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1.
Anna Lena Mueller Christian A. Berger Siegfried Schittenhelm Burkhard Stever-Schoo Jens Dauber 《Journal of Agronomy and Crop Science》2020,206(5):529-537
The perennial cup plant (Silphium perfoliatum L.) is considered as an alternative feedstock to maize for biogas plants. Due to its ecological advantages of an extensive management and function as food resource for pollinators, it can be grown in Ecological Focus Areas (EFAs) since 2018. However, studies at the Julius Kühn-Institute in Braunschweig (Germany) showed that the assumed advantage of the cup plant of a high drought tolerance could not be confirmed regarding aspects of crop production and yield. We complemented this experiment by assessing how different soil moisture conditions affect the production of floral resources and insect visitation. In 2014, we sampled three irrigated and three rainfed plots of the cup plant. We quantified the nectar volume and sugar mass per inflorescence, the number of inflorescences per plant and calculated the total nectar sugar production. We further counted insect visitation on the inflorescences. Due to reduced numbers of inflorescences per plant and an earlier harvest, the estimated nectar sugar production was 58 kg/ha regarding irrigated and 20 kg/ha regarding rainfed plots. Honeybee visitation per inflorescence was about twice as high in the irrigated plots. Furthermore, the early harvest is a disadvantage for wild pollinators with a late activity period. 相似文献
2.
Finding suitable growth models for turbot (Scophthalmus maximus L.) in aquaculture 1 (length application) 下载免费PDF全文
Vincent Lugert Jens Tetens Georg Thaller Carsten Schulz Joachim Krieter 《Aquaculture Research》2017,48(1):24-36
Growth data of two different commercial turbot (Scophthalmus maximus) strains reared in recirculating aquaculture systems were analysed with the aim to determine the most suitable model for turbot. To assess the model performance three different criteria were used: (1) The mean percentage deviation between the estimated length and actual length; (2) the residual standard error with corresponding degrees of freedom and (3) the Akaike information criterion. The analyses were carried out for each strain separately, for sexes within strains and for a pooled data set containing both strains and sexes. We tested a pre‐selection of six models, containing three to four parameters. Models were of monomolecular shape or sigmoid shape with a flexible point of inflection including the special case of monomolecular shape in defined cases of their parameters. The 4‐parametric Schnute model achieved best fit in 62% of all cases and criteria tested, followed by the also 4‐parametric generalized Michaelis–Menten equation in 48% and the 4‐parametric Janoschek model (38%). The von Bertalanffy growth function achieved only 29%, Brody 24% and a new flexible function 19% best fit. In a 1–1000 day growth‐simulation sigmoid shaped curves were produced by the Schnute model in 71% of cases. The Janoschek and the Michaelis–Menten model each produced sigmoid curves in 57% of all cases. This indicates that a flexible 4‐parametric function reflects the growth curve of turbot the best and that this curve is rather sigmoid than monomolecular shaped. 相似文献
3.
Jens Botterweck Burkhard Schmidt Jan Schwarzbauer Roschni Kalathoor Andreas Schäffer 《Biology and Fertility of Soils》2014,50(7):1015-1024
We studied the influence of an immobilized laccase from Trametes versicolor on non-extractable residue (NER) formation of the systemic fungicide 14C-metalaxyl in soil. We added the enzyme (130 mU/g DW) to soil sterilized by gamma irradiation and observed that the amount of NER (6.3 % of applied radioactivity) after 10 days of incubation was enhanced about twofold compared to the sterile soil without laccase addition. Residues formed within samples without enhanced enzyme activity were mainly bound via ester linkages to all fractions of humic matter, i.e., fulvic acids, humic acids, non-humines, and humines, respectively. In contrast, residues formed in presence of immobilized laccase were more strongly bound by covalent linkages such as ether and C-C bonds, especially to humic acids. After chemical degradation of the humic matter, it could be observed that all NER contained the first major transformation product, i.e., metalaxyl acid. The findings underline that the residue formation of metalaxyl in soil may be partly catalyzed by immobilized extracellular oxidative enzymes through oxidative coupling reactions within the humic matter. 相似文献
4.
Parallelism in thermal growth response in otoliths and scales of brown trout (Salmo trutta L.) from alpine lakes independent of genetic background 下载免费PDF全文
Low density in natural populations of salmonids has predominantly been managed by stocking of non‐native conspecifics. Due partly to domestication, introduced non‐native fish may be maladapted under natural conditions. Interbreeding between introduced and wild individuals may therefore impair local adaptation and potentially population viability. Brown trout (Salmo trutta L.) from three headwaters (with stocked fish) and three interconnected lakes (with native fish) on the Hardangervidda mountain plateau, southern Norway, were tested for differences in thermal effects on scale and otolith growth. Otolith and scale annuli widths from immature brown trout showed positive correlation with mean annual summer temperature for all six sampled populations. In mature individuals, a similar positive thermal correlation was evident for the otoliths only. Interannuli width measurements from scales indicate a halt in somatic growth for brown trout in this alpine environment when reaching ages between 7 and 9 winters, coinciding with age at maturity. Our study indicates that otolith growth follows summer temperature even when individuals do not respond with somatic growth in these populations and that introduced brown trout and introgressed populations have similar thermal growth responses. Due to the continued otolith growth after stagnation in somatic growth and the impact of fluctuations in summer temperature, the utilisation of otolith annuli widths for back calculation of length at age should be treated with caution. 相似文献
5.
Nonregenerative immune‐mediated anemia associated with a diffuse large B‐cell lymphoma in a captive jaguar (Panthera onca) 下载免费PDF全文
Monika A. Keresztes Manfred Henrich Penelope Baloi Sascha Gerst Jens‐Christian Rudnick Judith Langenstein Andreas Moritz Natali Bauer 《Veterinary clinical pathology / American Society for Veterinary Clinical Pathology》2017,46(4):597-604
An 18‐year‐old male castrated jaguar (Panthera onca) was presented with anorexia and continuous bleeding from the oral cavity after a history of fighting with the partner animal. Clinical evaluation revealed ulcerating lesions on the gingiva and hard palate and a hematoma on the tongue. Computed tomography of the head and endoscopic examination of the esophagus and stomach were unremarkable. Hematology and clinical chemistry revealed severe nonregenerative anemia, mild thrombocytopenia, and moderate azotemia. Several PCRs for feline hemotropic mycoplasmas (Mycoplasma haemofelis, M heamominutium, M turicensis), Babesia felis, and Bartonella spp., as well as an FeLV antigen test were negative. The cytologic examination of a bone marrow aspirate was consistent with ineffective erythropoiesis, most likely due to immune‐mediated destruction of the erythroid precursor cells. Prednisolone therapy was initiated (1.25 mg/kg/day), and the CBC returned to normal 16 days after the initiation of the therapy. Anemia relapsed after 4 months and severe splenomegaly was noted. A repeat bone marrow aspirate revealed active erythropoiesis in the presence of erythroid precursor phagocytosis suggesting an immune‐mediated process. Splenic fine‐needle aspiration and tissue biopsies were taken, and all findings including histology and immunohistochemistry were consistent with a diffuse large B‐cell lymphoma (DLBCL). Five days later, the clinical condition deteriorated and the jaguar died. Histopathology following necropsy showed infiltration with neoplastic lymphoblasts in the spleen, liver, and abdominal lymph nodes. This case report describes a nonregenerative immune‐mediated anemia associated with a DLBCL in a jaguar. 相似文献
6.
Mariko Ingold Gunadhish Khanal Jens Dyckmans Christine Wachendorf Andreas Buerkert 《Communications in Soil Science and Plant Analysis》2018,49(5):537-551
On irrigated agricultural soils from semi-arid and arid regions, ammonia (NH3) volatilization and nitrous oxide (N2O) emission can be a considerable source of N losses. This study was designed to test the capture of 15N loss as NH3 and N2O from previous and recent manure application using a sandy, calcareous soil from Oman amended one or two times with 15N labeled manure to elucidate microbial turnover processes under laboratory conditions. The system allowed to detect 15N enrichments in evolved N2O-N and NH3-N of up to 17% and 9%, respectively, and total N, K2SO4 extractable N and microbial N pools from previous and recent 15N labeled manure applications of up to 7%, 8%, and 15%. One time manured soil had higher cumulative N2O-N emissions (141 µg kg?1) than repeatedly manured soil with 43 µg kg?1 of which only 22% derived from recent manure application indicating a priming effect. 相似文献
7.
Singleton Megan P. Thode Andrea E. Sánchez Meador Andrew J. Iniguez Jose M. Stevens Jens T. 《Landscape Ecology》2021,36(12):3429-3449
Landscape Ecology - Spatial patterns of high-severity wildfire in forests affect vegetation recovery pathways, watershed dynamics, and wildlife habitat across landscapes. Yet, less is known about... 相似文献
8.
Adrian Boswood Sonya G. Gordon Jens Häggström Martin Vanselow Gerhard Wess Rebecca L. Stepien Mark A. Oyama Bruce W. Keene John Bonagura Kristin A. MacDonald Mark Patteson Sarah Smith Philip R. Fox Karen Sanderson Richard Woolley Viktor Szatmári Pierre Menaut Whitney M. Church M. Lynne O'Sullivan Jean-Philippe Jaudon Jan-Gerd Kresken John Rush Kirstie A. Barrett Steven L. Rosenthal Ashley B. Saunders Ingrid Ljungvall Michael Deinert Eric Bomassi Amara H. Estrada Maria J. Fernandez Del Palacio N. Sydney Moise Jonathan A. Abbott Yoko Fujii Alan Spier Michael W. Luethy Roberto A. Santilli Masami Uechi Anna Tidholm Christoph Schummer Philip Watson 《Journal of veterinary internal medicine / American College of Veterinary Internal Medicine》2020,34(3):1108-1118
9.
10.
Katja Albert Peter Annighöfer Jens Schumacher Christian Ammer 《Scandinavian Journal of Forest Research》2014,29(3):210-221
With an increasing demand of sustainable raw materials for bioenergy use, coppicing as management approach to increase the biomass production of forests is becoming of greater importance. This study describes the parameterization of biomass equations for six tree species traditionally used in coppices forests, namely sycamore maple (Acer pseudoplatanus L.), field maple (Acer campestre L.), European ash (Fraxinus excelsior L.), European hornbeam (Carpinus betulus L.), downy birch (Betula pubescens Ehrh.), and common hazel (Corylus avellana L.) growing in coppice-with-standard systems in Lower Saxony, Germany. The parameterization was based on measurements of over 950 trees sampled from two forest sites. The sampled trees were felled and separated into three biomass compartments (stem, coarse branches, and fine brushwood) and weighed on site. The dry weight of sub samples from each compartment was measured. Equations were derived for total aboveground biomass, stem biomass, and crown biomass using regression analyses. We either used diameter at breast height as single independent explanatory variable or in combination with tree height. Biomass production of stump sprouts and generatively grown stems was compared for ash and sycamore maple. In the same age classes, it was found that ash stump sprouts had a slightly higher production than seed-grown stems. For sycamore maple, no difference was detected. 相似文献