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131.
132.
Phytoplankton blooms characterize temperate ocean margin zones in spring. We investigated the bacterioplankton response to a diatom bloom in the North Sea and observed a dynamic succession of populations at genus-level resolution. Taxonomically distinct expressions of carbohydrate-active enzymes (transporters; in particular, TonB-dependent transporters) and phosphate acquisition strategies were found, indicating that distinct populations of Bacteroidetes, Gammaproteobacteria, and Alphaproteobacteria are specialized for successive decomposition of algal-derived organic matter. Our results suggest that algal substrate availability provided a series of ecological niches in which specialized populations could bloom. This reveals how planktonic species, despite their seemingly homogeneous habitat, can evade extinction by direct competition.  相似文献   
133.
Flavor of beef has been recognized as an equal quality trait to tenderness and lately high correlations between beef flavor and overall liking of beef have been demonstrated. In this review, we evaluate the effect of breed, sex, age, feeding, growth rate, slaughter method and aging on beef flavor. A common determinator for these factors is their influence on intramuscular fat (IMF) where more IMF increase the overall flavor liking. Feeding can, however, affect the flavor of beef beyond that of the amount of IMF. In several studies, pasture or pasture-based silage lead to a beef flavor characterized as fishy, gamey and grassy in contrast to concentrate-fed beef cattle. A geographical difference in flavor preferences of high-quality beef exists, most clearly illustrated among US consumers who prefer beef from concentrate-fed cattle, whereas European consumers tend to prefer beef from cattle fed a mixed diet on pasture and concentrate.  相似文献   
134.
Historical overfishing and the recent collapse of coastal ecosystems   总被引:9,自引:0,他引:9  
Ecological extinction caused by overfishing precedes all other pervasive human disturbance to coastal ecosystems, including pollution, degradation of water quality, and anthropogenic climate change. Historical abundances of large consumer species were fantastically large in comparison with recent observations. Paleoecological, archaeological, and historical data show that time lags of decades to centuries occurred between the onset of overfishing and consequent changes in ecological communities, because unfished species of similar trophic level assumed the ecological roles of overfished species until they too were overfished or died of epidemic diseases related to overcrowding. Retrospective data not only help to clarify underlying causes and rates of ecological change, but they also demonstrate achievable goals for restoration and management of coastal ecosystems that could not even be contemplated based on the limited perspective of recent observations alone.  相似文献   
135.
136.
To determine potential growth strategies for the German fresh potato market, production area, harvested quantities, producer prices and consumption values for the German potato market were examined using trend analysis. German potato harvests were stable over time due to improved growing techniques. Producer longterm prices stayed stable despite their periodic volatility. Overall production area and levels of fresh potato consumption are undergoing a sharp decline. Furthermore, there is a significant relation between total yield and producer prices as dependent variables. In order to compensate for the reduction in consumption, a framework was developed to change the commodity status of fresh potatoes into a differentiated product with new market potential. A consumer and product orientated market segmentation and analysis was applied to the fresh potato market to identify trends and future opportunities. Application of these new differentiated products will help stop the decline of fresh potato consumption by attracting new customers in urban and rural areas. In addition, these new markets are expected to reduce the producer price volatility.  相似文献   
137.
This study was carried out to evaluate the usefulness of a pre‐maturation step in improving the coordination between cytoplasmic and nuclear maturation of horse compact cumulus oocytes by the addition of roscovitine (ROSC). Oocytes were collected by scraping and pre‐cultured for 18 h in a maturation medium TCM199 supplemented with pyruvate, LH, FSH, insulin growth factor (IGF), epidermal growth factor (EGF), insulin, transferrin and selenium (IVM‐ROSC) or in a simple medium (M199‐ROSC). After pre‐maturation, oocytes from both the groups were in part denuded and fixed‐stained and in part in vitro matured to assess the kinetic of in vitro maturation (IVM). The nuclear progression and the cytoskeletal organization of microfilaments and cortical granules (CG) of treated and untreated oocytes were assessed by fluorescent probes. Oocytes immediately fixed after recovery and oocytes pre‐cultured in M199‐ROSC for 18 h did not show metaphase II (MII) plates, whereas in IVM‐ROSC group, 6/69 oocytes (8.7%) showed MII plates. After inhibition, during maturation kinetics at 11, 18 and 29 h, maturation rate of M199‐ROSC group progressively increased and at 29 h of IVM, reached the maturation rate of control group (13/66, 19.7% vs 31/125, 24.8%). No statistically significant differences in cytoplasmic maturation were found. The number of MII plates after 29 h of IVM, was significantly higher (p < 0.05) in IVM‐ROSC group (34/90) compared with M199‐ROSC (13/66) and control groups (31/125) as well as the number of oocytes with microfilaments and CG distributed in cortical region (25/34 vs 3/13 and 7/31 respectively). Our results showed that pre‐culturing in the presence of Roscovitine in a fully supplemented maturation medium containing gonadotropins and growth factors partially suppressed the meiotic maturation, but established a more suitable environment for improving cytoplasmic maturation of horse compact cumulus oocytes as defined by microfilaments and CG configuration.  相似文献   
138.
139.
Changes in dimensions of impressions of the lumen of the teat canals of 13 cows were examined at 17 intervals during the nonlactating period and early lactation. Impressions were made of teats of 2 diagonally opposed quarters of each cow, using dental impression material. Impression length was measured and cross sections of the impressions at the proximal (distal to Furstenburg rosette), distal (proximal to the teat orifice), and middle (midway between the 2), portions of the teat canal were prepared. Cross sections were photographed and enlarged, and circumference and area were determined by use of planimetry. Effects of making repeated impressions during the nonlactating period and early lactation on new infection rates and somatic cell counts were also assessed. Mean length of teat canal impressions decreased between days 0 and 3 of involution and during the prepartum periods. Depending on the level from which they were taken, cross-sectional areas of impressions tended to increase or increased significantly during the period of involution and again in the prepartum period. Significant changes in cross-sectional area were not observed during early lactation. Changes in circumference of proximal, middle, and distal cross sections followed trends similar to area measurements, but were more variable and differences were less statistically significant. On the basis of our findings, we suggest that heightened susceptibility to new infection during mammary involution and the prepartum period may be attributable, in part, to changes in the patency of the teat canal. Making impressions repeatedly throughout the nonlactating period and early lactation did not affect the number of new intramammary infections.  相似文献   
140.
A 14‐year‐old, female, captive‐born orangutan (Pongo pygmaeus) developed bilateral cataracts. Ultrasonography, electroretinography and cataract correction using phacoemulsification were performed bilaterally. This case report aims to describe the ophthalmic procedures performed in this animal critically endangered of extinction. The surgery successfully restored vision and normal activity to the patient.  相似文献   
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