1,190 research outputs found
On the particle paths and the stagnation points in small-amplitude deep-water waves
In order to obtain quite precise information about the shape of the particle
paths below small-amplitude gravity waves travelling on irrotational deep
water, analytic solutions of the nonlinear differential equation system
describing the particle motion are provided. All these solutions are not closed
curves. Some particle trajectories are peakon-like, others can be expressed
with the aid of the Jacobi elliptic functions or with the aid of the
hyperelliptic functions. Remarks on the stagnation points of the
small-amplitude irrotational deep-water waves are also made.Comment: to appear in J. Math. Fluid Mech. arXiv admin note: text overlap with
arXiv:1106.382
Substitution induced pinning in MgB_2 superconductor doped with SiC nano-particles
By doping MgB_2 superconductor with SiC nano-particles, we have successfully
introduced pinning sites directly into the crystal lattice of MgB_2 grains
(intra-grain pinning). It became possible due to the combination of
counter-balanced Si and C co-substitution for B, leading to a large number of
intra-granular dislocations and the dispersed nano-size impurities induced by
the substitution. The magnetic field dependence of the critical current density
was significantly improved in a wide temperature range, whereas the transition
temperature in the sample MgB_2(SiC)_x having x = 0.34, the highest doping
level prepared, dropped only by 2.6 K.Comment: 4 pages, 6 figure
PMN transendothelial migration decreases nuclear NFκB in IL-1β–activated endothelial cells: role of PECAM-1
During the systemic inflammatory response, circulating cytokines interact with the vascular endothelium, resulting in activation and nuclear accumulation of the nuclear transcription factor, nuclear factor kappa B (NFκB). In turn, NFκB transactivates relevant proinflammatory genes, resulting in an amplification of the inflammatory response. Because this scenario is potentially detrimental to the host, mechanisms exist to limit this amplification. Using an in vitro system that mimics the vascular–interstitial interface during inflammation (cell culture inserts), we provide evidence for the existence of a novel negative feedback mechanism on NFκB activity. We show that the interleukin 1β–induced accumulation of nuclear NFκB in human umbilical vein endothelial cell monolayers is dramatically reduced when polymorphonuclear leukocytes (PMN) are allowed to migrate across these monolayers. This effect does not appear to be due to PMN-derived elastase or nitric oxide. Fixed PMN (adhere but do not migrate) did not affect nuclear NFκB. Furthermore, cross-linking of platelet-endothelial cell adhesion molecule-1 (PECAM-1), but not intercellular adhesion molecule-1, reduces human umbilical vein endothelial cell nuclear NFκB induced by interleukin 1β. Finally, interaction of PMN with PECAM-1–deficient endothelial cells does not reduce nuclear NFκB. These observations indicate that engagement of PECAM-1 by emigrating PMN is a pivotal event in this negative feedback on NFκB activity
Superconductivity, critical current density, and flux pinning in MgB_{2-x}(SiC)_{x/2} superconductor after SiC nanoparticle doping
We investigated the effect of SiC nano-particle doping on the crystal lattice
structure, critical temperature T_c, critical current density J_c, and flux
pinning in MgB_2 superconductor. A series of MgB_{2-x}(SiC)_{x/2} samples with
x = 0 to 1.0 were fabricated using in-situ reaction process. The contraction of
the lattice and depression of T_c with increasing SiC doping level remained
rather small due to the counter-balanced effect of Si and C co-doping. The high
level Si and C co-doping allowed the creation of intra-grain defects and highly
dispersed nano-inclusions within the grains which can act as effective pinning
centers for vortices, improving J_c behavior as a function of the applied
magnetic field. The enhanced pinning is mainly attributable to the
substitution-induced defects and a local structure fluctuations within grains.
A pinning mechanism is proposed to account for different contributions of
different defects in MgB_{2-x}(SiC)_{x/2} superconductors.Comment: 7 pages, 8 figure
Learning 3D Human Pose from Structure and Motion
3D human pose estimation from a single image is a challenging problem,
especially for in-the-wild settings due to the lack of 3D annotated data. We
propose two anatomically inspired loss functions and use them with a
weakly-supervised learning framework to jointly learn from large-scale
in-the-wild 2D and indoor/synthetic 3D data. We also present a simple temporal
network that exploits temporal and structural cues present in predicted pose
sequences to temporally harmonize the pose estimations. We carefully analyze
the proposed contributions through loss surface visualizations and sensitivity
analysis to facilitate deeper understanding of their working mechanism. Our
complete pipeline improves the state-of-the-art by 11.8% and 12% on Human3.6M
and MPI-INF-3DHP, respectively, and runs at 30 FPS on a commodity graphics
card.Comment: ECCV 2018. Project page: https://www.cse.iitb.ac.in/~rdabral/3DPose
Generalized KdV Equation for Fluid Dynamics and Quantum Algebras
We generalize the non-linear one-dimensional equation of a fluid layer for
any depth and length as an infinite order differential equation for the steady
waves. This equation can be written as a q-differential one, with its general
solution written as a power series expansion with coefficients satisfying a
nonlinear recurrence relation. In the limit of long and shallow water (shallow
channels) we reobtain the well known Korteweg-de-Vries equation together with
its single-soliton solution.Comment: 17 pages, Latex, PACS: 47.20.Ky, 43.25.Rq, 47.35.+i, 03.40.Kf,
43.25.Fe, 02.20.Tw, MSC: 16W30, 17B37, 81R50, 35Q51, 34B15, 34L30, 76E3
Manufacture of micro-electro-mechanical-system using sacrificial layer made of silicon, useful for micro-electro-mechanical-system device architecture, e.g. radio-frequency capacitive switch and current switch
NOVELTY - A micro-electro-mechanical-system (MEMS) is manufactured by the use of a sacrificial layer that is made of silicon. USE - The invention is used in surface micromachining for the manufacture of a MEMS containing a suspended metal layer or MEMS device architecture. MEMS device is a suspended gate metal oxide semiconductor field effect transistor (SG-MOSFET). It is used as radio-frequency capacitive switch, current switch, radio-frequency tuneable capacitor, magnetic field sensor, accelerometer, and pressure sensor. (all claimed
Non-invasive methods applied for complex signals
This paper presents the application of a novel algorithm on virtually generated data from patients during anesthesia. Realistic artefacts are simulated in order to validate the usefulness of the proposed methods in separating the signal components: biological trend and artefacts. The results show that the proposed new algorithm can be successfully employed on biological signals to dynamically extract information and distil useful parameters for clinical evaluation
Equations of the Camassa-Holm Hierarchy
The squared eigenfunctions of the spectral problem associated with the
Camassa-Holm (CH) equation represent a complete basis of functions, which helps
to describe the inverse scattering transform for the CH hierarchy as a
generalized Fourier transform (GFT). All the fundamental properties of the CH
equation, such as the integrals of motion, the description of the equations of
the whole hierarchy, and their Hamiltonian structures, can be naturally
expressed using the completeness relation and the recursion operator, whose
eigenfunctions are the squared solutions. Using the GFT, we explicitly describe
some members of the CH hierarchy, including integrable deformations for the CH
equation. We also show that solutions of some - dimensional members of
the CH hierarchy can be constructed using results for the inverse scattering
transform for the CH equation. We give an example of the peakon solution of one
such equation.Comment: 10 page
Lines on projective varieties and applications
The first part of this note contains a review of basic properties of the
variety of lines contained in an embedded projective variety and passing
through a general point. In particular we provide a detailed proof that for
varieties defined by quadratic equations the base locus of the projective
second fundamental form at a general point coincides, as a scheme, with the
variety of lines. The second part concerns the problem of extending embedded
projective manifolds, using the geometry of the variety of lines. Some
applications to the case of homogeneous manifolds are included.Comment: 15 pages. One example removed; one remark and some references added;
typos correcte
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