text:
\section{Introduction}

The pre-amorphization of silicon by high dose ion implantation is one of the identified processes for the realization of the ultra-thin junctions of the technological nodes 65 nm and below of the silicon microelectronics industry. The transformation of crystalline (c-Si) into amorphous silicon (a-Si) on a layer close to the surface reduces the channeling of the dopant consecutively implanted. Such a technological stage is therefore required to limit the penetration into the substrate of small radius atoms such as boron, the standard $p$ dopant in microelectronics \cite{Tsaur83,Seidel85}. The pre-amorphization and the dopant implant might be followed:

\begin{itemize}
\item by an annealing at a temperature low enough ($<$ 700 $^{\circ}$C) to recrystallize the amorphous layer and activate the doping, but insufficient to cause a significative diffusion of the dopant. Reference \onlinecite{Timans04} gives such an example, with a depth of the junction at 10$^{18}$ cm$^{-3}$ of $[$16-19$]$ nm compatible with the values $[$10-19$]$ nm targeted by the ITRS roadmap \cite{ITRS}. Likewise, the high level of activation allows to reach sheet resistances of $[$405 -785$]$ $\Omega/\square$ to compare with the range $[$760-830$]$  $\Omega/\square$ of the ITRS Roadmap.
\item by an annealing at very high temperature (laser or spike annealing). In the case where the melting temperature of a-Si is reached, the profile after annealing has an ideal ``square-like" shape as the diffusivity of the dopant is higher in the liquid than in the crystal. An example of such a profile is given in the reference \onlinecite{Hernandez03}.
While ideal for a full wafer implantation, this solution however is not always compatible with the other technological stages \cite{Lindsay03}. The other alternative is to anneal just beneath the melting temperature (ex : 1300 $^{\circ}$C) during a very short duration (ex : spike of 330 $\mu$s wide at 1250 $^{\circ}$C) to limit the dopant diffusion \cite{Fiory99}.
\end{itemize}

In the two cases, it is critical to have a good understanding of the recrystallization process of the amorphous layer to develop such technologies. If, on the one hand, the recrystallization velocity by solid phase epitaxy (SPE) of an amorphous layer is well known from experiments in the intrinsic case \cite{Olson88}, this is not the case in presence of impurities where accelerations, slowdown, compensation and even hysteresis are observed \cite{Olson88}. Moreover in this case, the final distribution of the dopant is intimately related to the velocity of recrystallization. Now, this case of doped a-Si is precisely of current interest for the formation of junctions. In the absence of an experimentally established law, is it possible to calculate at the atomic level the recyrstallisation velocity of doped a-Si ? Atomistic simulations of a-Si, of its interface with c-Si and of its recrystallization have already been published \cite{Caturla94,Caturla96,Bernstein00,Motooka00,Motooka01,Humbird02,Marques03,Mattoni04}. However in these works the atomistic simulations of the recrystallization of a-Si are not always exploited to extract the recrystallization velocity $v_\mathrm{cryst}$. The comparison with experiments is most often limited to the activation energy of $v_\mathrm{cryst}$. Moreover, the description of silicon by means of empirical interatomic potential is not unique and the question of the most adapted one(s) for this particular case is still open. The aim of this paper is to present a systematic study of the recrystallization velocity as a function of the annealing temperature for the various interatomic potentials available for silicon. The present work has been devoted to the intrinsic case, that already appears an issue by itself.

In this paper, we begin by a presentation of the method of simulation we have used to model the a-Si, its recrystallization and the extraction of the recrystallization velocity. The results are then presented for five different interatomic potentials in the second part. In the last part, the wide differences obtained as a function of the interatomic potential are analyzed and an explanation is proposed based on a possible transformation of the amorphous layer into a liquid one.

\section{Method}

This section is first devoted to a discussion about the different empirical interatomic potentials used in the molecular dynamics simulation. Next, the description of the method  used to build the a-Si cluster and to its properties is presented. The generation of the a-Si/c-Si structure is also reported. Finally, the simulation of the recrystallization of a-Si on c-Si with molecular dynamics  is described. The systematic exploitation of these atomistic simulations to determine the recrystallization velocity is also explained in details.

\subsection{Molecular dynamics using interatomic potentials}

In this article, the annealing of the a-Si on c-Si stack was investigated by means of molecular dynamics simulation employing empirical interatomic potentials. Interatomic potentials are an efficient way to describe the interaction between atoms using a continuous and derivable functional of the atomic positions. As they do not contain deep physical effects as in ab-initio description, their domain of validity is not universal. Most often, interatomic potential are developed on a particular application such as the study of surfaces or the description of a phase transition. Five empirical potentials developed for silicon were tested in this study : the Stillinger-Weber potential in its original parametrisation \cite{SW} and in a recent parametrisation called SW115 \cite{SW115} designed for a better description of the melting of a-Si and c-Si, the third formulation of the Tersoff's potential \cite{Tersoff}, the Environment Dependent Interatomic Potential (EDIP) \cite{EDIP} and the Lenosky's pontential \cite{Lenosky}. To our knowledge, these are the main potentials used in the literature to describe silicon. The 4 functional forms (Stillinger-Weber and SW115 have the same formulation) contain an attractive and a repulsive part given in the form of continuous functions of the relative distance between pairs of atoms, with a two-body and a three-body character, respectively. These functional forms are adjusted to reproduce the $T=0$ equilibrium crystalline structure, cohesive energy, elastic constants and possibly other structural or energetic parameters of crystalline Si. The Stillinger-Weber potential has a three-body term that imposes the angle $\theta$ between the three neighbors to $\cos\theta = -1/3$ and therefore strictly enforces the diamond structure. The EDIP potential is inspired from the Stillinger-Weber potential, but it adapts to the coordination (4, 3, 2,...) of the atom and it is therefore more general. The formulation of the Tersoff potential is slightly different from the two previous ones, and has the form of a pair potential with a bonding strength that contains the dependence upon the local atomic environment. Finally, the Lenosky is a modified embedded-atom method including a pairwise embedding functional and an angular term. Which potential should be more adapted to our case is not obvious a priori. Therefore simulations with these 5 different potentials were performed.

\subsection{Amorphous cluster}

Amorphous silicon in silicon devices is created by ion implantation of heavy ions. Ideally, the best approach would be to mimic the experiment and therefore to simulate the ion implantation. However, it is not currently realistic since the simulation of the implantation of an ion and of all the interactions and collisions with the atoms of the target by molecular dynamics is already computer resources consuming, and many events of that kinds should be simulated to obtain an a-Si layer of good quality. The other alternative is to construct a cluster of amorphous silicon and to glue it on crystalline silicon. The main two methods to form an amorphous structure starting from the crystal are a) the disordering of tetrahedral interatomic bonds by the method of Wooten, Winer and Weaire (WWW)\cite{Wooten85} and its derivatives \cite{Barkema00,Valiquette03} and b) the simulation of an idealized a-Si, obtained by a melting followed by a quenching to a solid but amorphous state \cite{Luedtke89,Ishimaru97}. We will call this second method the ``melting-quenching". Each of these two methods has its advantages and drawbacks. The main disadvantage of the WWW method is to enforce a tetravalent coordination, while it is experimentally known \cite{Coffa93} that a-Si contains defects which may be floating or dangling bonds. The simulation of the melting-quenching on the other hand, done using a molecular dynamics simulation with an empirical potential, relies first on the ability of the potential to correctly describes a liquid at elevated temperature, and second to correctly describe the amorphous structure upon quenching, which is not unconditionally ensured for neither of these two aspects as emphasized later (see Section \ref{Discussion}).

In the present work, the results are obtained with a WWW a-Si. The reason for this choice is first to construct an amorphous cluster of good quality, and next paragraph will discuss of this point. Moreover, the objective was to test which of the numerous empirical interatomic potential developed to model silicon \cite{SW,Tersoff,EDIP,SW115,Lenosky} is the more adapted to keep the amorphous structure and to give the recrystallization velocity measured by solid phase epitaxy experiments \cite{Olson88}.  Using the melting-quenching method would have required to construct for each potential its corresponding amorphous cluster, which, while more rigorous than the use of a unique WWW amorphous cluster, would have introduced different amorphous structures. Therefore all the results presented in the section \ref{SectRes} have been obtained with the same initial a-Si cluster constructed by the method presented just below. On the other side, we believe that, once the choice of the most adapted interactomic potential has been made, the better approach should on the contrary be the simulation of the melting-quenching-recrystallization with this potential.

\subsubsection{Construction}
The WWW \cite{Wooten85} a-Si structure is obtained using an algorithm of bond switching between pairs of first neighbours. The total energy associated to this bond reordering is originally calculated using a Keating potential \cite{Keating}. A Maxwell-Boltzmann probability is then determined with this energy and a  temperature. In this way, an elevated value of the temperature can be used at the beginning of the amorphisation to strongly disorder the structure, and be subsequently decreased to reduce the number of defects in order to obtain a very realistic a-Si. This procedure was applied to an initial cluster of 4096 atoms of c-Si.

\subsubsection{Properties}

The current paragraph presents the properties of the WWW a-Si cluster of 4096 atoms and the comparison with published experiments.

The side of the initial cubic cluster of c-Si is of $L_\mathrm{c-Si}$=43.44 \AA. The density before amorphisation is therefore equal to $d_\mathrm{c-Si}$=$4096/L_\mathrm{c-Si}$ = 0.0500 at/\AA$^3$. After amorphisation, the dimensions of the cluster are slightly reduced: $L_\mathrm{a-Si}$=43.38 \AA. The density is therefore 0.4\% higher ($d_\mathrm{c-Si}$=0.0502 at/\AA$^3$). This feature is in disagreement with experiments where a reduction of the density
    of approximately 1.8 \% has been measured \cite{Custer94}. This difference might be due to the dilatation and to the strain induced by the implantation at high dose and high energy ($>$ MeV) used in the experimental articles \cite{Volkert91}, both effects neglected in the model. It is not obvious to simulate these macroscopic effects at the atomic level. Moreover, it is not sure that this rather slight difference is significative of a problem in the model.

The angular distribution of the bonds between first neighbours is shown in Fig. \ref{FigAngDist}. The mean angle of the distribution is equal to 109.1$^\circ$ and the standard deviation is equal to 10.6$^\circ$, in excellent agreement with the work of Djordevic et al.\cite{Djodjevic95}.

The pair correlation function $g(r)$, i.e. the probability to find an atom between the spheres of radius $r$ and $r+dr$ centered on any atom is given in Fig. \ref{FigRadDist}. $g(r)$ is calculated using the radial distribution $G(r)$~:
\begin{equation}
g(r)=\frac{G(r)}{4\pi r^2 \rho_{0}}
\label{EqPCF}
\end{equation}
where $\rho_{0}$ is the density of c-Si. The radial distribution is the number of neighbours at the distance $r$~:
\begin{equation}
G(r)=\frac{1}{N}\sum_{i,j} \delta(r-|R_{i}-R_{j}|)
\label{EqRadDis}
\end{equation}
where $|R_{i}-R_{j}|$ is the distance between atoms $i$ and $j$ and $N$ the total number of atoms. The abscissa of the maxima of the pair correlation function (see Fig. \ref{FigRadDist}) corresponds to the distances between first (2.35 \r{A}), second (3.83 \r{A}), third (5.43 \r{A}) and even fourth (6.62 \r{A}) neighbours. The peaks are of course enlarged due to the disorder in a-Si compared to c-Si, but at least three peaks are clearly distinguishable and the first and second peaks are clearly separated, with a gap to $g(r)$=0 between the two peaks. The pair correlation function is not directly comparable to experiments. Therefore its Fourier transform was calculated to extract the structure factor $S(Q)$, given in Fig. \ref{FigFactStruc}. The shape, the position and the intensity of the peaks is in perfect agreement with the structure factor measured by Laaziri et al. \cite{Laaziri99,Laaziri99_2} on a-Si obtained by ion implantation, except a slight underestimation of the intensity of the first peak. This agreement is significative of the good description of the local order in the WWW a-Si.

To conclude, although the discrepancy on the density, the WWW a-Si has excellent geometrical characteristics and the structure factor is in good agreement with experiments. Therefore the quality of the a-Si structure is adapted to the objective of this study.

\subsection{Construction and properties of the a-Si/c-Si structure}

The resulting amorphous cluster of 4096 atoms (43.38 \AA~ each side) was then truncated  and glued along the [100] surface  of the c-Si cell to form the interfacial structure \cite{Mattoni04, Brambilla00, Motooka00}. The  structure contains  1905 atoms and the crystal part  of the interfacial structure  corresponds to  50\% of the global thickness. It has been observed that the crystalline thickness  is an important factor since it appears in some cases that a recrystallization of the a-Si layer was obtained for the bigger structure while the disorder propagated in the c-Si part of the smaller structure (21\% of the global thickness)  although the two atomic layers at the bottom of the structure were frozen at their perfect diamond lattice site to eventually compensate the thin thickness of the crystalline part. Tests on  bigger stack (8034 atoms) did not give significantly different recrystallization velocities than with the stack of 1905 atoms. Since the computational time is drastically increased for this stack of 8034 atoms, we dropped it and focused the work on the 1905 atoms interfacial system. Table \ref{table:interface_coordination} presents the mean coordination number and the silicion defects distribution of the initial interface. The statistics have been estimated for all the silicon atoms located at less than 2.35 \r{A} of the  interface both for the cristal and the amorphous part. A cut-off distance of 2.7 \r{A} has been used to calculate the first neighbours. Large amount of threefold and twofold silicons defects are present initially due to the difficulty to perfectly align an amorphous interface and a perfect crystal.

In order to improve the interface quality, prior to the main recrystallisation step, an equilibration step has been  assumed. An objective is  to relax the interface  and to reach the temperature targeted value for the main recrystallisation simulation.  Periodic boundary conditions only along the lateral directions have been used allowing the system  to relax along the regrowth direction.  The equilibration phase is performed during 4 ps at the targeted temperature value using a 2 fs time step for the velocity Verlet algorithm.  During this equilibration, the temperature is imposed by the scaling of the velocity which ensures an efficient convergence of the temperature as shown in Fig. \ref{FigTemp}. The empirical atomic potential used in this  pre-annealed step is identical to the one used for the recrystallisation simulation. Table \ref{table:interface_coordination} presents the evolution of the mean coordination number distribution for the different interatomic potentials. First of all, it has been checked  that during this equilibration step, no real recrystallisation occurs (the interface variation  is less than 0.4 \r{A} for all the  inter-atomic potential). The equilibration step improves the quality of the interface since the fraction of fourfold silicon atoms is  enhanced for almost all interatomic potentials. On the other side, the choice of the interatomic potential has a clear influence on the defects at the interface even for a very short annealing. After equilibration, both Tersoff and SW115 tend to favorize the presence of threefold defects. On the other side, fivefold silicon atoms are the most dominant defects  with the SW, EDIP and Lenosky potentials.

\subsection{Recrystallization of the amorphous layer}

The recrystallization of the amorphous layer has been simulated  after the equilibration step in an second step where a Nos\'e-Hoover thermostat \cite{Nose-Hoover} is applied. The acquisition begins  during a number of time steps sufficient to observe the recrystallization of all or of one a part of the a-Si layer. During this phase, the positions of the atoms are saved to allow a post-treatment explained in the following part. The interval between two backups is adapted to the speed of the recrystallization : from 10 ps to 1000 ps. Once the simulation has ended, i. e. the amorphous layer is partially or totally crystallized, the positions stored during the simulation are exploited to extract the recrystallization velocity. Several methods have been used in the literature to quantify the motion of the recrystallization front. Bernstein et al. \cite{Bernstein00} classify the atoms as ``crystalline" or ``amorphous" on the basis of a geometric criterion called $\chi$ and equal to the sum of the absolute values of the dot products between bond directions around each atom and the bond directions in the underlying crystal lattice. This parameter $\chi$ is equal to 4 in the crystal and 2.7 in the a-Si. The velocity of recrystallization is extracted from the number of crystal atom versus time. Marqu\'es et al. \cite{Marques03} extract the velocity in atom/ps from the slope of the potential energy curves, since the recrystallization is accompanied by a decrease of this energy. Motooka et al. \cite{Motooka00} only specify that the a-Si/c-Si interface is defined as a middle of their rough interface, without additional information on a criteria used. Albenze et al. \cite{Albenze04} define an order parameter equal to 1 in solid, 0.7-0.8 in an amorphous state and 0.2-0.4 in liquid, from the angles between each atom and its first neighbours. Next, the sample is divided into slices, and the parameter is calculated inside each slice which is consecutively classified into one of the three states. This method helps to follow the displacement of a crystalline/amorphous interface. In our opinion, the most rigorous analysis is made by Mattoni and Colombo \cite{Mattoni04}. They calculate a structure factor along the growth direction $S(z)$ that simply quantify the crystalline order in 2D slices in the $z$ direction. This structure factor is equal to 1 when the plane is ordered (case of a crystal at 0 K) and around 0 when the order is lost. A detection of $S(z)$ = 0.5 is used to easily place the a-Si/c-Si interface and further deduce the recrystallization velocity. The same criterion has been used to extract the recrystallization velocity from our simulations. Fig. \ref{FigSz} gives an example of structure factor for a stack of 8034 atoms. The structure factor along the growth direction is aligned with the representation of the atoms to emphasize the link between order/disorder and the value of $S(z)$. The interface position obtained at $S(z)$ = 0.5 is reported versus time in Fig. \ref{FigFitInterface}. Until $\approx$ 240 ps, the position increases linearly with time : the disordered layer recrystallizes at a roughly constant velocity. After 240 ps, the position saturates, the whole layer has recrystallized. The velocity of recrystallization is estimated from the fit of the linear region (see Fig. \ref{FigFitInterface}). In this particular case, a value of 0.015 nm/ps was found. This procedure is applied to 50 to 100 files of 1905 atomic positions, for 4 to 6 temperatures for each of the 5 potentials. The evolution of the a-Si on c-Si was studied up to $\approx$ 100 ns for the slowest cases, a computer job of two months.

\section{Results and comparison with published simulations}
\label{SectRes}

The results of our molecular dynamics simulation of the recrystallization of an a-Si on c-Si stack are presented in Fig. \ref{FigVelCalc} for the Stillinger-Weber, Tersoff, EDIP, SW115 and Lenosky potential. This figure evidences a strong dependence of the velocity of recrystallization on the interatomic potential. At 1200 $^{\circ}$C, there is for example 4 orders of magnitude separating the results with the Stillinger-Weber potential from the results with the Tersoff potential. These differences might also be even more pronounced at low temperature, but the limit of our simulations at time being is 2$\times$10$^{-6}$ nm/ps (one monolayer recrystallized after 100 ns) and does not allow to get additional points for the Tersoff potential.

Very few data are available in the literature to perform a comparison with our calculations. As for the Stillinger-Weber potential, the only point to our knowledge can be deduced from Fig. 1 of Mattoni and Colombo \cite{Mattoni04} : at 1200K, we have estimated a velocity of $\approx$ 2$\times$10$^{-3}$ nm/ps. However, their calculation was made i) on a system obtained by melting-quenching with the Stillinger-Weber potential, although this procedure is known to give an amorphous layer of poor quality \cite{Broughton87} and ii) including B atoms in the Si lattice to study their clustering upon annealing. It is known that dopant atoms modify the velocity of the recrystallization \cite{Olson88}. The direct comparison with our calculations would therefore not be conclusive, although the order of magnitude is roughly comparable (around 10$^{-2}$ nm/ps in our case versus the value of 2$\times$10$^{-3}$ nm/ps in the paper of Mattoni and Colombo \cite{Mattoni04}).

Concerning the simulation of the recrystallization with the Tersoff potential, the velocities calculated by Marqu\'es et al. \cite{Marques03} in atom/ps is not useful for the comparison with our simulations. Motooka et al. \cite{Motooka00} give the velocity as a function of the inverse temperature. Their results are reported in Fig. \ref{FigCompSimu}. Their simulations with an a-Si system obtained by melting-quenching give two regimes, a low temperature regime with an activation energy of 2.6 eV and a high temperature regime with an activation energy of 1.2 eV. On the contrary, experiments give an Arrhenius behavior from 470 to 1350 $^{\circ}$C with a single activation energy of 2.68 eV \cite{Olson88}. We do not observe these two regimes, but a single one with an activation energy of 2.99 eV. Nevertheless, our results are in perfect agreement with the results of Motooka et al. in the low temperature regime (see Fig. \ref{FigCompSimu}).

Bernstein et al. \cite{Bernstein00} have published a figure of the recrystallization velocity as a function of the inverse temperature between 700 and 1100 K for the EDIP potential. They also obtained two regimes. The low temperature regime ( $<$ 950 K) has a very low energy of activation (0.4 eV) \cite{Bernstein98}. The regime at high temperature has an activation energy of $\approx$ 2.0 eV. The fit of their points in this regime is given in  Fig. \ref{FigCompSimu} together with our results. Our result is 3 times higher at 1100 K  and the difference increases when the temperature decreases. However a  direct comparison is difficult since different methods have been used. For example,  the velocity of recrystallization is calculated by identification of the ``crystal" and ``amorphous" atoms, not with a structure factor. Moreover the amorphous part of the atomic structure is generated by a procedure of melting-quenching.

To our knowledge, there are no published values for the SW115 and Lenosky potentials.

To conclude, the comparison between our simulations and the literature is difficult. Many differences exist in the method to generate the amorphous layer or to estimate the interface position. However it can be noticed a relatively good agreement with the simulations of Motooka et al. \cite{Motooka00} for the low temperature regime.

\section{Discussion}
\label{Discussion}

Although the results of the simulations presented in Fig. \ref{FigVelCalc} seems at first glance very disparate, a deeper analysis allows to regroup them under two categories. The first category is made up of the results obtained with the Tersoff and SW115 potentials. Both interatomic potentials give an Arrhenius behavior and smaller values of the velocity of recrystallization. The second category includes the Stillinger-Weber, the EDIP and the Lenosky potential. Using these three potentials, the velocity of recrystallization does not follow an Arrhenius law any more but presents a maximum followed by a decrease of the velocity at high temperature. Moreover, the values of the velocities are higher in this second case. In this section, we firstly compare the results of each category with the measurements of the recrystallization velocity in the case of a SPE and LPE (Liquid Phase Epitaxy) respectively, before presenting an analysis of the order parameter and melting temperatures to evidence SPE in the first category and LPE in the second.

\subsection{Comparison with experiments}
The first category of results, obtained with the Tersoff and SW115 potentials, is characterized by an Arrhenius behavior similarly to the numerous measurements of the velocity of recrystallization of a-Si on c-Si reviewed by Olson and Roth \cite{Olson88}. Fig. \ref{FigFitTersoffSW115} presents the experimental results of Olson and Roth, our simulations with the Tersoff and SW115 potential and their fits. The activation energies are 2.99 eV for Tersoff and 1.87 eV for SW115. Not only the activation energy obtained with the Tersoff potential is close to the value of 2.68 eV obtained by measurement, but also the absolute value of the velocity. As for the SW115, the behavior is globally similar, although the recrystallization is accelerated in comparison to the experiments, especially at low temperature (lower activation energy).

The second category includes the Stillinger-Weber, the EDIP and the Lenosky potentials. These three potentials have in common higher values of the velocities, up to 0.02 nm/ps i.e. 20 m/s. These results are orders of magnitudes far from the law of Olson and Roth \cite{Olson88}, they don't seem to have anything to do with the phenomenon measured by these authors. However, velocities of m/s are typical of the recrystallization of silicon melted by pulse laser \cite{Galvin85} and of explosive recrystallization of a-Si during pulsed laser irradiation \cite{Thompson84}. In both cases, the speed of the recrystallization is governed by the transformation of liquid silicon (l-Si) into c-Si. In the case of explosive recrystallization of a-Si, the liquid is formed at the a-Si/c-Si interface due to a local heating by the release of heat generated by the transition from a-Si to c-Si \cite{Thompson84}. The speed of crystallisation of l-Si has been measured by Galvin et al. \cite{Galvin85}. These measurements are presented in Fig. \ref{FigSWExpFit} together with the results obtained with the Stillinger-Weber potential. The simulations at high temperature are in excellent agreement with these measurements. Moreover, the transition-state theory of crystal growth gives the following expression for the velocity of recrystallization \cite{Kluge89}:
\begin{equation}
v(T)= C\exp \left(-\frac{Q}{kT}\right)\left(1-\exp\left(-\frac{L(T_0-T)}{kT}\right)\right)
\label{EqVelLiqu}
\end{equation}
where $Q$ is the activation energy for viscous or diffusive motion in the liquid, $L$ is the heat of fusion of the phase transformation, $T_0$ is the equilibrium melting temperature and $C$ is a constant. Our simulations were fitted to this law, and Fig.  \ref{FigSWExpFit} shows that an excellent adjustment can be obtained with $T_0$ = 1600 K and $Q=$ 0.54 eV. The results obtained with the EDIP and Lenosky potentials can also be perfectly calibrated with Eq. \ref{EqVelLiqu}, but the agreement with experiments is less good in these two cases : EDIP gives a slower recrystallization, and Lenosky is shifted towards smaller temperatures.

The conclusion is therefore that the recrystallization velocities obtained with the Stillinger-Weber, EDIP and Lenosky potentials are very different of the results obtained for a solid phase epitaxy, but on the other hand they are typical from the solidification of a liquid. The question is now on the origin of this behavior, since the initial system is indeed an a-Si / c-Si stack, and not a l-Si / c-Si stack. This problem is studied in the following section.

\subsection{Analysis : SPE versus LPE}

In order to analyze in more details the structure of the initial a-Si layer upon annealing, we have calculated the order parameter defined by Albenze et al. \cite{Albenze04}. First the parameter called $A$ is calculated for each atom:
\begin{equation}
A=\sum_i \left(\cos\theta_i + \frac{1}{3} \right)^2
\end{equation}
where the sum is performed on the 4 nearest neighbors of the atom and $\theta_i$ is the angle made by each triplet. $A$ to classify the atom as a solid-like ($A<0.4$) or a liquid-like ($A>0.4$) one. Consecutively, the structure under study is cut in slides, and the percentage of solid-like or liquid-like atoms is calculated in each slide. This order parameter is close to 1 in a crystal, around 0.2-0.4 in a liquid, and around 0.7-0.8 in an amorphous material. The order parameter as a function of $z$, the direction perpendicular to the disordered Si/c-Si, is represented for a simulation at 1273 K with the Stillinger-Weber potential (Fig. \ref{FigOPSW1273}) and at 1673 K with the Tersoff potential (Fig. \ref{FigOPT1673}). Fig. \ref{FigOPSW1273} clearly demonstrates that the disordered silicon for $z>30$\AA, while amorphous at the origin, transforms to a liquid during the initial equilibration stage. When the simulation of the annealing proceeds, the interface moves towards the right, as the recrystallization occurs, and the disordered part remains liquid. On the contrary with the Tersoff potential, the order parameter remains in the range $[$0.6-0.8$]$ during all the process of recrystallization. This is a first proof that the a-Si initially constructed is transformed into l-Si when the Stillinger-Weber potential is used, while it remains amorphous with the Tersoff potential.

One could argue that these differences of behavior are due to the ability of the interatomic potentials to correctly predict the experimental melting temperature of a-Si. Indeed, the melting temperature of a-Si, $T_\mathrm{m}^a$, is measured in the range $[$1420-1530$]$ K\cite{Thompson84,Donovan83}. However, the Tersoff potential is known for its large overestimation of the melting temperature, for c-Si as for a-Si : Marqu\'es et al. \cite{Marques04} have determined a value of that the melting temperature of $T_\mathrm{m}^a$ = 2050 K, while for the Stillinger-Weber potential, a value of $T_\mathrm{m}^a$ = 1400 K was found by Brambilla et al. \cite{Brambilla00} and 1075 K by Albenze et al. \cite{SW115}. Indeed, Fig. \ref{FigOPSW(T)} shows that the temperature used with the Stillinger-Weber potential must be decreased to $[$473-673$]$ K to keep an order parameter of the amorphous kind after the initial equilibration stage. Therefore we think that not only the melting temperature enter into account but more globally the ability of the potential to handle or not an amorphous structure. The Stillinger-Weber potential clearly favors the liquid state, as already observed in the literature \cite{Broughton87}.

In order to further corroborate the transformation to a liquid state, the radial and angular distribution of the atoms have been calculated in the disordered layer after the equilibration stage. The results are respectively presented in Fig. \ref{FigRadDistrEqu} and \ref{FigAngDistrEqu}. After a simulation with the Tersoff and SW115 potentials, the typical characteristics of an amorphous material are preserved: distinct peak of the second neighbours with a gap between first and second neighbours, and angular distribution comparable to the initial one (WWW a-Si). With Stillinger-Weber, EDIP and Lenosky on the other hand, there is no gap between the peaks of the first and second neighbors in the radial distribution (see Fig. \ref{FigRadDistrEqu}), these second peak being even much less pronounced. Moreover, the angular distribution is drastically smeared out (see Fig. \ref{FigAngDistrEqu}). All such structural features are far more typical of a liquid \cite{Waseda75,Stich89}.

Consequently, our understanding of MD simulations of the recrystallization of a-Si using empirical potentials is the following. The Tersoff and SW115 potentials are adapted to the description of the SPE. The amorphous character is preserved with these potentials and the velocity of recrystallization follows an Arrhenius law as observed experimentally. The SW115 potential gives however a recrystallization velocity two orders of magnitude faster than the experiment. The Tersoff potential gives an excellent agreement with the law of Olson and Roth\cite{Olson88}. Its drawback is its excessive value of the melting temperature (for a-Si as for c-Si). We have tried to apply a simple rescaling of the temperature $T_\mathrm{rescaled} = T_\mathrm{simu} \times T_\mathrm{m,exp}^c/T_\mathrm{m,simu}^c$, $T_\mathrm{simu} \times 1685/2400$ in the case of the Tersoff potential. This approach is not satisfying since the simulation has moved away from the experiment by nearly 4 order of magnitudes as shown in Fig. \ref{FigTempNorm}.

The Stillinger-Weber, EDIP and Lenosky potentials are not adapted to the simulation of the SPE of a-Si. These three potentials seem to have a tendency to transform the amorphous structure into a liquid one, even below the nominal bulk melting temperature. Nevertheless, the resort to the Stillinger-Weber potential is perfectly justified to simulate the LPE, the experimental results obtained by pulse laser annealing \cite{Galvin85} being in the margin of incertitude of our simulations. The sluggish behavior of the EDIP potential, already mentioned by Albenze and Clancy \cite{Albenze05}, is due to its formulation developed to handle non-tetrahedral environments. This environment dependency is a disadvantage for this particular problem, the return to the crystal arrangement is not enough enforced. Finally, the Lenosky potential is also a good candidate for the simulation of LPE if the temperature is scaled to account for the differences in metling temperatures (see Fig. \ref{FigTempNorm}).

\section{Conclusion}

The recrystallization of an amorphous silicon layer on a crystalline silicon substrate has been simulated by means of molecular dynamics. The initial a-Si on c-Si stack has been constructed by the WWW method and the structural properties of the resulting amorphous were carefully analyzed to validate the atomic arrangement in the structure with respect to the available experimental results. Subsequently, the annealing of this amorphous-crystal stack was studied using five of the most widely used interatomic potentials for silicon. A systematic campaign of molecular dynamics simulations as a function of temperature in the appropriate interval to observe amorphous recrystallization was carried out to extract the velocity of recrystallization versus the temperature.  A wide disparity is obtained as a function of the interatomic potential, underscoring the limitations of the different empirical potentials that are not able to treat with an equivalent and consistent degree of accuracy the three Si phases of interest in the technological process (diamond crystal, amorphous and liquid). A similar shortcoming had been already pointed out by Ding and Andersen \cite{Ding86} for the case of germanium. However, the results can be classified in two categories. The first category is the expected solid phase epitaxy of the a-Si, obtained with the Tersoff and SW115 potentials. The second category corresponds rather to a liquid phase epitaxy as obtained with the potentials of Stillinger-Weber, EDIP or Lenosky, due to the transformation of the starting a-Si cluster into a liquid one. The reliability of the empirical potential molecular dynamics compared to experiments is shown to be very good, provided that a suitable potential is chosen to investigate each different phenomenology. Based on  the results of the present study, the best candidates turn out to be Tersoff for the SPE and Stillinger-Weber for the LPE.

\section{Acknowledgements}
This work is part of the common laboratory STMicroelectronics/IEMN supported by the MINEFI. The numerous computer simulations would not have been possible without the reliable park of workstations managed by Jean-Michel Droulez. The authors thank W. Windl for the suggestion to look at the Lenosky potential and Guy Allan for  discussion about the amorphous cluster.

\newpage

redpajama_set_name: RedPajamaArXiv


text:
O voo Aeroflot 593 era uma linha aérea da companhia russa Aeroflot, ligando Moscou a Hong Kong. No dia 23 de março de 1994, um Airbus A-310 que realizava essa rota caiu sob circunstâncias suspeitas, a 20 km a leste de Mejdurechensk. A queda da aeronave causaria a morte dos seus 75 ocupantes. As investigações levariam a descoberta de um dos mais bizarros acidentes aéreos da história.

Aeronave

O Airbus A-310-300 destruído no acidente foi fabricado em 1991, tendo realizado seu primeiro voo em setembro de 1991. A aeronave seria adquirida pela companhia nacional francesa Air France, onde recebeu o prefixo F-WWCS. Cerca de um ano depois, a Air France alugaria cinco A-310-300 para a Aeroflot, entre elas o F-WWCS , que seria rematriculado como F-OGQS. A empresa russa iria empregar a aeronave, batizada de Glinka, nas ligações entre a Ásia e a Europa, através da sua subsidiária Aeroflot - Russian Airlines.

Acidente

Após ter decolado de Moscou com destino a Hong Kong, realizando o Voo Aeroflot SU 593, com 10 horas de duração, o Airbus A-310-300 sobrevoava o sul da Sibéria quando subitamente mergulharia rumo ao solo na madrugada de 23 de março, onde atingiria um morro de 600 m. Com o violento choque, a aeronave explodiria, espalhando destroços por uma região de floresta a 20 km a leste da cidade de Mejdurechensk.

Após a falta de comunicação do voo 593, o ATC (Controle de tráfego aéreo) de Novokuznetsk mobilizaria as primeiras equipes de resgate duas horas depois do desaparecimento daquele voo. As autoridades russas mobilizariam uma operação de busca e salvamento composta de 238 homens, 4 aviões e 3 helicópteros. Porém, o mau tempo (nevasca) e o local da queda, de difícil acesso, atrasariam o resgate dos corpos e destroços. As caixas pretas seriam encontradas e seriam fundamentais para a revelação da causa do acidente.

As autoridades russas suspeitaram inicialmente de atentado terrorista e/ou despressurização da cabine, pois nenhuma comunicação de anormalidade fora feita pela tripulação do voo 593 até à sua abrupta queda.

Investigações

Segundo dados de manutenção, o Airbus A-310 estava com sua manutenção em dia, e era pilotado por duas tripulações experientes. A análise dos dados das caixas pretas revelou a causa do acidente.

Durante aquela viagem, o comandante Yaroslav Kudrinsky levou seus filhos Yana e Eldar a bordo. Em um trecho do voo no qual o Airbus voava sob o comando do piloto automático, o comandante conduziu seus filhos até a cabine e os convidou a sentar em sua poltrona. Depois disso, ele os incentivou a movimentar o manche da aeronave. Yana simulou uma curva com a aeronave (previamente programada pelo comandante através do piloto automático), e, depois disso, Eldar, de 15 anos, realizou a mesma manobra. No entanto, Eldar exerceu uma força suficiente no manche para desconectar parcialmente o piloto automático. Sem perceber isso, a tripulação continou o voo sob o comando parcial do piloto automático, que havia tornado manual o controle dos ailerons. Assim, a aeronave se inclinou a 45 graus, de forma que sua asa direita afundou.

Com a queda repentina a uma grande velocidade, a força G fez com que os ocupantes da cabine ficassem presos aos seus assentos. Alarmes na cabine indicaram o desligamento do piloto automático e o risco iminente de perda de sustentação. No último instante, um dispositivo automático da aeronave conseguiu corrigir a posição e atitude da aeronave, o que permitiria a uma tripulação experiente corrigir a altitude e a rota da mesma.

O co-piloto, num esforço desesperado, conseguiu tirar a aeronave da queda. Mas ao realizar a manobra para fazê-la subir, fez com que a mesma perdesse sustentação e iniciasse um violento mergulho em parafuso. O comandante conseguiu retomar seu lugar e iniciou os procedimentos juntamente com o co-piloto para recuperar o controle da aeronave, mas ela estava voando abaixo do limite de segurança para aquela região e, com isso, colidiu com um morro de 600 metros.

Os investigadores descobriram que o filho do comandante exerceu uma força no manche suficiente para desligar parcialmente o piloto automático. As aeronaves russas anteriormente operadas pela Aeroflot possuíam alarmes sonoros para informar o desligamento total do piloto automático, mas não para informar o desligamento parcial do mesmo. A tripulação russa não foi instruída quanto à possibilidade de desligamento parcial do piloto automático, de forma que demoraria a entender o que estava ocorrendo com a aeronave.

A descoberta dos corpos dos filhos do comandante nos destroços da cabine confirmou as informações transcritas das caixas pretas. O acidente causou uma crise no alto escalão da Aeroflot, que, temendo o vazamento da história e seus efeitos negativos, tentou em vão ocultar a história. Quase um mês após o acidente, a imprensa russa obteve a informação de que o filho do comandante estava pilotando a aeronave.

Consequências

Após o acidente com o voo 593, a indústria da aviação comercial investiu em melhorias no treinamento de tripulações e a indústria aeronáutica introduziu alarmes para o caso de desligamento parcial do piloto automático.

A Aeroflot mudou o número do voo para Hong Kong em 2012, quando passou a ser chamado SU212.

Transcrição dos últimos minutos na cabine
O horário mostrado refere-se ao tempo marcado no gravador de dados do voo e não ao horário local ou GMT.

2258 Eldar (filho de Kudrinsky): Por que ele está virando?
2259 Kudrinsky (comandante): Está virando sozinho?
2260 Eldar: Sim...
2261 Kudrinsky: Eu não sei por que ele está virando.
2266 Eldar: Será que ele está saindo do curso?
2267 Piskarev (co-piloto): Estamos entrando em movimentação circular (holding pattern).
2268 Kudrinsky: Sério?
2269 Piskarev: Com certeza.
2270 Makarov: Rapazes...

O avião entra em um ângulo de inclinação de 45°. A força g aumenta fazendo com que Kudrinsky encontre dificuldades para voltar ao seu assento.

2272 Kudrinsky: Segura, segura o manche, segura.
2275 Makarov: A velocidade...
2276 Piskarev: O outro jeito!
2277 Kudrinsky: Do outro jeito, vire a esquerda.
2281 Piskarev: Esquerda!
2281 Kudrinsky: Esquerda... do outro jeito!
2282 Piskarev: Esquerda!
2284 Eldar: Estou virando para a esquerda...
2284 Piskarev: Para a direita!
2285 Kudrinsky: À direita
2288 Piskarev: Você não pode ver, ou o quê?

Neste momento os dois tripulantes ainda não haviam conseguido retornar aos seus assentos e tentavam em vão instruir Eldar de forma confusa e desesperada. Os alarmes de perda de altitude, desligamento total do piloto automático e de excesso de velocidade começaram a soar conjuntamente.

2291 Piskarev: Vire à direita. Vire à direita! Vire à direita!
2297 Kudrinsky: DIREITA!
2298 Piskarev: Esquerda! Lá está o chão!
2303 Kudrinsky: Eldar, sai daí... desce daí... desce daí Eldar.
2314 Piskarev: Manetes em idle!

O co-piloto consegue assumir a aeronave e tirá-la da posição de mergulho, porém, ainda atordoado, exagera ao puxar o manche. A aeronave então começa a subir quase que verticalmente com o nariz empinado.

Kudrinsky ainda encontrava dificuldades para voltar a sua poltrona. Desesperado, grita sem parar para o filho sair de seu assento.

2319 Kudrinsky: Eldar, saia! Saia, Eldar, saia... saia, Eldar, saia, saia... saia... [ofegante] saia! Eu disse para sair!
2334 Piskarev: Potência máxima! Potência máxima! Potência máxima!

Kudrinsky consegue retornar aos controles do avião.

2336 Kudrinsky: Está em potência máxima, entendi.
2337 Piskarev: Potência máxima!
2338 Kudrinsky: Entendi.
2340 Piskarev: Potência máxima.
2346 Kudrinsky: Eu dei-lhe potência máxima.
2348 Piskarev: Qual é a velocidade?
2354 Kudrinsky: [ofegante] Força total!
2365 Piskarev: A velocidade está muito alta.
2367 Kudrinsky: Alta, né?
2368 Piskarev: Sim, não é?
2369 Kudrinsky: Eu desliguei...
2371 Piskarev: Estamos saindo, estamos saindo! Direita! Para a direita! A velocidade está alta, reduza a potência.
2377 Kudrinsky: Feito.
2382 Piskarev: Devagar! Droga, de novo não...
2388 Kudrinsky: Não vire para a direita, a velocidade [ininteligível]
2392 Piskarev: [ininteligível]
2393 Kudrinsky: Nós vamos sair em um segundo. Tudo está bem. Delicadamente... [ininteligível] Delicadamente. Puxe delicadamente.
2400 [Som de impacto, fim da gravação]

Na cultura popular

O acidente com o Voo 593 da Aeroflot seria retratado na 3.ª temporada da série Mayday, do National Geographic Channel.

Ligações externas

Aeroflot 593
Aeroflot 593
Aeroflot 593
593
1994 na Rússia
Aeroflot 593

redpajama_set_name: RedPajamaWikipedia


" The rapper opened the show with a performance with Rihanna and rapped a medley of Drake & Migos song, but, as usual, he needed to show that he was still angry at the world as he was MIA when accepting his awards at the Nokia Movie. The painting was undoubtedly the response of Brown to all of the flak he's been receiving since the assault allegations arose due to Sunday night altercation with singer Frank Ocean, a battle first reported on by TMZ, outside an H. A. recording studio. 2 men in addition entourages reportedly had words over a parking space, words that degenerated into some kind of scuffle. Brand new York Post reported that Ocean is contemplating pressing charges against Brown for assault. More information about Cheapest App To Buy Drake Migos Concert Tickets Vivint Smart Home Arena.
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Babylon will be destroyed and never rise again—The scattered people of Israel will be brought again into the lands of their inheritance.
1 The aword that the Lord spake against Babylon and against the land of the Chaldeans by Jeremiah the prophet.
2 Declare ye among the nations, and publish, and set up a standard; publish, and conceal not: say, Babylon is taken, aBel is confounded, Merodach is broken in pieces; her idols are confounded, her images are broken in pieces.
3 For out of the anorth there cometh up a nation against her, which shall make her land desolate, and none shall bdwell therein: they shall remove, they shall depart, both man and beast.
4 ¶ In those days, and in that time, saith the Lord, the children of Israel shall acome, they and the children of Judah btogether, going and cweeping: they shall go, and seek the Lord their God.
5 They shall ask the way to Zion with their faces thitherward, saying, Come, and let us join ourselves to the Lord in a aperpetual bcovenant that shall not be forgotten.
6 My people hath been lost sheep: their ashepherds have caused them to go astray, they have turned them away on the mountains: they have gone from mountain to hill, they have forgotten their restingplace.
7 All that found them have devoured them: and their adversaries said, We aoffend not, because they have sinned against the Lord, the habitation of justice, even the Lord, the hope of their fathers.
8 aRemove out of the midst of Babylon, and go forth out of the land of the bChaldeans, and be as the he goats before the flocks.
9 ¶ For, lo, I will raise and cause to come up against Babylon an assembly of great nations from the anorth country: and they shall set themselves in array against her; from thence she shall be taken: their barrows shall be as of a mighty expert man; none shall return cin vain.
12 Your mother shall be sore confounded; she that bare you shall be ashamed: behold, the ahindermost of the nations shall be a wilderness, a dry land, and a desert.
15 Shout against her round about: she hath agiven her hand: her foundations are fallen, her walls are thrown down: for it is the vengeance of the Lord: take vengeance upon her; as she hath done, do unto her.
16 Cut off the sower from Babylon, and him that handleth the sickle in the time of harvest: for fear of the oppressing sword they shall turn every one to his apeople, and they shall flee every one to his own bland.
17 ¶ Israel is a scattered sheep; the lions have driven him away: first the king of Assyria hath devoured him; and last this Nebuchadrezzar king of Babylon hath abroken his bones.
19 And I will abring Israel again to his habitation, and he shall feed on Carmel and Bashan, and his soul shall be satisfied upon mount Ephraim and Gilead.
20 In those days, and in that time, saith the Lord, the iniquity of Israel shall be sought for, and there shall be none; and the sins of Judah, and they shall not be found: for I will apardon them whom I reserve.
21 ¶ Go up against the land of Merathaim, even against it, and against the inhabitants of Pekod: waste and utterly destroy after them, saith the Lord, and do according to all that I have commanded thee.
27 Slay all her bullocks; let them go down to the slaughter: woe unto them! for their day is come, the time of their avisitation.
34 Their Redeemer is strong; the Lord of hosts is his name: he shall throughly aplead their cause, that he may give rest to the land, and disquiet the inhabitants of Babylon.
35 ¶ A sword is upon the Chaldeans, saith the Lord, and upon the inhabitants of Babylon, and upon her princes, and upon her wise men.
37 A sword is upon their horses, and upon their chariots, and upon all the amingled people that are in the midst of her; and they shall become as women: a sword is upon her btreasures; and they shall be robbed.
38 A adrought is upon her waters; and they shall be bdried up: for it is the land of graven images, and they are mad upon their idols.
39 Therefore the wild beasts of the desert with the wild beasts of the islands shall dwell there, and the aowls shall dwell therein: and it shall be no more inhabited for ever; neither shall it be dwelt in from generation to generation.
40 As God overthrew aSodom and Gomorrah and the neighbour cities thereof, saith the Lord; so shall no man abide there, neither shall any son of man dwell therein.
41 Behold, a people shall come from the anorth, and a great nation, and many kings shall be raised up from the bcoasts of the earth.
42 They shall hold the bow and the lance: they are acruel, and will not shew mercy: their voice shall roar like the sea, and they shall ride upon horses, every one put in array, like a man to the battle, against thee, O daughter of Babylon.
44 Behold, he shall come up like a lion from the swelling of Jordan unto the habitation of the strong: but I will make them suddenly run away from her: and who is a chosen man, that I may appoint over her? for who is like me? and who will appoint me the time? and who is that ashepherd that will stand before me?
46 At the noise of the taking of Babylon the earth is amoved, and the cry is heard among the nations.


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Remember the story about King Midas and everything he touched turn to gold? Well, I have been using my own Midas touch to turn the glam up on these framed prints in the dining room. When I recently shared the new look of the dining room I told y'all there was another change to something in there.
For those of you who remember these you are probably saying weren't these gold in the first place?
Why, yes they were as you can see in this fall photo I pulled out. Thing is, it was a cheap looking gold because those frames are cheap ones from Hobby Lobby and I never really liked the factory finish on them.
Then I had the bright idea of making them darker with black guilder's paste to give them an antique look, but after painting the chairs lighter they just weren't working for me anymore.
This time I used my guilder's paste in gold and just brushed it on.
Now they look more like aged brass that is back in style.
Okay, I know you are tired of seeing the dining room. That is all the changes.....for now.
Have a fabulous Easter weekend and be sure and return tomorrow for another fabulous favorite room.
The gallery wall of prints are vintage floral pages I purchased from ebay and framed myself.
I never grow tired of seeing that chandelier!
The frames look very nice redone like that. I also really like the way the chairs turned out at your table. The yellow and white in the room really gives it that country french look.
Morning Kimmie! I love your dining room and your frames look wonderful. Your arrangement on your table is pretty too. Hope you're doing well.
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Your room looks great, as do the frames! You mentioned they were from Hobby Lobby. Did you frame them yourself?
So pretty, I never tire of seeing your pretty dining room...so much eye candy! Happy Easter Kim!
the table.. just call me!
They look pretty and brighter.
Third time a winner - I like them very much with the new/old finish!
Isn't it amazing what a difference that makes-just beautiful.
I just laughed out loud over the ....why yes they were gold. We all have decorating ADD or "so I changed my mind again" feelings.
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I'm wondering the same thing Jane is wondering. Did you frame them yourself? If so, I would love to see a tutorial. I have very similar floral prints I found in a book at an antique store that I had professionally framed. If I wanted to paint the frames a different color, I would probably have to take the backings off to get the prints, glass, etc. out.
we are never sick of seeing this gorgeous room!
They look beautiful! I've never used Guilder's Paste...will have to investigate that.
I love looking at your dining room. That Guilder's Paste looks great...I want to try it.
Guilder's paste to the rescue! I have to get some of that stuff!
They looks great Kim. I never noticed your painted ceiling before! That looks great too.
I don't even know what Guilder's Paste is...but, I like the look. It seems as if I just painted over all my gold frames, does this mean it is time to bring them all back to gold? Oh my.
Don't ya' just love Guilder's Paste? Your frames look fabulous with a new gold finish! Happy Easter!
I love your dining room especially with the bench and gorgeous chandelier. Big impact on a little change to the artwork.
Love how they turned out Kim! I have a couple I'm going to try dark wax on. Your dining room looks fab...I seem to be making all my changes in mine these days too!
Your dining room is lovely, Kim. I had a set of framed prints that I ended up putting in a yard sale because the gold was cheap looking and the backs were sealed with dust paper. This would have been a great solution.
I love the new finish...such a beautiful dining room too!
Yes the gold looks perfect with your color palette! And no Kim I never get tired of seeing photos of your beautiful dining room! Happy Easter!
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I love all that pretty yellow in your dining room. So bright and cheerful!
They look so good with your ceiling color!
:-) I never tire of seeing your dining room Kim.
I'd say they are pretty perfect now!
Well I don't know about the midas touch on the frames, but you do have the midas touch in decorating!
You did it again Kim, these are perfection and really are stunning. I like that they look like aged brass. Happy Easter!
P.S. I really enjoyed your interview with Anita!
I love the aged brass look. Your dining room is beautiful!


text:
Sailors, Coconuts, and a Monkey
By Jennifer Newell / Computer Programming Projects & Puzzles for Kids / February 2020 Issue
Phillip Capper on Flickr
Can you figure out how to divide up coconuts between a group of sailors and a monkey? This puzzle mixes math and coding. Plus you can go online to try the code yourself.
This puzzle mixes math and coding. Plus you can go online to try the code yourself.
In his book The Colossal Book of Mathematics: Classic Puzzles, Paradoxes, and Problems, Martin Gardner simplified a classic question about monkeys and coconuts. His simplified version goes as follows:
"Three sailors come upon a pile of coconuts. The first sailor takes half of them plus half a coconut. The second sailor takes half of what is left, plus half a coconut. The third sailor also takes half of what remains, plus half a coconut. Left over is exactly one coconut, which they toss to the monkey. How many coconuts were in the original pile? If you arm yourself with 20 matches, you will have ample material for a trial-and-error solution."
To get a feel for the problem, let's guess that the sailors collect 9 coconuts.
That means the first sailor takes half of 9 (4.5) plus .5 more for a total of 5 coconuts. How many coconuts are left for the second sailor?
Well, that would be the total minus what Sailor 1 took, 9 – 5 = 4.
The second sailor takes half of the 4 (2) plus ½ more, making 2.5. That means he leaves 4 – 2.5, or 1.5 coconuts for the 3rd sailor.
Finally, Sailor 3 takes half of 1.5 (.75) plus 0.5 coconuts, for a total of 1.25.
If Sailor 3 started with 1.5 coconuts and took 1.25 coconuts, there is ¼ of a coconut left. But that is problematic since the question says that at this point we should have exactly one whole coconut remaining to toss to the monkey.
We could make a second guess, and then possibly and third and so on until we end up with 1 coconut for the monkey. However, we are likely to make mistakes along the way, or just get frustrated and quit.
Mr. Gardner recommends arming oneself with 20 matches, implying the answer is no more than 20, but how about we arm ourselves with a little code as well?
Since we understand the process of dividing up the coconuts for each sailor, we can write a program to do the calculations for us. We will still need to make a guess, but the computer can do the calculations and tell us if our next guess should be higher or lower. We'll give this a try in Python.
This program gets us the answer, but leave plenty of room for improvement. If you have a bit of programming experience, you can challenge yourself to rewrite them with fewer lines of code, or by defining functions.
The answer might be much more than 20, so you'll probably want a program that makes all the guesses for you.
Here's the process in pseudo-code:
Guess a number
Divide it by 2 and add ½
Subtract the answer from our original guess
Repeat the process two more times
And here's the pseudo-code written in Python 3 code to try at the repl.it website:
#our first guess is 17, you can replace 17 with your own guess
total = float(17)
#we want to figure out how many coconuts all 3 sailors get, so we need to loop through the algorithm 3 times. You can replace the numbers in range(1,4) with any two numbers that are 3 apart.
sailorTakes = total/2 + .5
print("Sailor",i, "takes", sailorTakes)
remaining = total - sailorTakes
total = remaining
print("There are", total, "left")
print("-------------------")
if(total == 1):
print("You got it!")
elif(total > 1):
print("Guess a smaller number")
print("Guess a bigger number")
Project Code in Repl.it
https://repl.it/FyJE/7
The Colossal Book of Mathematics: Classic Puzzles, Paradoxes, and Problems
http://books.wwnorton.com/books/978-0-393-02023-6/
http://www.indiebound.org/book/9780393020236
http://www.alibris.com/The-Colossal-Book-of-Mathematics-Classic-Puzzles-Paradoxes-and-Problems-Martin-Gardner/book/28766065
Martin Gardner's Puzzle Books
http://martin-gardner.org/PuzzleBooks.html
Jennifer Newell
Jennifer is a math teacher by training, with an interest in computer science. While working on a computational thinking project at Google, she dived a bit deeper into CS education. Jennifer now teaches computer science to both high school and elementary school students, in addition to mathematics.
Also In The February 2020 Issue
Can you figure out how to divide up coconuts between a group of sailors and a monkey? This puzzle mixes math and coding. Plus you can go online to try the code yourself!
Python Mad Libs
Recreate the classic game in this simple Python tutorial. What whimsical stories can you write?
If you like ships, then you'll love this easy-to-use website that keeps track of seafaring vessels around the world. Bonus: it helps prevent maritime collisions!
Ready for some good old-fashioned winter fun? In this article, build a digital snowman with Sketchup.
Programming Memes
A fun, silly way to share your coding trials and triumphs with friends — because everything is better with kittens!
How to Pick a Programming Language
Should you learn Python, Scratch, Java, Assembly? If you're feeling overwhelmed by too many options, this article is here to help.
Computers are good at following instructions, but not at reading your mind.
— Donald Knuth
Computational Thinking in the Wild
Illustrating computational concepts like decomposition and algorithms with simple, hands-on, and occasionally messy activities.
Tech in Real Life (IRL)
Smart Street Lights
How do street lights know when to turn on? And what's in store for the street lights of the future?
Video Game Light Guns
In the old days, before video game systems had cameras and sensors, programmers had to get creative.
The First Computors
Six women were hired to use their math skills to program the ENIAC computer. They called themselves The First Programmers Club.
What is a Firewall?
Learn about the key software that keeps your computer safe from viruses.
Software Version Conventions
Programs are constantly being patched and improved. How do we keep track of all this new code?
Binary What?
Dive into the nitty-gritty details of binary numbers: how they work, why they're used, and where they come from.
Binary Riddles
Binary might be the language of the computer, but we humans can use it to decode secret messages.
Programming 3D Art in Shadertoy
An easy way to code your own 3D graphics online. Dive into the world of pixels, triangles, textures, and colours!
Finite Automata
Learn about the smallest, simplest computers and where they're still used today.
Squeak!
Why Smalltalk is such a unique language, and how it evolved into modern variants like Scratch, Squeak, and Pharo.
February 2020 News Wire
Interesting stories about science and technology for February 2020.
February 2020 Learn More Links
Links from the bottom of all the February 2020 articles, collected in one place for you to print, share, or bookmark.

redpajama_set_name: RedPajamaCommonCrawl


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Association for Specialist Fire Protection
Fire & Safety: An Industry Focus: Association for Specialist Fire Protection
The Association for Specialist Fire Protection (ASFP) was formed in 1975 in recognition of a need to bring together passive fire protection manufacturers, contractors and testing/certification bodies to encourage, develop and give guidance on essential standards in passive fire protection.
The Association reflects a diversity of expertise in the fields of fire stopping, fire resisting ducting, fire dampers, fire resisting partitions and all elements used for compartmentation.
For forty years, the ASFP has either taken the lead or maintained a significant input into developing the vast majority of guidance and standards that exist today across the whole spectrum of the passive fire protection sector.
In recent years, the ASFP has progressively broadened its membership and remit to reflect and respond to the significant changes and challenges within the fire sector and the built environment in terms of technical innovation, regulatory direction, the changing political dimension, evolving commercial forces and geographic expansion of the industry.
In September 2018, the Association for Specialist Fire Protection (ASFP) was pleased to announce that the Royal Institute of British Architects (RIBA) has launched a consultation on a new RIBA Plan of Work for Fire Safety.
The document represents the culmination of work which was initiated in 2016 when the ASFP convened a panel of stakeholders from across the built environment to investigate how fire protection could be improved throughout the construction cycle. All identified a number of issues with the construction process, including: fragmentation within the construction design and build process, multiple sub-contracting and inadequate inspection of works during construction and on completion.
Working with AHMM Architects, the stakeholder group recognised that developing a Plan of Work for Fire Safety, which complemented the existing RIBA work plan methodology, would provide a recognisable route for improvement. The work took on greater urgency following the devastating fire at Grenfell Tower in June 2017 and the ASFP commends RIBA for taking the initiative forward to develop this vital resource for design and construction teams and building owners.
The new RIBA Plan of Work ensures there is a detailed specification for fire protection at the design stage and a schedule for fire throughout the construction process. The Plan of Works includes sign offs as construction progresses, with all information reaching the end-user to support adequate fire risk management.
The new document also reflects the recommendations of the Hackitt review, which called for a greater focus on the roles and responsibilities and a 'Golden thread' throughout a building's lifecycle. The review also recommended the introduction of mandatory sign off procedures at the key Gateway Points of: Planning Permission, Permission to Build and Permission to Occupy.
ASFP CEO Niall Rowan stated:
"The ASFP welcomes the launch of this important consultation which represents a vital step forward in improving the safety of our built environment.
"We have long called for fire to be considered much earlier in the construction process and this new document clearly sets out the requirements and responsibilities at each stage of the process, from original design and throughout the life of the building, including changes and refurbishments later in the building's life.
"The document represents the successful conclusion of many months of work involving a wide range of stakeholders from across the construction industry and as such we hope will gain strong support and recognition."
Fire Protection Association
The Fire Protection Association (FPA) is the UK's national fire safety organisation. Since 1946 the association has attained an unrivalled reputation for quality of work and expertise in all aspects of fire including research, consultancy, training, membership, publications, risk surveying and auditing. The FPA's products and services are designed to assist fire, security and safety professionals achieve and maintain the very highest standards of fire safety management.
The Fire Protection Association's Fire Sector Summit is an annual event, held in October, which over the past eight years has become an established leading industry forum for key decision makers and influencers in the fire sector. The Summit aims to encourage discussion and debate on the sector's most recent developments and themes and act as a catalyst for change within the world of fire safety.
The overriding message from the 2018 Fire Summit was that post-Grenfell and pre-Brexit, the heat is still on for dramatic change and vigilance in the fire protection industry.
The Summit brought together the best in the business of the British fire industry, with over 150 delegates joining a panel of experts in a packed lecture theatre at the Institute of Civil Engineers. A special session was run on Grenfell by Fire Protection Association's (FPA) Managing Director Jonathan O'Neill, and his colleagues, Principal Consultant Howard Passey and Technical Director Dr Jim Glockling. Jonathan O'Neill discussed the background of the FPA's attempts in the lead up to the fire to change government policy, with 14 June 2017 turning the 'world upside down'. With no review of building regulations in 14 years, he shared the FPA and insurers' own document that was created as a response.
He also addressed the work that the FPA had done to lobby government, such as the Safe Futures campaign of 2013, before discussing modern methods of construction (MMC) and their risks, specifically in terms of the use of combustible materials in increasing quantities within the structure, insulation, and cladding of buildings.
The Brexit session was presented with an overwhelming air of uncertainty. Anthony Burd, Head of the Built Environment at the British Standards Institute started by saying that "for us, it's business as usual" as not much will be changing with standards, but as he believes firmly in continuity, if the Brexit negotiations result in a no deal, guidance on trade would be affected.
Paul Pope, Director of the Fire Industry Association, believes that the fire industry effects are a risk to business, because "potential recertification could happen" and this could affect orders dramatically, as 80% of global trade needs product certification. He commented that we "really don't know what it means for us" so we must prepare for the worst. Howard Passey, Principal Consultant at the FPA stated that at this stage "nobody knows!" what the implications are, so it's important that as laws could be changed "at a whim" the fire industry must undertake "effective surveillance" on government changes. He urged the need to be vigilant.
Fire Safety And The Construction Industry
The first research to investigate what has changed in construction practice since the Grenfell Tower fire reveals a wide range of improvements being implemented by the industry itself, but a growing frustration with the slow response from Government – despite a promise by the Housing Minister to ban combustible cladding in the future on high risk buildings.
Construction industry professionals report that since the fire in June 2016 they have most often seen changes in the products used for cladding, insulation and fire doors, as well as more demands for new fire testing of products.
They also report changes to the way procurement policies, tenders and contract terms deal with fire safety issues and responsibilities. The research was conducted for UK Construction Week (UKCW) which opens today. UKCW received detailed responses from respondents across all parts of the industry.
While many of the respondents are monitoring Government advice and waiting for the outcome of a current review of Building Regulations, they are critical of the time being taken to clarify new requirements since the fire and the subsequent publication of the Hackitt Review in May 2018.
Comments from research respondents included:
"I just wish that action could happen more quickly", and "Things are changing, but way too slowly." One person said: "The Government will take a decade to produce yet another set of incomplete regulations together, and will probably produce another White Paper. They need to set a clock on this."
In the meantime, the construction industry is getting on with things itself.
Among a wide range of changes, respondents to the research are most likely themselves to have implemented reviews of all their current project designs and specifications, to have commissioned additional fire risk assessments on projects, and to have increased training on fire safety.
Indeed, when asked about their top three preferred changes to transform fire safety across all buildings (not just high-rise blocks or other high-risk buildings), the industry is not simply counting on new regulations. That comes sixth on the list of their priorities.
The first choice is greater involvement of an architect, Clerk of Works, fire engineer, the fire and rescue service itself or other professional adviser who would do a full fire risk assessment and ensure better design and specification. Many called for the end of contractor-led 'Design and Build' type contracts.
A close second is a change in the choice and attention given to materials being specified and used on all buildings, including many supporting the ban on combustible materials in exposed areas of a building, in particular cladding or insulation.
Third choice is the installation and regular maintenance of sprinklers and other active fire detection and suppression equipment into all buildings. The UKCW research shows that confidence among construction industry professionals that, post-Grenfell, the UK's approach to fire safety in all buildings will now change for the better, currently stands at 6 out of 10.
Contractors, specialist sub-contractors and building products suppliers are marginally more confident than other groups (with an average confidence score of 7 out of 10). Nathan Garnett, event director at UK Construction Week, says:
"Our research shows that the industry has taken to heart every opportunity to change its practice and is already well along a process that will change the way all buildings are procured, design, built and maintained.
"This is an issue that will be discussed widely at next week's event, and is likely to remain the highest agenda item for years to come. While confidence is quite good at this time, we must do all we can to maintain the positive attitude and momentum behind these changes."
Geoff Wilkinson, managing director of Wilkinson Construction Consultants, a fire safety and building standards expert and one of the speakers at this year's UKCW seminar on quality in construction post-Grenfell, says:
"It is very encouraging to see the industry getting on with it, despite the hiatus from Government. But what's needed is an industry-wide coordinated response.
"The ban on combustible materials is long overdue. We need to be told why it has taken over a year to get to this point when a very simple changing of regulatory guidance could have achieved the same thing in days."
The UKCW seminar on this topic took place on 10 October 2018, with other speakers at this event including Jonathan O'Neill, managing director at the Fire Protection Association, Peter Capelhorn, deputy chief executive and policy director at the Construction Products Association and Claire Curtis-Thomas, chief executive of the BBA.
Intersec 2019
The world's leading trade fair for security, safety, and fire protection, is taking place from 20-22 January 2019 at the Dubai International Convention and Exhibition Centre.
Intersec 2019 is organised by Messe Frankfurt Middle East, and returns with key government supporters such as Dubai Police, Dubai Civil Defence, Dubai Police Academy, Dubai Municipality, and the Security Industry Regulatory Agency (SIRA).
The annual showpiece includes a revamped conference line-up, including a three-day Intersec Future Security Summit raising key issues on Artificial Intelligence, security Integration, emergency preparedness and response, data protection, IoT and much more.
Fire & Rescue is the second largest of seven show sections at the annual three-day event, where more than 1,300 exhibitors from 59 countries are set to take part in the show's 21st edition early next year.
The Fire & Rescue section will include the biggest names in the global fire and life safety business such as UAE-based powerhouses NAFFCO and Concorde Corodex Group, Honeywell from the USA, Japanese-headquartered Hochiki, Drager from Germany, and Turkish fire truck manufacturer, Volkan.
Eaton Corporation is another headline exhibitor in the Fire & Rescue section, and is one of many companies at Intersec 2019 positive about the current and future fire safety trends in the regional market.
Frank Ackland, Eaton's Middle East Managing Director said the regulations set out by the UAE Civil Defence for example, offer a much higher standard of regulation than has ever been seen before: "Eaton provides emergency lighting and fire detection systems for buildings and we've noted an increase in the levels of regulation that are being adhered to – not only to the set standard but also above in many cases.
"All those involved in the construction process are placing greater importance of meeting, and exceeding, the standards set out. That doesn't mean there isn't more work to be done, and this is where we see a significant investment in retrofitting also taking place in the UAE, in order to make older buildings safer and in line with current regulations."
Intersec 2019 is held under the patronage of His Highness Sheikh Mansoor bin Mohammed bin Rashid Al Maktoum, and supported by the Dubai Police, Dubai Police Academy, Dubai Civil Defence, SIRA, and the Dubai Municipality. More details about the exhibition is available at: www.intersecexpo.com.
Ten Kites Partners with IndiCater to Simplify Multi-Channel Deployment of Allergen-Compliant Recipes and Consumer-Facing Menus
Now Is The Time To… Reflect, Engage and Set Goals


Un article sur le jugement majoritaire, qui oblige à donner un avis sur chaque candidat·e, plutôt que d'en sélectionner un·e. L'intérêt, c'est de juger des candidat·es en tant que tel·les, sur leur programme, et pas seulement parce qu'ils ou elles ont des chances d'accéder au second tour, et d'aller chercher dans les seconds choix des électeurs et électrices de quoi trouver un terrain de concertation. Je ne comprends pas pourquoi ça s'appelle majoritaire, c'est justement assez pluraliste pour l'élection d'une seule personne !
Research is needed on how groups make choices in real situations, write Guruprasad Madhavan, Charles Phelps and Rino Rappuoli.
The massive East Antarctic Ice Sheet looks stable from above — but it's a dangerously different story below.
Like ivy plants that send runners out searching for something to cling to, the brain's neurons send out shoots that connect with other neurons throughout the organ. A new digital reconstruction method shows three neurons that branch extensively throughout the brain, including one that wraps around its entire outer layer. The finding may help to explain how the brain creates consciousness.
Les fosses marines sont parmi les lieux les plus contaminés au monde par les polluants organiques persistants (POPs), dont les PCB, révèle une étude publiée lundi 13 février dans Nature Ecology & Evolution.
We were increasingly in awe that a remote, almost unknown, wilderness such as this could still be found on Earth today.
An 'artificial satellite' at the correct distance from the earth would make one revolution every 24 hours; i.e., it would remain stationary above the same spot and would be within optical range of nearly half the earth's surface. Three repeater stations, 120 degrees apart in the correct orbit, could give television and microwave coverage to the entire planet.
The first commercial communications satellite, Telstar I, was built by Bell Telephone Laboratories and launched in 1962. The first to be geostationary, the Hughes Aircraft Company's Intelsat I ('Early Bird'), went up in 1965. Both launched on conventional rockets, and operated with transistors and without human maintenance. The two US engineers chiefly responsible — John Pierce for Telstar and Harold Rosen for Intelsat — saw Clarke as the father of satellite communications. Richard Colino, director-general of Intelsat (the International Telecommunications Satellite Organization) agreed in his foreword to a collection of Clarke's technical writings, Ascent to Orbit (1984). Clarke preferred "godfather", noting with uncharacteristic modesty in the book that he had received "rather more of the credit, I suspect, than I really deserve". In old age, however, he told me that his comsat article was "the most important thing I ever wrote".
Conclusion : publiez vos idées afin qu'elles fassent des enfants.
Scientists who do research funded by the Bill & Melinda Gates Foundation are not — for the moment — allowed to publish papers about that work in journals that include Nature, Science, the New England Journal of Medicine (NEJM) and the Proceedings of the National Academy of Sciences (PNAS).
Reporterre sur France Inter : les batteries ont l'avenir devant elle, mais sera-t-il écologique ?
young biomedical scientists who have started companies instead of taking the conventional academic path and pursuing postdoctoral studies after their PhDs. Among the factors driving this change are an infusion of money into early-stage biotech investing, the emergence of biotech incubators and the scarcity of academic jobs in science.
But an analysis of HIV using decades-old blood serum samples exonerates the French Canadian [Gaétan Dugas], who died in 1984. The paper, published on 26 October in Nature, shows that the virus had been circulating in North America since at least 1970, and that the disease arrived on the continent through the Caribbean from Africa.
Richard McKay, a historian at the University of Cambridge, UK, and study co-author, says that scientists have always questioned the idea of a single #Patient_Zero, because some evidence suggested that the virus entered North America several times.


Samurai Slasher is a comic by Mike Garley based on an imaginary 80 horrors film. You know the genre, though, college students turn up at the lake for some skinny dipping and smoking weed only to encounter an immortal samurai determined to slaughter them all.
Late Fees is very different. This comic, limited to a 666 copy print run, mixes slice of life with that 80s horror. Slasher of life?
This comic has a completely different perspective. It is told from in the first person by a kid who's dad lets him watch the Samurai Slasher film on the strict promise not to tell mum. A healthy father-son relationship?
As it turns out the father has some issues of his own and the lad grows up using the image of the slasher as his coping mechanism. Drama and troubles become metaphorical battles where the Samurai Slasher isn't just the good guy, he's the armour the kid wears, and battles against all sorts of demons.
It's an interesting approach to storytelling. It's worth saying that you don't need to have read any of the original Samurai Slasher series to enjoy Late Fees. I hadn't. I went back to read some after enjoying Late Fees and it's a turnabout to encounter the Samurai back in the role of atypical 80 horror movie baddie.
The artist on this project is Lukasz Kowalczuk. That's a name I keep on seeing peppered around those few comic forums I visit. The illustrations in Late Fees certainly live up to any expectations. There's a bold mix of dark and light in Late Fees. Monsters are often surreal colour forms that feel appropriate as representations of dramas and hardships. The samurai is a blend of shadow and blood.
Whirls of colour might threaten the careful balance of life vs fiction in Late Fees but Kowalczuk nails it and his mixing helps solidify the story.
I recommend getting hold of one of the limited editions of Late Fees. If it's not too late. Got one already? Keep it safe.
My PDF copy of Late Fees was provided for review.


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Snow Storm Causes Post-Thanksgiving Flight Delays and Cancellations Across Midwest
BYErin Corbett
November 25, 2018, 5:41 PM UTC
Thanksgiving travelers check in for their flights at O'Hare Airport on November 21, 2017 in Chicago, Illinois.(Photo by Scott Olson/Getty Images)
Scott Olson—Getty Images
Travelers going in and out of some Midwestern cities this Sunday are experiencing flight delays and cancellations on one of the busiest travel days of the year, with 15 states under a weather alert due to winter storm and blizzard warnings, ABC News reported.
Major cities including Kansas City, Mo., and Chicago are expecting heavy snow on Sunday. Kansas City in particular is under a blizzard warning, and could see anywhere from 4 to 9 inches of snow with 50 mph winds. Chicago, on the other hand, will see all-day rain turn to snow in the evening, with an expected 3 to 6 inches of snow on Sunday along with heavy winds.
As of Sunday morning, Chicago's O'Hare International Airport, a major travel hub, had reported 189 flight cancellations and Midway International Airport had reported an additional 19 canceled flights, according to WGN. Overall, nationwide, USA Today reported 500 canceled flights total, and another 700 delayed as of 11:50 am ET Sunday. Most cancellations came from cities across the Midwest.
The blizzard warning was issued by the National Weather Service for parts of Nebraska, Kansas, Missouri, and Iowa, according to the Associated Press. The heavy snow and strong winds across the Midwest are expected to cause whiteout conditions, which can affect visibility, causing dangerous travel.
According to AAA, more than 54 million Americans traveled over the Thanksgiving holiday this year, ABC 7 Chicago reported. In Illinois alone, 2.5 million people are driving, with hundreds of thousands also flying.
Air travelers should call their airlines before heading to the airport on Sunday for information about flight cancellations. Some airlines will also waive fees for flight changes.


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Home » Posts Tagged "TRADING"
Alphabet Tops Apple in Total Value
By Michael Liedtke AP Technology Writer - Feb 2, 2016
San Francisco — Alphabet, Google's new parent company, topped Apple as the world's most valuable business in after-hours trading Monday after reporting surging earnings. Alphabet Inc. earned $4.9 billion in net income on revenue of $21.3 billion in the fourth quarter. If not for employee stock expenses and certain other items, Google said it would have earned $8.67 per share. That figure easily topped the average estimate of $8.10 per...
SEC Report Sheds Light on Stock Market's August 'Flash Crash'
By Jonnelle Marte The Washington Post - Jan 3, 2016
Washington — When fears of a slowdown in China sent U.S. stocks plummeting in late August, some of the market mechanisms meant to protect investors during times of volatility may have triggered even greater losses among exchange-traded funds, market regulators said in a report released last week. Some investors were surprised during the early minutes of stock trading on Aug. 24 when they noticed that many ETFs became worth much less...
High Court Won't Take Overturned Insider Trader Conviction
By Sam Hananel Associated Press - Oct 6, 2015
Washington — The Supreme Court said Monday it won't hear the Obama administration's appeal of a lower court ruling that made it tougher to prosecute people for trading on leaked inside information. The justices let stand a decision by the federal appeals court in New York last year that threw out insider trading convictions of two high-profile hedge fund managers. The 2nd U.S. Circuit Court of Appeals overturned the convictions of...
Gold Drops to 1-Month Low
By Bloomberg News - Sep 13, 2015
Gold fell to a one-month low and trading volume declined as investors held off on making big moves before Federal Reserve policymakers meet this week. Gold is headed for a third straight annual loss as steady growth for U.S. jobs and the economy strengthened the dollar and bolstered the case for the Fed to raise interest rates for the first time since 2006. Futures trading was about 22 percent below the 100-day average on Friday, data...
Traders Recall 'Rush' and 'Roar' as Famed Futures Pits Set to Close
By Bernard Condon and Don Babwin Associated Press - Jul 6, 2015
New York — Pete Meegan had every intention of going back to college, but then he got a summer job in the Chicago trading pits and fell in love with the "roar" of the floor, the excitement of "4,000 people yelling, 'Buy! Buy! Buy!' " and decided no more classroom for him. That roar will soon go silent. Today, most futures pits in Chicago and New York, where frenzied buying and selling once helped set prices on cattle and corn,...


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Q: authenticate angularJs app using wordpress site users i've a desktop site based on wordpress.
Mobile version is on a subdomain and is developed using angularJs (ionic).
I'm trying to figure out what the best solution to authenticate mobile version users using wordpress wp_users credentials.
Thanks in advance for any advice.

A: 1 - Basic Auth: The easiest, This one is not recommended for production since your users will be sending their credentials with each request, only use it over https.
2 - OAuth: This one is secured but might not be interesting because users will be redirected to WP to login then redirected back after login success, here is a decent tutorial for it.
3 - JWT Auth: This one is interesting because it only sends user credentials once, when login succeed you will get a jwt token which will be used instead of user's password in each request.
For your app purpose I recommend implementing your own authentication method, make a plugin for that, it should generate a secret token and save it in user session, it should also block any request that doesn't include that secret token.

redpajama_set_name: RedPajamaStackExchange


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Home > Banking & Finance
MAS and Americas bank supervisors' body to bolster fintech ties
Fri, Jun 09, 2017 - 11:26 AM
Claire Huanghuangjy@sph.com.sg
The Monetary Authority of Singapore (MAS) and the Association of Supervisors of Banks of the Americas (ASBA) have inked a memorandum of understanding (MOU) to bolster fintech (financial technology) ties between Singapore and the Americas.
PHOTO: ST FILE
The agreement provides a framework for fintech cooperation between Singapore and ASBA member countries, the two parties said on Friday.
Under the framework, both parties can explore potential joint innovation projects on technologies such as blockchain and big data.
MAS and ASBA will also facilitate talks on issues of mutual interest, such as emerging fintech trends and issues on innovative financial services.
Sopnendu Mohanty, chief fintech officer, MAS, said: "Fintech is fundamentally about ideas and enterprise flowing between cities. It requires bringing together a range of stakeholders. This MOU embodies MAS' and ASBA's resolve in accelerating the growth of fintech in the respective regions, through increased collaboration and exchanges between our respective fintech ecosystems."
SEE ALSO: Refrain from leveraging HK unrest: S'pore wealth managers told
Rudy Araujo, secretary-general, ASBA, noted that by uniting efforts with the MAS, ASBA expects to support the development of a regulatory and supervisory framework that "while supporting financial stability, nurtures innovation, and promotes market transparency and proper conduct".
Singapore fintech
Singapore financial institutions
Association of Supervisors of Banks of the Americas


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The 'Nifty Fifty' Have Never Been Useful Anyway
by Andrew Lappin
Fifty of the nation's leading security minds, all of whom have had "situation room" exposure at one time or another, have signed a public statement opposing Donald Trump's presidential bid on the grounds that he "lacks the temperament to be president." Branding themselves as "centrists," the group includes former CIA and National Security Agency Director Michael Hayden, former Director of National Intelligence and Deputy Secretary of State John Negroponte, and Eric Edelman, who was former vice president Dick Cheney's national security adviser. It also includes two Homeland Security secretaries under Bush, Tom Ridge and Michael Chertoff, and Robert Zoellick, a former World Bank president, U.S. trade representative, and deputy secretary of state.
The statement obliquely questions Hillary Clinton's fitness for office, couched in a way that discreetly provides her with a safe zone by creating a "junior varsity" category of Hillary's "recklessness."
It's not the oversized double standard that stands out as much as the fact that not a single one of these esteemed judges of character has ever expended an ounce of energy to formulate a strategy to deal with radical Islam. Despite their previous positions of influence and power, our safe zone grantors have chosen instead to perpetuate the misguided policy of uncoupling jihadist violence from its 1,400-year-old Islamic roots, turning a blind eye to the burgeoning institutional and cultural infrastructure in our midst.
Say what you will about Donald Trump, but he has done more than any other public figure to put this glaring incongruity front and center. The more we learn about Khizr Khan (the Gold Star dad) and his professional involvement with Sharia law and Muslim immigration, especially from Saudi Arabia, the more it discredits Trump's critics. Over the last decade Khan, as an influential Washington, D.C. attorney, has insidiously erected a web of immigration infrastructure that has been used to grease the immigration process of Saudi nationals, especially those who embrace the ultra-extremist Wahhabist doctrine. Khan also co-founded the highly inflammatory Journal of Contemporary Issues in Muslim Law that advocates for Sharia and is linked to the Islamic Center of Geneva, Switzerland, an arm of the fundamentalist Muslim Brotherhood.
The massive, hidden underside of the radical Islamist iceberg is sustained by people like Khizr Khan who exploit the uncritical blanket of constitutionally protected religious freedom to infiltrate Western cultural institutions and political infrastructure.
In challenging Khan's legitimacy, Donald Trump truly shattered the mother of all glass ceilings, while trouncing the venerated nifty-fifty safe-zone grantors. It should be disturbing that Trump seems to be the only one who grasps the imminence and magnitude of the threat of Islamic terrorism to American lives.
Ironically WPTV showed an image Seddique Mateen, the father of Orlando mass shooter Omar Mateen sitting behind Hillary Clinton's podium at a campaign event near Orlando. Mr. Mateen is an outspoken supporter of the Taliban and the imposition of Sharia law. Just before the Orlando massacre Mateen was recorded uttering the "G-d will deal with gays" epithet.
Mateen has endorsed Hillary Clinton for president. It will be interesting to see if any of the nifty-fifty safe-zone grantors call on Clinton to denounce Mateen's endorsement. I wouldn't hold my breath.


They address needs and opportunities in relation to the economy, housing, community facilities and infrastructure as well as provide a basis for safeguarding the environment, adapting to climate change and securing good design.
criteria-based policies which, together with policies in any neighbourhood plans, act as the start point for considering whether planning applications should be approved.
Local plans must be justified, effective, consistent with national policy and positively prepared to deliver sustainable development that meets objectively assessed development and infrastructure needs of the area, including any unmet needs of neighbouring areas.
They are drawn up in consultation with local communities, businesses, infrastructure providers and other interested parties.