We present new X-ray and optical spectroscopy of a Type 2 quasar candidate selected from a follow-up program of hard, optically-dim, serendipitous Chandra sources. The source is confirmed to be a Type 2 quasar at z = 0.536 with an intrinsic 2–10 keV luminosity L 2−10 = 5 × 10 44 h −2 0.7 erg s −1 , an absorbing column density N H = 8 × 10 23 cm −2 and a neutral Fe Kα line detected by XMM-Newton...

Double Boolean algebras are algebras (D,u,t, , ,⊥,>) of type (2, 2, 1, 1, 0, 0). They have been introduced to capture the equational theory of the algebra of protoconcepts. A filter (resp. an ideal) of a double Boolean algebra D is an upper set F (resp. down set I) closed under u (resp. t). A filter F is called primary if F 6= ∅ and for all x ∈ D we have x ∈ F or x ∈ F . In this note we prove t...

The entrainability of Lemna perpusilla CO(2) output by periodic 15 minute red (R) and far red (F) illuminations was tested in low nitrate medium. R every 8 hour, symbolized R/R/R, gives a flat output (no entrainment) as does F/F/F. However, R/-/- (R every 24 hour) entrains rapidly, and F/-/- does so as well, in a similar manner. The effects of R/R/- and F/F/- also resemble each other closely. E...

The problem of terminating a transmission line that consists of a set of coupled loop resonators to support the propagation of magneto-inductive waves is considered. Since the ideal terminating impedance is not easily realisable end-reflections are generally obtained from such a line. Techniques are developed to calculate the reflection coefficient from a line terminated with a finite number of...

We study sandpile models as closed systems, with the conserved energy density zeta playing the role of an external parameter. The critical energy density zeta(c) marks a nonequilibrium phase transition between active and absorbing states. Several fixed-energy sandpiles are studied in extensive simulations of stationary and transient properties, as well as the dynamics of roughening in an interf...

The Casimir force is one of the most accessible experimental consequences of vacuum fluctuations in the macroscopic world. It is the most significant force between neutral, non-magnetic objects at distances on the micrometer scale and below. For many experiments searching for novel short-range forces predicted by unification models, theoretical calculations of the Casimir force are crucial and ...

We show that the (2 × 2)-subpermanents of a generic matrix generate an ideal whose height, unmixedness, primary decomposition, the number and structure of the minimal components, resolutions, radical, integral closure and Gröbner bases all depend on the characteristic of the underlying subfield: if the characteristic of the subfield is two, this ideal is the determinantal ideal for which all of...

The possibility of using the self-induced transparency effect to passively modelock lasers has been discussed since the late 1960s, but has never been observed. It is proposed that quantum cascade lasers are the ideal tool to create this modelocking, due to their rapid recovery times and relatively long coherence times and because it is possible to interleave gain and absorbing layers. Converse...

Ideal photovoltaic cells would be black, absorbing all of the Sun’s radiation, whereas Nature’s machinery for solar energy harvesting— photosynthesis—looks green. Organic semiconductor devices, based on molecular building blocks, lie conceptionally between the extremes of inorganic and photosynthetic light harvesting. How can organic solar cells appear almost black if they are based on molecula...

Dispersal of the prolamellar body tubules into primary lamellar layers has been studied in leaves of dark-grown bean seedlings (Phaseolus vulgaris L.). Following complete photoconversion of protochlorophyllide the dispersal process can proceed in either light or darkness. The dispersal is reversibly inhibited in leaves at o °C. Above o °C the time course for the dispersal is temperature depende...