text:
Myka Stauffer: Backlash After YouTubers Give Up Adopted Son
A couple who documented on a popular YouTube channel their life with an autistic toddler adopted from China are facing a backlash after they revealed he had been placed with another family.
Myka Stauffer and her husband James, based in Ohio, produced videos about Huxley's adoption and his challenges.
Since 2017 the couple received sponsorship deals and video revenue.
While some understood the decision, critics accused the pair of exploiting Huxley to build their YouTube career.
The news that Huxley is living permanently with another family was revealed on Tuesday after followers noticed he had not been seen in a video for some time.
The couple said unspecified behavioural issues from Huxley had made life too difficult for the family, which includes four other children.
Content on the couple's YouTube account The Stauffer Life has now been deleted.
"Extremely depressed reading about the influencer who raised funds to adopt a son, made this her 'brand,' discovered he has special needs, secretly rehomed him, " wrote journalist Sophie Ross on Twitter.
Adopted children "aren't a dog you adopted from the pound that you get to return in 14 days if they aren't a good fit… gross", commented another Twitter user, one of thousands to post negative reaction.
The couple began sharing videos about their family life in 2014 and Mrs Stauffer's own YouTube channel Myka Stauffer grew to more than 700,000 subscribers this year.
In July 2016 they announced plans to adopt a toddler from China, and that they were considering adopting a second from "Uganda or Ethiopia".
The adoption agency told them Huxley had "brain damage", Mrs Stauffer wrote in a magazine article. After hesitating, the couple decided to proceed when "God softened our hearts", she wrote.
They said revenue from sponsored videos would pay for the adoption. They also asked followers to donate $5 towards supporting their son's needs, promising to write donors' names in a baby book.
One video of the family going to China to meet two-year-old Huxley was extremely popular and clocked up more than 5.5 million views on YouTube.
Tapping into the popular trend of family life videos, the couple produced hours of content documenting their son and his life following adoption.
Detailed updates on Huxley's developmental progress were included, as well as clips of him.
Other videos on the couple's YouTube and Instagram accounts included advice about pregnancy (the couple had two more children after adopting Huxley), home-schooling, decoration and household chores.
Mrs Stauffer was also interviewed in magazines about caring for children with disabilities.
Companies including Glossier and Good American offered sponsorship deals, and the birth of their fifth child was featured in People magazine in 2019.
Huxley out of sight
In September 2019, Mrs Stauffer posted an update in which she said that Huxley had received treatment following a diagnosis of autism.
But followers noticed that in late 2019 and early 2020, Huxley stopped appearing in the videos.
On Tuesday, the couple posted an update in which they explained Huxley had been given permanently to another family for the sake of his "emotional well-being".
The adoption agency had not given them the full picture about Huxley's health, they said, and doctors in the US said he now needed "a different fit in his medical needs".
"I can't explain the amount of effort Myka has put into helping Huxley," Mr Stauffer added.
Some who have followed the story for a while commented with messages of support. "I respect you so much for having the courage to make such a heartbreaking and hard decision," one wrote.
But others accused the couple of "getting rid" of Huxley after making money from his experiences.
Others expressed sympathy for him. "Although I am sure this is hard for all involved, it does not even compare to the loss this child has endured," one wrote.
The incident has again raised the issue of international adoptions whereby parents give up care of the children after a period of time, several people commented.
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\section{Introduction}
\label{sec1}
Physical models of collisionless plasmas can be roughly divided into two types: fluid and kinetic models. The magneto-hydrodynamics (MHD) model is by far the most widely-used model in the plasma community. It describes large-scale and low-frequency plasma phenomena and is suitable for macroscopic numerical simulations. The drawback of MHD is that it completely ignores the small-scale kinetic physics, which sometimes plays a role even for the global dynamics. One such example is magnetic reconnection. Although it is essentially an MHD phenomenon, the dynamics of collisionless magnetic reconnection may be governed by small-scale physics that breaks the frozen-in condition in the close vicinity of the diffusion region. Therefore, even the global consequence might be regulated largely by kinetic physics. Such kinetic effect at a small scale is often modeled phenomenologically in MHD by using \textit{ad hoc} anomalous resistivity. The validity of such treatment has always been a matter of debate. It is possible to extend MHD to include the Hall and the finite electron inertial effects within the fluid model framework. However, a fluid model in the conventional sense lacks collisionless wave-particle interactions in hot plasmas such as Landau and cyclotron resonances.

Kinetic models, on the other hand, solve the Vlasov equation at least for one of the species and can simulate fully collisionless dynamics. The particle-in-cell (PIC) method is the most popular simulation method, which employs a large number of super-particles to represent the velocity distribution function. PIC naturally requires much more computational power than fluid models because of the large degrees of freedom to represent arbitrary distribution functions. Furthermore, a fully kinetic explicit PIC code, in which both ions and electrons are treated as particles, has a severe limitation for the grid size. The Vlasov simulation, which is free from the limitation on the grid size, solves the Vlasov equation directly using mesh in phase space and is an alternative to the PIC method. Although it has a better convergence property than a PIC code that includes discrete particle noise, the additional mesh in velocity space increases the required computational resources even further. In any case, a fully kinetic treatment demands prohibitively large computational power for accurate and long-term numerical modeling for macroscopic phenomena.

The problem in collisionless plasma modeling is that one has to adopt either a fluid or fully kinetic model in the first place. Once the choice has been made, conventional fluid models ignore much of the collisionless effect, whereas the fully kinetic model tries to include everything. The huge gap in the degree of approximation between them makes it difficult to interpret the differences. It would be desirable to develop an intermediate model in which the kinetic effects such as wave-particle interactions are included approximately, possibly with a modest increase in the computational cost, so that macroscopic numerical modeling is still possible. In addition, one might hope that such a model ease the complexity of theoretical analyses because of reduced degrees of freedom.

One of the possible directions is to incorporate some of the kinetic effects approximately into a fluid model. \citet{Hammett1990} developed a scheme to take into account the collisionless Landau damping effect for electrostatic waves in a fluid model. It is well known that a fluid model can be systematically derived from the Vlasov equation by taking velocity moments, which yields an infinite series of moment hierarchy. The moment equations must be closed by appropriate choice of closure relations. The resonant wave-particle interaction effect will be completely lost unless the closure is carefully designed \citep{Hammett1992}. Physically, the resonance effect is associated with collisionless phase mixing (or particle free streaming) that requires a non-local closure. The so-called Landau closure proposed by \citet{Hammett1990} approximates the highest moment in the hierarchy (as a result of truncation) by a linear combination of lower-order moments in wavenumber space so that it retains non-local nature. By choosing appropriate coefficients such that the fluid response against perturbation approximates the fully kinetic response, one may obtain a linear dispersion relation that includes the Landau damping effect.

The Landau closure has also been incorporated into anisotropic MHD in the low-frequency limit \citep{Snyder1997}. Such a model sometimes referred to as kinetic MHD or collisionless MHD, better describes low-frequency linear kinetic instabilities. For instance, the non-local heat flux parallel to the ambient magnetic field as represented by the Landau closure algorithm has been shown to yield the correct threshold for the mirror instability, which is not the case in the standard Chew-Goldberger-Low (CGL) equation of state (EoS) \citep{Chew1956}. The realistic modeling capability of the temperature anisotropy effect is believed to be important for the collisionless system even at macroscopic scale sizes. One of the possible astrophysical applications is the dynamics of collisionless accretion disks around black holes, which has been investigated using a collisionless MHD model \citep{Sharma2003,Sharma2006}.

Although various extensions of the Landau closure beyond MHD have been proposed \citep{Goswami2005,Passot2007,Passot2012,Sulem2015}, none of them are able to reproduce the cyclotron resonance. It is perhaps because many of these models are mainly intended for application to fusion plasmas, where the background magnetic field is so strong and high-frequency electromagnetic fluctuations are not relevant. On the other hand, space and astrophysical plasmas are often in a high plasma beta state, and the cyclotron resonance appears to be of great importance in many applications. In this paper, we present a model to take into account the cyclotron resonance effect for electromagnetic waves propagating parallel to the ambient magnetic field in a collisionless plasma. We have applied the same procedure as the original Landau closure to the heat flux components associated with the transverse electromagnetic fluctuations. We demonstrate that the resulting dispersion relation approximately reproduces the cyclotron damping effect. The model is also able to predict an instability driven by finite temperature anisotropy. Furthermore, nonlinear simulation of the anisotropy-driven instability shows that the model describes not only the linear growth phase but also the relaxation and the saturation in the nonlinear phase. The relaxation process may be understood in terms of quasi-linear theory. We argue that incorporating a non-local closure is essential to describe linear and nonlinear collisionless plasma responses.

This paper is organized as follows. In section \ref{sec2}, we derive a fluid model by taking velocity moments of the Vlasov equation and point out the importance of the closure for the fluid-Maxwell coupled system of equations. The non-local closure model is introduced in section \ref{sec3}. Nonlinear simulation results obtained with the proposed model are discussed in section \ref{sec4}. Finally, discussion and conclusions are given in section \ref{sec5}.

\section{Fluid models of plasmas}
\label{sec2}
We start from the Vlasov equation describing the evolution of the velocity distribution function $f_s = f_s(\bm{x}, \bm{v})$ for a particle species $s$ ($i$ for ions and $e$ for electrons) with charge $e_s$ and mass $m_s$:
\begin{equation}
\frac{\partial f_s}{\partial t}+\bm{v}\cdot\nabla f_s+\frac{e_s}{m_s}(\bm{E}+\bm{v}\times\bm{B})\frac{\partial f_s}{\partial \bm{v}}=0,
\label{Vlasoveq}
\end{equation}
where $\bm{E}$ and $\bm{B}$ are the electric and magnetic fields, respectively. We define the following moment quantities: the number density $n_s=\int f_s d^3v$, bulk velocity $\bm{u}_s=\int \bm{v} f_s d^3v/n_s$, pressure tensor $\bm{p}_s=m_s \int (\bm{v}-\bm{u}_s)(\bm{v}-\bm{u}_s) f_s d^3v$, and heat flux tensor $\bm{q}_s=m_s \int (\bm{v}-\bm{u}_s)(\bm{v}-\bm{u}_s)(\bm{v}-\bm{u}_s) f_s d^3v$. Taking velocity moments of the Vlasov equation up to second order, we obtain the following equations:
\begin{eqnarray}
\frac{\partial n_s}{\partial t}+\nabla\cdot(n_s\bm{u}_s)=0,
\label{continuity}\\
\frac{\partial \bm{u}_s}{\partial t}+\bm{u_s}\cdot\nabla\bm{u_s}
+\frac{1}{m_sn_s}\nabla\cdot\bm{p}_s-\frac{e_s}{m_s}(\bm{E}+\bm{u}_s\times\bm{B})=0,
\label{EOM} \\
\frac{\partial \bm{p}_s}{\partial t}+\nabla\cdot(\bm{p}_s\bm{u}_s+\bm{q}_s)
+\left(\bm{p}_s\cdot\nabla\bm{u}_s+\frac{e_s}{m_s}\bm{B}\times\bm{p}_s\right)^{\mathcal{S}}=0,
\label{pressureeq}
\end{eqnarray}
where the superscript $^{\mathcal{S}}$ denotes symmetrization of a tensor: $\bm{a}^{\mathcal{S}}=\bm{a}+\bm{a}^{\mathsf{T}}$. Note that we define the divergence of a tensor by $(\nabla\cdot\bm{A})=\partial_N A_{ijk\ldots N}$, i.e., the summation is taken along the last index.

Maxwell's equations are given by
\begin{eqnarray}
\nabla\cdot\bm{B}=0, \label{M1} \\
\frac{\partial \bm{B}}{\partial t}=-\nabla\times\bm{E}, \label{M2}\\
\nabla\cdot\bm{E}=\frac{\rho}{\epsilon_0}, \label{M3} \\
\nabla\times\bm{B}=\mu_0\left(\bm{j}+\epsilon_0\frac{\partial \bm{E}}{\partial t}\right), \label{M4}
\end{eqnarray}
where $\epsilon_0$ and $\mu_0$ are the permittivity and permeability in vacuum, which define the speed of light $c=1/\sqrt{\epsilon_0 \mu_0}$. The fluid quantities and the electromagnetic fields are coupled through the charge and current densities defined by
\begin{eqnarray}
\rho=\sum_s e_sn_s, \\
\bm{j}=\sum_s e_sn_s\bm{u}_s.
\end{eqnarray}
Once the charge and current densities are given, Maxwell's equations can readily be solved.

The moment equations (\ref{continuity}-\ref{pressureeq}), however, have a number of unknowns larger than the number of equations. In other words, there is no equation to determine the heat flux $\bm{q}$. Although one could proceed to take the third-order moment of the Vlasov equation to obtain the equation for the heat flux, the fourth-order moment quantity will appear in the equation. In this way, the moment hierarchy will never close by itself, which is called the closure problem. One has to truncate the hierarchy at some point and adopt some assumptions to determine the highest-order moment. It is important to understand that the infinite series of moment equations and the original Vlasov equation are mathematically equivalent. It is the closure assumption involving truncation of the hierarchy that introduces the crucial difference between the moment equations and the fully kinetic equation. Therefore, developing a good closure model is a reasonable and straightforward strategy to incorporate the kinetic effects into a fluid model.

The simplest possible choice is to ignore the heat flux and assume an EoS to determine the pressure. The adiabatic EoS (or the polytropic law with a polytropic index $\gamma$) has been the most widely-used one to determine the scalar pressure:
\begin{equation}
\frac{d}{dt}\left(\frac{p_s}{n_s^{\gamma}} \right)=0,
\end{equation}
where the scalar pressure is defined by $p_s = \mathrm{Tr}(\bm{p}_s)/3$. Most of MHD, Hall-MHD, two-fluid, as well as multi-fluid codes routinely used today in numerical plasma modeling, are based on the simplest EoS. Note that the closure problem is quite generic and inherent in the fluid model, which can be applied independently to any species one-by-one. It is nothing to do with other approximations such as the charge neutrality assumption, various approximations for the generalized Ohm's law, etc.

One may relax the assumption of the scalar pressure. For instance, if the pressure is gyrotropic (or symmetric in the plane perpendicular to the magnetic field), the parallel and perpendicular (with respect to the magnetic field) pressures may evolve independently. The CGL EoS, which assumes the conservation of first and second adiabatic invariants, is a popular choice to determine the anisotropic pressure. It is even possible to consider the evolution of finite non-gyrotropic components, which are known to play a role in collisionless magnetic reconnection \citep{Hesse1993,Hesse1994}.

We should emphasize that none of these models mentioned above take into account the collisionless wave-particle interaction effect which requires a non-local closure. The Landau closure takes into account the non-local nature of collisionless plasmas and is able to approximate the Landau resonance effect in a fluid model. However, existing models derive the closure relation considering only the particle motion parallel to the magnetic field in the electrostatic limit or in electromagnetic fluctuations in the low-frequency limit using the guiding-center approximation. Consequently, there has been no model that includes the cyclotron resonance effect, which obviously involves both high-frequency electromagnetic fluctuations and fast cyclotron motion.

In the following section, we use the moment equations (\ref{continuity}-\ref{pressureeq}) involving the full $3\times3$ pressure tensor and the underlying full Vlasov equation (\ref{Vlasoveq}) for constructing the closure. In contrast to previous works, no approximation has been made on the wave frequency or the particle trajectory in the basic equations. We see that the same approach as the Landau closure applied to the basic equations yields a reasonable approximation to the cyclotron resonance effect as naturally expected.

\section{Closure in wavenumber space}
\label{sec3}

We now discuss the closure to determine the heat flux $\bm{q}$. Note that the subscript $s$ for particle species will be omitted whenever obvious. We let the ambient magnetic field be in the $z$ direction $\bm{B}_0=B_0\bm{e}_z$ and consider parallel propagation $\bm{k}=k\bm{e}_z$ which is equivalent to $\partial/\partial x=\partial/\partial y=0$. We work in the rest frame of the fluid $(\bm{u}_0=\bm{0})$ and assume that the plasma is homogeneous in the unperturbed state with a gyrotropic pressure: $p_{xy} = p_{xz} = p_{yz} = 0, p_{xx} = p_{yy} = p_{\perp0}, p_{zz} = p_{\parallel0}$. The linearized set of moment equations (\ref{continuity}-\ref{pressureeq}) are then given by:
\begin{align}
 & \frac{\partial \tilde{n}}{\partial t} +
 n_0\frac{\partial \tilde{u}_z}{\partial z}=0,
 \label{cont}\\
 & \frac{\partial \tilde{u}_x}{\partial t} +
 \frac{1}{mn_0}\frac{\partial \tilde{p}_{xz}}{\partial z} -
 \frac{e}{m}(\tilde{E}_x+\tilde{u}_yB_0)=0,
 \label{eomx}\\
 & \frac{\partial \tilde{u}_y}{\partial t} +
 \frac{1}{mn_0}\frac{\partial \tilde{p}_{yz}}{\partial z} -
 \frac{e}{m}(\tilde{E}_y-\tilde{u}_xB_0)=0,
 \label{eomy}\\
 & \frac{\partial \tilde{u}_z}{\partial t} +
 \frac{1}{mn_0}\frac{\partial \tilde{p}_{zz}}{\partial z} -
 \frac{e}{m}\tilde{E}_z=0,
 \label{eomz}\\
 & \frac{\partial}{\partial t} \tilde{p}_{xx}
 + p_{\perp0} \frac{\partial}{\partial z} \tilde{u}_{z}
 + \frac{\partial}{\partial z} \tilde{q}_{xxz}
 - 2 \frac{e}{m} B_0 \tilde{p}_{yx} = 0,
 \label{pxx}\\
 & \frac{\partial}{\partial t} \tilde{p}_{yy}
 + p_{\perp0} \frac{\partial}{\partial z} \tilde{u}_{z}
 + \frac{\partial}{\partial z} \tilde{q}_{yyz}
 + 2 \frac{e}{m} B_0 \tilde{p}_{xy} = 0,
 \label{pyy}\\
 & \frac{\partial}{\partial t} \tilde{p}_{zz}
 + 3 p_{\parallel0} \frac{\partial}{\partial z} \tilde{u}_{z}
 + \frac{\partial}{\partial z} \tilde{q}_{zzz} = 0,
 \label{pzz}\\
 & \frac{\partial}{\partial t} \tilde{p}_{xy}
 + \frac{\partial}{\partial z} \tilde{q}_{xyz}
 + \frac{e}{m} B_0 \left( \tilde{p}_{xx} - \tilde{p}_{yy} \right) = 0,
 \label{pxy}\\
 & \frac{\partial}{\partial t} \tilde{p}_{xz}
 + p_{\parallel0} \frac{\partial}{\partial z} \tilde{u}_{x}
 + \frac{\partial}{\partial z} \tilde{q}_{xzz}
 - \frac{e}{m} \tilde{B}_{y} \left( p_{\perp0} - p_{\parallel0} \right)
 - \frac{e}{m} B_0 \tilde{p}_{yz} = 0,
 \label{pxz}\\
 & \frac{\partial}{\partial t} \tilde{p}_{yz}
 + p_{\parallel0} \frac{\partial}{\partial z} \tilde{u}_{y}
 + \frac{\partial}{\partial z} \tilde{q}_{yzz}
 + \frac{e}{m} \tilde{B}_{x} \left( p_{\perp0} - p_{\parallel0} \right)
 + \frac{e}{m} B_0 \tilde{p}_{xz} = 0.
 \label{pyz}
\end{align}
All the first-order perturbations are denoted by $~\tilde{}~$. Observe that these equations may be split into the longitudinal and transverse components: The longitudinal components involve the field-aliened flow $\tilde{u}_z$ whereas the transverse components are independent of that.

The dynamics associated with electrostatic waves are described by $\tilde{n}, \tilde{u}_z, \tilde{p}_{zz}$ for which the original Landau fluid closure proposed by \citet{Hammett1990} may be used. The perpendicular pressure perturbations $\tilde{p}_{xx}, \tilde{p}_{yy}, \tilde{p}_{xy}$ (recall the symmetry of pressure tensor $\tilde{p}_{xy} = \tilde{p}_{yx}$) are dependent only passively on $\tilde{u}_z$. They describe essentially the cyclotron motion of the perturbed pressure, which decouple from the other dynamics unless physically unreasonable assumptions on the heat flux $\tilde{q}_{xxz}, \tilde{q}_{yyz}, \tilde{q}_{xyz}$ are adopted. In the following, we assume that the transverse components $\tilde{u}_{x}, \tilde{u}_{y}, \tilde{p}_{xz}, \tilde{p}_{yz}$ are decoupled from the longitudinal dynamics.

At first, we consider the case with an isotropic zeroth-order pressure tensor $\bm{p}_{0}=p_{0}\bm{1}$; extension to the anisotropic case $(p_{\perp0}\neq p_{\parallel0})$ will be discussed later. Fourier transformation of Eqs. (\ref{eomx}), (\ref{eomy}), (\ref{pxz}), and (\ref{pyz}) gives

\begin{eqnarray}
-i\omega \tilde{u}_x + ik\tilde{p}_{xz}/mn_0-\frac{e}{m}(\tilde{E}_x+\tilde{u}_yB_0)=0,\\
-i\omega \tilde{u}_y + ik\tilde{p}_{yz}/mn_0-\frac{e}{m}(\tilde{E}_y-\tilde{u}_xB_0)=0,\\
-i\omega \tilde{p}_{xz}+ik(p_0\tilde{u}_x+\tilde{q}_{xzz})-\frac{eB_0}{m}\tilde{p}_{yz}=0,\\
-i\omega \tilde{p}_{yz}+ik(p_0\tilde{u}_y+\tilde{q}_{yzz})+\frac{eB_0}{m}\tilde{p}_{xz}=0.
\end{eqnarray}
We assume the following form of $\tilde{q}_{xzz}$ and $\tilde{q}_{yzz}$:
\begin{equation}
\begin{cases}
\tilde{q}_{xzz}=\Pi\tilde{u}_x+\nu\tilde{p}_{xz},\\
\tilde{q}_{yzz}=\Pi\tilde{u}_y+\nu\tilde{p}_{yz},
\end{cases}
\label{defhf}
\end{equation}
here $\Pi$ and $\nu$ are free parameters having dimensions of pressure and velocity, respectively.
Although this form is not unique,
this results in decomposition of eigenmodes corresponding to the cold plasma limit after diagonalization.
At this point, they can be functions of wavenumber $k$ but we later find that only the sign of $\nu$ changes depending on the sign of $k$. From these equations, we obtain the relationship between $(\tilde{u}_x\,\tilde{u}_y)^{\mathsf{T}}$ and $(\tilde{E}_x\,\tilde{E}_y)^{\mathsf{T}}$:
\begin{equation}
\begin{pmatrix}
-i\omega' & -\Omega'\\
\Omega' & -i\omega'
\end{pmatrix}
\begin{pmatrix}
\tilde{u}_x\\
\tilde{u}_y
\end{pmatrix}
=
\frac{e}{m}
\begin{pmatrix}
\tilde{E}_x\\
\tilde{E}_y
\end{pmatrix},
\end{equation}
where we have introduced the definition
\begin{equation}
\begin{cases}
\omega'=\omega\left(1-\frac{p_{0}+\Pi}{n_0m}\frac{\omega-k\nu}{\omega}\frac{k^2}{(\omega-k\nu)^2-\Omega^2}\right),\\
\Omega'=\Omega\left(1+\frac{p_{0}+\Pi}{n_0m_s}\frac{k^2}{(\omega-k\nu)^2-\Omega^2}\right),
\end{cases}
\end{equation}
with $\Omega=eB_0/m$ being the cyclotron frequency. Notice that the cold plasma result is recovered in the
cold or long-wavelength limit ($p_0+\Pi\to 0$ or $k\to 0$). We may obtain the current density by calculating the inverse matrix and taking the sum over all species. We introduce quantities such as
$\hat{q}=\tilde{q}_{xzz}+i\tilde{q}_{yzz}$, $\hat{u}=\tilde{u}_x+i\tilde{u}_y$,
and $\hat{p}=\tilde{p}_{xz}+i\tilde{p}_{yz}$
to diagonalize the matrix, which, together with Maxwell's Eqs. (\ref{M2}), (\ref{M4}), gives the following dispersion relation.
\begin{equation}
1-\frac{c^2k^2}{\omega^2}-\sum_s \frac{\omega_{ps}^{2}}{\omega(\omega'_s-\Omega'_s)}=0,
\end{equation}
where $\omega_{ps}=\sqrt{(n_0e_s^2)/(m_s\epsilon_0)}$ is the plasma frequency. In this form, positive (negative) $\mathrm{Re}[\omega]$ corresponds to left-hand (right-hand) circular polarization, respectively. Note that Eq. (\ref{defhf}) can be rewritten as follows
\begin{equation}
\hat{q}=\Pi\hat{u}+\nu\hat{p}. \label{redefhf}
\end{equation}

The corresponding fully kinetic dispersion relation is given by
\begin{equation}
1-\frac{c^2k^2}{\omega^2}+\sum_s \frac{\omega_{ps}^{2}}{\sqrt{2}\omega|k|v_{\mathrm{th},s}}
Z\left(\frac{\omega-\Omega_s}{\sqrt{2}|k|v_{\mathrm{th},s}}\right)=0,
\end{equation}
where $v_{\mathrm{th},s}=\sqrt{p_{0,s}/(n_0m_s)}$ is the thermal velocity and $Z(\zeta)$ is the plasma dispersion function with argument $\zeta$ \cite{Stix}. Therefore, our task is to find the values of $\Pi$ and $\nu$ so that
\begin{equation}
-\frac{1}{(\omega'_s-\Omega'_s)}
\sim\frac{1}{\sqrt{2}|k|v_{\mathrm{th},s}}Z\left(\frac{\omega-\Omega_s}{\sqrt{2}|k|v_{\mathrm{th},s}}\right)
\end{equation}
is approximately satisfied.
Writing $a=k\nu_s/(\sqrt{2}|k|v_{\mathrm{th},s}),b=1/2+\Pi_s/(2p_{0,s})$ and $\zeta_s=(\omega-\Omega)/(\sqrt{2}|k|v_{\mathrm{th},s})$, we see
\begin{equation}
-\frac{1}{(\omega'_s-\Omega'_s)}=-\frac{1}{\sqrt{2}|k|v_{\mathrm{th},s}}\frac{\zeta_s-a}{\zeta_s^2-a\zeta_s-b}.
\end{equation}
By matching the first two terms of the Taylor series expansion of the rational function and $Z(\zeta)$
\begin{equation}
Z(\zeta)=i\sqrt{\pi}-2\zeta-\cdots ,
\end{equation}
we obtain
\begin{equation}
\begin{cases}
a=-\frac{i\sqrt{\pi}}{\pi-2},\\
b=\frac{1}{\pi-2}.
\end{cases}
\end{equation}
For $|\zeta|\gg1$, we have already seen that this model approaches the cold plasma limit which is consistent with the asymptotic form of $Z(\zeta)$
\begin{equation}
Z(\zeta)=-\frac{1}{\zeta}-\frac{1}{2\zeta^3}-\cdots .
\end{equation}

The resulting dispersion relation for $m_i/m_e=1836, \beta_i=\beta_e=1, (\beta_s=p_{0,s}/(B_0^2/2\mu_0))$ is shown and compared with the fully kinetic results in FIG. \ref{l},\ref{r}. Inertial length of each species are denoted by $\lambda_s=c/\omega_{ps}$. Note that we have assumed $kc/\omega\gg1$ which is a good approximation if $\omega_{ps}/\Omega_s\gg1$ is satisfied for both ions and electrons.  They both capture the effect of cyclotron damping characteristics of collisionless magnetized plasmas. Notice the normalization and scales of both axes are different in these figures.
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig1.pdf}
\caption{\label{l} Dispersion relation of left-handed polarized mode obtained with $\beta_i=\beta_e=1$.
The blue color indicates the result obtained by the proposed closure method, whereas the red color indicates the fully kinetic theory.}
\end{center}
\end{figure}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig2.pdf}
\caption{\label{r} Dispersion relation of right-handed polarized mode obtained with $\beta_i=\beta_e=1$ with the format same as FIG. \ref{l}.
Note that negative frequency $-\mathrm{Re}[\omega]$ is plotted for the real part.}
\end{center}
\end{figure}
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig3.pdf}
\caption{\label{anomalous} Damping rate of right-handed polarized mode near ion inertial wavelength obtained with $\beta_i=\beta_e=1$.
The black dashed line indicates the result obtained with the cold ions $(\beta_i=0)$.}
\end{center}
\end{figure}
Let us see the details of the damping rate for the right-handed polarized mode. FIG. \ref{anomalous} provides the enlarged view for the damping rate of the right-handed polarized mode at wavelengths comparable to the ion inertial length. The damping rate obtained with the cold ion approximation $(\beta_i=0)$ is also shown in black for comparison. From this, we see the damping at this scale is associated with the ion cyclotron resonance. Although the closure model gives a somewhat larger damping rate, it correctly predicts the qualitative characteristics of the mode. It is rather more important that the error in this model keeps the system stable because otherwise, such a model can be unstable for nonlinear simulations where multiple different modes coexist and interact with each other. In section \ref{sec4}, we will see that a nonlinear simulation based on this model has been conducted without any unwanted instabilities.

Let us now consider finite zeroth-order pressure anisotropy:
\begin{equation}
\bm{p}_{0,s}=\mathrm{diag}(p_{\perp0,s},p_{\perp0,s},p_{\parallel0,s}).
\end{equation}
Note that, as we can see from Eqs.~(\ref{pxz}-\ref{pyz}), this introduces extra terms into the equations for $\tilde{p}_{xz}, \tilde{p}_{yz}$. With the same closure ($p_{\parallel0}$ now replaces $p_0$), we have the following dispersion relation:
\begin{equation}
1-\frac{c^2k^2}{\omega^2}-\sum_s \frac{\omega_{ps}^{2}}{\omega}
\left(\frac{1}{\sqrt{2}|k|v_{\mathrm{th},s}}\frac{\zeta_s-a}{\zeta_s^2-a\zeta_s-b}
+\frac{A_s}{2\omega}\frac{1}{\zeta_s^2-a\zeta_s-b}\right)=0,\label{anisodisp}
\end{equation}
where $A_s=p_{\perp 0,s}/p_{\parallel 0,s}-1$ represent the anisotropy.
The fully kinetic dispersion relation for parallel propagation in bi-Maxwellian plasmas is given by \cite{Stix}
\begin{equation}
1-\frac{c^2k^2}{\omega^2}+\sum_s \frac{\omega_{ps}^{2}}{\omega}
\left[\frac{1}{\sqrt{2}|k|v_{\mathrm{th},s}}Z(\zeta_s)
+\frac{A_s}{\omega}\left(1+\zeta_s Z(\zeta_s)\right)\right]=0.\label{kinemic}
\end{equation}
Comparison between Eq. (\ref{anisodisp}) and (\ref{kinemic}) is shown in FIG. \ref{emic} with the same parameters used by \citet{Davidson1975}: $m_i/m_e=1836, \beta_{\perp,i}=1, \beta_{\parallel,i}=0.2, 3\beta_e/2=\beta_{\perp,i}+\beta_{\parallel,i}/2$ (the result is not sensitive to electron parameters).
\begin{figure}[H]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig4.pdf}%
\caption{\label{emic} Dispersion relation of EMIC anisotropy instability obtained with $\beta_{\perp,i}=1,\beta_{\parallel,i}=0.2$.
The format is the same as FIG. \ref{l}}
\end{center}
\end{figure}
Although the Taylor expansion of the second term introduced by finite anisotropy $(1/(\zeta_s^2-a\zeta_s-b))$ does not agree with the corresponding term obtained from the fully kinetic theory $(1+\zeta_s Z(\zeta_s))$ even for the lowest order term, the closure model gives a qualitatively correct result. In principle, it is possible to modify the closure for a better approximation for finite $A\neq0$. However, that would introduce extra error on the first term, which we find undesirable. As we will see in the next section, the anisotropy will often evolve in time. Therefore, fine-tuning for a particular set of parameters is not necessarily useful in practice. Though we use the same $a,b$ for isotropic and anisotropic cases, we think it is sufficient because the dispersion relation obtained from this closure still predicts qualitatively the same behavior found in the fully kinetic model.

\section{Nonlinear simulation}
\label{sec4}
\subsection{Simulation model and numerical method}
In this section, we present nonlinear simulation results obtained by a model based on the proposed closure. Since the closure may independently be applied to any particle species, we consider only the ion dynamics for simplicity. In other words, electrons are treated as a massless, isothermal, and isotropic fluid. For ions, we solve Eqs. (\ref{continuity}-\ref{pressureeq}) with the non-local heat flux as detailed below. We assume that $p_{xx}=p_{yy}$ and $p_{xy}=0$ are always satisfied so that extra closure equations for these terms are not needed. We solve $p_{\perp}=(p_{xx}+p_{yy})/2$ instead of solving $p_{xx}$ and $p_{yy}$ separately. Henceforth, we denote $p_{zz}=p_{\parallel}$ for notation consistency. This makes the model an eight-moment model, while scalar and gyrotropic pressure (such as CGL-MHD) models may be categorized as five-moment and six-moment models, respectively.

The electric field is then determined by the generalized Ohm's law
\begin{equation}
\bm{E}+\bm{u}\times\bm{B}=-\frac{1}{en}\bm{B}\times(\nabla\times\bm{B})-\frac{T_e}{en}\nabla n
\end{equation}
where $T_e$ is the electron temperature and charge neutrality is assumed: $n=n_i\sim n_e$. We ignore the displacement current term of Eq. (\ref{M4}) to be consistent with the charge neurtality assumption. This provides a good approximation if we only consider wave length sufficiently longer than Debye length in the system whose electron plasma frequency is sufficiently larger than electron cyclotron frequency. The time evolution of the magnetic field is calculated by Eq. (\ref{M2}). If we use the standard adiabatic EoS for a scalar ion pressure, this model is identical to Hall-MHD.

We use a one-dimensional simulation box with the periodic boundary condition. All the physical quantities are transformed to Fourier coefficients using Fast Fourier Transform, then required derivatives and heat flux terms are calculated in the Fourier space; differentiation is simply multiplication by $ik$ in the Fourier space.

The transverse heat flux terms are calculated directly in Fourier space by Eq. (\ref{redefhf}) with
\begin{equation}
\begin{cases}
\nu=-iv_{\mathrm{th}}\frac{\sqrt{2\pi}}{\pi-2}\frac{k}{|k|},\\
\Pi=\frac{4-\pi}{\pi-2}.
\end{cases}
\end{equation}
The Landau closure is used for the longitudinal heat flux:
\begin{equation}
\tilde{q}_{zzz}=-i\sqrt{\frac{8}{\pi}}v_{\mathrm{th}}
\left(\tilde{p}_{\parallel}-\frac{p_{\parallel0}}{n_0}\tilde{n}\right)\frac{k}{|k|}.
\end{equation}
These quantities are brought back to $z$-space to evaluate the nonlinear terms via transform method. The resulting equations in the semi-discrete form are integrated by fourth-order explicit Runge-Kutta method.

\subsection{Simulation setup}
Here, we consider an instability driven by perpendicular temperature anisotropy $(T_{\perp}>T_{\parallel})$, which destabilizes EMIC waves. We use the same parameter as FIG. \ref{emic} $(\beta_{\perp}=1,\beta_{\parallel}=0.2)$. The initial condition is uniform in space except for small random noise added on to the transverse magnetic field ($\sim0.01\%$ of the ambient field). We use $\Delta z/\lambda_i=0.25, \Omega_{ci}\Delta t =0.01$ for space and time discretization. The size of the simulation box is $L_z=64\lambda_i$. The time integration is carried out up to $\Omega_{ci}t=800$.

The total energy of this system is the sum of ion pressure: $p_{\perp}+p_{\parallel}/2$, magnetic energy: $(B_x^2+B_y^2)/2\mu_0$, and kinetic energy: $nmu^2/2$. We have confirmed that the total energy is conserved within $0.1\%$ during the entire simulation interval even though it is not a conserved quantity in a strict sense because of the assumption of the isothermal EoS for the electron fluid.

\subsection{Results}
\begin{figure}[h]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig5.pdf}%
\caption{\label{growth} Comparison between simulation results and linear theory.
The time development of Fourier amplitude $|B_x+iB_y|(k)$ for mode $+7$ and $+8$ are shown.
Note that the theoretical growth rates for the two modes are nearly the same as the maximum growth rate.}
\end{center}
\end{figure}

\begin{figure}[h]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig6.pdf}%
\caption{\label{energydensity} Evolution of energy density.
(a) Perpendicular $p_{\perp}$ and parallel $p_{\parallel}/2$ energy density.
(b) Transverse magnetic $(B_x^2+B_y^2)/2\mu_0$ (solid) and kinetic $nm(v_x^2+v_y^2+v_z^2)/2$ (dashed) energy density}
\end{center}
\end{figure}

\begin{figure}[h]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig7.pdf}%
\caption{\label{spectre} Evolution of wavenumber spectrum.
(a) Magnetic field: $|\tilde{B}_x(k,t)|/B_0$. (b) Number density: $|\tilde{n}(k,t)|/n_0$.
The color is shown in logarithmic scale.}
\end{center}
\end{figure}

FIG. \ref{growth} shows that the simulation result is consistent with the linear theory. The initial development of modes with near the maximum growth rate ($+7$ and $+8$) matches almost exactly with the theoretical prediction. We can see that the linear approximation is valid during the initial phase $(0<\Omega_{ci}t<150)$. Although the closure is constructed for linearized equations and does not guarantee the nonlinear stability, the saturation of transverse magnetic field and relaxation of pressure anisotropy are observed in FIG. \ref{energydensity}, which might seem surprising at first glance. This qualitatively correct behavior of the saturation phase $(100<\Omega_{ci}t<200)$ will be discussed in the next subsection.

Long term evolution after the saturation can be seen in FIG. \ref{spectre}. FIG. \ref{spectre} (a) suggests that the magnetic energy is gradually transferred to longer wavelength modes. This inverse cascade can be explained as a result of successive operations of the parametric decay instability, or nonlinear wave-wave interactions \cite{Goldstein1978,Terasawa1986}. We see that such a nonlinear MHD/Hall-MHD process is successfully contained in the model. The coupling between transverse electromagnetic waves and acoustic waves can be seen in FIG. \ref{spectre} (b). Although the linear growth of acoustic waves is qualitatively similar between this model and Hall-MHD (see \citet{Nariyuki2006}, however, for the effect of linear Landau damping of acoustic waves), there is an important difference in nonlinear evolution. In a typical fluid where the dissipation occurs only at the grid scale, large-amplitude acoustic waves steepen to form shocks, and the heating of plasma takes place locally at the shock surfaces. We did not observe, however, such a signature of wave steepening in the density spectrum FIG. \ref{spectre} (b). In the present model, acoustic waves suffer Landau damping, which is taken into account approximately through the Landau closure. The dissipation thus happens globally without drastic steepening of waves. This is consistent with the characteristics of short wavelength acoustic waves in sufficiently high-$\beta$ plasmas.

\subsection{Quasilinear relaxation}
\label{QR}
Let us discuss how the isotropization observed in the simulation is explained. For this purpose, we consider the diagonal components of the pressure tensor equation and the equation for kinetic energy (which is obtained by taking the inner product between $mn\bm{u}$ and Eq. (\ref{EOM}) ).
\begin{align}
\frac{\partial p_{\perp}}{\partial t}+\frac{\partial}{\partial z}(p_{\perp}u_z)
+p_{xz}\frac{\partial u_x}{\partial z}+p_{yz}\frac{\partial u_y}{\partial z}
-\frac{e}{m}(B_xp_{yz}-B_yp_{xz}) &=0, \label{perp}\\
\frac{\partial p_{\parallel}}{\partial t}+\frac{\partial}{\partial z}(p_{\parallel}u_z+q_{zzz})
+2\left[p_{\parallel}\frac{\partial u_z}{\partial z}+\frac{e}{m}(B_xp_{yz}-B_yp_{xz})\right] &=0, \label{parallel}\\
\frac{\partial}{\partial t}\left(\frac{1}{2}mnu^2\right)
+\frac{\partial}{\partial z}\left(\frac{1}{2}mnu^2u_z+p_{xz}u_x+p_{yz}u_y+p_{\parallel}u_z\right)& \nonumber \\
-\left(p_{xz}\frac{\partial u_x}{\partial z}+p_{yz}\frac{\partial u_y}{\partial z}+p_{\parallel}\frac{\partial u_z}{\partial z}\right)
-ne\bm{u}\cdot\bm{E}&=0. \label{kinetic}
\end{align}
The second terms in these equations are in conservation form and they do not affect the spatially averaged pressures. $p_{zz}\frac{\partial u_z}{\partial z}$ is the term associated with the longitudinal mode and is not relevant for isotropization. The $p_{xz}\frac{\partial u_x}{\partial z}+p_{yz}\frac{\partial u_y}{\partial z}$ in Eq. (\ref{perp}) and Eq. (\ref{kinetic}) with the opposite signs, which may be understood as the energy exchange between perpendicular energy and kinetic energy via the instability.

The remaining term $B_xp_{yz}-B_yp_{xz}$ appears in both parallel and perpendicular equations with the opposite signs (recall that $2p_{\perp}=p_{xx}+p_{yy}$). Considering the total thermal energy is given by $\frac{1}{2}\mathrm{Tr}(\bm{p})=p_{\perp}+p_{\parallel}/2$, we see that this term effectively acts as the isotropization, which may reduce the initial anisotropy and suppress the wave growth in the nonlinear phase. Now let us investigate the nonlinear isotropization term in detail. The evolution of spatially averaged $(k=0)$ pressure is associated with:
\begin{equation}
\begin{split}
(B_xp_{yz}-B_yp_{xz})_{k=0}
&=\int dk' \left[\tilde{B}_x(k')\tilde{p}_{yz}(-k')
- \tilde{B}_y(k')\tilde{p}_{xz}(-k') \right]\\
&=-\int dk'\mathrm{Im}[\hat{B}(k')\hat{p}^{\ast}(k')]
\label{bcrossp}
\end{split}
\end{equation}
where $^\ast$ denotes complex conjugate. The relation between $\hat{B}$ and $\hat{p}$ is obtained from the linearized equations:
\begin{equation}
\hat{p}=\frac{e}{m}
\frac{p_{\parallel 0}\left[\omega\left(1+\frac{\Pi}{p_{\parallel 0}}\right)
+A(\omega-\Omega)\right]}
{(\omega-\Omega-k\nu)(\omega-\Omega)-k^2v_{\mathrm{th}}^2
\left(1+\frac{\Pi}{p_{\parallel 0}}\right)} \hat{B}.
\end{equation}
Note that the linear dispersion relation $\omega=\omega(k)$ must be used to evaluate the relation. Substituting this expression to Eq. (\ref{bcrossp}), we obtain the following quasilinear approximation for the isotropization term:
\begin{equation}
\begin{split}
&\frac{e}{m}(B_xp_{yz}-B_yp_{xz})_{k=0}
=\left(\frac{e}{m}\right)^2\int dk' |\hat{B}(k')|^2\\
&\times
\mathrm{Im}\left[\frac{p_{\parallel 0}\left[\omega\left(1+\frac{\Pi}{p_{\parallel 0}}\right)
+A(\omega-\Omega)\right]}
{(\omega-\Omega-k'\nu)(\omega-\Omega)-{k'}^2v_{\mathrm{th}}^2
\left(1+\frac{\Pi}{p_{\parallel 0}}\right)}\right].
\label{QLeval}
\end{split}
\end{equation}
We can see that this term is proportional to the wave magnetic energy. It is easy to confirm that the isotropization effect disappears if $\omega$ and $\nu$ were real valued. Our choice of the closure coefficients makes this term non-zero and results in the plausible isotropization. We should mention that these properties are very similar to the standard quasilinear theory for the fully kinetic model \citep{Yoon2017}.

\begin{figure}[H]
\begin{center}
\includegraphics[width=0.75\linewidth]{fig8.pdf}%
\caption{\label{qle} Comparison between isotropization term and temporal derivative of parallel pressure.
The direct evaluation of $-e/m(B_xp_{yz}-B_yp_{xz})_{k=0}$ is shown in red, while quasilinear approximation of Eq. (\ref{QLeval}) is in blue.
The black line indicating the temporal derivative $dp_{\parallel}/dt/2$ for comparison is nearly indistinguishable from the red line.}
\end{center}
\end{figure}

FIG.\ref{qle} compares the actual spatially averaged isotropization term of Eq. (\ref{bcrossp}) and the approximation Eq. (\ref{QLeval}) calculated by taking the sum of eight dominant modes seen in the simulation $(\pm 6,\pm 7, \pm 8, \pm 9)$. The coefficient was calculated using the initial condition. We can see that the change of parallel pressure (black) is indeed dominated by the isotropization term (red). The quasi-linear approximation shown in blue slightly underestimates the isotropization term, which comes from the contributions of the wavenumbers we did not include in the summation.

This comparison indicates the validity of the quasi-linear theory described here and also that the linear phase relationship between magnetic field $\hat{B}$ and the off-diagonal pressure $\hat{p}$ has been kept up to at around $\Omega_{ci}t=130$. At this time, the anisotropy is reduced substantially from the initial condition, which introduces non-negligible deviation to the linear eigenmodes of the system.

\section{Discussion and Conclusion}
\label{sec5}
We have discussed the method to take into account the cyclotron resonance effect in a fluid model. We have started from the moment equations derived from the Vlasov equation and determined the closure coefficients in wavenumber space so that the linear response for each particle species approximates the response obtained by linear kinetic theory assuming Maxwellian as the zeroth-order distribution function. We have successfully reproduced the qualitative behavior of dispersion relation described by $Z$-function.

Looking at this from a different perspective, we may understand that the model gives the exact response obtained for a different zeroth-order distribution which mimics Maxwellian distribution \cite{Hammett1990}. This raises the possibility that similar procedures extended to higher-order moments may give reasonable approximations to more complicated non-Maxwellian distributions. In principle, we may be able to incorporate the effect of nonlinear modification of the initial distribution function into the model if we find a scheme to systematically extend the closure model to higher-order terms, which will describe more complicated "shapes" of distribution functions.

The relaxation of the temperature anisotropy through the EMIC instability we saw in Sec.~\ref{sec4} can be regarded as one of the examples in which a non-local closure model succeeded in not only linear but also nonlinear regimes, reproducing a qualitatively correct long term behavior of an initially unstable system. The isotropization effect was fed back to the closure coefficients, which suppressed the wave growth and led to saturation. To the authors' knowledge, this kind of nonlinear feedback of kinetic instabilities has never been taken into account in a similar fluid model.

The original Landau closure \citep{Hammett1990} is capable of modeling the linear Landau damping of electrostatic waves for a Maxwellian plasma. It has also been extended to electromagnetic fluctuations in the low-frequency limit \citep{Snyder1997,Goswami2005,Passot2007,Passot2012,Sulem2015}. Although they differ from each other in detail, the non-local closure coefficients were determined solely based on linear Landau resonance for the gyrotropic components. The nonlinear effect associated with the deviation from the unperturbed distribution function does not seem to be included appropriately. Indeed, a typical strategy for nonlinear collisionless MHD simulations \citep{Sharma2006,Hirabayashi2016,Hirabayashi2017} is to include artificial pitch-angle scatterings, which will be turned on if the anisotropy develops into unstable regimes because otherwise, there is nothing to suppress the kinetic instability.

Our model, on the other hand, determines the closure componentwise for the response tensor; the existing Landau closure applied to the longitudinal component, and the new closure for transverse components. Since our model does not assume anything on the wave frequency, the non-gyrotropic components of the pressure tensor cannot be ignored. We actually find that they play the essential role for the cyclotron resonance effect. The closure model proposed here gives a reasonable approximation up to the cyclotron frequency of the resonant particle species. It is a rather unexpected finding that the non-gyrotropic components, when appropriately modeled with a non-local closure, contribute to the relaxation of anisotropy. We think this result is encouraging because our approach is quite straightforward and may be extended to higher orders.

It is worth mentioning that a Landau-type closure has also been applied to the collisionless magnetic reconnection problem. It is well known that the electron non-gyrotropy is essential for breaking the magnetic field frozen-in condition in the electron diffusion region. \citet{Wang2015} and subsequent works \citep{Ng2017,Ng2020} used a ten-moment model with the full pressure tensor in their two-fluid (ions and electrons) simulations of magnetic reconnection. They naively applied the original electrostatic Landau closure for the scalar pressure to the full $3 \times 3$ tensor, which, however, does not have a solid theoretical basis. The philosophy of Landau-type closure is to approximate the fully kinetic heat flux by a linear combination of lower-order moments. The componentwise approach taken in this paper directly follows this. For the problem of collisionless magnetic reconnection, one of the possibilities is to approximate the heat flux to mimic the electron response in the linear collisionless tearing mode where the electron inertial resistivity plays the essential role.

Finally, let us discuss the potential of non-local closure fluid models for macroscopic simulations. To apply a non-local closure model to a general system that requires beyond-MHD descriptions but is too demanding for particle codes, further extensions of the model will be necessary. Obviously, an extension to higher-order moments is useful to represent more complicated distribution functions. In addition, proper treatment of oblique propagation and inhomogeneous equilibrium states needs to be worked out. The former can presumably be achieved by adopting some kind of finite-Larmor-radius (FLR) correction. Landau-fluid-based models with FLR corrections \cite{Goswami2005,Sulem2015,Sarto_2017} have a certain success in achieving a better agreement with the kinetic result for obliquely propagating modes such as the mirror instability.
Details of FLR models and application to parallel and oblique firehose instabilities are given in \citep{Hunana2019}.
The latter may require further theoretical consideration and better numerical methods.

\begin{acknowledgments}
This work was supported by JSPS KAKENHI grant Nos.~17H02966 and 17H06140.
T. J. was supported by International Graduate Program for Excellence in Earth-Space Science (IGPEES),
The University of Tokyo.
\end{acknowledgments}

\section*{data availability}
The data that support the findings of this study are available from the corresponding author
upon reasonable request.

\nocite{*}
\input{closure.bbl}

\end{document}

redpajama_set_name: RedPajamaArXiv


text:
ATLANTIC IMMIGRATION PILOT - PROGRAMS AND EMPLOYER DESIGNATION
BACKGROUNDER: ATLANTIC IMMIGRATION PILOT - PROGRAMS AND EMPLOYER DESIGNATION
As the first key initiative under the Atlantic Growth Strategy, three new employer-driven permanent residence immigration programs have been created under the Atlantic Immigration Pilot. The goal of the three-year Pilot is to help attract and retain skilled immigrants in Atlantic Canada.
With a shrinking labour force and ageing population, immigration of skilled workers is required to meet pressing labour market needs and to ensure long-term economic growth and continued success for Atlantic Canada.
All principal applicants arriving in Canada under the Pilot will have a job offer from a designated employer and an individualized settlement plan for them and their family. A job and settlement support are key to having newcomers succeed and stay in the region.
Starting in early March, 2017, Immigration, Refugees and Citizenship Canada will begin accepting permanent resident applications for the Atlantic Immigration Pilot programs. In 2017, a total of up to 2000 applications, which include the skilled worker and any family member coming with them, will be accepted for these programs.
In an innovative first, employers will be required to work with settlement service provider organizations to help newcomers to Canada integrate into their new communities in Atlantic Canada so they stay there long-term and help grow the economy in the region.
Often, economic immigrants that come to Canada don't necessarily have a job offer or a settlement plan in place before they arrive. Under this Pilot, every principal applicant will come to Atlantic Canada with a job offer and an individualized settlement plan for themself and their family, connecting them to services known to support successful integration.
Once a designated employer finds a skilled immigrant who meets their employment needs and the program criteria, they will need to first offer them a job.
In many cases a Labour Market Impact Assessment is needed for immigration purposes to show that no Canadian worker is available to do the job. To help address the pressing labour market needs of the Atlantic region, employers will not need to get a Labour Market Impact Assessment for jobs they offer to skilled workers under these new pilot programs.
After accepting the job, the employer will connect the skilled immigrant with a designated settlement service provider organization for a needs assessment and to develop a settlement plan. Employers will also support the long-term integration of the newcomer and their family so they can reach the goals of their settlement plan once they arrive in Canada.
Starting in March 2017, employers that need to fill an immediate job vacancy will also have access to a temporary work permit so the skilled immigrant and their family can come to Canada right away. To qualify for this temporary work permit, the skilled immigrants will need a valid job offer, a letter from the province and a commitment to apply for permanent residence within 90 days of the temporary work permit application.
To help determine the success of the Pilot, ongoing reporting by employers, settlement service provider organizations and provinces to Immigration, Refugees and Citizenship Canada will be in place. Details on reporting requirements will be available later in 2017.
Employer designation process
The Atlantic provinces are now accepting applications from employers that would like to hire skilled immigrants under the Pilot. Employers with locations in multiple Atlantic provinces will require separate a designation for each province.
To become designated, employers must meet certain requirements, including a commitment to support the newcomer and their family as they integrate into their new life in Atlantic Canada.
Employers can visit the websites below for information on how to apply to become a designated employer under the Pilot.
New Brunswick: www.welcomenb.ca
Nova Scotia: http://novascotiaimmigration.com/atlantic-immigration-pilot
Prince Edward Island: www.immigratepei.ca
Newfoundland and Labrador: www.nlimmigration.ca

redpajama_set_name: RedPajamaCommonCrawl


Can someone check my Gtranslate?
Hi. Can someone check my Gtranslate installation using FTP?
I've been trying to get help for a week now. I can't get any response.
Re: Can someone check my Gtranslate?
Please send the FTP access info and we will install it for you. You can use the PM button on the right to send it.


text:
function startNotification(characteristic){
    // start notifications for the given characteristic
    characteristic.startNotifications();
}

function stopNotification(characteristic){
    // stop notifications for the given characteristic
    characteristic.stopNotifications();
}

function handleNotificationData(characteristic, dataFormat){
    // generic callback for handling notification data from a characteristic
    // the array input contains information on how many bytes and how they should be read
}

function registerCharacteristic(serviceUUID, characteristicUUID){
    // generic function for registering a characteristic belonging to a specific service
}

function createEventHandler(){
    var genericEventHandler = function (event){
        logRawHexValues(event);
    }
    return genericEventHandler;
}

function logRawHexValues(event){
      let value = event.target.value;
      let a = [];
      // Convert raw data bytes to hex values just for the sake of showing something.
      // In the "real" world, you'd use data.getUint8, data.getUint16 or even
      // TextDecoder to process raw data bytes.
      for (let i = 0; i < value.byteLength; i++) {
        a.push('0x' + ('00' + value.getUint8(i).toString(16)).slice(-2));
      }
      log('> ' + a.join(' ') + ' (raw data)');
      a.reverse();
      log('> ' + a.join(' ') + ' (bytewise reversed)');
}

function notificationTest(characteristic){

    // 1a. create event handler function for given characteristic
    var characteristicEventHandler = createEventHandler();

    // 1b. register the event handler
    characteristic.addEventListener('characteristicvaluechanged', characteristicEventHandler);

    // 2. start notifications for given characteristic
    startNotification(characteristic);

    // 3a. log data as raw hex values
    //    this is performed in the event handler

    // 3b. log metadata about the characteristic itself
    log('> Testing Characteristic UUID: ' + characteristic.uuid);

    // 4. let some time pass...

    // 5. stop notifications for given characteristic
    stopNotification(characteristic);

    // event handler is destroyed when function is exited
}

function stopAllNotifications(){
    // run over an array containing all characteristics
    allCharacteristics.forEach(function(item, index, array){
        // check if characteristic supports notifications
        if(item.properties.notify){
            item.stopNotifications();
            log("> Stopping notifications for UUID: " + item.uuid);
        }
    })
}

function startAllNotifications(allCharacteristics){
    // run over an array containing all characteristics
    allCharacteristics.forEach(function(item, index, array){
        // check if characteristic supports notifications
        if(item.properties.notify){
            item.startNotifications();
            log("> Starting notifications for UUID: " + item.uuid);
        }
    })
}

function startAllNotificationsWithHandlers(){
    // run over an array containing all characteristics
    allCharacteristics.forEach(function(item, index, array){
        // check if characteristic supports notifications
        if(item.properties.notify){
            notificationTest(item);
            log("> Starting notifications for UUID: " + item.uuid);
        }
    })
}

function addAllCharacteristics(){
    allCharacteristics = [
                deviceNameCharacteristic,
                advertisingParametersCharacteristic,
                appearanceCharacteristic,
                connectionParametersCharacteristic,
                eddystoneUrlCharacteristic,
                cloudTokenCharacteristic,
                temperatureCharacteristic,
                pressureCharacteristic,
                humidityCharacteristic,
                gasCharacteristic,
                colorCharacteristic,
                weatherConfigurationCharacteristic,
                ledCharacteristic,
                buttonCharacteristic,
                motionConfigurationCharacteristic,
                tapCharacteristic,
                orientationCharacteristic,
                quaternionCharacteristic,
                pedometerCharacteristic,
                rawDataCharacteristic,
                eulerCharacteristic,
                rotationMatrixCharacteristic,
                headingCharacteristic,
                gravityVectorCharacteristic
                ];
};

redpajama_set_name: RedPajamaGithub


text:
Q: Не работает редирект на 404-ую страницу для страничек с расширением .php Такой вопрос. На сайте в .htaccess прописано стандартное правило для редиректа с несуществующих страниц на страничку 404.html вида:
ErrorDocument 404 http://mysite.com/404.html
Переадресация работает корректно для всех видов страниц, кроме тех, которые имеют расширение .php.
Т.е., если ввести в браузере  http://mysite.com/noexist.html или http://mysite.com/noexist, то редирект работает как надо, но, если ввести ссылку вида http://mysite.com/noexist.php, то сервер просто выводит надпись "File Not Found".
Подскажите, есть ли возможность как-то настроить это дело в .htaccess?
Вот содержимое файла (заменил название сайта на mysite.com и названия страниц на page.html и page.php):
ErrorDocument 404 http://mysite.com/404.html

Options +FollowSymLinks
RewriteEngine On

RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /index\.(php|html|htm)\ HTTP
RewriteRule ^index\.(php|html|htm)$ http://mysite.com/ [R=301,L]

RewriteCond %{HTTP_HOST} ^www.mysite\.com$ [NC]
RewriteRule ^(.*)$ http://mysite.com/$1 [R=301,L]

RewriteEngine on
RewriteCond %{HTTPS} !=on [NC]
RewriteRule ^.*$ https://%{SERVER_NAME}%{REQUEST_URI} [R,L]

RewriteRule ^main.min.css$ style.min.php [L]
RewriteRule ^main.min.js$ script.min.php [L]

RewriteRule ^index.html /index.php [R=301,L]
RewriteRule ^page1.html /page1.php [R=301,L]
RewriteRule ^page2.html /page2.php [R=301,L]

<FilesMatch "robots.txt$">
RewriteEngine off
</FilesMatch>

## EXPIRES CACHING ##
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text:
La chapelle Notre-Dame-des-Neiges est une chapelle du diocèse de Gap et d'Embrun située à Abriès-Ristolas, dans les Hautes-Alpes.

Histoire et architecture
Attestée dès 1691 par un le chanoine Jacques, la chapelle peut être décrite comme un petit édifice de plan presque carré, construit en soubassement, dont le toit déborde largement au dessus de la façade.

Notes et références

Voir aussi

Articles connexes
 Liste des édifices chrétiens des Hautes-Alpes

Abriès-Ristolas
Abriès-Ristolas
Abriès-Ristolas

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Nine years, 139 startups, $700 million raised.
Techstars Seattle has become a mainstay of the local tech ecosystem for nearly a decade, helping groom early-stage entrepreneurs as they sharpen their pitches and build their business models. Nearly 140 companies have graduated since 2010 and have collectively raised more than $700 million in investment capital. Graduates of Techstars Seattle include companies like Remitly, Outreach, Leanplum and Zipline.
Techstars Seattle Managing Director Chris DeVore.
The latest cohort stepped on stage Wednesday night after three intense months as part of Techstars Seattle, pitching an audience of fellow entrepreneurs, investors, family, friends, and more community members as part of Demo Night at the Museum of History and Industry.
"Thank you to everyone here today for helping make Seattle one of the best places in the world for a startup founder," said Chris Devore, managing director of Techstars Seattle.
Brad Feld, managing director at Boulder, Colo.-based Foundry Group who helped launch Techstars 13 years ago, also spoke on stage Wednesday and credited the Seattle startup community for helping Techstars succeed. The accelerator now funds around 400 startups per year across 40 programs and 12 countries.
"The amount we learned as an organization from being able to work with Seattle as one of our early expansions has been incredible," he said.
This year's Techstars Seattle cohort was its most diverse group yet — three companies led by women, three African-American founders and three teams from Canada. Techstars provides the startups with mentorship, guidance, and a $100,000 investment.
Here's a quick recap of my favorite pitches from Wednesday. You can read more about each company with our Startup Spotlight feature.
"Diversity matters." That's how Stella Ashaolu began her pitch, which was the best of the night. The WeSolv CEO explained how workplace diversity has become a top priority for Fortune 500 companies, yet many are struggling to find and hire high-performing diverse candidates. Her startup is changing the recruiting model, matching companies with MBA students who get a chance to work on projects and build connections with potential employers. There are more than 1,600 MBA students on the platform — 50 percent women; 70 percent from underrepresented groups — and WeSolv has paying customers like Salesforce and Discover. "I know you've seen the headlines," Ashaolu said. "We are at an inflection point. I welcome you to come talk to me about how WeSolv is a timely solution changing hiring." WeSolv certainly faces stiff competition from giants like LinkedIn and Indeed, but its model and timing seem promising.
Educative had the most impressive traction of any company on Wednesday. The company has 10,000 paying customers across 80 countries who are using Educative for software development training. Its marketplace offers interactive and adaptive coding courses, helping developers stay up-to-date with the latest programming frameworks and APIs. "Developers need Educative to learn and get hired," said Educative CEO Fahim ul-Haq, a former Microsoft senior engineer. "Their employers need Educative so that their workforce is up-to-date and productive." The startup bootstrapped its way to $500,000 in revenue last year and now has investor validation — Yuval Neeman, a partner at Trilogy Equity Partners and former Microsoft executive, announced on stage that his firm will be leading Educative's seed round.
Andrew Sampson was calm and confident during his well-paced pitch, clearly explaining the value proposition behind Rainway's gaming service. The Atlanta-based startup has developed technology that lets gamers stream their PC games onto any device, allowing for continued gameplay beyond the confines of a desktop machine. "Mobile devices just can't meet the demands of PC gamers, leaving the entire market underserved or completely left out when PC gamers want to play on the go," Sampson said. Rainway is part of a new trend of technology that goes beyond just gaming and allows people to run a "computer" from any device. The company has racked up 60,000 users in three months and plans to rollout a paid premium version. With an addressable market of 1.2 billion PC gamers, Rainway seems poised for big growth.
Check out the other Techstars Seattle companies below.
Downstream co-founder and CEO Connor Folley.
Halo Automotive CEO Tyler Phillipi.
LaunchBoard CEO Joshua Del Begio.
Spocket CEO Saba Mohebpour was unable to attend Demo Night because of the U.S. travel ban, so he pitched virtually.


text:
Kevin O'Leary (born May 10, 1969, in Blackfriars, London, UK) is a professional poker player of  English descent. A former antiques dealer, he is known on the poker tournament circuit by the nickname "Lovejoy", in reference to the 1980s BBC TV series of the same name, which starred Ian McShane.

Tournaments
O'Leary's poker achievements to date include winning the inaugural GUKPT heads-up championships at London's Grosvenor Victoria Casino, the Caesars Palace Las Vegas "Mega-Stack" championship event in 2008, and making the final table of the televised VC Poker Cup in 2005 at Teddington studios England. He is perhaps best known however, for his prolific tournament record at The Venetian in Las Vegas, where to date he has won a record 5 No-Limit Hold-Em tournaments in the poker room's "Deepstack Extravaganza" series (once in 2007, once in 2008 and three times in 2009), and has also twice won the Venetian's Player of the Series award, again a record in itself. He regularly makes the annual pilgrimage to Las Vegas, where he is a familiar face in Vegas tournaments, including the World Poker Tour, and the World Series of Poker, in which he has also cashed.

O'Leary's biggest single tournament cash to date is $272,000, in the Caesars Palace "Mega-Stack" championship in Las Vegas. He has played most poker variants over the years, but prefers live poker tournaments as opposed to online competitions and cash games, as he feels his edge in live events is much greater, something which appears to be borne out by his record in deepstack freezeout tournaments. A three-year sponsorship deal with UK bookmakers Blue Square ended in 2008 when O'Leary opted to concentrate primarily on live poker rather than play equally live and online.

, his live poker tournament cashes exceed $1,000,000.

Notes

External links
Official Website
UK Pokernews interview
Bluff Europe
Racing Post
GUKPT Bolton final table
Kevin O'Leary Hendon Mob Profile

Poker players from London
Living people
1969 births


text:
Popular Science Monthly/Volume 62/March 1903/The Vienna Academy of Science
Hitherto Unpublished Letters of Charles Darwin
The Vienna Academy of Science by Edward F. Williams
Mental and Moral Heredity in Royalty VIII
1413604Popular Science Monthly Volume 62 March 1903 — The Vienna Academy of Science1903Edward F. Williams
THE VIENNA ACADEMY OF SCIENCE.
By EDWARD F. WILLIAMS,
EARLY in the fifteenth century scholars on the continent of Europe began to discuss questions in little companies out of which grew what are now known as academies of science. At first these societies were made up of thoughtful men who met to compare their ideas on questions and discoveries which were exciting universal interest. The Academia Pontaniana in Naples was organized in 1433; the Academia Platonica in Florence in 1474. The proceedings in these academies were for the most part open to the public, and the work accomplished through them became the means of the formation of the academies of science, which, in most of the capitals of Europe, have filled so prominent a place the past century and have done so much to utilize and spread abroad historical, philosophical and scientific knowledge.
The history and the work of one of these academies, that in Vienna, will, it is believed, be of interest.
A private academy, the Literaria Sodalitas Danubia, started in Ofen in 1490 by Konrad Pickle, a Frenchman known as Celtes, was moved to Vienna in 1497, where it received into its membership philosophers, jurists, doctors of medicine and privy councillors. Its prime object was declared to be to broaden out 'the Humanism' of the time. It continued to prosper while Celtes was its directing spirit, but after his death in 1508 its influence gradually declined.
Early in the eighteenth century Leibnitz was anxious that an academy should be established in the Austrian capital, similar to the one which in 1700 he had persuaded the King of Prussia to organize in Berlin.
The central position of Vienna, the prestige of the Austrian government and the low estate into which universities all over Europe had fallen led him to visit the city and seek aid from those in authority in carrying out his project. Although his plans received favorable attention, wars with the Turks, opposition from Roman Catholics, especially from the Jesuits, and the difficulty of obtaining means for the support of an academy prevented their execution. Still Leibnitz persisted in urging his plans, and on his fifth visit in 1712 began to be confident that the greatly needed academy would soon be organized. His death the following year led to the abandonment of the project for the time. A Leipzig professor, by the name of Gottsched, in 1749 sought to revive the plan of Leibnitz, but although courteously received nothing came from his efforts. He wanted to be a professor in the university and president of the academy, but the fact that he was a protestant undoubtedly stood in his way. Still others than he were interested in the establishment of an academy. A plan presented by Baron von Petrasch in 1746 at the request of Count Haugnitz was laid before the government in 1750 and carefully considered. Under the terms science and the fine arts it proposed to cover the whole field of knowledge. Nothing came of this effort nor of another put forth in 1774, perhaps because the government feared the influence of the union of men so prominent for learning and ability, and perhaps because it did not see whence the means for its support were to come. The project for an Academy was not taken up again in earnest till 1837, when twelve men met in Vienna to talk the matter over. They recognized and emphasized the fact that in most of the large cities on the continent academies had been founded not only to the benefit of their members but to the credit of the cities in which they had their seat. Patriotism, they insisted, required the union of the scholarship of Vienna in an academy as a channel of communication with the learned world. As all who met to discuss the formation of an academy were of one mind as to its necessity, they formulated a plan of work, suggested means for its support and signed a petition to the government for its immediate organization. A small stamp tax on certain articles and the right of the academy to publish a calendar would, they thought, produce the necessary funds. The petition was seriously discussed. Men high in office, of noble birth and near the emperor were in favor of granting the request. The plan now presented was compared with that drawn up in 1750. Public sentiment as represented by the learned class was tested. The professors in the university were asked for their opinion. Some thought there were already too many institutions in the city and that there was neither room nor place for another. The medical faculty as a whole was not in favor of an academy. Some thought its work could not fail to come into conflict with that of the university. But the dean of the faculty of arts, Professor J. J. von Luttrow, wrote that the two could not come into conflict, that a university is a place for imparting knowledge already acquired and tested, while an academy seeks to increase knowledge by investigations and discoveries and furnishes a place where scientific men may compare their theories, criticize them and weigh carefully and judicially the evidence upon which they have been formed. For years the discussions about the forming of an academy continued. The matter was referred, in May, 1838, to a special commission formed by the court. This commission reported favorably in June of the following year. Nothing however was really done till 1847, although several commissions had meanwhile been appointed and without exception had reported that they looked upon the project of an academy with approval. Tired of waiting the movements of the government, a private academy was organized in January, 1846. Its members favored an academy with two classes, historical philosophical, and mathematical scientific, and did their work along these lines. When the petition for the formation of an academy reached the prime minister, Metternich, he simply said that it was unnecessary as he had long since determined to found an academy and had secured a plan for it. From its discussions he proposed to exclude theology, literature, politics and ethics, and limit them to the subjects connected with positive science. In presenting his plan to the emperor, which received his approval, the minister said that the conservatism of the academy would counteract prevailing disturbances in thought, especially in politics, and furnish a center around which monarchical ideas would crystallize. It was decided that a prince of the reigning house should be curator, that the president should be a nobleman, that there should be 48 active members, as many corresponding members, and one public meeting a year; that the cost should be borne by the government, but must be limited to 40,000 gulden annually; that for each of the two classes a secretary should be chosen, to whom, with the dean and the president, small salaries should be paid, but that ordinary members should receive nothing, inasmuch as many of them, professors in the university and in other offices, were already in the service of the government. Final and favorable action was taken in November, 1847, though the formation of the academy had been officially announced in May of that year. The Academy consisted of 40 active members, 18 of them resident in Vienna, the others representing various sections of the realm. Many reasons prevented the curator, Archduke John, from issuing a call for the meeting of the academy till February, 1848. It had been agreed that in addition to the forty members named by the emperor out of the lists furnished him, these forty should have the privilege of choosing eight more members and, subject to the emperor's approval, of electing its president, its secretaries and its dean. The cost of printing the papers presented to the academy was to be met by the government, but to the request that these papers be free from police supervision a negative answer was returned. This was in the revolutionary year 1848. The day after the request for freedom of publication had been denied a mob gathered in Vienna, the emperor surrendered his absolute power and granted the academy the liberty it desired. He also permitted the academy to increase its membership, by 12 in each class, and to elect an equal number of corresponding members. Though providing amply for the study of history and philosophy, the first place was given to science. Hammer Purgstall was chosen the first president. "An academy," said he, "is a union of spiritual forces for the advance of knowledge in its highest development and power. It does not busy itself with the instruction of youth but with protecting and stimulating men of learning. It is a sort of judgment seat to which scientific attainments are brought and at which their real value is appraised."
Though hesitating so long over the establishment of an academy, having permitted its organization, the government did not fail to favor it in every possible way and to provide handsomely for its support. Rooms were set aside for its sessions and its work, in the Polytechnic Institute. Since 1857, it has had a home of its own in a building long used as barracks for soldiers, but designed, according to tradition, by the Empress Maria Theresa for the academy which she herself intended to found. Here the general secretary resides, and as the building is very large, several scientific societies have courteously been granted shelter. The correspondence of the members of the academy within the realm goes free. Save in the summer months, sessions are held every week and, with the exception of a single meeting each month, the different sections of the academy meet by themselves. The proceedings of the meetings fill many volumes and form a collection of scientific, historical, philosophical and archeological papers of almost inestimable value. Twenty-four active members now reside in Vienna. Strangers properly introduced are permitted to attend the sessions of the academy, though none of these sessions are open to women.
The means at the disposal of the academy, though they cannot be given with absolute accuracy, are for an institution of the kind quite large. They make it clear that its members have the confidence of the public and that the work they are doing appeals to men of wealth and lovers of learning. From the sale of an almanac which contains brief reports of the proceedings of the academy the profits are not inconsiderable. Extraordinary grants from the government and gifts from rich men have from time to time been made for special purposes. That infirm officers of the academy may receive pensions, since 1898 the government has given 50,000 gulden annually, instead of the 40,000 previously received. To this sum are added 20,000 gulden for printing, and 7,000 gulden to each class for pressing needs. Property left to the academy for prizes, or to be used in any way which in the judgment of its members will increase knowledge and promote its diffusion, now produces a large income. Since 1890, Prince John of Lichtenstein has given 5,000 gulden annually for excavations in Asia Minor, and since 1900 has doubled the amount.
Experience has convinced the academy that the giving of prizes is not the best way to use money. Only such are awarded as are made necessary by the terms of a bequest. The offer of prizes, it is affirmed, only stimulates a man who has work in hand to complete it, but rarely induces one to begin new work or to enter upon investigations which may result in important discoveries and valuable additions to human knowledge. So far as possible the income of the academy, which is now between forty and fifty thousand dollars a year from its own funds, is employed in subventions, to aid in printing important treatises, for travel, for excavations or special work. A brief reference to what has been accomplished will justify the demands of the friends of the academy for its establishment. It has provided for the publication of the 'Corpus Scriptorum Ecclesiasticarum Rerum' in many volumes and of many volumes of reports of the excavations of the prehistoric commission for whose work it furnished the means. It has nearly completed the petrographic study of the central chain of the Eastern Alps, and has made a map of the region. In 1894 it joined in an international enterprise to discover the weight of the earth. In 1897 it sent, at a cost of more than 20,000 gulden, an expedition to Bombay to study the bubonic plague. Its bacillus was discovered, but the young man in charge of the expedition lost his life. In 1898 and 1899, it had a commission at work in southern Arabia, and on the island of Socotra. In 1897 it completed deep sea soundings in the Mediterranean, especially in what is called the Adriatic Sea. In 1899 it sent a double expedition to India to study meteors and the eclipse and in 1891 it sent a botanic expedition to Brazil. The results of all these expeditions and of others almost as important have been carefully edited and given to the world through the press.
In 1901 36 annual 'advertisers' had appeared and 49 'almanacs.' These were filled with information not elsewhere to be obtained. At that time the philosophical class had published 48 volumes of works prepared under its direction and 141 volumes of 'Proceedings.' The scientific class had published 68 volumes of special treatises and 108 volumes of 'Proceedings.' Five parts of the 'Report of the Prehistoric Commission' had also appeared. For twenty years and more monthly reports of the condition of chemistry in Europe and throughout the world have been printed and circulated. Of the 'Archives for Austrian History' 88 volumes have appeared, of the 'Sources (Fontes) for Austrian Affairs,' 8 volumes in the First Part, 51 in the Second Part; of 'Announcements from the National Archives,' 2 volumes, of the 'Monumenta Concilliorum,' 2 volumes, and 4 volumes of Part III. Of the 'Hapsburg Memorials,' divisions two and three of Vol. I. have been printed and one part of Vol. II. Ten volumes of the 'Tables of Codices' have appeared, three of the 'Venetian Dispatches' and the second division of Vol. II.
The Academy claims to have suggested and obtained the appointment of a committee to consider the sources of Indian lexicography; to investigate the condition of the Corpus Scriptorum of Oriental knowledge; to look after Grecian grave inscriptions and to create a commission for the study of oceanography. It shares with the Berlin Academy and with the academies of Munich, Göttingen and Leipzig in the preparation of a Latin dictionary. The work is done in Munich and on a scale which may require twenty years to complete. Together with the academies of Munich, Göttingen and Leipzig, it has carried through and nearly completed an 'Encyclopedia of Mathematics and Related Knowledge,' and has agreed to join with them in the future in any work which ought to be undertaken, but which is too large for the resources of a single academy. It joined the international association of academies in 1900, and is taking part in the publication of the international catalogue of scientific literature. Statements by the secretary of what was done during the year 1899-1900 show the great place the academy now fills. The Prehistoric Commission, he says, continued its investigations at Töplitz near Krain, and discovered in graves which had never been opened many articles belonging to a prehistoric race. The work is nearly complete and full reports of it will soon be published. Successful efforts have been made to obtain a complete collection of objects needed for the 'Phonographic Archives' of the academy. The third part has been published of the report of the Austrian Plague Commission on the morphology and biology of the bacillus, and on the means to be used for the disinfection of man and beast and their future protection against danger from this source. A report of the visit to India to photograph meteors and observe the eclipse has been printed. Opportunity was taken during this visit to secure measurements of the intensity of the sun's heat and to collect twenty specimens of orchids. The petrographic survey of the Alps has been continued and provision made for publishing part A of Vol. VI. of the 'Mathematical Encyclopedia.' The material is in hand for nearly all the work. The Earthquake Commission has made observations in Istria and Dalmatia, in Krain and Görz. The number of earthquakes studied is 190, in the previous year 209. Reports from several hundred meteorological stations have been received and tabulated for use not only in the study of meteorology but for the study of terrestrial magnetism.
Under the patronage of the 'historical class' of the academy important publications have been brought out on the early history of Austria-Hungary. Some new historical facts have been discovered during the year. Work on the edition of the Latin church fathers has continued, and the writings of Arnobius Minor have been worked over by J. Schnarnagl, those of Cæsar Arelatorius by G. Morris, those of Prudentius by J. Bergmann. It is hoped to get these writings into such shape as to make them valuable. The collection of manuscripts belonging to the library, through the aid of other libraries and by purchase, has been greatly increased. As the result of an archeological journey to Permesos in Pisidia nine graves, differing in type from any yet opened, were carefully examined. Vol. I. of this report has now been published.
The Academy is trying to obtain for its 'Phonographic Archives': (1) Exact representations of the sounds of European languages and dialects at the beginning of the twentieth century, (2) representations of the best musical accomplishments of the present time and of the musical productions of peoples of different degrees of culture as a basis for comparison, (3) representations of the tones of the voices of distinguished men. These tones the phonograph will preserve. The results of the expedition to southern Arabia and Socotra will soon appear in a large number of volumes, giving an account of reptiles, fishes, insects, lepidoptera, diptera, coleoptera, neuroptera, etc. The gains for linguistics and epigraphy are said to be very great.
The study of the results of the commission to India to gather information in regard to the cause of the bubonic plague has discovered its bacillus and made it possible to prevent the spread of the plague in the future. An essay on 'Die Porcia von Socotra,' published by the academy, has pointed out the possible relation of this Porcia to the Portia of Shakespeare. Several tales current among the people of Socotra and on the coast were carefully written down and will not only show how stories of this character travel from country to country, but will add to our knowledge of folk-lore. Work which promises to be of importance has been done in the study of the syntax and philology of the Slavic languages, and several publications have appeared on the political history and philosophy of the Slavic peoples. The Academy is attempting to investigate and study accurately the history, archeology, philology and ethnology of the entire Balkan peninsula.
The archeological work of the academy proved to be of such importance and extent that a special society was formed to carry it forward. Explorations in Ephesus were made in 1897, preliminary reports of which have appeared, and also of work done in Cilicia. In the spring of 1898 measurements were made in Luxor, Egypt, to determine the influence of winter climate on atmospheric electricity, in Siberia to discover the influence of extreme cold, and in a balloon at the height of 4,000 meters. The Academy has taken part with the German academies in preparing an Encyclopedia of Mohammedanism and it shares with the academies of Berlin and Munich the income of the Savigny bequest for the study of Law, German and Roman, and the law of all nations. The subventions, which cover almost every department of scientific research, and those made for historical and philosophical purposes, over fifty in number, now exceed in amount 75,000 florins annually. They indicate an activity in research equaled by no other academy save that of Berlin on the continent and are producing results in which the members of the academy may justly take great pride.
In closing this brief account of what a single academy of science on the continent of Europe has done, it may not be out of place to add that, as the work of the academy has expanded, other societies, chiefly scientific or archeological, have grown out of it, thus proving it to be, as was predicted long before its formation that it would be, the mother of scientific and historical learning in Austria. The academy in Buda Pesth has larger resources of its own than the Vienna Academy and has pushed its work with untiring zeal. Barriers of language render the results of its work less accessible than those of the German academies. Two academies in Prague, one for the Germans of the city and of Bohemia, and one for the Czechs, both under the protection of the government and in receipt of grants from it year by year, have done excellent work, but on a smaller scale than at Vienna. Of lesser academies in various cities in the empire, or of learned societies it is unnecessary to speak, inasmuch as the Vienna Academy is the model which, so far as possible, all of them try to follow.
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Scientific societies articles in Popular Science Monthly


Long Division is Wakefield's largest annual music and culture festival. It was created in 2011 and has taken place in 25 different venues across the city centre since then. It has brought large internationally touring artists such as British Sea Power, The Fall, Ash, Field Music, Ghostpoet and The Cribs (their only public hometown show on over ten years) to Wakefield and programmed them alongside emerging local talent. It has also used funding to develop Fringe events, including Live Album Recordings, workshops and industry Q&As and has also run Outreach events across the district.
Join us on June 10th for our Alternative Wakefield event.