Modelling distributed lag effects in epidemiological time series studies

The paper argues that much of the existing literature on air pollution and mortality deals only with the transient effects of air pollution. Policy, on the other hand, needs to know when, whether and to what extent pollution-induced increases in mortality are reversed. This involves modelling the entire distributed lag effects of air pollution. Borrowing from econometrics this paper presents a method by which distributed lag effects can be estimated parsimoniously but plausibly estimated. The paper presents a time series study into the relationship between ambient levels of air pollution and daily mortality counts for Manchester employing this technique. Black Smoke is shown to have a highly significant effect on mortality counts in the short term. Nevertheless we find that 80 percent of the deaths attributable to BS would have occurred anyway within one week whereas the remaining 20 percent of individuals would otherwise have enjoyed a normal life expectancy

Fear and perceived likelihood of victimization in the traditional and cyber settings

This study considers the influence of perceived likelihood, demographics (gender and education) and personality on fear of victimization and cyber-victimization using a survey design (N=159). The results suggest that perceived likelihood of victimization predicts fear of victimization in traditional contexts. Women tend to be more fearful of victimization in traditional and cyber contexts, confirming previous research. No group differences emerged in relation to education. Self-esteem and self-efficacy were not significant predictors of fear or perceived likelihood of victimization. However, perceived likelihood was a significant predictor of fear of victimization in traditional settings. This may suggest that different variables (such as awareness of vulnerability) may play a role in fear of victimization in cyber settings. Further group comparisons revealed that fear of victimization and cybervictimization depended on whether or not participants reported high or low perceived likelihood of victimization and internet use. Higher internet use was associated with greater fear of victimization, especially in combination with greater perceived likelihood of victimization. This may suggest an exposure effect, in that being online more frequently may also increase awareness of cyber incidents

Modelling distributed lag effects in mortality and air pollution studies: the case of Santiago

Most of the epidemiological literature on air pollution and mortality deals only with single or dual pollutant models whose results are hard to interpret and of questionable value from the policy perspective. In addition, much of the existing literature deals only with the very short-term effects of air pollution whereas policy makers need to know when, whether and to what extent pollution-induced increases in mortality counts are reversed. This involves modelling the infinite distributed lag effects of air pollution. Borrowing from econometrics this paper presents a method by which the infinite distributed lag effects can be estimated parsimoniously but plausibly estimated. The paper presents a time series study into the relationship between ambient levels of air pollution and daily mortality counts for Santiago employing this technique which confirms that the infinite lag effects are highly significant. It is also shown that day to day variations in NO2 concentrations and in the concentrations of both fine and coarse particulates are associated with short-term variations in death rates. These findings are made in the context of a model that simultaneously includes six different pollutants. Evidence is found pointing to the operation of a very short term harvesting effect

The amenity value of the Italian climate

The hedonic price literature suggests that locations with more favourable characteristics should display compensating wage and house price differentials. Estimates of the marginal willingness to pay for small changes in climate variables are derived using the hedonic price technique applied to Italian data. A hedonic price model was specified in terms of January and July averages. There exists considerable empirical support for the hypothesis that amenity values for climate are embedded in the labour and housing market. Italians would prefer a drier climate during the winter months, but higher summertime temperatures are shown to reduce welfare. These results may have relevance to the task of determining the economic impact of future climate change

Growing dust grains in protoplanetary discs - I. Radial drift with toy growth models

In a series of papers, we present a comprehensive analytic study of the global motion of growing dust grains in protoplanetary discs, addressing both the radial drift and the vertical settling of the particles. Here we study how the radial drift of dust particles is affected by grain growth. In a first step, toy models in which grain growth can either be constant, accelerate or decelerate are introduced. The equations of motion are analytically integrable and therefore the grains dynamics is easy to understand. The radial motion of growing grains is governed by the relative efficiency of the growth and migration processes which is expressed by the dimensionless parameter Lambda, as well as the exponents for the gas surface density and temperature profiles, denoted p and q respectively. When Lambda is of order unity, growth and migration are strongly coupled, providing the most efficient radial drift. For the toy models considered, grains pile up when -p+q+1/2<0. Importantly, we show the existence of a second process which can help discs to retain their solid materials. For accelerating growth, grains end up their migration at a finite radius, thus avoiding being accreted onto the central star.Comment: 12 pages, 9 figures. Accepted for publication in MNRAS. v2: typos correcte

Comparisons of real output in manufacturing

This study is concerned with the conceptual and measurement problems which arise in comparisons of levels of per capita output and productivity in different countries. The author stresses the reliance of standarized valuations of the different elements of output rather than official exchange rates when making comparisons. Two approaches are noted; (1) the expenditure approach and (2) the production approach. The production approach, discussed here, looks at the industry of origin and provides a basis for growth accounting, comparative structural analysis, studies of technological performance, and work on labor productivity and total factor productivity. This approach provides a sounder base for constructing relative indicators of productivity. It also reveals trade protection policies and their incidence on different sectors of the economy. The approach shows which data are anomalous and which analytically useful in industrial census. It also shows how new insights might be gained by exploiting some official sources which often remain untapped by international agencies.Environmental Economics&Policies,Access to Markets,Markets and Market Access,Economic Theory&Research,Banks&Banking Reform

Climate and Happiness

Climate is an important input to many human activities. Climate affects heating and cooling requirements, determines clothing and nutritional needs and limits recreational activities. As such it is to be expected that individuals will have a preference for particular types of climate. These preferences have indeed been observed using a variety of approaches including regional analyses of wage rates and land prices, the propensity to migrate, and analyses based on household consumption patterns. Mindful of existing research this paper analyses a panel of 67 countries attempting to explain differences in self-reported levels of happiness by reference to amongst other things temperature and precipitation. Various indices are used for each of these variables including means, extremes and number of months with a particular climate like the number of hot and cold months. Using a panel-corrected least squares approach the paper demonstrates that, even when controlling for a range of other factors, climate variables have a particularly powerful effect on self reported levels of happiness. Furthermore there is a correspondence between the findings that emerge from this analysis and earlier studies with respect to what constitutes a preferred climate. The relationship between climate and self reported happiness is of particular interest because of the much discussed threat of anthropogenically induced climate change. Differential patterns of warming along with a changed distribution of rainfall promises to alter dramatically the distribution of happiness between nations with some countries moving towards a preferred climate and others moving further away. We find that higher mean temperatures in the coldest month increase happiness, whereas higher mean temperatures in the hottest month decrease happiness. Precipitation does not significantly affect happiness. In particular high latitude countries included in our dataset might benefit from temperature changes. Countries already characterized by very high summer temperatures would most likely suffer losses from climate change.amenity value, climate change, happiness, well-being

Phase transition in the globalization of trade

Globalization processes interweave economic structures at a worldwide scale, trade playing a central role as one of the elemental channels of interaction among countries. Despite the significance of such phenomena, measuring economic globalization still remains an open problem. More quantitative treatments could improve the understanding of globalization at the same time that help a formal basis for comparative economic history. In this letter, we investigate the time evolution of the statistical properties of bilateral trade imbalances between countries in the trade system. We measure their cumulative probability distribution at different moments in time to discover a sudden transition circa 1960 from a regime where the distribution was always represented by a steady characteristic function to a new state where the distribution dilates as time goes on. This suggests that the rule that was governing the statistical behavior of bilateral trade imbalances until the 60's abruptly changed to a new form persistent in the last decades. In the new regime, the figures for the different years collapse into a universal master curve when rescaled by the corresponding global gross domestic product value. This coupling points to an increased interdependence of world economies and its onset corresponds in time with the starting of the last globalization wave.Comment: Final versio