53 research outputs found
Considerations for spacecraft design for MSAT
The paper describes the system design considerations and design activities performed at Spar Aerospace in the last 18 months in support of the development of a Canadian Mobile Communication Satellite (MSAT). Recent evolving international agreements and events of importance to MSAT are the emergence of the U.S. Operator and the Mobile WARC 1987. Their impacts on the system requirements and system design are discussed. Solutions to these new requirements are implemented into the 9 Beam baseline design. The system design and the parallel technology development permit the support of a commercial flight program
The next detectors for gravitational wave astronomy
This paper focuses on the next detectors for gravitational wave astronomy
which will be required after the current ground based detectors have completed
their initial observations, and probably achieved the first direct detection of
gravitational waves. The next detectors will need to have greater sensitivity,
while also enabling the world array of detectors to have improved angular
resolution to allow localisation of signal sources. Sect. 1 of this paper
begins by reviewing proposals for the next ground based detectors, and presents
an analysis of the sensitivity of an 8 km armlength detector, which is proposed
as a safe and cost-effective means to attain a 4-fold improvement in
sensitivity. The scientific benefits of creating a pair of such detectors in
China and Australia is emphasised. Sect. 2 of this paper discusses the high
performance suspension systems for test masses that will be an essential
component for future detectors, while sect. 3 discusses solutions to the
problem of Newtonian noise which arise from fluctuations in gravity gradient
forces acting on test masses. Such gravitational perturbations cannot be
shielded, and set limits to low frequency sensitivity unless measured and
suppressed. Sects. 4 and 5 address critical operational technologies that will
be ongoing issues in future detectors. Sect. 4 addresses the design of thermal
compensation systems needed in all high optical power interferometers operating
at room temperature. Parametric instability control is addressed in sect. 5.
Only recently proven to occur in Advanced LIGO, parametric instability
phenomenon brings both risks and opportunities for future detectors. The path
to future enhancements of detectors will come from quantum measurement
technologies. Sect. 6 focuses on the use of optomechanical devices for
obtaining enhanced sensitivity, while sect. 7 reviews a range of quantum
measurement options
Managing software engineers and their knowledge
This chapter begins by reviewing the history of software engineering as a profession, especially the so-called software crisis and responses to it, to help focus on what it is that software engineers do. This leads into a discussion of the areas in software engineering that are problematic as a basis for considering knowledge management issues. Some of the previous work on knowledge management in software engineering is then examined, much of it not actually going under a knowledge management title, but rather “learning” or “expertise”. The chapter goes on to consider the potential for knowledge management in software engineering and the different types of knowledge management solutions and strategies that might be adopted, and it touches on the crucial importance of cultural issues. It concludes with a list of challenges that knowledge management in software engineering needs to address
The Irish Rover: Phil Lynott and the Search for Identity
Phil Lynott, the lead singer of the rock band Thin Lizzy, was a complex character. An illegitimate black child who grew up in a working-class, Catholic district of Dublin, Ireland in the 1950s, Lynott spent his life searching for a sense of belonging, something which he explored through rock and roll. This study uses Lynott’s song lyrics to investigate his quest for identity. In particular, it identifies the many recurring themes and archetypes in his music that offered multifaceted self-portraits of his internal conflict between being black, Irish, illegitimate, a rockstar, a Lothario, a son, a father, and a husband, all at the same time
Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans
Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have
fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in
25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16
regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of
correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP,
while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in
Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium
(LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region.
Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant
enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the
refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa,
an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of
PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent
signals within the same regio
Total cross section of calcium for neutrons between the energies of 20 and 70 Mev.
The total cross section of calcium for neutrons has been measured between the energies of 20 and 70 mev. Increased energy resolution has allowed the cross section to be examined in detail. The cross section was found to have a maximum of 2.5 barns at 48 mev., a minimum of 1.3 barns at 37 mev., and arise again to 2.9 barns at 21 mev. The maximum and minimum have been found to be much more pronounced for calcium than reported previously for other elements. This is tentatively assumed to be due to the increased energy resolution as well as to differences between elements
Health investment, saving, and public policy
This paper develops an overlapping-generations model in which agents invest in health to prolong life in both working and retirement periods. It explores how unfunded social security with or without health subsidies affects life expectancy, economic growth, and welfare. In particular, by extending life at a possible cost of capital accumulation, health subsidies and a pay-as-you-go pension can improve welfare, especially in the short run
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