Lawson criterion for ignition exceeded in an inertial fusion experiment

For more than half a century, researchers around the world have been engaged in attempts to achieve fusion ignition as a proof of principle of various fusion concepts. Following the Lawson criterion, an ignited plasma is one where the fusion heating power is high enough to overcome all the physical processes that cool the fusion plasma, creating a positive thermodynamic feedback loop with rapidly increasing temperature. In inertially confined fusion, ignition is a state where the fusion plasma can begin "burn propagation" into surrounding cold fuel, enabling the possibility of high energy gain. While "scientific breakeven" (i.e., unity target gain) has not yet been achieved (here target gain is 0.72, 1.37 MJ of fusion for 1.92 MJ of laser energy), this Letter reports the first controlled fusion experiment, using laser indirect drive, on the National Ignition Facility to produce capsule gain (here 5.8) and reach ignition by nine different formulations of the Lawson criterion

Nucleotide sequence of the Tn10 encoded tetracycline resistance gene.

The nucleotide sequence of 1530 base pairs of Tn10 DNA coding for tetracycline resistance has been determined. The gene start consists of overlapping bidirectional promotors and two operator sequences. One terminator of transcription as defined by the typical terminator sequence is about 1300 base pairs downstream from the promotor. It is preceeded by translation termination codons in all three possible reading frames. The transcript contains an open reading frame coding for a 43.3 kDa protein. Two other possible reading frames are discussed. The amino acid sequence of the Tn10 encoded tetracycline resistance gene shows good homology with two proteins encoded in the tetracycline resistance part of the plasmid pBR322. The hydrophobic nature of the 43.3 kDa protein is discussed with regard to it's proposed function

Long bone human anlage longitudinal and circumferential growth in the fetal period and comparison with the growth plate cartilage of the postnatal age

The patterns of longitudinal and peripheral growth were analyzed in human autopod cartilage anlagen (fetal developmental stage 20th-22nd week) through morphometric assessment of chondrocyte parameter size, shape, alignment and orientation between peripheral and central sectors of the anlage transition zone defined by primary ossification center and the epiphyseal basis. The aim was to correlate the chondrocyte dynamics with the longitudinal and peripheral growth. A further comparison was carried out between the corresponding sectors of the postnatal (3-5 months old) growth plate cartilage documenting: (1) the different chondrocyte framework and the new peripheral mechanism; (2) the opposite direction of fetal periosteal ossification versus the Lacroix bone bark. Measurement of multiple parameters (% lac area, % total matrix area, total lac density and mean single lac area), which characterize the cartilage Anlage growth, suggested the following correlations with chondrocyte duplication rate: (a) slow duplication rate approximate to coupled, intralacunar chondrocytes (in central epiphysis); (b) repeated/frequent cell duplications approximate to clusters (in the basal epiphyseal layer); (c) clusters of chondrocytes before becoming hypertrophic were stacked up on the top of each other (both in the Anlage transition zone or in the columns of metaphyseal growth plate); (d) enhanced osteoclastic resorption of the Lacroix bone bark lower end, extended to the more external metaphyseal trabeculae counterbalancing the discrepancy between the epiphyseal and the diaphyseal circumferential growth

Multinucleon transfer in the interaction of 58Ni with 124Sn around the Coulomb barrier

Relative cross-sections for 1, 2, 3, (4, 5) neutron pick-up from a124Sn target were measured at θlab=70° with a58Ni beam energy of 249 MeV; pairing correlations in the two interacting nuclei and kinematical effects strongly affect the cross-sections; the possibility of observing coherent multipair transfer is discussed