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2.
Ken Mattsson 《Journal of scientific computing》2003,18(1):133-153
Four different methods of imposing boundary conditions for the linear advection-diffusion equation and a linear hyperbolic system are considered. The methods are analyzed using the energy method and the Laplace transform technique. Numerical calculations are done, considering in particular the case when the initial data and boundary data are inconsistent. 相似文献
3.
K Andersson E Stadberg LA Mattsson G Rybo G Samsioe 《Canadian Metallurgical Quarterly》1996,41(5):476-483
Electrical stimulation of the basal temporal region of the dominant hemisphere before partial temporal lobectomy for epilepsy sometimes produces temporary interruption of language function, but the significance of removal of this area is unknown. We evaluated the correlation between resection of the basal temporal language areas (BTLA) and certain types of postoperative language deficits. In a population of 25 patients, we mapped the inferolateral temporal lobe with cortical electrical stimulation, verifying the positions of the stimulating electrodes with three-dimensional computed tomography (CT). Eighty percent of the patients developed transient language deficits with stimulation, particularly with tests of confrontation naming and comprehension. BTLA was primarily located in the fusiform gyrus, from 1 to 9 cm from the temporal tip. At testing 6-12 months after operation, patients with BTLA resection performed worse (mean 9% decrease) than those with no BTLA resection (mean 4% improvement) on tests of confrontation naming (p = 0.03). Resection size accounted for less of the variance in decrease in confrontation naming than did resection of the BTLA. Tests of performance I.Q. (PIQ), verbal I.Q. (VIQ), or recognition memory for word and verbal learning showed no significant difference between these groups. Most patients do not have language decrease with removal of basal temporal lobe 5-6 cm from the tip, even with removal of BTLA. Some patients, however, have persistent decrease in naming. 相似文献
4.
Transport of phosphorus forms and of nitrate through a clay soil under grass and cereal production 总被引:1,自引:0,他引:1
Many nutrients are lost from soil to water viatile drains. However, there are very few reliable studies of such phosphorus(P)losses under Swedish agriculture practices, especially in connection tofertiliser and slurry applications and related to nutrient balances. Tile drainlosses were measured from nine experimental plots in south-west Sweden; fourplots were measured for 7 years and five plots for 2–3 years. Cereals,mainly spring barley (Hordeum vulgare, L.) and oats(Avena sativa, L.), were grown in six plots, while oneplotwas cultivated with grass, timothy (Phleum pratense L.)andmeadow fescue (Festuca pratensis, L.), one with lucerne(Medicago sativa, L.) and meadow fescue (F.pratensis, L.), and the last one was a set-aside withgrass (Lolium perenne, L. and Trifoliumrepens, L.) that was neither fertilised nor used for crop removal.Attention was paid to the forms in which P was transported to water since thishas important ecological implications. Average losses of particulate P (PP)fromthe set-aside land was significantly lower than from the cerealproduction, but the average losses of soluble reactive P (SRP) and dissolvednonreactive P (DUP) were the same. Average loss of PP from the grass ley during 3years (0.09 kg per ha–1 y–1) wassignificantly less than the losses from cereal production. Total P loss of 0.3kg per ha–1 y–1 was equal to the averagelossfrom the Swedish monitoring network of observation fields. Compared to theaverage nitrate-nitrogen (NO3-N) leaching, which was 7 kg perha–1 y–1 from cereals, the NO3-Nleaching was very low from the plots with lucerne-grass and set-aside.After applying and directly ploughing in 80 kg ha–1 ofsuperphosphate for cereal production in November 1998, 0.6–1.8 kgSRP ha–1 y–1 was lost through the drain tiles.Surface application of cattle slurry in spring 1999 to the grass ley alsoresulted in a very pronounced increased base level of SRP. This paper documentsthe importance of applying slurry during dry conditions and of placingfertiliser into the soil according to crop requirements in the time perspectiveof one year. 相似文献
5.
To successfully manage today’s complex production systems it is essential to study operators’ perception of the system. The paper presents perceived production complexity assessed at seven manufacturing companies with the CompleXity Index (CXI) method. While other methods have measured product variants, layout, work content, tools and information items, CXI combines them into three areas. These three complexity areas (Station design, Work variance and Disturbance handling) help to create an understanding of the complex system by visualising how they contribute to complexity, and show the need to support the operators’ ability to handle the varying work. 相似文献
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In the kraft pulping process, the lignin-containing by-product kraft black liquor is currently combusted as an energy source. LignoBoost is a technique that extracts lignin from kraft black liquor, resulting in a lignin-lean black liquor, which is returned to the process, and an extracted kraft lignin. To facilitate the use of the extracted kraft lignin in high-value applications, it can be refined via fractionation to produce a more homogeneous starting raw material. Hence, the aim of this study is to investigate the behavior of dissolved softwood kraft lignin during cross-flow filtration. The effects of the lignin concentration, pH, and ionic strength on the fractionation of the dissolved lignin during cross-flow filtration are investigated. The results indicate that large amounts of low-molecular-weight kraft lignin can be produced from solutions having a low lignin concentration. Furthermore, the effects of pH and ionic strength on the fractionation of low-molecular-weight lignin are identified within the studied ranges. 相似文献
8.
J. L. Mattsson 《Journal für Verbraucherschutz und Lebensmittelsicherheit》2008,63(4):259-264
In the real world, there is an interaction between pest, plant and pesticide that greatly affects the kinds and amounts of
potentially toxic and allergenic chemicals that we eat. These interactions are virtually ignored in food safety regulation.
Exposure to potentially toxic chemicals from crop foods comes from three principle sources: fungal toxin contamination, natural
toxicants and allergens of the plant itself (‘self-defense’ chemistries), and from synthetic pesticide residues. To be effective,
these ‘self-defense’ chemistries are often potent toxicants. When tested similarly to synthetic pesticides, plant self-defense
chemistries are often toxic to genes, cause cancer, cause reproductive problems, cause birth defects, and the like. Our exposure
to self-defense chemicals and allergenic proteins of plants is variable, and depends on growing conditions, which kind of
crop, which variety of crop, selection for natural resistance to insects and fungi, the plant’s dynamic response to environmental
stressors including insects and fungi, and possible mitigation of insect and fungal stress by use of synthetic or biotechnology
pesticides, and post-harvest management. The ratio of self-defense chemistries to synthetic pesticides in our diets has been
estimated at greater than 10,000 to 1 (Ames, 1983; Beier and Nigg, 2001). Almost the entire focus of society and regulatory
agencies is to manage the 1 part in 10000. Obviously, this partitioning of resources is not scientifically rational. The plant
world is interactive, and this dynamic must be managed to improve food safety. 相似文献
9.
Joaquín M. Azagra-Caro Ignacio Fernández-de-Lucio François Perruchas Pauline Mattsson 《Scientometrics》2009,80(2):441-455
Most studies of patents citations focus on national or international contexts, especially contexts of high absorptive capacity,
and employ examiner citations. We argue that results can vary if we take the region as the context of analysis, especially
if it is a region with low absorptive capacity, and if we study applicant citations and examiner-inserted citations separately.
Using a sample from the Valencian Community (Spain), we conclude that (i) the use of examiner-inserted citations as a proxy
for applicant citations, (ii) the interpretation of non-patent references as indicators of science-industry links, and (iii)
the traditional results for geographical localization are not generalizable to all regions with low absorptive capacity. 相似文献
10.
Coagulation and fibrinolysis are crucial in septic shock and inhibition of thrombin may be beneficial in this circumstance. Since porcine endotoxaemia has been found to replicate severe septic shock, a low molecular weight thrombin inhibitor, melagatran, was infused during the first 3 out of 6 h of endotoxaemia in pigs. Plasma creatinine (p <0.01) and urinary output (p <0.05) were less affected in the melagtran + endotoxin group (n=6) as compared to endotoxaemic controls (n=9). The left ventricular stroke work index, systemic vascular resistance index and oxygen extraction were all less affected (p <0.05) by endotoxin during the infusion of melagatran. The plasma concentration of melagatran declined with an apparent plasma half-life of 5 h as soon as the infusion was stopped. APTT, however, continued to increase after the infusion of melagatran had stopped and reached a maximum of 113 s at 5 h (baseline 17 s). APTT in endotoxaemic control pigs reached a maximum of 22 s. Thus, melagatran may counteract some consequences of endotoxaemia. 相似文献