12,472 research outputs found

    New distinguished classes of spectral spaces: a survey

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    In the present survey paper, we present several new classes of Hochster's spectral spaces "occurring in nature", actually in multiplicative ideal theory, and not linked to or realized in an explicit way by prime spectra of rings. The general setting is the space of the semistar operations (of finite type), endowed with a Zariski-like topology, which turns out to be a natural topological extension of the space of the overrings of an integral domain, endowed with a topology introduced by Zariski. One of the key tool is a recent characterization of spectral spaces, based on the ultrafilter topology, given in a paper by C. Finocchiaro in Comm. Algebra 2014. Several applications are also discussed

    Phonon Properties of Knbo3 and Ktao3 from First-Principles Calculations

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    The frequencies of transverse-optical Γ\Gamma phonons in KNbO3_3 and KTaO3_3 are calculated in the frozen-phonon scheme making use of the full-potential linearized muffin-tin orbital method. The calculated frequencies in the cubic phase of KNbO3_3 and in the tetragonal ferroelectric phase are in good agreement with experimental data. For KTaO3_3, the effect of lattice volume was found to be substantial on the frequency of the soft mode, but rather small on the relative displacement patterns of atoms in all three modes of the T1uT_{1u} symmetry. The TO frequencies in KTaO3_3 are found to be of the order of, but somehow higher than, the corresponding frequencies in cubic KNbO3_3.Comment: 8 pages + 1 LaTeX figure, Revtex 3.0, SISSA-CM-94-00

    Weak lensing mass reconstruction of the interacting cluster 1E0657-558: Direct evidence for the existence of dark matter

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    We present a weak lensing mass reconstruction of the interacting cluster 1E0657-558 in which we detect both the main cluster and a sub-cluster. The sub-cluster is identified as a smaller cluster which has just undergone initial in-fall and pass-through of the primary cluster, and has been previously identified in both optical surveys and X-ray studies. The X-ray gas has been separated from the galaxies by ram-pressure stripping during the pass-through. The detected mass peak is located between the X-ray peak and galaxy concentration, although the position is consistent with the galaxy centroid within the errors of the mass reconstruction. We find that the mass peak for the main cluster is in good spatial agreement with the cluster galaxies and offset from the X-ray halo at 3.4 sigma significance, and determine that the mass-to-light ratios of the two components are consistent with those of relaxed clusters. The observed offsets of the lensing mass peaks from the peaks of the dominant visible mass component (the X-ray gas) directly demonstrate the presence, and dominance, of dark matter in this cluster. This proof of the dark matter existence holds true even under the assumption of modified Newtonian gravity (MOND); from the observed gravitational shear to optical light ratios and mass peak - X-ray gas offsets, the dark matter component in a MOND regime has a total mass which is at least equal to the baryonic mass of the system.Comment: 8 pages, 4 figure, accepted by Ap

    On the existence of sure profits via flash strategies

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    © Applied Probability Trust 2019. We introduce and study the notion of sure profits via flash strategies, consisting of a high-frequency limit of buy-and-hold trading strategies. In a fully general setting, without imposing any semimartingale restriction, we prove that there are no sure profits via flash strategies if and only if asset prices do not exhibit predictable jumps. This result relies on the general theory of processes and provides the most general formulation of the well-known fact that, in an arbitrage-free financial market, asset prices (including dividends) should not exhibit jumps of a predictable direction or magnitude at predictable times. We furthermore show that any price process is always right-continuous in the absence of sure profits. Our results are robust under small transaction costs and imply that, under minimal assumptions, price changes occurring at scheduled dates should only be due to unanticipated information releases

    OPEN NETWORK FOR LOCAL SELF SUSTAINABILITY, BOOSTING BIOREGIONAL DEVELOPMENT THROUGH AN OPEN DATA SHARING SYSTEM

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    Abstract. The paper presents an online geodatabase currently under development. Its name is Open NETwork for Local Self Sustainability and the website address is www.oloss.net.The goal of this platform is to publish and share information about production and consumption chain oriented towards the use of locally available resources. To this end, it provides an open standard of supply chains georeferenced representation, and the ability to georefer data generally used in the context of life cycle analysis of products and services. This standard has the purpose of representing production and consumption chains in the form of Impact Geographies (IGs). This database may provide public administration centers, research centers, NGOs, planners and designers with information useful to develop projects geared towards the optimal use of local resources, consistent with the bioregional development paradigm (Sale, 1985) (Scudo, 2016). The bioregional approach promotes trans-scalar regional supply and demand chains where food and energy are grown, produced, sold and consumed within a certain territorial unit.</p

    Thermodynamic Scaling of the Viscosity of Van Der Waals, H-Bonded, and Ionic Liquids

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    Viscosities and their temperature, T, and volume, V, dependences are reported for 7 molecular liquids and polymers. In combination with literature viscosity data for 5 other liquids, we show that the superpositioning of relaxation times for various glass-forming materials when expressed as a function of TV^g, where the exponent g is a material constant, can be extended to the viscosity. The latter is usually measured to higher temperatures than the corresponding relaxation times, demonstrating the validity of the thermodynamic scaling throughout the supercooled and higher T regimes. The value of g for a given liquid principally reflects the magnitude of the intermolecular forces (e.g., steepness of the repulsive potential); thus, we find decreasing g in going from van der Waals fluids to ionic liquids. For strongly H-bonded materials, such as low molecular weight polypropylene glycol and water, the superpositioning fails, due to the non-trivial change of chemical structure (degree of H-bonding) with thermodynamic conditions.Comment: 16 pages 7 figure

    Photometry and Photometric Redshifts of Faint Galaxies in the Hubble Deep Field South NICMOS Field

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    We present a catalog of photometry and photometric redshifts of 335 faint objects in the HDF-S NICMOS field. The analysis is based on (1) infrared images obtained with the Hubble Space Telescope (HST) using the Near Infrared Camera and Multi-Object Spectrograph (NICMOS) with the F110W, F160W, and F222M filters, (2) an optical image obtained with HST using the Space Telescope Imaging Spectrograph (STIS) with no filter, and (3) optical images obtained with the European Southern Observatory (ESO) Very Large Telescope (VLT) with U, B, V, R, and I filters. The primary utility of the catalog of photometric redshifts is as a survey of faint galaxies detected in the NICMOS F160W and F222M images. The sensitivity of the survey varies significantly with position, reaching a limiting depth of AB(16,000) ~ 28.7 and covering 1.01 arcmin^2 to AB(16,000) = 27 and 1.05 arcmin^2 to AB(16,000) = 26.5. The catalog of photometric redshifts identifies 21 galaxies (or 6% of the total) of redshift z > 5, 8 galaxies (or 2% of the total) of redshift z > 10, and 11 galaxies (or 3% of the total) of best-fit spectral type E/S0, of which 5 galaxies (or 1% of the total) are of redshift z > 1.Comment: 33 pages, 10 figures, accepted for publication in the Astrophysical Journal, August 1, 2000 issu

    Long-term placement of continuous popliteal nerve block catheter for management of a wounded patient in a combat field environment: A case report

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    Continuous peripheral nerve block is a relevant part of multimodal treatment of postoperative pain. In this context the continuous popliteal nerve block is described as an option for postoperative pain management for surgical procedures on the leg, and particularly on the ankle and foot. We applied continuous popliteal nerve block for different types of anesthesia and postoperative pain management via the same catheter. No clear evidence of this specific use has been described in the literature. A 38 year-old patient wounded in combat with a displaced fracture of left tibia and extensive loss of substance needed orthopedic surgeries as well as several reconstructive procedures. A continuous popliteal nerve block was applied via ultrasound-guided catheter for anesthesia at different times, and postoperative pain control for all surgical procedures. The continuous popliteal nerve block and its long-term positioning, of non-common evidence in literature, was utilized to treat a poly-traumatized patient, thereby avoiding repeated general anesthesia and opioid use and their adverse effects. This technique, within a complicated combat field environment, was demonstrated to be clinically effective with high patient satisfaction
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