Mass measurements of very neutron-deficient Mo and Tc isotopes and their impact on rp process nucleosynthesis.

The masses of ten proton-rich nuclides, including the N=Z+1 nuclides 85Mo and 87Tc, were measured with the Penning trap mass spectrometer SHIPTRAP. Compared to the Atomic Mass Evaluation 2003 a systematic shift of the mass surface by up to 1.6 MeV is observed causing significant abundance changes of the ashes of astrophysical x-ray bursts. Surprisingly low α separation energies for neutron-deficient Mo and Tc are found, making the formation of a ZrNb cycle in the rp process possible. Such a cycle would impose an upper temperature limit for the synthesis of elements beyond Nb in the rp process.

Direct mass measurements above uranium bridge the gap to the island of stability.

The mass of an atom incorporates all its constituents and their interactions. The difference between the mass of an atom and the sum of its building blocks (the binding energy) is a manifestation of Einstein's famous relation E = mc(2). The binding energy determines the energy available for nuclear reactions and decays (and thus the creation of elements by stellar nucleosynthesis), and holds the key to the fundamental question of how heavy the elements can be. Superheavy elements have been observed in challenging production experiments, but our present knowledge of the binding energy of these nuclides is based only on the detection of their decay products. The reconstruction from extended decay chains introduces uncertainties that render the interpretation difficult. Here we report direct mass measurements of trans-uranium nuclides. Located at the farthest tip of the actinide species on the proton number-neutron number diagram, these nuclides represent the gateway to the predicted island of stability. In particular, we have determined the mass values of (252-254)No (atomic number 102) with the Penning trap mass spectrometer SHIPTRAP. The uncertainties are of the order of 10 keV/c(2) (representing a relative precision of 0.05 p.p.m.), despite minute production rates of less than one atom per second. Our experiments advance direct mass measurements by ten atomic numbers with no loss in accuracy, and provide reliable anchor points en route to the island of stability.

Nurses and strikes: a perspective from the United States.

In the United States, there has been a continuous debate between those who favour collective bargaining for nurses and those who believe it is not professional. Likewise, the controversy over whether nurses should strike has been longstanding and continues today. Those who oppose the idea of nurses striking often state that they are abandoning their patients, and that it is not ethical, even though federal legislation requires a 10-day strike notice so that management can make patient care arrangements. The American Nurses Association (ANA) has supported the right of nurses to strike, as a last resort and after careful consideration of every factor. This support has divided the membership of ANA and the nursing profession, even though the strikes have been used sparingly and effectively by nurses in this country; and so the debate continues.