text:
\section{Introduction \label{sec:intro}}

In Ref. \cite{VDM2011}, a common origin of the Fermi-liquid properties and
superconductivity in Nb-doped strontium titanate has been postulated and
induced from the phenomenological treatment of the resistivity data and
superconducting critical temperatures $T_{c}$. In the present work, we deduce
the temperature dependence of the resistivity and the superconducting $T_{c
$'s from microscopic model calculations. The relaxation rate in SrTi$_{1-x
$Nb$_{x}$O$_{3}$ can be accounted for by various scattering mechanisms. The
Fermi-liquid properties of a charge carrier gas in a crystal are provided by
the effective electron-electron interaction. This interaction is an interplay
of the Coulomb repulsion and the phonon-mediated attraction provided by the
Fr\"{o}hlich electron-phonon interaction with the optical phonons. Strontium
titanate is a strongly polar crystal with static dielectric constant
$\varepsilon_{0}\approx240$ and high-frequency dielectric constant
$\varepsilon_{\infty}\approx5.44$ \cite{PRB-STO}. The ratio $\eta
=\varepsilon_{\infty}/\varepsilon_{0}$ is very small in strontium titanate.
Due to a small $\eta$, the Coulomb repulsion and the optical phonon-mediated
attraction significantly compensate each other. Thus the contribution of the
other electron-phonon interactions, e.g., the deformation interaction with the
acoustic phonons, can be important for the sign of the total effective
electron-electron interaction. The fact that n-doped SrTiO$_{3}$ is a
superconductor \cite{Koonce,Reyren} implies that in this material the
phonon-mediated attraction due to both optical and acoustic phonons can
overcome the Coulomb repulsion. This yields superconductivity in strontium
titanate at low temperatures about $T\sim1$ K. In this connection, we verify
the suggestion \cite{VDM2011} that the DC resistivity and the relaxation rate
in Nb doped SrTiO$_{3}$ can be due to the effective electron-electron
interaction. There are two channels for the Fermi-liquid response of metals
and strongly doped semiconductors with complex conductivity bands due to the
electron-electron interaction: the normal and Umklapp
\cite{Lawrence,McD1,McD2} scattering processes.

Several other scattering mechanisms besides the effective electron-electron
interaction are present in strontium titanate. For completeness, they must be
included in the treatment, as far as they may contribute to the total
resistivity. In the present work, the following additional scattering
mechanisms are considered.

(1) The electron-phonon interaction can contribute to the effective
electron-electron scattering as mentioned above. Besides this, the direct
scattering of the electrons by the LO phonons can contribute to the
resistivity of the polar crystals in the same way as to the optical absorption
\cite{PRB-STO,VDM-PRL,TD2001}.

(2) In the context of small polarons, the electron-phonon scattering results
in a temperature dependence of the resistivity which is close to the $T^{2
$-behavior \cite{Zhao}. Therefore the electron -- LO-phonon scattering may
influence the Fermi-liquid-like temperature dependence of the DC response of
the charge carriers.

As established in Refs. \cite{PRB-STO,VDM-PRL}, the polarons in strontium
titanate are large (Fr\"{o}hlich) polarons rather than the small polarons
treated in Ref. \cite{Zhao}. In this connection, the electron -- LO-phonon
scattering is considered here in terms of the large polarons.

(3) Finally, the scattering of the electrons on the potential landscape
induced by the impurities (for example, the Nb donors) can bring a
non-negligible contribution to the total relaxation rate and resistivity,
especially in the low-temperature regime.

\section{Theory and results \label{sec:theoryandresults}}

\subsection{Baber scattering}

Within a parabolic model for a simple conductivity band, the electron-electron
interaction due to the normal (i.e., within the first Brillouin zone)
scattering processes does not contribute to the carrier electric response
owing to momentum conservation, even for an anisotropic band \cite{Maebashi}.
However, for a non-parabolic and/or complex conductivity band with, e.g.,
light and heavy carriers, the carrier response can be non-zero as first found
by Baber \cite{Baber,Giamarchi}. Thus the resistivity can be provided by the
interaction between charge carriers with different band masses or between
electrons and holes.

The Baber scattering mechanism is the most promising candidate to provide the
main contribution to the total relaxation rate of Nb doped strontium titanate.
We calculate the resistivity using the Boltzmann equation. Further on, we
follow the notations of Ref. \cite{Ziman}. The non-equilibrium distribution
function $f_{n,\mathbf{k}}$ for the carriers in the $n$-th subband is
determined a
\begin{equation}
f_{n,\mathbf{k}}=f_{n,\mathbf{k}}^{\left(  0\right)  }-\Phi_{n,\mathbf{k
}\frac{\partial f_{n,\mathbf{k}}^{\left(  0\right)  }}{\partial\varepsilon
_{n,\mathbf{k}}}, \label{a1
\end{equation}
where $f_{n,\mathbf{k}}^{\left(  0\right)  }\equiv f\left(  \varepsilon
_{n,\mathbf{k}}\right)  $ is the equilibrium electron distribution function in
the $n$-th subband of the conduction band
\begin{equation}
f\left(  \varepsilon_{n,\mathbf{k}}\right)  =\frac{1}{e^{\frac{\varepsilon
_{n,\mathbf{k}}-\mu}{k_{B}T}}+1},
\end{equation}
and $\varepsilon_{n,\mathbf{k}}$ is the electron energy.

The function $\Phi_{n,\mathbf{k}}$ is a measure of the deviation from
equilibrium in the electron distribution. The inner product of two real
functions $\Psi$ and $\Phi$ is defined by $\left\langle \Psi,\Phi\right\rangle
\equiv\sum_{n}\int d\mathbf{k}~\Psi_{n,\mathbf{k}}\Phi_{n,\mathbf{k}}$. The
Boltzmann equation can be written as
\begin{equation}
X=P\Phi, \label{BE
\end{equation}
where $P$ is the scattering operator which transforms the function $\Phi$ into
another function $\Psi=P\Phi$, and $X$ represents the left-hand side of the
Boltzmann equation
\begin{equation}
X=-\mathbf{v}_{n,\mathbf{k}}\cdot\frac{\partial f\left(  \varepsilon
_{n,\mathbf{k}}\right)  }{\partial T}\nabla T-\mathbf{v}_{n,\mathbf{k}}\cdot
e\frac{\partial f\left(  \varepsilon_{n,\mathbf{k}}\right)  }{\partial
\varepsilon_{n,\mathbf{k}}}\mathbf{E}. \label{X
\end{equation}
Here, $\mathbf{v}_{n,\mathbf{k}}$ is the velocity in the $n$-th subband
\begin{equation}
\mathbf{v}_{n,\mathbf{k}}=\frac{1}{\hbar}\frac{\partial\varepsilon
_{n,\mathbf{k}}}{\partial\mathbf{k}}. \label{vnk
\end{equation}

The collision integral of the Boltzmann equation can be represented as
$\left\langle \Phi,P\Phi\right\rangle $. The Boltzmann equation in the form
(\ref{BE}) implies tha
\begin{equation}
\left\langle \Phi,X\right\rangle =\left\langle \Phi,P\Phi\right\rangle .
\label{intf
\end{equation}
The variational principle established by Ziman \cite{Ziman} states that the
solution of the Boltzmann equation gives $\left\langle \Phi,P\Phi\right\rangle
$ its maximum value. Thus $\Phi_{n,\mathbf{k}}$ can be approximated by a trial
variational function.

In the notations of Ref. \cite{Ziman}, the DC resistivity is expressed by the
formul
\begin{equation}
\rho=\frac{\left\langle \Phi,P\Phi\right\rangle }{\left[  \left\langle
\Phi,X\left(  E=1\right)  \right\rangle \right]  ^{2}}, \label{rho
\end{equation}
where $X\left(  E=1\right)  $ represents the left-hand side of the Boltzmann
equation in a unit electric field $E=1$ (and in the absence of the temperature
gradients). The normalization factor is determined by the expressio
\begin{equation}
\left\langle \Phi,X\left(  E=1\right)  \right\rangle =2\sum_{n}\int
e\mathbf{v}_{n,\mathbf{k}}\Phi_{n,\mathbf{k}}\frac{\partial f\left(
\varepsilon_{n,\mathbf{k}}\right)  }{\partial\varepsilon_{n,\mathbf{k}}
\frac{d\mathbf{k}}{\left(  2\pi\right)  ^{3}}. \label{norm
\end{equation}
The collision integral for the electron-electron scattering processes i
\begin{align}
\left\langle \Phi,P\Phi\right\rangle  &  =\frac{1}{2k_{B}T}\sum_{n,n^{\prime
}\int\frac{d\mathbf{k}_{1}}{\left(  2\pi\right)  ^{3}}\frac{d\mathbf{k}_{2
}{\left(  2\pi\right)  ^{3}}\frac{d\mathbf{k}_{3}}{\left(  2\pi\right)  ^{3
}\frac{d\mathbf{k}_{4}}{\left(  2\pi\right)  ^{3}}\left(  \Phi_{n,1
+\Phi_{n^{\prime},2}-\Phi_{n,3}-\Phi_{n^{\prime},4}\right)  ^{2}\nonumber\\
&  \times\mathcal{P}\left(  n,1,n^{\prime},2\rightarrow n,3,n^{\prime
},4\right)  . \label{P1
\end{align}
Here, $\mathcal{P}\left(  n,1,n^{\prime},2\rightarrow n,3,n^{\prime},4\right)
$ is the scattering probability
\begin{align*}
\mathcal{P}\left(  n,1,n^{\prime},2\rightarrow n,3,n^{\prime},4\right)   &
=\left(  U_{\mathbf{k}_{1},\mathbf{k}_{3}}^{\left(  eff\right)  }\right)
^{2}f\left(  \varepsilon_{n,\mathbf{k}_{1}}\right)  f\left(  \varepsilon
_{n^{\prime},\mathbf{k}_{2}}\right)  \left[  1-f\left(  \varepsilon
_{n,\mathbf{k}_{3}}\right)  \right]  \left[  1-f\left(  \varepsilon
_{n^{\prime},\mathbf{k}_{4}}\right)  \right] \\
&  \times\frac{2\pi}{\hbar}\delta\left(  \varepsilon_{n,\mathbf{k}_{1
}+\varepsilon_{n^{\prime},\mathbf{k}_{2}}-\varepsilon_{n,\mathbf{k}_{3
}-\varepsilon_{n^{\prime},\mathbf{k}_{4}}\right) \\
&  \times\left(  2\pi\right)  ^{3}\delta\left(  \mathbf{k}_{1}+\mathbf{k
_{2}-\mathbf{k}_{3}-\mathbf{k}_{4}\right)  ,
\end{align*}
with $U_{\mathbf{k}_{1},\mathbf{k}_{3}}^{\left(  eff\right)  }$ the matrix
element of the effective electron-electron interaction, which includes both
the Coulomb repulsion and the phonon-mediated attraction.

The trial variational function $\Phi_{n,\mathbf{k}}$ is chosen in the form
\cite{Ziman
\[
\Phi_{n,\mathbf{k}}=\mathbf{v}_{n,\mathbf{k}}\cdot\mathbf{u
\]
where $\mathbf{u}$ is the unit vector parallel to the applied electric field.
Thus the collision integral i
\begin{align}
\left\langle \Phi,P\Phi\right\rangle  &  =\frac{1}{2k_{B}T}\frac{1}{\left(
2\pi\right)  ^{9}}\frac{2\pi}{\hbar}\sum_{n,n^{\prime}}\int d\mathbf{k
_{1}d\mathbf{k}_{2}d\mathbf{k}_{3}d\mathbf{k}_{4}\left(  \left(
\mathbf{v}_{n,\mathbf{k}_{1}}+\mathbf{v}_{n^{\prime},\mathbf{k}_{2
}-\mathbf{v}_{n,\mathbf{k}_{3}}-\mathbf{v}_{n^{\prime},\mathbf{k}_{4}}\right)
\cdot\mathbf{u}\right)  ^{2}\nonumber\\
&  \times\left(  U_{\mathbf{k}_{1},\mathbf{k}_{3}}^{\left(  eff\right)
}\right)  ^{2}f\left(  \varepsilon_{n,\mathbf{k}_{1}}\right)  f\left(
\varepsilon_{n^{\prime},\mathbf{k}_{2}}\right)  \left[  1-f\left(
\varepsilon_{n,\mathbf{k}_{3}}\right)  \right]  \left[  1-f\left(
\varepsilon_{n^{\prime},\mathbf{k}_{4}}\right)  \right] \nonumber\\
&  \times\delta\left(  \varepsilon_{n,\mathbf{k}_{1}}+\varepsilon_{n^{\prime
},\mathbf{k}_{2}}-\varepsilon_{n,\mathbf{k}_{3}}-\varepsilon_{n^{\prime
},\mathbf{k}_{4}}\right)  \delta\left(  \mathbf{k}_{1}+\mathbf{k
_{2}-\mathbf{k}_{3}-\mathbf{k}_{4}\right)  . \label{P2
\end{align}

The electrons in the conduction band are described by the matrix Hamiltonian
from Ref. \cite{VDM2011
\begin{equation}
H=4\left(
\begin{array}
[c]{ccc
\varepsilon_{1}\left(  \mathbf{k}\right)  & 0 & 0\\
0 & \varepsilon_{2}\left(  \mathbf{k}\right)  & 0\\
0 & 0 & \varepsilon_{3}\left(  \mathbf{k}\right)
\end{array}
\right)  +\frac{1}{2}W, \label{H
\end{equation}
with the energie
\begin{align}
\varepsilon_{1}  &  =t_{\delta}\sin^{2}\left(  \frac{a_{0}k_{x}}{2}\right)
+t_{\pi}\sin^{2}\left(  \frac{a_{0}k_{y}}{2}\right)  +t_{\pi}\sin^{2}\left(
\frac{a_{0}k_{z}}{2}\right)  ,\nonumber\\
\varepsilon_{2}  &  =t_{\pi}\sin^{2}\left(  \frac{a_{0}k_{x}}{2}\right)
+t_{\delta}\sin^{2}\left(  \frac{a_{0}k_{y}}{2}\right)  +t_{\pi}\sin
^{2}\left(  \frac{a_{0}k_{z}}{2}\right)  ,\nonumber\\
\varepsilon_{3}  &  =t_{\pi}\sin^{2}\left(  \frac{a_{0}k_{x}}{2}\right)
+t_{\pi}\sin^{2}\left(  \frac{a_{0}k_{y}}{2}\right)  +t_{\delta}\sin
^{2}\left(  \frac{a_{0}k_{z}}{2}\right)  ,
\end{align}
where $a_{0}$ is the lattice constant. The matrix $W$
\begin{equation}
W=\left(
\begin{array}
[c]{ccc
2D & \xi & \xi\\
\xi & 2D & \xi\\
\xi & \xi & -4D
\end{array}
\right)  \label{W
\end{equation}
describes the mixing of subbands within the conductivity band. We use the
values of the band parameters $t_{\delta},t_{\pi,}D,\xi$ from Ref.
\cite{VDM2011}: $t_{\delta}=35$ meV, $t_{\pi}=615$ meV, $\xi=18.8$ meV and
$D=2.2$ meV.

In the present treatment, we neglect the band mixing because it is relatively
small, and assume the anisotropic parabolic dispersion in each of three
subbands of the conductivity band (as in Refs. \cite{VDM2011,PRB-STO}) with
the tensor effective masses $\left\vert m_{jj}^{\left(  n\right)  }\right\vert
$ ($j=x,y,z,~n=1,2,3$). The masses $m_{jj}^{\left(  n\right)  }$ can take two
values: the \textquotedblleft light\textquotedblright\ mass $m_{\pi
=\frac{2\hbar^{2}}{a_{0}^{2}t_{\pi}}$ and the \textquotedblleft
heavy\textquotedblright\ mass $m_{\delta}=\frac{2\hbar^{2}}{a_{0}^{2
t_{\delta}}$. Using the above band parameters of strontium titanate and the
lattice constant $a_{0}=3.90
\operatorname{\text{\AA}
$, we arrive at the band masses $m_{\pi}\approx1.6m_{e}$ and $m_{\delta
}\approx29m_{e}$, where $m_{e}$ is the electron mass in vacuum.

The effective electron-electron interaction in SrTiO$_{3}$ is considered in
the following way. In the standard diagram technique, the effective
interaction corresponding to an elementary electron-electron scattering
process for a single-branch electron-phonon system, is given by the expression
\cite{Mahan
\begin{equation}
U_{\mathbf{k},\mathbf{k}^{\prime}}^{\left(  eff\right)  }\equiv U_{e-e
^{\left(  eff\right)  }\left(  \mathbf{q},\omega\right)  =U_{C}\left(
\mathbf{q}\right)  +\frac{1}{\hbar}\left\vert V_{\mathbf{q}}\right\vert
^{2}\mathcal{D}^{\left(  0\right)  }\left(  \mathbf{q},\omega\right)
,\nonumber
\end{equation}
where $\mathcal{D}^{\left(  0\right)  }\left(  \mathbf{q},\omega\right)  $ is
the free-phonon Green's function
\begin{equation}
\mathcal{D}^{\left(  0\right)  }\left(  \mathbf{q},\omega\right)
=-\frac{2\omega_{\mathbf{q}}}{\omega_{\mathbf{q}}^{2}-\omega^{2}}, \label{D0
\end{equation}
$\mathbf{q}$ is the momentum transfer $\mathbf{q}=\mathbf{k}^{\prime
}-\mathbf{k}$, and $\omega$ is equal to the transition frequency
$\omega=\left(  \varepsilon_{n^{\prime},\mathbf{k}^{\prime}}-\varepsilon
_{n,\mathbf{k}}\right)  /\hbar$ (where $n,n^{\prime}$ are the indices of the
subbands of the conduction band). Thus the effective interaction is
\begin{equation}
U_{e-e}^{\left(  eff\right)  }\left(  \mathbf{q},\omega\right)  =U_{C}\left(
\mathbf{q}\right)  -\left\vert V_{\mathbf{q}}\right\vert ^{2}\frac
{2\hbar\omega_{\mathbf{q}}}{\hbar^{2}\omega_{\mathbf{q}}^{2}-\left(
\varepsilon_{n^{\prime},\mathbf{k}^{\prime}}-\varepsilon_{n,\mathbf{k
}\right)  ^{2}}. \label{ueff2
\end{equation}
The effective interaction (\ref{ueff2}) is written for a one-branch phonon
system and does not account for screening. For our calculations, both the
screening and the multi-branch phonon system must be accounted for. The
extension of the above formulae to the multi-branch phonon system is
straightforward
\begin{equation}
U_{e-e}^{\left(  eff\right)  }\left(  \mathbf{q},\omega\right)  =U_{C}\left(
\mathbf{q}\right)  -\frac{1}{\hbar}\sum_{\lambda}\frac{2\omega_{\mathbf{q
,\lambda}\left\vert V_{\mathbf{q},\lambda}\right\vert ^{2}}{\omega
_{\mathbf{q},\lambda}^{2}-\omega^{2}}-\frac{1}{\hbar}\frac{2\omega
_{\mathbf{q}}^{\left(  ac\right)  }\left\vert V_{\mathbf{q}}^{\left(
ac\right)  }\right\vert ^{2}}{\left(  \omega_{\mathbf{q}}^{\left(  ac\right)
}\right)  ^{2}-\omega^{2}}, \label{ueff3
\end{equation}
where $\lambda$ labels different optical-phonon branches. The contribution to
the effective interaction due to the acoustic phonons (with the interaction
amplitudes $V_{\mathbf{q}}^{\left(  ac\right)  }$) is written here as a
separate term. The screening for the Coulomb interaction and for the
phonon-mediated interaction can be introduced here as in Ref. \cite{Mahan}
\begin{equation}
U_{e-e}^{\left(  eff\right)  }\left(  \mathbf{q},\omega\right)  =\frac{4\pi
e^{2}}{q^{2}\varepsilon_{\infty}\epsilon_{e}\left(  \mathbf{q},\omega\right)
}-\frac{1}{\hbar}\sum_{\lambda}\frac{\left\vert V_{\mathbf{q},\lambda
}\right\vert ^{2}}{\left[  \epsilon_{e}\left(  \mathbf{q},\omega\right)
\right]  ^{2}}\frac{2\omega_{\mathbf{q},\lambda}}{\omega_{\mathbf{q},\lambda
}^{2}-\omega^{2}}-\frac{1}{\hbar}\frac{2\omega_{\mathbf{q}}^{\left(
ac\right)  }\left\vert V_{\mathbf{q}}^{\left(  ac\right)  }\right\vert ^{2
}{\left(  \omega_{\mathbf{q}}^{\left(  ac\right)  }\right)  ^{2}-\omega^{2}},
\end{equation}
where $\epsilon_{e}\left(  \mathbf{q},\omega\right)  $ is the electron
screening factor. Note that screening is different for the Coulomb and
phonon-mediated interactions, and that the contribution due to the acoustic
phonons is not screened.

In the experimental situation of Ref. \cite{VDM2011}, the Fermi energy of the
electrons in the conduction band substantially exceeds their thermal energy
$k_{B}T$. Therefore only the electrons in a thermal layer near the Fermi
surface bring a dominating contribution to the relaxation rate. In other
words, the energies of the relevant electrons are close to the Fermi energy,
and the difference $\varepsilon_{n^{\prime},\mathbf{k}^{\prime}
-\varepsilon_{n,\mathbf{k}}\sim k_{B}T$ is relatively small with respect to
the Fermi energy.

The major contribution to the collision integral (\ref{P2}) lies in the range
of the momentum transfer $q\propto2k_{F}$, where $k_{F}$ is the electron wave
vector at the Fermi surface (in general, angle-dependent due to the band
anisotropy). In SrTiO$_{3}$, the corresponding acoustic-phonon energy
satisfies the condition $\hbar\omega_{\mathbf{q}}^{\left(  ac\right)  }\gtrsim
k_{B}T$ in the range $T<10
\operatorname{K
$ for all samples treated in the experiment \cite{VDM2011} except the
lowest-doped sample, for which $\hbar\omega_{\mathbf{q}}^{\left(  ac\right)
}/k_{B}T\sim1$ at $T=10
\operatorname{K
$. For the lower temperatures and/or for the higher doping contents the
aforesaid condition is fulfilled. The LO-phonon energies in SrTiO$_{3}$ are
much higher than the thermal energy in the considered temperature range. Thus,
owing to the fact that the electron-electron scattering effectively occurs
close to the Fermi surface, retardation effects in the phonon-mediated
interaction can be neglected. Therefore we can approximate the effective
interaction by the expressio
\begin{equation}
U_{e-e}^{\left(  eff\right)  }\left(  \mathbf{q}\right)  =\frac{4\pi e^{2
}{q^{2}\varepsilon_{\infty}\epsilon_{e}\left(  \mathbf{q}\right)
-\sum_{\lambda}\frac{2\left\vert V_{\mathbf{q},\lambda}\right\vert ^{2}
{\hbar\omega_{\mathbf{q},\lambda}\left[  \epsilon_{e}\left(  \mathbf{q
\right)  \right]  ^{2}}-\frac{2\left\vert V_{\mathbf{q}}^{\left(  ac\right)
}\right\vert ^{2}}{\hbar\omega_{\mathbf{q}}^{\left(  ac\right)  }},
\label{Ueff5
\end{equation}
where $\epsilon_{e}\left(  \mathbf{q}\right)  $ is the static electron
screening factor. The different screening of the Coulomb and phonon-mediated
interactions, however, can strongly influence the resulting interaction. In
the present calculation, the Thomas-Fermi (TF) screening factor is used in the
effective interaction
\begin{equation}
\epsilon_{e}\left(  \mathbf{q}\right)  =1+\frac{\kappa_{s}^{2}}{q^{2}},
\label{TF
\end{equation}
where $\kappa_{s}$ is the inverse TF screening length
\begin{equation}
\kappa_{s}=\left(  \frac{6\pi e^{2}n_{0}}{\varepsilon_{\infty}E_{F}}\right)
^{1/2}, \label{xp
\end{equation}
$n_{0}$ is the carrier density, and $E_{F}$ is the Fermi energy. Note that
$\epsilon_{e}\left(  \mathbf{q}\right)  $ is the static screening factor for
the electron gas (without the lattice polarization). Therefore $\kappa_{s}$
contains the high-frequency dielectric constant $\varepsilon_{\infty}$ rather
than the static dielectric constant $\varepsilon_{0}$. The material parameters
for the Fr\"{o}hlich interaction with the optical phonons are taken the same
as in Ref. \cite{PRB-STO}. The values of the TO- and LO- phonon frequencies,
the actual electron densities and the plasma frequencies $\omega_{p}$
determined from the experiment \cite{VDM-PRL} are represented in Table 1

\begin{table}[h] \centering
\caption{Optical-phonon frequencies, electron densities and plasma frequencies of doped strontium titanate
\begin{tabular}
[c]{|l|l|l|l|l|l|l|l|l|}\hline
$x$ & $x=0.1\%$ & $x=0.1\%$ & $x=0.2\%$ & $x=0.2\%$ & $x=0.9\%$ & $x=0.9\%$ &
$x=2\%$ & $x=2\%$\\
$T$ & $T=7$ K & $T=300$ K & $T=7$ K & $T=300$ K & $T=7$ K & $T=300$ K & $T=7$
K & $T=300$ K\\\hline
$\hbar\omega_{TO,1}$ (meV) & 2.27 & 11.5 & 2.63 & 11.5 & 6.01 & 12.1 & 8.51 &
13.0\\\hline
$\hbar\omega_{LO,1}$ (meV) & 21.2 & 21.2 & 21.2 & 21.2 & 21.2 & 21.2 & 21.2 &
21.2\\\hline
$\hbar\omega_{TO,2}$ (meV) & 21.2 & 21.8 & 21.2 & 21.8 & 21.2 & 21.8 & 21.2 &
21.8\\\hline
$\hbar\omega_{LO,2}$ (meV) & 58.4 & 58.4 & 58.4 & 58.4 & 58.4 & 58.4 & 58.4 &
58.4\\\hline
$\hbar\omega_{TO,3}$ (meV) & 67.6 & 67.1 & 67.6 & 67.1 & 67.6 & 67.1 & 67.6 &
67.1\\\hline
$\hbar\omega_{LO,3}$ (meV) & 98.7 & 98.7 & 98.7 & 98.7 & 98.7 & 98.7 & 98.7 &
98.7\\\hline
$n_{0}$ (cm$^{-3}$) & $1.7\times10^{19}$ & $1.7\times10^{19}$ & $3.4\times
10^{19}$ & $3.4\times10^{19}$ & $1.5\times10^{20}$ & $1.5\times10^{20}$ &
$3.4\times10^{20}$ & $3.4\times10^{20}$\\\hline
$\hbar\omega_{p}$ (eV) & 0.1 & 0.1 & 0.14 & 0.14 & 0.29 & 0.29 & 0.44 &
0.44\\\hline
\end{tabular}
\label{table1
\end{table

For the acoustic-phonon contribution, we use the interaction amplitudes for
the deformation potential from Ref. \cite{PD1985
\begin{equation}
V_{\mathbf{q}}^{\left(  ac\right)  }=\left(  4\pi\alpha_{ac}\right)
^{1/2}\frac{\hbar^{2}}{m_{D}}q^{1/2} \label{Vqac
\end{equation}
with the dimensionless coupling constan
\begin{equation}
\alpha_{ac}=\frac{E_{d}^{2}m_{D}^{2}}{8\pi n\hbar^{3}v}, \label{alphac
\end{equation}
where $n$ is the density, $E_{d}$ is the deformation potential, $v$ is the
sound velocity, and $m_{D}$ is the density-of-state band mass. It is i.a.
noting that the acoustic-phonon interaction amplitude (\ref{Vqac}) in fact
does not depend on the mass $m_{D}$. The sound velocity in strontium titanate
is taken $v\approx8.1\times10^{3
\operatorname{m
\operatorname{s
^{-1}$ \cite{Bell}.

The relaxation rate is determined using its relation to the resistivity
\begin{equation}
\frac{1}{\tau_{eff}}=\frac{\omega_{p}^{2}}{4\pi}\rho, \label{Tau
\end{equation}
where $\omega_{p}$ is the plasma frequency for the electron gas in the
conductivity band determined in the same way as in Ref. \cite{VDM2011}, and
listed in Table 1. In Fig. 1, we represent the numerical results for the
relaxation rate provided by Baber scattering as a function of temperature for
the actual electron densities, which are determined from the experimental
values of the doping level given in Ref. \cite{VDM2011}. We possess the
measured values for all material parameters of strontium titanate, except the
deformation potential $E_{d}$. In this connection, the value $E_{d}=23.
\operatorname{eV
$ has been chosen to fit the $T^{2}$-dependence of the relaxation rate to the
experimental data for the lowest doping level $x=0.1\%$. For the other
densities, we keep one and the same value of $E_{d}$. Typical values of the
deformation potential in other crystals found in the literature are about 10
to 30 eV, so that the chosen value is realistic.

The relaxation rates calculated with the same value of $E_{d}$ for all
densities reproduce the density dependence of the experimentally obtained
relaxation rate fairly well, except a residual background contribution which
does not vanish when the temperature tends to zero. Therefore the suggestion
\cite{VDM2011} that the $T^{2}$-dependence of the DC resistivity in
SrTi$_{1-x}$Nb$_{x}$O$_{3}$ can be provided by the Baber scattering mechanism
is supported by the present calculation.

When both optical and acoustic phonons are taken into account, the effective
electron-electron interaction at the Fermi surface can become attractive. With
optical phonons only (i.e., neglecting acoustic-phonon contribution) this
attraction is not possible. Moreover, the effective electron-electron
interaction without participation of the acoustic phonons is approximately
Coulomb-like. The relaxation rate for a Coulomb-like electron-electron
interaction monotonously decreases with an increasing density. The density
dependence of the relaxation rate observed experimentally can be explained by
a relative increase of the attraction provided by the acoustic phonons with
respect to the Coulomb repulsion and the interaction due to the optical
phonons. The latter two become more strongly screened when the density rises,
while the deformation potential is not screened. The increasing density
dependence of the relaxation rate therefore supports our hypothesis that the
phonon-mediated attraction (provided by both optical and acoustic phonons) in
strontium titanate can overcome the Coulomb repulsion even in the normal phase
-- at sufficiently high temperatures, when superconductivity does not exist.

\subsection{Other mechanisms}

We suggest that the relatively small residual relaxation rate in the Nb-doped
SrTiO$_{3}$ can be accounted for by the scattering of the electrons on the
potential landscape created by the impurities. The contribution to the DC
resistivity due to the scattering of the electrons by the potential of the
impurities is calculated using the approximation of the time-dependent
relaxation time within the Boltzmann equation approach. Assuming the
impurities chaotically distributed in space, the DC conductivity tensor is
determined by the expression (see Ref. \cite{Anselm}
\begin{equation}
\sigma_{ij}=-\frac{2e^{2}}{\hbar^{3}}\sum_{n}\int\frac{d\mathbf{k}}{\left(
2\pi\right)  ^{3}}\tau_{n}\left(  \mathbf{k}\right)  \left(  \frac{\partial
f_{0}\left(  \varepsilon_{n,\mathbf{k}}\right)  }{\partial\varepsilon
_{n,\mathbf{k}}}\right)  \left(  \mathbf{v}_{n,\mathbf{k}}\right)  _{i}\left(
\mathbf{v}_{n,\mathbf{k}}\right)  _{j
\end{equation}
where $\left(  \mathbf{v}_{n,\mathbf{k}}\right)  _{j}$ are the components of
the electron velocity in the conduction band.

For the relaxation time $\tau_{n}\left(  \mathbf{k}\right)  $, we apply the
approximation of the isotropic threefold degenerate conduction band with the
effective density-of-states band mass $m_{D}\equiv\left(  m_{xx}^{\left(
n\right)  }m_{yy}^{\left(  n\right)  }m_{zz}^{\left(  n\right)  }\right)
^{1/3}$. In this approximation, $\tau_{n}\left(  \mathbf{k}\right)
=\tau\left(  \mathbf{k}\right)  $, and the conductivity tensor is reduced to
the scalar expression $\sigma\equiv\rho^{-1}$
\begin{equation}
\frac{1}{\rho}=-2\frac{e^{2}}{\hbar m_{D}^{2}}\int\frac{d\mathbf{k}}{\left(
2\pi\right)  ^{3}}k^{2}\tau\left(  \mathbf{k}\right)  \left.  \left(
\frac{\partial f_{0}\left(  \varepsilon\right)  }{\partial\varepsilon}\right)
\right\vert _{\varepsilon=\varepsilon\left(  \mathbf{k}\right)  },
\label{cond
\end{equation}
where $\rho$ is the DC resistivity. The momentum-dependent relaxation time
$\tau\left(  \mathbf{k}\right)  $ for the chaotically distributed impurities
with the density $n_{I}$ is determined using the differential scattering
cross-section $\sigma\left(  k,\theta\right)  $ as \cite{Anselm}
\begin{equation}
\frac{1}{\tau\left(  k\right)  }=2\pi n_{I}v_{\mathbf{k}}\int_{0}^{\pi
\sigma\left(  k,\theta\right)  \left(  1-\cos\theta\right)  d\theta
\label{tauk
\end{equation}
The scattering cross-section $\sigma\left(  k,\theta\right)  $ is calculated
here in the Born approximation \cite{Landau3}

\begin{equation}
\sigma\left(  k,\theta\right)  =\frac{m_{D}^{2}}{4\pi^{2}\hbar^{4}}\left\vert
\int U\left(  \mathbf{r}\right)  e^{-i\mathbf{q}\cdot\mathbf{r}
d\mathbf{r}\right\vert ^{2}, \label{Born
\end{equation}
where $U\left(  \mathbf{r}\right)  $ is the potential created by an impurity,
and $\mathbf{q}=\mathbf{k}^{\prime}-\mathbf{k}$ is the momentum transfer (with
$k^{\prime}=k$, because the scattering is elastic).

To the best of our knowledge, the true potentials created by the impurities in
doped strontium titanate are not yet reliably known. We suggest that the
majority contribution to the impurity scattering is due to the ionized niobium
donors. Thus we assume that the density $n_{I}\approx n_{0}$ (where $n_{0}$ is
the electron density), and that the potential created by an ion can be modeled
by a pseudopotential corresponding to the {\normalsize Yukawa (screened
Coulomb) }potential
\begin{equation}
U\left(  \mathbf{r}\right)  =-\frac{U_{0}}{r}\exp\left(  -\kappa_{I}r\right)
, \label{U
\end{equation}
where $U_{0}=e^{2}/\varepsilon_{0}$, $\kappa_{I}$ is the inverse screening
length for the impurity potential. The scattering cross-section $\sigma\left(
k,\theta\right)  $ with the potential (\ref{U}) i
\begin{equation}
\sigma\left(  k,\theta\right)  =\left(  \frac{2m_{D}U_{0}}{\hbar^{2}}\right)
^{2}\frac{1}{\left(  2k^{2}\left(  1-\cos\theta\right)  +\kappa_{I
^{2}\right)  ^{2}}. \label{sigma
\end{equation}
Integrating in (\ref{tauk}) with (\ref{sigma}), the inverse momentum-dependent
relaxation time is obtained to b
\begin{equation}
\frac{1}{\tau\left(  k\right)  }=\frac{2\pi^{2}n_{I}v_{\mathbf{k}}}{\kappa
_{I}}\left(  \frac{2m_{D}U_{0}}{\hbar^{2}}\right)  ^{2}\frac{1}{\left(
4k^{2}+\kappa_{I}^{2}\right)  ^{3/2}}. \label{tauk1
\end{equation}
The contribution to the total relaxation rate (\ref{cond}) provided by the
impurity scattering, $1/\tau_{eff}^{\left(  I\right)  }$, with (\ref{tauk1})
is calculated numerically.

Here, the parameter to be estimated is the inverse screening length
$\kappa_{I}$. First, we can calculate $\kappa_{I}$ using the Thomas-Fermi (TF)
approximation
\begin{equation}
\kappa_{I}^{\left(  TF\right)  }=\left(  \frac{6\pi n_{0}e^{2}}{\varepsilon
_{0}E_{F}}\right)  ^{1/2}, \label{TF1
\end{equation}
where $E_{F}=\frac{\hbar^{2}}{2m_{D}}\left(  \pi^{2}n_{0}\right)  ^{2/3}$ is
the Fermi energy for the threefold degenerate conduction band. We use here the
static (rather than high-frequency) dielectric constant because the ions do
not move, and hence the lattice polarization (provided by the polar LO
phonons) reduces the Coulomb potential by the ratio $\varepsilon_{\infty
}/\varepsilon_{0}$.

The results for the $1/\tau_{eff}^{\left(  I\right)  }$ with (\ref{TF}) are
shown in Fig. 2 (\emph{a}). The values of $1/\tau_{eff}^{\left(  I\right)  }$
in the zero-temperature limit are in fair agreement with the experiment
\cite{VDM2011} for the samples with two higher doping levels $x=0.9\%$ and
$x=2\%$. However, for the two weaker doped samples, the residual relaxation
rate calculated using (\ref{TF1}) is overestimated with respect to the
experiment. Therefore we can suggest that the spatial cutoff of the impurity
potential can be provided also by additional mechanisms which can be
irrelevant to the presence of the electron gas and which therefore do not
vanish at low electron densities. In this connection, the contribution to the
total relaxation rate due to the impurity scattering has been also calculated
using the trial screening radius $r_{I}\equiv\kappa_{I}^{-1}\approx0.7
\operatorname{nm
$ which is one and the same for all samples and close to $\kappa_{I}^{\left(
TF\right)  }$ for the highest doping. The results for $1/\tau_{eff}^{\left(
I\right)  }$ in this case are shown in Fig. 2 (\emph{b}). We see that in this
case, the residual relaxation rate is in good agreement with the background
for the total relaxation rate measured in the experiment \cite{VDM2011}.
Moreover, the present result adequately reproduces the experimental density
dependence of the residual relaxation rate without varying $\kappa_{I}$.

In our treatment of the impurity screening length, we suppose this quantity to
be independent of doping in order to arrive at the experimentally observed
trend. The assumption that $\kappa_{I}$ does not depend on the doping means
that the dominant part of the impurity potential for the scattering processes
is essentially short-range. (Note that $r_{I}\approx0.7
\operatorname{nm
$ is about twice the lattice parameter.) The Nb-ion is larger than the Ti-atom
and as a consequence the ions around the Nb-donors are radially displaced.
This has consequences for the local electronic structure and -- as far as we
know -- nobody has analyzed this theoretically for Nb-donors in SrTiO$_{3}$.
Empirically we know that even for a low Nb-concentration, no bound
donor-states are formed. This is totally different from the case of Si doped
with phosphor.

For the Yukawa potential (\ref{U}), a critical value $\kappa_{I}^{\left(
c\right)  }$ exists such that for $\kappa_{I}>\kappa_{I}^{\left(  c\right)
$, there are no bound states in that potential. The Monte Carlo calculation
for a particle with an isotropic parabolic dispersion law \cite{Luo} gives
\begin{equation}
\tilde{\kappa}_{I}^{\left(  c\right)  }\approx1.1906\tilde{U},
\label{critical
\end{equation}
where $\tilde{\kappa}_{I}^{\left(  c\right)  }$ and $\tilde{U}$ are,
respectively, $\kappa_{I}^{\left(  c\right)  }$ and $U$ in the atomic units.
We can estimate $\tilde{\kappa}_{I}^{\left(  c\right)  }$ for an anisotropic
band using the parameters $\tilde{\kappa}_{I}^{\left(  c\right)  }$ and
$\tilde{U}$ expressed in the effective atomic units for a crystal:
$\tilde{\kappa}_{I}^{\left(  c\right)  }=\kappa_{I}^{\left(  c\right)
a_{B}^{\ast}$, $\tilde{U}=U/\left(  a_{B}^{\ast}E_{h}^{\ast}\right)  $, with
the effective Bohr radius $a_{B}^{\ast}=\varepsilon_{0}\hbar^{2}/\left(
m_{D}e^{2}\right)  $ and the effective Hartree energy $E_{h}^{\ast}=m_{D
e^{4}\left(  \varepsilon_{0}\hbar\right)  ^{2}$. In Nb-doped strontium
titanate, the critical inverse screening radius corresponding to
(\ref{critical}), is $r_{I}^{\left(  c\right)  }\approx2.
\operatorname{nm
$. The aforesaid value $r_{I}\approx0.7
\operatorname{nm
$ yields $\tilde{\kappa}_{I}\approx3.9\tilde{U}$, substantially larger than
$\tilde{\kappa}_{I}^{\left(  c\right)  }$. Thus, in accordance with the
aforesaid experimental evidence, there are no bound states in the Yukawa
potential with the parameters of the Nb-doped SrTiO$_{3}$ chosen in the
present calculation.

The other mechanisms which might contribute to the resistivity of SrTi$_{1-x
$Nb$_{x}$O$_{3}$ are the direct scattering of the electrons by the optical
phonons and the Umklapp electron-electron scattering. These contributions have
been separately calculated within the same kinetic equation approach as the
aforesaid contributions due to the Baber and impurity scattering. In Fig. 3,
the contribution to the relaxation rate due to the electron -- LO-phonon
scattering is plotted as a function of the temperature for the actual electron
densities in the samples studied experimentally in Ref. \cite{VDM2011}. Under
the experimental conditions of Ref. \cite{VDM2011}, the electron -- LO-phonon
scattering contribution to the relaxation rate appears to be relatively small
with respect to the relaxation rate provided by the Baber mechanism.
Furthermore, the relaxation rate due to the electron -- LO-phonon scattering
strongly decreases with decreasing temperature. Therefore the electron-phonon
scattering is not one of the dominating mechanisms of the DC conductivity in
Nb doped SrTiO$_{3}$.

Finally, the Umklapp electron-electron scattering was considered in Ref.
\cite{VDM2011} as one of possible sources for the DC resistivity in Nb-doped
SrTiO$_{3}$. For the electron resistivity in metals, the Baber mechanism plays
a minor role, and the Umklapp scattering can be sufficient to explain the
Fermi-liquid temperature dependence of the resistivity
\cite{Lawrence,McD1,McD2}. However, the Umklapp electron-electron scattering
remarkably contributes to the resistivity only when both the initial and final
momenta of the two electrons in the elementary scattering process lie in the
thermal layer near the Fermi surface. Therefore, e.g. in the simple case of a
spherically symmetric conductivity band, the Umklapp scattering does not
contribute to the resistivity when the maximal possible value of the momentum
transfer $q_{\max}=4\hbar k_{F}$ (where $k_{F}$ is the Fermi wave vector) is
smaller than the modulus of the reciprocal lattice vector $\mathbf{g}$.
Therefore the Umklapp processes can be non-negligible only at sufficiently
high densities. For an anisotropic conductivity band with a warped Fermi
surface (that is just the case in SrTiO$_{3}$) the restriction for the density
can be softened with respect to that for a spherically symmetric band.
However, it is not a priori known whether the Umklapp scattering is relevant
for the carrier densities in the experiment \cite{VDM2011}. Therefore we have
estimated the Umklapp contribution to the relaxation rate in strontium
titanate within the kinetic equation approach.

In Fig. 4, the relaxation rate provided by the Umklapp electron-electron
scattering (multiplied by $\hbar/\mathcal{G}^{2},$ where $\mathcal{G}<1$ is
the dimensionless interference factor for the Umklapp processes \cite{Ziman})
is plotted as a function of the electron density for the temperature $T=80$ K.
The relaxation rate provided by the Umklapp processes in strontium titanate is
not vanishingly small for densities higher than the threshold value
$n_{0}\approx8\times10^{20
\operatorname{cm
^{-3}$. However, the carrier densities achieved in the experiment
\cite{VDM2011} are substantially lower than this threshold value. In the
figure, the arrows show the actual electron densities in the experiment
\cite{VDM2011}. For the experimental densities $n_{0}\sim10^{19}$~cm$^{-3}$ to
$10^{20}$~cm$^{-3}$, the relaxation rate provided by the Umklapp
electron-electron scattering is vanishingly small with respect to the measured
values of $1/\tau$. The relaxation rate due to the Umklapp processes becomes
non-negligible in strontium titanate only for the electron densities
$n_{0}\gtrsim10^{22
\operatorname{cm
^{-3}$, much higher than the densities relevant for the experiment
\cite{VDM2011}. The conclusion follows that the contribution by Umklapp
processes to the Fermi-liquid behavior of relaxation rate and resistivity in
SrTi$_{1-x}$Nb$_{x}$O$_{3}$ is negligible. In summary, the electron --
LO-phonon and Umklapp scattering contributions to the DC resistivity of the Nb
doped strontium titanate bring only relatively small corrections in the
present treatment as far as it is related to the interpretation of the
experiment \cite{VDM2011}.

The relative contributions of different scattering mechanisms to the total
relaxation rate as a function of temperature are shown in Fig. 5 for the
sample with the doping content $x=0.002$. In the low-temperature range, the
residual scattering of the electrons on the potential landscape of the
impurities dominates. For higher temperatures, the Baber scattering plays a
key role providing the Fermi-liquid $T^{2}$-dependence of the total relaxation
rate. The electron -- LO-phonon scattering only slightly contributes to the
total relaxation rate and only at sufficiently high temperatures. Thus the
main contribution to the relaxation rate is brought by the Baber scattering at
moderate temperatures and by the scattering by the donors at low temperatures.

The total relaxation rate calculated taking into account the Baber,
electron-impurity, and electron -- LO-phonon scattering mechanisms is plotted
in Fig. 6. The $T^{2}$ temperature dependence of the relaxation rate is
completely due to the Baber mechanism. The scattering by donors is responsible
for the residual relaxation rate which constitutes the background resistivity
in SrTi$_{1-x}$Nb$_{x}$O$_{3}$. We see that the aforesaid mechanisms
convincingly explain both the temperature and density dependences for the
experimentally measured relaxation rate.

\section{Conclusions \label{sec:conclusions}}

In conclusion, the DC resistivity of Nb-doped strontium titanate is explained
in terms of two dominating mechanisms: Baber scattering with participation of
both Coulomb and phonon-mediated electron-electron interactions provides the
$T^{2}$-dependence of the resistivity and of the relaxation rate, while the
scattering on the potential landscape caused by impurities yields the residual
relaxation rate which does not vanish at $T=0$. The calculated relaxation
rates are in a good agreement with the experiment \cite{VDM2011}. Thus the
hypothesis on a common origin of two phenomena in SrTiO3 -- superconductivity
and the Fermi-liquid behavior of the resistivity -- is supported by the
microscopic calculations.

\begin{acknowledgments}
This work was supported by FWO-V projects G.0356.06, G.0370.09N, G.0180.09N,
G.0365.08, the WOG WO.035.04N (Belgium), the SNSF through Grant No.
200020-140761 and the National Center of Competence in Research (NCCR)
\textquotedblleft Materials with Novel Electronic Properties-MaNEP".
\end{acknowledgments}

redpajama_set_name: RedPajamaArXiv


Juventus manager Massimiliano Allegri talked about Paulo Dybala at a press conference ahead of Juventus fixture against Sassuolo tomorrow. Dybala has hardly played for Juventus, since the arrival of €110million man Cristiano Ronaldo.
I am very happy with how he started against Parma, already with a different approach, he has to do like others, he has to train, he has to find a good condition, and now he plays every three days, from here to December we have two goals, pass the round in the Champions League and keep the top of the Serie A standings.
He did not play here because I made different choices, his qualities are not in question, but he has to question himself, I have to make choices, but if tomorrow he plays and maybe he's wrong, then he needs to make changes.


text:
namespace ui {

namespace {

std::vector<drmModeModeInfo> GetDrmModeVector(drmModeConnector* connector) {
  std::vector<drmModeModeInfo> modes;
  for (int i = 0; i < connector->count_modes; ++i)
    modes.push_back(connector->modes[i]);

  return modes;
}

void FillPowerFunctionValues(std::vector<display::GammaRampRGBEntry>* table,
                             size_t table_size,
                             float max_value,
                             float exponent) {
  for (size_t i = 0; i < table_size; i++) {
    const uint16_t v = max_value * std::numeric_limits<uint16_t>::max() *
                       pow((static_cast<float>(i) + 1) / table_size, exponent);
    struct display::GammaRampRGBEntry gamma_entry = {v, v, v};
    table->push_back(gamma_entry);
  }
}

}  // namespace

DrmDisplay::PrivacyScreenProperty::PrivacyScreenProperty(
    const scoped_refptr<DrmDevice>& drm,
    drmModeConnector* connector)
    : drm_(drm), connector_(connector) {
  privacy_screen_hw_state_ =
      drm_->GetProperty(connector_, kPrivacyScreenHwStatePropertyName);
  privacy_screen_sw_state_ =
      drm_->GetProperty(connector_, kPrivacyScreenSwStatePropertyName);

  if (!privacy_screen_hw_state_ || !privacy_screen_sw_state_) {
    privacy_screen_hw_state_.reset();
    privacy_screen_sw_state_.reset();

    property_last_ = display::kPrivacyScreenLegacyStateLast;
    privacy_screen_legacy_ =
        drm_->GetProperty(connector_, kPrivacyScreenPropertyNameLegacy);
  }
}

DrmDisplay::PrivacyScreenProperty::~PrivacyScreenProperty() = default;

bool DrmDisplay::PrivacyScreenProperty::SetPrivacyScreenProperty(bool enabled) {
  drmModePropertyRes* property = GetWritePrivacyScreenProperty();
  if (!property) {
    LOG(ERROR)
        << "Privacy screen is not supported but an attempt to set it was made.";
    return false;
  }

  const display::PrivacyScreenState state_to_set =
      enabled ? display::kEnabled : display::kDisabled;
  if (!drm_->SetProperty(connector_->connector_id, property->prop_id,
                         GetDrmValueForInternalType(state_to_set, *property,
                                                    kPrivacyScreenStates))) {
    LOG(ERROR) << (enabled ? "Enabling" : "Disabling") << " property '"
               << property->name << "' failed!";
    return false;
  }

  return ValidateCurrentStateAgainst(enabled);
}

display::PrivacyScreenState
DrmDisplay::PrivacyScreenProperty::GetPrivacyScreenState() const {
  drmModePropertyRes* property = GetReadPrivacyScreenProperty();
  if (!property) {
    LOG(ERROR) << "Privacy screen is not supported but an attempt to read its "
                  "state was made.";
    return display::kNotSupported;
  }

  ScopedDrmObjectPropertyPtr property_values(drm_->GetObjectProperties(
      connector_->connector_id, DRM_MODE_OBJECT_CONNECTOR));
  if (!property_values) {
    PLOG(INFO) << "Properties no longer valid for connector "
               << connector_->connector_id << ".";
    return display::kNotSupported;
  }

  const std::string privacy_screen_state_name =
      GetEnumNameForProperty(*property, *property_values);
  const display::PrivacyScreenState* state = GetInternalTypeValueFromDrmEnum(
      privacy_screen_state_name, kPrivacyScreenStates);
  return state ? *state : display::kNotSupported;
}

bool DrmDisplay::PrivacyScreenProperty::ValidateCurrentStateAgainst(
    bool enabled) const {
  display::PrivacyScreenState current_state = GetPrivacyScreenState();
  if (current_state == display::kNotSupported)
    return false;

  bool currently_on = false;
  if (current_state == display::kEnabled ||
      current_state == display::kEnabledLocked) {
    currently_on = true;
  }
  return currently_on == enabled;
}

drmModePropertyRes*
DrmDisplay::PrivacyScreenProperty::GetReadPrivacyScreenProperty() const {
  if (privacy_screen_hw_state_ && privacy_screen_sw_state_)
    return privacy_screen_hw_state_.get();
  return privacy_screen_legacy_.get();
}

drmModePropertyRes*
DrmDisplay::PrivacyScreenProperty::GetWritePrivacyScreenProperty() const {
  if (privacy_screen_hw_state_ && privacy_screen_sw_state_)
    return privacy_screen_sw_state_.get();
  return privacy_screen_legacy_.get();
}

DrmDisplay::DrmDisplay(const scoped_refptr<DrmDevice>& drm)
    : drm_(drm), current_color_space_(gfx::ColorSpace::CreateSRGB()) {}

DrmDisplay::~DrmDisplay() = default;

uint32_t DrmDisplay::connector() const {
  DCHECK(connector_);
  return connector_->connector_id;
}

std::unique_ptr<display::DisplaySnapshot> DrmDisplay::Update(
    HardwareDisplayControllerInfo* info,
    uint8_t device_index) {
  std::unique_ptr<display::DisplaySnapshot> params = CreateDisplaySnapshot(
      info, drm_->get_fd(), drm_->device_path(), device_index, origin_);
  crtc_ = info->crtc()->crtc_id;
  // TODO(crbug.com/1119499): consider taking ownership of |info->connector()|
  connector_ = ScopedDrmConnectorPtr(
      drm_->GetConnector(info->connector()->connector_id));
  if (!connector_) {
    PLOG(ERROR) << "Failed to get connector "
                << info->connector()->connector_id;
    return nullptr;
  }

  display_id_ = params->display_id();
  modes_ = GetDrmModeVector(info->connector());
  is_hdr_capable_ =
      params->bits_per_channel() > 8 && params->color_space().IsHDR();
  privacy_screen_property_ =
      std::make_unique<PrivacyScreenProperty>(drm(), connector_.get());
#if BUILDFLAG(IS_CHROMEOS_ASH)
  is_hdr_capable_ =
      is_hdr_capable_ &&
      base::FeatureList::IsEnabled(display::features::kUseHDRTransferFunction);
#endif

  return params;
}

// When reading DRM state always check that it's still valid. Any sort of events
// (such as disconnects) may invalidate the state.
bool DrmDisplay::GetHDCPState(
    display::HDCPState* hdcp_state,
    display::ContentProtectionMethod* protection_method) {
  if (!connector_)
    return false;

  TRACE_EVENT1("drm", "DrmDisplay::GetHDCPState", "connector",
               connector_->connector_id);
  ScopedDrmPropertyPtr hdcp_property(
      drm_->GetProperty(connector_.get(), kContentProtection));
  if (!hdcp_property) {
    PLOG(INFO) << "'" << kContentProtection << "' property doesn't exist.";
    return false;
  }

  ScopedDrmObjectPropertyPtr property_values(drm_->GetObjectProperties(
      connector_->connector_id, DRM_MODE_OBJECT_CONNECTOR));
  if (!property_values) {
    PLOG(INFO) << "Properties no longer valid for connector "
               << connector_->connector_id << ".";
    return false;
  }

  const display::HDCPState* hw_hdcp_state =
      GetDrmPropertyCurrentValueAsInternalType(
          kContentProtectionStates, *hdcp_property, *property_values);
  if (hw_hdcp_state) {
    VLOG(3) << "HDCP state: " << *hw_hdcp_state << ".";
    *hdcp_state = *hw_hdcp_state;
  } else {
    LOG(ERROR) << "Unknown content protection value.";
    return false;
  }

  if (*hdcp_state == display::HDCP_STATE_UNDESIRED) {
    // ProtectionMethod doesn't matter if we don't have it desired/enabled.
    *protection_method = display::CONTENT_PROTECTION_METHOD_NONE;
    return true;
  }

  ScopedDrmPropertyPtr content_type_property(
      drm_->GetProperty(connector_.get(), kHdcpContentType));
  if (!content_type_property) {
    // This won't exist if the driver doesn't support HDCP 2.2, so default it in
    // that case.
    VLOG(3) << "HDCP Content Type not supported, default to Type 0";
    *protection_method = display::CONTENT_PROTECTION_METHOD_HDCP_TYPE_0;
    return true;
  }

  const display::ContentProtectionMethod* hw_protection_method =
      GetDrmPropertyCurrentValueAsInternalType(
          kHdcpContentTypeStates, *content_type_property, *property_values);
  if (hw_protection_method) {
    VLOG(3) << "Content Protection Method: " << *protection_method << ".";
    *protection_method = *hw_protection_method;
  } else {
    LOG(ERROR) << "Unknown HDCP content type value.";
    return false;
  }

  return true;
}

bool DrmDisplay::SetHDCPState(
    display::HDCPState state,
    display::ContentProtectionMethod protection_method) {
  if (!connector_) {
    return false;
  }

  if (protection_method != display::CONTENT_PROTECTION_METHOD_NONE) {
    ScopedDrmPropertyPtr content_type_property(
        drm_->GetProperty(connector_.get(), kHdcpContentType));
    if (!content_type_property) {
      // If the driver doesn't support HDCP 2.2, this won't exist.
      if (protection_method & display::CONTENT_PROTECTION_METHOD_HDCP_TYPE_1) {
        // We can't do this, since we can't specify the content type.
        VLOG(3)
            << "Cannot set HDCP Content Type 1 since driver doesn't support it";
        return false;
      }
      VLOG(3) << "HDCP Content Type not supported, default to Type 0";
    } else if (!drm_->SetProperty(connector_->connector_id,
                                  content_type_property->prop_id,
                                  GetDrmValueForInternalType(
                                      protection_method, *content_type_property,
                                      kHdcpContentTypeStates))) {
      // Failed setting HDCP Content Type.
      return false;
    }
  }

  ScopedDrmPropertyPtr hdcp_property(
      drm_->GetProperty(connector_.get(), kContentProtection));
  if (!hdcp_property) {
    PLOG(INFO) << "'" << kContentProtection << "' property doesn't exist.";
    return false;
  }

  return drm_->SetProperty(
      connector_->connector_id, hdcp_property->prop_id,
      GetDrmValueForInternalType(state, *hdcp_property,
                                 kContentProtectionStates));
}

void DrmDisplay::SetColorMatrix(const std::vector<float>& color_matrix) {
  if (!drm_->plane_manager()->SetColorMatrix(crtc_, color_matrix)) {
    LOG(ERROR) << "Failed to set color matrix for display: crtc_id = " << crtc_;
  }
}

void DrmDisplay::SetBackgroundColor(const uint64_t background_color) {
  drm_->plane_manager()->SetBackgroundColor(crtc_, background_color);
}

void DrmDisplay::SetGammaCorrection(
    const std::vector<display::GammaRampRGBEntry>& degamma_lut,
    const std::vector<display::GammaRampRGBEntry>& gamma_lut) {
  // When both |degamma_lut| and |gamma_lut| are empty they are interpreted as
  // "linear/pass-thru" [1]. If the display |is_hdr_capable_| we have to make
  // sure the |current_color_space_| is considered properly.
  // [1]
  // https://www.kernel.org/doc/html/v4.19/gpu/drm-kms.html#color-management-properties
  if (degamma_lut.empty() && gamma_lut.empty() && is_hdr_capable_)
    SetColorSpace(current_color_space_);
  else
    CommitGammaCorrection(degamma_lut, gamma_lut);
}

bool DrmDisplay::SetPrivacyScreen(bool enabled) {
  return privacy_screen_property_->SetPrivacyScreenProperty(enabled);
}

void DrmDisplay::SetColorSpace(const gfx::ColorSpace& color_space) {
  // There's only something to do if the display supports HDR.
  if (!is_hdr_capable_)
    return;
  current_color_space_ = color_space;

  // When |color_space| is HDR we can simply leave the gamma tables empty, which
  // is interpreted as "linear/pass-thru", see [1]. However when we have an SDR
  // |color_space|, we need to write a scaled down |gamma| function to prevent
  // the mode change brightness to be visible.
  std::vector<display::GammaRampRGBEntry> degamma;
  std::vector<display::GammaRampRGBEntry> gamma;
  if (current_color_space_.IsHDR())
    return CommitGammaCorrection(degamma, gamma);

  // TODO(mcasas) This should be the inverse value of DisplayChangeObservers's
  // FillDisplayColorSpaces's kHDRLevel, move to a common place.
  // TODO(b/165822222): adjust this level based on the display brightness.
  constexpr float kSDRLevel = 0.85;
  // TODO(mcasas): Retrieve this from the |drm_| HardwareDisplayPlaneManager.
  constexpr size_t kNumGammaSamples = 64ul;
  // Only using kSDRLevel of the available values shifts the contrast ratio, we
  // restore it via a smaller local gamma correction using this exponent.
  constexpr float kExponent = 1.2;
  FillPowerFunctionValues(&gamma, kNumGammaSamples, kSDRLevel, kExponent);
  CommitGammaCorrection(degamma, gamma);
}

void DrmDisplay::CommitGammaCorrection(
    const std::vector<display::GammaRampRGBEntry>& degamma_lut,
    const std::vector<display::GammaRampRGBEntry>& gamma_lut) {
  if (!drm_->plane_manager()->SetGammaCorrection(crtc_, degamma_lut, gamma_lut))
    LOG(ERROR) << "Failed to set gamma tables for display: crtc_id = " << crtc_;
}

}  // namespace ui

redpajama_set_name: RedPajamaGithub


Coinvest, an emerging startup comprised of Microsoft alumni, is announcing that it will offer a crowdsale of $30 million in COIN tokens to seed the world's first decentralized stock market for cryptocurrencies, built on blockchain technology. Crowdsale funds will be leveraged to continue the development of its products and drive the company's mission of: "Creating decentralized tools for the world to seamlessly, securely, and safely invest and use cryptocurrencies." Frustrated with the complexity, fragmentation, and quality of cryptocurrency investment options available on the market, Coinvest is determined to democratize cryptocurrencies by creating tools to: Provide mechanisms for consumers to seamlessly, securely, and safely invest and use cryptocurrencies Empower anyone to create investment vehicles for a personally curated index of cryptonized assets using one platform, one wallet, and one coin. At the core of its product portfolio is the Coinvest protocol: A blockchain protocol defining investment transactions between users and the Coinvest smart contracts. Supporting the protocol is the Coinvest DAPP. The Coinvest DAPP, empowers anyone to virtually invest in individual or a curated index of cryptonized assets through one coin. To do so, users create virtual portfolios and trade their favorite cryptocurrencies using market buy, limit buy, sell, and short orders. Orders are executed with the COIN token which are sent and held in escrow by the Coinvest smart contract. The Coinvest DAPP and smart contracts keep track of all investment data including assets, distributions, etc. Upon executing sell orders, the smart contract releases invested funds and any profits back to the Coinvest DAPP. Users can then spend cryptocurrencies directly from the DAPP using their wallet or Coinvest debit account. All transactions and funds are digitally automated by open-source computer code and are never touched or managed by any third-party.


Tent city on Independence Square in Kyiv.
Inconsistent and unsystematic approach wherefore the society fails to function, sounds the straightforward verdict on Ukrainian development by double Olympic bronze medalist Jüri Tamm in his Kiev office. With compassion, though, as the man is a great patriot of the renewed Ukraine.
58-aastane pensiopär Ljubov ei suuda kiire inflatsiooni tõttu tasuda pangalaenu.
Kui inimesed on nüüd lõpuks vabad, siis on neil lootust saada ka vabaks riigiks, ütleb üle 15 aasta Ukrainas elanud Jüri Tamm.
One-time holder of hammer throwing world record and Riigikogu member in 1999–2011, Jüri Tamm (58) is in his fifth year assisting the legendary pole vaulter Sergei Bubka lead Ukrainian Olympic Committee. Actually, for Mr Tamm Ukraine is his second home where he has lived for a total of over 15 years.
«I keep feeling that the principles used here to build the state just don't work as there just isn't the skill to build a contemporary society,» says Mr Tamm. As Mr Bubka's office manager, he's had a kind of a front row seat to the post-Maidan changes in Ukraine. This week, it was two years from the initial protest meetings.
A towering large man, Jüri Tamm spares no words describing the state of affairs in Ukraine, having pondered these for a long time.
A well-known political scientist in Kiev, Volodymyr Fesenko more-or-less shares the views of the most famous Estonian dwelling in Ukraine, as I share with him the above.
Today, anyone in Ukraine will tell you about lack of political will for genuine reforms. That is, except for the president and prime minister of course whose major mistake is still not having drawn decisively away from oligarchs. The most well-known of these – Rinat Akhmetov, Dmytro Firtash, Ihor Kolomoyskyi – are largely still in the saddle in every way. Clan politics and corruption haven't gone anywhere, the state still resembles a business project.
For the most part, reforms in Ukraine are just a mirage, on paper. Whoever has had more contacts with Ukraine, knows that in Ukraine the process has always been more important than the result. Regarding that, little has changes after the revolution.
Nothing doing, Ukraine is too vast a state (purely by area, largest in Europe with or without Crimea) and a big nation (6th in Europe by population, between Spain and Poland) to have changes come fast. The more so that it is basically a situation of war. It's an achievement in itself that the Ukrainian state has not totally collapsed and the hope is still alive among the people that the state will somehow be changed. In Ukraine, the society is currently much stronger than the state, is how an EU diplomat working in Kiev puts it nicely.
They have some few areas where reforms have been a success post-Maidan.
Firstly, it's the army of course, changed altogether beyond recognition. But the army becoming fir for battle was indeed a matter of life and death, during the Donbas war.
Secondly, the police reform carried out by Americans after the example of Georgia. In many major cities in Ukraine, the patrol and traffic police is altogether different now. The mentality of the new policemen ought to be different for the simple fact that former militia were not hired. In Kiev, people say the new policemen take no bribes.
Thirdly, life has been made a little easier for entrepreneurs. When formerly it took about a month to register a company, now it is done in a day. (Though not over the Internet as yet). The tax system has been simplified somewhat by cutting the amount of taxes and making reporting easier.
In the former USSR context, a small yet significant change is that the governmental leaders are no longer driving around accompanied by escorts bringing the traffic to standstill for hours in Kiev.
And broadly, that'll be all.
Difficult to list as reforms are these: household gas price rise three to four times; electricity price rise 1.5 times; and the doubly dearer water and heating. The prices rose, quality of services didn't.
Herewith let's consider the threefold devaluation of the purchasing power of the hryvnia since beginning of last year (then, a dollar equalled 8 hryvnias, now 24) and the 50 percent official inflation over the same period of time (in reality, however, prices have doubled if not more) as combined with minimal wage and pensions freeze.
Put together, this makes for widespread disappointment with the lack of reforms, and rapid drop of living standard.
In the park in Kiev, next to the house of parliament – a year and half ago a bloody piece of the revolution – tents are up again with people cooking food on fire.
This is the so-called tariff-Maidan which is basically to protest the manifold price rise for utilities while also uniting those unable to pay bank loans due to the rapid inflation. Indeed, the latter are the most active to protest. (Thus far), the protesters are not many, maximally a hundred or so.
The story of Lyubov (58) is typical. Four years ago, she assumed a loan of $100,000. Then, she got a dollar for 5 hryvnias. Now, the hryvnia is five times cheaper and Lyubov is a pensioner. Her pension id 2,500 hryvnias (€96) out of which she says she is only able to pay the interests but no longer the principal amount of the loan.
«I already got the letter that I will be thrown out of the apartment to cover the loan. I will show them! I'll defend my home with an automatic rifle if needed, when they come,» Lyubov almost yells at me, teary eyed yet militant.
Such now troubled dollar-lenders are about four million in Ukraine today, they tell me on the tariff-Maidan. Allegedly, tens of thousands have already been evicted.
Should the tariff-Maidan muster support by some major parties, it has the potential to grow into something serious. On the other hand, Ukrainians are visibly tired of such protests and while the nation sis still essentially at war many do not consider this morally right (even if substantiated). In Ukraine today, there is not real danger of a coup.
Thankfully, Ukraine is too vast and rich a nation to go into total decline. By nature, people are entrepreneurial and accustomed to hope in themselves, the family and friends alone. The dark site to that is that common interests for many still take the last place in the list, despite the civil society and all kinds of helps organisations mushrooming over the 1.5 years. Next to the church, the Ukrainians trust the volunteers the best, studies show.
In two years, Ukrainian GDP has dropped by over 20 percent. To find out the real living standard decline, the official statistics will sadly provide little help. Still, there's too much of the envelope salaries – even in public offices. Also in the envelopes, loads of corrupt income is still moving about, wherefore it is vain to hope serious reforms for the state apparatus to be cut. State bureaucracy simply cannot be diminished for then very many would lose their livelihood.
To illustrate the level of bureaucracy: over the 1.5 years, they have not even managed to put together a common electronic database of refugees i.e. people who had to forsake their homes due to the Donbas war.
Army and police aside, all other vital reforms are halted: decentralisation is impossible to put into laws; court reform looks like a parody; with tax reform, they just cannot make up their minds (though gradually they are being inclined towards a flat 20 percent uniform income tax); energy reform (especially with gas) touches too many influential interest groups; health and education reforms are hindered by the overly conservative views in the society, and expectations for free services.
Unlike army and police reforms, these require a relatively radical approach and come too close to the interests of the oligarchs. Also, all the above-mentioned unreformed areas are without exception sources of tremendous corruption.
Fighting the corruption is the basis for the legitimacy of the current power, as recently stated by president Petro Poroshenko chief of staff Boris Loshkin. In that case, however, legitimacy isn't too much of an issue as success in fighting corruption is nowhere to be seen.
Last fall, the party of Ukrainian prime minister Arseni Yatseniuk did win the parliamentary elections, but a year later the party's popularity was zero die to the still rampant corruption and lack of reforms, and he gave up participating with it at local elections.
As demanded by the West, Ukraine is setting up a special anti-corruption agency. The head for the several hundred strong establishment was selected almost a year ago but the bureau has still not started working! With the interest groups, they are having a tough time fighting about who will sit at the committee which will nominate these special investigators. The joke has quire angered the EU and US embassy in Kiev.
«The new anti-corruption institutions are indeed being created but for the most part these are only excising on paper as yet,» observes Mr Fesenko, the political scientist.
Another well-known political scientist Tarass Berezovets says a reason is that the oligarch-president Mr Poroshenko fears for his own interests. «The president fears that it will begin to touch the interests of his partners and friends, and of the deputies of his (party),» said Mr Berezovets.
For the main anti-corruption measure – raising the state officials salaries (for example: rank and file militia in regions get 1,800 hryvnias i.e. €70 a month!) – the state lack the money; also, this would prerequisite a broad-based public service reform which is indeed being talked about but is getting no traction.
Almost every bill in Ukrainian parliament presents a fierce fight. «Every law seems to touch somebody's interests,» says Mr Fesenko.
It was a colourful show when the parliament finally voted for the gay-friendly labour core demanded by Brussels to grant visa freedom. «Better a gay parade than Russian tanks in Kiev,» contended the presidential party. Angering the nationalists.
In the current situation of East-Ukrainian conflict and uncontrolled border with Russia is not making EU eager regarding the visa freedom. Ukraine is hoping for it to happen by the fall of 2016 – unrealistic, it seems.
To the political scientists cited, pressure by the USA, and perhaps EU, seems the best means to push the reforms for they give the financial support. They welcome the «positive intrusion» citing the successful police reform. Citing a sobering effect, they also welcome foreigners working in the Ukrainian government.
A hindrance is the differing understanding in Ukrainians what reforms are all about. An example would be land reform which they do not want: Ukrainians do not want land to be freely bought and sold. «They want rental relations,» explains Mr Fesenko.
Likewise, they are altogether reluctant regarding privatisation. As early as in 2014, the Ukrainian government promised the West to privatise state assets for 17 billion hryvnias. Till today, no privatisation competitions have been proclaimed. Meanwhile, there are some 1,800 state enterprises in Ukraine and not more than 200 might be considered strategic for the state.
The Ukrainian society is all against privatisation – based on experience, they do not believe in honesty. Rightly so: for the most part, top politicians remain the same.
An idealist, Jüri Tamm thinks that an international mega event might help – like EXPO or some title tournament. Perhaps, the nation would rally and reform around the challenge.


text:
Asian Journal | Canadian Online Newspapers
Majority of Canadians support holiday lockdown to fight COVID 19: Poll
Asian Journal
Ottawa: A new poll suggests a majority of Canadians support the idea of a lockdown on non-essential businesses and services during the holidays to fight a surge in new COVID-19 cases across the country.
Sixty-five per cent of respondents in the poll conducted by Leger and the Association for Canadian Studies said they supported a general lockdown in their province during Christmas and New Year's to tackle the pandemic versus 29 per cent who opposed the idea.
Leger executive vice-president Christian Bourque expressed surprise at the seemingly strong support, which was largely the same no matter the respondent's age or where in Canada they lived.
"I expected it to be a 50-50 type thing because we're already under some pretty severe restrictions as it is," Bourque said. "With the holidays coming up, Canadians are basically saying: `Buckle up. There's a few weeks left.' "
To that end, 51 per cent respondents believed the worst of the pandemic is currently upon the country while 29 per cent felt it is yet to come. Only 10 per cent felt the worst had past and a similar number did not know.
Those numbers perhaps reflect the continuing surge in cases, including in parts of the country that were previously almost untouched. They also coincide with new modelling from the Public Health Agency of Canada suggesting the country could top 575,000 cases and nearly 15,000 deaths by Christmas.
Despite the surge, Bourque said he would have expected the arrival of the first Health Canada-approved COVID-19 vaccine and the start of a mass-vaccination campaign this week to have created more of a sense of optimism.
"But people are saying: 'We're not there yet,' he said.
At the same time, despite the excitement surrounding the arrival of those Pfizer-BioNTech vaccine doses, attitudes around getting inoculated remained largely unchanged.
Sixty-six per cent of respondents said they planned to get a shot when it becomes available to them, which was roughly the same as when the pollsters asked the same question in previous weeks. Sixteen per cent said they had no plans to get a vaccine while 18 per cent did not know.
That suggests some continued hesitancy when it comes to the vaccine.
By Lee Berthiaume
Previous articleApproval for Moderna's vaccine 'looks positive' but a few more documents still needed
Next articleThe 2021 Prius Prime PHEV: Stellar Reputation upheld!
Feds weigh cutting COVID-19 benefit for travellers as Canada surpasses 600,000 cases
B.C. health officials urge people to avoid New Year gatherings
More cases of U.K. COVID-19 variant found in Canada
Infiniti Q50 3.0t Signature Edition: Refined Premium Sports Sedan
Volvo XC40 R Design: compact premium SUV impresses
One Cut of the Dead (PG) ****
Living up to our potential, and making sure everyone in B.C....
Google to donate $1 mn towards Indonesia quake relief
Asian Journal is a weekly English language newspaper covering both local South Asian & Canadian mainstream issues with incisive, well-balanced analysis. It also covers Chinese-Canadian / East Asian affairs.
Contact us: connect@asianjournal.ca
© 2018 Asian Journal by SW Media Group | All Rights Reserved

redpajama_set_name: RedPajamaCommonCrawl


text:
View by: Most Recent Most Popular Category: All An In-Depth CategoryC-14 dating if textilesCaucasian carpetsChinese & East Turkestan carpetsChinese artclassical carpetsIndian carpetsIslamic textilesMamluk carpetsMusée Historique des TissusMuseum collectionsottoman acrpetsQaraqalpaq textikesSafavid carpetssilk textilesSpanish CarpetsTurkish carpetsTurkmen carpetsVictoria & Albert Museum
Displaying 11-20 of 25
East Mediterranean Carpets in the V&A
The third of HALI's occasional series of in-depth articles on the carpet collections of London's Victoria & Albert Museum, on the Mamluk, Cairene Ottoman and other classical East Mediterranean types, was published in 1981 in HALI 4/1. The collection is introduced by Keeper of Textiles Donald King, and the carpets are discussed and analysed by… Read more »
Turkoman Rugs in The Victoria & Albert Museum, by Robert Pinner & Michael Franses
The first of the extended series of in-depth HALI articles on the Oriental carpet collections at the Victoria & Albert Museum, by HALI's then editors Robert Pinner and Michael Franses, with an introduction to the history of the collection by the V&A's Keeper of Textiles, Donald King, was published in HALI 2/4, 1980. To read… Read more »
The Qaraqalpaq Dialectic: Qaraqalpaqs of the Aral Delta: The Right to Reply
In HALI 175 (Spring 2013, pp.124-127), Andrew Hale reviewed David and Sue Richardson's 'encyclopaedic' new book, Qaraqalpaqs of the Aral Delta. The full version of his review was published on this site. Here the Richardsons address what they consider to be serious flaws in the reviewer's assessment. An abridged version of this detailed rebuttal appears in… Read more »
Caucasian Carpets in the Victoria & Albert Museum, by Donald King, Michael Franses & Robert Pinner
In the late 1970s and early 1980s, HALI published an occasional (and still incomplete) series of articles featuring and analysing in-depth the carpet collections at the Victoria & Albert Museum in London. The history of the collection was written by Donald King, the then Keeper of Textiles at the museum, and the rugs were analysed… Read more »
Lyon, Splendours in the City of Silk. 4: The remaining Classical Carpets, by Ian Bennett
The third of Ian Bennett's in-depth articles on the Oriental carpet collection at the Musée Historique des Tissus in Lyon, France was published in HALI 35 (1987). The article features the non-Persian holdings of 16th and 17th century classical carpets – from Spain, Egypt, Turkey, India, East Turkestan and China. To read 'The Remaining Classical… Read more »
Lyon, Splendours in the City of Silk. 3: The Safavid [Carpet] Masterpieces, by Ian Bennett
The second of Ian Bennett's in-depth articles on the carpet collection at the Musée Historique des Tissus in Lyon, France was published in HALI 34 (1987). In he discusses the remaining holdings of 16th and 17th century classical carpets from Safavid Persia at the MHT, with additional comment extracted from the writings of the late… Read more »
Lyon, Splendours in the City of Silk. 2: Ten Safavid [Carpet] Masterpieces, by Ian Bennett
In the first of his three in-depth articles on the extraordinary carpet collection at the Musée Historique des Tissus in Lyon, France, published in HALI 33 (1987) Ian Bennett discusses ten 16th and 17th century classical carpets from Safavid Persia, with additional comment extracted from the writings of the late Kurt Erdmann. To read 'Ten… Read more »
Lyon – Splendours in the City of Silk: 1. Textiles, by Georgina Adam
In the mid 1980s HALI published a series of four articles on the textiles and carpets in the collection of the Musée Historique des Tissus (MHT) in Lyons, France. The first article, by Georgina Adam, in HALI 32, focused on a select handful of the historical textiles in Lyon, the following three, by Ian Bennett,… Read more »
Caucasian 'Shield' Carpets by Michael Franses and Robert Pinner, 1978
Caucasian Shield Carpets' by Robert Pinner and Michael Franses, published in 1978 in the inaugural issue of HALI magazine, remains to this day the definitive study of these 17th and 18th century carpets with variants of the classical shield palmette design.
Imperial Puzzle: Sixteenth-Century Persian Spiral-Vine Carpets with Animals, by Christine Klose
Made possible by careful research and persistent 'detective' work, tThe late Dr Christine Klose's reconstruction of the extent of a highly regarded design type of early Safavid 'Hunting' carpets through a comparative survey of known carpets and carpet fragments.


A live-chat function will connect cardholders to a customer service representative directly for personalised and bespoke requests.
Payments provider Visa has launched a concierge mobile app to provide concierge services to its most affluent cardholders in Malaysia.
The app is a first in Malaysia, and will allow eligible cardholders to engage Visa's concierge without having to dial a hotline or type out an email.
According to Visa, the new app "offers a real-time channel for affluent consumers to arrange for services such as hotel, flight and restaurant reservations, event ticket purchases or other enquiries".
A live-chat function will also connect cardholders to a customer service representative directly for personalised and bespoke requests.
"With the introduction of on-demand apps in the market, where Malaysians become accustomed to ordering and purchasing a product or service on the go, they are used to a high level of speed and efficiency," Ng Kong Boon, Visa country manager for Malaysia said.
He also said Visa is expecting to see more affluent Malaysians use mobile app technologies to make concierge requests in future.
According to Visa, 40 per cent of the requests made to its concierge historically were travel-related, while dining-related requests were second most popular at 21 per cent.


text:
Faith, Hope and Charity: A German Look to 2015
By: Katherine Marshall
"Without faith, there is no hope, and without hope there is no future." During a December meeting in Berlin with a group of Christian development actors, German Parliamentary State Secretary Hans-Joachim Fuchtel of the Federal Ministry for Economic Cooperation and Development spoke movingly about the power of religious values to motivate people and their governments to act decisively on behalf of the millions who suffer across the world. He also set the responsibility to act squarely in the context of faith and the moral values that, his comments suggest, are inextricably linked to a religious heritage. He cited Paul, the Ten Commandments, and the example of the life of Jesus in pressing the point that religious values clearly belong in discussions about the international development agenda because faith, hope, and charity are what it is primarily about.
Germany's official focus on religion as a central factor in development strategy reflects a new willingness to explore and speak to the positive and negative roles that religious beliefs and institutions play in world affairs. Germany is not alone in this trend: particularly in Europe, it seems, country after country is stepping back and asking what religious beliefs and practices have to do with development, and how policies should take into account the growing recognition that "faith matters", however sensitive and complicated the links to the earthly topics of statecraft, foreign aid, and coming to grips with environmental challenges.
The negatives about religious roles blare forth in news reports: extremism and violence tinged with a religious aura, questions about human rights, the sufferings of religious minorities, and unease about women's equality among them. The positives have had less focus in official circles but amount to a compelling mosaic of selfless work by countless people and institutions to address individual suffering and to work for a better world. In European explorations of religious roles in development, concerns about "culture wars", above all reproductive health, have been less a lightening rod for polemical discussion than in the United States, and strategies touching on religious roles take human rights as a framework basically for granted. An exception is the recent backlash against LGBT rights in some world regions which tends to creates considerable consternation, division and tension.
Germany has long relied on an impressive array of faith-inspired organizations (Bread for the World is the umbrella organization for numerous Protestant organizations and Misereor for Catholic development organizations) for development work (they receive government funding). But the religious element of development has rarely been discussed openly.
In November 2014, The Development Ministry launched a new "Charter for the Future". It is the product of technical analysis within the ministry and an active dialogue with civil society partners. Respecting and protecting cultural and religious diversity is one of the strategy's eight pillars. Supporting religious freedom as a basic human right is linked closely to a broad understanding of development that includes action on human development, economic growth, climate change, and security.
Against this backdrop of a fresh focus on ethics, religion, and development, Berlin was a fitting place to reflect on the "state of development" and to highlight the milestone year that lies ahead in 2015. Germany celebrated in 2014 the 25th anniversary of the fall of the Berlin Wall. Remnants of the wall are a reminder of dark years of a divided nation and anti-Muslim demonstrations pose troubling current challenges. Thus past, present, and future are vividly juxtaposed. Looking ahead to 2015, the slew of planned global events put the ethical and practical challenges facing the world community in start relief. Notably, the United Nations General Assembly will meet in September to finally agree on new goals for development which will build on the Millennium Development Goals, and the Paris Climate Change summit in December will grapple with the looming challenges to the environment.
When world leaders met in the year 2000 at the United Nations, they set out challenges that they believed were worthy of the great milestone of a new millennium. Attuned to the demands for accountability, sensitive that we "treasure what we measure" and convinced that deadlines focus the mind, the Millennium Development Goals had measurable targets and deadlines. The main deadline year is 2015, now upon us. Meanwhile, global economic crisis has underscored the brittleness of the global economy, rising and often unexpected violence presents new challenges for security, and global climate "weirding" is increasingly hard to deny. The ethical imperatives that a serious discussion of religious roles and values bring into focus are needed more than ever.
Discover similar content through these related topics and regions.
Related Europe
Faith in Action tracks the activities of people of faith across the globe and across religious traditions, with a focus on development issues. Posts are originally published by the Huffington Post. Older blog posts appeared on the Washington Post's Georgetown/On Faith site.
Faith and Planning in the Sahel: Tensions and Cooperation
Sister Agatha: A Nigerian Peacemaker at Work
Thursdays in Black: Uniting Against Violence
"Paths of Peace": The Sant'Egidio Interreligious Gathering in Münster and Osnabrück, Germany
Focusing on Inclusion: Dr. Luiz Loures, UNAIDS


French firm has designed an airplane with removable wings.
It's presenting plane to Boeing, Asia to cut Europe dependence.
That's what a French entrepreneur, who's made millions by connecting engineers with industrial groups, is pitching to Boeing Co. and others. "Link & Fly" is Akka Technologies's new flagship aircraft design, with wings that come off to hasten turnover at airports and make boarding easier and closer to passengers' homes.
Plane makers have begun to react as technology companies come up with disruptive ideas — from Uber's investments in flying taxis to Kitty Hawk, a startup backed by Google's co-founder Larry Page that's creating a battery-powered single-person plane. Airbus took the offensive with a new division to oversee transport of the future, while Boeing has made a noisy foray into jetpacks.
Akka generates 75 percent of its sales in France and Germany and became more dependent on auto manufacturing with the takeover of a Daimler engineering unit about seven years ago. The Paris-based company hopes its new concept will woo new aeronautics customers in the U.S. The purchase of Texas-based engineering firm PDS Tech in June is a first step. Ricci expects the acquisition to close in three to six months.


text:
Space Policy | Blog
Scott Kelly's Historic Mission
March 4, 2016 | George W.S. Abbey
George W.S. Abbey
Senior Fellow in Space Policy
Baker InstituteBaker InstituteBaker InstituteNASANASA
Astronaut Scott Kelly's historic year-long mission at the International Space Station alongside Russian cosmonauts will lead to a better understanding of the impact of long-duration spaceflight on the human body. But it is also a lesson on how two nations can work together for the betterment of humankind, space policy senior fellow George W.S. Abbey writes.
Read "Scott Kelly mission a success story for international collaboration," published March 4, 2016, on the Baker Institute Blog.
Space Policy | Policy Brief
The Road Back to the Moon
NASA's Space Launch System
International Cooperation & Space Exploration


text:
Q: SprinBoot Authentication with both username and password Using Springboot security i need to look for user and password during the authentication phase.
In Userdatails' loaduserbyname method, I only know username.
Is there a way to be able to obtain the password and then perform the search with both the username and the password?
The database I have to authenticate with has a duplicate username but different passwords

A: The User Details are the wrong Objekt.
You have to implement a custom AuthenticationProvider. This will have access to username and password. You can use those to query the DB.
Here is an example https://www.baeldung.com/spring-security-authentication-provider.

redpajama_set_name: RedPajamaStackExchange


text:
2,700-year-old papyrus is believed to contain earliest reference of Jerusalem
TOPICS:BibleChristianityHebrewIslamJerusalemJudaismTemple Mount
Posted By: Sukanya Mukherjee October 26, 2016
An ancient papyrus fragment, recovered by the Israel Antiquities Authority (IAA), contains what is believed to be the earliest reference to Jerusalem apart from the Bible. Dating back to around 7th century B.C., and therefore older than the Dead Sea Scrolls, the document features two lines in ancient Hebrew that state:
From the king's maidservant, from Naʽarat [a place near Jericho], jars of wine, to Jerusalem.
Stolen from a cave in the Judean Desert by robbers during antiquity, the papyrus has since been recovered by Israeli authorities, and dated with the help of radiocarbon analysis. According to experts, it roughly belongs to the time when King Solomon constructed the First Holy Temple in 957 B.C. As described in the Hebrew Bible, the structure was destroyed some 400 years later during the Siege of Jerusalem by Babylonian king Nebuchadnezzar II.
Measuring around 4 inches by 1 inch, the papyrus fragment was originally a shipping document, containing records of tax payments and delivery of goods to storehouses across Jerusalem. As pointed out by historians, Jerusalem was the capital of the then kingdom of Judea. Speaking about the find, Pnina Shor, the head of IAA's Dead Sea Scroll Project, said:
It's the first time we encounter the name Jerusalem on a papyrus, which was probably written by a woman. That's very exciting.
Following its discovery, the 2,700-year-old document has been present by the Israeli authorities as evidence of the long history Judaism shares with Jerusalem, more specifically the Temple Mount. This comes on the same day that UNESCO released a document, referring to the land as a "Muslim holy site of worship". This, however, isn't entirely incorrect, since it is considered to be an important religious site in Judaism, Christianity as well as Islam. Miri Regev, the Minister of Culture and Sport in Israel, added:
The discovery of the papyrus on which the name of our capital Jerusalem is written is further tangible evidence that Jerusalem was and will remain the eternal capital of the Jewish people. The Temple Mount, the very heart of Jerusalem and Israel, will remain the holiest place for the Jewish people, even if UNESCO ratifies the false and unfortunate decision another 10 times.
In response, Saeb Erekat of the Palestine Liberation Organization was reported saying:
Contrary to what the Israeli government claims, the resolution that was voted by UNESCO aims at reaffirming the importance of Jerusalem for the three monotheistic religions, Christianity, Judaism and Islam.
Via: Seeker
14 most unusual man-made aircraft that might be confused as UFOs
Where science has failed: 7 strangest natural phenomena unexplained by science
The 8 most fascinating yet savage flesh eating plants
5 of the bloodiest ancient battles that made their mark in history
21 astounding satellite photos that exhibit accidental 'art' from above


In our staff meeting today, we were talking about various funding sources and grant proposals and what to focus on, and it just suddenly struck me how completely parallel it was to any other creature foraging for food.
Ogg make code for fire! Unh!


text:
Los Premios del Círculo de Críticos de Cine de Atlanta, es una ceremonia de premios estadounidense, con sede en Atlanta, Estados Unidos y fundada en 2017. Cada año se da la entrega de los premios para reconocer a las mejores películas del año.

Categorías de premios

 Mejor película
 Mejor director
 Mejor actor
 Mejor actriz
 Mejor actor de reparto
 Mejor actriz de reparto
 Mejor película animada
 Mejor fotografía
 Mejor documental
 Mejor elenco
 Mejor película en lengua extranjera
 Mejor banda sonora
 Mejor guion
 Premio Especial AFCC (Mejor ópera prima y Intérprete innovador)

Referencias

Premios de cine
Asociaciones de Estados Unidos
Asociaciones gremiales
Cultura de Atlanta
Asociaciones de críticos de cine

redpajama_set_name: RedPajamaWikipedia


I had always heard about the altitude sickness but had never experienced it. But this hike taught me how important it is to acclimatize and not to take altitude for granted.
Let me give you a real life example, where my porter Ashish suffered a high altitude sickness.
My guide Lal came into my room in the morning, asking if all our bags were packed. Since my friend Vijay and I were still struggling with packing, he requested us to pack them fast so our porter Ashish can take the bags and go to a lower altitude camp as quickly as possible.
Ashish was standing behind Lal and when Vijay and I inquired as to what had happened, Ashish said he had a headache. He was affected by the altitude and it was clearly visible. We tried to give him Disprins but that did not work and he wanted to throw up.
After sometime and after Ashish said he was fine, Lal asked him to head to a lower altitude camp as soon as possible and we thought that was the right thing to do. We did not see Ashish after he left from Lobuche. Lal told us that he had reached the next camp site Pangboche.
We reached Pangboche that night and we did not see Ashish anywhere. We assumed that he was resting somewhere and was feeling better.
It was still early in the morning where Lal woke us up and told us that he was going to another lower camp as Ashish was serious. He mentioned that Ashish was unconscious and his oxygen level had reached around 30.
At first we were shocked, and immediately after Lal left, we thought of two instant ideas – one is to call a rescue heli to airlift Ashish and take him to the closest hospital which is Lukla hospital (which was about 20 hours walk away from where we were) and two is to call Babu – the Managing Director of Unique Path Trekking to coordinate for the heli.
Babu immediately acted and arranged for a heli. Ashish was taken to Lukla hospital in another half an hour. There was no helipad but the heli landed in a field from where Ashish was picked up.
Note: The emergency airlift costs about USD 500 per person.
Vijay and I visited Lukla hospital to see Ashish. We spoke to the nurse and the doctor there. They informed that when Ashish arrived at the hospital, his oxygen was in 20s and they had to perform CPR to revive him. He was in emergency for nearly 7 hours.
The good news is that Ashish was revived and his oxygen had reached more than 65. He had gained his consciousness and was talking again. He will still need few more days to get back to normal but is on his way for full recovery.
And special thanks to the staff at Lukla hospital, they are doing a commendable job in helping people of Lukla and neighbouring villages. They treat porters or anyone who do not have money for free of charge. Except for the surgical treatments, they have every facility available for patients.
Ashish was lucky to have us there to help him out and save his life. But not all are as lucky as him and hence altitude must not be taken lightly. I would ask each one attempting a high altitude hike to ensure they acclimatise before going to higher altitudes.
The young boy next to me is Ashish.
My friend Vijay with Ashish.
2 replies to Acclimatisation is very important!
Proud of us 🙂 We did our bit to save a life. Happy that Ashish is recovering and is fine.
Yup cheers to both of us.


text:
Onno Kleyn (Zaandam, 12 april 1957) is een Nederlands culinair journalist en schrijver van diverse kookboeken. Het bekendst is hij van zijn columns en artikelen in de Volkskrant, waar hij een van de bijdragers is aan de rubriek "de Volkskeuken".

Biografie
Kleyn was leerling op het Zaanlands Lyceum in Zaandam. Hij studeerde een aantal jaar klassieke zang aan het Conservatorium van Amsterdam, voor hij een jaar naar Toscane vertrok, waarna hij in 1988 begon te schrijven over koken en wijn. Kleyns eerste boek was Uit eten in Frankrijk (1993). Hij heeft meer dan veertig boeken geschreven en publiceerde artikelen in vele tijdschriften. Sinds 2003 schrijft hij een receptenrubriek ("de Volkskeuken") en sinds 2006 een vaste wijnrubriek voor de Volkskrant. In 2016 verscheen zijn culinair compendium De grote Kleyn.

In 2010 begon Kleyn met het geven van schrijflessen over eten en wijn.

Met zijn dochter Charlotte Kleyn schreef hij in 2018 Luilekkerland, 400 jaar koken in Nederland, over de collectie historische kookboeken van het Allard Pierson, Bijzondere Collecties van de Universiteit van Amsterdam.

Onderscheidingen
 1997 - toekenning Wina Born-prijs voor culinaire journalistiek
 2001 - toekenning Médaille du Tourisme door de Franse overheid

Boeken
 Uit eten in Frankrijk (1993)
 Uit eten in Italië (1993)
 De smaak van Frankrijk (1994)
 Ciao Toscana (1995)
 Reiskookboek voor francofielen (1996)
 De zon in de pot - mediterrane gerechten (1997)
 Heerlijk Italië (1999)
 Eten in Frankrijk (2001)
 Heimwee naar La Douce France (2001)
 Het beste van Toscane (2001)
 Kookboek van Europa (2001)
 Lekker eten in Italië (2002)
 Heimwee naar La Bella Italia (2002)
 Kinderkookboek 'Kokkies' (2002)
 Savoir Vivre (2003)
 Olie op het Pastawater? en andere culinaire vragen beantwoord (2003)
 Open Keuken, te gast in de Nederlandse, Surinaamse, Turkse en Marokkaanse keuken (2004)
 Albert Heijn landenreeks: Frankrijk (2000), Italië (2000), België (2000), Spanje (2001), Portugal (2001), Nederland (2001), Frankrijk II (2002), Italië II (2002), Spanje II (2002)
 Reiskookboek Frankrijk (Spectrum, Utrecht 2005)
 De Volkskeuken (Meulenhoff, Amsterdam 2005), samen met o.a. Adriaan Jaeggi en Sylvia Witteman
 Reiskookboek Italië (Spectrum, Utrecht 2006)
 Culinaire Vluggertjes (Spectrum, Utrecht 2006)
 Kleyns Columns, Volkskeukens gebundeld (Spectrum, Utrecht 2006)
 Kleyns Basics, Volkskrant basiskookartikelen gebundeld (Spectrum, Utrecht 2006)
 Reiskookboek Spanje (Spectrum, Utrecht 2007)
 Italië Binnen Handbereik (Kosmos, Utrecht 2008), samen met Nathalie Bertollo, en Lydia Michiels van Kessenich
 De Volkskeuken 2 (Meulenhoff, Amsterdam 2008), samen met o.a. Pay-Uun Hiu, Marcus Huibers, Loethe Olthuis en Sylvia Witteman
 52 Weekendmenu's (Nieuw Amsterdam, Amsterdam 2010), samen met Loethe Olthuis
 Weg van Wijn (Nieuw Amsterdam, Amsterdam 2011)
 100 x Onno Kleyn, een bundel vol kookgeluk(Nieuw Amsterdam, Amsterdam 2012)
 Alle dagen wijn, scheurkalender 2013, (Interstat, Amsterdam 2012)
 Culinaire Scheurkalender 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011, 2012, 2013
 De grote Kleyn, culinair compendium (Nijgh & Van Ditmar, 2016)
Luilekkerland, 400 jaar koken in Nederland (Amsterdam University Press, 2018), samen met Charlotte Kleyn
Italië, mijn recepten en verhalen (Nijgh Cuisine, 2019)

Referenties

Nederlands culinair journalist


text:
During the 2001–02 English football season, Portsmouth F.C. competed in the Football League First Division.

Season summary
Portsmouth started the season promisingly but slumped during the winter and were involved in a relegation battle for the second half of the season. A string of poor results, including a 4–1 home loss in the FA Cup to bottom of the Football League Leyton Orient, meant that Director of Football Harry Redknapp was given more responsibilities until he eventually replaced Rix as team manager toward the end of the season. The goals of striker Peter Crouch and the creativity of veteran Croatian midfielder Robert Prosinečki played a crucial role in saving Portsmouth from relegation. Despite only spending the one season with the club before moving to Slovenian side Olimpija Ljubljana, such was the role Prosinečki played that he is now widely regarded as one of the greatest players to ever grace Fratton Park. Crouch was sold to Aston Villa near the end of the season for £5 million, which was used in the ensuing summer to rebuild the squad.

Tragedy struck the club six days before the start of the season when goalkeeper Aaron Flahavan was killed in a car crash near Bournemouth on 5 August. Both Portsmouth and Flahavan's youth club Southampton retired the number 1 jersey during the season, out of respect for Flahavan, who had played more than 100 games for Portsmouth since making his debut five years earlier.

Kit
Portsmouth retained the previous season's kit, manufactured by the club's own brand, Pompey Sport, and sponsored by Bishop's Printers.

Final league table

Results summary

Results by round

Results
Portsmouth's score comes first

Legend

Football League First Division

FA Cup

League Cup

Squad

Left club during season

References

Portsmouth F.C. seasons
Portsmouth