Nodal period

The nodal period of a satellite is the time between successive passages of a satellite through successive orbital nodes. This applies to artificial, such as weather satellites, and natural satellites the moon. The nodal period of Earth's moon is 27.2122 days.

Near Earth-Satellites

The oblateness of the Earth has important effects of the orbits of near Earth-satellites. An expression for the nodal period () of a near circular orbit, such that the eccentricity (ε) is almost but not equal to zero, is:

References

Nodal

Nodal can refer to

Nodal (software)

Nodal is a generative software application for composing music. The software is produced at the Centre for Electronic Media Art (CEMA), Monash University, Australia. It uses a novel method for the notation and playing of MIDI based music. This method is based around the concept of a user-defined graph. The graph consists of nodes (musical events) and edges (connections between events). The composer interactively defines the graph, which is then traversed by any number of virtual players that play the musical events as they encounter them on the graph. The time taken by a player to travel from one node to another is based on the length of the edges that connect the nodes.

Supported Platforms and Versions

Early versions of Nodal were designed to run only on Mac OS X. As of version 1.1 beta (released in 2005), Nodal ran on Mac OS X 10.4, and Microsoft Windows (Vista or XP) operating systems. As of version 1.5, released in November 2009, the software became shareware in order to support its continued development. The current version is 1.9, released in October 2013 which runs on MacOS 10.6 and higher or Windows Vista, 7 and 8. This version has the ability to specify combinations of chords, sequences and randomised patterns within a single node and incorporates the use of scale modes. Nodal can be downloaded from the Nodal web site. It is also available from Apple's Mac App Store.

NODAL

Nodal is a secretory protein that in humans is encoded by the NODAL gene which is located on chromosome 10q22.1. It belongs to the Transforming Growth Factor (TGF-beta) superfamily. Like many other members of this superfamily it is involved in cell differentiation in early embryogenesis, playing a key role in signal transfer from the node, in the anterior primitive streak, to lateral plate mesoderm (LPM).

Nodal signaling is important very early in development for mesoderm and endoderm formation and subsequent organization of left-right axial structures. In addition, Nodal seems to have important functions in neural patterning, stem cell maintenance and many other developmental processes, including left/right handedness.

Signaling

Nodal can bind type I and type II Serine/Threonine kinase receptors, with Cripto-1 acting as its co-receptor. Signaling through SMAD 2/3 and subsequent translocation of SMAD 4 to the nucleus promotes the expression of genes involved in proliferation and differentiation. Nodal also further activates its own expression via a positive feedback loop. It is tightly regulated by inhibitors Lefty A, Lefty B, Cerberus, and Tomoregulin-1, which can interfere with Nodal receptor binding.

Period

Period may refer to:

Common meanings

Science and mathematics

Arts

Other uses

See also

Period (Another American Lie)

Period (Another American Lie) is the debut studio album by B.A.L.L., released in 1987 by Shimmy Disc.

Track listing

All lyrics written by Don Fleming, all music composed by B.A.L.L..

Personnel

Adapted from the Period (Another American Lie) liner notes.

Release history

References

Period (gene)

Period (per) is a gene located on the X chromosome of Drosophila melanogaster. Oscillations in levels of both per transcript and its corresponding protein PER have a period of approximately 24 hours and together play a central role in the molecular mechanism of the Drosophila biological clock driving circadian rhythms in eclosion and locomotor activity. Mutations in the per gene can shorten (per^S), lengthen (per^L), and even abolish (per⁰) the period of the circadian rhythm.

Discovery

The period gene and three mutants (per^S, per^L, and per⁰) were isolated in an EMS mutagenesis screen by Ronald Konopka and Seymour Benzer in 1971. The per^S, per^L, and per⁰ mutations were found to complement each other, so it was concluded that the three phenotypes were due to mutations in the same gene. The discovery of mutants that altered the period of circadian rhythms in eclosion and locomotor activity (per^S and per^L) indicated the role of the per gene in the clock itself and not an output pathway. The period gene was first sequenced in 1984 by Michael Rosbash and colleagues. In 1998, it was discovered that per produces two transcripts (differing only by the alternative splicing of a single untranslated intron) which both encode the PER protein.