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181.
182.
Imke Janssen Jan-Hein Swagemakers Marc Koene Christoph Lischer 《Journal of Equine Veterinary Science》2013
This case report demonstrates the development and management of an osseous cyst-like lesion in the spongiosa of the navicular bone in a high-level show jumper with chronic intermittent forelimb lameness. The first evidence of navicular bone pathology was increased signal intensity on fat-suppressed images in the medulla of the right navicular bone, which progressed to a cystic lucency identified on radiographs at 24 months. The horse's progress was documented over a period of 2 years and 2 months, including lameness investigation, treatment, radiographs, and six follow-up standing low-field magnetic resonance imagings. At the last clinical recheck, the horse showed no signs of lameness and continued to compete in show jumping at an international level event. 相似文献
183.
Christoph Mans 《Journal of Exotic Pet Medicine》2013,22(2):141-162
The diagnosis and treatment of digestive system disorders in reptile species continues to provide challenges owing to the differences in anatomy and physiology in this diverse group of animals. Continued research efforts into diagnostic techniques, in particular imaging (e.g., contrast radiography and ultrasonography), of gastrointestinal tract have resulted in clinical advancements for practicing veterinarians. The aim of this article is to provide veterinarians up-to-date and clinically relevant summaries on the diagnosis and therapy of digestive system disorders of reptiles commonly maintained as companion animals. 相似文献
184.
Karsten Wesche Benjamin Krause Heike Culmsee Christoph Leuschner 《Biological conservation》2012,150(1):76-85
There is growing concern that biodiversity loss in European agricultural landscapes is having negative effects on functional trait diversity. Long-term studies examining vegetation changes from the period before agricultural industrialisation are however rare. Here, we ask how management intensification and increased nutrient input initiated in the 1950/1960s have altered grassland plant community composition, species diversity and functional trait composition using comprehensive datasets from five floodplain regions (plus one protected reference region) in northern Germany. Sites with available historical relevés and vegetation maps (1950/1960s, 1990s) were resampled in 2008 to facilitate the analysis of a period spanning four to five decades.Plant community composition changed tremendously in all study regions during the 50 year period, which was related to increasing Ellenberg indicator values for nutrient availability. Species richness at the plot-level fell by 30–50% over the period, and losses in functional diversity were equally large. A non-formal comparison with the results from the protected reference study region indicates that the changes may mostly be attributable to local nutrient input rather than to supra-regional climate change. Our results indicate a consistent trend towards much more species-poor communities dominated by mow-tolerant, N-demanding competitive grasses, whereas species with more ruderal strategies, species flowering early in the season and, in particular, insect-pollinated herbs have all decreased. The substantial loss of nectar-producing grassland herbs is likely to have negative effects on the abundance of pollinating insects, with consequences for the grassland animal communities. This highlights the growing need for adequate grassland management schemes with low N input to preserve high-nature-value grassland. 相似文献
185.
Anika Hudewenz Alexandra-Maria Klein Christoph Scherber Lea Stanke Teja Tscharntke Anja Vogel Alexandra Weigelt Wolfgang W. Weisser Anne Ebeling 《Biological conservation》2012,150(1):42-52
Agricultural intensification is a major driver of global environmental change. Disentangling the relative impact of losses in plant species richness and intensified management on higher trophic level organisms is important for conservation recommendations.We established different management regimes along an experimental gradient of plant species richness within “The Jena-Experiment” in Germany and quantified herbivory as well as grasshoppers and pollinators. Herbivory, grasshopper density and species richness and frequency of flower visiting pollinators were recorded two times in each of four subplots of altogether 80 plots differing in plant species richness. Each of the four subplots was subject to four different levels of fertilizer application and mowing to simulate very low, low, high and very high land use intensity.Fertilization and mowing significantly affected plant–herbivore interactions but plant species richness had no discernible effect. Grasshoppers were most abundant at high intensity subplots (3.1 individuals per m2) and least abundant on very low intensity subplots (1.3 individuals per m2). Leaf damage caused by herbivores was highest in even the very high intensity subplots (3.7%) with four mowing events per year and high amounts of fertilizer application and lowest on subplots with a low management intensity (2.4%) comprising two mowing events per year but no fertilizer application. In contrast, pollinators benefited most from lower management intensities, with only one or two mowing events and no fertilizer addition. In addition, higher numbers of flowering plant species and increased blossom cover was associated with enhanced pollinator species richness and flower visitation.Our results indicate that even in grasslands with high plant species richness, mowing and fertilization are more important drivers of herbivory and flower visitation by pollinators. Management with no more than two cuts per year and without fertilizer application in our grasslands balanced the ecosystem functions of increased pollination and decreased herbivory. 相似文献
186.
Viktor W. Svinger Tomas Policar Christoph Steinbach Simona Polakova Antonin Jankovych Jan Kouril 《Aquaculture International》2013,21(4):783-799
Effects of physiological saline (PS)-dissolved or Freund′s incomplete adjuvant (FIA)-emulsified sGnRHa on the induction and advancement of ovulation in brook char were assessed. Two-year-old females were randomly divided into 5 groups. Groups A and B received intraperitoneal injection of FIA-emulsified sGnRHa (sGnRHa-FIA) at dosages of 50 and 25 μg kg?1 body weight (BW), respectively. Females in group C were treated with a double injection (DI) of PS-dissolved sGnRHa (sGnRHa-PS) at 25 μg kg?1 BW spaced 3 days apart. Fish in group D received a 25 μg kg?1 BW single injection (SI) of sGnRHa-PS. Group E was established as a control group. After stripping, ovarian plasma pH level was measured, and an egg sample was taken from each female to record egg weight and diameter and survival to the eyed stage. Females in the GnRHa-treated groups ovulated significantly earlier than did females in the control group (P < 0.01). No significant differences were found among GnRHa-treated groups in ovulation dynamics and mean time to ovulation. Ovarian fluid pH was significantly higher in groups A, B, and C compared to control group E (P < 0.05). Significantly lower egg weight was found only in group B (P < 0.01), although all advanced groups tended to have lower egg weight than the control group. Egg diameters paralleled egg weight. Survival to the eyed stage was significantly higher in GnRHa-advanced groups compared to the control. A negative relationship was found between egg weight end eyed eggs percent (R 2 = 0.26). No pre-spawning or post-spawning mortality was observed during a 6-month period. Neither sGnRHa-PS nor sGnRHa-FIA are associated with negative influences on the health of females. The sGnRHa-FIA injections proved to exhibit the same efficacy as the DI protocol with sGnRHa-PS. Although no statistical differences were found in ovulation dynamics, we do not recommend the use of SI with sGnRHa-PS in brook char. 相似文献
187.
Interpretation of the oxygen isotopic signature of soil-derived N2O may be flawed when it is based on reaction stoichiometry and fractionation alone. In fact, oxygen (O) exchange between H2O and intermediates of N2O production pathways may largely determine this O isotopic signature. Although in our previous work we conclusively proved the occurrence of O exchange during N2O production by denitrification of NO3−, its occurrence in N2O production pathways by nitrifiers remains unclear. The aim of this study was to examine the likeliness of O exchange during various stages of N2O production in soil via nitrification, nitrifier denitrification and denitrification. We evaluated a set of scenarios on the presence of such exchange using data from a series of 18O and 15N tracing experiments. The measured actual O incorporation from H2O into N2O (AOI) was compared with the theoretical maximum O incorporation (MOI) from various scenarios that differed in their assumptions on the presence of O exchange. We found that scenarios where O exchange was assumed to occur exclusively during denitrification could not explain the observed AOI, as it exceeded the MOI for 9 out of 10 soils. This demonstrates that additional O exchange must have occurred in N2O production through nitrifier pathways. It remains to be determined in which steps of these pathways O exchange can take place. We conclude that O exchange is likely to be mediated by ammonia oxidizers during NO2− reduction (nitrifier denitrification), and that it could possibly occur during NO2− oxidation to NO3− by nitrite oxidizers as well. 相似文献
188.
In rural areas, representing about 97% of the agricultural and horticultural area, the content of heavy metals in harvested products does not create a significant risk to consumers. In urban areas with about 3% of the horticultural area and on agricultural production fields with corresponding history, local contaminations may exceed the precautionary values for soils. For these areas, an estimation of possible risks is advisable and necessary. On the base of investigations of transfer of heavy metals (As, Cd, Cr, Co, Cu, Hg, Ni, Pb as well as Zn) via the path soil to plant “bio concentration factors” (BCF) have been determined for various horticultural crops (leaf-vegetable, shoot-vegetable, fruit-vegetable, root-vegetable, kitchen herbs and fruit). By use of these BCFs in combination with human toxicological values of the heavy metals (TDI), guiding values can be derived for tolerable soil contamination with the respective metals. These guiding values allow a simple risk assessment of the respective contaminated soils for cultivation and consumption of crops or crop products. 相似文献
189.
190.