SUMMARY / RELATED TOPICS

Interphase

Interphase is the phase of the cell cycle in which a typical cell spends most of its life. During interphase, the cell copies its DNA in preparation for mitosis. Interphase is the'daily living' or metabolic phase of the cell, in which the cell obtains nutrients and metabolizes them, reads its DNA, conducts other "normal" cell functions; this phase was called the resting phase. However, interphase does not describe a cell, resting. A common misconception is that interphase is the first stage of mitosis, but since mitosis is the division of the nucleus, prophase is the first stage. In interphase, the cell gets itself ready for meiosis. Somatic cells, or normal diploid cells of the body, go through mitosis in order to reproduce themselves through cell division, whereas diploid germ cells go through meiosis in order to create haploid gametes for the purpose of sexual reproduction. There are three stages of cellular interphase, with each phase ending when a cellular checkpoint checks the accuracy of the stage's completion before proceeding to the next.

The stages of interphase are: G1, in which the cell functions normally. During this time, a high amount of protein synthesis occurs and the cell grows – more organelles are produced and the volume of the cytoplasm increases. If the cell is not to divide again, it will enter G0. Synthesis, in which the cell synthesizes its DNA and the chromosome number is doubled. G2, in which the cell resumes its growth in preparation for division; the mitochondria divide and the cell continues to grow. In plants, chloroplasts divide during G2. In addition, some cells that do not divide or enter a stage called G0, either a stage separate from interphase or an extended G1; the duration of time spent in interphase and in each stage of interphase is variable and depends on both the type of cell and the species of organism it belongs to. Most cells of adult mammals spend about 24 hours in interphase. Interphase includes G1, S, G2 phases. Mitosis and cytokinesis, are separate from interphase. DNA double-strand breaks can be repaired during interphase by two principal processes.

The first process, non-homologous end joining, can join the two broken ends of DNA in the G1, S and G2 phases of interphase. The second process, homologous recombinational repair, is more accurate than NHEJ in repairing double-strand breaks; however HRR is only active during the S and G2 phases of interphase when DNA replication is either accomplished or after it is completed, since HRR requires two adjacent homologous chromosomes. When G2 is completed, the cell enters a brief period of nuclear and cellular division, composed of mitosis and cytokinesis, respectively. After the successful completion of mitosis and cytokinesis, both resulting daughter cells re-enter G1 of interphase. In the cell cycle, interphase is preceded by telophase and cytokinesis of the M phase. In alternative fashion, interphase is sometimes interrupted by G0 phase, which, in some circumstances, may end and be followed by the remaining stages of interphase. After the successful completion of the G2 checkpoint, the final checkpoint in interphase, the cell proceeds to prophase, or in plants to preprophase, the first stage of mitosis.

G0 phase is viewed as either an extended G1 phase where the cell is neither dividing nor preparing to divide and or as a distinct quiescent stage which occurs outside of the cell cycle. In gamete production interphase is succeeded by meiosis. In programmed cell death, interphase is preempted by apoptosis. Prophase Prometaphase Metaphase Anaphase Telophase

Sound box

A sound box or sounding box is an open chamber in the body of a musical instrument which modifies the sound of the instrument, helps transfer that sound to the surrounding air. Objects respond more to vibrations at certain frequencies, known as resonances; the frequency and strength of the resonances of the body of a musical instrument have a significant impact on the tone quality it produces. The air inside the chamber has its own resonances, these interact with the resonances of the body, altering the resonances of the instrument as a whole; the sound box adds resonances at lower frequencies, enhancing the lower-frequency response of the instrument. The distinctive sound of an instrument with a sound box owes a lot to the alteration made to the tone. A sound box is found in most string instruments; the most notable exceptions are some electrically amplified instruments like the solid body electric guitar or the electric violin, the piano which uses only a sound board instead. Drumhead lutes such as the banjo or erhu have at least one open end of the sound box covered with animal skin.

Open back banjos are used for clawhammer and frailing, while those used for bluegrass have the back covered with a resonator. In some arrangements, loudspeakers are mounted on a sound box to enhance their output bass speakers. One notable example of this arrangement is called the bass reflex enclosure. However, in these cases the box resonance is tuned so as to make the sound more equal across frequencies, rather than to impart a particular character to the reinforced sound. Acoustic guitar Basic physics of the violin Filter Frequency response Resonance chamber

Deborah Margo

Deborah Margo is a Canadian multimedia artist known for her temporary installations and drawings. Her work has been exhibited in Canada, the United States, Mexico, she lives and works in Ottawa, Ontario. Born in Montreal, Margo attended the Haystack Mountain School of Crafts in Deer Isle, Maine before graduating from Concordia University in Montreal with a Bachelor in Fine Arts in 1984. Margo attended the Banff Centre School of Fine Arts, before receiving a Masters of Fine Arts from the Tyler School of Art at Temple University in Philadelphia. Margo has been a professor of sculpture at the University of Ottawa since 1999. Working with a variety of mediums, Margo's artistic practice focuses on temporary and ephemeral site-specific installations and object-making. Margo's practice is influenced by post-minimalism and methods of process art and her work engages with themes of growth, the passage of time, impressions of travel and the identity of public and private spaces. During her time at Concordia University, Margo participated in Interface, a student art event in Montreal that contributed to the rise of installation work on the Montreal art scene in the early 1980s.

Margo continued to work with sculpture and installation, graduated from the Tyler School of Art with an MFA in sculpture in 1990. She completed an artist residency at Struts Gallery in Sackville, New Brunswick in 1999, where she began an installation called Registers of Attendance. Other examples of her site-specific installation works include Reservoir – an Installation in Four Rooms, Light-Earth Drawings for the Owens Art Gallery in Sackville, NB, Medical Histories and After Hurricane Irene and Apidictor Symphony created with multi-media artist Annette Hegel. Margo's work appears in the collections of the Ottawa Art Gallery, the City of Ottawa Art Collection, the Owens Art Gallery, she has completed a number of public commissions around Ottawa, such as works for OC Transpo, as well as the new Ottawa Art Gallery's expansion project. Artist website CKCU: FM 93.1 Radio with Annette Hegel and Deborah Margo