title: Evolution of the axial magnetic field in solar filament channels

authors: Litvinenko, Yuri E.

subjects: magnetic reconnection

abstract: Formation of solar filament channels by photospheric magnetic reconnection is considered. A magnetohydrodynamic model for magnetic merging, driven by converging convective motions in the photosphere, is presented. Evolution of the axial magnetic field in a channel is analyzed. An exact time-dependent analytical solution for the field profile in a steady stagnation-point flow is derived. The maximum magnetic field in the channel is determined, and its dependence on the reconnection inflow speed is discussed. The quantitative results show that the maximum axial magnetic field in a forming channel is an indicator of the photospheric reconnection rate, in agreement with recent solar observations and laboratory experiments.

text: Evolution of the axial magnetic field in solar filament channels Formation of solar filament channels by photospheric magnetic reconnection is considered. A magnetohydrodynamic model for magnetic merging, driven by converging convective motions in the photosphere, is presented. Evolution of the axial magnetic field in a channel is analyzed. An exact time-dependent analytical solution for the field profile in a steady stagnation-point flow is derived. The maximum magnetic field in the channel is determined, and its dependence on the reconnection inflow speed is discussed. The quantitative results show that the maximum axial magnetic field in a forming channel is an indicator of the photospheric reconnection rate, in agreement with recent solar observations and laboratory experiments.

year: 2010

title: Identification and structure elucidation of epoxyjanthitrems from Lolium perenne infected with the endophytic fungus Epichloë festucae var. lolii and determination of the tremorgenic and anti-insect activity of epoxyjanthitrem I.

authors: Finch, Sarah C.

subjects: AR37

abstract: Epoxyjanthitrems I-IV (1-4) and epoxyjanthitriol (5) were isolated from seed of perennial ryegrass (Lolium perenne) infected with the endophytic fungus Epichloë festucae var. lolii. Although structures for epoxyjanthitrems I-IV have previously been proposed in the literature, this is the first report of a full structural elucidation yielding NMR (Nuclear magnetic resonance) assignments for all five epoxyjanthitrem compounds, and additionally, it is the first isolation of epoxyjanthitriol (5). Epoxyjanthitrem I induced tremors in mice and gave a dose dependent reduction in weight gain and feeding for porina (Wiseana cervinata), a common pasture pest in New Zealand. These data suggest that epoxyjanthitrems are involved in the observed effects of the AR37 endophyte on livestock and insect pests.

text: Identification and structure elucidation of epoxyjanthitrems from Lolium perenne infected with the endophytic fungus Epichloë festucae var. lolii and determination of the tremorgenic and anti-insect activity of epoxyjanthitrem I. Epoxyjanthitrems I-IV (1-4) and epoxyjanthitriol (5) were isolated from seed of perennial ryegrass (Lolium perenne) infected with the endophytic fungus Epichloë festucae var. lolii. Although structures for epoxyjanthitrems I-IV have previously been proposed in the literature, this is the first report of a full structural elucidation yielding NMR (Nuclear magnetic resonance) assignments for all five epoxyjanthitrem compounds, and additionally, it is the first isolation of epoxyjanthitriol (5). Epoxyjanthitrem I induced tremors in mice and gave a dose dependent reduction in weight gain and feeding for porina (Wiseana cervinata), a common pasture pest in New Zealand. These data suggest that epoxyjanthitrems are involved in the observed effects of the AR37 endophyte on livestock and insect pests.

year: 2020-08-17

title: What’s in a name? The sense of reference, the rigidity of designators and the history of causes when determining the names of the two main islands of Aotearoa/New Zealand

authors: Parker, Martin

subjects: New Zealand

abstract: The New Zealand Geographic Board recently revealed that the two main islands of Aotearoa/New Zealand have never been officially named. The revelation made both national and international news and led to a large number of publicly aired comments on the matter, suggesting that something so fundamental and seemingly innocuous as naming is in fact likely to generate a good deal of controversy, no more so than in a bicultural/bilingual context. This paper will examine the phenomenon of naming from a number of angles. After discussing a layperson’s idea of what is meant by the meaning of names, we shall attempt to apply a number of theoretical models from the field of Language Philosophy to the case of the main islands of Aotearoa/New Zealand: the Descriptivist approach of Frege and Russell, Kripke’s Rigid Designators, and Causal Grounding theory. We shall conclude that, in the case of applying the first two of these, there is a question mark over whether any of the current names for the two islands, both Māori and Pākehā, are in fact names at all; in terms of applying the theory of Causal Grounding, we are drawn to the conclusion that in history lies the key to the future.

text: What’s in a name? The sense of reference, the rigidity of designators and the history of causes when determining the names of the two main islands of Aotearoa/New Zealand The New Zealand Geographic Board recently revealed that the two main islands of Aotearoa/New Zealand have never been officially named. The revelation made both national and international news and led to a large number of publicly aired comments on the matter, suggesting that something so fundamental and seemingly innocuous as naming is in fact likely to generate a good deal of controversy, no more so than in a bicultural/bilingual context. This paper will examine the phenomenon of naming from a number of angles. After discussing a layperson’s idea of what is meant by the meaning of names, we shall attempt to apply a number of theoretical models from the field of Language Philosophy to the case of the main islands of Aotearoa/New Zealand: the Descriptivist approach of Frege and Russell, Kripke’s Rigid Designators, and Causal Grounding theory. We shall conclude that, in the case of applying the first two of these, there is a question mark over whether any of the current names for the two islands, both Māori and Pākehā, are in fact names at all; in terms of applying the theory of Causal Grounding, we are drawn to the conclusion that in history lies the key to the future.

year: 2010-02