Short-term Response of Breeding Barred Owls to Forestry in a Boreal Mixedwood Forest Landscape

Forestry and other activities are increasing in the boreal mixedwood of Alberta, with a concomitant decrease in older forest. The Barred Owl (Strix varia) is an old-growth indicator species in some jurisdictions in North America. Hence, we radio-tagged Barred Owls in boreal mixedwood in Alberta to determine whether harvesting influenced habitat selection. We used three spatial scales: nest sites, i.e., nest tree and adjacent area of 11.7 m radius around nests, nesting territory of 1000 m radius around nests, and home range locations within 2000 m radius of the home range center. Barred Owls nested primarily in balsam poplar (Populus balsamifera) snags > 34 cm dbh and nest trees were surrounded by large, > 34 cm dbh, balsam poplar trees and snags. Nesting territories contained a variety of habitats including young < 80-yr-old, deciduous-dominated stands, old deciduous and coniferous-dominated stands, treed bogs, and recent clear-cuts. However, when compared to available habitat in the study area, they were more likely to contain old conifer-dominated stands and recent cutblocks. We assumed this is because all of the recent harvest occurred in old stands, habitat preferred by the owls. When compared with random sites, locations used for foraging and roosting at the home range scale were more likely to be in young deciduous-dominated stands, old conifer-dominated stands and cutblocks > 30 yr old, and less likely to occur in old deciduous-dominated stands and recent cutblocks. Hence, although recent clearcuts occurred in territories, birds avoided these microhabitats during foraging. To meet the breeding requirements of Barred Owls in managed forests, 10–20 ha patches of old deciduous and mixedwood forest containing large Populus snags or trees should be maintained. In our study area, nest trees had a minimum dbh of 34 cm. Although cut areas were incorporated into home ranges, the amount logged was low, i.e., 7%, in our area. Hence more research is required to determine harvest levels tolerated by owls over the long term.

Effects of short-term pH fluctuations on cadmium, nickel, lead, and zinc availability to ryegrass in a sewage sludge-amended field

In this field experiment, sewage sludge was applied at 0, 5, 10, and 50 t ha(-1), and the availability of Cd, Ni, Pb, and Zn was assessed both by ryegrass uptake and by DTPA extractions. The aim was to investigate the role of important soil parameters, particularly pH, on heavy metal availability. It was found that metal uptake and extractability increased significantly in the 50 t ha(-1) treatment. In the 16th week of the experiment there was a significant, although temporary, increase in DTPA-extractable Cd, Ni, and Zn concentrations. Metal concentrations in ryegrass were also significantly elevated in week 20 compared to the subsequent cuttings. These fluctuations in both DTPA and ryegrass uptake occurred only at 50 t ha(-1) and were probably induced by a sudden pH decrease measured in the same treatment in week 16. This suggests that soils which have received high applications of sewage sludge may be prone to fluctuations in metal availability. (c) 2007 Elsevier Ltd. All rights reserved.

Short-term effects of manipulated increase in acid deposition on soil, soil solution chemistry and fine roots in Scots pine (Pinus sylvestris) stand on a podzol

A manipulated increase in acid deposition (15 kg S ha(-1)), carried out for three months in a mature Scots pine (Pinus sylvestris) stand on a podzol, acidified the soil and raised dissolved Al at concentrations above the critical level of 5 mg l(-1) previously determined in a controlled experiment with Scots pine seedlings. The induced soil acidification reduced tree fine root density and biomass significantly in the top 15 cm of soil in the field. The results suggested that the reduction in fine root growth was a response not simply to high Al in solution but to the depletion of exchangeable Ca and Mg in the organic layer, K deficiency, the increase in NH4:NO3 ratio in solution and the high proton input to the soil by the acid manipulation. The results from this study could not justify the hypothesis of Al-induced root damage under field conditions, at least not in the short term. However, the study suggests that a short exposure to soil acidity may affect the fine root growth of mature Scots pine.

Process planning methodology: dynamic short-term planning for off-site construction in Slovenia

Planning is a vital element of project management but it is still not recognized as a process variable. Its objective should be to outperform the initially defined processes, and foresee and overcome possible undesirable events. Detailed task-level master planning is unrealistic since one cannot accurately predict all the requirements and obstacles before work has even started. The process planning methodology (PPM) has thus been developed in order to overcome common problems of the overwhelming project complexity. The essential elements of the PPM are the process planning group (PPG), including a control team that dynamically links the production/site and management, and the planning algorithm embodied within two continuous-improvement loops. The methodology was tested on a factory project in Slovenia and in four successive projects of a similar nature. In addition to a number of improvement ideas and enhanced communication, the applied PPM resulted in 32% higher total productivity, 6% total savings and created a synergistic project environment.

The effects of a short-term increase in supplementation on the reproduction performance in lactating crossbred dairy cows

The hypothesis that dairy cows partially suckling their calves would ovulate following removal of calves when restored to positive energy balance by a short-term increase in supplementation was investigated in 65 crossbred cows. Five treatments (T1, T2, T3, T4, and T5) that differed in the amount of total concentrate fed from calving to week 24 were involved. Calves were allowed to suck residual milk to 12 weeks of age. Energy balance was estimated by measuring intake, milk yield and organic matter digestibility. The occurrence of ovulation was determined by the analysis of milk progesterone (P4) concentration. Four groups that were receiving additional supplementation were restored to positive energy balance, while the control group (T I) remained in negative energy balance. The percentage of cows ovulating was 36%, 58%, 92%, 90% and 60% for T1, T2, T3, T4 and T5, respectively (P = 0.026). Comparison of the timing of ovulation for combined results from T1+T2 and T3+T4+T5 estimated mean time to fail to ovulate as 110 +/- 9.0 and 87 +/- 7.6 days, respectively (p = 0.023). The percentage of the cows showing oestrus was 9%, 8%, 33%, 40% and 40% for T1, T2, T3, T4 and T5, respectively (P = 0.197). Short-term increases in supplementation are unlikely to be an attractive means of reducing calving intervals.

Temporal interval production and short-term memory

Interference with time estimation from concurrent nontemporal processing has been shown to depend on the short-term memory requirements of the concurrent task (Fortin Breton, 1995; Fortin, Rousseau, Bourque, & Kirouac, 1993). In particular, it has been claimed that active processing of information in short-term memory produces interference, whereas simply maintaining information does not. Here, four experiments are reported in which subjects were trained to produce a 2,500-msec interval and then perform concurrent memory tasks. Interference with timing was demonstrated for concurrent memory tasks involving only maintenance. In one experiment, increasing set size in a pitch memory task systematically lengthened temporal production. Two further experiments suggested that this was due to a specific interaction between the short-term memory requirements of the pitch task and those of temporal production. In the final experiment, subjects performed temporal production while concurrently remembering the durations of a set of tones. Interference with interval production was comparable to that produced by the pitch memory task. Results are discussed in terms of a pacemaker-counter model of temporal processing, in which the counter component is supported by short-term memory.

Short-term memory and the attentional blink: capacity versus content

When people monitor the rapid serial visual presentation (RSVP) of stimuli for two targets (T1 and T2), they often miss T2 if it falls into a time window of about half a second after T1 onset, a phenomenon known as the attentional blink (AB). We found that overall performance in an RSVP task was impaired by a concurrent short-term memory (STM) task and, furthermore, that this effect increased when STM load was higher and when its content was more task relevant. Loading visually defined stimuli and adding articulatory suppression further impaired performance on the RSVP task, but the size of the AB over time (i.e., T1-T2 lag) remained unaffected by load or content. This suggested that at least part of the performance in an RSVP task reflects interference between competing codes within STM, as interference models have held, whereas the AB proper reflects capacity limitations in the transfer to STM, as consolidation models have claimed.

Speech perception and phonological short-term memory capacity in language impairment: preliminary evidence from adolescents with specific language impairment (SLI) and autism spectrum disorders (ASD)

Background: The cognitive bases of language impairment in specific language impairment (SLI) and autism spectrum disorders (ASD) were investigated in a novel non-word comparison task which manipulated phonological short-term memory (PSTM) and speech perception, both implicated in poor non-word repetition. Aims: This study aimed to investigate the contributions of PSTM and speech perception in non-word processing and whether individuals with SLI and ASD plus language impairment (ALI) show similar or different patterns of deficit in these cognitive processes. Method & Procedures: Three groups of adolescents (aged 14–17 years), 14 with SLI, 16 with ALI, and 17 age and non-verbal IQ matched typically developing (TD) controls, made speeded discriminations between non-word pairs. Stimuli varied in PSTM load (two- or four-syllables) and speech perception load (mismatches on a word-initial or word-medial segment). Outcomes & Results: Reaction times showed effects of both non-word length and mismatch position and these factors interacted: four-syllable and word-initial mismatch stimuli resulted in the slowest decisions. Individuals with language impairment showed the same pattern of performance as those with typical development in the reaction time data. A marginal interaction between group and item length was driven by the SLI and ALI groups being less accurate with long items than short ones, a difference not found in the TD group. Conclusions & Implications: Non-word discrimination suggests that there are similarities and differences between adolescents with SLI and ALI and their TD peers. Reaction times appear to be affected by increasing PSTM and speech perception loads in a similar way. However, there was some, albeit weaker, evidence that adolescents with SLI and ALI are less accurate than TD individuals, with both showing an effect of PSTM load. This may indicate, at some level, the processing substrate supporting both PSTM and speech perception is intact in adolescents with SLI and ALI, but also in both there may be impaired access to PSTM resources.