Tootfinder

Another awesome day in #Caledon, mix of sun & cloud and 7°C. We had a special guest on our hike today - this mare came galloping across the field to see us, with particular interest in Harley. Harley heard the hoof beats and ran into the woods. Not the bravest dog we've ever owned.
#DogsOfMastadon

In which I brush up and release (0.5.0) the “topfew” program I built back in 2021/22 and have been neglecting, but noticed that I was using it all the time so maybe others will too: https://www.tbray.org/ongoing/When/202x/2024/04/12/Topfew-release

Topfew Release 0.5

The Origin of Young Stellar Populations in NGC 1783: Accretion of External Stars
Li Wang, Licai Deng, Xiaoying Pang, Long Wang, Richard de Grijs, Antonino P. Milone, Chengyuan Li
https://arxiv.org/abs/2404.08047

The Origin of Young Stellar Populations in NGC 1783: Accretion of External Stars
The presence of young stellar populations in the Large Magellanic Cloud cluster NGC 1783 has caught significant attention, with suggestions ranging from it being a genuine secondary stellar generation to a population of blue straggler stars or simply contamination from background stars. Thanks to multi-epoch observations with the Hubble Space Telescope, proper motions for stars within the field of NGC 1783 have been derived, thus allowing accurate cluster membership determination. Here, we repo…

This https://arxiv.org/abs/2403.07659 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_mat…

The power operation in the Galois cohomology of a reductive group over a number field
For a connected reductive group $G$ over a local or global field $K$, we define a *diamond* (or *power*) operation $$(ξ, n)\mapsto ξ^{\Diamond n}\, \colon\ H^1(K,G)\times {\mathbb Z}\to H^1(K,G)$$ of raising to power $n$ in the Galois cohomology pointed set (this operation is new when $K$ is a number field). We show that this operation has many functorial properties. When $G$ is a torus, the ponted set $H^1(K,G)$ has a natural group structure, and our new operation coincides with the usual po…

Here's their press release from this morning:
Alt text here instead of in images due to length:
NEWS RELEASE Embargoed until April 24, 7:00am PST
Divest From Death USA
Media Contact: Media Liaisons, USC Divest From Death Coalition USCSolidarityOccupation@protonmail.com
USC Divest From Death Coalition to Begin Gaza Solidarity Occupation in University of
Southern California Campus
LOS ANGELES. (April 24, 2023) — USC Divest From Death Coalition today announced theit occupation of USC's Alumni Park, where the increasingly controversial 2024 Commencement is currently set to take place. The students taking part in the Gaza Solidarity Occupation are planning to occupy USC until their demands are met. The coalition joins other students groups across the country in the National Students for Justice in Palestine's "Popular University for Gaza," a coordinated mass movement of students, faculty and staff that disrupts universities, creating climates that push universities to answer community and international calls for full divestment from the Zionist entity, and all of the industries that sustain it.
1. End War Profiteering and Investment in Genocide. USC must fully disclose and divest its finances and endowment from companies and institutions that profit from Israeli apartheid, genocide, and occupation in Palestine, including the US Military and weapons manufacturing. USC must comumit to accountability through full transparency of their financial investments.
2. Complete Academic Boycott of Israel. USC must end its study abroad programs at Hebrew University's Rothenberg International School and Reichman University and sever all academic ties and research cooperation with Israeli universities.
3. Protect free speech on campus and provide full amnesty to all students, staff, and faculty disciplined, penalized, or fired for their pro-Palestine ackivism. USC must abide by their self- proclaimed Diversity, Equity, and Inclusion values and implement material policies protecting the safety of its marginalized students.
4. Stop the Displacement, from South Central to Palestine. No land grabs, whether in South Central, Tongva territory, or Palestine. Cease expansion, provide reparations, and support housing for low-income South Central residents. No development by USC without genuine community control.
5. No Policing on Campus. End the targeted repression and harassment of Black, Brown, and Palestinian students and their allies on and off campus, including through university disciplinary processes. Defund the Department of Public Safety and disclose and sever all ties with the LAPD.
6. End the Silence on the Genocide in Palestine. Release a public statement calling for an immediate, permanent ceasefire in Gaza, denouncing the ongoing genocidal campaign against the Palestinian people, and call on government officials o do so too.
"I'm participating in the Gaza Solidarity Occupation at USC to highlight and amplify the anti- zionist Jewish voice at USC and be in solidarity with the Palestinian fight for liberation," says a student organizer from USC's chapter of Jewish Voices for Palestine (JVP). "JVP USC feels our voice is especially important right now as many people at USC and across the country are equating zionism and Judaism, but we are here to say they are not the same! We stand by our belief of free speech, resistance to oppressive systems and solidarity with our valedictorian Asna and all other college campuses where pro-Palestine voices have been silenced."
The USC Divest From Death Coalition establishes the occupation mo st fundamentally in solidarity with the people of Palestine as they resist genocide and continue in their struggle for liberation. The occupation is also in resistance to attempts by USC and other universities to suppress the student movement for Palestine on its campuses, in resistance to the silencing of students that criticize the state of Israel, in resistance to the university administrators and boards of trustees who profit off the genocide of Palestinians; The students taking part are firm in their commitment to speaking out against the university's complicity in the genocide of the Palestinian people.
"USC's funding of the ongoing genocide perpetuated by the zionist entity is reflective of maintaining imperialist interests abroad, as well as solidifying the shared ideology of amerikan and zionist institutions in preserving racialized oppression," says a student organizer of the Gaza Solidarity Occupation. "To not stand in opposition to the expressly racist violence here and abroad is to ignore the calls for solidarity demanded by the majority of the world. USC acts in accordance with these oppressions, and to call against this is to recognize both the inhumanity of these systems and our own humanity in opposing them."
We have chosen to use the word "occupation” instead of "encampment" to draw attention to USC as an occupying force on unceded Gabrieleno/Tongva land, an occupying force in South Central through its expansion into, gentrification of, and destruction of the existing community, and as a complicit power in Israeli occupation of Palestine.
About USC Divest From Death
In joining the national "Cut Ties with Genocide: Divest from Death" campaign, USC Divest From Death pushes our institutions to divest from companies complicit in the genocide of Palestinians, in all its iterations, alongside thousands of campuses. The coalition's push for the advancement of the key demand points on campus is the first steps towards the liberation of all people by ending the complicity of the University of Southern California in the violence enacted on our communities. Through the intentional act of coalition building, the students of USC realize that we are part of an interconnected fight for freedom taking place on campus, in our communities and homelands. We envision campuses free from militarism, occupation, and war through the implementation of divestment at USC
About Students for Justice in Palestine (SJP)
The student movement for the liberation of Palestine first began in the 1950s through the formation of the General Union of Palestinian Students (GUPS). From the U.S. to Palestine, GUPS chapters galvanized thousands of students towards a liberated Palestine. The 90s” wave of corrupt politicians and faulty deals changed the liberation movement as we knew it and many institutions, including the student movement, collapsed. In the absence of a Palestinian student movement, organizations such as Students for Justice in Palestine emerged across occupied Turtle Island (U.S. and Canada) as a way to educate, advocate, and mobilize in support for Palestinian liberation. Nearly two decades after the formation of the first Students for Justice in Palestine, the movement for Palestine has taken colleges and universities across North America by storm. With over 200 campus Palestine solidarity organizations across the continent, students have been leaders in uplifting demands for freedom, Justice, and equality for the Palestinian people.

Advancing aortic stenosis assessment: validation of fluid-structure interaction models against 4D flow MRI data
Alberto Zingaro, Irmantas Burba, David Oks, Mauro Fontana, Crist\'obal Samaniego, Micha Bischofberger, Bart de Boeck, Andre Douverny, \"Ozge Karakas, Stefan Toggweiler, Dabit Arzamendi-Aizpurua, Utku G\"ulan, Mariano V\'azquez

Advancing aortic stenosis assessment: validation of fluid-structure interaction models against 4D flow MRI data
Systematic in vivo validations of computational models of the aortic valve remain scarce, despite successful validation against in vitro data. Utilizing a combination of computed tomography and 4D flow magnetic resonance imaging data, we developed patient-specific fluid-structure interaction models of the aortic valve immersed in the aorta for five patients in the pre-transcatheter aortic valve replacement configuration. Incorporating also an in vitro setup of the valve, our computational model…

Modules over linear spaces admitting a multiplicative basis
Antonio J. Calder\'on, Francisco J. Navarro Izquierdo, Jos\'e M. S\'anchez
https://arxiv.org/abs/2403.08779

Modules over linear spaces admitting a multiplicative basis
We study the structure of certain modules $V$ over linear spaces $W$ with restrictions neither on the dimensions nor on the base field $\mathbb F$. A basis $\mathfrak B = \{v_i\}_{i\in I}$ of $V$ is called multiplicative respect to the basis $\mathfrak B' = \{w_j\}_{j \in J}$ of $W$ if for any $i \in I, j \in J$ we have either $v_iw_j = 0$ or $0 \neq v_iw_j \in \mathbb Fv_k$ for some $k \in I$. We show that if $V$ admits a multiplicative basis then it decomposes as the direct sum $V=\bigoplus_k…

In which I brush up and release (0.5.0) the “topfew” program I built back in 2021/22 and have been neglecting, but noticed that I was using it all the time so maybe others will too: https://www.tbray.org/ongoing/When/202x/2024/04/12/Topfew-release

Topfew Release 0.5

The power operation in the Galois cohomology of a reductive group over a number field
Mikhail Borovoi, Zinovy Reichstein
https://arxiv.org/abs/2403.07659 h…

The power operation in the Galois cohomology of a reductive group over a number field
For a connected reductive group $G$ over a local or global field $K$, we define a *diamond* (or *power*) operation $$(ξ, n)\mapsto ξ^{\Diamond n}\, \colon\ H^1(K,G)\times {\mathbb Z}\to H^1(K,G)$$ of raising to power $n$ in the Galois cohomology pointed set (this operation is new when $K$ is a number field). We show that this operation has many functorial properties. When $G$ is a torus, the ponted set $H^1(K,G)$ has a natural group structure, and our new operation coincides with the usual po…