Bias in U.S. Import Prices and Demand

The purpose of the paper is to measure the potential bias in the U.S. import price index due to the appearance of new product varieties, or new foreign suppliers, and determine the effect of this bias on the estimated income elasticity of import demand. Existing import price indexes are based on a sample of products from importing firms. We argue that if the share of import expenditure on the sampled products is falling over time, this will lead to an upward bias in the measured index. Using a correction based on the falling expenditure share on sampled countries, we find that the income elasticity of aggregate U.S. import demand is reduced from 2.5 to 1.7, or about halfway to unity. Our estimates suggest that the aggregate import price index is upward biased by about one and one-half percentage points annually.

Econometric estimation of Armington import elasticities for a regional CGE model of the Illinois economy

One of the main concerns associated with the development and use of regional CGE models is the determination of key parameter values, particularly substitution and other price elasticities. A common problem is the lack of appropriate regional data for econometric estimation. Consequently, it is important to identify key parameters that are likely to be important in determining quantitative results and then to prioritize these for estimation where appropriate data are available. In this paper, the focus is on the estimation of the regional trade (import) substitution parameters, which tend to be important in analysis for regional economies (given their openness to trade). Here, commodity import elasticities for the Illinois economy are estimated and tested in a single region CGE model of the Illinois economy. In our econometric estimation, we apply a model that takes account of market size and distance in estimating the substitutability between commodities produced in Illinois and other US states

Detection of early age-related macular degeneration using novel functional parameters of the focal cone electroretinogram

The focal cone electroretinogram is a sensitive marker for macular disease, but have we unlocked its full potential? Typically assessment of waveform parameters is subjective and focuses on a small number of locations (e.g. the a-wave). This study evaluated the discriminatory and diagnostic potential of 4 conventional and 15 novel, objectively determined, parameters in patients with early Age-related Macular Degeneration. Focal cone electroretinograms were recorded in 54 participants with early Age-related Macular Degeneration (72.9±8.2 years) and 54 healthy controls (69±7.7 years). Conventional a and b wave amplitudes and implicit times were measured and compared to novel parameters derived from both the 1st and 2nd derivatives and the frequency-domain power spectrum of the electroretinogram.Statistically significant differences between groups were shown for all conventional parameters, the majority of 1st and 2nd derivative parameters and the power spectrum at 25 and 30 Hz. Receiver operating characteristics showed that both conventional and 1st and 2nd derivative implicit times had provided the best diagnostic potential. A regression model showed a small improvement over any individual parameter investigated. The non-conventional parameters enhanced the objective evaluation of the focal electroretinogram, especially when the amplitude was low. Furthermore, the novel parameters described here allow the implicit time of the electroretinogram to be probed at points other than the peaks of the a and b waves. Consequently these novel analysis techniques could prove valuable in future electrophysiological investigation, detection and monitoring of Age-related Macular Degeneration

Novel Expression Patterns of Metabotropic Glutamate Receptor 6 in the Zebrafish Nervous System

The metabotropic glutamate receptor 6 (mGluR6 or GRM6) belongs to the class III of the metabotropic glutamate receptor family. It is the only known mGluR that mediates direct synaptic transmission in the nervous system and is thought to mediate the ON-response in the ON-pathway of the vertebrate retina. Phylogenetic and gene structure analysis indicated that the zebrafish genome harbours two mglur6 paralogs, mglur6a and mglur6b. Besides expression in the inner nuclear layer and distinct regions in the brain, both mglur6 paralogs are expressed in ganglion cells of the retina, an expression pattern which can also be observed in the downstream effector molecules gnaoa and gnaob. This unexpected expression pattern is consistent with immunohistological labeling using a peptide antibody specific for the mGluR6b paralog. These expression patterns contradict the existing view that mGluR6 is solely located on ON-bipolar cells where it functions in signal transmission. Consistent with expression in ON-bipolar cells, we report a decreased b-wave amplitude in the electroretinogram after morpholino-based downregulation of mGluR6b, showing a function in the ON response. Our data suggest more widespread functions of mGluR6 mediated signaling in the central nervous system, possibly including sign reversing synapses in the inner retina

Concentration-Dependent Activity of Hydromethylthionine on Cognitive Decline and Brain Atrophy in Mild to Moderate Alzheimer’s Disease

ACKNOWLEDGMENTS We gratefully acknowledge study investigators and the generosity of study participants. We gratefully acknowledge Professor Gordon Wilcock for critical review and commentary on drafts of the manuscript. Author’s disclosures available online (https://www.j-alz.com/manuscript-disclosures/19-0772r1). SUPPLEMENTARY MATERIAL The supplementary material is available in the electronic version of this article: http://dx.doi.org/10.3233/JAD-190772. Availability of data and materials The datasets and analyses used during the current study are available from the corresponding author on reasonable request.Peer reviewedPublisher PD

A Positive Feedback Synapse from Retinal Horizontal Cells to Cone Photoreceptors

Cone photoreceptors and horizontal cells (HCs) have a reciprocal synapse that underlies lateral inhibition and establishes the antagonistic center-surround organization of the visual system. Cones transmit to HCs through an excitatory synapse and HCs feed back to cones through an inhibitory synapse. Here we report that HCs also transmit to cone terminals a positive feedback signal that elevates intracellular Ca2+ and accelerates neurotransmitter release. Positive and negative feedback are both initiated by AMPA receptors on HCs, but positive feedback appears to be mediated by a change in HC Ca2+, whereas negative feedback is mediated by a change in HC membrane potential. Local uncaging of AMPA receptor agonists suggests that positive feedback is spatially constrained to active HC-cone synapses, whereas the negative feedback signal spreads through HCs to affect release from surrounding cones. By locally offsetting the effects of negative feedback, positive feedback may amplify photoreceptor synaptic release without sacrificing HC-mediated contrast enhancement