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Did you like this article? Editorial Review This article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication. The Sassanian Empire (224-651 CE) was the greatest expression of Persian culture in the ancient world. It was consciously modeled on the earlier Achaemenid Empire (c. 550-330 BCE) which established Persian supremacy in the region and developed innovations in government, agriculture, ancient Persian art and architecture, and religion....

Did you like this article? Editorial Review This article has been reviewed for accuracy, reliability and adherence to academic standards prior to publication. The Tale of The Ship-Wrecked Sailor is a text dated to the Middle Kingdom of Egypt (2040-1782 BCE). It is a story of adventure whose purpose, besides entertainment, would have been to impress upon an audience how all one needed to be content in life was found in Egypt....

Floyd E. Romesberg received his doctorate from Cornell University in 1994, a degree granted for the study of salts called lithium dialkylamides. Synthetic chemists routinely use these compounds to remove protons from substances. Romesberg, the son of a chemist, spent his days looking at how these chemicals react and the rate at which the reactions took place. “It wasn’t so much that the project was interesting,” Romesberg says. “As a matter of fact, the project was pretty boring....

Among diseases of man and beast, anthrax stands as one of the oldest known and certainly one of the most storied. (It is thought to be what Homer meant by the “burning plague” in the Iliad.) Once a common killer of grazing animals, it was also a lethal occupational hazard for humans who worked with infected hides and livestock. Yet the cause of anthrax remained a menacing enigma until well into the 19th century, when an unassuming German country doctor entered the picture to help name it and tame it....

Listener Claire from Los Angeles writes that she and her partner have been together for two years, but recently she’s begun to worry the spark is gone. She’s interested in how love changes over time—are you supposed to feel like you’ve nested? Is that a good sign or a bad sign? So for this week’s episode, I set out to write about the stages of a relationship, but after digging through the research, I discovered that, unlike grief, with its denial, anger, bargaining, depression, and acceptance model, there’s no go-to stage theory for romantic love....

Climate change can influence how infectious diseases affect the world, particularly illnesses spread by vectors like mosquitoes. Now scientists have developed some understanding about how rainfall and temperature can influence malaria, dengue and West Nile virus infections as well as ways to combat them. Vector-borne diseases are among the most complex and vexing illnesses to manage, since so many elements are at play, like host resistance, the environment, urbanization and the pathogens themselves....

On March 11, 2011, a giant tsunami from the Pacific Ocean swept over the 10-meter sea wall surrounding six reactors at the Fukushima power plant on Japan’s east coast. The crashing water caused reactor cores to overheat and melt, and subsequent hydrogen explosions damaged three reactor buildings. Radiation spewed in every direction. The country shut down all of its more than 40 reactors, and investigations began into radiation exposure to tens of thousands of nearby residents, as well as to wildlife on land and sea....

It’s a gray, drizzly March day at Harvard University. Economist Michael Kremer is recalling his postcollegiate year, 1985, spent teaching high school in Kenya, contracting malaria, recovering and watching sick Kenyans fare worse than he. Melancholy enters his voice. “The burden of disease is just very clear,” he nearly sighs. “This is a terrible crisis. It seems vital to put the same sorts of entrepreneurial spirit and effort, and creativity, unleashed by the market sector”–he laughs dryly, as if in disbelief–“to work on these diseases as is being done for the diseases in rich countries....

(Credit:Photo illustration by James Martin/CNET)The U.S. government has demanded that major Internet companies divulge users’ stored passwords, according to two industry sources familiar with these orders, which represent an escalation in surveillance techniques that has not previously been disclosed.If the government is able to determine a person’s password, which is typically stored in encrypted form, the credential could be used to log in to an account to peruse confidential correspondence or even impersonate the user....

Gene therapy may finally be living up to its early promise. In the past six years the experimental procedure for placing healthy genes wherever they are needed in the body has restored sight in about 40 people with a hereditary form of blindness. Doctors have seen unprecedented results among another 120-plus patients with various cancers of the blood—several of whom remain free of malignancy three years after treatment. Researchers have also used gene therapy to enable a few men with hemophilia, a sometimes fatal bleeding disorder, to go longer without dangerous incidents or the need for high doses of clotting drugs....

Long sand dunes that ripple across Saturn’s moon Titan may have been there for thousands of years, results from NASA’s Cassini spacecraft suggest. Radar images of the dunes—the most detailed ever taken—reveal that the winds that rearrange the sand probably change direction as Titan’s orbit wobbles relative to the Sun. Those orbital variations are thought to alter which parts of the surface get the most sunlight, and the shape of the dunes reflect the resulting changes in weather patterns....

More than 20,000 radio antennas will soon connect over the Internet to scan largely unexplored radio frequencies, hunting for the first stars and galaxies and potentially signals of extraterrestrial intelligence. The Low Frequency Array (LOFAR) will consist of banks of antennas in 48 stations in the Netherlands and elsewhere in Europe, all hooked up by fiber optic cables. Signals from these stations will be combined using a supercomputer, transforming the array into “perhaps the most complex and versatile radio telescope ever attempted,” said Heino Falcke, chairman of the board for the International LOFAR Telescope....

Edited by Dava Sobel When we first detect the chirp of black holes colliding, she renders the press release into disappearing language: “Light splitter and union of instruments” (speak, interferometer) “Self-strengthened lights exploding” (speak, gamma rays). Such subtle “bird songs” are undone by gravitational waves, we are compelled to fix their fugitive features. In glaciers, nature deviates and also runs its course— its layers not quite memory, but more like artifice: snow’s structure, changed under so much weight the geometry of flakes collapses, heavy cold compressing air, deforming firn....

Perfluorinated and polyfluorinated alkyl substances, or PFASs, are considered indestructible chemicals. They are virtually nondegradable and accumulate in humans and the environment. Suspected health effects include asthma, cancer and changes in the reproductive organs. How to get rid of PFASs has been completely unclear until now—and the first approaches to destroying the resistant molecules are showing promising results. Heat is the key factor in breaking the carbon-fluorine bonds characteristic of this class of substances....

In many countries, people consider their salaries to be a closely guarded secret. But that makes them all the more curious about where they stand in their enterprise’s salary ordering. Let’s see if we can help them find out without their losing too much privacy. There are some number of employees whose salaries are known to be between x and y. You, as a trusted outsider, ask questions of the form “Who has salaries between s1 and s2 inclusive?...

The future looks warmer for many major cities, that’s clear—but perhaps you missed the part where it’s also forecast to look wetter. Scientific measurements show that the quantity of rainfall that fell on the Northern Hemisphere intensified in the second half of the 20th century. At least some of that increase can be attributed to anthropogenic climate change, according to a recent study. Economists, scientists and urban planners are increasingly documenting the growing risks of flood to city dwellers....

The creator of the popular online comic strip “Piled Higher and Deeper” has turned it into a feature film. The PhD Movie, which opened this week at a handful of US universities, will be screened at campuses worldwide in the coming months. Nature caught up with former robotics researcher turned cartoonist Jorge Cham to find out about his film. Why turn the comic strip into a movie? The spark was a spoof of a Lady Gaga video put together by some scientists in Texas....

Astronomers have finally found evidence that the rotation of young, whirling stars is slowed down by the planet-forming disks surrounding them. New data from NASAs Spitzer Space Telescope support the hypothesis that protoplanetary disks absorb some of a young stars angular momentum, which, if left unchecked, would cause the star to spin so fast it would fly apart under its own inertia. Scientists have believed for decades that planetary disks were probably responsible for slowing down spinning stars but until now observations did not clearly support the idea....

Key concepts Soil Composting Biology Microorganisms Recycling Environment Introduction Have you ever seen something labeled “biodegradable” or “compostable” and wondered what that means? A lot of different products—such as food containers, bags, packaging materials, and disposable spoons and forks—claim to be biodegradable or compostable, meaning they will eventually decompose naturally. But these objects are often made of different materials. Do they decompose differently? If so, which decomposes the fastest? In this science activity you will make your own indoor composter and investigate how well different biodegradable and compostable items decompose in it....

Cells in the body use hormones to communicate, for example controlling the fundamentals of human procreation through estrogen and testosterone. Similarly, bacteria colonies reach certain sizes and then individuals release chemicals to guide its overall development. Now researchers have tapped this cellular communication to create synthetic ecosystems replicating organisms that rely—or feed—on one another to survive, among other activities. The communication system could be used to produce pharmaceuticals or create synthetic prosthetic networks of cells to replace damaged natural networks in the human body, according to Martin Fussenegger, a biotechnologist at the Swiss Federal Institute of Technology in Zurich....