CORRECTION OF ANGULAR DEFORMITY BY ASYMMETRIC PHYSEAL GROWTH AND BONE REMODELLING     

Terje O.  Fjeld  DVM  Harald  Steen  MD 《Veterinary radiology & ultrasound》1986,27(2):58-64

Angular deformities of 25 or 37 degrees valgus were created by transverse wedge osteotomies in the diaphysis of the radius in 3-month-old Cocker Spaniels. Spontaneous correction was judged from radiographs until skeletal maturity. The magnitude of correction was estimated, using the opposite normal leg as a control. Asymmetrical physeal growth corrected the induced angulation between the proximal and distal radial joint plane surfaces (joint plane angle). The average correction of the joint plane angle was 80% in the 25 degree group, and 72% in the 37 degree group. Bone remodeling of the radial shaft corrected the induced diaphyseal angulation by 50% in both groups during the study.  相似文献   

Economic utility of 3D remote sensing data for estimation of site index in Nordic commercial forest inventories: a comparison of airborne laser scanning,digital aerial photogrammetry and conventional practices     

Lennart Noordermeer  Terje Gobakken  Erik Næsset  Ole Martin Bollandsås 《Scandinavian Journal of Forest Research》2021,36(1):55-67

ABSTRACT

Forest productivity is a crucial variable in forest planning, usually expressed as site index (SI). In Nordic commercial forest inventories, SI is commonly estimated by a combination of aerial image interpretation, field assessment and information obtained from previous inventories. Airborne laser scanning (ALS) and digital aerial photogrammetry (DAP) data can alternatively be used for SI estimation, however the economic utilities of the inventory methods have not been compared. We compared seven methods of SI estimation in a cost-plus-loss analysis, by which we added the expected economic losses due to sub-optimal treatment decisions to the inventory costs. The methods comprised direct and indirect estimation from combinations of ALS, DAP and stand register data, and manual interpretation from aerial imagery supported by field assessment and information from previous inventories (conventional practices). The choice of method had great impact on both the accuracy and the economic value of the produced estimates. Direct methods using bitemporal ALS and DAP data gave the best accuracy and the smallest total cost. DAP was a suitable and low-cost data source for SI estimation. Estimation from single-date ALS and DAP data and age obtained from the stand register provided practical alternatives when applied to even-aged stands.  相似文献   

The effects of temporal differences between map and ground data on map-assisted estimates of forest area and biomass     

Ronald E. McRoberts  Erik Næsset  Terje Gobakken 《Annals of Forest Science》2016,73(4):839-847

  相似文献   

Short-term storage and cryopreservation of milt from Atlantic salmon and sea trout     

Joachim Stoss  Terje Refstie 《Aquaculture (Amsterdam, Netherlands)》1983,30(1-4):229-236

Experiments on short-term preservation of sperm were performed with Atlantic salmon (Salmo salar). Fertility was maintained for up to 10 days when 2 mm thick samples were stored at 0° C under an oxygen atmosphere in the presence of antibiotics (125 IU penicillin and 125 μg streptomycin per ml sperm). Fertility was completely lost after 24 days. Sperm stored without antibiotics fertilized 100% of eggs after 6 days.

Cryopreservation was carried out with milt from Atlantic salmon and sea trout (Salmo trutta). Semen mixed with extender was frozen on dry ice (pellets) with subsequent storage in liquid nitrogen. Sperm pellets were thawed in a 0.12-M NaHCO₃-solution (10° C) before insemination. The suitability of an extender as previously described by Stoss and Holtz and of a 0.3-M glucose solution with the addition of 10% DMSO, was tested on two different batches of sperm and eggs in Atlantic salmon and sea trout. In addition, the extender earlier reported by Mounib and an aqueous solution of 10% DMSO were only used in Atlantic salmon with one batch of gametes.

Insemination with cryopreserved Atlantic salmon sperm resulted in 36 to 91.3% eyed eggs (control = 100). The differences were caused by the type of extender and the batch of gametes employed. The very simple extender consisting of 0.3 M glucose and 10% DMSO only was the most successful. Results with cryopreserved sea trout sperm ranged between 38.6–54.8% eyed eggs, showing no difference between treatments.  相似文献   

Seasonal shift in spawning of Atlantic cod (Gadus morhua L.) by photoperiod manipulation: egg quality in relation to temperature and intensive larval rearing     

Terje van der Meeren  & Vladimir P Ivannikov 《Aquaculture Research》2006,37(9):898-913

Commercial intensive fry production of Atlantic cod will be dependent on production of viable eggs independent of season. This can only be done by manipulation of maturation by photoperiod, but little is known about potential effects on egg characteristics and larval viability. In two cod broodstocks, maturation was successfully advanced or delayed 6 months compared with normal spawning season (March–April) by manipulation of photoperiod. The advanced broodstock spawned both in spring and autumn the same year. In two of the spawning tanks during autumn, ambient temperature was reduced after reaching 13.7°C during the first half of the spawning period. Egg quality and viability were monitored, and several egg batches were incubated, hatched and start‐fed for examination of growth and survival. Temperatures above 9.6°C resulted in significant reductions in fertilization and normal egg development. Concurrently, fractions of dead and unfertilized eggs increased with elevated temperature. Actual relative fecundity was not affected by temperature. Egg characteristics improved when temperature was controlled and lowered below 9.6°C. Occurrence of irregular spawners suggests that handling of broodstock fish should be avoided during maturation and spawning. Cod larvae originating from eggs of the advanced or delayed broodstocks were successfully reared beyond metamorphosis. Survival was 9.0–46.6% and 29.3% in green and clear water respectively. Survival correlated with both initial and average feeding conditions, but growth rate did not correlate with either of survival and feeding conditions. Specific growth rates (8.3–13.6% day⁻¹) is comparable with other intensive rearing trials with cod, but were lower than reported from nature‐like systems.  相似文献   

Divergent, genetically based feeding behaviour of two sympatric Arctic charr, Salvelinus alpinus (L.), morphs   总被引：1，自引：0，他引：1  

A. Klemetsen  R. Knudsen  R. Primicerio  P.-A. Amundsen 《Ecology of Freshwater Fish》2006,15(3):350-355

Abstract –  Arctic charr, Salvelinus alpinus (L.), is one of the several northern fishes that show resource polymorphisms in postglacial lakes. Two reproductively isolated morphs of Arctic charr coexist in distinct ecological niches in the subarctic lake Fjellfrøsvatn, North Norway. Offspring of the two morphs (termed littoral charr and profundal charr) were reared separately but under identical conditions. Their feeding behaviour was compared experimentally using different kinds of live prey. The fishes had no experience with natural prey before the experiments. The littoral morph were more effective in eating live plankton ( Daphnia ) and littoral benthos ( Gammarus ), and had a higher attack rate against pleuston (surface prey, Gerris ) compared with the profundal morph. The two morphs behaved in accordance with expectations from their in situ niche utilisation towards the three prey types. This indicates a case of incipient ecological speciation where divergence in resource utilisation in contrasting niches has evolved adaptations in feeding behaviour by natural selection.  相似文献   

Mites of the genus Carabodes (Acari,Oribatida) in Norwegian coniferous forests: occurrence in different soils,vegetation types and polypore hosts     

Sigmund Hågvar  Terje Amundsen  Bjørn Økland 《Scandinavian Journal of Forest Research》2014,29(7):629-638

Oribatid mites (Acari) represent a considerable part of the biodiversity in Fennoscandian forests, but our knowledge about their habitat requirements is limited. We studied 10 Carabodes species in the forest floor of seven coniferous forest types, and in dead fruiting bodies (sporocarps) of 6 species of wood-living polypore fungi in southern Norway. The most common Carabodes species in soil were rare in sporocarps, and vice versa. The density of several ground-living species was significantly influenced by vegetation type and soil type. Carabodes willmanni and C. subarcticus were considered as lichen feeders on the ground, and occurred abundantly in Cladonia-rich pine forests. Three species, C. femoralis, C. areolatus and C. reticulatus, seem to be sporocarp specialists. Their relative numbers were rather similar in dead sporocarps of five different fungal species, including annual and perennial sporocarps, soft and hard. This was in contrast to beetles from the same sporocarps, which in a previous study proved to be strongly host-specific. Although being tolerant to different fungal species, the association of certain Carabodes species to dead sporocarps could make them vulnerable in forests with little dead wood and few sporocarps.  相似文献   

Culling prey promotes predator recovery--alternative states in a whole-lake experiment     

Persson L  Amundsen PA  De Roos AM  Klemetsen A  Knudsen R  Primicerio R 《Science (New York, N.Y.)》2007,316(5832):1743-1746

Many top-predator fish stocks in both freshwater and marine systems have collapsed as a result of overharvesting. Consequently, some of these communities have shifted into seemingly irreversible new states. We showed, for predators feeding on prey that exhibit food-dependent growth, that culling of fish prey may promote predator recovery. We removed old stunted individuals of a prey-fish species in a large, low-productive lake, which caused an increase in the availability of small-sized prey and allowed the predator to recover. The shift in community state has been sustained for more than 15 years after the cull ended and represents an experimental demonstration of an alternative stable state in a large-scale field system. Because most animals exhibit food-dependent growth, shifts into alternative stable states resulting from overcompensating prey growth may be common in nature and may require counterintuitive management strategies.  相似文献   

Dynamics of mammalian chromosome evolution inferred from multispecies comparative maps     

Murphy WJ  Larkin DM  Everts-van der Wind A  Bourque G  Tesler G  Auvil L  Beever JE  Chowdhary BP  Galibert F  Gatzke L  Hitte C  Meyers SN  Milan D  Ostrander EA  Pape G  Parker HG  Raudsepp T  Rogatcheva MB  Schook LB  Skow LC  Welge M  Womack JE  O'brien SJ  Pevzner PA  Lewin HA 《Science (New York, N.Y.)》2005,309(5734):613-617

The genome organizations of eight phylogenetically distinct species from five mammalian orders were compared in order to address fundamental questions relating to mammalian chromosomal evolution. Rates of chromosome evolution within mammalian orders were found to increase since the Cretaceous-Tertiary boundary. Nearly 20% of chromosome breakpoint regions were reused during mammalian evolution; these reuse sites are also enriched for centromeres. Analysis of gene content in and around evolutionary breakpoint regions revealed increased gene density relative to the genome-wide average. We found that segmental duplications populate the majority of primate-specific breakpoints and often flank inverted chromosome segments, implicating their role in chromosomal rearrangement.  相似文献   

Shooting range contamination: mobility and transport of lead (Pb), copper (Cu) and antimony (Sb) in contaminated peatland     

Gudny Okkenhaug  Andreas Botnen Smebye  Thomas Pabst  Carl Einar Amundsen  Hilmar Sævarsson  Gijs D. Breedveld 《Journal of Soils and Sediments》2018,18(11):3310-3323

  相似文献