107 research outputs found
First Detection of NaI D lines in High-Redshift Damped Lyman-alpha Systems
A Near-infrared (1.18-1.35 micron) high-resolution spectrum of the
gravitationally-lensed QSO APM 08279+5255 was obtained with the IRCS mounted on
the Subaru Telescope using the AO system. We detected strong NaI D 5891,5897
doublet absorption in high-redshift DLAs at z=1.062 and 1.181, confirming the
presence of NaI, which was first reported for the rest-frame UV NaI
3303.3,3303.9 doublet by Petitjean et al. This is the first detection of NaI D
absorption in a high-redshift (z>1) DLA. In addition, we detected a new NaI
component in the z=1.062 DLA and four new components in the z=1.181 DLA. Using
an empirical relationship between NaI and HI column density, we found that all
"components" have large HI column density, so that each component is classified
as DLA absorption. We also detected strong NaI D absorption associated with a
MgII system at z=1.173. Because no other metal absorption lines were detected
in this system at the velocity of the NaI absorption in previously reported
optical spectra (observed 3.6 years ago), we interpret this NaI absorption
cloud probably appeared in the line of sight toward the QSO after the optical
observation. This newly found cloud is likely to be a DLA based upon its large
estimated HI column density. We found that the N(NaI)/N(CaII) ratios in these
DLAs are systematically smaller than those observed in the Galaxy; they are
more consistent with the ratios seen in the Large Magellanic Cloud. This is
consistent with dust depletion generally being smaller in lower metallicity
environments. However, all five clouds of the z=1.181 system have a high
N(NaI)/N(CaII) ratio, which is characteristic of cold dense gas. We tentatively
suggest that the host galaxy of this system may be the most significant
contributor to the gravitational-lens toward APM 08279+5255.Comment: 22 pages, 6 Postscript figures, 3 tables, ApJ in press (Vol.643, 2
June 2006
A Naturally Occurring Canine Model of Autosomal Recessive Congenital Stationary Night Blindness
Congenital stationary night blindness (CSNB) is a non-progressive, clinically and genetically heterogeneous disease of impaired night vision. We report a naturally-occurring, stationary, autosomal recessive phenotype in beagle dogs with normal daylight vision but absent night vision. Affected dogs had normal retinas on clinical examination, but showed no detectable rod responses. They had ânegative-typeâ mixed rod and cone responses in full-field ERGs. Their photopic long-flash ERGs had normal OFF-responses associated with severely reduced ON-responses. The phenotype is similar to the Schubert-Bornschein form of complete CSNB in humans. Homozygosity mapping ruled out most known CSNB candidates as well as CACNA2D4 and GNB3. Three remaining genes were excluded based on sequencing the open reading frame and intron-exon boundaries (RHO, NYX), causal to a different form of CSNB (RHO) or X-chromosome (NYX, CACNA1F) location. Among the genes expressed in the photoreceptors and their synaptic terminals, and mGluR6 cascade and modulators, reduced expression of GNAT1, CACNA2D4 and NYX was observed by qRT-PCR in both carrier (n = 2) and affected (n = 2) retinas whereas CACNA1F was down-regulated only in the affecteds. Retinal morphology revealed normal cellular layers and structure, and electron microscopy showed normal rod spherules and synaptic ribbons. No difference from normal was observed by immunohistochemistry (IHC) for antibodies labeling rods, cones and their presynaptic terminals. None of the retinas showed any sign of stress. Selected proteins of mGluR6 cascade and its modulators were examined by IHC and showed that PKCα weakly labeled the rod bipolar somata in the affected, but intensely labeled axonal terminals that appeared thickened and irregular. Dendritic terminals of ON-bipolar cells showed increased Goα labeling. Both PKCα and Goα labeled the more prominent bipolar dendrites that extended into the OPL in affected but not normal retinas. Interestingly, RGS11 showed no labeling in the affected retina. Our results indicate involvement of a yet unknown gene in this canine model of complete CSNB
The Origin of the Charge Ordering and Its Relevance to Superconductivity in -(BEDT-TTF)X: The Effect of the Fermi Surface Nesting and the Distant Electron-Electron Interactions
The origin of the charge ordering in organic compounds -(BEDT-TTF) ((SCN), Tl,Rb,Co, Cs,Zn) is studied using an extended
Hubbard model. Calculating the charge susceptibility within random phase
approximation (RPA), we find that the charge
ordering observed at relatively high temperatures can be considered as a
consequence of a cooperation between the Fermi surface nesting, controlled by
the hopping integral in the direction, and the electron-electron
interactions, where the distant (next nearest neighbor) interactions that have
not been taken into account in most of the previous studies play an important
role.Mean field analysis at T=0 also supports the RPA results, and further
shows that in the charge ordered state, some portions of the Fermi
surface remain ungapped and are nested with a nesting vector close to the
modulation wave vector of the horizontal stripe ordering observed at low
temperatures in (SCN). We further study the possibility of
superconductivity by taking into account the distant off-site repulsions and
the band structure corresponding to I, in which superconductivity is
experimentally observed. We find that there is a close competition between
-wave-like singlet pairing and -wave-like triplet pairing due
to a cooperation between the charge and the spin fluctuations. The present
analysis provides a possible unified understanding of the experimental phase
diagram of the -(BEDT-TTF) family, ranging from a charge ordered
insulator to a superconductor.Comment: 13 pages, 18 figures (Figs.5,6,7,14,15,18 compressed using jpeg2ps
Metal-insulator transition in the two-orbital Hubbard model at fractional band fillings: Self-energy functional approach
We investigate the infinite-dimensional two-orbital Hubbard model at
arbitrary band fillings. By means of the self-energy functional approach, we
discuss the stability of the metallic state in the systems with same and
different bandwidths. It is found that the Mott insulating phases are realized
at commensurate band fillings. Furthermore, it is clarified that the orbital
selective Mott phase with one orbital localized and the other itinerant is
stabilized even at fractional band fillings in the system with different
bandwidths.Comment: 7 pages, 10 figure
Pairing Symmetry Competition in Organic Superconductors
A review is given on theoretical studies concerning the pairing symmetry in
organic superconductors. In particular, we focus on (TMTSF)X and
-(BEDT-TTF)X, in which the pairing symmetry has been extensively
studied both experimentally and theoretically. Possibilities of various pairing
symmetry candidates and their possible microscopic origin are discussed. Also
some tests for determining the actual pairing symmtery are surveyed.Comment: 16 pages, 8 figures, to be published in J. Phys. Soc. Jpn., special
issue on "Organic Conductors
Associations between the orexin (hypocretin) receptor 2 gene polymorphism Val308Ile and nicotine dependence in genome-wide and subsequent association studies
Impact of the HCRTR2 gene risk variant on schizotypal personality traits (meanĂąÂÂĂÄ
ĂąÂÂSD). (DOC 54 kb
Search for dark matter produced in association with bottom or top quarks in âs = 13 TeV pp collisions with the ATLAS detector
A search for weakly interacting massive particle dark matter produced in association with bottom or top quarks is presented. Final states containing third-generation quarks and miss- ing transverse momentum are considered. The analysis uses 36.1 fbâ1 of protonâproton collision data recorded by the ATLAS experiment at âs = 13 TeV in 2015 and 2016. No significant excess of events above the estimated backgrounds is observed. The results are in- terpreted in the framework of simplified models of spin-0 dark-matter mediators. For colour- neutral spin-0 mediators produced in association with top quarks and decaying into a pair of dark-matter particles, mediator masses below 50 GeV are excluded assuming a dark-matter candidate mass of 1 GeV and unitary couplings. For scalar and pseudoscalar mediators produced in association with bottom quarks, the search sets limits on the production cross- section of 300 times the predicted rate for mediators with masses between 10 and 50 GeV and assuming a dark-matter mass of 1 GeV and unitary coupling. Constraints on colour- charged scalar simplified models are also presented. Assuming a dark-matter particle mass of 35 GeV, mediator particles with mass below 1.1 TeV are excluded for couplings yielding a dark-matter relic density consistent with measurements
Use of the index of pulmonary vascular disease for predicting long-term outcome of pulmonary arterial hypertension associated with congenital heart disease
AimsLimited data exist on risk factors for the long-term outcome of pulmonary arterial hypertension (PAH) associated with congenital heart disease (CHD-PAH). We focused on the index of pulmonary vascular disease (IPVD), an assessment system for pulmonary artery pathology specimens. The IPVD classifies pulmonary vascular lesions into four categories based on severity: (1) no intimal thickening, (2) cellular thickening of the intima, (3) fibrous thickening of the intima, and (4) destruction of the tunica media, with the overall grade expressed as an additive mean of these scores. This study aimed to investigate the relationship between IPVD and the long-term outcome of CHD-PAH.MethodsThis retrospective study examined lung pathology images of 764 patients with CHD-PAH aged <20 years whose lung specimens were submitted to the Japanese Research Institute of Pulmonary Vasculature for pulmonary pathological review between 2001 and 2020. Clinical information was collected retrospectively by each attending physician. The primary endpoint was cardiovascular death.ResultsThe 5-year, 10-year, 15-year, and 20-year cardiovascular death-free survival rates for all patients were 92.0%, 90.4%, 87.3%, and 86.1%, respectively. The group with an IPVD of â„2.0 had significantly poorer survival than the group with an IPVD <2.0 (Pâ=â.037). The Cox proportional hazards model adjusted for the presence of congenital anomaly syndromes associated with pulmonary hypertension, and age at lung biopsy showed similar results (hazard ratio 4.46; 95% confidence interval: 1.45â13.73; Pâ=â.009).ConclusionsThe IPVD scoring system is useful for predicting the long-term outcome of CHD-PAH. For patients with an IPVD of â„2.0, treatment strategies, including choosing palliative procedures such as pulmonary artery banding to restrict pulmonary blood flow and postponement of intracardiac repair, should be more carefully considered
- âŠ