Probability Of Movements Research Articles

Order Form and Information in Securities Markets

ABSTRACTThis paper examines the effects of price‐contingent orders on security prices. We show that a market maker who knows the type and composition of trades will set larger spreads and adjust prices faster than if price‐contingent orders were not allowed. Because traders have rational expectations over the book, we demonstrate that uncertainty over order type reduces the variance of prices but with a corresponding loss in price informativeness. We also show that the sequence property of price‐contingent orders increases the probability of large price movements. This distinction between variance and episodic price volatility has important policy implications.

A simple mathematical model for teaching diffusion in biology

A simple model of diffusion is described which is designed to help students understand the process in relation to the probability of molecular movements and the discretization of states in time. As with any model, it is only a partial representation of reality and the constraints governing it are discussed. Some practical applications of the model to school biology are described and some ways by which the model goes beyond students’ intuitive awareness of the topic are considered. The simple model can be developed considerably and refinements are briefly discussed.

The influence of an enkephalin derivative, DAGO, on the behavior and activity of neurons of the neocortex and hippocampus of rabbits during the development of defensive and inhibitory conditioned reflexes

After the administration of a morphine-like opiate, DAGO (D), in a dose of 250 micrograms/kg, a decrease was observed in the probability of movements of a rabbit in response to light flashes, the signal for a defensive reflex. The level of the background impulse activity of the neurons gradually decreased in the sensorimotor cortex and in the hippocampus, and did not change in the visual cortex. The decrease and the recovery of the responses of the neurons to the reinforcing stimulus (electrodermal stimulation of the limb) proceeded unidirectionally in all of the areas of the cortex studied, while there were substantial differences in the relationship to the cortical area studied and to the biological significance of the stimulus in the dynamics of the responses to the inhibitory and reinforced light flashes. The identification of the features of the systemic organization of the neurons during training with change in the properties of the reinforcement under the influence of the preparation under study is discussed, as well as the similarity of some features in the mechanisms of the development of internal inhibition in the defensive situation and of the properties of positive reinforcement.

Effect of substance P on behavior and cortical neuron activity during learning in rabbits

1. In experiments on conscious, loosely restrained rabbits, using a subcutaneously administered undecapeptide, substance P, in doses of 250 μg/kg, behavior and neuron activity was studied in the visual and sensorimotor areas of the neocortex and in the hippocampus during elicitation of the defense reflex conditioned to light flashes and conditioned inhibition. 2. Introduction of sP evoked a short-term loss of motor reactions to the reinforcing stimulus; a lowering in probability of movements to reinforced and inhibitory light flashes; and a prolonged quickening of heartrate and slowing of breathing rate. 3. The background action of sP, among the majority of investigated neurons responding to stimulus presentations, resulted in a fall in background activity and a weakening of excitatory and strengthening of inhibitory response components, especially to the painful reinforcing stimulus. Some neurons showed an increase in excitatory reactions. 4. Bioelectric indicators reflecting a strengthening of inhibitory hyperpolarization processes during internal inhibition were unaffected: inhibitory background pauses and evoked activity in cerebral cortex neurons, together with corresponding slow potential fluctuations, were unchanged by sP.

The Failure of the South Pass 70 Platform B in Hurricane Camille

In Aug. 1969 Shell Oil Co.'s Platform B, located in the OCS-designated South Pass Block 70, went down in Hurricane Camille. An intensive study was undertaken to determine the cause of platform failure. The data conclusively show that the structure failed primarily because of sea-floor soil movement. Introduction South Pass Block 70 is located about 15 miles southeast of the Main Pass on the Mississippi River (see Fig. 1). In preparation for the installation of a platform at this location, soil borings were taken by the well-known wireline technique. While experience in the Delta region led us to expect low soil strengths, the extent and depth of the very weak clays that were found in the boring program were unexpected. An immediate concern revolved around appropriate design approaches to withstand lateral and axial pile loadings. A second, and ultimately much more serious problem, was soon hypothesized; the soils were so weak that soil movement caused by slumping or sliding actions might take place. Thus, while the design proceeded, a program of research and field work to evaluate the probability of sea-floor movements was undertaken. The first public discussion of the potential problem was presented in 1970. Since that time, other investigators have studied the problem. The major conclusion of the initial engineering study and research was that waves in a major hurricane could cause sufficient bottom pressures to create soil instability. This situation, however, could only be developed in severe hurricanes occurring about once in a hundred years or greater, and would not occur under normal sea conditions or moderate storms. Accordingly, the decision was made to design the structure using the once-in-a-hundred-years wind and wave. Because of the very weak near-surface soils, the bottom of the structure was extended into the soil (see Fig. 2). This extension provided for increased stability during installation and reduced lateral deflections under wave loading. Hurricane Camille formed in the western Caribbean during the morning of Aug. 15, 1969. The eye of the storm, following the path shown in Fig. 1, crossed the Mississippi Gulf Coast on the evening of Aug. 17. Shell's South Pass 70 Platform B was destroyed in this storm, as was the Gulf Oil Co. South Pass 61 platform. Pass 61 platform. Investigation Program After Hurricane Camille, an intensive investigation was initiated to determine the cause of failure of the South Pass 70 Platform B. The investigation included above-water inspection of several adjacent platforms, the use of side-scan sonar to get a post-Camille picture of the South Pass 70 Platform B structure, a series of topographical surveys to compare with pre-camille conditions, several post-Camille soil borings to compare with pre-camille post-Camille soil borings to compare with pre-camille conditions, and a detailed diving and underwater television inspection of the fallen Platform B. Results and Interpretations Above-Water Inspection Seven major platforms in the general area were visited by a team of offshore-platform design engineers. Their main purpose was to ascertain the above-water damage at each site and to establish, where possible, the maximum wave crest reached on each platform. JPT P. 263

The influence of eye movements on a new type of apparent visual movement

When the sides of a contour triangle are sequentially presented, Ss report a sequential “flow” of brightness within the sides or a sequential “growth” of the sides. Modal report of this movement occurs in all three sides when the interside intervals are equal and 100 msec. Increasing the probability of contour scanning eye movements leads to an increase in this type of apparent visual movement.