APPLICATION OF THE ECONOMIC THRESHOLD FOR INTERSEASONAL PEST CONTROL

We show how an interseasonal pest control problem can be simplified to enable an intraseasonal model to be empirically applied, extending the range of application of the intraseasonal model. Three alternative economic thresholds are compared. The optimal solution requires repeated computations by the farmer to compute the profit maximizing dose, with a corresponding threshold, for each pest infestation. Two alternative decision rules require a single computation by the farmer for the threshold and dosage rate. An empirical illustration shows that, relative to the optimal solution which is computationally burdensome to the farmer, little net revenue is lost by using one of the thresholds based upon a simpler decision rule.Farm Management,

Darwinian Selection and Non-existence of Nash Equilibria

We study selection acting on phenotype in a collection of agents playing local games lacking Nash equilibria. After each cycle one of the agents losing most games is replaced by a new agent with new random strategy and game partner. The network generated can be considered critical in the sense that the lifetimes of the agents is power law distributed. The longest surviving agents are those with the lowest absolute score per time step. The emergent ecology is characterized by a broad range of behaviors. Nevertheless, the agents tend to be similar to their opponents in terms of performance.Comment: 4 pages, 5 figure

The Status of School Reform in Pennsylvania Career and Technology Schools: Systemic Issues

The purpose of this study was to investigate the issues and implementation of high school reform efforts in the 81 career and technology schools in the Commonwealth of Pennsylvania. The specific areas that were examined were those identified in the research as contributing to high school reform efforts of secondary schools. The researcher developed four research questions that guided the study. Pennsylvania Association of Career and Technical Administrators (PACTA) aided the researcher in reaching directors of the 81 career and technology schools in the commonwealth via e-mail. The e-mail asked directors to complete an electronic survey concerning high school reform issues with their sending school districts. Seventy-one of a possible eighty-one directors completed the survey. The results of the completed survey were analyzed using quantitative and qualitative analysis. The statistical outline includes discussions of correlation, central themes found and percentages.The results of this study indicated that there is an overwhelming lack of communications between career and technology schools and their sending school districts. The researcher also found that comprehensive career and technology schools are more actively engaged in high school reform efforts than shared-time career and technology schools.By surveying a statistically significant number of career and technology school directors about the reform efforts of their schools, this study provides a clear road map for improvement in the overall high school reform efforts. This road map suggests Pennsylvania policymakers and school administrators need to make collaboration and communication a top priority to ensure that all students are provided the same high quality education regardless, of whether they chose career and technology or traditional academic education

Perhitungan Hidrostatik Untuk Badan kapal Yang Dibentuk dari Kurva B-Spline

Hidrostatik merupakan salah satu elemen yang tidak dapat tidak diperlukan untuk dipakai untuk dasar perencanaan kapal. Dengan dimulai memberi input yaitu berupa 'h Iebar badan kapal yang kemudian diolah menjadi persamaan parametris dan diproses dengan surface fitting sehingga menghasilkan vertek dalam ruang 3-D, dari data tersebut kemudian diolah melalui sejumlah rumusan, baik itu berupa luas, volume dan momen inersia yang pada akhimya menghasilkan ke-18 item kurva hidrostatik. Program ini diujikan dengan 'h bola dan perbedaanya dinyatakan dalam standart deviasi yang bervariasi mulai dari 6 digit dibelakang koma, hingga 1 digit dibelakang koma. Dimulai dari yang terkecil KB hingga WSA. Dari pengujian dan perbandingan program ini jika dibandingkan dengan tabulasi terhadap perhitungan analitis, didapatkan ketelitian yang bervariasi yaitu dimulai dari yang paling terkecil standart deviasinya yaitu KB sebesar 0.00000198 kemudian yang menengah yaitu TBM, TKM, LBM, LKM, Cb, Cp, Cm, Cw, berkisar antara 0.0002 s/d 0.0006, dan dilanjutkan yang paling besar standart deviasinya yaitu WPA, Displacemen dan WSA yaitu berkisar antara 0.03 s/d 0.7

Motion – Pancreatic Endoscopy is Useful for the Pain of Chronic Pancreatitis: Arguments Against the Motion

Endoscopic therapy can be used to dilate strictures in the pancreatic duct, remove stones and drain pseudocysts. In addition, it provides an alternative to surgery for the management of pain in patients with chronic pancreatitis. Pain is a difficult problem in these patients, especially if substance abuse is present, and its medical management is generally unsatisfactory. The concept that pancreatic pain is related to increased pressure in the main pancreatic duct is unproven, and is not supported by the results of surgical intervention. Although pancreatic stenting is often technically successful at achieving drainage of the pancreatic duct and relieving pain over the short term, pain usually recurs with time, complications are frequent, and repeated stent changes are usually necessary. Pancreatic pseudocysts can be drained endoscopically, using transpapillary, cystogastrostomy or cystoduodenostomy approaches, but success rates are less than 50% and bleeding is a major complication. Pseudocysts should not be drained unless they are symptomatic, causing complications or enlarging. There have been no published studies comparing endoscopic with surgical or radiological modalities. Endoscopic therapy of pancreatic disorders is a new and interesting technique, but initial promising results need to be confirmed in large, well-designed clinical trials. Such studies would need to enrol large numbers of patients, and involve measurement of technical success, pain severity and quality of life parameters. At present, endoscopic techniques must be considered experimental

The maximum density droplet to lower density droplet transition in quantum dots

We show that, Landau level mixing in two-dimensional quantum dot wave functions can be taken into account very effectively by multiplying the exact lowest Landau level wave functions by a Jastrow factor which is optimized by variance minimization. The comparison between exact diagonalization and fixed phase diffusion Monte Carlo results suggests that the phase of the many-body wave functions are not affected much by Landau level mixing. We apply these wave functions to study the transition from the maximum density droplet state (incipient integer quantum Hall state with angular momentum L=N(N-1)/2) to lower density droplet states (L>N(N-1)/2).Comment: 8 pages, 5 figures, accepted for publication in Phys. Rev.

Auger electron spectroscopy study of oxidation of a PdCr alloy used for high-temperature sensors

A Pd-13 wt. percent Cr solid solution is a promising high-temperature strain gage alloy. In bulk form it has a number of properties that are desirable in a resistance strain gage material, such as a linear electrical resistance versus temperature curve to 1000 C and stable electrical resistance in air at 1000 C. However, unprotected fine wire gages fabricated from this alloy perform well only to 600 C. At higher temperatures severe oxidation degrades their electrical performance. In this work Auger electron spectroscopy was used to study the oxidation chemistry of the alloy wires and ribbons. Results indicate that the oxidation is caused by a complex mechanism that is not yet fully understood. As expected, during oxidation, a layer of chromium oxide is formed. This layer, however, forms beneath a layer of metallic palladium. The results of this study have increased the understanding of the oxidation mechanism of Pd-13 wt. percent Cr

ECONOMIC THRESHOLDS UNDER UNCERTAINTY WITH APPLICATION TO CORN NEMATODE MANAGEMENT

An economic threshold of agricultural pest management is derived. Results provide a method for researchers to use in making improved pest control recommendations to farmers without farm level decision-making. An empirical illustration for lesion nematode management in irrigated corn is given and directions for further research are indicated.Crop Production/Industries, Risk and Uncertainty,