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111.
Yujie Ning Xi Wang Xiong Guo Pan Zhang Pengfei Qu Feng Zhang Sen Wang Yanxia Lei Mikko Lammi 《Biological trace element research》2018,183(2):233-244
Overall nutritional status has been proved associated with people’s health. The overall nutritional status of children in Kashin-Beck disease (KBD) areas has been overlooked for decades. Therefore, it is worth investigating in the current generation to gather evidence and make suggestions for improvement. A cross-sectional study with three 24-h dietary recalls was conducted to collect raw data on the daily food intake of children. Recorded food was converted into daily nutrient intakes using CDGSS 3.0 software. WHO AnthroPlus software was used to analyse the BMI-for-age z-score (BAZ) for estimating the overall nutrition status of children. All the comparisons and regression analyses were conducted with SPSS 18.0 software. Multiple nutrient intakes among children from the Se-supplemented KBD-endemic were under the estimated average requirement. The protein-to-carbohydrate ratio (P/C ratio) was significantly higher in children from the non-Se-supplemented KBD-endemic area than the other areas (P < 0.001). The children’s BAZ was negatively associated with age (B = ?0.095, P < 0.001) and the number of KBD relatives (B = ?0.277, P = 0.04), and it was positively associated with better housing conditions, receiving colostrum, and daily intakes of niacin and zinc by multivariate regression analysis (F = 10.337, R = 0.609, P < 0.001).Compared to non-Se-supplemented KBD-endemic area and non-endemic areas, children in Se-supplemented KBD-endemic areas have an insufficient intake of multiple nutrients. School breakfast and lunch programmes are recommended, and strict implementation is the key to ensuring a positive effect. 相似文献
112.
113.
Dead shoots of colonies of a leafy hepatic species, Lophozia silvicola , are replaced by shoots developing from asexual propagules, the gemmae. Observations of two populations of L. silvicola showed a strong decreasing seasonal trend in germinability of the gemmae. We suggest that the non-germinating gemmae enter dormancy, and that the proportion of gemmae entering dormancy is season-specific. We assume that there are two types of gemmae, dormant and non-dormant and that only the dormant gemmae can survive during winter. Using a stochastic individual-based cellular automaton model, we investigated whether selection on season-specific dormancy fraction would lead to a decreasing proportion of germinating gemmae. Thus the germination schedule is the evolving trait in the model. Parameter estimates for the model were based on data collected from a population of L. silvicola in southern Finland over a three-year study period. In the simulations, the germination schedule shaped by evolutionary change was similar to the observed pattern. Thus the modelling results give support to the dormancy hypothesis. The qualitative pattern of decreasing germinability towards the end of the growing season is robust. Quantitative predictions are influenced by changes in parameters; for example, if winter mortality of shoots increases relative to mortality during the growing season, production of an increased fraction of dormant gemmae is favoured, especially at the end of the season. 相似文献
114.
Mikko Peltoniemi Raisa Mäkipää† Jari Liski‡§ Pekka Tamminen 《Global Change Biology》2004,10(12):2078-2091
Forest soils store a substantial amount of carbon, often more than the forest vegetation does. Estimates of the amount of soil carbon, and in particular estimates of changes in these amounts are still inaccurate. Measuring soil carbon is laborious, and measurements taken at a few statistically unrepresentative sites are difficult to scale to larger areas. We combined a simple dynamic model of soil carbon with litter production estimated on the basis of stand parameters, models of tree allometry and biomass turnover rates of different biomass components. This integrated method was used to simulate soil carbon as forest stands develop. The results were compared with measurements of soil carbon from 64 forest sites in southern Finland. Measured carbon stocks in the organic soil layer increased by an average of 4.7±1.4 g m?2 a?1 with increasing stand age and no significant changes were measured in the amount of carbon in mineral soil. Our integrated method indicated that soil carbon stocks declined to a minimum 20 years after clear‐cutting and the subsequent increase in the soil carbon stock (F/H ? 1 m) was 5.8±1.0 g m?2 a?1 averaged over the period to next harvesting (~125 years). Simulated soil carbon accumulation slowed down considerably in stands older than 50 years. The carbon stock measured (F/H ? 1 m) for the study area averaged 6.8±2.5 kg m?2. The simulated carbon stock in soil was 7.0±0.6 kg m?2 on average. These tests of the validity of the integrated model suggest that this method is suitable for estimating the amount of carbon in soil and its changes on regional scales. 相似文献
115.
We studied experimentally how heterospecific attraction may affect habitat selection of migrant passerine birds in Finnish
Lapland. We manipulated the densities of resident tit species (Parus spp.). In four study plots residents were removed before the arrival of the migrants in the first study year, and in four
other plots their densities were increased by releasing caught individuals. In the second year the treatments of the areas
were reversed, allowing paired comparisons within each plot. We also investigated the relative abundance of arthropods in
the study plots by the sweep-net method. This allowed us to estimate the effect of food resources on the abundance of birds.
The heterospecific attraction hypothesis predicts that densities of migrant species (especially habitat generalists) would
be higher during increased resident density. Results supported this prediction. Densities and number of the most abundant
migrant species were significantly higher when resident density was increased than when they were removed. On the species
level the redwing (Turdus iliacus) showed the strongest positive response to the increased abundance of tits. Migrant bird abundances seemed not to vary in
parallel with relative arthropod abundance, with the exception of the pied flycatcher (Ficedula hypoleuca) which showed a strongly positive correlation with many arthropod groups. The results of the experiment indicate that migrants
can use resident tit species as a cue to a profitable breeding patch. The relationship between the abundance of the birds
and arthropods suggests that annual changes in food resources during the breeding season probably do not have a very important
effect on bird populations in these areas. The results stress the importance of positive interspecific interactions in structuring
northern breeding bird communities.
Received: 1 September 1997 / Accepted: 22 January 1998 相似文献
116.
117.
Jirasak?Wong-ekkabutEmail author Mikko?KarttunenEmail author 《Journal of biological physics》2016,42(1):133-146
The alpha-hemolysin (AHL) nanochannel is a non-selective channel that allows for uncontrolled transport of small molecules across membranes leading to cell death. Although it is a bacterial toxin, it has promising applications, ranging from drug delivery systems to nano-sensing devices. This study focuses on the transport of water molecules through an AHL nanochannel using molecular dynamics (MD) simulations. Our results show that AHL can quickly transport water across membranes. The first-passage time approach was used to estimate the diffusion coefficient and the mean exit time. To study the energetics of transport, the potential of mean force (PMF) of a water molecule along the AHL nanochannel was calculated. The results show that the energy barriers of water permeation across a nanopore are always positive along the channel and the values are close to thermal energy (kBT). These findings suggest that the observed quick permeation of water is due to small energy barriers and a hydrophobic inner channel surface resulting in smaller friction. We speculate that these physical mechanisms are important in how AHL causes cell death. 相似文献
118.
Reeve JL Stenson-Cox C O'Doherty A Pörn-Ares I Ares M O'Brien T Samali A 《Biochemical and biophysical research communications》2007,356(3):681-686
Oxidized low density lipoprotein (oxLDL) contributes to the pathophysiology of atherosclerosis, partly by altering gene expression in vascular cells. Here, we show 221 genes differentially regulated by oxLDL in coronary artery smooth muscle cells (CASMC), using oligonucleotide microarrays. These genes were classified into 14 functional groups. A comparable gene expression pattern was detected in apoE(-/-) mice. OxLDL induced an oxidative stress response in CASMC, but not the unfolded protein response. OxLDL also caused CASMC death which was accompanied by increased expression of FasL, Bax, and p53 but was caspase-independent. This approach provides further insight into disease pathology and prognosis. 相似文献
119.
Mikko Mönkkönen 《Biodiversity and Conservation》1999,8(1):85-99
More conservation-oriented forest management practices have been implemented recently in the Nordic countries. The goal of this ecological forest landscape management is to reconcile the commercial harvesting of boreal forests with biodiversity conservation. Management aims at maintaining viable populations of the full array of naturally occurring species in an area while still keeping the timber flow as maximal as possible. Basic ecological tools of managing landscape for biodiversity are (1) to mimic natural disturbance regimes, (2) to set aside areas in permanent or temporary nature reserves, and (3) to enhance dispersal of organisms by creating habitat corridors and stepping stones. The ecological basis of this management system is not well founded, and much more empirical and theoretical research is needed to justify and further develop forest landscape management. It has also proved difficult to assess the economic consequences of more conservation-oriented forest management because the market economy largely fails to give value to forest products other than fibre. Considerable methodological development in the valuation of non-timber goods has occurred in recent years, but there is still much controversy over the justification of the valuation procedure in principle. It seems that both economic and moral approaches to the issue of valuation are inseparable from the choices and decisions we have to make about ecological systems. Perhaps the most fruitful outcome can be achieved by using moral and economic arguments in parallel. 相似文献
120.