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

The James Webb Space Telescope Mission

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit.Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figure

The Move to Artist-led Online Music Distribution: Explaining structural changes

The market for music products has recently been subject to dramatic forces for change. We propose a model and theoretical perspective for understanding the transformation of the market structure in the recorded music industry value chain due to new forms of digital distribution. We take into account the traditional music industry’s value chain and distribution network, and the product characteristics of digital music as they relate to consumer value creation. We also showcase changes in market structure from the various perspectives of the players in the music industry value chain. We then present propositions that characterize the forces at work in market transformation and how each player’s role in the digital music industry value chain is likely to change. We also explain how intellectual property rights issues are affected by the market structure changes. Finally, we explore a number of industry mini-cases that provide evidence in support of our proposed theoretical perspective. _____________________________________________________________________________

Sulfatase activity in the oyster Crassostrea virginica: its potential interference with sulfotransferase determination

4 pages, 2 figures.-- PMID: 15963577 [PubMed].-- Printed version published Aug 15, 2005.Two sulfatase isoforms, a soluble one with an optimum pH of 5.0, and a microsomal one with an optimum pH of 7.6, were observed in digestive gland, gonads, mantle and gills of the oyster C. virginica. The highest sulfatase activity was recorded in the digestive gland cytosol and is likely to interfere with the in vitro determination of sulfotransferase activity. Indeed, the sulfatase inhibitor Na2SO3 led to an increase of measured sulfotransferase activity (31 ± 9%), suggesting that those sulfatases might be partially responsible for the low sulfotransferase activities found in C. virginica.Peer reviewe

Esterification of vertebrate-type steroids in the Eastern oyster (Crassostrea virginica)

8 pages, 5 figures, 2 tables.-- PMID: 15013691 [PubMed].Characteristics of acyl-coenzyme A (acyl-CoA):steroid acyltransferase from the digestive gland of the oyster Crassostrea virginica were determined by using estradiol (E2) and dehydroepiandrosterone (DHEA) as substrates. The apparent Km and Vmax values for esterification of E2 with the six fatty acid acyl-CoAs tested (C20:4, C18:2, C18:1, C16:1, C18:0, and C16:0) were in the range of 9–17 μM E2 and 35–74 pmol/min/mg protein, respectively. Kinetic parameters for esterification of DHEA (Km: 45–120 μM; Vmax: 30–182 pmol/min/mg protein) showed a lower affinity of the enzyme for this steroid. Formation of endogenous fatty acid esters of steroids by microsomes of digestive gland and gonads incubated in the presence of ATP and CoA was assessed, and at least seven E2 fatty acid esters and five DHEA fatty acid esters were observed. Some peaks eluted at the same retention times as palmitoleoyl-, linoleoyl-, oleoyl/palmitoyl-, and stearoyl-E2; and palmitoleoyl-, oleoyl/palmitoyl-, and stearoyl-DHEA. The same endogenous esters, although in different proportions, were produced by gonadal microsomes. The kinetic parameters for both E2 (Km: 10 μM; Vmax: 38 pmol/min/mg protein) and DHEA (Km: 61 μM; Vmax: 60 pmol/min/mg protein) were similar to those obtained in the digestive gland. Kinetic parameters obtained are similar to those observed in mammals; thus, fatty acid esterification of sex steroids appears to be a well-conserved conjugation pathway during evolution.Partial support from NIEHS Center Grant No. ES05022, and EU Project BEEP (ENVK3-CT-2000-00025).Peer reviewe