This article is a study of congruence conditions, modulo powers of two, on class number of real quadratic number fields Q(vu), for which d has at most thtee distinct prime divisors. Techniques used are those associated with Gaussian composition of binary quadratic forms. 1. Let hid) denote the class number of the quadratic field Qi\ß) and let h id) denote the number of classes of primitive bina...

The brain of the brown ghost knifefish, which uses electric fields to "see", processes electrical signals in a way that is similar to how our brains interpret visual and auditory signals.

The essential spectrum of multiparticle Brown– Ravenhall operators is characterized in terms of two–cluster decompositions for a wide class of external fields and interparticle interactions and for the systems with prescribed symmetries. 2000 Mathematics Subject Classification: 81V55, 81Q10

We construct a quartic threefold with L-rational singularities which has torsion in its middle homology group. This answers a question of Brown and Schnetz for all fields of characteristic zero.

The essential spectrum of multiparticle Brown– Ravenhall operators is characterized in terms of two–cluster decompositions for a wide class of external fields and interparticle interactions and for the systems with prescribed symmetries. 2000 Mathematics Subject Classification: 81V55, 81Q10

Brown et al. (2004) propose that ‘‘first principles of chemistry, physics, and biology’’ can be used to link the function of individual organisms to ecological processes. By arguing that metabolic rate controls ecological processes at all levels of organization, from the individual to the biosphere, they propose that a metabolic theory of ecology can be a powerful unifying principle. Because th...

Brown planthopper (Nilaparvata lugens Stål, Homoptera: Delphacidae) is economically important pest on rice that feed directly or serve as vectors of pathogenic microorganisms and viruses to crops, resulting in significant damage and yield losses for farmers. In recent decades, brown planthopper has become notorious due to the emergence of new, virulent populations that can overcome host resista...

We have measured the surface magnetic flux on four accreting young brown dwarfs and one non-accreting young very low-mass star utilizing high resolution spectra of absorption lines of the FeH molecule. A magnetic field of 1-2 kG had been proposed for one of the brown dwarfs, 2MASS J1207334−393254, because of its similarities to higher mass T Tauri stars as manifested in accretion and the presen...

We report on the first dedicated monitoring campaign of spectroscopic variability in young brown dwarfs. High-resolution optical spectra of six targets in nearby star-forming regions were obtained over 11 nights between 2005 JanuaryMarch on the Magellan 6.5m telescope. We find significant variability in Hα and a number of other emission lines related to accretion and outflow processes on a vari...