Water availability is a stronger driver of soil microbial processing of organic nitrogen than tree species composition     

Tania L. Maxwell  Laurent Augusto  Ye Tian  Wolfgang Wanek  Nicolas Fanin 《European Journal of Soil Science》2023,74(1):e13350

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The effect of wind on foraging activity of the tenebrionid beetle Lepidochora discoidalis in the sand dunes of the Namib Desert     

Shirley A. Hanrahan  Wolfgang H. Kirchner 《African Zoology》2013,48(4):136-139

The foraging activity of the tenebrionid beetle, Lepidochora discoidalis, was studied in the sand dunes of the Namib Desert. The surface activity of this beetle species was found to be correlated both with time of day and wind speed. Higher numbers were observed on the dune surface between 17:00–19:00 h when wind speeds were consistently higher than 9 m/s. Noise and vibrations in the dune sand were found to be highly dependent on wind speed. Wind blowing at speeds higher than 5 m/s lifts the surface sand grains and generates vibrations in the sand. The peak frequency of these vibrations is in the range of 700–1000 Hz. The vibrational amplitude at the peak frequency is on average 40 dB higher at those wind speeds when the beetles are active compared to lower wind speeds. The results indicate that wind is an important cue for these beetles and can be perceived by buried beetles through substrate vibrations.  相似文献   

Nitrogen retention and plant uptake on a highly weathered central Amazonian Ferralsol amended with compost and charcoal     

Christoph Steiner  Bruno Glaser  Wenceslau Geraldes Teixeira  Johannes Lehmann  Winfried E.H. Blum  Wolfgang Zech 《植物养料与土壤学杂志》2008,171(6):893-899

Leaching losses of N are a major limitation of crop production on permeable soils and under heavy rainfalls as in the humid tropics. We established a field trial in the central Amazon (near Manaus, Brazil) in order to study the influence of charcoal and compost on the retention of N. Fifteen months after organic‐matter admixing (0–0.1 m soil depth), we added ¹⁵N‐labeled (NH₄)₂SO₄ (27.5 kg N ha^–1 at 10 atom% excess). The tracer was measured in top soil (0–0.1 m) and plant samples taken at two successive sorghum (Sorghum bicolor L. Moench) harvests. The N recovery in biomass was significantly higher when the soil contained compost (14.7% of applied N) in comparison to only mineral‐fertilized plots (5.7%) due to significantly higher crop production during the first growth period. After the second harvest, the retention in soil was significantly higher in the charcoal‐amended plots (15.6%) in comparison to only mineral‐fertilized plots (9.7%) due to higher retention in soil. The total N recovery in soil, crop residues, and grains was significantly (p < 0.05) higher on compost (16.5%), charcoal (18.1%), and charcoal‐plus‐compost treatments (17.4%) in comparison to only mineral‐fertilized plots (10.9%). Organic amendments increased the retention of applied fertilizer N. One process in this retention was found to be the recycling of N taken up by the crop. The relevance of immobilization, reduced N leaching, and gaseous losses as well as other potential processes for increasing N retention should be unraveled in future studies.  相似文献   

Periglacial transport distance of Pb derived from small-scale ore veins in the Rhenish Slate Mountains     

Stefan Stückrad  Wolfgang Wilcke 《Geoderma》2008,148(2):232-239

The spatial extent of metal contamination caused by small-scale ore veins is increased by periglacial solifluction. Our objectives were (1) to examine the spatial distribution of Pb in cover beds that migrated over Pb ore veins, (2) to calculate the transport distance of ore-derived Pb, and (3) to determine controls on the transport distance.We examined six transects (320-775 m long) in the Rhenish Slate Mountains in West Germany. The transects included four west-exposed and two east-exposed slopes with inclinations between 2-20°. All transects were forest-covered and located at 280-450 m above sea level. Soils were Dystric Cambisols and Stagnic Luvisols. Samples of 120 B horizons developed in the sediments of the last ice age (Wuerm) were analyzed for total Pb concentrations and partly also ²⁰⁶Pb/²⁰⁷Pb ratios. The Pb concentrations ranged from 20 to 135 mg kg^− 1. The spatial Pb distribution suggested that 14 (out of 18) sampling points showing local Pb concentration maxima contained Pb from ore veins upslope. With a two-end-member-mixing model using ²⁰⁶Pb/²⁰⁷Pb isotope ratios of the ore (²⁰⁶Pb/²⁰⁷Pb ratio: 1.1828) as one end member and of the native substrate (a mixture of slate and loess; ²⁰⁶Pb/²⁰⁷Pb ratio: 1.2254 ± 0.0072) as the other we confirmed that the 14 Pb peaks originated from the ore, because they contained 76-100% of ore-derived Pb. By the use of a geographic information system, the transport distance of this Pb was determined to range between 30 and 110 m. Silt concentrations (Pearson r = − 0.69) and the relief curvature (Cramér's V = 0.60) were major controls on the transport distance. Our study demonstrates that Pb ore veins can increase native soil Pb concentrations in soil derived from the periglacial drift of the last ice age (Wuerm) up to a distance of more than 100 m.  相似文献   

Charcoal and smoke extract stimulate the soil microbial community in a highly weathered xanthic Ferralsol   总被引：2，自引：0，他引：2  

Christoph Steiner  Keshav C. Das  Marcos Garcia  Bernhard Frster  Wolfgang Zech 《Pedobiologia》2008,51(5-6):359-366

The influence of charcoal and smoke condensates (pyroligneous acid, PA) on microbial activity in a highly weathered Amazonian upland soil was assessed via measurements of basal respiration (BR), substrate-induced respiration (SIR), and exponential population increase after substrate addition. PA extracts are commonly used for fertilizer or as pest control in Brazil, where phosphorus (P) availability and nitrogen (N) leaching are among the most severe limitations for agriculture. Microbes play an important role in nutrient cycling and solubilizing of phosphate. BR, microbial biomass, population growth and the microbe's efficiency (expressed by the metabolic quotient) increased linearly and significantly with increasing charcoal concentrations (50, 100 and 150 g kg⁻¹ soil). Application of PA caused a sharp increase in all parameters. We suppose that the condensates from smoke contain easily degradable substances and only small amounts of inhibitory agents, which could be utilized by the microbes for their metabolism.  相似文献   

Spaying-induced coat changes: the role of gonadotropins, GnRH and GnRH treatment on the hair cycle of female dogs   总被引：1，自引：0，他引：1  

Reichler IM  Welle M  Eckrich C  Sattler U  Barth A  Hubler M  Nett-Mettler CS  Jöchle W  Arnold S 《Veterinary dermatology》2008,19(2):77-87

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Demonstration of the articular cartilage of the canine ulnar trochlear notch using high-field magnetic resonance imaging     

Probst A  Modler F  Künzel W  Mlynarik V  Trattnig S 《Veterinary journal (London, England : 1997)》2008,177(1):63-70

The articular cartilage covering the ulnar trochlear notch (UTN) of both elbow joints from 25 adult canine cadavers was demonstrated by the use of high-field magnetic resonance imaging (MRI) with a fat-suppressed, three-dimensional, spoiled gradient echo sequence. The dogs used for this study were divided into five groups: giant, large, mid-sized, small, and chondrodystrophic breeds. The distribution of articular cartilage of the UTN was assessed on MR images. The joints were then opened, and the distribution of the articular cartilage of the UTN was verified. In 29/50 joints, there was good agreement between gross findings of the distribution of the articular cartilage of the UTN and MRI interpretation. Reasons for the poor results in small and chondrodystrophic breeds were decreased thickness of the articular cartilage, small size of the articular surface and of its structural features, and the frequent inability to visualize the joint space.  相似文献   

Effects of a low dose infusion of racemic and S-ketamine on the nociceptive withdrawal reflex in standing ponies     

Peterbauer C  Larenza PM  Knobloch M  Theurillat R  Thormann W  Mevissen M  Spadavecchia C 《Veterinary anaesthesia and analgesia》2008,35(5):414-423

ObjectiveTo investigate the effect of plasma concentrations obtained by a low dose constant rate infusion (CRI) of racemic ketamine or S-ketamine on the nociceptive withdrawal reflex (NWR) in standing ponies.Study designProspective, blinded, cross-over study.AnimalsSix healthy 5-year-old Shetland ponies.MethodsPonies received either 0.6 mg kg⁻¹ racemic ketamine (group RS) or 0.3 mg kg⁻¹ S-ketamine (group S) intravenously (IV), followed by a CRI of 20 μg kg⁻¹minute⁻¹ racemic ketamine (group RS) or 10 μg kg⁻¹minute⁻¹ S-ketamine (group S) for 59 minutes. The NWR was evoked by transcutaneous electrical stimulation of a peripheral nerve before drug administration, 15 and 45 minutes after the start of the bolus injection and 15 minutes after the end of the CRI. Electromyographic responses were recorded and analysed. Arterial blood was collected before stimulation and plasma concentrations of ketamine and norketamine were measured enantioselectively using capillary electrophoresis. Ponies were video recorded and monitored to assess drug effects on behaviour, heart rate (HR), mean arterial blood pressure (MAP) and respiratory rate.ResultsThe NWR was significantly depressed in group RS at plasma concentrations between 20 and 25 ng mL⁻¹ of each enantiomer. In group S, no significant NWR depression could be observed; plasma concentrations of S-ketamine (9–15 ng mL⁻¹) were lower, compared to S-ketamine concentrations in group RS, although this difference was not statistically significant. Minor changes in behaviour, HR and MAP only occurred within the first 5–10 minutes after bolus drug administration in both groups.ConclusionAntinociceptive activity in standing ponies, demonstrated as a depression of the NWR, could only be detected after treatment with racemic ketamine. S-ketamine may have lacked this effect as a result of lower plasma concentrations, a more rapid metabolism or a lower potency of S-ketamine in Equidae so further investigation is necessary.  相似文献   

Cardiopulmonary arrest and resuscitation following an extradural injection in a normovolemic dog     

Martina Mosing Dr med vet  DECVAA  Isabelle K. Iff Dr med vet  DECVAA  Wolfgang Nemetz MD 《Journal of Veterinary Emergency and Critical Care》2008,18(5):532-536

Objective – To describe general anesthesia and successful resuscitation of a dog developing asystole and apnea during extradural injection of local anesthetic and an opioid. Case Summary – A Beagle with a ruptured cranial cruciate was premedicated with acepromazine and methadone. Anesthesia was induced with propofol and, after endotracheal intubation, maintained using isoflurane in oxygen. During extradural injection of a mixture of lidocaine, bupivacaine, and morphine the dog developed apnea and asystole. Cardiopulmonary cerebral resuscitation was started promptly and the dog was successfully resuscitated. New Information Provided – Asystole and apnea are possible serious side effects of extradural anesthesia in dogs. With adequate monitoring and early detection successful resuscitation is possible.  相似文献   

Effect of amino acid deficiency on precaecal amino acid digestibility in broiler chickens     

Wolfgang Siegert  Christian Ganzer  Holger Kluth  Markus Rodehutscord 《Journal of animal physiology and animal nutrition》2019,103(3):723-737

In this study, we determined whether deficient dietary amino acid (AA) concentrations influence the precaecal (pc) AA digestibility when determined using the regression approach. We mixed two basal diets. Basal diet 1 was deficient in essential AAs, whereas adequate AA concentrations were ensured in basal diet 2 by adding free AAs. Rapeseed cake and full‐fat soya beans as test ingredients were included in the basal diets at levels of 100 and 200, and 150 and 300 g/kg, respectively, at the expense of maize starch. Each diet was tested with six replicates of 10 broiler chickens each. The feed intake of the chickens that were fed diets based on basal diet 2 was similar, whereas the feed intake of the chickens that were fed diets based on basal diet 1 differed considerably. The numerical differences in pc AA digestibility determined with basal diet 1 or 2 ranged from 2.6 percentage points to 20.8 percentage points in rapeseed cake and from 0.5 percentage points to 15.2 percentage points in soya beans. Across all measured AAs, the average differences were 10.1 percentage points and 5.4 percentage points in rapeseed cake and soya beans, respectively. The differences in the estimated pc AA digestibility between the basal diets were probably caused by different basal endogenous AA losses in the digesta between treatments as a consequence of different feed intake. Adequate AA concentrations and test ingredient levels that are specifically adjusted to avoid a negative effect on feed intake are recommended for future studies.  相似文献