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71.
A two-tiered approach to long-range climate forecasting 总被引:1,自引:0,他引:1
Bengtsson L Schlese U Roeckner E Latif M Barnett TP Graham N 《Science (New York, N.Y.)》1993,261(5124):1026-1029
Long-range global climate forecasts were made by use of a model for predicting a tropical Pacific sea-surface temperature (SST) in tandem with an atmospheric general circulation model. The SST is predicted first at long lead times into the future. These ocean forecasts are then used to force the atmospheric model and so produce climate forecasts at lead times of the SST forecasts. Prediction of seven large climatic events of the 1970s to 1990s by this technique are in good agreement with observations over many regions of the globe. 相似文献
72.
Regulation of carcinogen metabolism in the rat ovary by the estrous cycle and gonadotropin 总被引:1,自引:0,他引:1
The activity of 7,12-dimethylbenz[a]anthracene hydroxylase in the rat ovary is several times higher in the proestrous phase of the estrous cycle than in the estrous and metestrous plus diestrous phases. Administration of gonadotropin leads to a similar increase in the capacity of the ovary to metabolize xenobiotics. This variation in the activity of 7,12-dimethylbenz[a]anthracene hydroxylase during the estrous cycle may be related to the marked changes in the incidence of ovarian cancer during menopause and in women taking contraceptive pills. 相似文献
73.
Curtis MA Kam M Nannmark U Anderson MF Axell MZ Wikkelso C Holtås S van Roon-Mom WM Björk-Eriksson T Nordborg C Frisén J Dragunow M Faull RL Eriksson PS 《Science (New York, N.Y.)》2007,315(5816):1243-1249
The rostral migratory stream (RMS) is the main pathway by which newly born subventricular zone cells reach the olfactory bulb (OB) in rodents. However, the RMS in the adult human brain has been elusive. We demonstrate the presence of a human RMS, which is unexpectedly organized around a lateral ventricular extension reaching the OB, and illustrate the neuroblasts in it. The RMS ensheathing the lateral olfactory ventricular extension, as seen by magnetic resonance imaging, cell-specific markers, and electron microscopy, contains progenitor cells with migratory characteristics and cells that incorporate 5-bromo-2'-deoxyuridine and become mature neurons in the OB. 相似文献
74.
75.
Heidi Moe Tim Dempster Leif Magne Sunde Ulf Winther & Arne Fredheim 《Aquaculture Research》2007,38(1):91-99
Escapes of cod (Gadus morhua) from sea cages represent an economic problem for farmers and a potential environmental problem. We estimate that 0–6% of cod held in sea‐cage farms in Norway were reported to have escaped each year from 2000 to 2005, which is a high proportion compared with salmon. We interviewed employees at 19 coastal sea‐cage cod farms in Norway to investigate both how and why cultured cod escape and to document cage handling and management strategies that were effective in minimizing escapes. Based on the interviews, we describe five working hypotheses that may explain why a greater proportion of cod than salmon escape: (1) cod are more willing to escape than salmon; (2) cod bite the net cage and create wear and tear; (3) net cages have insufficient technical standards for cod culture; (4) cod are placed in sea cages at considerably smaller sizes than salmon; and (5) cod are more popular feed for predators. Preliminary testing of the hypothesis that cod bite netting and create holes was done by placing pre‐damaged net panels with cut twines and control panels inside sea cages. Holes in the pre‐damaged net panels increased in size over a period of 3 months. The type of damage indicated that biting of netting twines was the likely cause. 相似文献
76.
Ehn BM Ekstrand B Bengtsson U Ahlstedt S 《Journal of agricultural and food chemistry》2004,52(5):1398-1403
The effect of heat treatment on the IgE binding ability of beta-lactoglobulin, as pure protein or in whole milk, was studied by inhibition of IgE antibody binding using FEIA-CAP inhibition. A slight but significant decreased IgE binding was seen between unheated and heat-treated beta-lactoglobulin solution at 74 degrees C (IC(50) = 2.03 and 3.59 microg/mL, respectively, p = 0.032). A more pronounced decrease was found at 90 degrees C with an IC(50) of 8.45 microg/mL (p = 0.014). The inhibition of IgE binding of milk after heat treatment at 90 degrees C was also significantly decreased (p = 0.007). However, at all heat treatments, a similar total amount of IgE antibodies could be inhibited at a sufficiently high concentration of beta-lactoglobulin. The inhibiting ability of beta-lactoglobulin was significantly impaired in some fermented acidified milk products such as yogurt as compared to that in nonfermented milk (p < 0.001). There was only a small difference of IgE binding between the native forms of genetic variants A and B. 相似文献
77.
Genetic variation in two commercial varieties, ‘Liwally’ and ‘Barok’, and two Swedish natural populations of sheep's fescue, Festuca ovina s.l., was studied by means of starch gel electrophoresis. Variation in allele frequencies was found at the Dial, Gpi2, Got2, Pgdl, Pgm, Tpil and Tpi2 loci. ‘Liwally’, belonging to ssp. vallesiaca, showed clear differences compared to the other samples which belong to ssp. capillata and ssp. vulgaris. Genetic diversity, as measured by per cent polymorphic loci, number of alleles per locus and frequency of heterozygotes, was high in all samples in agreement with what has been found in other perennial, outcrossing mono-cotyledonous species with a wide distribution. The bred varieties and the wild populations did not statistically differ with respect to frequency of heterozygotes or number of alleles, though the last value was lower in the domesticated lines than in the natural populations. No significant deviation from the expected Hardy-Weinberg proportions was found in any of the samples. 相似文献
78.
Møller SM Whittaker AK Stokes JR Gidley MJ Andersen U Bertram HC 《Journal of agricultural and food chemistry》2011,59(18):10097-10103
The molecular motion of water was studied in glucono-δ-lactone-acidified skim milk powder (SMP) solutions with various pH values and dry matter contents. NMR relaxometry measurements revealed that lowering the pH in SMP solutions affected 17O and 1H T2 relaxation rates almost identically. Consequently, the present study indicates that the proteins present in the samples do not affect the 1H relaxation behavior markedly, even at relatively high SMP concentrations (15-25%). Comparison of rheological measurements and NMR measurements suggested that the collapse of κ-casein during acidification could contribute to the initial decrease in 17O and 1H relaxation rate in the pH range between 6.6 and 5.5 for 15% SMP and in the pH range between 6.6 and 5.9 for 25% SMP. However, below pH 5.5 the viscosity and 17O and 1H NMR relaxation rates did not correlate, revealing that the aggregation of casein micelles, which increases viscosity below pH 5.5, does not involve major repartitioning of water. 相似文献
79.
An inexpensive and easily automated flow injection method for determination of urea in cow’s milk was evaluated. Urea is hydrolysed by urease and in a gas diffusion cell the ammonia formed passes a membrane into an indicator solution. The resulting colour change of the indicator is measured at 590 nm.The repeatability of the analysis, expressed as the coefficient of variation (C.V.), was between 0.5 and 1.2%. Measured (y) and expected (x) milk urea concentrations after addition of known amounts of urea were related according to the equation y = 1.00× – 0.12 with a C.V. for the regression of 1.8%. Recommended amounts (0.02 %) of the preservative bronopol (2-bromo-2-nitropropane-1,3-diol) added to the milk did not affect the results (P > 0.05). 相似文献
80.
The acute phase responses to infection and endotoxaemia include reductions in the circulating levels of Fe, Zn and Ca. Most responses are postulated to be mediated by the cytokines interleukin–1 (Il–1) and tumor necrosis factor (TNF) which both are produced by monocytes and macrophages. 相似文献