The tails in the Helix Nebula NGC 7293

We have examined a stream-source model for the production of the cometary tails observed in the Helix Nebula NGC 7293 in which a transonic or moderately supersonic stream of ionized gas overruns a source of ionized gas. Hydrodynamic calculations reveal velocity structures which are in good agreement with the observational data on tail velocities and are consistent with observations of the nebular structure. The results also are indicative of a stellar atmosphere origin for the cometary globules. Tail remnants persist for timescales long enough for their identification with faint striations visible in the nebula gas to be plausible.Comment: 7 pages, 6 figures, accepted for publication in A&

Renorming spaces with greedy bases

We study the problem of improving the greedy constant or the democracy constant of a basis of a Banach space by renorming. We prove that every Banach space with a greedy basis can be renormed, for a given \vare>0, so that the basis becomes (1+\vare)-democratic, and hence (2+\vare)-greedy, with respect to the new norm. If in addition the basis is bidemocratic, then there is a renorming so that in the new norm the basis is (1+\vare)-greedy. We also prove that in the latter result the additional assumption of the basis being bidemocratic can be removed for a large class of bases. Applications include the Haar systems in $L_p[0,1]$, $1<p<\infty$, and in dyadic Hardy space $H_1$, as well as the unit vector basis of Tsirelson space

William Baxter Harrill Family

Genealogical notes by Odell A. Harrill of the William and Sally Berryhill Baxter family, whose daughter Elizabeth Bitsy Baxter married Amos Harrill. William Baxter (1759 - 1853); Sally Berryhill Baxter (1766 - 1812)https://digitalcommons.gardner-webb.edu/fay-webb-gardner-harrill-family/1000/thumbnail.jp

The negro in California before 1890

Because so little has been written concerning the Negro in California and because the dynamic and romantic sequences in the development of this country have always interested me, I have become interested in knowing what part the Negro, free and slave, played in this panorama of events. Were there Negroes with early expeditions? To what extent did they migrate to the West when gold fever had become a nation-wide epidemic? Did they find gold? Where did they settle? What did they do? What difficulty did they encounter politically, socially, and economically? These are questions that have filled my mind, and to which I shall endeavor to find the answers

ON PART-TIME FARMING

Farm Management,