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Stays Constant (stay + constant)

Distribution by Scientific Domains

Life Sciences	50%

Selected Abstracts

A digitally controlled band-switching VCO using switching inductors and capacitors in 0.18 ,m CMOS

MICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 7 2008
Tienyu Chang
Abstract In this article, a digitally controlled band-switching voltage controlled oscillator (VCO) is designed and fabricated using TSMC 0.18 ,m CMOS technology. Design considerations regarding the power requirement and the phase noise of the VCO are discussed. Eight bands are set by three bits, with one bit controlling switching inductors, and two bits controlling switching capacitors. The VCO covers 2.9,3.45 GHz and 3.6,4.3 GHz using varactors for continuous frequency tuning. Phase noise of the VCO stays constant around ,110 dBc/Hz at 1 MHz offset for all bands. The fabricated VCO consumes 11 mA of current with 1.8 V supply voltage and has a small size of 730 ,m × 660 ,m. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1970,1973, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23496 [source]

Many but not all Genes in Chlamydomonas reinhardtii are Regulated by the Circadian Clock

PLANT BIOLOGY, Issue 6 2001
S. Jacobshagen
Abstract: Total RNA from autotrophic Chlamydomonas reinhardtii cultures grown in constant dim light and 17 °C constant temperature was subjected to Northern blot analyses. The mRNAs for cytochrome c, ,-tubulin, HSP70B (a chloroplastic heat shock protein of the 70 kD family), chloroplastic fructose-bisphosphate aldolase, and GAS3 (a "gamete-specific" protein of unknown function with high expression in gametes but low expression in vegetative cells) each exhibit a clear circadian rhythm in abundance. The rhythms differ significantly in phase and amplitude. The findings show that the genes for cytochrome c and ,-tubulin indeed are regulated by the circadian clock, as previously suggested. Experiments with cultures grown at 27 °C instead of 17 °C further revealed that the rhythms in mRNA abundance for HSP70B, chloroplastic aldolase, and GAS3 also occur with a similar period at the higher temperature. Thus, the rhythms conform to the criterion of temperature compensation for the period and therefore represent true circadian rhythms. In contrast, the combined amount of mRNA for ubiquitin 52 amino acid fusion protein and ubiquitin 78 to 81 amino acid fusion protein stays constant under both temperature conditions. Because the combined amount of mRNA for the ubiquitin fusion proteins was previously shown to cycle under diurnal conditions when cell division activity is high, our data suggest a regulation of these genes by the cell division cycle and not the circadian clock. In summary, our data, together with several other reports, suggest that the circadian clock regulates many but not all genes in Chlamydomonas reinhardtii. [source]

Down syndrome livebirth rate in the eastern part of Switzerland between 1980 and 1996 stays constant in spite of growing numbers of prenatally diagnosed and subsequently terminated cases

PRENATAL DIAGNOSIS, Issue 9 2002
Michael Mutter
No abstract is available for this article. [source]

Ternary fluorides BaMF4 (M = Zn, Mg and Mn) at low temperatures

ACTA CRYSTALLOGRAPHICA SECTION B, Issue 5 2009
Jose Maria Posse
Ternary fluorides BaMF4 (M = Zn, Mg, Mn) have been studied in the temperature range from 300 to 10,K using synchrotron and laboratory powder and single-crystal diffraction. The first two compounds are stable down to 10,K, while the third one undergoes a phase transition to an incommensurately modulated structure at approximately 250,K. The modulated phase is stable down to 10,K. The magnetic anomalies at 45 and 27,K observed previously in BaMnF4 are exclusively reflected in the behavior of the , component of the q vector, which assumes an irrational value of approximately 0.395,Å,1 at the temperature corresponding to the onset of the magnetic ordering and then stays constant down to 10,K. Mn,Mn distances do not indicate any structural response to the magnetic ordering. The formation of the modulated phase can be explained on the basis of simple geometrical criteria. The incorporation of the large Mn cation in the octahedral sheets implies an increase of the cavity in which the Ba ion is incorporated. This leads to the formation of the modulated structure to adapt the coordination sphere around Ba in such a way that the bond-valence sums can be kept close to the ideal value of two. With further lowering of the temperature, the charge balance around the Ba ion requires an increasingly anharmonic character of the modulation function of Ba, until finally at 10,K a crenel-like shape is assumed for the modulation of this atom. [source]