Development of a Fast and Detailed Model of Urban-Scale Chemical and Physical Processing

Abstract and PDF report are also available on the MIT Joint Program on the Science and Policy of Global Change website (http://globalchange.mit.edu/).A reduced form metamodel has been produced to simulate the effects of physical, chemical, and meteorological processing of highly reactive trace species in hypothetical urban areas, which is capable of efficiently simulating the urban concentration, surface deposition, and net mass flux of these species. A polynomial chaos expansion and the probabilistic collocation method have been used for the metamodel, and its coefficients were fit so as to be applicable under a broad range of present-day and future conditions. The inputs upon which this metamodel have been formed are based on a combination of physical properties (average temperature, diurnal temperature range, date, and latitude), anthropogenic properties (patterns and amounts of emissions), and the surrounding environment (background concentrations of certain species). Probability Distribution Functions (PDFs) of the inputs were used to run a detailed parent chemical and physical model, the Comprehensive Air Quality Model with Extensions (CAMx), thousands of times. Outputs from these runs were used in turn to both determine the coefficients of and test the precision of the metamodel, as compared with the detailed parent model. The deviations between the metamodel and the parent mode for many important species (O3, CO, NOx, and BC) were found to have a weighted RMS error less than 10% in all cases, with many of the specific cases having a weighted RMS error less than 1%. Some of the other important species (VOCs, PAN, OC, and sulfate aerosol) usually have their weighted RMS error less than 10% as well, except for a small number of cases. These cases, in which the highly non-linear nature of the processing is too large for the third order metamodel to give an accurate fit, are explained in terms of the complexity and non-linearity of the physical, chemical, and meteorological processing. In addition, for those species in which good fits have not been obtained, the program has been designed in such a way that values which are not physically realistic are flagged. Sensitivity tests have been performed, to observe the response of the 16 metamodels (4 different meteorologies and 4 different urban types) to a broad set of potential inputs. These results were compared with observations of ozone, CO, formaldehyde, BC, and PM10 from a few well observed urban areas, and in most of the cases, the output distributions were found to be within ranges of the observations. Overall, a set of efficient and robust metamodels have been generated which are capable of simulating the effects of various physical, chemical, and meteorological processing, and capable of determining the urban concentrations, mole fractions, and fluxes of species, important to human health and the climate.Federal Agencies and industries that sponsor the MIT Joint Program on the Science and Policy of Global Change

The Same Side of Two Coins: The Peculiar Phenomenon of Bet-Hedging in Campaign Finance

The paper addresses the propensity of large donors to give to competing candidates or competing party organizations during the same election cycle – for example, giving money to both Bush and Kerry during the 2004 presidential race – a practice here termed \u27bet-hedging.\u27 Bet-hedging is analyzed in strategic and game-theoretic terms. The paper explores the prevalence of bet-hedging, the possible motivations behind the practice, and the informational concerns surrounding it. The paper argues that bet-hedging, out of all donation practices, carries with it a uniquely strong implication of ex post favor-seeking: if a donor prefers one side over the other, by bet-hedging it is at least partially cancelling out its own contribution. If the donor has no preference, there is no rational reason to give its money to either side unless it seeks some kind of recognition, in the form of increased access or influence or in the avoidance of retaliation for not giving, by the eventual victor. The paper thus contends that bet-hedging can (constitutionally) and, though it is a tougher question, should (normatively) be regulated under the Buckley v. Valeo and McConnell v. FEC frameworks

Exploring the Structural Conditions Shaping Business-to-Consumer Electronic Commerce

This study investigated fifteen structural factors influencing B2C e-commerce penetration across country contexts. Data collected from secondary sources on a sample of 20 countries showed that e-commerce penetration depends on a country’s network readiness, institutional structures such as ICT laws, supply side labour skills, credit card penetration, per capita GDP and proportion of citizens online. Factors related to a country’s transportation infrastructure, its capacity for technological achievement and its degree of economic freedom are also of significance. The index of structural factors collectively accounts for approximately 76% of the observed variance in e-commerce penetration measured as the ratio of online shoppers to total internet users, and 80% of the observed variance in e-commerce penetration measured as share of total retail sales. The index provides a basis for ongoing analysis of e-commerce and its potential for growth. Results also have important policy implications

The Japanese Product Liability Law: Sending A Pro-Consumer Tsunami Through Japan\u27s Corporate and Judicial Worlds

This note argues that Japan’s former product liability system deprived consumers of adequate protection against product defects. This note also argues that Japan’s changing economic and political conditions necessitated the introduction of strict liability. Part I examines the development of the Japanese legal system, traces the history of product liability in Japan, and discusses the structural and cultural barriers to pursuing product liability claims. Part I also explains the product liability legal theories in existence before the PL Law and discusses the twenty-year process in which Japan debated the prospects of passing this legislation. Part I concludes by discussing factors leading to the PL Law\u27s enactment. Part II discusses the PL Law\u27s provisions and examines the impact of the law on corporate Japan, the judiciary and government, and on Japanese consumers. Part III argues that Japan needed the PL Law to bolster the position of Japanese consumers against manufacturers and enable the Japanese government to facilitate deregulation by reducing its product safety standards. Part III also argues that the PL Law is changing Japanese society by promoting a pro-consumer attitude in Japan\u27s legal and corporate spheres. This Note concludes that the PL Law is a key first step to creating a more equitable product liability recovery system and making manufacturers more accountable to the Japanese public

Cognitive, Affective and Behavioural Responses to an ERP Implementation: A Dual Perspective of Technology Acceptance and Organisational Change

Past studies have drawn on the technology acceptance literature in an attempt to predict users’ behavioural intentions to use a new ERP system. However, few researchers have considered the connections between technology acceptance and organisational change research; and very little ERP research has focused on explanations of user readiness, openness to change and resistance intentions from an organizational change perspective. This paper proposes a model that integrates the perspectives of the organisational change and technology acceptance literatures to define the cognitive, affective, individual and workplace related factors that underpin various behavioural intentions of users during an ERP implementation. The effects of the change management process on cognitions, affects and behavioural intentions are also explored. The context for the study is a South African university undergoing an ERP re-implementation

THE HUNT FOR MITOCHONDRIALLY LOCALIZED CYTOMEGALOVIRUS PROTEINS

Mitochondria perform multiple essential roles in mammalian cells, including the regulation of apoptosis, energy production, and mediation of antiviral responses. Thus, modulating mitochondrial activity is an important mechanism for virus survival in host cells. While the Human Cytomegalovirus (CMV) protein viral mitochondrion-localized inhibitor of apoptosis (vMIA) acts to inhibit apoptosis, the viral mediators of other effects on mitochondria during infection are unknown. We hypothesize that CMV codes for additional mitochondrially localized proteins whose functions may contribute to the modulation of mitochondrial activities. We initially conducted an in si/ico screen to identify CMV proteins that contain a putative mitochondrial localization sequence (MLS). Two candidate proteins, UL19 and UL148, were found to localize to mitochondria through immunofluorescence staining analyses. To gain insight in the potential functions of UL19, a yeast two hybrid screen of a human leukocyte cDNA library was performed to identify the binding partners of each protein. Results suggest that UL19 may interact with the gamma interferon inducible lysosomal thiol reductase enzyme

Trust and Risk in Consumer Acceptance of e-Services: A Meta-Analysis and a Test of Competing Models

Consumer perceptions of risk and their trust beliefs are considered amongst the most important psychological states influencing online behavior. Despite the number of empirical studies that have explored the effects of trust and risk perceptions on consumer acceptance of e-services, the field remains fragmented and the posited research models are contradictory. To address this problem, we examined how trust and risk influence consumer acceptance of e-service through a meta-analysis of 52 studies followed by tests of competing causal models. The findings confirm that trust and risk are important to e-service acceptance but trust has a stronger effect size. We found that certain effect sizes were moderated by such factors as the consumer population under study, the type of e-service, and the object of trust under consideration. The data best supports the causal logic that positions trust as antecedent to risk perceptions. Risk partially mediates the effects of trust on acceptance