Cross Border Business Cycle Impacts on the El Paso Housing Market

There is comparatively little empirical evidence regarding the impacts of cross border business cycle fluctuations on metropolitan housing markets located near international boundaries. This study examines the impacts of economic conditions in Mexico on sales of existing single-family houses in El Paso, Texas. Anecdotal evidence suggests that these impacts are fairly notable. Annual frequency data from the University of Texas at El Paso Border Region Modeling Project are used to test this possibility. Results indicate that solid empirical evidence of such a linkage is elusive.Business Cycles, Border Housing Markets

Attitudes towards Privateering during the Era of the Early American Republic

Lacking sufficient funds to build and maintain a sizeable navy, the young United States was forced to employ privateers as a “stop-gap navy” in its struggles against stronger sea powers during the War for Independence, the Quasi War, and the War of 1812. Many American leaders opposed privateering on moral grounds, but felt compelled to employ it. Merchants and seamen were generally more supportive, wither because their usual employment, fishing and peaceful commerce, was denied them when enemies hovered outside American ports and began seizing American ships, or because privateering offered the prospect of quick and large profits. Sailors preferred service in privateers to enlisting in the navy because discipline tended to be less rigorous in privateers than in warships, privateers appeared safer since their captains generally tried to avoid combat with enemy men of war, and privateers offered the prospect of more prize money from the sale of captured ships. Officers in the Continental and United States Navy usually opposed privateering because privateers competed with them for recruits and for naval stores to fit their ships out for sea. Though controversial, it cannot be denied that privateering proved effective. The attacks launched by the private vessels on British and French commerce forced those governments to assign naval forces to protect their shipping. At home, privateering brought a level of prosperity to several American seaports that those communities had not experienced before. Despite its development of a regular navy during the nation’s first half century of independence, the United States continued to employ privateering as an integral part of its defense policy, attitudes toward the practice remained the same, merchants eagerly invested in privateering expeditions, and sailors viewed it as an attractive alternative to service in the regular Navy

On Novices\u27 Interaction with Compiler Error Messages: A Human Factors Approach

The difficulty in understanding compiler error messages can be a major impediment to novice student learning. To alleviate this issue, multiple researchers have run experiments enhancing compiler error messages in automated assessment tools for programming assignments. The conclusions reached by these published experiments appear to be conflicting. We examine these experiments and propose five potential reasons for the inconsistent conclusions concerning enhanced compiler error messages: (1) students do not read them, (2) researchers are measuring the wrong thing, (3) the effects are hard to measure, (4) the messages are not properly designed, (5) the messages are properly designed, but students do not understand them in context due to increased cognitive load. We constructed mixed-methods experiments designed to address reasons 1 and 5 with a specific automated assessment tool, Athene, that previously reported inconclusive results. Testing student comprehension of the enhanced compiler error messages outside the context of an automated assessment tool demonstrated their effectiveness over standard compiler error messages. Quantitative results from a 60 minute one-on-one think-aloud study with 31 students did not show substantial increase in student learning outcomes over the control. However, qualitative results from the one-on-one thinkaloud study indicated that most students are reading the enhanced compiler error messages and generally make effective changes after encountering them

Oxidation in a temperature gradient

The effects of a temperature gradient and heat flux on point defect diffusion in protective oxide scales were examined. Irreversible thermodynamics were used to expand Fick's first law of diffusion to include a heat flux term--a Soret effect. Oxidation kinetics were developed for the oxidation of cobalt and for nickel doped with chromium. Research in progress is described to verify the effects of a heat flux by oxidizing pure cobalt in a temperature gradient above 800 C, and comparing the kinetics to isothermal oxidation. The tests are being carried out in the new high temperature gaseous corrosion and corrosion/erosion facility at the Albany Research Center

Hot Corrosion at Air-Ports in Kraft Recovery Boilers

Hot corrosion can occur on the cold-side of airports in Kraft recovery boilers. The primary corrosion mechanism involves the migration of sodium hydroxide and potassium hydroxide vapors through leaks in the furnace wall at the airports and their subsequent condensation. It has been reported that stainless steel is attacked much faster than carbon steel in composite tubes, and that carbon steel tubing, when used with a low-chromium refractory, does not exhibit this type of corrosion. For hot corrosion fluxing of metal oxides, either acidic or basic fluxing takes place, with a solubility minimum at the basicity of transition between the two reactions. For stainless steel, if the basicity of the fused salt is between the iron and chromium oxide solubility minima, then a synergistic effect can occur that leads to rapid corrosion. The products of one reaction are the reactants of the other, which eliminates the need for rate-controlling diffusion. This effect can explain why stainless steel is attacked more readily than carbon steel

Irruptions: evidence for breeding season habitat limitation in Piping Plover (Charadrius melodus)

Effective management of wildlife populations requires identification of the factors limiting their growth. The Piping Plover (Charadrius melodus) is an imperiled, disturbance-dependent, shorebird species that nests on broad, sparsely vegetated beaches, sandbars, and lakeshores. In areas minimally affected by human use, plover habitat loss occurs through vegetation encroachment and erosion. Alternatively, habitat availability may be increased by sand deposition caused by storm- or flood-induced sediment transport or scouring that removes vegetation, or by receding lake levels. To test the hypothesis that plover populations are limited by available breeding habitat, we estimated the amount of habitat available before and after four significant storm and flooding events (i.e., disturbance) by classifying pre- and postdisturbance aerial imagery. We then evaluated the population changes that occurred after disturbance-related habitat alterations. Additionally, we report on population changes from four population increases that occurred after habitat creation events for which we did not have imagery suitable for classification. The storm and flood effects considered were those from hurricanes and nor’easters on barrier islands of Virginia, North Carolina, New York, and Maryland, USA, and those from floods and high water output from the Gavins Point Dam on the Missouri River between South Dakota and Nebraska, USA. The amount of nesting habitat increased 27–950% at these sites, and plover populations increased overall 72–622% after these events (increase of 8–217 pairs in 3 to 8 years after the disturbance, average 12–116% increase annually). The demographic changes were driven by productivity in some cases and probably by increases in immigration in others, and occurred simultaneously with regional increases. Our results support our hypothesis that the focal plover populations were at or near carrying capacity and are habitat limited. Currently, human interventions such as beach stabilization, the construction of artificial dunes, and dams reduce natural disturbance, and therefore, the carrying capacity, in many plover breeding areas. If these interventions were reduced or modified in such a way as to create and improve habitat, plover populations would likely reach higher average numbers and the potential for achieving recovery goals would be increased

NASA information sciences and human factors program

The FY-90 descriptions of technical accomplishments are contained in seven sections: Automation and Robotics, Communications, Computer Sciences, Controls and Guidance, Data Systems, Human Factors, and Sensor Technology