4 resultados para felling hinge

em CentAUR: Central Archive University of Reading - UK


Relevância:

10.00% 10.00%

Publicador:

Resumo:

Hunting foxes with hounds has been a countryside pursuit in Britain since the 17th Century, but its effect nationally on habitat management is little understood by the general public. A survey questionnaire was distributed to 163 mounted fox hunts of England and Wales to quantify their management practices in woodland and other habitat. Ninety-two hunts (56%), covering 75,514 km(2), returned details on woodland management motivated by the improvement of their sport. The management details were verified via on-site visits for a sample of 200 woodlands. Following verification, the area of woodlands containing the management was conservatively estimated at 24,053 (+/- 2241) ha, comprising 5.9% of woodland area within the whole of the area hunted by the 92 hunts. Management techniques included: tree planting, coppicing, felling, ride and perimeter management. A case study in five hunt countries in southern England examined, through the use of botanical survey and butterfly counts, the consequences of the hunt management on woodland ground flora and butterflies. Managed areas had, within the last 5 years, been coppiced and rides had been cleared. Vegetation cover in managed and unmanaged sites averaged 86% and 64%, respectively, and managed areas held on average 4 more plant species and a higher plant diversity than unmanaged areas (Shannon index of diversity: 2.25 vs. 1.95). Both the average number of butterfly species (2.2 vs. 0.3) and individuals counted (4.6 vs. 0.3) were higher in the managed than unmanaged sites.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

The notification of the level of domestic support to the World Trade Organization (WTO) is intended to reflect compliance with obligations entered into at the time of the Uruguay Round. WTO members have often been slow to provide notification of domestic support levels. This makes the process of notification less useful as an indicator of the degree to which changes in policy have or have not benefited the trade system as a whole and exporting countries in particular. The notification of domestic support in the E.U. illustrates the value of a measure that reflects current policies and can therefore act as a basis for negotiation of further disciplines where these are necessary. The E.U. has made major changes in its Common Agricultural Policy (CAP) over the period since 1992 when the MacSharry reforms were implemented. Payments originally notified in the blue box (related to supply control) have over time been changed until in their present form they are unrelated to current production or price levels, and hence can satisfy the criteria for the green box. The E.U. has therefore much more latitude in trade talks to agree to reductions in the allowable trade-distorting support. This paper reproduced the E.U. notifications relating to 2003/04 and extends these with official statistics to the year 2006/07. It then projects forward the components of domestic support until the year 2013/14, based on forecasts of future production and estimates of policy parameters. The impact of a successful Doha Round is simulated, showing that the constraints envisaged in the WTO draft modalities document of May 19, 2008, would be binding by the year 2013, at about the time the next budget cycle in the E.U. starts. Without the Doha Round constraints, further reform might still happen for domestic reasons, but the framework provided by the WTO for domestic policy spending would be less relevant. In that case, much could hinge on the legitimacy of the Single Farm Payment system under the current rules governing the green box.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Side chain liquid crystal polymers and elastomers exhibit a rich phase behaviour which arises from the antagonistic influences of the entropically disordered polymer chain configuration and the long range orientational ordering of the mesogenic units. This competition arises since the natural macroscopic phase separation is inhibited by the inherent chemical connectivity of the system. At the heart of this connectivity is the spacer link and we consider here its influence on the phase behaviour. In particular we consider a series of elastomers in which the number of alkyl units in the spacer is systematically varied from 2 to 6. The lengthening of the coupling spacer is accompanied by an alternation of the sign of coupling between the polymer chain and the mesogenic unit. These results demonstrate the dominating influence of the so-called hinge effect in determining the phase behaviour. In addition to the alternation of the sign there is some decrease in the magnitude of the coupling with increasing spacer length.

Relevância:

10.00% 10.00%

Publicador:

Resumo:

Mutations in leucine-rich repeat kinase 2 (LRRK2) are the most common cause of Parkinson's disease (PD). LRRK2 contains a Ras of complex proteins (ROC) domain that may act as a GTPase to regulate its protein kinase activity. The structure of ROC and the mechanism(s) by which it regulates kinase activity are not known. Here, we report the crystal structure of the LRRK2 ROC domain in complex with GDP-Mg2+ at 2.0-Å resolution. The structure displays a dimeric fold generated by extensive domain-swapping, resulting in a pair of active sites constructed with essential functional groups contributed from both monomers. Two PD-associated pathogenic residues, R1441 and I1371, are located at the interface of two monomers and provide exquisite interactions to stabilize the ROC dimer. The structure demonstrates that loss of stabilizing forces in the ROC dimer is likely related to decreased GTPase activity resulting from mutations at these sites. Our data suggest that the ROC domain may regulate LRRK2 kinase activity as a dimer, possibly via the C-terminal of ROC (COR) domain as a molecular hinge. The structure of the LRRK2 ROC domain also represents a signature from a previously undescribed class of GTPases from complex proteins and results may provide a unique molecular target for therapeutics in PD.