Simulation analysis of energy production in the B. C. pulp and paper industry

ABSTRACT This paper describes a dynamic simulation model of energy production and use by pulp and paper mills. The model can be used to assess the costs and benefits of the use of different proportions of wood waste (referred to as 'hog fuel') and fossil fuels to generate process steam and electricity, with the costs and benefits measured from several points of view, principally those of the mill management and of the economy as a whole. Using either point of view, the model has been fitted to the eighteen major pulp and paper mills in British Columbia, and used to assess the consequences of the size and nature of optimal hog fuel projects. Some results are reported in this paper and references are given to other papers containing more complete results of various aspects of the research project. INTRODUCTION Whenever there are big changes in technology or relative prices, many of the standard rules of thumb for optimal choices fall apart, and many new alternatives have to be considered in a systematic way. This offers great scope for the design and use of simulation models that capture the key elements of an industrial process and expose the key alternatives for This paper was presented to the conference on Simulation Modelling and Decision in Energy Systems, held in Montreal in June, 1978 and sponsored by the International Association of Science and Technology for Development. It represents early results of work also reported in [1], [2], [3] and [4]. While Helliwell is a continuing member of U.B.C.'s Department of Economics, Cox is currently at M.I.T.'s Energy Laboratory Cambridge, Mass

Recovery from acidification of lochs in Galloway, south-west Scotland, UK: 1979-1998

International audienceThe Galloway region of south-west Scotland has historically been subject to long-term deposition of acidic precipitation which has resulted in acidification of soils and surface waters and subsequent damage to aquatic ecology. Since the end of the 1970s, however, acidic deposition has decreased substantially. The general pattern is for a rapid decline in non-marine sulphate in rainwater over the period 1978-1988 followed by stable concentrations to the mid-1990s. Concentrations of nitrate and ammonium in deposition have remained constant between 1980 and 1998. Seven water quality surveys of 48 lochs in the Galloway region have been conducted between 1979 and 1998. During the first 10 years, from 1979, there was a major decline in regional sulphate concentrations in the lochs, which was expected to have produced a decline in base cations and an increase in the acid neutralising capacity. But sea-salt levels (as indicated by chloride concentrations) were approximately 25% higher in 1988 than in 1979 and thus short-term acidification due to sea-salts offset much of the long-term recovery trend expected in the lochs. During the next 10 years, however, the chloride concentrations returned to 1979 levels and the lochs showed large increases in acid neutralising capacity despite little change in sulphate concentrations. From the observed decline in sulphate deposition and concentrations of sulphate in the lochs, it appears that approximately 75% of the possible improvement in acid neutralising capacity has already occurred over the 20-year period (1979-1998). The role of acid deposition as a driving factor for change in water chemistry in the Galloway lochs is confounded by concurrent changes in other driving variables, most notably, factors related to episodic and year-to-year variations in climate. In addition to inputs of sea-salts, climate probably also influences other chemical signals such as peaks in regional nitrate concentrations and the sharp increase in dissolved organic carbon during the 1990s. Keywords: acidification, recovery, Galloway, sulphur, nitroge

Neighbors' income, public goods, and well‐being

How does neighbors' income affect individual well‐being? Our analysis is based on rich U.S. local data from the Behavioral Risk Factor Surveillance System, which contains information on where respondents live and their self‐reported well‐being. We find that the effect of neighbors' income on individuals' self‐reported well‐being varies with the size of the neighborhood included. In smaller areas such as ZIP codes, we find a positive relationship between median income and individuals' life satisfaction, whereas it is the opposite at the county, MSA, and state levels. We provide evidence that local public goods and local area characteristics such as unemployment, criminality, and poverty rates drive the association between satisfaction and neighbors' income at the ZIP code level. The neighbors' income effects are mainly concentrated among poorer individuals and are as large as one quarter of the effect of own income on self‐reported well‐being

Performance of composite measures used in a trial of etanercept and methotrexate as monotherapy or in combination in psoriatic arthritis

Objectives: To examine which composite measures are most sensitive to change when measuring psoriatic arthritis (PsA) disease activity, analyses compared the responsiveness of composite measures used in a 48-week randomized, controlled trial of MTX and etanercept in patients with PsA. Methods: The trial randomised 851 patients to receive weekly: MTX (20 mg/week), etanercept (50 mg/week) or MTX plus etanercept. Dichotomous composite measures examined included ACR 20/50/70 responses, minimal disease activity (MDA) and very low disease activity (VLDA). Continuous composite measures examined included Disease Activity Score (28 joints) using CRP (DAS28-CRP), Clinical Disease Activity Index (CDAI), Simplified Disease Activity Index (SDAI), Disease Activity for Psoriatic Arthritis (DAPSA) and Psoriatic Arthritis Disease Activity Score (PASDAS). Results: At week 24, etanercept-treated groups were significantly more effective than MTX monotherapy to achieve ACR 20 (primary end point) and MDA (key secondary end point). When examining score changes from baseline at week 24 across the five continuous composite measures, PASDAS demonstrated relatively greater changes in the etanercept-treated groups compared with MTX monotherapy and had the largest effect size and standardized response. Joint count changes drove overall score changes at week 24 from baseline in all the continuous composite measures except for PASDAS, which was driven by the Physician and Patient Global Assessments. Conclusion: PASDAS was the most sensitive continuous composite measure examined with results that mirrored the protocol-defined primary and key secondary outcomes. Composite measures with multiple domains, such as PASDAS, may better quantify change in PsA disease burden. Trail registration: https://ClinicalTrials.gov, number NCT02376790

Legal Status and the Criminal Activity of Immigrants

We exploit exogenous variation in legal status following the January 2007 European Union enlargement to estimate its effect on immigrant crime. We difference out unobserved time-varying factors by (i) comparing recidivism rates of immigrants from the “new” and “candidate” member countries; and (ii) using arrest data on for eign detainees released upon a mass clemency that occurred in Italy in August 2006. The timing of the two events allows us to setup a difference-in-differences strategy. Legal status leads to a 50 percent reduction in recidivism, and explains one-half to two-thirds of the observed differences in crime rates between legal and illegal immigrants

Quantum singularity of Levi-Civita spacetimes

Quantum singularities in general relativistic spacetimes are determined by the behavior of quantum test particles. A static spacetime is quantum mechanically singular if the spatial portion of the wave operator is not essentially self-adjoint. Here Weyl's limit point-limit circle criterion is used to determine whether a wave operator is essentially self-adjoint. This test is then applied to scalar wave packets in Levi-Civita spacetimes to help elucidate the physical properties of the spacetimes in terms of their metric parameters

The World-Trade Web: Topological Properties, Dynamics, and Evolution

This paper studies the statistical properties of the web of import-export relationships among world countries using a weighted-network approach. We analyze how the distributions of the most important network statistics measuring connectivity, assortativity, clustering and centrality have co-evolved over time. We show that all node-statistic distributions and their correlation structure have remained surprisingly stable in the last 20 years -- and are likely to do so in the future. Conversely, the distribution of (positive) link weights is slowly moving from a log-normal density towards a power law. We also characterize the autoregressive properties of network-statistics dynamics. We find that network-statistics growth rates are well-proxied by fat-tailed densities like the Laplace or the asymmetric exponential-power. Finally, we find that all our results are reasonably robust to a few alternative, economically-meaningful, weighting schemes.Comment: 44 pages, 39 eps figure

Happiness and life satisfaction in Rwanda

This study investigated predictors of happiness and life satisfaction in Rwanda. Data from the World Values Survey and gathered from 3 030 Rwandese (age ranging 16 to 90 years, mean age = 34.2, SD = 12.7; females = 50.5%) were pooled for the analysis. For the comparison, international World Values Survey data were utilised. A fixed effects multilevel regression model was used to predict happiness and life satisfaction from gender, health, socio-economic, and some subjective measures. Males had greater self-rated happiness and life satisfaction scores than females. State of health and sense of freedom of choice predicted both happiness and life satisfaction. Valuing of friends, weekly religious attendance, and national pride positively predicted happiness, whereas household’s financial satisfaction, full-time employment, high-income group, being a student, and sense of trust predicted life satisfaction. This study suggests that health status, household’s financial satisfaction and emancipative values could maximise subjective well-being in Rwanda

Particle Creation If a Cosmic String Snaps

We calculate the Bogolubov coefficients for a metric which describes the snapping of a cosmic string. If we insist on a matching condition for all times {\it and} a particle interpretation, we find no particle creation.Comment: 10 pages, MRC.PH.17/9

Regularity of Cauchy horizons in S2xS1 Gowdy spacetimes

We study general S2xS1 Gowdy models with a regular past Cauchy horizon and prove that a second (future) Cauchy horizon exists, provided that a particular conserved quantity $J$ is not zero. We derive an explicit expression for the metric form on the future Cauchy horizon in terms of the initial data on the past horizon and conclude the universal relation A\p A\f=(8\pi J)^2 where A\p and A\f are the areas of past and future Cauchy horizon respectively.Comment: 17 pages, 1 figur