The vertical circuitry controls the vertical axis of the display and consists of an input coupling circuit, the input attenuator, and the vertical amplifier (for dual trace oscilloscopes, there are two identical vertical circuits, one for each channel). All signals connected to the vertical input jacks are fed through at least part of the vertical circuitry before they are used by other oscillo...

UNLABELLED Attenuation of photons degrades both the accuracy and the precision of SPECT images; attenuation correction algorithms correct the bias but cannot improve precision. Increased noise due to photon attenuation is most pronounced in regions deep in solid body sections, such as the brain and abdomen. We have quantified the degradation in performance in several estimation tasks that can b...

The DNA sequence changes of 31 mutations altering the attenuation control mechanism of the histidine operon are presented. These mutations are discussed in terms of a model for operon regulation that involves a his leader peptide gene whose translation regulates formation of alternative stem-loop structures in the his leader messenger RNA. Three suppressible mutations generate nonsense codons (...

Recombinant plasmids were constructed which carry defined regions of the threonine (thr) operon regulatory region of Escherichia coli. In vitro transcription experiments utilizing plasmid or restriction fragment templates showed that two major RNA transcripts, which differ in length by one to a few bases, are transcribed from this region. The approximate length of the transcripts is 150 to 170 ...

Rifampin-resistant mutants of Escherichia coli were isolated which had altered patterns of resistance or sensitivity to the inhibitory compounds 5-methyltryptophan and 5-methylanthranilate. The levels of tryptophan (trp) operon polypeptides in different rifampin-resistant mutants were elevated or reduced, in a manner consistent with their sensitivity to the two analogs. Complementation tests es...

Optical Amplifiers are essentials components in long haul fibre optic system. An amplifier is a electronic device that can increase the power of signal. An Optical Amplifier is effectively the opposite of attenuator while Optical Amplifiers provide gain and attenuator provides loss. When a signal travels in a optical fibre medium the signal suffer from various losses such as fibre losses, atten...

Organic ruthenium complexes and polymers with electrochromic activity in the near infrared region were prepared and their electrochemical and optical properties were investigated. The intrinsic attenuating property of these materials depends mainly on the concentration of the pair of ruthenium units in the complexes or polymers. One cured film had the attenuating power of 6.9 dB per micron thic...