295 research outputs found
Paper Session II-A - Lockheed Martin\u27s Next Generation Launch Systems
The space launch industry is experiencing a tremendous transition from a government dominated customer base to a commercial customer base. According to the Teal Group World Space Briefing, nearly 75 percent of satellites launched from 1997 to 2006 will be civil and commercial satellites (figure 1). Of these, the vast majority are commercial ventures in mobile communications, broadband multi-media services, or direct broadcast television satellites. Nearly three quarters of all proposed payloads are destined for Low Earth Orbit (LEO). Virtually all LEO satellites will belong to multi-satellite systems involving mobile communications or multimedia services. Lockheed Martin is a world leader in the expendable launch vehicle industry. Our heritage which began with the Titan and Atlas launch systems in the late 1950’s, has spanned four decades and over 1,000 launches. In the late 1980’s, the former General Dynamics Space Systems (GD), recognized the need to develop a launch vehicle that could compete in the international commercial market. In 1987, GDinitiated the first commercial launch vehicle, the Atlas II. TheAtlas vehicle has successfully evolved from II to IIA to IIAS and into today’s newest most powerful system yet - the Atlas IIAR which will be operational in late 1998. The driving force behind each system upgrade has been to improve performance while reducing cost and increasing reliability.
Lockheed Martin combined the commercial industry expertise of the Atlas program with the heritage hardware of both the Atlas and Titan programs to develop their next generation launch vehicle the Common Core BoosterTM family. The Common Core BoosterTM family of launch vehicles will accommodate a wide range of customers, by providing a highly reliable, responsive system with streamlined launch operations. The Common Core BoosterTM vehicle allows Lockheed Martin tol effectively compete in international commercial markets, while satisfying the United States government requirements for low cost, reliable access to space. The purpose of this paper is to describe Lockheed Martin’s approach to incorporating the benefits and lessons learned from the Atlas and Titan launch systems into a launch vehicle family that will serve the payload community well into the 21st Century
Resolving Animal Distress and Pain: Principles and Examples of Good Practice in Various Fields of Research
Pain and distress are central topics in legislation, regulations, and standards regarding the use of animals in research. However, in practice, pain has received greatly increased attention in recent years, while attention to distress has lagged far behind, especially for distress that is not induced by pain. A contributing factor is that there is less information readily available on distress, including practical information on its recognition, assessment and alleviation.
This chapter attempts to help fill that void by reversing the usual pattern and giving greater attention to distress than to pain. In addition, we also bypass the pain versus distress dichotomy by adopting a holistic treatment of adverse effects, i.e., not parsing distress and pain, by providing guidance on how to assess deviations from normality through tools such as score sheets. Our aim is to provide practical information to IACUCs, scientists, technicians and animal care personnel.
We organize the chapter according to specific research areas and case studies. However, the principles and approaches are readily generalized to other research areas.
CONTENTS Effect of surgical technical skill on pain and distress in animals - Alicia Karas, DVM Carbon dioxide euthanasia: example of aversion techniques - Matthew C. Leach, PhD The Refinement of Infectious Disease Research - Karl A. Andrutis DVM, MS, DACLAM Polyclonal antibody production - Kathleen Conlee, BS, MPA Animal models of human psychopathology: anxiety - John P. Gluck PhD Refinement In Toxicology Testing: A Workshop to Promote Current Advances and Disseminate Best Practices - Andrew N. Rowan, Martin L. Stephens, and Kathleen M. Conle
Designer diatom episomes delivered by bacterial conjugation.
Eukaryotic microalgae hold great promise for the bioproduction of fuels and higher value chemicals. However, compared with model genetic organisms such as Escherichia coli and Saccharomyces cerevisiae, characterization of the complex biology and biochemistry of algae and strain improvement has been hampered by the inefficient genetic tools. To date, many algal species are transformable only via particle bombardment, and the introduced DNA is integrated randomly into the nuclear genome. Here we describe the first nuclear episomal vector for diatoms and a plasmid delivery method via conjugation from Escherichia coli to the diatoms Phaeodactylum tricornutum and Thalassiosira pseudonana. We identify a yeast-derived sequence that enables stable episome replication in these diatoms even in the absence of antibiotic selection and show that episomes are maintained as closed circles at copy number equivalent to native chromosomes. This highly efficient genetic system facilitates high-throughput functional characterization of algal genes and accelerates molecular phytoplankton research
Role of electric charge in shaping equilibrium configurations of fluid tori encircling black holes
Astrophysical fluids may acquire non-zero electrical charge because of strong
irradiation or charge separation in a magnetic field. In this case,
electromagnetic and gravitational forces may act together and produce new
equilibrium configurations, which are different from the uncharged ones.
Following our previous studies of charged test particles and uncharged perfect
fluid tori encircling compact objects, we introduce here a simple test model of
a charged perfect fluid torus in strong gravitational and electromagnetic
fields. In contrast to ideal magnetohydrodynamic models, we consider here the
opposite limit of negligible conductivity, where the charges are tied
completely to the moving matter. This is an extreme limiting case which can
provide a useful reference against which to compare subsequent more complicated
astrophysically-motivated calculations. To clearly demonstrate the features of
our model, we construct three-dimensional axisymmetric charged toroidal
configurations around Reissner-Nordstr\"om black holes and compare them with
equivalent configurations of electrically neutral tori.Comment: 14 pages, 7 figure
Direct Transfer of a Mycoplasma mycoides Genome to Yeast Is Enhanced by Removal of the Mycoides Glycerol Uptake Factor Gene glpF
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