Fertilizer production functions for corn and oats; Including an analysis of irrigated and residual response

This study includes predictions of fertilizer production functions for four experiments. The experiments on Clarion and McPaul soils contain predictions of total and marginal yields, isoquants and marginal rates of substitution, isoclines and economic optima. Similar analyses for the other two experiments, conducted on Carrington soil during successive growing seasons, were not warranted because insufficient rainfall limited yield responses. The experiments included in this study were based on partially replicated factorial designs. The experiment with corn on Clarion silt loam in 1954 included nitrogen, phosphorus and potash as variable nutrients. The production function, isoquants and isoclines are represented by equations a, b, c, d, e, f and g. In these equations (and equations listed below), N, P and K denote the pounds per acre of nitrogen, P2O5 and K20, respectively. Isoquant and isocline equations were derived for each pair of nutrients. Hence, there are three of each of these equations. The α in the isocline equations represents a constant price or substitution ratio

Production surfaces and economic optima for corn yields with respect to stand and nitrogen levels

This study presents production functions for three experiments on corn in Iowa. It is fourth in a series of studies designed to derive corn response surfaces, yield isoquants and economic optima in fertilizer use.:! It differs from previous studies in that, for the first time, stand (plant population) is included as a variable input along with a plant nutrient (nitrogen). The analysis permits estimation of yield response to stand and to nitrogen as well as to the interaction between stand and nitrogen. Knowledge of this type is relevant, not only for farm recommendations, but also for improved planning of fertilization experiments. The first experiment reported involved stand levels on Shelby loam and was conducted in Ringgold County in 1956. The other two experiments reported were conducted in 1953, with variable stand and nitrogen levels on Marshall and Seymour silt loams, respectively, and were located in Fremont and Wayne counties.3 Each of these experiments included an early and an adapted variety of corn (Iowa 4297 or Iowa 4397 and A.E.S. 801, respectively)

Critical Casimir effect and wetting by helium mixtures

We have measured the contact angle of the interface of phase-separated $^{3}$He-$^{4}$He mixtures against a sapphire window. We have found that this angle is finite and does not tend to zero when the temperature approaches $T_t$, the temperature of the tri-critical point. On the contrary, it increases with temperature. This behavior is a remarkable exception to what is generally observed near critical points, i.e. "critical point wetting''. We propose that it is a consequence of the "critical Casimir effect'' which leads to an effective attraction of the $^{3}$He-$^{4}$He interface by the sapphire near $T_{t}$.Comment: submitted july 13 (2002), published march 20 (2003

Estimating Small Area Income Deprivation: An Iterative Proportional Fitting Approach

Small area estimation and in particular the estimation of small area income deprivation has potential value in the development of new or alternative components of multiple deprivation indices. These new approaches enable the development of income distribution threshold based as opposed to benefit count based measures of income deprivation and so enable the alignment of regional and national measures such as the Households Below Average Income with small area measures. This paper briefly reviews a number of approaches to small area estimation before describing in some detail an iterative proportional fitting based spatial microsimulation approach. This approach is then applied to the estimation of small area HBAI rates at the small area level in Wales in 2003-5. The paper discusses the results of this approach, contrasts them with contemporary ‘official’ income deprivation measures for the same areas and describes a range of ways to assess the robustness of the results

Taxing the Informal Economy: The Current State of Knowledge and Agendas for Future Research

This paper reviews the literature on taxation of the informal economy, taking stock of key debates and drawing attention to recent innovations. Conventionally, the debate on whether to tax has frequently focused on the limited revenue potential, high cost of collection, and potentially adverse impact on small firms. Recent arguments have increasingly emphasised the more indirect benefits of informal taxation in relation to economic growth, broader tax compliance, and governance. More research is needed, we argue, into the relevant costs and benefits for all, including quasi-voluntary compliance, political and administrative incentives for reform, and citizen-state bargaining over taxation