Tootfinder

"More than half of world’s bird species in decline, as leaders meet on extinction crisis"
#Birds #Animals

SpaceX-built spy satellites are helping the NRO greatly expand its satellite surveillance capabilities,
but the purpose of these signals is unknown.
https://www.npr.org/2025/10/17/nx-s1-5575254/spacex-starshield-starlink-signal
The sign…

Hilbert spaces admit no finitary discrete imaginaries
Ruiyuan Chen, Isabel Trindade
https://arxiv.org/abs/2509.11321 https://arxiv.org/pdf/2509.11321

Hilbert spaces admit no finitary discrete imaginaries
We prove that every functor from the category of Hilbert spaces and linear isometric embeddings to the category of sets which preserves directed colimits must be essentially constant on all infinite-dimensional spaces. In other words, every finitary set-valued imaginary over the theory of Hilbert spaces, in a broad signature-independent sense, must be essentially trivial. This extends a result and answers a question by Lieberman--Rosický--Vasey, who showed that no such functor on the supercate…

Number of wild bee species at risk of extinction in Europe doubles in 10 years https://www.theguardian.com/environment/2025/oct/11/number-of-wild-bee-species-at-risk-of-extinction-in-europe-doubles-in-10-years

fresh_webs: Freshwater stream webs
A set of 26 networks of trophic-level species interactions in streams in New Zealand, Maine and North Carolina. Networks include the identities of aquatic insect, algae and fish species and their trophic interactions. Excel and plain text adjacency matrices available; webs can be downloaded individually or as a group.
This network has 86 nodes and 353 edges.
Tags: Biological, Food web, Unweighted, Metadata

Geometric Constructions of Mod $p$ Cohomology Operations
Herng Yi Cheng
https://arxiv.org/abs/2510.12574 https://arxiv.org/pdf/2510.12574

Geometric Constructions of Mod $p$ Cohomology Operations
The Brown Representability Theorem implies that cohomology operations can be represented by continuous maps between Eilenberg-Maclane spaces. These Eilenberg-Maclane spaces have explicit geometric models as spaces of cycles on round spheres and spaces of relative cycles on unit disks, due to the Almgren Isomorphism Theorem. A. Nabutovsky asked what maps between spaces of cycles represent the Steenrod squares. In this work we answer this question by constructing maps with explicit formulas fro…

"First Nature Reserve to Record 10,000 Species in UK–Thanks to Moth That Looks Like a Wasp"
#UK #UnitedKingdom #Nature

First Nature Reserve to Record 10,000 Species in UK–Thanks to Moth That Looks Like a Wasp
The Wicken Fen nature reserve became the first in UK to record 10,000 species, after finding a unique moth that imitates a wasp.

nematode_mammal: Global nematode–mammal interactions (2018)
A global interaction web of interactions between nematodes and their host mammal species, extracted from the helminthR package and dataset. Nodes are annotated with species-level information.
This network has 30516 nodes and 146683 edges.
Tags: Biological, Food web, Unweighted, Metadata

foodweb_baywet: Florida cypress wetlands food web (1998)
Networks of carbon exchanges among species in the cypress wetlands of South Florida. One network covers the wet and the other the dry season. Each node represents a taxon (similar to a species), and a directed edge indicates that one taxon uses another as food.
This network has 128 nodes and 2106 edges.
Tags: Biological, Food web, Weighted

"Number of wild bee species at risk of extinction in Europe doubles in 10 years"
#Europe #Bees #Insects