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Progress checking Zarankiewicz’s conjecture on the brick factory problem

Progress checking Zarankiewicz’s conjecture on the brick factory problem

Mathematics

By David Orden

A previous post presented the fascinating history of the brick factory problem, which wonders about the smallest possible number of rail crossings when connecting kilns and storage yards, which is mathematically modeled by the crossing number of the complete bipartite graph . Proposed by Paul Turán after the Second World War, the first advances on […]

MI weekly selection #42

MI weekly selection #42

Humanities & Social SciencesScienceTechnologyWeekly Selection

By César Tomé

19 elements to have atomic weights adjusted Aluminum, cadmium, gold and arsenic are among 19 elements that are having their atomic weights adjusted by the International Union of Pure and Applied Chemistry. More precise measurements are now available leading to the new weight calculations, which happens rarely. The atomic weight of nonmetal selenium hasn’t been […]

Quantum mechanics in biological systems (III): Magnetoception

Quantum mechanics in biological systems (III): Magnetoception

BiologyPhysics

By Daniel Moreno Andrés

Magnetoception, the fantastic ability to perceive magnetic fields. A skill though impossible for long. It was difficult to assume that a 0.5 Gauss Earth’s magnetic field (your fridge has one with 100 Gauss) could have some effect on living things. However, the magnetic field perception was supported since the very beginning by experimental observation and […]

The strong arm of a starfish

The strong arm of a starfish

Biology

By Rafael Medina

Symmetry is a major trait in the architecture of the vast majority of animals: if we exclude sponges, a typical animal body plan will show one or more planes of symmetry. Radial symmetry is considered the ancestral state for the Eumetazoa, with body plans such as the polyps and jellyfishes within the Cnidarians, usually with […]

MI weekly selection #40

MI weekly selection #40

Humanities & Social SciencesScienceTechnologyWeekly Selection

By César Tomé

Reprogrammed stem cells in mice could pave way to tissue regeneration Spanish scientists successfully forced mature cells into an embryonic-like state inside the bodies of living mice, creating so-called reprogrammed induced pluripotent stem cells. Transforming mature cells into stem-like cells “means turning back the clock when everything in the environment favors the opposite,” lead author […]