A lost city reveals the grandeur of medieval African civilization
Some of the world’s greatest cities during the Middle Ages were on the eastern coast of Africa. Their ornate stone domes and soaring walls, made with ocean corals and painted a brilliant white, were wonders to the traders that visited them from Asia, the Middle East, and Europe. They were the superpowers of the Swahili Coast, and they’ve long been misunderstood by archaeologists. It’s only recently that researchers outside Africa are beginning to appreciate their importance.
Throughout the Middle Ages, great civilizations ringed the Indian Ocean. From Egypt, people could travel the Red Sea to reach the ocean, then sail south to Africa, or continue east to the Arab world and India. Then, of course, one could travel over land on the famous Silk Road from India through central Asia and into China. In reality, few people ever made that journey. But many trade goods did, passed from hand to hand in cosmopolitan cities whose cultural diversity would have made places like New York and Sao Paolo look like monocultures.
Among those great medieval cities were places like Songo Mnara, a gorgeous and bustling Swahili city built on an island off the coast of Tanzania in the fourteenth century. At a time when European cities were getting wiped out by plagues and famines, Songo Mnara was thriving.
By coaxing light out of a single polymer molecule, researchers have made the world’s tiniest light-emitting diode.
This work is part of an interdisciplinary effort to make molecular scale electronic devices, which hold the potential for creating smaller but more powerful and energy-efficient computers. Guillaume Schull and his colleagues at the University of Strasbourg in France made the device with the conducting polymer polythiophene. They used a scanning tunneling microscope tip to locate and grab a single polythiophene molecule lying on a gold substrate. Then they pulled up the tip to suspend the molecule like a wire between the tip and the substrate.
The researchers report in the journalPhysical Review Letters that when they applied a voltage across the molecule, they were able to measure a nanoampere-scale current passing through it and to record light emitted from it.
Across cultures, people feel increased activity in different parts of the body as their mental state changes.
Many years ago, I was in Brussels, Belgium, spending a day interviewing with a series of prospective internships. I frantically rehearsed my resume bullet points—in English and French—as I tried to navigate my way through the unfamiliar city to make four different appointments. Just as I was mouthing sciences politiques to myself for the hundredth time on the metro, I realized that my hands and feet had begun to sweat uncontrollably. Soon, I was sliding around in my sensible, black “grown person” shoes as I dashed through the cobblestoned streets. Each new potential internship boss was met with a shaky bonjour and an outstretched hand that felt like a cold sponge. I hadn’t contracted some rare, waffle-induced glandular disorder. Emotions (anxiety, in my case) can activate nervous system, endocrine, and musculoskeletal responses, giving us tingles down the spine, flushed faces, and other classic physical manifestations. The question is, do certain sentiments generate similar responses in all of us? Do we all get glowy cheeks when we’re feeling amorous, for example, or butterflies when we’re feeling nervous? A new study by Finnish researchers published today in the Proceedings of the National Academies of Sciences, suggests that our emotions do indeed tend to influence our bodies in consistent ways. Across five experiments, 701 participants “were shown two silhouettes of bodies alongside emotional words, stories, movies, or facial expressions. They were asked to color the bodily regions whose activity they felt increasing or decreasing while viewing each stimulus.” The emotions were generated by having the subjects read short stories or watch movies. On a blank, computerized figurine, they were then asked to color in the areas of their body where sensations became stronger (the red and yellow) or weaker (blue and black) when they felt a certain way. (via Mapping How Emotions Manifest in the Body - Olga Khazan - The Atlantic)
A promising new treatment for diseases like Parkinson’s may lie in the use of neural stem cells. They could be transplanted into damaged brain tissue and grow to replace theneurons [nerve cells] lost to the ravenous disease. Unfortunately, there’s a problem with this plan; the new cells are reluctant to migrate away from their graft site. Scientists believe this is because newly transplanted cells are attracted to the existing brain cells nearby. On the right is a bright cluster of cells that have not migrated. However, if the chemicals that cause this attraction are blocked, the new cells are happy to move further away, into other brain areas (shown on the left by a spread of green branches). Enabling migration would allow neural stem cells to travel further afield and replace neurons that have been destroyed by neurological disease.
Written by Gaëlle Coullon
Image by Julia Ladewig, Philipp Koch and Oliver Brüstle
Maybe you’ve dreamt of being that man or woman who is so important as to compose speeches and letters simply by barking out declamations whilst an attentive assistant jots down your brilliant every word. Robot developer Franck Calzada has brought us one step closer. He’s created an assistant scribe for the common man in his new program in which a NAO robot can write any word.
At the moment, however, you’re going to need a lot of time – and patience – if you enlist NAO’s services. To say it’s deliberate in its writing is quite the understatement.
Calzada has himself spent a lot of time with NAO, teaching it to play games like catch, Hangman and the Statue Game. Now, with his ability to write any word it hears, NAO can actually get some work done. This isn’t the first time we’ve seen Nao write. And while it will definitely be some time before it begins replacing office workers, its penmanship has certainly improved. (via NAO Robot Has Learned To Write | Singularity Hub)