2,256 research outputs found

    Prolific development of pachythecaliines in Late Barremian, Bulgaria : coral taxonomy and sedimentary environment

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    Diversified and abundant corals of the suborder Pachythecaliina (order Hexanthiniaria) are described from Upper Barremian, biostromal reefs of the Emen Formation, Lovech Urgonian Group, north central Bulgaria. The corals are mostly of the phaceloid growth form and represent 14 species (six new), 12 genera (three new), belonging to five families. Pachythecaliines occur with the small, monopleurid cylindrical rudist Mathesia darderi. The rudists frequently are densely clustered, occur between coral branches or are in contact with them. Other corals, with the exception of the phaceloid Calamophylliopsis, and other rudists, are rare. Non-laminated microbialite crusts provided additional, structural support for bioconstruction development. Microbialites (automicrites) can be interpreted as a product of microbial activity, or alternatively, as a result of carbonate precipitation, brought about by non-living organic substrates (organomineralization s.s.). In addition to microbialites, metazoans are encrusted by heterotrophic skeletal microorganisms, while photophilic and oligotrophic microencrusters, usually common in other coral-bearing limestones of the Emen Formation, are very rare. The section at the Rusalya Quarry (NW of Veliko Tarnovo), about 42 m thick, provides the sedimentary and environmental context for the reefal biostromes. The vertical biotic and sedimentary succession displays a general shallowing trend: from the outer carbonate platform with bioclastic limestones containing small boundstone patches (corals, but not pachythecaliines, Lithocodium aggregatum), to the inner platform with rudist biostromes. The pachythecaliine-rich biostromes, 2.5 m thick, were developed in a low-energy environment, referred to the distal part of the rudist-dominated area of the platform. The development of microbialites was facilitated by a low sedimentation rate, and possibly by increased nutrient level. Only poorly diversified and non-phaceloid pachythecaliines occur in other coral-rich limestones and marls of the Urgonian complex in Bulgaria. The assemblage described is the most remarkable, Early Cretaceous coral community worldwide, with regard to pachythecaliines. Phaceloid pachythecaliines are only more common in the Upper Jurassic rocks, being particularly diversified in the Tithonian-Lower Berriasian Štramberk Limestone (Czech Republic) and its equivalent in the Polish Outer Carpathians. However, their sedimentary context differs from that described for the corals of the Emen Formation

    Comparison of dose rate when working with a C-arm X-ray system

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    Introduction: During working with sources of ionizing radiation, it is of special importance to take into account the dose load of the personnel working with such equipment.Aim: The aim of this article is to discuss the dose load of people working with mobile X-ray systems with a C-arm, who perform orthopedic procedures in the Clinic of Orthopedics and Traumatology of the St. Marina University Hospital, Varna. This research tries to convincingly show orthopedic surgeons and traumatologists that using a fluoroscopy mode (in all its variations) of the C-arm X-ray system when the tube is positioned under the patient table is best for their work when it comes to the working conditions, the image quality, the information value and the dose exposure of the staff.Materials and Methods: In the article a comparison of the dose load (effective dose) was made based on dosimetric measurements with respect to the personnel in different modes of operation of the X-ray equipment—roentgenoscopy (single shot) and fluoroscopy. The doses received by the surgeon-operator and his assistant were measured at three points of the body—head, gonads and feet, in radiography mode (single shot) and in three sub-modes of the fluoroscopy mode—continuous fluoroscopy, ½ dose fluoroscopy, and pulse fluoroscopy.For a more accurate comparison of the dose load in the respective operating modes, the time for reaching the dose limit for the personnel, determined by the Bulgarian legislation, was calculated—namely 20mSv per year.Results: The results of all measurements and calculations showed that the dose load in the radiography mode (single shot) was several times larger than the dose that was received in the three variations of the fluoroscopy mode at the same operating time.Conclusion: The results suggest that when using the fluoroscopy mode, even in the sub-mode with the highest dose load, it gives a lower dose than using the mode roentgenography, at the same time of operation of the X-ray tube

    Magnetoelectric effect and phase transitions in CuO in external magnetic fields

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    Apart from being so far the only known binary multiferroic compound, CuO has a much higher transition temperature into the multiferroic state, 230 K, than any other known material in which the electric polarization is induced by spontaneous magnetic order, typically lower than 100 K. Although the magnetically induced ferroelectricity of CuO is firmly established, no magnetoelectric effect has been observed so far as direct crosstalk between bulk magnetization and electric polarization counterparts. Here we demonstrate that high magnetic fields of about 50 T are able to suppress the helical modulation of the spins in the multiferroic phase and dramatically affect the electric polarization. Furthermore, just below the spontaneous transition from commensurate (paraelectric) to incommensurate (ferroelectric) structures at 213 K, even modest magnetic fields induce a transition into the incommensurate structure and then suppress it at higher field. Thus, remarkable hidden magnetoelectric features are uncovered, establishing CuO as prototype multiferroic with abundance of competitive magnetic interactions.Comment: 26 pages, 5 figure

    Prunus spinosa L. leaf extracts: polyphenol profile and bioactivities

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    Prunus spinosa leaf extracts in solvents of different polarity (water, ethanol and acetone), their phenol, flavonoid and anthocyanin contents and biological properties were the object of this study. The richest in phenols as well as in flavonoids was acetone extract with 181.19 mg GAE and 80.10 mg QE per gram of dry extract, respectively. Moreover, the quantity of anthocyanins obtained by HPLC analysis was also the highest in acetone sample. Examined samples possessed antioxidant properties evaluated through four in vitro assays (DPPH, ABTS, FRAP and TRC). The acetone extract was proved to be the best antioxidant among tested samples, which could be ascribed to polyphenols, especially anthocyanins. The aqueous and the ethanol extract exhibited antibacterial effects, being particularly active against B. cereus and E. cloacae. T. viride, P. funiculosum, P. ochrochloron, P. verrucosum var. cyclopium were the most susceptible among fungal microorganisms examined. Both, the aqueous and the ethanol extract expressed inhibitory activity towards enzymes linked to diabetes mellitus type II. Additionally, the ethanol extract showed significantly higher potential in inhibiting α-glucosidase than the drug used as the positive control. Furthermore, the aqueous sample revealed antitumor effects on following malignant cell lines: HeLa, K562 and MDA-MB-453. The results presented herein suggest that P. spinosa leaves should be considered as a natural source of bioactive compounds with potential application in phytopharmacy and food industry

    Examination of the polyphenol content and bioactivities of Prunus spinosa L. fruit extracts

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    We investigated the total phenolic and flavonoid contents and the anthocyanin profiles in aqueous, ethanol and acetone extracts of Prunus spinosa (Rosaceae) fruit, and their antioxidant, antibacterial, antifungal, antidiabetic and antitumor properties. The contribution of polyphenol contents to the bioactivity of the extracts was calculated and observed through Pearson’s coefficient of correlation. The acetone extract was the richest in phenols and anthocyanins and the ethanol extract in flavonoids. Cyanidin was the most abundant anthocyanin compound in all examined extracts. The ethanol extract showed the most promising antioxidant activity in DPPH, ABTS and FRAP assays. Tested bacteria were more affected by the ethanol than by the aqueous extract. Both the ethanol and aqueous extracts exhibited potential antidiabetic effects, observed as inhibition of α-amylase and α-glucosidase, enzymes linked with diabetes mellitus type II. The ethanol extract was a potent α-glucosidase-inhibitor with a significantly lower IC50 value than the positive control, glucobay, used to treat diabetes mellitus type II. Neither the ethanol nor the aqueous extracts had any effects on tested human malignant cell lines. Our results indicate that the ethanol extract showed the most pronounced in vitro antioxidant and antimicrobial effects, and a potential antidiabetic activity, which can be ascribed to its high flavonoid content. Our results indicate that research of compounds, particularly of flavonoids present in the ethanol extract and their anti-diabetic properties should be examined further

    Evolution of Integrated MEMS Design Methodology

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    Abstract -The long term impact of MEMS technology will be in its ability to integrate novel sensing and actuation functionality on traditional computing and communication devices enabling the ubiquitous digital computer to interact with the world around it. The design and verification of such integrated systems will occur at the system level, driven primarily by the application [1]. Therefore application-driven system level design methodologies are needed to ease the integration of the digital area to the real world using mixed area technologies

    The effect of gross primary production, net primary production and net ecosystem exchange on the carbon fixation by chemical weathering of basalt in northeastern Iceland,

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    Abstract The overall objective of this study is to define and interpret the annual dissolved inorganic carbon (DIC) flux in selected river catchments in North Eastern Iceland. The flux stems primarily from chemical weathering of basalt. The DIC flux out of the catchments is compared with the spatial distribution of the various vegetation communities and their gross primary production (GPP), net primary production (NPP) and net ecosystem exchange (NEE). There is no correlation between the DIC flux and the GPP, but one between DIC and NPP. The DIC flux is highly dependent on the NEE, which in turn is governed by the area extent of wetlands in these catchments. A variation by a factor 5 of the NEE results in a variation by a factor 2.8 in the river dissolved inorganic flux.

    Magnetoelectric effect and phase transitions in CuO in external magnetic fields

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    Apart from being so far the only known binary multiferroic compound, CuO has a much higher transition temperature into the multiferroic state, 230 K, than any other known material in which the electric polarization is induced by spontaneous magnetic order, typically lower than 100 K. Although the magnetically induced ferroelectricity of CuO is firmly established, no magnetoelectric effect has been observed so far as direct crosstalk between bulk magnetization and electric polarization counterparts. Here we demonstrate that high magnetic fields of E50 T are able to suppress the helical modulation of the spins in the multiferroic phase and dramatically affect the electric polarization. Furthermore, just below the spontaneous transition from commensurate (paraelectric) to incommensurate (ferroelectric) structures at 213 K, even modest magnetic fields induce a transition into the incommensurate structure and then suppress it at higher field. Thus, remarkable hidden magnetoelectric features are uncovered, establishing CuO as prototype multiferroic with abundance of competitive magnetic interactions

    Assessment of long-range correlation in animal behaviour time series: the temporal pattern of locomotor activity of Japanese quail (Coturnix coturnix) and mosquito larva (Culex quinquefasciatus)

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    The aim of this study was to evaluate the performance of a classical method of fractal analysis, Detrended Fluctuation Analysis (DFA), in the analysis of the dynamics of animal behavior time series. In order to correctly use DFA to assess the presence of long-range correlation, previous authors using statistical model systems have stated that different aspects should be taken into account such as: 1) the establishment by hypothesis testing of the absence of short term correlation, 2) an accurate estimation of a straight line in the log-log plot of the fluctuation function, 3) the elimination of artificial crossovers in the fluctuation function, and 4) the length of the time series. Taking into consideration these factors, herein we evaluated the presence of long-range correlation in the temporal pattern of locomotor activity of Japanese quail ({\sl Coturnix coturnix}) and mosquito larva ({\sl Culex quinquefasciatus}). In our study, modeling the data with the general ARFIMA model, we rejected the hypothesis of short range correlations (d=0) in all cases. We also observed that DFA was able to distinguish between the artificial crossover observed in the temporal pattern of locomotion of Japanese quail, and the crossovers in the correlation behavior observed in mosquito larvae locomotion. Although the test duration can slightly influence the parameter estimation, no qualitative differences were observed between different test durations

    Floatainer, plataforma modular flutuante: proposta ao concurso UnBox 2017

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    This article aims to present a proposal recently designed by students of the Architecture and Urbanism Course of the Federal University of Santa Maria Campus of Cachoeira do Sul in an international competition of architecture and design promoted by the portal Volume Zero, “UnBox 2017”, wich proposed ways to creatively rethink the discard of containers in the contemporary world. The final result was punctuated by a distinguished architecture value, especially due to the flexibility of its program and its deployment location. However, its highest value is its social importance: the materiality is mainly composed of reused elements - containers and plastic drums (chosen precisely because of its reusable character, just as containers) -, making it environmentally, socially and economically sustainable. Another pertinence factor to be explored is the resulting knowledge to the students through the participation in competitions of architecture and design. Therefore, the practice of participation in competitions that stimulate creativity, innovation and the search for tools for sustainable development is considered totally positive.Este trabalho apresenta os desafios da proposta projetual recentemente realizada por alunos do Curso de Arquitetura e Urbanismo da Universidade Federal de Santa Maria do Campus de Cachoeira do Sul em um concurso internacional de arquitetura e design promovido pelo portal Volume Zero, que, através do concurso “UnBox 2017”, propunha formas de repensar criativamente o descarte de contêineres no mundo contemporâneo. O resultado final obtido foi dotado de significativo valor arquitetônico, em especial devido à flexibilidade de seu programa de necessidades e de seu local de implantação. Sua maior contribuição se dá através dos valores ambientais, sociais e economicamente sustentáveis, evidenciado por sua materialidade composta majoritariamente por elementos reutilizados: contêineres e tambores plásticos. Outro fator relevante foi o conhecimento resultante da experiência oferecida aos acadêmicos por meio da participação em concurso internacional de arquitetura e design. Por conseguinte, considera-se totalmente positiva a prática de participação em competições que estimulem a criatividade, a inovação e a busca por ferramentas ao desenvolvimento sustentável
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