Tom Arnold

Electrical treatment of Lewis lung carcinoma in mice.

Direct electrical current of sufficient magnitude and duration can destroy tissue. This capability may be clinically useful in some cases involving inoperable metastatic lesions. In principle, a tumor could be treated with direct current administered via a percutaneous electrode insulated along its entire length except for the portion actually inserted into the tumor. An animal model was developed to study the effect of direct electrical current on tumor growth. The growth of implanted Lewis lung carcinoma in mice was inhibited following the administration of 2 mA for 1 hr, 1-3 treatments. The effect occurred in both small and large tumors. The results suggest that the electrical technique is potentially useful for treating some tumors.

Trade credit: a real option for bootstrapping small firms

This study uses a real options framework to predict small firm bootstrapping behavior with regard to trade credit discounts. Findings from a sample of 606 small firms suggest their managers place high value on the ability to adjust their decisions over time in response to firm-specific changes in (1) the uncertainty they face; and (2) the irreversibility of their decisions. The insights provided by this study can help scholars and small firm managers better understand how trade discount strategies should be analyzed with respect to other sources of bootstrap and long-term capital.

A Simplified Approach to Understanding the Kalman Filter Technique

The Kalman Filter is a time series estimation algorithm that is applied extensively in the field of engineering and recently (relative to engineering) in the field of finance and economics. However, presentations of the technique are somewhat intimidating despite the relative ease of generating the algorithm. This paper presents the Kalman Filter in a simplified manner and produces an example of an application of the algorithm in Excel. This scaled down version of the Kalman filter can be introduced in the (advanced) undergraduate classroom as well as the graduate classroom.

Are Cover Stories Effective Contrarian Indicators

Headlines from featured stories in Business Week,Fortune, and Forbes were collected for a 20-year period to determine whether positive stories are associated with superior future performance and negative stories are associated with inferior future performance for the featured company. “Superior” and “inferior” were determined in comparison with an index or another company in the same industry and of the same size. Statistical testing implied that positive stories generally indicate the end of superior performance and negative news generally indicates the end of poor performance. For this study, we identified feature stories from the cover headlines inBusiness Week, Fortune, andForbes for a 20-year period (1983–2002) to determine whether positive cover stories are associated with superior future performance and whether negative cover stories are associated with inferior future performance (where “superior” and “inferior” were defined in comparison with an index or with another company in the same industry and of the same size). The feature stories were categorized according to a five-point scale (1 = very positive, 2 = optimistic, 3 = neutral, 4 = pessimistic past but a better future predicted, and 5 = pessimistic with the potential for management turnover and/or litigation). Our statistical testing implies, as expected, that positive business magazine cover stories follow significantly positive performance and negative stories follow significantly negative performance. In both cases, however, the appearance of a company on a cover apparently signals the end of the extreme performance. We found for these companies going forward weak evidence that optimistic (Category 2) cover headlines are an indicator for momentum on a six-month horizon after publication. Negative cover headlines do not provide a good signal for momentum or contrarian strategies when performance is measured against an index or on a size/industry-adjusted basis, despite a popular belief that such cover headlines are a contrarian signal. Indeed, we found that companies that were the subject of negative cover headlines tended to have positive holding-period returns after publication of the magazine, but the positive returns were not abnormally positive when adjusted for an index or for size and industry. Consequently, if an investor is short the stock that is the subject of a negative cover story, the investor should consider covering the short position because the stock has hit “bottom.”

Diffuse ST segment depression from hypothermia

Hypothermia is known to cause specific electrocardiographic (EKG) changes such as Osborne waves and bradycardia. We report diffuse ST segment depression, an atypical EKG change, in a patient with a core temperature of 29.4°C (85°F). This patient had no previous cardiovascular pathology, and his EKG changes resolved gradually with aggressive warming. We also discuss the pathophysiology and clinical significance of ST depression in the general population and the typical EKG changes in hypothermia patients.

The Economics of Sallie Mae

The Student Loan Marketing Association, “Sallie Mae,” was formed by the federal government in 1972 to facilitate a secondary market for student loans. Now an independent entity, SLM Corporation is the largest lender and servicer of student loans in the U.S. As Sallie Mae made the transition into being a dominant player in all facets of the student loan industry (including student loan asset-backed securities, debt collection, and guarantor servicing), two economic theories have emerged. The “market for lemons” and “capture theory” theories serve as useful illustrations in understanding SLM’s evolution and future prospects.

Vascular Pedicle Width on Chest Radiograph as a Measure of Volume Overload: Meta-Analysis

Introduction Vascular pedicle width (VPW), a measurement obtained from a chest radiograph (CR), is thought to be an indicator of circulating blood volume. To date there are only a handful of studies that demonstrate a correlation between high VPW and volume overload, each utilizing different VPW values and CR techniques. Our objective was to determine a mean VPW measurement from erect and supine CRs and to determine whether VPW correlates with volume overload. Methods MEDLINE database, Web of Science, and the Cochrane Central Register of Controlled Trials were searched electronically for relevant articles. References from the original and review publications selected electronically were manually searched for additional relevant articles. Two investigators independently reviewed relevant articles for inclusion criteria and data extraction. Mean VPW measurements from both supine and erect CRs and their correlation with volume overload were calculated. Results Data from 8 studies with a total of 363 subjects were included, resulting in mean VPW measurements of 71 mm (95% confidence interval [CI] 64.9–77.3) and 62 mm (95% CI 49.3–75.1) for supine and erect CRs, respectively. The correlation coefficients for volume overload and VPW were 0.81 (95% CI 0.74–0.86) for both CR techniques and 0.81 (95% CI 0.72–0.87) for supine CR and 0.80 (95% CI 0.69–0.87) for erect CR, respectively. Conclusion There is a clinical and statistical correlation between VPW and volume overload. VPW may be used to evaluate the volume status of a patient regardless of the CR technique used.

Furniture as a Conduit for Credit

Securitization has transformed the global financial landscape, and in recent years accounts receivable securitization has become an increasingly popular means to accelerate cash flow. However, this particular style of securitization has encountered problems, which began well before the recent financial crisis. In 2000, Heilig-Meyers became the first company in which the senior notes of asset-backed securities suffered a principal loss. This article discusses the securitization of accounts receivable and its associated risks, using as an example the role of asset-backed securities in the Heilig-Meyers bankruptcy. In the case of Heilig-Meyers, selling furniture became secondary to issuing credit—a problem similar to the one that occurred in the real estate and mortgage markets.

Duration Measures for Corporate Project Valuation

Sensitivity analysis is a very common exercise performed with the forecasting of project cash flows. In this article, a duration-type measure is generated that provides a single number for the assessment of project cash flows relative to changes in the discount rate (or adjusted for changes in a particular cash flow model parameter). The calculation is no more difficult than the duration measures that already exist for bonds. Yet, the calculation provides valuable insight that many times is lost when performing sensitivity analysis. Further, at a minimum, the measure provides a gauge for the consequences of misspecifiying the discount rate for a project.

A Simple Model of Interest Rate Term Structure for the Classroom

Without much technical expertise, a yield curve model is presented that is very dynamic and can be easily programmed in Excel for classroom presentation or for assignments. By using the output of the model to have students find embedded rates within the yield curve, a discussion of how bond traders speculate on interest rates emerges very easily. Further, the model output can also be used for numerous exercises including the pricing of strips or for evaluating the positions of an entire bond portfolio. Within the exercises, the dynamic nature of the model can be exploited to provide sensitivity analysis.