492 research outputs found
Magnetic resonance imaging (MRI) of heavy-metal transport and fate in an artificial biofilm
Unlike planktonic systems, reaction rates in biofilms are often limited by mass transport, which controls the rate of supply of contaminants into the biofilm matrix. To help understand this phenomenon, we investigated the potential of magnetic resonance imaging (MRI) to spatially quantify copper transport and fate in biofilms. For this initial study we utilized an artificial biofilm composed of a 50:50 mix of bacteria and agar. MRI successfully mapped Cu2+ uptake into the artificial biofilm by mapping T2 relaxation rates. A calibration protocol was used to convert T2 values into actual copper concentrations. Immobilization rates in the artificial biofilm were slow compared to the rapid equilibration of planktonic systems. Even after 36 h, the copper front had migrated only 3 mm into the artificial biofilm and at this distance from the copper source, concentrations were very low. This slow equilibration is a result of (1) the time it takes copper to diffuse over such distances and (2) the adsorption of copper onto cell surfaces, which further impedes copper diffusion. The success of this trial run indicates MRI could be used to quantitatively map heavy metal transport and immobilization in natural biofilms
Capturing the sporting heroes of our past by extracting 3D movements from legacy video content
Sports are a key part of cultural identity, and it is necessary to preserve them as important intangible Cultural Heritage, especially the human motion techniques specific to individual sports. In this paper we present a method for extracting 3D athlete motion from video broadcast sources, providing an important tool for preserving the heritage represented by these movements. Broadcast videos include camera motion, multiple player interaction, occlusions and noise, presenting significant challenges to solve the reconstruction. The approach requires initial definition of some key-frames and setting of 2D key-points in those frames manually. Thereafter an automatic process estimates the poses and positions of the players in the key-frames, and in the frames between key-frames, taking into account collisions with the environment and human kinematic constraints. Initial results are extremely promising and this data could be used to analyze the sport's evolution over time, or even to generate animations for interactive applications
Frobenius Splittings
We give a gentle introduction to Frobenius splittings. Then we recall a few
results that have been obtained with the method.Comment: 21 pages, typos correcte
Steinberg modules and Donkin pairs
We prove that in positive characteristic a module with good filtration for a
group of type E6 restricts to a module with good filtration for a subgroup of
type F4. (Recall that a filtration of a module for a semisimple algebraic group
is called good if its layers are dual Weyl modules.) Our result confirms a
conjecture of Brundan for one more case. The method relies on the canonical
Frobenius splittings of Mathieu. Next we settle the remaining cases, in
characteristic not 2, with a computer-aided variation on the old method of
Donkin.Comment: 16 pages; proof of Brundan's conjecture adde
Stringent constraints on the scalar K pi form factor from analyticity, unitarity and low-energy theorems
We investigate the scalar K pi form factor at low energies by the method of
unitarity bounds adapted so as to include information on the phase and modulus
along the elastic region of the unitarity cut. Using at input the values of the
form factor at t=0 and the Callan-Treiman point, we obtain stringent
constraints on the slope and curvature parameters of the Taylor expansion at
the origin. Also, we predict a quite narrow range for the higher order ChPT
corrections at the second Callan-Treiman point.Comment: 5 pages latex, uses EPJ style files, 3 figures, replaced with version
accepted by EPJ
Remarks on lines and minimal rational curves
We determine all of lines in the moduli space of stable bundles for
arbitrary rank and degree. A further application of minimal rational curves is
also given in last section
Production of bioplastic using Jackfruit perianth
Overuse of plastics around the world has made them one of the key environmental concerns today. Disposal of plastic waste in landfills has serious environmental impacts due to its non-biodegradable nature. Agricultural waste, particularly plant materials containing starch gains attraction for its role in the production of alternative biodegradable materials with good tensile strength and other mechanical properties. The present work focuses on production of biodegradable bioplastic using perianth of Jackfruit [Artocarpus heterophyllus Lam. (Moraceae)], which otherwise goes as agro waste. Certain plasticizers are also used to improve the raw materials properties and it was subjected to various tests, to study its mechanical and chemical properties. The sample was characterized using Fourier transform Infrared spectroscopy (FTIR) and tensile strength was also checked. It was subjected to various resistance tests such as water resistance, alcohol resistance, flammability, alkali and acid resistance and it was confirmed that the bioplastic produced from Jack fruit perianth is a good option to normal plastics
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