Comparing Tests of Autoregressive Versus Moving Average Errors in Regression Models Using Bahadur's Asymptotic Relative Efficiency,

The purpose of this paper is to use Bahadur's asymptotic relative efficiency measure to compare the performance of various tests of autoregressive (AR) versus moving average (MA) error processes in regression models. Tests to be examined include non-nested procedures of the models against each other, and classical procedures based upon testing both the AR and MA error processes against the more general autoregressive-moving average model.

Volatility Surface and Skewness in Live Cattle Futures Price Distributions with Application to North American BSE Announcements

options markets, live cattle, volatility, pricing density function, Financial Economics, Livestock Production/Industries, Risk and Uncertainty,

LL601 Contamination and Its Impact on U.S. Rice Prices

LL601 is a genetically modified rice variety and unapproved for commercial use. Its presence was found in commercial shipments of U.S. rice in 2006. This article explores its impact on prices and volume marketed for both the United States and Thailand, the major export competitor. The results show a significantly adverse but short duration effect on the U.S. rice market and little to no effect on the Thai rice market.cointegration, error correction model, event study analysis, GM contamination, LibertyLink Rice 601, U.S. rice exports, Agribusiness, Agricultural and Food Policy, Crop Production/Industries, Food Consumption/Nutrition/Food Safety, International Relations/Trade, Research and Development/Tech Change/Emerging Technologies, C10, C32, Q11, A52,

Kinetic Resolution in Asymmetric Epoxidation using Iminium Salt Catalysis

The first reported examples of kinetic resolution in epoxidation reactions using iminium salt catalysis are described, providing up to 99% ee in the epoxidation of racemic cis-chromenes

Simultaneous measurement of mitochondrial calcium and mitochondrial membrane potential in live cells by fluorescent microscopy

Apart from their essential role in generating ATP, mitochondria also act as local calcium (Ca(2+)) buffers to tightly regulate intracellular Ca(2+) concentration. To do this, mitochondria utilize the electrochemical potential across their inner membrane (ΔΨm) to sequester Ca(2+). The influx of Ca(2+) into the mitochondria stimulates three rate-limiting dehydrogenases of the citric acid cycle, increasing electron transfer through the oxidative phosphorylation (OXPHOS) complexes. This stimulation maintains ΔΨm, which is temporarily dissipated as the positive calcium ions cross the mitochondrial inner membrane into the mitochondrial matrix. We describe here a method for simultaneously measuring mitochondria Ca(2+) uptake and ΔΨm in live cells using confocal microscopy. By permeabilizing the cells, mitochondrial Ca(2+) can be measured using the fluorescent Ca(2+) indicator Fluo-4, AM, with measurement of ΔΨm using the fluorescent dye tetramethylrhodamine, methyl ester, perchlorate (TMRM). The benefit of this system is that there is very little spectral overlap between the fluorescent dyes, allowing accurate measurement of mitochondrial Ca(2+) and ΔΨm simultaneously. Using the sequential addition of Ca(2+) aliquots, mitochondrial Ca(2+) uptake can be monitored, and the concentration at which Ca(2+) induces mitochondrial membrane permeability transition and the loss of ΔΨm determined

Bandwidth-controlled Mott transition in κ−(BEDT−TTF)2Cu[N(CN)2]BrxCl1−x\kappa-(BEDT-TTF)_2 Cu [N(CN)_2] Br_x Cl_{1-x} I. Optical studies of localized charge excitations

Infrared reflection measurements of the half-filled two-dimensional organic conductors $\kappa$-(BEDT-TTF)$_2$Cu[N(CN)$_{2}$]Br$_{x}$Cl$_{1-x}$ were performed as a function of temperature ($5 {\rm K}<T<300$ K) and Br-substitution ($x=0$, 40%, 73%, 85%, and 90%) in order to study the metal-insulator transition. We can distinguish absorption processes due to itinerant and localized charge carriers. The broad mid-infrared absorption has two contributions: transitions between the two Hubbard bands and intradimer excitations from the charges localized on the (BEDT-TTF)$_2$ dimer. Since the latter couple to intramolecular vibrations of BEDT-TTF, the analysis of both electronic and vibrational features provides a tool to disentangle these contributions and to follow their temperature and electronic-correlations dependence. Calculations based on the cluster model support our interpretation.Comment: 12 pages, 12 figure

Residual disease and HPV persistence after cryotherapy for cervical intraepithelial neoplasia grade 2/3 in HIV positive women in Kenya

Objective: To assess residual cervical intraepithelial neoplasia (CIN) 2/3 disease and clearance of high-risk (hr) human papillomavirus (HPV) infections at 6 months after cryotherapy among HIV-positive women. Design: Follow-up study. Methods: 79 HIV-positive women received cryotherapy for CIN2/3 in Nairobi, Kenya, and underwent conventional cytology 6 months later. Biopsies were performed on high grade cytological lesions and hrHPV was assessed before (cervical cells and biopsy) and after cryotherapy (cells). Results: At 6 months after cryotherapy CIN2/3 had been eliminated in 61 women (77.2%; 95% Confidence Interval, (CI):66.4–85.9). 18 women (22.8%) had residual CIN2/3, and all these women had hrHPV at baseline. CD4 count and duration of combination antiretroviral therapy (cART) were not associated with residual CIN2/3. CIN3 instead of CIN2 was the only significant risk factor for residual disease (odds ratio, OR vs CIN2 = 4.3; 95% CI: 1.2–15.0) among hrHPV-positive women after adjustment for age and HPV16 infection. Persistence of hrHPV types previously detected in biopsies was found in 77.5% of women and was associated with residual CIN2/3 (OR = 8.1, 95% CI: 0.9–70). The sensitivity, specificity, and negative predictive value of hrHPV test in detecting residual CIN2/3 were 0.94, 0.36, and 0.96 respectively. Conclusions: Nearly one quarter of HIV-positive women had residual CIN2/3 disease at 6 months after cryotherapy, and the majority had persistent hrHPV. CD4 count and cART use were not associated with residual disease or hrHPV persistence. The value of hrHPV testing in the detection of residual CIN2/3 was hampered by a low specificity

Multimodal probes : superresolution and transmission electron microscopy imaging of mitochondria, and oxygen mapping of cells, using small-molecule Ir(III) luminescent complexes

We describe an Ir(III)-based small-molecule, multimodal probe for use in both light and electron microscopy. The direct correlation of data between light- and electron-microscopy-based imaging to investigate cellular processes at the ultrastructure level is a current challenge, requiring both dyes that must be brightly emissive for luminescence imaging and scatter electrons to give contrast for electron microscopy, at a single working concentration suitable for both methods. Here we describe the use of Ir(III) complexes as probes that provide excellent image contrast and quality for both luminescence and electron microscopy imaging, at the same working concentration. Significant contrast enhancement of cellular mitochondria was observed in transmission electron microscopy imaging, with and without the use of typical contrast agents. The specificity for cellular mitochondria was also confirmed with MitoTracker using confocal and 3D-structured illumination microscopy. These phosphorescent dyes are part of a very exclusive group of transition-metal complexes that enable imaging beyond the diffraction limit. Triplet excited-state phosphorescence was also utilized to probe the O2 concentration at the mitochondria in vitro, using lifetime mapping techniques

Searching for stochastic gravitational-wave background with the co-located LIGO interferometers

This paper presents techniques developed by the LIGO Scientific Collaboration to search for the stochastic gravitational-wave background using the co-located pair of LIGO interferometers at Hanford, WA. We use correlations between interferometers and environment monitoring instruments, as well as time-shifts between two interferometers (described here for the first time) to identify correlated noise from non-gravitational sources. We veto particularly noisy frequency bands and assess the level of residual non-gravitational coupling that exists in the surviving data.Comment: Proceedings paper from the 7th Edoardo Amaldi Conference on Gravitational Waves, held in Sydney, Australia from 8-14 July 2007. Accepted to J. Phys.: Conf. Se