2,039 research outputs found

    Dense Molecular Filaments Feeding a Starburst: ALMA Maps of CO(3-2) in Henize 2-10

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    We present ALMA CO(3-2) observations at 0.3 arcsec resolution of He2-10, a starburst dwarf galaxy and possible high-z galaxy analogue. The warm dense gas traced by CO(3--2) is found in clumpy filaments that are kinematically and spatially distinct. The filaments have no preferred orientation or direction; this may indicate that the galaxy is not evolving into a disk galaxy. Filaments appear to be feeding the active starburst; the velocity field in one filament suggests acceleration onto an embedded star cluster. The relative strengths of CO(3-2) and radio continuum vary strongly on decaparsec scales in the starburst. There is no CO(3--2) clump coincident with the non-thermal radio source that has been suggested to be an AGN, nor unusual kinematics. The kinematics of the molecular gas show significant activity apparently unrelated to the current starburst. The longest filament, east of the starburst, has a pronounced shear of FWHM ∼40\sim40~\kms\ across its ∼\sim50~pc width over its entire ≈0.5\approx 0.5 kpc length. The cause of the shear is not clear. This filament is close in projection to a `dynamically distinct' CO feature previously seen in CO(1--0). The most complex region and the most highly disturbed gas velocities are in a region 200~pc south of the starburst. The CO(3--2) emission there reveals a molecular outflow, of linewidth FWZI ∼\sim 120-140 \kms, requiring an energy ≳1053 erg/s\gtrsim 10^{53} \rm~ erg/s. There is at present {\it no} candidate for the driving source of this outflow.Comment: This was revised 31 October to correct some typos and to replace Figure

    Transformations of Logic Programs on Infinite Lists

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    We consider an extension of logic programs, called \omega-programs, that can be used to define predicates over infinite lists. \omega-programs allow us to specify properties of the infinite behavior of reactive systems and, in general, properties of infinite sequences of events. The semantics of \omega-programs is an extension of the perfect model semantics. We present variants of the familiar unfold/fold rules which can be used for transforming \omega-programs. We show that these new rules are correct, that is, their application preserves the perfect model semantics. Then we outline a general methodology based on program transformation for verifying properties of \omega-programs. We demonstrate the power of our transformation-based verification methodology by proving some properties of Buechi automata and \omega-regular languages.Comment: 37 pages, including the appendix with proofs. This is an extended version of a paper published in Theory and Practice of Logic Programming, see belo

    Electrodeposited inorganic separators for alkaline batteries

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    Coating electrodes of silver-cadmium cells with thermostable electrodeposits of calcium hydroxide or magnesium hydroxide reduces silver migration and increases cell life. Absence of organic matter enables assembled cells to be sterilized without oxidation of the material of the separators

    A Bayesian Networks Approach to Operational Risk

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    A system for Operational Risk management based on the computational paradigm of Bayesian Networks is presented. The algorithm allows the construction of a Bayesian Network targeted for each bank using only internal loss data, and takes into account in a simple and realistic way the correlations among different processes of the bank. The internal losses are averaged over a variable time horizon, so that the correlations at different times are removed, while the correlations at the same time are kept: the averaged losses are thus suitable to perform the learning of the network topology and parameters. The algorithm has been validated on synthetic time series. It should be stressed that the practical implementation of the proposed algorithm has a small impact on the organizational structure of a bank and requires an investment in human resources limited to the computational area

    Identification and Characterization of Two Labeled Intermediates in the Biosynthesis of Rat Thyroglobulin

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    Abstract Two protein components related to 19 S thyroglobulin and labeled at early times during its biosynthesis have been isolated and characterized. A 3–8 S fraction was prepared from the soluble extract of rat thyroid glands incubated in vitro with radioactive amino acids ([3H]leucine and [14C]isoleucine) or carbohydrates ([3H]- or [14C]mannose and [3H]- or [14C]galactose) or both. From this fraction three components were purified. Two of them, homogeneous by ultracentrifugal and electrophoretic criteria, had sedimentation rates of 6 S and 7 S and molecular weights close to 112,000 and 186,000, respectively. The molar ratios of labeled leucine to isoleucine incorporated into the 6 S and 7 S fractions were the same as those found in 19 S thyroglobulin and in its 12 S subunit. Both the 6 S and 7 S protein units were quantitatively precipitated by anti-rat thyroglobulin antibodies. Double labeling with [3H]leucine and 14C-carbohydrates demonstrated that mannose is present in the fully assembled 19 S and 12 S proteins as well as on the slower sedimenting 6 S and 7 S units, whereas galactose is incorporated only after the formation of the fully assembled stable thyroglobulin molecule. It is concluded that the 6 S and 7 S labeled proteins, which contain only part of the carbohydrate moiety of thyroglobulin, participate in the structure of newly formed unstable 19 S molecules and may represent intermediates during the assembly process of the elementary polypeptide chains of thyroglobulin

    Effects of Acute Cadmium Exposure on the Pituitary Gland of Podarcis sicula

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    Reptiles are rarely used in studies on the possible toxic effects of heavy metals even if they are susceptible to the accumulation of persistent pollution due also to their presence in a variety of habitats. Cadmium is a heavy metal, a significant environmental pollutant and an endocrine disruptor. Therefore the aim of this study was to analyze the cytotoxic effects of cadmium on the pituitary gland of the lizard Podarcis sicula after an acute exposure to this metal. The analysis were carried out after 2, 7 and 16 days following the intraperitoneal injection of a single and massive dose of cadmium chloride. The pituitary glands were analyzed by histological and immuhistochemical stains. Besides cadmium accumulation in brain was measured by atomic absorption spectrometry. Cadmium concentration increased in lizard brain lightly after 2 days and widely after 16 days. The tissue of the pituitary gland appeared slightly atrophied in a few areas only at 7 and 16 days after treatment. Moreover an increase in intensity of immunostaining and occurrence of some adenohypophyseal cells was revealed respect to control lizards. This evidence suggests an inhibitory effect of cadmium on the normal hormonal secretion. Evidently an acute cadmium exposure in P. sicula involves the accumulation of this metal in the brain but also the alteration of the normal endocrine function of the pituitary gland

    Five Days at India House

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    A thesis submitted in partial fulfillment of the requirements for the degree of Master of Fine Arts in Creative Writing at Virginia Commonwealth University

    Entangled States Are Harder to Transfer than Product States

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    The distribution of entangled states is a key task of utmost importance for many quantum information processing protocols. A commonly adopted setup for distributing quantum states envisages the creation of the state in one location, which is then sent to (possibly different) distant receivers through some quantum channels. While it is undoubted and, perhaps, intuitively expected that the distribution of entangled quantum states is less efficient than that of product states, a thorough quantification of this inefficiency (namely, of the difference between the quantum-state transfer fidelity for entangled and factorized states) has not been performed. To this end, in this work, we consider n-independent amplitude-damping channels, acting in parallel, i.e., each, locally, on one part of an n-qubit state. We derive exact analytical results for the fidelity decrease, with respect to the case of product states, in the presence of entanglement in the initial state, for up to four qubits. Interestingly, we find that genuine multipartite entanglement has a more detrimental effect on the fidelity than two-qubit entanglement. Our results hint at the fact that, for larger n-qubit states, the difference in the average fidelity between product and entangled states increases with increasing single-qubit fidelity, thus making the latter a less trustworthy figure of merit
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