13,299 research outputs found
Fuse-holder concept expedites electronic component changes
Mounting circuit components in fuse holders facilitates component changing and extends component life with an estimated fifty percent saving of breadboard test time. Glass sleeves of the fuse holders allow easy component identification
Coded photographic proof paper could serve as convenient densitometer
Standard print-out proofing paper, preprinted with an identifying code, serves as convenient densitometer. Exposure to light darkens the paper and gives a measure of the density of the resultant photographic image or the total amount of exposure sustained by the paper
Design of Geometric Molecular Bonds
An example of a nonspecific molecular bond is the affinity of any positive
charge for any negative charge (like-unlike), or of nonpolar material for
itself when in aqueous solution (like-like). This contrasts specific bonds such
as the affinity of the DNA base A for T, but not for C, G, or another A. Recent
experimental breakthroughs in DNA nanotechnology demonstrate that a particular
nonspecific like-like bond ("blunt-end DNA stacking" that occurs between the
ends of any pair of DNA double-helices) can be used to create specific
"macrobonds" by careful geometric arrangement of many nonspecific blunt ends,
motivating the need for sets of macrobonds that are orthogonal: two macrobonds
not intended to bind should have relatively low binding strength, even when
misaligned.
To address this need, we introduce geometric orthogonal codes that abstractly
model the engineered DNA macrobonds as two-dimensional binary codewords. While
motivated by completely different applications, geometric orthogonal codes
share similar features to the optical orthogonal codes studied by Chung,
Salehi, and Wei. The main technical difference is the importance of 2D geometry
in defining codeword orthogonality.Comment: Accepted to appear in IEEE Transactions on Molecular, Biological, and
Multi-Scale Communication
Diversity and Arbitrage in a Regulatory Breakup Model
In 1999 Robert Fernholz observed an inconsistency between the normative
assumption of existence of an equivalent martingale measure (EMM) and the
empirical reality of diversity in equity markets. We explore a method of
imposing diversity on market models by a type of antitrust regulation that is
compatible with EMMs. The regulatory procedure breaks up companies that become
too large, while holding the total number of companies constant by imposing a
simultaneous merge of other companies. The regulatory events are assumed to
have no impact on portfolio values. As an example, regulation is imposed on a
market model in which diversity is maintained via a log-pole in the drift of
the largest company. The result is the removal of arbitrage opportunities from
this market while maintaining the market's diversity.Comment: 21 page
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