A sub-sector approach to cost-benefit analysis: Small-scale sisal processing in Tanzania

project appraisal; cost-benefit analysis, sisal decorticating technology,rural innovations

Phase-slip flux qubits

In thin superconducting wires, phase-slip by thermal activation near the critical temperature is a well-known effect. It has recently become clear that phase-slip by quantum tunnelling through the energy barrier can also have a significant rate at low temperatures. In this paper it is suggested that quantum phase-slip can be used to realize a superconducting quantum bit without Josephson junctions. A loop containing a nanofabricated very thin wire is biased with an externally applied magnetic flux of half a flux quantum, resulting in two states with opposite circulating current and equal energy. Quantum phase-slip should provide coherent coupling between these two macroscopic states. Numbers are given for a wire of amorphous niobium-silicon that can be fabricated with advanced electron beam lithography.Comment: Submitted to New Journal of Physics, special issue solid state quantum informatio

Ageing effects around the glass and melting transitions in poly(dimethylsiloxane) visualized by resistance measurements

The process of ageing in rubbers requires monitoring over long periods (days to years). To do so in non-conducting rubbers, small amounts of carbon-black particles were dispersed in a fractal network through the rubber matrix, to make the rubber conducting without modifying its properties. Continuous monitoring of the resistance reveals the structural changes around the glass and melting transitions and especially details about the hysteresis and ageing processes. We illustrate the method for the semicrystalline polymer poly(dimethylsiloxane) (PDMS).Comment: 4 pages, 4 figure

Evaluating irreversible social harms

In this paper we investigate how irreversible social harms should be evaluated from an ethical perspective. First, we define a general notion of irreversibility, drawing on discussions in ecology and economics. This notion is relational in the sense that 'irreversibility' is always 'irreversibility for a certain party'. We also note that a change may be more or less difficult to reverse, with full reversibility and irreversibility as two extremes. Second, we examine what can make an irreversible change a harm, and why these kinds of harms have particular ethical significance. Here we draw on discussions from ethics, particularly regarding the Capability Approach. We also show how our notion of irreversibility connects to, and can add to, discussions in the fields of development studies and disaster management, particularly on the concept of resilience. Third, we suggest how potentially irreversible harms can be recognised and dealt with in policy-making. Finally, we show how our framework can be applied by evaluating the land acquisition process of two biofuel producers in Tanzania

How to assess the external validity of therapeutic trials: a conceptual approach

Background External validity of study results is an important issue from a clinical point of view. From a methodological point of view, however, the concept of external validity is more complex than it seems to be at first glance. Methods Methodological review to address the concept of external validity. Results External validity refers to the question whether results are generalizable to persons other than the population in the original study. The only formal way to establish the external validity would be to repeat the study for that specific target population. We propose a three-way approach for assessing the external validity for specified target populations. (i) The study population might not be representative for the eligibility criteria that were intended. It should be addressed whether the study population differs from the intended source population with respect to characteristics that influence outcome. (ii) The target population will, by definition, differ from the study population with respect to geographical, temporal and ethnical conditions. Pondering external validity means asking the question whether these differences may influence study results. (iii) It should be assessed whether the study's conclusions can be generalized to target populations that do not meet all the eligibility criteria. Conclusion Judging the external validity of study results cannot be done by applying given eligibility criteria to a single target population. Rather, it is a complex reflection in which prior knowledge, statistical considerations, biological plausibility and eligibility criteria all have plac

Lipolytic sensitivity to catecholamines in patients with human immunodeficiency virus infection

Lipolysis is higher in patients with acquired immunodeficiency syndrome (AIDS) than in healthy control subjects. To evaluate whether this increase in lipolysis is related to increased beta-adrenergic sensitivity, we compared the lipolytic response to epinephrine (approximately 15 ng x kg(-1) x min(-1)) of six AIDS patients with that of six matched control subjects. Lipolysis was measured by infusion of [2H2]glycerol and [2H2]palmitate. The baseline rates of appearance of palmitate (2.06 +/- 0.21 compared with 1.45 +/- 0.07 micromol x kg(-1) x min(-1)) and glycerol (2.35 +/- 0.16 compared with 1.35 +/- 0.06 micromol x kg(-1) x min(-1)) were higher in AIDS patients (P <0.05). The absolute increase in lipolysis, an indicator of the responsiveness to epinephrine, was not different between groups for the rate of appearance of palmitate (86 +/- 14 compared with 75 +/- 7 micromol x L(-1) x min(-1)) or glycerol (79 +/- 13 compared with 59 +/- 6 micromol x L(-1) x min(-1)). Plasma concentrations of epinephrine were not different between groups. Lipolysis was higher whereas the lipolytic response to epinephrine was normal in AIDS patients. Increased lipolytic sensitivity to catecholamines is not the cause of increased lipolysis in AID

Dissolution of metal precipitates in multicrystalline silicon during annealing and the protective effect of phosphorus emitters

The degradation of the carrier lifetime in multicrystalline silicon due to the dissolution of metal precipitates during high temperature annealing is well known. This letter presents evidence indicating that the presence of phosphorus emitters during annealing can help reduce this recontamination. Part of the degradation observed is due to increased interstitial iron concentrations caused by the dissolution of iron precipitates during annealing. However, dissolution of other metals also seems to contribute to the reduced carrier lifetimes observed.The authors would like to acknowledge the Australian Research Council for funding this work

Critical temperature oscillations in magnetically coupled superconducting mesoscopic loops

We study the magnetic interaction between two superconducting concentric mesoscopic Al loops, close to the superconducting/normal phase transition. The phase boundary is measured resistively for the two-loop structure as well as for a reference single loop. In both systems Little-Parks oscillations, periodic in field are observed in the critical temperature Tc versus applied magnetic field H. In the Fourier spectrum of the Tc(H) oscillations, a weak 'low frequency' response shows up, which can be attributed to the inner loop supercurrent magnetic coupling to the flux of the outer loop. The amplitude of this effect can be tuned by varying the applied transport current.Comment: 9 pages, 7 figures, accepted for publication in Phys. Rev.

An impact assessment methodology for small scale renewable energy projects in developing countries funded under Dutch policies defined to contribute to the millennium development goals

Vulnerable groups, such as poor people in developing countries, are often hit hard by the effects of climate change since they lack the resources needed to cope or adapt to the changing environment. To conduct poverty reduction without compromising on the environment, the Dutch government defined a variety of policy measures. One is the so‐called Daey Ouwens Fund, established to implement small scale renewable energy projects in the poorest countries of the world. This Fund aims to contribute to Millennium Developing Goal 1, eradication of extreme poverty, and MDG 7, ensuring environmental sustainability. This paper describes the methodology developed to get a better understanding of the socioeconomic and environmental impact of projects to be implemented under the Daey Ouwens Fund. This methodology uses the multi level “Strategic Niche Management (SNM)” framework to systematically assess drivers and barriers crucial in process of innovation. For three selected projects, indicators are defined within this SNM framework, based on the MGD 1 and MGD 7 and the local socio‐economic situation as well as the existing energy system and the innovative renewable energy technology of the project. These indicators are translated into sets of questions to be quantified through a limited number of semi‐structured interviews with key persons and questionnaire inquiries of a large number of potential end‐users. The data of the conducted baseline study will be presented in this paper to provide an overall picture of the current socio‐economic situation and the energy consumption in the areas were the three selected project are going to be implemented. Based on these data and the SNM framework, an overview will be provided of drivers and barriers for the projects and the expected contribution to MDG 1 and 7. The methodology will be assessed and adapted for the impact monitoring assessment that will be held in 2013