1,262 research outputs found
On the measurement of the Hubble constant in a local low-density universe
Astrophysical observations indicate that the ``Local Universe" has a
relatively lower matter density () than the predictions of the
standard inflation cosmology and the large-scale motions of galaxies which
provide a mean mass density to be very close to unity. In such a local
underdense region the Hubble expansion may not be representative of the global
behaviour. Utilizing an underdense sphere embedded in a flat universe as the
model of our ``Local Universe", we show that the local Hubble constant would be
1.2 -- 1.4 times larger than the global value on scale of Mpc,
depending on the variation of . This may account for the recent
measurements of the unpleasantly large Hubble constant of 80 km/s/Mpc
using the Cepheid variables in the Virgo cluster and the relative distance
between Virgo and Coma cluster and removes the resulted apparent paradox of the
age of our universe.Comment: 9 pages, Latex file, 3 figures available by reques
Application of RetCamâ…¡ in the screening of neonatal fundus disease
AIM: To investigate the safe and reliable examination method for neonatal fundus screening.<p>METHODS: Fundus information of 2 836 neonates performed by RetCamâ…¡ in our hospital from January 1, 2012 to December 31, 2012 were retrospectively analyzed, including 1 625 cases(57.30%)of premature infants which were first examined 1-4 weeks after birth and 1 211 cases(42.70%)of term infants which were first examined within 4 weeks after birth.<p>RESULTS: Totally 454 cases of abnormalfundus were found, including 207 cases(12.74%)of retinopathy of prematurity(ROP), ROPâ… in 118 cases(57%), ROPâ…¡ in 58 cases(28.02%), ROPâ…¢ in 23 cases(11.11%), ROPâ…£ in 8 cases(3.86%), no case of ROPV. A total of 247(20.40%)term infants had abnormal fundus, of which 68 cases(27.53%)were developmental or hereditary disease, retinoblastoma in 1 case(0.40%), retinal hemorrhage in 102 cases(41.30%), retinal exudative changes in 68 cases(27.53%), optic atrophy in 5 cases(2.02%)and optic disc edema in 3 cases(1.21%).<p>CONCLUSION: Neonatal fundus diseases were so various and harmful that early screening should be attended to. Premature infants and term infants with high risk are treated as focus group of fundus screening and RetCamII examination is safe and effective
- …