THE DORSOPROXIMAL-DORSODISTAL PROJECTION OF THE DISTAL CARPAL BONES IN HORSES: AN EVALUATION OF DIFFERENT BEAM-CASSETTE ANGLES     

Henrik  Uhlhorn  DVM  Per  Eksell  DVM 《Veterinary radiology & ultrasound》1999,40(5):480-485

To estimate the extent of the third carpal bone (C3) visible for evaluation in the dorsoproximal-dorsodistal oblique projection of the distal row of carpal bones, 13 forelimbs collected at post mortem from 7 horses were examined radiographically. The limbs were frozen with the carpal joints flexed then radiographed using fixed beam-cassette angles of 15 degrees to 45 degrees, at 5 degree intervals. The influence of beam-cassette angle on; the depth of the proximal articular surface examined, the radiographic appearance of C3 and the assessment of subchondral sclerosis was evaluated. Beam-cassette angles of 25 degrees to 40 degrees produced subjectively acceptable radiographs and did not appear to influence assessments of sclerosis. The mean depth of the examined proximal articular surface of the C3 increased significantly with each 5 degree increase in beam-cassette angle up to 40 degrees. The use of beam-cassette angles >35 degrees is recommended for the DPr-DDiO projection.  相似文献   

Small forest patches as pollinator habitat: oases in an agricultural desert?     

Proesmans  Willem  Bonte  Dries  Smagghe  Guy  Meeus  Ivan  Decocq  Guillaume  Spicher  Fabien  Kolb  Annette  Lemke  Isgard  Diekmann  Martin  Bruun  Hans Henrik  Wulf  Monika  Van Den Berge  Sanne  Verheyen  Kris 《Landscape Ecology》2019,34(3):487-501

Landscape Ecology - Small forest fragments are often the most abundant type of semi-natural habitat in intensive agricultural landscapes. Wild pollinators can use these forest patches as nesting or...  相似文献   

Fishing profiles of Danish seiners and bottom trawlers in relation to current EU management regulations          下载免费PDF全文

T. Noack  R. P. Frandsen  K. Wieland  L. A. Krag  F. Berg  N. Madsen 《Fisheries Management and Ecology》2017,24(6):436-445

Danish seines and bottom trawls operate differently and have different catching processes. Both gears belong to the same legislative category in European fisheries, but different management strategies in other countries and criticism by fishers on grouping Danish seines and trawls together indicate disagreement on current gear classification. This study compared both gears in terms of their fishing characteristics and catches of commercial species based on 16 years of observer data. Danish seining is a specialised fishing method that targeted few species but with higher total catch rates than bottom trawlers. Bottom trawling is a more all‐purpose fishing method that targets a larger number of species, and bottom trawlers use larger engines than Danish seiners. A generalised additive mixed model indicated that catch rates of flatfish are generally higher for Danish seines, and catch rates of roundfish species are higher for trawlers. The results do not directly suggest a separation of the gears in terms of legislation as the quantities of fish below current minimum size were similar, but for example future survival studies may reach different conclusions. Additional factors were found to be important in determining catches of both gears.  相似文献   

Degradation of mecoprop at different concentrations in surface and sub-surface soil     

Trine K. Reffstrup  Henrik Srensen  Arne Helweg 《Pest management science》1998,52(2):126-132

Biodegradation of [ring-¹⁴C] mecoprop (2-(4-chloro-2-methylphenoxy)propionic acid) was determined in surface and sub-surface soil at concentrations of 0·0005, 0·05, 0·5, 5, 50, 500, 5000 and 25000 mg kg^-1. The kinetics of mineralisation were evaluated from the mineralisation rates as a function of time and by non-linear regression analysis. In the sub-surface soil, degradation was 6–8 times slower than in surface soil, but the shape of the curves was the same in both layers. At concentrations between 0·0005 and 0·5 mg kg^-1, in both surface and sub-surface soil, degradation was initially zero-order followed by first-order kinetics. At 5 to 500 mg kg^-1 in surface soil and 5 to 50 mg kg^-1 in sub-surface soil the degradation rate was initially either constant or decreasing followed by exponential degradation indicating increasing populations of mecoprop decomposers in the soil. At 5000 and 25000 mg kg^-1 in the surface soil and at 500, 5000 and 25000 mg kg^-1 in the sub-surface soil, the degradation was negligible, as determined by the percentage [¹⁴C] carbon dioxide evolved. By non-linear regression, the three-half order model was found to describe the mineralisation. © 1998 SCI  相似文献   

Effects of habitat fragmentation on Eurasian red squirrel (Sciurus vulgaris) in a forest landscape     

Annika E. Delin  Henrik Andrén 《Landscape Ecology》1999,14(1):67-72

We studied the effects of habitat fragmentation, measured as forest stand size and isolation, on the distribution of Eurasian red squirrels (Sciurus vulgaris). Squirrel density was surveyed during four years in 46 forest stands (0.1–500 ha) in a forest landscape in south-central Sweden. The only factor that significantly influenced a density index was the proportion of spruce within a habitat fragment. Neither fragment size nor degree of isolation were significant. Furthermore, none of the interactions with year were significant, suggesting the same pattern in all four years. Thus, the effect of habitat fragmentation in this study seems to be only pure habitat loss, i.e. halving the proportion of preferred habitat in the landscape should result in a halving of the red squirrel population. Therefore, the landscape can be viewed as functionally continuous for the squirrels, although the preferred habitat was divided into fragments. The most likely explanation for the difference between this study and other studies on squirrels that found effects due to habitat fragmentation is a combination of shorter distances and less hostile surroundings in our study area. To identify landscape effects requires multiple studies because single studies usually consider only one landscape.  相似文献   

über den Einflusz der Seeregulierung auf den umgebenden Wald     

Henrik Hesselmann 《European Journal of Forest Research》1930,52(7-8):223-229

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Henrik Hesselmann 《Forstwissenschaftliches Centralblatt》1930,52(7-8):223-229

Ohne Zusammenfassung  相似文献