Regulatory circuits have been defined in Neurospora c m s a within which multiple unlinked genes are controlled in a positive fashion by major regulatory genes. It has been suggested that repetitive DNA sequences situated adjacent to structural genes may serve as regulatory sites. Experiments are presented which examine the amount and organization of the repetitive sequences of Neurospora. The...

1 Arthropod natural enemies provide valuable pest suppression in agricultural landscapes. Natural enemy abundance and diversity within a given crop, in turn, have frequently been shown to be positively related to the amount of semi-natural habitat in the landscape. However, other aspects of landscape structure may also influence natural enemy communities and may be more amenable to management. ...

Nuclear RNA of high molecular weight, approximately 15 to 30 x 10(3) nucleotides long, isolated from rat ascites cells, has been shown previously to contain both middle repetitive and single-copy sequences. However, it was not known whether these sequences were located on separate molecules or whether they were interspersed within the same molecule. The present communication distinguishes betwe...

,The arrangement of repetitive and non-repetitive sequences was studied in the DNA of Xenopus. Labeled DNA sheared to various fragment lengths was reassociated to C,t 50 (SO’C, O-18 M-Na+) with excess 450 nucleotide fragments of unlabeled DNA, and binding of the labeled DNA to hydroxyapatite was measured. Repetitive sequences monitored in this way are present on about 45% of the 450 nucleotide ...

How to manage forest for biodiversity conservation is an ongoing debate. We argue that maximizing in managed landscapes requires a diversity of management regimes space and time. This will generate high levels habitat heterogeneity at landscape scale, which turn support various groups species. Based on concepts from ecology, we formulate five hypotheses how diversity, i.e. combining approaches ...

We study the spectrum in such a PT −symmetric square well (of a diameter L ≤ ∞) where the “strength of the non-Hermiticity” is controlled by the two parameters, viz., by an imaginary coupling ig and by the distance l < L of its onset from the origin. We solve this problem and confirm that the spectrum is discrete and real in a non-empty interval of g ≤ g0(l, L). Surprisingly, a specific distinc...