Spectroscopy of the 1S0−3P0^1S_0-{}^3P_0 Clock Transition of 87^{87}Sr in an Optical Lattice

We report on the spectroscopy of the $5s^2 {}^1S_0 (F=9/2) \to 5s5p {}^3P_0 (F=9/2)$ clock transition of ${}^{87}{\rm Sr}$ atoms (natural linewidth of 1 mHz) trapped in a one-dimensional optical lattice. Recoilless transitions with a linewidth of 0.7 kHz as well as the vibrational structure of the lattice potential were observed. By investigating the wavelength dependence of the carrier linewidth, we determined the magic wavelength, where the light shift in the clock transition vanishes, to be $813.5\pm0.9$ nm.Comment: 4 pages, 4 figures, submitted to Phys. Rev. Lett. (09/May/2003

The Right to Life of Potential Persons

The law accords an individual the right to sue for damages sustained in utero when these damages are the result of what would otherwise be described as criminally negligent treatment. Recent court actions involving children subjected to the influence of thalidomide during certain critical stages of their fetal development 1 make this only too clear. 2 At the same time, however, the law also permits abortion: the deliberate and intentional killing of fetuses at precisely those stages of their development at which thalidomide damage would be sustained were the drug to be administered. 3 In adopting these two stances, the law appears to find itself in a position of conflict. For the right to sue for damages is reserved solely for those individuals which in one sense or another are persons; 4 and in taking a favourable stance in the thalidomide cases, 5 the law seems to be operating on the principle that those individuals who suffer morphological damage as a result of exposure to the drug in fact enjoyed the status of persons at that particular time. On the other hand, in permitting abortions to occur at that particular stage of fetal development, the law seems to be operating on the principle that these individuals are not yet persons; 6 for otherwise, the act of abortion would be one of murder

The Euthanasia of Radically Defective Neonates: Some Statutory Considerations

Advances in medical technology, discoveries in pharmacology, an developments in bio-engineering have made it possible for the modem physician to save and/or sustain the lives of individuals who but a few decades ago would have died. These developments have proved a mixed blessing. While on the one hand they have allowed the physician to exercise his profession more successfully, on the other they have opened up before him a domain of decision problems that few of his predecessors have had to face. The thrust of these problems may be focussed into a single question: Ought he to employ the techniques, drugs and devices thus at his disposal in all cases, or ought he to proceed selectively

High-tech and low-tech orthopaedic surgery in Sub-Saharan Africa

BACKGROUND: Zambia's governmental health system suffers from shortage of surgical supplies and poor management skills for the sparse resources at hand. The situation has been worsened by the dual epidemics of HIV disease and tuberculosis. On the other hand the private medical sector has benefited greatly from less bureaucracy under the goverment of the Movement for Multi-party Democracy. DISCUSSION: The Zambian-Italian Orthopaedic Hospital in Lusaka is a well organized small unit providing free treatment of physically disabled children. The running costs are met from the fees charged for private consultations, supplemented by donations. State of the art surgical techniques are being used for congenital and acquired musculo-skeletal abnormalities. Last year 513 patients were operated upon free of charge and 320 operations were performed on private patients

Ultrastable Optical Clock with Neutral Atoms in an Engineered Light Shift Trap

An ultrastable optical clock based on neutral atoms trapped in an optical lattice is proposed. Complete control over the light shift is achieved by employing the $5s^2 {}^1S_0 \to 5s5p {}^3P_0$ transition of ${}^{87}{\rm Sr}$ atoms as a "clock transition". Calculations of ac multipole polarizabilities and dipole hyperpolarizabilities for the clock transition indicate that the contribution of the higher-order light shifts can be reduced to less than 1 mHz, allowing for a projected accuracy of better than $10^{-17}$.Comment: 4 pages, 2 figures, accepted for publication in Phys. Rev. Let

Diffusion and jump-length distribution in liquid and amorphous Cu33_{33}Zr67_{67}

Using molecular dynamics simulation, we calculate the distribution of atomic jum ps in Cu$_{33}$Zr$_{67}$ in the liquid and glassy states. In both states the distribution of jump lengths can be described by a temperature independent exponential of the length and an effective activation energy plus a contribution of elastic displacements at short distances. Upon cooling the contribution of shorter jumps dominates. No indication of an enhanced probability to jump over a nearest neighbor distance was found. We find a smooth transition from flow in the liquid to jumps in the g lass. The correlation factor of the diffusion constant decreases with decreasing temperature, causing a drop of diffusion below the Arrhenius value, despite an apparent Arrhenius law for the jump probability