If a nucleus has a non-zero spin, it behaves as a small magnet. Therefore, in an external magnetic field, the nuclear magnetic moment vector precesses about the field direction but only certain orientations are allowed by quantum rules. Thus, for hydrogen (spin 1/2) there are two possible states in the presence of a field, each […]
The concept of crystal is very old, and it is strongly related to symmetries. Basically, a crystal is a system with a repeated pattern through space. For instance, in ice the water molecules form a hexagonal pattern, giving rise to many different macroscopic forms. But, can it happen that a system presents a pattern not […]
Preamble In the period 2015-2019, I was hired as a mathematician by a biology department in order to perform a research that eventually would become my doctoral thesis. This text is adapted from the last chapter of that thesis, “Cycles and interactions: A mathematician among biologists” (full text available here ). The symbiosis between mathematics […]
Strange exoplanet with oceans of lava discovered Astronomers have discovered an extremely hot Earth-sized planet hundreds of light-years away that has oceans made of lava, supersonic winds and rainfall made of rocks. K2-141b is very close to its star, and most of the planet is always in daylight because it is locked in place, facing […]
Adsorption commonly is understood as the reversible binding of molecules and atoms from the gaseous or liquid phase on surfaces, mostly of highly porous adsorbent media. In chemisorption a single layer of molecules, atoms or ions is attached to the adsorbent surface by chemical bonds; in physisorption only van der Waals forces are involved. Adsorption […]
In the past entry we introduced Plato’s model of the degrees of knowledge , ‘the simile of the line’, according to which the primordial difference between ‘science’ and ‘mere opinion’ is not so much about the ‘methods’ employed to reach one or the other (as will be assumed in modern times), but about the nature […]
Parkinson’s disease is characterized by neuronal loss in the brain’s substantia nigra region. What if another cell type, namely, astrocytes, could replace them? The work of two research groups recently published Zhou, H. et al. Cell 181, 590–603.e16 (2020). shows that, at least in mice, transforming astrocytes (a non-neuronal cell type in the brain) into […]
How long ago were Denisovans on the Tibetan Plateau? Denisovans were present on the Tibetan Plateau as far back as 100,000 years ago, according to mitochondrial DNA found in layers of cave sediment. Other sediment samples dating back approximately 60,000 to possibly 30,000 years ago could suggest the Denisovans were in the region when humans […]
Condensed matter • DIPC Advanced materials • Materials • Quantum physics
Topological materials have special universal properties, which are protected against perturbations. Such properties are theoretically described by topology, a branch of mathematics concerned with the properties of geometrical objects that are unchanged by continuous deformations. Topological materials behave like an ordinary insulator in the bulk but have conducting states on their boundaries, i.e., edges or […]
Populations are not static, and the geographic distribution of genetic diversity within and among populations is changing continuously. The drivers of genetic differentiation is one of the cornerstones in evolution, as genetic diversity is paramount for the ability of populations to adapt and persist in changing environments. The spatio-temporal changes in genetic diversity constantly taking […]