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Op-Ed: US seeks a political deal in Libya with a large role for Haftar
By Ken Hanly Apr 11, 2019 in Politics
Apparently the United States is pushing Haftar for a bigger role in official Libyan affairs but does not want him to continue his campaign attacking the Libyan capital Tripoli.
US wants political solution but with large role for Haftar
An anonymous former US official recently told Al Monitor: "The US doesn't want Hifter to continue with this campaign. I think they'd like to see him in a powerful position within the security apparatus of a unified Libyan state, but they want him to be incorporated into the state via a political solution to the conflict."
Haftar has always preferred a military solution and has threatened to "liberate" Tripoli several times and has often sabotaged UN peace efforts and refused to accept the 2015 Skhirat agreement or the authority of the Government of National Accord (GNA) recognized by the UN and most countries as the legitimate government of LIbya. However, recently Haftar and the GNA Prime Minister Serraj met and agreed that national elections are necessary.
Now that Haftar is attacking Tripoli Serraj, who has in the past not been critical of Haftar and tried often to negotiate with him, has finally spoken out against him. Several times Haftar has refused to meet with Serraj. A recent article notes that Sarraj, the Prime Minister of the Government of National Accord accused Haftar by name as violating political agreements concluded under the auspices of the United Nations saying: "We have stretched out the hand of peace, but the aggression of Haftar's forces and declaration of war against our cities and our capital, and therefore violation of political agreements by him, will only make us resolute and give us strength."
US still hoping for a political solution
A recent article claims: "Libyan National Army (LNA) head Khalifa Hafter, who is in the process of attacking the capital city of Tripoli for at least the third time since 2014, is reportedly being pushed by the US government for a bigger role in official Libyan affairs. This could include making him the head of the actual Libyan military, instead of just the one he pieced together himself."
There are many especially in western Libya who would never accept Haftar as head of the national army. It is unlikely that Haftar would accept the post either if he were under civilian rule unless he controlled the civilian government.
Haftar promotes himself as a military strongman to promote stability
Haftar has a long history in Libya being part of the 1969 Gadaffi coup. However he was captured in a disastrous campaign in Chad and ended up being saved by the CIA. While in the USA, he worked with rebel groups as he hated Gadaffi who had abandoned him and his men in the Chad war. He was part of a CIA-funded rebel force in the 1980s. Haftar is an American citizen.
Gadaffi was ousted in 2011. In 2014 Haftar attacked parliament and in effect launched a coup of his own. He began his Operation Dignity designed to rid Libya of those he called terrorists. In 2015 the eastern government of the House of Representatives appointed him as head of the so-called Libyan National Army (LNA) although it is not the army of the recognized Libyan government. Haftar got the new title of "field marshal". LNA forces have gradually expanded the territory controlled by Haftar and the eastern government. He has consolidated his power controlling many of the oil ports and fields. In spite of the fact that he would have considerable power under the political agreement with Serraj he has chosen his preferred military solution.
UN's planned conciliation talks sabotaged by Haftar
Haftar's attack on Tripoli sabotaged the planned UN conciliation talks. As he has done many times, Haftar has chosen a miitary solution while sabotaging a political one.. At one time, the EU even considered sanctioning him. As a 2015 July Reuters article notes: "Two military leaders in the east of Libya, who say their forces will not respect any peace accord, also face sanctions. They are General Khalifa Haftar, commander in chief of the eastern forces and air force head Fakir Jarroushi." Of course nothing happened.
With Tripoli under attack no one wants to hold talks except perhaps on a ceasefire. However, the US sees the solution as promoting Haftar to be head of the national Libyan armed forces. They may think that Haftar will not attack Tripoli if he is part of the government that controls it. However, given Haftar's bold military move, the US has not represented itself as clearly aligned with Haftar and as with Russia also claims to support the GNA. Both countries have shown support for Haftar but France, outside of Egypt and the UAE, has been the most outspoken in support creating some conflict with Italy.
The result of Haftar's attack is not clear yet but he appears to be facing more resistance than he had counted on. If he is defeated it will be interesting to see what the reaction of his supporters, the US, Russia, France, Egypt, and the UAE will be. Libya could be in for an extended period of clashes, the last thing the country needs.
This opinion article was written by an independent writer. The opinions and views expressed herein are those of the author and are not necessarily intended to reflect those of DigitalJournal.com
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Khalifa Haftar Libya US in Libya


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Smith says Archer blow brought back difficult memories
Published Wednesday, August 28, 2019
Australia talisman Steve Smith has said he will change nothing in his approach to facing Jofra Archer after being hit by a short ball from England's tearaway paceman but admitted the blow had revived troubling memories of Phillip Hughes.
Smith's former Australia team mate Hughes died after being struck with a bouncer during a Sheffield Shield match in Sydney in 2014, shining the spotlight on the dangers of short-pitched bowling.
Smith was floored by a short Archer ball in the second test at Lord's, and although he returned to bat again after a concussion test, he was later ruled out of the third match at Headingley, which England won in a cliffhanger by one wicket.
The former captain said his mind was racing after the immediate impact of the blow from Archer's delivery.
"I had a few things running through my mind, particularly where I got hit," Smith told reporters.
"Like a bit of the past sort of came up, if you know what I mean, from a few years ago. That was probably the first thing I thought about.
"Then I thought, 'I'm actually OK here'. I was a bit sad, but I was alright mentally for the rest of that afternoon."
With Australia's best batsman sidelined at Headingley, all-rounder Ben Stokes scored a magnificent unbeaten century to carry Joe Root's England to victory and level the five-match series at 1-1 ahead of the fourth test at Old Trafford next week.
Smith did not relish being a spectator at Headingley but said he expected to be back in the thick of it in Manchester.
He dismissed the idea that Archer might have an edge against him should they face off again.
"No, I'm not really going to change anything. There's been a bit of talk that he's got the wood over me but he hasn't got me out," said Smith of England's tearaway paceman.
"He hit me on the head on a wicket that was a bit up and down at Lord's.
"All the other bowlers have had more success against me, I dare say. I've faced them a bit more but they've all got me out a lot more, so, yeah, pretty comfortable about that."
Smith sounded equally comfortable with the prospect of an even heavier short ball barrage at Old Trafford.
"If you bowl it up there it means they can't nick me off or hit me on the pad or hit the stumps," he shrugged.
"With the Dukes ball, I don't know - it's an interesting ploy, so we'll see what happens."
Governing body Cricket Australia is looking to make neck guards compulsory on helmets within a year to give batsmen more protection.
Smith said he had tried them out and his heart-rate had gone up about "30 or 40" beats per minute.
"I just feel claustrophobic. I compare it to being stuck in an MRI scan machine so it was different," he said.
"At some point they're probably going to become mandatory so I am going to have to get used to them."

redpajama_set_name: RedPajamaCommonCrawl


Mary, don't hesitate to use 'The Wild Geese in NYC' group's e-mail broadcasting capability to share the news of all your performances. Doing so is a service to us all. I believe you have joined that group, along with dozens of others.


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Nandan Mehta (26 February 1942 – 26 March 2010) was an Indian tabla player and music teacher from Ahmedabad who belonged to the Benaras Gharana of Hindustani classical music. He established Saptak School of Music and started Saptak Annual Festival of Music in 1980.

Early life
Nandan Mehta was born on 26 February 1942 to Yashodhar Mehta, a writer and lawyer, and Vasumati, a painter and daughter of Sir Chinubhai Baronet. His grandfather Narmadashanker Mehta was a reputed Vedanta scholar.

He was trained under Kishan Maharaj and was a tabla exponent of the Banaras Gharana. He introduced Banaras Gharana to Gujarat.

Musical career
He was a Senior A Grade artist of All India Radio and Doordarshan. His performances won him acclaim. He performed extensively across the country and participated in the AIR National Programmes as well as the Akashvani Sangeet Sammelan. He also served to AIR on their Staff Selection Committee, Ahmedabad and also served on their Music Audition Board.

He established Saptak School of Music and started Saptak Annual Festival of Music in 1980.

Death
Nandan Mehta succumbed to oral cancer on 26 March 2010. His wife, Manju Mehta is a sitar player and his two daughters, Poorvi Mehta, a sitar player and Hetal Mehta, a tabla player.

The gallery dedicated to his life and the Saptak Annual Festival of Music was opened in Ahmedabad in 2012.

Recognition
He was honoured by Pandit Jasraj twice (1997 and 2002) on behalf of the Mewati Gharana and was conferred the title of 'Tal Rasik Var'. "Sankalp" central body at Kurukshetra conferred on him the title of 'Sangeet Rushi' in the year 1996. Kumar Club Shastriya Group Ahmedabad also honoured him for rendering outstanding services to the field of classical music. He has been awarded the prestigious 'Gaurav Puraskar' by the Gujarat Sangeet Natak Academy for his outstanding contribution in the field of music in the year 1988.  He was also honoured on 'Vishwa Rang – Bhoomi day' for his contribution in the field of music in Vadodara, and by the Medical Association in Ahmedabad. Swar Sadhana Samiti, Mumbai, awarded him 'Swar Sadhana Ratna' in the year 2004. He was also honoured by 'Kala Gurjari' Bhavnagar, Sangeet Kala Niketan, Jaipur. He was also honored by Madhuvan, Bhopal for his contribution in the field of music in the year 2005. He was conferred the title 'Shreshth kala Acharya'. Dr.H.L.Trivedi, Director, Kidney Institute has also honoured him for rendering outstanding services in the field of Classical music and conferred the title 'Bhagwan Mahavir Karuna Sewa Sanman' in 2007. He was awarded "Sangeet Ratna Chudamani" by Divya Jivan Sangh Shivanand Ashram Ahmedabad  in 2008 by Naval Kishore Sharma, Governor of Gujarat.

He was awarded Sangeet Natak Akademi Award in 2007.

References

External links
 Saptak

1942 births
2010 deaths
Musicians from Ahmedabad
Tabla players
Recipients of the Sangeet Natak Akademi Award
20th-century Indian male classical singers

redpajama_set_name: RedPajamaWikipedia


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\section{Introduction}
\label{sec:introduction}
It is currently still unknown how much reprocessing of material occurs during the collapse from a prestellar core to a protostar and disk. Two scenarios can be considered: the inheritance scenario where the chemical composition is conserved from cloud to disk, or the (partial) reset scenario where the envelope material is modified during its trajectory from envelope to disk. Some inheritance is suggested by the rough similarity between cometary and interstellar ices \citep{Mumma2011,Drozdovskaya2018,Drozdovskaya2019}. On the other hand, some modification of envelope material is expected due to the increase of temperature and stellar ultraviolet (UV) radiation during infall \citep[e.g.,][]{Aikawa1999,Visser2009}. Moreover, as the infalling envelope hits the disk, an accretion shock may develop which will alter the composition of the material flowing into the disk, and therefore (partially) reset the chemistry. In the most extreme case, reset implies complete vaporization of all molecules back to atoms with subsequent reformation. Milder versions of reset include sputtering of ices, and gas and ice chemistry modifying abundances.

Already in the earliest Class~0 phase of the low-mass star-formation process, an accretion disk around the young protostar is formed \citep[e.g.,][]{Tobin2012,Murillo2013}. The impact of infalling envelope material onto the disk can cause a shock, raising temperatures of gas and dust at the disk-envelope interface to values much higher than from heating by stellar photons alone \citep{Draine1983,Neufeld1994}. These low-velocity ($\sim$ few km~s$^{-1}$) accretion shocks at high densities ($\sim10^7$~cm$^{-3}$) are widely found in models and simulations \citep[e.g.,][]{Cassen1981,Li2013,Miura2017}, and often invoked in Solar System formation to explain phenomena like noble gas trapping \citep{Owen1992}. They are most powerful in the earliest stages when the disk is still small ($\lesssim 10$~AU). However, that infalling material may eventually end up in the protostar and not in the disk. As the embedded disk reaches a size of (several) tens of AU, the envelope material entering the disk will remain there and eventually form the building blocks of planets \citep[e.g.,][]{Harsono2018,Manara2018,Tychoniec2020}.

These accretion shocks have not yet been undisputedly detected. Typical optical shock tracers such as [O\,{\sc i}]~$6300~\AA$ and [S\,{\sc ii}]~$6371~\AA$ are more sensitive to high-velocity shocks \citep[\mbox{$\gtrsim20$~km~s$^{-1}$}, e.g.,][]{Podio2011,Banzatti2019} and difficult to detect in protostellar environments due to the high extinction by the surrounding envelope. Observations of mid-infrared (MIR) shock tracers such as H$_2$O, high-J CO, [S\,{\sc i}]~$25~\mu$m, and [O\,{\sc i}]~$63~\mu$m suffer from outflow contamination in low-spatial resolution space-based observations \citep[e.g.,][]{Kristensen2012,Nisini2015,Riviere-Marichalar2016} and from the Earth's atmosphere for ground-based observations; here the launch of the {\it James Webb} Space Telescope (JWST) will provide a solution. At sub-mm wavelengths, classical diagnostics of shocks include sputtering or grain-destruction products such as CH$_3$OH and SiO \citep[e.g.,][]{Caselli1997,Schilke1997,Gusdorf2008_1,Gusdorf2008_2,Guillet2009,Suutarinen2014}. However, usually these species are only observed in relatively high-velocity outflows and jets through broad emission lines \citep[e.g.,][]{Tychoniec2019,Taquet2020,Codella2020}.

Sulfur bearing species such as SO and SO$_2$ have been suggested as possible accretion shock tracers. An enhancement of warm SO emission at the centrifugal barrier, the interface between envelope and disk, has been observed in the L1527 Class~0/I system with the Atacama Large Millimeter/submillimeter Array (ALMA) at $\sim100$~AU scales \citep{Sakai2014,Sakai2017}. A similar rotating structure in SO has been seen toward the Class~I system Elias~29 \citep{Oya2019}. Equivalently, warm SO$_2$ emission possibly related to an accretion shock was observed toward the B335 Class~0 protostar \citep{Bjerkeli2019} and a few Class~I sources \citep{Oya2019,Elizabeth2019}. However, both SO and SO$_2$ are also seen related to outflow activity, both in large-scale outflows \citep[e.g.,][]{Codella2014,Taquet2020} as in disk winds on smaller scales \citep[e.g.,][]{Tabone2017,Lee2018}.
Moreover, high-angular resolution observations ($\sim30$~AU) of the Class~I source TMC1A show narrow SO emission lines coming from a ring-shaped morphology which may be linked to the warm inner envelope \citep{Harsono2021}. Emission from warm SO and SO$_2$ is thus not an unambiguous tracer of accretion shocks; comparison to shock models is necessary to make robust conclusions.

In shocks, the gas temperature readily rises to $>100$~K \citep{Draine1983,Flower2003,Godard2019}, enough to ignite gas-phase formation of SO and SO$_2$ \citep[e.g.,][]{Prasad1980,Hartquist1980}. A key species for this is the OH radical, which is efficiently produced in shocks through the endothermic reaction between H$_2$ and atomic oxygen, but also through photodissociation of H$_2$O. The OH radical reacts with atomic sulfur to form SO and subsequently to form SO$_2$.
Moreover, SO can also be formed from the SH radical reaction with atomic oxygen \citep{Hartquist1980}. Since the gas-phase chemistry of SO and SO$_2$ in shocks is dependent on radicals such as OH and SH, the abundance of these species is not solely determined through the temperature in the shock but also through the strength of the local UV field.

Alternatively, thermal desorption of SO and SO$_2$ ice in shocks can enhance the gas-phase abundances of SO and SO$_2$.
In interstellar ices, OCS is the only securely identified sulfur-bearing species \citep{Geballe1985,Palumbo1995}, with a tentative detection for SO$_2$ \citep{Boogert1997,Zasowski2009}. H$_2$S is suggested as the main sulfur carrier in the ices \citep[e.g.,][]{Vidal2017}, but so far only upper limits could be derived \citep{Jimenez-Escobar2011}. To date, SO ice has not yet been detected. All aforementioned species are observed in cometary ices such as 67P/Churyumov–Gerasimenko \citep{Calmonte2016,Rubin2019,Altwegg2019}.
\citet{Miura2017} modeled low-velocity (2~km~s$^{-1}$) accretion shocks taking into account the dust dynamics but without any gas-phase chemistry included and could only explain the observations of \citet{Sakai2014} if SO was thermally desorbed while adopting dust grains that were smaller than 0.1~$\mu$m. Sputtering seems to be irrelevant as this becomes only efficient at larger shock velocities \citep[$>10$~km~s$^{-1}$; e.g.,][]{Aota2015}.
However, to thermally desorb sulfur-bearing ices such as SO and SO$_2$ from the grains, the dust temperature has to reach values on the order of 40--70~K.

In this paper, we present a grid of irradiated low-velocity ($<10$~km~s$^{-1}$) $J$-type accretion shock models at typical inner envelope densities ($10^{5}-10^{8}$~cm$^{-3}$). This is a different parameter space than usually explored in, for example, higher-velocity ($>10$~km~s$^{-1}$) outflows at lower densities ($\sim10^4$~cm$^{-3}$).
The goal is to test under what shock conditions the abundance of warm SO and SO$_2$ is significantly increased.
In Sect.~\ref{sec:model}, the model and input parameters are introduced. We present the results of our analysis in Sect.~\ref{sec:results}, after which we discuss these results in Sect.~\ref{sec:discussion}. Our conclusions are summarized in Sect.~\ref{sec:summary}.

\section{Accretion shock model}
\label{sec:model}

\subsection{Shock model}
\label{subsec:model}
The accretion shock at the disk-envelope interface is modeled using a slightly modified version of the Paris-Durham shock code \citep{Flower2003,Lesaffre2013,Godard2019}. This publicly available numerical tool\footnote{\url{https://ism.obspm.fr}} computes the dynamical, thermal, and chemical structure of stationary plane parallel shock waves. The models therefore represent a continuous inflow of envelope material onto the disk and thus a continuous sequence of shocks. The location of the accretion shock is expected to move outward as the disk grows and evolves \citep{Visser2010}.

In this paper, only stationary non-magnetized $J$-type accretion shocks are presented. The presence of a magnetic field could result in $C$ or $CJ$-type shocks \citep[e.g.,][]{Draine1980,Flower2003}, see Appendix~\ref{app:mag_shock} for details. However, the length of $C$-type accretion shocks is strongly dependent on the initial conditions and the size of dust grains and may reach envelope scales of $\sim1000$~AU, which is not consistent with the emission of SO and SO$_2$ seen on $<100$~AU scales \citep[e.g.,][]{Sakai2014,Sakai2017,Elizabeth2019,Oya2019}. $CJ$-type shocks could be relevant in intermediate magnetized inner envelopes \citep[$\sim0.1$~mG;][Appendix~\ref{app:mag_shock}]{Hull2017}, but to compute $CJ$-type shocks across our specific parameter space (low velocities, high densities), the Paris-Durham code needs to be tuned, which is beyond the scope of this work. Nevertheless, the results of $CJ$ and $C$ type shocks are not expected to be different from $J$-type shocks in terms of chemistry.

In the following sections, the main physical and chemical quantities and properties that are included in the model are introduced. In particular, the most relevant physical and chemical processes and updates on the version of the code presented by \citet{Godard2019} are highlighted.

\subsubsection{Geometry}
\label{subsubsec:geometry}
The shock is calculated following a stationary plane parallel structure, see Fig.~\ref{fig:physical_structure}. A shock front propagates with a velocity $V_\mathrm{s}$\ in the direction of negative distance $z$.
The entire structure is irradiated with an isotropic radiation field equal to the isotropic standard interstellar radiation field (ISRF) scaled with a factor $G_0$\ \citep{Mathis1983}, as was implemented by \citet{Godard2019}.
In protostellar systems, the UV radiation can originate both from the accretion onto the protostar itself or from shocks in the bipolar jets \citep[e.g.,][]{vanKempen2009,Yildiz2012,Benz2016}. Moreover, the extinction $A_\mathrm{V}$ between the source of UV irradiation and the shock at the disk-envelope interface can be as high as $\sim10$~mag \citep[e.g.,][]{Drozdovskaya2015} and is assumed to be taken into account with the choice of $G_0$.
Therefore, the exact source of UV radiation is irrelevant here as long as a reasonable range in $G_0$ is covered and since the radiation field is assumed to be isotropic.
A diluted black body of 100~K representing far-infrared (FIR) dust emission from the accretion disk is added to the radiation field. Assuming an emitting region of $4.5$~AU at a distance of $100~$AU, the black body is diluted with a factor $W=5\times10^{-4}$ \citep[for details, see Appendix~A of][]{Tabone2020}, and is constant for all models. Additionally, secondary UV photons created through the collisional excitation of H$_2$ by electrons produced by cosmic ray ionization are included.

\begin{figure}
\includegraphics[width=1.0\linewidth]{{source_structure_J_v3}.pdf}
\caption{Physical structure of a protostellar envelope.
Starting with dark cloud conditions,
an accretion shock model is calculated. The shock profile in the bottom panel is shown on a logarithmic scale, with the yellow region indicating the shocked region.}
\label{fig:physical_structure}
\end{figure}

\subsubsection{Radiative transfer and photon processes}
Photodissociation and photoionization processes of both the gas and dust are taken into account. The cross sections are taken from the Leiden database \citep{Heays2017}. To save computation time, the photoreaction cross sections were only used for the photodissociation of CH, CH$_3$, CH$_4$, NH, CN, O$_2$, OH, H$_2$O, H$_2$CO, SH, H$_2$S, CS, OCS, SO, and SO$_2$, and the photoionization of C, S, CH, CH$_3$, CH$_4$, O$_2$, OH, H$_2$O, H$_2$CO, SH, H$_2$S, and SO. Photodissociation and photoionization of all other species are also included in the chemistry, but using the analytical expression of \citet{Heays2017}. Due to the self-shielding properties of H$_2$, CO, and N$_2$, photodissociation of these species is assumed to be negligible. The destruction of atoms and molecules by far-ultraviolet photons between $911~\AA$ and $2400~\AA$ are calculated including both continuum and discrete processes.

\subsubsection{Grains and PAHs}
The grains are assumed to have grown in protostellar envelopes to larger sizes than the typical interstellar medium (ISM) distribution \citep[e.g.,][]{Guillet2007,Miotello2014,Harsono2018,Galametz2019}. Here, we assume that all grains have an initial core size of $0.2~\mu$m \citep{Guillet2020}, and are either neutral, or single negatively or positively charged. Moreover, the dust grains are assumed to be dynamically coupled to the gas.
Grain-grain interactions are not included since vaporization and shattering of dust grains are only relevant for $J$-type shocks moving at high velocities \citep[$> 20$~km~s$^{-1}$;][]{Guillet2009}. Dust coagulation could potentially be relevant in changing the grain size distribution \citep{Guillet2011,Guillet2020}, but is not included here.

Other large species are polycyclic aromatic hydrocarbons (PAHs), which are modeled here as single particles with a size of $6.4~\AA$ \citep{Flower2003}. In most studies of interstellar shocks, the abundance of PAHs is set to the typical value of the ISM \citep[$\sim10^{-6}$ with respect to the proton density $n_\mathrm{H} = 2n(\mathrm{H}_2) + n(\mathrm{H}) + n(\mathrm{H}^+)$;][]{Draine2007}. However, given that PAHs freeze out in dense clouds, the abundance of PAHs in the gas is set to $\sim10^{-8}$ with respect to $n_\mathrm{H}$\ \citep{Geers2009}.

\subsubsection{Chemical network}
The chemical network adopted in this work consists of 143 species which can take place in about a thousand reactions, both in the gas phase and in the solid state. The network is largely similar to that used by \citet{Flower2015} and \citet{Godard2019}, with the addition of important sulfur bearing ices such as SO and SO$_2$ and their desorption and adsorption reactions. Moreover, the binding energies of all ice species were updated \citep[e.g., 1800~K, 3010~K, and 2290~K for SO, SO$_2$, and H$_2$S, respectively;][]{Penteado2017}. For a density of $10^8$~cm$^{-3}$, this results in a sublimation temperature of 37~K, 62~K, and 47~K for SO, SO$_2$, and H$_2$S, respectively. For simplicity, grain surface reactions have been disabled since the effect of these reactions on timescales of the shock is negligible.
Sputtering of ices is not relevant here since in $J$-type shocks all material is coupled in one fluid.

\subsubsection{Heating and cooling}
The thermal balance is calculated consistently throughout the shock. The main sources of gas heating in non-magnetized $J$-type shocks are through viscous stresses and compression of the medium at the shock front where $T_\mathrm{gas}$ increases adiabatically over a few mean free paths. A second form of heating occurs through irradiation coming from the incident local UV radiation field and through gas-dust thermal coupling.

The gas is cooled through atomic lines of C, N, O, S, and Si, ionic lines of C$^+$, N$^+$, O$^+$, S$^+$, and Si$^+$, and rotational and rovibrational lines of H$_2$, OH, H$_2$O, NH$_3$, $^{12}$CO, and $^{13}$CO \citep{Flower2003,Lesaffre2013,Godard2019}. All cooling by atomic and ionic lines, as well as rovibrational lines of H$_2$ are calculated in the optically thin limit. The cooling of OH is calculated using an analytical cooling function \citep{Lebourlot2002}, which holds up to densities of $10^{10}$~cm$^{-3}$. However, for NH$_3$, local thermodynamic equilibrium (LTE) effects become relevant already for densities $\gtrsim10^{8}$~cm$^{-3}$. The cooling through pure rotational lines of NH$_3$ has therefore been recalculated numerically using the \textsc{RADEX} software \citep{vanderTak2007} in the optically thin limit, see Appendix~\ref{app:NH3_cool}. Cooling by rovibrational lines of H$_2$O, $^{12}$CO, and $^{13}$CO is computed using the tabulated values of \citet{Neufeld1993} which take into account opacity effects. Additionally, the gas can be cooled though collisions with dust grains which subsequently radiate away the heat.

The temperature of the dust is calculated from the equilibrium between heating through absorption of photons, thermal collisions with the gas which can both heat and cool the dust, and cooling through infrared emission \citep{Godard2019}. The FIR radiation field of the 100~K black body is of particular importance for the heating for dust grains in the pre and post-shock regimes as it sets a minimum dust temperature of $\sim22$~K. A dust temperature of $<20$~K would imply that even the most volatile species like CO and N$_2$ are frozen out onto dust grains. However, observations of embedded protostellar systems suggest that CO and N$_2$ are not frozen out in the inner regions of such systems \citep[e.g.,][]{vantHoff2018}. A higher dust temperature would result in more ice species being desorbed prior to the shock, but the effect on the shock structure and chemistry is negligible.

\begin{figure*}
\includegraphics[width=0.49\linewidth]{{Tn_Tgrain}.pdf}
\includegraphics[width=0.49\linewidth]{{x_SO__x_SO2__x_OH__x_SH_}.pdf}
\caption{
{\it Left:} Temperature and density structure in the fiducial $J$-type shock. The shock starts at 0~AU and ends at about 5~AU. The dust temperature does not increase enough for thermal sublimation of SO and SO$_2$.
{\it Right:} Abundance profiles of SO (solid) and SO$_2$ (dashed) and the key species for gas-phase formation of these species: SH (dot-dashed) and OH (dotted). The region where $T_\mathrm{gas} > 50$~K is indicated with the shaded blue region.
}
\label{fig:fidu_shock_T_SO_SO2}
\end{figure*}

\begin{table}
\centering
\caption{Fiducial model parameters and explored parameter range}
\label{tab:phys_params}
\begin{tabular}{llll}
\hline \hline
 & Units & Fiducial & Range \\
\hline
$n_\mathrm{H}$\ & cm$^{-3}$ & $10^{7}$ & $10^{5} - 10^{8}$ \\
$\zeta_{\mathrm{H}_2}$\ & s$^{-1}$ & $10^{-17}$ & -- \\
$G_0$\ & Mathis & 1 & $10^{-3} - 10^{2}$ \\
$V_\mathrm{s}$\ & km~s$^{-1}$ & 3 & $1 - 10$ \\
\hline
\end{tabular}
\end{table}

\subsection{Input parameters}
\label{subsuec:inputparam}
The range of physical parameters explored in this paper is presented in Table~\ref{tab:phys_params}. Important physical parameters are the initial proton density $n_\mathrm{H}$, the cosmic ray ionization rate of H$_2$ $\zeta_{\mathrm{H}_2}$,  the strength of the local incident radiation field, and the shock velocity $V_\mathrm{s}$.
Depending on the mass of the source and size of the disk, the density of infalling envelope material impacting the disk can be $\sim10^{5}-10^{8}$~cm$^{-3}$ \citep[e.g.,][]{Harsono2015}. Therefore, the investigated range of $n_\mathrm{H}$\ covers $\sim10^{5}-10^{8}$~cm$^{-3}$, with the fiducial value at $10^7$~cm$^{-3}$.
The radiation field is parameterized as a combination of the ISRF multiplied with a factor $G_0$\ \citep{Mathis1983} and infrared emission from the disk (which is constant for all models).
The strength of the local UV radiation field at the disk-envelope interface is highly uncertain and (among other things) dependent on the distance to the source of UV radiation (see Sect~\ref{subsubsec:geometry}). Without extinction, the local $G_0$\ value could be as high as $10^4$ at $\sim100$~AU \citep{Visser2012}. However, taking into account the extinction the local strength will likely not be much higher than a $G_0$\ of $\sim100$. Therefore, a large range in $G_0$\ is considered: $10^{-3}-10^{2}$, with a fiducial value of $G_0 = 1$.
The fiducial $V_\mathrm{s}$\ is set to $3$~km~s$^{-1}$, which is roughly equal to the velocity of the infalling envelope at $100$~AU for a $0.5$~M$_\odot$ star. Shock velocities of $1-10$~km~s$^{-1}$\ are considered, which correspond to an infalling envelope at $10-1000$~AU. The initial gas temperature is set to 25~K.

Input abundances of smaller molecules and atoms are set to match typical low-mass dark cloud conditions \citep{vanderTak2003,Boogert2015,Navarro2020,Tafalla2021,Goicoechea2021}. The initial gas-phase abundance of atomic S and O is set to $10^{-6}$ with respect to $n_\mathrm{H}$, with most of the oxygen and carbon reservoirs locked up in refractory grain cores or ices such as H$_2$O and CH$_4$ \citep[$10^{-4}$ and $10^{-6}$, respectively;][]{Boogert2015}. H$_2$S ice is assumed to be the dominant sulfur carrier with an abundance of $\sim2\times10^{-5}$ \citep[e.g.,][]{Vidal2017, Navarro2020}. The abundance of both SO and SO$_2$ ice was set to $10^{-7}$ \citep[e.g.,][]{Boogert2015,Rubin2019,Altwegg2019}, with the initial gas-phase abundance at $10^{-9}$ \citep{vanderTak2003}. The full list of input abundances is presented in Appendix~\ref{app:input_abundances}.

\begin{figure}
\includegraphics[width=1\linewidth]{{Tdust_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00}.pdf}
\caption{Maximum dust temperature reached (in color) in shock models as function of initial $n_\mathrm{H}$\ and $V_\mathrm{s}$. All other physical parameters are kept constant to the fiducial values and listed on top of the figure. The black cross indicates the position of the fiducial model.
}
\label{fig:Vs_nH_Tdust}
\end{figure}

\begin{figure*}
\includegraphics[width=0.49\linewidth]{{SO_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00}.pdf}
\includegraphics[width=0.49\linewidth]{{SO2_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00}.pdf}
\caption{Maximum abundance reached (in color) of SO (left) and SO$_2$ (right) in shock models as function of initial $n_\mathrm{H}$\ and $V_\mathrm{s}$. All other physical parameters are kept constant to the fiducial values and listed on top of the figure. The black cross indicates the position of the fiducial model. The dashed black line shows the ice line, i.e., where 50\% of the ice is thermally desorbed into the gas in the shock.
}
\label{fig:Vs_nH_SO_SO2}
\end{figure*}

\section{Results}
\label{sec:results}
\subsection{Temperature and density}
The gas and dust temperature, $T_\mathrm{gas}$ and $T_\mathrm{dust}$, respectively, and density structure of the fiducial shock model are shown in the left of Fig.~\ref{fig:fidu_shock_T_SO_SO2}.
At the start of the shock, $T_\mathrm{gas}$ increases to $\sim500$~K, which is in agreement with the analytic expression for a weakly magnetized and fully molecular shock derived by \citet{Lesaffre2013} from the Rankine-Hugoniot relations,
\begin{align}
T_\mathrm{gas,max} \approx 53 V_\mathrm{s}^2,
\label{eq:gas_temp}
\end{align}
where $V_\mathrm{s}$\ is the initial shock velocity in units of km~s$^{-1}$.
Following the jump in temperature, the gas is cooled down through radiation of rotational and rovibrational molecular lines and atomic lines. The most dominant coolant right after the shock front is H$_2$, while cooling by (optically thick) pure rotational and rovibrational lines of CO and H$_2$O take over as the temperature drops below $\lesssim400$~K. Cooling of the gas through gas-dust thermal coupling is negligible. Cooling through NH$_3$ in the optically thin limit is significant for those shocks with $V_\mathrm{s} \gtrsim 6$~km~s$^{-1}$\ since in those shocks the abundance of NH$_3$ is significantly increased through high-temperature gas-phase chemistry. The end of the shock is defined as the distance where $T_\mathrm{gas}$ drops below 50~K, which corresponds to $\sim3$~AU for the fiducial model. In the post-shock, the thermal balance between gas and dust is determined by heating of the dust through the FIR radiation field, gas-grain collisions that transfer the heat from dust to gas, and cooling of the gas through predominantly CO rotational transitions.

The dust temperature is very relevant for these shocks since it increases to values where thermal desorption of ices occurs. In the shock, the material compresses, increasing the density by up to two orders of magnitude (i.e., to about 10$^{9}$~cm$^{-3}$ in Fig.~\ref{fig:fidu_shock_T_SO_SO2}). Due to the thermal coupling between the gas and dust, $T_\mathrm{dust}$ increases to $\sim30$~K for the fiducial model, enough for thermal sublimation of volatile species such as CH$_4$, but not for more strongly bound ices such as H$_2$S, H$_2$O, and CH$_3$OH. However, as shown in Fig.~\ref{fig:Vs_nH_Tdust}, $T_\mathrm{dust}$ can become as large as $>70$~K in the highest-velocity ($\sim10$~km~s$^{-1}$) shocks in the densest ($10^{8}$~cm$^{-3}$ media, resulting in thermal sublimation of several ices including H$_2$S, SO, and SO$_2$.
Dust heating through UV radiation is only significant for strongest irradiated environments with $G_\mathrm{0} \gtrsim 50$ and only up to $T_\mathrm{dust}\lesssim25$~K. Since photodesorption of ices is negligible on timescales of the shock (see Eq.~\eqref{eq:tau_photodes}), thermal desorption is the dominant mechanism in releasing ices to the gas phase.

\subsection{Chemistry of SO and SO$_2$}
The abundance profiles of SO and SO$_2$ in the fiducial model are presented in the right part of Fig.~\ref{fig:fidu_shock_T_SO_SO2}. Toward the end of the shock, as the gas and dust are cooling down, a significant increase in the abundances of SO is visible up to the $\sim5\times10^{-8}$ level. The abundance of SO$_2$ does not increase above the dark cloud abundance of $10^{-9}$ \citep{vanderTak2003}. The maximum abundance reached in the shock for SO and SO$_2$ as function of different initial $n_\mathrm{H}$\ and $V_\mathrm{s}$\ is presented in Fig.~\ref{fig:Vs_nH_SO_SO2}. In the following subsections different parts of the parameter space are highlighted using the relevant chemical formation pathways in Fig.~\ref{fig:S_chem_shock}.

\subsubsection{Low-velocity shocks: $\sim3$~km~s$^{-1}$}
In low-velocity ($\sim3$~km~s$^{-1}$) shocks, thermal desorption of SO and SO$_2$ ice does not occur since $T_\mathrm{dust}$ only rises to $\lesssim35$~K. Any increase in abundance thus originates from gas-phase chemistry. Here, the relevant chemical reaction leading to the formation of SO is,
\begin{align}
\rm SH + O & \rightarrow \rm SO + H. \label{reac:SH_O}
\end{align}
The main formation pathway here of SH is via the green route of Fig.~\ref{fig:S_chem_shock}, that is, through the reaction of H$_2$CO with S$^+$. Since H$_2$CO only desorbs directly from the ice when $T_\mathrm{dust} \gtrsim 65$~K, H$_2$CO is formed through the gas-phase reaction of the CH$_3$ radical with atomic O. To get a significant amount of CH$_3$ in the gas, CH$_4$ ice needs to desorb \citep[at $T_\mathrm{dust} \gtrsim 25$~K;][]{Penteado2017} and subsequently photodissociate into CH$_3$ and atomic H. The S$^+$ ion originates from the photo-ionization of atomic S. The strongest increase in abundance through this route at intermediate densities ($n_\mathrm{H} \sim 10^7$~cm$^{-3}$). It is important to note that H$_2$CO is a representative here of any hydrocarbon reacting with S$^+$ to form SH.

Some SO$_2$ is also formed in low-velocity shocks through a reaction of SO with OH (see Reaction~\eqref{reac:SO_OH}). However, the abundance of SO$_2$ does not increase above the initial dark cloud abundance of $10^{-9}$ because no significant amount of OH is available at these shock velocities.

\begin{figure*}
\includegraphics[width=1\linewidth]{{S_chemistry_accretion_shocks_v3}.pdf}
\caption{Chemical reactions leading to the formation of gas-phase SO and SO$_2$. Species denoted as s-X are located in the ice mantles of dust grains. Reverse reactions are not shown for clarity. Red arrows denote chemical reactions with the annotated species, yellow arrows photodissociation reactions, and blue arrows ice desorption via either thermal or non-thermal mechanisms. Relevant chemical pathways are highlighted with a colored background. }
\label{fig:S_chem_shock}
\end{figure*}

\subsubsection{High-velocity shocks: $>4$~km~s$^{-1}$}
For shocks propagating at higher velocities ($\gtrsim4$~km~s$^{-1}$), both SO and SO$_2$ are efficiently formed through gas-phase chemistry, see Fig.~\ref{fig:Vs_nH_SO_SO2}. After the start of the shock, H$_2$O is readily formed through reactions of OH with H$_2$ \citep[][see also Fig.~\ref{fig:Vs_nH_H2S_H2O_SiO_H2CO}]{Flower2010}. As the shock cools down to below $\lesssim300$~K, the production of H$_2$O stops, but OH is still being formed through photodissociation of H$_2$O. This increases the OH abundance in the gas which stimulates the formation of SO and SO$_2$ through the red route of Fig.~\ref{fig:S_chem_shock},
\begin{align}
\rm S + OH & \rightarrow \rm SO + H,  \label{reac:S_OH} \\
\rm SO + OH & \rightarrow \rm SO_2 + H. \label{reac:SO_OH}
\end{align}
The highest abundances are achieved in less dense environments ($\lesssim 10^6$~cm$^{-3}$), with the maximum abundance of both SO and SO$_2$ dropping when moving toward intermediate densities ($\sim 10^{6}-10^{7}$~cm$^{-3}$). In the latter conditions, NH$_3$ becomes a dominant coolant in the tail of the shock. Therefore, the shock cools down more quickly and hence the region of favorable conditions for SO and SO$_2$ formation \mbox{($100 \lesssim T_\mathrm{gas} \lesssim 300$~K)} is reduced and their maximum abundances are lower.

At the highest densities ($n_\mathrm{H} > 10^{7}$~cm$^{-3}$), thermal desorption of sulfur-bearing ices becomes relevant for the chemistry (i.e., the blue route in Fig.~\ref{fig:S_chem_shock}). SO ice thermally sublimates as the dust temperature reaches $\sim37$~K, leading to a strong increase in its gas-phase abundance (see Fig.~\ref{fig:Vs_nH_SO_SO2}). Thermal desorption of SO$_2$ only occurs for the highest velocity shocks in the densest media. However, desorption of H$_2$S ice (at $T_\mathrm{dust}\sim47$~K) is also relevant for the gas-phase chemistry as subsequent photodissociation and reactions with atomic H lead to an increased abundance of SH and atomic S (i.e., the yellow route of Fig.~\ref{fig:S_chem_shock}).

\subsubsection{Dependence on UV radiation field}
As shown in Reactions~\eqref{reac:SH_O}-\eqref{reac:SO_OH} and Fig.~\ref{fig:S_chem_shock}, gas-phase formation of SO and SO$_2$ is dependent on radicals such as OH and SH. These radicals can be created in various ways, including high-temperature chemical reactions \citep{Prasad1980,Hartquist1980}. However, a more dominant physical process for enhancing the abundance of OH and SH is the photodissociation of H$_2$O, H$_2$S, and interestingly also CH$_4$. This process is dependent on the strength of the local UV radiation field, which is parametrized here with $G_0$.

In Fig.~\ref{fig:Vs_nH_SO_G01e-2}, the maximum abundance of SO as function of $V_\mathrm{s}$\ and $n_\mathrm{H}$\ is presented for $G_0 = 10^{-2}$. Similar figures of both SO and SO$_2$ for various $G_0$\ are presented in Appendix~\ref{app:SO_SO2_G0}.
Decreasing the strength of the UV field decreases the amount of SO and SO$_2$ produced in high-velocity ($\gtrsim4$~km~s$^{-1}$) shocks due to less OH being produced through H$_2$O photodissociation. On the other end, increasing $G_0$ shifts the spot for efficient SO and SO$_2$ formation in the shock to higher densities to create the favorable conditions for their chemistry. Moreover, for $G_0 \gtrsim 10$ photodissociation of thermally desorbed H$_2$S (i.e., when $n_\mathrm{H}\gtrsim10^7$~cm$^{-3}$ and $V_\mathrm{s}\gtrsim4$~km~s$^{-1}$) significantly increases the abundance of atomic S (i.e., yellow route of Fig.~\ref{fig:S_chem_shock}) which leads to an increase in abundances of SO and in particular SO$_2$ (see Fig.~\ref{fig:Vs_nH_SO2_diffG0}).

\begin{figure}
\includegraphics[width=1\linewidth]{{SO_abun_species_max_Vs_vs_nH_dz1e-17_G01e-02_bB0e+00_paper}.pdf}
\caption{Similar figure as Fig.~\ref{fig:Vs_nH_SO_SO2}, but now for SO in shocks with a weaker UV field ($G_0 = 10^{-2}$).
}
\label{fig:Vs_nH_SO_G01e-2}
\end{figure}

\begin{table}
\centering
\caption{Input abundances of key Sulfur-bearing species}
\label{tab:S_input_abun}
\begin{tabular}{lcccccc}
\hline \hline
Case & S & SO & SO$_2$ & s-SO & s-SO$_2$ & s-H$_2$S  \\
\hline
Fiducial & 1(-6) & 1(-9) & 1(-9) & 1(-7) & 1(-7) & 2(-5)\\
Low-S & 1(-8) & 1(-9) & 1(-9) & 1(-7) & 1(-7) & 2(-5)  \\
High-S & 2(-5) & 1(-9) & 1(-9) & 1(-7) & 1(-7) & 1(-7)  \\
\hline
\end{tabular}
\tablefoot{a(b) represents $\mathrm{a\times10^b}$. Species denoted as s-X are located in the ice mantles of dust grains. All other abundances are the same as those presented in Appendix~\ref{app:input_abundances}.}
\end{table}

\begin{figure*}
\includegraphics[width=0.49\linewidth]{{SO_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00_S1e-8}.pdf}
\includegraphics[width=0.49\linewidth]{{SO2_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00_S1e-8}.pdf}
\includegraphics[width=0.49\linewidth]{{SO_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00_S2e-5}.pdf}
\includegraphics[width=0.49\linewidth]{{SO2_abun_species_max_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00_S2e-5}.pdf}
\caption{Maximum abundance reached (in color) of SO (left) and SO$_2$ (right) in shock models as function of initial $n_\mathrm{H}$\ and $V_\mathrm{s}$\ for an initial gas-phase atomic S abundance of $10^{-8}$ (top row) and $10^{-5}$ (bottom row). All other physical parameters are kept constant to the fiducial values and listed on top of the figure. The black cross indicates the position of the fiducial model. The dashed black line shows the ice line, i.e., where 50\% of the ice is thermally desorbed into the gas in the shock.
}
\label{fig:Vs_nH_SO_SO2_diffSabun}
\end{figure*}

At lower shock velocities ($V_\mathrm{s} \lesssim 4$~km~s$^{-1}$), water is not formed in the shock and hence photodissociation of H$_2$O does not increase the abundance of SO and SO$_2$. The increase of SO abundance is here due to the green route of Fig.~\ref{fig:S_chem_shock}, which is initialized by thermal desorption and subsequent photodissociation of CH$_4$.
This formation route is most relevant for $G_0 = 1$; for lower $G_0$, the UV radiation field is not strong enough to photodissociate significant amounts of CH$_4$.
For higher $G_0$, higher densities are required for the efficient production of SO through the green route.

\subsubsection{Dependence on initial conditions}
\label{subsubsec:init_conditions}
The abundance of all species, including SO and SO$_2$, is dependent on the initial abundances. The interstellar ice abundances of SO and SO$_2$ are not well known, with only a tentative detection for SO$_2$ \citep{Boogert1997,Zasowski2009}. Here,the ice abundances of SO and SO$_2$ are estimated at the $10^{-7}$ level based on what is found in cometary ices \citep{Calmonte2016,Rubin2019,Altwegg2019}. However, they are only relevant in the shocks where thermal desorption of these ices occurs (i.e., the blue route of Fig.~\ref{fig:S_chem_shock} and to the right of the dashed line in Fig.~\ref{fig:Vs_nH_SO_SO2_diffSabun}). For those shocks, increasing or decreasing the ice abundances with an order of magnitude will also result in an increase or decrease of the gas-phase abundances with an order of magnitude, given that the ice abundance is dominant over what is achieved through gas-phase chemistry alone.

For shocks where the abundance of SO and SO$_2$ is mainly increased through gas-phase chemistry (i.e., to the left of the dashed line in Fig.~\ref{fig:Vs_nH_SO_SO2_diffSabun}), the maximum abundance reached is mostly directly dependent on the initial abundance of atomic sulfur. To test the effect of initial atomic S abundance on the maximum abundances of SO and SO$_2$, shock models are calculated for a lower gas-phase atomic sulfur abundance (Low-S: $X_\mathrm{S} = 10^{-8}$) and assuming that almost all sulfur is atomic and in the gas phase (High-S: $X_\mathrm{S} = 2\times 10^{-5}$). The initial abundances for these cases are presented in Table~\ref{tab:S_input_abun}. The resulting maximum SO and SO$_2$ abundances for these models are shown in Fig.~\ref{fig:Vs_nH_SO_SO2_diffSabun}.

In the Low-S case, the maximum abundance of SO drops for both low and high velocity shocks (excluding higher densities where the abundance is increased through thermal ice sublimation). This is straightforward to interpret since both S and S$^{+}$ are main formation precursors of SO in both the red and green formation routes of Fig.~\ref{fig:S_chem_shock}, respectively. At lower densities ($\lesssim10^{6}$~cm$^{-3}$), the maximum SO$_2$ abundance drops in a similar way since less SO is formed. However, at intermediate densities ($\sim10^{7}$~cm$^{-3}$), slightly more SO$_2$ is formed in high velocity shocks compared to Fig.~\ref{fig:Vs_nH_SO_SO2}. This is because atomic S and SO are `competing' to react with OH to form respectively SO and SO$_2$. Dropping the initial atomic S abundance results in more SO$_2$ being formed, also because the majority of the gas-phase SO here originates from thermal ice sublimation.

In the High-S case, not only the chemistry but also the thermal structure of the shock is slightly altered since cooling through atomic S becomes significant. Furthermore, more SO is formed through both the red and green routes of Fig.~\ref{fig:S_chem_shock}. Interestingly, the maximum abundance of SO$_2$ attained decreases compared to Fig.~\ref{fig:Vs_nH_SO_SO2} since with more atomic S in the gas phase to react with OH, less OH is available to react with SO toward SO$_2$.

The initial abundances of other species are also important for the chemistry of SO and SO$_2$. Increasing or decreasing the amount of atomic oxygen results in respectively more or less OH and H$_2$O formed in the shock and thus directly affects the abundances of SO and SO$_2$. Moreover, reactions with atomic carbon are a main destruction pathway for SO \citep[forming CS;][]{Hartquist1980}, hence an increased initial atomic carbon abundance results in lower abundances of both SO and SO$_2$ in the shock.

In reality, the initial dark cloud abundances may also be altered during the infall from envelope to disk since both the temperature and the strength of the UV radiation field increase \citep[e.g.,][]{Aikawa1999,Visser2009,Drozdovskaya2015}.
To take this into account, a pre-shock model should be calculated. In Appendix~\ref{app:pre-shock_mod}, the effect of calculating such a pre-shock model on the abundance of SO attained in the shock is presented. Any alterations on the pre-shock conditions are only important for the chemistry of SO and SO$_2$ if the timescale over which the pre-shock is calculated is longer than about 10\% of the photodesorption timescale. For typical infalling envelopes, this is not expected to be relevant.

\subsection{Effect of grain size and PAHs}

The size of the dust grains has an effect on both the physical structure of the shock and on the chemistry \citep[e.g.,][]{Guillet2007,Miura2017}. In Fig.~\ref{fig:PAH_grain_dependence}, the abundance profiles of SO and SO$_2$ are shown for the fiducial model and for the same model while adopting a typical ISM grain size distribution \citep[computed using a single size of $\sim0.03$~$\mu$m;][]{Mathis1977,Godard2019}.
The decrease in grain size leads to stronger coupling between gas and dust and thus to a slightly higher dust temperature ($\sim35$~K against $\sim30$~K for $0.2$~$\mu$m grains).
Moreover, the increased gas-grain coupling results in the dust being a dominant coolant in the tail of the shock reducing the length of the shock ($\sim1$~AU against $\sim3$~AU for the fiducial model).
Nevertheless, the abundance of SO is increased in the shock, but the maximum abundance reached is about a factor of $2-3$ lower compared to the fiducial model. No significant increase is seen for SO$_2$. \citet{Miura2017} found that the dust temperature easily reaches $\sim50$~K in low-velocity shocks taking into account dust aerodynamics for ISM-size dust grains. The full treatment of dust physics, including aerodynamic heating and grain-grain interactions \citep{Guillet2007,Guillet2009,Guillet2011,Guillet2020,Miura2017}, will likely move the ice line of Fig.~\ref{fig:Vs_nH_SO_SO2} toward lower $n_\mathrm{H}$\ and $V_\mathrm{s}$, but is beyond the scope of this work.

\begin{figure}
\includegraphics[width=\linewidth]{{PAH_grain_x_SO__x_SO2__speciesvar}.pdf}
\caption{
Abundance profile of SO (solid) and SO$_2$ (dashed) for the fiducial model (blue) with a PAH abundance of $10^{-8}$ using a grain size of $0.2$~$\mu$m.
Overplotted are the same model using a typical ISM grain size of 0.03~$\mu$m (orange) and a model with a PAH abundance of $10^{-6}$ (green). All other parameters are kept at their fiducial value (see Table~\ref{tab:phys_params}).
}
\label{fig:PAH_grain_dependence}
\end{figure}

Contrary to dust grains, the effect of PAHs on the physical structure of $J$-type shocks is negligible since PAHs do not contribute to the cooling and only little to the heating if a strong UV field is present. However, PAHs do play a key role in the ionization balance and are therefore highly relevant for the chemistry \citep{Flower2003}. In Fig.~\ref{fig:PAH_grain_dependence}, the abundances of SO and SO$_2$ are also shown for the fiducial model with a PAH abundance of $10^{-6}$ \citep[equal to the value derived in the local diffuse ISM;][]{Draine2007}. The maximum abundance of SO is a factor $3-4$ lower when the abundance of PAHs is at the ISM level because the PAHs are dominating the ionization balance. Consequently, the abundance of other ions, include S$^+$, drops by more than an order of magnitude. Given that the green route of Fig.~\ref{fig:S_chem_shock} is the dominant SO formation route here and dependent on S$^+$, less SO and subsequently SO$_2$ are formed. For high-velocity shocks, this effect is not apparent since Reactions~\eqref{reac:S_OH} and \eqref{reac:SO_OH} dominate the formation of SO and SO$_2$ and are independent of ions.

\subsection{Other molecular shock tracers: SiO, H$_2$O, H$_2$S, CH$_3$OH, and H$_2$}
Other classical molecular shock tracers include SiO, H$_2$O, H$_2$S, CH$_3$OH, and H$_2$. Abundance maps similar to Fig.~\ref{fig:Vs_nH_SO_SO2} of SiO, H$_2$O, H$_2$S, and CH$_3$OH are presented in Appendix~\ref{app:H2S_H2O_SiO_H2CO}. SiO is a tracer of shocks with significant grain destruction since then the silicon which is normally locked in dust grains can react with the OH radical to form SiO \citep[e.g.,][]{Caselli1997,Schilke1997,Gusdorf2008_1,Gusdorf2008_2,Guillet2009}. It is often observed in the high velocity bullets of jets originating from young Class~0 protostars \citep[e.g.,][]{Guilloteau1992,Tychoniec2019,Taquet2020}. However, the abundance of SiO is not significantly increased in our shock models because most of the Si remains locked up in silicates in the dust grains.

Water is the most abundant ice in protostellar envelopes \citep[][]{Boogert2015,vanDishoeck2021}, but also frequently observed in outflow shocks \citep[e.g.,][]{Flower2010,Herczeg2012,Kristensen2012,Nisini2013,Karska2018}. Here, H$_2$O is efficiently produced in shocks with $V_\mathrm{s} \gtrsim 4$~km~s$^{-1}$\ (see Fig.~\ref{fig:Vs_nH_H2S_H2O_SiO_H2CO}) and very important for the gas-phase chemistry of SO and SO$_2$. Thermal desorption of H$_2$O is negligible.

H$_2$S is suggested as a main carrier of sulfur in ices \citep[e.g.,][]{Vidal2017}, despite being undetected thus far \citep{Jimenez-Escobar2011}. In the gas phase it is generally observed close to Class~0 protostars  where the emission may originate from thermal desorption \citep{Tychoniec2021}, or in outflow shocks \citep[e.g.,][]{Holdship2016}. In our shock models, gas-phase formation of H$_2$S becomes efficient at slightly higher velocities than for water ($V_\mathrm{s} \gtrsim 5$~km~s$^{-1}$, see Fig.~\ref{fig:Vs_nH_H2S_H2O_SiO_H2CO}). Moreover, for high-velocity shocks in dense media, H$_2$S ice is thermally sublimated.

Methanol is a tracer of lower-velocity ($<10$~km~s$^{-1}$) outflow shocks where ices are sputtered off the dust grains \citep[e.g.,][]{Suutarinen2014}. However, since sputtering is not relevant in our single-fluid $J$-type accretion shock models, no significant increase of CH$_3$OH abundance is evident except at the highest densities ($\gtrsim10^8$~cm$^{-3}$) and velocities ($\gtrsim10$~km~s$^{-1}$) where CH$_3$OH ice thermally sublimates.

Emission from warm H$_2$ is generally observed toward shocks in protostellar jets \citep[e.g.,][]{McCaughrean1994}. Contrary to the molecules discussed above, the abundance of H$_2$ remains constant along the shock and only thermal excitation occurs. Hence, H$_2$ can be a powerfull diagnostic of accretion shocks in inferring the temperature from a rotational diagram. The population of the lowest 50 rotational and rovibrational levels of H$_2$ are computed during the shock \citep{Flower2003}.
The rotational diagram of H$_2$ for the fiducial model is presented in Fig.~\ref{fig:H2_rot}. Since the temperature in this shock reaches about $\sim500$~K, levels up to $\sim6000$~K are collisionally populated. The population of all higher-$E_\mathrm{up}$ levels is set during the formation of H$_2$ on the dust grains following a Boltzmann distribution at 17248~K \citep[1/3 of the dissociation energy of H$_2$;][]{Black1987}. Using the rotational diagram of Fig.~\ref{fig:H2_rot}, a rotational temperature $\sim 390$~K can be derived for this shock.

\begin{figure}
\includegraphics[width=1\linewidth]{{H2_rot_diagram}.pdf}
\caption{Rotational diagram of H$_2$ created from the fiducial shock model. The levels of different vibrational states are indicated with different symbols and colors. Note that only the pure rotational levels with $E_\mathrm{u}/k_\mathrm{B} \lesssim 6000$~K are collisionally populated. The fit to the pure rotational levels is shown in gray line with the derived rotational temperature annotated.
}
\label{fig:H2_rot}
\end{figure}

\section{Discussion}
\label{sec:discussion}
\subsection{Comparison to SO and SO$_2$ with ALMA}
Emission of warm ($T_\mathrm{ex} > 50$~K) SO and SO$_2$ around the disk-envelope interface has been suggested as a possible tracer of accretion shocks \citep{Sakai2014,Sakai2017,Bjerkeli2019,Oya2019,Elizabeth2019}. Here, we have shown that the abundance of both SO and SO$_2$ can increase in shocks in typical inner envelope conditions. The abundance of SO is estimated to be $\sim10^{-8}$ in the suggested accretion shock around the L1527 Class 0/I protostar \citep{Sakai2014}, but this is uncertain since the density of H$_2$ was guessed. Furthermore, by itself this does not provide strong constraints on the physical conditions of the shock (see Fig.~\ref{fig:Vs_nH_SO_SO2}), other than that a weak UV field should be present if SO ice is not thermally sublimated ($G_0 > 10^{-2}$; Fig.~\ref{fig:Vs_nH_SO_diffG0}). However, it remains difficult to derive abundances with respect to $n_\mathrm{H}$\ from observations.

Recent ALMA observations show that the amount of warm SO$_2$ seems to increase with the bolometric luminosity \citep[i.e., stronger UV field;][]{Elizabeth2019}. This is in line with our results since the abundance of SO$_2$ only increases when a significant UV field is present (i.e., $G_0 \gtrsim 1$, see Fig.~\ref{fig:Vs_nH_SO2_diffG0}). Especially for higher velocity shocks ($>4$~km~s$^{-1}$) at higher densities ($>10^7$~cm$^{-3}$) the maximum abundance of SO$_2$ increases with 2 orders of magnitude between $G_0 = 1$ and $G_0 = 100$.
However, besides a significant UV field, a shock velocity of $V_\mathrm{s} \gtrsim 4$~km~s$^{-1}$\ is necessary to increase the abundance of SO$_2$ and the maximum abundance reached in the shock is also dependent on the initial density $n_\mathrm{H}$.

Comparing the ratio of observed column densities to those derived from our shock models can more accurately constrain the physical conditions in a shock.
In Fig.\ref{fig:Vs_nH_SO_SO2_column_ratio}, the column density ratio of SO$_2$/SO in the shock is presented as function of $V_\mathrm{s}$\ and $n_\mathrm{H}$\ for $G_0 = 1$ and $G_0 = 100$. The only protostellar source where both SO and SO$_2$ have been detected related to a possible accretion shock is Elias~29 \citep{Oya2019}, where a column density ratio of $0.5^{+0.4}_{-0.2}$ is derived.
When $G_0 = 1$, this would imply a low-density shock ($<10^6$~cm$^{-3}$) propagating at either low ($<2$~km~s$^{-1}$) or high ($>7$~km~s$^{-1}$) velocities, see upper panel in Fig.~\ref{fig:Vs_nH_SO_SO2_column_ratio}. For $G_0 = 100$, shocks propagating at higher velocities ($>4$~km~s$^{-1}$) at high densities ($>10^7$~cm$^{-3}$) produce SO$_2$/SO column density ratios similar to that of Elias~29 \citep[][see lower panel in Fig.~\ref{fig:Vs_nH_SO_SO2_column_ratio}]{Oya2019}.

\begin{figure}
\includegraphics[width=\linewidth]{{SO2_SO_Nx_Vs_vs_nH_dz1e-17_G01e+00_bB0e+00}.pdf}
\includegraphics[width=\linewidth]{{SO2_SO_Nx_Vs_vs_nH_dz1e-17_G01e+02_bB0e+00}.pdf}
\caption{
Ratio of column densities of SO$_2$ and SO as function of $n_\mathrm{H}$\ and $V_\mathrm{s}$ for $G_0 = 1$ (top) and $G_0 = 100$ (bottom). All other physical parameters are kept constant to the fiducial values and listed on top of the figure. The black cross indicates the position of the fiducial model.
}
\label{fig:Vs_nH_SO_SO2_column_ratio}
\end{figure}

Since both SO and SO$_2$ emission is also linked to outflow activity and passive heating in the inner envelope \citep{Codella2014,Tabone2017,Lee2018,Taquet2020,Harsono2021}, high spatial resolution observations with ALMA are necessary to both spatially and spectrally disentangle the different protostellar components and determine their emitting area.
Moreover, to robustly test if the SO and SO$_2$ emission traces the accretion shock, key species for their gas-phase formation such as H$_2$S and H$_2$CO should be observed on similar scales. This also allows for more accurately constraining the physical conditions of a shock.

\subsection{Predicting H$_2$, H$_2$O, and [S\,{\sc i}] with JWST}
With the launch of JWST, near-infrared (NIR) and MIR shock tracers such as H$_2$, H$_2$O, and [S\,{\sc i}] can be used to search for accretion shocks. Although the abundance of H$_2$ does not increase in accretion shocks, it is still thermally excited and therefore a good shock tracer at NIR and MIR wavelengths \citep[e.g.,][]{McCaughrean1994}.
Observing the rotational sequence of H$_2$ in the NIR and MIR could thus put constraints on the physical properties of the shock. For low-velocity shocks ($\lesssim5$~km~s$^{-1}$), most of the strong H$_2$ transitions (i.e., 0-0~S(3) and 0-0~S(5)) are located in the JWST/MIRI range ($5-28$~$\mu$m).
For higher velocity shocks ($\gtrsim5$~km~s$^{-1}$), also vibrational levels of H$_2$ get populated and the strongest H$_2$ transitions shift toward the NIRSpec range of JWST ($1-5$~$\mu$m).

Warm water is also a well-known and important tracer of shocks \citep[e.g.,][]{Herczeg2012,Kristensen2012,Nisini2013,vanDishoeck2021}. Observing H$_2$O toward an accretion shock is a clear indication of a high-velocity shock ($\gtrsim4$~km~s$^{-1}$, see Fig.~\ref{fig:Vs_nH_H2S_H2O_SiO_H2CO}). Warm water should be easily detectable with JWST as both the vibrational band around $6$~$\mu$m and several pure rotational transitions at $>10$~$\mu$m fall within the MIRI range ($5-28$~$\mu$m). Moreover, the detection of MIR lines of the OH radical can be an indication of H$_2$O photodissociation \citep{Tabone2021}, and therefore be spatially co-located with emission of warm SO and SO$_2$ in ALMA observations.

An alternative shock tracer in the JWST/MIRI band is the [S\,{\sc i}]~$25~\mu$m transition. It is often observed in protostellar outflows \citep[e.g.,][]{Neufeld2009,Lahuis2010,Goicoechea2012}, where the intensity of the line can range from a few \% of the H$_2$ 0-0~S(3) and 0-0~S(5) lines to a factor of a few higher. It is therefore uncertain whether [S\,{\sc i}]~$25~\mu$m will be detectable toward accretion shocks, also given that the sensitivity of MIRI drops at the highest wavelengths. Moreover, at $25$~$\mu$m, the angular resolution of JWST is $\sim1"$ (i.e., 300~AU at a distance of 300~pc) which complicates the spatial disentanglement of an accretion shock with outflow emission.

\section{Summary}
\label{sec:summary}
We have modeled low-velocity ($\leq 10$~km~s$^{-1}$) non-magnetized \mbox{$J$-type} shocks at typical inner envelope densities ($10^{5}-10^{8}$~cm$^{-3}$) using the Paris-Durham shock code to test SO and SO$_2$ as possible molecular tracers of accretion shocks. The main conclusions of this work are as follows:
\begin{itemize}
\item In low-velocity ($\sim3$~km~s$^{-1}$) shocks, SO can be efficiently formed at intermediate densities ($\sim10^7$~cm$^{-3}$) through the SH radical reacting with atomic O. Here, SH is formed through S$^+$ reacting primarily with H$_2$CO; though the latter species is a representative of any hydrocarbon.

\item Both SO and SO$_2$ can be efficiently formed through reactions of atomic S with OH in high-velocity ($\gtrsim4$~km~s$^{-1}$) shocks in low-intermediate dense environments ($\lesssim10^7$~cm$^{-3}$)
. The formation of SO and SO$_2$ occurs in the end of the shock, where the abundance of OH is enhanced through photodissociation of earlier formed H$_2$O.

\item Thermal desorption of SO ice can occur in high-velocity ($\gtrsim4$~km~s$^{-1}$) shocks at high densities ($\gtrsim10^7$~cm$^{-3}$), while thermal desorption of SO$_2$ ice is only relevant at the highest shock velocities ($\gtrsim10$~km~s$^{-1}$) and highest densities ($\gtrsim10^8$~cm$^{-3}$).

\item The chemistry of both SO and SO$_2$ through all formation routes is strongly linked to the strength of the local UV radiation field since the formation of both the OH and SH radicals is linked to photon processes such as photodissociation and photoionization. In particular, SO$_2$ is only formed in the shock through gas-phase chemistry if the strength of the local UV radiation field is greater or equal to the ISRF.

\item The composition of infalling material, in both gas-phase species like atomic O and S and in the ices such as H$_2$S, CH$_4$, SO, and SO$_2$, is highly relevant for the chemistry of SO and SO$_2$ in accretion shocks.

\item Observations of warm SO and SO$_2$ should be complemented with key species for their formation such as H$_2$S and H$_2$CO. Moreover, the launch of JWST will add additional NIR and MIR accretion shock tracers such as H$_2$, H$_2$O, and [S\,{\sc i}]~$25~\mu$m.
\end{itemize}

Our results highlight the key interplay between both physics and chemistry in accretion shocks. The abundance of gas-phase molecules such as SO and SO$_2$ is not solely determined through high-temperature gas-phase chemistry, but also thermal sublimation of ices and photodissociation through UV radiation play an important role. Additional high-angular resolution observations with ALMA are necessary to spatially disentangle the disk from the envelope in embedded systems in order to assess the physical properties of accretion shocks at the disk-envelope interface. Moreover, future facilities such as JWST will provide additional NIR and MIR shock tracers such as H$_2$, OH, and H$_2$O. It is crucial to attain the physical structure of accretion shocks since it determines the chemical composition of material that enters the disk and is eventually incorporated in planets.

\begin{acknowledgements}
The authors would like to thank the anonymous referee for their constructive comments on the manuscript. The authors would also like to thank G. Pineau des For{\^e}ts for valuable discussions about the project. Astrochemistry in Leiden is supported by the Netherlands Research School for Astronomy (NOVA). MvG and BT acknowledge support from the Dutch Research Council (NWO) with project number NWO TOP-1 614.001.751.
\end{acknowledgements}

\bibliographystyle{aa}

redpajama_set_name: RedPajamaArXiv


text:
OSI Grant Helps Expand North Carolina's DuPont State Forest by 400 Acres
Related States and Countries
Resilient Landscapes Funds
This News protects
This News involves
DuPont Property Protected by OSI
After a dozen years of effort, a key, climate-resilient property is saved, forever
HENDERSON & TRANSYLVANIA COUNTIES, NC (Feb. 13, 2018)—Grant support from the Open Space Institute (OSI) has led to the expansion of a North Carolina state forest called DuPont State Recreational Forest, along the North and South Carolina border. The land also expands a 100,000-acre corridor of conserved land, which will remain a haven for sensitive plants and animals, even as climate change occurs.
OSI's grant went to Conserving Carolina for the protection of the 402-acre "Continental Divide" property. Conserving Carolina had been working to protect the land for a dozen years, during which time the land had a succession of owners, including a post-recession bank foreclosure.
"This project highlights the importance of land conservation in an era of climate change, not only for communities and recreation, but also for wildlife," said Peter Howell, executive vice president of OSI. "This project broadens the connection between conserved lands in North and South Carolina, which will create critical havens for wildlife in the wake of climate change. We applaud Conserving Carolina's efforts on this project and their overall commitment to this important landscape."
Across North Carolina, OSI has conserved 9,000 acres of climate-resilient lands. Across the greater Southeast, OSI has conserved nearly 25,000 acres of these climate-resilient lands.
The Continental Divide tract is so named because directly adjacent to the eastern side of the Eastern Continental Divide, a geologic separation running along the Blue Ridge Mountains. Waters on the eastern side of the Divide flow east towards the Atlantic, while waters on the western side flow west towards the Gulf of Mexico.
The newly-protected property also helps link DuPont Forest to more than 100,000 acres of existing conserved lands along the North Carolina-South Carolina state line. Public lands in this corridor include Jones Gap State Park, Caesar's Head State Park, Mountain Bridge Wilderness Area, Headwaters State Forest, Greenville Watershed, Jocassee Gorges, and Gorges State Park—and, further west, Sumter and Nantahala National Forests. The Continental Divide property also borders thousands of acres of private conservation land, including two summer camps.
In addition to OSI's grant, funding for the 402 acres came from the N.C. Forest Service and generous private donations from Fred and Alice Stanback; Marilyn Westphal and Mark Simpson; and Maurice Loiselle and Karen Topol.


Recreation Professionals of Ontario (RPO), formerly known as Activity Professionals of Ontario, is pleased to announce its 1st Annual Convention to be held in Toronto, Ontario October 17th -October 19th, 2018.
We would like to invite leisure recreation providers from all healthcare settings, students, educators and allied health professionals to join us by submitting proposal presentations as they relate to RPO's standards of practice.
Topics include but are not limited to: recreation assessments, documentation, development and implementation of recreation programs, evaluation and quality improvement, professional development, innovative programs, as well as legal responsibilities and legislative acts as they are applied in different healthcare settings.
Deadline for submissions is Thursday February 15, 2018.
Recreation Professionals of Ontario (RPO) is a professional organization for leisure recreation providers in healthcare settings.


Do you or somebody you're keen on undergo from the ache of arthritis? Relying in your age and the development of this illness, you may even have it now and never understand it. Do you may have ache in your fingers, knees, or different joints that seems to come back and go? Is it worse when the climate is chilly or if you overuse the joints? If that's the case, likelihood is good that you've got arthritis.
Most individuals don't understand that their weight loss plan can both assist or worsen many well being issues, together with arthritis. Though arthritis is just not one thing that medical science can truly treatment, there are methods that this illness may be managed.
We've made a listing of the highest 12 meals you must eat loads of to cut back the signs of arthritis. All the following meals comprise anti-inflammatory compounds that can reduce the ache and enhance the immune system.
Maintain studying and discover out how one can cut back irritation and enhance your mobility just by including the next meals to your weight loss plan.
That is an outdated wives story that has lately been backed up by science. The journal Arthritis & Rheumatism printed a double blind examine discovering that those that consumed no less than two eight ounce servings every day over the 16 week examine interval had a lot decrease ache ranges than those that consumed a placebo. Understand that these are tart cherries we're speaking about, not the candy type that most individuals purchase within the grocery store. You'll be able to eat a half cup of recent, frozen, canned, or dried tart cherries every day or drink eight ounces of juice.
British Individuals Underestimate Their Calorie Consumption. What About People?
Four Ideas For A A lot Higher And More healthy Rest room!


text:
Losing Out on a Pulitzer Prize: Ignoring the IRS Scandal
DIARY / alanjoelny // Posted at 4:30 pm on August 26, 2014 by alanjoelny
The latest revelations in the never-ending IRS Scandal are pretty headline-worthy, but hardly a pip is being heard from the MSM, again. First, Judicial Watch has revealed, and the Department of Justice has confirmed, that the missing emails of Lois Lerner do indeed exist; second, that the content of one of Lois Lerner's Blackberrys was destroyed after the Congressional investigation began in 2012.
The entire scandal has continuously had the makings of prize-winning news: targeting citizens, evidence disappearing, perjury, and more. Yet few of the leading "news" outlets are bothering to cover the scandal with any journalistic depth.
On the subject of Lerner's emails, Judicial Watch stated that,
"Department of Justice attorneys for the Internal Revenue Service told Judicial Watch on Friday that Lois Lerner's emails, indeed all government computer records, are backed up by the federal government in case of a government-wide catastrophe. The Obama administration attorneys said that this back-up system would be too onerous to search. The DOJ attorneys also acknowledged that the Treasury Inspector General for Tax Administration (TIGTA) is investigating this back-up system."
This is in direct contradiction to what has been declared by Lerner and the current head of the IRS, among others, have stated about the emails and their recoverability, as well as possible perjury. "Current IRS Commissioner John Koskinen testified before the House Government Oversight Committee in June that the emails during the key period when the targeting occurred were "lost" due to a hard drive crash in 2011."
With regard to Lerner's Blackberry, apparently the IRS submitted sworn declarations late last Friday as a response to Judge Emmet Sullivan, who is overseeing the case involving Judicial Watch v. IRS. In these sworn declarations, we find that Lois had two Blackberries. One was wiped clean after the Congressional inquiries began, without any attempt at data recovery. The second was issued in 2012, which the IRS still has. From the NY Observer:
"In two elusive and nebulous sworn declarations, we can glean that Ms. Lerner had two Blackberries. One was issued to her on November 12, 2009. According to a sworn declaration, this is the Blackberry that contained all the emails (both sent and received) that would have been in her "Outlook" and drafts that never were sent from her Blackberry during the relevant time.
With incredible disregard for the law and the Congressional inquiry, the IRS admits that this Blackberry "was removed or wiped clean of any sensitive or proprietary information and removed as scrap for disposal in June 2012." This is a year after her hard drive "crash" and months after the Congressional inquiry began.
The IRS did not even attempt to retrieve that data. It cavalierly recites: "There is no record of any attempt by any IRS IT employee to recover data from any Blackberry device assigned to Lois Lerner in response to the Congressional investigations or this investigation," according to Stephen Manning, Deputy Chief Information Officer for Strategy & Modernization."
Unfortunately, these bombshells only serve to re-emphasize two things we already knew. 1) the government is not above lying and cover-ups; 2) no one in the mainstream media has the fortitude to cover the story in-depth. With CNN, CBS, and ABC News having all have direct ties to the Obama Administration over the years, we certainly won't see any Pulitzer Prize winning investigations on the IRS Scandal at all.
Tags: DOJ IRS judicial watch
AOC Tries to Make Her Dismal Poll Numbers Out to Be An Illusion of Trump's
A Fox 10 Reporter Had Explicit Words for Her Bosses Who Want Her to Hide Her Right-Leaning Connections
The Real FBI/DOJ Scandal
Paul Montagu
Congress Demands Answers over IRS's "Collusive" Attempt to Target Churches for Angry Atheists
Matthew Clark
The Hill: House Dems still seething over AOC chief of staff
hotair.com
Biblical Economics & Finance: Theories Driving Economics Today
finance.townhall.com
Brutal: Cocaine Mitch's Liberal Opponent Face-Plants Out of the Gate, Bails on MSNBC Interview
Historian Jon Meacham says Trump's tied for 'most racist president in American history' (and people have thoughts) [video]


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29 Nov WARF responds to rejection of European patent claims
Posted at 11:20h in Biotech, Legal, Press release	by	WTN News 0 Comments
Madison, Wis. – The Wisconsin Alumni Research Foundation issued the following statement following the rejection of its stem cell patent claims before the European Patent Office.
"The Wisconsin Alumni Research Foundation (WARF) is disappointed in the decision of the Enlarged Board of Appeal of the European Patent Office (EPO) rejecting the claims of WARF's European Patent Application No. 96903521.1. WARF currently is considering various options in response to this decision.
"WARF emphasizes that this ruling by the EPO Enlarged Board of Appeal was based on European Union patent rules that are peculiar to Europe. There is no counterpart in United States patent law and therefore the EPO decision does not in any way affect WARF's patent rights in the United States.
"We have more than 40 issued patents directed to stem cells in 12 countries with more than 200 cases pending all over the world," states WARF General Counsel Michael Falk. "This decision represents a ruling in just one of these cases and in just one jurisdiction on grounds that do not apply in other jurisdictions."
According to WARF, the opinion of the Enlarged Board of Appeal focused on the issue of the patentability of cells made using an embryo. "The Board made no determination of the patentability of claims based on any of the traditional criteria used to assess patentability – usefulness, novelty, and non-obviousness. In fact, the opinion makes clear that its decision does not address the question of patentability in general of inventions relating to human stem cell cultures."
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the two peoples, which endured for 750 years.
Special Cable to Universal Service.
stood the realization by them of our position as it was.
which led up to it.
rible war" waa probably a bluff.
as a fighter and a diplomat.
declaration of war upon Egypt.
tion of war against India.
led by words and phrasea.
and I could not be a party to that.
basis. That was my own attitude.
been talked about so freely?
my position In signing the treaty.
looked for the repeal of the union.
the name of tha Irish Republic.
be reaponaible to the parliament.
we have gained that gives us our.
sing the wonders to come.
to go In leather aprons.
clownlshnrss ns he could devise.
one, at least, living In a cottage.
there are no longer any "orders."
we aro on tht way.
That takes you back a long way.
any other walk of Ufa.
In his heyday that "laboring men"
oominlttee of the town nowiMttl.
Ireland," Says Dashing Irish CMefbfc.
guest of a free people.
we can go ahead snd gain.
tionarv. no matter what we ias?
a free and a good nat on w?


𝕭𝖚𝖙𝖙𝖊𝖗𝖋𝖑𝖎𝖊𝖘 𝖆𝖓𝖉 𝕾𝖐𝖚𝖑𝖑𝖘. 🦋💀🦋 💀🦋💀 🦋💀🦋 One of my all time favourite combos. Did you know the the Skulls symbolise mankinds mortality and the butterfly represents rebirth or new life. Beautiful!
𝕯𝖆𝖉𝖘 𝕽𝖔𝖈𝖐. 💀 🖤 💀 Father's Day isn't far away, get organised with a wicked personalised print. Shop link in bio.
𝕾𝖙𝖆𝖞 𝖂𝖊𝖎𝖗𝖉. ☠ 🖤 ☠ Keeping it weird since 1976, how about you?


text:
The Wayne County Courthouse is located in Wooster, Ohio and was constructed to Thomas Boyd's design from 1877 to 1879. The building is designed in classic Second Empire style and is composed of sandstone. The architect originally designed a symmetrical building separate from the old north annex of the previous courthouse. The reluctant county officials cited money issues and ordered the new building to be built connected to the old, thus giving it an offset appearance.

The entrances are flanked by the Atlantes supporting a pediment. The first floor consists of smooth stone blocks. The windows are high arched and set back into the wall, above each is a small arch with a decorative keystone.

The second and third floor is of a rougher, darker stone than the first. Doric and Corinthian columns flank the windows around the facade. The second floor windows are high arched and recessed. Here the buildings on either side of the tower differ, the northern half ending with a hipped roof, the southern half continuing on above.

The third floor of the southern end contains rectangular recessed windows, the roof resting on a decorative moulding above. On the southern side sits a broken pediment with a griffin peering out below. Resting on the pediment are two figures representing Justice, one holding the scales of justice, the other the Ten Commandments. The windows peeking out of the roof are round portholes.

A high tower sits, oddly enough, at the end of the roofing detail, but correctly in the middle of the court complex. It rests on a broken pediment containing an urn. The tower rises two levels to become a clock tower, and then curves in to brace a cupola with a weather vane capping it.

References

External links

Courthouses on the National Register of Historic Places in Ohio
Buildings and structures in Wayne County, Ohio
National Register of Historic Places in Wayne County, Ohio
County courthouses in Ohio
Historic districts on the National Register of Historic Places in Ohio
Sandstone buildings in the United States
Clock towers in Ohio
Second Empire architecture in Ohio
Government buildings completed in 1879


Van Loo, Denis, Marijn Boone, Manuel Dierick, and Bert Masschaele. 2015. "X-Ray Engineering (XRE): a UGCT Spin-off Company." In 2nd UGCT Seminar : Book of Abstracts, ed. Matthieu Boone and Jan Van den Bulcke. Ghent, Belgium: Ghent University. Centre for X-ray Tomography (UGCT).
Van Loo, D., Boone, M., Dierick, M., & Masschaele, B. (2015). X-Ray Engineering (XRE): a UGCT spin-off company. In Matthieu Boone & J. Van den Bulcke (Eds.), 2nd UGCT seminar : book of abstracts. Presented at the 2nd UGCT seminar, Ghent, Belgium: Ghent University. Centre for X-ray Tomography (UGCT).
Van Loo D, Boone M, Dierick M, Masschaele B. X-Ray Engineering (XRE): a UGCT spin-off company. In: Boone M, Van den Bulcke J, editors. 2nd UGCT seminar : book of abstracts. Ghent, Belgium: Ghent University. Centre for X-ray Tomography (UGCT); 2015.
Van Loo, Denis, Marijn Boone, Manuel Dierick, et al. "X-Ray Engineering (XRE): a UGCT Spin-off Company." 2nd UGCT Seminar : Book of Abstracts. Ed. Matthieu Boone & Jan Van den Bulcke. Ghent, Belgium: Ghent University. Centre for X-ray Tomography (UGCT), 2015. Print.


Home » Did You Know » The Bill Chuck Files » Did You Know?
The Orioles' Chris Davis is one hit away from his first hit of the season. Davis is 0-17 with 11 strikeouts.
The Marlins got rid of their centerfield sculpture but added Comunidad 305, a section in the right-field grandstand where fans are encouraged to wave flags and play musical instruments.
Quick Quiz: Name the four MLB teams that have had five 90+ win seasons since 2010. Answer below.
"Bob Gibson Way" is the name of a new street named after the great Bob Gibson in St. Louis in ceremonies orchestrated by the Cardinals and Park Central Development in Rainbow Park at the intersection of Taylor and Gibson avenues. I would have presumed it would be at the intersection of High and Tight Avenues.
Speaking of Gibby, Jacob deGrom has now made 26 straight quality starts and that ties him with Bob Gibson for the longest streak in MLB history. And these are truly starts of quality. Over that stretch he has an ERA of 1.55 and a WHIP of 0.87. He has struck out 237 of the 708 batters he's faced and allowed just 128 hits (.193 BAA) and 8 homers (four to righties and four to lefties).
The Angels' lease at Angel Stadium expires after next season, and the team is considering whether to remain in Anaheim or move to a new ballpark in Long Beach, California. I don't care if they move, I just want them to change their name again, just to drive everyone batty (pun intended).
Clarence Haskett has been serving fans beer at Baltimore Orioles games for 45 years. And now he has a beer named for him. Haskett, better known by his nickname "Fancy Clancy" is the inspiration behind Fancy Clancy Pilsner available on tap at Escutcheon Brewery in Winchester, Virginia and in some bars, mostly around the Baltimore area.
Happy 81st birthday to Ron Hansen, who on July 30, 1968, while playing short for the Washington Senators pulled off an unassisted triple play against the Cleveland Indians. Treat yourself to something special if you knew the ball was hit by Joe Azcue.
In seven games this season, the Astros have scored 15 runs.
In their first eight games, the Blue Jays have already been no-hit through six innings four times.
According to court docs obtained by TMZ Sports, the Dodgers are suing a promotions company after they claim they were stiffed out of 42,000 Lasorda bobbleheads. The Dodgers says it entered into an agreement with Plan P2 Promotions to make thousands of "100% hand-painted, break-resistant poly-resin" Lasorda dolls but they claim the company never delivered the Tommy goods … and now, the MLB organization is suing for $175,000 for breaking the terms of the contract.
To infinity and beyond – Trevor Rosenthal, the Nationals reliever new to the team this season, has appeared in three games thus far. He's faced seven batters and the good news is that he's walked three of them. The bad news is that the other four have all gotten hits. The worse news is that all seven have scored, which means Trevor has an ERA of infinity.


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Home Music Department Community Outreach
About the Outreach Programs
The Department of Music offers a number of outreach programs in music for prospective students. Community outreach is prevalent in the music department with strong offerings in instrumental outreach that include among others, the Mary Jo Leahey Symphonic Band Camp, the New England Youth Wind Ensembles (Junior and Senior), and the String Project for young orchestral students. There is also the EcoSonic (Ecology/Sound) Playground Project™.
UMass Lowell Mary Jo Leahey Symphonic Band Camp
For almost 20 years the UMass Lowell Mary Jo Leahey Symphonic Band Camp has offered a week-long immersion in an honor's band music environment, the only one of its kind in the state. Our intensive, residential music camp offers a myriad of musical experiences for participants. Without audition, 130 students are able to enroll in courses such as conducting, score analysis, music theory, piano and more in addition to participating in concert band, wind ensemble, jazz bands, brass choirs and much more.
All students have the opportunity to work along side dozens of university faculty and staff, who embrace the opportunity to share their own enthusiasm and expertise. Executive Director Deb Huber ('89) has engaged in an aggressive commissioning program, allowing students the opportunity to perform multiple World Premieres of new wind-band works from renowned contemporary composers. New works are expected to be premiered in 2016 (the 20th anniversary of the camp) and in 2017. This, in addition to performing and learning with other students from widely diverse backgrounds, makes the program an unique experience.
Interested applicants may register on-line and download information from the Web site. Scholarships are available and contingent upon auditions, however auditions are not necessary to be accepted into the camp. The camp accepts approximately 130 student musicians, whose instruments include piccolo, flute, oboe, english horn, clarinet, bass clarinet, bassoon, all saxes, trumpet, french horn, trombone, euphonium, tuba, percussion, drum set, string bass, electric bass, piano and guitar. For more information please contact Executive Director, Deb Huber by email: DebraNicole_Huber@uml.edu or phone: 978-934-4133.
The New England Youth Wind Ensemble
The New England Youth Wind Ensemble founded in 2000 by Artistic Director and Conductor Deb Huber, is for high school students in grades 9-12. The ensemble meets on Monday evenings from 6:45 to 9 p.m. in Durgin Concert Hall. UMass Lowell's New England Youth Wind Ensembles are an integral component of the community outreach programs offered at the university. NEYWE reflects a microcosm of the community in musicianship and cultural diversity. Our Junior and Senior Wind Ensembles are thriving and vital components of a community organization that provide an educational learning experience for both ensemble participants and college music-student coaches. The collaboration with and instruction from college mentors is invaluable as is the opportunity for a child to sit next to a college musician, someone who cares about the child's successful learning and understanding, whose dream is to teach and whose passion is music.
Students of diverse backgrounds and varied levels of prowess are exposed to commissioned works, perform with soloists and are taught by university faculty and coached by college musicians. Participants build self-confidence and self-esteem, further musicianship and improve individual music skills in an environment of teamwork and learning. Emphasis is place on educational and artistic development as well as ensemble technique. Repertoire is chosen from diverse periods and styles, adjusted to meet the proficiency of participants. This Honor's band program inspires students from diverse backgrounds to work and achieve. Together. Auditions take place in January. The ensemble begins at the end of January and runs through April, with a finale concert taking place in May. Applications can be downloaded from the website. For more information contact the Artistic Director and Conductor by email: DebraNicole_Huber@uml.edu or phone: 978-934-4133.
The New England Junior Youth Wind Ensemble
The New England Junior Wind Ensemble is for junior high school students in grades 6-9. The ensemble meets on Monday and Wednesday evenings from 4:50 to 6 p.m. in Durgin Concert Hall. UMass Lowell's New England Junior Wind Ensemble (inaugural year 2007) brings students from the middle-school community together with college students from the UMass Lowell Music Department to rehearse and perform. This ensemble provides a unique opportunity for the participants -- young students are able to perform with those who will be the band directors of the future. Seating takes place in January; students are asked to prepare a piece to play in for a conductor's panel to ascertain seating order. The ensemble begins at the end of January and runs through April, with a finale concert taking place in May. Applications can be downloaded from the website. For more information contact the Artistic Director and Conductor by email: DebraNicole_Huber@uml.edu or phone: 978-934-4133.
The UMass Lowell String Project and Lowell Youth Orchestra
The UMass Lowell String Project, run by Executive Director Allyn McCourt was founded in 2001 by Prof. Kay G. Roberts. This program offers high-quality string training and creative music classes to Lowell Public School Students, targeting diverse, under-served neighborhoods.
Students are taught by UMass Lowell music majors, distinguished professors, and guest artists. Creative Sound Play introduces participants to music technology, improvisation, composition, and music from different cultures.
The UMass Lowell String Project provides a supportive, creative and educational environment where youth from diverse backgrounds learn to interact, exchange ideas, and make music together. We have created a musical community for parents, teachers, and students, and are an important cultural and social presence in Lowell, bringing free concerts to the community.
The UMass Lowell Youth Orchestra (LYO), founded in 2009 by Prof. Roberts, builds on the success of the UMass Lowell String Project, providing an outlet for young musicians interested in acquiring ensemble and performance experience. Under Executive Director Allyn McCourt, the LYO explores music from the traditional repertory as well as music reflective of Lowell's community of immigrants. Through music, the LYO and the UMass Lowell String Project contribute to the understanding of different cultures.
THE ECOSONIC PLAYGROUND PROJECT
The EcoSonic (Ecology/Sound) Playground Project™ (ESPP), headed by Music Department faculty member, Elissa Johnson-Green, aims to address equal access to arts education, adequate support for STEAM (science, technology, engineering, arts and mathematics) education while fostering sustainable practices. The ESPP focuses on working with children of all ages to design, build, and play large-scale, multi-player musical instrument structures made from reusable materials. It incorporates musical exploration, STEAM skills, and open creativity into an immersion learning curriculum. Focused, differentiated, and developmentally appropriate teaching practice inform all aspects of this project.