3,112 research outputs found
3D Location of Circular and Spherical Features by Monocular Model-Based Vision
This paper addresses the mathematics for using monocular model-based vision to find the 3-D positions of circular and spherical model features, and, for the circular case, orientations as well. Monocular model-based vision here refers to the use of a single projective image of modeled objects to solve for the 3-D positions and orientations of the objects in the scene. The mathematics for solving 3-dimensional position and orientation of the object from matched model and image points/lines features are well known. However, no known paper addresses spherical features arid very few papers address the mathematics involving circular model features. This paper describes a novel closed-formed solution for the 3-D position and orientation of a circular features and the 3-D position of a spherical feature. The number of solutions for the circular case is found to be two in general, but there is only one solution when the surface normal of the circular feature passes through the center of projection. There is only one solution for the circular case. Advantages of this method are: (1) Handles spherical as well as circular features. (2) Closed-form solution. (3) Gives only the necessary number of solutions (no redundant solutions). (4) Simple mathematics involving 3-D analytic Geometry. (5) Geometrically intuitive
The phylogenetically-related pattern recognition receptors EFR and XA21 recruit similar immune signaling components in monocots and dicots
During plant immunity, surface-localized pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs). The transfer of PRRs between plant species is a promising strategy for engineering broad-spectrum disease resistance. Thus, there is a great interest in understanding the mechanisms of PRR-mediated resistance across different plant species. Two well-characterized plant PRRs are the leucine-rich repeat receptor kinases (LRR-RKs) EFR and XA21 from Arabidopsis thaliana (Arabidopsis) and rice, respectively. Interestingly, despite being evolutionary distant, EFR and XA21 are phylogenetically closely related and are both members of the sub-family XII of LRR-RKs that contains numerous potential PRRs. Here, we compared the ability of these related PRRs to engage immune signaling across the monocots-dicots taxonomic divide. Using chimera between Arabidopsis EFR and rice XA21, we show that the kinase domain of the rice XA21 is functional in triggering elf18-induced signaling and quantitative immunity to the bacteria Pseudomonas syringae pv. tomato (Pto) DC3000 and Agrobacterium tumefaciens in Arabidopsis. Furthermore, the EFR:XA21 chimera associates dynamically in a ligand-dependent manner with known components of the EFR complex. Conversely, EFR associates with Arabidopsis orthologues of rice XA21-interacting proteins, which appear to be involved in EFR-mediated signaling and immunity in Arabidopsis. Our work indicates the overall functional conservation of immune components acting downstream of distinct LRR-RK-type PRRs between monocots and dicots
Calibration and Irradiation Study of the BGO Background Monitor for the BEAST II Experiment
Beam commissioning of the SuperKEKB collider began in 2016. The Beam Exorcism
for A STable experiment II (BEAST II) project is particularly designed to
measure the beam backgrounds around the interaction point of the SuperKEKB
collider for the Belle II experiment. We develop a system using bismuth
germanium oxide (BGO) crystals with optical fibers connecting to a multianode
photomultiplier tube (MAPMT) and a field-programmable gate array (FPGA)
embedded readout board for monitoring the real-time beam backgrounds in BEAST
II. The overall radiation sensitivity of this system is estimated to be
Gy/ADU (analog-to-digital unit) with the standard
10 m fibers for transmission and the MAPMT operating at 700 V. Our -ray
irradiation study of the BGO system shows that the exposure of BGO crystals to
Co -ray doses of 1 krad has led to immediate light output
reductions of 25--40%, and the light outputs further drop by 30--45% after the
crystals receive doses of 2--4 krad. Our findings agree with those of the
previous studies on the radiation hard (RH) BGO crystals grown by the low
thermal gradient Czochralski (LTG Cz) technology. The absolute dose from the
BGO system is also consistent with the simulation, and is estimated to be about
1.18 times the equivalent dose. These results prove that the BGO system is able
to monitor the background dose rate in real time under extreme high radiation
conditions. This study concludes that the BGO system is reliable for the beam
background study in BEAST II
Angular Dependence of X-ray Absorption Spectrum for Field-aligned Fe-based Superconductors
Anisotropic Fe K-edge and As K-edge X-ray absorption near edge spectrum
(XANES) measurements on superconducting (T_c = 52 K)
(Sm_{0.95}La_{0.05})FeAs(O_{0.85}F_{0.15}) field-aligned microcrystalline
powder are presented. The angular dependence of Fe pre-edge peak (dipole
transition of Fe-1s electrons to Fe-3d/As-4p hybrid bands) relative to the
tetragonal ab-plane of aligned powder indicates larger density of state (DOS)
along the c-axis, and is consistent with the LDA band structure calculation.
The anisotropic Fe K-edge spectra exhibit a chemical shift to lower energy
compared to FeO which are closely related to the itinerant character of
Fe^{2+}-3d^6 orbitals. The anisotropic As K-edge spectra are more or less the
mirror images of Fe K-edge due to the symmetrical Fe-As hybridiztion in the
FeAs layer. Angular dependence of As main peak (dipole transition of As-1s
electrons to higher energy hybrid bands) was observed suggesting character of
As-4d e_g orbitals.Comment: 4 pages, 6 figures, accepted 9/11/2009 Physical Review B (B15
On D3-brane Dynamics at Strong Warping
We study the dynamics of a D3 brane in generic IIB warped compactifications,
using the Hamiltonian formulation discussed in arXiv:0805.3700 [hep-th]. Taking
into account of both closed and open string fluctuations, we derive the warped
Kahler potential governing the motion of a probe D3 brane. By including the
backreaction of D3, we also comment on how the problem of defining a
holomorphic gauge coupling on wrapped D7 branes in warped background can be
resolved.Comment: 19 pages, No figure
Bose--Einstein Condensation in the Large Deviations Regime with Applications to Information System Models
We study the large deviations behavior of systems that admit a certain form
of a product distribution, which is frequently encountered both in Physics and
in various information system models. First, to fix ideas, we demonstrate a
simple calculation of the large deviations rate function for a single
constraint (event). Under certain conditions, the behavior of this function is
shown to exhibit an analogue of Bose--Einstein condensation (BEC). More
interestingly, we also study the large deviations rate function associated with
two constraints (and the extension to any number of constraints is conceptually
straightforward). The phase diagram of this rate function is shown to exhibit
as many as seven phases, and it suggests a two--dimensional generalization of
the notion of BEC (or more generally, a multi--dimensional BEC). While the
results are illustrated for a simple model, the underlying principles are
actually rather general. We also discuss several applications and implications
pertaining to information system models
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