What was the programme theory of New Labour’s health system reforms?

To examine whether the Health System Reforms delivered the promise of being a coherent and mutually supporting reform programme; to identify the underlying programme theory of the reform programme; to reflect on whether lessons have been learned. \ud \ud Documentary analysis mapping the implicit and explicit programme theories about how the reforms intended to achieve its goals and outcomes. Semi-structured interviews with policy-makers to further understand the programme theory. \ud \ud The Health System Reforms assumed a ‘one size fits all’ approach to policy implementation with little recognition that some contexts can be more receptive than others. There was evidence of some policy evolution and rebalancing between the reform streams as policy-makers became aware of some perverse incentives and unforeseen consequences. Later elements aimed to restore balance to the system. \ud \ud The Health System Reforms do not appear to comprise a coherent and mutually supportive set of levers and incentives. They appear unbalanced with the centre of gravity favouring suppliers over commissioners. However, recent reform changes have sought to redress this imbalance to some extent, suggesting that lessons have been learned and policies have been adapted over time

Quantum frustration in organic Mott insulators: from spin liquids to unconventional superconductors

We review the interplay of frustration and strong electronic correlations in quasi-two-dimensional organic charge transfer salts, such as k-(BEDT-TTF)_2X and Et_nMe_{4-n}Pn[Pd(dmit)2]2. These two forces drive a range of exotic phases including spin liquids, valence bond crystals, pseudogapped metals, and unconventional superconductivity. Of particular interest is that in several materials there is a direct transition as a function of pressure from a spin liquid Mott insulating state to a superconducting state. Experiments on these materials raise a number of profound questions about the quantum behaviour of frustrated systems, particularly the intimate connection between spin liquids and superconductivity. Insights into these questions have come from a wide range of theoretical techniques including first principles electronic structure, quantum many-body theory and quantum field theory. In this review we introduce the basic ideas of the field by discussing a simple frustrated Heisenberg model with four spins. We then describe the key experimental results, emphasizing that for two materials, k-(BEDT-TTF)_2Cu_2(CN)_3 and EtMe_3Sb[Pd(dmit)_2]_2, there is strong evidence for a spin liquid ground state, and for EtMe_3P[Pd(dmit)_2]_2, a valence bond solid ground state. We review theoretical attempts to explain these phenomena, arguing that this can be captured by a Hubbard model on the anisotropic triangular lattice at half filling, and that resonating valence bond wavefunctions can capture most of the essential physics. We review evidence that this model can have a spin liquid ground state for a range of parameters that are realistic for the relevant materials. We conclude by summarising the progress made thus far and identifying some of the key questions still to be answered.Comment: Major rewrite. New material added and many typos corrected. 67 pages, 41 figures. Thanks to those who commented on the previous versio

Symmetry of the superconducting order parameter in frustrated systems determined by the spatial anisotropy of spin correlations

We study the resonating valence bond (RVB) theory of the Hubbard-Heisenberg model on the half-filled anisotropic triangular lattice. Varying the frustration changes the wavevector of maximum spin correlation in the Mott insulating phase. This, in turn, changes the symmetry of the superconducting state, that occurs at the boundary of the Mott insulating phase. We propose that this physics is realised in several families of quasi-two-dimensional organic superconductors.Comment: To appear in Phys. Rev. Lett. - 5 pages, 4 fig

Market Manipulation and a Case for the Further Regulation of Social Media and the Finance Industry

This paper intends to investigate the potential of market manipulation in under regulated markets that does not exist in regulated ones. I do this by looking at the previous literature discovered on ambiguity aversion, and how it is linked to the increase of social media’s effect on price changes in markets. I investigate two different markets that are regulated and unregulated. These markets are the US stock exchange and the cryptocurrency market. I then see what the effect that twitter has on the two over the same periods of time using the most up-to-date models. Finally, I recommend policy changes that will help prevent market manipulation of under regulated markets

Interplay of frustration, magnetism, charge ordering, and covalency in a model of Na0.5CoO2

We investigate an effective Hamiltonian for Na0.5CoO2 that includes the electrostatic potential due to the ordered Na ions and strong electronic correlations. This model displays a subtle interplay between metallic and insulating phases and between charge and magnetic order. For realistic parameters, the model predicts an insulating phase with similarities to a covalent insulator. We show that this interpretation gives a consistent explanation of experiments on Na0.5CoO2, including the small degree of charge ordering, the small charge gap, the large moment, and the optical conductivity.Comment: 5 pages, 4 figures. Text revised making more emphasis on model properties. Figures compacte

Sensitivity of the photo-physical properties of organometallic complexes to small chemical changes

We investigate an effective model Hamiltonian for organometallic complexes that are widely used in optoelectronic devices. The two most important parameters in the model are $J$, the effective exchange interaction between the $\pi$ and $\pi^*$ orbitals of the ligands, and $\epsilon^*$, the renormalized energy gap between the highest occupied orbitals on the metal and on the ligand. We find that the degree of metal-to-ligand charge transfer (MLCT) character of the lowest triplet state is strongly dependent on the ratio $\epsilon^*/J$. $\epsilon^*$ is purely a property of the complex and can be changed significantly by even small variations in the complex's chemistry, such as replacing substituents on the ligands. We find that that small changes in $\epsilon^*/J$ can cause large changes in the properties of the complex, including the lifetime of the triplet state and the probability of injected charges (electrons and holes) forming triplet excitations. These results give some insight into the observed large changes in the photophysical properties of organometallic complexes caused by small changes in the ligands.Comment: Accepted for publication in J. Chem. Phys. 14 pages, 9 figures, Supplementary Info: 15 pages, 17 figure

Spin Fluctuations and the Pseudogap in Organic Superconductors

We show that there are strong similarities in the spin lattice relaxation of non-magnetic organic charge transfer salts, and that these similarities can be understood in terms of spin fluctuations. Further, we show that, in all of the kappa-phase organic superconductors for which there is nuclear magnetic resonance data, the energy scale for the spin fluctuations coincides with the energy scale for the pseudogap. This suggests that the pseudogap is caused by short-range spin correlations. In the weakly frustrated metals k-(BEDT-TTF)_2Cu[N(CN)_2]Br, k-(BEDT-TTF)_2Cu(NCS)_2, and k-(BEDT-TTF)_2Cu[N(CN)_2]Cl (under pressure) the pseudogap opens at the same temperature as coherence emerges in the (intralayer) transport. We argue that this is because the spin correlations are cut off by the loss of intralayer coherence at high temperatures. We discuss what might happen to these two energy scales at high pressures, where the electronic correlations are weaker. In these weakly frustrated materials the data is well described by the chemical pressure hypothesis (that anion substitution is equivalent to hydrostatic pressure). However, we find important differences in the metallic state of k-(BEDT-TTF)_2Cu_2(CN)_3, which is highly frustrated and displays a spin liquid insulating phase. We also show that the characteristic temperature scale of the spin fluctuations in (TMTSF)_2ClO_4 is the same as superconducting critical temperature, which may be evidence that spin fluctuations mediate the superconductivity in the Bechgaard salts.Comment: 7 pages, 4 figures; to appear in PR

Pre and post fire carbon dynamics in a Florida Scrub oak

Scrub oak is a xeromorphic shrub ecosystem discontinuously distributed in coastal and inland Florida. It supports a high biodiversity which includes a large number of endangered and threatened species. Its structural features are maintained by a fire return cycle of 7 to 10 years which maintains the biodiversity. Management of fire prone ecosystems such as this raises the question of whether the management strategy contributes to the system being a carbon sink or carbon source over the long-term. We used eddy covariance and biometric approaches to measure carbon dynamics in a Florida scrub oak ecosystem located at Kennedy Space Center in east Central Florida from April 2004 to December 2007. The study site was controlled burned in February 2006. Two years previous to fire, the site experienced average precipitation but drought conditions during the two years after fire. Net ecosystem production (NEP) was 419 g C m-2 yr-1 during the first year of measurements, and the ecosystem incorporated 823 g C m-2 during the 22 months before the fire. Aboveground net primary production (NPP) represented 50% of annual NEP. Carbon released by fire reached 316 g C m-2. Ecosystem respiration (Re) dominated the carbon balance during the first six months after fire, and the ecosystem released an extra 119 g C m-2. However, gross ecosystem production (GEP) increased with leaf area index (LAI) after fire, dominating the carbon balance during the following six months. The ecosystem was a carbon sink of 88 g C m-2 yr-1 during the first year after the fire. Leaf area index (LAI) reached 1.54 m2 m-2 by October 2007 (80% of pre-burn value for the same time period). The scrub oak ecosystem was a continuous carbon sink six months after the fire despite the dominant drought conditions during 2006 – 2007. The ecosystem offset 80% (251 g C m-2) of the carbon released in the fire during the following twenty two months after the fire. Considering the fire return cycle of 7 to 10 years and the fact that the study site and a similar site nearby incorporated more than 400 g C m-2 yr-1 during the two years before fire, this scrub oak is a net carbon sink in the landscape under current management strategies

Marine Benthic Habitat Mapping of Muir Inlet, Glacier Bay National Park and Preserve, Alaska With an Evaluation of the Coastal and Marine Ecological Classification Standard III

Seafloor geology and potential benthic habitats were mapped in Muir Inlet, Glacier Bay National Park and Preserve, Alaska, using multibeam sonar, ground-truth information, and geological interpretations. Muir Inlet is a recently deglaciated fjord that is under the influence of glacial and paraglacial marine processes. High glacially derived sediment and meltwater fluxes, slope instabilities, and variable bathymetry result in a highly dynamic estuarine environment and benthic ecosystem. We characterize the fjord seafloor and potential benthic habitats using the Coastal and Marine Ecological Classification Standard (CMECS) recently developed by the National Oceanic and Atmospheric Administration (NOAA) and NatureServe. Substrates within Muir Inlet are dominated by mud, derived from the high glacial debris flux. Water-column characteristics are derived from a combination of conductivity temperature depth (CTD) measurements and circulation-model results. We also present modern glaciomarine sediment accumulation data from quantitative differential bathymetry. These data show Muir Inlet is divided into two contrasting environments: a dynamic upper fjord and a relatively static lower fjord. The accompanying maps represent the first publicly available high-resolution bathymetric surveys of Muir Inlet. The results of these analyses serve as a test of the CMECS and as a baseline for continued mapping and correlations among seafloor substrate, benthic habitats, and glaciomarine processes