Cosmological Constraints from Primordial Black Holes

Primordial black holes may form in the early Universe, for example from the collapse of large amplitude density perturbations predicted in some inflationary models. Light black holes undergo Hawking evaporation, the energy injection from which is constrained both at the epoch of nucleosynthesis and at the present. The failure as yet to unambiguously detect primordial black holes places important constraints. In this article, we are particularly concerned with the dependence of these constraints on the model for the complete cosmological history, from the time of formation to the present. Black holes presently give the strongest constraint on the spectral index $n$ of density perturbations, though this constraint does require $n$ to be constant over a very wide range of scales.Comment: 8 pages LaTeX file, using elsart.sty, with three figures incorporated using epsf. To appear, proceedings of DM98, Los Angeles (ed D Cline, Elsevier

Charge shelving and bias spectroscopy for the readout of a charge-qubit on the basis of superposition states

Charge-based qubits have been proposed as fundamental elements for quantum computers. One commonly proposed readout device is the single-electron transistor (SET). SETs can distinguish between localized charge states, but lack the sensitivity to directly distinguish superposition states, which have greatly enhanced coherence times compared with position states. We propose introducing a third dot, and exploiting energy dependent tunnelling from the qubit into this dot (bias spectroscopy) for pseudo-spin to charge conversion and superposition basis readout. We introduce an adiabatic fast passage-style charge pumping technique which enables efficient and robust readout via charge shelving, avoiding problems due to finite SET measurement time.Comment: 4 pages, 3 figures, note slightly changed title, replaced with journal versio

Primordial black holes and early cosmology

We describe the changes to the standard primordial black hole constraints on density perturbations if there are modifications to the standard cosmology between the time of formation and nucleosynthesis.Comment: 5 pages LaTeX file, using sprocl.sty, with three figures incorporated using epsf. To appear, proceedings of Cosmo-97, Ambleside (ed L Roszkowski, World Scientific

Interventions at the Supreme Court of Canada: Accuracy, Affiliation, and Acceptance

Interveners make submissions in about half of the cases heard by the Supreme Court of Canada, but the motivations for and consequences of the practice are not clearly understood. Considered broadly, there are at least three functions that the practice of intervention might perform. The first possibility is that hearing from interveners might provide objectively useful information to the Court (i.e., interveners might promote the accuracy of the Court\u27s decision making). A second possibility is that the practice of intervention allows interveners to provide the best argument for certain partisan interests that judges might want to affiliate with. A third possibility is that interventions are allowed mainly (if not only) so that intervening parties feel they have had their voices heard by the Court and the greater public, including Parliament, regardless of the effect on the outcome of the appeal (i.e., the Court might be promoting the acceptability of its decisions by allowing for an outlet for expression). We examine empirically the role of interveners in all the cases decided by the Supreme Court of Canada from January 2000 to July 2009 and find statistical evidence that interveners matter

Influence of association state and DNA binding on the O2-reactivity of [4Fe-4S] fumarate and nitrate reduction (FNR) regulator

The fumarate and nitrate reduction (FNR) regulator is the master switch for the transition between anaerobic and aerobic respiration in Escherichia coli. Reaction of dimeric [4Fe-4S] FNR with O2 results in conversion of the cluster into a [2Fe-2S] form, via a [3Fe-4S] intermediate, leading to the loss of DNA binding through dissociation of the dimer into monomers. In the present paper, we report studies of two previously identified variants of FNR, D154A and I151A, in which the form of the cluster is decoupled from the association state. In vivo studies of permanently dimeric D154A FNR show that DNA binding does not affect the rate of cluster incorporation into the apoprotein or the rate of O2-mediated cluster loss. In vitro studies show that O2-mediated cluster conversion for D154A and the permanent monomer I151A FNR is the same as in wild-type FNR, but with altered kinetics. Decoupling leads to an increase in the rate of the [3Fe-4S]1+ into [2Fe-2S]2+ conversion step, consistent with the suggestion that this step drives association state changes in the wild-type protein. We have also shown that DNA-bound FNR reacts more rapidly with O2 than FNR free in solution, implying that transcriptionally active FNR is the preferred target for reaction with O2

Heroic Helping: The Effects of Priming Superhero Images on Prosociality

Two experiments examined how exposure to superhero images influences both prosociality and meaning in life. In Experiment 1 (N = 246) exposed individuals to scenes with superhero images or neutral images. Individuals primed with superhero images reported greater helping intentions relative to the control group, which, in turn, were associated with increased meaning in life (indirect effect only; no direct effect). In Experiment 2 (N = 123), individuals exposed to a superhero poster helped an experimenter in a tedious task more than those exposed to a bicycle poster, though no differences were found for meaning in life. These results suggest that subtle activation of superhero stimuli increases prosocial intentions and behavior

Black Hole Condensation and the Unification of String Vacua

It is argued that black hole condensation can occur at conifold singularities in the moduli space of type II Calabi--Yau string vacua. The condensate signals a smooth transition to a new Calabi--Yau space with different Euler characteristic and Hodge numbers. In this manner string theory unifies the moduli spaces of many or possibly all Calabi--Yau vacua. Elementary string states and black holes are smoothly interchanged under the transitions, and therefore cannot be invariantly distinguished. Furthermore, the transitions establish the existence of mirror symmetry for many or possibly all Calabi--Yau manifolds.Comment: 15 pages, harvma

Creative writing in A level English literature

This is an Author's Accepted Manuscript of an article published in New Writing: The International Journal for the Practice and Theory of Creative Writing, 6(3), 187 - 195, 2009, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/14790720903556155.This is a time of change and real development for creative writing at A level. Whilst it has been an important part of English Language and English Language & Literature A level specifications for some time, its presence within English Literature has been marginal, and is an option that has rarely been adopted by teachers of the subject. Recent changes to English Literature specifications, however, mean that creative writing (along with recreative and transformative writing) now exists in a much more formalised way on all A level English Literature specifications. As the largest of the three A level Englishes, this is a significant development. The advent of creative writing in English Literature makes this an important issue in teachers' Continuing Professional Development (Green, 2008) and raises important questions for the teaching body in schools and lecturers in further education. What is the role of creative writing in teaching literature? How do creative and analytical writing relate to each other? What is the relationship between creative writing and reading? This paper offers an initial response to these and other issues, and suggests some of the ways in which creative writing can be used both in its own right and to enhance the study of English Literature at A level

Creative writing in A level English literature

This is an Author's Accepted Manuscript of an article published in New Writing: The International Journal for the Practice and Theory of Creative Writing, 6(3), 187 - 195, 2009, copyright Taylor & Francis, available online at: http://www.tandfonline.com/10.1080/14790720903556155.This is a time of change and real development for creative writing at A level. Whilst it has been an important part of English Language and English Language & Literature A level specifications for some time, its presence within English Literature has been marginal, and is an option that has rarely been adopted by teachers of the subject. Recent changes to English Literature specifications, however, mean that creative writing (along with recreative and transformative writing) now exists in a much more formalised way on all A level English Literature specifications. As the largest of the three A level Englishes, this is a significant development. The advent of creative writing in English Literature makes this an important issue in teachers' Continuing Professional Development (Green, 2008) and raises important questions for the teaching body in schools and lecturers in further education. What is the role of creative writing in teaching literature? How do creative and analytical writing relate to each other? What is the relationship between creative writing and reading? This paper offers an initial response to these and other issues, and suggests some of the ways in which creative writing can be used both in its own right and to enhance the study of English Literature at A level