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The Static Characteristic Loop and the External Demagnetizing Factor

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Habitat preferences of two sparrow species are modified by abundances of other birds in an urban environment

Materials Sciences and Applications（材料科学与应用期刊） 2012年第10期

作者： j. takacs Gy. Kovacs L. K. Varga

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Current Zoology 2016年第4期62卷 357-368页

作者： Piotr SKoRKA Katarzyna S,ERPOWSKA Andzelika HAIDT Lukasz MYCZKO Anna EKNER-GRZYB Zuzanna M. ROSIN Zbigniew KWlECNsKI j.anna SUCHODOLSKA Viktoria takacs Lukasz j.NKOWIAK Oskar WASIELEWSKI Agnieszka GRACLIK Agata j. KRAWCZYK Adam KASPRZAK Przemystaw SZWAj.OWSKI Przemystaw WYLEGAlA Anna W. MALECHA Tadeusz MIZERA Piotr TRYj.NOWSKI Institute of Nature Conservation Polish Academy of Sciences AI. Mickiewicza 33 31-120 Krakow Institute of Zoology Poznan University of Life Sciences Wojska Polskiego 71 C 66-625 Poznan Department of Forest Ecology Forest Research Institute Braci Lesej Sekocin Stary 05-090 Raszyn Oepartment of Behavioural Ecology Department of Cell Biology Faculty of Biology Adam Mickiewicz University Umultowska 89 61-614 Poznan Zoological Garden Browarna 25 61-063 Poznan Department of Vertebrate Zoology and Anthropology University of Szczecin Wa ska 13 71-412 Szczecin Department of Systematic Zoology Faculty of Biology Adam Mickiewicz University Umultowska 89 61-614 Poznan Division of Rural Tourism Poznad University of Life Sciences Witosa 45/114b 61-693 Poznan Department of Animal Physiology and Biochemistry Poznan University of Life Sciences Wolynska 35 60-637 Poznan Polish Society for Nature Conservation Salamandra Stolarska 7/3 60-788 Poznan Poland

Every species has certain habitat requirements, which may be altered by interactions with other co-occurring species. These interactions are mostly ignored in predictive models trying to identify key habitat variables correlated with species population abundance/occurrence. We investigated how the structure of the urban landscape, food resources, potential competitors, predators, and interaction between these factors influence the abundance of house sparrow Passer domesticus and the tree sparrow P. montanus in sixty 25 ha plots distributed randomly across residential areas of the city of Pozna5 （Poland）. The abundance of the house sparrow was positively correlated with the abundance of pigeons but negatively correlated with human-related food resources. There were significant interaction terms between abundances of other urban species and habitat variables in statistical models. For example, the abundance of house sparrow was negatively correlated with the abundance of corvids and tree sparrows but only when food resources were low. The abundance of tree sparrows positively correlated with density of streets and the distance from the city center. The abundance of this species positively correlated with the abundance of corvids when food resources were low but negatively correlated at low covers of green area. Our study indicates that associations between food resources, habitat covers, and the relative abundance of two sparrow species are altered by the abundance of other urban species. Competition, niche separation and social facilitation may be responsible for these interactive effects. Thus, biotic interactions should be included not only as an additive effect but also as an interaction term between abundance and habitat variables in statistical models predicting species abundance and occu rrence.

关键词： landscape ecology public information spatial autocorrelatien urban ecosystems.

Effect of melatonin on the severity of L-arginine-induced experimental acute pancreatitis in rats

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World j.urnal of Gastroenterology 2006年第2期12卷 251-258页

作者： Annamaria Szabolcs Russel j.Reiter Tamas Letoha Peter Hegyi Gabor Papai Ilona Varga Katalin j.rmay j.zsef Kaszaki Reka Sari Zoltan Rakonczay j. j.nos Lonovics Tamas takacs st Department of Medicine University of SzegedHungary Department of Cellular and Structural Biology University of TexasHealth Science CentreSan AntonioTexasUnited States Institute of Chemistry University of SzegedHungary Biological Research Centre Hungarian Academy of SciencesSzegedHungary Biological Isotope Laboratory University of SzegedHungary Institute of Experimental Surgery University of SzegedHungary

AIM： To determine the effect of melatonin pre- and post-treatment on the severity of L-arginine （L-Arg） -induced experimental pancreatitis in rats. METHODS： Male Wistar rats （25） were divided into five groups. Those in group A received two inj.ctions of 3.2 g/kg body weight L-Arg i.p. at an interval of 1 h. In group MA, the rats were treated with 50 mg/kg body weight melatonin i.p. 30 min prior to L-Arg administration. In group AM, the rats received the same dose of melatonin 1 h after L-Arg was given. In group M, a single dose of melatonin was administered as described previously. In group C the control animals received physiological saline inj.ctions i.p. All rats were exsanguinated 24 h after the second L-Arg inj.ction. RESULTS： L-Arg administration caused severe necrotizing pancreatitis confirmed by the significant elevations in the serum amylase level, the pancreatic weight/body weight ratio （pw/bw）, the pancreatic IL-6 content and the myeloperoxidase activity, relative to the control values. Elevation of the serum amylase level was significantly reduced in rats given melatonin following L-Arg compared to rats inj.cted with L-Arg only. The activities of the pancreatic antioxidant enzymes （Cu/Zn-superoxide dismutase （CulZn-SOD） and catalase （CAT）） were significantly increased 24 h after pancreatitis induction. Melatonin given in advance of L-Arg significantly reduced the pancreatic CAT activity relative to that in the rats treated with L-Arg alone. In the liver, L-Arg significantly increased the lipid peroxidation level, and the glutathione peroxidase and Cu/Zn-SOD activities, whereas the Mn-SOD activity was reduced as compared to the control rats. Melatonin pre-treatment prevented these changes. CONCLUSION： Melatonin is an antioxidant that is able to counteract some of the L-Arg-induced changes during acute pancreatitis, and may therefore be helpful in the supportive therapy of patients with acute necrotizing pancreatitis.

关键词： Acute pancreatitis Melatonin Scavengers

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有限边界对激光弯曲温度场的影响

航空制造技术 2007年第Z1期50卷 429-433页

作者：王秀凤苏余鹏 j.takacs 北京航空航天大学机械工程及自动化学院北京航空航天大学机械工程及自动化学院 Budapest University of Technology and Economics

通过激光点光源辐照板条表面温度场的试验和数值模拟,探讨了激光弯曲成形技术中板条内部热传导的规律,试验表明材料边界与周围环境之间的传热和其对内部材料的热传导对激光辐照下的板条表面温度场的影响显著,并可能导致材料在激光辐照... 详细信息

通过激光点光源辐照板条表面温度场的试验和数值模拟,探讨了激光弯曲成形技术中板条内部热传导的规律,试验表明材料边界与周围环境之间的传热和其对内部材料的热传导对激光辐照下的板条表面温度场的影响显著,并可能导致材料在激光辐照下的热传导规律与经典的傅里叶热传导定律不相符合.通过将试验结果和现有理论的比较,建立了符合实际情况的有限元数值模型,进而分析了激光加工工艺参数对其温度变化的影响.

关键词：有限边界激光弯曲数值模拟