A Hawk-Dove game in kleptoparasitic populations

Kleptoparasitism, the parasitism by theft, is a widespread biological phenomenon. In this paper we extend earlier models to investigate a population of conspecifics involved in foraging and, potentially, kleptoparasitism. We assume that the population is composed of two types of individuals, Hawks and Doves. The types differ according to their strategic choices when faced with an opportunity to steal and to resist a challenge. Hawks use every opportunity to steal and they resist all challenges. Doves never resist and never steal. The fitness of each type of individual depends upon various natural parameters, for example food density, the handling time of a food item, density of the population, as well as the duration of potential fights over the food. We find the Evolutionarily Stable States (ESSs) for all arameter combinations and show that there are three possible ESSs, pure Hawks, pure Doves, and a mixed population of Hawks and Doves. We show that for any set of parameter values there is exactly one ESS. We further investigate the relationship between our findings and the classical Hawk-Dove game as defined in Maynard Smith 1982. We also show how our model extends the classical on

A method of hardware qualification for flight by analyses, similarity and integrated testing

The results are described of a study on four pieces of flight hardware from the Saturn 1U and S-4B stages to determine whether the objectives of the formal qualification tests on that hardware could have been obtained within that program by methods other than performing the qualification tests. These methods include qualification by analyses, similarity and integrated testing, i.e., distribution of the objectives among the other tests in the program. It was found that it is feasible to delete the requirements for formal qualification testing provided that it is accomplished early in the program to allow adequate planning for accomplishing the qualification objectives by other means. Additionally, a scorekeeping system was defined that is simple, straightforward, easy to implement. This scorekeeping system provides complete visibility of equivalent qualification status at any point during the program. A set of groundrules for implementing this study was established as a result of findings on the specific items of hardware studied

A game-theoretic model of kleptoparasitic behavior in polymorphic populations

Kleptoparasitism, the stealing of food by one animal from another, is a widespread biological phenomenon. In this paper we build upon earlier models to investigate a population of conspecifics involved in foraging and, potentially, kleptoparasitism. We assume that the population is composed of four types of individuals, according to their strategic choices when faced with an opportunity to steal and to resist an attack. The fitness of each type of individual depends upon various natural parameters, for example food density, the handling time of a food item and the probability of mounting a successful attack against resistance, as well as the choices that they make. We find the evolutionarily stable strategies (ESSs) for all parameter combinations and show that there are six possible ESSs, four pure and two mixtures of two strategies, that can occur. We show that there is always at least one ESS, and sometimes two or three. We further investigate the influence of the different parameters on when each type of solution occurs

Effect of Sodium Diacetate on Corn Silage Chemical Characteristics, Preservation and Utilization By Beef Steers

The purpose of this study was to compare untreate corn forage and forage treated with sodium diacetate in terms of chemical characteristics that occur during ensiling. Preservation of dry matter and utilization of nutrients by beef steers were also determined

Effect of Enzymes on Corn Silage Quality, Preservation and Utilization by Beef Steers

Research at the South Dakota Experiment Station has been directed toward methods of improving of corn silage making continues to be of interest to farmers and ranchers of South Dakota. The additives researched SDSU include viable and nonviable bacterial inoculants, organic acids, sodium diacetate, an ammonia-molasses-mineral suspension and enzymes

Untreated and Microbial Inoculated Corn Silage in High Silage Rations for Beef Steers

Results of research reported a year ago (CATTLE 81-3) indicated that corn silage inoculated with a Lactobacillus acidophilus fermentation product had lower temperatures during the fermentation period than untreated silage. Lactic and volatile fatty acid formation was also higher for the treated silage. Dry matter recovery was only slightly higher for the treated silage. Digestibility of dry matter, crude protein and organic matter by beef steers was similar for treated and untreated silage. The purpose of this experiment was to determine the effect of inoculating corn forage of high dry matter content with a Lactobacillus acidophilus fermentation product. Response to inoculation was compared with untreated silage in terms of feedlot performance of beef steers fed high silage rations. Preservation of silage dry matter and chemical quality were also determined

Effect of Lactobacillus Plantarum on Microbial Populations, Silage Qualit, Utilization and Preservation

The objective of this study was to determine the effect of treating corn forage with a Lactobacillus plantarum silage inoculant on corn silage quality. Response to inoculation was compared to untreated forage in terms of microbiological composition during the fermentation period, chemical characteristics and preservation of dry matter. The study also emphasized digestibility of nutrients and nitrogen utilization by beef steers

Simulation of condensation problems in a roller-skating centre

A commercial roller-skating centre in southern Australia had condensation problems on both the roof and floor. The building is a typical warehouse-type structure with a high level of natural ventilation due to poor construction and permanently open vents. A computer model of the building, using the thermal simulation software TRNSYS, was calibrated from a sensitivity analysis of three key parameters, namely air exchange rate, roof surface heat transfer coefficient and deep ground temperature. The predicted times of condensation on the roof were compared with site observations. The time of year was predicted with acceptable accuracy, although earlier in the morning than had been observed. The effect of installing foil insulation in the roof was simulated. Under normal winter conditions, this modification was enough to stop the condensation. However, in unusually cold and humid conditions, condensation still occurred on both surfaces. This was overcome by heating the floor (15 W/m 2 ) for approximately eight hours. Subsequent modifications have demonstrated the value of the simulations.<br /

Using small reverse cycle air conditioners in relocatable classrooms - a case study

A 9-month study of four relocatable school buildings, each retro-fitted with small reverse cycle air conditioners (ACs), was conducted to investigate their effectiveness in heating and cooling the classrooms. A comparison with data from previous studies found the energy used by the ACs for heating these temporary classrooms was only 19&ndash;20% of the energy used by individual gas heaters installed in permanent classrooms. When equipment efficiencies were considered, the AC units supplied 20&ndash;27% less energy to heat the classrooms. The possible reasons for this reduction in supplied energy are explored in this paper. CO2 emissions for the AC units in heating mode, however, were calculated to be 16% greater than for individual gas heaters. The AC units were also used for cooling and on an average the total annual energy consumption for heating and cooling was found to be 11.6 kWh m&minus;2. Responses to a small survey of staff and students about the use and operation of the conditioners are presented. Their responses were more favourable than the predictions of comfort levels in the classrooms using the Predicted Mean Vote&ndash;Predicted Percentage of Dissatisfaction (PMV&ndash;PPD) model, which indicated &ldquo;uncomfortable&rdquo; conditions on average summer days at 3:00 p.m. and average winter days at 10:00 a.m. Background noise levels in the classrooms with the air conditioners in use were above the recommended maximum design level of 45 dB(A); levels of up to 65 dB(A) were measured.<br /

The DMSP/MFR total ozone and radiance data base

This report describes the entries in sufficient detail so that the data base might be useful to others. The characteristics of the MFR sensor are briefly discussed and a complete index to the data base tapes is given