If you care about the environment, you probably have become familiar with the phrase 'food miles' - along with production methods, it has become a key factor in what environmentally conscious people do to get quality food with less impact on the ecosystem.

But they may be negating it, according to new research by the University of Exeter (UK) p ublished in the journal Food Policy.   Shopping locally may not be as good for the environment as having food delivered -  on average, lower carbon emissions result even from having food delivered right to your house than driving to a local farm.

Most animals, like humans, have separate sexes.  We are born, live out our lives and reproduce as one sex or the other, but some animals live as one sex in part of their lifetime and then switch to the other sex, a phenomenon called sequential hermaphroditism.   Yale scientists believe the bigger puzzle is why the phenomenon is so rare, since their analysis shows the biological “costs” of changing sexes rarely outweigh the advantages.

This process is even evolutionarily favored, they say, so its rarity cannot be explained by an analysis of the biological costs vs benefits.

Sliced light is how we communicate now. Millions of phone calls and cable television shows per second are dispatched through fibers in the form of digital zeros and ones formed by chopping laser pulses into bits. This slicing and dicing is generally done with an electro-optic modulator, a device for allowing an electric signal to switch a laser beam on and off at high speeds (the equivalent of putting your hand in front of a flashlight). Reading that fast data stream with a compact and reliable receiver is another matter. A new error-free speed-reading record using a compact ultra-fast component—640 Gbits/second (Gbps, or billion bits per second)—has now been established by a collaboration of scientists from Denmark and Australia.

Whenever humans create a new antibiotic, deadly bacteria can counter it by turning into new, indestructible super-bugs. That's why bacterial infection is the number one killer in hospitals today. But new research from Tel Aviv University may give drug developers the upper hand in outsmarting bacteria once and for all. 

The secret weapon against a colony of bacteria may be to stress it with its own protection system, which forces it to reduce its population through ... cannibalism.

If you're a female science teacher, male students tend to underrate you.   Even worse, if you are a female science teacher in physics, both male and female students underrate you,  according to a study of 18,000 biology, chemistry and physics students.

Are female science teachers just worse than males and instead got the jobs because of  social engineering?   No, male and female teachers are equally effective at preparing their students for college, say researchers at Clemson University, the University of Virginia and Harvard University, it's instead gender bias.  Their findings appear in Science Education online in the research paper, "Unraveling Bias from Student Evaluations of their High School Science Teachers."

Picture a tree in the forest. The tree "inhales" carbon dioxide from the atmosphere, transforming that greenhouse gas into the building materials and energy it needs to grow its branches and leaves. 

By removing carbon dioxide from the atmosphere, the tree serves as an indispensable "sink," or warehouse, for carbon that, in tandem with Earth's other trees, plants and the ocean, helps reduce rising levels of carbon dioxide in the air that contribute to global warming.