Lifeboat Foundation

Cities change as they grow — not only by adding area or population but also in a variety of other ways, from the length and width of their roads to economic growth to the distribution of elementary schools. Social scientists often clash over the best way to measure change as a city swells. Traditionally, they’ve taken a cross-sectional approach, which means collecting data on a large number of cities of diverse sizes at the same moment in time. More recently, some researcher…

New work reconciles divergent methods used to analyze the scaling behavior of cities.

A region beneath the rough waters of the North Sea, known as Doggerland, holds archaeological clues to the past. Watch how researchers are using advances in mapping and leads from dredging sites to piece together the history of this vanished landscape.

Read the story: https://www.sciencemag.org/news/2020/01/relics-washed-beache…-north-sea

Continue reading “Maps of a now-submerged land help reconstruct the lives of ancient Europeans” »

This is the first-ever 3D-printed human heart model using human cells #ValentinesDay

A theoretical study reveals that, in certain situations, some materials might heat up more quickly after first being cooled.

Still, the fact that many labs worldwide are capable of printing viruses is worrisome.

A few years ago, for instance, Canadian researchers alarmed the scientific community when they assembled synthetic horsepox in a lab — a virus closely related to smallpox, which killed hundreds of millions before researchers developed a vaccine.

The same technique, the researchers said at the time, could be be used to bring back smallpox, giving terrorists tools to set off a deadly pandemic.

Grim details emerge.

Meet Surena IV, an adult-size humanoid built by University of Tehran roboticists.

A little over a decade ago, researchers at the University of Tehran introduced a rudimentary humanoid robot called Surena. An improved model capable of walking, Surena II, was announced not long after, followed by the more capable Surena III in 2015.

Continue reading “Iran Unveils Its Most Advanced Humanoid Robot Yet” »

When Betelgeuse explodes, there’s nothing stopping another civilization from surfing the supernova with a light sail.

By Brad Bergan

Nontrivial band topology can combine with magnetic order in a magnetic topological insulator to produce exotic states of matter such as quantum anomalous Hall (QAH) insulators and axion insulators. An aim of condensed matter physics is to find new materials with useful properties and apply quantum mechanics to study them. The field has allowed physicists to better understand the uses of magnets for hard disk data storage, computer displays and other technologies. The recent discovery of topological insulators have attracted broad interest and researchers predict that the interplay between ferromagnetism and the topological insulator state can realize a range of exotic quantum magnetic phenomena of interest in fundamental physics and device applications.

In a new report, Yujun Deng and a research team at the departments of physics and quantum matter physics in China, probed quantum transport in a thin flake MnBi₂Te₄ topological insulator, with intrinsic magnetic order. The ferromagnetic layers coupled anti-parallelly to each other in the atomically thin MnBi₂Te₄ layered van der Waals crystal. However, the sample became ferromagnetic when it contained an odd number of septuple layers. The research team observed the zero-field QAH effect in a five-septuple-layer specimen at 1.4 Kelvin. The results established MnBi₂Te₄ as an ideal platform to explore exotic topological phenomena with spontaneously broken time-reversal symmetry. The work is now published on Science.

Topological materials distinctly contain topologically protected quantum states that are robust against local distresses. For instance, in a topological insulator (TI) such as bismuth telluride (Bi₂Te₃), the bulk band topology can guarantee the existence of two-dimensional (2-D) surface states with gapless Dirac dispersion. By introducing magnetism into the initially time-reversal invariant topological insulators (TIs), scientists can induce profound changes in their electronic structure. For example, to experimentally observe the QAH effect in chromium-doped (Bi, Sb)₂Te₃, physicists had to precisely control the ratio of multiple elements in a non-stoichiometric material. Fine-tuning the material required reconciling conflicting demands and therefore, researchers had to precisely quantize the anomalous Hall effect only at temperatures up to T = 2 K, far below the Curie temperature and exchange gap in the material.