248 research outputs found
1+1+2 Electromagnetic perturbations on general LRS space-times: Regge-Wheeler and Bardeen-Press equations
We use the, covariant and gauge-invariant, 1+1+2 formalism developed by
Clarkson and Barrett, and develop new techniques, to decouple electromagnetic
(EM) perturbations on arbitrary locally rotationally symmetric (LRS)
space-times. Ultimately, we derive 3 decoupled complex equations governing 3
complex scalars. One of these is a new Regge-Wheeler (RW) equation generalized
for LRS space-times, whereas the remaining two are new generalizations of the
Bardeen-Press (BP) equations. This is achieved by first using linear algebra
techniques to rewrite the first-order Maxwell equations in a new complex 1+1+2
form which is conducive to decoupling. This new complex system immediately
yields the generalized RW equation, and furthermore, we also derive a decoupled
equation governing a newly defined complex EM 2-vector. Subsequently, a further
decomposition of the 1+1+2 formalism into a 1+1+1+1 formalism is developed,
allowing us to decompose the complex EM 2-vector, and its governing equations,
into spin-weighted scalars, giving rise to the generalized BP equations
A Novel, Low-Volume Method for Organ Culture of Embryonic Kidneys That Allows Development of Cortico-Medullary Anatomical Organization
Here, we present a novel method for culturing kidneys in low volumes of medium that offers more organotypic development compared to conventional methods. Organ culture is a powerful technique for studying renal development. It recapitulates many aspects of early development very well, but the established techniques have some disadvantages: in particular, they require relatively large volumes (1–3 mls) of culture medium, which can make high-throughput screens expensive, they require porous (filter) substrates which are difficult to modify chemically, and the organs produced do not achieve good cortico-medullary zonation. Here, we present a technique of growing kidney rudiments in very low volumes of medium–around 85 microliters–using silicone chambers. In this system, kidneys grow directly on glass, grow larger than in conventional culture and develop a clear anatomical cortico-medullary zonation with extended loops of Henle
Post-meiotic transcription in mouse testes detected with spermatid cDNA clones
cDNA clones to poly(A) + mRNA from spermatids have been obtained to study gene transcription in post-meiotic germ cells. Four cDNA clones detect mRNAs that increase in abundance in post-meiotic germ cells. One clone, pPM459, was shown to correspond to an mRNA that is transcribed after meiosis. Pulse-labelling experiments demonstrate transcription o5 the message in spermatids. These data constitute further evidence for post-meiotic gene transcription in spermatids.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/44190/1/10540_2005_Article_BF01116696.pd
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RNA POLYMERASE IN THE CENTRAL NERVOUS SYSTEM.
RNA polymerase in cerebral cortex is higher than in other regions of the rabbit brain. The average activity of the brain nuclei is higher than that of the liver nuclei. During development, the activity of RNA polymerase increases with maturation. © 1964
Recommended from our members
RNA POLYMERASE IN THE CENTRAL NERVOUS SYSTEM.
RNA polymerase in cerebral cortex is higher than in other regions of the rabbit brain. The average activity of the brain nuclei is higher than that of the liver nuclei. During development, the activity of RNA polymerase increases with maturation. © 1964
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