Axial Anomaly in Noncommutative QED on R^4

The axial anomaly of the noncommutative U(1) gauge theory is calculated by a number of methods and compared with the commutative one. It is found to be given by the corresponding Chern class.Comment: LaTeX, axodraw.sty; v2: typos are fixed; v3: version to appear in Int. J. Mod. Phys. A. (2001

Comparing Web-Based Content Delivery and Instructor-Led Learning in a Telecommunications Course

This study compares the achievement of students enrolled in two sections of an undergraduate telecommunications course. One class was conducted in an instructor-led classroom and the other utilized a web-based content delivery method. Students were unaware of the difference in delivery methods at the time of registration. Identical pre- and post-tests were administered to the students and a statistical analysis was performed. While in a practical sense, the instructor-led classroom generated much higher average performance, the difference between the two methods was not statistically significant

Short-course treatment in neurobrucellosis: A study in Iran

Neurobrucellosis is a rare neurological complication of brucellosis. This report describes 19 patients of neurobrucellosis and they accounted for 8% of all cases of brucellosis admitted to Shiraz University Hospitals over a period of eight years. Headache, fever, fatigue, drowsiness and neck stiffness were the common clinical features. Cerebrospinal fluid (CSF) showed pleocytosis in 100%, elevated protein levels in 89% and low glucose level in 47% of the patients. All the patients improved with specific antibiotic treatment. Of the 19 patients, 10 (52.5%) patients received treatment for 8 to 28 weeks. Duration of antibiotic treatment was: 8-14 weeks in 8 (42%) patients; 24-28 weeks in 2 (10.5%) patients; 6 months in 7 (37%) patients; 12 months in 1 (5.3%) patient; and 18 months in 1 (5.3%) patient. Clinicians in endemic areas should consider the likelihood of neurobrucellosis in patients with unexplained neurological and psychiatric symptoms

A Self-Paced Two-State Mental Task-Based Brain-Computer Interface with Few EEG Channels

A self-paced brain-computer interface (BCI) system that is activated by mental tasks is introduced. The BCI’s output has two operational states, the active state and the inactive state, and is activated by designated mental tasks performed by the user. The BCI could be operated using several EEG brain electrodes (channels) or only few (i.e., five or seven channels) at a small loss in performance. The performance is evaluated on a dataset we have collected from four subjects while performing one of the four different mental tasks. The dataset contains the signals of 29 EEG electrodes distributed over the scalp. The five and seven highly discriminatory channels are selected using two different methods proposed in the paper. The signal processing structure of the interface is computationally simple. The features used are the scalar autoregressive coefficients. Classification is based on the quadratic discriminant analysis. Model selection and testing procedures are accomplished via cross-validation. The results are highly promising in terms of the rates of false and true positives. The false-positive rates reach zero, while the true-positive rates are sufficiently high, i.e., 54.60 and 59.98% for the 5-channel and 7-channel systems, respectively

Turbulent Origin of the Galactic-Center Magnetic Field: Nonthermal Radio Filaments

A great deal of study has been carried out over the last twenty years on the origin of the magnetic activity in the Galactic center. One of the most popular hypotheses assumes milli-Gauss magnetic field with poloidal geometry, pervading the inner few hundred parsecs of the Galactic-center region. However, there is a growing observational evidence for the large-scale distribution of a much weaker field of B \lesssim 10 micro G in this region. Here, we propose that the Galactic-center magnetic field originates from turbulent activity that is known to be extreme in the central hundred parsecs. In this picture the spatial distribution of the magnetic field energy is highly intermittent, and the regions of strong field have filamentary structures. We propose that the observed nonthermal radio filaments appear in (or, possibly, may be identified with) such strongly magnetized regions. At the same time, the large-scale diffuse magnetic field is weak. Both results of our model can explain the magnetic field measurements of the the Galactic-center region. In addition, we discuss the role of ionized outflow from stellar clusters in producing the long magnetized filaments perpendicular to the Galactic plane.Comment: 11 pages, accepted to ApJ Letter