2,873 research outputs found
Organic milk supply in Poland: market and policy developments
Purpose
Global demand for organic milk products gives an opportunity to Polish organic farmers and dairies to supply national, European Union and international milk markets. The aim of this study is to review the historic and contemporary changes in organic milk production and processing in Poland, in order to identify the main factors of influence and to propose the direction of future market and policy development in the sector.
Design/methodology/approach
In this study, secondary data from a range of literature sources and databases is analysed. The Lorenz’s concentration ratio is applied to the data derived to evaluate the degree of concentration of certified organic farms in the different regions of Poland and conclusions are drawn as a result.
Findings
Organic dairy farm operations in Poland are small scale and territorially dispersed. Although there is some evidence of growing supply concentration, Polish processors of organic milk face multiple barriers to development not least a lack of continuity of supplies. Whilst global markets are of interest, the development of alternative, innovative food networks in Poland that focus on provenance, integrity and promoting the special health benefits of organic milk would be of value to the sector, but further co-operation and integration is essential to take advantage of these market opportunities.
Originality
This research underpins the need for appropriate national policies in Poland for the development and actualisation of a dynamic organic milk supply system that delivers value to local, regional and international markets
Scaling of human behavior during portal browsing
We investigate transitions of portals users between different subpages. A
weighted network of portals subpages is reconstructed where edge weights are
numbers of corresponding transitions. Distributions of link weights and node
strengths follow power laws over several decades. Node strength increases
faster than linearly with node degree. The distribution of time spent by the
user at one subpage decays as power law with exponent around 1.3. Distribution
of numbers P(z) of unique subpages during one visit is exponential. We find a
square root dependence between the average z and the total number of
transitions n during a single visit. Individual path of portal user resembles
of self-attracting walk on the weighted network. Analytical model is developed
to recover in part the collected data.Comment: 6 pages, 7 figure
Oznaczanie poziomów zawartości surfaktantów w próbkach środowiskowych. Część 3. Niejonowe związki
Non-ionic surface active agents are a diverse group of chemicals which have an uncharged polar head
and a non-polar tail. They have different properties due to amphiphilic structure of their molecules. Commercial
available non-ionic surfactants consist of the broadest spectrum of compounds in comparison with other types of
such agents. Typically, non-ionic compounds found applications in households and industry during formulation
of cleaning products, cosmetics, paints, preservative coatings, resins, textiles, pulp and paper, petroleum products
or pesticides. Their are one of the most common use class of surfactants which can be potential pollution sources
of the different compartment of environment (because of they widely application or discharging treated
wastewaters to surface water and sludge in agricultural). It is important to investigate the behavior, environmental
fate of non-ionic surfactants and their impact on living organisms (they are toxic and/or can disrupt endocrine
functions). To solve such problems should be applied appropriated analytical tools. Sample preparation step is one
of the most critical part of analytical procedures in determination of different compounds in environmental
matrices. Traditional extraction techniques (LLE - for liquid samples; SLE - for solid samples) are time and
solvent-consuming. Developments in this field result in improving isolation efficiency and decreasing solvent
consumption (eg SPE and SPME - liquid samples or PLE, SFE and MAE - solid samples). At final determination
step can be applied spectrophotometric technique, potentiometric titrametration or tensammetry (determination
total concentration of non-ionic surfactants) or chromatographic techniques coupled with appropriated detection
techniques (individual analytes). The literature data concerning the concentrations of non-ionic surfactants in the
different compartments of the environment can give general view that various ecosystems are polluted by those
compounds
X-ray Emitting GHz-Peaked Spectrum Galaxies: Testing a Dynamical-Radiative Model with Broad-Band Spectra
In a dynamical-radiative model we recently developed to describe the physics
of compact, GHz-Peaked-Spectrum (GPS) sources, the relativistic jets propagate
across the inner, kpc-sized region of the host galaxy, while the electron
population of the expanding lobes evolves and emits synchrotron and
inverse-Compton (IC) radiation. Interstellar-medium gas clouds engulfed by the
expanding lobes, and photoionized by the active nucleus, are responsible for
the radio spectral turnover through free-free absorption (FFA) of the
synchrotron photons. The model provides a description of the evolution of the
spectral energy distribution (SED) of GPS sources with their expansion,
predicting significant and complex high-energy emission, from the X-ray to the
gamma-ray frequency domain. Here, we test this model with the broad-band SEDs
of a sample of eleven X-ray emitting GPS galaxies with Compact-Symmetric-Object
(CSO) morphology, and show that: (i) the shape of the radio continuum at
frequencies lower than the spectral turnover is indeed well accounted for by
the FFA mechanism; (ii) the observed X-ray spectra can be interpreted as
non-thermal radiation produced via IC scattering of the local radiation fields
off the lobe particles, providing a viable alternative to the thermal,
accretion-disk dominated scenario. We also show that the relation between the
hydrogen column densities derived from the X-ray (N_H) and radio (N_HI) data of
the sources is suggestive of a positive correlation, which, if confirmed by
future observations, would provide further support to our scenario of
high-energy emitting lobes.Comment: 29 pages, 3 figures, 6 tables; to appear in ApJ. A few clarifications
included, according to referee's suggestion
Radiation pressure acting on the neutral He atoms in the Heliosphere
The Interstellar Neutral Helium (ISN He) is an important source of
information on the physical state of the Local Interstellar Medium. Radiation
pressure acting on the neutral helium atoms in the heliosphere has always been
neglected, its effect has been considered insignificant compared to
gravitational force. The most advanced numerical models of ISN He take into
account more and more subtle effects, therefore it is important to check if the
effect of radiation pressure is still negligible. In this paper, we use the
most up-to-date version of the Warsaw Test Particle Model (WTPM) to calculate
the expected helium distribution in the heliosphere, and simulate the flux of
ISN He observed by the Interstellar Boundary Explorer (IBEX) and in the future
by the Interstellar Mapping and Acceleration Probe (IMAP). We compare results
calculated with and without radiation pressure during low and high solar
activity. The results show that in the analysis of IBEX-Lo observations the
radiation pressure acting on typical helium causes flux differences at a level
of 1-4% and is comparable to the observational errors. For the more sensitive
IMAP-Lo instrument, there are some regions in the considered observations
configurations where radiation pressure causes potentially statistically
significant changes in the calculated fluxes. The effect can be up to 9% for
the indirect beam and is likely to be higher than the estimated errors.
Therefore, we claim that in the future analysis of the IMAP-Lo observations
radiation pressure acting on ISN He should be considered.Comment: Accepted to Ap
Uticaj -hidroksi--metilbutirata (hmb) dodavanog u hranu na imunitet i otpornost na bakterijske infekcije kod smuđa (sander lucioperca)
U ovoj studiji je ispitivan uticaj metabolita leucina β-hidroksi-β-metilbutirata (HMB) na imunitet i zaštitu od enterične bolesti crvenih usta (ERM) i furunkuloze kod smuđa (Sander lucioperca). Ribe su bile hranjene 18 sati dnevno komercijalnom hranom za pastrmke. Hrana je formulisana tako da obezbedi ili 0 (kontrolna grupa) ili 50 mg HBM/kg telesne težine na dan (grupa hranjena sa HBM) tokom 4 nedelje. Posle hranjenja sa HBM 20 zdravih smuđeva prosečne težine 35 g je anestezirano i uzeta je krv iz kaudalne vene u heparizovane špriceve. Takođe je aseptično izdvojen pronefros svake ribe i dobijena suspenzija pojedinačnih ćelija za izolovanje ćelija koristeći ili Gradisol (Polfa) ili Percoll (Pharmacia) gradijent. Test na izazivanje bolesti upotrebom Yersinia ruckeri ili Aeromonas salmonicida je obavljen 4 nedelje posle hranjenja. Ukratko, svakoj od 20 riba svake grupe data je jedna intraperitonealna injekcija 48 sati kulture Y.ruckeri ili A. salmonicida (0,2 ml). Zabeležen je mortalitet, a prisustvo patogena potvrđeno izolacijom iz bubrega. Rezultati ovog ogleda pokazuju da HBM u dozi od 50 mg/kg telesne težine statistički značajno stimuliše nespecifične ćelijske i humoralne odbrambene mehanizme i zaštitu od Yersinia ruckeri i Aeromonas salmonicida
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