The mathematical theory of linear systems, which has been used successfully to describe behavior maintained by variable-interval schedules, is extended to describe behavior maintained by variable-ratio schedules. The result of the analysis is a pair of equations, one of which expresses response rate on a variable-ratio schedule as a function of the mean ratio requirement (n) that the schedule a...

seismic ground motion is profoundly affected by geometrical and mechanical properties of soil deposits overlaying bedrock. local seismic ground response of saturated soil deposits was studied in literature by applying the effects of soil stress state and index properties on the strain-dependent normalized shear modulus reduction, g/g0, and damping ratio, d, curves in an equivalent linear analys...

this work presents thermoplastic analysis of fg rotating diskswith variable thickness and constant angular velocity. the solutions are obtained by variable material property (vmp) theory. in this theory, the domain is divided into some finite sub-domains in the radial direction, in which the properties are assumed to be constant and the form of the elastic response is used to solve elastic-plas...

variable rate application (vra) based on site specific crop management (sscm) is an effective approach for optimizing the application of agricultural inputs and preventing the undesirable environmental impacts. design, construction and evaluation of a map-based vra system was the main objective followed in this research. for variable rate application based on the generated map, a direct injecti...

Background: The emergency medical services system has a vital role in the timely treatment of victims and the reduction of injury and mortality rates. Ambulance response time is an essential variable in evaluating the quality of its services. The aim of this study was to determine the ambulance response time and to compare it according to background variables. Methods: This descriptive study ...

despite controversy, the contingent valuation method (cvm) is widely used for non-market valuation. among elicitation methods of cvm, the dichotomous choice (dc) has been paid attention. there are two types of dc methods: single-bounded dc (sbdc) and double-bounded dc (dbdc). dbdc is more efficient than sbdc. many of cvm studies in iran used dbdc but data analyses were done by logit model; that...

searching efficiency and handling time are two major components of functional response and are usually used to evaluate effectiveness of natural enemies. the effect of different foraging periods on the functional response of larval aphidoletes aphidimyza (rondani) (dip.: cecidomyiidae) feeding on third instar nymphs of aphis craccivora was studied. the experiment was conducted in terms of time-...