709 research outputs found

    Time-Resolved in situ Raman Spectroscopic Observations of a Biomineralization Model System

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    The mechanisms underlying the formation of nanocrystalline apatite in vertebrate hard tissues (i.e. bones and teeth) remain nebulous. The long-held view of biomineralization via “classical crystallization theory”, or ion-by-ion addition from solution, is challenged by “non-classical” theories in which the pathway proceeds through transient precursor phases [1]. The presence of an amorphous calcium phosphate (ACP) mineral precursor has been observed during the formation of zebrafish fin bones and dental enamel [2, 3]. However, the sample preparation necessary for electron microscopy and ethical considerations inherent to vertebrate samples preclude in situ observations of apatite mineralization

    Diversity and Abundance of Microbial Communities in UASB Reactors during Methane Production from Hydrolyzed Wheat Straw and Lucerne

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    The use of straw for biofuel production is encouraged by the European Union. A previous study showed the feasibility of producing biomethane in upflow anaerobic sludge blanket (UASB) reactors using hydrolyzed, steam-pretreated wheat straw, before and after dark fermentation withCaldicellulosiruptor saccharolyticus, and lucerne. This study provides information on overall microbial community development in those UASB processes and changes related to acidification. The bacterial and archaeal community in granular samples was analyzed using high-throughput amplicon sequencing. Anaerobic digestion model no. 1 (ADM1) was used to predict the abundance of microbial functional groups. The sequencing results showed decreased richness and diversity in the microbial community, and decreased relative abundance of bacteria in relation to archaea, after process acidification. Canonical correspondence analysis showed significant negative correlations between the concentration of organic acids and three phyla, and positive correlations with seven phyla. Organic loading rate and total COD fed also showed significant correlations with microbial community structure, which changed over time. ADM1 predicted a decrease in acetate degraders after a decrease to pH <= 6.5. Acidification had a sustained effect on the microbial community and process performance

    Syncope prediction scores in the Emergency Department

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    Abstract: Syncope is a common clinical presentation defined as a transient loss of consciousness (TLOC) due to cerebral hypoperfusion, characterized by a rapid onset, short duration, and spontaneous complete recovery. Different clinical decision rules (CDRs) and risk stratification scores have been developed to predict short- and long-term risks for adverse outcomes after syncope. The central theme of these prediction systems is consistent with the ESC syncope guidelines. Initial assessment according to the ESC guideline is essential until an optimal and well-validated risk score is available. The focus should be accurate risk stratification to allow prevention of adverse outcomes and optimize the use of limited healthcare resources. In this review article, we summarize and critically appraise the evidence regarding the CDRs for patients presenting with syncope

    Clinical significance, challenges and limitations in using artificial intelligence for electrocardiography-based diagnosis

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    Cardiovascular diseases are one of the leading global causes of mortality. Currently, clinicians rely on their own analyses or automated analyses of the electrocardiogram (ECG) to obtain a diagnosis. However, both approaches can only include a finite number of predictors and are unable to execute complex analyses. Artificial intelligence (AI) has enabled the introduction of machine and deep learning algorithms to compensate for the existing limitations of current ECG analysis methods, with promising results. However, it should be prudent to recognize that these algorithms also associated with their own unique set of challenges and limitations, such as professional liability, systematic bias, surveillance, cybersecurity, as well as technical and logistical challenges. This review aims to increase familiarity with and awareness of AI algorithms used in ECG diagnosis, and to ultimately inform the interested stakeholders on their potential utility in addressing present clinical challenges

    Collection and consumption of echinoderms and crustaceans at the Mesolithic shell midden site of El Mazo (northern Iberia) : Opportunistic behaviour or social strategy?

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    Recent studies in Atlantic Europe on crab remains, goose barnacles and sea urchins have revealed that these species can be of great help in determining patterns of shellfish collection and providing new information on subsistence strategies of hunter-fisher-gatherers. Current excavations at the Mesolithic shell midden site of El Mazo cave (Asturias, northern Iberia) have produced a sizeable amount of crustacean and echinoderm remains from a long stratigraphic sequence that covers an important part of the Mesolithic chronological range, providing the opportunity to investigate long-term exploitation patterns. Results show that echinoderms (sea urchins) and crustaceans (goose barnacles and crabs) were present throughout all of the stratigraphic units (from 8.9 to 7.6 cal kyr), suggesting that they were a persistently exploited food source. However, these resources were not intensively exploited, save perhaps sea urchins at the base of the sequence. From a quantitative perspective, these resources have been traditionally interpreted as minor resources exploited opportunistically to help group survival. However, given the pattern of continuous exploitation exhibited by these resources in northern Iberia and other areas of Atlantic Europe, we suggest that they can be interpreted from a qualitative perspective as stable resources with a significant social valu

    The relations between morphological awareness and reading comprehension in beginner readers through to young adolescents

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    Background. Morphological awareness plays a crucial role in supporting higher level text processing. We examined its contribution to reading comprehension in children of different ages and ability levels in order to determine when and for whom morphological awareness is of particular importance. Methods. Three groups of children (aged 6-8 years, N=128; 9-11 years, N=126; and 12-13 years N=147) completed judgement and production tasks to measure awareness of compounding, inflections, and derivations. Non-verbal reasoning, vocabulary, phonological awareness, word reading and reading comprehension were also assessed. Results. Principal components analysis yielded a single primary factor of morphological awareness for each age group. Separate hierarchical multiple regressions revealed that this morphological awareness factor accounted for significant unique variance in reading comprehension for groups of 6-8 years and 12-13 years, beyond age, non-verbal reasoning, vocabulary, phonological awareness and word reading. Vocabulary also uniquely predicted reading comprehension in all three age groups. Quantile regression analyses at three points in the reading comprehension distribution (0.1, 0.5, 0.9) indicated that morphological awareness and vocabulary predicted reading comprehension to a similar extent across the ability range. Conclusions. Our results clarify the fundamental role of morphological awareness in reading comprehension across all levels of readers. In addition, vocabulary and morphological awareness each make critical contributions to comprehension ability in developing readers across the ability range

    Polarization control proposal for Shanghai deep ultraviolet free electron laser

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    In this paper, a fully coherent radiation option with controllable polarization is proposed for Shanghai deep ultraviolet free electron laser (FEL) test facility. Intensive start-to-end simulation suggests that, the two crossed planar undulators which generate the horizontal and vertical linear polarized FEL respectively, should be placed as close as possible for avoiding the polarization performance degradation of the final combined FEL radiation. With the existence of the phase-shifter between the two crossed radiators, Fourier-Transform-Limited output radiation with 100 nJ order pulse energy, 5 ps full pulse length and circular polarization degree above 90% could be achieved.Comment: 9 pages, 5 figures, 1 tabl
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