Numerous studies have explored the labor market of school principals, documenting high turnover rates and voicing concerns regarding labor supply. However, little is known about the staffing challenges in rural schools and what promotes applicants to apply for and be hired for principalship in these locales. In partnership with the Wisconsin Education Career Access Network, we examine the principal labor dynamics in rural schools using statewide job-openings and application information. Results indicate that all rural communities—rural fringe, rural distant, and rural remote—receive comparable numbers of applications, as compared with urban districts. Female candidates and candidates of color are significantly less likely to apply to rural districts, while experience working in the same district is a considerable advantage to being hired. Additionally, higher student poverty is associated with fewer principal applicants in rural schools. These results indicate the need for policies better attuned to subtle differences in rural contexts.
This paper develops a system instrumental variable method to estimate the speed of adjustment coefficient in the long-run equilibrium of structural error correction models for a class of linear rational expectations models. This method is applied to an exchange rate model with sticky prices, in which the speed of adjustment coefficient governs the half-life of the real exchange rate. Compared to single equation methods, the system method gives smaller half-life estimates with sharper standard errors. Copyright 2007 The Ohio State University.
Spent coffee grounds (SCG) are one of the lignocellulosic biomasses that have gained much attention due to their high potential both in valorization and biomethane production. Previous studies have reported single processes that extract either fatty acids/lignin or biogas. In this study, an integrated physicochemical and biological process was investigated, which sequentially recovers lignin, fatty acid methyl esters (FAME) and biogas from the residue of SCG. The determination of optimal conditions for sequential separation was based on central composite design (CCD) and response surface methodology (RSM). Independent variables adopted in this study were reaction temperature (86.1–203.9 °C), concentration of sulfuric acid (0.0–6.4%v/v) and methanol to SCG ratio (1.3–4.7 mL/g). Under determined optimal conditions of 161.0 °C, 3.6% and 4.7 mL/g, lignin and FAME yields were estimated to be 55.5% and 62.4%, respectively. FAME extracted from SCG consisted of 41.7% C16 and 48.16% C18, which makes the extractives appropriate materials to convert into biodiesel. Results from Fourier transform infrared spectroscopy (FT-IR) further support that lignin and FAME extracted from SCG have structures similar to previously reported extractives from other lignocellulosic biomasses. The solid residue remaining after lignin and FAME extraction was anaerobically digested under mesophilic conditions, resulting in a methane yield of 36.0 mL-CH4/g-VSadded. This study is the first to introduce an integrated resource recovery platform capable of valorization of a municipal solid waste stream.
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