History of a Problem Solving Course for Pre-Service K-8 Teachers

James Madison University\u27s mathematics course in problem solving for prospective K-8 teachers has gone through many changes since we introduced it as a course for prospective middle school teachers four years ago. This paper will discuss the original design of the course, the changes made and their reasons, and the current state of the course

A hazard model for welfare durations with unobserved location-specific effects

Many papers have investigated how personal characteristics and environmental variables affect welfare durations of unmarried mothers. This paper estimates proportional hazard models for welfare durations that allow for either fixed state or fixed labor market area effects. Conditioning on residence location by fixed effects can limit the impact of three types of potential bias. (1) Estimates of the effects of personal characteristics can be biased owing to the omission of relevant local area variables. (2) Estimates of the impact of state welfare benefit levels are biased because they proxy for other unmeasured attributes of the state, in particular, the entire state welfare system. Conditioning on state fixed effects limits this bias to the extent that we can use time variation within states to estimate the benefit level effect. (3) With state fixed effects, we can better estimate the impact of local conditions, such as unemployment rates, because they also may have been picking up omitted state-level effects. The models are estimated by the Cox partial likelihood method with time-varying covariates. Data come from the 1984 and 1985 panels of the Survey of Income and Program Participation. I find that some personal characteristics (being black or Hispanic, education) have greater impact after controlling for location-specific effects.

Inventories and the business cycle: an overview

A review of research on the relationship between inventory investment and business cycle fluctuations, focusing on the developments of the last 15 years. A central issue in the literature, the relative importance of demand and supply shocks as sources of fluctuations, continues to be debated.Inventories ; Business cycles

An introduction to the search theory of unemployment

The author presents a model of job search that focuses on an unemployed person's decision to accept an offered job or to continue looking for a new one.Unemployment

Money growth and inflation: how long is the long run?

In their efforts to maintain low inflation, policymakers pay little attention to the growth rate of the money supply. Yet many studies have found that money growth and inflation a closely related, at least in the long run. But how long must money growth remain strong before it begins to concern policymakers? That is, what is the shortest period over which money growth seems to be reliably associated with inflation?Inflation (Finance) ; Money supply ; Monetary policy

Research investigation of helicopter main rotor/tail rotor interaction noise

Acoustic measurements were obtained in a Langley 14 x 22 foot Subsonic Wind Tunnel to study the aeroacoustic interaction of 1/5th scale main rotor, tail rotor, and fuselage models. An extensive aeroacoustic data base was acquired for main rotor, tail rotor, fuselage aerodynamic interaction for moderate forward speed flight conditions. The details of the rotor models, experimental design and procedure, aerodynamic and acoustic data acquisition and reduction are presented. The model was initially operated in trim for selected fuselage angle of attack, main rotor tip-path-plane angle, and main rotor thrust combinations. The effects of repositioning the tail rotor in the main rotor wake and the corresponding tail rotor countertorque requirements were determined. Each rotor was subsequently tested in isolation at the thrust and angle of attack combinations for trim. The acoustic data indicated that the noise was primarily dominated by the main rotor, especially for moderate speed main rotor blade-vortex interaction conditions. The tail rotor noise increased when the main rotor was removed indicating that tail rotor inflow was improved with the main rotor present

An assessment of apple varieties for their suitability in organic production systems

Twenty seven varieties of apple were assessed for their susceptibility to apple scab, mildew and rosy apple aphid in a replicated experiment at East Malling Research. The varieties most affected by mildew were Goldrush, DL11, Liberty, Bohemia and Pinova. Ceeval, Discovery, Edward VII, Howgate Wonder, Rajka, Rebella and Topaz had the lowest incidences of mildew. The highest incidence of scab occurred on Pilot and Pinova, but infestation was low throughout the assessment period. In 2006 when aphid populations were high, Liberty, Goldrush and Delorina had no aphid infestations, and low infestations were seen on Edward VII, Resi and Santana