347 research outputs found

    Degradation of Rutin by Aspergillus flavus STUDIES WITH OXYGEN 18 ON THE ACTION OF A DIOXYGENASE ON QUERCETIN

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    Abstract The enzymatic oxygenation and cleavage of quercetin by quercetinase, an oxygenase produced by Aspergillus flavus, yield carbon monoxide and a depside, 2-protocatechuoyl-phloroglucinolcarboxylic acid. The enzyme does not incorporate oxygen from 18O2 into carbon monoxide, but incorporates both atoms of 18O2 into the depside. One atom of 18O2 is incorporated into the carboxyl group and the other into the ester carbonyl; thus quercetinase is a dioxygenase. Oxygen from H218O is not incorporated into either the depside or carbon monoxide. Both the carbon and oxygen of carbon monoxide are derived from the hydroxylated carbon 3 of quercetin. The reaction probably involves a direct and concerted addition of "activated oxygen" to quercetin at positions 2 and 4 to form an unstable cyclic peroxide intermediate which rapidly decomposes to give the products

    On Objective Measures of Rule Surprisingness

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    Most of the literature argues that surprisingness is an inherently subjective aspect of the discovered knowledge, which cannot be measured in objective terms. This paper departs from this view, and it has a twofold goal: (1) showing that it is indeed possible to define objective (rather than subjective) measures of discovered rule surprisingness; (2) proposing new ideas and methods for defining objective rule surprisingness measures

    Cerulean: A hybrid assembly using high throughput short and long reads

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    Genome assembly using high throughput data with short reads, arguably, remains an unresolvable task in repetitive genomes, since when the length of a repeat exceeds the read length, it becomes difficult to unambiguously connect the flanking regions. The emergence of third generation sequencing (Pacific Biosciences) with long reads enables the opportunity to resolve complicated repeats that could not be resolved by the short read data. However, these long reads have high error rate and it is an uphill task to assemble the genome without using additional high quality short reads. Recently, Koren et al. 2012 proposed an approach to use high quality short reads data to correct these long reads and, thus, make the assembly from long reads possible. However, due to the large size of both dataset (short and long reads), error-correction of these long reads requires excessively high computational resources, even on small bacterial genomes. In this work, instead of error correction of long reads, we first assemble the short reads and later map these long reads on the assembly graph to resolve repeats. Contribution: We present a hybrid assembly approach that is both computationally effective and produces high quality assemblies. Our algorithm first operates with a simplified version of the assembly graph consisting only of long contigs and gradually improves the assembly by adding smaller contigs in each iteration. In contrast to the state-of-the-art long reads error correction technique, which requires high computational resources and long running time on a supercomputer even for bacterial genome datasets, our software can produce comparable assembly using only a standard desktop in a short running time.Comment: Peer-reviewed and presented as part of the 13th Workshop on Algorithms in Bioinformatics (WABI2013

    The expression of classical rhetoric in televisual advertising : Portraying science and scientists.

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    The origins of classical rhetoric are to be found in Greece of the 4th and 5th centuries BCE. Developed principally for spoken delivery, though sometimes applied to written work, it became a much sought after skill due to the newly emerging democracies in the city-states. It was the refinement of the Greek philosophers' fundamental principles for the practice of classical rhetoric by their Roman successors, during the last century BCE and the first century CE, that later established its robust canonical structure.After drawing on semiotic wisdom in order to interpret the meanings embedded in illustrations and advertising film the following research shows to what degree classical rhetoric has a visual expression in which those ancient canonical principles have contemporary relevance rendering it a major mechanism in the persuasive function of television advertising. In so doing its contribution to knowledge comprises an innovative analytical methodology whilst also exposing a link, previously unremarked upon by scholars in the field, whereby the canon of classical rhetoric known as arrangement can be seen to have a common structural basis with narrative.Touching on the use of scientists, often presented as figures of unquestionable authority in televisual advertising during the middle part of the last century, this thesis now finds a more subtle rhetoric directed at an increasingly more media-aware culture in the third millennium. It will be suggested, however, that such rhetorical devices, as are revealed to be operating, are more likely to be as a result of intuition and empirical adroitness rather than being born of academically acquired knowledge on the part of creative media personnel

    Attachment Styles Within the Coach-Athlete Dyad: Preliminary Investigation and Assessment Development

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    The present preliminary study aimed to develop and examine the psychometric properties of a new sport-specific self-report instrument designed to assess athletes’ and coaches’ attachment styles. The development and initial validation comprised three main phases. In Phase 1, a pool of items was generated based on pre-existing self-report attachment instruments, modified to reflect a coach and an athlete’s style of attachment. In Phase 2, the content validity of the items was assessed by a panel of experts. A final scale was developed and administered to 405 coaches and 298 athletes (N = 703 participants). In Phase 3, confirmatory factor analysis of the obtained data was conducted to determine the final items of the Coach-Athlete Attachment Scale (CAAS). Confirmatory factor analysis revealed acceptable goodness of fit indexes for a 3-first order factor model as well as a 2-first order factor model for both the athlete and the coach data, respectively. A secure attachment style positively predicted relationship satisfaction, while an insecure attachment style was a negative predictor of relationship satisfaction. The CAAS revealed initial psychometric properties of content, factorial, and predictive validity, as well as reliability

    Tidal Venuses: Triggering a Climate Catastrophe via Tidal Heating

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    Traditionally stellar radiation has been the only heat source considered capable of determining global climate on long timescales. Here we show that terrestrial exoplanets orbiting low-mass stars may be tidally heated at high enough levels to induce a runaway greenhouse for a long enough duration for all the hydrogen to escape. Without hydrogen, the planet no longer has water and cannot support life. We call these planets "Tidal Venuses," and the phenomenon a "tidal greenhouse." Tidal effects also circularize the orbit, which decreases tidal heating. Hence, some planets may form with large eccentricity, with its accompanying large tidal heating, and lose their water, but eventually settle into nearly circular orbits (i.e. with negligible tidal heating) in the habitable zone (HZ). However, these planets are not habitable as past tidal heating desiccated them, and hence should not be ranked highly for detailed follow-up observations aimed at detecting biosignatures. Planets orbiting stars with masses <0.3 solar masses may be in danger of desiccation via tidal heating. We apply these concepts to Gl 667C c, a ~4.5 Earth-mass planet orbiting a 0.3 solar mass star at 0.12 AU. We find that it probably did not lose its water via tidal heating as orbital stability is unlikely for the high eccentricities required for the tidal greenhouse. As the inner edge of the HZ is defined by the onset of a runaway or moist greenhouse powered by radiation, our results represent a fundamental revision to the HZ for non-circular orbits. In the appendices we review a) the moist and runaway greenhouses, b) hydrogen escape, c) stellar mass-radius and mass-luminosity relations, d) terrestrial planet mass-radius relations, and e) linear tidal theories. [abridged]Comment: 59 pages, 11 figures, accepted to Astrobiology. New version includes an appendix on the water loss timescal

    Conceptual design of the early implementation of the NEutron Detector Array (NEDA) with AGATA

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    The NEutron Detector Array (NEDA) project aims at the construction of a new high-efficiency compact neutron detector array to be coupled with large (Formula presented.) -ray arrays such as AGATA. The application of NEDA ranges from its use as selective neutron multiplicity filter for fusion-evaporation reaction to a large solid angle neutron tagging device. In the present work, possible configurations for the NEDA coupled with the Neutron Wall for the early implementation with AGATA has been simulated, using Monte Carlo techniques, in order to evaluate their performance figures. The goal of this early NEDA implementation is to improve, with respect to previous instruments, efficiency and capability to select multiplicity for fusion-evaporation reaction channels in which 1, 2 or 3 neutrons are emitted. Each NEDA detector unit has the shape of a regular hexagonal prism with a volume of about 3.23l and it is filled with the EJ301 liquid scintillator, that presents good neutron- (Formula presented.) discrimination properties. The simulations have been performed using a fusion-evaporation event generator that has been validated with a set of experimental data obtained in the 58Ni + 56Fe reaction measured with the Neutron Wall detector array

    The Mathematical Universe

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    I explore physics implications of the External Reality Hypothesis (ERH) that there exists an external physical reality completely independent of us humans. I argue that with a sufficiently broad definition of mathematics, it implies the Mathematical Universe Hypothesis (MUH) that our physical world is an abstract mathematical structure. I discuss various implications of the ERH and MUH, ranging from standard physics topics like symmetries, irreducible representations, units, free parameters, randomness and initial conditions to broader issues like consciousness, parallel universes and Godel incompleteness. I hypothesize that only computable and decidable (in Godel's sense) structures exist, which alleviates the cosmological measure problem and help explain why our physical laws appear so simple. I also comment on the intimate relation between mathematical structures, computations, simulations and physical systems.Comment: Replaced to match accepted Found. Phys. version, 31 pages, 5 figs; more details at http://space.mit.edu/home/tegmark/toe.htm
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