1,252 research outputs found
Indirect Detection of Neutralino Dark Matter up to TeV Scale
In this paper, we will describe the results of SUSY parameter space searches
including minimal supergravity, non-universal supergravity and minimal
supersymmetry and the implications on the indirect detection of neutralino dark
matter. We give special attention to the effects of detector thresholds, solar
absorption of neutrinos and hadronization of neutralino annihilation products.
These effects are known to be important in calculating accurate event rates.Comment: 10 pages, 9 figures, Proceedings of 30 Years of Supersymmetry,
Minneapolis, MN, October 200
Parameter extraction by Planck for a CDM model with broken scale invariance and cosmological constant
We consider a class of spatially flat cold dark matter (CDM) models, with a
cosmological constant and a broken-scale-invariant (BSI) steplike primordial
spectrum of adiabatic perturbations, previously found to be in very good
agreement with observations. Performing a Fisher matrix analysis, we show that
in case of a large gravitational waves (GW) contribution some free parameters
(defining the step) of our BSI model can be extracted with remarkable accuracy
by the Planck satellite, thanks to the polarisation anisotropy measurements.
Further, cosmological parameters can still be found with very good precision,
despite a larger number of free parameters than in the simplest inflationary
models.Comment: Final version to appear in MNRAS. Minor changes. 5 pages, 1 LaTeX
figure, uses mn.st
Non universal gaugino phases and the LSP relic density
The cosmological relic density of the lightest supersymmetric particle (LSP)
of type I string derived model is calculated. This model can accommodate large
values of CP violating phases, and the electron and neutron electric dipole
moments satisfy the experimental constraint. We show that the constraint from
the electric dipole moment on the ratio between the gaugino masses implies that
the mass of the LSP, which is bino like, is close to the lightest chargino. The
co-annihilation between them is very important to reduce the LSP relic density
to an interesting region. We show that the SUSY phases, although they are
large, have no significant effect on the relic density and on the the upper
bound imposed on the LSP mass. However, they are very significant for the
detection rates. We emphasize that the phase of the trilinear coupling increase
the direct and indirect detection rates.Comment: 10 pages, Latex2e, version to be appeared in Phys. Lett.
Examining the pH switch of copper-zinc superoxide dismutase mutant A4V
Amyotrophic lateral sclerosis(ALS) is a neurodegenerative disease that causes progressive loss to motor neurons. Buildup of superoxide anions (O2-) and aggregation of superoxide dismutase (SOD) is thought to be probable causes of damage to the neurons. This damage results in the progressive loss of function in the neurons resulting in flaccid paralysis. Superoxide anions were originally thought to cause irreparable damage to the motor neurons; however, recent studies have shown that the aggregation of SOD causes damage to the cell. Furthermore, the ability for the SOD1 to get metalated to dissuade aggregation has become an important topic of study in ALS research. In this study, human SOD1 A4V mutant was successfully expressed and purified and set for crystallization at various pH to understand the effect of minor pH changes on the stability of the protein structure. Future X-ray crystallography analysis could result in further understanding of how SOD1 aggregates which might help produce viable treatments for the familial form of ALS
Cosmological-parameter determination with microwave background maps
The angular power spectrum of the cosmic microwave background (CMB) contains information on virtually all cosmological parameters of interest, including the geometry of the Universe (Ω), the baryon density, the Hubble constant (h), the cosmological constant (Λ), the number of light neutrinos, the ionization history, and the amplitudes and spectral indices of the primordial scalar and tensor perturbation spectra. We review the imprint of each parameter on the CMB. Assuming only that the primordial perturbations were adiabatic, we use a covariance-matrix approach to estimate the precision with which these parameters can be determined by a CMB temperature map as a function of the fraction of sky mapped, the level of pixel noise, and the angular resolution. For example, with no prior information about any of the cosmological parameters, a full-sky CMB map with 0.5° angular resolution and a noise level of 15 μK per pixel can determine Ω, h, and Λ with standard errors of ±0.1 or better, and provide determinations of other parameters which are inaccessible with traditional observations. Smaller beam sizes or prior information on some of the other parameters from other observations improves the sensitivity. The dependence on the underlying cosmological model is discussed
Determining the Actual Local Density of Dark Matter Particles
Even if dark matter particles are unambiguously discovered in experiments,
there is no clear reason to expect that the dark matter problem has been
solved. It is very easy to provide examples of dark matter scenarios (e.g. in
supersymmetric models) where nearly identical detector signals correspond to
extremely different relic densities. Therefore, the density of the particles
discovered must be determined before their cosmological relevance is
established. In this talk, I will present a general method to estimate the
local density of dark matter particles using both dark matter and hadron
collider experimental data when it becomes available. These results were
obtained in collaboration with Gordon Kane at the University of Michigan.Comment: 9 pages, 4 figures. Talk given at the 42nd International School of
Subnuclear Physics at Erice, Sicily, 30 August 200
A Study on the Impact of Demographic Change on Housing Price in South Korea
In recent years, the demographic structure of South Korea as been changing. Although the total population is still growing, the population growth rate is shrinking due to the rapid decline in the birth rate and the aging population. On the other hand, the growth rate of the total number of households is decreasing, but the rate of one-person or two-person households is steadily increasing. Data by region from 2003 to 2016 are used to analyze how these changes in the size and composition of population and households affect housing prices. Since the patterns of changes in the housing price and demographic structure by each metropolitan city or the province are different, consequently the regional analyses are implemented as well as the nationwide analysis.
According to the results of the analyses, population variables such as the population growth rate and the elderly dependency ratio have no statistically significant effect on the housing price, while household variables such as the household growth rate and the ratio of small households (1 or 2 people) to all households have a significant effect. In the nationwide analysis, both household factors are statistically significant, but in the regional analysis, only single or two-person household ratio shows meaningful results in the Seoul metropolitan region and the non-metropolitan provinces. Besides the population and household variables, only the growth rate of new housing licenses, which is a housing supply variable, has a significant impact on housing prices regardless of regions.
Therefore, in establishing a housing policy in the future, the government should pay more attention to the household variables than the population variables. Regionally, the small household ratio should be considered more in the Seoul metropolitan region and the non-metropolitan provinces. In addition, it should also examine thoroughly the economic variables such as housing supply
Examining the pH switch of copper-zinc superoxide dismutase mutant A4V
Amyotrophic lateral sclerosis(ALS) is a neurodegenerative disease that causes progressive loss to motor neurons. Buildup of superoxide anions (O2-) and aggregation of superoxide dismutase (SOD) is thought to be probable causes of damage to the neurons. This damage results in the progressive loss of function in the neurons resulting in flaccid paralysis. Superoxide anions were originally thought to cause irreparable damage to the motor neurons; however, recent studies have shown that the aggregation of SOD causes damage to the cell. Furthermore, the ability for the SOD1 to get metalated to dissuade aggregation has become an important topic of study in ALS research. In this study, human SOD1 A4V mutant was successfully expressed and purified and set for crystallization at various pH to understand the effect of minor pH changes on the stability of the protein structure. Future X-ray crystallography analysis could result in further understanding of how SOD1 aggregates which might help produce viable treatments for the familial form of ALS
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