2,173 research outputs found

    Analysis of Tourism Service Quality in Kołobrzeg Region by Means of Time Series Models

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    The undertaken study shows that methods that take into account time series can be successfully used in analysis of parameters of tourist comfort and in evaluation of hotel services.Przeprowadzone badania wskazują, że metody szeregów czasowych mogą być skutecznie zastosowane w badaniu wskaźników turystycznych i ocenie jakości usług hotelarskich

    Iron-mediated Preparation of Vinylcyclopropanes. Scope, Mechanism, and Applications

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    The addition of stabilized carbon nucleophiles to tricarbonyl(1-methoxycarbonylpentadienyl)iron(1+) cation (1a) proceeds via attack at C2 on the face of the ligand opposite the Fe(CO)3 group to generate tricarbonyl(pentenediyl)iron complexes 2. Oxidation of complexes 2 affords vinylcyclopropanecarboxylates in good yield. In general, the relative stereochemistry about the cyclopropane ring reflects reductive elimination with retention of configuration. In cases where the C2 substituent is bulky (i.e., 2b) the major cyclopropane product 9b represents ring closure with inversion at C3. A mechanism involving π−σ−π rearrangement of the initially oxidized (pentenediyl)iron species is proposed to account for these results. Experiments which probe the stereochemistry of deuterium labeling in the vinyl group of the vinylcyclopropanecarboxylate products were carried out, and these results are consistent with the proposed mechanism. This methodology for the preparation of vinylcyclopropanecarboxylates was applied to the synthesis of 2-(2‘-carboxycyclopropyl)glycines (+)-22 and (−)-23 and the cyclopropane triester (−)-26

    Analysis of senescence-like growth arrest induced by RUNX1 and its fusion derived oncoproteins

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    Cellular senescence is an end point of a signal transduction programme leading to irreversible cell cycle arresst accompanied by characteristic alterations to cell morphology, biochemical properties and gene expression profile. This phenotype can be triggered by a variety of stimuli including telomere shortening, DNA damage or activated oncogenes. Senescence is now recognised as a tumour suppressor mechanism mediated by p53 and pRB pathways which act to prevent the proliferatio of cells that are at risk of tumourigenic transformation. RUNX1 is a transcription factor essential for definitive hematopoiesis and is frequently targeted in human leukaemias by chromosomal rearrangements. RUNX1 has been also demonstrated to act as a dominant oncogene in mice and the ectopic expression of RUNX1 in murine embryonic fibroblasts has been shown to cause senescence. The central aim of this study was to investigate the mechanism of senescence induction by RUNX1 and its fusion derived leukaemogenic oncoproteins in primary fibroblasts. My work showed that RUNX1 induces a strong senescence-like response in murine and human primary fibroblasts that requires intact DNA binding, CBFB interaction and C-terminal transcriptional activation/repression domains. However, surprising differences were found between the major RUNX1 fusion oncoprotein derivatives. The N-terminal fusion protein TEL-RUNX1 fails to induce senescence despite retention of a virtually full-lenght RUNX1 moiety, while the senescence-inducing potential is exaggerated in the truncated C-terminal fusion protein RUNX1-ETO (AML1-ETO). The potential to drive senescence is retained by the deletion mutant RUNX1-ETO[]469 which lacks critical corepressor binding sites suggesting that the repression of target genes may be a primary mechanism implicated in RUNX1-ETO induced senescence. Interestingly, CBFB-MYH11 fusion oncoprotein that affects RUNX1 indirectly by targeting CBFB cn also induce senescence when ectopically expressed in human primary cells. The RUNX1 and RUNX1-ETO induced senescent phenotypes differ from archetypal H-Ras [superscript v12] as arrest occurs without a preliminary phase of proliferation and the arrested cells lack prominent foci of DNA strand breaks and chromatin condensation. Notably however, RUNX1 and RUNX1-ETO display differences in their potency and the extent of engagement of p53 and Rb effector pathways. RUNX1-ETO is highly dependent on p53 function and unlike RUNX1 drives senescence in cells lacking intact p16Ink4a. RUNX1-ETO appears to exert its unique effects through potent induction of reactive oxygen species and p38MAPK phosphorylation. These findings illustrate the heterogeneous manifestations of senescence-like growth arrest and elucidate the distinctive biology and oncogenic properies of RUNX1 and its fusion derivatives

    Concentration of Three Heavy Metals in Five Tissues of Fish Barbus sharpeyi, Aspius vorax, Silurus triostegus and Mystus pelusius Collected from Euphrates River Thi Qar, Iraq

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    The present study was conducted to investigate some heavy metals : Cd , Cu , and Zn in the tissue of fishes : Barbus sharpeyi Heckel , Aspius vorax Heckel , Silurus triostegus Heckel and Mystus pelusius Solander from the Euphrates River in the area between the town of Batha and the city of Nasiriyah . Samples were collected in July 2015. Where elements showed concentrations in the tissues of varying the four species of fish and Barbus sharpeyi as well as  high concentrations of cadmium from the rest of the fish careless and that the highest rate of cadmium record in the gills totaled 18.191ppm . As , it turns out that the Barbus sharpeyi fish showed significantly more than the accumulation of copper amounted to 58.7760 ppm and recorded the lowest concentrations in Mystus pelusius amounted to 13.550 ppm and the highest rate recorded in the liver was 77.951ppm . And, recording zinc big increase in the thickness of running totaled 146.4250 ppm followed Aspius vorax reached 66.7960 ppm and the highest rate recorded in gills totaled 114.022 ppm and less focus record in the muscles 52.599 ppm  .The results showed significant differences between the fish and the tissue. The findings current indicate high concentrations exceed determinants International approved by the FAO points out the diversity of sources of pollution with heavy and makes life good fish guides to study pollution recommend the establishment of an environmental monitoring system continuously. Keywords: Cadmium, Copper and Zin

    The Impact of the Covid-19 Pandemic on Eating Behavior among Adults Poles

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    Background: Due to the outbreak of coronavirus disease (COVID-19), many restrictions and temporary lockdown were carried out. As a result, previous lifestyle, including diet, were disrupted.Objectives: The aim of this review was to assess changes in eating behavior during the COVID-19 compared to the period before pandemic in Poland. Methods: In the review involved original studies concerning adults Poles (aged ≥ 18), including changes in their eating behavior.Results: The COVID-19 pandemic and the social isolation periods had ambiguous influence on diet in Poland. The changes were dependent on many factors e.g. age, sex, education, occupation, or body weight. In general, regular diet pattern was followed. In case of changes, positive and negative eating habits were observed. Improper eating behavior such as the increase of total food and junk food intake was noticed, however improvement of the diet also was observed. Consumption of healthy food, such as vegetables and fruit went up. The significant increase of home cooking also was noticed.Conclusions: The present review indicates the need for future strategies to assess nutrition in cases of alarming situations. Promoting healthy eating behavior appears to be essential, especially during the pandemic

    Evaluation of the Importance of Time-Frequency Contributions to Speech Intelligibility in Noise

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    Recent studies on binary masking techniques make the assumption that each time-frequency (T-F) unit contributes an equal amount to the overall intelligibility of speech. The present study demonstrated that the importance of each T-F unit to speech intelligibility varies in accordance with speech content. Specifically, T-F units are categorized into two classes, speech-present T-F units and speech-absent T-F units. Results indicate that the importance of each speech-present T-F unit to speech intelligibility is highly related to the loudness of its target component, while the importance of each speech-absent T-F unit varies according to the loudness of its masker component. Two types of mask errors are also considered, which include miss and false alarm errors. Consistent with previous work, false alarm errors are shown to be more harmful to speech intelligibility than miss errors when the mixture signal-to-noise ratio (SNR) is below 0 dB. However, the relative importance between the two types of error is conditioned on the SNR level of the input speech signal. Based on these observations, a mask-based objective measure, the loudness weighted hit-false, is proposed for predicting speech intelligibility. The proposed objective measure shows significantly higher correlation with intelligibility compared to two existing mask-based objective measures

    Design and Simulation of Modular Multilevel Converter Fed Induction Motor Drive

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    Traditional modular multilevel converter (MMC) applications in medium voltage induction motor drive are difficult, particularly at low speeds because of the higher magnitude of the voltage ripple of the sub-module capacitor. This paper uses a hybrid MMC, particularly at low frequencies, to achieve a lower peak-to-peak voltage ripple of the sub-module capacitor. The vector control strategy with the closed-loop speed control indicates an accurate and wide-speed range. MATLAB / Simulink is used to simulate and obtain the simulation results of hybrid and traditional MMC with induction motor drive and compare from the standpoint of capacitor voltage ripple. The results are shown the reduction of peak-to-peak voltage ripple of the sub-module capacitor as the hybrid MMC is operated
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