Why on earth did I buy that? A study of regretted appliance purchases

If targets to reduce greenhouse gas emissions and thereby tackle climate change are to be achieved, it will be necessary to reduce both embodied energy costs (e.g. in terms of producing and manufacturing the products and services that society consumes) and operational energy costs. Reducing the number of purchases that people regret could be a first step in changing the overall dynamic of consumption patterns. This research looks at some potentially adverse effects of consumption on well-being (e.g. negative emotions), applying social practice theory to give insights into why people make purchases that they feel negatively about. This paper draws from: (i) findings of a national survey of over 2000 respondents which found that 53% of adults had reported regretting purchasing an electrical device at some point, and that 23% regretted making such a purchase within the past year; and (ii) a series of walking interviews around people's homes that provide detailed insights into the nature and extent of regretted purchases of electrical goods (e.g. resentment at built-in obsolescence, frustration at the pace of technological change). By combining the qualitative and quantitative data, we develop a typology of regretted consumption and explore the underlying factors that lead to such purchases. The paper concludes with a discussion of the policy implications of this research

Long-range coupling of silicon photonic waveguides using lateral leakage and adiabatic passage

We present a new approach to long range coupling based on a combination of adiabatic passage and lateral leakage in thin shallow ridge waveguides on a silicon photonic platform. The approach enables transport of light between two isolated waveguides through a mode of the silicon slab that acts as an optical bus. Due to the nature of the adiabatic protocol, the bus mode has minimal population and the transport is highly robust. We prove the concept and examine the robustness of this approach using rigorous modelling. We further demonstrate the utility of the approach by coupling power between two waveguides whilst bypassing an intermediate waveguide. This concept could form the basis of a new interconnect technology for silicon integrated photonic chips

Spatial mapping of hepatitis C prevalence in recent injecting drug users in contact with services.

In developed countries the majority of hepatitis C virus (HCV) infections occur in injecting drug users (IDUs) with prevalence in IDUs often high, but with wide geographical differences within countries. Estimates of local prevalence are needed for planning services for IDUs, but it is not practical to conduct HCV seroprevalence surveys in all areas. In this study survey data from IDUs attending specialist services were collected in 52/149 sites in England between 2006 and 2008. Spatially correlated random-effects models were used to estimate HCV prevalence for all sites, using auxiliary data to aid prediction. Estimates ranged from 14% to 82%, with larger cities, London and the North West having the highest HCV prevalence. The methods used generated robust estimates for each area, with a well-identified spatial pattern that improved predictions. Such models may be of use in other areas of study where surveillance data are sparse

Modelling the costs of non-conventional oil: A case study of Canadian bitumen

Keywords JEL Classification High crude oil prices, uncertainties about the consequences of climate change and the eventual decline of conventional oil production raise the issue of alternative fuels, such as non-conventional oil and biofuels. This paper describes a simple probabilistic model of the costs of nonconventional oil, including the role of learning-by-doing in driving down costs. This forward-looking analysis quantifies the effects of both learning and production constraints on the costs of supplying bitumen which can then be upgraded into synthetic crude oil, a substitute to conventional oil. The results show large uncertainties in the future costs of supplying bitumen from Canadian oil sands deposits, with a 90% confidence interval of $8 to$12 in 2025, and $7 to$15 in 2050 (2005 US$). The influence of each parameter on the supply costs is examined, with the minimum supply cost, the learning rate, and the depletion curve exponent having the largest influence. Over time, the influence of the learning rate on the supply costs decreases, while the influence of the depletion curve exponent increases. Climate change; Non-conventional oil; Exhaustible resources; Technological change; Uncertainty

The danger of subverting students’ views in schools

This paper is firmly grounded in the position that engaging with students’ voices in schools is central to the development of inclusive practices. It explores the tensions that can be created when efforts are made to engage with students’ voices in relation to their experiences of learning and teaching. An example from a three-year research and development project, which worked alongside teachers to use students’ voices as a way of developing inclusive practices, is used to illustrate these tensions. This project, though showing that students’ voices can be a powerful means for understanding learning and teaching in schools, also encountered challenges with these processes. This paper focuses on the experiences of one secondary school which (possibly inadvertently) subverted and undermined students’ voice initiatives and explores the potential negative impacts of this on individual students, on students as a whole, and on teacher development. By doing this, suggestions as to how such tensions can be avoided in schools are offered, with the aim being to allow a genuine engagement with the views of students

Scalp cooling with adjuvant/neoadjuvant chemotherapy for breast cancer and the risk of scalp metastases: systematic review and meta-analysis.

PurposeThe risk of scalp metastases in patients using scalp cooling for preservation of hair during chemotherapy has been a concern but is poorly described.MethodsA systematic review and meta-analysis of longitudinal studies was undertaken to evaluate the effect of scalp cooling versus no scalp cooling on the risk of scalp metastasis in patients treated for breast cancer with chemotherapy. Electronic databases, journal specific, and hand searches of articles identified were searched. Patients were matched based on disease, treatment, lack of metastatic disease, and sex.ResultsA total of 24 full-text articles were identified for review. Of these articles, ten quantified the incidence of scalp metastasis with scalp cooling over time. For scalp cooling, 1959 patients were evaluated over an estimated mean time frame of 43.1 months. For no scalp cooling, 1238 patients were evaluated over an estimated mean time frame of 87.4 months. The incidence rate of scalp metastasis in the scalp cooling group versus the no scalp cooling group was 0.61% (95% CI 0.32-1.1%) versus 0.41% (95% CI 0.13-0.94%); P = 0.43.ConclusionThe incidence of scalp metastases was low regardless of scalp cooling. This analysis suggests that scalp cooling does not increase the incidence of scalp metastases

Trapped ion scaling with pulsed fast gates

Fast entangling gates for trapped ions offer vastly improved gate operation times relative to implemented gates, as well as approaches to trap scaling. Gates on neighbouring ions only involve local ions when performed sufficiently fast, and we find that even a fast gate between distant ions with few degrees of freedom restores all the motional modes given more stringent gate speed conditions. We compare pulsed fast gate schemes, defined by a timescale faster than the trap period, and find that our proposed scheme has less stringent requirements on laser repetition rate for achieving arbitrary gate time targets and infidelities well below $10^{-4}$. By extending gate schemes to ion crystals, we explore the effect of ion number on gate fidelity for coupling neighbouring pairs of ions in large crystals. Inter-ion distance determines the gate time, and a factor of five increase in repetition rate, or correspondingly the laser power, reduces the infidelity by almost two orders of magnitude. We also apply our fast gate scheme to entangle the first and last ions in a crystal. As the number of ions in the crystal increases, significant increases in the laser power are required to provide the short gate times corresponding to fidelity above 0.99.Comment: 29 pages, 10 figure

Generating controllable atom-light entanglement with a Raman atom laser system

We introduce a scheme for creating continuous variable entanglement between an atomic beam and an optical field, by using squeezed light to outcouple atoms from a BEC via a Raman transition. We model the full multimode dynamics of the atom laser beam and the squeezed optical field, and show that with appropriate two-photon detuning and two-photon Rabi frequency, the transmitted light is entangled in amplitude and phase with the outcoupled atom laser beam. The degree of entanglement is controllable via changes in the two-photon Rabi frequency of the outcoupling process.Comment: 4 pages, 4 figure