The Power-law Tail Exponent of Income Distributions

In this paper we tackle the problem of estimating the power-law tail exponent of income distributions by using the Hill's estimator. A subsample semi-parametric bootstrap procedure minimising the mean squared error is used to choose the power-law cutoff value optimally. This technique is applied to personal income data for Australia and Italy.Comment: Latex2e v1.6; 8 pages with 3 figures; in press (Physica A

Catalase-Containing Silica Particles as Ultrasound-Based Hydrogen Peroxide Sensors to Determine Infected From Noninfected Fluid Collections in Humans.

OBJECTIVE. Hydrogen peroxide (H2O2) plays a key role in neutrophil oxidative defense against infection. Catalase-containing silica nanoshells are nanoparticles that generate O2 microbubbles imaged with ultrasound in the presence of elevated H2O2. We aimed to determine whether ultrasound-detectable O2 microbubbles produced by catalase-containing silica nanoshells can determine whether fluid collections drained from patients are infected. SUBJECTS AND METHODS. During this HIPAA-compliant, institutional review board-approved study, 52 human fluid samples were collected from clinically required image-guided percutaneous drainage procedures. Catalase-containing silica nanoshells were added to the fluid samples during imaging in real time using a Sequoia-512 15L8-S linear transducer (Siemens Healthcare). Production of detectable microbubbles was graded subjectively as negative (noninfected) or positive (infected) with low, moderate, or high confidence by a single observer blinded to all clinical data. The truth standard was microbiology laboratory culture results. Performance characteristics including ROC curves were calculated. RESULTS. Microbubble detection to distinguish infected from noninfected fluids was 84% sensitive and 72% specific and offered negative and positive predictive values of 89% and 64%, respectively. The AUC was 0.79. Six of nine false-positive samples were peritoneal fluid collections that were all collected from patients with decompensated cirrhosis. CONCLUSION. The presence of elevated H2O2 indicated by microbubble formation in the presence of catalase-containing silica nanoshells is sensitive in distinguishing infected from noninfected fluids and offers a relatively high negative predictive value. False-positive cases may result from noninfectious oxidative stress. Catalase-containing silica nanoshells may constitute a novel point-of-care test performed at time of percutaneous drainage, potentially obviating placement of drains into otherwise sterile collections and minimizing risk of secondary infection or other complication

Simplified stock markets described by number operators

In this paper we continue our systematic analysis of the operatorial approach previously proposed in an economical context and we discuss a {\em mixed} toy model of a simplified stock market, i.e. a model in which the price of the shares is given as an input. We deduce the time evolution of the portfolio of the various traders of the market, as well as of other {\em observable} quantities. As in a previous paper, we solve the equations of motion by means of a {\em fixed point like} approximation.Comment: Rep. on Math. Phys., in pres

Application of multi-agent games to the prediction of financial time-series

We report on a technique based on multi-agent games which has potential use in the prediction of future movements of financial time-series. A third-party game is trained on a black-box time-series, and is then run into the future to extract next-step and multi-step predictions. In addition to the possibility of identifying profit opportunities, the technique may prove useful in the development of improved risk management strategies.Comment: Work presented at the NATO Workshop on Econophysics. Prague (Feb 2001). To appear in Physica

Veterinary Arsenicals

Feed medication and other forms of chemotherapy in our meat-producing animals have caused heated controversies. Some of this confusion is due to both a distortion of and a lack of information. Arsenicals are some of the oldest compounds whose use in agriculture has been questioned. An attempt will be made to trace the historical use of arsenicals and to discuss their metabolism and side effects from a veterinarian\u27s point of view

Topic Space: Rapid Prototyping a Mobile Augmented Reality Recommendation App

With funding from an Institute of Museum and Library Services (IMLS) Sparks! Ignition Grant, researchers from the University of Illinois Library designed and tested a mobile recommender app with augmented reality features. By embedding open source optical character recognition software into a “Topic Space” module, the augmented reality app can recognize call numbers on a book in the library and suggest relevant items that are not shelved nearby. Topic Space can also show users items that are normally shelved in the starting location but that are currently checked out. Using formative UX methods, grant staff shaped app interface and functionality through early user testing. This paper reports results of UX testing; a redesigned mobile interface, and provides considerations on the future development of personalized recommendation functionality.IMLS A0279Ope

Patterns in high-frequency FX data: Discovery of 12 empirical scaling laws

We have discovered 12 independent new empirical scaling laws in foreign exchange data-series that hold for close to three orders of magnitude and across 13 currency exchange rates. Our statistical analysis crucially depends on an event-based approach that measures the relationship between different types of events. The scaling laws give an accurate estimation of the length of the price-curve coastline, which turns out to be surprisingly long. The new laws substantially extend the catalogue of stylised facts and sharply constrain the space of possible theoretical explanations of the market mechanisms.Comment: 26 pages, 3 figures, 23 tables,2nd version (text made more concise and readable, algorithm pseudocode, results unchanged), 5-year datasets (USD-JPY, EUR-USD) provided at http://www.olsen.ch/more/datasets