128 research outputs found
Obscured Binary Quasar Cores in SDSS J104807.74+005543.5?
We report the discovery of a possible close binary system of quasars in SDSS
J1048+0055. The [OIII]4959,5007 emission lines are clearly double-peaked, and
two discrete radio sources with a projected physical separation of ~20 pc are
found in the VLBA milliarcsec resolution image at 8.4 GHz. Each of the [O
III]4959,5007 doublets and Hbeta can be well modelled by two Gaussians and the
line ratio, [O III]5007/Hbeta ~7, is typical of Seyfert 2 galaxies. No broad
component of Hbeta was detected and its [O III]5007 luminosity, L_[OIII] ~ 9.2
times 10^42 erg s^-1, is comparable to luminous quasars and is a few ten times
more luminous than typical Seyfert galaxies. One natural interpretation is that
SDSS J1048+0055 contains two close quasar-like nuclei and the BLR around them
are obscured. Other possible models are also discussed. We suggest that
double-peaked narrow emission line profile may be an effective way of selecting
candidates of binary black holes with intermediate separation
Assessing Junior Faculty Research Productivity in the IS Field: Recommendations for Promotion and Tenure Standards for Asian Schools
We gathered information about junior faculty research productivity in the information systems (IS) field in North America and in a set of top Asian schools. Our work complements prior studies on IS faculty research productivity in several ways. First, we focused on junior faculty research productivity, which refers to publication records of current tenure-track assistant professors. To provide statistics with a greater coverage of IS researchers, we also collected information about the pre-tenure publication records of associate professors. Second, we covered IS researchers who obtained their doctoral degrees in or after the year 2000 and counted their publications until 2013 to provide the most up-to-date information about junior faculty research productivity. Third, we collected information about IS researchers’ publications in leading IS journals (based on the AIS Senior Scholar basket of journals) and in elite broader business journals (based on the Financial Times list and UT Dallas list). Finally, examining junior faculty research productivity in the IS field in Asian schools and in North America enabled us to provide recommendations for promotion and tenure standards for Asian schools in light of the research productivity and tenure standards in North America
Status Processes in Permanent Work Groups
This WP was published by Cohen and Zhou (1991).The research for this paper was supported by the National Science Foundation. The analysis was funded under N.S.F. grant number SES-8520248, Division of Social and Economic Sciences. The data were collected under N.S.F. Grant #ISI-8304340, Division of Industrial Science and Technological Innovation
High resolution fiber optic surface plasmon resonance sensors with single-sided gold coatings
The surface plasmon resonance (SPR) performance of gold coated tilted fiber Bragg gratings (TFBG) at near infrared wavelengths is evaluated as a function of the angle between the tilt plane orientation and the direction of single- and double-sided, nominally 50 nm-thick gold metal depositions. Scanning electron microscope images show that the coating are highly non-uniform around the fiber circumference, varying between near zero and 50 nm. In spite of these variations, the experimental results show that the spectral signature of the TFBG-SPR sensors is similar to that of simulations based on perfectly uniform coatings, provided that the depositions are suitably oriented along the tilt plane direction. Furthermore, it is shown that even a (properly oriented) single-sided coating (over only half of the fiber circumference) is sufficient to provide a theoretically perfect SPR response with a bandwidth under 5 nm, and 90% attenuation. Finally, using a pair of adjacent TFBG resonances within the SPR response envelope, a power detection scheme is used to demonstrate a limit of detection of 3 Ă— 10-6 refractive index units
Compact optical fiber 3D shape sensor based on a pair of orthogonal tilted fiber bragg gratings
In this work, a compact fiber-optic 3D shape sensor consisting of two serially connected 2° tilted fiber Bragg gratings (TFBGs) is proposed, where the orientations of the grating planes of the two TFBGs are orthogonal. The measurement of the reflective transmission spectrum from the pair of TFBGs was implemented by Fresnel reflection of the cleaved fiber end. The two groups of cladding mode resonances in the reflection spectrum respond differentially to bending, which allows for the unique determination of the magnitude and orientation of the bend plane (i.e. with a ± 180 degree uncertainty). Bending responses ranging from -0.33 to + 0.21 dB/m -1 (depending on orientation) are experimentally demonstrated with bending from 0 to 3.03 m -1. In the third (axial) direction, the strain is obtained directly by the shift of the TFBG Bragg wavelengths with a sensitivity of 1.06 pm/με
Measuring charge distribution of molecular cations by atomic Coulomb probe microscope
Imaging the charge distributions and structures of molecules and clusters
will promote the understanding of the dynamics of the quantum system. Here, we
report a method by using an Ar atom as a tip to probe the charge distributions
of benzene (Bz) cations in gas phase. Remarkably, the measured charge
distributions of Bz cation (QH =0.204,QC=-0.037)and dication (QH
=0.248,QC=0.0853)agree well with the calculated Mulliken distributions,and the
structures of Bz dimer is reconstructed by using the measured charge
distributions. The structures of two Bz dimer isomers (T-shaped and PD isomers)
can be resolved from the measured inter-molecular potential V(R) between two Bz
ions, and the structures of Bz dimer agree well with the theoretical
predictions.Comment: 7 pages, 3 Figure
T-Bet and Eomes Regulate the Balance between the Effector/Central Memory T Cells versus Memory Stem Like T Cells
Memory T cells are composed of effector, central, and memory stem cells. Previous studies have implicated that both T-bet and Eomes are involved in the generation of effector and central memory CD8 T cells. The exact role of these transcription factors in shaping the memory T cell pool is not well understood, particularly with memory stem T cells. Here, we demonstrate that both T-bet or Eomes are required for elimination of established tumors by adoptively transferred CD8 T cells. We also examined the role of T-bet and Eomes in the generation of tumor-specific memory T cell subsets upon adoptive transfer. We showed that combined T-bet and Eomes deficiency resulted in a severe reduction in the number of effector/central memory T cells but an increase in the percentage of CD62LhighCD44low Sca-1+ T cells which were similar to the phenotype of memory stem T cells. Despite preserving large numbers of phenotypic memory stem T cells, the lack of both of T-bet and Eomes resulted in a profound defect in antitumor memory responses, suggesting T-bet and Eomes are crucial for the antitumor function of these memory T cells. Our study establishes that T-bet and Eomes cooperate to promote the phenotype of effector/central memory CD8 T cell versus that of memory stem like T cells. © 2013 Li et al
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