Organic Farming in Austria

During the present decade, Austria has experienced a dramatic increase in organic farming among those countries that comprise the European Union (EU). For example, in 1992, approximately 2,000 farms were practicing organic, ecological, or biodynamic farming methodes. By 1997 the number of certified organic farms plus those in transition from conventional farming had increased 10-fold to some 20,000 farms. This represents almost 9% of the total farms in Austria and an area of 345,375 ha, or 10% of the total cultivated farmland. The largest concentration of organic farms is in regions with a high proportion of alpine grassland or pastures. Approximately 50% of the organic farms range in size from 5 to 15 ha. The strong organic movement in Austria can be attributed to a) government subsidies which provide incentives to organic farmers and b) widepread acceptance of organic products and their brand names by large food chains and supermarkets. More than 60% of organic farmers are affiliated with associations and organizations that provide advisory and support services in marketing activities. Certification of organic farms and food processors is conducted by seven monitoring bodies according to EU regulations No. 2092/91, which guarantees legally-binding standards of food saftey and quality to EU consumers, and according to the Austian Alimentari Codex. Since January 1998, all monitoring/certifying bodies in Austria must verify accreditation according to rgulation European Norm 45011. The major supermarket chain offers a variety of organic dairy and meat products, as well as organic ice cream, pizza, vegetables, fruits, baby foods, and bread. The current domestic wholesale value of organic products arketed from Austria farms is approximately 170 million US$ annually. Unfortunately, funding for support of scientific research and extension to enhance organic farming and marketing has not kept pace with the increasing number of organic farms and farmers. Additional funding is essential to ensure the sustainable development of the organic movement and the organic market

Hemp (Cannabis sativa L.) as a Resource for Green Cosmetics: Yield of Seeds and Fatty Acids Composition of 20 Varieties under the Growing Conditions of Organic Farming in Austria

The interest in hemp (non-drug Cannabis sativa L.) for skin care and cosmetic use is due to the high content of oil, especially unsaturated fatty acids in seed with technological and therapeutic effects. In a field trial on an organic farm, seed weight and content of fatty acids of 20 hemp varieties were surveyed on three different harvest dates. The dry matter seed yields ranged from 27-149 g m2. The varieties Ferimon-12, Fedora-19, and Bialobreszie produced high seed yields on all three harvest dates but yields were not significantly different from a large group of other varieties. Contents of palmitic acid range from 3.1 to 4.1%, of stearic acid from 0.1 to 1.9%, of oleic acid from 3.7 to 9.2%, of linoleic acid from 44.8 to 60.2%, of α-linolenic acid from 18.2 to 27.4%, and of γ-linolenic acid from 1.6 to 4.7%. The genotype has no significant influence on fatty acid content. All 20 varieties tested show high quantities of fatty acid depending on the harvest date, so that no variety can be favored. Results confirm that hemp is a very good source of fatty acids for skin care and cosmetic use

Density Effect on Hadronization of a Quark Plasma

The hadronization cross section in a quark plasma at finite temperature and density is calculated in the framework of Nambu--Jona-lasinio model with explicit chiral symmetry breaking. In apposition to the familiar temperature effect, the quark plasma at high density begins to hadronize suddenly. It leads to a sudden and strong increase of final state pions in relativistic heavy ion collisions which may be considered as a clear signature of chiral symmetry restoration.Comment: Latex2e, 11 pages, 7 Postscript figures, submitted to Phys. Rev.

Gate control of low-temperature spin dynamics in two-dimensional hole systems

We have investigated spin and carrier dynamics of resident holes in high-mobility two-dimensional hole systems in GaAs/Al$_{0.3}$Ga$_{0.7}$As single quantum wells at temperatures down to 400 mK. Time-resolved Faraday and Kerr rotation, as well as time-resolved photoluminescence spectroscopy are utilized in our study. We observe long-lived hole spin dynamics that are strongly temperature dependent, indicating that in-plane localization is crucial for hole spin coherence. By applying a gate voltage, we are able to tune the observed hole g factor by more than 50 percent. Calculations of the hole g tensor as a function of the applied bias show excellent agreement with our experimental findings.Comment: 8 pages, 7 figure

Realistic Tight Binding Model for the Electronic Structure of II-VI Semiconductors

We analyze the electronic structure of group II-VI semiconductors obtained within LMTO approach in order to arrive at a realistic and minimal tight binding model, parameterized to provide an accurate description of both valence and conduction bands. It is shown that a nearest-neighbor $sp^3d^5$ model is fairly sufficient to describe to a large extent the electronic structure of these systems over a wide energy range, obviating the use of any fictitious $s^*$ orbital. The obtained hopping parameters obey the universal scaling law proposed by Harrison, ensuring transferability to other systems. Furthermore, we show that certain subtle features in the bonding of these compounds require the inclusion of anion-anion interactions in addition to the nearest-neighbor cation-anion interactions.Comment: 9 pages, 9 figure

The phase diagram and bulk thermodynamical quantities in the NJL model at finite temperature and density

We reexamine the recent instanton motivated studies of Alford, Rajagopal and Wilczek, and Berges and Rajagopal in the framework of the standard SU(2) Nambu-Jona-Lasinio model. The chiral phase diagram is calculated in the temperature--density plane, and the pressure is evaluated as the function of the density. Obtaining simple approximate relations describing the $T$-$\mu$ and $T$-$p_F$ phase transition lines we find that the results of the instanton based model and that of the NJL model are identical. The diquark transition line is also given.Comment: 11 pages LaTeX plus 7 PS figures. One figure has been added and there are some changes in the text describing thi

Quark and Nucleon Self-Energy in Dense Matter

In a recent work we introduced a nonlocal version of the Nambu--Jona-Lasinio(NJL) model that was designed to generate a quark self-energy in Euclidean space that was similar to that obtained in lattice simulations of QCD. In the present work we carry out related calculations in Minkowski space, so that we can study the effects of the significant vector and axial-vector interactions that appear in extended NJL models and which play an important role in the study of the $\rho$, $\omega$ and $a_1$ mesons. We study the modification of the quark self-energy in the presence of matter and find that our model reproduces the behavior of the quark condensate predicted by the model-independent relation $_{\rho} = <\bar qq>_0(1-\sigma_N\rho_N/f_{\pi}^2m_{\pi}^2 +...)$, where $\sigma_N$ is the pion-nucleon sigma term and $\rho_N$ is the density of nuclear matter. (Since we do not include a model of confinement, our study is restricted to the analysis of quark matter. We provide some discussion of the modification of the above formula for quark matter.) The inclusion of a quark current mass leads to a second-order phase transition for the restoration of chiral symmetry. That restoration is about 80% at twice nuclear matter density for the model considered in this work. We also find that the part of the quark self-energy that is explicitly dependent upon density has a strong negative Lorentz-scalar term and a strong positive Lorentz-vector term, which is analogous to the self-energy found for the nucleon in nuclear matter when one makes use of the Dirac equation for the nucleon. In this work we calculate the nucleon self -energy in nuclear matter using our model of the quark self-energy and obtain satisfactory results.Comment: 19 pages, 8 figures, 2 tables, revte