that three of the radio galaxies are surrounded by significant surface overdensities of such galaxies. The excess galaxies that comprise these overdensities are strongly clustered, suggesting they are physically associated. The colour distribution of the galaxies responsible for the overdensity are consistent with those of galaxies that lie within a narrow redshift range at z ~ 2.4. Thus the excess galaxies are consistent with being companions of the radio galaxies. The overdensities have estimated masses in excess of 10^14 solar masses, and are dense enough to collapse into virizalised structures by the present day: these structures may evolve into groups or clusters of galaxies. A flux-limited sample of protocluster galaxies with K < 20.6 mag is derived by statistically subtracting the fore- and background galaxies. The colour distribution of the protocluster galaxies is bimodal, consisting of a dominant blue sequence, comprising 77 +/- 10% of the galaxies, and a poorly populated red sequence. The blue protocluster galaxies have similar colours to local star-forming irregular galaxies (U -V ~ 0.6), suggesting most protocluster galaxies are still forming stars at the observed epoch. The blue colours and lack of a dominant protocluster red sequence implies that these cluster galaxies form the bulk of their stars at z < 3.Comment: Accepted for publication in MNRA

CO line emission in the halo of a radio galaxy at z=2.6

We report the detection of luminous CO(3-2) line emission in the halo of the z=2.6 radio galaxy (HzRG) TXS0828+193, which has no detected counterpart at optical to mid-infrared wavelengths implying a stellar mass < few x10^9 M_sun and relatively low star-formation rates. With the IRAM PdBI we find two CO emission line components at the same position at ~80 kpc distance from the HzRG along the axis of the radio jet, with different blueshifts of few 100 km s^-1 relative to the HzRG and a total luminosity of ~2x10^10 K km s^-1 pc^2 detected at 8 sigma significance. HzRGs have significant galaxy overdensities and extended halos of metal-enriched gas often with embedded clouds or filaments of denser material, and likely trace very massive dark-matter halos. The CO emission may be associated with a gas-rich, low-mass satellite galaxy with little on-going star formation, in contrast to all previous CO detections of galaxies at similar redshifts. Alternatively, the CO may be related to a gas cloud or filament and perhaps jet-induced gas cooling in the outer halo, somewhat in analogy with extended CO emission found in low-redshift galaxy clusters.Comment: MNRAS Letters, accepte

Floral temperature and optimal foraging: is heat a feasible floral reward for pollinators?

As well as nutritional rewards, some plants also reward ectothermic pollinators with warmth. Bumble bees have some control over their temperature, but have been shown to forage at warmer flowers when given a choice, suggesting that there is some advantage to them of foraging at warm flowers (such as reducing the energy required to raise their body to flight temperature before leaving the flower). We describe a model that considers how a heat reward affects the foraging behaviour in a thermogenic central-place forager (such as a bumble bee). We show that although the pollinator should spend a longer time on individual flowers if they are warm, the increase in total visit time is likely to be small. The pollinator's net rate of energy gain will be increased by landing on warmer flowers. Therefore, if a plant provides a heat reward, it could reduce the amount of nectar it produces, whilst still providing its pollinator with the same net rate of gain. We suggest how heat rewards may link with plant life history strategies

On the Monadic Second-Order Transduction Hierarchy

We compare classes of finite relational structures via monadic second-order transductions. More precisely, we study the preorder where we set C \subseteq K if, and only if, there exists a transduction {\tau} such that C\subseteq{\tau}(K). If we only consider classes of incidence structures we can completely describe the resulting hierarchy. It is linear of order type {\omega}+3. Each level can be characterised in terms of a suitable variant of tree-width. Canonical representatives of the various levels are: the class of all trees of height n, for each n \in N, of all paths, of all trees, and of all grids

Searching for R-Parity Violation at Run-II of the Tevatron

We present an outlook for possible discovery of supersymmetry with broken R-parity at Run II of the Tevatron. We first present a review of the literature and an update of the experimental bounds. In turn we then discuss the following processes: 1. Resonant slepton production followed by R-parity violating decay, (a) via $LQD^c$ and (b) via $LLE^c$. 2. How to distinguish resonant slepton production from $Z'$ or $W'$ production. 3. Resonant slepton production followed by the decay to neutralino LSP, which decays via $LQD^c$. 4. Resonant stop production followed by the decay to a chargino, which cascades to the neutralino LSP. 5. Gluino pair production followed by the cascade decay to charm squarks which decay directly via $L_1Q_2D^c_1$. 6. Squark pair production followed by the cascade decay to the neutralino LSP which decays via $L_1Q_2D^c_1$. 7. MSSM pair production followed by the cascade decay to the LSP which decays (a) via $LLE^c$, (b) via $LQD^c$, and (c) via $U^cD^cD^c$, respectively. 8. Top quark and top squark decays in spontaneous R-parity violation.Comment: 39 pages, 51 figures, LaTex, reqires aipproc2.sty and axodraw.sty. To be published in the Physics at Run II Workshop: Supersymmetry/Higgs. Text has been edited by H. Dreiner. Author list on front page has been correcte

Jet vetoing and Herwig++

We investigate the simulation of events with gaps between jets with a veto on additional radiation in the gap in Herwig++. We discover that the currently-used random treatment of radiation in the parton shower is generating some unphysical behaviour for wide-angle gluon emission in QCD 2 to 2 scatterings. We explore this behaviour quantitatively by making the same assumptions as the parton shower in the analytical calculation. We then modify the parton shower algorithm in order to correct the simulation of QCD radiation.Comment: 18 pages, 11 figure