M.-H. Kim

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We present the first measurement of the rate of Type Ia supernovae at high redshift. The result is derived using a large subset of data from the Supernova Cosmology Project. Three supernovae were discovered in a surveyed area of 1.7 square degrees. The survey spanned a ∼ 3 week baseline and used images with 3σ limiting magnitude of R ∼ 23. We present our(More)
We have developed a technique to systematically discover and study high-redshift supernovae that can be used to measure the cosmological parameters. We report here results based on the initial seven of >28 supernovae discovered to date in the high-redshift supernova search of the Supernova Cosmology Project. We find a dispersion in peak magnitudes of σ M B(More)
The ultimate fate of the Universe, infinite expansion or a big crunch, can be determined by using the redshifts and distances of very distant supernovae to monitor changes in the expansion rate. We can now find 1 large numbers of these distant supernovae, and measure their redshifts and apparent brightnesses; moreover, recent studies of nearby type Ia(More)
In this study we have identified a new structural motif for a ligand with G-quadruplex interaction that results in biological effects associated with G-quadruplex-interactive compounds. Fluoroquinolones have been reported to possess weak telomerase inhibitory activity in addition to their better known bacterial gyrase poisoning. Starting with a(More)
Introduction Methods by which radiation shielding is optimized need to be developed and materials of improved shielding characteristics identified and validated. The GCR are very penetrating and the energy absorbed by the astronaut behind the shield is nearly independent of shield composition and even the shield thickness. However, the mix of particles in(More)
Introduction: Protection against the hazards from exposure to ionizing radiation remains an unresolved issue in the Human Exploration and Development of Space (HEDS) enterprise [1]. The major uncertainty is the lack of data on biological response to galactic cosmic ray (GCR) exposures but even a full understanding of the physical interaction of GCR with(More)
Many different stimuli such as bioactive agents and environmental stresses are known to cause the activation of sphingomyelinase (SMase), which hydrolyzes sphingomyelin to generate ceramide as a second messenger playing a key role in differentiation and apoptosis in various cell types. Here we identified multiple forms of the membrane-associated neutral(More)
The development of Mars for human activity will require the utilization of Martian materials in building habitats and working structures. One approach is to use polymer binders with regolith to form structural elements. Not only can useful composite materials be produced in this way but the radiation protection properties are also increased. This is(More)
The solar particle event (SPE) of September 29, 1989, produced an iron-rich spectrum with energies approaching 1 GeV/amu with an energy power index of 2.5. These high charge and energy (HZE) ions of the iron-rich SPEs challenge conventional methods of SPE shield design and assessment of astronaut risks. Shield and risk assessments are evaluated using the(More)