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排序方式: 共有79条查询结果,搜索用时 15 毫秒
1.
Suomela JP Ahotupa M Yang B Vasankari T Kallio H 《Journal of agricultural and food chemistry》2006,54(19):7364-7369
Sea buckthorn (Hippopha? rhamnoides L.) is a rich source of flavonols, especially isorhamnetin. Most prospective cohort studies have indicated some degree of inverse association between flavonoid intake and coronary heart disease. Animal and human studies suggest that sea buckthorn flavonoids may scavenge free radicals, lower blood viscosity, and enhance cardiac function. The effects of flavonol aglycones derived from sea buckthorn on the risk factors of cardiovascular disease as well as their absorption were studied in humans. The flavonols, ingested with oatmeal porridge, did not have a significant effect on the levels of oxidized low-density lipoprotein, C-reactive protein, and homocysteine, on the plasma antioxidant potential, or on the paraoxonase activity. Flavonols at two dosages in oatmeal porridge were rapidly absorbed, and a relatively small amount of sea buckthorn oil added to the porridge seemed to have increased the bioavailability of sea buckthorn flavonols consumed at the higher dose. 相似文献
2.
One of the first steps in estimating the potential for reducing emissions from deforestation and forest degradation (REDD) initiatives is the proper estimation of the carbon components. There are still considerable uncertainties about carbon stocks in tropical rain forest, coming essentially from poor knowledge of the quantity and spatial distribution of forest biomass at the landscape level. 相似文献
3.
This paper examines the first-best instruments for biodiversity maintenance in commercial boreal forests when landowners behave either in Faustmannian or Hartmanian way. Using an extended Hartman model, we show that biodiversity conservation requires both prolonged rotation age and leaving retention trees. While the former promotes some old growth species, the latter create new structural elements of decaying and dead wood, which can sustain a variety of saprolyxic species. A fully synchronized combination of retention tree subsidy and tax instrument is needed both to lengthen the privately optimal rotation period and to provide an incentive to leave retention trees. Using Finnish data we illustrate empirically the sizes of instruments. When combined with a harvest tax, the retention tree subsidy is 1000 and 750 € in the Faustmann and in the Hartman model, respectively. When used with a timber subsidy or a site value tax, the retention tree subsidy is 1700 €/ha in both models. The harvest tax rate varies over the range 40–65% in the Faustmann model and 20–40% in the Hartman model, while timber subsidy is between 0.5–1.0% and site value tax is about 1.75%. 相似文献
4.
Non-destructive measurement techniques were used to study the characteristics of thermally modified timber (TMT), especially checking. Two non-destructive measurement techniques were evaluated: air-coupled ultrasound (ACU) and electrical impedance spectroscopy (EIS). In the studied TMT (N = 38), density and pith location in the cross-section were positively correlated with the number of checks in the cross-section. Several ultrasound signal features correlated with TMT characteristics, most strongly with number of checks. Severely checked samples and other samples were considered as two different classes of checking, and the potential of ultrasound for differentiating between the two classes was tested by using Bayesian classification method. The correct classification rate was 97 %. EIS parameters correlated with density and latewood content of TMT more strongly than the ACU parameters. Thus, for determination of checking and density or earlywood/latewood content, both EIS and ACU measurements are recommended. 相似文献
5.
A numerical model was developed for the bioaccumulation of mercury (Hg) in fish. The model is based on the bioenergetic calculation of fish growth, food consumption, respiration, specific dynamic action and waste losses (egestion/excretion) using the program of Hewett and Johnson (1992). Based on the predation and food results obtained, the accumulation of Hg in fish is calculated taking into account the concentrations of methyl mercury (MeHg) in food and water, its intake and accumulation from food and from water, and the removal of Hg from the body. Some species at various levels of food web are considered in the multistep model applications. The model is used to compute the changes of Hg contents in perch (as prey) and pike (as predator) caused by the release of Hg from the bottom sediments when the Kokemäki River in Western Finland was dredged. The model results were not far from the observed results even though the forcing conditions had been described only roughly. 相似文献
6.
7.
Kobayashi H Pohjanvirta T Pelkonen S 《The Journal of veterinary medical science / the Japanese Society of Veterinary Science》2002,64(11):1071-1073
The role of birds as sources of Shiga toxin-and intimin-producing Escherichia coli was studied. Fecal samples from live gulls (n=86), pigeons (n=33) and broiler chickens (n=199) from 23 flocks were analyzed for stx and eae by PCR. No stx positive samples were detected. In contrast, eae E. coli were highly prevalent among gulls (40%), and was also found in pigeons (7%) and chickens (57% of the flocks contaminated). The eae positive isolates were analyzed genetically and O-serogrouped. One isolate from a pigeon was found to have stx (2f). The isolates of gulls differed from those of pigeons and chickens, and all eae E. coli isolates from birds differed from human pathogenic strains by the lack of EHEC-hlyA and bfp/EAF as well as distribution of O-serogroups. Thus, birds cannot be regarded as important carriers of zoonotic stx or eae E. coli in Finland. 相似文献
8.
Enset (Ensete ventricosum), commonly known as false banana, is a large thick, single-stemmed, perennial herbaceous banana-like plant growing in the wild of sub-Sahara Africa, Madagascar and parts of Asia. In Ethiopia it has been domesticated and serves as a food plant. While the productivity and management of enset for food (pseudostem and corm) has been studied, little attention has been given to total biomass production and associated carbon sequestration. The objective of this study was to develop and evaluate allometric models for estimating above and belowground biomass and organic matter contents of enset grown in indigenous agroforestry systems in Rift Valley escarpment of south-eastern Ethiopia. Biomass harvesting of 40 plants was carried out at altitudes from 1900 to 2400 m.a.s.l. The mean plant dry weight was 9.4 ± 0.84 kg and organic matter content 94 %. Pseudostem biomass accounted for highest (64 %) of total biomass, followed by corm (24 %) and foliage (12 %). Basal diameter (d 10) was the best predictor variable for total and all biomass components (Spearman r = 0.775–0.980, p < 0.01). The power model using d 10 and height (H) (Y = 0.0007d 10 2.571 H 0.101; R 2 = 0.91) was found to be the best performing model (highest ranking over six good-of-fit statistics) for predicting total biomass. Model performance decreased in the order pseudostem > corm > foliage biomass. The models presented can be used to accurately predict biomass and organic matter of enset in the agroforestry systems of Rift Valley escarpments Ethiopia. 相似文献
9.
Suvi P. Pietarinen Stefan M. Willför Markku O. Ahotupa Jarl E. Hemming Bjarne R. Holmbom 《Journal of Wood Science》2006,52(5):436-444
The antioxidant properties of hydrophilic extracts of knotwood of several industrially important tree species were evaluated
by lipid-peroxidation inhibition and peroxyl-trapping capacity tests. The results were compared with the antioxidant properties
of hydrophilic extracts of bark, and pure lignans and flavonoids isolated from knotwood extracts. The knot extracts from several
tree species were stronger antioxidants than the bark extracts, which can, however, also be classified as strong antioxidants.
In addition, the antioxidant properties of most of the knotwood extracts are stronger than the pure compounds. It is concluded
that knotwood is a rich source of natural antioxidants. 相似文献
10.
Ken Steen Pedersen Markku Johansen ?ystein Angen Sven Erik Jorsal Jens Peter Nielsen Tim K Jensen Roberto Guedes Marie St?hl Poul B?kbo 《Irish veterinary journal》2014,67(1)