Topological insulators are electronic materials that have a bulk band gap like an ordinary insulator but have conducting states on their edge or surface. The conducting surface is not what makes topological insulators unique, but the fact that it is protected due to the combination of spin-orbit interactions and time-reversal symmetry. Researchers are chasing efficient […]
Reference contains the following statement: “Ashtekar’s formulation of general relativity taught us to think of gravitational theories as theories of connections, on a bare manifold with no metric structure. […] The idea that general relativity has its deepest formulation as a connection theory suggested immediately a new approach to the unification of general relativity with […]
For centuries, metals were employed in optical applications only as mirrors and gratings. New vistas opened up in the late 1970s and early 1980s with the discovery of surface-enhanced Raman scattering and the use of surface plasmon (collective electronic oscillations at the surface of metals) resonances for sensing. However, it was not until the 1990s […]
When we talk about nucleic acids we generally think of DNA and RNA that code for proteins, and when we talk about brain cells we tend to think of neurons and their nerve impulse transmission. However, it is not news that the functions of both non-coding genetic material and non-transmitting cells in the brain are […]
Over geologic time scales, seawater transforms the basalt of the ocean floor by chemical attack. At the end of this alteration process, the basalt turns partly into clays and partly into dissolved salts in sea water. Lithium, a chemical element initially contained in basalt, will then be distributed between clay and seawater. This separation has […]
Syphilis is a sexually transmitted disease caused by a spirochete, a bacterium, Treponema pallidum subspecies pallidum . The main route of infection is by sexual contact but is also transmitted from the mother to the newborn in what is known as congenital syphilis. If syphilis is left untreated for years the treponema may invade the […]
The idea that certain natural products such as rubber are composed of giant molecules, or polymers, consisting of many repeating units linked by covalent bonds arose largely from the work of the German chemist Hermann Staudinger (1881–1965) in the early 1920s. He convinced skeptical chemists of this idea partly by linking small organic molecules (monomers) […]
After all those big discoveries of the latest years (LIGO’s gravitational waves, or NASA’s TRAPPIST system, for example) I felt the need to explain how normal everyday astrophysics is dealt with. To explain the little things behind any discovery, and the scientific journey between seeing something odd in the sky and explaining it with science […]
There are compounds, called isomers, that have the same molecular formulae but different molecular structures or different arrangements of atoms in space. In the so-called cis-trans isomerism, isomers have different positions of groups or specific atoms with respect to a double bond, a ring or a central atom. For example, the numbers in the name […]
Juvenile delinquency is a serious and common problem but not hopeless: it has been on the decline for a number of years, yet, juvenile courts continue to assess millions of cases per year. There are times when this subject seems hopeless such as when we read about a horrendous crime committed by a minor. The […]