21,392 research outputs found

    Analysing Government Decision Making in the South African Biofuels Industry: A Game Theoretic Approach

    Get PDF
    The production of biofuels in many countries is largely driven by the government strategy and incentives that are in place. In South Africa the first round of the development of such a draft strategy took place in 2005 while the official stance on biofuels was finalized in December of 2007. During the policy development process various governmental departments had strategic goals and targets that they all were required to achieve. The achievement of these strategic targets and goals is also risky and the various departments that have some form of involvement in the biofuels industry need to decide on how much risk they are willing to take. This article sketches the game that the various governmental departments played as well as the risks that they were faced with when writing the Industrial Biofuels Strategy. In establishing a Nash Equilibrium and when comparing this to the current state of affairs in the industry an investigation is launched as to what has caused the governmental department to divert so strongly from this position. A variable Z is defined and included in the model in order to explain the current state of affairs. The Z variable is also analyzed further in order to bring some form of structure to the debate on the government’s stance on the issue.Biofuels, Game Theory, Government Strategy, Agricultural and Food Policy, Research Methods/ Statistical Methods,

    Characterization of a new iron-on-zeolite Y Fischer-Tropsch catalyst

    Get PDF
    Iron pentacarbonyl adsorbed on dry Na-Y zeolite can be oxidized at subambient temperatures into Fe203 located in the zeolite supercages (catalyst I). When catalyst I is hydrogen reduced at 575 K most of the iron has agglomerated externally to the zeolite (catalyst 11). When the iron carbonyl is thermally decomposed in vacuo at 525 K, an iron phase with a very low degree of dispersion is again obtained (catalyst 111). During a Fischer-Tropsch reaction most of the iron is transformed into a Hagg-type carbide phase, located externally to the zeolite. Catalysts I1 and 111 rapidly reach steady state and show a Schulz-Flory-type of product distribution, the Hagg carbide being the active phase. Catalyst I slowly moves to steady state and Schulz-Flory behavior. Product selectivity is only found on this catalyst during transient conditions. The physical information on the three catalysts before and after reaction was obtained with transmission electron microscopy and Mossbauer and EXAFS spectroscopies. These techniques supplied consistent and complementary evidenc

    Scale as a Transaction Cost Variable in the U.S. Biopower Industry

    Get PDF
    With increasing interest in renewable energy from agriculture, including biopower and cellulose ethanol, several aspects of the industry must be understood. Study of the organization of the biopower industry represents an under researched area and a new application of transaction cost theory to an emerging industry. Refinement of the theory can also result from challenging applications. This article provides an application of transaction cost economics to the existing United States biopower industry while challenging the empirical convention of excluding production cost variables from transaction cost analysis. Utilizing survey data from 53 biopower generators, scale is modeled as a transaction cost variable in explaining the choice of organizational from. Consistent with transaction cost theory, the probability of observing internal organization is found to be negatively correlated to scale. Given this evidence, this article reconsiders the impact of scale and transaction costs on the choice of organizational from.Resource /Energy Economics and Policy,

    Sub-matrix updates for the Continuous-Time Auxiliary Field algorithm

    Full text link
    We present a sub-matrix update algorithm for the continuous-time auxiliary field method that allows the simulation of large lattice and impurity problems. The algorithm takes optimal advantage of modern CPU architectures by consistently using matrix instead of vector operations, resulting in a speedup of a factor of 8\approx 8 and thereby allowing access to larger systems and lower temperature. We illustrate the power of our algorithm at the example of a cluster dynamical mean field simulation of the N\'{e}el transition in the three-dimensional Hubbard model, where we show momentum dependent self-energies for clusters with up to 100 sites

    Do Childhood Vaccines Have Non-Specific Effects on Mortality

    Get PDF
    A recent article by Kristensen et al. suggested that measles vaccine and bacille Calmette–Guérin (BCG) vaccine might\ud reduce mortality beyond what is expected simply from protection against measles and tuberculosis. Previous reviews of the potential effects of childhood vaccines on mortality have not considered methodological features of reviewed studies. Methodological considerations play an especially important role in observational assessments, in which selection factors for vaccination may be difficult to ascertain. We reviewed 782 English language articles on vaccines and childhood mortality and found only a few whose design met the criteria for methodological rigor. The data reviewed suggest that measles vaccine delivers its promised reduction in mortality, but there is insufficient evidence to suggest a mortality benefit above that caused by its effect on measles disease and its sequelae. Our review of the available data in the literature reinforces how difficult answering these considerations has been and how important study design will be in determining the effect of specific vaccines on all-cause mortality.\u

    'If I cannot access services then there is no reason for me to test': the impact of health service charges on HIV testing and treatment amongst migrants in England

    Get PDF
    Policy governing entitlement to access government health care for foreign nationals in England is a subject of debate, controversy and confusion. Of particular concern to health providers has been the impact of National Health Service charges on delaying HIV testing and anti-retroviral treatment uptake and adherence amongst certain migrant groups. Data obtained through focus groups with 70 migrants from southern Africa, suggest that confusion over health care entitlements exists amongst those seeking health care and is reported amongst health service providers. This confusion, as well as financial difficulties and fears over deportation facing some migrants, can in turn be a factor influencing their decisions to avoid formal health services, resort to alternative and often ineffective or potentially adverse forms of therapy, and delay HIV testing and treatment uptake

    A multidisciplinary survey of modeling techniques for biochemical networks

    Get PDF
    All processes of life are dominated by networks of interacting biochemical components. The purpose of modeling these networks is manifold. From a theoretical point of view it allows the exploration of network structures and dynamics, to find emergent properties or to explain the organization and evolution of networks. From a practical point of view, in silico experiments can be performed that would be very expensive or impossible to achieve in the laboratory, such as hypothesis-testing with regard to knockout experiments or overexpression, or checking the validity of a proposed molecular mechanism. The literature on modeling biochemical networks is growing rapidly and the motivations behind different modeling techniques are sometimes quite distant from each other. To clarify the current context, we present a systematic overview of the different philosophies to model biochemical networks. We put particular emphasis on three main domains which have been playing a major role in the past, namely: mathematics with ordinary and partial differential equations, statistics with stochastic simulation algorithms, Bayesian networks and Markov chains, and the field of computer science with process calculi, term rewriting systems and state based systems. For each school, we evaluate advantages and disadvantages such as the granularity of representation, scalability, accessibility or availability of analysis tools. Following this, we describe how one can combine some of those techniques and thus take advantages of several techniques through the use of bridging tools. Finally, we propose a next step for modeling biochemical networks by using artificial chemistries and evolutionary computation. This work was funded by ESIGNET (Evolving Cell Signaling Networks in Silico), an European Integrated Project in the EU FP6 NEST Initiative (contract no. 12789)

    Managing expectations and fiscal policy

    Get PDF
    This paper studies an optimal fiscal policy problem of Lucas and Stokey (1983) but in a situation in which the representative agent's distrust of the probability model for government expenditures puts model uncertainty premia into history-contingent prices. This situation gives rise to a motive for expectation management that is absent within rational expectations and a novel incentive for the planner to smooth the shadow value of the agent's subjective beliefs to manipulate the equilibrium price of government debt. Unlike the Lucas and Stokey (1983) model, the optimal allocation, tax rate, and debt become history dependent despite complete markets and Markov government expenditures.
    corecore