Operational impacts to residual stands following ground-based skidding in Hyrcanian Forest, northern Iran

Hyrcanian （Caspian） Forest in northern Iran has a richness of biological diversity, with endemic and endangered species. The usage of ground-based skidding is well accepted practice for the extraction of timber from the forest, but this operation has tended to cause the greatest environmental problems. The aims of the study were to evaluate and comparison of operational impacts, residual stand damage, regeneration, and to quantify these effects such as： the extent of the damage, wounding patterns, size and distribution after logging operations that utilized two different methods： short log and long log. A Timbetjack cable skidder was used and the study location was in the Kheyrud Forest. Post harvesting assessment of damage to the residual stand was compared along skid trail by 100% inventory method and also for the assessment of regeneration damage along winching strips. The results show that along winching strips the percentage of damage to the regeneration was 44% and 36%, while the tree damages along skid trails reached 2.3% and 4.1% in the short log and long log methods, respectively. The greatest average amount of damage to a bole occurred along the first 1 m up from the ground （97%） and also within 4 m of the skidder centerline （80%）. These results show that the short log method causes less damage to the residual stand than the longog method. Tree location to skidder trail appears to have a significant effect on the number and height of scars on a tree. Well designed and constructed trails should be wide enough to allow wood extraction from the forest. Damage to the residual stand might be reduced by proper planning and training of logging crews.

The impact of operative timing on clinical outcomes in elderly hip fracture

Objective To study the effect of operative timing on clinical outcomes in elderly hip fracture.Methods Two hundred sixty-seven patients with hip fracture were treated from July 2006 to May 2008.The patients who had an operation within

Analysis of aerobic granular sludge formation based on grey system theory

Based on grey entropy analysis, the relational grade of operational parameters with aerobic granular sludge＇s granulation indicators was studied. The former consisted of settling time （ST）, aeration time （AT）, superficial gas velocity （SGV）, height/diameter （H/D） ratio and organic loading rates （OLR）, the latter included sludge volume index （SVI） and set-up time. The calculated result showed that for SVI and set-up time, the influence orders and the corresponding grey entropy relational grades （GERG） were： SGV （0.9935） 〉 AT （0.9921） 〉 OLR （0.9894） 〉 ST （0.9876） 〉 H/D （0.9857） and SGV （0.9928） 〉 H/D （0.9914） 〉 AT （0.9909） 〉 OLR （0.9897） 〉 ST （0.9878）. The chosen parameters were all key impact factors as each GERG was larger than 0.98. SGV played an important role in improving SVI transformation and facilitating the set-up process. The influence of ST on SVI and set-up time was relatively low due to its dual functions. SVI transformation and rapid set-up demanded different optimal I-I/D ratio scopes （10-20 and 16-20）. Meanwhile, different functions could be obtained through adjusting certain factors＇ scope.