Magnetizations and magnetic moments of free cobalt clusters Co(N) (12 < N < 200) in a cryogenic (25 K < or = T < or = 100 K) molecular beam were determined from Stern-Gerlach deflections. All clusters preferentially deflect in the direction of the increasing field and the average magnetization resembles the Langevin function for all cluster sizes even at low temperatures. We demonstrate in the ...

HE preceding paper of this series (ROBERTSON 1959) and the present one Tdeal with different parts of a single study of the relations between cell size and number in the wing of Drosophila melanogaster. The reasons for examining this problem together with details of procedure and statistical analysis are given in the earlier paper but a brief resunik will help the reader to appreciate what follo...

The stereotyped positioning of sensory bristles in Drosophila has been shown to result from complex spatiotemporal regulation of the proneural achaete-scute genes, that relies on an array of cis-regulatory elements and spatially restricted transcriptional activators such as Pannier. Other species of derived schizophoran Diptera have equally stereotyped, but different, bristle patterns. Divergen...

Our ability to predict long-term responses to artificial and natural selection, and understand the mechanisms by which naturally occurring variation for quantitative traits is maintained, depends on detailed knowledge of the properties of spontaneous polygenic mutations, including the quantitative trait loci (QTL) at which mutations occur, mutation rates, and mutational effects. These parameter...

A semi-lethal, sterile allele of the smooth locus (2-91.5), sm3, was discovered in an artificial selection line for low abdominal bristle number that had been started from a P-M dysgenic cross. The fitness effects and extremely low bristle number phenotype of the allele could not be separated by recombination from a P-element insertion at cytological location 56E, and precise excision of the P-...

The endocytosis of tracer particles by sinusoidal endothelial cells was studied in the bone marrow and liver of the rabbit and in the bone marrow of the rat after intravenous injection. The tracer particles used included carbon particles and polystyrene particles of different sizes ranging from 0.11 to 5.7 micron in diameter. The sinusoidal endothelial cells of the rabbit liver and rat bone mar...

To determine the ability of the P-M hybrid dysgenesis system of Drosophila melanogaster to generate mutations affecting quantitative traits, X chromosome lines were constructed in which replicates of isogenic M and P strain X chromosomes were exposed to a dysgenic cross, a nondysgenic cross, or a control cross, and recovered in common autosomal backgrounds. Mutational heritabilities of abdomina...

Stable localization of the signaling complex is essential for the robust morphogenesis of polarized cells. Cell elongation involves molecular signaling centers that coordinately regulate intracellular transport and cytoskeletal structures. In Drosophila bristle elongation, the protein kinase IKKε is activated at the distal tip of the growing bristle and regulates the shuttling movement of recyc...

The wing blade of Drosophila melanogaster is composed of dorsal and ventral surfaces covered with hairs and rows of morphologically distinct bristles round the margin. The mutant shaggy causes a complete transformation of hairs into bristles over the entire wing surfaces. Clones of mutant bristles have a tendency to line up into straight bristle rows. Clones are straight and orderly near the wi...

The neural selector gene cut, a homeobox transcription factor, is required for the specification of the correct identity of external (bristle-type) sensory organs in Drosophila. Targets of cut function, however, have not been described. Here, we study bereft (bft) mutants, which exhibit loss or malformation of a majority of the interommatidial bristles of the eye and cause defects in other exte...