Stacking classifiers for anti-spam filtering of e-mail

We evaluate empirically a scheme for combining classifiers, known as stacked generalization, in the context of anti-spam filtering, a novel cost-sensitive application of text categorization. Unsolicited commercial e-mail, or "spam", floods mailboxes, causing frustration, wasting bandwidth, and exposing minors to unsuitable content. Using a public corpus, we show that stacking can improve the efficiency of automatically induced anti-spam filters, and that such filters can be used in real-life applications

Comparing Regime-Switching Models In Time Series: Logistic Mixtures vs. Markov Switching

The purpose of this thesis is to review several related regime-switching time series models. Specifically, we use simulated data to compare models where the unobserved state vector follows a Markov process against an independent logistic mixture process. We apply these techniques to crude oil and heating oil futures prices using several explanatory variables to estimate the unobserved regimes. We find that crude oil is characterized by regime switching, where prices alternate between a high volatility state with low returns and significant mean reversion and a low volatility state with positive returns and some trending. The spread between one-month and three-month futures prices is an important determinant in the dynamics of crude oil prices

Propagator of a Charged Particle with a Spin in Uniform Magnetic and Perpendicular Electric Fields

We construct an explicit solution of the Cauchy initial value problem for the time-dependent Schroedinger equation for a charged particle with a spin moving in a uniform magnetic field and a perpendicular electric field varying with time. The corresponding Green function (propagator) is given in terms of elementary functions and certain integrals of the fields with a characteristic function, which should be found as an analytic or numerical solution of the equation of motion for the classical oscillator with a time-dependent frequency. We discuss a particular solution of a related nonlinear Schroedinger equation and some special and limiting cases are outlined.Comment: 17 pages, no figure

The Degradome database: mammalian proteases and diseases of proteolysis

The degradome is defined as the complete set of proteases present in an organism. The recent availability of whole genomic sequences from multiple organisms has led us to predict the contents of the degradomes of several mammalian species. To ensure the fidelity of these predictions, our methods have included manual curation of individual sequences and, when necessary, direct cloning and sequencing experiments. The results of these studies in human, chimpanzee, mouse and rat have been incorporated into the Degradome database, which can be accessed through a web interface at http://degradome.uniovi.es. The annotations about each individual protease can be retrieved by browsing catalytic classes and families or by searching specific terms. This web site also provides detailed information about genetic diseases of proteolysis, a growing field of great importance for multiple users. Finally, the user can find additional information about protease structures, protease inhibitors, ancillary domains of proteases and differences between mammalian degradomes

Percutaneous tracheostomy-beware of the thyroidea-ima artery

Percutaneous tracheostomy is a minimally invasive operation performed in patients, in order to provide an air passage through the windpipe. A rare cause of severe bleeding during such operation is the injury of the thyroidea-ima artery. This case report presents a patient with hemorrhage after thyroidea-ima injury during percutaneous dilatational tracheostomy. Surgeons should always be aware of such anatomic variation, in order to prevent urgent sternotomy

Efficient GF(p m ) Arithmetic Architectures for Cryptographic Applications

Recently, there has been a lot of interest on cryptographic applications based on fields OF(p"), for p > 2. This contribution presents OF(p TM) multipliers architectures, where p is odd. We present designs which trade area for performance based on the number of coefficients that the multiplier processes at one time. Families of irreducible polynomials are introduced to reduce the complexity of the modulo reduction operation and, thus, improved the efficiency of the multiplier. We, then, specialize to fields OF(3 TM) and provide the first cubing architecture pre- sented in the literature. We synthesize our architectures for the special case of OF(397) on the XCV1000-8-FG1156 and XC2VP20-7-FF1156 FPGAs and provide area/performance numbers and comparisons to previous OF(3 TM) and OF(2 TM) implementations. Finally, we provide tables of irreducible polynomials over OF(3) of degree m with 2 _< m _< 255

Cdc42 Regulates Apical Junction Formation in Human Bronchial Epithelial Cells through PAK4 and Par6B

A systematic screen of Cdc42 targets was carried out in human bronchial epithelial cells. Two kinases, PAK4 and Par6B/aPKC, were identified and are required for maturation of primordial junctions into apical junctions. PAK4 recruitment to primordial junctions is Cdc42-dependent, but maintenance at junctions during maturation is Par6B-dependent