10,139 research outputs found
Software Implemented Fault-Tolerant (SIFT) user's guide
Program development for a Software Implemented Fault Tolerant (SIFT) computer system is accomplished in the NASA LaRC AIRLAB facility using a DEC VAX-11 to interface with eight Bendix BDX 930 flight control processors. The interface software which provides this SIFT program development capability was developed by AIRLAB personnel. This technical memorandum describes the application and design of this software in detail, and is intended to assist both the user in performance of SIFT research and the systems programmer responsible for maintaining and/or upgrading the SIFT programming environment
Panoramic Views of the Cygnus Loop
We present a complete atlas of the Cygnus Loop supernova remnant in the light
of [O III] (5007), H alpha, and [S II] (6717, 6731). Despite its shell-like
appearance, the Cygnus Loop is not a current example of a Sedov-Taylor blast
wave. Rather, the optical emission traces interactions of the supernova blast
wave with clumps of gas. The surrounding interstellar medium forms the walls of
a cavity through which the blast wave now propagates, including a nearly
complete shell in which non-radiative filaments are detected. The Cygnus Loop
blast wave is not breaking out of a dense cloud, but is instead running into
confining walls. The interstellar medium dominates not only the appearance of
the Cygnus Loop but also the continued evolution of the blast wave. If this is
a typical example of a supernova remnant, then global models of the
interstellar medium must account for such significant blast wave deceleration.Comment: 28 pages AAS Latex, 28 black+white figures, 6 color figures. To be
published in The Astrophysical Journal Supplement Serie
d=2, N=2 Superconformal Symmetries and Models
We discuss the following aspects of two-dimensional N=2 supersymmetric
theories defined on compact super Riemann surfaces: parametrization of (2,0)
and (2,2) superconformal structures in terms of Beltrami coefficients and
formulation of superconformal models on such surfaces (invariant actions,
anomalies and compensating actions, Ward identities).Comment: 43 pages, late
Zoledronic acid in metastatic chondrosarcoma and advanced sacrum chordoma: two case reports
<p>Abstract</p> <p>Introduction</p> <p>Chondrosarcomas and chordomas are usually chemoresistant bone tumors and may have a poor prognosis when advanced. They are usually associated with worsening pain difficult to control.</p> <p>Patients and Methods</p> <p>Zoledronic acid was used in a 63-year-old man with metastatic chondrosarcoma and in a 66-year-old woman with a diagnosis of sacrum chordoma both reporting severe pain related to tumor.</p> <p>Results</p> <p>In the first case, zoledronic acid was able to maintain pain control despite disease progression following chemotherapy, in the other case, zoledronic acid only produced significant clinical benefit.</p> <p>Conclusion</p> <p>Control of pain associated with bone tumors such as chondrosarcoma and chondroma may significantly improve from use of zoledronic acid, independently from tumor response to other treatments. Evaluation on larger series are needed to confirm the clinical effect of this bisphosphonate on such tumors.</p
Electroproduction of the d* dibaryon
The unpolarized cross section for the electroproduction of the isoscalar
di-delta dibaryon is calculated for deuteron target using a
simple picture of elastic electron-baryon scattering from the and the components of the deuteron. The calculated
differential cross section at the electron lab energy of 1 GeV has the value of
about 0.24 (0.05) nb/sr at the lab angle of 10 (30) for the
Bonn B potential when the dibaryon mass is taken to be 2.1 GeV. The cross
section decreases rapidly with increasing dibaryon mass. A large calculated
width of 40 MeV for combined with a small
experimental upper bound of 0.08 MeV for the decay width appears to have
excluded any low-mass model containing a significant admixture of the
configuration.Comment: 11 journal-style pages, 8 figure
Green-Schwarz Formulation of Self-Dual Superstring
The self-dual superstring has been described previously in a
Neveu-Schwarz-Ramond formulation with local N=2 or 4 world-sheet supersymmetry.
We present a Green-Schwarz-type formulation, with manifest spacetime
supersymmetry.Comment: 11 pg., (uuencoded dvi file) ITP-SB-92-5
Quantising Gravity Using Physical States of a Superstring
A symmetric zero mass tensor of rank two is constructed using the superstring
modes of excitation which satisfies the physical state constraints of a
superstring. These states have one to one correspondence with quantised
operators and are shown to be the absorption and emission quanta of the
Minkowski space Lorentz tensors using the Gupta-Bleuler method of quantisation.
The principle of equivalence makes the tensor identical to the metric tensor at
any arbitrary space-time point. The propagator for the quantised field is
deduced. The gravitational interaction is switched on by going over from
ordinary derivatives to coderivatives.The Riemann-Christoffel affine
connections are calculated and the weak field Ricci tensor is
shown to vanish. The interaction part is found out and the
exact of theory of gravity is expressed in terms of the quantised
metric. The quantum mechanical self energy of the gravitational field, in
vacuum, is shown to vanish. It is suggested that quantum gravity may be
renormalisable by the use of the physical ground states of the superstring
theory.Comment: 14 page
Genome-wide linkage analysis of 972 bipolar pedigrees using single-nucleotide polymorphisms.
Because of the high costs associated with ascertainment of families, most linkage studies of Bipolar I disorder (BPI) have used relatively small samples. Moreover, the genetic information content reported in most studies has been less than 0.6. Although microsatellite markers spaced every 10âcM typically extract most of the genetic information content for larger multiplex families, they can be less informative for smaller pedigrees especially for affected sib pair kindreds. For these reasons we collaborated to pool family resources and carried out higher density genotyping. Approximately 1100 pedigrees of European ancestry were initially selected for study and were genotyped by the Center for Inherited Disease Research using the Illumina Linkage Panel 12 set of 6090 single-nucleotide polymorphisms. Of the ~1100 families, 972 were informative for further analyses, and mean information content was 0.86 after pruning for linkage disequilibrium. The 972 kindreds include 2284 cases of BPI disorder, 498 individuals with bipolar II disorder (BPII) and 702 subjects with recurrent major depression. Three affection status models (ASMs) were considered: ASM1 (BPI and schizoaffective disorder, BP cases (SABP) only), ASM2 (ASM1 cases plus BPII) and ASM3 (ASM2 cases plus recurrent major depression). Both parametric and non-parametric linkage methods were carried out. The strongest findings occurred at 6q21 (non-parametric pairs LOD 3.4 for rs1046943 at 119âcM) and 9q21 (non-parametric pairs logarithm of odds (LOD) 3.4 for rs722642 at 78âcM) using only BPI and schizoaffective (SA), BP cases. Both results met genome-wide significant criteria, although neither was significant after correction for multiple analyses. We also inspected parametric scores for the larger multiplex families to identify possible rare susceptibility loci. In this analysis, we observed 59 parametric LODs of 2 or greater, many of which are likely to be close to maximum possible scores. Although some linkage findings may be false positives, the results could help prioritize the search for rare variants using whole exome or genome sequencing
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