FARM PRICE AND INCOME ISSUES, 1965

Agricultural and Food Policy,

THE UNIVERSITY'S ROLE IN PROGRAMS ON RURAL POVERTY

Food Security and Poverty,

RESPONSIBILITIES OF LAND-GRANT UNIVERSITIES IN PUBLIC AFFAIRS EDUCATION

Teaching/Communication/Extension/Profession,

INCREASING MOBILITY OF LABOR THROUGH TRAINING PROGRAMS

Labor and Human Capital,

Model for a Nonlinear Tank System Under Proportional-Integral-Derivative Control

A model (NONLINRK) was developed for a closed tank system under feedback control by an ideal proportional-integral-derivative controller. Under servo action the fluid level in the tank is altered from its equilibrium set point. Under regulatory action the feed pressure to the inlet valve and/or the outlet valve percentage opening are varied from equilibrium settings. The numerical model uses Gill’s fourth-order Runge-Kutta algorithm to solve the system equation. The equation was made separable by approximating an exponential factor by the tangent at the beginning of each time step in the numerical solution. NONLINRK simulation trials exhibited many characteristics of linear system including unequal offset under proportional control for the setpoint changes equal in magnitude but opposite in sign, harmonics in the response to a sine wave input on fluid level setpoint and bounded response in spite of increased gain settings. In addition, further simulation trials showed the system response converges to that of a linear system for sufficiently small setpoint of load variations. A second model using the modeling language TUTSIM provided corroboration of the results produced by NONLINRK. Proportional and proportional-integral control simulations differed by less than .1% and the models showed the same rates of convergence as the time step was decreased. Under PID control TUTSIM simulations developed severe instabilities, but NONLINRK exhibited the expected trends in the increased ability to react to a ramp function disturbance and the decrease in phase lag in response to a sinusoidal setpoint function

Effects of harvesting methods on sustainability of a bay scallop fishery: dredging uproots seagrass and displaces recruits

Fishing is widely recognized to have profound effects on estuarine and marine ecosystems (Hammer and Jansson, 1993; Dayton et al., 1995). Intense commercial and recreational harvest of valuable species can result in population collapses of target and nontarget species (Botsford et al., 1997; Pauly et al., 1998; Collie et al. 2000; Jackson et al., 2001). Fishing gear, such as trawls and dredges, that are dragged over the seafloor inflict damage to the benthic habitat (Dayton et al., 1995; Engel and Kvitek, 1995; Jennings and Kaiser, 1998; Watling and Norse, 1998). As the growing human population, over-capitalization, and increasing government subsidies of fishing place increasing pressures on marine resources (Myers, 1997), a clear understanding of the mechanisms by which fishing affects coastal systems is required to craft sustainable fisheries management

Bishop Buddy Scrapbook 1937 (3)

This scrapbook emphasizes Bishop Buddy’s appointment as the Bishop of San Diego. It also chronicles Bishop Buddy’s installation ceremony and his first activities as Bishop. It shares the Bishop Buddy’s thoughts on political and social issues. This scrapbook also provides information on Bishop Buddy’s personal residence, the kidnapping of Reverend Gerard A. Donovan, the San Diego Diocese church directory, the San Diego mission system, and World Wide News of the Week. It consists mainly of newspaper clippings, pamphlets, and postcards.https://digital.sandiego.edu/buddy-scrapbooks/1001/thumbnail.jp

Guide to the Bishop Charles Francis Buddy Sermons and Photographs collection

This collection contains documents and photographs related to Bishop Charles Francis Buddy and the Catholic church. The majority of the documents are sermons given by Bishop Buddy. Photographs are primarily of Bishop Buddy and signed photographs given to Bishop Buddy. Finding Aids are tools used to aid research by describing the materials in a collection. Special Collections Finding Aids include historical and/or biographical information along with a description of the collection and a folder listing of the content. To view this collection please email University Archives and Special Collections staff at [email protected]://digital.sandiego.edu/findingaidssc/1007/thumbnail.jp

Tariff-Rate Quotas : Difficult to model or plain simple?

The difficulty of reliably and accurately incorporating tariffrate quotas (TRQs) into trade models has received a lot of attention in recent years. As a result of the Uruguay Round of GATT negotiations, TRQs replaced an assortment of tariff and nontariff instruments in an effort to standardise trade barriers, and facilitate their future liberalisation. Understanding the nuances of TRQs is now particularly crucial for New Zealand because of the preferential access arrangements that New Zealand has for a number of products in highly protected markets such as the European Union, Japan, and the United States. It has been argued that TRQs are complex instruments and are difficult to model because for any trade flow between two countries, one of three regimes may be applicable : 1. The import quota may not be binding and the within-quota tariff applies; 2. The quota may be binding, the within-quota tariff applies, and a quota rent is created; or 3. Trade occurs over and above the quota, in which case an over-quota tariff applies (although, even in this regime, someone is still able to collect the quota rent on within-quota trade). But even this characterisation, which many claim is too complex to model, is a major simplification of reality. Bilateral preferences are ubiquitous, and such preferences are usually included in the determination of multilateral market access quotas. It is usual, therefore, that the TRQ instrument has several tiers to the quota schedule, plus a number of within and over-quota tariff rates applicable on either a bilateral or a multilateral basis. Further trade liberalisation creates something of a dilemma for New Zealand. Any decrease in over-quota tariffs and/or increase in quota levels potentially reduces the value of quota rents, many of which accrue to New Zealand due to the bilateral preferences. It is important, therefore, that New Zealand trade negotiators understand how much additional trade is required to offset the loss of New Zealands quota rents. Modelling trade in the presence of TRQs is the only way to ascertain this knowledge. The purpose of this paper is to show that complex TRQs can be modelled very easily and precisely. The only catch is that the model must be formulated as a complementarity problem rather than the more conventional linear or nonlinear optimisation problem. The concept will be demonstrated using a simple 3-region, single commodity spatial price equilibrium model of trade.Tariff-rate quota, trade modelling, mathematical programming, complementarity