Metallic foreign body deep in the prevertebral space after an endomyocardial biopsy: a case report

INTRODUCTION: Although inspirated or ingested foreign bodies constitute a common otolaryngologic emergency, the removal of a solitary retained foreign body from the neck has seldom been described in the literature. The ingestion of foreign bodies commonly results in perforated viscose or extraluminal migration to adjacent structures quite a long period of time after the fact. To the best of our knowledge, this is the first English language description of an endomyocardial biopsy complicated by a retained foreign body deep in the prevertebral space of the patient’s neck. We report such a case and share our experience in treating it. CASE PRESENTATION: A 68-year-old Asian man suffering right-sided heart failure underwent an endomyocardial biopsy via his right internal jugular vein. After undergoing the procedure, he was found to have retained a metallic cup tip which had become lodged in his neck. A surgeon then performed neck exploration and the foreign body was removed without adverse effect. CONCLUSIONS: Decision making as to whether to remove the foreign body or not remains controversial. However, the later incidence of adhesive fibrosis or, even worse, of a catastrophic abscess or adjacent vascular injury might occur if the foreign body was not removed. Early exploration is suggested, if the patient’s condition makes this feasible

Improvement of Static and Dynamic Properties of Soft Clay Using High Pressure Jet Grout

A proposed subway project is located in an area marked by a number of soft clay layers situated at depths from 60 ft to 100 ft below the ground surface. With unconfined compressive strength less than 0.6 tsf these natural soils are not strong enough to support on coming heavy loads and vibrations that the subway may be subject to in future. Hence the soil was trial grouted in-situ using high pressure jet grout technique to improve the engineering properties of the natural clay. A series of static and dynamic property tests were carried out on 18 samples selected from the site. Results show that the static and dynamic strength of the grouted clay improved significantly and the improvement depends on several parameters like confining pressure, cement content and water/cement ratio. The study provides a reasonable estimate of the extent of improvement (with respect to natural soil) and leads towards a better understanding of the static and dynamic properties of cement-treated clays and their behavior under various conditions

Behavioral Economics versus Traditional Economics: Are They Very Different?

Behavioral economics, notably developed by Daniel Kahneman, Amos Tversky and Richard Thaler, has found consistent and pervasive anomalies in common people’s daily behaviors. This paper has employed the concepts in traditional economics (e.g., choice, relative price, and opportunity cost) to analyze the anomalies found in behavioral economics. The results show that quite a few anomalies, such as preference reversal, isolation effect and sunk cost fallacy, do not exist. This is not to say that people always make rational choices. The findings of the paper conclude, however, that common people may not be as irrational as behavioral economists have suggested (in some situations, common people may act more like a rational economist)

On Using Risk-Neutral Probabilities to Price Assets

This paper has used the Arbitrage Theorem under binomial case to show that in a complete market with no transaction costs and no arbitrage, for any asset, the current spot price is a function of the risk-free interest rate, the future possible prices and their probabilities. These probabilities are the actual world probabilities, not the so-called risk-neutral probabilities. The paper also proves that for the levered firm, (i) under riskless debt, increasing the debt-equity ratio increases the variance of the rate of return on equity and has no effect on the rate of return on debt; and (ii) under risky debt, increasing the debt-equity ratio increases the variance of the rate of return on debt but does not affect the probability density function of the rate of return on equity. With the actual world probabilities, it can be shown that changes in the debt-equity ratio do not affect the expected rate of return on the equity of the levered firm. These findings refute the Modigliani-Miller second proposition that the expected rate of return on the equity of the levered firm increases in proportion to the debt-equity ratio. With the actual world probabilities, it is also found that increasing the variance of the underlying asset price may either increase or decrease the option prices

On Option Greeks and Corporate Finance

This paper has proposed new option Greeks and new upper and lower bounds for European and American options. It also shows that because of the put-call parity, the Greeks of put and call options are interconnected and should be shown simultaneously. In terms of the theory of the firm, it is found that both the Black-Scholes-Merton and the binomial option pricing models implicitly assume that maximizing the market value of the firm is not equivalent to maximizing the equityholders’ wealth. The binomial option pricing model implicitly assumes that further increasing (decreasing) the promised payment to debtholders affects neither the speed of decreasing (increasing) in the equity nor the speed of increasing (decreasing) in the insurance for the promised payment. The Black-Scholes-Merton option pricing model, on the other hand, implicitly assumes that further increasing (decreasing) in the promised payment to debtholders will: (1) decrease (increase) the speed of decreasing (increasing) in the equity though bounded by upper and lower bounds, and (2) increase (decrease) the speed of increasing (decreasing) in the insurance though bounded by upper and lower bounds. The paper also extends the put-call parity to include senior debt and convertible bond. It is found that when the promised payment to debtholders is approaching the market value of the firm and the risk-free interest rate is small, both the owner of the equity and the owner of the insurance will be more reluctant to liquidate the firm. The lower bound for the risky debt is: the promised payment to debtholders is greater or equal to the market value of the firm times one plus the risk-free interest rate

On Using Risk-Neutral Probabilities to Price Assets

This paper has used the Arbitrage Theorem under binomial case to show that in a complete market with no transaction costs and no arbitrage, for any asset, the current spot price is a function of the risk-free interest rate, the future possible prices and their probabilities. These probabilities are the actual world probabilities, not the so-called risk-neutral probabilities. The paper also proves that for the levered firm, (i) under riskless debt, increasing the debt-equity ratio increases the variance of the rate of return on equity and has no effect on the rate of return on debt; and (ii) under risky debt, increasing the debt-equity ratio increases the variance of the rate of return on debt but does not affect the probability density function of the rate of return on equity. With the actual world probabilities, it can be shown that changes in the debt-equity ratio do not affect the expected rate of return on the equity of the levered firm. These findings refute the Modigliani-Miller second proposition that the expected rate of return on the equity of the levered firm increases in proportion to the debt-equity ratio. With the actual world probabilities, it is also found that increasing the variance of the underlying asset price may either increase or decrease the option prices

Behavioral Economics versus Traditional Economics: Are They Very Different?

Behavioral economics, notably developed by Daniel Kahneman, Amos Tversky and Richard Thaler, has found consistent and pervasive anomalies in common people’s daily behaviors. This paper has employed the concepts in traditional economics (e.g., choice, relative price, and opportunity cost) to analyze the anomalies found in behavioral economics. The results show that quite a few anomalies, such as preference reversal, isolation effect and sunk cost fallacy, do not exist. This is not to say that people always make rational choices. The findings of the paper conclude, however, that common people may not be as irrational as behavioral economists have suggested (in some situations, common people may act more like a rational economist)

Growth rate regulation of lac operon expression in Escherichia coli is cyclic AMP dependent

AbstractIn contrast to the ribosomal RNA gene expression increasing with growth rate, transcription of the lac operon is downregulated by cell growth rate. In continuous culture, growth rate regulation of lac promoter was independent of carbon substrate used and its location on the chromosome. Since the lac operon is activated by cyclic adenosine monophosphate (cAMP), which decreases with increasing cell growth rate, expression of plac-lacZ reporter fusion was analyzed in cya mutant under various growth conditions. The results demonstrated that expression of plac-lacZ in cya mutant was both lower and growth rate independent. In addition, ppGpp (guanosine tetraphosphate) was not involved in the mechanism of growth rate regulation of the lac promoter. Thus, the results of this study indicate that cAMP mediates the growth rate-dependent regulation of lac operon expression in Escherichia coli

Earthquake-Induced Lateral Displacement of a Landfill

In the wake of stability failure of the Kettleman Hills Waste Repository on March 19, 1988, the stability of landfill mass in earthquake-prone areas has become an important issue in the community. Based on a proposed landfill site in the Memphis, Tennessee area, this paper studies behaviors of landfills under various landfill and earthquake conditions (height and slope angle of the landfill, average unit weight of the landfill refuse, and peak acceleration and time duration of bedrock motion) by calculating lateral displacements induced by a design earthquake. Results indicate that lateral displacement of a landfill is proportional to the slope angle of the landfill, peak acceleration and time duration of bedrock motion, and is inversely proportional to the average unit weight of the landfill refuse. The slope angle of a landfill and the peak acceleration of bedrock motion have significant influence on the lateral displacement of a landfill compared with landfill height, average unit weight of landfill refuse and time duration of bedrock motion. Results also indicate that some landfill heights should be avoided to diminish landfill resonance, and the maximum slope angle of a landfill under certain seismic conditions depends on the internal friction angle of the landfill refuse. In addition, the lateral displacements calculated from actual and pseudo-accelerations are compared and discussed