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34352. Variability and differences in the skulls of the common hamster (Cricetus cricetus) from several areas in Central Europe and from different time periods
- Creator:
- Stefen, Clara
- Type:
- article, model:article, and TEXT
- Subject:
- subspecies C.c. canescens, Thuringia, Saxony-Anhalt, Austria, Belgium, the Netherlands, and discriminant analyses
- Language:
- English
- Description:
- The craniometric variability of skulls of the common hamster (Cricetus cricetus) from different countries (Belgium, the Netherlands, Austria, Germany) and different regions within Germany was studied. The aim was to study the variability in different regions and to see if differences between populations exist now and might have existed in former times also. The discriminant analyses were performed for females and males separately. The material was assigned to three different age classes and tests were attempted with all age classes. For the largest sample from Saxony-Anhalt, differences could also be observed between the three selected time periods (1900-1930, 1931-1960 and 1961-1990). Discriminant analyses were performed by keeping the sexes, age classes, and time periods separate wherever the material allowed for it. Regional samples differed to some degree (depending on the set of samples used). Particularly the samples from Austria, Belgium, and the Netherlands were more offset from the German samples; nevertheless, some overlap existed for the males of the third time period. The position of the small sample from the Rhineland was ambiguous in the different discriminant analyses but seemed rather to fall within the range of other German samples and not clearly in-between the German and the Dutch/Belgian samples. Overall variability, changes with time, and possible yearly fluctuations, as described in the literature, influenced the results and overlaid existing regional differences. The existence of a western subspecies could not be supported. The lack of substantial numbers of specimens illustrated the importance of collecting even the common species at all times for future research.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34353. Variability and systematic status of Zonorchis clathratum (Trematoda: Dicrocoeliidae), a parasite of swifts and swallows
- Creator:
- Sitko, J.
- Format:
- Type:
- model:internalpart and TEXT
- Subject:
- Dicrocoeliidae, Zonorchis, and swifts and swallows
- Language:
- English
- Description:
- The morphometrical variability of Zonorchis clalhraium (Deslongschamps, 1824) from Apus apus in the Czech Republic, Z. rutshurensis (Baer, 1959) from Apus cajffer streubeli and Z. dureni Vercammen-Grandjean, 1960 from Hirundo ni-grita in Congo was studied. Zonorchis rulshurensis and Z dureni are considered to be synonyms of Z. clathratum. Lyperosomum oswuldoi Travassos, 1919 sensu Jaroń, 1969 is considered to beZ. clathratum, and L. clathratum (Deslongschamps, 1824) sensu Jaroń, 1969 is considered to be Stromitremu koschewnikovi (Skryabin et Massino, 1925).
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34354. Variability of Mammary Carcinogenesis Induction in Female Sprague-Dawley and Wistar:Han Rats: the Effect of Season and Age
- Creator:
- Kubatka, P., Eva Ahlersová, Ivan Ahlers, Bianka Bojková, Kalická, K., Eva Adámeková, Marková, M., Chamilová, M., and Čermáková, M.
- Format:
- print, bez média, and svazek
- Type:
- article, studie, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, fyziologie člověka, human physiology, Mammary carcinogenesis, Seasons, Critical periods, Rat strains, Susceptibility, 14, and 612
- Language:
- English
- Description:
- It is important to determine and clarify the variability of mammary carcinogenesis induction in animal experimental studies particularly in connection with chemoprevention projects. The circannual seasonal rhythms of hormone levels or various parameters within the immune system may involve factors participating in mammary gland carcinogenesis. In our study, 19 experiments were conducted and all of them lasted for about 25 weeks after chemical carcinogen administration (DMBA or NMU) under standard laboratory conditions. Females of two rat strains - a medium susceptible Sprague-Dawley strain and a very low susceptible Wistar:Han were used. We observed not only the effect of seasonal changes but also the effect of age after single or repeated carcinogen administration. The seasonal dependence of mammary carcinogenesis with higher tumor incidence during long days in comparison with winter short days has been demonstrated in Sprague-Dawley rats. In experiments on the Wistar:Han strain, certain features of seasonal character were recorded, although the very low susceptibility of this strain to mammary carcinogenesis might have influenced the results. A limited period of carcinogen administration in early puberty around postnatal days 43-46 (higher susceptibility), when compared to the period after postnatal day 50, is the factor significantly increasing incidence and frequency of mammary carcinogenesis in the Sprague-Dawley strain. Our results indicate the need to consider the effect of season and age of animals at the time of carcinogen administration on rat mammary carcinogenesis induction. However, the application of the results obtained in one strain of experimental animals may only lead to misleading conclusions., P. Kubatka, E. Ahlersová, I. Ahlers, B. Bojková, K. Kalická, E. Adámeková, M. Marková, M. Chamilová, M. Čermáková., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34355. Variability of seasonal floods in the Upper Danube River basin
- Creator:
- Jeneiová, Katarína, Kohnová, Silvia, Hall, Julia, and Parajka, Juraj
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- seasonality, summer and winter floods, upper danube river basin, and comparative hydrology
- Language:
- Slovak
- Description:
- The objective of this study is to analyse the spatial variability of seasonal flood occurrences in the Upper Danube region for the period 1961-2010. The analysis focuses on the understanding of the factors that control the spatial variability of winter and summer floods in 88 basins with different physiographic conditions. The evaluation is based on circular statistics, which compare the changes in the mean date and in the seasonal flood concentration index within a year or predefined season. The results indicate that summer half-year and winter half-year floods are dominant in the Alps and northern Danube tributaries, respectively. A comparison of the relative magnitude of flood events indicates that summer half-year floods are on average more than 50% larger than floods in winter. The evaluation of flood occurrence showed that the values of seasonal flood concentration index (median 0.75) in comparison to the annual floods (median 0.58) shows higher temporal concentration of floods. The flood seasonality of winter events is dominant in the Alps; however, along the northern fringe (i.e. the Isar, Iller and Inn River) the timing of winter half-year floods is diverse. The seasonal concentration of summer floods tends to increase with increasing mean elevation of the basins. The occurrence of the three largest summer floods is more stable, i.e. they tend to occur around the same time for the majority of analysed basins. The results show that fixing the summer and winter seasons to specific months does not always allow a clear distinction of the main flood generation processes. Therefore, criteria to define flood typologies that are more robust are needed for regions such as the Upper Danube, with large climate and topographical variability between the lowland and high elevations, particularly for the assessment of the effect of increasing air temperature on snowmelt runoff and associated floods.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34356. Variability of snow line elevation, snow cover area and depletion in the main Slovak basins in winters 2001-2014
- Creator:
- Krajčí, Pavel, Holko, Ladislav, and Parajka, Juraj
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- MODIS, snow line, snow cover, snow depletion curves, and Slovakia
- Language:
- Slovak
- Description:
- Spatial and temporal variability of snow line (SL) elevation, snow cover area (SCA) and depletion (SCD) in winters 2001-2014 is investigated in ten main Slovak river basins (the Western Carpathians). Daily satellite snow cover maps from MODIS Terra (MOD10A1, V005) and Aqua (MYD10A1, V005) with resolution 500 m are used. The results indicate three groups of basins with similar variability in the SL elevation. The first includes basins with maximum elevations above 1500 m a.s.l. (Poprad, Upper Váh, Hron, Hornád). Winter median SL is equal or close to minimum basin elevation in snow rich winters in these basins. Even in snow poor winters is SL close to the basin mean. Second group consists of mid-altitude basins with maximum elevation around 1000 m a.s.l. (Slaná, Ipeľ, Nitra, Bodrog). Median SL varies between 150 and 550 m a.s.l. in January and February, which represents approximately 40–80% snow coverage. Median SL is near the maximum basin elevation during the snow poor winters. This means that basins are in such winters snow free approximately 50% of days in January and February. The third group includes the Rudava/Myjava and Lower Váh/Danube. These basins have their maximum altitude less than 700 m a.s.l. and only a small part of these basins is covered with snow even during the snow rich winters. The evaluation of SCA shows that snow cover typically starts in December and last to February. In the highest basins (Poprad, Upper Váh), the snow season sometimes tends to start earlier (November) and lasts to March/April. The median of SCA is, however, less than 10% in these months. The median SCA of entire winter season is above 70% in the highest basins (Poprad, Upper Váh, Hron), ranges between 30-60% in the mid-altitude basins (Hornád, Slaná, Ipeľ, Nitra, Bodrog) and is less than 1% in the Myjava/Rudava and Lower Váh/Danube basins. However, there is a considerable variability in seasonal coverage between the years. Our results indicate that there is no significant trend in mean SCA in the period 2001-2014, but periods with larger and smaller SCA exist. Winters in the period 2002-2006 have noticeably larger mean SCA than those in the period 2007-2012. Snow depletion curves (SDC) do not have a simple evolution in most winters. The snowmelt tends to start between early February and the end of March. The snowmelt lasts between 8 and 15 days on average in lowland and high mountain basins, respectively. Interestingly, the variability in SDC between the winters is much larger than between the basins.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34357. Variability of the photosynthetic machinery tolerance when imposed to rapidly or slowly imposed dehydration in native Mediterranean plants
- Creator:
- Koutra, E., Chondrogiannis, C., and Grammatikopoulos, G.
- Format:
- počítač and online zdroj
- Type:
- model:article and TEXT
- Subject:
- drought factor index, integrated biomarker response, JIP-test, photosynthesis, plant growth forms, and water stress
- Language:
- Multiple languages
- Description:
- Dehydration affects the photosynthetic apparatus. The impact of dehydration on photosynthesis was assessed in twelve Mediterranean species representing different growth forms. Rapid and slow dehydration experiments were conducted to (1) compare the impact of water stress among species and growth forms, (2) rank species according to their drought tolerance. Rapid dehydration reduced the electron transport up to PSI, the reduction being linearly related to leaf relative water content (RWC), except for the deciduous species. Specific energy fluxes per reaction center and maximum photochemical activity of PSII remained relatively stable until 10-30% RWC. The modification pattern of the studied parameters was similar for all the growth forms. Slow rehydration increased specific energy fluxes and decreased quantum yields. The dehydration pattern was similar among growth forms, while the recovery pattern was species-specific. Drought tolerance ranking through drought factor index was relatively modified with the integrated biomarker response method.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34358. Variability of throughfall quantity in a mixed evergreen-deciduous broadleaved forest in central China
- Creator:
- Su, Lei , Xie, Zongqiang , Xu, Wenting , and Zhao, Changming
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- throughfall, spatial variability, temporal stability, mixed evergreen-deciduous broadleaved forest, and Shennongjia
- Language:
- Slovak
- Description:
- Mixed evergreen-deciduous broadleaved forest is the transitional type of evergreen broadleaved forest and deciduous broadleaved forest, and plays a unique eco-hydrologic role in terrestrial ecosystem. We investigated the spatiotemporal patterns of throughfall volume of the forest type in Shennongjia, central China. The results indicated that throughfall represented 84.8% of gross rainfall in the forest. The mean CV (coefficient of variation) of throughfall was 27.27%. Inter-event variability in stand-scale throughfall generation can be substantially altered due to changes in rainfall characteristics, throughfall CV decreased with increasing rainfall amount and intensity, and reached a quasi-constant level when rainfall amount reached 25 mm or rainfall intensity reached 2 mm h–1. During the leafed period, the spatial pattern of throughfall was highly temporal stable, which may result in spatial heterogeneity of soil moisture.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34359. Variable expression of hypercholesterolemia in apolipoprotein E2* (Arg136 - Cys) Heterozygotes
- Creator:
- Jaroslav Hubáček, Jan Piťha, Petr Stávek, Schmitz, G., and Rudolf Poledne
- Format:
- print, bez média, and svazek
- Type:
- article, články, model:article, and TEXT
- Subject:
- Fyziologie člověka a srovnávací fyziologie, sekvenování DNA, metabolismus lipidů, DNA sequencing, lipid metabolism, apolipoprotein E, rare mutation, PCR, 14, and 612
- Language:
- English
- Description:
- In the process of population screening for apo E gene polymorphism with the PCR and subsequent restriction analysis, we identified a female who demonstrated heterozygosity for an unusual restriction fragment caused by the loss of a CfoI restriction site. Sequence analysis of the apo E gene was performed and a carrier of the mutant allele with C - T substitution at cDNA position 3817 was identified, which caused an Arg136 - Cys change. The first-line relatives have been screened for this rare mutation with PCR and restriction analysis of PCR products. The complete lipoprotein parameters have been determined in the probands family. In the family, only one child had the same mutant allele as his mother had. The proband (7.49 mmol/l) with her siblings had hypercholesterolemia and a high body mass index (BMI 31.6 kg/m2). By contrast, her son had a normal lipid spectrum with normal BMI. We described the mutation apo E2* (Arg136 - Cys) in a family with elevated lipid levels, but there was no confirmation of the connection between this mutation and type III hyperlipoproteinemia or hyperlipoproteinemia at all. In the case of this mutation, other factors (mainly genetic) are important for the development of lipid metabolism disorders., J. A. Hubáček, J. Piťha, P. Stávek, G. Schmitz, R. Poledne., and Obsahuje bibliografii
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public
34360. Variable responses of mesophyll conductance to substomatal carbon dioxide concentration in common bean and soybean
- Creator:
- Bunce, J. A.
- Format:
- bez média and svazek
- Type:
- model:article and TEXT
- Subject:
- botanika, botany, Glycine max, light, Phaseolus vulgaris, and temperature
- Language:
- Multiple languages
- Description:
- Some reports indicate that mesophyll conductance (gm) to carbon dioxide varies greatly with the substomatal carbon dioxide concentration (Ci) during the measurement, while other reports indicate little or no change in g m with Ci. I used the oxygen sensitivity of photosynthesis to determine the response of gm to Ci over the range of about 100 to 300 μmol mol-1 Ci at constant temperature in common bean (Phaseolus vulgaris) and soybean (Glycine max) grown over a range of temperatures and photosynthetic photon flux densities (PPFD). In soybean grown and measured at high PPFD there was only a slight, approximately 15% decrease in gm with Ci over the range of 100 to 300 μmol mol-1. With lower PPFD during the measurement of gm, and especially with low PPFD during plant growth, there was a larger decrease in gm with Ci in soybean. In common bean, the same range in Ci resulted in about a 60% decrease in g m for plants grown and measured at high PPFD, with an even larger decrease for plants at low growth or measurement PPFD. Growth temperatures of 20 to 30°C had little influence on the response of gm to Ci or its absolute value in either species. It is concluded that these two species differed substantially in the sensitivity of gm to Ci, and that PPFD but not temperature during leaf development strongly affected the response of gm to Ci. and J. A. Bunce.
- Rights:
- http://creativecommons.org/licenses/by-nc-sa/4.0/ and policy:public