Autocatalytic sets in a partitioned biochemical network

In previous work, RAF theory has been developed as a tool for making theoretical progress on the origin of life question, providing insight into the structure and occurrence of self-sustaining and collectively autocatalytic sets within catalytic polymer networks. We present here an extension in which there are two "independent" polymer sets, where catalysis occurs within and between the sets, but there are no reactions combining polymers from both sets. Such an extension reflects the interaction between nucleic acids and peptides observed in modern cells and proposed forms of early life.Comment: 28 pages, 8 figure

The New Consensus in Monetary Policy: Is the NKM fit for the purpose of inflation targeting?

In this paper we examine whether or not the NKM is .t for the purpose of providing a suitable basis for the conduct of monetary policy through inflation targeting. We focus on a number of issues: the dynamic response of inflation to interest rates in a theoretical NKM under discretion and commitment to a Taylor rule; the implications for the specification of the New Keynesian Phillips equation of alternative models of imperfect competition in a closed and an open economy; the general equilibrium underpinnings of the IS function; the extent of empirical support for the NKM; what the empirical evidence on the NKM implies for inflation targeting. Our findings reveal a number of problems with the NKM. Theoretically, the NKM predicts that a discretionary increase in interest rates will increase inflation, not reduce it. This is supported by our VAR evidence. Estimates of the NKM indicate a negative relation between interest rates and inflation, but the signs in the structural equations are inconsistent with the theory. We conclude that the standard specifications of the inflation and output equations are inadequate and that these equations should be embedded in a larger model.Inflation targeting, monetary policy, New Keynesian model

Summer of Code: Assisting Distance-Learning Students with Open-Ended Programming Tasks

A significant difficulty in teaching programming lies in the transition from novice to intermediate programmer, characterised by the assimilation and use of schemas of standard programming approaches. A significant factor assisting this transition is practice with tasks which develop this schema use. We describe the Summer of Code, a two-week activity for part-time, distance-learning students which gave them some additional programming practice. We analysed their submissions, forum postings, and results of a terminal survey. We found learners were keen to share and discuss their solutions and persevered with individual problems and the challenge overall. 93% respondents rated the activity 3 or better on a 5-point Likert scale (n=58). However, a quarter of participants, mainly those who described themselves as average or poor programmers, felt less confident in their abilities after the activity, though half of these students liked the activity overall. 54% of all participants said the greatest challenge was developing a general approach to the problems, such as selecting appropriate data structures. This is corroborated by forum comments, where students greatly appreciated “think aloud” presentations by faculty tackling the problems. These results strongly suggest that students would benefit from more open-ended practice, where they have to select and design their own solutions to a range of problems

Use of economic evidence in the design of Health Improvement Programmes (HImPs)

Introduction 1. In recent years considerable efforts have been made to increase the evidence base for decision making within the NHS. Under the NHS R&D Programme a sizeable percentage of NHS resources have been spent on research, one of the largest programmes of research being in the field of health technology assessment. 2. However, whilst the generation of more research evidence is important, mechanisms still need to be developed to increase its use in NHS decision making. The NHS White Paper of 1997 (paragraph 7.5) pointed out that “there are unjustifiable variations in the application of evidence on clinical and cost-effectiveness”. 3. The concept of the Health Improvement Programme (HImP) was first introduced in “The New NHS. Modern: Dependable” (NHS Executive, 1997). This white paper gave the lead responsibility to health authorities to provide a framework for health and social care provision through multi-agency partnership and in collaboration with the public. One of the main aims of the HImP is to produce action plans based on evidence to address local and national priorities. HImPs cover a three year long cycle and are revised annually. The second phase HImPs ran from April 2000 to April 2003 and these are the focus of this project. 4. To date, a small number of reviews of HImPs have been conducted (Abbott et al, 2000, Arora et at 1999 & 2000, Carruthers et al, 1999) but there has been limited exploration of the role of evidence in relation to the HImP, and no specific effort has been made to examine whether the HImP has proved to be a useful vehicle in arranging provision of care to improve the health of the population, given resource constraints. This report explores the evidence base of these second phase HImPs with particular reference to the contribution of economic evidence. Methods 5. In order to examine the use of evidence in the design of HImPs, a threestage project was undertaken. First, a survey of all English health authorities was conducted to elicit HImP leaders’ views on the use of evidence in the design of their own HImP. Second, 10 individuals involved in the HImP and who worked for different health authorities were interviewed to explore their views on the HImP, the role of evidence and the impact of the HImP. Third, a random sample of 25% of all 2000-2003 HImP documents from the health authorities in England were reviewed in order to investigate whether the health care priorities chosen reflect government objectives and whether there was any evidence of the use of economic evidence in the production of the HImP documents. Findings 6. The main findings were that, first, HImPs are seen as having multiple objectives. Whereas the improvement of health is viewed as the prime objective, other important objectives are to reduce health inequalities and to develop partnerships. 7. Second, the notion of evidence is interpreted broadly. Namely, data drawn from classical research studies and published in the literature, do not encompass the range of inputs to the design of a HImP. Many of the inputs relate to national guidance and local professional opinion, which in turn might be based on data from research studies. 8. Third, basic concepts of economics are well understood, if not always applied. This is partly because the level of access to economic analyses and economics expertise was low. Even where economic studies did exist, it was not clear how they could be interpreted and used. 9. Fourth, local constraints greatly influence the development of HImPs. These constraints include time limitations, lack of certain expertise and the need for political acceptability. These often restricted the extent of the search for, interpretation and use of economic evidence. 10. Finally, most importantly, national guidance from National Service Frameworks (NSFs) and the National Institute for Clinical Excellence (NICE) s very influential in the design of HImPs. Given the constraints at the local level, national guidance was assumed to have a sound evidence base and was usually followed, although sometimes adapted in the light of local circumstances. Therefore, the use of national guidance may be the best route to improving the evidence base of HImPs. Research and policy implications 11. The results of this research lend considerable support to a number of research and policy implications, many of which are already underway. The ain implications are: (i) the evidence base of national guidance should be maintained, if not strengthened; (ii) efforts should continue to generate, synthesise and disseminate evidence on a national level; (iii) quantifiable targets (for health improvement) and the role for evidence in priority setting need to be stressed; (iv) the local role in assembling evidence needs to be clearly defined and adequately resourced; (v) efforts to educate health care professionals in evidence-based medicine and economics should be maintained, or strengthened; (vi) more research should be undertaken into the cost-effectiveness of broader socio-economic interventions to improve health. 12. Finally, the research and policy implications of this study also need to be reviewed in the light of the recently announced organisational changes in the NHS, especially the creation of strategic health authorities and the developing role of PCGs/Ts. In particular, it will be important to ensure that PCGs/Ts have the resources and expertise to gather, synthesise and interpret evidence, including economic evidence. Introduction In recent years considerable efforts have been made to increase the evidence base for decision making within the NHS. Under the NHS R&D Programme a sizeable percentage of NHS resources have been spent on research, one of the largest programmes of research being in the field of health technology assessment. In addition, institutions such as the NHS Centre for Reviews and Dissemination, the Cochrane Collaboration and the National Coordinating Centre for Health Technology Assessment have greatly contributed to the communication of research findings to the NHS. The NHS white paper of 1997 (para 7.5) pointed out that “there are unjustifiable variations in the application of evidence on clinical and cost-effectiveness” (NHS Executive, 1997). This view is echoed by several surveys of NHS decision-makers (Crump et al, 2000, Drummond et al, 1997; Duthie et al, 1999) which showed a generally low uptake of available economic evidence and dentified a number of barriers to its use. At the national level, the advent of the National Institute of Clinical Excellence (NICE) (DH, 1999) provides a vehicle by which clinical and cost-effectiveness evidence can be used in decisions about the use of health care interventions, either through technology appraisal or clinical guidelines development. However, at the local level, within the NHS, it is less clear how appropriate evidence (in particular economic evidence) can be brought to bear on NHS decisions. Under the existing structure, many of the decisions about the use of health care interventions will increasingly be taken by Primary Care Groups (PCGs) and rimary Care Trusts (PCTs). However, most of these will be too small to have a capacity to collect, assimilate and apply evidence. The health authorities’ main mechanism for coordinating health care provision, in partnership with PCGs/PCTs, NHS Trusts and other agencies is the Health Improvement Programme (HImP). Therefore, the objective of the research was to study HImPs in order to investigate the extent to which evidence, in particular economic evidence, had been used in their development.HImP

Modelling the long-term benefits of photodynamic therapy (PDT) with Verteporfin for age-related macular degeneration (AMD)

Age related macular degeneration (AMD) is the leading cause of blindness in the United Kingdom and the rest of the western world. It occurs in 15% to 30% of individuals over 75 years of age. About 15% of these patients develop a more aggressive wet form of the disease that causes severe loss of vision. This report contains estimates of the benefits of photodynamic therapy (PDT) with verteporfin therapy using a modeling approach based on clinical trial data. While this report covers only the effects of the treatment, the model built was customizable so that it could be populated with local cost data. This made it possible to use the model to help inform local formulary decisions.clinical trial, blindness, vision

Macroeconmic Sources of FOREX Risk.

This paper considers the problem of measuring macroeconomic sources of financial risk. 1. It aims to provide a general theory of asset pricing suitable for taking account of macroeconomic sources of risk. Stochastic discount factor theory is used to provide the theoretical framework. This is capable of embracing most of the approaches in the literature, including general equilibrium theory. Market structure needs to be added to this. 2. It is shown that many of the models used in the empirical literature of asset pricing have a fundamental flaw: they admit unlimited arbitrage opportunities. High profile suites of computer programs just produced and sold world-wide suffer the same problem, and hence should not be used. 3. Modelling the exchange rate is key to much of monetary policy (eg the Bank of England's Monetary Policy Committee), and to testing FOREX market efficiency. The forward premium puzzle lies at the heart of the difficulty of doing this. The theoretical results of this paper are used to re-examine the distribution of exchange rate movements and to try to resolve this puzzle. Stochastic discount factor theory is used to derive expressions for the risk premia for domestic and foreign investors. It is shown that these are likely to be different. A combined theory of market risk when both types of investor are trading is then obtained. The cases of complete and incomplete markets are considered. It is shown how macroeconomic sources of risk can be introduced by modelling the stochastic discount factor using observable macroeconomic variables. Three SDF models are compared: a benchmark model which provides a reformulation of traditional tests of FOREX efficiency; inter-temporal consumption-based CAPM; and the monetary model of the exchange rate, a familiar macroeconomic model of FOREX which can be interpreted as arising from traditional hedging concerns. The joint distribution of the excess return to foreign exchange and the macro factors is specified in a way that satisfies the no-arbitrage assumption. It is assumed that the joint distribution has multivariate GARCH and it is shown that to eliminate arbitrage opportunities it is necessary for the conditional distribution of the excess return to exhibit GARCH-in-mean. The omission of the conditional covariance between the excess return and the sources of risk is the reason why nearly all financial statistical packages are not suitable for use in financial econometrics. The presence of this term implies that the analysis must be conducted in a multi-variate and not a uni-variate framework. The theory admits the possibility that domestic and foreign investors may have different attitudes to risk. This is incorporated into the model by introducing a switching formulation of the conditional covariance structure. Extreme changes in exchange rates suggest that the usual assumption of log-normality may fail to capture the excess kurtosis of excess returns. The model is therefore also estimated assuming a log t-distribution. It is notoriously difficult to achieve convergence in multi-variate GARCH models, and GARCH-in-mean effects increase the difficulty. This is a major limitation in the practicality of the whole approach. It is shown that assuming constant correlation greatly simplifies the estimation without sacrificing any essential elements. Tests are conducted to enable a comparison of different SDF models, different market structures, different attitudes to risk, and differences between the SDF model and the Fama approach. The empirical work is based on monthly data for the sterling-dollar exchange rate 1975-1997. Our main new finding is that the evidence is more consistent with the FOREX risk premium arising from traditional partial equilibrium models of currency risk that form the basis of hedging than with consumption-CAPM, a general equilibrium theory. In particular, US and UK output appear to be important sources of FOREX risk.FOREX, market efficiency, risk premium, stochastic discount factors, GARCH.

A multi-INT semantic reasoning framework for intelligence analysis support

Lockheed Martin Corp. has funded research to generate a framework and methodology for developing semantic reasoning applications to support the discipline oflntelligence Analysis. This chapter outlines that framework, discusses how it may be used to advance the information sharing and integrated analytic needs of the Intelligence Community, and suggests a system I software architecture for such applications

Does welfare reform affect fertility? Evidence from the UK

In 1999 the UK government made major reforms to the system of child-contingent benefits, including the introduction of Working Families' Tax Credit and an increase in means-tested Income Support for families with children. Between 1999-2003 government spending per-child on these benefits rose by 50 per cent in real terms, a change that was unprecedented over a thirty year period. This paper examines whether there was a response in childbearing. To identify the effect of the reforms, we exploit the fact that the spending increases were targeted at low-income households and we use the (exogenously determined) education of the woman and her partner to define treatment and control groups. We argue that the reforms are most likely to have a positive fertility effect for women in couples and show that this is the case. We find that there was an increase in births (by around 15 per cent) among the group affected by the reforms.Welfare reform; fertility; Working Families Tax Credit

Does Welfare Reform Affect Fertility? Evidence from the UK

This paper presents evidence on the fertility effect of welfare from a set of reforms that took place in the UK in 1999 and that substantially increased support for poorer families with children. The reforms, including the introduction of the Working Families Tax Credit and an increase in means-tested income support, raised benefits by up to 10 per cent of household income. We exploit the fact that the reforms were targeted on low-income households and use a differences-in-differences approach to evaluate their impact on fertility. A priori, the fertility effect of the reforms is ambiguous because WFTC has pro-employment effects. In practice, these are more important for lone mothers and we therefore focus on women in couples where we expect the reforms to have a positive effect on births. We find that the reforms raised the probability of birth among women in couples by around 10 per cent (implying an elasticity of 0.22). In line with previous work, the effect is greatest for first births.Welfare reform, Fertility, Working Families Tax Credit

Origins

First the static, gray and white and endlessly in motion, dynamic and flat, so much going on with maybe no work from anyone. It’s just the tops of trees in early winter, the ends of branches thrashing in a windstorm. A cloud of gnats. The gray of the water of a restless lake, and it’s a cloudy day, and there’s rain on the water, and the drops explode the water’s surface, and that’s it..