A new effective exchange rate index for the dollar and its implications for U.S. merchandise trade

An introduction to a new exchange-rate index to measure the foreign-exchange value of the dollar. The authors develop a model of U.S. merchandise trade, featuring the new index.Foreign exchange rates ; Dollar, American

Structural Considerations for Larger Upper Stage Development

The selection of design configurations and materials for large vehicles such as those proposed for manned missions to Mars in the early 1980\u27s will require the resolving of major technological questions during the next few years. The structure required to contain the large volume of liquid propellants, particularly hydrogen, must be of efficient design so that payload capability can be maximized. In a typical study recently conducted, design criteria were established for a multimodule upper stage. Each stage module consists of a basic shell structure, an insulated, internally mounted LH2 propellant tank, and the thrust engine with its associated support system and hardware. Meteoroid protection is incorporated in the shell structure. The largest potential for structural weight-saving appears to be in the propellant tank design. Aluminum alloys are currently favored as tank material because of successful experience and the high level of technological development. Titanium alloys, however, offer sizeable potential weight savings because of their superior biaxial strength properties at cryogenic temperatures. The biaxial strengths of titanium alloys range from 30% to 70% greater than their uniaxial strength, compared to less than 15% for the aluminum alloys. However, there are certain requisite programs that must be conducted before titanium can be introduced as a qualified structural material for large cryogenic tankage. This study investigated the following areas: texture strengthening of titanium alloys, nondestructive inspection techniques, critical crack size, proof load levels, compatibility with LH;? under long-term storage conditions, stress corrosion, creep, and low-cycle fatigue. Only with positive results in these areas could the materials be used. Efficient means of attachment of structural components to thin-gage tanks were studied, as were manufacturing considerations for the vehicles. These included material size, development of welding methods and equipment, and techniques for handling the large, thin-gage upper stage structural components before, during, and after fabrication

A Quantum-Classical Brackets from p-Mechanics

We provide an answer to the long standing problem of mixing quantum and classical dynamics within a single formalism. The construction is based on p-mechanical derivation (quant-ph/0212101, quant-ph/0304023) of quantum and classical dynamics from the representation theory of the Heisenberg group. To achieve a quantum-classical mixing we take the product of two copies of the Heisenberg group which represent two different Planck's constants. In comparison with earlier guesses our answer contains an extra term of analytical nature, which was not obtained before in purely algebraic setup. Keywords: Moyal brackets, Poisson brackets, commutator, Heisenberg group, orbit method, representation theory, Planck's constant, quantum-classical mixingComment: LaTeX, 7 pages (EPL style), no figures; v2: example of dynamics with two different Planck's constants is added, minor corrections; v3: major revion, a complete example of quantum-classic dynamics is given; v4: few grammatic correction

Renormalized Effective Actions in Radially Symmetric Backgrounds I: Partial Wave Cutoff Method

The computation of the one-loop effective action in a radially symmetric background can be reduced to a sum over partial-wave contributions, each of which is the logarithm of an appropriate one-dimensional radial determinant. While these individual radial determinants can be evaluated simply and efficiently using the Gel'fand-Yaglom method, the sum over all partial-wave contributions diverges. A renormalization procedure is needed to unambiguously define the finite renormalized effective action. Here we use a combination of the Schwinger proper-time method, and a resummed uniform DeWitt expansion. This provides a more elegant technique for extracting the large partial-wave contribution, compared to the higher order radial WKB approach which had been used in previous work. We illustrate the general method with a complete analysis of the scalar one-loop effective action in a class of radially separable SU(2) Yang-Mills background fields. We also show that this method can be applied to the case where the background gauge fields have asymptotic limits appropriate to uniform field strengths, such as for example in the Minkowski solution, which describes an instanton immersed in a constant background. Detailed numerical results will be presented in a sequel.Comment: 35 page

Expression quantitative trait loci are highly sensitive to cellular differentiation state

Blood cell development from multipotent hematopoietic stem cells to specialized blood cells is accompanied by drastic changes in gene expression for which the triggers remain mostly unknown. Genetical genomics is an approach linking natural genetic variation to gene expression variation, thereby allowing the identification of genomic loci containing gene expression modulators (eQTLs). In this paper, we used a genetical genomics approach to analyze gene expression across four developmentally close blood cell types collected from a large number of genetically different but related mouse strains. We found that, while a significant number of eQTLs (365) had a consistent “static” regulatory effect on gene expression, an even larger number were found to be very sensitive to cell stage. As many as 1,283 eQTLs exhibited a “dynamic” behavior across cell types. By looking more closely at these dynamic eQTLs, we show that the sensitivity of eQTLs to cell stage is largely associated with gene expression changes in target genes. These results stress the importance of studying gene expression variation in well-defined cell populations. Only such studies will be able to reveal the important differences in gene regulation between different ce

Atmospheric Chemical Transport Based on High Resolution Model- Derived Winds: A Case Study

Flight 10 of NASA's Subsonic Assessment (SASS) Ozone and Nitrogen Oxide Experiment (SONEX) extended southwest of Lajes, Azores. A variety of chemical signatures were encountered. These signatures are examined in detail, relating them to meteorological data from a high resolution numerical model having horizontal grid spacing of 30 and 90 km and 26 vertical levels. The meteorological output at hourly intervals is used to create backward trajectories from the locations of the chemical signatures. Four major categories of chemical signatures are discussed-stratospheric, lightning, continental pollution, and a transition layer. The strong stratospheric signal is encountered just south of the Azores in a region of depressed tropopause height. Three chemical signatures at different altitudes in the upper troposphere are attributed to lightning. Backward trajectories arriving at locations of these signatures are related to locations of cloud-to-ground lightning. Results show that the trajectories pass through regions of lightning 1-2 days earlier over the eastern Gulf of Mexico and off the southeast coast of the United States. The lowest leg of the flight exhibits a chemical signature consistent with continental pollution. Trajectories arriving at this signature are found to pass over the highly populated Northeast Corridor of the United States. Surface based pollution apparently is lofted to the altitudes of the trajectories by convective clouds along the East Coast that did not contain lightning. Finally, a chemical transition layer is described. Its chemical signature is intermediate to those of lightning and continental pollution. Trajectories arriving in this layer pass between the trajectories of the lightning and pollution signatures. Thus, they probably are impacted by both sources

Medication Use Patterns among Urban Youth Participating in School-Based Asthma Education

Although pharmaceutical management is an integral part of asthma control, few community-based analyses have focused on this aspect of disease management. The primary goal of this analysis was to assess whether participation in the school-based Kickin’ Asthma program improved appropriate asthma medication use among middle school students. A secondary goal was to determine whether improvements in medication use were associated with subsequent improvements in asthma-related symptoms among participating students. Students completed an in-class case-identification questionnaire to determine asthma status. Eligible students were invited to enroll in a school-based asthma curriculum delivered over four sessions by an asthma health educator. Students completed a pre-survey and a 3-month follow-up post-survey that compared symptom frequency and medication use. From 2004 to 2007, 579 participating students completed pre- and post-surveys. Program participation resulted in improvements in appropriate use across all three medication use categories: 20.0% of students initiated appropriate reliever use when “feeling symptoms” (p < 0.001), 41.6% of students reporting inappropriate medication use “before exercise” initiated reliever use (p < 0.001), and 26.5% of students reporting inappropriate medication use when “feeling fine” initiated controller use (p < 0.02). More than half (61.6%) of participants reported fewer symptoms at post-survey. Symptom reduction was not positively associated with improvements in medication use in unadjusted and adjusted analysis, controlling for sex, asthma symptom classification, class attendance, season, and length of follow-up. Participation in a school-based asthma education program significantly improved reliever medication use for symptom relief and prior-to-exercise and controller medication use for maintenance. However, given that symptom reduction was not positively associated with improvement in medication use, pharmaceutical education must be just one part of a comprehensive asthma management agenda that addresses the multifactorial nature of asthma-related morbidity

A cryogenic beam of refractory, chemically reactive molecules with expansion cooling

Cryogenically cooled buffer gas beam sources of the molecule thorium monoxide (ThO) are optimized and characterized. Both helium and neon buffer gas sources are shown to produce ThO beams with high flux, low divergence, low forward velocity, and cold internal temperature for a variety of stagnation densities and nozzle diameters. The beam operates with a buffer gas stagnation density of ~10^15-10^16 cm^-3 (Reynolds number ~1-100), resulting in expansion cooling of the internal temperature of the ThO to as low as 2 K. For the neon (helium) based source, this represents cooling by a factor of about 10 (2) from the initial nozzle temperature of about 20 K (4 K). These sources deliver ~10^11 ThO molecules in a single quantum state within a 1-3 ms long pulse at 10 Hz repetition rate. Under conditions optimized for a future precision spectroscopy application [A C Vutha et al 2010 J. Phys. B: At. Mol. Opt. Phys. 43 074007], the neon-based beam has the following characteristics: forward velocity of 170 m/s, internal temperature of 3.4 K, and brightness of 3x10^11 ground state molecules per steradian per pulse. Compared to typical supersonic sources, the relatively low stagnation density of this source, and the fact that the cooling mechanism relies only on collisions with an inert buffer gas, make it widely applicable to many atomic and molecular species, including those which are chemically reactive, such as ThO

Ozone and aerosol distributions and air mass characteristics over the South Pacific during the burning season

In situ and laser remote measurements of gases and aerosols were made with airborne instrumentation to establish a baseline chemical signature of the atmosphere above the South Pacific Ocean during the NASA Global Tropospheric Experiment (GTE)/Pacific Exploratory Mission‐Tropics A (PEM‐Tropics A) conducted in August‐October 1996. This paper discusses general characteristics of the air masses encountered during this experiment using an airborne lidar system for measurements of the large‐scale variations in ozone (O3) and aerosol distributions across the troposphere, calculated potential vorticity (PV) from the European Centre for Medium‐Range Weather Forecasting (ECMWF), and in situ measurements for comprehensive air mass composition. Between 8°S and 52°S, biomass burning plumes containing elevated levels of O3, over 100 ppbv, were frequently encountered by the aircraft at altitudes ranging from 2 to 9 km. Air with elevated O3 was also observed remotely up to the tropopause, and these air masses were observed to have no enhanced aerosol loading. Frequently, these air masses had some enhanced PV associated with them, but not enough to explain the observed O3 levels. A relationship between PV and O3 was developed from cases of clearly defined O3 from stratospheric origin, and this relationship was used to estimate the stratospheric contribution to the air masses containing elevated O3 in the troposphere. The frequency of observation of the different air mass types and their average chemical composition is discussed in this paper