The effect of electric field on important food-processing enzymes : comparison of inactivation kinetics under conventional and ohmic heating

This work deals with the determination of the inactivation kinetics of several enzymes, most of them used as time-temperature integrators in the food industry. The tested enzymes were polyphenoloxidase, lipoxygenase, pectinase, alkaline phosphatase, and β-galactosidase, and the inactivation assays were performed under conventional and ohmic heating conditions. The thermal history of the samples (conventional and ohmically processed) was made equal to determine if there was an additional inactivation caused by the presence of an electric field, thus eliminating temperature as a variable. All the enzymes followed 1st-order inactivation kinetics for both conventional and ohmic heating treatments. The presence of an electric field does not cause an enhanced inactivation to alkaline phosphatase, pectinase, and β-galactosidase. However, lipoxygenase and polyphenoloxidase kinetics were significantly affected by the electric field, reducing the time needed for inactivation. The results of the present work can be used industrially to determine processing effectiveness when ohmic heating technology is applied

Manejo de várzeas.

Falta p.39

Equivalence of Fokker-Planck approach and non-linear σ\sigma-model for disordered wires in the unitary symmetry class

The exact solution of the Dorokhov-Mello-Pereyra-Kumar-equation for quasi one-dimensional disordered conductors in the unitary symmetry class is employed to calculate all $m$-point correlation functions by a generalization of the method of orthogonal polynomials. We obtain closed expressions for the first two conductance moments which are valid for the whole range of length scales from the metallic regime ($L\ll Nl$) to the insulating regime ($L\gg Nl$) and for arbitrary channel number. In the limit $N\to\infty$ (with $L/(Nl)=const.$) our expressions agree exactly with those of the non-linear $\sigma$-model derived from microscopic Hamiltonians.Comment: 9 pages, Revtex, one postscript figur

Universal Parametric Correlations of Eigenvalues of Random Matrix Ensemble

Eigenvalue correlations of random matrix ensembles as a function of an external perturbation are investigated vis the Dyson Brownian Motion Model in the situation where the level density has a hard edge singularity. By solving a linearized hydrodynamical equation, a universal dependence of the density-density correlator on the external field is found. As an application we obtain a formula for the variance of linear statistics with the parametric dependence exhibited as a Laplace transform.Comment: 23 pages, late

Path Integral Approach to the Scattering Theory of Quantum Transport

The scattering theory of quantum transport relates transport properties of disordered mesoscopic conductors to their transfer matrix \bbox{T}. We introduce a novel approach to the statistics of transport quantities which expresses the probability distribution of \bbox{T} as a path integral. The path integal is derived for a model of conductors with broken time reversal invariance in arbitrary dimensions. It is applied to the Dorokhov-Mello-Pereyra-Kumar (DMPK) equation which describes quasi-one-dimensional wires. We use the equivalent channel model whose probability distribution for the eigenvalues of \bbox{TT}^{\dagger} is equivalent to the DMPK equation independent of the values of the forward scattering mean free paths. We find that infinitely strong forward scattering corresponds to diffusion on the coset space of the transfer matrix group. It is shown that the saddle point of the path integral corresponds to ballistic conductors with large conductances. We solve the saddle point equation and recover random matrix theory from the saddle point approximation to the path integral.Comment: REVTEX, 9 pages, no figure

The interfruta project and its contribution to the knowledge of chestnut moth (Cydia splendana Hubner)(Lepidoptera: Tortricidae) dispersal and infestation on Terceira Island, Azores

The chestnut moth is one of the principal pests on Terceira Island affecting the quality of all chestnut production. Investigation work developed by the Interfruta II Project (a project of interregional cooperation among the three Atlantic regions: Azores, Madeira and Canaries) aims at increasing interest in fruit and the vineyard production in the three partner regions. The chestnut moth (Cydia splendana Hubner) (Lepidoptera: Tortricidae) is the only specie responsible for chestnut fruit damage. The monitoring of this pest using Delta traps with sex pheromone revealed the adult abundance during the season. The higher activity period was between July and October, the months when the chestnut harvest begins. A map of Terceira Island using a GPS and ArcGis 8.0 software was made showing the locality of all the chestnut production areas studied. In the evaluated orchards, fruit damage reached its maximum of 38% at Terra Chã, 218 m of altitude and a southern exposure, and a minimum of 0% damage at Biscoitos, at about the same altitude but with a northern exposure. In both cases, the percentages of infestation were achieved by analyzing a sample of 2.500 chestnuts for each parcel of land.info:eu-repo/semantics/publishedVersio

Finite element analysis of stress extent at peri-implant bone surrounding external hexagon or Morse taper implants

The purpose of the present study was to evaluate the distribution of stresses and consequent bone volume affected surrounding external hexagon or Morse taper dental implant systems by finite element analysis.The authors acknowledge the support provided by the Dept. of Mechanical Engineering at the University of Minho (Portugal) and by Drawing 3D implicit Finite Element Code (DD3imp, Portugal). This study was supported by FCT-Portugal (EXCL/EMS-TEC/0460/2012; UID/EEA/04436/2013, NORTE-01-0145-FEDER-000018 - HAMaBICo), CNPq-Brazil (PVE/CAPES/CNPq/407035/2013-3).info:eu-repo/semantics/publishedVersio

Kinetic description of particle interaction with a gravitational wave

The interaction of charged particles, moving in a uniform magnetic field, with a plane-polarized gravitational wave is considered using the Fokker-Planck- Kolmogorov (FPK) approach. By using a stochasticity criterion, we determine the exact locations in phase space, where resonance overlapping occurs. We investigate the diffusion of orbits around each primary resonance of order (m) by deriving general analytical expressions for an effective diffusion coeficient. A solution to the corresponding diffusion equation (Fokker-Planck equation) for the static case is found. Numerical integration of the full equations of motion and subsequent calculation of the diffusion coefficient verifies the analytical results.Comment: LaTeX file, 15 page