New Keck Observations of Lithium in Very Metal-poor Stars

Lithium abundances have been determined in more than 100 metal-poor halo stars both in the field and in clusters. From these data we find trends of Li with both temperature and metallicity and a real dispersion in Li abundances in the Spite Li plateau. We attribute this dispersion primarily to Li depletion (presumably due to extra mixing induced by stellar rotation) and to Galactic chemical evolution. We derive a primordial Li of 2.44 $\pm$0.18 for A(Li)$_p$ = log N(Li/H) + 12.00. This agrees with the Li abundances predicted by the $WMAP$ results. For stars cooler than the Li plateau we have evidence that Li depletion sets in at hotter temperatures for the higher metallicity stars than for the low-metal stars. This is the opposite sense of predictions from stellar models. The smooth transition of the Li content from the Li plateau stars to the cool stars adds weight to the inference of Li depletion in the plateau stars.Comment: Invited talk for IAU Symposium 228 "From Lithium to Uranium..." held in Paris in May, 2005. 6 pages, 6 figure

Lithium and Lithium Depletion in Halo Stars on Extreme Orbits

We have determined Li abundances in 55 metal-poor (3.6 < [Fe/H] < -0.7) stars with extreme orbital kinematics. We find the Li abundance in the Li-plateau stars and examine its decrease in low-temperature, low-mass stars. The Li observations are primarily from the Keck I telescope with HIRES (spectral resolution of ~48,000 and median signal-to-noise per pixel of 140). Abundances or upper limits were determined for Li for all the stars with typical errors of 0.06 dex. Our 14 stars on the Li plateau give A(Li) = log N(Li)/N(H) + 12.00 of 2.215 +-0.110, consistent with earlier results. We find a dependence of the Li abundance on metallicity as measured by [Fe/H] and the Fe-peak elements [Cr/H] and [Ni/H], with a slope of ~0.18. We also find dependences of A(Li) with the alpha elements, Mg, Ca, and Ti. For the n-capture element, Ba, the relation between A(Li) and [Ba/H] has a shallower slope of 0.13; over a range of 2.6 dex in [Ba/H], the Li abundance spans only a factor of two. We examined the possible trends of A(Li) with the characteristics of the orbits of our halo stars, but find no relationship with kinematic or dynamic properties. The stars cooler than the Li plateau are separated into three metallicity subsets. The decrease in A(Li) sets in at hotter temperatures at high metallicities than at low metallicities; this is in the opposite sense of the predictions for Li depletion from standard and non-standard models.Comment: 29 pages including 3 tables and 12 figures Accepted by The Astrophysical Journal, for the 1 November 2005 issue, v. 63

The Sensor Management for Applied Research Technologies (SMART) Project

NASA seeks on-demand data processing and analysis of Earth science observations to facilitate timely decision-making that can lead to the realization of the practical benefits of satellite instruments, airborne and surface remote sensing systems. However, a significant challenge exists in accessing and integrating data from multiple sensors or platforms to address Earth science problems because of the large data volumes, varying sensor scan characteristics, unique orbital coverage, and the steep "learning curve" associated with each sensor, data type, and associated products. The development of sensor web capabilities to autonomously process these data streams (whether real-time or archived) provides an opportunity to overcome these obstacles and facilitate the integration and synthesis of Earth science data and weather model output

In situ measurements of atmospheric O2 and CO2 reveal an unexpected O2 signal over the tropical Atlantic Ocean

We present the first meridional transects of atmospheric O2 and CO2 over the Atlantic Ocean. We combine these measurements into the tracer atmospheric potential oxygen (APO), which is a measure of the oceanic contribution to atmospheric O2 variations. Our new in situ measurement system, deployed on board a commercial container ship during 2015, performs as well as or better than existing similar measurement systems. The data show small short-term variability (hours to days), a step-change corresponding to the position of the Intertropical Convergence Zone (ITCZ), and seasonal cycles that vary with latitude. In contrast to data from the Pacific Ocean and to previous modeling studies, our Atlantic Ocean APO data show no significant bulge in the tropics. This difference cannot be accounted for by interannual variability in the position of the ITCZ or the Atlantic Meridional Mode Index and appears to be a persistent feature of the Atlantic Ocean system. Modeled APO using the TM3 atmospheric transport model does exhibit a significant bulge over the Atlantic and overestimates the interhemispheric gradient in APO over the Atlantic Ocean. These results indicate that either there are inaccuracies in the oceanic flux data products in the equatorial Atlantic Ocean region, or that there are atmospheric transport inaccuracies in the model, or a combination of both. Our shipboard O2 and CO2 measurements are ongoing and will reveal the long-term nature of equatorial APO outgassing over the Atlantic as more data become available

Accelerating Innovation in the Creation of Biovalue : The Cell and Gene Therapy Catapult

The field of regenerative medicine (RM) has considerable therapeutic promise that is proving difficult to realize. As a result, governments have supported the establishment of intermediary agencies to “accelerate” innovation. This paper examines in detail one such agency, the UK's Cell and Gene Therapy Catapult (CGTC). We describe CGTC’s role as an accelerator agency and its value-narrative, which combines both “health and wealth.” Drawing on the notion of socio-technical imaginaries, we unpack the tensions within this narrative and its instantiation as the CGTC cell therapy infrastructure is built and engages with other agencies, some of which have different priorities and roles to play within the RM field