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1.
Body condition‐dependent dispersal strategies are common in nature. Although it is obvious that environmental constraints may induce a positive relationship between body condition and dispersal, it is not clear whether positive body conditional dispersal strategies may evolve as a strategy in metapopulations. We have developed an individual‐based simulation model to investigate how body condition–dispersal reaction norms evolve in metapopulations that are characterized by different levels of environmental stochasticity and dispersal mortality. In the model, body condition is related to fecundity and determined either by environmental conditions during juvenile development (adult dispersal) or by those experienced by the mother (natal dispersal). Evolutionarily stable reaction norms strongly depend on metapopulation conditions: positive body condition dependency of dispersal evolved in metapopulation conditions with low levels of dispersal mortality and high levels of environmental stochasticity. Negative body condition‐dependent dispersal evolved in metapopulations with high dispersal mortality and low environmental stochasticity. The latter strategy is responsible for higher dispersal rates under kin competition when dispersal decisions are based on body condition reached at the adult life stage. The evolution of both positive and negative body condition‐dependent dispersal strategies is consequently likely in metapopulations and depends on the prevalent environmental conditions.  相似文献   
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Eight Danish Holstein cows were milked with a 1-mm thick specially designed soft liner on their right rear teat and a standard liner mounted under extra high tension on their left rear teat. Four of the animals were overmilked for 5 min. Rear teats were subjected to ultrasound examination on the first day and to infrared thermography on the second day. Teats were submersed in ethanol 20 min post-milking on the second day. Ultrasonography measurements showed that teat canal length increased by 30–41% during milking. Twenty minutes after milking, teats milked with modified standard liners still had elongated teat canals while teats milked with the soft liner were normalized. Overmilking tended to increase teat wall thickness. Approximately 80% of variability in teat canal length, from before teat preparation to after milking, could be explained by changes during teat preparation. Thermography indicated a general drop in teat temperature during teat preparation. Teat temperature increased during milking and continued to increase until the ethanol challenge induced a significant drop. Temperatures approached pre-challenge rather than pre-milking temperatures within 10 minutes after challenge. Teat temperatures were dependent on type of liner. Mid-teat temperatures post-challenge relative to pre-teat preparation were dependent on overmilking. Thermography and ultrasound were considered useful methods to indirectly and non invasively evaluate teat tissue integrity.  相似文献   
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To find out the infection efficiency of recombinant adeno-as sociated virus 2-mediated exogenou s genes in human peripheral blood monocyte-derived dendritic cells(D Cs),the process of transfection wa s investigated by FITC-labeled rAA V2,and observed under confocal mic roscope.Newly separated dendritic cells were tranfected by rAAV2-luc and rAAV2-GFP at different MOI,and transfection efficiency were detec ted by luminometer for rAAV2-luc a nd flow cytometry for rAAV2-GFP.Th e results were elucidated in four different assay systems:(1)60min w as needed for rAAV2 to bind on den dritic cells,and got into cells in the following 10min;(2)the express ion of luc could be detected at th e MOI as low as 1×10~5v.g/cell,and the expression plateau was reached by the MOI of 10~6~10~7v.g/cell,furt her increase of MOI had no functio n on expression level;(3)transgene expression was detected after 48h, and maintained a higher expression level from 96h to 240h after infec tion;(4)7days postinfection of rAA V2-GFP,5%~18% dendritic cells were GFP positive. These data suggest th at rAAV2 vector can efficiently in fect monocyte-derived dendritic ce lls and mediate exogenous gene exp ression,and that the application o f rAAV2 as vector may be useful fo r gene transfer to dendritic cells in ex vivo immunotherapy.  相似文献   
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A new species of dracunculoid nematode, Moravecia argentinensis n. sp. (Guyanemidae), is described from the blood vessels and body cavity of Brazilian flathead, Percophis brasiliensis Quoy et Gaimard (Perciformes: Percophidae), from off the coast of Argentina. The new species differs from the only other congeneric species, Moravecia australiensis Ribu et Lester, 2004, mainly in the number (14) of cephalic papillae, the length ratio of the muscular and glandular portions of esophagus (1:1-2), more numerous (3-5 pairs) genital papillae in the male, and the presence of a sclerotized copulatory plate. This is the second known species of Moravecia Ribu et Lester, 2004 and the first species of this genus reported from South American waters.  相似文献   
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Cardicola ambrosioi n. sp. (Digenea: Sanguinicolidae) is found in the blood vessels of liver and gills of the Brazilian flathead, Percophis brasiliensis Quoy and Gaimard, 1824 (Pisces: Percophidae), from Mar del Plata, Argentina. Among the 13 known species within Cardicola Short, 1953, the new species closely resembles Cardicola coridodacis Manter, 1954, from which it is distinguished by having a relatively shorter oesophagus, the vitellaria extending anteriorly to the nerve commissure, rather than to the end of anterior caeca, the female pore located closer to male pore, the latter situated medially instead of laterally and by possessing a larger Mehlis gland and a smaller seminal vesicle.  相似文献   
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McNamara, M.E., Orr, P.J., Manzocchi, T., Alcalá, L., Anadón, P. & Peñalver, E. 2011: Biological controls upon the physical taphonomy of exceptionally preserved salamanders from the Miocene of Rubielos de Mora, northeast Spain. Lethaia, Vol. 45, pp. 210–226. The middle Miocene Rubielos de Mora Konservat‐Lagerstätte of northeast Spain is hosted within profundal, finely laminated, lacustrine mudstones. The diverse biota includes abundant salamanders. Most individuals died during separate episodes and sank rapidly postmortem. Specimens are typically preserved in dorso‐ventral aspect, the most hydrodynamically stable orientation. The near‐cylindrical morphology of the body, however, allowed some carcasses to settle in or subsequently re‐orientate into, lateral orientations. Loss of skeletal elements (i.e. reduced completeness) reflects their location within the body and followed a distal to proximal trend. Two stages are identified: initial loss of a small number of phalanges, followed by loss of more proximal limb bones plus additional phalanges. Disarticulation is more complex: it occurred via several mechanisms (notably, abdominal rupture and re‐orientation of part of the body and limbs during decay) and shows no consistent pattern among specimens. The physical taphonomy of the salamanders is controlled predominantly by intrinsic biological factors, i.e. the geometry of the body and of individual skeletal elements, the orientation, inherent strength and location of specific joints and the extent to which soft tissues, particularly the skin, persist during decay. These biological factors probably control patterns of physical taphonomy of other fossil tetrapods with a similar skeletal configuration. □Articulation, completeness, Konservat‐Lagerstätten, orientation, quantitative taphonomy, salamanders.  相似文献   
8.
Bone tissue has an exceptional quality to regenerate to native tissue in response to injury. However, the fracture repair process requires mechanical stability or a viable biological microenvironment or both to ensure successful healing to native tissue. An improved understanding of the molecular and cellular events that occur during bone repair and remodeling has led to the development of biologic agents that can augment the biological microenvironment and enhance bone repair. Orthobiologics, including stem cells, osteoinductive growth factors, osteoconductive matrices, and anabolic agents, are available clinically for accelerating fracture repair and treatment of compromised bone repair situations like delayed unions and nonunions. Preclinical and clinical studies using biologic agents like recombinant bone morphogenetic proteins have demonstrated an efficacy similar or better than that of autologous bone graft in acute fracture healing. A lack of standardized outcome measures for comparison of biologic agents in clinical fracture repair trials, frequent off-label use, and a limited understanding of the biological activity of these agents at the bone repair site have limited their efficacy in clinical applications.  相似文献   
9.
An inhibitor of microRNA-122 reduces viral load in chimpanzees that are chronically infected with hepatitis C virus, suggesting that such an approach might have therapeutic potential in humans.  相似文献   
10.
Microbial‐mediated decomposition of soil organic matter (SOM) ultimately makes a considerable contribution to soil respiration, which is typically the main source of CO2 arising from terrestrial ecosystems. Despite this central role in the decomposition of SOM, few studies have been conducted on how climate change may affect the soil microbial community and, furthermore, on how possible climate‐change induced alterations in the ecology of microbial communities may affect soil CO2 emissions. Here we present the results of a seasonal study on soil microbial community structure, SOM decomposition and its temperature sensitivity in two representative Mediterranean ecosystems where precipitation/throughfall exclusion has taken place during the last 10 years. Bacterial and fungal diversity was estimated using the terminal restriction fragment length polymorphism technique. Our results show that fungal diversity was less sensitive to seasonal changes in moisture, temperature and plant activity than bacterial diversity. On the other hand, fungal communities showed the ability to dynamically adapt throughout the seasons. Fungi also coped better with the 10 years of precipitation/throughfall exclusion compared with bacteria. The high resistance of fungal diversity to changes with respect to bacteria may open the controversy as to whether future ‘drier conditions’ for Mediterranean regions might favor fungal dominated microbial communities. Finally, our results indicate that the fungal community exerted a strong influence over the temporal and spatial variability of SOM decomposition and its sensitivity to temperature. The results, therefore, highlight the important role of fungi in the decomposition of terrestrial SOM, especially under the harsh environmental conditions of Mediterranean ecosystems, for which models predict even drier conditions in the future.  相似文献   
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