Was Dan Janzen (1977) right about aphid clones being a "super-organism", i.e. a single "evolutionary individual"? : new insights from the use of molecular marker systems

Dan Janzen proposed in a paper in 1977 (loc. cit.), that a clone of aphids and for that matter dandelions consists, respectively, of one large ‘super-organism’. In effect a single evolutionary individual able to exploit resources over an expanded geographical range, and sometimes with aphids also, a wider range of resources (different kinds of host plants), much more than if the organism concerned were a single individual. Such a view is of course based on the notion that an asexual lineage (clone) has strict genetic fidelity, that is to say, is genetically identical over its entire genome between clone mates. This seems a highly unlikely scenario and indeed, modern molecular markers have revealed a plethora of mutational events within such so-called clones. Here in this talk I provide evidence from aphids that they are not ‘perfect forms’ but rather show a range of variations, including evidence of hybridization events, and that they can and do adapt to environmental circumstances, sometimes swiftly. Hence that even as asexual lineages, aphids are able to exploit new ecological circumstances and flourish, e.g. host adapted forms, whilst some species, notably the highly polyphagous peach-potato aphid (Myzus persicae), have also evolved resistance to a range of pesticides, and by so doing, have managed to survive in the face of these poisons. However, there are fitness costs associated with such adaptation, more especially in the highly resistant aphids. Because of the variation and adaptation shown by particular aphid species and asexual lineages, they cannot be described as a single evolutionary unit in a ‘Janzenian’ sense. What they show is ecological plasticity and an ability to adapt quickly, in large part enhanced by their incredible rate of reproduction and population expansion. Some migrating winged aphids are constrained in their exploitation of new habitats by environmental factors – geographical, climatic and ecological, especially lack of suitable hosts. In contrast, some other aphid species have seemingly colonized large areas of the world (probably aided by human agency) so that deciding what a population is exactly is a difficult task. It may even be that certain ‘super clones’ detected using molecular markers have indeed spread far and wide, clones which appear to fit the description of being ‘general purpose genotypes’ in that they can feed on a range of plant hosts under a range of different geographical-climatic conditions. As such, they are nearest to Dan Janzen’s views, although here again, strict genetic fidelity is not necessarily proven, only accepted from the application of a limited number of markers, e.g. multilocus genotypes in the case of microsatellite markers

Was Dan Janzen (1977) right about aphid clones being a "super-organism", i.e. a single "evolutionary individual"? : new insights from the use of molecular marker systems

Dan Janzen proposed in a paper in 1977 (loc. cit.), that a clone of aphids and for that matter dandelions consists, respectively, of one large ‘super-organism’. In effect a single evolutionary individual able to exploit resources over an expanded geographical range, and sometimes with aphids also, a wider range of resources (different kinds of host plants), much more than if the organism concerned were a single individual. Such a view is of course based on the notion that an asexual lineage (clone) has strict genetic fidelity, that is to say, is genetically identical over its entire genome between clone mates. This seems a highly unlikely scenario and indeed, modern molecular markers have revealed a plethora of mutational events within such so-called clones. Here in this talk I provide evidence from aphids that they are not ‘perfect forms’ but rather show a range of variations, including evidence of hybridization events, and that they can and do adapt to environmental circumstances, sometimes swiftly. Hence that even as asexual lineages, aphids are able to exploit new ecological circumstances and flourish, e.g. host adapted forms, whilst some species, notably the highly polyphagous peach-potato aphid (Myzus persicae), have also evolved resistance to a range of pesticides, and by so doing, have managed to survive in the face of these poisons. However, there are fitness costs associated with such adaptation, more especially in the highly resistant aphids. Because of the variation and adaptation shown by particular aphid species and asexual lineages, they cannot be described as a single evolutionary unit in a ‘Janzenian’ sense. What they show is ecological plasticity and an ability to adapt quickly, in large part enhanced by their incredible rate of reproduction and population expansion. Some migrating winged aphids are constrained in their exploitation of new habitats by environmental factors – geographical, climatic and ecological, especially lack of suitable hosts. In contrast, some other aphid species have seemingly colonized large areas of the world (probably aided by human agency) so that deciding what a population is exactly is a difficult task. It may even be that certain ‘super clones’ detected using molecular markers have indeed spread far and wide, clones which appear to fit the description of being ‘general purpose genotypes’ in that they can feed on a range of plant hosts under a range of different geographical-climatic conditions. As such, they are nearest to Dan Janzen’s views, although here again, strict genetic fidelity is not necessarily proven, only accepted from the application of a limited number of markers, e.g. multilocus genotypes in the case of microsatellite markers

The Loss of Some Strength Characteristics of Coated Magazine Paper as a Result of Exposure to Elevated Temperatures

Introduction The purpose of this work is to investigate the effect that varying degrees of temperature have on the strength properties of coated magazine stock. Paper of this type encounters high temperature conditions primarily in the ink drying operations following the printing of the web. The strength with which the paper meets the cutting, folding and binding methods which follow the drying operation are of paramount importance to the printer. Throughout the work, attempts were made to assimilate conditions encountered in present day commercial practice

A quantum computer using a trapped-ion spin molecule and microwave radiation

We propose a new design for a quantum information processor where qubits are encoded into Hyperfine states of ions held in a linear array of individually tailored microtraps and sitting in a spatially varying magnetic field. The magnetic field gradient introduces spatially dependent qubit transition frequencies and a type of spin-spin interaction between qubits. Single and multi-qubit manipulation is achieved via resonant microwave pulses as in liquid-NMR quantum computation while the qubit readout and reset is achieved through trapped-ion fluorescence shelving techniques. By adjusting the microtrap configurations we can tailor, in hardware, the qubit resonance frequencies and coupling strengths. We show the system possesses a side-band transition structure which does not scale with the size of the processor allowing scalable frequency discrimination between qubits. By using large magnetic field gradients, one can readout and reset the qubits in the ion chain via frequency selective optical pulses avoiding the need for many tightly focused laser beams for spatial qubit addressing.Comment: 7 pages, 2 figures. New references added, additional material on quantum error correction and device tolerance

The Stellar Population of Stripped Cluster Spiral NGC 4522: A Local Analog to K+A Galaxies?

We present observations of the stripped Virgo Cluster spiral NGC 4522, a clear, nearby example of a galaxy currently undergoing ISM-ICM stripping. Utilizing SparsePak integral field spectroscopy on the WIYN 3.5m telescope and GALEX UV photometry, we present an analysis of the outer disk (r > 3 kpc) stellar population of this galaxy, beyond the HI and Halpha truncation radius. We find that the star formation in the gas-stripped outer disk ceased very recently, ~100 Myr ago, in agreement with previous claims that this galaxy is currently being stripped. At the time of this stripping, data and models suggest that the galaxy experienced a modest starburst. The stripping is occurring in a region of the cluster well outside the cluster core, likely because this galaxy is experiencing extreme conditions from a dynamic ICM due to an ongoing sub-cluster merger. The outer disk has a spectrum of a K+A galaxy, traditionally observed in high-redshift cluster galaxies. In the case of NGC 4522, a K+A spectrum is formed by simple stripping of the interstellar gas by the hot intracluster medium. These data show K+A spectra can be created by cluster processes and that these processes likely extend beyond the cluster core.Comment: 5 pages, 3 figures, accepted for publication in ApJ Letter

The University of Michigan Centimeter-Band All Stokes Blazar Monitoring Program: Single-Dish Polarimetry as a Probe of Parsec-Scale Magnetic Fields

The University of Michigan 26-m paraboloid was dedicated to obtaining linear polarization and total flux density observations of blazars from the mid-1960s until June 2012 providing an unprecedented record tracking centimeter-band variability over decades at 14.5, 8.0, and 4.8 GHz for both targeted objects and members of flux-limited samples. In the mid-1970s through the mid-1980s, and during the last decade of the program, observations were additionally obtained of circular polarization for a small sample of radio-bright (S>5Jy), active sources. Key program results include evidence supporting class-dependent differences in the magnetic field geometry of BL Lac and QSO jets, identification of linear polarization changes temporally associated with flux outbursts supporting a shock-in-jet scenario, and determination of the spectral evolution of the Stokes V amplitude and polarity for testing proposed models. Recent radiative transfer modeling during large flares supports a jet scenario with a kinetically-dominated, relativistic flow at parsec scales with embedded turbulent magnetic fields and dynamically-weak ordered components which may be helical; the circular polarization observations are consistent with linear-to-circular mode conversion within this turbulent jet environment.Comment: 8 pages, 4 figures, Proceedings of the conference "Polarised Emission from Astrophysical Jets", June 12-16, 2017, Ierapetra, Greece, eds. E. Angelakis, M. Boettcher, and J.-L. Gome

A Comparison of the United States and Canadian Banking Systems in the Twentieth Century: Stability vs. Efficiency?

This paper asks whether the vaunted comparative stability of the Canadian banking system has been purchased at the cost of creating an oligopoly. We assembled a data set that compares bank failures, lending rates, interest paid on deposits and related variables over the period 1920 to 1980. Our principal findings are that: (1) interest rates paid on deposits were generally higher in Canada; (2) interest income received on securities was generally slightly higher in Canada; (3) interest rates charged on loans were generally quite similar; (4) net rates of return to equity were generally higher in Canada than in the U.S..