Extinction and recovery of mass flow through solid He4 samples

Simple model of recovery dynamics after mass extinction.

Biotic recoveries following mass extinctions are characterized by a complex set of dynamics, including the rebuilding of whole ecologies from low-diversity assemblages of survivors and opportunistic species. Three broad classes of diversity dynamics during recovery have been suggested: an immediate linear response, a logistic recovery, and a simple positive feedback pattern of species interacti...

Recovery from the most profound mass extinction of all time.

The end-Permian mass extinction, 251 million years (Myr) ago, was the most devastating ecological event of all time, and it was exacerbated by two earlier events at the beginning and end of the Guadalupian, 270 and 260 Myr ago. Ecosystems were destroyed worldwide, communities were restructured and organisms were left struggling to recover. Disaster taxa, such as Lystrosaurus, insinuated themsel...

HE4, CA-125, and cystic ovarian mass

To the editor: The recent publication on ‘HE4, CA-125, and cystic ovarian mass’ is very interesting [1]. Partheen et al. [1] concluded that HE4 did not outperform CA-125. Indeed, the use of two biomarkers might be expected for increased screening ability; however, the problem of the cost should be kept in mind. Incremental analysis on additional cost should be done. Based on the present report,...

Observation of mass transport through solid 4He

Universal temperature dependence, flux extinction, and the role of 3He impurities in superfluid mass transport through solid 4He.

The mass flux, F, carried by as-grown solid (4)He in the range 25.6-26.3 bar rises with falling temperature, and at a concentration-dependent temperature, T(d), the flux decreases sharply within a few mK. We study F as a function of (3)He impurity concentration, χ. We find that T(d) is an increasing function of increasing χ. At temperatures above T(d) the flux has a universal temperature depend...