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Large-Scale Genetic Structuring of a Widely Distributed Carnivore - The Eurasian Lynx (Lynx lynx)
Eli K. Rueness, Sergei Naidenko, Pl Trosvik, Nils Chr. Stenseth
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0093675
Abstract: Over the last decades the phylogeography and genetic structure of a multitude of species inhabiting Europe and North America have been described. The flora and fauna of the vast landmasses of north-eastern Eurasia are still largely unexplored in this respect. The Eurasian lynx is a large felid that is relatively abundant over much of the Russian sub-continent and the adjoining countries. Analyzing 148 museum specimens collected throughout its range over the last 150 years we have described the large-scale genetic structuring in this highly mobile species. We have investigated the spatial genetic patterns using mitochondrial DNA sequences (D-loop and cytochrome b) and 11 microsatellite loci, and describe three phylogenetic clades and a clear structuring along an east-west gradient. The most likely scenario is that the contemporary Eurasian lynx populations originated in central Asia and that parts of Europe were inhabited by lynx during the Pleistocene. After the Last Glacial Maximum (LGM) range expansions lead to colonization of north-western Siberia and Scandinavia from the Caucasus and north-eastern Siberia from a refugium further east. No evidence of a Berinigan refugium could be detected in our data. We observed restricted gene flow and suggest that future studies of the Eurasian lynx explore to what extent the contemporary population structure may be explained by ecological variables.
Effect of Different Feed Structures and Bedding on the Horizontal Spread of Campylobacter jejuni within Broiler Flocks
Beate Sk?nseng,Birger Svihus,Knut Rudi,Pl Trosvik,Birgitte Moen
Agriculture , 2013, DOI: 10.3390/agriculture3040741
Abstract: In this study, we investigated the effects of different feed structures and beddings on the spread of C. jejuni in broiler flocks, and the effect on the cecal microbiota. Broiler chickens raised in 24 eight-bird group cages on either rubber mat or wood shavings were fed either a wheat-based control diet (Control), a diet where 50% of the ground wheat was replaced by whole wheat prior to pelleting (Wheat), or a wheat-based diet, such as the control diet diluted with 12% oat hulls (Oat). Samples from the cloacal mucosa of all birds were taken daily for C. jejuni quantification and cecum samples were collected at the end of the experiment for C. jejuni quantification and microbiota analyses. We have shown a statistically significant effect of increased feed structure on the reduced spread of C. jejuni in chicken flocks, but no significant differences were detected between types of structure included in the feed. No significant changes in the dominating microbiota in the lower lower gastrointestinal (GI) tract were observed, which indicates that feed structure only has an effect on the upper GI tract. Delaying the spread of C. jejuni in broiler flocks could, at time of slaughter, result in fewer C. jejuni-positive broilers.
Co-Infection Dynamics of a Major Food-Borne Zoonotic Pathogen in Chicken
Beate Sk?nseng,Pl Trosvik,Monika Zimonja,Gro Johnsen,Lotte Bjerrum,Karl Pedersen,Nina Wallin,Knut Rudi
PLOS Pathogens , 2007, DOI: 10.1371/journal.ppat.0030175
Abstract: A major bottleneck in understanding zoonotic pathogens has been the analysis of pathogen co-infection dynamics. We have addressed this challenge using a novel direct sequencing approach for pathogen quantification in mixed infections. The major zoonotic food-borne pathogen Campylobacter jejuni, with an important reservoir in the gastrointestinal (GI) tract of chickens, was used as a model. We investigated the co-colonisation dynamics of seven C. jejuni strains in a chicken GI infection trial. The seven strains were isolated from an epidemiological study showing multiple strain infections at the farm level. We analysed time-series data, following the Campylobacter colonisation, as well as the dominant background flora of chickens. Data were collected from the infection at day 16 until the last sampling point at day 36. Chickens with two different background floras were studied, mature (treated with Broilact, which is a product consisting of bacteria from the intestinal flora of healthy hens) and spontaneous. The two treatments resulted in completely different background floras, yet similar Campylobacter colonisation patterns were detected in both groups. This suggests that it is the chicken host and not the background flora that is important in determining the Campylobacter colonisation pattern. Our results showed that mainly two of the seven C. jejuni strains dominated the Campylobacter flora in the chickens, with a shift of the dominating strain during the infection period. We propose a model in which multiple C. jejuni strains can colonise a single host, with the dominant strains being replaced as a consequence of strain-specific immune responses. This model represents a new understanding of C. jejuni epidemiology, with future implications for the development of novel intervention strategies.
Context-Dependent Competition in a Model Gut Bacterial Community
Eric J. de Muinck, Nils Chr. Stenseth, Daniel Sachse, Jan vander Roost, Kjersti S. R?nningen, Knut Rudi, Pl Trosvik
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0067210
Abstract: Understanding the ecological processes that generate complex community structures may provide insight into the establishment and maintenance of a normal microbial community in the human gastrointestinal tract, yet very little is known about how biotic interactions influence community dynamics in this system. Here, we use natural strains of Escherichia coli and a simplified model microbiota to demonstrate that the colonization process on the strain level can be context dependent, in the sense that the outcome of intra-specific competition may be determined by the composition of the background community. These results are consistent with previous models for competition between organisms where one competitor has adapted to low resource environments whereas the other is optimized for rapid reproduction when resources are abundant. The genomic profiles of E. coli strains representing these differing ecological strategies provide clues for deciphering the genetic underpinnings of niche adaptation within a single species. Our findings extend the role of ecological theory in understanding microbial systems and the conceptual toolbox for describing microbial community dynamics. There are few, if any, concrete examples of context-dependent competition on a single trophic level. However, this phenomenon can have potentially dramatic effects on which bacteria will successfully establish and persist in the gastrointestinal system, and the principle should be equally applicable to other microbial ecosystems.
Study of Decoherence of Elementary Gates Implemented in a Chain of Few Nuclear Spins Quantum Computer Model  [PDF]
G. V. López, P. López
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.31013
Abstract: We study the phenomenon of decoherence during the operation of one qubit transformation, controlled-not (CNOT) and controlled-controlled-not (C2NOT) quantum gates in a quantum computer model formed by a linear chain of three nuclear spins system. We make this study with different type of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of . We also study the behavior of the purity parameter for these gates and different environments and found linear or quadratic decays of this parameter depending on the type of environments.
Study of Decoherence on the Teleportation Algorithm in a Chain of Three Nuclear Spins System  [PDF]
G. V. López, P. López
Journal of Modern Physics (JMP) , 2013, DOI: 10.4236/jmp.2013.41012
Abstract:

We make a numerical study of decoherence on the teleportation algorithm implemented in a linear chain of three nuclear spins system. We study different types of environments, and we determine the associated decoherence time as a function of the dissipative parameter. We found that the dissipation parameter to get a well defined quantum gates (without significant decoherence) must be within the range of γ4×10-4 for not thermalized case, which was determined by using the purity parameter calculated at the end of the algorithm. For the thermalized case the decoherence is stablished for very small dissipation parameter, making almost not possible to implement this algorithm for not zero temperature.

Asplenium nidus; The Bird’s Nest Fern: Developmental Studies and Its Conservation  [PDF]
Ruchi Srivastava, P. L. Uniyal
American Journal of Plant Sciences (AJPS) , 2013, DOI: 10.4236/ajps.2013.45A007
Abstract:

Asplenium nidus L. commonly called as Bird’s Nest Fern, is a threatened, ornamental fern, which is widely used as novel foliage ornamental plant and local people use it in worship. The taxon is threatened due to over exploitation, habitat destruction and genetic barriers. To understand the constraints in the regeneration, reproductive biology studies are made. It is observed that more sporophytes are produced in composite population (13.3%) in comparison to isolate population (10%). This pattern is suggestive of the fact that the parental sporophyte is heterozygous for recessive sporophytic lethal. On the basis of the results obtained A. nidus was initially adapted for outbreeding with the capacity for considerable amount of inbreeding. The low potential of sporophyte production in isolate gametophyte could be the constitution of the zygotic genotype.

DC Electrical Conductivity Studies of GeO2 Doped Lead Vanadate Glass System  [PDF]
P. Tejeswararao, D. L. Sastry
New Journal of Glass and Ceramics (NJGC) , 2017, DOI: 10.4236/njgc.2017.73005
Abstract: Temperature dependent DC electrical conductivity studies of GeO2 substituted lead vanadate glass systems xGeO2(50-x)PbO:50V2O5 (x = 5, 10, 15 mole%) were carried out and the results are reported. X-ray diffraction results reveal that all samples are perfect amorphous in nature. DSC results indicate that the substituent GeO2 is replacing PbO in the glass network in such a way that the eutectic composition is maintained. DC electrical conductivity studies of the glass samples indicate that the systems are characterized by different activation energies in different temperature ranges which in turn depend on the annealing temperature. These results are interpreted in terms of temperature dependent microstructural changes in these glass systems.
The Synthesis of Solvent-Free TiO2 Nanofluids through Surface Modification  [PDF]
P. Y. Yu, Y. P. Zheng, L. Lan
Soft Nanoscience Letters (SNL) , 2011, DOI: 10.4236/snl.2011.12008
Abstract: TiO2 nanoparticles with surface hydroxyl groups are treated by trimethoxysilane (CH3O)3Si(CH2)3O(CH2CH2O)6-9CH3 and a inorganic core/organic shell hybridmaterials, which shows itself a yellow viscous fluid, is obtained. We call it solvent-free TiO2 nanofliuds. Transmission electron microscopy (TEM), Fourier transform infrared spectrum (FTIR), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA) and rheometer are adopted to characterize the product. As a result, the content of TiO2 nanoparticles in the nanofliuds is about 5.5wt%, the functionalized TiO2 nanoparticles possess better dispersion, very low viscosity and an obvious liquid-like behavior at room temperature in absence of solvent.
Biomaterial Based on Doped Calcium Carbonate-Phosphate for Active Osteogenesis  [PDF]
Lyubov F. Koroleva, L. P. Larionov, N. P. Gorbunova
Journal of Biomaterials and Nanobiotechnology (JBNB) , 2012, DOI: 10.4236/jbnb.2012.32028
Abstract: Doped calcium carbonate-phosphate is a biocompatible material that influence actively on the osteogenesis, bone regenerate, strengthening of bone and dental tissues including through the skin. A mechanism of the synthesis reactions of doped nanocrystalline calcium carbonate-phosphate an oscillating type of model for these reactions is proposed. The results indicate that the synthesis involves the formation of hydroxy carbonate complexes from the three calcium carbonate polymorphs (calcite, vaterite, and aragonite) in a solution of ammonium chloride and ammonium carbonate, followed by reaction with orthophosphoric acid. The formation of nanocrystalline calcium carbonate-phosphate doped with Fe2+, Mg2+, Zn2+, K+, Si4+, and Mn2+, has been studied by X-ray diffraction, IR spectroscopy, differential thermal analysis, and energy dispersive X-ray fluorescence analysis. This ensures the preparation of a bioactive material based on octacalcium hydrogen phosphate, and calcium chloride hydroxide phosphates containing cation vacancies. Particle-size analysis data show that the materials contain nanoparticles down to 10 nm in size. Heat treatment of the doped calcium carbonate phosphates produces calcium hydroxyapatite containing cation vacancies, which can be used as a bioactive ceramic.
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