1,083 research outputs found
Computer recommendations for an automatic approach and landing system for V/STOL aircraft. Volume 2 - Equations
Automatic approach and landing system for V/STOL aircraf
Intelligent Reflecting Surface based Passive Information Transmission: A Symbol-Level Precoding Approach
Intelligent reflecting surfaces (IRS) have been proposed as a revolutionary
technology owing to its capability of adaptively reconfiguring the propagation
environment in a cost-effective and hardware-efficient fashion. While the
application of IRS as a passive reflector to enhance the performance of
wireless communications has been widely investigated in the literature, using
IRS as a passive transmitter recently is emerging as a new concept and
attracting steadily growing interest. In this paper, we propose two novel
IRS-based passive information transmission systems using advanced symbol-level
precoding. One is a standalone passive information transmission system, where
the IRS operates as a passive transmitter serving multiple receivers by
adjusting its elements to reflect unmodulated carrier signals. The other is a
joint passive reflection and information transmission system, where the IRS not
only enhances transmissions for multiple primary information receivers (PIRs)
by passive reflection, but also simultaneously delivers additional information
to a secondary information receiver (SIR) by embedding its information into the
primary signals at the symbol level. Two typical optimization problems, i.e.,
power minimization and quality-of-service (QoS) balancing, are investigated for
the proposed IRS-based passive information transmission systems. Simulation
results demonstrate the feasibility of IRS-based passive information
transmission and the effectiveness of our proposed algorithms, as compared to
other benchmark schemes.Comment: 14 pages, 11 figures, major revisio
Seasonal Variations in TemperatureāSuicide Associations across South Korea
South Korea has among the highest rates of suicide in the world, and previous research suggests that suicide frequency increases with anomalously high temperatures, possibly as a result of increased sunshine. However, it is unclear whether this temperatureāsuicide association exists throughout the entire year. Using distributed lag nonlinear modeling, which effectively controls for nonlinear and delayed effects, we examine temperatureāsuicide associations for both a warm season (AprilāSeptember) and a cool season (OctoberāMarch) for three cities across South Korea: Seoul, Daegu, and Busan. We find consistent, statistically significant, mostly linear relationships between relative risk of suicide and daily temperature in the cool season but few associations in the warm season. This seasonal signal of statistically significant temperatureāsuicide associations only in the cool season exists among all age segments, but especially for those 35 and older, along with both males and females. We further use distributed lag nonlinear modeling to examine cloud coverāsuicide associations and find few significant relationships. This result suggests that that high daily temperatures in the cool season, and not exposure to sun, are responsible for the strong temperatureāsuicide associations found in South Korea
Super-Kamiokande 0.07 eV Neutrinos in Cosmology: Hot Dark Matter and the Highest Energy Cosmic Rays
Relic neutrinos with mass in the range indicated by Super-Kamiokande results
if neutrino masses are hierarchial (about 0.07 eV) are many times deemed too
light to be cosmologically relevant. Here we remark that these neutrinos may
significantly contribute to the dark matter of the Universe (with a large
lepton asymmetry ) and that their existence might be revealed by the
spectrum of ultra high energy cosmic rays (maybe even in the absence of a large
).Comment: Talk given at the ``4th International Symposium on Sources and
Detection of Dark Matter in the Universe", February 23-25, 2000, Marina del
Rey, CA (to appear in its proceedings) and at the ``Cosmic Genesis and
Fundamental Physics" workshop, October 28-30, 1999, Sonoma State University,
Santa Rosa, CA. (8 p. 1 fig.
Do Quiescent and Active Galaxies Have Different M_(BH)-Ļ* Relations?
To investigate the validity of the assumption that quiescent galaxies and active galaxies follow the same black hole mass (M_BH)-stellar velocity dispersion (Ļ*) relation, as required for the calibration of M_BH estimators for broad line active galactic nuclei (AGNs), we determine and compare the M_BH-Ļ* relations, respectively, for quiescent and active galaxies. For the quiescent galaxy sample, composed of 72 dynamical M_BH measurements, we update Ļ* for 28 galaxies using homogeneous H-band measurements that are corrected for galaxy rotation. For active galaxies, we collect 25 reverberation-mapped AGNs and improve Ļ* measurement for two objects. Combining the two samples, we determine the virial factor f, first by scaling the active galaxy sample to the M_BH-Ļ* relation of quiescent galaxies, and second by simultaneously fitting the quiescent and active galaxy samples, as f=5.1^(+1.5)_(-1.1) and f=5.9^(+2.1)_(-1.5), respectively. The M_BH-Ļ* relation of active galaxies appears to be shallower than that of quiescent galaxies. However, the discrepancy is caused by a difference in the accessible M_BH distribution at given Ļ*, primarily due to the difficulty of measuring reliable stellar velocity dispersion for the host galaxies of luminous AGNs. Accounting for the selection effects, we find that active and quiescent galaxies are consistent with following intrinsically the same M_BH-Ļ* relation
Calibrating Stellar Velocity Dispersions Based on Spatially Resolved H-band Spectra for Improving the M_(BH)-Ļ_* Relation
To calibrate stellar velocity dispersion measurements from optical and near-IR stellar lines, and to improve the black hole mass (M_(BH))-stellar velocity dispersion (Ļ_*) relation, we measure Ļ_* based on high-quality H-band spectra for a sample of 31 nearby galaxies, for which dynamical M_(BH) is available in the literature. By comparing velocity dispersions measured from stellar lines in the H-band with those measured from optical stellar lines, we find no significant difference, suggesting that optical and near-IR stellar lines represent the same kinematics and that dust effect is negligible for early-type galaxies. Based on the spatially resolved rotation and velocity dispersion measurements along the major axis of each galaxy, we find that a rotating stellar disk is present for 80% of galaxies in the sample. For galaxies with a rotation component, Ļ_* measured from a single aperture spectrum can vary by up to ~20%, depending on the size of the adopted extraction aperture. To correct for the rotational broadening, we derive luminosity-weighted Ļ_* within the effective radius of each galaxy, providing uniformly measured velocity dispersions to improve the M_(BH)-Ļ_* relation
Growth of ultra-uniform graphene using a Ni/W bilayer metal catalyst
We investigated a bilayer catalyst system consisting of polycrystalline Ni and W films for growing mono-layer graphene over large areas. Highly uniform graphene was grown on Ni/W bilayer film with 100% coverage. The graphene grown on Ni/W bilayer film and transferred onto an insulating substrate exhibited average hole and electron mobilities of 727 and 340 cm(2)V(-1)s(-1), respectively. A probable growth mechanism is proposed based on X-ray diffractometry and transmission electron microscopy, which suggests that the reaction between diffused carbon and tungsten atoms results in formation of tungsten carbides. This reaction allows the control of carbon precipitation and prevents the growth of non-uniform multilayer graphene on the Ni surface; this has not been straightforwardly achieved before. These results could be of importance in better understanding mono-layer graphene growth, and suggest a facile fabrication route for electronic applications. (C) 2015 AIP Publishing LLCopen0
Improved protein arrays for quantitative systems analysis of the dynamics of signaling pathway interactions
An improved version of quantitative protein array platform utilizing linear Quantum dot signaling for systematically measuring protein levels and phosphorylation states is presented. The signals are amplified linearly by a confocal laser Quantum dot scanner resulting in ~1000-fold more sensitivity than traditional Western blots, but are not linear by the enzyme-based amplification. Software is developed to facilitate the quantitative readouts of signaling network activities. Kinetics of EGFRvIII mutant signaling was analyzed to quantify cross-talks between EGFR and other signaling pathways
Reactive case-detection of malaria in Pailin Province, Western Cambodia: lessons from a year-long evaluation in a pre-elimination setting.
BACKGROUND: As momentum towards malaria elimination grows, strategies are being developed for scale-up in elimination settings. One prominent strategy, reactive case detection (RACD), involves screening and treating individuals living in close proximity to passively detected, or "index" cases. This study aims to use RACD to quantify Plasmodium parasitaemia in households of index cases, and identify risk factors for infection; these data could inform reactive screening approaches and identify target risk groups. METHODS: This study was conducted in the Western Cambodian province of Pailin between May 2013 and March 2014 among 440 households. Index participants/index cases (n = 270) and surrounding households (n = 110) were screened for Plasmodium infection with rapid diagnostic tests (RDT), microscopy and real-time polymerase chain reaction (PCR). Participants were interviewed to identify risk factors. A comparison group of 60 randomly-selected households was also screened, to compare infection levels of RACD and non-RACD households. In order to identify potential risk factors that would inform screening approaches and identify risk groups, multivariate logistic regression models were applied. RESULTS: Nine infections were identified in households of index cases (RACD approach) through RDT screening of 1898 individuals (seven Plasmodium vivax, two Plasmodium falciparum); seven were afebrile. Seventeen infections were identified through PCR screening of 1596 individuals (15 P. vivax, and 22 % P. falciparum/P. vivax mixed infections). In the control group, 25 P. falciparum infections were identified through PCR screening of 237 individuals, and no P. vivax was found. Plasmodium falciparum infection was associated with fever (p = 0.013), being a member of a control household (p ā¤ 0.001), having a history of malaria infection (p = 0.041), and sleeping without a mosquito net (p = 0.011). Significant predictors of P. vivax infection, as diagnosed by PCR, were fever (p = 0.058, borderline significant) and history of malaria infection (p ā¤ 0.001). CONCLUSION: This study found that RACD identified very few secondary infections when targeting index and neighbouring households for screening. The results suggest RACD is not appropriate, where exposure to malaria occurs away from the community, and there is a high level of treatment-seeking from the private sector. Piloting RACD in a range of transmission settings would help to identify the ideal environment for feasible and effective reactive screening methods
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