The Welfare Cost of Argentine Risk

In this paper we do a couple of things: discussing a way to measure the welfare cost of country risk, and measuring it for Argentina in the period 1875-2006. There are two conclusions: a) the welfare cost of Argentine risk has been huge: for example, in the period 1976-2006 it was around 20% of GDP, several times larger than the welfare cost of any conventional distortion; b) this cost would be wholly paid by labor. These fascinating results deserve further investigation

Direct Interaction of Endogenous Kv Channels with Syntaxin Enhances Exocytosis by Neuroendocrine Cells

K+ efflux through voltage-gated K+ (Kv) channels can attenuate the release of neurotransmitters, neuropeptides and hormones by hyperpolarizing the membrane potential and attenuating Ca2+ influx. Notably, direct interaction between Kv2.1 channels overexpressed in PC12 cells and syntaxin has recently been shown to facilitate dense core vesicle (DCV)-mediated release. Here, we focus on endogenous Kv2.1 channels and show that disruption of their interaction with native syntaxin after ATP-dependent priming of the vesicles by Kv2.1 syntaxin–binding peptides inhibits Ca2+ -triggered exocytosis of DCVs from cracked PC12 cells in a specific and dose-dependent manner. The inhibition cannot simply be explained by the impairment of the interaction of syntaxin with its SNARE cognates. Thus, direct association between endogenous Kv2.1 and syntaxin enhances exocytosis and in combination with the Kv2.1 inhibitory effect to hyperpolarize the membrane potential, could contribute to the known activity dependence of DCV release in neuroendocrine cells and in dendrites where Kv2.1 commonly expresses and influences release

Presynaptic External Calcium Signaling Involves the Calcium-Sensing Receptor in Neocortical Nerve Terminals

Nerve terminal invasion by an axonal spike activates voltage-gated channels, triggering calcium entry, vesicle fusion, and release of neurotransmitter. Ion channels activated at the terminal shape the presynaptic spike and so regulate the magnitude and duration of calcium entry. Consequently characterization of the functional properties of ion channels at nerve terminals is crucial to understand the regulation of transmitter release. Direct recordings from small neocortical nerve terminals have revealed that external [Ca(2+)] ([Ca(2+)](o)) indirectly regulates a non-selective cation channel (NSCC) in neocortical nerve terminals via an unknown [Ca(2+)](o) sensor. Here, we identify the first component in a presynaptic calcium signaling pathway.By combining genetic and pharmacological approaches with direct patch-clamp recordings from small acutely isolated neocortical nerve terminals we identify the extracellular calcium sensor. Our results show that the calcium-sensing receptor (CaSR), a previously identified G-protein coupled receptor that is the mainstay in serum calcium homeostasis, is the extracellular calcium sensor in these acutely dissociated nerve terminals. The NSCC currents from reduced function mutant CaSR mice were less sensitive to changes in [Ca(2+)](o) than wild-type. Calindol, an allosteric CaSR agonist, reduced NSCC currents in direct terminal recordings in a dose-dependent and reversible manner. In contrast, glutamate and GABA did not affect the NSCC currents.Our experiments identify CaSR as the first component in the [Ca(2+)](o) sensor-NSCC signaling pathway in neocortical terminals. Decreases in [Ca(2+)](o) will depress synaptic transmission because of the exquisite sensitivity of transmitter release to [Ca(2+)](o) following its entry via voltage-activated Ca(2+) channels. CaSR may detects such falls in [Ca(2+)](o) and increase action potential duration by increasing NSCC activity, thereby attenuating the impact of decreases in [Ca(2+)](o) on release probability. CaSR is positioned to detect the dynamic changes of [Ca(2+)](o) and provide presynaptic feedback that will alter brain excitability

An econometric model of employment growth in US metropolitan areas

This paper reports on tests of hypotheses about the determinants of employment growth in US metropolitan areas. All urban employment covered by Social Security is included; the hypotheses are tested for each of forty groups of four-digit SIC industries. The units of observation are 284 areas, including all SMSAs, as of 1970, plus some smaller places. The period is 1965 - 1970. The two main findings are: First, ease of attracting labor is not shown to have an important influence on local employment growth. Second, access to markets is the most important factor, followed by localization economies, and -- for some industrial groups -- low wage rates and access to inputs; urbanization economies (measured by city size) are a negative factor for some groups. The research is part of a larger study of the determinants of migration and employment growth.

Field test of six-phase soil heating at the Savannah River Site

Six-Phase Soil Heating (SPSH) was demonstrated as a viable technology for heating low permeability soils containing volatile organic contaminants as part of the Volatile Organic Compounds in Non-Arid Soils Integrated Demonstration (VOC Non-Arid ID) at the Savannah River Site. The soil at the integrated demonstration site is contaminated with perchloroethylene (PCE) and trichloroethylene (TCE); the highest soil contamination occurs in clay rich zones that are ineffectively treated by conventional soil vapor extraction due to the very low permeability of the clay. The SPSH demonstration sought to heat the clay zone and enhance the performance of conventional soil vapor extraction. Thermocouples at 30 locations quantified the areal and vertical heating within the treated zone. Results show successful heating of the targeted clay zone that contained the higher levels of soil contamination. The clay-zone temperatures increased to 1,000 C after 8 days of heating and were maintained near 1,000 C for 17 days. Electrical heating removed 17,000 gal of water from the soil as steam, with peak removal rate of 1,500 gpd of condensed steam

Field test of Six-Phase Soil Heating and evaluation of engineering design code

A field test was conducted to evaluate the performance of Six-Phase Soil Heating to enhance the removal of contaminants. The purpose of the test was to determine the scale-up characteristics of the Six-Phase Soil Heating technology and to evaluate a computer process simulator developed for the technology. The test heated a 20-ft diameter cylinder of uncontaminated soil to a 10-ft depth. Six-phase ac power was applied at a rate of 30--35 kW using a power system built from surplus electrical components. The test ran unattended, using a computer-based system to record data, alert staff of any excursions in operating conditions via telephone, and provide automatic shut-off of power depending on the type of excursion. The test data included in situ soil temperatures, voltage profiles, and moisture profiles (using a neutron-probetechnique). After 50 days of heating, soil in the center of the array at the 6-ft depth reached 80{degrees}C. Soil temperatures between the two electrodes at this depth reached approximately 75{degrees}C. Data from this test were compared with those predicted by a computer process simulator. The computer process simulator is a modified version of the TOUGH2 code, a thermal porous media code that can be used to determine the movement of air and moisture in soils. The code was modified to include electrical resistive heating and configured such that an application could be run quickly on a workstation (approximately 5 min for 1 day of field operation). Temperature and soil resistance data predicted from the process simulations matched actual data fairly closely. A series of parametric studies was performed to assess the affect of simulation assumptions on predicted parameters

Field test of Six-Phase Soil Heating and evaluation of engineering design code

A field test was conducted to evaluate the performance of Six-Phase Soil Heating to enhance the removal of contaminants. The purpose of the test was to determine the scale-up characteristics of the Six-Phase Soil Heating technology and to evaluate a computer process simulator developed for the technology. The test heated a 20-ft diameter cylinder of uncontaminated soil to a 10-ft depth. Six-phase ac power was applied at a rate of 30--35 kW using a power system built from surplus electrical components. The test ran unattended, using a computer-based system to record data, alert staff of any excursions in operating conditions via telephone, and provide automatic shut-off of power depending on the type of excursion. The test data included in situ soil temperatures, voltage profiles, and moisture profiles (using a neutron-probetechnique). After 50 days of heating, soil in the center of the array at the 6-ft depth reached 80[degrees]C. Soil temperatures between the two electrodes at this depth reached approximately 75[degrees]C. Data from this test were compared with those predicted by a computer process simulator. The computer process simulator is a modified version of the TOUGH2 code, a thermal porous media code that can be used to determine the movement of air and moisture in soils. The code was modified to include electrical resistive heating and configured such that an application could be run quickly on a workstation (approximately 5 min for 1 day of field operation). Temperature and soil resistance data predicted from the process simulations matched actual data fairly closely. A series of parametric studies was performed to assess the affect of simulation assumptions on predicted parameters