The effect of reionization on the COBE normalization

We point out that the effect of reionization on the microwave anisotropy power spectrum is not necessarily negligible on the scales probed by COBE. It can lead to an upward shift of the COBE normalization by more than the one-sigma error quoted ignoring reionization. We provide a fitting function to incorporate reionization into the normalization of the matter power spectrum.Comment: 3 pages LaTeX file with three figures incorporated (uses mn.sty and epsf

Cosmic microwave background constraints on the epoch of reionization

We use a compilation of cosmic microwave anisotropy data to constrain the epoch of reionization in the Universe, as a function of cosmological parameters. We consider spatially-flat cosmologies, varying the matter density $\Omega_0$ (the flatness being restored by a cosmological constant), the Hubble parameter $h$ and the spectral index $n$ of the primordial power spectrum. Our results are quoted both in terms of the maximum permitted optical depth to the last-scattering surface, and in terms of the highest allowed reionization redshift assuming instantaneous reionization. For critical-density models, significantly-tilted power spectra are excluded as they cannot fit the current data for any amount of reionization, and even scale-invariant models must have an optical depth to last scattering of below 0.3. For the currently-favoured low-density model with $\Omega_0 = 0.3$ and a cosmological constant, the earliest reionization permitted to occur is at around redshift 35, which roughly coincides with the highest estimate in the literature. We provide general fitting functions for the maximum permitted optical depth, as a function of cosmological parameters. We do not consider the inclusion of tensor perturbations, but if present they would strengthen the upper limits we quote.Comment: 9 pages LaTeX file with ten figures incorporated (uses mn.sty and epsf). Corrects some equation typos, superseding published versio

Inflation and the cosmic microwave background

I give a status report and outlook concerning the use of the cosmic microwave background anisotropies to constrain the inflationary cosmology, and stress its crucial role as an underlying paradigm for the estimation of cosmological parameters.Comment: 8 pages LaTeX file, with two figures incorporated using epsf. To appear, proceedings of `The non-sleeping universe', Porto (Astrophysics and Space Science

Teaching controversial issues: Talking about religious freedom and the imagined ‘other’

Symposium: Teaching Controversial Issues Lee Jerome, Judy Pace, Helen Young, Sally Elton-Chalcraft and Anna Liddle The call to tackle controversial issues in citizenship, history, and other social studies disciplines increases as the world faces greater social, political, and economic crises (Kerr & Huddleston, 2015). Teachers’ ability to frame issues and their relevant content knowledge, utilize effective pedagogies, and create a supportive atmosphere is essential (Hahn, 1998). Controversial issues are "those problems and disputes that divide society and for which significant groups within society offer conflicting explanations and solutions based on alternative values" (Stradling et al., 1984, p. 2). They include public issues, related, for example, to terrorism, reproductive rights, and immigration (Hess, 2009), and sensitive questions related to contested histories (Foster, 2014) such as the partition of Ireland and culpability for genocide. Research shows that the discussion of controversial issues in an open classroom climate develops political knowledge and engagement (Hess & McAvoy, 2015) as well as tolerance (Avery, 2002). But teaching them successfully requires a particular set of knowledge, skills, and dispositions (Hess, 2009). Identifying an issue as controversial may be controversial itself (Camicia, 2008) and issues considered intensely controversial in some countries (e.g. gay marriage, collective health care) may be less so in others, and issues become more or less controversial over time (Hess, 2009). Therefore, teaching controversial issues often involves risk-taking (Kitson & McCully, 2005). Curricular resources and pedagogical structures can assist greatly, but school curriculum, culture, and policy can impede teachers’ efforts. In this symposium we share recent research that explores curricular, pedagogic, and policy implications of pursuing open explorations of controversial issues. Paper 1: Learning to teach controversial issues: Developmental and Contextual Factors How do preservice teachers learn to teach controversial issues in citizenship, social studies, and history? What factors support and constrain their risk-taking? This paper takes up Kitson & McCully’s (2005) continuum of risk-taking and reports findings from a study on preparing preservice teachers to teach controversial issues, conducted in Northern Ireland, England, and the United States. Out of 15 interviewed, 12 creatively used tools from their methods courses to teach lessons that made students explore different perspectives on an important issue. The novices practiced "contained risk-taking" (Author): They espoused social aims but only some taught to these aims. They used provocative resources but critical examination of them was minimal. They used dialogic pedagogies but sustained discussion was limited. Linkages between history and current concerns close to home were made in Northern Ireland but not in England. Factors that supported or constrained risk-taking included curriculum, timetables, students, mentor teachers, and school culture. The paper discusses implications for teacher education and school policy. Paper 2: Enabling young people to build their understanding of terrorism and extremism? A review of resources. This paper reviews the teaching resources on the Educate Against Hate website (DfE, on-line), which has been developed by the UK government ‘to provide practical advice, support and resources to protect children from extremism and radicalisation.’ The paper considers the resources in relation to research which has previously indicated what young people say they want and need (e.g. Jerome & Elwick, 2019), exploring their provenance; their adoption of counter-narratives; their levels of bias; their avoidance of issues; and their overall coherence. The paper concludes that the resources fall significantly short of young people’s expectations and often represent simplistic and uncritical counter-narratives. It argues that a genuinely educational approach will take more heed of young people’s opinions, and engage in a more critical exploration of the issues in order to support young people to build their understanding and make sense of their world post-9/11. Paper 3: Talking about religious freedom and the imagined ‘other’ This paper reports on student discussions in small groups and whole class plenaries related to religious freedom and toleration. We reflect on the ways in which students engaged with the stimulus material offered to them and illustrate how they often used their imagination to move significantly beyond the facts they were given. We argue this reflects a playful commitment to develop cognitive empathy and de-centre their discussions through forms of thought experiment, and that this therefore reflects the need to recognise the legitimate other in such debates. Our findings have implications for whether / how the fundamental British values should be taught more critically as controversial issues

A Thallium Mediated Route to \u3cem\u3eσ\u3c/em\u3e-Arylalkynyl Complexes of Bipyridyltricarbonylrhenium(I)

A simple, one-pot preparation of rhenium(I) σ-arylalkynyl complexes is reported using thallium(I) hexafluorophosphate as a halogen abstraction agent. This new route to rhenium σ-alkynyls enjoys higher yields compared to analogous preparations using silver salts by eliminating potential electrochemical degradation pathways

What can the observation of nonzero curvature tell us?

The eternally inflating multiverse provides a consistent framework to understand coincidences and fine-tuning in the universe. As such, it provides the possibility of finding another coincidence: if the amount of slow-roll inflation was only slightly more than the anthropic threshold, then spatial curvature might be measurable. We study this issue in detail, particularly focusing on the question: "If future observations reveal nonzero curvature, what can we conclude?" We find that whether an observable signal arises or not depends crucially on three issues: the cosmic history just before the observable inflation, the measure adopted to define probabilities, and the nature of the correlation between the tunneling and slow-roll parts of the potential. We find that if future measurements find positive curvature at \Omega_k < -10^-4, then the framework of the eternally inflating multiverse is excluded with high significance. If the measurements instead reveal negative curvature at \Omega_k > 10^-4, then we can conclude (1) diffusive (new or chaotic) eternal inflation did not occur in our immediate past; (2) our universe was born by a bubble nucleation; (3) the probability measure does not reward volume increase; and (4) the origin of the observed slow-roll inflation is an accidental feature of the potential, not due to a theoretical mechanism. Discovery of \Omega_k > 10^-4 would also give us nontrivial information about the correlation between tunneling and slow-roll; e.g. a strong correlation favoring large N would be excluded in certain measures. We also ask whether the current constraint on \Omega_k is consistent with multiverse expectations, finding that the answer is yes, except for certain cases. In the course of this work we were led to consider vacuum decay branching ratios, and found that it is more likely than one might guess that the decays are dominated by a single channel.Comment: 46 pages, 5 figures; reference updates and typo corrections arising from final Phys. Rev. D copy editin

Triple unification of inflation, dark matter, and dark energy using a single field

We construct an explicit scenario whereby the same material driving inflation in the early Universe can comprise dark matter in the present Universe, using a simple quadratic potential. Following inflation and preheating, the density of inflaton/dark matter particles is reduced to the observed level by a period of thermal inflation, of a duration already invoked in the literature for other reasons. Within the context of the string landscape, one can further argue for a non-zero vacuum energy of this field, thus unifying inflation, dark matter and dark energy into a single fundamental field.Comment: 5 pages RevTeX with 3 figures incorporate

Inflation, dark matter and dark energy in the string landscape

We consider the conditions needed to unify the description of dark matter, dark energy and inflation in the context of the string landscape. We find that incomplete decay of the inflaton field gives the possibility that a single field is responsible for all three phenomena. By contrast, unifying dark matter and dark energy into a single field, separate from the inflaton, appears rather difficult.Comment: 4 pages RevTex4. Updated to include a toy model of reheating. Matches version accepted by Phys Rev Let

Utilisation of native wildlife by Indigenous Australians: Commercial considerations

This paper is based on a submission to the Senate Rural and Regional Affairs and Transport References Committee Inquiry into the commercial use of Australian native wildlife. It uses secondary sources and is also based on primary research. - Indigenous Australians have a special interest in commercial utilisation of wildlife due to their subsistence activities, religious associations with many species, present and future rights to tracts of land under land rights legislation and, potentially, following the passage of the Native Title Act. - Indigenous people's interest is also based in their growing involvement in sustainable utilisation of species for ecotourism and their desire to become less economically dependent on government support. - Indigenous people desire input into species management to ensure maintenance of biodiversity. - Aboriginal people have few economic opportunities in remote communities and are seeking further commercial opportunities in wildlife enterprises. However, past experience of Indigenous enterprises is chequered due to locational, cultural and human capital constraints. - Marketing and other problems associated with wildlife products hamper present enterprises. There are few data on the impact of commercial utilisation or subsistence usage of species. The research recommends that: - In the best interests of commercial utilisation of wildlife in a sustainable manner, there is a need for an enhanced role for Indigenous interests in species management. This could be achieved through their Indigenous organisations and via joint management processes. This is necessary because many species are endemic to Aboriginal-owned land that accounts for 17 per cent of Australia. Some precedents exist in joint management of inhabited national parks particularly in the Northern Territory. - It is essential to achieve a balance between subsistence use, commercialisation and preservation of wildlife, taking into account possible tradeoffs with the commercial value of tourism based on the non-harvesting of species. Opportunities are greatest for Indigenous people when harvesting is from the wild, rather than by farming species. -Joint ventures, royalty arrangements, property rights in species and joint management plans also offer opportunities for Indigenous people to become involved in commercial utilisation and management of wildlife. - Given the limited economic opportunities of remote Aboriginal communities, there is a need to explore options to convert Indigenous leverage with respect to species to their advantage. If commercial wildlife use is to expand, it is important that Indigenous people have equal opportunities to participate in it, and that expansion by non-Indigenous interests does not hamper the subsistence and commercial options available to Indigenous people. Joint-venturing, possibly with non-Indigenous partners, is an important means that must be considered to enable Indigenous people to participate in the economic benefits from commercial utilisation of wildlife. - Another issue requiring investigation in the aftermath of native title legislation is whether there is a need (or statutory requirement) to recognise existing and potential Indigenous property rights in species. Indirect options to attract rents from utilisation of wildlife, either via direct involvement as joint venturers or as sellers of property rights in species, need to be assessed as a way to provide financial returns to Indigenous communities. -There is a need to recognise that from the Indigenous perspective, in some situations, subsistence utilisation of species may make greater economic sense than commercial utilisation. In other words, the 'outstation gate' market replacement value of species used for subsistence may exceed their monetary market price

Can the Gravitational Wave Background from Inflation be Detected Locally?

The Cosmic Background Explorer (COBE) detection of microwave background anisotropies may contain a component due to gravitational waves generated by inflation. It is shown that the gravitational waves from inflation might be seen using `beam-in-space' detectors, but not the Laser Interferometer Gravity Wave Observatory (LIGO). The central conclusion, dependent only on weak assumptions regarding the physics of inflation, is a surprising one. The larger the component of the COBE signal due to gravitational waves, the {\em smaller} the expected local gravitational wave signal.Comment: 8 pages, standard LaTeX (no figures), SUSSEX-AST 93/7-