Sea floor swells and mantle plumes

Most of the intraplate oceanic hot spots are located on the crest of broad topographic swells in the sea floor. These swells have Gaussian shaped profiles, with up to 1.6 km of relief and half widths of 200 to 300 km. Swells are accompanied by positive geoid height anomalies with amplitudes of 6 to 8 m. In the Atlantic and Pacific basins swells cover an area equal to 10% of the Earth's surface. Next to boundary layer contraction, swells are the most important cause of uplift and subsidence in oceanic lithosphere. Calculation of buoyancy supported topography and geoid height were combined with uplift data from laboratory experiments to assess whether sea floor swell can be produced by mantle plumes. The critical constraints are: (1) swell topographic profiles; (2) geoid height/topographic height ratios; and (3) uplift rates, estimated to be 0.2 km/ma

Experiences of mental illness, treatment and recovery in schizophrenia. An existential-phenomenological exploration

This study explores in depth the narratives and experience of recovery from a convenience sample of seven participants with a schizophrenia diagnosis, but now remitted (Andreasen et al, 2005). Three lifeworlds (phases) emerged using hermeneutic phenomenology: (A) Losing existential grounding; (B) Being-within-the-system (i.e. hospitalised); and (C) Outside schizophrenia. Outside has a double meaning as it both emerges from the narratives and also is an important base for existential exploration: what else needs to happen except psychiatry? Each lifeworld had a different meaning and different behaviours connected to it. Two necessary transitions were identified: First, accepting help; and second, an existential construction or re- construction depending on where in your life course you become affected. Psychotherapy was useful, but not necessary for remission and recovery

Sampling arbitrary photon-added or photon-subtracted squeezed states is in the same complexity class as boson sampling

Boson sampling is a simple model for non-universal linear optics quantum computing using far fewer physical resources than universal schemes. An input state comprising vacuum and single photon states is fed through a Haar-random linear optics network and sampled at the output using coincidence photodetection. This problem is strongly believed to be classically hard to simulate. We show that an analogous procedure implements the same problem, using photon-added or -subtracted squeezed vacuum states (with arbitrary squeezing), where sampling at the output is performed via parity measurements. The equivalence is exact and independent of the squeezing parameter, and hence provides an entire class of new quantum states of light in the same complexity class as boson sampling.Comment: 5 pages, 2 figure