A study of the influence of the gauge group on the Dyson-Schwinger equations for scalar-Yang-Mills systems

The particular choice of the gauge group for Yang-Mills theory plays an important role when it comes to the influence of matter fields. In particular, both the chosen gauge group and the representation of the matter fields yield structural differences in the quenched case. Especially, the qualitative behavior of the Wilson potential is strongly dependent on this selection. Though the algebraic reasons for this observation is clear, it is far from obvious how this behavior can be described besides using numerical simulations. Herein, it is investigated how the group structure appears in the Dyson-Schwinger equations, which as a hierarchy of equations for the correlation functions have to be satisfied. It is found that there are differences depending on both the gauge group and the representation of the matter fields. This provides insight into possible truncation schemes for practical calculations using these equations.Comment: 47 page

Reducing russeting of organically grown Elstar to increase quality

Sales organisations indicated that opportunities for organic apples sales can increase when quality increases, in particular reducing the amount of russeting. The use of copper is probably the most important factor for russeting. Therefore a worst case scheme was compared with a scheme with reduced copper application. Furthermore, there was a particular interest in the effects on russeting of potassium bicarbonate (Armicarb) because this product might be an important element in a copper free fungicide scheme. Application of Armicarb was investigated on wet or dry canopy and effects of two different dosages were studied. All the schemes were compared with a worst case organic fungicide scheme with copper. The experiment was done on two year old Elstar trees because Elstar is the most important organically grown cultivar in the Netherlands. Effects of the schedules on russet and scab control were evaluated. At harvest no effects were found on scab. Between the different schemes with copper no differences were found in amount of russet. Only the highest dosage of Armicarb (10 kg/ha) and the schedules with Armicarb on a wet canopy gave more russet compared with the worst case scheme. Also effects on fruit rot were evaluated

Explaining German imports of olive oil: evidence from a gravity model

In this study the case of olive oil imports of Germany is examined since olive oil is a traditional Mediterranean commodity and Germany is the biggest importer in the EU. A gravity model has been employed so as to analyse those factors that explain the German imports of olive oil that were identified in a preceding analysis of the German olive oil supply chain. The results of two random-effects models corrected for serial correlation and heteroskedasticity suggest that being a Mediterranean Partner country of the EU has the highest impact on trade flows to Germany, thus supporting further Euromediterranean trade integration. The level of trade to Germany is positively related to existence of direct marketing channels and to tourism implying that these factors should be explored more in the future by the Mediterranean countries so as to boost their exports.gravity model, olive oil, Germany, International Relations/Trade,

Evolution of olive oil import demand structures in nonproducing countries: the cases of Germany and the UK

Consumption patterns of olive oil have changed over recent years influencing the supply chain. The consumption has increased in countries where olive oil is not part of the traditional diet as for example Germany and the UK, where the average consumption grew by 11 and 13% respectively during the period 1995-2003. The opening of new non-traditional markets has shifted exports and re-structured the supply chain. Mediterranean countries have been the traditional suppliers of olive oil with the EU Mediterranean Member States being the main exporters and with the non-EU Mediterranean countries trying to gain market shares in the EU markets in an attempt to benefit from the preferential access due to the Barcelona Agreement. This paper tries to identify which factors influenced olive oil demand of non-traditional consumers using Germany and the UK as case studies with the help of a gravity model. The results of the random effects models corrected for serial correlation and heteroskedasticity indicate that the Barcelona Agreement has boosted the non-EU Mediterranean exports to Germany and the UK while olive oil exports are positively related to direct marketing strategies and tourism, implying that these factors have the largest impact on the olive oil exports from producing countries and consequently on the overall supply chain.Olive oil, gravity model, import demand, Germany, UK, Agricultural and Food Policy, Food Consumption/Nutrition/Food Safety,

A luminosity monitor for the A4 parity violation experiment at MAMI

A water Cherenkov luminosity monitor system with associated electronics has been developed for the A4 parity violation experiment at MAMI. The detector system measures the luminosity of the hydrogen target hit by the MAMI electron beam and monitors the stability of the liquid hydrogen target. Both is required for the precise study of the count rate asymmetries in the scattering of longitudinally polarized electrons on unpolarized protons. Any helicity correlated fluctuation of the target density leads to false asymmetries. The performance of the luminosity monitor, investigated in about 2000 hours with electron beam, and the results of its application in the A4 experiment are presented.Comment: 22 pages, 12 figures, submitted to NIM

Metastable states of surface plasmon vacuum near the interface between metal and nonlinear dielectric

Zero-point fluctuations of surface plasmon modes near the interface between metal and nonlinear dielectric are shown to produce a thin layer of altered dielectric constant near the interface. This effect may be sufficiently large to produce multiple metastable states of the surface plasmon vacuum.Comment: 4 pages, 2 figure

Inertial waves and modes excited by the libration of a rotating cube

We report experimental measurements of the flow in a cubic container submitted to a longitudinal libration, i.e. a rotation modulated in time. Velocity fields in a vertical and a horizontal plane are measured in the librating frame using a corotating particle image velocimetry system. When the libration frequency $\sigma_0$ is smaller than twice the mean rotation rate $\Omega_0$, inertial waves can propagate in the interior of the fluid. At arbitrary excitation frequencies $\sigma_0<2\Omega_0$, the oscillating flow shows two contributions: (i) a basic flow induced by the libration motion, and (ii) inertial wave beams propagating obliquely upward and downward from the horizontal edges of the cube. In addition to these two contributions, inertial modes may also be excited at some specific resonant frequencies. We characterize in particular the resonance of the mode of lowest order compatible with the symmetries of the forcing, noted [2,1,+]. By comparing the measured flow fields to the expected inviscid inertial modes computed numerically [L.R.M. Maas, Fluid Dyn. Res. \textbf{33}, 373 (2003)], we show that only a subset of inertial modes, matching the symmetries of the forcing, can be excited by the libration.Comment: Phys. Fluids (in press

Analysing agricultural productivity growth in a framework of institutional quality

This paper addresses the question whether the institutional environment of transition countries in Eastern Europe affects productivity growth in the agricultural sector. Situated in a neoclassical growth framework, a dynamic panel model for the period 1996-2005 provides evidence that poor institutional quality leads to a slowdown in agricultural productivity growth. Productivity growth is limited by a high degree of corruption, which is of particular importance given that corruption has been proven to be most prevalent in Eastern European countries. Moreover, agricultural productivity in countries where privatisation and transferability of land is restricted is found to grow at a slower rate than countries supporting market-oriented land reforms. Interestingly, the results suggest that a high degree of openness leads to a loss in agricultural productivity, suggesting that timing and sequencing of trade reforms matter. An improvement of the poor institutional quality is thus of central importance to accelerate productivity growth in Eastern European countries. --Eastern Europe,Transition,Productivity growth

Testosterone: Bad for Men, Good for Women?

# The Author(s) 2010. This article is published with open access at Springerlink.com Generally, high testosterone levels within the physiological range are associated with a more favourable cardiometabolic profile. Although the FDA has approved testosterone for use only in men with hypogonadism, whose sex glands produce extremely low amounts of testosterone, off-label use has dramatically increased in recent years. In the past two decades, there has been a huge increase in testosterone prescriptions, and many trials have shown benefit in terms of risk factor modification and symptoms. These observations fit also into the picture that reduced testosterone levels in men are associated with increased cardiovascular risk inducing elevated triglyceride levels, low high-density lipoprotein (HDL) cholesterol levels, central obesity, glucose intolerance, and diabetes. This has recently been demonstrated by Malkin et al. (October 26 issue, 2010, Heart), who showed that low testosterone levels (total testosterone &lt;8.1 nmol/l) are associated with early death in men with heart disease. The longitudinal follow-up study involved 930 men with coronary heart disease for a period of about 7 years. During the study period, 41 of 194 (21%) men with low testosterone levels died compared with 88 of 736 (12%) men with normal levels of the hormone (p=0.002). It was concluded that, if androgen deficiency is part of the underlying pathophysiology of atherosclerotic disease in men, the serum testosterone level could be viewed as a favourable modifiable risk factor. However, this view has been challenged by Basaria et al