journal article
LitStream Collection
Salvatore Torquato
2009 Nature
doi: 10.1038/7257780apmid: N/A
A theory for packing the classic three-dimensional solids.
Home
doi: 10.1038/7257780apmid: N/A
A theory for packing the classic three-dimensional solids.
doi: 10.1038/7257780bpmid: N/A
The placoderms are a large group of primitive armoured fishes. Although wholly extinct, their enigmatic anatomy could hold clues to the evolution of the jawed vertebrates (gnathostomes), including ourselves. A new fossil discovery has clarified the mechanism of reproduction in Incisoscutum, an organism of particular interest as a member of the arthrodires, a large and important placoderm group. A well preserved fossil of an adult Incisoscutum ritcchiei female was recently found with embryos, evidence that fertilization was internal. The new fossil is of a male of the species, showing the presence of penis-like pelvic claspers similar to those found in fossil Ptyctodontida (a group of unarmoured placoderms) and in sharks.
doi: 10.1038/460781apmid: 19675599
Twenty years on, the success of the Montreal Protocol can help inform plans to mitigate climate change.
doi: 10.1038/460781bpmid: 19675600
There is every reason to be optimistic about the Obama administration's attitude towards science.
Showing 1 to 10 of 66 Articles