The Tech Buzz Game [stock market prediction]

Prediction markets, also known as information or decision markets, are designed to forecast future events or trends. Internet-based prediction markets can easily aggregate the insights of an unlimited number of potentially knowledgeable people asynchronously. The Tech Buzz Game - a joint venture between Yahoo! Research Labs and O'Reilly Media - is a fantasy prediction market launched in March 2005 at the O'Reilly Emerging Technology (ETech) Conference. The game consists of multiple sub-markets that pit a handful of rival technologies, each represented by a stock, against one another. The game's object is to anticipate future search buzz and buy and sell stocks accordingly. Thus, a player who believes BitTorrent stock is undervalued might buy shares, while a player who thinks BitTorrent is overpriced might sell the stock or instead purchase shares in a competing peer-to-peer technology. The Tech Buzz Game serves two key research-oriented goals. One is to evaluate the power of prediction markets to forecast high-tech trends. The other goal of the Tech Buzz Game is to field test the dynamic pari-mutuel market, a Yahoo! Research Labs trading mechanism designed to price and allocate shares.     

Not just another self-consistent magnetic recording model

A self-consistent magnetic recording modeling method is presented which has proven useful in recording channel design on thin media. Improvements in the magnetic model and in the mathematical treatment stabilize the iterative process and reduce computer storage requirements. Major and minor media loops are fitted to quickly computable bipolynomials. Mathematical improvements include using a strong band diagonal demagnetization matrix, analytic integration with quadratic magnetization fitting, and Newton-Raphson iteration, which gives rapid convergence without underrelaxation. Quantitative predictions of timing errors in 16-bit modified frequency modulation (MFM) data patterns on a 350-bit/mm, 20-track/mm disk memory are presented, as well as playback amplitudes and saturation currents. Predictions can also be compared with experimental read/write data to determine system parameters. Two examples are given: the inference of the head efficiency and of the effective high-frequency medium squareness.     

Commonality and variability in software engineering

The article describes how to perform domain engineering by identifying the commonalities and variabilities within a family of products. Through interesting examples dealing with reuse libraries, design patterns, and programming language design, the authors suggest a systematic scope, commonalities, and variabilities approach to formal analysis. Their SCV analysis has been an integral part of the FAST (Family-oriented Abstraction, Specification, and Translation) technology applied to over 25 domains at Lucent Technologies     

End product specificity of triacylglycerol lipases from intestine,fat body,muscle and haemolymph of the American cockroach,Periplaneta americana L.

The triacylglycerol-hydrolyzing capacity of tissue homogenates has been investigated for midgut, fat body, thoracic musculature and haemolymph of the American cockroach,Periplaneta americana. The greatest lipolytic activity was demonstrated in midgut homogenates with decreasing levels of activity present in fat body, muscle and haemolymph. Comparison of the lipolytic products resulting from triacylglycerol hydrolysis indicates that midgut homogenates effect the production ofsn-2-monoacylglycerols and free fatty acids, whereas the other tissues that were examined favor the accumulation of diacylglycerols. Stereospecific analysis of the diacylglycerol products of triacylglycerol hydrolysis demonstrated that the lipolytic activities of midgut and muscle homogenates result in the production of a racemic mixture of thesn-1,2-andsn-2,3-enantiomers, but the fat body and haemolymph show a preference for the accumulation of thesn-1,2-isomer.     

Transferring information from one experiment to another

This paper presents a rational method (based on Bayes' Theorem) for transferring information on parameter values from one experiment to another, in situations where the mathematical models for the two experiments share some parameters in common. The uncertainty in the estimates of the parameters, which reflects the experimental error in the initial experiment, is properly transferred as well. The use of the method is demonstrated by applying it to a fairly complicated system, typical in chemical reaction engineering, in which the kinetic parameters in a model for the hydrogenolysis of butane reaction were estimated using data obtained from a bench-scale, integral packed-bed reactor. These parameter estimates were then transferred to a model for a fluidized bed reactor in which the same chemical reaction occurred. Using the fluidized bed data they were updated and two additional parameters in the fluidized bed model were also estimated. This procedure allows a more realistic estimate of the uncertainty in all parameter values in the model for the fluidized bed reactor.     

Differences in psychosocial and health correlates of major and minor depression in medically ill older adults

OBJECTIVES: To compare the differences in correlates of different levels of depression in medically ill hospitalized older adults. DESIGN, SETTING, AND PARTICIPANTS: A consecutive series of 542 patients aged 60 or older admitted to the medical inpatient services of Duke Hospital underwent a structured psychiatric evaluation administered by a psychiatrist. MEASUREMENT: A wide range of demographic, social, psychiatric, and physical health data were collected, and associations with major and minor depression were assessed. RESULTS: Compared with patients without depression, those with major depression were more likely to have a history of prior episodes of depression, higher dysfunctional attitude scores, greater overall severity of medical illness, cognitive impairment, and symptoms of pain or other somatic complaints. Specific medical diagnosis was less important a predictor of major depression than overall severity of medical illness. Compared with patients without depression, those with minor depression were more likely to report non-health-related stressors during the year before hospital admission, have a diagnosis of immune system disorder, and have greater severity of medical illness. When major and minor depression were compared directly, on the other hand, no significant differences were observed except for history of depression, and that relationship was weak and present only when the etiologic approach to diagnosis was used. CONCLUSION: During hospital admission, certain psychosocial, psychiatric, and physical health characteristics of older medical patients place them at high risk for different levels of depression. Patients with major and minor depression resemble each other more than they do patients without depression. These findings may help clinicians better understand the causes of different types of depression in this setting and lead to improved diagnosis and treatment.     

Heat shock activates c-Src tyrosine kinases and phosphatidylinositol 3-kinase in NIH3T3 fibroblasts

There is increasing evidence that cellular responses to stress are in part regulated by protein kinases, although specific mechanisms are not well defined. The purpose of these experiments was to investigate potential upstream signaling events activated during heat shock in NIH3T3 fibroblasts. Experiments were designed to ask whether heat shock activates p60 c-Src tyrosine kinase or phosphatidylinositol 3-kinase (PI 3-kinase). Using in vitro protein kinase activity assays, it was demonstrated that heat shock stimulates c-Src and PI 3-kinase activity in a time-dependent manner. Also, there was increased PI 3-kinase activity in anti-phosphotyrosine and anti-c-Src immunoprecipitated immunocomplexes from heated cells. Heat shock activated mitogen-activated protein kinase (MAPK) and p70 S6 kinase (S6K) in these cells. The role of PI 3-kinase in regulating heat shock activation of MAPK and p70 S6K was investigated using wortmannin, a specific pharmacological inhibitor of PI 3-kinase. The results demonstrated that wortmannin inhibited heat shock activation of p70 S6K but only partially inhibited heat activation of MAPK. A dominant negative Raf mutant inhibited activation of MAPK by heat shock but did not inhibit heat shock stimulation of p70 S6K. Genistein, a tyrosine kinase inhibitor, and suramin, a growth factor receptor inhibitor, both inhibited heat shock stimulation of MAPK activity and tyrosine phosphorylation of MAPK. Furthermore, a selective epidermal growth factor receptor (EGFR) inhibitor, tryphostin AG1478, and a dominant negative EGFR mutant also inhibited heat shock activation of MAPK. Heat shock induced EGFR phosphorylation. These results suggest that early upstream signaling events in response to heat stress may involve activation of PI 3-kinase and tyrosine kinases, such as c-Src, and a growth factor receptor, such as EGFR; activation of important downstream pathways, such as MAPK and p70 S6K, occur by divergent signaling mechanisms similar to growth factor stimulation.     

Effects of changes in intraocular pressure on human ocular haemodynamics

PURPOSE: Myogenic autoregulation is the ability of a vascular bed to maintain blood flow despite changes in perfusion pressure. Ocular perfusion pressure is defined as the difference between ocular arterial pressure and ocular venous pressure, the latter dependent on intraocular pressure (IOP). The aim of the present study was to investigate the effect of moderate increases in IOP on ocular haemodynamics. METHODS: Changes in IOP (+ 10 mmHg, +20 mmHg) were induced by a suction cup in 10 healthy subjects. Ocular fundus pulsations in the macula and the optic disc were measured by laser interferometry; blood flow velocities in the central retinal artery (CRA) and in the ophthalmic artery (OA) were measured by Doppler sonography. RESULTS: Changes in IOP caused a significant reduction in fundus pulsations, which was more pronounced in the macula (at +10 mmHg: -9 +/- 2%, p < 0.01; at +20 mmHg: -19 +/- 3%, p < 0.001) than in the optic disc (at +10 mmHg: -5 +/- 2% (ns); at +20 mmHg: -9 +/- 3%, p < 0.01). Mean flow velocity in the CRA was reduced by -5 +/- 3% at +10 mmHg (ns) and by -14 +/- 5% at +20 mmHg (p < 0.005), resistive index was increased by +4 +/- 1% at +10 mmHg (p < 0.05) and by +6 +/- 2% at +20 mmHg (p < 0.01). In contrast, a rise in IOP did not affect blood flow parameters in the OA. CONCLUSIONS: Our results from fundus pulsation measurements indicate that choroidal blood flow decreases when IOP is increased. The Doppler sonographic findings in the CRA indicate reduced blood flow velocity in this artery during raised IOP.     

Correlation between ear canal resonance and tympanic membrane impedance in relation to age and body mass and postmortem changes

The human temporal bone preparation is an acknowledged model for research of the physical processes affecting the outer ear canal and eardrum. Changes affecting the oscillation and resonance behavior of the tympanic membrane and ear canal between death and temporal bone preparation presently exist in only a few studies. Since the influence of age and physique, as well as the width of ear canal on the ear canal resonance may be important, we prepared two separate studies to analyze these questions. The goal of our first test series involved children and was devised to determine if changes in the outer auditory canal resonances differed according to age. In so doing, canal resonance was recorded with a real ear measurement system. Further, we recorded middle ear pressure, impedance of the tympanic membrane, ear canal volume, height, weight and surface of the body, head and ear size. We found a significant decrease in the resonance frequency of the outer ear which was age-dependent and was 2.75 kHz in the 7-year-old child. In a separate study we wanted to know if results found in the postmortem temporal bone reflected in vivo relationships. A tympanometer and real ear measurement system was used to test the resonance behavior of the auditory canal as well as the vibration of the eardrum in dependence on temperature and the time after death for 9 h. We then proved the absence of significant changes in the auditory canal and eardrum oscillation in this time period before possible postmortem changes occurred. Our findings show that the method of bone preservation after its preparation is decisive for the validity of measurements in the isolated human temporal bone.