684 research outputs found

    Mitigation versus compensation in global warming policy

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    Policy discussions on global warming are focused on mitigation and adaptation. Here the role of ex post compensation as a substitute for ex ante mitigation is considered. In a simple 2-period model the salient features of the global warming problem suggest mitigation is difficult to motivate. A key problem is that damages are very hard to identify even after the fact. The roles of endogenous private savings and a compensation fund as an alternative to ex ante mitigation are explored.Climate change

    Multivariate trend comparisons between autocorrelated climate series with general trend regressors

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    Inference regarding trends in climatic data series, including comparisons across different data sets as well as univariate trend significance tests, is complicated by the presence of serial correlation and step-changes in the mean. We review recent developments in the estimation of heteroskedasticity and autocorrelation robust (HAC) covariance estimators as they have been applied to linear trend inference, with focus on the Vogelsang-Franses (2005) nonparametric approach, which provides a unified framework for trend covariance estimation robust to unknown forms of autocorrelation up to but not including unit roots, making it especially useful for climatic data applications. We extend the Vogelsang-Franses approach to allow general deterministic regressors including the case where a step-change in the mean occurs at a known date. Additional regressors change the critical values of the Vogelsang-Franses statistic. We derive an asymptotic approximation that can be used to simulate critical values. We also outline a simple bootstrap procedure that generates valid critical values and p-values. The motivation for extending the Vogelsang-Franses approach is an application that compares climate model generated and observational global temperature data in the tropical lower- and mid-troposphere from 1958 to 2010. Inclusion of a mean shift regressor to capture the Pacific Climate Shift of 1977 causes apparently significant observed trends to become statistically insignificant, and rejection of the equivalence between model generated and observed data trends occurs for much smaller significance levels (i.e. is more strongly rejected).Autocorrelation; trend estimation; HAC variance matrix; global warming; model comparisons

    Does air pollution cause respiratory illness? A new look at Canadian cities

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    It is routinely asserted that urban air pollution is a major cause of acute respiratory conditions, leading to thousands of hospitalizations each year. The claim is based on inferences from partial correlations between ambient air pollution levels and hospitalization rates. Yet questions persist about the statistical robustness of the epidemiological findings, and controlled experiments have not confirmed the statistical findings. In this paper we present and analyze a new monthly data base showing concentrations of five major air contaminants in 11 large Canadian cities from 1974 to 1994, matched with monthly hospital admission rates by age group for all lung diagnostic categories; as well as a comprehensive set of socioeconomic and meteorological covariates. We compare two estimation approaches: model selection and Bayesian model averaging. Almost all of our estimates of the health effects of air pollution are insignificant. Two pollutant types have significantly negative coefficients, indicating, if interpreted in the standard way, that these pollutants are actually beneficial for health. We do not claim this, but we conclude that the perceived statistical relationship between air pollution and health is not robust

    Indirect Directness

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    In “Teleological Dispositions,” Nick Kroll appeals to teleology to account for the way that dispositions seem to be directed toward their merely possible manifestations. He argues that his teleological account of dispositions (TAD) does a better job of making sense of this directedness than rival approaches that appeal to conditional statements or physical intentionality. In this short critique, I argue that, without satisfactory clarification of a number of issues, TAD does not adequately account for the directedness of dispositions. I focus on two aspects of TAD: the Activation Principle, and the proposed necessary and sufficient conditions for being a dispositional property

    Average Household Size and the Eradication of Malaria

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    Efforts to eradicate malaria during the 20th century succeeded in some parts of the world but failed in others. Malaria also disappeared spontaneously in several countries for reasons that remain an enigma. The connection between malaria and poverty has long been noted. Here we focus on a specific aspect: household size, which has hitherto received little attention. We find strong evidence that when average household size drops below four persons, the probability of malaria eradication jumps dramatically and its incidence in the population drops significantly. This effect is independent of all commonly-studied explanatory variables and was globally valid across all climate zones irrespective of counter measures, vector species, or Plasmodium species. We propose an explanation based on the dispersal mechanism of the parasite. Malaria is transmitted at night by mosquito bite. The mosquito typically spreads the Plasmodium only locally over short distances to new human victims. To survive, the Plasmodium depends on infected humans making social contacts over longer distances. When household size decreases sufficiently, these contacts cross a threshold value that changes the balance between extinctions and replacements and the Plasmodium disappears on its own. We test this interpretation by contrasting our malaria model with dengue fever, which is also poverty-related and mosquito-borne but transmitted differently, namely through daytime exposure. Household size is uncorrelated with dengue incidence, whereas an indicator of outdoor work that is insignificant in the malaria model is highly significant for dengue. We conclude that poverty-induced malaria infection risks are likely to persist, but a focus on reducing effective household size can be a feasible and promising means of its eradication.Malaria;dengue fever, household size, DDT

    Social media and GIScience: Collection, analysis, and visualization of user-generated spatial data

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    Over the last decade, social media platforms have eclipsed the height of popular culture and communication technology, which, in combination with widespread access to GIS-enabled hardware (i.e. mobile phones), has resulted in the continuous creation of massive amounts of user-generated spatial data. This thesis explores how social media data have been utilized in GIS research and provides a commentary on the impacts of this next iteration of technological change with respect to GIScience. First, the roots of GIS technology are traced to set the stage for the examination of social media as a technological catalyst for change in GIScience. Next, a scoping review is conducted to gather and synthesize a summary of methods used to collect, analyze, and visualize this data. Finally, a case study exploring the spatio-temporality of crowdfunding behaviours in Canada during the COVID-19 pandemic is presented to demonstrate the utility of social media data in spatial research

    Rosenberg on Causation

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    This paper is an explication and critique of a new theory of causation found in part II of Gregg Rosenberg\u27s A Place for Consciousness. According to Rosenberg\u27s Theory of Causal significance, causation constrains indeterminate possibilities, and according to his Carrier Theory, physical properties are dispositions which have phenomenal properties as their causal bases. This author finds Rosenberg\u27s metaphysics excessively speculative, with disappointing implications for the place of consciousness in the natural world

    Manifestations as Effects

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    According to a standard characterization of dispositions, when a disposition is activated by a stimulus, a manifestation of that disposition typically occurs. For example, when flammable gasoline encounters a spark in an oxygen-rich environment, the manifestation of flammability—combustion—occurs. In the dispositions/powers literature, it is common to assume that a manifestation is an effect of a disposition being activated. (I use “disposition” and “power” interchangeably). I address two questions in this chapter: Could all manifestations be effects that involve things acquiring only dispositional properties? And, is thinking of manifestations as contributions to effects preferable to thinking of them as effects? I defend negative responses to both questions. If all properties are dispositional, as the pandispositionalists claim, then any time the activation of a disposition results is something acquiring a new property, it results in something acquiring another disposition. Some worry that a vicious regress ensues (Swinburne, 1980; Bird, 2007a, 2007b: 132-46). While I believe that regress arguments can be addressed, my worry is that, on the pandispositionalist view, manifestations become unobservable. Thinking of manifestations as effects is problematic in cases where what actually occurs is not the kind of effect that the power is a power for, but rather a complex interaction of various powers. Because of this, some prefer to think of manifestations as contributions to effects (Molnar, 2003: 194-8; Mumford, 2009). I argue against this proposal on the ground that it introduces mysterious new entities into our ontology. In the end, the most plausible view is that a single kind of power can have different kinds of effects, some of which involve the instantiation of non-dispositional properties. I proceed as follows. In the first section of this chapter, I show that the philosophical concept of a manifestation is the concept of an effect. In the second section, I argue against the claim that all manifestations involve instantiations of only dispositional properties. In the third section, I argue against the view that manifestations are contributions rather than effects

    Drought, Farmers, and Mental Health

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