3,949 research outputs found
Three computer programs for n-body trajector- ies and interplanetary trajectories
Input and operating instructions, and sample problems for IBM 7094 computer programs - interplanetary trajectory program, n-body trajectory program, and sensitivity coefficient
Distillation of Strangelets for low initial mu/T
We calculate the evolution of quark-gluon-plasma droplets during the
hadronization in a thermodynamical model. It is speculated that cooling as well
as strangeness enrichment allow for the formation of strangelets even at very
high initial entropy per baryon and low initial
baryon numbers of . It is shown that the
droplet with vanishing initial chemical potential of strange quarks and a very
moderate chemical potential of up/down quarks immediately charges up with
strangeness. Baryon densities of and strange chemical
potentials of ~MeV are reached if strangelets are stable. The
importance of net--baryon and net--strangeness fluctuations for the possible
strangelet formation at RHIC and LHC is emphasized
Development and tests of Double-sided Silicon Strip Detectors and Read-Out Electronics for the Internal Tracking System of ALICE at LHC
Presentation given at Quark Matter '99, Torino, Italy, 10-15 May 1999The internal-tracking-system (ITS) of the ALICE detector at LHC consists of six concentrical barrels of silicon detectors. The outmost two layers are made of double-sided strip detectors (SSD). In the framework of R&D, the characteristics and performances of these devices, manufactured by two different companies, associated with their designed read-out electronics, have been studied off- and in-beam at the SPS (CERN). The results are presented and discussed
Search for Strangeness at new Ultra-relativistic Heavy-ion Colliders
The Relativistic Heavy-Ion Collider (RHIC) is operating since a few months. The Large Hadron Collider (LHC) will be operational around 2005. They will be served by several experiments of considerable scale. Among them, the STAR and the ALICE experiments are dedicated to the study of fundamental aspects linked to an expected phase transition between the hadronic and a deconfined-quark state of nuclear matter. Numerous experimental approaches are offered by the versatility of these experiments, one of the most effective is the study of the strangeness production. An expected intringing form of strangeness is the Ho, the result of a uuddss quark state or of a 2Lambdao aggregation. The presentation will deal with the strangeness study and with possible experimental attempts to identify such a Ho nuclear state, thus extending the promising general study of strangeness
A study of airplane ranges and useful loads
This report is an analysis of the maximum flight radii of typical large airplanes and a discussion of the way in which the possible length of flight is affected by the change of weight by consumption of fuel during the flight
Developmental Angiogenesis: Quail Embryonic Vasculature
We have examined the segregation and early morphogenesis of the embryonic vasculature by using a monoclonal antibody for immunofluorescence and by scanning electron microscopy. This antibody labels the presumptive endothelial eel ls (PECs) as they segregate from mesoderm. Similar embryos prepared for SEM revealed finer details of how these segregated cells interact to form the rudiments of the major blood vessels. Here we concentrate on the development of the dorsal aortae and the posterior cardinal veins. The dorsal aortae form from single PECs which segregate from the lateral mesoderm and aggregate into a loose cord ventral to the somites. These cells become more closely associated and a lumen forms. The posterior cardinal veins form from a loose plexus of cells segregated from the lateral mesoderm on its dorsal surface. These cells become intimately associated with the Wolffian ducts
Learning the language of school history: the role of linguistics in mapping the writing demands of the secondary school curriculum
This paper reports on a research study which used the tools of functional linguistics to illuminate the writing requirements of the history curriculum in the context of Australian secondary schools. It shows how the resulting linguistic description was integrated into a sequence of teaching and learning activities through collaboration between linguist specialists and content/pedagogic specialists. These activities were designed to facilitate studentsâ writing skills whilst simultaneously developing their historical knowledge. An independent evaluation of the approach pointed to positive changes in teachersâ attitudes and behaviours regarding the role of language in learning history. Equally, studentsâ writing improved, particularly in terms of its organisation and structure
ATF3 upregulation in glia during Wallerian degeneration: differential expression in peripheral nerves and CNS white matter
Background: Many changes in gene expression occur in distal stumps of injured nerves but the transcriptional control of these events is poorly understood. We have examined the expression of the transcription factors ATF3 and c-Jun by non-neuronal cells during Wallerian degeneration following injury to sciatic nerves, dorsal roots and optic nerves of rats and mice, using immunohistochemistry and in situ hybridization.Results: Following sciatic nerve injury-transection or transection and reanastomosis-ATF3 was strongly upregulated by endoneurial, but not perineurial cells, of the distal stumps of the nerves by 1 day post operation (dpo) and remained strongly expressed in the endoneurium at 30 dpo when axonal regeneration was prevented. Most ATF3+ cells were immunoreactive for the Schwann cell marker, S100. When the nerve was transected and reanastomosed, allowing regeneration of axons, most ATF3 expression had been downregulated by 30 dpo. ATF3 expression was weaker in the proximal stumps of the injured nerves than in the distal stumps and present in fewer cells at all times after injury. ATF3 was upregulated by endoneurial cells in the distal stumps of injured neonatal rat sciatic nerves, but more weakly than in adult animals. ATF3 expression in transected sciatic nerves of mice was similar to that in rats. Following dorsal root injury in adult rats, ATF3 was upregulated in the part of the root between the lesion and the spinal cord (containing Schwann cells), beginning at 1 dpo, but not in the dorsal root entry zone or in the degenerating dorsal column of the spinal cord. Following optic nerve crush in adult rats, ATF3 was found in some cells at the injury site and small numbers of cells within the optic nerve displayed weak immunoreactivity. The pattern of expression of c-Jun in all types of nerve injury was similar to that of ATF3.Conclusion: These findings raise the possibility that ATF3/c-Jun heterodimers may play a role in regulating changes in gene expression necessary for preparing the distal segments of injured peripheral nerves for axonal regeneration. The absence of the ATF3 and c-Jun from CNS glia during Wallerian degeneration may limit their ability to support regeneration
Using exchange structure analysis to explore argument in text-based computer conferences
Computer conferencing provides a new site for students to develop and rehearse argumentation skills, but much remains to be learnt about how to encourage and support students in this environment. Asynchronous text-based discussion differs in significant ways from face-to-face discussion, creating a need for specially designed schemes for analysis. This paper discusses some of the problems of analysing asynchronous argumentation, and puts forward an analytical framework based on exchange structure analysis, which brings a linguistic perspective to bear on the interaction. Key features of the framework are attention to both interactive and ideational aspects of the discussion,
and the ability to track the dynamic construction of argument content. The paper outlines the framework itself, and discusses some of the findings afforded by this type of analysis, and its limitations
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