sigma factor

Examples of sigma factor in the following topics:

• Regulation of Sigma Factor Activity

  • Sigma factors are proteins that function in transcription initiation .
  • The activity of sigma factors within a cell is controlled in numerous ways.
  • However, if transcription of genes is not required, sigma factors will not be active.
  • The anti-sigma factors will bind to the RNA polymerase and prevent its binding to sigma factors present at the promoter site.
  • The anti-sigma factors are responsible for regulating inhibition of transcriptional activity in organisms that require sigma factor for proper transcription initiation.

• Regulation of Sigma Factor Translation

  • Sigma factor expression is often associated with environmental changes that cause changes in gene expression .
  • Sigma factors include numerous types of factors.
  • The most commonly studied sigma factors are often referred to as a RpoS proteins as the rpoS genes encode for sigma proteins of various sizes.
  • Specifically, the translational control of the sigma factor is a major level of control.
  • The translational control of sigma factors involves the presence and function of small noncoding RNAs.

• Grob Fragmentation

  • An interesting and generally useful skeletal transformation, involving specific carbon-carbon bond cleavage with accompanying conversion of certain sigma-bonds to pi-bonds, is known as the Grob fragmentation.
  • As background for discussing this reaction, it is helpful to define the concept of ethylogy, which may be regarded as the sigma-bond equivalent of vinylogy.
  • Whenever functional group interactions occur through a chain of covalent bonds (sigma or pi), stereoelectronic factors will play an important role.

• Total Quality Management Techniques

  • Six sigma, JIT, Pareto analysis, and the Five Whys technique are all approaches that can be used to improve overall quality.
  • Six Sigma drew inspiration from the quality improvement methodologies of preceding decades, including quality control, TQM, and Zero Defects.
  • The JIT inventory system focuses on having "the right material, at the right time, at the right place, and in the exact amount" and defines inventory as a cost factor.
  • It is now used within Kaizen (continuous improvement), lean manufacturing, and Six Sigma.
  • The Six Sigma management philosophy drew inspiration from the quality improvement methodologies of preceding decades, including TQM.

• B.1 Chapter 1

  • Calculate the temperature of the gas as a function of $\Sigma$.
  • $\displaystyle F(z) = -\frac{16 \sigma T^3}{3\kappa_R} \frac{\partial T}{\partial \Sigma} = \frac{16 \sigma T^3}{3\kappa_0 \rho^\alpha T^\beta} \frac{\partial T}{\partial \Sigma}$
  • $\displaystyle \frac{\partial T}{\partial \Sigma} = \frac{3\kappa_0 }{16 \sigma F} \Sigma^\alpha T^{\beta-\alpha-3} \left ( \frac{\mu m_p}{g_s k} \right )^\alpha$
  • which is larger by a factor of $n^3$, so the energy density within the water of the blackbody radiation is larger by a factor of $n^3$ than in air.
  • However, flux is related to the intensity which is energy density times the velocity so the flux is only larger by a factor of $n^2$.

• Example: Test for Independence

  • In this context, independence means that the two factors are not related.
  • Typically in social science research, researchers are interested in finding factors which are related (e.g., education and income, occupation and prestige, age and voting behavior).
  • where $\sigma_r$ is the sum over that row, $\sigma_c$ is the sum over that column, and $\sigma_t$ is the sum over the entire table.

• Bound-Free Transitions and Milne Relations

  • $\displaystyle d\sigma = \frac{8\pi^2}{3 \hbar^2 c} \frac{\hbar\omega}{2 d\omega} | {\bf d}_{if} |^2 \left [ \frac{dn}{dp d\Omega} dp d\Omega \right ] $
  • $\displaystyle \frac{d\sigma}{d\Omega} = \frac{p V m \omega}{6\pi c \hbar^3} |{\bf d}_{if} |^2 .$
  • $\displaystyle \frac{4\pi}{h\nu} N_n \sigma_{bf} ( 1 - e^{-h\nu/kT} ) B_\nu d\nu$
  • where $N_n$ is the number density of neutrals and the factor in front of the blackbody function accounts for stimulated recombination.
  • $\displaystyle \frac{\sigma_{bf}}{\sigma_{fb}} = \frac{N_+ N_e}{N_n} e^{h\nu/kT} \frac{f(v) c^2 h}{8\pi m \nu^2}$

• Oscillator Strengths

  • Except for the degeneracy factors for the two states, the Einstein coefficients will be the same, so we can define an oscillator strength for stimulated emission as well,

• B.7 Chapter 7

  • $\displaystyle \tau_{es} = l n_e \sigma_T = 2\sqrt{R^2 - b^2} \frac{\rho}{2m_p} (1 + X) \sigma_T$
  • What is the synchrotron emission from a single electron passing through a magnetic field in terms of the energy density of the magnetic field and the Lorentz factor of the electron?
  • What is the inverse Compton emission from a single electron passing through a gas of photons field in terms of the energy density of the photons and the Lorentz factor of the electron?
  • $\displaystyle P_\text{IC} = \frac{4}{3} \gamma^2 c \beta^2 \sigma_T \left ( \frac{4}{3} \gamma^2 c \beta^2 \sigma_T U_B n_e \frac{R}{c} \right ) n_e V$
  • $\displaystyle P_\text{IC} = \frac{64}{27} \gamma^4 \beta^4 c \sigma_T^2 U_B n_e^2 R^4$

• Standard Free Energy Changes

  • The other factor to keep in mind is that enthalpy values are normally given in $\frac{kJ}{mole}$ while entropy values are given in $\frac{J}{K\times mole} $ .