Relatively large amounts of cell envelopes from Escherichia coli spheroplasts have been isolated in the zonal ultracentrifuge after deoxyribonuclease treatment of the disrupted spheroplasts. The Anderson B-IV zonal rotor was adapted to this isolation. After isopycnic zonal centrifugation through a 34 to 77% sucrose density gradient, the center of the zone containing the cell wall-cell membrane ...

For a set T of n points in a metric space (X, d), a point y ∈ X is dominated by a point x ∈ X if d(x, t) ≤ d(y, t) for all t ∈ T and there exists t ∈ T such that d(x, t) < d(y, t). The set of nondominated points of X is called the Pareto envelope of T. H. Kuhn (1973) established that in Euclidean spaces, the Pareto envelopes and the convex hulls coincide. Chalmet et al. (1981) characterized the...

The covering of the eggs in Russian sturgeon Acipenser gueldenstaedtii consists of three envelopes (the vitelline envelope, chorion and extrachorion) and is equipped with multiple micropyles. The most proximal to the oocyte is the vitelline envelope that consists of four layers of filamentous and trabecular material. The structural components of this envelope are synthesized by the oocyte (prim...

Daniel Berleant and Jianzhong Zhang Department of Electrical and Computer Engineering 2215 Coover Hall Iowa State University Ames, Iowa 50011 [email protected] Abstract Distribution Envelope Determination (DEnv) is a technique for computing descriptions of derived random variables. Derived random variables have samples that are a function of samples of other random variable(s), which are ter...

Flagella rotated exclusively counterclockwise in Escherichia coli cell envelopes prepared from wild-type cells, whose flagella rotated both clockwise and counterclockwise, from mutants rotating their flagella counterclockwise only, and even from mutants rotating their flagella primarily clockwise. Some factor needed for clockwise flagellar rotation appeared to be missing or defective in the cel...

Given a significative class F of commutative rings, we study the precise conditions under which a commutative ring R has an F -envelope. A full answer is obtained when F is the class of fields, semisimple commutative rings or integral domains. When F is the class of Noetherian rings, we give a full answer when the Krull dimension of R is zero and when the envelope is required to be epimorphic. ...

A well known theorem proved (independently) by J. Paris and H. Friedman states that BΣn+1 (the fragment of Arithmetic given by the collection scheme restricted to Σn+1–formulas) is a Πn+2–conservative extension of IΣn (the fragment given by the induction scheme restricted to Σn–formulas). In this paper, as a continuation of our previous work on collection schemes for ∆n+1(T)–formulas (see [4]),...

In the two-envelope problem, one is offered a choice between two envelopes, one containing twice as much money as the other. After seeing the contents of the chosen envelope, the chooser is offered the opportunity to exchange for the other envelope. However, it appears to be advantageous to switch, regardless of what is observed in the chosen envelope. This problem has an extensive literature w...

We investigate fully conglomerable coherent lower previsions in the sense of Walley, and some particular cases of interest: envelopes of fully conglomerable linear previsions, envelopes of countably additive linear previsions and fully disintegrable linear previsions. We study the connections with continuity and countable super-additivity, and show that full conglomerability can be characterise...