The pressure dependence of the hidden order phase of the heavy fermion superconductor URu2Si2 has been a subject of intense research since shortly after the discovery of the compound decades ago. Applied pressure increases the critical temperature of the paramagnetic / hidden order transition and brings about a transition to long-range antiferromagnetism. The reported pressures and temperatures of these phase boundaries vary between studies: 4 – 7 kbar at low temperature and 12 – 15 kbar at high temperature. We review experimental evidence that the measured values of pressure and temperature are very sensitive to the chosen pressure transmitting medium. Recent x-ray diffraction measurements suggest that the relative position of the silicon atom in the unit cell is changing as a function of pressure. Recent neutron diffraction measurements show that the zero-temperature limit of the hidden order / antiferromagnetic transition occurs at pressures greater than 7.5 kbar.

Scientific and commercial collecting have documented high levels of abundance among several species of marine snakes. Estimates of first-year mortality in populations of marine snakes range from 40 to 90%. The primary cause of this mortality is unknown. Storms, currents, sun exposure, dehydration and fire are abiotic factors that may control populations of marine and amphibious snakes. Disease, malnutrition and predation are biotic factors known to affect populations. In the literature there are isolated reports of predation by marine mammals, birds of prey, fish and invertebrates. Sharks in Australian waters are known to be predators on sea snakes. Our studies show that in the estuaries, intertidal mangrove creeks and mud flats of southeast Asia decapod crustaceans are important snake predators. Microhabitat overlap, exoskeleton armour and a respiratory advantage in an underwater standoff argue for their potential as potent predators. Field observations, a survey of crab stomach contents and encounters between snakes and crabs under laboratory conditions support this hypothesis. –