Detecting illegal trade practices by analyzing discrepancies in forest products trade statistics : An application to Europe, with a focus on Romania

Discrepancies in bilateral trade statistics for forest products have recently attracted attention as potential indicators of illegal trade practices. For example, if exporters understate quantities to evade export taxes or quotas, then one might expect reported exports to be less than reported imports. Discrepancies in trade statistics can exist for reasons that have nothing to do with illegal activities, however, such as measurement error and shipment lags. Any attempt to infer evidence of illegal activities from statistical discrepancies must control for these other explanations. The author estimates the discrepancies between reported imports and exports for bilateral flows of sawnwood traded by Romania and other European countries. The author also examines whether these discrepancies reflect illegal activities by the traders. The mean discrepancy for sawnwood exported by Romania during 1982-97 was significantly different from zero for coniferous sawnwood but not for nonconiferous sawnwood. Yet the sign of the discrepancy for coniferous sawnwood-reported exports tended to be greater than reported imports-implies that illegal trade activities were more likely occurring in Romania's trading partners than in Romania. An econometric analysis of bilateral trade statistics for Romania and other European countries finds evidence that measurement error, shipment lags, and intentional underreporting all play a role in explaining discrepancies for both types of sawnwood. The econometric model is not sufficiently reliable, however, for estimating the portion that was due solely to illegal activities or determining whether those activities occurred primarily in Romania or in its trading partners. Moreover, given that it is based on observed discrepancies in bilateral trade statistics, it fails to detect illegal trade activities that occur simultaneously in both importing and exporting countries. For these reasons, econometric methods appear unlikely to be of practical use in revealing illegal trade activities in the Romanian forest sector.Environmental Economics&Policies,Economic Theory&Research,Development Economics&Aid Effectiveness,Trade Policy,Agribusiness&Markets,Trade Policy,Economic Theory&Research,TF054105-DONOR FUNDED OPERATION ADMINISTRATION FEE INCOME AND EXPENSE ACCOUNT,Environmental Economics&Policies,Agribusiness&Markets

Dynamics of meromorphic maps with small topological degree III: geometric currents and ergodic theory

We continue our study of the dynamics of mappings with small topological degree on (projective) complex surfaces. Previously, under mild hypotheses, we have constructed an ergodic ``equilibrium'' measure for each such mapping. Here we study the dynamical properties of this measure in detail: we give optimal bounds for its Lyapunov exponents, prove that it has maximal entropy, and show that it has product structure in the natural extension. Under a natural further assumption, we show that saddle points are equidistributed towards this measure. This generalize results that were known in the invertible case and is, to our knowledge, one among not very many instances in which a natural invariant measure for a non-invertible dynamical system is well-understood.Comment: v3. Exposition improved. Final version, to appear in Ann. Scient. de l'EN

Dynamics of meromorphic maps with small topological degree I: from cohomology to currents

We consider the dynamics of a meromorphic map on a compact kahler surface whose topological degree is smaller than its first dynamical degree. The latter quantity is the exponential rate at which its iterates expand the cohomology class of a kahler form. Our goal in this article and its sequels is to carry out a conjectural program for constructing and analyzing a natural measure of maximal entropy for each such map. Here we take the first step, converting information about the linear action of the map on cohomology to invariant currents with special geometric structure. We also give some examples and identify some additional properties of maps on irrational surfaces and of maps whose invariant cohomology classes have vanishing self-intersection.Comment: Final version, to appear in Indiana University Mathematics Journal. Among other changes, discussion of polynomial maps is improve

Promoting better logging practices in tropical forests

The study presented in this paper tests the empirical significance of several common recommendations for promoting better logging practices in tropicalforests: in particular, making concession agreements longer, linking renewal of those agreements to logging practices, and using performance bonds to encourage compliance with logging regulations. It assesses how these recommendations affect both the economics of timber harvesting and the provision of environmental benefits. With regard to the latter it focuses on carbon sequestration and biodiversity. It also examines the effects of timber fees and discount rates on economic and environmental outcomes. The study focuses on two aspects of logger behavior: choice of logging technology and compliance with prescribed minimum diameter cutting limits. The study analyzes loggers'decisions about technology and cutting limits in two scenarios: (i) the repeated harvesting of a given forest stand (virgin forest for the initial harvest, second growth forest for subsequent harvests), which occurs at a time delay of several decades (the cutting cycle); and (ii) the sequential harvesting of an annual series of different forest stands with identical characteristics (all virgin). The former gets at issues of sustainable forest management, while the latter gets at the mining of virgin timber stocks. In this way, the study examines both the long-run and short-run dynamics of logger behavior. The paper is organized as follows. The authors begin by describing the models of forest growth and logger behavior that comprise the simulation model. The description of the forest growth model includes the indicators used to predict the environmental impacts of logging, and the description of the model of logger behavior includes the regulatory instruments analyzed. Next, they present and discuss the simulation results, dealing with repeated harvesting and sequential harvesting in turn. In the final section the report highlights the principal conclusions that can be drawn from these results.Forests and Forestry,Environmental Economics&Policies,Water Conservation,Silviculture,Agribusiness,Environmental Economics&Policies,Agricultural Trade,Agribusiness,Forestry,Silviculture

Opportunity-Rich Schools and Sustainable Communities: Seven Steps to Align High-Quality Education With Innovations in City and Metropolitan Planning and Development

Details challenges and steps for linking quality education and community and economic vitality, including establishing a shared vision and metrics, aligning investments for prosperity, and expanding access via transportation. Lists promising practices

Nature, socioeconomics and adaptation to natural disasters: new evidence from floods

The authors analyze the determinants of fatalities in 2,194 large flood events in 108 countries between 1985 and 2008. Given that socioeconomic factors can affect mortality right in the aftermath of a flood, but also indirectly by influencing flood frequency and magnitude, they distinguish between direct and indirect effects of development on flood mortality. The authors find that income is negatively associated with the frequency of floods and, conditional on their magnitude, the fatalities they cause in developing countries. However, for developed countries they find that increased income is associated with more fatalities, both directly (conditional on flood occurrence and magnitude) and indirectly through an increase in the frequency and magnitude of flood events. Also in contrast to the literature, they find that the effect of governance on flood frequency and fatalities in developing countries is U-shaped, with improvements in governance reducing the numbers of floods and deaths when governance is weaker but raising them when governance is stronger.Hazard Risk Management,Natural Disasters,Governance Indicators,Disaster Management,Flood Control

Modeling cell proliferation in a perfusion tissue engineering bioreactor

In this dissertation we develop a comprehensive model to simulate a tissue engineering experiment. The experiment takes place in a bioreactor in which a cell seeded porous scaffold is placed, and the scaffold experiences a perfused flow of a nutrient-rich culture medium. The goal of the model is to assist experimentalists in evaluation of different parameter scenarios as the time needed to simulate an experiment is significantly less than the time needed for the experiment itself. We provide the full two-dimensional model development, as well as investigation into possible variations of specific model choices, and we demonstrate the robustness and versatility of the model. Simulation results are presented with different initial cell seeding scenarios which increase in complexity with each simulation. We next model the effect of printing a growth factor onto the scaffold in an attempt to direct cell motility and enhance proliferation via a process known as haptotaxis. While a quantitative representation of these phenomena requires more experimental data than are yet available, qualitative agreement with preliminary experimental studies is obtained, and appears promising. The ultimate goal of such modeling is to ascertain initial conditions (growth factor distribution, initial cell seeding, etc.) that will lead to a final desired outcome. A simplified 2D mathematical model for tissue growth within a cyclically-loaded tissue engineering scaffold is then analyzed. Such cyclic loading has the potential to improve yield and functionality of tissue such as bone and cartilage when grown on a scaffold within a perfusion bioreactor. The cyclic compression affects the flow of the perfused nutrient, leading to flow properties that are inherently unsteady, though periodic, on a timescale short compared with that of tissue proliferation. A two-timescale analysis based on these two well-separated timescales is exploited to derive a closed model for the tissue growth on the long timescale. Some sample numerical results are given for the final model, and the comparison with the unloaded case is discussed. Finally, we simulate to hypothetical extensions to the basic model. We first test the hypothesis of a death rate which varies as a function of the local fluid flow and compare the results to the original model. The second test is the introduction of a channel through the center of the porous scaffold thought to aid in nutrient delivery to the cells in the interior of the scaffold. The last two simulations are presented to illustrate the ability that the model has to incorporate many different supplemental experimental situations, whether they have yet been experimentally considered or not

Why do Nigerian manufacturing firms take action on AIDS?

This repository item contains a single issue of the Health and Development Discussion Papers, an informal working paper series that began publishing in 2002 by the Boston University Center for Global Health and Development. It is intended to help the Center and individual authors to disseminate work that is being prepared for journal publication or that is not appropriate for journal publication but might still have value to readers.OBJECTIVE: To identify differences between manufacturing firms in Nigeria that have undertaken HIV/AIDS prevention activities and those that have not as a step toward improving the targeting of HIV policies and interventions. METHODS: A survey of a representative sample of registered manufacturing firms in Nigeria, stratified by location, workforce size, and industrial sector. The survey was administered to managers of 232 firms representing most major industrial areas and sectors in March-April 2001. RESULTS: 45.3 percent of the firms’ managers received information about HIV/AIDS from a source outside the firm in 2000; 7.7 percent knew of an employee who was HIV-positive at the time of the survey; and 13.6 percent knew of an employee who had left the firm and/or died in service due to AIDS. Only 31.7 percent of firms took any action to prevent HIV among employees in 2000, and 23.9 percent had discussed the epidemic as a potential business concern. The best correlates of having taken action on HIV were knowledge of an HIV-positive employee or having lost an employee to AIDS (odds ratio [OR] 6.36, 95% confidence interval [CI]: 2.30, 17.57) and receiving information about the disease from an outside source (OR 7.83, 95% CI: 3.46, 17.69). CONCLUSIONS: Despite a nationwide HIV seroprevalence of 5.8 percent, as of 2001 most Nigerian manufacturing firm managers did not regard HIV/AIDS as a serious problem and had neither taken any action on it nor discussed it as a business issue. Providing managers with accurate, relevant information about the epidemic and practical prevention interventions might strengthen the business response to AIDS in countries like Nigeria