67 research outputs found

    Osady dna doliny Nidzicy w rejonie Kazimierzy Wielkiej

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    The significance of log and boulder steps for diversification of fluvial sediments characteristics in a stream channel in a small forest catchment in the Polish Carpathians

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    The study presents the diversification of sediments deposited on log (LS), boulder (BS) and mixed-type (LBS) steps located in the channel of a stream in a small forest mountain catchment in the Polish Carpathians. The topic of sediment diversification in a stream channel is an important issue not only from the perspective of sediment transport process and shaping fluvial systems in forested catchments caused by woody or rock debris but also in the context of functioning of local ecosystems. We aimed to test the following hypothesis: the morphodynamic features of a stream channel and the type of steps therein significantly affect the diversification of the size and shape of mineral deposits and play an important role in the process of sediments transport and processing in the channels of small mountain streams. In order to verify the above hypothesis, sediments were sampled directly from the stream channel (Ch) in its longitudinal profile as well as upstream and downstream of steps (LS, BS and LBS) in the channel. The diversification of features of sediment grain size was analysed taking into account step type and sediment location in the longitudinal profile of the stream channel. The research was conducted separately for fine-grained sandstone (A) and coarse-grained sandstone (B). In addition, the basic sedimentological indicators and the shape parameter of the gravels, as described by the Zingg method, were determined. In order to determine the transport predisposition of the sediments in a specific load, an analysis of sediment distribution was performed on the C/M (C-first percentile and M-median) diagram. The PCA (Principal component analysis) analysis showed that the step type significantly affects the processing as well as the size and shape diversification of mineral deposits, which confirms our hypothesis. Therefore, this study is a contribution to the current knowledge on fluvial processes occurring in stream channels in small forest mountain catchments

    Variances in the present-day alluvia in the Lepietnica river channel

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    Climate conditions of the present-day relief development on Cape Verde Islands

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    Cape Verde Islands are an example of a local diversity of the semi-arid equatorial climate zone. The type and intensity of the present-day morphogenetic processes is determined mostly by total precipitation and vegetation cover. We can distinguish three types of relief development. In the warm, arid climate conditions throughout the year, volcanic forms are very slowly changed or preserved by the action of episodic water, limited to a material redeposition in the wadi channels and sand dune forming by the wind. In the semi-arid climate conditions, volcanic forms are transformed into denudationfl uvial relief in the rain period. It is visible mainly on the windward side of islands and at a lower altitude, where the weathering material is washed from slopes and carried away down the wadi channels to the sea after periodic torrential rains. At the same time on the leeward side, at a higher altitude and in agricultural areas only a small amount of material is transported over short distance

    Textural features of bed material of the Wilga River as a reflection of the channel structure diversity and sources of material supply to the fluvial system

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    Wykształcenie i funkcjonowanie koryt rzecznych uwarunkowane jest cechami środowiska przyrodniczego zlewni oraz antropopresją. Uwarunkowania te mają zasadnicze znaczenie w kształtowaniu cech osadów aluwialnych. Głównym celem badań było poznanie zróżnicowania cech teksturalnych współczesnych osadów korytowych Wilgi w nawiązaniu do zróżnicowania struktury jej koryta oraz źródeł dostawy materiału do systemu fluwialnego. Scharakteryzowano strukturę koryta Wilgi ze szczególnym uwzględnieniem rozmieszczenia i cech form akumulacyjnych oraz erozyjnych. Na czterech stanowiskach badawczych, powiązanych z różnymi źródłami dostawy, określono uziarnienie osadów korytowych, ich skład petrograficzny i stopień obróbki. Uzyskane wyniki pokazały zróżnicowanie źródeł dostawy materiału wzdłuż profilu podłużnego koryta. W pogórskim odcinku źródłami dostawy są podcięcia erozji bocznej oraz progi w dnie koryta. Materiał aluwialny w korycie jest ostrokrawędzisty i grubofrakcyjny. W niżej położonej części zlewni, do koryta dostarczany jest materiał drobnoziarnisty budujący szerokie, płaskie dno doliny. Stwierdzono również, że wzdłuż profilu podłużnego koryta największym zmianom ulega uziarnienie oraz stopień obróbki materiału, w mniejszym stopniu skład petrograficzny.The structure and functioning of river bed are conditioned by the natural environment and human activity. These conditions significantly affect the texture of the channel material. The main aim of the research was to study the texture of bed material and their variability in the present-day alluvium in the channel of Wilga River. The structure of the Wilga River bed was described. The main focus was on the distribution and location of accumulation and erosion forms. On four study sites, related to sediment sources, grain size distributions, petrographic composition, and degree of rounding were analysed. The obtained results show how the sources of material differ in the longitudinal profile. In the foothills sources are connected with lateral erosion and occurrence of channel steps. The alluvial material is angular and has a larger grain size. In lower part of the catchment, bed material is fine and builds a wide, flat valley floor. Research shows that the biggest changes in the longitudinal profile are connected with grain size and degree of rounding and to a lesser extent in the petrographic composition

    Effect of treatment on systemic cytokines in head and neck squamous cell carcinoma patients

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    The aim of this study was to determine the effect of HNSCC tumour treatment on systemic Th1 and Th2 cytokine levels and investigate correlations with clinicopathological parameters. IL2, IL4, IL5, IL6, IL8, IL10, IL13, GMCSF, IFNγ and TNFα were measured in the serum of 101 newly-presenting HNSCC patients (9 oral cavity, 27 oropharynx, 57 laryngopharynx, 1 sinonasal, 1 parotid and 6 unknown), prior to and following treatment, using a Quantibody® array based multiplex sandwich ELISA (Raybiotech). Data were analysed with respect to T stage, nodal status, age and sex of the patient as well as time between collection of pre- and post-treatment serum. A significant decrease in the levels of the Th2 cytokines IL4, IL5, IL6 and IL10 and the Th1 cytokines IL2 and IL8 was observed between the pre- and post-treatment serum samples. IL13 and TNFα were significantly higher in early stage (T1/T2) tumours compared with late stage (T3/T4) and this trend was maintained for nodal involvement. IL4 was higher in node positive patients compared with node negative, whereas the converse was true for IL2; IL4 was also higher in younger patients compared with the older age group. These results suggest that removal of HNSCC tumours from patients results in reduced circulating Th2 cytokines without a concurrent increase in Th1 cytokines, indicative of a partial rebalance of the Th1/Th2 system following treatment. Furthermore the cytokine profile may be influenced by the size and nodal involvement of the tumour
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