Expansions for the capacitance of a cross concentric with a squarewith an identity

Two series for the geometrical capacitance C₀ of a coaxial structure which have certain theoretical and practical advantages are given. Not only do the series give the limiting behavior of C₀, they also permit the direct calculation of C₀ with sufficient accuracy for most engineering applications without resorting to elliptic functions     

Expansions for the capacitance of a square in a square with acomparison

Expansions are given for the capacitance per unit length for the geometry in which two infinite square cylinders are placed concentric with each other with their sides parallel to each other. A comparison is made with an expansion for the capacitance of the Bowman squares     

Expansions for the capacitance of the Bowman squares

Expansions are given for the capacitance per unit length for the geometry in which two infinite, square cylinders are placed concentric with each other and rotated so that the edges of the inner square are closest to the sides of the outer square     

A comparison of two approximations for the capacitance of a circleconcentric with a cross

The maximum and minimum capacitances on circles concentric with an internal cross are determined for a four-lobed and an eight-lobed equipotential distribution. It is found that the relative difference between the maximum and minimum effective capacitances of the eight-lobed curves is about an order of magnitude lower than the same difference in the four-lobed curves, for comparable geometries. It is shown that the average and the geometric means of the maximum and minimum effective capacitances on the multilobed curves are excellent approximations of the exact values. In fact, the error in the average of the maximum and minimum effective capacitances decreases exponentially as their relative difference decreases so that the average value for the eight-lobed case is a better approximation than the average for the four-lobed case by at least an order of magnitude, in the cases of most interest. The increased accuracy obtained from the eight-lobed equipotential distribution is presented in graphical form     

Expansions for the capacitance of a cross concentric with a circlewith an application

Expansions are given for the capacitance per unit length for the geometry that has a cross section in which an equiarmed cross is concentric with an external circle. An example of their application is given     

Regulation of the replication of the murine immunoglobulin heavy chain gene locus: evaluation of the role of the 3' regulatory region

DNA replication in mammalian cells is a precisely controlled physical and temporal process, likely involving cis-acting elements that control the region(s) from which replication initiates. In B cells, previous studies showed replication timing to be early throughout the immunoglobulin heavy chain (Igh) locus. The implication from replication timing studies in the B-cell line MPC11 was that early replication of the Igh locus was regulated by sequences downstream of the C alpha gene. A potential candidate for these replication control sequences was the 3' regulatory region of the Igh locus. Our results demonstrate, however, that the Igh locus maintains early replication in a B-cell line in which the 3' regulatory region has been deleted from one allele, thus indicating that replication timing of the locus is independent of this region. In non-B cells (murine erythroleukemia cells [MEL]), previous studies of segments within the mouse Igh locus demonstrated that DNA replication likely initiated downstream of the Igh gene cluster. Here we use recently cloned DNA to demonstrate that segments located sequentially downstream of the Igh 3' regulatory region continue to replicate progressively earlier in S phase in MEL. Furthermore, analysis by two-dimensional gel electrophoresis indicates that replication forks proceed exclusively in the 3'-to-5' direction through the region 3' of the Igh locus. Extrapolation from these data predicts that initiation of DNA replication occurs in MEL at one or more sites within a 90-kb interval located between 40 and 130 kb downstream of the 3' regulatory region.     

Compact planar microstrip-slotline symmetrical ring eight-portcomparator circuits

It is shown that the common eight-port comparator circuit may be constructed starting from a fully symmetrical eight-port device. The conditions for a lossless symmetrical eight-port circuit to be a symmetrical eight-port comparator are derived. These are used to design several versions of a planar ring microstrip-slotline comparator. Two experimental versions of such an eight-port circuit have been constructed using a planar microstrip-slotline technique. In the case of the second version, the ring circumference is only a wavelength at midband. This is the same circumference as the common 180° magic T ring circuit, four of which are frequently used to build a conventional comparator. The bandwidth of these eight-port planar ring circuits can be as much as 30% for a return loss better than 20 dB. A quasi-optic eight-port symmetrical comparator circuit based on a single wire grid is discussed. It has no bandwidth limitation     

Genetics of mouse antibodies. I. Linkage of the dextran response locus, VH-DEX, to allotype

The antibody response of mice to alpha-1,3 linked dextran is shown to be controlled by a heavy chain variable region gene, VH-DEX. The map distance between this gene and the heavy chain allotype locus is estimated to be 0.3 recombination units.