■ Abstract Important physical processes on the Sun, and especially in sunspots, occur on spatial scales at or below the limiting resolution of current solar telescopes. Over the past decade, using a number of new techniques, high-resolution observations have begun to reveal the complex thermal and magnetic structure of a sunspot, along with associated flows and oscillations. During this time re...

Under the expectation that experiments will soon give values for the 6ne structure intervals of the 2'I" state of helium to an accuracy of 1/10', we have undertaken a program of calculations which, it is hoped, will lead to a new determination of the 6ne-structure constant n. This paper gives a brief survey of the over-all program, and a detailed report of the successful completion of the', 6rs...

Though the dictyosome of the Golgi apparatus appears to be generally distributed in plant and animal cells, it is here described for the first time in the fungi. The present report illustrates, in electron micrographs of thin sections, the characteristic structure of the Golgi dictyosome in a special cell type of a supporting pseudo-tissue (the inner ectal excipulum) of a highly evolved Ascomyc...

Population genetic structure has important consequences in evolutionary processes and conservation genetics in animals. Fine-scale population genetic structure depends on the pattern of landscape, the permanent movement of individuals, and the dispersal of their genes during temporary mating events. The lesser flat-headed bat (Tylonycteris pachypus) is a nonmigratory Asian bat species that roos...

The mitotic, micronuclear division of the heterotrichous genus Blepharisma has been studied by electron microscopy. Dividing ciliates were selected from clone-derived mass cultures and fixed for electron microscopy by exposure to the vapor of 2 % osmium tetroxide; individual Blepharisma were encapsulated and sectioned. Distinctive features of the mitosis are the presence of an intact nuclear en...

Electron micrographs of staminate hair cells of Tradescantia reflexa indicate that early prophase chromosomes are composed of a number of helically arranged chromonemata. Favorable preparations reveal as many as 64 identifiable subsidiary strands, assumedly arranged as intertwined pairs to form a hierarchy of pairs of pairs. The helices of the smallest discernible units have a diameter of about...

In this paper we prove Jensen’s Coding Theorem, assuming ∼ 0#, via a proof that makes no use of the fine structure theory. We do need to quote Jensen’s Covering Theorem, whose proof uses fine-structural ideas, but make no direct use of these ideas. The key to our proof is the use of “coding delays.” Coding Theorem (Jensen) Suppose 〈M,A〉 is a model of ZFC + O# does not exist. Then there is an 〈M...

Recent studies have demonstrated the widespread occurrence of microtubules in the cytoplasm of both animal and plant cells (e.g., Burgos and Fawcett, 1955; Manton , 1959; Slautterback, 1963; Ledbetter and Porter, 1963). The microtubules have usually been examined in sectioned material after osmium tetroxide or glutaraldehyde fixation. Because of advantages in the negative staining technique, it...

The solar chromosphere is occupied with a wealth of fine structures referred to by diverse nomenclature. Recent identification of slow-mode magnetoacoustic shocks, excited by p-modes of photospheric oscillations, as plausible drivers of dynamic fibrils and spicules was followed by a surge of observational studies and numerical simulations attempting to reveal the role of chromospheric fine stru...

Visual displays in passive sonar based on the Fourier spectrogram are underpinned by detection models that rely on signal and noise power statistics. Time-frequency representations specialised for sparse signals achieve a sharper signal representation, either by reassigning signal energy based on temporal structure or by conveying temporal structure directly. However, temporal representations i...