Borders, Common Currencies, Trade, and Welfare: What Can We Learn from the Evidence?

Recent evidence indicates that the intensity of economic exchange within and across borders is significantly different: linkages are much tighter within, than among, nation-states. These findings, however, do not necessarily imply that borders and separate national currencies represent significant barriers to trade that should be removed, since the evidence is also consistent with the alternative hypothesis, that domestic exchange is more efficient because domestic producers are better able to satisfy the requirements of local consumers, owing to common tastes and institutions and the existence of local information and social networks. Focusing primarily on trade linkages within and between Canada and the United States, the authors review the evidence on the extent to which national borders lessen the intensity of international economic linkages, primarily trade in goods and services, and the effects on domestic welfare. They also examine the evidence on the impact of common currencies on trade and welfare. They determine that, since the empirical models employed to date in this research cannot distinguish between alternative explanations of the evidence, it is not yet possible to draw firm conclusions for policy-making.

Data base architecture for instrument characteristics critical to spacecraft conceptual design

Spacecraft designs are driven by the payloads and mission requirements that they support. Many of the payload characteristics, such as mass, power requirements, communication requirements, moving parts, and so forth directly affect the choices for the spacecraft structural configuration and its subsystem design and component selection. The conceptual design process, which translates mission requirements into early spacecraft concepts, must be tolerant of frequent changes in the payload complement and resource requirements. A computer data base was designed and implemented for the purposes of containing the payload characteristics pertinent for spacecraft conceptual design, tracking the evolution of these payloads over time, and enabling the integration of the payload data with engineering analysis programs for improving the efficiency in producing spacecraft designs. In-house tools were used for constructing the data base and for performing the actual integration with an existing program for optimizing payload mass locations on the spacecraft

Evaluation of ERBE scanner pointing accuracy based upon a coastline detection algorithm

Measurements from the Earth Radiation Budget Experiment (ERBE) scanning radiometers must be accurately located at the top of the Earth's atmosphere for proper interpretation of derived longwave and shortwave components of the Earth radiation field. The accuracy of the location calculations is affected by the orbit characteristics and attitude control systems of the three spacecraft, ERBS, NOAA-9, and NOAA-10. A technique was developed which makes use of the longwave scanner measurements to detect the thermal gradients at the boundaries of ocean and land masses. By analyzing many such coastline boundaries, estimates of the overall accuracy of the scanner measurement location calculations have been derived for the three satellites. The resulting measurement location errors are found to be smaller than the resolution of the radiometers, and this accuracy is well within the required location knowledge for useful science analysis of the ERBE scanner data

Novel tretinoin 0.05% lotion for the once-daily treatment of moderate-to-severe acne vulgaris in a preadolescent population.

BackgroundAcne vulgaris (acne) is a common skin condition in children and adolescents. Efficacy of tretinoin is well documented in studies that included pediatric patients (12-18 years of age). With acne routinely presenting in younger patients, data are needed in this important group. Lotion formulations are commonly used across dermatology and are well liked by patients.ObjectiveTo evaluate the safety and efficacy of a novel once-daily tretinoin 0.05% lotion in preadolescent subjects (≤ 13 years) with moderate-to-severe acne.MethodsPost hoc analysis of two multicenter, randomized, double-blind, vehicle-controlled phase 3 studies in moderate-to-severe acne. Preadolescent subjects (N = 154) randomized (1:1) to receive tretinoin 0.05% lotion or vehicle, once daily for 12 weeks. Efficacy assessments included changes in baseline inflammatory/noninflammatory lesions and treatment success (at least 2-grade reduction in Evaluator's Global Severity Score [EGSS] and clear/almost clear). Safety, adverse events (AEs), and cutaneous tolerability evaluated throughout.ResultsAt Week 12, mean percent reduction in inflammatory and noninflammatory lesion counts were 49.5% and 44.0% compared with 31.4% and 18.8% with vehicle (both P = 0.001). Treatment success was achieved by 23.7% of subjects by Week 12, compared with 7.2% (P = 0.009). The majority of AEs were mild and transient: most frequently were application site pain (5.6%) and application site dryness (2.8%). Local cutaneous safety and tolerability assessments were generally mild-to-moderate and improved by Week 12.ConclusionsTretinoin 0.05% lotion was significantly more effective than vehicle in achieving treatment success and reducing inflammatory and noninflammatory lesions in preadolescent acne. It was well tolerated, with all treatment-related AEs deemed mild or moderate

Thermal and structural tests of Rene 41 honeycomb integral-tank concept for future space transportation systems

Two flat 12 by 72 inch Rene 41 honeycomb sandwich panels were tested in a manner to produce combined thermal and mechanical longitudinal stresses that simulated those that would occur in a larger, more complex integral tank and fuselage structure of an earth to orbit vehicle. Elastic strains measured at temperatures below 400 F are compared with calculated values obtained from a linear elastic finite element analysis to verify the analytical model and to establish confidence in the calculated strains. Elastic strain measurement at higher temperatures (between 600 F and 1400 F), where strain measurement is more difficult and less certain, are also compared with calculated strains. Agreement between measured and calculated strains for the lower temperatures is good, but agreement for the higher temperatures is poor because of unreliable strain measurements. Test results indicate that an ascent and entry life cycle of 500 is attainable under high combined thermal and mechanical elastic strains

Contrasting the beam interaction characteristics of selected lasers with a partially stabilised zirconia (PSZ) bio-ceramic

Differences in the beam interaction characteristics of a CO2 laser, a Nd:YAG laser, a high power diode laser (HPDL) and an excimer laser with a partially stabilised zirconia (PSZ) bio-ceramic have been studied. A derivative of Beer-Lambert’s law was applied and the laser beam absorption lengths of the four lasers were calculated as 33.55 x 10-3 cm for the CO2 laser, 18.22 x 10-3 cm for the Nd:YAG laser, 17.17 x 10-3 cm for the HPDL and 8.41 x 10-6 cm for the excimer laser. It was determined graphically that the fluence threshold values at which significant material removal was effected by the CO2 laser, the Nd:YAG laser, the HPDL and the excimer laser were 52 J/cm2, 97 J/cm2, 115 J/cm2 and 0.48 J/cm2 respectively. The thermal loading value for the CO2 laser, the Nd:YAG laser, the HPDL and the excimer laser were calculated as being 1.55 kJ/cm3, 5.32 kJ/cm3, 6.69 kJ/cm3 and 57.04 kJ/cm3 respectively

Measurement of Protein in Nearshore Marine Sediments

Proteinaceous material in marine sediments which is available to proteolytic hydrolysis has been measured using a new method. This technique utilizes Coomassie Blue dye binding, which has the advantage of being sensitive only to larger polypeptides. Substantial interferences from other sedmentary organic substances are overcome by using a standard additions approach in conjunction with enzymatic digestion of the protein. Although tedious, the technique provides acceptable precision and accuracy. Measurements of protein in surficial nearshore sediments of the Gulf of Maine and St. Croix yield values ranging from 0.1 to 2.2 mg g-1, which account for a minor fraction of total nitrogen or acid-hydrolyzable amino acids. Protein decreases downcore at a faster rate than either of these 2 indicators of nitrogenous material, indicating the greater lability of the truly proteinaceous material. Biomass comprises a minor portion of the measured protein