15 research outputs found
The redwood project: An overview
Redwood is a new generation tape subsystem now under development at StorageTek using helical scan technology. This library based storage subsystem is designed for the high performance, deep archival market. The topics are presented in viewgraph form and include the following: subsystem overview, media standards, Redwood developed tape, D3 helical recording format, Redwood cartridge, host software for Redwood libraries, and market opportunities
The standards process: Technical committee X3B5 digital magnetic tape
The definition of X3B5, where it fits in the national and international standards development process, and how it interfaces and influences the world community of standards developers are provided. Details concerning the focus of the committee, how it operates, and what the group sees as the future trends in the area of interchange standards utilizing the multifaceted, ubiquitous magnetic tape are presented
Search for dark matter produced in association with bottom or top quarks in √s = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fb−1 of proton–proton collision data recorded by the ATLAS experiment at √s = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Observations of the chemistry and concentrations of reactive Hg at locations with different ambient air chemistry
The Hg research community needs methods to more accurately measure atmospheric Hg concentrations and chemistry. The Reactive Mercury Active System (RMAS) uses cation exchange, nylon, and PTFE membranes to determine reactive mercury (RM), gaseous oxidized mercury, and particulate-bound mercury (PBM) concentrations and chemistry, respectively. New data for Atlanta, Georgia (NRGT) demonstrated that particulate-bound Hg was dominant and the chemistry was primarily N and S HgII compounds. At Great Salt Lake, Utah (GSL), RM was predominately PBM, with NS > organics > halogen > O HgII compounds. At Guadalupe Mountains National Park, Texas (GUMO), halogenated compound concentrations were lowest when air interacting with the site was primarily derived from the Midwest, and highest when the air was sourced from Mexico. At Amsterdam Island, Southern Indian Ocean, compounds were primarily halogenated with some N, S, and organic HgII compounds potentially associated with biological activity. The GEOS-Chem model was applied to see if it predicted measurements at five field sites. Model values were higher than observations at GSL, slightly lower at NRGT, and observations were an order of magnitude higher than modeled values for GUMO and Reno, Nevada. In general, data collected from 13 locations indicated that N, S, and organic RM compounds were associated with city and forest locations, halogenated compounds were sourced from the marine boundary layer, and O compounds were associated with long-range transport. Data being developed currently, and in the past, suggest there are multiple forms of RM that modelers must consider, and PBM is an important component of RM
Targeted Disruption of ROCK1 Causes Insulin Resistance in Vivo*S⃞
Insulin signaling is essential for normal glucose homeostasis. Rho-kinase
(ROCK) isoforms have been shown to participate in insulin signaling and
glucose metabolism in cultured cell lines. To investigate the physiological
role of ROCK1 in the regulation of whole body glucose homeostasis and insulin
sensitivity in vivo, we studied mice with global disruption of ROCK1.
Here we show that, at 16–18 weeks of age, ROCK1-deficient mice exhibited
insulin resistance, as revealed by the failure of blood glucose levels to
decrease after insulin injection. However, glucose tolerance was normal in the
absence of ROCK1. These effects were independent of changes in adiposity.
Interestingly, ROCK1 gene ablation caused a significant increase in
glucose-induced insulin secretion, leading to hyperinsulinemia. To determine
the mechanism(s) by which deletion of ROCK1 causes insulin resistance, we
measured the ability of insulin to activate phosphatidylinositol 3-kinase and
multiple distal pathways in skeletal muscle. Insulin-stimulated
phosphatidylinositol 3-kinase activity associated with IRS-1 or
phospho-tyrosine was also reduced ∼40% without any alteration in tyrosine
phosphorylation of insulin receptor in skeletal muscle. Concurrently, serine
phosphorylation of IRS-1 at serine 632/635, which is phosphorylated by ROCK
in vitro, was also impaired in these mice. Insulin-induced
phosphorylation of Akt, AS160, S6K, and S6 was also decreased in skeletal
muscle. These data suggest that ROCK1 deficiency causes systemic insulin
resistance by impairing insulin signaling in skeletal muscle. Thus, our
results identify ROCK1 as a novel regulator of glucose homeostasis and insulin
sensitivity in vivo, which could lead to new treatment approaches for
obesity and type 2 diabetes