Nitrogenase activity associated with codium species from New Zealand marine habitats

Nitrogenase activity, measured as acetylene reduction, was recorded at rates up to 1028 nmol.h \g * dry weight for Codium adhaerens (Cabr.) Ag. var. convolutum Dellow and Codium fragile (Sur.) Hariot subsp. tomentosoides (Van Goor) Silva collected from New Zealand habitats. In both species the ability to reduce acetylene is invariably associated with the presence of a heterocystous blue-green alga, Calothrix sp., epiphytic or embedded in the Codium thallus. A highly significant (P < 0.001) correlation between heterocyst frequency and nitrogenase activity was found. Nitrogenase and net photosynthesis of the Codium-Calothrix system have different steady-state responses to light intensity, and the kinetics of the two processes also differ in that nitrogenase is slow to respond to illumination or darkening. Glucose additions to Codium did not significantly increase nitrogenase activity. Nitrogenase is relatively insensitive to oxygen tension over the range 0-1.0 atm (0-1.033 kgf.cnT2) and still occurs at 1.5 atm (1.55 kgf.cm"2); this condition is unique in all nitrogenase systems thus far reported. Collectively these facts suggest that Calothrix is the agent primarily responsible for nitrogenase activity in these Codium species

Valuing Companion Animals: Alternatives to Market Value

This article explores how the lives of companion animals – pets by another name – are valued in negligence actions when they are wrongfully killed, and the justifications underlying the current approach of market value. Because Canadians welcome companion animals into their families for reasons that go beyond economics, this paper argues that a proposition of law that values them based only on market value fails accurately to identify and compensate for the loss suffered when a companion animal is wrongfully killed. Compensating a plaintiff for either mental distress or loss of companionship appears, initially, to be an attractive alternative to the market value approach; however, because of the cautious manner with which psychological injuries have been approached in Canada, and the common law position that loss of companionship is non-compensable, these alternatives are impracticable means by which the present legal position could be modified. While compensation for mental distress can respond to some situations involving the wrongful death of a pet, it cannot provide redress in all such actions. A solution to the challenges posed by the present legal position lies in valuation by reference to the investment made by animal guardians during the course of a companion animal’s lifetime. This method would allow for a companion animal’s value to be accurately measured, thereby permitting compensation that adequately reflects the entirety of the loss suffered. Legislative change, creating a statutory cause of action for the attendant non-pecuniary loss, would be the most effective way of achieving this proposed change

Shot noise in resonant tunneling through a zero-dimensional state with a complex energy spectrum

We investigate the noise properties of a GaAs/AlGaAs resonant tunneling structure at bias voltages where the current characteristic is determined by single electron tunneling. We discuss the suppression of the shot noise in the framework of a coupled two-state system. For large bias voltages we observed super-Poissonian shot noise up to values of the Fano factor $\alpha \approx 10$.Comment: 4 pages, 4 figures, accepted for Phys. Rev.

Myths of merit. Judicial diversity and the image of the superhero judge

This thesis is a critical analysis of reforms of the judicial appointments process which are designed to encourage judicial diversity. It does so by applying the concept of myth to law, and argues that because the judge is understood as a superhero, the definition of judicial merit has come to reflect this ideal, which is neither accurate nor sufficient. It neither reflects what judges do, nor adequately describes what it is that judges should do. Therefore it is argued that attempts to diversify the judiciary are limited by the image of the superhero judge, which, in this thesis, is described as myth, with distinct socio-cultural effects. It is argued that there are two potential methods of approaching judicial diversity. The first is diversity of form, which focuses on gender, ethnic background, different levels of physical ability and economic status of the individual. The second is diversity of thought, which focuses on achieving a judiciary diverse in terms of its experience of and approaches to the law. In order to argue that diversity of thought is preferable to diversity of form, this thesis discusses in depth the decision making processes of the most 'different' law lord, namely Baroness Hale, who, as the first female and the first academic law lord, represents both diversity of form and diversity of thought. This thesis argues that her difference is not a result of her gender, but a result of her different experiences with and approaches to the law. The argument put forward in this thesis is that in understanding the judge as superhero, identified in this thesis as the Herculean image of the judge, the role of the judiciary is limited. This thesis argues that the role of the judge has changed in the wake of the Human Rights Act 1998. The role of the judge has become more politicised, and as such it is necessary to revisit popular understandings of the judge. It is argued that the reforms to the judicial appointments process confirm the ideal of the superhero judge and reflect an expectation that the 'different’ judges, that is, judges from different backgrounds, will simply confirm to the superhero or Herculean ideal. This thesis then puts forward the image of Loki, the trickster god of Norse mythology, as a more attractive judicial image, arguing that the changes in the judicial role require an image of the judge which is more flexible and able to accommodate different experiences, understandings and approaches to the law

Re-entrant resonant tunneling

We study the effect of electron-electron interactions on the resonant-tunneling spectroscopy of the localized states in a barrier. Using a simple model of three localized states, we show that, due to the Coulomb interactions, a single state can give rise to two resonant peaks in the conductance as a function of gate voltage, G(Vg). We also demonstrate that an additional higher-order resonance with Vg-position in between these two peaks becomes possibile when interactions are taken into account. The corresponding resonant-tunneling process involves two-electron transitions. We have observed both these effects in GaAs transistor microstructures by studying the time evolution of three adjacent G(Vg) peaks caused by fluctuating occupation of an isolated impurity (modulator). The heights of the two stronger peaks exibit in-phase fluctuations. The phase of fluctuations of the smaller middle peak is opposite. The two stronger peaks have their origin in the same localized state, and the third one corresponds to a co-tunneling process.Comment: 9 pages, REVTeX, 4 figure

Grotesque Inversions On Stage, In Film: Horrid Yet Curious, Fascinating Yet Alarming

Grotesque theatre is not a genre but a style of theatre made up of many strands which has been employed over many centuries beginning in Ancient Greece, particularly with Aristophanes and moving through time to the present. François Rabelais recognised the grotesque in Church Feasts, Festivals, Guild performances, sotties and farces. This thesis investigates through theatre and film the seven strands Bakhtin identifies: grotesque image, abusive language, grotesque madness, scatalogical humour, light, reversals and the lower bodily stratum (1984, pp. 24-41). In particular the thesis traces inversions in both theatre and film. These two mediums have been selected to compare and contrast the use of the grotesque in each, as they share two strong commonalities in acting and the requirement of scripts. Each chapter of this thesis deals with a script, and the last two chapters incorporate the use of a movie for contrast. The Introduction introduces the grotesque, offering an explanation of the styles of the grotesque as defined by Mikhail Bakhtin and Philip Thomson. Examples are shown in pictures. Chapter one explores two plays written by Eugene Ionesco: Amedée or How to Get Rid of It, and Rhinoceros. Chapter two moves back through time to Aristophanes' Lysistrata and explores the power women's bodies might have when men are in need. The third chapter investigates The Roaring Girl, written by Middleton and Dekker. This delves into the life of the character Moll Cutpurse and shows why Moll chose to dress as a man. Chapters four and five deal with the fantasy and the gothic elements in Frankenstein and Dracula respectively: focusing on bodily transformations; as well as the treatment of the monster and Dracula by society, and their treatment in turn of society. The grotesque is an intriguing style of theatre because it deals essentially with human nature and the human body in its imperfect and ever-changing form. The grotesque therefore lends itself to horror, comedy and exaggeration making it a style which does not have to be limited by strict parameters. The grotesque can be successfully woven into other genres such as the gothic or the absurd giving it even greater dimensions in storytelling, staging and special effects. Human beings are often torn between the gory or visually disturbing whilst needing the safety of the normal and acceptable. The grotesque offers both, which can make a scintillating piece of entertainment by fulfilling our needs at both ends of the emotional spectrum. Grotesque theatre therefore by its very nature is a style which will continue to exist so long as it keeps its patrons in suspense

Finite-temperature Fermi-edge singularity in tunneling studied using random telegraph signals

We show that random telegraph signals in metal-oxide-silicon transistors at millikelvin temperatures provide a powerful means of investigating tunneling between a two-dimensional electron gas and a single defect state. The tunneling rate shows a peak when the defect level lines up with the Fermi energy, in excellent agreement with theory of the Fermi-edge singularity at finite temperature. This theory also indicates that defect levels are the origin of the dissipative two-state systems observed previously in similar devices.Comment: 5 pages, REVTEX, 3 postscript figures included with epsfi

Acoustic Phonon-Assisted Resonant Tunneling via Single Impurities

We perform the investigations of the resonant tunneling via impurities embedded in the AlAs barrier of a single GaAs/AlGaAs heterostructure. In the $I(V)$ characteristics measured at 30mK, the contribution of individual donors is resolved and the fingerprints of phonon assistance in the tunneling process are seen. The latter is confirmed by detailed analysis of the tunneling rates and the modeling of the resonant tunneling contribution to the current. Moreover, fluctuations of the local structure of the DOS (LDOS) and Fermi edge singularities are observed.Comment: accepted in Phys. Rev.

Effect of the Coulomb repulsion on the {\it ac} transport through a quantum dot

We calculate in a linear response the admittance of a quantum dot out of equilibrium. The interaction between two electrons with opposite spins simultaneously residing on the resonant level is modeled by an Anderson Hamiltonian. The electron correlations lead to the appearence of a new feature in the frequency dependence of the conductance. For certain parameter values there are two crossover frequencies between a capacitive and an inductive behavior of the imaginary part of the admittance. The experimental implications of the obtained results are briefly discussed.Comment: 13 pages, REVTEX 3.0, 2 .ps figures from [email protected], NUB-308