The Oblique Corrections from Heavy Scalars in Irreducible Representations

The contributions to $S$, $T$, and $U$ from heavy scalars in any irreducible representation of the electroweak gauge group $SU(2)_L\times U(1)_Y$ are obtained. We find that in the case of a heavy scalar doublet there is a slight difference between the $S$ parameter we have obtained and that in previous works.Comment: 6 pages, 2 axodraw figures; minor changes, references update

Waves and instability in a one-dimensional microfluidic array

Motion in a one-dimensional (1D) microfluidic array is simulated. Water droplets, dragged by flowing oil, are arranged in a single row, and due to their hydrodynamic interactions spacing between these droplets oscillates with a wave-like motion that is longitudinal or transverse. The simulation yields wave spectra that agree well with experiment. The wave-like motion has an instability which is confirmed to arise from nonlinearities in the interaction potential. The instability's growth is spatially localized. By selecting an appropriate correlation function, the interaction between the longitudinal and transverse waves is described

Screening, identification and degrading gene assignment of a chrysene-degrading strain

A predominant chrysene-degrading strain named CT was isolated from the activated sludge of Zhenjiang coking plant. The strain was initially identified as Paracoccus aminovorans by the results of morphological observation, physio-biochemical test and 16S rDNA gene sequence analysis. Under the conditions of initial chrysene concentration of 40 mg/l, inoculation amount of 10% (V/V) at pH 7.0 and temperature of 35°C, the degradation efficiency of chrysene by the strain CT reached 85.2% within 8 days. Alkaline lysis was applied to the extract plasmids from strain CT to confirm the location of chrysene-degrading genes. A plasmid, greater than 15 kb, was detected. The transformants obtained the ability to degrade chrysene when the plasmid of strain CT was transformed to competent cell of Escherichia coli DH10B, and could remove 43% of chrysene in the solutions with concentration of 30 mg/l within 8 days. But the mutation lost the ability to degrade chrysene when its plasmid was eliminated by sodium dodecyl sulfonate (SDS) and high temperature. This indicated that the plasmid of strain CT carried chrysene-degrading genes.Key words: Chrysene, degrading strain, Paracoccus, degrading gene,  plasmid

Merger Dynamics of the Pair of Galaxy Clusters -- A399 and A401

Convincing evidence of a past interaction between two rich clusters A399 and A401 was recently found by the X-ray imaging observations. In this paper we examine the structure and dynamics of this pair of galaxy clusters. A mixture-modeling algorithm has been applied to obtain a robust partition into two clusters, which allows us to discuss the virial mass and velocity distribution for each cluster. Assuming that these two clusters follow a linear orbit and they have once experienced a close encounter, we model the binary cluster as a two-body system. As a result, four gravitationally bound solutions are obtained. The recent X-ray observations seem to favor a scenario in which the two clusters with a true separation of $5.4h^{-1}$ Mpc are currently expanding at 583 km/s along the direction with a projection angle of 67.5 degree, and they will reach a maximum extent of $5.65h^{-1}$ Mpc in about $1.0h^{-1}$ Gyr.Comment: 11 pages, including 6 EPS figures and 4 tables, uses chjaa.cls, Accepted by the ChJA

Ultrasmall divergence of laser-driven ion beams from nanometer thick foils

We report on experimental studies of divergence of proton beams from nanometer thick diamond-like carbon (DLC) foils irradiated by an intense laser with high contrast. Proton beams with extremely small divergence (half angle) of 2 degree are observed in addition with a remarkably well-collimated feature over the whole energy range, showing one order of magnitude reduction of the divergence angle in comparison to the results from micrometer thick targets. We demonstrate that this reduction arises from a steep longitudinal electron density gradient and an exponentially decaying transverse profile at the rear side of the ultrathin foils. Agreements are found both in an analytical model and in particle-in-cell simulations. Those novel features make nm foils an attractive alternative for high flux experiments relevant for fundamental research in nuclear and warm dense matter physics.Comment: 11 pages, 5 figure

Prenatal transfer of gut bacteria in Rock pigeon

Vertebrates evolved in concert with bacteria and have developed essential mutualistic relationships. Gut bacteria are vital for the postnatal development of most organs and the immune and metabolic systems and may likewise play a role during prenatal development. Prenatal transfer of gut bacteria is shown in four mammalian species, including humans. For the 92% of the vertebrates that are oviparous, prenatal transfer is debated, but it has been demonstrated in domestic chicken. We hypothesize that also non-domestic birds can prenatally transmit gut bacteria. We investigated this in medium-sized Rock pigeon (Columba livia), ensuring neonates producing fair-sized first faeces. The first faeces of 21 neonate rock pigeons hatched in an incubator, contained a microbiome (bacterial community) the composition of which resembled the cloacal microbiome of females sampled from the same population (N = 5) as indicated by multiple shared phyla, orders, families, and genera. Neonates and females shared 16.1% of the total number of OTUs present (2881), and neonates shared 45.5% of their core microbiome with females. In contrast, the five females shared only 0.3% of the 1030 female OTUs present. These findings suggest that prenatal gut bacterial transfer may occur in birds. Our results support the hypothesis that gut bacteria may be important for prenatal development and present a heritability pathway of gut bacteria in vertebrates

R-parity violation effect on the top-quark pair production at linear colliders

We investigate in detail the effects of the R-parity lepton number violation in the minimal supersymmetric standard model (MSSM) on the top-quark pair production via both $e^--e^+$ and $\gamma-\gamma$ collision modes at the linear colliders. We find that with the present experimental constrained $\rlap/{R}$ parameters, the effect from $\rlap/{R}$ interactions on the processes $e^+e^-\to t\bar{t}$ and $e^+e^- \to \gamma\gamma \to t\bar{t}$ could be significant and may reach -30% and several percent, respectively. Our results show that the $\rlap/{R}$ effects are sensitive to the c.m.s. energy and the relevant $\rlap/{R}$ parameters. However, they are not sensitive to squark and slepton masses when $m_{\tilde{q}} \geq 400 GeV$ (or $m_{\tilde{l}} \geq 300 GeV$) and are almost independent on the $\tan\beta$Comment: Accepted by Phys.Rev.

GPU-based Iterative Cone Beam CT Reconstruction Using Tight Frame Regularization

X-ray imaging dose from serial cone-beam CT (CBCT) scans raises a clinical concern in most image guided radiation therapy procedures. It is the goal of this paper to develop a fast GPU-based algorithm to reconstruct high quality CBCT images from undersampled and noisy projection data so as to lower the imaging dose. For this purpose, we have developed an iterative tight frame (TF) based CBCT reconstruction algorithm. A condition that a real CBCT image has a sparse representation under a TF basis is imposed in the iteration process as regularization to the solution. To speed up the computation, a multi-grid method is employed. Our GPU implementation has achieved high computational efficiency and a CBCT image of resolution 512\times512\times70 can be reconstructed in ~5 min. We have tested our algorithm on a digital NCAT phantom and a physical Catphan phantom. It is found that our TF-based algorithm is able to reconstrct CBCT in the context of undersampling and low mAs levels. We have also quantitatively analyzed the reconstructed CBCT image quality in terms of modulation-transfer-function and contrast-to-noise ratio under various scanning conditions. The results confirm the high CBCT image quality obtained from our TF algorithm. Moreover, our algorithm has also been validated in a real clinical context using a head-and-neck patient case. Comparisons of the developed TF algorithm and the current state-of-the-art TV algorithm have also been made in various cases studied in terms of reconstructed image quality and computation efficiency.Comment: 24 pages, 8 figures, accepted by Phys. Med. Bio