9,562 research outputs found
Code of Practice for Organic Food Processing. With contributions from Ursula Kretzschmar, Angelika Ploeger and Otto Schmid.
The consumers of âlow inputâ and organic foods have specific expectations with respect to quality parameters of processed food. These may relate to the degree of processing, concern about specific additives, nutritional composition, integrity or whole food concepts, the degree of convenience, the level of energy use and transportation distances, but also to food safety.
For many processors, fulfilling all of these expectations represents a tremendous challenge in understanding and implementing the standards requirements in daily practise. Therefore, it is necessary to have in this field a guidance document for processors as well as standard setting institutions and certification/inspection bodies.
In the EU project on âQuality of low input foodâ (QLIF, No. 50635), which deals with food safety and quality issues related to food from low-input and organic food systems, it was possible to elaborate a specific code of practise for food processing as part of the Subproject 5 on processing.
The starting point for this publication was a literature survey about underlying principles of organic and low-input food processing (Schmid, Beck, Kretzschmar, 2004) and a broad European-wide consultation in 2 rounds, which was also undertaken in the QLIF-project. The results of these studies showed that many companies have serious questions related to the implementation practice of the complex requirements for organic food. Some recent scandals in this sector have made clear that in several areas an improvement of the current practises are necessary, e.g. the separation practises between organic and conventional foods.
The aim of this âCode of good practice for organic food processingâ (COPOF) is to give companies a comprehensive introduction to the most important requirements of the organic food sector applicable for the daily practice. Additionally, the COPOF offers a number of tools that make it possible to:
a) improve the production skills effectively,
b) improve and maintain the quality of organic foods and
c) guarantee the safety of organic products.
The basic idea of this publication was that the responsible persons in companies producing and handling the products have a strongest influence on the final products characteristics themselves. Therefore, their knowledge, abilities and the structural conditions for their work are most important factors to ensure a high quality and safety of the produced food
Concept papers outlining parameters for further development of Organic Food Processing - Crucial topics for the revision of the EU regulation 2092/91
Four concept papers outline parameters for the further development of organic food processing. They are based on other work already executed in the subproject 5 Processing in the QLIF-project, in particular the literature survey on âUnderlying Principles in Organic and "Low-Input Foodâ Processing â Literature Surveyâ published in 2004 by Schmid, Beck and Kretzschmar, as well as the âApproaches used in Organic/Low Input Food Processing - impact on food quality and safetyâ results of a Delphi survey from an expert consultation in 13 European countries.â (Kretzschmar, Schmid, 2006).
The four crucial topics highlighted in concept papers that have been chosen are summarised below:
- 1rd Concept paper on the chances for a concept of âquality of originâ and on criteria and procedures for the evaluation of additives for organic food processing
-2nd concept paper on environmental orientation of organic foods producing processing companies
-3rd concept paper on processing methods and their labelling
-4th concept paper on the improvement of separation practice by parallel processing of conventional and organic product
Time Series Analysis and Market Microstructure Aspects on Short Time Scales
ARMA-GARCH and FIGARCH models with non-normal, tempered-stable innovations are applied to intraday financial time-series on high-frequency time scales. The goal is to investigate their risk forecasting performance and to observe random scaling behavior. To this end, Value-at-Risk (VaR) and Conditional VaR is predicted. In the second part limit order books based on real trading information are modeled with a statistical-learning approach in order to forecast the execution of passive limit orders
Synthetic X-ray and radio maps for two different models of Stephan's Quintet
We present simulations of the compact galaxy group Stephan's Quintet (SQ)
including magnetic fields, performed with the N-body/smoothed particle
hydrodynamics (SPH) code \textsc{Gadget}. The simulations include radiative
cooling, star formation and supernova feedback. Magnetohydrodynamics (MHD) is
implemented using the standard smoothed particle magnetohydrodynamics (SPMHD)
method. We adapt two different initial models for SQ based on Renaud et al. and
Hwang et al., both including four galaxies (NGC 7319, NGC 7320c, NGC 7318a and
NGC 7318b). Additionally, the galaxies are embedded in a magnetized, low
density intergalactic medium (IGM). The ambient IGM has an initial magnetic
field of G and the four progenitor discs have initial magnetic fields
of G. We investigate the morphology, regions of star
formation, temperature, X-ray emission, magnetic field structure and radio
emission within the two different SQ models. In general, the enhancement and
propagation of the studied gaseous properties (temperature, X-ray emission,
magnetic field strength and synchrotron intensity) is more efficient for the SQ
model based on Renaud et al., whose galaxies are more massive, whereas the less
massive SQ model based on Hwang et al. shows generally similar effects but with
smaller efficiency. We show that the large shock found in observations of SQ is
most likely the result of a collision of the galaxy NGC 7318b with the IGM.
This large group-wide shock is clearly visible in the X-ray emission and
synchrotron intensity within the simulations of both SQ models. The order of
magnitude of the observed synchrotron emission within the shock front is
slightly better reproduced by the SQ model based on Renaud et al., whereas the
distribution and structure of the synchrotron emission is better reproduced by
the SQ model based on Hwang et al..Comment: 20 pages, 15 figures, accepted to MNRA
Strong magnetic fields and large rotation measures in protogalaxies by supernova seeding
We present a model for the seeding and evolution of magnetic fields in
protogalaxies. Supernova (SN) explosions during the assembly of a protogalaxy
provide magnetic seed fields, which are subsequently amplified by compression,
shear flows and random motions. We implement the model into the MHD version of
the cosmological N-body / SPH simulation code GADGET and we couple the magnetic
seeding directly to the underlying multi-phase description of star formation.
We perform simulations of Milky Way-like galactic halo formation using a
standard LCDM cosmology and analyse the strength and distribution of the
subsequent evolving magnetic field. A dipole-shape divergence-free magnetic
field is injected at a rate of 10^{-9}G / Gyr within starforming regions, given
typical dimensions and magnetic field strengths in canonical SN remnants.
Subsequently, the magnetic field strength increases exponentially on timescales
of a few ten million years. At redshift z=0, the entire galactic halo is
magnetized and the field amplitude is of the order of a few G in the
center of the halo, and 10^{-9} G at the virial radius. Additionally, we
analyse the intrinsic rotation measure (RM) of the forming galactic halo over
redshift. The mean halo intrinsic RM peaks between redshifts z=4 and z=2 and
reaches absolute values around 1000 rad m^{-2}. While the halo virializes
towards redshift z=0, the intrinsic RM values decline to a mean value below 10
rad m^{-2}. At high redshifts, the distribution of individual starforming, and
thus magnetized regions is widespread. In our model for the evolution of
galactic magnetic fields, the seed magnetic field amplitude and distribution is
no longer a free parameter, but determined self-consistently by the star
formation process occuring during the formation of cosmic structures.Comment: 13 pages, 14 figures, accepted to MNRAS after moderate revisio
Quantifying correlations between galaxy emission lines and stellar continua
We analyse the correlations between continuum properties and emission line
equivalent widths of star-forming and active galaxies from the Sloan Digital
Sky Survey. Since upcoming large sky surveys will make broad-band observations
only, including strong emission lines into theoretical modelling of spectra
will be essential to estimate physical properties of photometric galaxies. We
show that emission line equivalent widths can be fairly well reconstructed from
the stellar continuum using local multiple linear regression in the continuum
principal component analysis (PCA) space. Line reconstruction is good for
star-forming galaxies and reasonable for galaxies with active nuclei. We
propose a practical method to combine stellar population synthesis models with
empirical modelling of emission lines. The technique will help generate more
accurate model spectra and mock catalogues of galaxies to fit observations of
the new surveys. More accurate modelling of emission lines is also expected to
improve template-based photometric redshift estimation methods. We also show
that, by combining PCA coefficients from the pure continuum and the emission
lines, automatic distinction between hosts of weak active galactic nuclei
(AGNs) and quiescent star-forming galaxies can be made. The classification
method is based on a training set consisting of high-confidence starburst
galaxies and AGNs, and allows for the similar separation of active and
star-forming galaxies as the empirical curve found by Kauffmann et al. We
demonstrate the use of three important machine learning algorithms in the
paper: k-nearest neighbour finding, k-means clustering and support vector
machines.Comment: 14 pages, 14 figures. Accepted by MNRAS on 2015 December 22. The
paper's website with data and code is at
http://www.vo.elte.hu/papers/2015/emissionlines
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