Regime switching in stochastic models of commodity prices: An application to an optimal tree harvesting problem

This paper investigates a regime switching model of stochastic lumber prices in the context of an optimal tree harvesting problem. Using lumber derivatives prices, two lumber price models are calibrated: a regime switching model and a single regime model. In the regime switching model, the lumber price can be in one of two regimes in which different mean reverting price processes prevail. An optimal tree harvesting problem is specified in terms of a linear complementarity problem which is solved using a fully implicit finite difference, fully-coupled, numerical approach. The land value and critical harvesting prices are found to be significantly different depending on which price model is used. The regime switching model shows promise as a parsimonious model of timber prices that can be incorporated into forestry investment problems.optimal tree harvesting, regime switching, calibration, lumber derivatives prices, fully implicit finite difference approach

The Impact of Stochastic Convenience Yield on Long-term Forestry Investment Decisions

This paper investigates whether convenience yield is an important factor in determining optimal decisions for a forestry investment. The Kalman filter method is used to estimate three different models of lumber prices: a mean reverting model, a simple geometric Brownian motion and the two-factor price model due to Schwartz (1997). In the latter model there are two correlated stochastic factors: spot price and convenience yield. The two-factor model is shown to provide a reasonable fit of the term structure of lumber futures prices. The impact of convenience yield on a forestry investment decision is examined using the Schwartz (1997) long-term model which transforms the two-factor price model into a single factor model with a composite price. Using the long-term model an optimal harvesting problem is analyzed, which requires the numerical solution of an impulse control problem formulated as a Hamilton-Jacobi-Bellman Variational Inequality. We compare the results for the long-term model to those from single-factor mean reverting and geometric Brownian motion models. The inclusion of convenience yield through the long-term model is found to have a significant impact on land value and optimal harvesting decisions.

Crossing the ‘Uncanny Valley’: Adaptation to Cartoon Faces Can Influence Perception of Human Faces

In this study we assessed whether there is a single face space common to both human and cartoon faces by testing whether adaptation to cartoon faces can affect perception of human faces. Participants were shown Japanese animation cartoon videos containing faces with abnormally large eyes. The use of animated videos eliminated the possibility of position-dependent retinotopic adaptation (because the faces appear at many different locations) and more closely simulated naturalistic exposure. Adaptation to cartoon faces with large eyes significantly shifted preferences for human faces toward larger eyes, consistent with a common, non-retinotopic representation for both cartoon and human faces. This supports the possibility that there are representations that are specific to faces yet common to all kinds of faces

Better Ballots

Literacy tests to gain access to the polls were banned in the United States in 1965 with the passage of the Voting Rights Act.99 But in November 2008, eight years after an election debacle of historic proportions, millions of voters across the United States will face a literacy test of a different sort after they've stepped into the voting booth. Their intended choices may be recorded only if they can understand instructions written at a high reading level, often using legal and election terminology. And they will only be counted if they successfully navigate ballot designs that are needlessly complicated, where candidates for the same offi ce may be listed on multiple columns or pages, or different contests are inconsistently formatted. As we have tried to demonstrate in this report, ballot design and instructions can have a huge impact on election results. We sampled some of the more "high profi le" ballot design disasters over the last several years; this is not a comprehensive analysis of the cost of poor ballot design on elections and votes counted. But, the examples illustrate how dramatically poor ballot design can affect vote totals -- particularly when a number of design fl aws appear on the same ballot. Not surprisingly, when these mistakes affected many ballots (by appearing on a signifi cant percentage of the ballots in large counties like Los Angeles or Palm Beach, or on most of the ballots in a particular state), tens of thousands -- and sometimes hundreds of thousands -- of votes in a single federal or statewide race have been lost. This does not even include the voters who may have been so confused by a ballot design that they cast their ballot for a candidate for whom they did not intend to vote (for obvious reasons, it is far more diffi cult to determine this than to know when a voter failed to successfully cast a vote at all). Better ballot design will make it far more likely that the preferred candidates of all voters will be declared winners of their contests. Palm Beach County 2000 should have been a wake-up call to legislators, election offi cials, and watchdog groups that ensuring good ballot design is a critical election administration issue that needs to be systematically addressed. Unfortunately, for the last eight years, it has continued to be largely ignored. The predictable result has disproportionately affected low-income and elderly voters, and thrown several important elections into turmoil. The good news is that there is still time before November 2008 to ensure that ballot design fl aws do not throw the results of another closely contested race into doubt, as has happened in several federal and state races in the last decade. And unlike changes to equipment (which, there is no question, could make systems more secure, accessible and usable), improving ballot design and instructions is possible for little or no cost, and a relatively small-scale investment of time

Post-Election Audits: Restoring Trust in Elections

With the intention of assisting legislators, election officials and the public to make sense of recent literature on post-election audits and convert it into realistic audit practices, the Brennan Center and the Samuelson Law, Technology and Public Policy Clinic at Boalt Hall School of Law (University of California Berkeley) convened a blue ribbon panel (the "Audit Panel") of statisticians, voting experts, computer scientists and several of the nation's leading election officials. Following a review of the literature and extensive consultation with the Audit Panel, the Brennan Center and the Samuelson Clinic make several practical recommendations for improving post-election audits, regardless of the audit method that a jurisdiction ultimately decides to adopt

Corruption and Integrity

"Ordinary people in the country find themselves unable to do business or other things in the ordinary ways. They are compelled to pay ‘incentives’ to get people to do the things they want. They are told extraordinary things about corruption in the high echelons of business and politics, especially where the two people meet. The thought of people being comfortable with the concept of being corrupt is frightening, especially since the systems – both in public service and on the free market – are actually workable. But more alarming than the corruption level is the acceptance level. More and more Malaysians are living with it as if it were a natural part of life. In the past and today, everyone is giving, everyone is taking, and that is how things move in this country. 1 Corruption has become an issue of national importance.", p. 17

Ion radial diffusion in an electrostatic impulse model for stormtime ring current formation

Guiding-center simulations of stormtime transport of ring-current and radiation-belt ions having first adiabatic invariants mu is approximately greater than 15 MeV/G (E is approximately greater than 165 keV at L is approximately 3) are surprisingly well described (typically within a factor of approximately less than 4) by the quasilinear theory of radial diffusion. This holds even for the case of an individual model storm characterized by substorm-associated impulses in the convection electric field, provided that the actual spectrum of the electric field is incorporated in the quasilinear theory. Correction of the quasilinear diffusion coefficient D(sub LL)(sup ql) for drift-resonance broadening (so as to define D(sub LL)(sup ql)) reduced the typical discrepancy with the diffusion coefficients D(sub LL)(sup sim) deduced from guiding-center simulations of representative-particle trajectories to a factor of approximately 3. The typical discrepancy was reduced to a factor of approximately 1.4 by averaging D(sub LL)(sup sim), D(sub LL)(sup ql), and D(sub LL)(sup rb) over an ensemble of model storms characterized by different (but statistically equivalent) sets of substorm-onset times

Disseminated Nocardia cyriacigeorgia causing pancreatitis in a haploidentical stem cell transplant recipient.

We report the first published case of acute pancreatitis secondary to disseminated nocardiosis in a hematopoietic stem cell transplant (HSCT) recipient on chronic immunosuppression for graft-versus-host disease (GVHD). Nocardiosis in the HSCT population is relatively rare, and has not yet been described in haploidentical HSCT recipients. Our patient is a 28-year-old male with a history of haploidentical HSCT and GVHD of the skin and lung who was admitted to the hospital with acute pancreatitis. The workup for the etiology of his pancreatitis was initially unrevealing. He subsequently developed worsening sepsis and respiratory failure despite broad spectrum antimicrobials. After multiple bronchoscopies and pancreatic fluid sampling, he was found to have disseminated nocardiosis with Nocardia cyriacigeorgia

Teaching a Cataloging/Metadata Course in a Changing World: Experience and Reflection

In this paper, we explore the most essential knowledge and skills to impart in an introductory-level cataloging and metadata course. We use the basic cataloging and metadata class in the University of Hawai‘i at Mānoa Library and Information Science Program as a case study, sharing our experiences, thoughts, and planned future direction in teaching cataloging, classification, metadata, and information organization. We investigate what University of Hawai‘i at Mānoa Library and Information Science (LIS) students expect to learn from the class, as well as how they perceive knowledge of and skills in cataloging and metadata affecting their career paths. We also inquire into topics that the students are interested in exploring related to cataloging and metadata. We examine emerging trends and evaluate which information and skills are most useful for LIS students and new librarians to learn for their library careers. These ideas are built upon our own experiences teaching these topics. This article synthesizes literature review, observation of trends within cataloging and metadata, and surveys taken by students enrolled in the course.