The Political Economy of Low-carbon Investments: Insights from the Wind and Solar Power Sectors in India

The primary motivation behind this research is the need to accelerate the supply of renewable energy because of the important role that it plays in mitigating climate change and in fostering sustainable development. Understanding past drivers for low-carbon investment can help us identify those for the future, and what could accelerate such investment. Investment in renewable energy can be modelled as a problem of technical asset allocation or optimisation at the firm or sectoral level, but is not entirely explained by this approach – the context in which actors are involved, their motivations and the wider systems in which they operate must also be taken into account. The interactions between actors may sometimes accelerate investment and sometimes prevent it; however, understanding the dynamics of these processes is crucial if we are to shape them. This study, which focuses on the wind and solar power sectors in India and China, aims to find and compare drivers for investment in renewable energy. Our point of entry for this piece of the study is that India is already seeing significant investment activity in renewable energy. During 2010/11, investment in renewables grew by 62 per cent to US$13bn (although it slowed drastically in 2011/12 to US$6.5bn). In 2010 the Indian government announced a National Solar Mission that aimed to add 20 gigawatts (GW) of solar power generation capacity by 2020; wind power capacity has grown steadily at a compound annual growth rate of 17.9 per cent since 2007 and now contributes more than 20GW, or just over 70 per cent, of total renewable energy capacity. Almost all of this is private investment. However, these levels will need to increase sharply in the coming years and decades if India is to reach China’s levels (who, in 2013, became the world leader with US$67bn invested in renewables) and make a greater contribution to the US$1tn needed.UK Department for International Developmen

Reprint of “Pharmacokinetic modelling of the anti-malarial drug artesunate and its active metabolite dihydroartemisinin”

A four compartment mechanistic mathematical model is developed for the pharmacokinetics of the commonly used anti-malarial drug artesunate and its principle metabolite dihydroartemisinin following oral administration of artesunate. The model is structurally unidentifiable unless additional constraints are imposed. Combinations of mechanistically derived constraints are considered to assess their effects on structural identifiability and on model fits. Certain combinations of the constraints give rise to locally or globally identifiable model structures. Initial validation of the model under various combinations of the constraints leading to identifiable model structures was performed against a dataset of artesunate and dihydroartemisinin concentration–time profiles of 19 malaria patients. When all the discussed constraints were imposed on the model, the resulting globally identifiable model structure was found to fit reasonably well to those patients with normal drug absorption profiles. However, there is wide variability in the fitted parameters and further investigation is warranted

TeV scale resonant leptogenesis from supersymmetry breaking

We propose a model of TeV-scale resonant leptogenesis based upon recent models of the generation of light neutrino masses from supersymmetry-breaking effects with TeV-scale right-handed (rhd) neutrinos, $N_i$. The model leads to naturally large cosmological lepton asymmetries via the resonant behaviour of the one-loop self-energy contribution to $N_i$ decay. Our model addresses the primary problems of previous phenomenological studies of low-energy leptogenesis: a rational for TeV-scale rhd neutrinos with small Yukawa couplings so that the out-of equilibrium condition for $N_i$ decay is satisfied; the origin of the tiny, but non-zero mass splitting required between at least two $N_i$ masses; and the necessary non-trivial breaking of flavour symmetries in the rhd neutrino sector. The low mass-scale of the rhd neutrinos and their superpartners, and the TeV-scale $A$-terms automatically contained within the model offer opportunities for partial direct experimental tests of this leptogenesis mechanism at future colliders.Comment: 10 Pages latex, version for JHE

Pharmacokinetic modelling of the anti-malarial drug artesunate and its active metabolite dihydroartemisinin

A four compartment mechanistic mathematical model is developed for the pharmacokinetics of the commonly used anti-malarial drug artesunate and its principle metabolite dihydroartemisinin following oral administration of artesunate. The model is structurally unidentifiable unless additional constraints are imposed. Combinations of mechanistically derived constraints are considered to assess their effects on structural identifiability and on model fits. Certain combinations of the constraints give rise to locally or globally identifiable model structures. Initial validation of the model under various combinations of the constraints leading to identifiable model structures was performed against a dataset of artesunate and dihydroartemisinin concentration–time profiles of 19 malaria patients. When all the discussed constraints were imposed on the model, the resulting globally identifiable model structure was found to fit reasonably well to those patients with normal drug absorption profiles. However, there is wide variability in the fitted parameters and further investigation is warranted

Generalised Israel Junction Conditions for a Gauss-Bonnet Brane World

In spacetimes of dimension greater than four it is natural to consider higher order (in R) corrections to the Einstein equations. In this letter generalized Israel junction conditions for a membrane in such a theory are derived. This is achieved by generalising the Gibbons-Hawking boundary term. The junction conditions are applied to simple brane world models, and are compared to the many contradictory results in the literature.Comment: 4 page

Distinguishing WH and WBBbar production at the Fermilab Tevatron

The production of a Higgs boson in association with a W-boson is the most likely process for the discovery of a light Higgs at the Fermilab Tevatron. Since it decays primarily to b-quark pairs, the principal background for this associated Higgs production process is WBBbar, where the BBbar pair comes from the splitting of an off mass shell gluon. In this paper we investigate whether the spin angular correlations of the final state particles can be used to separate the Higgs signal from the WBBbar background. We develop a general numerical technique which allows one to find a spin basis optimized according to a given criterion, and also give a new algorithm for reconstructing the W longitudinal momentum which is suitable for the WH and WBBbar processes.Comment: latex, 12 pages, 19 postscript figure

Temporal fluctuations of waves in weakly nonlinear disordered media

We consider the multiple scattering of a scalar wave in a disordered medium with a weak nonlinearity of Kerr type. The perturbation theory, developed to calculate the temporal autocorrelation function of scattered wave, fails at short correlation times. A self-consistent calculation shows that for nonlinearities exceeding a certain threshold value, the multiple-scattering speckle pattern becomes unstable and exhibits spontaneous fluctuations even in the absence of scatterer motion. The instability is due to a distributed feedback in the system "coherent wave + nonlinear disordered medium". The feedback is provided by the multiple scattering. The development of instability is independent of the sign of nonlinearity.Comment: RevTeX, 15 pages (including 5 figures), accepted for publication in Phys. Rev.

Spanning forests and the q-state Potts model in the limit q \to 0

We study the q-state Potts model with nearest-neighbor coupling v=e^{\beta J}-1 in the limit q,v \to 0 with the ratio w = v/q held fixed. Combinatorially, this limit gives rise to the generating polynomial of spanning forests; physically, it provides information about the Potts-model phase diagram in the neighborhood of (q,v) = (0,0). We have studied this model on the square and triangular lattices, using a transfer-matrix approach at both real and complex values of w. For both lattices, we have computed the symbolic transfer matrices for cylindrical strips of widths 2 \le L \le 10, as well as the limiting curves of partition-function zeros in the complex w-plane. For real w, we find two distinct phases separated by a transition point w=w_0, where w_0 = -1/4 (resp. w_0 = -0.1753 \pm 0.0002) for the square (resp. triangular) lattice. For w > w_0 we find a non-critical disordered phase, while for w < w_0 our results are compatible with a massless Berker-Kadanoff phase with conformal charge c = -2 and leading thermal scaling dimension x_{T,1} = 2 (marginal operator). At w = w_0 we find a "first-order critical point": the first derivative of the free energy is discontinuous at w_0, while the correlation length diverges as w \downarrow w_0 (and is infinite at w = w_0). The critical behavior at w = w_0 seems to be the same for both lattices and it differs from that of the Berker-Kadanoff phase: our results suggest that the conformal charge is c = -1, the leading thermal scaling dimension is x_{T,1} = 0, and the critical exponents are \nu = 1/d = 1/2 and \alpha = 1.Comment: 131 pages (LaTeX2e). Includes tex file, three sty files, and 65 Postscript figures. Also included are Mathematica files forests_sq_2-9P.m and forests_tri_2-9P.m. Final journal versio

The adolescent HIV executive function and drumming (AHEAD) study, a feasibility trial of a group drumming intervention amongst adolescents with HIV

AHEAD feasibility trial assessed the feasibility and acceptability of an 8-session group drummingprogramme aiming to improve executive function, depression and anxiety symptoms, andperceived social support in adolescents living with HIV in a rural low-income South Africansetting. Sixty-eight 12- to 19-year-old adolescents participated. They were individuallyrandomised. The intervention arm (n= 34) received weekly hour-long group drumming sessions.Controls (n= 34) received no intervention. Feasibility and acceptability were assessed usingrates of: enrolment; retention; attendance; logistical problems; adolescent-reportedacceptability. Secondary measures included:five Oxford Cognitive Screen-Executive Function(OCS-EF) tasks; two Rapid Assessment of Cognitive and Emotional Regulation (RACER) tasks; theSelf-Reporting Questionnaire-20 (SRQ-20) measuring depression and anxiety symptoms; theMultidimensional Scale of Perceived Social Support (MSPSS). All feasibility criteria were withingreen progression limits. Enrolment, retention, and acceptability were high. There was a positive effect on adolescent depressed mood with a signal for a working memory effect. There were no significant effects on executive function or socio-emotional scales. Qualitative findings suggested socio-emotional benefits including group belonging; decreased internalised stigma; improved mood; and decreased anxiety. Group drumming is a feasible and acceptable intervention among adolescents living with HIV in rural South Africa. A full-scale trial is recommendedAfrica-Oxford Initiative (AfiOx-32), the Society for Education, Music and Psychology Research (SEMPRE) Gerry Farrell scholarship, the Murray Speight grant, the Rhodes Trust, and the Medical Research Council United Kingdom.https://www.tandfonline.com/loi/caic20Musi