Aging with my family: a grounded theory approach on the role of family when aging as foreign-born.

Background: Research indicates that it is the quality of the closest relationships in the mixture of social relations that matters most for older adults. For older foreign-born, especially those who migrate late in life, the family is often the only socioeconomical resource they can lean on. This study aims to explore how older foreign-born perceive the role of family as they age.

The Riddle of Ball Lightning: A Review.

One of the most intriguing and enduring scientific challenges is to find an explanation for ball lightning, the shining fireballs that sometimes appear near lightning strokes. Although many theoretical ideas have been proposed and much experimental work has been performed, there is not yet an accepted explanation of their amazing properties. They are surprisingly stable, lasting up to 10 s, even minutes in some rare cases.

Ball lightning as a force-free magnetic knot.

The stability of fireballs in a recent model of ball lightning is studied. It is shown that the balls shine while relaxing in an almost quiescent expansion, and that three effects contribute to their stability: (i) the formation in each one during a process of Taylor relaxation of a force-free magnetic field, a concept introduced in 1954 in order to explain the existence of large magnetic fields and currents in stable configurations of astrophysical plasmas; (ii) the so called Alfven conditions in magnetohydrodynamics; and (iii) the approximate conservation of the helicity integral. The force-free fields that appear are termed "knots" because their magnetic lines are closed and linked.