Direct seeding to restore rainforest species: Microsite effects on the early establishment and growth of rainforest tree seedlings on degraded land in the wet tropics of Australia

Reforestation in tropical areas is usually attempted by planting seedlings but, direct seeding (the artificial addition or sowing of seed) may be an alternative way of accelerating forest recovery and successional processes. This study investigated the effects of various sowing treatments (designed to create different microsite conditions for seed germination) and seed sizes on the early establishment and growth of directly sown rainforest tree species in a variety of experimental plots at three sites in the wet tropical region of north-cast Queensland, Australia. The different sowing treatments were found to have significant effects on seedling establishment. Broadcast sowing treatments were ineffective and resulted in very poor seedling establishment and high seed wastage. Higher establishment rates occurred when seeds were buried. Seed size was found to be an important factor affecting establishment in relation to micro-site condition. In general, larger seeded species had higher establishment rates at all three sites than species of small and intermediate seed size, but only in sowing treatments where seeds were buried. Overall these results suggest that direct sowing of seed can be used as a too] to accelerate recolonisation of certain rainforest tree species on degraded tropical lands, but initial success will be dependent on the choice of sowing method and its suitability for the seed types selected. The results also indicate that the recruitment of naturally dispersed tree species at degraded sites is likely to be severely limited by the availability of suitable microsites for seed germination. Consequently the natural recovery of degraded sites via seed rain can be expected to be slow and unpredictable, particularly in areas where soil compaction has occurred. (c) 2006 Elsevier B.V. All rights reserved.

Load during prosthetic gait : is direct measurement better than inverse dynamics?

The knee forces and moments estimated by inverse dynamics and directly measured by a multiaxial transducer were compared during the gait of a transfemoral amputee. The estimated and directly measured forces and moments were relatively close. However, 3D inverse dynamics estimated only partially the forces and moments associated with the deformation of the prosthetic foot and locking of knee mechanism.

Loading applied on prosthetic knee of transfemoral amputee: comparison of inverse dynamics and direct measurements

Inverse dynamics is the most comprehensive method that gives access to the net joint forces and moments during walking. However it is based on assumptions (i.e., rigid segments linked by ideal joints) and it is known to be sensitive to the input data (e.g., kinematic derivatives, positions of joint centres and centre of pressure, inertial parameters). Alternatively, transducers can be used to measure directly the load applied on the residuum of transfemoral amputees. So, the purpose of this study was to compare the forces and moments applied on a prosthetic knee measured directly with the ones calculated by three inverse dynamics computations - corresponding to 3 and 2 segments, and « ground reaction vector technique » - during the gait of one patient. The maximum RMSEs between the estimated and directly measured forces (i.e., 56 N) and moment (i.e., 5 N.m) were relatively small. However the dynamic outcomes of the prosthetic components (i.e., absorption of the foot, friction and limit stop of the knee) were only partially assessed with inverse dynamic methods.

Direct and indirect effects of egg parasitism by Neopolyscystus Girault sp. (Hymenoptera: Pteromalidae) on Paropsis atomaria Olivier (Coleoptera: Chrysomelidae)

Abstract Neopolycystus sp. is the only primary egg parasitoid associated with the pest beetle Paropsis atomaria in subtropical eucalypt plantations, but its impact on its host populations is unknown. The simplified ecosystem represented by the plantation habitat, lack of interspecific competition for host and parasitoid, and the multivoltinism of the host population makes this an ideal system for quantifying the direct and indirect effects of egg parasitism, and hence, effects on host population dynamics. Within-, between- and overall-egg-batch parasitism rates were determined at three field sites over two field seasons, and up to seven host generations. The effect of exposure time (egg batch age), host density proximity to native forest and water sources on egg parasitism rates was also tested. Neopolycystus sp. exerts a significant influence on P. atomaria populations in Eucalyptus cloeziana. plantations in south-eastern Queensland, causing the direct (13%) and indirect (15%) mortality of almost one-third of all eggs in the field. Across seasons and generations, 45% of egg batches were parasitised, with a within-batch parasitism rate of around 30%. Between-batch parasitism increased up to 5–6 days after oviposition in the field, although within-batch parasitism rates generally did not. However, there were few apparent patterns to egg parasitism, with rates often varying significantly between sites and seasons.

Tax morale and direct democracy

This paper analyses the impact of direct democracy on tax morale in Switzerland, a country where participation rights strongly vary across different cantons, using survey data from the International Social Survey Programme (ISSP) 1998. The findings suggest that direct democratic rights have a significantly positive effect on tax morale.

Use of micro-ATR/FTIR imaging to study heterogeneous polymer oxidation by direct solvent casting onto the ATR IRE

A technique is described whereby micro-ATR/FTIR imaging can be used to follow polymer degradation reactions in situ in real time. The internal reflection element (IRE) assembly is removed from the ATR objective and polymer is solvent cast directly onto the IRE surface. The polymer is then subjected to degradation conditions and molecular structural changes monitored by periodically replacing the IRE assembly back in the ATR objective and collecting spectra which can be used to construct images. This approach has the benefit that the same part of the sample is always studied, and that contact by pressure which might damage the polymer surface is not required. The technique is demonstrated using the polymer Topas which was degraded by exposure to UVC light in air.

Direct and indirect effects on households’ intentions to replace the old car

With the purpose of testing the hypothesis that households’ intentions to replace their old car have a direct negative relationship to its perceived quality (‘current level’) and a direct positive relationship to their aspirations for a new car (‘aspiration level’), a rotating panel of car owners were interviewed every fourth month during 2 years. In this data set the hypothesis received support. In addition the results showed that the age of the car, the total number of miles driven, and the number of anticipated repairs affected the current level, whereas marital status, the number of children, consumer confidence, and environmental concern affected the aspiration level.