Tootfinder

Sensor Tower: daily US users of PDD Holdings' Temu fell by 58% in May; the US closed the "de minimis" loophole on May 2, and Temu then slashed its ad spending (Reuters)
https://www.reuters.com/business/retail-co

BILL GATE

A while ago, I've followed the example given by #Fedora and unbundled ensurepip wheels from #Python in #Gentoo (just checked — "a while ago" was 3 years ago). This had the important advantage that it enabled us to update these wheels along with the actual pip and setuptools packages, meaning new virtual environments would get fresh versions rather than whatever CPython happened to bundle at the time of release.
I had considered using our system packages to prepare these wheels, but since we were already unbundling dependencies back then, that couldn't work. So I just went with fetching upstream wheels from PyPI. Why not build them from source instead? Well, besides feeling unnecessary (it's not like the PyPI wheels are actually binary packages), we probably didn't have the right kind of eclass support for that at the time.
Inspired by @…, today I've tried preparing new revisions of ensurepip packages that actually do build everything from source. So what changed, and why should building from source matter now? Firstly, as part of the wheel reuse patches, we do have a reasonably clean architecture to grab the wheels created as part of the PEP517 build. Secondly, since we're unbundling dependencies from pip and setuptools, we're effectively testing different packages than these installed as ensurepip wheels — and so it would be meaningful to test both variants. Thirdly, building from source is going to make patching easier, and at the very least enable user patching.
While at it, I've refreshed the test suite runs in all three regular packages (pip, setuptools and wheel — we need an "ensurepip" wheel for the last because of test suites). And of course, I hit some test failures in testing the versions with bundled dependencies, and I've discovered a random bug in #PyPy.
https://github.com/gentoo/gentoo/pull/42882 (yes, we haven't moved yet)
https://github.com/pypy/pypy/issues/5306

Here's a more positive challenge for the "AI scientists": reproduce a paper. From the PDF alone, implement and re-run the experiments as written, filling in the gaps as necessary and get the same results.
That's a lot more meaningful than passing peer review and it would actually be quite useful to automate. It could become a required check on any accepted paper.

Scalable Etch-Free Transfer of Low-Dimensional Materials from Metal Films to Diverse Substrates
Kentaro Yumigeta (Department of Materials Science & Engineering, University of Arizona, Tucson, Arizona, USA), Muhammed Yusufoglu (Department of Materials Science & Engineering, University of Arizona, Tucson, Arizona, USA), Mamun Sarker (Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska, USA), Rishi Raj (Department of Chemical Engineering and Materials Scienc…

Scalable Etch-Free Transfer of Low-Dimensional Materials from Metal Films to Diverse Substrates
Low-dimensional materials hold great promises for exploring emergent physical phenomena, nanoelectronics, and quantum technologies. Their synthesis often depends on catalytic metal films, from which the synthesized materials must be transferred to insulating substrates to enable device functionality and minimize interfacial interactions during quantum investigations. Conventional transfer methods, such as chemical etching or electrochemical delamination, degrade material quality, limit scalabil…

Calamus 14 Not heat flames up and consumes
A declaration of love, eroticism mixed with nature imagery. Something of a theme in Calamus! It didn't really grab me though, I think because so many of the lines start with negations and it distances me from the meaning.
The sexy line here:
the flames of me, consuming, burning for his love whom I love!
I also like the imagery of seeds wafted in the wind, then heading to "my Soul is borne through the open air".
This musical performance by the Erato Ensemble is a nice interpretation.

Primordial Black Holes as Coma Cluster Dark Matter and the Unresolved {\gamma}-Ray Background
Jeremy Mould, Bhashin Thakore
https://arxiv.org/abs/2507.01421

Primordial Black Holes as Coma Cluster Dark Matter and the Unresolved γ-Ray Background
If 0.1% of the dark matter in the Coma cluster is constituted by primordial black holes (PBHs) with masses ranging from 10^-19 to 10^-17 solar masses, then the observed GeV γ-ray emission from the cluster could potentially be attributed to Hawking radiation. The emitted spectrum is inversely proportional to the black hole's mass, meaning lighter PBHs radiate at higher energies, potentially falling within the GeV range. If 0.1% of the Coma cluster's dark matter is PBH in this mass range, a fit …

Comparing Optimization Algorithms Through the Lens of Search Behavior Analysis
Gjorgjina Cenikj, Ga\v{s}per Petelin, Tome Eftimov
https://arxiv.org/abs/2507.01668

Comparing Optimization Algorithms Through the Lens of Search Behavior Analysis
The field of numerical optimization has recently seen a surge in the development of "novel" metaheuristic algorithms, inspired by metaphors derived from natural or human-made processes, which have been widely criticized for obscuring meaningful innovations and failing to distinguish themselves from existing approaches. Aiming to address these concerns, we investigate the applicability of statistical tests for comparing algorithms based on their search behavior. We utilize the cross-match statis…

Existence of normalized solutions to nonlinear Schr\"odinger equations on lattice graphs
Zhentao He, Chao Ji, Yifan Tao
https://arxiv.org/abs/2507.01591

Existence of normalized solutions to nonlinear Schrödinger equations on lattice graphs
In this paper, using a discrete Schwarz rearrangement on lattice graphs developed in \cite{DSR}, we study the existence of global minimizers for the following functional $I:H^1\left(\mathbb{Z}^N\right)\to \R$, $$I(u)=\frac{1}{2} \int_{\mathbb{Z}^N}|\nabla u|^2 \,dμ-\int_{\mathbb{Z}^N} F(u)\, dμ,$$ constrained on $S_m:=\left\{u \in H^1\left(\mathbb{Z}^N\right) \mid\|u\|_{\ell^2\left(\mathbb{Z}^N\right)}^2=m\right\}$, where $N \geq 2$, $m>0$ is prescribed, $f \in C(\mathbb{R…

Calamus 43 O you whom I often
A short and sweet love poem, Whitman at his most writerly. The spare and simple words have a light musicality that's often missing from his more didactic blank verse.
The literal meaning is Whitman telling someone how his very presence inspires feelings of love. It's so short and precise I'm just going to quote the whole poem.
O you whom I often and silently come where you are, that I may be with you,
As I walk by your side, or sit near, or remain in the same room with you,
Little you know the subtle electric fire that for your sake is playing within me.
I love the lack of action. Whitman simply wants to sit in the same room as his beloved, a quiet devotion I appreciate. And that phrase "subtle electric fire". Electric had a different meaning in pre-Edison America but it works both ways.
Mostly this poem is just a lovely mood.
(The linked video and commentary are more than usually good.)