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排序方式: 共有568条查询结果,搜索用时 7 毫秒
1.
Totally 13575 ewes of two different breeds, Dala and Spel, were inseminated with semen, frozen in straws and thawed at 70°C for 8 sec. An insemination dose of 0.2 ml containing approx. 150 × 106 spermatozoa with at least 45 to 50% progressive motility was imerted 5 to 12 mm into the cervix. The insemination was performed once between 12 and 30 h after the onset of heat. The NR rate of the Dala ewes increased significantly during the season. The NR rate of the ewes inseminated before 15. November was 44.3%, from 15. to 20. November 52.2%. from 20. to 25. November 55.3% and from 25. November and later 61.4%. The corresponding values for the ewes of the Spel breed were 57.3, 58.7, 61.5 and 71.0% respectively, and only the difference between the two last values was statistically significant. The difference between the fertility of the two breeds was significant within each of the periods . 相似文献
2.
A A Andersen 《American journal of veterinary research》1978,39(4):603-606
Serum samples were obtained from 30 Hereford steers in an area known to be free of foot-and-mouth disease (FMD) viruses as follows: before shipment and 4 times during a 70-day period after shipment; the sera were tested for the presence of cross-reacting antibody to various viruses. Percentages of sera containing cross-reacting antibody to FMD virus detected by the plaque-reduction neutralization and the radial immunodiffusion techniques were higher for the FMD viruses Asia and SAT I5 than for the FMD viruses A5, O1, and C1. Cross-reacting antibody was usually of low titer and usually present in only 1 or 2 consecutive serum samples. The incidence of cross reactions increased after stress of shipping and thus an infective agent may be responsible. These results were compared with results from sera collected from Herefords and Holstein-Friesians in a 2nd area; results did not indicate that Herefords have an excess of cross reactions with FMD viruses. 相似文献
3.
Potential antioxidants in beer assessed by ESR spin trapping 总被引:5,自引:0,他引:5
A number of potential antioxidants have been evaluated for their effect on formation of radicals in beer using the electron spin resonance (ESR) lag phase method. Sulfite was found to be the only compound that was able to delay the formation of radicals, whereas phenolic compounds such as phenolic acids, catechin, epicatechin, and proanthocyanidin dimers had no effect on the formation of radicals. Ascorbate, cystein, and cysteamin were on the other hand found to be prooxidants. It is suggested that antioxidants must be able to either scavenge peroxides or trap metal ions in order to be effective in beer. The effectiveness of sulfite is suggested to be a consequence of its two-electron nonradical producing reaction with peroxides. 相似文献
4.
Bergadano A Andersen OK Arendt-Nielsen L Theurillat R Thormann W Spadavecchia C 《Veterinary journal (London, England : 1997)》2009,182(2):252-260
This study quantitatively investigated the analgesic action of a low-dose constant-rate-infusion (CRI) of racemic ketamine (as a 0.5 mg kg−1 bolus and at a dose rate of 10 μg kg−1 min−1) in conscious dogs using a nociceptive withdrawal reflex (NWR) and with enantioselective measurement of plasma levels of ketamine and norketamine. Withdrawal reflexes evoked by transcutaneous single and repeated electrical stimulation (10 pulses, 5 Hz) of the digital plantar nerve were recorded from the biceps femoris muscle using surface electromyography.Ketamine did not affect NWR thresholds or the recruitment curves after a single nociceptive stimulation. Temporal summation (as evaluated by repeated stimuli) and the evoked behavioural response scores were however reduced compared to baseline demonstrating the antinociceptive activity of ketamine correlated with the peak plasma concentrations. Thereafter the plasma levels at pseudo-steady-state did not modulate temporal summation. Based on these experimental findings low-dose ketamine CRI cannot be recommended for use as a sole analgesic in the dog. 相似文献
5.
TH Tølbøll AM Danscher PH Andersen MC Codrea E Bendixen 《Veterinary journal (London, England : 1997)》2012,193(3):694-700
Claw horn disruption (CHD) is a common underlying cause of lameness in dairy cattle which leads to compromised animal welfare and production losses. Despite an intense research effort over the last two decades, progress in reducing the prevalence of lameness due to CHD has been limited. In addition to current research strategies there is a need to develop novel approaches and methods that expand understanding of the disease mechanisms involved in CHD. The objectives of the present study were to explore the potential of liquid chromatography tandem mass spectrometry (LC-MS/MS) in mapping protein expression in three different bovine claw tissues, and to provide a relevant functional annotation of the proteins characterized in these tissues. LC-MS/MS was used to characterize protein expression in coronary band skin (C), claw dermal (D) and lamellar (L) tissues from two heifers. A total of 388 different proteins were identified, with 146 proteins available for identification in C, 279 proteins in D and 269 proteins in L. A functional annotation of the identified proteins was obtained using the on-line Blast2GO tool. Three hundred and sixteen of the identified proteins could be subsequently grouped manually to one or more of five major functional groups related to metabolism, cell structure, immunity, apoptosis and angiogenesis. These were chosen to represent basic cell functions and biological processes potentially involved in the pathogenesis of CHD. The LC-MS/MS-based proteomic analysis presented here is the largest published survey, so far, of the bovine claw tissue proteome. 相似文献
6.
Development and application of functional markers in maize 总被引:8,自引:0,他引:8
Thomas Lübberstedt Imad Zein Jeppe Reitan Andersen Gerhard Wenzel Birte Krützfeldt Joachim Eder Milena Ouzunova Shi Chun 《Euphytica》2005,146(1-2):101-108
Summary Functional markers (FMs) are derived from polymorphic sites within genes causally involved in phenotypic trait variation (Andersen,
J.R. & T. Lübberstedt, 2003. Trends Plant Sci 8: 554–560). FM development requires allele sequences of functionally characterized
genes from which polymorphic, functional motifs affecting plant phenotype can be identified. In maize and other species with
low levels of linkage disequilibrium, association studies have the potential to identify sequence motifs, such as a few nucleotides
or insertions/deletions, affecting trait expression. In one of the pioneering studies, nine sequence motifs in the dwarf8 gene of maize were shown to be associated with variation for flowering time (Thornsberry, J.M., M.M. Goodman, J. Doebley,
S. Kresovich, D. Nielsen & E.S. Buckler, 2001. Nat Genet 28: 286–289). Proof of sequence motif function can be obtained by
comparing isogenic genotypes differing in single sequence motifs. At current, the most appropriate approach for this purpose
in crops is targeting induced local lesions in genomes (TILLING) (McCallum, C.M., L. Comai, E.A. Greene & S. Henikoff, 2000.
Nat Biotechnol 18: 455–457). In central Europe, maize is mainly grown as forage crop, with forage quality as major trait,
which can be determined as proportion of digestible neutral detergent fiber (DNDF). Brown midrib gene knock out mutations have been shown to be beneficial for forage quality but disadvantageous for overall agronomic performance.
Two brown midrib genes (bm1 and bm3) have been shown to be involved in monolignol biosynthesis. These two and additional lignin biosynthesis genes have been
isolated based on sequence homology. Additional candidate genes putatively affecting forage quality have been identified by
expression profiling using, e.g., isogenic bm lines. Furthermore, we identified an association between a polymorphism at the COMT locus and DNDF in a collection of European
elite inbred lines. 相似文献
7.
Christian?P.?Andersen Ivan?Nikolov Petia?Nikolova Rainer?Matyssek Karl-Heinz?H?berleEmail author 《European Journal of Forest Research》2005,124(3):155-163
Seasonal fluxes of CO2 from soil and the contribution of autotrophic (root + mycorrhizal) to total soil respiration (SR) were estimated for a mixed
stand of European beech (Fagus sylvatica) and Norway spruce (Picea abies) in Central Europe. Mature trees of each species were girdled in August 2002 to eliminate carbohydrate allocation to roots.
SR was measured at distances of 0.5, 1.0, and 1.5/2.0 m from the bole of each tree at 1–2 weeks intervals throughout the fall
of 2002 and monthly during the spring and summer of 2003. The contribution of roots and mycorrhizae to total SR was estimated
by the decrease in SR compared to ungirdled control trees to account for seasonal patterns evident in controls. SR decreased
with soil temperature in the fall 2002 and increased again in 2003 as soil warmed. During most of the study period, SR was
strongly related to soil temperature. During the dry summer of 2003, however, SR appeared to be uncoupled from temperature
and was strongly related to soil water content (SWC). Mean rates of SR in beech and spruce control plots as well as root densities
did not show a clear pattern with distance from the bole. SR decreased to levels below controls in beech within a few days
after girdling, whereas spruce did not show a significant decrease until October 2002, 6 weeks after girdling. In both beech
and spruce, decreased SR in response to girdling was greatest closest to the bole, possibly reflecting increased mycorrhizal
activity close to the bole. Autotrophic respiration was estimated in beech to be as much as 50% of the total SR in the stand.
The contribution of autotrophic respiration was less certain for spruce, although close to the bole, the autotrophic fraction
may contribute to total SR as much as in beech. The large fraction of autotrophic respiration in total SR requires better
understanding of tree level stresses that affect carbon allocation below ground. 相似文献
8.
Changes in phosphorus fractions in three tropical soils amended with corn cob and rice husk biochars
Joseph Osafo Eduah Mark Kofi Abekoe Mathias Neumann Andersen 《Communications in Soil Science and Plant Analysis》2020,51(10):1331-1340
ABSTRACT The formation of phosphorus (P) compounds including iron-P, aluminum-P and calcium-P in highly weathered tropical soils can be altered upon biochar addition. We investigated the effect of corn cob biochar (CC) and rice husk biochar (RH) pyrolyzed at three temperatures (300°C, 450°C and 650°C) on phosphorus (P) fractions of three contrasting soils. A 90d incubation study was conducted by mixing biochar with soil at a rate of 1% w/w and at 70% field capacity. Sequential P fraction was performed on biochar, soil and soil-biochar mixtures. Increase in most labile P (resin-Pi, NaHCO3-Pi) and organic P fraction (NaHCO3-Po + NaOH-Po) in CC and RH biochars were inversely related to increasing temperature. HCl-Pi and residual P increased with increasing temperature. Interaction of CC and RH with soils resulted in an increase in most labile P as well as moderately labile P (NaOH-Pi) fractions in the soils. CC increased most labile P in the soils more than RH. The increase in most labile P fraction in soils was more significant at relatively lower temperatures (300°C and 450°C) than 650°C. However, the increase in HCl-Pi and residual P of the soils was more predominant at high temperature (650°C). The study suggested that biochar pyrolyzed at 300–450°C could be used to increase P bioavailability in tropical soils. 相似文献
9.
K. Th. Andersen 《Journal of pest science》1937,13(7):81-84
Ohne Zusammenfassung
Mit 5 Abbildungen. 相似文献
10.
Reidar Vestad 《Euphytica》1960,9(1):35-38
In infection experiments with clover rot (Sclerotinia trifoliorum
Erikss.) on 9 pairs of diploid and corresponding autotetraploid families arisen from chimaera plants the tetraploid families proved to be more resistant than their corresponding diploid families. Significant interaction between family pairs and ploidy level was demonstrated and this is an indication that there may be differences between different genotypes with respect to the effect of autotetraploidy on resistance to clover rot in red clover.
Samenvatting Bij kunstmatige infectie met klaverkanker van 9 paren (uit chimaere planten van rode klaver afkomstige) diploide en daarmede corresponderende autotetraploide families bleken de tetraploide families grotere resistentie te vertonen dan de daarmede corresponderende diploide families.Uit een vergelijking van de families bleek dat er verschillen in invloed van de autotetraploidie op de resistentie tegen klaverkanker zijn.相似文献