DEMAND SYSTEM CHOICE BASED ON TESTING THE ENGEL CURVE SPECIFICATION

It is common to use a demand systems approach in estimating the key parameters from household consumption data. In conducting these studies the researcher is faced with selecting a functional form. In turn, each functional form implies a particular shape for the Engel curves. This analysis highlights the importance of testing the shape of Engel curves, especially if the researcher is interested in elasticity estimates well away from the sample mean. Using consumption data for selected households in Italy it is shown that many popular functional forms are rejected by the data.Demand and Price Analysis,

TRADE LIBERALIZATION UNDER NAFTA: WHERE FROM HERE?

International Relations/Trade,

Comparison of jet Mach number decay data with a correlation and jet spreading contours for a large variety of nozzles

Small-scale circular, noncircular, single- and multi-element nozzles with flow areas as large as 122 sq cm were tested with cold airflow at exit Mach numbers from 0.28 to 1.15. The effects of multi-element nozzle shape and element spacing on jet Mach number decay were studied in an effort to reduce the noise caused by jet impingement on externally blown flap (EBF) STOL aircraft. The jet Mach number decay data are well represented by empirical relations. Jet spreading and Mach number decay contours are presented for all configurations tested

Low frequency noise in a quiet, clean, general aviation turbofan engine

A quiet, clean, general aviation, turbofan engine was instrumented to measure the fluctuating pressures in the combustor, turbine exit duct, engine nozzle and the far field. Both a separate flow nozzle and an internal mixer nozzle were tested. The fluctuating pressure data are presented in overall pressure and power levels and in spectral plots. The combustor data are compared to recent theory and found to be in excellent agreement. The results indicate that microphone correction procedures for elevated mean pressures are questionable. Ordinary coherence function analysis suggests the presence of an additional low frequency noise source downstream of the turbine that is due to the turbine itself. Low frequency narrowband data and coherence function analysis are presented

People are more likely to describe a violent event as terrorism if the perpetrator is Muslim and has policy goals

Recent mass shootings in the US have provoked debate over what should be considered to be "terrorism". In new research Connor Huff and Joshua D. Kertzer explore these public debates via a survey which seeks to determine which kinds of incidents - and perpetrators - mean that people are more likely to classify an event as terrorism. They find that ..

Modeling Bioterrorism in the Livestock Sectors of NAFTA Members

Until two years ago, most citizens of Canada, the United States and Mexico experienced terrorism as a distant reality viewed from the safety of their living rooms. Today, North Americans encounter constant reminders of the aggravation and economic costs imposed on them by the now real threat of terrorism. The United States, the most obvious target for new terrorist activity, has responded by tightening its border security with all countries including its NAFTA partners.(2) Canada and Mexico joined the NAFTA to obtain preferred and more secure access to the United States market. The increased threat of terrorist activity in North America raises three crucial questions for NAFTA members. First, how real is a bioterrorism threat? Second, how can the United States maintain access to its market for its NAFTA partners and at the same time meet its legitimate security concerns? Third, what are the potential economic effects of a bioterrorism attack on North America? While it is generally assumed that the United States would be the primary target of a terrorist attack, Canada, Mexico or all three NAFTA countries could be targeted.Agricultural and Food Policy, International Relations/Trade,

Women in Mathematics: An Historical Account of Women\u27s Experiences and Achievement

For a long time, women have struggled to gain complete acceptance in the mathematics field. The purpose of this paper is to explore the history of women in the field of mathematics, the impact and experiences of current female mathematicians, and the common trends for women in the mathematics field, through literature review and personal interviews. This paper looks at the lives of four famous female mathematicians, as well as female mathematicians in the Claremont Colleges who were interviewed for this paper. Specifically this paper examines the discrimination they faced and how they overcame this discrimination, as well as the contributions they have made to the mathematics field. In addition, studies about the effects of gender on mathematics achievement were explored. This paper tries to bring the conclusions of these studies together to present arguments from different perspectives. It also recognizes trends and changes in favor of women in the mathematics field in recent years. In spite of the contributions made by women and the improvements that have come about for women in the field, including the increased number of doctoral recipients, women still face challenges in gaining complete acceptance. Continued change can occur through mentoring and encouraging young women to pursue careers in the mathematics field

Microbial biofilm studies of the environmental control and life support system water recovery test for Space Station Freedom

NASA is developing a water recovery system (WRS) for Space Station Freedom to reclaim human waste water for reuse by astronauts as hygiene or potable water. A water recovery test (WRT) currently in progress investigates the performance of a prototype of the WRS. Analysis of biofilm accumulation, the potential for microbially influenced corrosion (MIC) in the WRT, and studies of iodine disinfection of biofilm are reported. Analysis of WRT components indicated the presence of organic deposits and biofilms in selected tubing. Water samples for the WRT contained acid-producing and sulfate-reducing organisms implicated in corrosion processes. Corrosion of an aluminum alloy was accelerated in the presence of these water samples; however, stainless steel corrosion rates were not accelerated. Biofilm iodine sensitivity tests using an experimental laboratory scale recycled water system containing a microbial check valve (MCV) demonstrated that an iodine concentration of 1 to 2 mg/L was ineffective in eliminating microbial biofilm. For complete disinfection, an initial concentration of 16 mg/L was required, which was gradually reduced by the MCV over 4 to 8 hours to 1 to 2 mg/L. This treatment may be useful in controlling biofilm formation

Peak axial-velocity decay with multi-element rectangular and triangular nozzles

The aircraft noise created by the impingement of engine exhaust jet of STOL aircraft with externally blown flaps is discussed. It was determined that the jet-flap interaction noise can be lowered by reducing the impinging velocity of the jet. The reduction must occur at a specific distance from the flap to be effective. The peak axial-velocity decay obtained with rectangular and triangular single element mixer nozzles is presented. Equations are developed for estimating the peak axial velocity decay curves for a wide range of nozzle configurations