The UK market for energy service contracts in 2014–2015

This paper provides an overview of the UK market for energy service contracts in 2014 and highlights the growing role of intermediaries. Using information from secondary literature and interviews, it identifies the businesses offering energy service contracts, the sectors and organisations that are purchasing those contracts, the types of contract that are available, the areas of market growth and the reasons for that growth. The paper finds that the UK market is relatively large, highly diverse, concentrated in particular sectors and types of site and overwhelmingly focused upon established technologies with high rates of return. A major driver is the emergence of procurement frameworks for energy service contracts in the public sector. These act as intermediaries between clients and contractors, thereby lowering transaction costs and facilitating learning. The market is struggling to become established in commercial offices, largely as a result of split incentives, and is unlikely to develop further in this sector without different business models, tenancy arrangements and policy initiatives. Overall, the paper concludes that energy service contracts can play an important role in the transition to a low-carbon economy, especially when supported by intermediaries, but their potential is still limited by high transaction costs

Nonuniversal behavior of scattering between fractional quantum Hall edges

Among the predicted properties of fractional quantum Hall states are fractionally charged quasiparticles and conducting edge-states described as chiral Luttinger liquids. In a system with a narrow constriction, tunneling of quasi-particles between states at different edges can lead to resistance and to shot noise. The ratio of the shot noise to the backscattered current, in the weak scattering regime, measures the fractional charge of the quasi-particle, which has been confirmed in several experiments. However, the non-linearity of the resistance predicted by the chiral Luttinger liquid theory was apparently not observed in some of these cases. As a possible explanation for these discrepancies, we consider a model where a smooth edge profile leads to formation of additional edge states. Coupling between the current carrying edge mode and the additional phonon like mode can lead to {\it nonuniversal} exponents in the current-voltage characteristic, while preserving the ratio between shot noise and the back-scattered current, for weak backscattering. For special values of the coupling, one may obtain a linear I-V behavior.Comment: 10 pages, 3 figure

Evidence for non-linear quasiparticle tunneling between fractional quantum Hall edges

Remarkable nonlinearities in the differential tunneling conductance between fractional quantum Hall edge states at a constriction are observed in the weak-backscattering regime. In the $\nu$ = 1/3 state a peak develops as temperature is increased and its width is determined by the fractional charge. In the range $2/3 \le \nu \le 1/3$ this width displays a symmetric behavior around $\nu$ = 1/2. We discuss the consistency of these results with available theoretical predictions for inter-edge quasiparticle tunneling in the weak-backscattering regime

Spin glass behavior in URh_2Ge_2

URh_2Ge_2 occupies an extraordinary position among the heavy-electron 122-compounds, by exhibiting a previously unidentified form of magnetic correlations at low temperatures, instead of the usual antiferromagnetism. Here we present new results of ac and dc susceptibilities, specific heat and neutron diffraction on single-crystalline as-grown URh_2Ge_2. These data clearly indicate that crystallographic disorder on a local scale produces spin glass behavior in the sample. We therefore conclude that URh_2Ge_2 is a 3D Ising-like, random-bond, heavy-fermion spin glass.Comment: 10 pages, RevTeX, with 4 postscript figures, accepted by Physical Review Letters Nov 15, 199

Analysis of Shot Noise at Finite Temperatures in Fractional Quantum Hall Edge States

We investigate shot noise at {\it finite temperatures} induced by the quasi-particle tunneling between fractional quantum Hall (FQH) edge states. The resulting Fano factor has the peak structure at a certain bias voltage. Such a structure indicates that quasi-particles are weakly {\it glued} due to thermal fluctuation. We show that the effect makes it possible to probe the difference of statistics between $\nu=1/5,{}2/5$ FQH states where quasi-particles have the same unit charge.Finally we propose a way to indirectly obtain statistical angle in hierarchical FQH states.Comment: 5 pages, 3 figure

Edge-State Velocity and Coherence in a Quantum Hall Fabry-Perot Interferometer

We investigate nonlinear transport in electronic Fabry-Perot interferometers in the integer quantum Hall regime. For interferometers sufficiently large that Coulomb blockade effects are absent, a checkerboard-like pattern of conductance oscillations as a function of dc bias and perpendicular magnetic field is observed. Edge-state velocities extracted from the checkerboard data are compared to model calculations and found to be consistent with a crossover from skipping orbits at low fields to E x B drift at high fields. Suppression of visibility as a function of bias and magnetic field is accounted for by including energy- and field-dependent dephasing of edge electrons.Comment: related papers at http://marcuslab.harvard.ed

The clinical utility of lung clearance index in early cystic fibrosis lung disease is not impacted by the number of multiple-breath washout trials

© ERS 2018. The lung clearance index (LCI) from the multiple-breath washout (MBW) test is a promising surveillance tool for pre-school children with cystic fibrosis (CF). Current guidelines for MBW testing recommend that three acceptable trials are required. However, success rates to achieve these criteria are low in children aged < 7 years and feasibility may improve with modified pre-school criteria that accepts tests with two acceptable trials. This study aimed to determine if relationships between LCI and clinical outcomes of CF lung disease differ when only two acceptable MBW trials are assessed. Healthy children and children with CF aged 3–6 years were recruited for MBW testing. Children with CF also underwent bronchoalveolar lavage fluid collection and a chest computed tomography scan. MBW feasibility increased from 46% to 75% when tests with two trials were deemed acceptable compared with tests where three acceptable trials were required. Relationships between MBW outcomes and markers of pulmonary inflammation, infection and structural lung disease were not different between tests with three acceptable trials compared with tests with two acceptable trials. This study indicates that pre-school MBW data from two acceptable trials may provide sufficient information on ventilation distribution if three acceptable trials are not possible

Statistical Properties of Cross-Correlation in the Korean Stock Market

We investigate the statistical properties of the correlation matrix between individual stocks traded in the Korean stock market using the random matrix theory (RMT) and observe how these affect the portfolio weights in the Markowitz portfolio theory. We find that the distribution of the correlation matrix is positively skewed and changes over time. We find that the eigenvalue distribution of original correlation matrix deviates from the eigenvalues predicted by the RMT, and the largest eigenvalue is 52 times larger than the maximum value among the eigenvalues predicted by the RMT. The $\beta_{473}$ coefficient, which reflect the largest eigenvalue property, is 0.8, while one of the eigenvalues in the RMT is approximately zero. Notably, we show that the entropy function $E(\sigma)$ with the portfolio risk $\sigma$ for the original and filtered correlation matrices are consistent with a power-law function, $E(\sigma) \sim \sigma^{-\gamma}$, with the exponent $\gamma \sim 2.92$ and those for Asian currency crisis decreases significantly

Density Induced Interchange of Anisotropy Axes at Half-Filled High Landau Levels

We observe density induced 90$^{\circ}$ rotations of the anisotropy axes in transport measurements at half-filled high Landau levels in the two dimensional electron system, where stripe states are proposed ($\nu$=9/2, 11/2, etc). Using a field effect transistor, we find the transition density to be $2.9\times10^{11}$cm$^{-2}$ at $\nu$=9/2. Hysteresis is observed in the vicinity of the transition. We construct a phase boundary in the filling factor-magnetic field plane in the regime $4.4<\nu<4.6$. An in-plane magnetic field applied along either anisotropy axis always stabilizes the low density orientation of the stripes.Comment: 1 revtex file, 3 eps figure

Quantum creep and variable range hopping of one-dimensional interacting electrons

The variable range hopping results for noninteracting electrons of Mott and Shklovskii are generalized to 1D disordered charge density waves and Luttinger liquids using an instanton approach. Following a recent paper by Nattermann, Giamarchi and Le Doussal [Phys. Rev. Lett. {\bf 91}, 56603 (2003)] we calculate the quantum creep of charges at zero temperature and the linear conductivity at finite temperatures for these systems. The hopping conductivity for the short range interacting electrons acquires the same form as for noninteracting particles if the one-particle density of states is replaced by the compressibility. In the present paper we extend the calculation to dissipative systems and give a discussion of the physics after the particles materialize behind the tunneling barrier. It turns out that dissipation is crucial for tunneling to happen. Contrary to pure systems the new metastable state does not propagate through the system but is restricted to a region of the size of the tunneling region. This corresponds to the hopping of an integer number of charges over a finite distance. A global current results only if tunneling events fill the whole sample. We argue that rare events of extra low tunneling probability are not relevant for realistic systems of finite length. Finally we show that an additional Coulomb interaction only leads to small logarithmic corrections.Comment: 15 pages, 3 figures; references adde