2,223 research outputs found
A Second-order bias model for the Logarithmic Halo Mass Density
We present an analytic model for the local bias of dark matter halos in a
LCDM universe. The model uses the halo mass density instead of the halo number
density and is searched for various halo mass cuts, smoothing lengths, and
redshift epoches. We find that, when the logarithmic density is used, the
second-order polynomial can fit the numerical relation between the halo mass
distribution and the underlying matter distribution extremely well. In this
model the logarithm of the dark matter density is expanded in terms of log halo
mass density to the second order. The model remains excellent for all halo mass
cuts (from M_{cut}=3\times10^{11}3\times10^{12}h^{-1}M_{\odot}R=5h^{-1}50h^{-1}$Mpc), and redshift ranges
(from z=0 to 1.0) considered in this study. The stochastic term in the relation
is found not entirely random, but a part of the term can be determined by the
magnitude of the shear tensor.Comment: 8 pages, 7 figures, accepted for publication on Ap
Extraskeletal chondroma of the fallopian tube.
Extraskeletal chondroma can occur in the hands, feet, head and neck. This tumor usually presents as a small solitary nodule. The histogenesis of the tumor is controversial, but some have suggested a metaplastic origin. Chondroma of the fallopian tube is very rare. There is only one report in English literature. The origin of this tumor can be subcoelomic mesenchyme of the tubal serosa or mesenchyme of the myosalpinx. We describe a case of chondroma arising from the serosal surface of the fallopian tube with a review of literature. A 30-yr-old woman visited hospital due to left adnexal mass. On operating finding, 2 x 3 cm sized nodular mass was noted on the left tubal serosal area. The excised mass showed multilobulated appearance covered with thin fibrous membrane. The cut surface was solid, grayish yellow, and myxoid with a focal gelatinous area. The microscopic finding showed islands and elongated lobules of mature benign cartilage without cytologic atypia
Simultaneous dual-frequency radio observations of S5 0716+714: A search for intraday variability with the Korean VLBI Network
This study aims to search for the existence of intraday variability (IDV) of
BL Lac object S5 0716+714 at high radio frequencies for which the interstellar
scintillation effect is not significant. Using the 21-meter radio telescope of
the Korean VLBI Network (KVN), we present results of multi-epoch simultaneous
dual-frequency radio observations. Single-dish observations of S5 0716+714 were
simultaneously conducted at 21.7 GHz (K-band) and 42.4 GHz (Q-band), with a
high cadence of 30-60 minute intervals.We observed four epochs between December
2009 and June 2010. Over the whole set of observation epochs, S5 0716+714
showed significant inter-month variations in flux density at both the K- and
Q-bands, with modulation indices of approximately 19% for the K-band and
approximately 36% for the Q-band. In all epochs, no clear intraday variability
was detected at either frequency. The source shows monotonic flux density
increase in epochs 1 and 3 and monotonic flux density decrease in epochs 2 and
4. In the flux density increasing phases, the flux densities at the Q-band
increase more rapidly. In the decreasing phase, no significant flux density
difference is seen at the two frequencies. The situation could be different
close to flux density peaks that we did not witness in our observations. We
find an inverted spectrum with mean spectral indices of -0.57+-0.13 in epoch 1
and -0.15+-0.11 in epoch 3. On the other hand, we find relatively steep indices
of +0.24+-0.14 and +0.17+-0.18 in epochs 2 and 4, respectively. We conclude
that the frequency dependence of the variability and the change of the spectral
index are caused by source-intrinsic effects rather than by any extrinsic
scintillation effect.Comment: 6 pages and 4 figures and 4 table
Development and characterization of nine polymorphic microsatellite markers in the seven-spotted lady beetle, Coccinella septempunctata (Coleoptera: Coccinellidae)
In this study, nine microsatellite loci were isolated and characterized from the seven-spotted lady beetle, Coccinella septempunctata (Coleoptera: Coccinellidae). The loci were validated and characterized using 20 samples collected from five Korean localities. These results indicate that some loci were highly variable in terms of number of alleles (2 to 13), heterozygosity (0.10 to 0.40), and polymorphic information content (0.31 to 0.85). These microsatellite markers will be very valuable for population genetic studies of C. septempunctata.Key words: Seven-spotted lady beetle, Coccinella septempunctata, microsatellite Deoxyribonucleic acid (DNA)
Multiple Sclerosis and Peripheral Multifocal Demyelinating Neuropathies Occurring in a Same Patient
The co-occurrence of multiple sclerosis and peripheral demyelinating neuropathy is rare. It has been disputed whether these are pathologically related or coincidental findings. We report a 36-year-old woman who presented with diplopia, right facial palsy and left-sided weakness. Brain magnetic resonance imaging showed a lesion indicative of central demyelinating disease. Nerve conduction studies revealed peripheral multifocal demyelinating neuropathies. We suggest that the central and the peripheral lesions may be continua of a demyelinating process
Ubiquitous testing using tablets: its impact on medical student perceptions of and engagement in learning
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Urinary 8-hydroxy-2'-deoxyguanosine as a biomarker of oxidative DNA damage in workers exposed to fine particulates.
Residual oil fly ash (ROFA) is a chemically complex mixture of compounds, including metals that are potentially carcinogenic because of their ability to cause oxidative injury. In this study, we investigated the association between exposure to particulate matter with an aerodynamic mass median diameter ≤ 2.5 micro m (PM2.5) and oxidative DNA damage and repair, as indicated by urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) concentrations, in a group of boilermakers exposed to ROFA and metal fumes. Twenty workers (50% smokers) were monitored for 5 days during an overhaul of oil-fired boilers. The median occupational PM2.5 8-hr time-weighted average was 0.44 mg/m3 (25th-75th percentile, 0.29-0.76). The mean ± SE creatinine-adjusted 8-OHdG levels were 13.26 ± 1.04 micro μg/g in urine samples collected pre-workshift and 15.22 ± 0.99 micro μg/g in the post-workshift samples. The urinary 8-OHdG levels were significantly greater in the post-workshift samples than in the pre-workshift samples (p = 0.02), after adjusting for urinary cotinine levels, chronic bronchitis status, and age. Linear mixed models indicated a significant exposure-response association between PM2.5 exposure and urinary 8-OHdG levels (p = 0.03). Each 1-mg/m3 incremental increase in PM2.5 exposure was associated with an increase of 1.67 micro μg/g (95% confidence interval, 0.21-3.14) in 8-OHdG levels. PM2.5 vanadium, manganese, nickel, and lead exposures also were positively associated with 8-OHdG levels (p ≤ 0.05). This study suggests that a relatively young and healthy cohort of boilermakers may experience an increased risk of developing oxidative DNA injury after exposure to high levels of metal-containing particulate matter
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