The Effect of Carbon Payments on Deforestation Rates and Carbon Sequestration: Estimates from a Global Forestry and Agricultural Model.

Environmental Economics and Policy,

Majorana zero modes in a quantum Ising chain with longer-ranged interactions

A one-dimensional Ising model in a transverse field can be mapped onto a system of spinless fermions with p-wave superconductivity. In the weak-coupling BCS regime, it exhibits a zero energy Majorana mode at each end of the chain. Here, we consider a variation of the model, which represents a superconductor with longer ranged kinetic energy and pairing amplitudes, as is likely to occur in more realistic systems. It possesses a richer zero temperature phase diagram and has several quantum phase transitions. From an exact solution of the model these phases can be classified according to the number of Majorana zero modes of an open chain: 0, 1, or 2 at each end. The model posseses a multicritical point where phases with 0, 1, and 2 Majorana end modes meet. The number of Majorana modes at each end of the chain is identical to the topological winding number of the Anderson's pseudospin vector that describes the BCS Hamiltonian. The topological classification of the phases requires a unitary time-reversal symmetry to be present. When this symmetry is broken, only the number of Majorana end modes modulo 2 can be used to distinguish two phases. In one of the regimes, the wave functions of the two phase shifted Majorana zero modes decays exponentially in space but but in an oscillatory manner. The wavelength of oscillation is identical to the asymptotic connected spin-spin correlation of the XY-model in a transverse field to which our model is dual.Comment: 11 pages, 8 figures; brief clarifying comments added; few new references; this version is accepted in Phys. Rev.

Endpoints of hepatitis B treatment

The goal of hepatitis B treatment is to prevent the development of cirrhosis, liver failure, and hepatocellular carcinoma. Ideally, clinical studies should demonstrate that hepatitis B therapies can prevent liver-related complications; however, these clinical endpoints evolve over years or decades. Therefore, clinical trials have relied on intermediate endpoints to evaluate the efficacy of treatment and to determine when treatment can be stopped. Intermediate endpoints that have been used include biochemical, histological, virological, and serological endpoints. This review will discuss the validity of these intermediate endpoints as surrogates of clinical endpoints, and the rates at which these intermediate endpoints can be achieved with currently available therapies.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/79271/1/j.1365-2893.2010.01369.x.pd

Application of molecular biomarkers in epidemiology.

The principal conclusions and opportunities that can be drawn from this conference are as follows. The meeting demonstrated the large communication gap that still exists between most epidemiologists and laboratory scientists. This problem could be overcome if epidemiologists worked closely with laboratory scientists at the outset of any project so that a better understanding could be built between them. Epidemiologists need simple, well-characterized, reproducible assays that can be applied to hundreds or thousands of people. Most laboratory scientists have little interest in running large numbers of assays, but wish to continually refine their methods so that they stay on the "cutting edge" of basic research. This problem could be overcome if the new laboratory technology could be transferred to contract laboratories or small companies. Problems of technology transfer therefore need to be addressed. Current and new biomarkers need to be better validated in the field and by studying animal models. More information on the background expression of biomarkers in the general population is needed (i.e. what is the normal range?). Ethical issues, such as the possibility that biomarkers of susceptibility could be used to exclude people from the workplace, need to be addressed

A TWO-STAGE APPROACH FOR ESTIMATING THE EFFECT OF DNA METHYLATION ON DIFFERENTIAL EXPRESSION USING TILING ARRAY TECHNOLOGY

Epigenetics is the study of heritable alterations in gene function without changing the DNA sequence itself. It is known that epigenetic modifications such as DNA methylation and histone modifications are highly correlated with the regulation of gene expression. A twostage analysis is proposed that employs a hidden Markov model and a linear model to evaluate differential expression as related to DNA methylation for the purpose of examining the effects of DNA methylation on gene regulation using tiling array technology. In the first stage, a hidden Markov model (HMM) is employed to estimate the methylation status per tile by utilizing information of neighboring tiles. In the second stage, a linear model is applied to the expression data to identify significantly differentially expressed tiles given the changes in methylation status. The two-stage analysis is applied to Arabidopsis chromosome 4 tiling array data and the results are compared with a traditional ANOVA model which has been employed to identify significantly differentially expressed genes using microarray data

Noise Robust Pitch Tracking by Subband Autocorrelation Classification

Pitch tracking algorithms have a long history in various applications such as speech coding and extracting information, as well as other domains such as bioacoustics and music signal processing. While autocorrelation is a useful technique for detecting periodicity, autocorrelation peaks suffer ambiguity, leading to the classic “octave error” in pitch tracking. Moreover, additive noise can affect autocorrelation in ways that are difficult to model. Instead of explicitly using the most obvious features of autocorrelation, we present a trained classifier-based approach which we call Subband Autocorrelation Classification (SAcC). A multi-layer perceptron classifier is trained on the principal components of the autocorrelations of subbands from an auditory filterbank. Training on bandlimited and noisy speech (processed to simulate a low-quality radio channel) leads to a great increase in performance over state-of-the-art algorithms, according to both the traditional GPE measure, and a proposed novel Pitch Tracking Error which more fully reflects the accuracy of both pitch extraction and voicing detection in a single measure