oalib

OALib Journal期刊

ISSN: 2333-9721

费用:99美元

投稿

时间不限

2017 ( 178 )

2016 ( 343 )

2015 ( 6997 )

2014 ( 8733 )

自定义范围…

匹配条件: “Iliana G. Velcheva” ,找到相关结果约189458条。
列表显示的所有文章,均可免费获取
第1页/共189458条
每页显示
Spatial Distribution and a Retrospective Analysis of the Herpetofauna in the City of Plovdiv, Bulgaria
Ivelin A. Mollov,Iliana G. Velcheva
Ecologia Balkanica , 2010,
Abstract: The current study presents the contemporary status and distribution of theamphibians and reptiles in the city of Plovdiv. To track changes in the status ofamphibians and reptiles in the research area through time, a retrospective analysis wasmade based on available literary data. During the past 100 years four species ofamphibians (Triturus karelinii, Lissotriton vulgaris, Bombina bombina, B. variegata) and fourspecies of reptiles (Coronella austriaca, Zamenis longissimus, Elaphe sauromates, Viperaammodytes) probably have disappeared from the study area; one amphibian species (Bufobufo) and one reptile (Natrix natrix) have not changed their status, one amphibian(Pelobates syriacus) and two reptile species (Ablepharus kitaibelii, Podarcis muralis) havereduced their localities and four amphibian species (Epidalea viridis, Rana dalmatina,Pelophylax ridibundus, Hyla arborea) and seven species of reptiles (Mediodactylus kotschyi,Lacerta trilineata, Lacerta viridis, Podarcis tauricus, Emys orbicularis, Dolichophis caspius,Natrix tessellata) have increased their localities and frequency of occurrence. The recordsof the two tortoise species (Testudo hermanni and T. graeca) in the city, and the presence ofthe Red-eared slider (Trachemys scripta elegans) should be considered as accidental.Important Herpetological Areas (IHA) in the study region are also identified.
A Study on the Processes of Distribution, Accumulation and Transfer of Copper (Cu) in the Organisms of Fishes
Iliana G. Velcheva,Bogdan N. Nikolov
Ecologia Balkanica , 2009,
Abstract: By applying mathematical approaches we studied the distribution of copper in organs and tissues of Alburnus alburnus and Perca fluviatilis from "Topolnitsa” Dam Lake. A deposit of the metal in the kidneys and liver was recorded. We found out that the surveyed species are macroconcentrators of cadmium and zinc and there is a process biomagnification of heavy metals in the trophic levels.
Influence of Zinc on Gill Morphology of Gibelio Carp (Carassius gibelio)
Iliana G. Velcheva,Atanas D. Arnaudov,Elenka S. Georgieva
Ecologia Balkanica , 2010,
Abstract: The influence of increasing concentrations of Zinc sulfate (Zn SO4x7H20) on thehystostructure of Gibelio carp gills was investigated. Changes were observed even in the lowestconcentration (0.1 mg.l-1) – degenerating, cirulation and hyperplastic processes. With the increasingof the Zinc concentration, the hyperplasic processes were predominant over the degenerating andcirulation ones.
Heavy metals content in soil near non1ferous metals production facility and domestic wastes landfill in the area of Kardzhali town
Rositsa E. Chilingirova,Jeni N. Staykova,Iliana G. Velcheva,Vanya M. Naydenova
Ecologia Balkanica , 2011,
Abstract: The predominant soil types in the region of Kardzhali are maroon forest soils highly leached and poorly podzolized. Most of the soils have medium to high erosion ability IIIII degree, and the pH is neutral to slightly alkaline (77,8). Few are weak and moderate acidic pH (6,75). Soils are mostly shallow to moderately deep, poor in nutrients. In the region of Kardzhali main pollutants are heavy metals from miningprocessing and metallurgical business activities of “GorubsoKardzhali” AD and LZC AD, Kardzhali. In the paper are presented results of soil contamination mainly with lead, cadmium, copper and zinc, showing concentrations of lead in the soil over the MAC, according to Ordinance № 3/2008 Standards for acceptable content of harmful substances in soil.
Horse chestnut (Aesculus hippocastanum L.) as a biomonitor of air pollution in the town of Plovdiv (Bulgaria)
SLAVEYA PETROVA,LILYANA YURUKOVA,ILIANA VELCHEVA
Journal of BioScience and Biotechnology , 2012,
Abstract: The present study is a small part of a program for application the methods of passive and active phytomonitoring with herbaceous species, trees, mosses and lichens for assessment of the anthropogenic factor in urban conditions. Aesculus hippocastanum L. was studied as a possible biomonitor of air pollution with heavy metals and toxic elements in the town of Plovdiv (Bulgaria). Concentrations of Cd, Cr, Cu, Pb, V and U in leaf samples from urban areas with different anthropogenic impact were compared. Motor transport was found to be the major source of contaminants. It was found the significant contribution of some factors as urban gradient, canyon-street effect and wind rose in forming the urban air quality.
Eco-physiological Study on the Influence of Contaminated Waters from the Topolnitza River Catchment Area on Some Crops
Iliana Velcheva,Slaveya Petrova,Violeta Dabeva,Diliyan Georgiev
Ecologia Balkanica , 2012,
Abstract: The present study is a small part of a program for an investigation of the water conditions in the Topolnitza Dam Lake, Topolnitza River and its catchment area. The sensitivity of seeds and young wheat, sunflower and mustard plants to heavy metal stress was examined at laboratory conditions. Our results showed that seedling growth was more sensitive to heavy metals in comparison to seed germination. The length of shoot and root has been adversely affected due to water contamination when compared to the control. A certain negative effect on the photosynthetic pigments content was registered.
Effects of the insecticide
STELA STOYANOVA,ELENKA GEORGIEVA,ILIANA VELCHEVA,VESELA YANCHEVA
Journal of BioScience and Biotechnology , 2012,
Abstract: The main goal of the present work is to study the effects of the new neonicotinoid insecticide Actara 25 WG" on the intensity of expression of glycogen in the liver of common carp (Cyprinus carpio L.) by using PAS-reaction on cryosections. Common carp is an economically important fish species, which is widely used as a bioindicator for the health of freshwater basins since it could also survive at very contaminated sites. We have used 6.6 mg/L, 10 mg/L and 20 mg/L of the test chemical under laboratory conditions. The results demonstrated that the intensity of staining of the PAS-reaction is directly proportional to the increasing concentration of the insecticide. In addition, this indicates that the amount of glycogen in hepatocytes also increased. Conglomerates of accumulated glycogen in certain hepatocytes were found at the highest concentration of the insecticide. Therefore, we consider that under the influence of Actara 25 WG" the process of glyconeogenesis in the liver of the studied fish accelerates.
СYTOGENETIC EFFECT OF COMBINED TREATMENT OF LINEAR CORN SEEDS BY MUTAGENES
Velcheva L. G.,Vasin V. A.
Bìologì?nij Vìsnik Melìtopol?s?kogo Der?avnogo Pedagogì?nogo Universitetu ìmenì Bogdana Hmel?nic?kogo , 2011,
Abstract: Study of efficiency of combined processing of corns was done in various succession with putting mutagen.Changes were revealed in actions of direct (chemical mutagen + gamma rays) and indirect (gamma rays + mutagen)successions of combined processing.
Generalized edgewise subdivisions
Katerina Velcheva
Mathematics , 2014,
Abstract: In this paper we classify endofunctors on the simplex category, and we identify those that induce weak equivalence preserving functors on the category of simplicial sets.
Bosquejo histórico sobre las principales teorías de la motivación y su influencia en el proceso de ense?anza-aprendizaje
Batista Silva,Aliocha; Gálvez Espinos,Maydel; Hinojosa Cueto,Iliana;
Revista Cubana de Medicina General Integral , 2010,
Abstract: present study account for a bibliographic review of the motivation area of teaching-educational process and its main objective is to reflect on thus subject. motivation isn't an observable variable but a hypothetical feature deduced from the behavior manifestations and that inference may be correct or incorrect. motivation, together with intelligence and the previous learning, determine if students will achieve the expected academic results or not, or rather, the motivation is means related to other objectives. the student is a active subject of learning, if the learning is revealing, there is a favorable attitude by student and thus a motivation as a unitarian process. one of the more relevant features of motivation is to arrive to a determined and preexisting behavior of student and that behavior be related to its future, in other words, the professor make that student to control its own production and that learning be motivating, process that in its essence is very complex and thus it is necessary to reflect and update the subject in question.
第1页/共189458条
每页显示


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.