Consecutive Shocks Research Articles

Is Investor Misreaction Economically Significant? Evidence from Short- and Long-term S&P 500 Index Options

Several recent studies present evidence of investor misreaction in the options market. While the interpretation of their results is still controversial, we note that the important question of economic significance has not been fully addressed. We fill in this gap by formulating regression-based tests to identify misreaction and its duration and constructing trading strategies to exploit the empirical patterns of misreaction. Using regular S&P 500 index options and long-dated S&P 500 LEAPS, we find an underreaction that on average dissipates over the course of three trading days and an increasing misreaction that peaks after four consecutive daily variance shocks of the same sign. Option trading strategies based on these findings produce economically significant abnormal returns in the range of one to three percent per day. However, they are not profitable in the presence of transaction costs.

A mathematical model of the hsp70 regulation in the cell

A mathematical model of the regulation process of the heat shock protein hsp70 in the cell is presented. The model describes the damaging effect of elevated temperature on proteins; the interaction of free hsp70 with injured proteins and its chaperone role in nascent protein translation; the relation between the amount of free hsp70 and the formation of the activated trimer form of the heat shock factor protein (HSF) the binding of activated HSF with the heat shock elements on the DNA; the transcription of mRNA of hsp70 and the synthesis of hsp70. The reaction of the model to a temporal rise in temperature shows an initial decline and a subsequent sharp rise to an ultimately increased level of free hsp70 in the cell. The response of the model to both a single and two consecutive heat shocks appears to closely resemble experimental data on hsp70 synthesis. This general agreement demonstrates the structure of the model to be sound and suitable as a basis for further modelling the complex tolerance mechanism of the cell.

Conditions on the arrival process to obtain hnbue survival using a shock model

In this paper, we prove that the lifetime distribution of a device subject to random shocks with different interarrival mean times belongs to the HNBUE class without any assumption about the class of survival probabilities to the consecutive shocks. Following the model considered by Esary et al. (1973), we obtain conditions under which the survival function belongs to the HNBUE class which differ from those given by Klefsjo (1981b). From a practical point of view, these results simplify the study of failure times. We apply our results via a simulation study and obtain the lifetime distribution of a device when shocks arrive following a linear birth process.

Relation between shock-related myocardial injury and defibrillation efficacy of monophasic and biphasic shocks in a canine model.

Certain biphasic waveforms with specific time ratios of positive and negative components require less energy for successful defibrillation of the fibrillating ventricles than monophasic waveforms. However, if more efficient waveforms were also to be associated with more injurious effects on myocardial function, they might not provide a true biological advantage. This study investigates the relation between defibrillation efficacy and potential toxicity of monophasic and asymmetric, single capacitor, biphasic waveforms with equal durations of positive and negative components. The myocardial lactate extraction rate (LER) was used to measure the injurious effects on myocardial oxidative metabolism of two synchronized 35-J shocks in sinus rhythm. LER, mean arterial pressure (MAP) and, in a subset of experiments, cardiac output (CO) and coronary blood flow (CBF) were measured at baseline, 30 seconds, 60 seconds, 90 seconds, 150 seconds, 300 seconds, and 600 seconds after the shocks. In 12 dogs, three different waveforms (M 10: monophasic 10 milliseconds; BI 10: biphasic 10 milliseconds; BI 20: biphasic 20 milliseconds) were tested as series of two consecutive shocks (60 seconds apart) resulting in a total of 36 sets of data. At baseline, LER was 25 +/- 11%. After monophasic shocks, LER decreased significantly more than after biphasic shocks (LER at 150 seconds: M 10: -6 +/- 31% versus BI 10: 21 +/- 15% versus BI 20: 21 +/- 16%; M 10 versus BI 10 and M 10 versus BI 20, P < .05) and showed also a slower recovery (LER at 300 seconds: M 10: 1 +/- 24% versus BI 10: 20 +/- 11% versus BI 20: 20 +/- 15%; M 10 versus BI 10 and M 10 versus BI 20, P < .05). The maximal decrease in LER was 41 +/- 27% for M 10 compared with 18 +/- 15% for BI 10 and 15 +/- 11% for BI 20 (both, M 10 versus BI 10 and M 10 versus BI 20, P < .05). There was a similar decrease in CO and MAP, with the lowest MAP after monophasic shocks. The maximal decrease in MAP was significantly greater after M 10 compared with BI 20 (-29 +/- 15 mm Hg versus -13 +/- 11 mm Hg, P < .05). The defibrillation threshold was 18.6 +/- 8 J for M 10 compared with 11.5 +/- 4.0 J for BI 10 (P < .05) and 15.0 +/- 6.1 J for BI 20, respectively (P = NS). Our results suggest that these specific biphasic waveforms are associated with less injurious effects on myocardial oxidative metabolism and hemodynamic performance. Given their higher defibrillation efficacy as well, biphasic waveforms may provide important long-term benefits in patients receiving frequent shocks from implantable cardioverter-defibrillators.

A few electroconvulsive shocks produce more reliable effects of firing rate in lateral septal neurons than repetitive treatment in the rat.

Electroconvulsive shock is a common treatment used in depression, especially in cases in which suicide constitutes a risk. The recommendation for its use varies from one place to another, but there is an empirical agreement to avoid daily treatment or several treatments on the same day. The present study explored the actions of electroconvulsive shock in lateral septal firing rate in rats. The first or second once-a-day electroconvulsive shock produced a maximal increase in firing rate; however, effects vanished as treatment was repeated. Three consecutive electroconvulsive shocks on the same day also produced fewer changes in firing rate than once-a-day treatment. These results are likely to be related to clinical recommendations to avoid serial-repetitive treatment, and suggest that some resting time is required in treatment to achieve long-lasting changes in neuronal activity.

Automatic implantable cardioverter/defibrillator discharges and acute myocardial injury.

Multiple defibrillations by the automatic implantable cardioverter/defibrillator (AICD) have been reported to result in localized epicardial damage. No data exist, however, regarding whether this damage can be detected in the clinical setting or whether it interferes with the detection of true myocardial infarction. Forty-nine patients who received defibrillations by patch electrodes were studied prospectively. We attempted to document the presence of myocardial injury with the following three commonly used modalities for the detection of myocardial infarction: serial electrocardiographic changes, serial creatine phosphokinase (CPK) and CPK-MB release, and technetium 99m pyrophosphate scanning. Fifteen patients received defibrillations by AICD patches at the time of AICD generator replacement. Nine patients received defibrillations at the time of new AICD lead placement. The average total energy delivered was 85 +/- 29 J. None of these patients had detectable myocardial injury. Ten patients had defibrillations by the AICD patches at the time of bypass operation. One patient in this group developed acute myocardial infarction in the inferior wall after posterior descending coronary bypass operation, as detected by electrocardiogram, 99mTc pyrophosphate scanning, and CPK-MB analysis. Fifteen patients were evaluated for spontaneous AICD discharges. Thirteen had a maximum of five consecutive shocks, and cumulative energy delivered was not greater than 330 J. None of these patients had detectable injury. Two patients had CPK-MB release of 15.3% and 7.5%, respectively. One of these patients had a positive 99mTc pyrophosphate scan. These two patients received 12 and 17 rapid and consecutive AICD discharges, respectively, with cumulative delivered energy of 360 and 510 J, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

The response of manganin gauges to multiple-shock loading

The response of piezoresistance stress gauges to multiple-shock loading is discussed in terms of the elastoplastic model for their dynamic response. It is argued that their response to a second (or third) shock wave should not depend on previous shocks and should only depend on the amplitude of these consecutive shocks. In order to substantiate these arguments we performed double- and triple-impact experiments in which the impactors were composed of two (or three) metallic disks separated by 0.2-mm gaps. Symmetric experiments in which the shock waves were of equal amplitude resulted in an equal response of the gauge for each shock. Another type of impactor, with thin aluminum disks separated by 0.2 mm from thicker copper disks, resulted in higher second shocks. The response of the gauges to these higher shocks were equal to those obtained by single shocks with the same amplitudes.

The Characterization of Human Transmyocardial Impedance during Implantation of the Automatic Internal Cardioverter Defibrillator

We set out to determine in a prospective fashion the characteristics of energy delivery related to defibrillation in a population of patients receiving the AICD. Specifically, we examined the characteristics of the delivered current, transmyocardial voltage, and transmyocardial impedance. Secondly, we determined the relationship between the energy delivered, the impedance encountered and the defibrillation threshold. Since the AICD will deliver a succession of shocks if the initial shock does not cardiovert, the effects of consecutive shocks at different energy levels on the transmyocardial impedance were also assessed.

The choice of the energy level for shock destruction of material

The authors describe a study to obtain a detailed evaluation of the potential of the method of shock destruction with a view to its possible applications for the design of shock-based working elements for certain types of mining and construction machines. Two loading schemes were investigated in the study of shock destruction of materials: the first involves the destruction of finite specimens such as non-standard lumps of rocks, plates, and block materials, and the second is typical for the engineering processes separating a layer of material in excavation and mining. It is shown that the experimental relations for certain parameters of the shock process, expressed as a function of a sequence of consecutive shocks against a wedge indenter, indicate drastic variations of their values from one stroke to another. The authors adopted a pneumatic principle for shock-action devices which is described here. The experimental data were used to design a series of shock devices with unit stroke energies ranging from 1000 to 2500 J.

Dynorphin- and enkephalin-like immunoreactivity is altered in limbic- basal ganglia regions of rat brain after repeated electroconvulsive shock

In an attempt to determine whether the opioid peptides derived from prodynorphin participate in the effects of electroconvulsive shock (ECS), we used radioimmunoassay and immunocytochemistry to measure dynorphin-like immunoreactivity (DN-LI) in various rat brain regions after repeated ECS treatments. Ten daily ECSs caused a significant increase in dynorphin A (1-8)-LI in most limbic-basal ganglia structures, including hypothalamus (50%), striatum (30%), and septum (30%). No significant change was found in the frontal cortex or the neurointermediate lobe of the pituitary. In contrast, 10 ECS treatments depleted DN-LI in hippocampal mossy fibers by 64%. A detailed time-course study revealed that a single shock caused a small but significant increase in hippocampal DN-LI, whereas three consecutive shocks depleted DN-LI by 30%. The maximal decrease in DN-LI was reached after six daily ECSs. The level of DN-LI in the hippocampus partly recovered, but remained lower than the control value 4, 7, and 14 d after the cessation of six daily ECSs (50, 77, and 83% of control value, respectively). In contrast with the ECS-induced depletion of hippocampal dynorphin, 10 daily ECSs caused a significant increase (40%) in (Met5)-enkephalin-LI in the hippocampus, as well as in other limbic-basal ganglia structures. Immunocytochemistry revealed that enkephalin-LI was increased in the perforant pathway, which is presynaptic to the dynorphin-containing mossy fiber pathway in the hippocampus. These observations suggest that different mechanisms may regulate these two opioid peptide systems in the hippocampus.(ABSTRACT TRUNCATED AT 250 WORDS)

Repeated electroconvulsive shock downregulates the opioid receptors in rat brain

Ten consecutive daily electroconvulsive shocks (ECSs), which produce maximal tonic and clonic convulsions, caused reductions of μ- and θ-opioid receptor binding in the hypothalamus, hippocampus and caudate nucleus, but not in the frontal cortex and brainstem. These changes of opioid receptor binding were not observed in rats receiving a single ECS. Scatchard analysis revealed that ECS-induced reduction of μ- and δ-receptor binding was due to a decrease in the binding sites but not to a change in the binding affinity. Time course studies showed that 7 days after the end of 10 consecutive daily ECSs, both μ- and δ-receptor binding remained lower than those of sham controls. However, the effects of ECS on the opioid receptor binding disappeared in 2–3 weeks. These observations are consistent with the hypothesis that ECS treatments increase the release of opioid peptides in certain brain regions which in turn down-regulate the opioid receptors.

Electrophysiologic changes induced by external transthoracic countershock

The purpose of this study was to characterize the electrophysiological effects of suprathreshold transthoracic shocks. Dogs were anesthetized and two consecutive shocks (10 joules/gk) were applied one minute apart. Ventricular extrasystoles were observed in six of the 11 dogs tested, A-V block in three, ventricular tachycardia in three, and asystole in one. Forty eight hours later the hearts were removed. Conventional electrophysiological techniques revealed the following: 1) injured cells had loss of resting potential, triangularization of the action potential and depressed upstrokes; 2) the functional refractory period was shortened, with an increase in time dependence; 3) action potential alternans; 4) discrete areas of marked depression of conduction; 5) re-excitation with premature stimulation and 6) histological evidence of sub-epicardial injury. These studies suggest that the application of suprathreshold shocks may induce electrophysiological changes potentially inducing tachyarrhythmias.

Opiate-like electroencephalographic and behavioral effects of electroconvulsive shock in rats

Rats were studies (a) after a single transauricular electroshock (acute ECS) and (b) following 10 consecutive once-daily shocks (chronic ECS). ECS produced a generalized convulsion marked by a polyspike EEG seizure. The seizure was followed by a period of postictal depression (PID) characterized by EEG high-voltage synchrony, EMG quietening, and an associated stuporous behavior in the rat. Acute ECS produced a maximal increase of 33±8 (S.E.) percent above control in the EEG voltage output during postictus, with the PID lasting 2 680±658 sec. Chronic ECS resulted in a significant enhancement of these acute responses. Pretreating rats with naloxone (0.3–10 mg/kg, s.c.) antagonized the postictal effects of acute ECS, but not of chronic ECS. These naloxone-sensitive postictal EEG and behavioral changes appear to reflect a release of endogenous opioid peptides during ictus, a finding consistent with the hypothesis that electroshock activates opioid systems.

Suspected periodicities of earthquakes in Sweden

Diurnal and annual periodicities of earthquakes in Sweden are investigated on the basis of a recent instrumental catalogue for the interval from 1951 to 1976. Even though some periods may be suggested, none of them proves to be statistically significant. Likewise, periods earlier supposed from macroseismic data are not confirmed and must therefore also be dismissed. The frequency of occurrence of intervals between consecutive shocks suggests that Swedish earthquakes are randomly distributed in time.

Time and magnitude relations for three microaftershock series near Hollister, California

Abstract Three series of aftershocks occurred in the region near Hollister, less than 15 km from the San Andreas Geophysical Observatory in 1968, 1970, and 1971 following shocks of magnitudes 2.3, 3.2, and 4.0, respectively. The high-gain system operating at SAO permitted a full study of these series for events as small as magnitude -0.7. The distribution of time intervals between consecutive shocks and magnitudes show certain definite differences in the time, space, and magnitude structure of the three sequences. The 1968 and 1970 series are highly concentrated in time and originate from quite small source volumes. Both correspond to the mainshock-after-shock type with high values of b (1.1 and 0.91). The 1971 series located in the Bear Valley area about 15 km south of the other two belongs to the swarm type with a low value of b (0.41). The situation suggests different physical conditions in two neighboring areas of the same fault with less homogeneous material and higher stresses acting at the area of the 1971 series. Variations in the b value with time for an area of 2500 km2 around SAO can be interpreted as due to migration of seismic sources from one area to another, or definite changes in rock properties with time.

Impaired free-operant avoidance behavior following ventromedial hypothalamic lesions in rats

Under each of 3 shock intensities, ventromedial hypothalamic lesioned rats emitted fewer responses and received more shocks than control animals in a lever-pressing free-operant avoidance paradigm. While the performance of the control animals improved across 10 days of testing and within each session, the between- and within-session performance of the lesioned rats, after improving moderately during the first few days of testing, deteriorated as training progressed. Although the response rates of the lesioned animals were relatively unrelated to the different current levels, their shock rates varied inversely with intensity. This resulted from an increase in the frequency of long interresponse times and a reduction in the number of consecutive shocks. Preoperative training substantially improved the avoidance behavior of lesioned animals, but their postoperative performance was nevertheless inferior to their preoperative levels.

Statistical analysis of microearthquake activity near San Andreas geophysical observatory, Hollister, California

Abstract Microearthquake activity during the 4-year interval 1968 to 1971 in a region of 25 km radius, centered on the San Andreas fault near Hollister, has been monitored by means of high-gain high-frequency seismographs which allow detection of events as small as magnitude zero within the region. The distribution of the 4764 microearthquakes shows a high degree of clustering. The series of time intervals between consecutive shocks can be described approximately by a gamma distribution whose shape parameters for different samples change from 0.3 to 0.8. The exponential probability plots of the {Δti} series for 265 larger regional earthquakes over 10 years result in a constant value of the hazard function except for small values of time where the hazard is higher. The variance-time and intensity functions show a varying degree of interdependence between events for each year and a long-term dependence up to 80 days for the period 1968-1971. The time scale of clustering has been estimated. Inferences based on short-term microearthquake studies may be grossly misleading.

Paralysis following “freezing” to a wire

HOW LONG will you be “frozen” to an energized wire after the circuit is interrupted? Failure to utilize the correct answer in design might result in your being a victim the next time you inadvertently grasp an electric fence. Information on the probable length of time it takes a person to release his grasp of a wire after being subjected to currents above his “let-go” limit is important in establishing the minimum allowable “off” period for electric fences and is of concern to the ASA (American Standards Association) Sectional Committee on Electric Fences, C69. Death is to be an expected result should a victim suffer a sufficient number of shocks due to his inability to release his grasp of an electrified fence during the “off” period between consecutive shocks.