Strategies to control tree vigour and optimise fruit production in 'Conference' pears

The ban on the use of chlormequat (CCC) in pear orchards in 2001 forced Dutch pear growers to look for alternative methods to control tree vigour and stimulate flower bud development and fruit production. Root pruning and trunk notching have become the major growth retarding methods. In addition to the mechanical methods for controlling tree vigour, Regalis (Prohexadione-Calcium) and ethephon were tested as alternative chemical growth regulators for 'Conference' pears. In 2004, a trial was started in which six different strategies to control tree vigour and optimize fruit production in 'Conference' trees are compared. In 4 strategies root pruning was the major treatment, while in 2 strategies trunk incisions were the initial treatment to reduce tree vigour and stimulate fruit production. In 2005, no further root pruning or trunk incisions were made and ethephon and Regalis were the only treatments applied in some of the strategies. Ethephon and Regalis were also applied in 2006 in addition to root pruning in March and June or in June only. All of the strategies evaluated significantly reduced shoot growth and improved fruit production. Regular yields of 52 to more than 70 tons/ha were achieved for 3 consecutive years. So far, ethephon and Regalis have shown no or only minor additional beneficial effects compared to root pruning or trunk incision followed by root pruning in the years thereafter. Flowering, fruit yield and fruit quality of 'Conference' pears produced using the different strategies are presented and discussed

"Freedom of Movement within 'Fortress Europe'"

Introduction. Much attention has been focused on those seeking to enter ‘fortress Europe’ ­ whether the concept is understood to refer only to the EU Schengen countries or to include non-EU Schengen countries, the United Kingdom and Ireland, or the countries which joined the Union in May 2004. Yet internal mobility within ‘fortress Europe’ is at least as worthy of consideration. The rise of freedom of movement rights in Europe ­ now codified with the legal category of European Union citizenship ­ represents a startling reversal of the historical tradition of state sovereignty. States have historically been defined in terms of insiders (citizens) and outsiders (foreigners). The new supranational rights supersede this traditional distinction by reducing or even removing the ability of European states to discriminate between their own citizens and those of other EU member states. Borders within the European Union still matter, but the remaining barriers to freedom of movement within ‘fortress Europe’ are practical rather than legal, and even they are rapidly disappearing. Exceptions to the European free movement regime still exist ­ such as the case of individuals deemed to pose a significant threat to public health or public security. But the rights of free movement have now been extended to virtually all European citizens, even though there will be a phase-in period for workers from most of the new accession states. By contrast, third-country nationals ­ citizens neither of the host state (first country) nor of another EU member state (second country) but of a non-EU state ­ continue to be denied freedom of movement rights within the Union, despite the efforts of the Commission and some national governments to extend them the same rights as those enjoyed by EU citizens. Exceptions to Schengen also continue to exist, as with special events such as the European soccer cup, for which Portugal in 2004 (just as Belgium and the Netherlands in 2000) was granted a temporary exemption on the requirement to abstain from checking the identification of individuals crossing Portuguese borders. On the whole, however, the picture that emerges for freedom of movement within Europe is one of a continent in which Europeans can move about freely, and in which state borders (though clearly not the borders between ‘fortress Europe’ and the rest of the world!) have lost most of the significance they once possessed. This paper lays out the development of the Schengen system and places it within the context of European Union citizenship

Constructing non-perturbative gauges using correlation functions

Gauge fixing in the non-perturbative domain of non-Abelian gauge theories is obstructed by the Gribov-Singer ambiguity. To compare results from different methods it is necessary to resolve this ambiguity explicitly. Such a resolution is proposed using conditions on correlation functions for a family of non-perturbative Landau gauges. As a consequence, the various results available for correlation functions could possibly correspond to different non-perturbative Landau gauges, discriminated by an additional non-perturbative gauge parameter. The proposal, the necessary assumptions, and evidence from lattice gauge theory calculations, are presented in detail.Comment: in v2: Various modifications, discussion of results and scenario extended, references added in v3: Discussed definitions of what a Gribov ambiguity, a resolution of the ambiguity, and a Gribov problem is. Various minor improvement