Graphene antidot lattice waveguides
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Gunst, Tue; Markussen, Troels
2012-01-01
We introduce graphene antidot lattice waveguides: nanostructured graphene where a region of pristine graphene is sandwiched between regions of graphene antidot lattices. The band gaps in the surrounding antidot lattices enable localized states to emerge in the central waveguide region. We model...... the waveguides via a position-dependent mass term in the Dirac approximation of graphene and arrive at analytical results for the dispersion relation and spinor eigenstates of the localized waveguide modes. To include atomistic details we also use a tight-binding model, which is in excellent agreement...... with the analytical results. The waveguides resemble graphene nanoribbons, but without the particular properties of ribbons that emerge due to the details of the edge. We show that electrons can be guided through kinks without additional resistance and that transport through the waveguides is robust against...
Density functional study of graphene antidot lattices: Roles of geometrical relaxation and spin
DEFF Research Database (Denmark)
Fürst, Joachim Alexander; Pedersen, Thomas Garm; Brandbyge, Mads
2009-01-01
Graphene sheets with regular perforations, dubbed as antidot lattices, have theoretically been predicted to have a number of interesting properties. Their recent experimental realization with lattice constants below 100 nanometers stresses the urgency of a thorough understanding of their electronic...
Graphene on graphene antidot lattices
DEFF Research Database (Denmark)
Gregersen, Søren Schou; Pedersen, Jesper Goor; Power, Stephen
2015-01-01
Graphene bilayer systems are known to exhibit a band gap when the layer symmetry is broken by applying a perpendicular electric field. The resulting band structure resembles that of a conventional semiconductor with a parabolic dispersion. Here, we introduce a bilayer graphene heterostructure......, where single-layer graphene is placed on top of another layer of graphene with a regular lattice of antidots. We dub this class of graphene systems GOAL: graphene on graphene antidot lattice. By varying the structure geometry, band-structure engineering can be performed to obtain linearly dispersing...
Graphene antidot lattice transport measurements
DEFF Research Database (Denmark)
Mackenzie, David; Cagliani, Alberto; Gammelgaard, Lene
2017-01-01
We investigate graphene devices patterned with a narrow band of holes perpendicular to the current flow, a few-row graphene antidot lattice (FR-GAL). Theoretical reports suggest that a FR-GAL can have a bandgap with a relatively small reduction of the transmission compared to what is typical...... for antidot arrays devices. Graphene devices were fabricated using 100 keV electron beam lithography (EBL) for nanopatterning as well as for defining electrical contacts. Patterns with hole diameter and neck widths of order 30 nm were produced, which is the highest reported pattern density of antidot lattices...... in graphene reported defined by EBL. Electrical measurements showed that devices with one and five rows exhibited field effect mobility of ∼100 cm2/Vs, while a larger number of rows, around 40, led to a significant reduction of field effect mobility (
Electronic properties of graphene antidot lattices
International Nuclear Information System (INIS)
Fuerst, J A; Brandbyge, M; Jauho, A-P; Pedersen, J G; Mortensen, N A; Flindt, C; Pedersen, T G
2009-01-01
Graphene antidot lattices constitute a novel class of nano-engineered graphene devices with controllable electronic and optical properties. An antidot lattice consists of a periodic array of holes that causes a band gap to open up around the Fermi level, turning graphene from a semimetal into a semiconductor. We calculate the electronic band structure of graphene antidot lattices using three numerical approaches with different levels of computational complexity, efficiency and accuracy. Fast finite-element solutions of the Dirac equation capture qualitative features of the band structure, while full tight-binding calculations and density functional theory (DFT) are necessary for more reliable predictions of the band structure. We compare the three computational approaches and investigate the role of hydrogen passivation within our DFT scheme.
Screening in graphene antidot lattices
DEFF Research Database (Denmark)
Schultz, Marco Haller; Jauho, A. P.; Pedersen, T. G.
2011-01-01
We compute the dynamical polarization function for a graphene antidot lattice in the random-phase approximation. The computed polarization functions display a much more complicated structure than what is found for pristine graphene (even when evaluated beyond the Dirac-cone approximation...... the plasmon dispersion law and find an approximate square-root dependence with a suppressed plasmon frequency as compared to doped graphene. The plasmon dispersion is nearly isotropic and the developed approximation schemes agree well with the full calculation....
Spectral Gaps in Graphene Antidot Lattices
DEFF Research Database (Denmark)
Barbaroux, Jean-Marie; Cornean, Decebal Horia; Stockmeyer, Edgardo
2017-01-01
We consider the gap creation problem in an antidot graphene lattice, i.e. a sheet of graphene with periodically distributed obstacles. We prove several spectral results concerning the size of the gap and its dependence on different natural parameters related to the antidot lattice....
Electronic properties of graphene antidot lattices
DEFF Research Database (Denmark)
Fürst, Joachim Alexander; Pedersen, Jesper Goor; Flindt, C.
2009-01-01
Graphene antidot lattices constitute a novel class of nano-engineered graphene devices with controllable electronic and optical properties. An antidot lattice consists of a periodic array of holes that causes a band gap to open up around the Fermi level, turning graphene from a semimetal...... into a semiconductor. We calculate the electronic band structure of graphene antidot lattices using three numerical approaches with different levels of computational complexity, efficiency and accuracy. Fast finite-element solutions of the Dirac equation capture qualitative features of the band structure, while full...
Optical properties of graphene antidot lattices
DEFF Research Database (Denmark)
Pedersen, Thomas Garm; Flindt, Christian; Pedersen, Jesper Goor
2008-01-01
Undoped graphene is semimetallic and thus not suitable for many electronic and optoelectronic applications requiring gapped semiconductor materials. However, a periodic array of holes (antidot lattice) renders graphene semiconducting with a controllable band gap. Using atomistic modeling, we...
Thermoelectric properties of finite graphene antidot lattices
DEFF Research Database (Denmark)
Gunst, Tue; Markussen, Troels; Jauho, Antti-Pekka
2011-01-01
We present calculations of the electronic and thermal transport properties of graphene antidot lattices with a finite length along the transport direction. The calculations are based on the π-tight-binding model and the Brenner potential. We show that both electronic and thermal transport...
Spin qubits in antidot lattices
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Flindt, Christian; Mortensen, Niels Asger
2008-01-01
We suggest and study designed defects in an otherwise periodic potential modulation of a two-dimensional electron gas as an alternative approach to electron spin based quantum information processing in the solid-state using conventional gate-defined quantum dots. We calculate the band structure a...... electron transport between distant defect states in the lattice, and for a tunnel coupling of neighboring defect states with corresponding electrostatically controllable exchange coupling between different electron spins.......We suggest and study designed defects in an otherwise periodic potential modulation of a two-dimensional electron gas as an alternative approach to electron spin based quantum information processing in the solid-state using conventional gate-defined quantum dots. We calculate the band structure...
Electronic properties of disordered graphene antidot lattices
DEFF Research Database (Denmark)
Yuan, Shengjun; Roldán, Rafael; Jauho, Antti-Pekka
2013-01-01
Regular nanoscale perforations in graphene (graphene antidot lattices, GALs) are known to lead to a gap in the energy spectrum, thereby paving a possible way towards many applications. This theoretical prediction relies on a perfect placement of identical perforations, a situation not likely...... for solving the time-dependent Schro¨dinger equation in a tight-binding representation of the graphene sheet [Yuan et al., Phys. Rev. B 82, 115448 (2010)], which allows us to consider GALs consisting of 6400 × 6400 carbon atoms. The central conclusion for all kinds of disorder is that the gaps found...
Electronic transport in disordered graphene antidot lattice devices
DEFF Research Database (Denmark)
Power, Stephen; Jauho, Antti-Pekka
2014-01-01
Nanostructuring of graphene is in part motivated by the requirement to open a gap in the electronic band structure. In particular, a periodically perforated graphene sheet in the form of an antidot lattice may have such a gap. Such systems have been investigated with a view towards application...... in transistor or waveguiding devices. The desired properties have been predicted for atomically precise systems, but fabrication methods will introduce significant levels of disorder in the shape, position and edge configurations of individual antidots. We calculate the electronic transport properties of a wide...... range of finite graphene antidot devices to determine the effect of such disorders on their performance. Modest geometric disorder is seen to have a detrimental effect on devices containing small, tightly packed antidots, which have optimal performance in pristine lattices. Larger antidots display...
Anomalous giant piezoresistance in AlAs 2D electron systems with antidot lattices.
Gunawan, O; Gokmen, T; Shkolnikov, Y P; De Poortere, E P; Shayegan, M
2008-01-25
An AlAs two-dimensional electron system patterned with an antidot lattice exhibits a giant piezoresistance effect at low temperatures, with a sign opposite to the piezoresistance observed in the unpatterned region. We suggest that the origin of this anomalous giant piezoresistance is the nonuniform strain in the antidot lattice and the exclusion of electrons occupying the two conduction-band valleys from different regions of the sample. This is analogous to the well-known giant magnetoresistance effect, with valley playing the role of spin and strain the role of magnetic field.
Graphene antidot lattices: Designed defects and spin qubits
DEFF Research Database (Denmark)
Pedersen, Thomas; Flindt, Christian; Pedersen, Jesper Goor
2008-01-01
similar phenomenology, but within a much more favorable energy scale, a consequence of the Dirac fermion nature of the states around the Fermi level. Further, by leaving out some of the holes one can create defect states, or pairs of coupled defect states, which can function as hosts for electron spin......Antidot lattices, defined on a two-dimensional electron gas at a semiconductor heterostructure, are a well-studied class of man-made structures with intriguing physical properties. We point out that a closely related system, graphene sheets with regularly spaced holes ("antidots"), should display...... qubits. We present a detailed study of the energetics of periodic graphene antidot lattices, analyze the level structure of a single defect, calculate the exchange coupling between a pair of spin qubits, and identify possible avenues for further developments....
Clar sextets in square graphene antidot lattices
DEFF Research Database (Denmark)
Petersen, Rene; Pedersen, Thomas Garm; Jauho, Antti-Pekka
2011-01-01
A periodic array of holes transforms graphene from a semimetal into a semiconductor with a band gap tuneable by varying the parameters of the lattice. In earlier work only hexagonal lattices have been treated. Using atomistic models we here investigate the size of the band gap of a square lattice...
All optical detection of picosecond spin-wave dynamics in 2D annular antidot lattice
Porwal, Nikita; Mondal, Sucheta; Choudhury, Samiran; De, Anulekha; Sinha, Jaivardhan; Barman, Anjan; Datta, Prasanta Kumar
2018-02-01
Novel magnetic structures with precisely controlled dimensions and shapes at the nanoscale have potential applications in spin logic, spintronics and other spin-based communication devices. We report the fabrication of 2D bi-structure magnonic crystal in the form of embedded nanodots in a periodic Ni80Fe20 antidot lattice structure (annular antidot) by focused ion-beam lithography. The spin-wave spectra of the annular antidot sample, studied for the first time by a time-resolved magneto-optic Kerr effect microscopy show a remarkable variation with bias field, which is important for the above device applications. The optically induced spin-wave spectra show multiple modes in the frequency range 14.7 GHz-3.5 GHz due to collective interactions between the dots and antidots as well as the annular elements within the whole array. Numerical simulations qualitatively reproduce the experimental results, and simulated mode profiles reveal the spatial distribution of the spin-wave modes and internal magnetic fields responsible for these observations. It is observed that the internal field strength increases by about 200 Oe inside each dot embedded within the hole of annular antidot lattice as compared to pure antidot lattice and pure dot lattice. The stray field for the annular antidot lattice is found to be significant (0.8 kOe) as opposed to the negligible values of the same for the pure dot lattice and pure antidot lattice. Our findings open up new possibilities for development of novel artificial crystals.
Periodic Arrays of Phosphorene Nanopores as Antidot Lattices with Tunable Properties.
Cupo, Andrew; Masih Das, Paul; Chien, Chen-Chi; Danda, Gopinath; Kharche, Neerav; Tristant, Damien; Drndić, Marija; Meunier, Vincent
2017-07-25
A tunable band gap in phosphorene extends its applicability in nanoelectronic and optoelectronic applications. Here, we propose to tune the band gap in phosphorene by patterning antidot lattices, which are periodic arrays of holes or nanopores etched in the material, and by exploiting quantum confinement in the corresponding nanoconstrictions. We fabricated antidot lattices with radii down to 13 nm in few-layer black phosphorus flakes protected by an oxide layer and observed suppression of the in-plane phonon modes relative to the unmodified material via Raman spectroscopy. In contrast to graphene antidots, the Raman peak positions in few-layer BP antidots are unchanged, in agreement with predicted power spectra. We also use DFT calculations to predict the electronic properties of phosphorene antidot lattices and observe a band gap scaling consistent with quantum confinement effects. Deviations are attributed primarily to self-passivating edge morphologies, where each phosphorus atom has the same number of bonds per atom as the pristine material so that no dopants can saturate dangling bonds. Quantum confinement is stronger for the zigzag edge nanoconstrictions between the holes as compared to those with armchair edges, resulting in a roughly bimodal band gap distribution. Interestingly, in two of the antidot structures an unreported self-passivating reconstruction of the zigzag edge endows the systems with a metallic component. The experimental demonstration of antidots and the theoretical results provide motivation to further scale down nanofabrication of antidots in the few-nanometer size regime, where quantum confinement is particularly important.
Designed defects in 2D antidot lattices for quantum information processing
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Flindt, Christian; Mortensen, Niels Asger
2008-01-01
We propose a new physical implementation of spin qubits for quantum information processing, namely defect states in antidot lattices defined in the two-dimensional electron gas (2DEG) at a semiconductor heterostructure. Calculations of the band structure of a periodic antidot lattice are presente....... We find results reminiscent of double quantum dot structures, indicating that the suggested structure is a feasible physical implementation of spin qubits....
Energy Technology Data Exchange (ETDEWEB)
Gubbiotti, G.; Tacchi, S. [Istituto Officina dei Materiali del Consiglio Nazionale delle Ricerche (IOM-CNR), Sede di Perugia, c/o Dipartimento di Fisica e Geologia, Via A. Pascoli, I-06123 Perugia (Italy); Montoncello, F.; Giovannini, L. [Dipartimento di Fisica e Scienze della Terra, Università di Ferrara, Via G. Saragat 1, I-44122 Ferrara (Italy); Madami, M.; Carlotti, G. [Dipartimento di Fisica e Geologia, Università di Perugia, Via A. Pascoli, I-06123 Perugia (Italy); Ding, J.; Adeyeye, A. O. [Information Storage Materials Laboratory, Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117576 (Singapore)
2015-06-29
The Brillouin light scattering technique has been exploited to study the angle-resolved spin wave band diagrams of squared Permalloy antidot lattice. Frequency dispersion of spin waves has been measured for a set of fixed wave vector magnitudes, while varying the wave vector in-plane orientation with respect to the applied magnetic field. The magnonic band gap between the two most dispersive modes exhibits a minimum value at an angular position, which exclusively depends on the product between the selected wave vector magnitude and the lattice constant of the array. The experimental data are in very good agreement with predictions obtained by dynamical matrix method calculations. The presented results are relevant for magnonic devices where the antidot lattice, acting as a diffraction grating, is exploited to achieve multidirectional spin wave emission.
Hofstadter butterflies and magnetically induced band-gap quenching in graphene antidot lattices
DEFF Research Database (Denmark)
Pedersen, Jesper Goor; Pedersen, Thomas Garm
2013-01-01
We study graphene antidot lattices (GALs) in magnetic fields. Using a tight-binding model and a recursive Green's function technique that we extend to deal with periodic structures, we calculate Hofstadter butterflies of GALs. We compare the results to those obtained in a simpler gapped graphene...... model. A crucial difference emerges in the behavior of the lowest Landau level, which in a gapped graphene model is independent of magnetic field. In stark contrast to this picture, we find that in GALs the band gap can be completely closed by applying a magnetic field. While our numerical simulations...... can only be performed on structures much smaller than can be experimentally realized, we find that the critical magnetic field for which the gap closes can be directly related to the ratio between the cyclotron radius and the neck width of the GAL. In this way, we obtain a simple scaling law...
Energy Technology Data Exchange (ETDEWEB)
Zhdanov, E. Yu., E-mail: zhdanov@isp.nsc.ru; Pogosov, A. G.; Budantsev, M. V.; Pokhabov, D. A.; Bakarov, A. K. [Siberian Branch of the Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics (Russian Federation)
2017-01-15
The magnetoresistance of suspended semiconductor nanostructures with a two-dimensional electron gas structured by periodic square antidot lattices is studied. It is shown that the ballistic regime of electron transport is retained after detaching the sample from the substrate. Direct comparative analysis of commensurability oscillations of magnetoresistance and their temperature dependences in samples before and after suspension is performed. It is found that the temperature dependences are almost identical for non-suspended and suspended samples, whereas significant differences are observed in the nonlinear regime, caused by direct current passage. Commensurability oscillations in the suspended samples are more stable with respect to exposure to direct current, which can be presumably explained by electron–electron interaction enhancement after detaching nanostructures from the high-permittivity substrate.
Xue, C.; Ge, J.-Y.; He, A.; Zharinov, V. S.; Moshchalkov, V. V.; Zhou, Y. H.; Silhanek, A. V.; Van de Vondel, J.
2017-07-01
We investigate the degeneracy of the superconducting vortex matter ground state by directly visualizing the vortex configurations in a kagome lattice of elongated antidots via scanning Hall probe microscopy. The observed vortex patterns, at specific applied magnetic fields, are in good agreement with the configurations obtained using time-dependent Ginzburg-Landau simulations. Both results indicate that the long-range interaction in this nanostructured superconductor is unable to lift the degeneracy between different vortex states and the pattern formation is mainly ruled by the nearest-neighbor interaction. This simplification makes it possible to identify a set of simple rules characterizing the vortex configurations. We demonstrate that these rules can explain both the observed vortex distributions and the magnetic-field-dependent degree of degeneracy.
Energy Technology Data Exchange (ETDEWEB)
Pal, S.; Das, K.; Barman, A., E-mail: abarman@ybose.res.in [Thematic Unit of Excellence on Nanodevice Technology and Department of Condensed Matter Physics and Material Sciences, S. N. Bose National Centre for Basic Sciences, Block JD, Sector III, Salt Lake, Kolkata 700 098 (India); Klos, J. W.; Gruszecki, P.; Krawczyk, M., E-mail: krawczyk@amu.edu.pl [Faculty of Physics, A. Mickiewicz University in Poznan, Umultowska 85, 61-614 Poznań (Poland); Hellwig, O. [San Jose Research Center, HGST, a Western Digital Company, 3403 Yerba Buena Rd., San Jose, California 95135 (United States)
2014-10-20
We present an all-optical time-resolved measurement of spin wave (SW) dynamics in a series of antidot lattices based on [Co(0.75 nm)/Pd(0.9 nm)]{sub 8} multilayer (ML) systems with perpendicular magnetic anisotropy. The spectra depend significantly on the areal density of the antidots. The observed SW modes are qualitatively reproduced by the plane wave method. The interesting results found in our measurements and calculations at small lattice constants can be attributed to the increase of areal density of the shells with modified magnetic properties probably due to distortion of the regular ML structure by the Ga ion bombardment and to increased coupling between localized modes. We propose and discuss the possible mechanisms for this coupling including exchange interaction, tunnelling, and dipolar interactions.
Agrawal, Vijay Kumar; Bansal, Abhishek; Singh, Ranjeet Kumar; Kumawat, Bhanwar Lal; Mahajan, Parul
2015-02-01
Aluminum phosphide (ALP) poisoning is one of the major causes of suicidal deaths. Toxicity by ALP is caused by the liberation of phosphine gas, which rapidly causes cell hypoxia due to inhibition of oxidative phosphorylation, leading to circulatory failure. Treatment of ALP toxicity is mainly supportive as there is no specific antidote. We recently managed 7 cases of ALP poisoning with severe hemodynamic effects. Patients were treated with supportive measures including gastric lavage with diluted potassium permanganate, coconut oil and sodium-bicarbonate first person account should be avoided in a scientific paper. Intravenous magnesium sulfate, proper hemodynamic monitoring and vasopressors. Four out of 7 survived thus suggesting a role of such supportive measures in the absence of specific antidote for ALP poisoning.
Directory of Open Access Journals (Sweden)
Mohamed Salaheldeen
2018-04-01
Full Text Available In this article, the magnetic properties of hexagonally ordered antidot arrays made of Dy13Fe87 alloy are studied and compared with corresponding ones of continuous thin films with the same compositions and thicknesses, varying between 20 nm and 50 nm. Both samples, the continuous thin films and antidot arrays, were prepared by high vacuum e-beam evaporation of the alloy on the top-surface of glass and hexagonally self-ordered nanoporous alumina templates, which serve as substrates, respectively. By using a highly sensitive magneto-optical Kerr effect (MOKE and vibrating sample magnetometer (VSM measurements an interesting phenomenon has been observed, consisting in the easy magnetization axis transfer from a purely in-plane (INP magnetic anisotropy to out-of-plane (OOP magnetization. For the 30 nm film thickness we have measured the volume hysteresis loops by VSM with the easy magnetization axis lying along the OOP direction. Using magnetic force microscopy measurements (MFM, there is strong evidence to suggest that the formation of magnetic domains with OOP magnetization occurs in this sample. This phenomenon can be of high interest for the development of novel magnetic and magneto-optic perpendicular recording patterned media based on template-assisted deposition techniques.
The role of the hospital pharmacy in the storage and supply of antidotes
Directory of Open Access Journals (Sweden)
Luisa Lombardo
2013-12-01
Full Text Available Cases of poisoning have been analyzed with the aim of estimating both the incidence and the seriousness of such xenobiotic effects, the major determinant agents, and the related antidotes used in hospital departments. From 2009 to November 2012, a survey of the availability of antidotes in the emergency room services was carried out in all hospital pharmacies under the Palermo Health Authority: Policlinico Paolo Giaccone, ARNAS Civico di Cristina Benefratelli, Azienda Ospedaliera Ospedali Riuniti Villa Sofia-Cervello. Figures show that the majority of poisoning events were caused by the use/abuse of drugs, especially psychopharmaceuticals, alcohol and narcotic substances. This overdose of medical drugs and its various causes is a cause for concern and highlights the fact that this tendency has not regressed over the years. Doctors and pharmacists should raise patients’ awareness about how to use drugs correctly, and make adequate information available to all patients in order to, first, reduce the risks, and second, reduce the cost of treatment for intoxication.
Magnetic edge states and magnetotransport in graphene antidot barriers
DEFF Research Database (Denmark)
Thomsen, M. R.; Power, Stephen; Jauho, Antti-Pekka
2016-01-01
for antidots smaller than the magnetic length and demonstrate the presence of magnetic edge states, which are localized states on the periphery of the antidots due to successive reflections on the antidot edge in the presence of a magnetic field. We show that these states are robust against variations...... in lattice configuration and antidot edge chirality. Moreover, we calculate the transmittance of disordered GABs and find that magnetic edge states survive a moderate degree of disorder. Due to the long phase-coherence length in graphene and the robustness of these states, we expect magnetic edge states...
The Beauty of Lattice Perturbation Theory: the Role of Lattice Perturbation Theory in B Physics
Monahan, C. J.
2012-12-01
As new experimental data arrive from the LHC the prospect of indirectly detecting new physics through precision tests of the Standard Model grows more exciting. Precise experimental and theoretical inputs are required to test the unitarity of the CKM matrix and to search for new physics effects in rare decays. Lattice QCD calculations of non-perturbative inputs have reached a precision at the level of a few percent; in many cases aided by the use of lattice perturbation theory. This review examines the role of lattice perturbation theory in B physics calculations on the lattice in the context of two questions: how is lattice perturbation theory used in the different heavy quark formalisms implemented by the major lattice collaborations? And what role does lattice perturbation theory play in determinations of non-perturbative contributions to the physical processes at the heart of the search for new physics? Framing and addressing these questions reveals that lattice perturbation theory is a tool with a spectrum of applications in lattice B physics.
Energy Technology Data Exchange (ETDEWEB)
Ujevic, Sebastian [Universidade Federal Fluminense (EEIMVR/UFF), Volta Redonda, RJ (Brazil). Escola de Engenharia Industrial e Metalurgica de Volta Redonda; Mendoza, Michel [Universidade Federal do ABC (UFABC), Santo Andre, SP (Brazil). Centro de Ciencias Naturais e Humanas
2011-07-01
Full text. We propose numerical simulations of longitudinal magneto conductance through a finite anti dot lattice located inside an open quantum dot with a magnetic field applied perpendicular to the plane. The system is connected to reservoirs using quantum point contacts. We discuss the relationship between the longitudinal magneto conductance and the generation of transversal couplings between the induced open quantum dots in the system. The system presents longitudinal magneto conductance maps with crossovers (between transversal bands) and closings (longitudinal decoupling) of fundamental quantum states related to the open quantum dots induced by the anti dot lattice. A relationship is observed between the distribution of anti dots and the formed conductance bands, allowing a systematic follow-up of the bands as a function of the applied magnetic field and quantum point contact width. We observed a high conductance intensity (between n- and (n + 1)-quantum of conductance, n = 1; 2...) in the regions of crossover and closing of states. This suggests transversal couplings between the induced open quantum dots of the system that can be modulated by varying both the anti dots potential and the quantum point contact width. A new continuous channel (not expected) is induced by the variation of the contact width and generate Fano resonances in the conductance. These resonances can be manipulated by the applied magnetic field
Jackson, Anthony
2016-01-01
For centuries, education has been seen as an antidote to intolerance and conflict. In a world rocked by violence, much of it across cultural borders, developing students' cultural understanding has become more important than ever. In this article, Asia Society vice president Anthony Jackson discusses how two high schools in the Society's…
Magnetic edge states and magnetotransport in graphene antidot barriers
DEFF Research Database (Denmark)
Thomsen, M. R.; Power, Stephen; Jauho, Antti-Pekka
2016-01-01
in lattice configuration and antidot edge chirality. Moreover, we calculate the transmittance of disordered GABs and find that magnetic edge states survive a moderate degree of disorder. Due to the long phase-coherence length in graphene and the robustness of these states, we expect magnetic edge states...
Antidotes for acute cyanide poisoning.
Borron, Stephen W; Baud, Frederic J
2012-08-01
Cyanide poisoning can present in multiple ways, given its widespread industrial use, presence in combustion products, multiple physical forms, and chemical structures. The primary target of toxicity is mitochondrial cytochrome oxidase. The onset and severity of poisoning depend on the route, dose, physicochemical structure and other variables. Common poisoning features include dyspnea, altered respiratory patterns, abnormal vital signs, altered mental status, seizures, and lactic acidosis. Our present knowledge supports cyanide poisoning treatment based on excellent supportive care with adjunctive antidotal therapy. Multiple antidotes exist and vary in regional availability. All currently marketed antidotes appear to be effective. Antidotal mechanisms include chelation, formation of stable, less toxic complexes, methemoglobin induction, and sulfane sulfur supplementation for detoxification by endogenous rhodanese. Each antidote has advantages and disadvantages. For example, hydroxocobalamin is safer than the methemoglobin inducers in patients with smoke inhalation. Research for new, safer and more effective cyanide antidotes continues.
Magnetic properties engineering of nanopatterned cobalt antidot arrays
International Nuclear Information System (INIS)
Kaidatzis, Andreas; Niarchos, Dimitrios; Del Real, Rafael P; Vázquez, Manuel; Alvaro, Raquel; Anguita, José; García-Martín, José Miguel; Luis Palma, Juan; Escrig, Juan
2016-01-01
We report on the study of arrays of 60 nm wide cobalt antidots, nanopatterned using focused ion beam milling. Square and hexagonal symmetry arrays have been studied, with varying antidot densities and lattice constant from 150 up to 300 nm. We find a strong increase of the arrays’ magnetic coercivity with respect to the unpatterned film, which is monotonic as the antidot density increases. Additionally, there is a strong influence of the array symmetry to the in-plane magnetic anisotropy: square arrays exhibit fourfold symmetry and hexagonal arrays exhibit sixfold symmetry. The above findings are corroborated by magnetic imaging and micromagnetic modeling, which show the magnetic structure of the arrays to depend strongly on the array morphology. (paper)
Magnetoconductance of a hybrid quantum ring: Effects of antidot potentials
Nammee Kim; Dae-Han Park; Heesang Kim
2016-01-01
The electronic structures and two-terminal magnetoconductance of a hybrid quantum ring are studied. The backscattering due to energy-resonance is considered in the conductance calculation. The hybrid magnetic-electric quantum ring is fabricated by applying an antidot electrostatic potential in the middle of a magnetic quantum dot. Electrons are both magnetically and electrically confined in the plane. The antidot potential repelling electrons from the center of the dot plays a critical role i...
[Theriac: medicine and antidote].
Parojcic, Dusanka; Stupar, Dragan; Mirica, Milica
2003-06-01
Theriac was an ancient multi-ingredient preparation; originating as a cure for the bites of serpents, mad dogs and wild beasts, it later became an antidote to all known poisons. The name theriac (treacle), (Greek theriake, Latin theriaca, French thériaque) was derived from the Greek for wild beast - theriakos. The first formula was created by Mithridates Vl, King of Pontus, a skillful ruler but a monster of cruelty, who, living in such a fear of being poisoned, took a great interest in toxicology. In the 1st century AD, Nero's personal physician Andromachus improved the formula of Antidotum Mithridatium by adding flesh of vipers, which was commonly believed to be the best antidote against snakebite, and by increasing the proportion of opium. It became known as Theriac of Andromachus, and contained 64 ingredients including various minerals, herbals, poisons and animal flesh and blood, all combined with honey in the form of electuarium. Later it became the cure-all medicine which, accumulating all the simples into one form, was supposed to be a universal panacea against all diseases. In the Middle Ages this famous electuarium become a patent medicine and entered official dispensaries and pharmacopoeias. The most famous and expensive Theriac in Europe was that of Venice. It was not until the l8th century that it was excluded from medical use.
Availability of antidotes in 70 hospitals in Catalonia, Spain.
Broto-Sumalla, Antoni; Rabanal-Tornero, Manel; García-Peláez, Milagros; Aguilar-Salmerón, Raquel; Fernández de Gamarra-Martínez, Edurne; Martínez-Sánchez, Lídia; Gaspar-Caro, María-José; Nogué-Xarau, Santiago
2018-01-12
Antidotes may have a relevant role in acute intoxication management and the time until its administration can influence patient survival. Study conducted by a questionnaire sent in early 2015 to 70 hospitals in Catalonia providing emergency services. Qualitative availability on each antidote was considered adequate when present in at least 80% of hospitals. The quantitative availability was considered adequate when at least 80% of hospitals had the number of units of antidote recommended. Lower complexity hospitals (level A) showed a percentage of adequate qualitative and quantitative availability of 66.7 and 42.9% respectively. In higher complexity hospitals (level B) qualitative and quantitative availability was adequate in 64.5 and 38.7% of the antidotes respectively. Data showed no differences between the different health regions as well as a positive correlation (pavailability. The availability of antidotes in Catalonia hospitals is generally low and shows differences across health regions and depending on level of complexity. Copyright © 2017 Elsevier España, S.L.U. All rights reserved.
Magnetoconductance of a hybrid quantum ring: Effects of antidot potentials
Directory of Open Access Journals (Sweden)
Nammee Kim
2016-05-01
Full Text Available The electronic structures and two-terminal magnetoconductance of a hybrid quantum ring are studied. The backscattering due to energy-resonance is considered in the conductance calculation. The hybrid magnetic-electric quantum ring is fabricated by applying an antidot electrostatic potential in the middle of a magnetic quantum dot. Electrons are both magnetically and electrically confined in the plane. The antidot potential repelling electrons from the center of the dot plays a critical role in the energy spectra and magnetoconductance. The angular momentum transition in the energy dispersion and the magnetoconductance behavior are investigated in consideration of the antidot potential variation. Results are shown using a comparison of the results of the conventional magnetic quantum dot.
Energy Technology Data Exchange (ETDEWEB)
Lee, W. S.; Johnston, S.; Moritz, B.; Lee, J.; Yi, M.; Zhou, K. J.; Schmitt, T.; Patthey, L.; Strocov, V.; Kudo, K.; Koike, Y.; van den Brink, J.; Devereaux, T. P.; Shen, Z. X.
2013-06-25
High resolution resonant inelastic x-ray scattering has been performed to reveal the role of lattice coupling in a family of quasi-1D insulating cuprates, Ca_{2+5x}Y_{2-5x}Cu_{5}O_{10}. Site-dependent low-energy excitations arising from progressive emissions of a 70 meV lattice vibrational mode are resolved for the first time, providing a direct measurement of electron-lattice coupling strength. We show that such electron-lattice coupling causes doping-dependent distortions of the Cu-O-Cu bond angle, which sets the intrachain spin exchange interactions. Our results indicate that the lattice degrees of freedom are fully integrated into the electronic behavior in low-dimensional systems.
Chemical terrorism attacks: update on antidotes.
Lawrence, David T; Kirk, Mark A
2007-05-01
There is well-founded concern that a chemical or radioactive agent will at some point be used as a weapon of terror. There are several antidotes that, if used correctly in a timely fashion, can help lessen the harm caused by these agents. This article is meant to introduce the clinician to several such agents, along with the antidotes useful in the management of exposure to these. It covers the indications, administration, and precautions for using these antidotes.
ACUTE TOXICITY STUDIES AND ANTIDOTAL THERAPY OF ...
African Journals Online (AJOL)
ACUTE TOXICITY STUDIES AND ANTIDOTAL THERAPY OF ETHANOL EXTRACT OF JATROPHA CURCAS SEEDS IN EXPERIMENTAL ANIMALS. ... with the aim of investigating the toxicity of the ethanol seed extract of JC in rats, mice, and chicks; and also to use conventional antidotes to treat intoxication in rats due to ...
Energy Technology Data Exchange (ETDEWEB)
Rodríguez-Suárez, R.L., E-mail: rrodriguez@fis.puc.cl [Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860 Casilla 306, Santiago (Chile); Palma, J.L.; Burgos, E.O. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Michea, S. [Facultad de Física, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860 Casilla 306, Santiago (Chile); Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Escrig, J.; Denardin, J.C. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Aliaga, C. [Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Facultad de Química y Biología, Universidad de Santiago de Chile, Casilla 40, Correo 33, Santiago (Chile)
2014-01-15
The magnetic properties of Ni{sub 80}Fe{sub 20} antidot arrays with hole diameters of 18 and 70 nm fabricated by a template-assisted method were investigated using the ferromagnetic resonance technique. Tuning the antidot arrays by changing the hole diameter enables control on the angular dependence of the ferromagnetic resonance field. The scanning electron microscope images reveal a quite regular hexagonal arrangement of the pores, however the angular dependence of the resonance field do not exhibit the six-fold symmetry expected for this symmetry. Micromagnetic simulations performed on a perfect hexagonal lattice, when compared with those made on our real system taken from the scanning microscope images, reveal that the presence of defects in the antidot lattice affects the ferromagnetic resonance field symmetry. - Highlights: • We use the FMR technique to investigate the magnetic properties of Py antidots. • We studied the effect of pore diameter on FMR angular measurement. • FMR field does not exhibit the six-fold symmetry. • For all angular positions there are two resonance modes always present. • Micromagnetic simulations agree with the experimental results with defects.
ANTIDotE: anti-tick vaccines to prevent tick-borne diseases in Europe
Sprong, Hein; Trentelman, Jos; Seemann, Ingar; Grubhoffer, Libor; Rego, Ryan O. M.; Hajdušek, Ondřej; Kopáček, Petr; Šíma, Radek; Nijhof, Ard M.; Anguita, Juan; Winter, Peter; Rotter, Bjorn; Havlíková, Sabina; Klempa, Boris; Schetters, Theo P.; Hovius, Joppe W. R.
2014-01-01
Ixodes ricinus transmits bacterial, protozoal and viral pathogens, causing disease and forming an increasing health concern in Europe. ANTIDotE is an European Commission funded consortium of seven institutes, which aims to identify and characterize tick proteins involved in feeding and pathogen
Antidotes for alcohol and glycol toxicity: translating mechanisms into treatments.
McMartin, K E
2010-09-01
Translational toxicology can be defined as the movement of potential antidotes for the treatment of poisonings from basic mechanistic research to the marketplace. Because poisonings are infrequent, the clinical development of antidotes is fraught with trials and tribulations. Academic scientists often conduct basic mechanistic work with antidotes but are infrequently involved in further drug development. This article presents the development of 4-methylpyrazole (4MP) (fomepizole) as an antidote against toxic alcohol poisonings, particularly by methanol and ethylene glycol (EG).
Role of lattice inhomogeneities on the electronic properties of selenium deficient Bi2Se3
Tayal, Akhil; Kumar, Devendra; Lakhani, Archana
2017-11-01
Inter-layer coupling is widely considered to play a crucial role in tuning electronic properties of 3D topological insulators. The aim of this study is to evaluate the role of crystallographic defects on inter-layer coupling in the Se deficient Bi2Se3 (0 0 3) crystal using extended x-ray absorption fine structure spectroscopy (EXAFS) technique. EXAFS measurements at Se-K and Bi-L3 edges reveal distinct local geometry around these atomic sites. It has been observed that short inter-layer Bi-Se and Se-Se bonds emerge in the sample. This additional structural motif coexists with the conventional crystallographic arrangement. Within the quintuple layer Bi-Se bonds are preserved with slight compression in intra-planer Bi-Bi and Se-Se distance and overall reduction in c/a ratio. These findings suggest formation of deformed lattice region, localized and dispersed inhomogeneously within the sample. Such inhomogeneities have also resulted in interesting transport properties such as quantum Hall effect (QHE), large linear magnetoresistance and π-Berry phase in Shubnikov-de Haas (SdH) oscillations of bulk crystals. Detailed analyses of magnetotransport measurements suggest that tuning of inter-layer coupling by local lattice deformation is the key factor for unusual transport properties. Role of axial strain, and stacking faults generated due to defects and charged Se vacancies are discussed to understand the observed electronic properties.
Histopathological and Biochemical evaluations of the antidotal ...
African Journals Online (AJOL)
Objective: The study was designed to investigate the effects of continuous exposure of dichlorvos (DDVP) on hepatic function and hepatic histomorphology, with the possible antidotal efficacy of Nigella sativa oil (NSO). Methods: Twenty four Wistar rats were randomly divided into four groups, with each group comprising of ...
Thermoelectric properties of one-dimensional graphene antidot arrays
International Nuclear Information System (INIS)
Yan, Yonghong; Liang, Qi-Feng; Zhao, Hui; Wu, Chang-Qin; Li, Baowen
2012-01-01
We investigate the thermoelectric properties of one-dimensional (1D) graphene antidot arrays by nonequilibrium Green's function method. We show that by introducing antidots to the pristine graphene nanoribbon the thermal conductance can be reduced greatly while keeping the power factor still high, thus leading to an enhanced thermoelectric figure of merit (ZT). Our numerical results indicate that ZT values of 1D antidot graphene arrays can be up to unity, which means the 1D graphene antidot arrays may be promising for thermoelectric applications. -- Highlights: ► We study thermoelectric properties of one-dimensional (1D) graphene antidot arrays. ► Thermoelectric figure of merit (ZT) of 1D antidot arrays can exceed unity. ► ZT of 1D antidot arrays is larger than that of two-dimensional arrays.
Potential role for MATER in cytoplasmic lattice formation in murine oocytes.
Directory of Open Access Journals (Sweden)
Boram Kim
2010-09-01
Full Text Available Mater and Padi6 are maternal effect genes that are first expressed during oocyte growth and are required for embryonic development beyond the two-cell stage in the mouse. We have recently found that PADI6 localizes to, and is required for the formation of, abundant fibrillar Triton X-100 (Triton insoluble structures termed the oocyte cytoplasmic lattices (CPLs. Given their similar expression profiles and mutant mouse phenotypes, we have been testing the hypothesis that MATER also plays a role in CPL formation and/or function.Herein, we show that PADI6 and MATER co-localize throughout the oocyte cytoplasm following Triton extraction, suggesting that MATER co-localizes with PADI6 at the CPLs. Additionally, the solubility of PADI6 was dramatically increased in Mater(tm/tm oocytes following Triton extraction, suggesting that MATER is involved in CPL nucleation. This prediction is supported by transmission electron microscopic analysis of Mater(+/+ and Mater(tm/tm germinal vesicle stage oocytes which illustrated that volume fraction of CPLs was reduced by 90% in Mater(tm/tm oocytes compared to Mater(+/+ oocytes.Taken together, these results suggest that, similar to PADI6, MATER is also required for CPL formation. Given that PADI6 and MATER are essential for female fertility, these results not only strengthen the hypothesis that the lattices play a critical role in mediating events during the oocyte-to-embryo transition but also increase our understanding of the molecular nature of the CPLs.
New Direction Treatment in Antidote Treatment of OPC Intoxications
International Nuclear Information System (INIS)
Dishovsky, C.
2007-01-01
The toxic effect of organophosphorus compounds (OPC) is based on inhibition of acetylcholinesterase (AChE), enzyme which plays an important physiological role in the cholinergic nervous system. The drug therapy on intoxication with OPC included mainly combination of cholinesterase reactivators and cholinolytics. There is no single AChE reactivator having the ability to sufficiently reactivate inhibited enzyme due to the high variability of chemical structure of the inhibitors. The classic oximes have antidote effect against intoxication with sarin, Vx and tabun, but are not effective against soman. HI-6 (Bulgarian ampoule form T oxidin ) has an effect against sarin, soman and Vx, and to a lesser degree against tabun. In order to improve the treatment of poisoning with highly toxic OPC, in ours laboratory we synthesized a variety of mono- and dioximes. We use different numbers of pyridinium or heterocyclic rings, different length and shape of the connecting chain between pyridinium or pyridinium-heterocyclic rings; different number and position of the oxime groups at the pyridinium rings and others. The investigations of some authors and our research showed that the compounds which present a combination between HI-6 and TMB-4 have a better antidote activity against tabun intoxications. The important finding of this study is that we synthesized complex compounds, reactivators of cholinesterase activity (including HI-6) with AMP / ATP and polycarboxilats, which have prolonged action in organism compared with original oximes. Pharmacokinetic studies showed that they are eliminated more slowly. The antidotal efficacy of these compounds after soman poisoning in rats was similar like that of the original oximes. The same tendency showed and the other pharmacological (blood pressure, EKG, breathing, neuromuscular transmission), and biochemical (ChE) investigations. (author)
International Nuclear Information System (INIS)
Thorn, C.B.
1988-01-01
The possibility of studying non-perturbative effects in string theory using a world sheet lattice is discussed. The light-cone lattice string model of Giles and Thorn is studied numerically to assess the accuracy of ''coarse lattice'' approximations. For free strings a 5 by 15 lattice seems sufficient to obtain better than 10% accuracy for the bosonic string tachyon mass squared. In addition a crude lattice model simulating string like interactions is studied to find out how easily a coarse lattice calculation can pick out effects such as bound states which would qualitatively alter the spectrum of the free theory. The role of the critical dimension in obtaining a finite continuum limit is discussed. Instead of the ''gaussian'' lattice model one could use one of the vertex models, whose continuum limit is the same as a gaussian model on a torus of any radius. Indeed, any critical 2 dimensional statistical system will have a stringy continuum limit in the absence of string interactions. 8 refs., 1 fig. , 9 tabs
Appropriate Utilization and Stocking of Antidotes in Qatar Public Hospitals
Directory of Open Access Journals (Sweden)
Rawan Salameh
2017-09-01
Full Text Available Background: There are a few studies that evaluate preparedness and availability of antidotes in the emergency setting and none have been conducted in Qatar. Published studies show that timely availability of antidotes in the emergency department setting is a common issue. To address this, we conducted a study to evaluate antidote stocking and utilization in Qatar hospital pharmacies and emergency departments. Methods: In order to evaluate the appropriate use and timely administration of antidotes, research assistants prospectively collected data on ED patients. All ED patients who received any key antidote over the 6-month study period were identified through both ED and pharmacy records. In order to evaluate the stocking of the 31 most important antidotes in our main public hospitals, a survey assessing the stocking of these key antidotes was sent to the four general hospitals in Qatar, to determine their availability and whether they are stocked in the ED or only in the main pharmacy. Results: Poison exposure was evaluated in 471 cases. Antidotes were given within 30 minutes in 73% of cases, which included atropine, calcium, dextrose, flumazenil, naloxone, pralidoxime, sodium bicarbonate, thiamine, vitamin K and scorpion and snake antivenoms. Administration occurred later than 60 minutes in 2% of cases, exclusively with N-acetylcysteine and activated charcoal. Atropine, calcium, dextrose, naloxone, pralidoxime (2-PAM, sodium bicarbonate, and anti-venoms were clinically indicated 92% of the times they were ordered. N-acetylcysteine was indicated in only 51.5% of administrations. Significant variation in antidote stocking existed between hospitals, and there was no stocked hydroxocobalamin as antidotes for cyanide poisoning or fomepizole for toxic alcohol poisoning. Conclusion: Antidote stocking varied significantly between hospitals, and antidotes necessary for cyanide and toxic alcohol poisoning were deficient in all public hospitals. The
The Role of Lattice Vibrations in Adatom Diffusion at Metal Stepped Surfaces
International Nuclear Information System (INIS)
Durakanoglu, S.
2004-01-01
Diffusion of a single atom on metal surfaces remains a subject of continuing interest in the surface science community because of the important role it plays in several technologically important phenomena such as thin-film and eptaxial growth, catalysis and chemical reactions. Except for a few studies, most of theoretical works, ranging from molecular dynamic simulations to first principle electronic structure calculations, are devoted to determination of the characteristics of the diffusion processes and the energy barriers, neglecting the contribution of lattice vibrations in adatom diffusion. However, in a series of theoretical works on self-diffusion on the flat surfaces of Cu(100), Ag(100) and Ni(100), Ulrike et al.[1-3], showed that the vibrational contributions are important and should be included in any complete description of the temperature dependence of the diffusion coefficient. In this work, it is our aim to examine the role of lattice vibrations in adatom diffusion at stepped surfaces of Cu(100) and Ni(100) within the framework of transition state theory. Ehrlich-Shwoebel energy barriers for an adatom diffusing over a step-edge are calculated through the inclusion of vibrational internal energy. Local vibrational density of states, main ingredient to the vibrational thermodynamic functions, are calculated in the harmonic approximation, using real space Green's function method with the force constants derived from interaction potentials based on the embedded atom method. We emphasize the sensitivity of the local vibrational density of states to the local atomic environment. We, furthermore, discuss the contribution of thermodynamic functions calculated from local vibrational density of states to the prefactors in diffusion coefficient
Development of antidotes: problems and strategies.
Szinicz, Ladislaus; Worek, Franz; Thiermann, Horst; Kehe, Kai; Eckert, Saskia; Eyer, Peter
2007-04-20
Antidotes against chemical warfare agents are "orphan drugs" given that these poisonings are rare. Therefore, they are of limited interest to the pharmaceutical industry. For this reason, and recognizing the increasing threat of terrorist or asymmetrical use of chemical warfare agents, the responsibility for research into medical countermeasures against these weapons is of primary interest to armies. Accordingly, the research activities of the Bundeswehr Institute of Pharmacology and Toxicology are dedicated to improving diagnosis, prophylaxis and therapy of individuals who are exposed to a chemical agent. Here, antidote development and testing are a high priority in the research program, particularly with respect to organophosphorus (OP) nerve agents and sulphur mustard. The Institute has been coordinating research activities undertaken in house and in collaboration with external researchers. The research program aims to develop primarily in vitro models to minimize the sacrifice of animals, using strategies, which involve human material early in antidote testing. An animal model using isolated mouse diaphragm demonstrated the correlation between AChE activity and neuromuscular function. A similar relationship was found between erythrocyte AChE and neuromuscular function in patients with acute OP pesticide poisoning. In vitro rate constants of the various reactions that are involved in enzyme inhibition and reactivation using human material were used for prediction of what would happen in vivo. This prediction could be confirmed in a patient with acute OP pesticide poisoning. Finally, computer models are being established to estimate the therapeutic effect of an antidote in various human poisoning scenarios. This approach is necessary to compensate for the lack of human clinical pharmacodynamic studies that are usually required for drug regulatory approval, given the obvious ethical issues preventing human volunteer studies with these agents.
International Nuclear Information System (INIS)
Mackenzie, Paul
2007-01-01
Modern lattice gauge theory calculations are making it possible for lattice QCD to play an increasingly important role in the quantitative investigation of the Standard Model. The fact that QCD is strongly coupled at large distances has required the development of nonperturbative methods and large-scale computer simulations to solve the theory. The development of successful numerical methods for QCD calculations puts us in a good position to be ready for the possible discovery of new strongly coupled forces beyond the Standard Model in the era of the Large Hadron Collider. (author)
Anisotropy engineering using exchange bias on antidot templates
Directory of Open Access Journals (Sweden)
F. J. T. Goncalves
2015-06-01
Full Text Available We explore an emerging device concept based on exchange bias used in conjunction with an antidot geometry to fine tune ferromagnetic resonances. Planar cavity ferromagnetic resonance is used to study the microwave response of NiO/NiFe bilayers with antidot structuring. A large frequency asymmetry with respect to an applied magnetic field is found across a broad field range whose underlying cause is linked to the distribution of magnetic poles at the antidot surfaces. This distribution is found to be particularly sensitive to the effects of exchange bias, and robust in regards to the quality of the antidot geometry. The template based antidot geometry we study offers advantages for practical device construction, and we show that it is suitable for broadband absorption and filtering applications, allowing tunable anisotropies via interface engineering.
Role of Defects in Self-Organized Criticality: A Directed Coupled Map Lattice Model
Tadic, Bosiljka; Ramaswamy, Ramakrishna
1996-01-01
We study a directed coupled map lattice model in two dimensions, with two degrees of freedom associated with each lattice site. The two freedoms are coupled at a fraction $c$ of lattice bonds acting as quenched random defects. In the case of conservative dynamics, at any concentration of defects the system reaches a self-organized critical state with universal critical exponents close to the mean-field values. The probability distributions follow the general scaling form $P(X,L)= L^{-\\alpha}{...
International Nuclear Information System (INIS)
Steiner, B.; Laor, U.; Berg, L. van den
1998-01-01
The hole-mobility·carrier-lifetime product of α mercuric iodide high energy radiation detectors has been enhanced through vapor crystal growth in microgravity. This improvement is closely correlated with specific characteristics of the crystal lattice, which have been identified by high resolution synchrotron X-ray diffraction imaging. These structural features and the associated performance are now being approached in terrestrial growth of α mercuric iodide. Gravity may affect the uniformity of this crystal lattice in two distinct ways: (1) directly through deformation that it imposes on the lattice during growth and (2) indirectly through convection, which mixes any extraneous material. Inclusions associated with these processes harden the lattice and facilitate lattice folding. These changes affect the electronic parameters of detectors made from the crystals. As purification procedures are optimized, the incorporation of extraneous material is curtailed, enhancing electronic properties in spite of lattice flexing through loss of precipitation hardening. These studies provide insight into the contribution of various aspects of crystalline order in α-mercuric iodide crystals to property improvement. This knowledge has led to modification of requirements for starting materials, adjustment of physical vapor growth procedures, and change in crystal handling procedures. As a result, the electronic performance of terrestrially grown radiation detectors has been improved, and the authors provide evidence that further enhancement is still possible
Development and Efficacy Testing of Next Generation Cyanide Antidotes
2013-10-01
LC-MS/MS Analysis of 2-Aminothiazoline-4-Carboxylic Acid as a Forensic Biomarker for Cyanide Poisoning . Journal of World Methodology, 26, 2(5),1-7...Generation Cyanide Antidotes PRINCIPAL INVESTIGATOR: Ilona Petrikovics, Ph.D...Testing of Next Generation Cyanide Antidotes 5a. CONTRACT NUMBER 5b. GRANT NUMBER W81XWH-12-2-0126 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) Ilona
The role of diffusion measurements in the study of crystal lattice defects
International Nuclear Information System (INIS)
Kidson, G.V.
1965-07-01
Measurements of atomic mobility in solids are frequently of direct interest to those concerned with the design, development and utilization of materials in engineering. Increasing attention, however, is currently devoted to an under standing of such properties in terms of the occurrence and nature of point and line defects in the crystals. This paper reviews some recent diffusion studies conducted at C.R,N.L. that provide, in addition to data of interest in nuclear technology, a means of gaining some insight into the more fundamental nature of the lattice defects occurring in the materials. The systems discussed are (i) self diffusion in the high temperature phase of pure zirconium (ii) solute diffusion in lead and (iii) interdiffusion of aluminum and zirconium The unusual and at present incompletely understood results described in (i) are briefly reviewed. Evidence is given to suggest that diffusion occurs either through a dense dislocation network produced as a result of a martensitic phase transformation, or, alternatively, by excess vacancies introduced into the crystal by impurities. In (ii) the extraordinarily rapid diffusion of noble metal solutes in high purity lead single crystals will be discussed n terms of the state of solution of the solute atoms. It will be shown that their diffusion behaviour can be understood by assuming that a fraction f i of the dissolved solute atoms occupy interstitial sites, The measured diffusion coefficient D m is related to the interstitial diffusion coefficient by D m = f i D i . In (iii) the formation and rapid growth of single intermetallic compound ZrAl 3 in the diffusion zone formed between pure zirconium and pure aluminum is described and the diffusion mechanism is interpreted in terms of the structure of the compound lattice. The results indicate that ZrAl 3 forms a defect lattice, leading to the relatively rapid migration of aluminum atoms. (author)
The Copernican Revolution as Story: an Antidote for Scientific Illiteracy
Wallace, P. M.
2005-08-01
``When a white-robed scientist, momentarily looking away from his microscope or cyclotron [or telescope], makes some pronouncement for the general public, he may not be understood but at least he is certain to be believed.'' The truth of this opening sentence of Anthony Standen's 1950 book Science is a Sacred Cow, as clear today as it was then, is the motivation for a new astronomy course at Berry College near Atlanta, GA, USA. To non-scientists, science is known by its products, not by what it is: a human progress. For this illiteracy an antidote is offered: the history of astronomy. In this course the story of the Copernican Revolution is told, for within this story the true nature of science can be found in its fullness. For example, Aristotle's uniform circular motion is used to emphasize the role of assumptions, and the occasional value of wrong ideas is evident in Tycho's theory and in Kepler's universe of perfect solids. Tycho's observations of Mars and Kepler's analysis illustrate the interplay of observation, theory, and technology. As a final example, the indirectness and often-unintentional nature of scientific advance can be seen in the work of Copernicus. The roles of personality and the intersections of science and society are themes throughout the course, as are the merging of disparate fields and the power of strong theories. There are other themes (e.g., coherence, the role of mathematics), but the emphasis is on the science and much of the work is quantitative. There is a laboratory component that features observations and experiments, and in order to bring the narrative to life the class spends two weeks in Poland, the Czech Republic, and Italy, touring sites that are relevant to the story of the Copernican Revolution.
Rising cost of antidotes in the U.S.: cost comparison from 2010 to 2015.
Heindel, Gregory A; Trella, Jeanette D; Osterhoudt, Kevin C
2017-06-01
Our poison control center observed a large increase in the cost of many antidotes over the past several years. The high cost of antidotes has previously been cited as a factor leading to inadequate antidote supply at some hospitals. Continued increases in the cost of antidotes may lead to further reductions in antidote supply and represent serious concerns. This research aims to quantify recent trends in the costs of antidotes in the U.S. Antidotes and minimum stocking recommendations were retrieved from published guidelines. RED BOOK Online ® was used to identify the U.S. average wholesale price (AWP) of each antidote in 2010 and 2015. The AWP in 2010 was adjusted using the U.S. Consumer Price Index to adjust for inflation. The cost of minimum stocking levels for each antidote was calculated and compared between the year 2010 and 2015. The cost of stocking many antidotes demonstrated a large increase in AWP from 2010 to 2015. Of the antidotes evaluated, 15 out of 33 had greater than 50% increase in AWP and 8 out of 33 had greater than $1000 increase in AWP. Only four antidotes demonstrated decreases in AWP greater than 10% and only one antidote had its cost of stocking decrease in AWP by more than $1000. The price increase over the last 5 years may further hinder the willingness of hospitals to stock recommended antidotes at adequate quantities. This may impede timely treatment of patients, and negatively impact poisoning outcomes. The price of many antidotes substantially increased in the United States from 2010 to 2015. Strategies should be investigated to help decrease the cost associated with stocking and use of antidotes, including dose rounding, consignment, and regional sharing.
Creativity: Performativity's Poison or Its Antidote?
Munday, Ian
2014-01-01
A common move in the study of creativity and performativity is to present the former as an antidote to the latter. Might we, therefore, see work on creativity in education as heralding an era of post-performativity? In this paper I argue that the portrayal of performativity in the literature on creativity presents an overly simplistic (vulgar?)…
Antidotes to organophosphate poisoning. 2. Thiadiazole-5-carboxaldoximes
Benschop, H.P.; Berg, G.R. van den; Hooidonk, C. van; Jong, L.P.A. de; Kientz, C.E.; Berends, F.; Kepner, L.A.; Meeter, E.; Visser, R.P.L.S.
1979-01-01
Three new nonquaternary oximes have been evaluated with respect to their antidotal activities against organophosphate poisoning. The oximes 1,2,3-thiadiazole-5-carboxaldoxime (1, pKa = 7.6), 2-methyl-1,3,4-thiadiazole-5-carboxaldoxime (2, pKa = 8.4), and 3-methyl-1,2,4-thiadiazole-5-carboxaldoxime
Editorial: Poisons and antidotes | Maitai | East and Central African ...
African Journals Online (AJOL)
Editorial: Poisons and antidotes. CK Maitai. AJOL African Journals Online. HOW TO USE AJOL... for Researchers · for Librarians · for Authors · FAQ's · More about AJOL · AJOL's Partners · Terms and Conditions of Use · Contact AJOL · News. OTHER RESOURCES... for Researchers · for Journals · for Authors · for Policy ...
Observation of Novel Low-Field FMR modes in Permalloy Antidot Arrays
de Long, Lance; Bhat, Vinayak; Farmer, Barry; Woods, Justin; Hastings, Todd; Sklenar, Joseph; Ketterson, John
2013-03-01
Permalloy films of thickness 23 nm were patterned with square arrays of square antidots (AD) with feature size D = 120 nm, and lattice constants d = 200, 300, 500 and 700 nm (total sample area = 2 mm x 2mm), using electron beam lithography. Our broad-band (frequencies f = 10 MHz-15 GHz) and narrow-band (9.7 GHz) FMR measurements of even dilute (D/d <<1) AD lattices (ADL) reveal remarkably reproducible absorption spectra in the low-frequency, hysteretic regime in which disordered domain wall (DW) patterns and unsaturated magnetization textures are expected for unpatterned films, but in the present case are strongly affected by the periodic ADL. Other modes in the saturated regime exhibit strong dependence on the angle between the applied DC field H and the ADL axes, as confirmed by our micromagnetic simulations. Novel modes are observed at DC fields above that of the uniform mode, which simulations indicate are localized at AD edges. Other novel modes are observed for DC fields below that of the uniform mode, which simulated power and phase maps indicate are confined to ADL interstices oriented parallel to H. These results show even dilute AD concentrations can effect strong control of DW evolution. Research at Kentucky is supported by U.S. DoE Grant DE-FG02-97ER45653 and NSF Grant EPS-0814194.
International Nuclear Information System (INIS)
Delogu, F.
2003-01-01
The formation of Ni-Zr binary metallic glasses resulting from the introduction of localised crystalline lattice distortions is investigated by means of constant-temperature, constant-pressure molecular dynamics simulations. Substitutional solid solutions of various composition were created by inserting substitutional atoms into a pure lattice. The insertion of Zr atoms into the regular Ni lattice determined its volume expansion, while the insertion of Ni atoms into the Zr lattice induced a volume contraction. Local lattice distortions are associated with substitutional atoms due to the size mismatch between Ni and Zr. The radial distribution functions, the rms atomic displacement and the static order parameter are used to characterise the response of the system to the insertion of substitutional atoms. The gradual loss of crystalline long-range order is accompanied by a large elastic softening. It appears that the static order parameter represents the fundamental quantity to characterise the elastic behaviour of both Ni- and Zr-based solid solutions
International Nuclear Information System (INIS)
Chadderton, L.T.; Johnson, E.; Wohlenberg, T.
1976-01-01
Void lattices in metals apparently owe their stability to elastically anisotropic interactions. An ordered array of voids on the anion sublattice in fluorite does not fit so neatly into this scheme of things. Crowdions may play a part in the formation of the void lattice, and stability may derive from other sources. (Auth.)
Co film stretching induced by lattice mismatch and annealing: The role of Graphene
Carlomagno, I.; Drnec, J.; Vlaic, S.; Vinogadrov, N.; Carlà, F.; Isern, H.; Meneghini, C.; Felici, R.
2018-02-01
Thin Co films intercalated between a Graphene capping layer and the Ir(111) surface are of interest for spintronics applications due to their peculiar magnetic properties and to their chemical stability. The structure, and then the magnetic properties, of the Co films depend on the intercalation process which is strongly influenced by the temperature, total amount of Cobalt and quality of the capping Graphene layer. In order to identify and disentangle the effects of these contributions, we report on the structural characterisation of four Co films as a function of thickness, annealing temperature, and Graphene capping. From the structural point of view, the deposition of Co on a hot Ir substrate mimics quite well the intercalation process proving the validity of the colander model describing the Graphene role during the process.
One patient's search for antidotes to nihilism in psychiatry.
Sealey, Robert
2004-01-01
A prosumer who experienced problems after misdiagnosis and mistreatment, the author searched for explanations of the short cuts inflicted on him by a mental health professional. Wanting to learn from the painful experience of willful incompetence, write to achieve closure and create a teaching tale to help other patients, the author studied the literature, read about the tradition of nihilism in psychiatry, found research reports of deviations from practice guidelines and tested three antidotes to nihilism in psychiatry.
Simonenko, V E; Sarmanaev, S Kh; Kovalev, E V; Sarmanaeva, R R; Kukhanov, A V
2014-11-01
This article analyses the approaches to the formation of specific treatment of acute poisoning in the various countries. The authors present a systematic review of scientific publications about the formation of reserves of antidote agents at medical institutions of the Russian Federation, the US, Canada, France, Spain, Greece, Norway, Czech Republic, Taiwan and Poland. A search for a variety of databases, as well as by reviewing reference lists of publications on the subject of "stockpiling antidote means". It is concluded that the antidote provision at health care institutions in different countries is insufficient. State of affairs with the formation of antidote stocks is better at hospitals of Czech Republic, France and Spain. To determine the range and volume of the stock of fixed assets necessary antidote coordination and approval of the list and the number of mandatory for every medical institution antidotes.
Energy spectrums of bilayer triangular phosphorene quantum dots and antidots
Directory of Open Access Journals (Sweden)
Z. T. Jiang
2017-04-01
Full Text Available We theoretically investigate the confined states of the bilayer triangular phosphorene dots and antidots by means of the tight-binding approach. The dependence of the energy levels on the size, the type of the boundary edges, and the orientation of the dots and antidots, and the influences of the electric and magnetic fields on the energy levels, are all completely analyzed. It is found that the energy level numbers of the bilayer dots and antidots are determined by the energy levels in two layers. The external electric field can effectively tune the energy levels of the edge states in both layers to move in opposite directions. With the increase of the magnetic field, the magnetic energy levels can approach the Landau levels of the phosphorene monolayer, the phosphorene bilayer, or both, depending on the specific geometry of the monolayer-bilayer hybrid phosphorene quantum dots. This research should be helpful for the overall understanding of the electronic properties of the multilayer hybrid phosphorene nanostructures and designing the corresponding phosphorene devices.
Selection of an aptamer antidote to the anticoagulant drug bivalirudin.
Directory of Open Access Journals (Sweden)
Jennifer A Martin
Full Text Available Adverse drug reactions, including severe patient bleeding, may occur following the administration of anticoagulant drugs. Bivalirudin is a synthetic anticoagulant drug sometimes employed as a substitute for heparin, a commonly used anticoagulant that can cause a condition called heparin-induced thrombocytopenia (HIT. Although bivalrudin has the advantage of not causing HIT, a major concern is lack of an antidote for this drug. In contrast, medical professionals can quickly reverse the effects of heparin using protamine. This report details the selection of an aptamer to bivalirudin that functions as an antidote in buffer. This was accomplished by immobilizing the drug on a monolithic column to partition binding sequences from nonbinding sequences using a low-pressure chromatography system and salt gradient elution. The elution profile of binding sequences was compared to that of a blank column (no drug, and fractions with a chromatographic difference were analyzed via real-time PCR (polymerase chain reaction and used for further selection. Sequences were identified by 454 sequencing and demonstrated low micromolar dissociation constants through fluorescence anisotropy after only two rounds of selection. One aptamer, JPB5, displayed a dose-dependent reduction of the clotting time in buffer, with a 20 µM aptamer achieving a nearly complete antidote effect. This work is expected to result in a superior safety profile for bivalirudin, resulting in enhanced patient care.
Translational Antidote Research: A Bedside to Bench Tale
Directory of Open Access Journals (Sweden)
Jeffrey Brent
2015-03-01
Full Text Available Although antidote development should proceed in an orderly fashion from observation, to experimental and safety studies, to clinical trials, this sequence is not always precisely followed. The development of fomepizole as an antidote for toxic alcohol and glycol poisoning is an example of how this may not be the case. Interest in the development of fomepizole was spurred in the 1960s. Shortly thereafter studies characterized by administration to humans commenced. The potential value of fomepizole as an antidote for methanol poisoning was highlighted by primate experiments. Simultaneously, the utility of fomepizole was shown in an experimental model of ethylene glycol poisoning. Further studies on humans showed effectiveness of fomepizole in the treatment of disulfiram-alcohol reactions and ethylene glycol poisoning. In addition, in primate experiments, the safety of fomepizole was established as the subjects tolerated serum fomepizole concentrations over 150 times higher than therapeutic target levels. Subsequent studies have validated the efficacy of fomepizole in the treatment of ethylene glycol and methanol poisonings. Fomepizole has been found to be associated with fewer complications than the alternative alcohol dehydrogenase inhibitor, ethanol. In serious cases of methanol toxicity, fomepizole has been shown to improve survival compared to that obtained with ethanol.
Energy Technology Data Exchange (ETDEWEB)
Bothner, D.; Kemmler, M.; Cozma, R.; Kleiner, R.; Koelle, D. [Physikalisches Institut and Center for Collective Quantum Phenomena, Universitaet Tuebingen (Germany); Misko, V.; Peeters, F. [Departement Fysica, Universiteit Antwerpen (Belgium); Nori, F. [Advanced Science Institute, RIKEN (Japan)
2011-07-01
The magnetic field dependent critical current I{sub c}(H) of superconducting thin films with artificial defects strongly depends on the symmetry of the defect arrangement. Likewise the critical temperature T{sub c}(H) of superconducting wire networks is heavily influenced by the symmetry of the system. Here we present experimental data on the I{sub c}(H)-T{sub c}(H) phase boundary of Nb thin films with artificial defect lattices of different symmetries. For this purpose we fabricated 60 nm thick Nb films with antidots in periodic (triangular) and five different quasiperiodic arrangements. The parameters of the antidot arrays were varied to investigate the influence of antidot diameter and array density. Experiments were performed with high temperature stability ({delta}T<1 mK) at 0.5{<=}T/T{sub c}{<=}1. From the I-V-characteristics at variable H and T we extract I{sub c}(H) and T{sub c}(H) for different voltage and resistance criteria. The experimental data for the critical current density are compared with results from numerical molecular dynamics simulations.
Lu, Genmin; DeGuzman, Francis R; Hollenbach, Stanley J; Karbarz, Mark J; Abe, Keith; Lee, Gail; Luan, Peng; Hutchaleelaha, Athiwat; Inagaki, Mayuko; Conley, Pamela B; Phillips, David R; Sinha, Uma
2013-04-01
Inhibitors of coagulation factor Xa (fXa) have emerged as a new class of antithrombotics but lack effective antidotes for patients experiencing serious bleeding. We designed and expressed a modified form of fXa as an antidote for fXa inhibitors. This recombinant protein (r-Antidote, PRT064445) is catalytically inactive and lacks the membrane-binding γ-carboxyglutamic acid domain of native fXa but retains the ability of native fXa to bind direct fXa inhibitors as well as low molecular weight heparin-activated antithrombin III (ATIII). r-Antidote dose-dependently reversed the inhibition of fXa by direct fXa inhibitors and corrected the prolongation of ex vivo clotting times by such inhibitors. In rabbits treated with the direct fXa inhibitor rivaroxaban, r-Antidote restored hemostasis in a liver laceration model. The effect of r-Antidote was mediated by reducing plasma anti-fXa activity and the non-protein bound fraction of the fXa inhibitor in plasma. In rats, r-Antidote administration dose-dependently and completely corrected increases in blood loss resulting from ATIII-dependent anticoagulation by enoxaparin or fondaparinux. r-Antidote has the potential to be used as a universal antidote for a broad range of fXa inhibitors.
Energy Technology Data Exchange (ETDEWEB)
Fang, H.; Akinoglu, E. M.; Fumagalli, P., E-mail: paul.fumagalli@fu-berlin.de [Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin (Germany); Caballero, B.; García-Martín, A. [IMM-Instituto de Microelectrónica de Madrid (CNM-CSIC), Isaac Newton 8, PTM, Tres Cantos, E-28760 Madrid (Spain); Papaioannou, E. Th. [Fachbereich Physik and Landesforschungszentrum OPTIMAS, Technische Universität Kaiserslautern, 67663 Kaiserslautern (Germany); Cuevas, J. C. [Departamento de Física Teórica de la Materia Condensada and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid (Spain); Giersig, M. [Institut für Experimentalphysik, Freie Universität Berlin, 14195 Berlin (Germany); Helmholtz Zentrum Berlin, Institute of Nanoarchitectures for Energy Conversion, 14195 Berlin (Germany)
2015-04-13
A combined experimental and theoretical study of the magneto-optic properties of a series of nickel antidot thin films is presented. The hole diameter varies from 869 down to 636 nm, while the lattice periodicity is fixed at 920 nm. This results in an overall increase of the polar Kerr rotation with decreasing hole diameter due to the increasing surface coverage with nickel. In addition, at photon energies of 2.7 and 3.3 eV, where surface-plasmon excitations are expected, we observe distinct features in the polar Kerr rotation not present in continuous nickel films. The spectral position of the peaks exhibits a red shift with decreasing hole size. This is explained within the context of an effective medium theory by a change in the effective dielectric function of the Ni thin films.
Liu, Lu; Kamm, Paul; García-Moreno, Francisco; Banhart, John; Pasini, Damiano
2017-10-01
This paper examines three-dimensional metallic lattices with regular octet and rhombicuboctahedron units fabricated with geometric imperfections via Selective Laser Sintering. We use X-ray computed tomography to capture morphology, location, and distribution of process-induced defects with the aim of studying their role in the elastic response, damage initiation, and failure evolution under quasi-static compression. Testing results from in-situ compression tomography show that each lattice exhibits a distinct failure mechanism that is governed not only by cell topology but also by geometric defects induced by additive manufacturing. Extracted from X-ray tomography images, the statistical distributions of three sets of defects, namely strut waviness, strut thickness variation, and strut oversizing, are used to develop numerical models of statistically representative lattices with imperfect geometry. Elastic and failure responses are predicted within 10% agreement from the experimental data. In addition, a computational study is presented to shed light into the relationship between the amplitude of selected defects and the reduction of elastic properties compared to their nominal values. The evolution of failure mechanisms is also explained with respect to strut oversizing, a parameter that can critically cause failure mode transitions that are not visible in defect-free lattices.
Coffee as an Antidote to Knowledge Stickiness
Blackman, Deborah; Phillips, Diane
2011-01-01
This paper considers the concept of space and its role in both knowledge creation and overcoming knowledge stickiness. Aristotelian concepts of "freedom to" and "freedom from" are used to reconceptualise space. Informal and formal spaces, concepts and places are discussed as both specific locations and as gaps providing space for knowledge…
Cyanide poisoning in Thailand before and after establishment of the National Antidote Project.
Srisuma, Sahaphume; Pradoo, Aimon; Rittilert, Panee; Wongvisavakorn, Sunun; Tongpoo, Achara; Sriapha, Charuwan; Krairojananan, Wannapa; Suchonwanich, Netnapis; Khomvilai, Sumana; Wananukul, Winai
2018-04-01
Antidote shortage is a global problem. In Thailand, the National Antidote Project (NAP) has operated since November 2010 to manage the national antidote stockpile, educate the healthcare providers on appropriate antidote use, and evaluate antidote usage. To evaluate the effect of NAP implementation on mortality rate and antidote use in cyanide poisoning cases arising from ingestion of cyanide or cyanogenic glycoside. This is a retrospective cohort of poisoning cases involving cyanide or cyanogenic glycoside ingestion reported to Ramathibodi Poison Center from 1 January 2007 to 31 December 2015. Mortality rate, antidote use, and appropriateness of antidote use (defined as correct indication, proper dosing regimen, and administration within 90 min) before and after NAP implementation were compared. Association between parameters and fatal outcomes was analyzed. A total of 343 cases involving cyanide or cyanogenic glycoside ingestion were reported to Ramathibodi Poison Center. There were 213 cases (62.1%) during NAP (Project group) and 130 cases (37.9%) pre-NAP implementation (Before group). Implementation of NAP led to increased antidote use (39.9% in Project group versus 24.6% in Before group) and a higher rate of appropriate antidote use (74.1% in Project group versus 50.0% in Before group). All 30 deaths were presented with initial severe symptoms. Cyanide chemical source and self-harm intent were associated with death (OR: 12.919, 95% CI: 4.863-39.761 and OR: 10.747, 95% CI: 3.884-28.514, respectively). No difference in overall mortality rate (13 [10.0%] deaths before versus 17 [8.0%] deaths after NAP) was found. In subgroup analysis of 80 cases with initial severe symptoms, NAP and appropriate antidote use reduced mortality (OR: 0.327, 95% CI: 0.106-0.997 and OR: 0.024, 95% CI: 0.004-0.122, respectively). In the multivariate analysis of the cases with initial severe symptoms, presence of the NAP and appropriate antidote use independently reduced the risk of
Shchesnovich, V S
2008-11-15
A light pulse propagating in a suddenly switched-on photonic lattice, when the central frequency lies in the photonic bandgap, is an analog of the Rabi model, where the two-level system is the two resonant (i.e., Bragg-coupled) Fourier modes of the pulse, while the photonic lattice serves as a monochromatic external field. A simple theory of this Rabi oscillations is given and confirmed by the numerical solution of the corresponding Maxwell equations. This is a direct, i.e., temporal analog of the Rabi effect, additionally to the spatial analog in optical beam propagation described previously [Opt. Lett.32, 1920 (2007)]. An additional high-frequency modulation of the Rabi oscillations reflects the lattice-induced energy transfer between the electric and magnetic fields of the pulse.
International Nuclear Information System (INIS)
Boghosian, B.M.
1990-01-01
In recent years an important class of cellular automata known as lattice gases have been successfully used to model a variety of physical systems, traditionally modeled by partial differential equations. The 2-D and 3-D Navier Stokes equations for single-phase and multiphase flow, Burgers' equation, and various types of diffusion equations are all examples. The first section of this chapter is meant to be a survey of the different ideas and techniques used in this simulations. In the second section, using lattice gases for the diffusion equation and for Burgers' equation as examples, the discrete Chapman-Enskog method is demonstrated. Beginning with rules governing particle motion on a lattice, the lattice Boltzmann equation is derived, and the Chapman-Enskog method is used to derive hydrodynamical equations for the conserved quantities. The approximations used at each step are discussed in detail. The intent is to provide an introduction to the Chapman-Enskog analysis for simple lattice gases in order to prepare the reader to better understand that for the (generally more complicated) models proposed for the simulation of the Navier-Stokes equations. 29 refs., 5 figs., 4 tabs
Lattice topology dictates photon statistics.
Kondakci, H Esat; Abouraddy, Ayman F; Saleh, Bahaa E A
2017-08-21
Propagation of coherent light through a disordered network is accompanied by randomization and possible conversion into thermal light. Here, we show that network topology plays a decisive role in determining the statistics of the emerging field if the underlying lattice is endowed with chiral symmetry. In such lattices, eigenmode pairs come in skew-symmetric pairs with oppositely signed eigenvalues. By examining one-dimensional arrays of randomly coupled waveguides arranged on linear and ring topologies, we are led to a remarkable prediction: the field circularity and the photon statistics in ring lattices are dictated by its parity while the same quantities are insensitive to the parity of a linear lattice. For a ring lattice, adding or subtracting a single lattice site can switch the photon statistics from super-thermal to sub-thermal, or vice versa. This behavior is understood by examining the real and imaginary fields on a lattice exhibiting chiral symmetry, which form two strands that interleave along the lattice sites. These strands can be fully braided around an even-sited ring lattice thereby producing super-thermal photon statistics, while an odd-sited lattice is incommensurate with such an arrangement and the statistics become sub-thermal.
Shchesnovich, V. S.
2008-01-01
A light pulse propagating in a suddenly switched on photonic lattice, when the central frequency lies in the photonic band gap, is an analog of the Rabi model where the two-level system is the two resonant (i.e. Bragg-coupled) Fourier modes of the pulse, while the photonic lattice serves as a monochromatic external field. A simple theory of these Rabi oscillations is given and confirmed by the numerical solution of the corresponding Maxwell equations. This is a direct, i.e. temporal, analog o...
FAR-INFRARED EXCITATIONS IN ANTIDOT SYSTEMS ON SILICON MOS STRUCTURES
HUBER, A; JEJINA, [No Value; LORENZ, H; KOTTHAUS, JP; BAKKER, S; KLAPWIJK, TM
We report on far-infrared transmission measurements of an antidot superlattice in a stacked-gate silicon MOS device. The electrons in this antidot system are electrostatically confined below the metallic mesh of the bottom gate. Sweeping the top gate voltage allows to tune the electron system from a
2015-12-01
Public Release; Distribution Unlimited 13. SUPPLEMENTARY NOTES 14. ABSTRACT Current antidotes for cyanide poisoning must be administered by intravenous... Cyanide Poisoning ; Intramuscular Injection; Intraosseous Injection; Inhalational Delivery 16. SECURITY CLASSIFICATION OF: 17. LIMITATION OF ABSTRACT...required in cyanide - poisoned victims, since they may be hypotensive with collapsed peripheral veins. Thus, intravenous antidote administration would not
International Nuclear Information System (INIS)
Bender, C.M.
1984-01-01
The finite-element method enables us to convert the operator differential equations of a quantum field theory into operator difference equations. These difference equations are consistent with the requirements of quantum mechanics and they do not exhibit fermion doubling, a problem that frequently plagues lattice treatments of fermions. Guage invariance can also be incorporated into the difference equations. On a finite lattice the operator difference equations can be solved in closed form. For the case of the Schwinger model the anomaly is computed and results in excellent agreement are obtained with the known continuum value
Lattice expansion of (Ga, Mn)As: The role of substitutional Mn and of the compensating defects
Czech Academy of Sciences Publication Activity Database
Mašek, Jan; Máca, František
2005-01-01
Roč. 108, č. 5 (2005), s. 789-704 ISSN 0587-4246 R&D Projects: GA AV ČR(CZ) IAA1010214; GA ČR GA202/04/0583 Institutional research plan: CEZ:AV0Z10100520 Keywords : density functional method * lattice constant * (Ga.Mn)As * annealing Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.394, year: 2005
Antidote availability in the municipality of Campinas, São Paulo, Brazil
Directory of Open Access Journals (Sweden)
Luciane Cristina Rodrigues Fernandes
2017-03-01
Full Text Available ABSTRACT CONTEXT AND OBJECTIVE: The lack of availability of antidotes in emergency services is a worldwide concern. The aim of the present study was to evaluate the availability of antidotes used for treating poisoning in Campinas (SP. DESIGN AND SETTING: This was a cross-sectional study of emergency services in Campinas, conducted in 2010-2012. METHODS: The availability, amount in stock, place of storage and access time for 26 antidotal treatments was investigated. In the hospitals, the availability of at least one complete treatment for a 70 kg adult over the first 24 hours of admission was evaluated based on stock and access recommendations contained in two international guidelines. RESULTS: 14 out of 17 functioning emergency services participated in the study, comprising pre-hospital services such as the public emergency ambulance service (SAMU; n = 1 and public emergency rooms for admissions lasting ≤ 24 hours (UPAs; n = 3, and 10 hospitals with emergency services. Six antidotes (atropine, sodium bicarbonate, diazepam, Phytomenadione, flumazenil and calcium gluconate were stocked in all the services, followed by 13 units that also stocked activated charcoal, naloxone and diphenhydramine or biperiden. No service stocked all of the recommended antidotes; only the regional Poison Control Center had stocks close to recommended (22/26 antidotal treatments. The 10 hospitals had almost half of the antidotes for starting treatments, but only one quarter of the antidotes was present with stocks sufficient for providing treatment for 24 hours. CONCLUSION: The stock of antidotes for attending poisoning emergencies in the municipality of Campinas is incomplete and needs to be improved.
Evaluation of processed borax as antidote for aconite poisoning.
Sarkar, Prasanta Kumar; Prajapati, Pradeep K; Shukla, Vinay J; Ravishankar, Basavaiah
2017-06-09
Aconite root is very poisonous; causes cardiac arrhythmias, ventricular fibrillation and ventricular tachycardia. There is no specific antidote for aconite poisoning. In Ayurveda, dehydrated borax is mentioned for management of aconite poisoning. The investigation evaluated antidotal effect of processed borax against acute and sub-acute toxicity, cardiac toxicity and neuro-muscular toxicity caused by raw aconite. For acute protection Study, single dose of toxicant (35mg/kg) and test drug (22.5mg/kg and 112.5mg/kg) was administered orally, and then 24h survival of animals was observed. The schedule was continued for 30 days in sub-acute protection Study with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg and 112.5mg/kg) and vehicle. Hematological and biochemical tests of blood and serum, histopathology of vital organs were carried out. The cardiac activity Study was continued for 30 days with daily doses of toxicant (6.25mg/kg), test drug (22.5mg/kg), processed borax solution (22.5mg/kg) and vehicle; ECG was taken after 1h of drug administration on 1 TB , 15th and on 30th day. For neuro-muscular activity Study, the leech dorsal muscle response to 2.5µg of acetylcholine followed by response of toxicant at 25µg and 50µg doses and then response of test drug at 25µg dose were recorded. Protection index indicates that treated borax gave protection to 50% rats exposed to the lethal dose of toxicant in acute protection Study. Most of the changes in hematological, biochemical parameters and histopathological Study induced by the toxicant in sub-acute protection Study were reversed significantly by the test drug treatment. The ventricular premature beat and ventricular tachyarrhythmia caused by the toxicant were reversed by the test drug indicate reversal of toxicant induced cardio-toxicity. The acetylcholine induced contractions in leech muscle were inhibited by toxicant and it was reversed by test drug treatment. The processed borax solution is found as an
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Stefan [DESY (Germany). Neumann Inst. for Computing
2016-11-01
These configurations are currently in use in many on-going projects carried out by researchers throughout Europe. In particular this data will serve as an essential input into the computation of the coupling constant of QCD, where some of the simulations are still on-going. But also projects computing the masses of hadrons and investigating their structure are underway as well as activities in the physics of heavy quarks. As this initial project of gauge field generation has been successful, it is worthwhile to extend the currently available ensembles with further points in parameter space. These will allow to further study and control systematic effects like the ones introduced by the finite volume, the non-physical quark masses and the finite lattice spacing. In particular certain compromises have still been made in the region where pion masses and lattice spacing are both small. This is because physical pion masses require larger lattices to keep the effects of the finite volume under control. At light pion masses, a precise control of the continuum extrapolation is therefore difficult, but certainly a main goal of future simulations. To reach this goal, algorithmic developments as well as faster hardware will be needed.
Zyoud, Sa'ed H; Waring, W Stephen; Al-Jabi, Samah W; Sweileh, Waleed M; Rahhal, Belal; Awang, Rahmat
2016-11-01
In recent years, there has been increasing interest in the role of intravenous lipid formulations as potential antidotes in patients with severe cardiotoxicity caused by drug toxicity. The aim of this study was to conduct a comprehensive bibliometric analysis of all human and animal studies featuring lipid emulsion as an antidote for the treatment of acute poisoning. The Scopus database search was performed on 5 February 2016 to analyse the research output related to intravenous lipid emulsion as an antidote for the treatment of acute poisoning. Research indicators used for analysis included total number of articles, date (year) of publication, total citations, value of the h-index, document types, countries of publication, journal names, collaboration patterns and institutions. A total of 594 articles were retrieved from Scopus database for the period of 1955-2015. The percentage share of global intravenous lipid emulsion research output showed that research output was 85.86% in 2006-2015 with yearly average growth in this field of 51 articles per year. The USA, United Kingdom (UK), France, Canada, New Zealand, Germany, Australia, China, Turkey and Japan accounted for 449 (75.6%) of all the publications. The total number of citations for all documents was 9,333, with an average of 15.7 citations per document. The h-index of the retrieved documents for lipid emulsion research as antidote for the treatment of acute poisoning was 49. The USA and the UK achieved the highest h-indices, 34 and 14, respectively. New Zealand produced the greatest number of documents with international collaboration (51.9%) followed by Australia (50%) and Canada (41.4%) out of the total number of publications for each country. In summary, we found an increase in the number of publications in the field of lipid emulsion after 2006. The results of this study demonstrate that the majority of publications in the field of lipid emulsion were published by high-income countries. Researchers from
International Nuclear Information System (INIS)
Lee, S.Y.; Claus, J.; Courant, E.D.; Hahn, H.; Parzen, G.
1985-01-01
An antisymmetric lattice for the proposed Relativistic Heavy Ion Collider at Brookhaven National Laboratory is presented, which has been designed to have (1) and energy range from 7 GeV/amu up to 100 GeV/amu; (2) a good tunability of β and betatron tune; (3) freedom in the choice of crossing angle between beams; and (4) capability of operating unequal species, for example, proton on gold. Suppression of structure resonances is achieved by a proper choice of the phase advances across the insertion and the arc cells. 8 refs., 7 figs
Antidot density dependence of magnetization reversal dynamics in ultrathin epitaxial Fe/GaAs(001)
International Nuclear Information System (INIS)
Moore, T A; Wastlbauer, G; Bland, J A C; Cambril, E; Natali, M; Decanini, D; Chen, Y
2004-01-01
Easy axis dynamic magneto-optic Kerr effect loops have been measured from ultrathin (2 nm) epitaxial Fe/GaAs(001) films patterned with arrays of 1 μm square antidots of different densities (antidot spacings 10-50 μm). The applied field was sinusoidal with frequency f = 0.01 Hz-2.3 kHz. A study of dynamic coercivity H c * as a function of f reveals an intermediate dynamic regime (20 Hz c * that is suppressed at high antidot density. The dip is attributed to timescale matching of the sweeping applied field with the domain wall propagation in the film. Suppression of the dip is explained by an increase of domain nucleation in the higher antidot density films in the intermediate dynamic regime. (letter to the editor)
A micromagnetic study of the hysteretic behavior of antidot Fe films
International Nuclear Information System (INIS)
Torres Bruna, J.M.; Bartolome, J.; Garcia Vinuesa, L.M.; Garcia Sanchez, F.; Gonzalez, J.M.; Chubykalo-Fesenko, O.A.
2005-01-01
We report on the results of a micromagnetic study of the magnetization reversal process taking place in square arrays of antidots lithographed in Fe thin films. Our study focuses on the influence on the reversal process of the antidot diameter and the distance between adjacent antidots. It is shown that the minimization of the dipolar energy term of the total system energy originates inhomogeneous moment distributions at the antidot surfaces, and that these structures and their coupling rule the reversal process. We also show that the variation of the interantidot distance in the range of a few units of the exchange length allows varying the coercive force value by a factor of four approximately
Vortices trapped in the damaged surroundings of antidots in Nb films - Depinning transition
International Nuclear Information System (INIS)
Nunes-Kapp, J.S.; Zadorosny, R.; Oliveira, A.A.M.; Vaz, A.R.; Moshkalev, S.A.; Lepienski, M.; Ortiz, W.A.
2010-01-01
The depinning transition of Vortex Matter in the presence of antidots in superconducting Nb films has been investigated. The antidots were fabricated using two different techniques, resulting in samples with arrays of diverse pinning efficiency. At low temperatures and fields, the spatial arrangement of Vortex Matter is governed by the presence of the antidots. Keeping the temperature fixed, an increase of the field induces a depinning transition. As the temperature approaches T c , the depinning frontier exhibits a characteristic kink at the temperature T k , above which the phase boundary exhibits a different regime. The lower-temperature regime is adequately described by a power-law expression, whose exponent n was observed to be inversely proportional to the pinning capability of the antidot, a feature that qualifies this parameter as a figure of merit to quantify the pinning strength of the defect.
Vortices trapped in the damaged surroundings of antidots in Nb films - Depinning transition
Energy Technology Data Exchange (ETDEWEB)
Nunes-Kapp, J.S. [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Faculdade de Tecnologia SENAI ' Antonio Adolpho Lobbe' , Sao Carlos, SP (Brazil); Zadorosny, R.; Oliveira, A.A.M. [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil); Vaz, A.R.; Moshkalev, S.A. [Centro de Componentes Semicondutores, UNICAMP, Campinas, SP (Brazil); Lepienski, M. [Departamento de Fisica, Universidade Federal do Parana, Curitiba, PR (Brazil); Ortiz, W.A., E-mail: wortiz@df.ufscar.b [Grupo de Supercondutividade e Magnetismo, Departamento de Fisica, Universidade Federal de Sao Carlos, Sao Carlos, SP (Brazil)
2010-10-01
The depinning transition of Vortex Matter in the presence of antidots in superconducting Nb films has been investigated. The antidots were fabricated using two different techniques, resulting in samples with arrays of diverse pinning efficiency. At low temperatures and fields, the spatial arrangement of Vortex Matter is governed by the presence of the antidots. Keeping the temperature fixed, an increase of the field induces a depinning transition. As the temperature approaches T{sub c}, the depinning frontier exhibits a characteristic kink at the temperature T{sub k}, above which the phase boundary exhibits a different regime. The lower-temperature regime is adequately described by a power-law expression, whose exponent n was observed to be inversely proportional to the pinning capability of the antidot, a feature that qualifies this parameter as a figure of merit to quantify the pinning strength of the defect.
Effective tunneling processes in an interferometer of helical edge states with an antidot
Rizzo, Bruno; Camjayi, Alberto; Arrachea, Liliana
2014-12-01
We consider an interferometer of edge states of a two-dimensional topological insulator with an antidot. We analyze the mechanisms leading to an effective tunneling with spin flip between different helical states.
Gastroprotective effects of novel antidotal combination in rats acutely poisoned by T-2 toxin
Jaćević Vesna; Resanović Radmila; Bočarov-Stančić Aleksandra; Đorđević Snežana; Dragojević-Simić Viktorija; Vukajlović Ana; Bokonjić D.
2010-01-01
The purpose of this experiment was to evaluate the antidotal potencies of methylprednisolone (soluble form, Lemod-solu®), nimesulide, N-acetylcysteine (Fluimucil®) and their combinations in rats treated with 1.0 LD50 (0.23 mg/kg) of trichothecene mycotoxin, T-2 toxin. Their antidotal efficacy was investigated by monitoring their effects on general condition, 24-hour-survival, body weight gain, food and water consumption and pathohistological changes in the ...
Zhao, Zongyan; Cao, Yuechan; Yi, Juan; He, Xijia; Ma, Chenshuo; Qiu, Jianbei
2012-04-23
As a promising solar-energy material, the electronic structure and optical properties of Beta phase indium sulfide (β-In(2)S(3)) are still not thoroughly understood. This paper devotes to solve these issues using density functional theory calculations. β-In(2)S(3) is found to be an indirect band gap semiconductor. The roles of its atoms at different lattice positions are not exactly identical because of the unique crystal structure. Additonally, a significant phenomenon of optical anisotropy was observed near the absorption edge. Owing to the low coordination numbers of the In3 and S2 atoms, the corresponding In3-5s states and S2-3p states are crucial for the composition of the band-edge electronic structure, leading to special optical properties and excellent optoelectronic performances. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Aziz, Shujahadeen B.; Abdullah, Omed Gh.; Hussein, Sarkawt A.
2018-03-01
The influence of anion type on silver ion reduction and drop in direct current (DC) conductivity was investigated experimentally. The structural, optical, morphological and electrical properties of the samples were investigated using x-ray diffraction (XRD), ultraviolet-visible (UV-Vis), optical micrographs (OM) and impedance spectroscopy. The XRD results reveal significant disruption in the crystalline structure of chitosan (CS) for different concentrations of silver nitrate (AgNt) salt. The localized surface resonance plasmonic (LSRP) peaks that were observed for CS:AgNt samples, along with the white silver specs detected by OM technique confirm the formation of Ag nanoparticles. The appearance of obvious dark regions in the CS:AgNt system reveals the existence of a large percentage of amorphous domains. The nonexistence of spherulitic texture confirms the amorphous nature of the samples. The second semicircle in an impedance plot can be attributed to an Ag nanoparticle grain boundary. The established relationships between dielectric constant and carrier concentration and the behavior of dielectric constant versus salt concentration were used to explain the phenomenon of ion-ion association. The continuous increase of DC conductivity was noticed at high temperatures, which was then explained on the basis of lattice energy of silver salts. The influences of anion size on the rate of silver ion reductions are also interpreted.
Congruence amalgamation of lattices
Grätzer, G; Wehrung, F; Gr\\"{a}tzer, George; Lakser, Harry; Wehrung, Friedrich
2000-01-01
J. Tuma proved an interesting "congruence amalgamation" result. We are generalizing and providing an alternate proof for it. We then provide applications of this result: --A.P. Huhn proved that every distributive algebraic lattice $D$ with at most $\\aleph\\_1$ compact elements can be represented as the congruence lattice of a lattice $L$. We show that $L$ can be constructed as a locally finite relatively complemented lattice with zero. --We find a large class of lattices, the $\\omega$-congruence-finite lattices, that contains all locally finite countable lattices, in which every lattice has a relatively complemented congruence-preserving extension.
LATTICE: an interactive lattice computer code
International Nuclear Information System (INIS)
Staples, J.
1976-10-01
LATTICE is a computer code which enables an interactive user to calculate the functions of a synchrotron lattice. This program satisfies the requirements at LBL for a simple interactive lattice program by borrowing ideas from both TRANSPORT and SYNCH. A fitting routine is included
Antidotes for poisoning by alcohols that form toxic metabolites.
McMartin, Kenneth; Jacobsen, Dag; Hovda, Knut Erik
2016-03-01
The alcohols, methanol, ethylene glycol and diethylene glycol, have many features in common, the most important of which is the fact that the compounds themselves are relatively non-toxic but are metabolized, initially by alcohol dehydrogenase, to various toxic intermediates. These compounds are readily available worldwide in commercial products as well as in homemade alcoholic beverages, both of which lead to most of the poisoning cases, from either unintentional or intentional ingestion. Although relatively infrequent in overall occurrence, poisonings by metabolically-toxic alcohols do unfortunately occur in outbreaks and can result in severe morbidity and mortality. These poisonings have traditionally been treated with ethanol since it competes for the active site of alcohol dehydrogenase and decreases the formation of toxic metabolites. Although ethanol can be effective in these poisonings, there are substantial practical problems with its use and so fomepizole, a potent competitive inhibitor of alcohol dehydrogenase, was developed for a hopefully better treatment for metabolically-toxic alcohol poisonings. Fomepizole has few side effects and is easy to use in practice and it may obviate the need for haemodialysis in some, but not all, patients. Hence, fomepizole has largely replaced ethanol as the toxic alcohol antidote in many countries. Nevertheless, ethanol remains an important alternative because access to fomepizole can be limited, the cost may appear excessive, or the physician may prefer ethanol due to experience. © 2015 The British Pharmacological Society.
Activated charcoal for pediatric poisonings: the universal antidote?
Lapus, Robert Michael
2007-04-01
For decades, activated charcoal has been used as a 'universal antidote' for the majority of poisons because of its ability to prevent the absorption of most toxic agents from the gastrointestinal tract and enhance the elimination of some agents already absorbed. This manuscript will review the history of activated charcoal, its indications, contraindications, and the complications associated with its use as reported in the literature. Recent randomized prospective studies, although with small numbers, have shown no difference in length of hospital stay, morbidity, and mortality between groups who received and did not receive activated charcoal. No study has had sufficient numbers to satisfactorily address clinical outcome in patients who received activated charcoal less than 1 h following ingestion. If used appropriately, activated charcoal has relatively low morbidity. Due to the lack of definitive studies showing a benefit in clinical outcome, it should not be used routinely in ingestions. AC could be considered for patients with an intact airway who present soon after ingestion of a toxic or life-threatening dose of an adsorbable toxin. The appropriate use of activated charcoal should be determined by the analysis of the relative risks and benefits of its use in each specific clinical scenario.
Do gastric contents modify antidotal efficacy of oral activated charcoal?
Olkkola, K T; Neuvonen, P J
1984-01-01
The effect of food on the antidotal efficacy of activated charcoal was studied in six healthy volunteers, who ingested aspirin 1000 mg, mexiletine 200 mg and tolfenamic acid 400 mg in a randomized cross-over study. Activated charcoal 25 g, suspended in water, was administered 5 min or 60 min after the drugs were taken on an empty stomach or after a standard meal. The serum concentrations and the cumulative excretion into urine of the drugs were followed for 48 h. When the drugs were taken on an empty stomach, activated charcoal given 5 min or 60 min afterwards reduced the bioavailability of the drugs by 75-98% or 10-60%, respectively. Food moderately weakened the effect of activated charcoal administered 5 min after the drugs, but when the charcoal was given 1 h later the effect was still practically the same, the reduction of absorption varying in both cases in the range of 45-85%. Thus the efficacy of charcoal given 60 min after the drugs was better after a standard meal than on an empty stomach. Presence of food in the stomach of patients with drug overdosage modifies the efficacy of activated charcoal and gives it more time to adsorb drugs in the gastrointestinal canal, possibly by slowing gastric emptying rate. PMID:6508975
Lattices for the lattice Boltzmann method.
Chikatamarla, Shyam S; Karlin, Iliya V
2009-04-01
A recently introduced theory of higher-order lattice Boltzmann models [Chikatamarla and Karlin, Phys. Rev. Lett. 97, 190601 (2006)] is elaborated in detail. A general theory of the construction of lattice Boltzmann models as an approximation to the Boltzmann equation is presented. New lattices are found in all three dimensions and are classified according to their accuracy (degree of approximation of the Boltzmann equation). The numerical stability of these lattices is argued based on the entropy principle. The efficiency and accuracy of many new lattices are demonstrated via simulations in all three dimensions.
International Nuclear Information System (INIS)
Borron, S. W.; Arias, J. C.
2007-01-01
Hazardous materials paradigms call for definitive treatment of chemical victims to begin in the 'warm zone' during decontamination. This delay may result in lethal outcomes, particularly in the case of multiple victims, where rescue may be delayed due to insufficient numbers of rescue teams. It is virtually impossible for rescuers in full protective gear to establish intravenous lines. In recent years, significant advances have been made in intraosseous (IO) infusion devices. An IO device developed in our institution, the EZ-IO, is very easily placed by rescuers in typical work uniforms. IO placement takes longer while in protective gear, but is feasible. The IO is equivalent to an intravenous line, allowing more rapid administration of antidotes in the event of chemical mass casualties. Antidotes not amenable to intramuscular administration and even those often given IM may be more effective given IO. IO administration has the following possible advantages over intravenous or intramuscular antidote administration: 1. Drugs administered IO reach the vascular system virtually instantaneously. 2. IO administration may be performed in protective clothing and could theoretically be employed while awaiting rescue. 3. IO administration may be preferred over intravenous administration in the warm zone. In summary, IO administration of antidotes should be further evaluated for use in chemical disasters. The ease and speed of placement, ready access to the vascular tree, and potential for earlier intervention make it a potentially ideal means of vascular access and antidotal administration in the mass casualty situation. (author)
[Recommendations for stocking and using antidotes in hospitals of varying levels of complexity].
Aguilar-Salmerón, Raquel; Martínez-Sánchez, Lídia; Broto-Sumalla, Antoni; Fernández de Gamarra-Martínez, Edurne; García-Pelaéz, Milagros; Nogué-Xarau, Santiago
2016-02-01
The stocking of antidotes in various care settings is a subject of debate. A group of experts in hospital pharmacy and both adult and pediatric clinical toxicology was formed to review the Spanish and international literature on the subject with the aim of updating recommendations about which antidotes to stock and in what amounts in hospitals of different levels of complexity. The experts also considered the usual indications for the use of antidotes and dosing. The amount to have on hand was defined as enough to treat an adult weighing 70 kg for 24 hours (or 3 such adults in an A-level hospital; ie, a highly complex center or the reference hospital for an area). The group also listed 34 antidotes that B-level hospitals should stock and 22 that other types of hospital should stock. The recommendations also provide a guide for using the antidotes in the forms of presentation available in Spain in 2015, a list of their main indications and recommended doses, and specific notes on each.
Ethylene glycol or methanol intoxication: which antidote should be used, fomepizole or ethanol?
Rietjens, S J; de Lange, D W; Meulenbelt, J
2014-02-01
Ethylene glycol (EG) and methanol poisoning can cause life-threatening complications. Toxicity of EG and methanol is related to the production of toxic metabolites by the enzyme alcohol dehydrogenase (ADH), which can lead to metabolic acidosis, renal failure (in EG poisoning), blindness (in methanol poisoning) and death. Therapy consists of general supportive care (e.g. intravenous fluids, correction of electrolytes and acidaemia), the use of antidotes and haemodialysis. Haemodialysis is considered a key element in the treatment of severe EG and methanol intoxication and is aimed at removing both the parent compound and its toxic metabolites, reducing the duration of antidotal treatment and shortening the hospital observation period. Currently, there are two antidotes used to block ADH-mediated metabolism of EG and methanol: ethanol and fomepizole. In this review, the advantages and disadvantages of both antidotes in terms of efficacy, safety and costs are discussed in order to help the physician to decide which antidote is appropriate in a specific clinical setting.
International Nuclear Information System (INIS)
Hall, A. H.
2007-01-01
Cyanide is a well-known toxic terrorism agent and is a major cause of mortality and morbidity in smoke inhalation victims. Terrorist attacks could start enclosed-space fires with cyanide-poisoned victims, even if cyanide itself was not utilized. Cyanide poisoning cannot be emergent confirmed by laboratory analysis and treatment with safe and efficacious antidotes must be administered empirically. Hydroxocobalamin has been recently approved by the US FDA and is a safe and efficacious antidote. Its efficacy is comparable to that of other, more toxic, cyanide antidotes. Its mechanism of action involves both direct cyanide chelation (forming non-toxic cyanocobalamin which is excreted in the urine) and nitric oxide scavenging. Adverse effects are usually limited to transient dark red-brown discoloration of urine, skin, sclera, and mucous membranes. Antidotal doses have not caused allergic reactions in cyanide-poisoned patients and only minor and easily-treated allergic reactions occurred in 2 of 136 normal volunteers. Transient, asymptomatic hypertension and reflex bradycardia have occurred in some normal volunteers, but not in seriously ill smoke inhalation victims not having significant cyanide poisoning. Hydroxocobalamin is a safe and efficacious antidote and can be empirically administered in pre-hospital or emergency department settings. It is therefore suitable for inclusion in national or multinational medication stockpiles and is already included in some national programs in the European Union.(author)
Rapid Complexation of Aptamers by Their Specific Antidotes
Directory of Open Access Journals (Sweden)
Heidi Stoll
2017-06-01
Full Text Available Nucleic acid ligands, aptamers, harbor the unique characteristics of small molecules and antibodies. The specificity and high affinity of aptamers enable their binding to different targets, such as small molecules, proteins, or cells. Chemical modifications of aptamers allow increased bioavailability. A further great benefit of aptamers is the antidote (AD-mediated controllability of their effect. In this study, the AD-mediated complexation and neutralization of the thrombin binding aptamer NU172 and Toll-like receptor 9 (TLR9 binding R10-60 aptamer were determined. Thereby, the required time for the generation of aptamer/AD-complexes was analyzed at 37 °C in human serum using gel electrophoresis. Afterwards, the blocking of aptamers’ effects was analyzed by determining the activated clotting time (ACT in the case of the NU172 aptamer, or the expression of immune activation related genes IFN-1β, IL-6, CXCL-10, and IL-1β in the case of the R10-60 aptamer. Gel electrophoresis analyses demonstrated the rapid complexation of the NU172 and R10-60 aptamers by complementary AD binding after just 2 min of incubation in human serum. A rapid neutralization of anticoagulant activity of NU172 was also demonstrated in fresh human whole blood 5 min after addition of AD. Furthermore, the TLR9-mediated activation of PMDC05 cells was interrupted after the addition of the R10-60 AD. Using these two different aptamers, the rapid antagonizability of the aptamers was demonstrated in different environments; whole blood containing numerous proteins, cells, and different small molecules, serum, or cell culture media. Thus, nucleic acid ADs are promising molecules, which offer several possibilities for different in vivo applications, such as antagonizing aptamer-based drugs, immobilization, or delivery of oligonucleotides to defined locations.
Monitoring the Effects and Antidotes of the Non-vitamin K Oral Anticoagulants
DEFF Research Database (Denmark)
Rahmat, Nur A; Lip, Gregory Y H
2015-01-01
In the last decade, we have witnessed the emergence of the oral non-vitamin K oral anticoagulants (NOACs), which have numerous advantages compared with the vitamin K antagonists, particularly their lack of need for monitoring; as a result their use is increasing. Nonetheless, the NOACs face two...... major challenges: the need for reliable laboratory assays to assess their anticoagulation effect, and the lack of approved antidotes to reverse their action. This article provides an overview of monitoring the anticoagulant effect of NOACs and their potential specific antidotes in development....
Role of the lattice dynamics in La2-xBaxCuO4 superconductor based on DFT method
Directory of Open Access Journals (Sweden)
A Tavana
2010-09-01
Full Text Available Electron-phonon coupling parameters are calculated for La2-x BaxCuO4 cuprate superconductor in a wide range of dopings, from undoped to overdoped compounds. In this study we aim to study the quality of such calculations based on DFT method so, the results of σ GGA+U electronic structure calculations are also investigated. The obtained value for electron-phonon coupling is in the same order of previous calculations but, the value obtained for the Hubbard U parameter shows that, such methods are poor in the estimation of electronic correlations to decide about the role of phonons in these compounds based on their results. Moreover, existence of several structural phase transitions with temperature and doping, lead to larger error in these calculations. Based on the calculated phonon dispersions, structural phase transitions can be resulted which shows the ability of DFT in the study of structural properties and the weakness of the strongly correlations in this properties.
Bachoc, Christine
2005-01-01
We study the Grassmannian 4-designs contained in lattices, in connection with the local property of the Rankin constant. We prove that the sequence of Barnes-Wall lattices contain Grassmannian 6-designs.
Residuation in orthomodular lattices
Directory of Open Access Journals (Sweden)
Chajda Ivan
2017-04-01
Full Text Available We show that every idempotent weakly divisible residuated lattice satisfying the double negation law can be transformed into an orthomodular lattice. The converse holds if adjointness is replaced by conditional adjointness. Moreover, we show that every positive right residuated lattice satisfying the double negation law and two further simple identities can be converted into an orthomodular lattice. In this case, also the converse statement is true and the corresponence is nearly one-to-one.
Atkinson, D; van Steenwijk, F.J.
The resistance between two arbitrary nodes in an infinite square lattice of:identical resistors is calculated, The method is generalized to infinite triangular and hexagonal lattices in two dimensions, and also to infinite cubic and hypercubic lattices in three and more dimensions. (C) 1999 American
Quaternary and tertiary aldoxime antidotes for organophosphate exposure in a zebrafish model system
Energy Technology Data Exchange (ETDEWEB)
Schmidt, Hayden R. [Department of Biology, Whittier College, Whittier, CA 90608 (United States); Radić, Zoran; Taylor, Palmer [Department of Pharmacology, Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093-0650 (United States); Fradinger, Erica A., E-mail: efrading@whittier.edu [Department of Biology, Whittier College, Whittier, CA 90608 (United States)
2015-04-15
The zebrafish is rapidly becoming an important model system for screening of new therapeutics. Here we evaluated the zebrafish as a potential pharmacological model for screening novel oxime antidotes to organophosphate (OP)-inhibited acetylcholinesterase (AChE). The k{sub i} values determined for chlorpyrifos oxon (CPO) and dichlorvos (DDVP) showed that CPO was a more potent inhibitor of both human and zebrafish AChE, but overall zebrafish AChE was less sensitive to OP inhibition. In contrast, aldoxime antidotes, the quaternary ammonium 2-PAM and tertiary amine RS-194B, showed generally similar overall reactivation kinetics, k{sub r}, in both zebrafish and human AChE. However, differences between the K{sub ox} and k{sub 2} constants suggest that zebrafish AChE associates more tightly with oximes, but has a slower maximal reactivation rate than human AChE. Homology modeling suggests that these kinetic differences result from divergences in the amino acids lining the entrance to the active site gorge. Although 2-PAM had the more favorable in vitro reactivation kinetics, RS-194B was more effective antidote in vivo. In intact zebrafish embryos, antidotal treatment with RS-194B rescued embryos from OP toxicity, whereas 2-PAM had no effect. Dechorionation of the embryos prior to antidotal treatment allowed both 2-PAM and RS-194B to rescue zebrafish embryos from OP toxicity. Interestingly, RS-194B and 2-PAM alone increased cholinergic motor activity in dechorionated embryos possibly due to the reversible inhibition kinetics, K{sub i} and αK{sub i}, of the oximes. Together these results demonstrate that the zebrafish at various developmental stages provides an excellent model for investigating membrane penetrant antidotes to OP exposure. - Highlights: • Zebrafish AChE shares significant structural similarities with human AChE. • OP-inhibited zebrafish and human AChE exhibit similar reactivation kinetics. • The zebrafish chorion is permeable to BBB penetrant and not
Topology and symmetries in gyroscopic lattices
Nash, Lisa M.; Mitchell, Noah P.; Turner, Ari M.; Irvine, William T. M.
Mechanical metamaterials - including static frames, coupled pendula, and gyroscopic lattices - can support topologically protected vibrational behavior. In particular, fast-spinning gyroscopes pinned on a honeycomb lattice break time-reversal symmetry and exhibit topologically protected, one-way edge modes. As in electronic systems, symmetries play an important role in determining the topological properties of the material. Here we present the roles of inversion symmetry, local coordination number, and time reversal symmetry on the band topology of gyroscopic metamaterials with several lattice geometries.
An All-Hazards Approach to Antidotal Therapy in Cyanide Poisoning
International Nuclear Information System (INIS)
Borron, S. W.; Arias, J. C.
2007-01-01
In recent years in the USA, increased emphasis has been placed on utilizing an 'all-hazards approach' in the development and testing of disaster plans. Disaster plans developed in this way should prepare the community to deal with a wide variety of natural and man-made emergencies, both anticipated and unanticipated in etiology. The basic approach in each disaster remains the same, with adaptation as necessary to deal with specific threats. Such an approach 'enables communities to be prepared to manage any number or type of emergencies. It facilitates prevention, preparation, response, and recovery, based on the broad scope of what could happen within and beyond the community.' (JCAHO) An all-hazards approach appears to have merit as well in the selection of antidotes for mass casualty use. Using cyanide as an example, we examine several criteria which permit a disaster preparedness entity to choose among available cyanide antidotes to permit the broadest application possible in the context of a cyanide-related chemical emergency. These criteria include: source of exposure, efficacy, safety (in the presence and absence of poisoning), safety in adults and children, ease of administration, conditions for storage and maintenance, stock rotation, and cost. The greatest limitation to the all-hazards approach in antidote selection is geographic availability. Because of the high cost of regulatory approval and historical protectionism / preferences by governments, certain regions may have little or no choice in the selection of antidotes. Hydroxocobalamin appears to best meet the requirements of an 'all-hazards' antidote for cyanide.(author)
Generalized isothermic lattices
International Nuclear Information System (INIS)
Doliwa, Adam
2007-01-01
We study multi-dimensional quadrilateral lattices satisfying simultaneously two integrable constraints: a quadratic constraint and the projective Moutard constraint. When the lattice is two dimensional and the quadric under consideration is the Moebius sphere one obtains, after the stereographic projection, the discrete isothermic surfaces defined by Bobenko and Pinkall by an algebraic constraint imposed on the (complex) cross-ratio of the circular lattice. We derive the analogous condition for our generalized isothermic lattices using Steiner's projective structure of conics, and we present basic geometric constructions which encode integrability of the lattice. In particular, we introduce the Darboux transformation of the generalized isothermic lattice and we derive the corresponding Bianchi permutability principle. Finally, we study two-dimensional generalized isothermic lattices, in particular geometry of their initial boundary value problem
Patterns of cyanide antidote use since regulatory approval of hydroxocobalamin in the United States.
Streitz, Matthew J; Bebarta, Vikhyat S; Borys, Douglas J; Morgan, David L
2014-01-01
Sodium nitrite and sodium thiosulfate are common cyanide antidotes. Hydroxocobalamin was approved for use in the United States in 2006. Our objective was to determine the frequency of antidote use as reported to the US poison centers from 2005 to 2009 and describe which antidotes were used in critically ill cyanide toxic patients. We performed a retrospective review over 5 years (2005-2009) from 61 US poison centers. We identified all cyanide-exposed cases that received a cyanide antidote. Variables collected included demographics, gastric decontamination, antidote used, predefined serious clinical effects (hypotension, cardiac arrest, respiratory arrest, and coma), and predefined serious therapies (cardiopulmonary resuscitation, vasopressors, atropine, anticonvulsant, antidysrhythmic, and intubation/ventilation). One trained abstractor abstracted each chart to a standardized electronic form. Another investigator audited 20% of the charts. Kappa values were calculated. One hundred sixty-five exposures were identified. Mean age was 42 years (range, 3-93 years). Seventy-one percent were male. Exposures were 27% ingestion and 53% inhalation. Thirty-two percent of the ingestions were suicide attempts. Twenty percent (32 of 157) of all cases died. Over all years reported, hydroxocobalamin was administered to 29% (45 of 157) of patients, sodium nitrite to 25%, and sodium thiosulfate to 46%. Hydroxocobalamin use increased from 24% to 54% from 2007 to 2009, respectively (P = 0.024). Sodium thiosulfate use decreased from 73% to 31% (P = 0.002) and sodium nitrite use decreased from 26% to 14% (P = 0.39). The proportion of cases with serious clinical effects that received hydroxocobalamin increased each year, and the proportion that received other antidotes decreased. Hydroxocobalamin was also administered more often in cases that required serious therapies and increased each year. Hydroxocobalamin use for cyanide toxicity increased each year as reported to the US poison
Anetor, J I
2010-12-01
Increased reliance on chemicals in the industrializing developing countries places new demands on them, as they have limited resources to adequately regulate exposure to these chemicals. Majority of the chemicals cause mutation in DNA among others. The consequences of increased exposure to chemicals on the genome and their mitigation by Nutrigenomics, a science concerned with the prevention of genome damage by nutritional factors is poorly recognized in these countries. Growing evidence indicates that genome instability in the absence of overt exposure to genotoxicants is a sensitive marker of nutritional deficiency. Therefore, the increasing prevalence of chemicals in these countries which contribute to genome disturbances and the widespread nutritional deficiency, at least double the risk of genome instability.Environmental pollutants such polychlorobiphenyls, metal fumes, and fly ash, common in these countries are known to increase urinary level of 8-hydroxy deoxyguanosine (8-OHdG), a marker of oxidative DNA damage, precursor of genome instability.Increasing evidence emphasizes the importance of zinc in both genetic stability and function. Zinc deficiency has been linked with oxidative stress, DNA damage and impairment of repair mechanisms as well as risk of cancer. Zinc plays an important role in vitamin A metabolism from which the retinoids are derived. Zinc is also an important component of the p53 protein, a DNA damage sensor which prevents genetic lesions contributing to genome instability.Zinc deficiency ranks among the top 10 leading causes of death in developing countries. A large proportion of the population in these countries ingests less than 50% of the RDA for Zn.This makes this genome protective nutrient among others grossly inadequate. Folate now also recognized for its role in genome stability, is among the nutrients frequently cited as critical to genome stability. Folate deficiency of sub- clinical degree is common. Reduced folate intake causes
Wentworth-Nice, Prairie; Graves, Amy
Numerical methods are used in two dimensions to find the minimum energy configuration of soft bidisperse spheres, in the presence of lattices of fixed, pointlike particles. The lattice provides a supporting structure for the jammed configuration, resulting in changes in the jamming threshold. The excess coordination number and other properties of interest near jamming are calculated as a function of the lattice structure and number density. Acknowledgement is made to the donors of the Petrolium Research Fund, administered by the American Chemical Society.
Metaharmonic Lattice Point Theory
Freeden, Willi
2011-01-01
Metaharmonic Lattice Point Theory covers interrelated methods and tools of spherically oriented geomathematics and periodically reflected analytic number theory. The book establishes multi-dimensional Euler and Poisson summation formulas corresponding to elliptic operators for the adaptive determination and calculation of formulas and identities of weighted lattice point numbers, in particular the non-uniform distribution of lattice points. The author explains how to obtain multi-dimensional generalizations of the Euler summation formula by interpreting classical Bernoulli polynomials as Green
Bebarta, Vikhyat S; Pitotti, Rebecca L; Borys, Doug J; Morgan, David L
2011-02-01
Cyanide is a common toxin in structural fires and a salt that is ingested for suicide. However, most studies have focused on the effects of inhaled cyanide. The objective of this study was to describe the incidence of cyanide ingestions, symptoms, cardiac arrest and antidotal therapy used as reported to all US poison centres over 7 years. A retrospective review of cases over 7 years as reported to 61 poison centres in the USA was performed. Sole ingestions of cyanide were identified. A trained reviewer used a standard data collection sheet within a secured electronic database. Age, intent, clinical effects, treatments, antidotes and outcomes were recorded. One investigator audited a random sample of charts. Out of 1741 exposures, 435 ingestions were identified. Most were male (68%) and the mean age was 34 years (range 1 month-83 years). 45% of cases were intentional, most commonly as a suicide attempt. 8.3% of cases died and 9% (38/435) of patients had cardiac arrest or hypotension. 13% of all cases and 26% of cases arriving at a healthcare facility received an antidote. In 35% of cases of cardiac arrest or hypotension, and in 74% of intentional ingestions, antidotes were not given. Suicide attempt was the most common reason for cyanide ingestion. Most of these patients died. Cardiac arrest or hypotension was common, but antidote use was not, particularly in critically ill patients. Research is needed to improve outcomes of cyanide-induced hypotension and cardiac arrest and to reduce barriers to antidote use.
Magnetic properties of Fe{sub 20} Ni{sub 80} antidots: Pore size and array disorder
Energy Technology Data Exchange (ETDEWEB)
Palma, J.L., E-mail: juan.palma.s@usach.cl [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Gallardo, C. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Spinu, L.; Vargas, J.M. [Advanced Material Research Institute (AMRI) and Department of Physics, University of New Orleans, New Orleans, LA 70148 (United States); Dorneles, L.S. [Departamento de Fisica, Universidade Federal de Santa Maria UFSM, Av. Roraima 1000, Camobi, Santa Maria, RS 97105-900 (Brazil); Denardin, J.C.; Escrig, J. [Departamento de Física, Universidad de Santiago de Chile (USACH), Avda. Ecuador 3493, 917-0124 Santiago (Chile); Center for the Development of Nanoscience and Nanotechnology (CEDENNA), Avda. Ecuador 3493, 917-0124 Santiago (Chile)
2013-10-15
Magnetic properties of nanoscale Fe{sub 20}Ni{sub 80} antidot arrays with different hole sizes prepared on top of nanoporous alumina membranes have been studied by means of magnetometry and micromagnetic simulations. The results show a significant increase of the coercivity as well as a reduction of the remanence of the antidot arrays, as compared with their parent continuous film, which depends on the hole size introduced in the Fe{sub 20}Ni{sub 80} thin film. When the external field is applied parallel to the antidots, the reversal of magnetization is achieved by free-core vortex propagation, whereas when the external field is applied perpendicular to the antidots, the reversal occurs through a process other than the coherent rotation (a maze-like pattern). Besides, in-plane hysteresis loops varying the angle show that the degree of disorder in the sample breaks the expected hexagonal symmetry. - Highlights: • Magnetic properties are strongly influenced by the pore diameter of the samples. • Coercive fields for antidots are higher than the values for the continuous film. • Disorder breaks the hexagonal symmetry of the sample. • Each hole acts as a vortex nucleation point. • Antidots have unique properties that allow them to be used in applications.
National Research Council Canada - National Science Library
McGuire, Dennis
1998-01-01
... invariance present in concrete morphology theories. The other, developed by Banon and Barrera, analyzes general mappings between complete lattices and develops morphological decomposition formulas for such mappings...
Energy Technology Data Exchange (ETDEWEB)
Shindler, A. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2007-07-15
I review the theoretical foundations, properties as well as the simulation results obtained so far of a variant of the Wilson lattice QCD formulation: Wilson twisted mass lattice QCD. Emphasis is put on the discretization errors and on the effects of these discretization errors on the phase structure for Wilson-like fermions in the chiral limit. The possibility to use in lattice simulations different lattice actions for sea and valence quarks to ease the renormalization patterns of phenomenologically relevant local operators, is also discussed. (orig.)
Lattice degeneracies of fermions
International Nuclear Information System (INIS)
Raszillier, H.
1983-10-01
We present a detailed description of the minimal degeneracies of geometric (Kaehler) fermions on all the lattices of maximal symmetries in n = 1, ..., 4 dimensions. We also determine the isolated orbits of the maximal symmetry groups, which are related to the minimal numbers of ''naive'' fermions on the reciprocals of these lattices. It turns out that on the self-reciprocal lattices the minimal numbers of naive fermions are equal to the minimal numbers of degrees of freedom of geometric fermions. The description we give relies on the close connection of the maximal lattice symmetry groups with (affine) Weyl groups of root systems of (semi-) simple Lie algebras. (orig.)
Edge structures and properties of triangular antidots in single-layer MoS2
Gan, Li Yong
2016-08-30
Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS2. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS2 samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS2 devices. Published by AIP Publishing.
Bateman, D Nicholas; Page, Colin B
2016-03-01
Some toxins cause their effects by affecting physiological processes that are fundamental to cell function or cause systemic effects as a result of cellular interaction. This review focuses on four examples, coumarin anticoagulants, isoniazid, methotrexate and thyroxine from the context of management of overdose as seen in acute general hospitals. The current basic clinical pharmacology of the toxin, the clinical features in overdose and evidence base for specific antidotes are discussed. The treatment for this group is based on an understanding of the toxic mechanism, but studies to determine the optimum dose of antidote are still required in all these toxins except thyroxine, where treatment dose is based on symptoms resulting from the overdose. © 2015 The British Pharmacological Society.
Edge structures and properties of triangular antidots in single-layer MoS{sub 2}
Energy Technology Data Exchange (ETDEWEB)
Gan, Li-Yong, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, Yingchun, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa; Huang, Wei [Key Laboratory of Flexible Electronics (KLOFE) and Institute of Advanced Materials (IAM), Jiangsu National Synergetic Innovation Center for Advanced Materials - SICAM, Nanjing Tech University - NanjingTech, 30 South Puzhu Road, Nanjing 211816 (China); Schwingenschlögl, Udo, E-mail: ganly@swjtu.edu.cn, E-mail: iamyccheng@njtech.edu.cn, E-mail: udo.schwingenschlogl@kaust.edu.sa [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Yao, Yingbang [Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); School of Materials and Energy, Guangdong University of Technology, Guangdong 510006 (China); Zhao, Yong [Key Laboratory of Advanced Technology of Materials (Ministry of Education), Superconductivity and New Energy R& D Center, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Physical Science and Technology, Southwest Jiaotong University, Chengdu, 610031 Sichuan (China); Zhang, Xi-xiang [Physical Science and Engineering Division (PSE), King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia); Advanced Nanofabrication and Imaging Core Lab, King Abdullah University of Science and Technology (KAUST), Thuwal 23955-6900 (Saudi Arabia)
2016-08-29
Density functional theory and experiments are employed to shed light on the edge structures of antidots in O etched single-layer MoS{sub 2}. The equilibrium morphology is found to be the zigzag Mo edge with each Mo atom bonded to two O atoms, in a wide range of O chemical potentials. Scanning electron microscopy shows that the orientation of the created triangular antidots is opposite to the triangular shape of the single-layer MoS{sub 2} samples, in agreement with the theoretical predictions. Furthermore, edges induced by O etching turn out to be p-doped, suggesting an effective strategy to realize p-type MoS{sub 2} devices.
Nitrocobinamide, a new cyanide antidote that can be administered by intramuscular injection.
Chan, Adriano; Jiang, Jingjing; Fridman, Alla; Guo, Ling T; Shelton, G Diane; Liu, Ming-Tao; Green, Carol; Haushalter, Kristofer J; Patel, Hemal H; Lee, Jangwoen; Yoon, David; Burney, Tanya; Mukai, David; Mahon, Sari B; Brenner, Matthew; Pilz, Renate B; Boss, Gerry R
2015-02-26
Currently available cyanide antidotes must be given by intravenous injection over 5-10 min, making them ill-suited for treating many people in the field, as could occur in a major fire, an industrial accident, or a terrorist attack. These scenarios call for a drug that can be given quickly, e.g., by intramuscular injection. We have shown that aquohydroxocobinamide is a potent cyanide antidote in animal models of cyanide poisoning, but it is unstable in solution and poorly absorbed after intramuscular injection. Here we show that adding sodium nitrite to cobinamide yields a stable derivative (referred to as nitrocobinamide) that rescues cyanide-poisoned mice and rabbits when given by intramuscular injection. We also show that the efficacy of nitrocobinamide is markedly enhanced by coadministering sodium thiosulfate (reducing the total injected volume), and we calculate that ∼1.4 mL each of nitrocobinamide and sodium thiosulfate should rescue a human from a lethal cyanide exposure.
Brunel, C; Widmer, C; Augsburger, M; Dussy, F; Fracasso, T
2012-11-30
Here we report the case of a 70-year-old woman who committed suicide by cyanide poisoning. During resuscitation cares, she underwent an antidote treatment by hydroxocobalamin. Postmortem investigations showed marked bright pink discolouration of organs and fluids, and a lethal cyanide blood concentration of 43 mg/L was detected by toxicological investigation. Discolouration of hypostasis and organs has widely been studied in forensic literature. In our case, we interpreted the unusual pink coloration as the result of the presence of hydroxocobalamin. This substance is a known antidote against cyanide poisoning, indicated because of its efficiency and poor adverse effects. However, its main drawback is to interfere with measurements of many routine biochemical parameters. We have tested the potential influence of this molecule in some routine postmortem investigations. The results are discussed. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.
Stability and Hopf Bifurcation for a Delayed Computer Virus Model with Antidote in Vulnerable System
Directory of Open Access Journals (Sweden)
Zizhen Zhang
2017-01-01
Full Text Available A delayed computer virus model with antidote in vulnerable system is investigated. Local stability of the endemic equilibrium and existence of Hopf bifurcation are discussed by analyzing the associated characteristic equation. Further, direction of the Hopf bifurcation and stability of the bifurcating periodic solutions are investigated by using the normal form theory and the center manifold theorem. Finally, numerical simulations are presented to show consistency with the obtained results.
Supramolecular ferric porphyrins and a cyclodextrin dimer as antidotes for cyanide poisoning.
Yamagiwa, T; Kawaguchi, A T; Saito, T; Inoue, S; Morita, S; Watanabe, K; Kitagishi, H; Koji, K; Inokuchi, S
2014-04-01
This study aimed to evaluate the antidotal effect of a newly developed supramolecular complex, ferric porphyrins and a cyclodextrin dimer (Fe(III)PIm3CD), that possess a higher binding constant and quicker binding rate to cyanide ions than those of hydroxocobalamin (OHCbl) in the presence of serum protein. First, in vitro cytochrome activity and cell viability were evaluated in murine fibroblast cells cultured with various doses of Fe(III)PIm3CD and potassium cyanide (KCN). Next, BALB/c mice were pretreated with intravenous OHCbl (0.23 mmol/kg), Fe(III)PIm3CD (0.23 mmol/kg), or saline and then received KCN (lethal dose 100% (LD100): 0.23 mmol/kg) through a stomach tube. Finally, as a resuscitation model, KCN-induced apnea was treated with a bolus injection of an equimolar dose of antidotes followed by a slow infusion of the same reagent. Fe(III)PIm3CD showed dose-dependent antidotal effects in vitro. Pretreatment with Fe(III) PIm3CD prevented KCN-induced apnea significantly better than OHCbl. Resuscitation with Fe(III)PIm3CD resulted in an earlier resumption of respiration than that seen with OHCbl. However, 24-h survival was similar among the treatments (Fe(III)PIm3CD, nine of nine mice; OHCbl, eight of nine mice). Fe(III)PIm3CD exerted significant antidotal effects on cyanide toxicity in vitro and in vivo, with a potency equal in the mortality of cyanide-poisoned mice or superior in the respiratory status during an acute phase to those of OHCbl.
Identification, solubility enhancement and in vivo testing of a cyanide antidote candidate.
Kovacs, Kristof; Ancha, Madhuri; Jane, Mario; Lee, Stephen; Angalakurthi, Siva; Negrito, Maelani; Rasheed, Senan; Nwaneri, Assumpta; Petrikovics, Ilona
2013-06-14
Present studies focused on the in vitro testing, the solubility enhancement and the in vivo testing of methyl propyl trisulfide (MPTS), a newly identified sulfur donor to treat cyanide (CN) intoxication. To enhance the solubility of the lipophilic MPTS, various FDA approved co-solvents, surfactants and their combinations were applied. The order of MPTS solubility in the given co-solvents was found to be the following: ethanol > PEG 200 ≈ PEG400 ≈ PEG300 > PG. The maximum solubility of MPTS was found at 90% ethanol of 177.11 ± 12.17 mg/ml. The order of MPTS solubility in different surfactants is Cremophor EL>Cremophor RH40>polysorbate 80>sodium deoxycholate>sodium cholate. The maximum solubility of 40.99 mg/ml was achieved with 20% Cremophor EL. A synergistic solubilizing effect encountered with the combination of 20% Cremophor EL+75% ethanol lead to a 2900-fold increase (compared to water solubility) in solubility. The in vivo efficacy using intramuscular administration was determined on a therapeutic mice model and expressed as a ratio of CN LD50 with and without the test antidote(s) (APR). Intramuscular administration was shown to be effective and the therapeutic antidotal protection by MPTS alone and MPTS+thiosulfate (TS) was significantly higher than the present therapy of TS. Copyright © 2013 Elsevier B.V. All rights reserved.
Directory of Open Access Journals (Sweden)
Bartlomiej Kalaska
Full Text Available Protamine, the only registered antidote of unfractionated heparin (UFH, may produce a number of adverse effects, such as anaphylactic shock or serious hypotension. We aimed to develop an alternative UFH antidote as efficient as protamine, but safer and easier to produce. As a starting material, we have chosen generally non-toxic, biocompatible, widely available, inexpensive, and easy to functionalize polysaccharides. Our approach was to synthesize, purify and characterize cationic derivatives of dextran, hydroxypropylcellulose, pullulan and γ-cyclodextrin, then to screen them for potential heparin-reversal activity using an in vitro assay and finally examine efficacy and safety of the most active polymers in Wistar rat and BALB/c mouse models of experimentally induced arterial and venous thrombosis. Efficacy studies included the measurement of thrombus formation, activated partial thromboplastin time, bleeding time, and anti-factor Xa activity; safety studies included the measurement of hemodynamic, hematologic and immunologic parameters. Linear, high molecular weight dextran substituted with glycidyltrimethylammonium chloride groups at a ratio of 0.65 per glucose unit (Dex40-GTMAC3 is the most potent and the safest UFH inhibitor showing activity comparable to that of protamine while possessing lower immunogenicity. Cationic polysaccharides of various structures neutralize UFH. Dex40-GTMAC3 is a promising and potentially better UFH antidote than protamine.
Directory of Open Access Journals (Sweden)
Epelbaum E.
2010-04-01
Full Text Available We review recent progress on nuclear lattice simulations using chiral eﬀective ﬁeld theory. We discuss lattice results for dilute neutron matter at next-to-leading order, three-body forces at next-to-next-toleading order, isospin-breaking and Coulomb eﬀects, and the binding energy of light nuclei.
Lattice degeneration of the retina and retinal detachment.
Semes, L P
1992-01-01
Lattice retinal degeneration is considered the most significant peripheral retinal disorder potentially predisposing to retinal breaks and retinal detachment. Lattice degeneration affects the vitreous and inner retinal layers with secondary changes as deep as the retinal pigment epithelium and perhaps the choriocapillaris. Variations in clinical appearance are the rule; geographically, lattice lesions favor the vertical meridians between the equator and the ora serrata. Lattice degeneration begins early in life and has been reported in sequential generations of the same family. Along with its customary bilateral occurrence, lattice shares other characteristics of a dystrophy. The association between the vitreous and retina in lattice lesions may be responsible for the majority of lattice-induced retinal detachments. The tumultuous event of posterior vitreous separation in the presence of abnormally strong vitreoretinal adherence is the trigger for a retinal tear that, in turn, may lead to retinal detachment. Although retinal holes in young patients with lattice degeneration may play a role in the evolution of retinal detachment, the clinical course of lattice degeneration seems to be one of dormancy rather than of progressive change. This discussion outlines the pathophysiology of lattice retinal degeneration and the relationship of pathophysiology to clinical presentation. The epidemiology of lattice degeneration is summarized, as are the possible precursors to retinal detachment. A clinical characterization of the natural history of lattice degeneration is offered, and interventions for complications are described. To conclude, management strategies from a primary-care standpoint are reviewed.
Energy Technology Data Exchange (ETDEWEB)
Rodriguez-Rodriguez, G [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Perez-Junquera, A [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Velez, M [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Anguita, J V [Instituto de Microelectronica de Madrid, CNM-CSIC, Isaac Newton 8, PTM, Tres Cantos, 28760 Madrid (Spain); Martin, J I [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Rubio, H [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain); Alameda, J M [Departamento Fisica, Facultad Ciencias, Universidad de Oviedo, Av. Calvo Sotelo s/n, 33007 Oviedo (Spain)
2007-05-21
Magnetic force microscopy (MFM) has been used to analyse the behaviour of domain walls in uniaxial amorphous Co{sub x}Si{sub 1-x} films patterned with diluted arrays of antidots by electron beam lithography. The walls are found to be pinned by the antidot array when the antidot density is high enough along the easy axis. The expansion of reversed nuclei under the influence of the tip stray field has been observed in several consecutive MFM images of the same area, showing how the competition between line tension effects and pinning by the patterned holes governs the creep motion of the 180{sup 0} walls across the array of antidots.
Energy Technology Data Exchange (ETDEWEB)
Maximenko, A., E-mail: Alexey.Maximenko@ifj.edu.pl [The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego Str. 152, 31-342 Krakow (Poland); Research Institute for Nuclear Problems of Belarusian State University, Bobruiskaya Str. 11, 220030 Minsk (Belarus); Fedotova, J. [Research Institute for Nuclear Problems of Belarusian State University, Bobruiskaya Str. 11, 220030 Minsk (Belarus); Marszałek, M.; Zarzycki, A.; Zabila, Y. [The Henryk Niewodniczanski Institute of Nuclear Physics Polish Academy of Sciences, Radzikowskiego Str. 152, 31-342 Krakow (Poland)
2016-02-15
Hard magnetic antidot arrays show promising results in context of designing of percolated perpendicular media. In this work the technology of magnetic FePd and CoPd antidot arrays fabrication is presented and correlation between surface morphology, structure and magnetic properties is discussed. CoPd and FePd antidot arrays were fabricated by deposition of Co/Pd and Fe/Pd multilayers (MLs) on porous anodic aluminum oxide templates with bowl-shape cell structure with inclined intercellular regions. FePd ordered L1{sub 0} structure was obtained by successive vacuum annealing at elevated temperatures (530 °C) and confirmed by XRD analysis. Systematic analysis of magnetization curves evidenced perpendicular magnetic anisotropy of CoPd antidot arrays, while FePd antidot arrays revealed isotropic magnetic anisotropy with increased out-of-plane magnetic contribution. MFM images of antidots showed more complicated contrast, with alternating magnetic dots oriented parallel and antiparallel to tip magnetization moment. - Highlights: • CoPd and FePd antidots were fabricated on porous anodic aluminum oxide templates. • CoPd antidot arrays have perpendicular magnetic anisotropy. • FePd antidot arrays revealed isotropic magnetic behavior. • The complex morphology of nanoporous template resulted in a complex magnetic domains image.
International Nuclear Information System (INIS)
Rodriguez-Rodriguez, G; Perez-Junquera, A; Velez, M; Anguita, J V; Martin, J I; Rubio, H; Alameda, J M
2007-01-01
Magnetic force microscopy (MFM) has been used to analyse the behaviour of domain walls in uniaxial amorphous Co x Si 1-x films patterned with diluted arrays of antidots by electron beam lithography. The walls are found to be pinned by the antidot array when the antidot density is high enough along the easy axis. The expansion of reversed nuclei under the influence of the tip stray field has been observed in several consecutive MFM images of the same area, showing how the competition between line tension effects and pinning by the patterned holes governs the creep motion of the 180 0 walls across the array of antidots
Jeong, I-K; Darling, T W; Graf, M J; Proffen, Th; Heffner, R H; Lee, Yongjae; Vogt, T; Jorgensen, J D
2004-03-12
The temperature and pressure dependence of the thermal displacements and lattice parameters were obtained across the gamma-->alpha phase transition of Ce using high-pressure, high-resolution neutron and synchrotron x-ray powder diffraction. The estimated vibrational entropy change per atom in the gamma-->alpha phase transition, DeltaS(gamma-alpha)(vib) approximately (0.75+/-0.15)k(B), is about half of the total entropy change. The bulk modulus follows a power-law pressure dependence that is well described using the framework of electron-phonon coupling. These results clearly demonstrate the importance of lattice vibrations, in addition to the spin and charge degrees of freedom, for a complete description of the gamma-->alpha phase transition in elemental Ce.
Dumestre, Danielle; Nickerson, Duncan
2014-01-01
This study aimed to assess the use of cyanide antidotes and the determine the opinion on empiric administration of hydroxocobalamin in North American burn patients with suspected smoke inhalation injuries. An online cross-sectional survey was sent to directors of 90 major burn centers in North America, which were listed on the American Burn Association Web site. A multiple-choice format was used to determine the percentage of patients tested for cyanide poisoning on admission, the current administration of a cyanide antidote based solely on clinical suspicion of poisoning, and the antidote used. To ascertain views on immediate administration of hydroxocobalamin before confirmation of cyanide poisoning an option was included to expand the response in written format. Twenty-nine of 90 burn directors (32%) completed the survey. For the population of interest, the majority of burn centers (59%) do not test for cyanide poisoning on admission and do not administer an antidote based solely on clinical suspicion of cyanide poisoning (58%). The most commonly available antidote is hydroxocobalamin (50%), followed by the cyanide antidote kit (29%). The opinion regarding instant administration of hydroxocobalamin when inhalation injury is suspected is mixed: 31% support its empiric use, 17% do not, and the remaining 52% have varying degrees of confidence in its utility. In North America, most patients burnt in closed-space fires with inhalation injuries are neither tested for cyanide poisoning in a timely manner nor empirically treated with a cyanide antidote. Although studies have shown the safety and efficacy of empiric and immediate administration of hydroxocobalamin, most centers are not willing to do so.
On singularities of lattice varieties
Mukherjee, Himadri
2013-01-01
Toric varieties associated with distributive lattices arise as a fibre of a flat degeneration of a Schubert variety in a minuscule. The singular locus of these varieties has been studied by various authors. In this article we prove that the number of diamonds incident on a lattice point $\\a$ in a product of chain lattices is more than or equal to the codimension of the lattice. Using this we also show that the lattice varieties associated with product of chain lattices is smooth.
Murray, Douglas B; Eddleston, Michael; Thomas, Simon; Jefferson, Robert D; Thompson, Adrian; Dunn, Mick; Vidler, Daniel S; Clutton, R Eddie; Blain, Peter G
2012-10-01
Management of chemical weapon casualties includes the timely administration of antidotes without contamination of rescuers. Personal protective equipment makes intravenous access difficult but does not prevent intraosseous drug administration. We therefore measured the systemic bioavailability of antidotes for organophosphorus nerve agent and cyanide poisoning when administered by the intraosseous, intravenous, and intramuscular routes in a small study of Göttingen minipigs. Animals were randomly allocated to sequentially receive atropine (0.12 mg/kg by rapid injection), pralidoxime (25 mg/kg by injection during 2 minutes), and hydroxocobalamin (75 mg/kg during 10 minutes) by the intravenous or intraosseous route, or atropine and pralidoxime by the intramuscular route. Plasma concentrations were measured for 6 hours to characterize the antidote concentration-time profiles for each route. Maximum plasma concentrations of atropine and pralidoxime occurred within 2 minutes when administered by the intraosseous route compared with 8 minutes by the intramuscular route. Maximum plasma hydroxocobalamin concentration occurred at the end of the infusion when administered by the intraosseous route. The mean area under the concentration-time curve by the intraosseous route was similar to the intravenous route for all 3 drugs and similar to the intramuscular route for atropine and pralidoxime. This study showed rapid and substantial antidote bioavailability after intraosseous administration that appeared similar to that of the intravenous route. The intraosseous route of antidote administration should be considered when intravenous access is difficult. Copyright © 2012. Published by Mosby, Inc.
Optical lattices: Orbital dance
Lewenstein, Maciej; Liu, W. Vincent
2011-02-01
Emulating condensed-matter physics with ground-state atoms trapped in optical lattices has come a long way. But excite the atoms into higher orbital states, and a whole new world of exotic states appears.
Root lattices and quasicrystals
Baake, M.; Joseph, D.; Kramer, P.; Schlottmann, M.
1990-10-01
It is shown that root lattices and their reciprocals might serve as the right pool for the construction of quasicrystalline structure models. All noncrystallographic symmetries observed so far are covered in minimal embedding with maximal symmetry.
DEFF Research Database (Denmark)
Risager, Morten S.; Södergren, Carl Anders
2017-01-01
It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior of the den......It is well known that the angles in a lattice acting on hyperbolic n -space become equidistributed. In this paper we determine a formula for the pair correlation density for angles in such hyperbolic lattices. Using this formula we determine, among other things, the asymptotic behavior...... of the density function in both the small and large variable limits. This extends earlier results by Boca, Pasol, Popa and Zaharescu and Kelmer and Kontorovich in dimension 2 to general dimension n . Our proofs use the decay of matrix coefficients together with a number of careful estimates, and lead...
International Nuclear Information System (INIS)
Mackenzie, Paul
1989-01-01
The forty-year dream of understanding the properties of the strongly interacting particles from first principles is now approaching reality. Quantum chromodynamics (QCD - the field theory of the quark and gluon constituents of strongly interacting particles) was initially handicapped by the severe limitations of the conventional (perturbation) approach in this picture, but Ken Wilson's inventions of lattice gauge theory and renormalization group methods opened new doors, making calculations of masses and other particle properties possible. Lattice gauge theory became a major industry around 1980, when Monte Carlo methods were introduced, and the first prototype calculations yielded qualitatively reasonable results. The promising developments over the past year were highlighted at the 1988 Symposium on Lattice Field Theory - Lattice 88 - held at Fermilab
Automated Lattice Perturbation Theory
Energy Technology Data Exchange (ETDEWEB)
Monahan, Christopher
2014-11-01
I review recent developments in automated lattice perturbation theory. Starting with an overview of lattice perturbation theory, I focus on the three automation packages currently "on the market": HiPPy/HPsrc, Pastor and PhySyCAl. I highlight some recent applications of these methods, particularly in B physics. In the final section I briefly discuss the related, but distinct, approach of numerical stochastic perturbation theory.
Kiefel, Martin; Jampani, Varun; Gehler, Peter V.
2014-01-01
This paper presents a convolutional layer that is able to process sparse input features. As an example, for image recognition problems this allows an efficient filtering of signals that do not lie on a dense grid (like pixel position), but of more general features (such as color values). The presented algorithm makes use of the permutohedral lattice data structure. The permutohedral lattice was introduced to efficiently implement a bilateral filter, a commonly used image processing operation....
Vortex lattices in layered superconductors
International Nuclear Information System (INIS)
Prokic, V.; Davidovic, D.; Dobrosavljevic-Grujic, L.
1995-01-01
We study vortex lattices in a superconductor--normal-metal superlattice in a parallel magnetic field. Distorted lattices, resulting from the shear deformations along the layers, are found to be unstable. Under field variation, nonequilibrium configurations undergo an infinite sequence of continuous transitions, typical for soft lattices. The equilibrium vortex arrangement is always a lattice of isocell triangles, without shear
Antidotal Efficacy of a New Combination in Treatment of Subacute T-2 Toxin Poisoning in Rats
International Nuclear Information System (INIS)
Jacevic, V. M.; Bocarov-Stancic, A. S.; Resanovic, R. D.; Djordjevic, S. B.; Bokonjic, D. R.
2007-01-01
Trichothecene mycotoxin, T-2 toxin is a natural metabolite of Fusarium fungi. T-2 toxin possesses several properties (significant persistence in the environment, cheap manufacture, difficult detection and absence of a specific antidote) that make it a very dangerous potential chemical warfare agent. In our previous experiments, nonsteroidal anti-inflammatory drug (NSAID) nimesulide (NIM), as a selective COX-2 inhibitor, and zeolite absorbent (Min-a-zel Plus, MINplus) administered separately showed a good protective effects against general toxicity induced by T-2 toxin (T2). The aim of this study was to evaluate the antidotal potential of the combination of these two antidotes. T2 was given in a dose of 0.15 mg/kg sc (0.1 LD50), 5 times per week, 4 weeks to adult Wistar rats. Protected animals were given NIM (20 mg/kg im) or/and MINplus (40 mg/kg po) each time immediately after T2. Mortality, general condition, body weight gain, food and water consumption and gut alterations of the animals were registered on a daily basis during 4 weeks. Treatment with NIM or/and MINplus significantly reduced mortality of the rats treated only with T2. Body weight gain, food and water consumption were significantly decreased in T2-treated animals compared to control ones (p < 0.001), what was not the case in the protected rats. In the groups treated with NIM and MINplus gut alterations were significantly less severe than those observed in animals receiving T2 alone (p less than 0.001). These results imply that combined treatment with nimesulide and zeolite absorbent affords a significant protection against subacute T-2 toxin poisoning in rats.(author)
Tummala, Ramyashree; Kavtaradze, Ana; Gupta, Anjan; Ghosh, Raktim Kumar
2016-07-01
The Vitamin K antagonist warfarin was the only oral anticoagulant available for decades for the treatment of thrombosis and prevention of thromboembolism until Direct Oral Anticoagulants (DOACs); a group of new oral anticoagulants got approved in the last few years. Direct thrombin inhibitor: dabigatran and factor Xa inhibitors: apixaban, rivaroxaban, and edoxaban directly inhibit the coagulation cascade. DOACs have many advantages over warfarin. However, the biggest drawback of DOACs has been the lack of specific antidotes to reverse the anticoagulant effect in emergency situations. Activated charcoal, hemodialysis, and activated Prothrombin Complex Concentrate (PCC) were amongst the nonspecific agents used in a DOAC associated bleeding but with limited success. Idarucizumab, the first novel antidote against direct thrombin inhibitor dabigatran was approved by US FDA in October 2015. It comprehensively reversed dabigatran-induced anticoagulation in a phase I study. A phase III trial on Idarucizumab also complete reversal of anticoagulant effect of dabigatran. Andexanet alfa (PRT064445), a specific reversal agent against factor Xa inhibitors, showed a complete reversal of anticoagulant activity of apixaban and rivaroxaban within minutes after administration without adverse effects in two recently completed parallel phase III trials ANNEXA-A and ANNEXA-R respectively. It is currently being studied in ANNEXA-4, a phase IV study. Aripazine (PER-977), the third reversal agent, has shown promising activity against dabigatran, apixaban, rivaroxaban, as well as subcutaneous fondaparinux and LMWH. This review article summarizes pharmacological characteristics of these novel antidotes, coagulation's tests affected, available clinical and preclinical data, and the need for phase III and IV studies. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.
Effects of Cheap Antidotes; Sodium Bicarbonate and Magnesium Sulfate in Organophosphorous Poisoning
International Nuclear Information System (INIS)
Balali-Mood, M.; Afshari, R.
2007-01-01
Organophosphorous (OP) compounds have been used as pesticides and chemical warfare nerve agents. Despite administration of well known antidotes (atropine and oximes), morbidity and mortality of OP poisoning were still high. Besides, oximes are very expensive and not available in most developing countries. It was thus aimed to study the effects of cheap available antidotes; sodium bicarbonate and magnesium sulfate in OP poisoning. In addition to the standard antidotal treatment, out of 117 patients (63M, 47F) aged 25.2 ± 9.5 years with moderate to severe acute OP pesticide poisoning 59 were given sodium bicarbonate 5 mEq/kg in 60 min. followed by 5-6 mEq/kg/day to obtain arterial blood pH of 7.45 to 7.55. Arterial blood pH increased significantly (p less than 0.01) to 7.48 ± 0.05 compared to the controls (7.32 ± 0.06). Morbidity based on hospitalization days reduced significantly (p less than 0.05) from 5.62 ± 3.4 in the controls to 3.1 ± 2.6 days in the sodium bicarbonate group. Total atropine dose was also significantly (p less than 0.05) lower in the test group. Mortality was lower, but not significantly due to the low numbers (5 and 2 of the controls and test group, respectively). Sodium bicarbonate appeared to be effective and could be added to the treatment regime of OP poisoning. Magnesium sulfate was administered four gram intravenously only for the first 24 hr of hospitalization day for the patients with moderate to severe OP poisoning in a pilot study. The results were promising and thus further investigations are continued.(author)
Lepik, Katherine J; Sobolev, Boris G; Levy, Adrian R; Purssell, Roy A; Dewitt, Christopher R; Erhardt, Gunnar D; Baker, Jane L; Kennedy, James R; Daws, Derek E
2011-06-01
Little is known about medication errors which occur with the antidotes ethanol and fomepizole, used for treatment of methanol and ethylene glycol poisoning. Study objectives were to describe and compare the frequency, type, outcome and underlying causes of medication errors associated with ethanol and fomepizole. Patients aged ≥13 years were included if they were hospitalized in 1996-2005 for methanol or ethylene glycol poisoning and treated with ethanol or fomepizole. Charts from 10 hospitals were separately reviewed by two abstracters who recorded case details. A consensus panel of clinicians used the abstracted data to identify medication errors and classify error outcome. Fisher's exact test determined significant differences in the proportion of ethanol and fomepizole-treated cases with medication error and univariate logistic regression identified risk factors associated with harmful dosage errors. There were 145 ethanol- and 44 fomepizole-treated cases. There was ≥1 medication error in 113/145 (78%) ethanol- and 20/44 (45%) fomepizole-treated cases (p = 0.0001) with more ethanol-related errors involving excessive dose, inadequate monitoring and inappropriate antidote duration. Harmful errors occurred in 19% of ethanol- and 7% of fomepizole-treated cases (p = 0.06) and were largely due to excessive antidote dose or delayed antidote initiation. Occurrence of harmful dosage error was reduced in cases with Poison Control Centre consultation, odds ratio (95% confidence interval) 0.39 (0.17, 0.91), hemodialysis 0.37 (0.16, 0.88), or fomepizole versus ethanol 0.24 (0.06, 1.04). Fomepizole was less prone to medication error than ethanol. Error-related harm was most commonly due to excessive antidote dose or delayed antidote initiation.
Local covering optimality of lattices: Leech lattice versus root lattice $E_8$
A. Schuermann; F. Vallentin (Frank)
2005-01-01
textabstractWe show that the Leech lattice gives a sphere covering which is locally least dense among lattice coverings. We show that a similar result is false for the root lattice $E_8$. For this we construct a less dense covering lattice whose Delone subdivision has a common refinement with the
The contamination of scientific literature: looking for an antidote
Liotta, Marcello
2017-04-01
Science may have very strong implications for society. The knowledge of the processes occurring around the society represents a good opportunity to take responsible decisions. This is particularly true in the field of geosciences. Earthquakes, volcanic eruptions, landslides, climate changes and many other natural phenomena still need to be further investigated. The role of the scientific community is to increase the knowledge. Each member can share his own ideas and data thus allowing the entire scientific community to receive a precious contribution. The latter one often derives from research activities, which are expensive in terms of consumed time and resources. Nowadays the sharing of scientific results occurs through the publication on scientific journals. The reading of available scientific literature thus represents a unique opportunity to define the state of the art on a specific topic and to address research activities towards something new. When published results are obtained through a rigorous scientific process, they constitute a solid background where each member can add his ideas and evidences. Differently, published results may be affected by scientific misconduct; they constitute a labyrinth where the scientists lose their time in the attempt of truly understanding the natural processes. The normal scientific dialectic should unmask such results, thus avoiding literature contamination and making the scientific framework more stimulating. The scientific community should look for the best practice to reduce the risk of literature contamination.
Kovalevsky, Andrey; Blumenthal, Donald K.; Cheng, Xiaolin; Taylor, Palmer; Radić, Zoran
2016-01-01
Acetylcholinesterase (AChE; EC 3.1.1.7), an essential enzyme of cholinergic neurotransmission in vertebrates, is a primary target in acute nerve agent and organophosphate (OP) pesticide intoxication. Catalytically inactive OP–AChE conjugates formed between the active-center serine and phosphorus of OPs can, in principle, be reactivated by nucleophilic oxime antidotes. Antidote efficacy is limited by the structural diversity of OP–AChE conjugates resulting from differences in the structure of the conjugated OP, the different active-center volumes they occupy when conjugated to the active-center serine of AChE, and the distinct chemical characteristics of both OPs and oximes, documented in numerous X-ray structures of OP-conjugated AChEs. Efforts to improve oxime reactivation efficacy by AChE structure–based enhancement of oxime structure have yielded only limited success. We outline here potential limitations of available AChE X-ray structures that preclude an accurate prediction of oxime structures, which are necessary for association in the OP–AChE gorge and nucleophilic attack of the OP-conjugated phosphorus. PMID:27371941
International Nuclear Information System (INIS)
Kuca, Kamil; Jun, Daniel; Jung, Young Sik; Kim, Tae Hyuk; Cabal, Jiri
2006-01-01
Nerve agents (sarin, tabun, soman and VX) are class of military important substances able to cause many severe intoxications during few minutes. Currently, the threat of misuse of these agents is daily discussed. Unfortunately, there is no single antidote able to treat intoxication caused by all of these agents. Owing to this fact, new generation of antidotes, especially acetylcholinesterase (AChE: EC 3.1.1.7) reactivators, is still developed. In this study, we have tested four newly developed AChE reactivators: 1-(4-hydroxyiminomethylpyridinium)- 5-(4-carbamoylpyridinium)-3-oxa-pentane dibromide (1), 1-(3-hydroxyiminomethylpyridinium)- 5-(4-carbamoylpyridinium)-3-oxa-pentane dibromide (2), 1,5-bis(2-hydroxyiminomethylpyridinium)- 3-oxa-pentane dichloride (3) and 1,5-bis(4-hydroxyiminomethylpyridinium)-3-oxa-pentane dibromide (4) for their potency to reactivate in vitro tabun and cyclosarin-inhibited AChE. Their reactivation efficacy was compared with currently the most promising oxime HI-6 (1-(2-hydroxyiminomethylpyridinium)-3-(4- carbamoylpyridinium)-2-oxa-propane dichloride). According to obtained results, two AChE reactivators 1 and 4 were able to reactivate tabun-inhibited AChE. On the contrary, there was no better AChE reactivator than HI- 6 able to reactivate cyclosarin-inhibited AChE
Golderman, Valery; Shavit-Stein, Efrat; Tamarin, Ilia; Rosman, Yossi; Shrot, Shai; Rosenberg, Nurit
2016-01-01
Organophosphates (OPs) are potentially able to affect serine proteases by reacting with their active site. The potential effects of OPs on coagulation factors such as thrombin and on coagulation tests have been only partially characterized and potential interactions with OPs antidotes such as oximes and muscarinic blockers have not been addressed. In the current study, we investigated the in vitro interactions between coagulation, thrombin, the OP paraoxon, and its antidotes obidoxime and atropine. The effects of these substances on thrombin activity were measured in a fluorescent substrate and on coagulation by standard tests. Both paraoxon and obidoxime but not atropine significantly inhibited thrombin activity, and prolonged prothrombin time, thrombin time, and partial thromboplastin time. When paraoxon and obidoxime were combined, a significant synergistic effect was found on both thrombin activity and coagulation tests. In conclusion, paraoxon and obidoxime affect thrombin activity and consequently alter the function of the coagulation system. Similar interactions may be clinically relevant for coagulation pathways in the blood and possibly in the brain. PMID:27689805
Effect of charcoal-drug ratio on antidotal efficacy of oral activated charcoal in man.
Olkkola, K T
1985-01-01
The effect of charcoal-drug ratio on the antidotal efficacy of oral activated charcoal was studied in six healthy volunteers in a randomized cross-over study and compared with the adsorption capacity of activated charcoal in vitro. Aminosalicylic acid (PAS) 1 g and 5 g were ingested on an empty stomach in 30 ml of water. Immediately afterwards the subjects ingested 50 g of activated charcoal in 300 ml of water or 300 ml of water only. PAS 10 g 20 g were only given with 50 g of activated charcoal administered immediately afterwards. The plasma concentrations and the cumulative excretion of PAS into urine were measured for 48 h. Increasing the dose of PAS from 1 g to 20 g reduced the antidotal efficacy of activated charcoal: at a charcoal-drug ratio of 50:1 under 5% of the dose was absorbed but at a ratio of 2.5:1 about 37%. These data correlated well to the saturation of adsorption capacity of charcoal in vitro. To minimize the possibility of saturation of the adsorption capacity of charcoal in acute intoxications where the amount and type of drug taken is usually unknown, large doses (50-100 g) of activated charcoal should be used. PMID:4027120
Saffron as an antidote or a protective agent against natural or chemical toxicities.
Razavi, Bibi Marjan; Hosseinzadeh, Hossein
2015-05-01
Saffron (Crocus sativus) is an extensively used food additive for its color and taste. Since ancient times this plant has been introduced as a marvelous medicine throughout the world. The wide spectrum of saffron pharmacological activities is related to its major constituents including crocin, crocetin and safranal. Based on several studies, saffron and its active ingredients have been used as an antioxidant, antiinflammatory and antinociceptive, antidepressant, antitussive, anticonvulsant, memory enhancer, hypotensive and anticancer. According to the literatures, saffron has remarkable therapeutic effects. The protective effects of saffron and its main constituents in different tissues including brain, heart, liver, kidney and lung have been reported against some toxic materials either natural or chemical toxins in animal studies.In this review article, we have summarized different in vitro and animal studies in scientific databases which investigate the antidotal and protective effects of saffron and its major components against natural toxins and chemical-induced toxicities. Due to the lake of human studies, further investigations are required to ascertain the efficacy of saffron as an antidote or a protective agent in human intoxication.
Energy Technology Data Exchange (ETDEWEB)
Catterall, Simon; Kaplan, David B.; Unsal, Mithat
2009-03-31
We provide an introduction to recent lattice formulations of supersymmetric theories which are invariant under one or more real supersymmetries at nonzero lattice spacing. These include the especially interesting case of N = 4 SYM in four dimensions. We discuss approaches based both on twisted supersymmetry and orbifold-deconstruction techniques and show their equivalence in the case of gauge theories. The presence of an exact supersymmetry reduces and in some cases eliminates the need for fine tuning to achieve a continuum limit invariant under the full supersymmetry of the target theory. We discuss open problems.
[Poisons and antidotes according to Gunyetü'l Muhassilin and an 18th century Ottoman pamphlet].
Tuğ, R
2000-01-01
This study deals with the chapter on poisons (Sümum) of Gunyetü'l-Muhassilin, a translation, and a pamphlet on antidotes called Panzehir, by Ahmed Sani, one of the most prominent figures of the Ottoman physicians. As a foreword, the terminology related with the subject; and an introduction to the Islamic medical theory, the basis of the subject, is discussed. The main topics on poisons are; protection against and treatment of poisons; being poisoned by the sting of insects, snakes etc. and diseases such as rabies, as a result of bites of animals and their treatment; treatment of poisoned suppuration; insecticide drugs and measures; and common drugs against all kinds of poisons. Immunization and nutrition with respect to being poisoned; and preventive measures against insects; and mineral and organic antidotes are also discussed. The classification of diseases and treatment ase evaluated on the humoral theory basis. The treatment of insect poisoning is viewed from the perspective of its symptoms. The pamphlet named Panzehir is about a special antidote, the bezoar stone. This antidote is divided into two, of the mineral and the animal origin and the uses of the bezoar are discussed. A vocabulary is added to help readers to understand the terminology.
Weidner, Carrie; Yu, Hoon; Anderson, Dana
2015-05-01
This work introduces a method to perform interferometry using atoms trapped in an optical lattice. Starting at t = 0 with atoms in the ground state of a lattice potential V(x) =V0cos [ 2 kx + ϕ(t) ] , we show that it is possible to transform from one atomic wavefunction to another by a prescribed shaking of the lattice, i.e., by an appropriately tailored time-dependent phase shift ϕ(t) . In particular, the standard interferometer sequence of beam splitting, propagation, reflection, reverse propagation, and recombination can be achieved via a set of phase modulation operations {ϕj(t) } . Each ϕj(t) is determined using a learning algorithm, and the split-step method calculates the wavefunction dynamics. We have numerically demonstrated an interferometer in which the shaken wavefunctions match the target states to better than 1 % . We carried out learning using a genetic algorithm and optimal control techniques. The atoms remain trapped in the lattice throughout the full interferometer sequence. Thus, the approach may be suitable for use in an dynamic environment. In addition to the general principles, we discuss aspects of the experimental implementation. Supported by the Office of Naval Research (ONR) and Northrop Grumman.
Williamson, S. Gill
2010-01-01
Will the cosmological multiverse, when described mathematically, have easily stated properties that are impossible to prove or disprove using mathematical physics? We explore this question by constructing lattice multiverses which exhibit such behavior even though they are much simpler mathematically than any likely cosmological multiverse.
Energy Technology Data Exchange (ETDEWEB)
Maturana, G.; Vanden Doel, C.P. (California Univ., Santa Cruz (USA). Physics Dept.)
1983-04-07
We study spin 3/2 fields on the lattice. Species doubling is found to be totally curable with an analogue of Wilson's method and partially with an analogue of the Kogut-Susskind formalism. Only the latter preserves local supersymmetry but describes at least four species.
Baiesi, M.; Barkema, G.T.; Carlon, E.
2010-01-01
We study a model of “elastic” lattice polymer in which a fixed number of monomers m is hosted by a self-avoiding walk with fluctuating length l. We show that the stored length density m 1− l /m scales asymptotically for large m as m= 1− /m+. . . , where is the polymer entropic exponent, so that can
International Nuclear Information System (INIS)
Krojts, M.
1987-01-01
The book by the known american physicist-theoretist M.Kreuts represents the first monography in world literature, where a new perspective direction in elementary particle physics and quantum field theory - lattice formulation of gauge theories is stated systematically. Practically all main ideas of this direction are given. Material is stated in systematic and understandable form
International Nuclear Information System (INIS)
Autin, B.
1984-01-01
After a description of the constraints imposed by the cooling of Antiprotons on the lattice of the rings, the reasons which motivate the shape and the structure of these machines are surveyed. Linear and non-linear beam optics properties are treated with a special amplification to the Antiproton Accumulator. (orig.)
Indian Academy of Sciences (India)
activities in non-perturbative QCD. Keywords. Deflation; overlap operator; GPU; CUDA. PACS Nos 11.15.Ha; 12.38.-t. 1. Introduction. The lattice gauge theory subgroup of the working group in non-perturbative QCD consisted of Mridupavan Deka, Sourendu Gupta, N D Hari Dass, Rajarshi Roy, Sayantan Sharma and.
Noetherian and Artinian Lattices
Directory of Open Access Journals (Sweden)
Derya Keskin Tütüncü
2012-01-01
Full Text Available It is proved that if L is a complete modular lattice which is compactly generated, then Rad(L/0 is Artinian if, and only if for every small element a of L, the sublattice a/0 is Artinian if, and only if L satisfies DCC on small elements.
Decidability in Orthomodular Lattices
Hyčko, Marek; Navara, Mirko
2005-12-01
We discuss the possibility of automatic simplification of formulas in orthomodular lattices. We describe the principles of a program which decides the validity of equalities and inequalities, as well as implications between them and other important relations significant in quantum mechanics.
Valiakos, E; Marselos, M; Sakellaridis, N; Constantinidis, Th; Skaltsa, H
2015-04-02
This paper focuses on the plants quoted in the recipes of the first chapter entitled "About the Antidotes" belonging to the first and largest section "Element Alpha" of Nikolaos Myrepsos׳ Dynameron, a medieval medical manuscript. Nikolaos Myrepsos was a Byzantine physician at the court of John III Doukas Vatatzes at Nicaea (13th century). He wrote in Greek a rich collection of 2667 recipes, the richest number known in late Byzantine era, conventionally known as Dynameron and divided into 24 sections, the "Elements". The only existing translation of this work is in Latin, released in 1549 in Basel by Leonhart Fuchs. Since no other translation has ever been made in any language, this work still remains poorly known. Our primary source material was the codex written in 1339 and kept in the National Library of France (in Paris) under the number grec. 2243. For comparison, all the other codices, which contain the entire manuscript, have also been studied, namely the codices EBE 1478 (National Library of Greece, Athens), grec. 2237 and grec. 2238 (both in Paris), Lavra Ε 192 (Mont Athos, Monastery of Megisti Lavra), Barocci 171 (Oxford) and Revilla 83 (Escorial). The exhaustive study of the "About the Antidotes" led us to the interpretation of 293 plant names among which we recognized 39 medicinal plants listed by the European Medicines Agency, (Herbal Medicines, www.ema.eu); the therapeutic indications of some of them provided by Myrepsos were similar or related to their current ones, as given in their monographs. The plants belong to various families of which the most frequent are: Apiaceae 10.6%; Lamiaceae 9.2%; Asteraceae 8.9%; Fabaceae 6.8% and Rosaceae 5.1%. The most frequently mentioned plants even under several different names are the following: Apium graveolens L., Crocus sativus L., Nardostachys jatamansi (D. Don) DC., Zingiber officinale Roscoe, Rosa centifolia L., Syzygium aromaticum (L.) Merr. & L.M. Perry, Papaver somniferum L., Costus sp., Petroselinum
Conical diffraction in honeycomb lattices
International Nuclear Information System (INIS)
Ablowitz, Mark J.; Nixon, Sean D.; Zhu Yi
2009-01-01
Conical diffraction in honeycomb lattices is analyzed. This phenomenon arises in nonlinear Schroedinger equations with honeycomb lattice potentials. In the tight-binding approximation the wave envelope is governed by a nonlinear classical Dirac equation. Numerical simulations show that the Dirac equation and the lattice equation have the same conical diffraction properties. Similar conical diffraction occurs in both the linear and nonlinear regimes. The Dirac system reveals the underlying mechanism for the existence of conical diffraction in honeycomb lattices.
Basis reduction for layered lattices
Torreão Dassen, Erwin
2011-01-01
We develop the theory of layered Euclidean spaces and layered lattices. We present algorithms to compute both Gram-Schmidt and reduced bases in this generalized setting. A layered lattice can be seen as lattices where certain directions have infinite weight. It can also be
Basis reduction for layered lattices
E.L. Torreão Dassen (Erwin)
2011-01-01
htmlabstractWe develop the theory of layered Euclidean spaces and layered lattices. With this new theory certain problems that usually are solved by using classical lattices with a "weighting" gain a new, more natural form. Using the layered lattice basis reduction algorithms introduced here these
Parity effect of bipolar quantum Hall edge transport around graphene antidots.
Matsuo, Sadashige; Nakaharai, Shu; Komatsu, Katsuyoshi; Tsukagoshi, Kazuhito; Moriyama, Takahiro; Ono, Teruo; Kobayashi, Kensuke
2015-06-30
Parity effect, which means that even-odd property of an integer physical parameter results in an essential difference, ubiquitously appears and enables us to grasp its physical essence as the microscopic mechanism is less significant in coarse graining. Here we report a new parity effect of quantum Hall edge transport in graphene antidot devices with pn junctions (PNJs). We found and experimentally verified that the bipolar quantum Hall edge transport is drastically affected by the parity of the number of PNJs. This parity effect is universal in bipolar quantum Hall edge transport of not only graphene but also massless Dirac electron systems. These results offer a promising way to design electron interferometers in graphene.
An alternative lattice field theory formulation inspired by lattice supersymmetry
D'Adda, Alessandro; Kawamoto, Noboru; Saito, Jun
2017-12-01
We propose an unconventional formulation of lattice field theories which is quite general, although originally motivated by the quest of exact lattice supersymmetry. Two long standing problems have a solution in this context: 1) Each degree of freedom on the lattice corresponds to 2 d degrees of freedom in the continuum, but all these doublers have (in the case of fermions) the same chirality and can be either identified, thus removing the degeneracy, or, in some theories with extended supersymmetry, identified with different members of the same supermultiplet. 2) The derivative operator, defined on the lattice as a suitable periodic function of the lattice momentum, is an addittive and conserved quantity, thus assuring that the Leibniz rule is satisfied. This implies that the product of two fields on the lattice is replaced by a non-local "star product" which is however in general non-associative. Associativity of the "star product" poses strong restrictions on the form of the lattice derivative operator (which becomes the inverse Gudermannian function of the lattice momentum) and has the consequence that the degrees of freedom of the lattice theory and of the continuum theory are in one-to-one correspondence, so that the two theories are eventually equivalent. We can show that the non-local star product of the fields effectively turns into a local one in the continuum limit. Regularization of the ultraviolet divergences on the lattice is not associated to the lattice spacing, which does not act as a regulator, but may be obtained by a one parameter deformation of the lattice derivative, thus preserving the lattice structure even in the limit of infinite momentum cutoff. However this regularization breaks gauge invariance and a gauge invariant regularization within the lattice formulation is still lacking.
Managing Workplace Incivility: The Role of Conflict Management Styles--Antecedent or Antidote?
Trudel, Jeannie; Reio, Thomas G., Jr.
2011-01-01
The workforce of the 21st century is dealing with rapid changes and increased competition across industries. Such changes place stress on management and workers alike, increasing the potential for workplace conflict and deviant workplace behaviors, including incivility. The importance of effective conflict management in the workplace has been…
Humanistic Antidotes to Social Media/Cell Phone Addiction in the College Classroom
Directory of Open Access Journals (Sweden)
Elliot Benjamin
2016-08-01
Full Text Available This article describes “humanistic antidotes” to offset the widespread social media/cell phone addiction prevalent in current US college classrooms. The inappropriate use of cell phones to engage in social media in college classrooms is a pervasive problem that many college instructors have complained about. The dominant focus of this article is in humanistic education, in which the author's efforts at getting psychology college students to put away their cell phones, “talk with each other,” and gain awareness of the detrimental effects of social media addiction and narcissism is illustrated. The methodology utilized in this article is based upon autoethnographic research, where relevant experiences of the researcher are considered to be an informative and fundamental part of the research. The author describes in narrative form his relevant experiences in formulating humanistic antidotes to the excessive and inappropriate use of cell phones to engage in social media, that he encountered in his college psychology teaching. These humanistic antidotes are described as a three-step process: 1 take necessary actions to eliminate as much as possible the inappropriate use of cell phones in the classroom; 2 engage students in required personal/academic small group discussions every class period; 3 include small discussions about the excessive and inappropriate use of cell phones and social media, and require them to write and present project papers of their own choosing, which will likely include some papers on the topic of cell phone/social media addiction, demonstrating their awareness of the detrimental aspects of this pervasive problem.
International Nuclear Information System (INIS)
Borsanyi, Sz.; Kampert, K.H.; Fodor, Z.; Forschungszentrum Juelich; Eoetvoes Univ., Budapest
2016-06-01
We present a full result for the equation of state (EoS) in 2+1+1 (up/down, strange and charm quarks are present) flavour lattice QCD. We extend this analysis and give the equation of state in 2+1+1+1 flavour QCD. In order to describe the evolution of the universe from temperatures several hundreds of GeV to the MeV scale we also include the known effects of the electroweak theory and give the effective degree of freedoms. As another application of lattice QCD we calculate the topological susceptibility (χ) up to the few GeV temperature region. These two results, EoS and χ, can be used to predict the dark matter axion's mass in the post-inflation scenario and/or give the relationship between the axion's mass and the universal axionic angle, which acts as a initial condition of our universe.
Energy Technology Data Exchange (ETDEWEB)
Buechner, O. [Zentralinstitut fuer Angewandte Mathematik ZAM, 52425 Juelich (Germany); Ernst, M. [Deutsches Elektronen-Synchrotron DESY, 22603 Hamburg (Germany); Jansen, K. [John von Neumann-Institut fuer Computing NIC/DESY, 15738 Zeuthen (Germany); Lippert, Th. [Zentralinstitut fuer Angewandte Mathematik ZAM, 52425 Juelich (Germany); Melkumyan, D. [Deutsches Elektronen-Synchrotron DESY, 15738 Zeuthen (Germany); Orth, B. [Zentralinstitut fuer Angewandte Mathematik ZAM, 52425 Juelich (Germany); Pleiter, D. [John von Neumann-Institut fuer Computing NIC/DESY, 15738 Zeuthen (Germany)]. E-mail: dirk.pleiter@desy.de; Stueben, H. [Konrad-Zuse-Institut fuer Informationstechnik ZIB, 14195 Berlin (Germany); Wegner, P. [Deutsches Elektronen-Synchrotron DESY, 15738 Zeuthen (Germany); Wollny, S. [Konrad-Zuse-Institut fuer Informationstechnik ZIB, 14195 Berlin (Germany)
2006-04-01
As the need for computing resources to carry out numerical simulations of Quantum Chromodynamics (QCD) formulated on a lattice has increased significantly, efficient use of the generated data has become a major concern. To improve on this, groups plan to share their configurations on a worldwide level within the International Lattice DataGrid (ILDG). Doing so requires standardized description of the configurations, standards on binary file formats and common middleware interfaces. We describe the requirements and problems, and discuss solutions. Furthermore, an overview is given on the implementation of the LatFor DataGrid [http://www-zeuthen.desy.de/latfor/ldg], a France/German/Italian grid that will be one of the regional grids within the ILDG grid-of-grids concept.
Energy Technology Data Exchange (ETDEWEB)
Gupta, R.
1998-12-31
The goal of the lectures on lattice QCD (LQCD) is to provide an overview of both the technical issues and the progress made so far in obtaining phenomenologically useful numbers. The lectures consist of three parts. The author`s charter is to provide an introduction to LQCD and outline the scope of LQCD calculations. In the second set of lectures, Guido Martinelli will discuss the progress they have made so far in obtaining results, and their impact on Standard Model phenomenology. Finally, Martin Luescher will discuss the topical subjects of chiral symmetry, improved formulation of lattice QCD, and the impact these improvements will have on the quality of results expected from the next generation of simulations.
Jipsen, Peter
1992-01-01
The study of lattice varieties is a field that has experienced rapid growth in the last 30 years, but many of the interesting and deep results discovered in that period have so far only appeared in research papers. The aim of this monograph is to present the main results about modular and nonmodular varieties, equational bases and the amalgamation property in a uniform way. The first chapter covers preliminaries that make the material accessible to anyone who has had an introductory course in universal algebra. Each subsequent chapter begins with a short historical introduction which sites the original references and then presents the results with complete proofs (in nearly all cases). Numerous diagrams illustrate the beauty of lattice theory and aid in the visualization of many proofs. An extensive index and bibliography also make the monograph a useful reference work.
Lattices of dielectric resonators
Trubin, Alexander
2016-01-01
This book provides the analytical theory of complex systems composed of a large number of high-Q dielectric resonators. Spherical and cylindrical dielectric resonators with inferior and also whispering gallery oscillations allocated in various lattices are considered. A new approach to S-matrix parameter calculations based on perturbation theory of Maxwell equations, developed for a number of high-Q dielectric bodies, is introduced. All physical relationships are obtained in analytical form and are suitable for further computations. Essential attention is given to a new unified formalism of the description of scattering processes. The general scattering task for coupled eigen oscillations of the whole system of dielectric resonators is described. The equations for the expansion coefficients are explained in an applicable way. The temporal Green functions for the dielectric resonator are presented. The scattering process of short pulses in dielectric filter structures, dielectric antennas and lattices of d...
International Nuclear Information System (INIS)
1962-01-01
The panel was attended by prominent physicists from most of the well-known laboratories in the field of light-water lattices, who exchanged the latest information on the status of work in their countries and discussed both the theoretical and the experimental aspects of the subjects. The supporting papers covered most problems, including criticality, resonance absorption, thermal utilization, spectrum calculations and the physics of plutonium bearing systems. Refs, figs and tabs
International Nuclear Information System (INIS)
Bowler, Ken
1990-01-01
One of the major recent developments in particle theory has been the use of very high performance computers to obtain approximate numerical solutions of quantum field theories by formulating them on a finite space-time lattice. The great virtue of this new technique is that it avoids the straitjacket of perturbation theory and can thus attack new, but very fundamental problems, such as the calculation of hadron masses in quark-gluon field theory (quantum chromodynamics - QCD)
Automated lattice data generation
Directory of Open Access Journals (Sweden)
Ayyar Venkitesh
2018-01-01
Full Text Available The process of generating ensembles of gauge configurations (and measuring various observables over them can be tedious and error-prone when done “by hand”. In practice, most of this procedure can be automated with the use of a workflow manager. We discuss how this automation can be accomplished using Taxi, a minimal Python-based workflow manager built for generating lattice data. We present a case study demonstrating this technology.
Adamatzky, Andrew
2015-01-01
The book gives a comprehensive overview of the state-of-the-art research and engineering in theory and application of Lattice Automata in design and control of autonomous Robots. Automata and robots share the same notional meaning. Automata (originated from the latinization of the Greek word “αυτόματον”) as self-operating autonomous machines invented from ancient years can be easily considered the first steps of robotic-like efforts. Automata are mathematical models of Robots and also they are integral parts of robotic control systems. A Lattice Automaton is a regular array or a collective of finite state machines, or automata. The Automata update their states by the same rules depending on states of their immediate neighbours. In the context of this book, Lattice Automata are used in developing modular reconfigurable robotic systems, path planning and map exploration for robots, as robot controllers, synchronisation of robot collectives, robot vision, parallel robotic actuators. All chapters are...
Dielectric lattice gauge theory
International Nuclear Information System (INIS)
Mack, G.
1983-06-01
Dielectric lattice gauge theory models are introduced. They involve variables PHI(b)epsilong that are attached to the links b = (x+esub(μ),x) of the lattice and take their values in the linear space g which consists of real linear combinations of matrices in the gauge group G. The polar decomposition PHI(b)=U(b)osub(μ)(x) specifies an ordinary lattice gauge field U(b) and a kind of dielectric field epsilonsub(ij)proportionalosub(i)osub(j)sup(*)deltasub(ij). A gauge invariant positive semidefinite kinetic term for the PHI-field is found, and it is shown how to incorporate Wilson fermions in a way which preserves Osterwalder Schrader positivity. Theories with G = SU(2) and without matter fields are studied in some detail. It is proved that confinement holds, in the sense that Wilson loop expectation values show an area law decay, if the Euclidean action has certain qualitative features which imply that PHI = 0 (i.e. dielectric field identical 0) is the unique maximum of the action. (orig.)
Toward lattice fractional vector calculus
Tarasov, Vasily E.
2014-09-01
An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity.
International Nuclear Information System (INIS)
Vidovsky, I.; Kereszturi, A.
1991-11-01
The results of experiments and calculations on Gd lattices are presented, and a comparison of experimental and calculational data is given. This latter can be divided into four groups. The first belongs to the comparison of criticality parameters, the second group is related with the comparison of 2D distributions, the third one relates the comparison of intra-macrocell distributions, whereas the fourth group is devoted for the comparison of spectral parameters. For comparison, the computer code RFIT based on strict statistical criteria has been used. The calculated and measured results agree, in most cases, sufficiently. (R.P.) 11 refs.; 13 figs.; 9 tabs
Lattice Vibrations in Chlorobenzenes:
DEFF Research Database (Denmark)
Reynolds, P. A.; Kjems, Jørgen; White, J. W.
1974-01-01
Lattice vibrational dispersion curves for the ``intermolecular'' modes in the triclinic, one molecule per unit cell β phase of p‐C6D4Cl2 and p‐C6H4Cl2 have been obtained by inelastic neutron scattering. The deuterated sample was investigated at 295 and at 90°K and a linear extrapolation to 0°K...... was applied in order to correct for anharmonic effects. Calculations based on the atom‐atom model for van der Waals' interaction and on general potential parameters for the aromatic compounds agree reasonably well with the experimental observations. There is no substantial improvement in fit obtained either...
Lattice of quantum predictions
Drieschner, Michael
1993-10-01
What is the structure of reality? Physics is supposed to answer this question, but a purely empiristic view is not sufficient to explain its ability to do so. Quantum mechanics has forced us to think more deeply about what a physical theory is. There are preconditions every physical theory must fulfill. It has to contain, e.g., rules for empirically testable predictions. Those preconditions give physics a structure that is “a priori” in the Kantian sense. An example is given how the lattice structure of quantum mechanics can be understood along these lines.
Drashkovicheva, Kh; Igoshin, V I; Katrinyak, T; Kolibiar, M
1989-01-01
This book is another publication in the recent surveys of ordered sets and lattices. The papers, which might be characterized as "reviews of reviews," are based on articles reviewed in the Referativnyibreve Zhurnal: Matematika from 1978 to 1982. For the sake of completeness, the authors also attempted to integrate information from other relevant articles from that period. The bibliography of each paper provides references to the reviews in RZhMat and Mathematical Reviews where one can seek more detailed information. Specifically excluded from consideration in this volume were such topics as al
Lattice cell burnup calculation
International Nuclear Information System (INIS)
Pop-Jordanov, J.
1977-01-01
Accurate burnup prediction is a key item for design and operation of a power reactor. It should supply information on isotopic changes at each point in the reactor core and the consequences of these changes on the reactivity, power distribution, kinetic characters, control rod patterns, fuel cycles and operating strategy. A basic stage in the burnup prediction is the lattice cell burnup calculation. This series of lectures attempts to give a review of the general principles and calculational methods developed and applied in this area of burnup physics
Magnetization dynamics in artificial spin ice lattices
Heinonen, Olle; Gliga, Sebastian
2012-02-01
Artificial spin ice lattices (ASIL) consist of regular arrays of single-domain nanomagnets displaying ice rule ordering. Frustration is introduced through shape anisotropy. ASILs have been shown to exhibit complex behavior, with rich phase diagrams and quasi-static magnetization reversal. In particular, topological defects, such as Dirac monopoles and Dirac strings, play a fundamental role in the quasi-static behavior of ASILs. In this work, we use micromagnetic simulations to investigate the resonant frequencies of square lattice ASILs consisting of stadium-shaped nanomagnets. We calculate the evolution of the fundamental modes of a single element when elements are combined in four-stadia configurations and large lattices. In a cross-shaped four-stadium configuration for example, the Dirac monopole splits the frequencies of the lowest (near)-degenerate symmetric and antisymmetric edge modes of a single stadium. This splitting increases in a 24-stadium system with two monopoles. We also calculate the evolution of the spectral characteristics as the monopoles move farther apart in the lattice, but stay connected through a Dirac string. Our work suggests that these topological defects have distinct spectral signatures that can be detected experimentally.
Extreme lattices: symmetries and decorrelation
Andreanov, A.; Scardicchio, A.; Torquato, S.
2016-11-01
We study statistical and structural properties of extreme lattices, which are the local minima in the density landscape of lattice sphere packings in d-dimensional Euclidean space {{{R}}d} . Specifically, we ascertain statistics of the densities and kissing numbers as well as the numbers of distinct symmetries of the packings for dimensions 8 through 13 using the stochastic Voronoi algorithm. The extreme lattices in a fixed dimension of space d (d≥slant 8 ) are dominated by typical lattices that have similar packing properties, such as packing densities and kissing numbers, while the best and the worst packers are in the long tails of the distribution of the extreme lattices. We also study the validity of the recently proposed decorrelation principle, which has important implications for sphere packings in general. The degree to which extreme-lattice packings decorrelate as well as how decorrelation is related to the packing density and symmetry of the lattices as the space dimension increases is also investigated. We find that the extreme lattices decorrelate with increasing dimension, while the least symmetric lattices decorrelate faster.
Allgardsson, Anders; Berg, Lotta; Akfur, Christine; Hörnberg, Andreas; Worek, Franz; Linusson, Anna; Ekström, Fredrik J
2016-05-17
Organophosphorus nerve agents interfere with cholinergic signaling by covalently binding to the active site of the enzyme acetylcholinesterase (AChE). This inhibition causes an accumulation of the neurotransmitter acetylcholine, potentially leading to overstimulation of the nervous system and death. Current treatments include the use of antidotes that promote the release of functional AChE by an unknown reactivation mechanism. We have used diffusion trap cryocrystallography and density functional theory (DFT) calculations to determine and analyze prereaction conformers of the nerve agent antidote HI-6 in complex with Mus musculus AChE covalently inhibited by the nerve agent sarin. These analyses reveal previously unknown conformations of the system and suggest that the cleavage of the covalent enzyme-sarin bond is preceded by a conformational change in the sarin adduct itself. Together with data from the reactivation kinetics, this alternate conformation suggests a key interaction between Glu202 and the O-isopropyl moiety of sarin. Moreover, solvent kinetic isotope effect experiments using deuterium oxide reveal that the reactivation mechanism features an isotope-sensitive step. These findings provide insights into the reactivation mechanism and provide a starting point for the development of improved antidotes. The work also illustrates how DFT calculations can guide the interpretation, analysis, and validation of crystallographic data for challenging reactive systems with complex conformational dynamics.
Kassa, Jiri; Pohanka, Miroslav; Timperley, Christopher M; Bird, Mike; Green, A Christopher; Tattersall, John E H
2016-06-01
The potency of the bispyridinium non-oxime compound MB327 [1,1'-(propane-1,3-diyl)bis(4-tert-butylpyridinium) diiodide] to increase the therapeutic efficacy of the standard antidotal treatment (atropine in combination with an oxime) of acute poisoning with organophosphorus nerve agents was studied in vivo. The therapeutic efficacy of atropine alone - or atropine in combination with an oxime, MB327, or both an oxime and MB237 - was evaluated by the determination of LD50 values of several nerve agents (tabun, sarin and soman) in mice with and without treatment. The addition of MB327 increased the therapeutic efficacy of atropine alone, and atropine in combination with an oxime, against all three nerve agents, although differences in the LD50 values only reached statistical significance for sarin. In conclusion, the addition of the compound MB327 to the standard antidotal treatment of acute poisonings with nerve agents was beneficial regardless of the chemical structure of the nerve agent, although at the dose employed, MB327 in combination with atropine, or atropine and an oxime, provided only a modest increase in protection ratio. These results from mice, and previous ones from guinea-pigs, provide consistent evidence for additional, albeit modest, efficacy resulting from the inclusion of the antinicotinic compound MB327 in standard antidotal therapy. Given the typically steep probit slope for the dose-lethality relationship for nerve agents, such modest increases in protection ratio could provide significant survival benefit.
Elimination of spurious lattice fermion solutions and noncompact lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Lee, T.D.
1997-09-22
It is well known that the Dirac equation on a discrete hyper-cubic lattice in D dimension has 2{sup D} degenerate solutions. The usual method of removing these spurious solutions encounters difficulties with chiral symmetry when the lattice spacing l {ne} 0, as exemplified by the persistent problem of the pion mass. On the other hand, we recall that in any crystal in nature, all the electrons do move in a lattice and satisfy the Dirac equation; yet there is not a single physical result that has ever been entangled with a spurious fermion solution. Therefore it should not be difficult to eliminate these unphysical elements. On a discrete lattice, particle hop from point to point, whereas in a real crystal the lattice structure in embedded in a continuum and electrons move continuously from lattice cell to lattice cell. In a discrete system, the lattice functions are defined only on individual points (or links as in the case of gauge fields). However, in a crystal the electron state vector is represented by the Bloch wave functions which are continuous functions in {rvec {gamma}}, and herein lies one of the essential differences.
Characterization of projection lattices of Hilbert spaces
Energy Technology Data Exchange (ETDEWEB)
Szambien, H.H.
1986-09-01
The classical lattices of projections of Hilbert spaces over the real, the complex or the quaternion number field are characterized among the totality of irreducible, complete, orthomodular, atomic lattices satisfying the covering property. To this end, so-called paratopological lattices are introduced, i.e, lattices carrying a topology that renders the lattice operations restrictedly continuous.
Lepik, Katherine J; Levy, Adrian R; Sobolev, Boris G; Purssell, Roy A; DeWitt, Christopher R; Erhardt, Gunnar D; Kennedy, James R; Daws, Derek E; Brignall, Jane L
2009-04-01
We investigate adverse drug events associated with antidotes ethanol and fomepizole in methanol or ethylene glycol poisonings. An "adverse drug event" is harm associated with normal or incorrect drug use. We describe type, frequency, severity, seriousness, and onset time of adverse drug events and test the hypothesis that fomepizole results in fewer adverse drug events than ethanol. This cohort study included patients aged 13 years or older, hospitalized between 1996 and 2005 for methanol or ethylene glycol poisoning (identified by International Classification of Diseases, Ninth Revision or 10th Revision codes) and treated with at least 1 dose of ethanol or fomepizole. Two abstractors separately reviewed each chart, identifying new clinical events during antidote treatment. Three toxicologists determined, by consensus, which events were adverse drug events. The primary outcome was at least 1 adverse drug event, expressed as adverse drug event rate per person-day of antidote treatment. Association between time to first adverse drug event and antidote type was modeled by Cox regression, adjusted for confounders. Two hundred twenty-three charts were reviewed and 172 analyzed. Toxicologists identified at least 1 adverse drug event in 74 of 130 (57%) ethanol-treated and 5 of 42 (12%) fomepizole-treated cases. Central nervous system symptoms accounted for most adverse drug events (48% ethanol-treated, 2% fomepizole-treated). Severe adverse drug events occurred in 26 of 130 (20%) ethanol-treated (coma, extreme agitation, cardiovascular) and 2 of 42 (5%) fomepizole-treated (coma, cardiovascular). Serious (life-threatening) adverse drug events occurred in 11 of 130 (8%) ethanol-treated (respiratory depression, hypotension) and 1 of 42 (2%) fomepizole-treated (hypotension, bradycardia) cases. Median adverse drug event onset was within 3 hours after the start of either antidote. Ethanol and fomepizole adverse drug event rates were 0.93 and 0.13 adverse drug events per
Nanometric MIL-125-NH2 Metal–Organic Framework as a Potential Nerve Agent Antidote Carrier
Vilela, Sérgio M. F.; Salcedo-Abraira, Pablo; Colinet, Isabelle; Salles, Fabrice; Serre, Christian; Horcajada, Patricia
2017-01-01
The three-dimensional (3D) microporous titanium aminoterephthalate MIL-125-NH2 (MIL: Material of Institut Lavoisier) was successfully isolated as monodispersed nanoparticles, which are compatible with intravenous administration, by using a simple, safe and low-cost synthetic approach (100 °C/32 h under atmospheric pressure) so that for the first time it could be considered for encapsulation and the release of drugs. The nerve agent antidote 2-[(hydroxyimino)methyl]-1-methyl-pyridinium chloride (2-PAM or pralidoxime) was effectively encapsulated into the pores of MIL-125-NH2 as a result of the interactions between 2-PAM and the pore walls being mediated by π-stacking and hydrogen bonds, as deduced from infrared spectroscopy and Monte Carlo simulation studies. Finally, colloidal solutions of MIL-125-NH2 nanoparticles exhibited remarkable stability in different organic media, aqueous solutions at different pH and under relevant physiological conditions over time (24 h). 2-PAM was rapidly released from the pores of MIL-125-NH2 in vitro. PMID:29023426
Nanometric MIL-125-NH₂ Metal-Organic Framework as a Potential Nerve Agent Antidote Carrier.
Vilela, Sérgio M F; Salcedo-Abraira, Pablo; Colinet, Isabelle; Salles, Fabrice; de Koning, Martijn C; Joosen, Marloes J A; Serre, Christian; Horcajada, Patricia
2017-10-12
The three-dimensional (3D) microporous titanium aminoterephthalate MIL-125-NH₂ (MIL: Material of Institut Lavoisier) was successfully isolated as monodispersed nanoparticles, which are compatible with intravenous administration, by using a simple, safe and low-cost synthetic approach (100 °C/32 h under atmospheric pressure) so that for the first time it could be considered for encapsulation and the release of drugs. The nerve agent antidote 2-[(hydroxyimino)methyl]-1-methyl-pyridinium chloride (2-PAM or pralidoxime) was effectively encapsulated into the pores of MIL-125-NH₂ as a result of the interactions between 2-PAM and the pore walls being mediated by π-stacking and hydrogen bonds, as deduced from infrared spectroscopy and Monte Carlo simulation studies. Finally, colloidal solutions of MIL-125-NH₂ nanoparticles exhibited remarkable stability in different organic media, aqueous solutions at different pH and under relevant physiological conditions over time (24 h). 2-PAM was rapidly released from the pores of MIL-125-NH₂ in vitro.
Human butyrylcholinesterase as a general scavenging antidote for nerve agents toxicity
Energy Technology Data Exchange (ETDEWEB)
Ashani, Y.; Grunwald, J.; Grauer, E.; Brandeis, R.; Cohen, E.
1993-05-13
Butyrylcholinesterase purified from human plasma (HuBChE) was evaluated both in vitro and in vivo as a single prophylactic antidote against multiples of i.v. LD(50) doses of nerve agents (NA) (GA, GB, GD, and VX). Significant therapeutic concentrations of HuBChE were observed in blood even 48 hrs following either i.v. or i.m. injection in mice, rats, guinea pigs, and monkeys. High levels of protection were also demonstrated in a small number of animals exposed to GD vapors. The stoichiometry of the in vivo sequestration of the anti-ChE toxicants was consistent with HuBChE/NA ratio of the molar concentration required to inhibit 100% enzyme activity in vitro. Further, linear correlation was demonstrated between blood level of HuBChE and the extent of protection obtained against the toxicity of NA. It was estimated that in order to obtain reasonable protection, exogenously administered HuBChE should be able to reduce the concentration of the NA to a level below its LD(50) value within less than one blood circulation time. HuBChE significantly prevented GD-induced behavioral deficits. The enzyme itself did not alter performance of cognitive tasks. Thus, HuBChE not only increased survival after NA exposure, but also alleviated post exposure symptoms. without the need for any additional therapeutic drugs (e. g., atropine, pralidoxime chloride, diazepam).
Hydroxypyri(mi)dine-based chelators as antidotes of toxicity due to aluminum and actinides.
Santos, M A; Esteves, M A; Chaves, S
2012-01-01
This review is focused on recent developments on hydroxypyri(mi)dines, as aluminum and actinide chelating agents to combat the toxicity due to accumulations of these metal ions in human body resulting from excessive metal exposure. After a brief update revision of the most common processes of aluminum (Al) exposure, as well as the associated toxicities and pathologies, we will focus on the current available Al chelators and future perspective as potential antidotes of Al toxicity. Due to the similarity between Al and Fe, a major emphasis is given to the hydroxypyridinone and hydroxypyrimidinone chelators, since they are analogues of the current iron chelators in clinical use (DFP and DFO). This review includes issues such as molecular design strategies and corresponding effects on the associated physico-chemical properties, lipo-hydrophilic balance, toxicity, in vivo bioassays and current clinical applications. The hydroxypyri(mi)dine chelators are also suitable for other hard metal ions, such as the radiotoxic actinides, and so a brief review is included on the applications of these chelators in actinides scavenging.
Nanometric MIL-125-NH2 Metal–Organic Framework as a Potential Nerve Agent Antidote Carrier
Directory of Open Access Journals (Sweden)
Sérgio M. F. Vilela
2017-10-01
Full Text Available The three-dimensional (3D microporous titanium aminoterephthalate MIL-125-NH2 (MIL: Material of Institut Lavoisier was successfully isolated as monodispersed nanoparticles, which are compatible with intravenous administration, by using a simple, safe and low-cost synthetic approach (100 °C/32 h under atmospheric pressure so that for the first time it could be considered for encapsulation and the release of drugs. The nerve agent antidote 2-[(hydroxyiminomethyl]-1-methyl-pyridinium chloride (2-PAM or pralidoxime was effectively encapsulated into the pores of MIL-125-NH2 as a result of the interactions between 2-PAM and the pore walls being mediated by π-stacking and hydrogen bonds, as deduced from infrared spectroscopy and Monte Carlo simulation studies. Finally, colloidal solutions of MIL-125-NH2 nanoparticles exhibited remarkable stability in different organic media, aqueous solutions at different pH and under relevant physiological conditions over time (24 h. 2-PAM was rapidly released from the pores of MIL-125-NH2 in vitro.
Memory load as a cognitive antidote to performance decrements in data entry.
Chapman, Mary J; Healy, Alice F; Kole, James A
2016-10-01
In two experiments, subjects trained in data entry, typing one 4-digit number at a time. At training, subjects either typed the numbers immediately after they appeared (immediate) or typed the previous number from memory while viewing the next number (delayed). In Experiment 2 stimulus presentation time was limited and either nothing or a space (gap) was inserted between the second and third digits. In both experiments after training, all subjects completed a test with no gap and typed numbers immediately. Training with a memory load improved speed across training blocks (Experiment 1) and eliminated the decline in accuracy across training blocks (Experiment 2), thus serving as a cognitive antidote to performance decrements. An analysis of each keystroke revealed different underlying processes and strategies for the two training conditions, including when encoding took place. Chunking (in which the first and last two digits are treated separately) was more evident in the immediate than in the delayed condition and was exaggerated with a gap, even at test when there was no gap. These results suggest that such two-digit chunking is due to stimulus encoding and motor planning processes as well as memory, and those processes transferred from training to testing.
Lattices, supersymmetry and Kaehler fermions
International Nuclear Information System (INIS)
Scott, D.M.
1984-01-01
It is shown that a graded extension of the space group of a (generalised) simple cubic lattice exists in any space dimension, D. The fermionic variables which arise admit a Kaehlerian interpretation. Each graded space group is a subgroup of a graded extension of the appropriate Euclidean group, E(D). The relevance of this to the construction of lattice theories is discussed. (author)
Fast simulation of lattice systems
DEFF Research Database (Denmark)
Bohr, H.; Kaznelson, E.; Hansen, Frank
1983-01-01
A new computer system with an entirely new processor design is described and demonstrated on a very small trial lattice. The new computer simulates systems of differential equations of the order of 104 times faster than present day computers and we describe how the machine can be applied to lattice...
Quantum phases in optical lattices
Dickerscheid, Dennis Brian Martin
2006-01-01
An important new development in the field of ultracold atomic gases is the study of the properties of these gases in a so-called optical lattice. An optical lattice is a periodic trapping potential for the atoms that is formed by the interference pattern of a few laser beams. A reason for the
Lattice gauge theory: Present status
International Nuclear Information System (INIS)
Creutz, M.
1993-09-01
Lattice gauge theory is our primary tool for the study of non- perturbative phenomena in hadronic physics. In addition to giving quantitative information on confinement, the approach is yielding first principles calculations of hadronic spectra and matrix elements. After years of confusion, there has been significant recent progress in understanding issues of chiral symmetry on the lattice
Geometry of lattice field theory
International Nuclear Information System (INIS)
Honan, T.J.
1986-01-01
Using some tools of algebraic topology, a general formalism for lattice field theory is presented. The lattice is taken to be a simplicial complex that is also a manifold and is referred to as a simplicial manifold. The fields on this lattice are cochains, that are called lattice forms to emphasize the connections with differential forms in the continuum. This connection provides a new bridge between lattice and continuum field theory. A metric can be put onto this simplicial manifold by assigning lengths to every link or I-simplex of the lattice. Regge calculus is a way of defining general relativity on this lattice. A geometric discussion of Regge calculus is presented. The Regge action, which is a discrete form of the Hilbert action, is derived from the Hilbert action using distribution valued forms. This is a new derivation that emphasizes the underlying geometry. Kramers-Wannier duality in statistical mechanics is discussed in this general setting. Nonlinear field theories, which include gauge theories and nonlinear sigma models are discussed in the continuum and then are put onto a lattice. The main new result here is the generalization to curved spacetime, which consists of making the theory compatible with Regge calculus
Constraint percolation on hyperbolic lattices
Lopez, Jorge H.; Schwarz, J. M.
2017-11-01
Hyperbolic lattices interpolate between finite-dimensional lattices and Bethe lattices, and they are interesting in their own right, with ordinary percolation exhibiting not one but two phase transitions. We study four constraint percolation models—k -core percolation (for k =1 ,2 ,3 ) and force-balance percolation—on several tessellations of the hyperbolic plane. By comparing these four different models, our numerical data suggest that all of the k -core models, even for k =3 , exhibit behavior similar to ordinary percolation, while the force-balance percolation transition is discontinuous. We also provide proof, for some hyperbolic lattices, of the existence of a critical probability that is less than unity for the force-balance model, so that we can place our interpretation of the numerical data for this model on a more rigorous footing. Finally, we discuss improved numerical methods for determining the two critical probabilities on the hyperbolic lattice for the k -core percolation models.
Lattice quantum chromodynamics practical essentials
Knechtli, Francesco; Peardon, Michael
2017-01-01
This book provides an overview of the techniques central to lattice quantum chromodynamics, including modern developments. The book has four chapters. The first chapter explains the formulation of quarks and gluons on a Euclidean lattice. The second chapter introduces Monte Carlo methods and details the numerical algorithms to simulate lattice gauge fields. Chapter three explains the mathematical and numerical techniques needed to study quark fields and the computation of quark propagators. The fourth chapter is devoted to the physical observables constructed from lattice fields and explains how to measure them in simulations. The book is aimed at enabling graduate students who are new to the field to carry out explicitly the first steps and prepare them for research in lattice QCD.
Lattice Location of Transition Metals in Semiconductors
2002-01-01
%IS366 %title\\\\ \\\\Transition metals (TMs) in semiconductors have been the subject of considerable research for nearly 40 years. This is due both to their role as important model impurities for deep centers in semiconductors, and to their technological impact as widespread contaminants in Si processing, where the miniaturization of devices requires to keep their sheet concentration below 10$^{10}$ cm$^{-2}$. As a consequence of the low TM solubility, conventional ion beam methods for direct lattice location have failed completely in identifying the lattice sites of isolated transition metals. Although electron paramagnetic resonance (EPR) has yielded valuable information on a variety of TM centers, it has been unable to detect certain defects considered by theory, e.g., isolated interstitial or substitutional Cu in Si. The proposed identity of other EPR centers such as substitutional Fe in Si, still needs confirmation by additional experimental methods. As a consequence, the knowledge on the structural propert...
Toward lattice fractional vector calculus
International Nuclear Information System (INIS)
Tarasov, Vasily E
2014-01-01
An analog of fractional vector calculus for physical lattice models is suggested. We use an approach based on the models of three-dimensional lattices with long-range inter-particle interactions. The lattice analogs of fractional partial derivatives are represented by kernels of lattice long-range interactions, where the Fourier series transformations of these kernels have a power-law form with respect to wave vector components. In the continuum limit, these lattice partial derivatives give derivatives of non-integer order with respect to coordinates. In the three-dimensional description of the non-local continuum, the fractional differential operators have the form of fractional partial derivatives of the Riesz type. As examples of the applications of the suggested lattice fractional vector calculus, we give lattice models with long-range interactions for the fractional Maxwell equations of non-local continuous media and for the fractional generalization of the Mindlin and Aifantis continuum models of gradient elasticity. (papers)
Anderson localization in bipartite lattices
International Nuclear Information System (INIS)
Fabrizio, Michele; Castellani, Claudio
2000-01-01
We study the localization properties of a disordered tight-binding Hamiltonian on a generic bipartite lattice close to the band center. By means of a fermionic replica trick method, we derive the effective non-linear σ-model describing the diffusive modes, which we analyse by using the Wilson-Polyakov renormalization group. In addition to the standard parameters which define the non-linear σ-model, namely, the conductance and the external frequency, a new parameter enters, which may be related to the fluctuations of the staggered density of states. We find that, when both the regular hopping and the disorder only couple one sublattice to the other, the quantum corrections to the Kubo conductivity vanish at the band center, thus implying the existence of delocalized states. In two dimensions, the RG equations predict that the conductance flows to a finite value, while both the density of states and the staggered density of states fluctuations diverge. In three dimensions, we find that, sufficiently close to the band center, all states are extended, independently of the disorder strength. We also discuss the role of various symmetry breaking terms, as a regular hopping between same sublattices, or an on-site disorder
Anderson localization in bipartite lattices
International Nuclear Information System (INIS)
Fabrizio, M.; Castellani, C.
2000-04-01
We study the localization properties of a disordered tight-binding Hamiltonian on a generic bipartite lattice close to the band center. By means of a fermionic replica trick method, we derive the effective non-linear σ-model describing the diffusive modes, which we analyse by using the Wilson-Polyakov renormalization group. In addition to the standard parameters which define the non-linear σ-model, namely the conductance and the external frequency, a new parameter enters, which may be related to the fluctuations of the staggered density of states. We find that, when both the regular hopping and the disorder only couple one sublattice to the other, the quantum corrections to the Kubo conductivity vanish at the band center, thus implying the existence of delocalized states. In two dimensions, the RG equations predict that the conductance flows to a finite value, while both the density of states and the staggered density of states fluctuations diverge. In three dimensions, we find that, sufficiently close to the band center, all states are extended, independently of the disorder strength. We also discuss the role of various symmetry breaking terms, as a regular hopping between same sublattices, or an on-site disorder. (author)
Introduction to lattice gauge theory
International Nuclear Information System (INIS)
Gupta, R.
1987-01-01
The lattice formulation of Quantum Field Theory (QFT) can be exploited in many ways. We can derive the lattice Feynman rules and carry out weak coupling perturbation expansions. The lattice then serves as a manifestly gauge invariant regularization scheme, albeit one that is more complicated than standard continuum schemes. Strong coupling expansions: these give us useful qualitative information, but unfortunately no hard numbers. The lattice theory is amenable to numerical simulations by which one calculates the long distance properties of a strongly interacting theory from first principles. The observables are measured as a function of the bare coupling g and a gauge invariant cut-off ≅ 1/α, where α is the lattice spacing. The continuum (physical) behavior is recovered in the limit α → 0, at which point the lattice artifacts go to zero. This is the more powerful use of lattice formulation, so in these lectures the author focuses on setting up the theory for the purpose of numerical simulations to get hard numbers. The numerical techniques used in Lattice Gauge Theories have their roots in statistical mechanics, so it is important to develop an intuition for the interconnection between quantum mechanics and statistical mechanics. This will be the emphasis of the first lecture. In the second lecture, the author reviews the essential ingredients of formulating QCD on the lattice and discusses scaling and the continuum limit. In the last lecture the author summarizes the status of some of the main results. He also mentions the bottlenecks and possible directions for research. 88 refs
Lattice Methods for Quantum Chromodynamics
DeGrand, Thomas
2006-01-01
Numerical simulation of lattice-regulated QCD has become an important source of information about strong interactions. In the last few years there has been an explosion of techniques for performing ever more accurate studies on the properties of strongly interacting particles. Lattice predictions directly impact many areas of particle and nuclear physics theory and phenomenology. This book provides a thorough introduction to the specialized techniques needed to carry out numerical simulations of QCD: a description of lattice discretizations of fermions and gauge fields, methods for actually do
Localized structures in Kagome lattices
Energy Technology Data Exchange (ETDEWEB)
Saxena, Avadh B [Los Alamos National Laboratory; Bishop, Alan R [Los Alamos National Laboratory; Law, K J H [UNIV OF MASSACHUSETTS; Kevrekidis, P G [UNIV OF MASSACHUSETTS
2009-01-01
We investigate the existence and stability of gap vortices and multi-pole gap solitons in a Kagome lattice with a defocusing nonlinearity both in a discrete case and in a continuum one with periodic external modulation. In particular, predictions are made based on expansion around a simple and analytically tractable anti-continuum (zero coupling) limit. These predictions are then confirmed for a continuum model of an optically-induced Kagome lattice in a photorefractive crystal obtained by a continuous transformation of a honeycomb lattice.
Borwein, J M; McPhedran, R C
2013-01-01
The study of lattice sums began when early investigators wanted to go from mechanical properties of crystals to the properties of the atoms and ions from which they were built (the literature of Madelung's constant). A parallel literature was built around the optical properties of regular lattices of atoms (initiated by Lord Rayleigh, Lorentz and Lorenz). For over a century many famous scientists and mathematicians have delved into the properties of lattices, sometimes unwittingly duplicating the work of their predecessors. Here, at last, is a comprehensive overview of the substantial body of
John, Harald; Blum, Marc-Michael
2012-01-01
Pralidoxime (2-PAM) belongs to the class of monopyridinium oximes with reactivating potency on cholinesterases inhibited by phosphylating organophosphorus compounds (OPC), for example, pesticides and nerve agents. 2-PAM represents an established antidote for the therapy of anticholinesterase poisoning since the late 1950s. Quite high therapeutic concentrations in human plasma (about 13 µg/ml) lead to concentrations in urine being about 100 times higher allowing the use of less sensitive analytical techniques that were used especially in the early years after 2-PAM was introduced. In this time (mid-1950s until the end of the 1970s) 2-PAM was most often analyzed by either paper chromatography or simple UV spectroscopic techniques omitting any sample separation step. These methods were displaced completely after the establishment of column liquid chromatography in the early 1980s. Since then, diverse techniques including cation exchange, size-exclusion, reversed-phase, and ligand-exchange chromatography have been introduced. Today, the most popular method for 2-PAM quantification is ion pair chromatography often combined with UV detection representing more than 50% of all column chromatographic procedures published. Furthermore, electrophoretic approaches by paper and capillary zone electrophoresis have been successfully used but are seldom applied. This review provides a commentary and exhaustive summary of analytical techniques applied to detect 2-PAM in pharmaceutical formulations and biological samples to characterize stability and pharmacokinetics as well as decomposition and biotransformation products. Separation techniques as well as diverse detectors are discussed in appropriate detail allowing comparison of individual preferences and limitations. In addition, novel data on mass spectrometric fragmentation of 2-PAM are provided. Copyright © 2011 John Wiley & Sons, Ltd.
The Vitamin B12 Analog Cobinamide Is an Effective Antidote for Oral Cyanide Poisoning.
Lee, Jangwoen; Mahon, Sari B; Mukai, David; Burney, Tanya; Katebian, Behdod S; Chan, Adriano; Bebarta, Vikhyat S; Yoon, David; Boss, Gerry R; Brenner, Matthew
2016-12-01
Cyanide is a major chemical threat, and cyanide ingestion carries a higher risk for a supra-lethal dose exposure compared to inhalation but provides an opportunity for effective treatment due to a longer treatment window and a gastrointestinal cyanide reservoir that could be neutralized prior to systemic absorption. We hypothesized that orally administered cobinamide may function as a high-binding affinity scavenger and that gastric alkalinization would reduce cyanide absorption and concurrently increase cobinamide binding, further enhancing antidote effectiveness. Thirty New Zealand white rabbits were divided into five groups and were given a lethal dose of oral cyanide poisoning (50 mg). The survival time of animals was monitored with oral cyanide alone, oral cyanide with gastric alkalinization with oral sodium bicarbonate buffer (500 mg), and in combination with either aquohydroxocobinamide or dinitrocobinamide (250 mM). Red blood cell cyanide concentration, plasma cobinamide, and thiocyanate concentrations were measured from blood samples. In cyanide ingested animals, oral sodium bicarbonate alone significantly prolonged survival time to 20.3 ± 8.6 min compared to 10.5 ± 4.3 min in saline-treated controls, but did not lead to overall survival. Aquohydroxocobinamide and dinitrocobinamide increased survival time to 64 ± 41 (p cyanide concentration. Under all conditions, the plasma thiocyanate concentration gradually increased with time. This study demonstrates a promising new approach to treat high-dose cyanide ingestion, with gastric alkalinization alone and in combination with oral cobinamide for treating a supra-lethal dose of orally administered cyanide in rabbits.
DEFF Research Database (Denmark)
Zhu, Xiaolong; Wang, Weihua; Yan, Wei
2014-01-01
Nanostructured graphene on SiO2 substrates paves the way for enhanced light–matter interactions and explorations of strong plasmon–phonon hybridization in the mid-infrared regime. Unprecedented large-area graphene nanodot and antidot optical arrays are fabricated by nanosphere lithography......, with structural control down to the sub-100 nm regime. The interaction between graphene plasmon modes and the substrate phonons is experimentally demonstrated, and structural control is used to map out the hybridization of plasmons and phonons, showing coupling energies of the order 20 meV. Our findings...
Energy Technology Data Exchange (ETDEWEB)
DeGrand, T. [Univ. of Colorado, Boulder, CO (United States). Dept. of Physics
1997-06-01
These lectures provide an introduction to lattice methods for nonperturbative studies of Quantum Chromodynamics. Lecture 1: Basic techniques for QCD and results for hadron spectroscopy using the simplest discretizations; lecture 2: Improved actions--what they are and how well they work; lecture 3: SLAC physics from the lattice-structure functions, the mass of the glueball, heavy quarks and {alpha}{sub s} (M{sub z}), and B-{anti B} mixing. 67 refs., 36 figs.
Lattice Studies of Hyperon Spectroscopy
Energy Technology Data Exchange (ETDEWEB)
Richards, David G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-04-01
I describe recent progress at studying the spectrum of hadrons containing the strange quark through lattice QCD calculations. I emphasise in particular the richness of the spectrum revealed by lattice studies, with a spectrum of states at least as rich as that of the quark model. I conclude by prospects for future calculations, including in particular the determination of the decay amplitudes for the excited states.
Harmonic oscillator on a lattice
International Nuclear Information System (INIS)
Ader, J.P.; Bonnier, B.; Hontebeyrie, M.; Meyers, C.
1983-01-01
The continuum limit of the ground state energy for the harmonic oscillator with discrete time is derived for all possible choices of the lattice derivative. The occurrence of unphysical values is shown to arise whenever the lattice laplacian is not strictly positive on its Brillouin zone. These undesirable limits can either be finite and arbitrary (multiple spectrum) or infinite (overlapping sublattices with multiple spectrum). (orig.)
International Nuclear Information System (INIS)
DeGrand, T.
1997-01-01
These lectures provide an introduction to lattice methods for nonperturbative studies of Quantum Chromodynamics. Lecture 1: Basic techniques for QCD and results for hadron spectroscopy using the simplest discretizations; lecture 2: Improved actions--what they are and how well they work; lecture 3: SLAC physics from the lattice-structure functions, the mass of the glueball, heavy quarks and α s (M z ), and B-anti B mixing. 67 refs., 36 figs
Vortex lattice theory: A linear algebra approach
Chamoun, George C.
Vortex lattices are prevalent in a large class of physical settings that are characterized by different mathematical models. We present a coherent and generalized Hamiltonian fluid mechanics-based formulation that reduces all vortex lattices into a classic problem in linear algebra for a non-normal matrix A. Via Singular Value Decomposition (SVD), the solution lies in the null space of the matrix (i.e., we require nullity( A) > 0) as well as the distribution of its singular values. We demonstrate that this approach provides a good model for various types of vortex lattices, and makes it possible to extract a rich amount of information on them. The contributions of this thesis can be classified into four main points. The first is asymmetric equilibria. A 'Brownian ratchet' construct was used which converged to asymmetric equilibria via a random walk scheme that utilized the smallest singular value of A. Distances between configurations and equilibria were measured using the Frobenius norm ||·||F and 2-norm ||·||2, and conclusions were made on the density of equilibria within the general configuration space. The second contribution used Shannon Entropy, which we interpret as a scalar measure of the robustness, or likelihood of lattices to occur in a physical setting. Third, an analytic model was produced for vortex street patterns on the sphere by using SVD in conjunction with expressions for the center of vorticity vector and angular velocity. Equilibrium curves within the configuration space were presented as a function of the geometry, and pole vortices were shown to have a critical role in the formation and destruction of vortex streets. The fourth contribution entailed a more complete perspective of the streamline topology of vortex streets, linking the bifurcations to critical points on the equilibrium curves.
Homomorphisms of complete distributive lattices | Pultr ...
African Journals Online (AJOL)
A survey of analogous results on algebraic universality of categories based on finitary distributive (0, 1)-lattices is included to motivate further questions about categories based on complete distributive lattices. Keywords: complete distributive lattice, complete lattice homomorphism, frame, Heyting algebra, continuous map, ...
Energy Technology Data Exchange (ETDEWEB)
Perez-Junquera, A. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Martin, J.I. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain)]. E-mail: jmartin@condmat.uniovi.es; Anguita, J.V. [Instituto de Microelectronica de Madrid, CNM-CSIC, Isaac Newton 8, PTM, Tres Cantos, 28760 Madrid (Spain); Rodriguez-Rodriguez, G. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain) and Instituto Nacional del Carbon (INCAR), CSIC, c/Francisco Pintado Fe 26, 33011 Oviedo (Spain); Velez, M. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Rubio, H. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Alvarez-Prado, L.M. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain); Alameda, J.M. [Dpto. Fisica, Universidad de Oviedo, c/ Calvo Sotelo s/n, 33007 Oviedo (Spain)
2007-09-15
Diluted arrays of elliptical antidots have been fabricated by optical lithography, electron beam lithography and plasma etching on amorphous Co{sub 74}Si{sub 26} magnetic films with a well-defined uniaxial anisotropy. The magnetic behavior of two identical antidot arrays but with different hole depth in comparison with film thickness has been studied by transverse magneto-optical Kerr effect. Significant differences appear in the coercivity depending on whether the magnetic film is completely perforated or not, indicating a much more effective domain wall pinning process when the depth of the holes is smaller than the magnetic film thickness.
Lattice gauge theory using parallel processors
International Nuclear Information System (INIS)
Lee, T.D.; Chou, K.C.; Zichichi, A.
1987-01-01
The book's contents include: Lattice Gauge Theory Lectures: Introduction and Current Fermion Simulations; Monte Carlo Algorithms for Lattice Gauge Theory; Specialized Computers for Lattice Gauge Theory; Lattice Gauge Theory at Finite Temperature: A Monte Carlo Study; Computational Method - An Elementary Introduction to the Langevin Equation, Present Status of Numerical Quantum Chromodynamics; Random Lattice Field Theory; The GF11 Processor and Compiler; and The APE Computer and First Physics Results; Columbia Supercomputer Project: Parallel Supercomputer for Lattice QCD; Statistical and Systematic Errors in Numerical Simulations; Monte Carlo Simulation for LGT and Programming Techniques on the Columbia Supercomputer; Food for Thought: Five Lectures on Lattice Gauge Theory
Embedded Lattice and Properties of Gram Matrix
Directory of Open Access Journals (Sweden)
Futa Yuichi
2017-03-01
Full Text Available In this article, we formalize in Mizar [14] the definition of embedding of lattice and its properties. We formally define an inner product on an embedded module. We also formalize properties of Gram matrix. We formally prove that an inverse of Gram matrix for a rational lattice exists. Lattice of Z-module is necessary for lattice problems, LLL (Lenstra, Lenstra and Lov´asz base reduction algorithm [16] and cryptographic systems with lattice [17].
International Nuclear Information System (INIS)
Poschl, M.; Borkovec, V.; Zelenka, J.; Prochazka, J.
1994-01-01
The post-Chernobyl 137 Cs contamination caused gut uptake of this nuclide by ruminants, pigs and laying hens. The application of several clay minerals, stable caesium as well as hexacyanoferrate and related compounds has shown to be effective in reducing the gut uptake. The aim of this study was focused on a possibility of the suppression of gut uptake of 13 '7Cs from the contaminated feed mixture to broiler chicken and/or increasing the rate of excretion of 137 Cs from tissues of broiler chicken by a special food additive (RADECONT, i.e. 98% of clinoptilolite + 2% of FeHCF, made by BIOPOR, CZ). The antidote material RADECONT was added to the feed mixture 2 hours after application of artificially contaminated feed (5kBq of 137 Cs per chicken). The dose of the material was 0.5g per kg body weight and it was repeated daily. The control chickens were given 137 Cs but not antidote in the feed. Lower radiocaesium activities in breast and leg muscles (statistically significant, P 137 Cs administration. The biological half-lives of 137 Cs in the controls treated animals were similar. Application of RADECONT decreased the uptake of radiocaesium in tissues (by up to 20% in muscles) but did not enhance the excretion rate of 137 Cs. (author)
Bogan, Reinhard; Koller, Marianne; Klaubert, Bernd
2012-01-01
As reactivators of inhibited acetylcholinesterase, oximes are essential antidotes in poisoning by organophosphorus compounds. Due to its superior efficacy in cases of soman, cyclosarin, and sarin poisoning, the oxime HI-6 represents a promising option for an active pharmaceutical ingredient (API) in the further development of antidote therapy for nerve agent poisoning. Developmental lots of HI-6 DMS (dimethanesulfonate) provided by different manufacturers were examined with respect to their content and purity with a view to their future use as an API. There are distinct differences in the HI-6 content from three manufacturers. With respect to purity, gradual differences arise with the known synthetic by-products as well as with unknown accompanying compounds. It became apparent that in the case of a modified synthesis using protective groups, the proportion of some synthesis by-products decreases considerably. With one exception, they are thus below the reporting threshold for API in accordance with pertinent regulatory guidelines. In HI-6, an unknown impurity always occurs, whose percentage necessitates identification due to regulations. This unknown impurity, which has not been described so far, could be identified as an isomer. These findings supply data required for the description of pharmaceutical quality in accordance with module 3 of a Common Technical Document (CTD). They thus contribute to the marketing authorization of this substance as an API for auto-injectors and infusions. Copyright © 2012 John Wiley & Sons, Ltd.
Directory of Open Access Journals (Sweden)
Motahareh Soltani
2016-08-01
Full Text Available Objectives: Aluminium phosphide (AlP is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3, a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. Methods: This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Results: Activated charcoal significantly reduced the volume of released gas (P <0.01. Although boric acid did not significantly reduce the volume of released gas, it significantly reduced the rate of gas evolution (P <0.01. A gaseous adduct was formed in the reaction between pure AlP and boric acid. Conclusion: These findings indicate that boric acid may be an efficient and non-toxic antidote for PH3 poisoning.
Role of hydroxocobalamin in acute cyanide poisoning.
Shepherd, Greene; Velez, Larissa I
2008-05-01
To review the recently approved cyanide antidote, hydroxocobalamin, and describe its role in therapy. Relevant publications were identified through a systematic search of PubMed using the MeSH terms and key words hydroxocobalamin and cyanide. This search was then limited to human studies published since 2000. Systematic searches were conducted through January 2008. References from identified articles were reviewed for additional pertinent human studies. The literature search retrieved 7 studies on the safety and/or efficacy of hydroxocobalamin in humans. Four new studies were identified by the search and 3 studies were identified from the references. Studies of antidote efficacy in humans are ethically and logistically difficult. A preclinical study demonstrated that intravenous doses of hydroxocobalamin 5 g are well tolerated by volunteer subjects. Hydroxocobalamin has been shown to reduce cyanide concentrations in controlled studies of nitroprusside therapy and in heavy smokers. A retrospective study of 14 acute cyanide poisonings also demonstrated hydroxocobalamin's safety and efficacy. Two studies examining hydroxocobalamin for smoke inhalation-associated cyanide poisoning indicated a possible benefit, but they are insufficient to establish definitive criteria for use in this setting. Randomized controlled trials of hydroxocobalamin and traditional cyanide antidotes (nitrites/thiosulfate) are lacking. Cyanide poisoning can rapidly cause death. Having an effective antidote readily available is essential for facilities that provide emergency care. In cases of cyanide ingestion, both the nitrite/thiosulfate combination and hydroxocobalamin are effective antidotes. Hydroxocobalamin offers an improved safety profile for children and pregnant women. Hydroxocobalamin also appears to have a better safety profile in the setting of cyanide poisoning in conjunction with smoke inhalation. However, current data are insufficient to recommend the empiric administration of
Intramuscular versus Intraosseous Delivery of Nerve Agent Antidote Pralidoxime Chloride in Swine.
Uwaydah, Nabeel I; Hoskins, Stephen L; Bruttig, Stephen P; Farrar, Henry; Copper, Nick C; Deyo, Donald J; Dubick, Michael A; Kramer, George C
2016-01-01
Exposure to nerve agents requires prompt treatment. We hypothesized that intraosseous (IO) injections of drug antidotes into the vascularized bone marrow will provide a more rapid and effective means to treat exposure to nerve agents than standard intramuscular (IM) injections. We compared the pharmacokinetics of IM and IO administration of pralidoxime chloride (2-PAM Cl) during normovolemia and hypovolemia, as well as their combined administration during normovolemia in swine. Ten normovolemic swine were randomly administered 2 mL, 660 mg 2-PAM Cl via the IM or IO route and monitored for 180 minutes. IM versus IO also was compared in 8 hypovolemic swine bled to a mean arterial pressure of 50 mmHg. In a combined group, an IO injection was administered followed by an IM injection 60 minutes later. Blood samples were collected at times over a 180-minute period to calculate standard pharmacokinetic variables to compare the 2 routes of administration. In the normovolemic swine, IM injection achieved therapeutic levels (4 μg/mL) in 2 minutes, whereas IO infusion achieved these levels in less than 15 seconds. 2-PAM-Cl concentrations fell below these levels at 60 minutes post-injection in both groups. In the hypovolemic swine, IM injection achieved therapeutic levels in 4 minutes compared to less than 15 seconds in the IO group. 2-PAM-Cl concentrations fell below therapeutic levels at 12 and 90 minutes post-injection in the IM and IO groups, respectively. In the combined IO-IM treatment, plasma levels remained above therapeutic levels for the entire experiment and had two concentration peaks that corresponded to IO and IM injections. The IO route for the delivery of 2-PAM Cl provides a significant time and high initial blood concentrations advantage compared to the IM route for the prehospital treatment of nerve agent exposure even under hypovolemic conditions. The initial concentration peak associated with IO, but not IM, may provide greater initial therapy at the
Lattice dislocation in Si nanowires
Energy Technology Data Exchange (ETDEWEB)
Omar, M.S., E-mail: dr_m_s_omar@yahoo.co [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq); Taha, H.T. [Department of Physics, College of Science, University of Salahaddin, Arbil, Iraqi Kurdistan (Iraq)
2009-12-15
Modified formulas were used to calculate lattice thermal expansion, specific heat and Bulk modulus for Si nanowires with diameters of 115, 56, 37 and 22 nm. From these values and Gruneisen parameter taken from reference, mean lattice volumes were found to be as 20.03 A{sup 3} for the bulk and 23.63, 29.91, 34.69 and 40.46 A{sup 3} for Si nanowire diameters mentioned above, respectively. Their mean bonding length was calculated to be as 0.235 nm for the bulk and 0.248, 0.269, 0.282 and 0.297 nm for the nanowires diameter mentioned above, respectively. By dividing the nanowires diameter on the mean bonding length, number of layers per each nanowire size was found to be as 230, 104, 65 and 37 for the diameters mentioned above, respectively. Lattice dislocations in 22 nm diameter wire were found to be from 0.00324 nm for the 1st central lattice to 0.2579 nm for the last surface lattice. Such dislocation was smaller for larger wire diameters. Dislocation concentration found to change in Si nanowires according to the proportionalities of surface thickness to nanowire radius ratios.
Finite-lattice-spacing corrections to masses and g factors on a lattice
International Nuclear Information System (INIS)
Roskies, R.; Wu, J.C.
1986-01-01
We suggest an alternative method for extracting masses and g factors from lattice calculations. Our method takes account of more of the infrared and ultraviolet lattice effects. It leads to more reasonable results in simulations of QED on a lattice
Frustrated lattices of Ising chains
International Nuclear Information System (INIS)
Kudasov, Yurii B; Korshunov, Aleksei S; Pavlov, V N; Maslov, Dmitrii A
2012-01-01
The magnetic structure and magnetization dynamics of systems of plane frustrated Ising chain lattices are reviewed for three groups of compounds: Ca 3 Co 2 O 6 , CsCoCl 3 , and Sr 5 Rh 4 O 12 . The available experimental data are analyzed and compared in detail. It is shown that a high-temperature magnetic phase on a triangle lattice is normally and universally a partially disordered antiferromagnetic (PDA) structure. The diversity of low-temperature phases results from weak interactions that lift the degeneracy of a 2D antiferromagnetic Ising model on the triangle lattice. Mean-field models, Monte Carlo simulation results on the static magnetization curve, and results on slow magnetization dynamics obtained with Glauber's theory are discussed in detail. (reviews of topical problems)
Lattice QCD without topology barriers
Lüscher, Martin
2011-01-01
As the continuum limit is approached, lattice QCD simulations tend to get trapped in the topological charge sectors of field space and may consequently give biased results in practice. We propose to bypass this problem by imposing open (Neumann) boundary conditions on the gauge field in the time direction. The topological charge can then flow in and out of the lattice, while many properties of the theory (the hadron spectrum, for example) are not affected. Extensive simulations of the SU(3) gauge theory, using the HMC and the closely related SMD algorithm, confirm the absence of topology barriers if these boundary conditions are chosen. Moreover, the calculated autocorrelation times are found to scale approximately like the square of the inverse lattice spacing, thus supporting the conjecture that the HMC algorithm is in the universality class of the Langevin equation.
Soliton mobility in disordered lattices.
Sun, Zhi-Yuan; Fishman, Shmuel; Soffer, Avy
2015-10-01
We investigate soliton mobility in the disordered Ablowitz-Ladik (AL) model and the standard nonlinear Schrödinger (NLS) lattice with the help of an effective potential generalizing the Peierls-Nabarro potential. This potential results from a deviation from integrability, which is due to randomness for the AL model, and both randomness and lattice discreteness for the NLS lattice. The statistical properties of such a potential are analyzed, and it is shown how the soliton mobility is affected by its size. The usefulness of this effective potential in studying soliton dynamics is demonstrated numerically. Furthermore, we propose two ways to enhance soliton transport in the presence of disorder: one is to use specific realizations of randomness, and the other is to consider a specific soliton pair.
Lattice QCD for nuclear physics
Meyer, Harvey
2015-01-01
With ever increasing computational resources and improvements in algorithms, new opportunities are emerging for lattice gauge theory to address key questions in strongly interacting systems, such as nuclear matter. Calculations today use dynamical gauge-field ensembles with degenerate light up/down quarks and the strange quark and it is possible now to consider including charm-quark degrees of freedom in the QCD vacuum. Pion masses and other sources of systematic error, such as finite-volume and discretization effects, are beginning to be quantified systematically. Altogether, an era of precision calculation has begun, and many new observables will be calculated at the new computational facilities. The aim of this set of lectures is to provide graduate students with a grounding in the application of lattice gauge theory methods to strongly interacting systems, and in particular to nuclear physics. A wide variety of topics are covered, including continuum field theory, lattice discretizations, hadron spect...
Equations Holding in Hilbert Lattices
Mayet, René
2006-07-01
We produce and study several sequences of equations, in the language of orthomodular lattices, which hold in the ortholattice of closed subspaces of any classical Hilbert space, but not in all orthomodular lattices. Most of these equations hold in any orthomodular lattice admitting a strong set of states whose values are in a real Hilbert space. For some of these equations, we give conditions under which they hold in the ortholattice of closed subspaces of a generalised Hilbert space. These conditions are relative to the dimension of the Hilbert space and to the characteristic of its division ring of scalars. In some cases, we show that these equations cannot be deduced from the already known equations, and we study their mutual independence. To conclude, we suggest a new method for obtaining such equations, using the tensorial product.
Nucleon structure from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Dinter, Simon
2012-11-13
In this thesis we compute within lattice QCD observables related to the structure of the nucleon. One part of this thesis is concerned with moments of parton distribution functions (PDFs). Those moments are essential elements for the understanding of nucleon structure and can be extracted from a global analysis of deep inelastic scattering experiments. On the theoretical side they can be computed non-perturbatively by means of lattice QCD. However, since the time lattice calculations of moments of PDFs are available, there is a tension between these lattice calculations and the results from a global analysis of experimental data. We examine whether systematic effects are responsible for this tension, and study particularly intensively the effects of excited states by a dedicated high precision computation. Moreover, we carry out a first computation with four dynamical flavors. Another aspect of this thesis is a feasibility study of a lattice QCD computation of the scalar quark content of the nucleon, which is an important element in the cross-section of a heavy particle with the nucleon mediated by a scalar particle (e.g. Higgs particle) and can therefore have an impact on Dark Matter searches. Existing lattice QCD calculations of this quantity usually have a large error and thus a low significance for phenomenological applications. We use a variance-reduction technique for quark-disconnected diagrams to obtain a precise result. Furthermore, we introduce a new stochastic method for the calculation of connected 3-point correlation functions, which are needed to compute nucleon structure observables, as an alternative to the usual sequential propagator method. In an explorative study we check whether this new method is competitive to the standard one. We use Wilson twisted mass fermions at maximal twist in all our calculations, such that all observables considered here have only O(a{sup 2}) discretization effects.
International Nuclear Information System (INIS)
Hla Myo Min; Mya Aye
2004-06-01
The structure of a new coumarin type compound isolated from the entitled species was elucidated by the full spectral analysis consisting of FTIR, 1H NMR, DQF COSY, 13C NMR, DEPT, EIMS (HR-EIMS), HMQC and HMBC. The antidote activities of the fresh juice and the ethanolic extract of the plant, and the isolated compound alternamin were also determined
Chiral symmetry on the lattice
Energy Technology Data Exchange (ETDEWEB)
Creutz, M.
1994-11-01
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model.
Kondo length in bosonic lattices
Giuliano, Domenico; Sodano, Pasquale; Trombettoni, Andrea
2017-09-01
Motivated by the fact that the low-energy properties of the Kondo model can be effectively simulated in spin chains, we study the realization of the effect with bond impurities in ultracold bosonic lattices at half filling. After presenting a discussion of the effective theory and of the mapping of the bosonic chain onto a lattice spin Hamiltonian, we provide estimates for the Kondo length as a function of the parameters of the bosonic model. We point out that the Kondo length can be extracted from the integrated real-space correlation functions, which are experimentally accessible quantities in experiments with cold atoms.
Lattice calculations in gauge theory
International Nuclear Information System (INIS)
Rebbi, C.
1985-01-01
The lattice formulation of quantum gauge theories is discussed as a viable technique for quantitative studies of nonperturbative effects in QCD. Evidence is presented to ascertain that whole classes of lattice actions produce a universal continuum limit. Discrepancies between numerical results from Monto Carlo simulations for the pure gauge system and for the system with gauge and quark fields are discussed. Numerical calculations for QCD require very substantial computational resources. The use of powerful vector processors of special purpose machines, in extending the scope and magnitude or the calculations is considered, and one may reasonably expect that in the near future good quantitative predictions will be obtained for QCD
Nuclear Physics from Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
William Detmold, Silas Beane, Konstantinos Orginos, Martin Savage
2011-01-01
We review recent progress toward establishing lattice Quantum Chromodynamics as a predictive calculational framework for nuclear physics. A survey of the current techniques that are used to extract low-energy hadronic scattering amplitudes and interactions is followed by a review of recent two-body and few-body calculations by the NPLQCD collaboration and others. An outline of the nuclear physics that is expected to be accomplished with Lattice QCD in the next decade, along with estimates of the required computational resources, is presented.
[Lattice degeneration of the retina].
Boĭko, E V; Suetov, A A; Mal'tsev, D S
2014-01-01
Lattice degeneration of the retina is a clinically important type of peripheral retinal dystrophies due to its participation in the pathogenesis of rhegmatogenous retinal detachment. In spite of extensive epidemiological, morphological, and clinical data, the question on causes of this particular type of retinal dystrophies currently remains debatable. Existing hypotheses on pathogenesis of retinal structural changes in lattice degeneration explain it to a certain extent. In clinical ophthalmology it is necessary to pay close attention to this kind of degenerations and distinguish between cases requiring preventive treatment and those requiring monitoring.
Three Classes of Orthomodular Lattices
Greechie, Richard J.; Legan, Bruce J.
2006-02-01
Let mathcal{OML} denote the class of all orthomodular lattices and mathcal{C} denote the class of those that are commutator-finite. Also, let mathcal{C}1 denote the class of orthomodular lattices that satisfy the block extension property, mathcal{C}2 those that satisfy the weak block extension property, and mathcal{C}3 those that are locally finite. We show that the following strict containments hold: mathcal{C} subset mathcal{C}1 subset mathcal{C}2 subset mathcal{C}3 subset mathcal{OML}.
Unconventional superconductivity in honeycomb lattice
Directory of Open Access Journals (Sweden)
P Sahebsara
2013-03-01
Full Text Available The possibility of symmetrical s-wave superconductivity in the honeycomb lattice is studied within a strongly correlated regime, using the Hubbard model. The superconducting order parameter is defined by introducing the Green function, which is obtained by calculating the density of the electrons . In this study showed that the superconducting order parameter appears in doping interval between 0 and 0.5, and x=0.25 is the optimum doping for the s-wave superconductivity in honeycomb lattice.
Machines for lattice gauge theory
International Nuclear Information System (INIS)
Mackenzie, P.B.
1989-05-01
The most promising approach to the solution of the theory of strong interactions is large scale numerical simulation using the techniques of lattice gauge theory. At the present time, computing requirements for convincing calculations of the properties of hadrons exceed the capabilities of even the most powerful commercial supercomputers. This has led to the development of massively parallel computers dedicated to lattice gauge theory. This talk will discuss the computing requirements behind these machines, and general features of the components and architectures of the half dozen major projects now in existence. 20 refs., 1 fig
Chiral symmetry on the lattice
International Nuclear Information System (INIS)
Creutz, M.
1994-11-01
The author reviews some of the difficulties associated with chiral symmetry in the context of a lattice regulator. The author discusses the structure of Wilson Fermions when the hopping parameter is in the vicinity of its critical value. Here one flavor contrasts sharply with the case of more, where a residual chiral symmetry survives anomalies. The author briefly discusses the surface mode approach, the use of mirror Fermions to cancel anomalies, and finally speculates on the problems with lattice versions of the standard model
The Fatou property in p-convex Banach lattices
Curbera, Guillermo P.; Ricker, Werner J.
2007-04-01
New features of the Banach function space , that is, the space of all [nu]-scalarly pth power integrable functions (with 1[less-than-or-equals, slant]pFatou property plays an essential role and leads to a new representation theorem for a large class of abstract p-convex Banach lattices.
The Hoyle state in nuclear lattice effective field theory
Indian Academy of Sciences (India)
We review the calculation of the Hoyle state of 12C in nuclear lattice effective field theory (NLEFT) and its ... trum of 12C, which plays an important role in resonantly enhancing the reaction rate for the so-called triple-α ..... The errors are one-standard-deviation estimates which include statistical Monte Carlo errors and ...
Effects of nanoscale size dependent parameters on lattice thermal ...
Indian Academy of Sciences (India)
tice thermal conductivity to that of the reported experimental curve. ... Introduction. Determination of thermal conductivity of semiconductor nanowires plays a crucial role in ..... experimental values. In order to calculate lattice thermal conductivity for Si nanowires, the crystal size dependent parameters should be taken care of.
Cambal, Leah K; Weitz, Andrew C; Li, Hui-Hua; Zhang, Yang; Zheng, Xi; Pearce, Linda L; Peterson, Jim
2013-05-20
Isoamyl nitrite has previously been considered acceptable as an inhaled cyanide antidote; therefore, the antidotal utility of this organic nitrite compared with sodium nitrite was investigated. To facilitate a quantitative comparison, doses of both sodium nitrite and isoamyl nitrite were given intraperitoneally in equimolar amounts to sublethally cyanide-challenged mice. Righting recovery from the knockdown state was clearly compromised in the isoamyl nitrite-treated animals, the effect being attributable to the toxicity of the isoamyl alchol produced during hydrolysis of the isoamyl nitrite to release nitrite anion. Subsequently, inhaled aqueous sodium nitrite aerosol was demonstrated to ameliorate sublethal cyanide toxicity, when provided to mice after the toxic dose, by the more rapid recovery of righting ability compared to that of the control animals given only the toxicant. Aerosolized sodium nitrite has thus been shown by these experiments to have promise as a better alternative to organic nitrites for development as an inhaled cyanide antidote. The inhaled sodium nitrite led to the production of NO in the bloodstream as determined by the appearance of EPR signals attributable to nitrosylhemoglobin and methemoglobin. The aerosol delivery was performed in an unmetered inhalation chamber, and in this study, no attempt was made to optimize the procedure. It is argued that administration of an effective inhaled aqueous sodium nitrite dose in humans is possible, though just beyond the capability of current individual metered-dose inhaler designs, such as those used for asthma. Finally, working at slightly greater than LD50 NaCN doses, it was fortuitously discovered that (i) anesthesia leads to significantly prolonged survival compared to that of unanesthetized animals and that (ii) the antidotal activity of nitrite anion was completely abolished under anesthesia. Plausible explanations for these effects in mice and their practical consequences in relation to
Thermal characterization of nanoscale phononic crystals using supercell lattice dynamics
Directory of Open Access Journals (Sweden)
Bruce L. Davis
2011-12-01
Full Text Available The concept of a phononic crystal can in principle be realized at the nanoscale whenever the conditions for coherent phonon transport exist. Under such conditions, the dispersion characteristics of both the constitutive material lattice (defined by a primitive cell and the phononic crystal lattice (defined by a supercell contribute to the value of the thermal conductivity. It is therefore necessary in this emerging class of phononic materials to treat the lattice dynamics at both periodicity levels. Here we demonstrate the utility of using supercell lattice dynamics to investigate the thermal transport behavior of three-dimensional nanoscale phononic crystals formed from silicon and cubic voids of vacuum. The periodicity of the voids follows a simple cubic arrangement with a lattice constant that is around an order of magnitude larger than that of the bulk crystalline silicon primitive cell. We consider an atomic-scale supercell which incorporates all the details of the silicon atomic locations and the void geometry. For this supercell, we compute the phonon band structure and subsequently predict the thermal conductivity following the Callaway-Holland model. Our findings dictate that for an analysis based on supercell lattice dynamics to be representative of the properties of the underlying lattice model, a minimum supercell size is needed along with a minimum wave vector sampling resolution. Below these minimum values, a thermal conductivity prediction of a bulk material based on a supercell will not adequately recover the value obtained based on a primitive cell. Furthermore, our results show that for the relatively small voids and void spacings we consider (where boundary scattering is dominant, dispersion at the phononic crystal unit cell level plays a noticeable role in determining the thermal conductivity.
Non-perturbative renormalization on the lattice
International Nuclear Information System (INIS)
Koerner, Daniel
2014-01-01
Strongly-interacting theories lie at the heart of elementary particle physics. Their distinct behaviour shapes our world sui generis. We are interested in lattice simulations of supersymmetric models, but every discretization of space-time inevitably breaks supersymmetry and allows renormalization of relevant susy-breaking operators. To understand the role of such operators, we study renormalization group trajectories of the nonlinear O(N) Sigma model (NLSM). Similar to quantum gravity, it is believed to adhere to the asymptotic safety scenario. By combining the demon method with blockspin transformations, we compute the global flow diagram. In two dimensions, we reproduce asymptotic freedom and in three dimensions, asymptotic safety is demonstrated. Essential for these results is the application of a novel optimization scheme to treat truncation errors. We proceed with a lattice simulation of the supersymmetric nonlinear O(3) Sigma model. Using an original discretization that requires to fine tune only a single operator, we argue that the continuum limit successfully leads to the correct continuum physics. Unfortunately, for large lattices, a sign problem challenges the applicability of Monte Carlo methods. Consequently, the last chapter of this thesis is spent on an assessment of the fermion-bag method. We find that sign fluctuations are thereby significantly reduced for the susy NLSM. The proposed discretization finally promises a direct confirmation of supersymmetry restoration in the continuum limit. For a complementary analysis, we study the one-flavor Gross-Neveu model which has a complex phase problem. However, phase fluctuations for Wilson fermions are very small and no conclusion can be drawn regarding the potency of the fermion-bag approach for this model.
Lattice quantum chromodynamics: Some topics
Indian Academy of Sciences (India)
susceptibility and the screening lengths. A short summary is provided at the end. 2. .... approximations but decreasing order of computer time, are (i) full QCD simulations on smaller lattices, (ii) partially quenched ... Theoretical expectations and simulation results for QCD phase diagram. over to different number of flavours.
Lattice dynamics of strontium tungstate
Indian Academy of Sciences (India)
earth atom). Using these models we could calculate [7,10–12] high pressure and temperature phase diagrams as well as thermodynamic properties for ASiO4, RPO4 and RVO4 in the ambient pressure as well as high pressure phases. Now in order to validate the lattice dynamical model developed for SrWO4 we have ...
Flavor extrapolation in lattice QCD
International Nuclear Information System (INIS)
Duffy, W.C.
1984-01-01
Explicit calculation of the effect of virtual quark-antiquark pairs in lattice QCD has eluded researchers. To include their effect explicitly one must calculate the determinant of the fermion-fermion coupling matrix. Owing to the large number of sites in a continuum limit size lattice, direct evaluation of this term requires an unrealistic amount of computer time. The effect of the virtual pairs can be approximated by ignoring this term and adjusting lattice couplings to reproduce experimental results. This procedure is called the valence approximation since it ignores all but the minimal number of quarks needed to describe hadrons. In this work the effect of the quark-antiquark pairs has been incorporated in a theory with an effective negative number of quark flavors contributing to the closed loops. Various particle masses and decay constants have been calculated for this theory and for one with no virtual pairs. The author attempts to extrapolate results towards positive numbers of quark flavors. The results show approximate agreement with experimental measurements and demonstrate the smoothness of lattice expectations in the number of quark flavors
Lattice dynamics of lithium oxide
Indian Academy of Sciences (India)
Li2O finds several important technological applications, as it is used in solid-state batteries, can be used as a blanket breeding material in nuclear fusion reactors, etc. Li2O exhibits a fast ion phase, characterized by a thermally induced dynamic disorder in the anionic sub-lattice of Li+, at elevated temperatures around 1200 ...
Anisotropic dissipation in lattice metamaterials
Directory of Open Access Journals (Sweden)
Dimitri Krattiger
2016-12-01
Full Text Available Plane wave propagation in an elastic lattice material follows regular patterns as dictated by the nature of the lattice symmetry and the mechanical configuration of the unit cell. A unique feature pertains to the loss of elastodynamic isotropy at frequencies where the wavelength is on the order of the lattice spacing or shorter. Anisotropy may also be realized at lower frequencies with the inclusion of local resonators, especially when designed to exhibit directionally non-uniform connectivity and/or cross-sectional geometry. In this paper, we consider free and driven waves within a plate-like lattice−with and without local resonators−and examine the effects of damping on the isofrequency dispersion curves. We also examine, for free waves, the effects of damping on the frequency-dependent anisotropy of dissipation. Furthermore, we investigate the possibility of engineering the dissipation anisotropy by tuning the directional properties of the prescribed damping. The results demonstrate that uniformly applied damping tends to reduce the intensity of anisotropy in the isofrequency dispersion curves. On the other hand, lattice crystals and metamaterials are shown to provide an excellent platform for direction-dependent dissipation engineering which may be realized by simple changes in the spatial distribution of the damping elements.
Computers for lattice field theories
International Nuclear Information System (INIS)
Iwasaki, Y.
1994-01-01
Parallel computers dedicated to lattice field theories are reviewed with emphasis on the three recent projects, the Teraflops project in the US, the CP-PACS project in Japan and the 0.5-Teraflops project in the US. Some new commercial parallel computers are also discussed. Recent development of semiconductor technologies is briefly surveyed in relation to possible approaches toward Teraflops computers. (orig.)
Lattice dynamics of lithium oxide
Indian Academy of Sciences (India)
Solid State Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085, India. E-mail: knp@apsara.barc.ernet.in ... stants and equation of state have also been calculated which are in good agreement with the available ... Li2O crystallizes in the anti-fluorite structure with a face-centered cubic lattice and belongs to ...
Recent results from lattice calculations
Hashimoto, Shoji
2004-01-01
Recent results from lattice QCD calculations relevant to particle physics phenomenology are reviewed. They include the calculations of strong coupling constant, quark masses, kaon matrix elements, and D and B meson matrix elements. Special emphasis is on the recent progress in the simulations including dynamical quarks.
Lattice Calculations and Hadron Physics
Aoki, Sinya
1999-01-01
We review progress in lattice QCD, focusing on efforts to calculate weak matrix elements relevant for the determination of the Cabibbo-Kobayashi-Maskawa matrix. Topics we discuss include light hadron spectrum and quark masses, CP-violation in K meson decays and weak matrix elements of heavy-light mesons.
Synthesis of spatially variant lattices.
Rumpf, Raymond C; Pazos, Javier
2012-07-02
It is often desired to functionally grade and/or spatially vary a periodic structure like a photonic crystal or metamaterial, yet no general method for doing this has been offered in the literature. A straightforward procedure is described here that allows many properties of the lattice to be spatially varied at the same time while producing a final lattice that is still smooth and continuous. Properties include unit cell orientation, lattice spacing, fill fraction, and more. This adds many degrees of freedom to a design such as spatially varying the orientation to exploit directional phenomena. The method is not a coordinate transformation technique so it can more easily produce complicated and arbitrary spatial variance. To demonstrate, the algorithm is used to synthesize a spatially variant self-collimating photonic crystal to flow a Gaussian beam around a 90° bend. The performance of the structure was confirmed through simulation and it showed virtually no scattering around the bend that would have arisen if the lattice had defects or discontinuities.
Lattice quantum chromodynamics: Some topics
Indian Academy of Sciences (India)
For reasons of both time and interest, I have chosen to limit this review to some se- lected topics. I will begin with a lightning quick overview of the basic lattice gauge theory and then go on to discuss the recent results on the QCD phase diagram, quark number susceptibility and the screening lengths. A short summary is ...
Lattice dynamics of lithium oxide
Indian Academy of Sciences (India)
Abstract. Li2O finds several important technological applications, as it is used in solid- state batteries, can be used as a blanket breeding material in nuclear fusion reactors, etc. Li2O exhibits a fast ion phase, characterized by a thermally induced dynamic disorder in the anionic sub-lattice of Li+, at elevated temperatures ...
Disconnected Diagrams in Lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Gambhir, Arjun [College of William and Mary, Williamsburg, VA (United States)
2017-08-01
In this work, we present state-of-the-art numerical methods and their applications for computing a particular class of observables using lattice quantum chromodynamics (Lattice QCD), a discretized version of the fundamental theory of quarks and gluons. These observables require calculating so called \\disconnected diagrams" and are important for understanding many aspects of hadron structure, such as the strange content of the proton. We begin by introducing the reader to the key concepts of Lattice QCD and rigorously define the meaning of disconnected diagrams through an example of the Wick contractions of the nucleon. Subsequently, the calculation of observables requiring disconnected diagrams is posed as the computationally challenging problem of finding the trace of the inverse of an incredibly large, sparse matrix. This is followed by a brief primer of numerical sparse matrix techniques that overviews broadly used methods in Lattice QCD and builds the background for the novel algorithm presented in this work. We then introduce singular value deflation as a method to improve convergence of trace estimation and analyze its effects on matrices from a variety of fields, including chemical transport modeling, magnetohydrodynamics, and QCD. Finally, we apply this method to compute observables such as the strange axial charge of the proton and strange sigma terms in light nuclei. The work in this thesis is innovative for four reasons. First, we analyze the effects of deflation with a model that makes qualitative predictions about its effectiveness, taking only the singular value spectrum as input, and compare deflated variance with different types of trace estimator noise. Second, the synergy between probing methods and deflation is investigated both experimentally and theoretically. Third, we use the synergistic combination of deflation and a graph coloring algorithm known as hierarchical probing to conduct a lattice calculation of light disconnected matrix elements
Inelastic neutron scattering and lattice dynamics studies in complex solids
International Nuclear Information System (INIS)
Rao, Mala N.; Mittal, R.; Choudhury, Narayani; Chaplot, S.L.
2004-01-01
At Trombay, lattice dynamics studies employing coherent inelastic neutron scattering (INS) experiments have been carried out at the two research reactors, CIRUS and Dhruva. While the early work at CIRUS involved many elemental solids and ionic molecular solids, recent experiments at Dhruva have focussed on certain superconductors (cuprates and intermetallics), geophysically important minerals (Al 2 SiO 5 , ZrSiO 4 , MnCO 3 ) and layered halides (BaFCl, ZnCl 2 ). In most of the studies, theoretical modelling of lattice dynamics has played a significant role in the interpretation and analysis of the results from experiments. This talk summarises the developments and current activities in the field of inelastic neutron scattering and lattice dynamics at Trombay. (author)
Degenerate Fermi gas in a combined harmonic-lattice potential
International Nuclear Information System (INIS)
Blakie, P. B.; Bezett, A.; Buonsante, P.
2007-01-01
In this paper we derive an analytic approximation to the density of states for atoms in a combined optical lattice and harmonic trap potential as used in current experiments with quantum degenerate gases. We compare this analytic density of states to numerical solutions and demonstrate its validity regime. Our work explicitly considers the role of higher bands and when they are important in quantitative analysis of this system. Applying our density of states to a degenerate Fermi gas, we consider how adiabatic loading from a harmonic trap into the combined harmonic-lattice potential affects the degeneracy temperature. Our results suggest that occupation of excited bands during loading should lead to more favorable conditions for realizing degenerate Fermi gases in optical lattices
RHICAGR a Most Simplified RHIC Lattice
Energy Technology Data Exchange (ETDEWEB)
Ruggiero, A. G. [Brookhaven National Lab. (BNL), Upton, NY (United States)
1991-08-01
In this report I describe an alternative approach to the design of the RHIC lattice. It is not my intention to propose an alternative lattice altogether, but I like to stress the differences in design methodology and philosophy.
Mechanical Behavior of CFRP Lattice Core Sandwich Bolted Corner Joints
Zhu, Xiaolei; Liu, Yang; Wang, Yana; Lu, Xiaofeng; Zhu, Lingxue
2017-12-01
The lattice core sandwich structures have drawn more attention for the integration of load capacity and multifunctional applications. However, the connection of carbon fibers reinforced polymer composite (CFRP) lattice core sandwich structure hinders its application. In this paper, a typical connection of two lattice core sandwich panels, named as corner joint or L-joint, was investigated by experiment and finite element method (FEM). The mechanical behavior and failure mode of the corner joints were discussed. The results showed that the main deformation pattern and failure mode of the lattice core sandwich bolted corner joints structure were the deformation of metal connector and indentation of the face sheet in the bolt holes. The metal connectors played an important role in bolted corner joints structure. In order to save the calculation resource, a continuum model of pyramid lattice core was used to replace the exact structure. The computation results were consistent with experiment, and the maximum error was 19%. The FEM demonstrated the deflection process of the bolted corner joints structure visually. So the simplified FEM can be used for further analysis of the bolted corner joints structure in engineering.
When the GERM Hosts the Antidote: The Surprising New Birth of Israel's Anti-GERM Pre-K Policy
Directory of Open Access Journals (Sweden)
Gadi Bialik
2017-09-01
Full Text Available Since the 1970s, Israel's educational policy has been undergoing a change generated by the neo-liberal agenda. In this light, it is not surprising that since the 1990s, Israel’s education system has adopted the main characteristics of the Global Education Reform Movement (GERM. In light of this, the current research will focus on a newly born pre-K policy formation process that set out as GERM-like in nature, but nevertheless ended up with anti-GERM characteristics. Using historical-narrative qualitative tools, this paper will portray and analyze the main factors that generated the new anti-GERMian reform. We will outline conclusions from the Israeli case study to create a potential conceptual framework that highlights a more complex, hybrid, or dual outlook at the GERM containing its antidote within itself.
Lattice investigations of the QCD phase diagram
Energy Technology Data Exchange (ETDEWEB)
Guenther, Jana
2016-12-15
To understand the physics in the early universe as well as in heavy ion collisions a throughout understanding of the theory of strong interaction, quantum chromodynamics (QCD), is important. Lattice QCD provides a tool to study it from first principles. However due to the sign problem direct simulations with physical conditions are at the moment limited to zero chemical potential. In this thesis I present a circumvention of this problem. We can gain information on the QCD phase diagram and the equation of state from analytical continuation of results extracted from simulations at imaginary chemical potential. The topological susceptibility is very expensive to compute in Lattice QCD. However it provides an important ingredient for the estimation of the axion mass. The axion is a possible candidate for a dark matter, which plays in important role in the understanding of our universe. In this thesis I discuss two techniques that make it possible to determine the topological susceptibility and allow for an estimation of the axion mass. I then use this mass restrain to analyze the idea of an experiment to detect axions with a dielectric mirror.
Lattice investigations of the QCD phase diagram
International Nuclear Information System (INIS)
Guenther, Jana
2016-01-01
To understand the physics in the early universe as well as in heavy ion collisions a throughout understanding of the theory of strong interaction, quantum chromodynamics (QCD), is important. Lattice QCD provides a tool to study it from first principles. However due to the sign problem direct simulations with physical conditions are at the moment limited to zero chemical potential. In this thesis I present a circumvention of this problem. We can gain information on the QCD phase diagram and the equation of state from analytical continuation of results extracted from simulations at imaginary chemical potential. The topological susceptibility is very expensive to compute in Lattice QCD. However it provides an important ingredient for the estimation of the axion mass. The axion is a possible candidate for a dark matter, which plays in important role in the understanding of our universe. In this thesis I discuss two techniques that make it possible to determine the topological susceptibility and allow for an estimation of the axion mass. I then use this mass restrain to analyze the idea of an experiment to detect axions with a dielectric mirror.
Lattice QCD. A critical status report
Energy Technology Data Exchange (ETDEWEB)
Jansen, Karl
2008-10-15
The substantial progress that has been achieved in lattice QCD in the last years is pointed out. I compare the simulation cost and systematic effects of several lattice QCD formulations and discuss a number of topics such as lattice spacing scaling, applications of chiral perturbation theory, non-perturbative renormalization and finite volume effects. Additionally, the importance of demonstrating universality is emphasized. (orig.)
Spatiotemporal complexity in coupled map lattices
International Nuclear Information System (INIS)
Kaneko, Kunihiko
1986-01-01
Some spatiotemporal patterns of couple map lattices are presented. The chaotic kink-like motions are shown for the phase motion of the coupled circle lattices. An extension of the couple map lattice approach to Hamiltonian dynamics is briefly reported. An attempt to characterize the high-dimensional attractor by the extension of the correlation dimension is discussed. (author)
Possible lattice organs in Cretaceous Thylacocephala
Lange, Sven; Schram, Frederick R.
2002-01-01
Structures, reminiscent of the lattice organs in thecostracan crustaceans, are described from the carapace cuticle of Cretaceous thylacocephalans. The new lattice organ like structures occur in pairs along the dorsal midline. While these have a similar outline to true lattice organs, they seem to
Lattice gaugefixing and other optics in lattice gauge theory
Energy Technology Data Exchange (ETDEWEB)
Yee, Ken [Brookhaven National Lab. (BNL), Upton, NY (United States)
1992-06-01
We present results from four projects. In the first, quark and gluon propagators and effective masses and ΔI = 1/2 Rule operator matching coefficients are computed numerically in gaugefixed lattice QCD. In the second, the same quantities are evaluated analytically in the strong coupling, N → ∞limit. In the third project, the Schwinger model is studied in covariant gauges, where we show that the effective electron mass varies with the gauge parameter and that longitudinal gaugefixing ambiguities affect operator product expansion coefficients (analogous to ΔI = 1/2 Rule matching coefficients) determined by matching gauge variant matrix elements. However, we find that matching coefficients even if shifted by the unphysical modes are χ invariant. In the fourth project, we show that the strong coupling parallelogram lattice Schwinger model as a different thermodynamic limit than the weak coupling continuum limit. As a function of lattice skewness angle these models span the Δ = -1 critical line of 6-vertex models which, in turn, have been identified as c = 1 conformal field theories.
Lattice gaugefixing and other optics in lattice gauge theory
Energy Technology Data Exchange (ETDEWEB)
Yee, Ken.
1992-06-01
We present results from four projects. In the first, quark and gluon propagators and effective masses and {Delta}I = 1/2 Rule operator matching coefficients are computed numerically in gaugefixed lattice QCD. In the second, the same quantities are evaluated analytically in the strong coupling, N {yields} {infinity} limit. In the third project, the Schwinger model is studied in covariant gauges, where we show that the effective electron mass varies with the gauge parameter and that longitudinal gaugefixing ambiguities affect operator product expansion coefficients (analogous to {Delta}I = 1/2 Rule matching coefficients) determined by matching gauge variant matrix elements. However, we find that matching coefficients even if shifted by the unphysical modes are {xi} invariant. In the fourth project, we show that the strong coupling parallelogram lattice Schwinger model as a different thermodynamic limit than the weak coupling continuum limit. As a function of lattice skewness angle these models span the {Delta} = {minus}1 critical line of 6-vertex models which, in turn, have been identified as c = 1 conformal field theories.
Inexpensive chirality on the lattice
International Nuclear Information System (INIS)
Kamleh, W.; Williams, A.G.; Adams, D.
2000-01-01
Full text: Implementing lattice fermions that resemble as closely as possible continuum fermions is one of the main goals of the theoretical physics community. Aside from a lack of infinitely powerful computers, one of the main impediments to this is the Nielsen-Ninomiya No-Go theorem for chirality on the lattice. One of the consequences of this theorem is that exact chiral symmetry and a lack of fermion doublers cannot be simultaneously satisfied for fermions on the lattice. In the commonly used Wilson fermion formulation, chiral symmetry is explicitly sacrificed on the lattice to avoid fermion doubling. Recently, an alternative has come forward, namely, the Ginsparg-Wilson relation and one of its solutions, the Overlap fermion. The Ginsparg-Wilson relation is a statement of lattice-deformed chirality. The Overlap-Dirac operator is a member of the family of solutions of the Ginsparg-Wilson relation. In recent times, Overlap fermions have been of great interest to the community due to their excellent chiral properties. However, they are significantly more expensive to implement than Wilson fermions. This expense is primarily due to the fact that the Overlap implementation requires an evaluation of the sign function for the Wilson-Dirac operator. The sign function is approximated by a high order rational polynomial function, but this approximation is poor close to the origin. The less near-zero modes that the Wilson- Dirac operator possesses, the cheaper the Overlap operator will be to implement. A means of improving the eigenvalue properties of the Wilson-Dirac operator by the addition of a so-called 'Clover' term is put forward. Numerical results are given that demonstrate this improvement. The Nielsen-Ninomiya no-go theorem and chirality on the lattice are reviewed. The general form of solutions of the Ginsparg-Wilson relation are given, and the Overlap solution is discussed. Properties of the Overlap-Dirac operator are given, including locality and analytic
Aliasing modes in the lattice Schwinger model
International Nuclear Information System (INIS)
Campos, Rafael G.; Tututi, Eduardo S.
2007-01-01
We study the Schwinger model on a lattice consisting of zeros of the Hermite polynomials that incorporates a lattice derivative and a discrete Fourier transform with many properties. Such a lattice produces a Klein-Gordon equation for the boson field and the exact value of the mass in the asymptotic limit if the boundaries are not taken into account. On the contrary, if the lattice is considered with boundaries new modes appear due to aliasing effects. In the continuum limit, however, this lattice yields also a Klein-Gordon equation with a reduced mass
Computing nucleon EDM on a lattice
Abramczyk, Michael; Aoki, Sinya; Blum, Tom; Izubuchi, Taku; Ohki, Hiroshi; Syritsyn, Sergey
2018-03-01
I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results and the phenomenological estimates of the nucleon EDM. On the other hand, the nucleon EDM becomes much harder to compute on a lattice. In addition, I will review the progress in computing quark chromo-EDM-induced nucleon EDM using chiral quark action.
Heavy water critical experiments on plutonium lattice
International Nuclear Information System (INIS)
Miyawaki, Yoshio; Shiba, Kiminori
1975-06-01
This report is the summary of physics study on plutonium lattice made in Heavy Water Critical Experiment Section of PNC. By using Deuterium Critical Assembly, physics study on plutonium lattice has been carried out since 1972. Experiments on following items were performed in a core having 22.5 cm square lattice pitch. (1) Material buckling (2) Lattice parameters (3) Local power distribution factor (4) Gross flux distribution in two region core (5) Control rod worth. Experimental results were compared with theoretical ones calculated by METHUSELAH II code. It is concluded from this study that calculation by METHUSELAH II code has acceptable accuracy in the prediction on plutonium lattice. (author)
Computing nucleon EDM on a lattice
Energy Technology Data Exchange (ETDEWEB)
Abramczyk, Michael; Izubuchi, Taku
2017-06-18
I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results and the phenomenological estimates of the nucleon EDM. On the other hand, the nucleon EDM becomes much harder to compute on a lattice. In addition, I will review the progress in computing quark chromo-EDM-induced nucleon EDM using chiral quark action.
Active particles in periodic lattices
Chamolly, Alexander; Ishikawa, Takuji; Lauga, Eric
2017-11-01
Both natural and artificial small-scale swimmers may often self-propel in environments subject to complex geometrical constraints. While most past theoretical work on low-Reynolds number locomotion addressed idealised geometrical situations, not much is known on the motion of swimmers in heterogeneous environments. As a first theoretical model, we investigate numerically the behaviour of a single spherical micro-swimmer located in an infinite, periodic body-centred cubic lattice consisting of rigid inert spheres of the same size as the swimmer. Running a large number of simulations we uncover the phase diagram of possible trajectories as a function of the strength of the swimming actuation and the packing density of the lattice. We then use hydrodynamic theory to rationalise our computational results and show in particular how the far-field nature of the swimmer (pusher versus puller) governs even the behaviour at high volume fractions.
The lattice QCD grand challenge
International Nuclear Information System (INIS)
Kilcup, G.
1991-01-01
Until relatively recently, a taxonomist of science would divide most areas of physics into two types: theoretical and experimental. With the advent of large scale computing, however, there is now another recognized field: computational physics. For there is now another recognized field: computational physics. For High Energy Physics one of the most prominent manifestations of this phenomenon is the emergence of the discipline known as lattice Quantum Chromodynamics, or lattice QCD. Problems which a decade ago seemed intractable are not succumbing to large scale numerical simulations. These simulations are consuming vast amounts of computer time these days, and promise to do so for at least the next decade. To take but one example, in each of the last three years, the Department of Energy has allocated several thousand Cray-2 hours at NERSC for the computation of certain weak interaction matrix elements. In the following pages the author will give a brief overview of this and some other projects
Innovations in Lattice QCD Algorithms
Energy Technology Data Exchange (ETDEWEB)
Konstantinos Orginos
2006-06-25
Lattice QCD calculations demand a substantial amount of computing power in order to achieve the high precision results needed to better understand the nature of strong interactions, assist experiment to discover new physics, and predict the behavior of a diverse set of physical systems ranging from the proton itself to astrophysical objects such as neutron stars. However, computer power alone is clearly not enough to tackle the calculations we need to be doing today. A steady stream of recent algorithmic developments has made an important impact on the kinds of calculations we can currently perform. In this talk I am reviewing these algorithms and their impact on the nature of lattice QCD calculations performed today.
Shear Viscosity from Lattice QCD
Mages, Simon W; Fodor, Zoltán; Schäfer, Andreas; Szabó, Kálmán
2015-01-01
Understanding of the transport properties of the the quark-gluon plasma is becoming increasingly important to describe current measurements at heavy ion collisions. This work reports on recent efforts to determine the shear viscosity h in the deconfined phase from lattice QCD. The main focus is on the integration of the Wilson flow in the analysis to get a better handle on the infrared behaviour of the spectral function which is relevant for transport. It is carried out at finite Wilson flow time, which eliminates the dependence on the lattice spacing. Eventually, a new continuum limit has to be carried out which sends the new regulator introduced by finite flow time to zero. Also the non-perturbative renormalization strategy applied for the energy momentum tensor is discussed. At the end some quenched results for temperatures up to 4 : 5 T c are presented
Symplectic maps for accelerator lattices
International Nuclear Information System (INIS)
Warnock, R.L.; Ruth, R.; Gabella, W.
1988-05-01
We describe a method for numerical construction of a symplectic map for particle propagation in a general accelerator lattice. The generating function of the map is obtained by integrating the Hamilton-Jacobi equation as an initial-value problem on a finite time interval. Given the generating function, the map is put in explicit form by means of a Fourier inversion technique. We give an example which suggests that the method has promise. 9 refs., 9 figs
Harmonic Lattice Dynamics of Germanium
International Nuclear Information System (INIS)
Nelin, G.
1974-01-01
The phonon dispersion relations of the Δ-, Λ-, and Σ-directions of germanium at 80 K are analysed in terms of current harmonic lattice dynamical models. On the basis of this experience, a new model is proposed which gives a unified account of the strong points of the previous models. The principal elements of the presented theory are quasiparticle bond charges combined with a valence force field
Harmonic Lattice Dynamics of Germanium
Energy Technology Data Exchange (ETDEWEB)
Nelin, G.
1974-07-01
The phonon dispersion relations of the DELTA-, LAMBDA-, and SIGMA-directions of germanium at 80 K are analysed in terms of current harmonic lattice dynamical models. On the basis of this experience, a new model is proposed which gives a unified account of the strong points of the previous models. The principal elements of the presented theory are quasiparticle bond charges combined with a valence force field.
Apiary B Factory lattice design
International Nuclear Information System (INIS)
Donald, M.H.R.; Garren, A.A.
1991-04-01
The Apiary B Factory is a proposed high-intensity electron-positron collider. This paper will present the lattice design for this facility, which envisions two rings with unequal energies in the PEP tunnel. The design has many interesting optical and geometrical features due to the needs to conform to the existing tunnel, and to achieve the necessary emittances, damping times and vacuum. Existing hardware is used to a maximum extent. 8 figs. 1 tab
Energy Technology Data Exchange (ETDEWEB)
Sommer, Rainer [DESY, Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2014-02-15
The principles of scale setting in lattice QCD as well as the advantages and disadvantages of various commonly used scales are discussed. After listing criteria for good scales, I concentrate on the main presently used ones with an emphasis on scales derived from the Yang-Mills gradient flow. For these I discuss discretisation errors, statistical precision and mass effects. A short review on numerical results also brings me to an unpleasant disagreement which remains to be explained.
Lattice engineering technology and applications
Wang, Shumin
2012-01-01
This book contains comprehensive reviews of different technologies to harness lattice mismatch in semiconductor heterostructures and their applications in electronic and optoelectronic devices. While the book is a bit focused on metamorphic epitaxial growth, it also includes other methods like compliant substrate, selective area growth, wafer bonding and heterostructure nanowires etc. Basic knowledge on dislocations in semiconductors and innovative methods to eliminate threading dislocations are provided, and successful device applications are reviewed. It covers a variety of important semicon
Spin lattices of walking droplets
Saenz, Pedro; Pucci, Giuseppe; Goujon, Alexis; Dunkel, Jorn; Bush, John
2017-11-01
We present the results of an experimental investigation of the spontaneous emergence of collective behavior in spin lattice of droplets walking on a vibrating fluid bath. The bottom topography consists of relatively deep circular wells that encourage the walking droplets to follow circular trajectories centered at the lattice sites, in one direction or the other. Wave-mediated interactions between neighboring drops are enabled through a thin fluid layer between the wells. The sense of rotation of the walking droplets may thus become globally coupled. When the coupling is sufficiently strong, interactions with neighboring droplets may result in switches in spin that lead to preferred global arrangements, including correlated (all drops rotating in the same direction) or anti-correlated (neighboring drops rotating in opposite directions) states. Analogies with ferromagnetism and anti-ferromagnetism are drawn. Different spatial arrangements are presented in 1D and 2D lattices to illustrate the effects of topological frustration. This work was supported by the US National Science Foundation through Grants CMMI-1333242 and DMS-1614043.
Effect of lattice strain on the electro-catalytic activity of IrO2for water splitting.
Sun, Wei; Wang, Zhiqiang; Zaman, Waqas Qamar; Zhou, Zhenhua; Cao, Limei; Gong, Xue-Qing; Yang, Ji
2018-01-23
The lattice strain of IrO 2 plays a critical role in determining its OER activity. The Ir-O bond length change in IrO 6 coordination induces lattice strain. Increasing the annealing temperature results in a stretching strain along the c axis and a compressive strain on the a and b axes, leading to a larger c/a ratio. Enhancing the lattice strain decreases the c/a ratio, which is beneficial for improving OER activity.
On the Characterization and Software Implementation of General Protein Lattice Models
Bechini, Alessio
2013-01-01
Abstract models of proteins have been widely used as a practical means to computationally investigate general properties of the system. In lattice models any sterically feasible conformation is represented as a self-avoiding walk on a lattice, and residue types are limited in number. So far, only two- or three-dimensional lattices have been used. The inspection of the neighborhood of alpha carbons in the core of real proteins reveals that also lattices with higher coordination numbers, possibly in higher dimensional spaces, can be adopted. In this paper, a new general parametric lattice model for simplified protein conformations is proposed and investigated. It is shown how the supporting software can be consistently designed to let algorithms that operate on protein structures be implemented in a lattice-agnostic way. The necessary theoretical foundations are developed and organically presented, pinpointing the role of the concept of main directions in lattice-agnostic model handling. Subsequently, the model features across dimensions and lattice types are explored in tests performed on benchmark protein sequences, using a Python implementation. Simulations give insights on the use of square and triangular lattices in a range of dimensions. The trend of potential minimum for sequences of different lengths, varying the lattice dimension, is uncovered. Moreover, an extensive quantitative characterization of the usage of the so-called “move types” is reported for the first time. The proposed general framework for the development of lattice models is simple yet complete, and an object-oriented architecture can be proficiently employed for the supporting software, by designing ad-hoc classes. The proposed framework represents a new general viewpoint that potentially subsumes a number of solutions previously studied. The adoption of the described model pushes to look at protein structure issues from a more general and essential perspective, making computational
Topological magnon bands in ferromagnetic star lattice
Owerre, S. A.
2017-05-01
The experimental observation of topological magnon bands and thermal Hall effect in a kagomé lattice ferromagnet Cu(1-3, bdc) has inspired the search for topological magnon effects in various insulating ferromagnets that lack an inversion center allowing a Dzyaloshinskii-Moriya (DM) spin-orbit interaction. The star lattice (also known as the decorated honeycomb lattice) ferromagnet is an ideal candidate for this purpose because it is a variant of the kagomé lattice with additional links that connect the up-pointing and down-pointing triangles. This gives rise to twice the unit cell of the kagomé lattice, and hence more interesting topological magnon effects. In particular, the triangular bridges on the star lattice can be coupled either ferromagnetically or antiferromagnetically which is not possible on the kagomé lattice ferromagnets. Here, we study DM-induced topological magnon bands, chiral edge modes, and thermal magnon Hall effect on the star lattice ferromagnet in different parameter regimes. The star lattice can also be visualized as the parent material from which topological magnon bands can be realized for the kagomé and honeycomb lattices in some limiting cases.
2013-02-12
and severe toxicity. Cobinamide was 5 times as potent as hydroxocobalamin. hydroxocobalamin, cobinamide, cyanide , poisoning , Vitamin B12a, Vit B12...treatment of acute, severe cyanide induced cardiotoxicity of severe hypotension and of cardiac arrest in a swine (Sus Scrofa) model Intravenous...cobinamide, a novel cyanide antidote, versus hydroxocobalamin in the treatment of acute cyanide toxicity and apnea in a swine (Sus Scrofa) model
Fractional random walk lattice dynamics
Michelitsch, T. M.; Collet, B. A.; Riascos, A. P.; Nowakowski, A. F.; Nicolleau, F. C. G. A.
2017-02-01
We analyze time-discrete and time-continuous ‘fractional’ random walks on undirected regular networks with special focus on cubic periodic lattices in n = 1, 2, 3,.. dimensions. The fractional random walk dynamics is governed by a master equation involving fractional powers of Laplacian matrices {{L}\\fracα{2}}} where α =2 recovers the normal walk. First we demonstrate that the interval 0expressions for the transition matrix of the fractional random walk and closely related the average return probabilities. We further obtain the fundamental matrix {{Z}(α )} , and the mean relaxation time (Kemeny constant) for the fractional random walk. The representation for the fundamental matrix {{Z}(α )} relates fractional random walks with normal random walks. We show that the matrix elements of the transition matrix of the fractional random walk exihibit for large cubic n-dimensional lattices a power law decay of an n-dimensional infinite space Riesz fractional derivative type indicating emergence of Lévy flights. As a further footprint of Lévy flights in the n-dimensional space, the transition matrix and return probabilities of the fractional random walk are dominated for large times t by slowly relaxing long-wave modes leading to a characteristic {{t}-\\frac{n{α}} -decay. It can be concluded that, due to long range moves of fractional random walk, a small world property is emerging increasing the efficiency to explore the lattice when instead of a normal random walk a fractional random walk is chosen.
Beautiful baryons from lattice QCD
Alexandrou, C; Güsken, S; Jegerlehner, F; Schilling, K; Siegert, G; Sommer, Rainer
1994-01-01
We perform a lattice study of heavy baryons, containing one (\\Lambda_b) or two b-quarks (\\Xi_b). Using the quenched approximation we obtain for the mass of \\Lambda_b M_{\\Lambda_b}= 5.728 \\pm 0.144 \\pm 0.018 {\\rm GeV}. The mass splitting between the \\Lambda_b and the B-meson is found to increase by about 20\\% if the light quark mass is varied from the chiral limit to the strange quark mass. ------- Figures obtained upon request from borrelli@psiclu.cern.ch.
Rojas Bocanegra, Alberto
2004-01-01
Objetivo: Determinar la prevalencia de degeneración periférica de retina Lattice y su relación con estados refractivos y rupturas retinales. Metodología: Estudio de corte transversal con exploración de asociación, mediante análisis de casos y controles. Se examinaron 680 ojos en el Instituto de Investigaciones Optométricas e Instituto de Córnea. El estado refractivo se determinó mediante técnica estática y el estado retinal mediante oftalmoscopia indirecta con indentación escleral. Resultados...
Lattice degeneration of the retina.
Byer, N E
1979-01-01
Lattice degeneration of the retina is the most important of all clinically distinct entities that effect the peripheral fundus and are related to retinal detachment. The purpose of this review is to survey the extensive literature, to evaluate the many diverse opinions on this subject, and to correlate and summarize all the known facts regarding this disease entity. The disease is fully defined and described, both clinically and histologically. Some aspects of the disease are still poorly understood, and some remain controversial, especially in the area of management. For this reason, the indications for treatment are discussed under eight subsections, with a view toward providing practical guidelines for recommendations in management.
The lattice dynamics of imidazole
International Nuclear Information System (INIS)
Link, K.H.
1983-05-01
The lattice dynamics of imidazole have been investigated. To this end dispersion curves have been determined at 10 K by inelastic coherent neutron scattering. RAMAN measurements have been done to investigate identical gamma - point modes. The combination of extinction rules for RAMAN - and neutron scattering leads to the symmetry assignment of identical gamma - point modes. The experiment yields a force constant of the streching vibration of the hydrogen bond of 0.33 mdyn/A. A force model has been developed to describe the intermolecular atom - atom Interactions in imidazole. (orig./BHO)
Working Group Report: Lattice Field Theory
Energy Technology Data Exchange (ETDEWEB)
Blum, T.; et al.,
2013-10-22
This is the report of the Computing Frontier working group on Lattice Field Theory prepared for the proceedings of the 2013 Community Summer Study ("Snowmass"). We present the future computing needs and plans of the U.S. lattice gauge theory community and argue that continued support of the U.S. (and worldwide) lattice-QCD effort is essential to fully capitalize on the enormous investment in the high-energy physics experimental program. We first summarize the dramatic progress of numerical lattice-QCD simulations in the past decade, with some emphasis on calculations carried out under the auspices of the U.S. Lattice-QCD Collaboration, and describe a broad program of lattice-QCD calculations that will be relevant for future experiments at the intensity and energy frontiers. We then present details of the computational hardware and software resources needed to undertake these calculations.
Fractional vortex lattice structures in spin-triplet superconductors
International Nuclear Information System (INIS)
Chung, Suk Bum; Agterberg, Daniel F; Kim, Eun-A
2009-01-01
Motivated by recent interest in spin-triplet superconductors, we investigate the vortex lattice structures for this class of unconventional superconductors. We discuss how the order parameter symmetry can give rise to U(1)xU(1) symmetry in the same sense as in spinor condensates, making half-quantum vortices (HQVs) topologically stable. We then calculate the vortex lattice structure of HQVs, with particular attention on the roles of the crystalline lattice, the Zeeman coupling and Meissner screening, all absent in spinor condensates. Finally, we consider how spin-orbit coupling leads to a breakdown of the U(1)xU(1) symmetry in free energy and whether the HQV lattice survives this symmetry breaking. As examples, we examine simpler spin-triplet models proposed in the context of Na x CoO 2 ·yH 2 O and Bechgaard salts, as well as the better known and more complex model for Sr 2 RuO 4 .
Entropic multirelaxation lattice Boltzmann models for turbulent flows.
Bösch, Fabian; Chikatamarla, Shyam S; Karlin, Ilya V
2015-10-01
We present three-dimensional realizations of a class of lattice Boltzmann models introduced recently by the authors [I. V. Karlin, F. Bösch, and S. S. Chikatamarla, Phys. Rev. E 90, 031302(R) (2014)] and review the role of the entropic stabilizer. Both coarse- and fine-grid simulations are addressed for the Kida vortex flow benchmark. We show that the outstanding numerical stability and performance is independent of a particular choice of the moment representation for high-Reynolds-number flows. We report accurate results for low-order moments for homogeneous isotropic decaying turbulence and second-order grid convergence for most assessed statistical quantities. It is demonstrated that all the three-dimensional lattice Boltzmann realizations considered herein converge to the familiar lattice Bhatnagar-Gross-Krook model when the resolution is increased. Moreover, thanks to the dynamic nature of the entropic stabilizer, the present model features less compressibility effects and maintains correct energy and enstrophy dissipation. The explicit and efficient nature of the present lattice Boltzmann method renders it a promising candidate for both engineering and scientific purposes for highly turbulent flows.
Lattice Codes for Physical Layer Communications
Barreal, Amaro
2017-01-01
Lattices are deceptively simple mathematical structures that have become indispensable for code design for physical layer communications. While lattice-related problems are interesting in their own right, the usefulness of these discrete structures in wireless communications provides additional motivation for their study and enables a multidisciplinary line of research. This thesis is devoted to the study of lattice code design for physical layer communications. Modern wireless communica...
The Gluon Propagator without lattice Gribov copies
Alexandrou, C; Follana, E; Forcrand, Ph. de
2001-01-01
We study the gluon propagator on the lattice using the Laplacian gauge which is free of lattice Gribov copies. We compare our results with those obtained in the Landau gauge on the lattice, as well as with various approximate solutions of the Dyson Schwinger equations. We find a finite value $\\sim (250 \\rm{MeV})^{-2}$ for the zero-momentum propagator, and a pole mass $\\sim 640 \\pm 110$ MeV.
Experimental generation of optical coherence lattices
Energy Technology Data Exchange (ETDEWEB)
Chen, Yahong; Cai, Yangjian, E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [College of Physics, Optoelectronics and Energy and Collaborative Innovation Center of Suzhou Nano Science and Technology, Soochow University, Suzhou 215006 (China); Key Lab of Advanced Optical Manufacturing Technologies of Jiangsu Province and Key Lab of Modern Optical Technologies of Education Ministry of China, Soochow University, Suzhou 215006 (China); Ponomarenko, Sergey A., E-mail: serpo@dal.ca, E-mail: yangjiancai@suda.edu.cn [Department of Electrical and Computer Engineering, Dalhousie University, Halifax, Nova Scotia B3J 2X4 (Canada)
2016-08-08
We report experimental generation and measurement of recently introduced optical coherence lattices. The presented optical coherence lattice realization technique hinges on a superposition of mutually uncorrelated partially coherent Schell-model beams with tailored coherence properties. We show theoretically that information can be encoded into and, in principle, recovered from the lattice degree of coherence. Our results can find applications to image transmission and optical encryption.
An Intrinsic Topology for Orthomodular Lattices
Brunet, Olivier
2007-11-01
We present a general way to define a topology on orthomodular lattices. We show that in the case of a Hilbert lattice, this topology is equivalent to that induced by the metrics of the corresponding Hilbert space. Moreover, we show that in the case of a boolean algebra, the obtained topology is the discrete one. Thus, our construction provides a general tool for studying orthomodular lattices but also a way to distinguish classical and quantum logics.
International Nuclear Information System (INIS)
Richter, W.
1976-01-01
α-rhombohedral boron is the simplest boron modification, with only 12 atoms per unit cell. The boron atoms are arranged in B 12 icosahedra, which are centered at the lattice points of a primitive rhombohedral lattice. The icosahedra are slightly deformed, as the five-fold symmetry of the ideal icosahedron is incompatible with any crystal structure. The lattice dynamics of α-boron are discussed in terms of the model developed by Weber and Thorpe. (Auth.)
Defect melting as an SO(3) lattice gauge theory
International Nuclear Information System (INIS)
Kleinert, H.
1982-01-01
We show that defect melting is closely related to SO(3) lattice gauge theory. The phase transition of this system corresponds to a Lindemann melting parameter L approx. equal to 50 γ where γ approx. equal to 2 is a parameter characterizing the unharmonic content in the elastic forces. This in rough agreement with experiment. The equivalence may help in visualizing the crucial role of defects in quark confinement. (orig.)
Lattice theory special topics and applications
Wehrung, Friedrich
George Grätzer's Lattice Theory: Foundation is his third book on lattice theory (General Lattice Theory, 1978, second edition, 1998). In 2009, Grätzer considered updating the second edition to reflect some exciting and deep developments. He soon realized that to lay the foundation, to survey the contemporary field, to pose research problems, would require more than one volume and more than one person. So Lattice Theory: Foundation provided the foundation. Now we complete this project with Lattice Theory: Special Topics and Applications, written by a distinguished group of experts, to cover some of the vast areas not in Foundation. This first volume is divided into three parts. Part I. Topology and Lattices includes two chapters by Klaus Keimel, Jimmie Lawson and Ales Pultr, Jiri Sichler. Part II. Special Classes of Finite Lattices comprises four chapters by Gabor Czedli, George Grätzer and Joseph P. S. Kung. Part III. Congruence Lattices of Infinite Lattices and Beyond includes four chapters by Friedrich W...
Testing the holographic principle using lattice simulations
Directory of Open Access Journals (Sweden)
Jha Raghav G.
2018-01-01
Full Text Available The lattice studies of maximally supersymmetric Yang-Mills (MSYM theory at strong coupling and large N is important for verifying gauge/gravity duality. Due to the progress made in the last decade, based on ideas from topological twisting and orbifolding, it is now possible to study these theories on the lattice while preserving an exact supersymmetry on the lattice. We present some results from the lattice studies of two-dimensional MSYM which is related to Type II supergravity. Our results agree with the thermodynamics of different black hole phases on the gravity side and the phase transition (Gregory–Laflamme between them.
The Developement of A Lattice Structured Database
DEFF Research Database (Denmark)
Bruun, Hans
In this project we have investigated the possibilities to make a system based on the concept algebra described in [3], [4] and [5]. The concept algebra is used for ontology specification and knowledge representation. It is a distributive lattice extended with attribution operations. One of the main...... to a given set of inserted terms, that is the smallest lattice where the inserted terms preserve their value compared to the value in the initial algebra/lattice. The database is the dual representation of this most disjoint lattice. We develop algorithms to construct and make queries to the database....
Cascade Baryon Spectrum from Lattice QCD
International Nuclear Information System (INIS)
Mathur, Nilmani; Bulava, John; Edwards, Robert; Engelson, Eric; Joo, Balint; Lichtl, Adam; Lin, Huey-Wen; Morningstar, Colin; Richards, David; Wallace, Stephen
2008-01-01
A comprehensive study of the cascade baryon spectrum using lattice QCD affords the prospect of predicting the masses of states not yet discovered experimentally, and determining the spin and parity of those states for which the quantum numbers are not yet known. The study of the cascades, containing two strange quarks, is particularly attractive for lattice QCD in that the chiral effects are reduced compared to states composed only of u/d quarks, and the states are typically narrow. We report preliminary results for the cascade spectrum obtained by using anisotropic Nf = 2 Wilson lattices with temporal lattice spacing 5.56 GeV?1.
Elastic lattice in an incommensurate background
International Nuclear Information System (INIS)
Dickman, R.; Chudnovsky, E.M.
1995-01-01
We study a harmonic triangular lattice, which relaxes in the presence of an incommensurate short-wavelength potential. Monte Carlo simulations reveal that the elastic lattice exhibits only short-ranged translational correlations, despite the absence of defects in either lattice. Extended orientational order, however, persists in the presence of the background. Translational correlation lengths exhibit approximate power-law dependence upon cooling rate and background strength. Our results may be relevant to Wigner crystals, atomic monolayers on crystals surfaces, and flux-line and magnetic bubble lattices
Holographic Lattices Give the Graviton a Mass
Blake, Mike; Vegh, David
2014-01-01
We discuss the DC conductivity of holographic theories with translational invariance broken by a background lattice. We show that the presence of the lattice induces an effective mass for the graviton via a gravitational version of the Higgs mechanism. This allows us to obtain, at leading order in the lattice strength, an analytic expression for the DC conductivity in terms of the size of the lattice at the horizon. In locally critical theories this leads to a power law resistivity that is in agreement with an earlier field theory analysis of Hartnoll and Hofman.
Polarization response of RHIC electron lens lattices
Directory of Open Access Journals (Sweden)
V. H. Ranjbar
2016-10-01
Full Text Available Depolarization response for a system of two orthogonal snakes at irrational tunes is studied in depth using lattice independent spin integration. In particular we consider the effect of overlapping spin resonances in this system, to understand the impact of phase, tune, relative location and threshold strengths of the spin resonances. These results are benchmarked and compared to two dimensional direct tracking results for the RHIC e-lens lattice and the standard lattice. Finally we consider the effect of longitudinal motion via chromatic scans using direct six dimensional lattice tracking.
DEFF Research Database (Denmark)
Stassis, C.; Zaretsky, J.; Misemer, D. K.;
1983-01-01
A large single crystal of FCC Ca was grown and was used to study the lattice dynamics of this divalent metal by coherent inelastic neutron scattering. The phonon dispersion curves were measured, at room temperature, along the [ξ00], [ξξ0], [ξξξ], and [0ξ1] symmetry directions. The dispersion curves...... to the propagation of elastic waves. The frequencies of the T1[ξξ0] branch for ξ between approximately 0.5 and 0.8 are slightly above the velocity-of-sound line determined from the low-frequency measurements. Since a similar effect has been observed in FCC Yb, it is natural to assume that the anomalous dispersion.......8, there is a relative decrease in the electronic screening of the vibrational motion of the nuclei, which may account for the positive dispersion exhibited by the T1 [ξξ0] branch in this range of ξ values. The data were used to evaluate the elastic constants, the phonon density of states, and the lattice specific heat...
Lattice dynamics in solid oxygen
International Nuclear Information System (INIS)
Kobashi, K.; Klein, M.L.; Chandrasekharan, V.
1979-01-01
Lattice dynamical calculations for the bulk α, β, and γ phases of solid O 2 and for the monolayer α and β phases have been made in the harmonic approximation. In the α and β phases, atom-atom 6-12 potentials are employed. In the γ phase, effective potentials are used between molecular centers and only the translational lattice vibrations are calculated. It is found that Laufer and Leroi's potential parameters give two k=O frequencies at 42.7 and 43.6 cm -1 in the bulk α-O 2 , and at 40.7 cm -1 for the degenerate k=0 modes in the β phase. The observed Raman lines for α-O 2 at 43 and 79 cm -1 , which are both known to exhibit isotope shifts, are thus tentatively assigned to an accidentally degenerate line and a two-phonon band, respectively, In view of the possible contribution from anharmonic effects, the agreement of the calculation with experiment (48-51 cm -1 ) in β-O 2 may be better than it seems. For the bulk γ-O 2 , a discrepancy is observed between the calculated elastic constants and those derived from Brillouin scattering experiments. This discrepancy may be due to the neglect of translation-rotation coupling. In the monolayer O 2 , Raman active modes at 28.3 and 40.6 cm -1 for the α phase, and 31.9 cm -1 for the β phase are predicted
Introduction to Vortex Lattice Theory
Directory of Open Access Journals (Sweden)
Santiago Pinzón
2015-10-01
Full Text Available Panel methods have been widely used in industry and are well established since the 1970s for aerodynamic analysis and computation. The Vortex Lattice Panel Method presented in this study comes across a sophisticated method that provides a quick solution time, allows rapid changes in geometry and suits well for aerodynamic analysis. The aerospace industry is highly competitive in design efficiency, and perhaps one of the most important factors on airplane design and engineering today is multidisciplinary optimization. Any cost reduction method in the design cycle of a product becomes vital in the success of its outcome. The subsequent sections of this article will further explain in depth the theory behind the vortex lattice method, and the reason behind its selection as the method for aerodynamic analysis during preliminary design work and computation within the aerospace industry. This article is analytic in nature, and its main objective is to present a mathematical summary of this widely used computational method in aerodynamics.
Noise and driving induced Brownian heat current in the Frenkel-Kontorova lattices
Chen, Chongyang; Chen, Ruyin; Nie, Linru; Wang, Chaojie; Jia, Youjian
2018-02-01
We investigate Brownian heat current induced by noise and driving in the heat conduction of Frenkel-Kontorova (FK) lattices, whose two ends contact respectively with two baths with temporally. Our numerical results indicate that thermal current of the system versus environmental reference temperature exhibits two peaks in symmetric cases, i.e., thermal SR. In asymmetric cases, the phenomenon also takes place, depending on on-site potentials of the atoms exerted on by the periodic signal, but disappears for harmonic lattices. Moreover, its intrinsic physical mechanism is analyzed in detail. The above results play important roles in controlling thermal current of nonlinear lattices.
Dorri, Mahyar; Hashemitabar, Shirin; Hosseinzadeh, Hossein
2018-01-10
Cinnamon (Cinnamomum zeylanicum, Lauraceae) is a food additive greatly used for its taste. However, recently this medicinal plant has been brought to attention due to its medical effects. Cinnamon has constituents such as cinnamaldehyde and cinnamic acid that offers some health benefits including antioxidant and free-radical scavenging properties, lowering of blood glucose, anti-cholesterolemic, analgesic, antimicrobial, anti-inflammatory, anti-yeast, anti-secretagogue, and anti-gastric ulcer effects. This review summarizes various in vitro and animal studies on the protective effects of cinnamon against natural and chemical toxins. These studies consider the antidotal and/or protective effects of cinnamon and its major constituents against natural toxins and chemical-induced toxicities. It has been mentioned that cinnamon and its main constituents can ameliorate the toxicity of chemical toxins in liver, kidney, blood, brain, embryo, reproductive system, heart, spleen in part through antioxidant effect, radical scavenging, reducing lipid peroxidation, anti-inflammatory, fungistatic and fungicidal activities, modulation of CK-MB, LDH, TNF-α, IL-6, mitogen-activated protein kinase (MAPK), and nuclear factor-ĸB (NF-ĸB) signaling pathways.
Siegert, Markus; Kranawetvogl, Andreas; Thiermann, Horst; John, Harald
2017-12-23
The banned chemical warfare agent sulfur mustard (SM) still represents a serious threat to civilians and military personnel. Therefore, identification of antidotes and scavengers is of high concern. One promising substance is glutathione (GSH). GSH is known to mitigate symptoms of SM poisoning in vitro and in vivo. However, the mechanism of action remains unclear with respect to physiological impact as well as chemical scavenging by reaction between GSH and SM. Therefore, a novel in vitro method was used to characterize the scavenging potential of GSH. Accordingly, alkylation of human serum albumin (HSA), which represents an established biomarker for SM intoxication, was used as a measure for remaining SM. Coincubation of GSH and SM in human serum was performed, and time-dependent degradation of SM was monitored in the presence and absence of GSH. Protein-derived and small molecular reaction products between GSH, HSA, and SM were analyzed using microbore liquid chromatography-electrospray ionization high-resolution tandem-mass spectrometry. Although covalent modification of GSH by SM was observed, measurements clearly documented no significant reduction of SM concentration in the presence of GSH. Accordingly, beneficial therapeutic mechanisms of GSH in the case of SM poisoning would appear to be based on physiological effects than on chemical scavenging. Copyright © 2017 Elsevier B.V. All rights reserved.
Wyer, Peter C; Alves Silva, Suzana; Post, Stephen G; Quinlan, Patricia
2014-12-01
Contemporary health care is increasing in complexity and lacks a unifying understanding of epistemology, methodology and goals. Lack of conceptual consistency in concepts such as 'patient-centred care' (PCC) typifies system-wide discordance. We contrast the fragmented descriptions of PCC and related tools to its own origins in the writings of Balint and to a subsequent construct, relationship-centred care (RCC). We identify the explicit and elaborated connection between RCC and a defined epistemological foundation as a distinguishing feature of the construct and we demonstrate that this makes possible the recognition of alignments between RCC and independently developed constructs. Among these, we emphasize Schon's reflective practice, Nonaka's theory of organizational knowledge creation and the research methodology of realist synthesis. We highlight the relational principles common to these domains and to their common epistemologies and illustrate unsatisfying consequences of adherence to less adequate epistemological frameworks such as positivism. We offer RCC not as an 'antidote' to the dilemmas identified at the outset but as an example that illuminates the value and importance of explicit identification of the premises and assumptions underlying approaches to improvement of the health care system. We stress the potential value of identifying epistemological affinities across otherwise disparate fields and disciplines. © 2014 John Wiley & Sons, Ltd.
Soltani, Motahareh; Shetab-Boushehri, Seyed F; Shetab-Boushehri, Seyed V
2016-08-01
Aluminium phosphide (AlP) is a fumigant pesticide which protects stored grains from insects and rodents. When it comes into contact with moisture, AlP releases phosphine (PH3), a highly toxic gas. No efficient antidote has been found for AlP poisoning so far and most people who are poisoned do not survive. Boric acid is a Lewis acid with an empty p orbital which accepts electrons. This study aimed to investigate the neutralisation of PH3 gas with boric acid. This study was carried out at the Baharlou Hospital, Tehran University of Medical Sciences, Tehran, Iran, between December 2013 and February 2014. The volume of released gas, rate of gas evolution and changes in pH were measured during reactions of AlP tablets with water, acidified water, saturated boric acid solution, acidified saturated boric acid solution, activated charcoal and acidified activated charcoal. Infrared spectroscopy was used to study the resulting probable adduct between PH3 and boric acid. Activated charcoal significantly reduced the volume of released gas (P poisoning.
Non-equilibrium dynamics of ultracold atoms in optical lattices
Chen, David
This thesis describes experiments focused on investigating out-of-equilibrium phenomena in the Bose-Hubbard Model and exploring novel cooling techniques for ultracold gases in optical lattices. In the first experiment, we study quenches across the Mott-insulator-to-superfluid quantum phase transition in the 3D Bose-Hubbard Model. The quench is accomplished by continuously tuning the ratio of the Hubbard energies. We observe that the degree of excitation is proportional to the fraction of atoms that cross the phase boundary, and that the amount of excitations and energy produced during the quench have a power-law dependence on the quench rate. These phenomena suggest an excitation process analogous to the mechanism for defect generation in non-equilibrium classical phase transitions. This experiment constitutes the first observation of the Kibble-Zurek mechanism in a quantum quench. We have reported our findings in Ref. [1]. In a second experiment, published in Ref. [2], we investigate dissipation as a method for cooling a strongly interacting gas. We introduce dissipation via a bosonic reservoir to a strongly interacting bosonic gas in the Mott-insulator regime of a 3D spin-dependent optical lattice. The lattice atoms are excited to a higher energy band using laser-induced Bragg transitions. A weakly interacting superfluid comprised of atoms in a state that does not experience the lattice potential acts as a dissipative bath that interacts with the lattice atoms through collisions. We measure the resulting bath-induced decay using the atomic quasimomentum distribution, and we compare the decay rate with predictions from a weakly interacting model with no free parameters. A competing intrinsic decay mechanism arising from collisions between lattice atoms is also investigated. The presence of intrinsic decay can not be accommodated within a non-interacting framework and signals that strong interactions may play a central role in the lattice-atom dynamics. The
Lattices for laymen: a non-specialist's introduction to lattice gauge theory
International Nuclear Information System (INIS)
Callaway, D.J.E.
1985-01-01
The review on lattice gauge theory is based upon a series of lectures given to the Materials Science and Technology Division at Argonne National Laboratory. Firstly the structure of gauge theories in the continuum is discussed. Then the lattice formulation of these theories is presented, including quantum electrodynamics and non-abelian lattice gauge theories. (U.K.)
Hadron physics from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Schaefer, Andreas [Regensburg Univ. (Germany). Inst. for Theoretical Physics
2016-11-01
Particle physics experiments at modern high luminosity particle accelerators achieve orders of magnitude higher count rates than what was possible ten or twenty years ago. This extremely large statistics allows to draw far reaching conclusions even from minute signals, provided that these signals are well understood by theory. This is, however, ever more difficult to achieve. Presently, technical and scientific progress in general and experimental progress in particle physics in particular, shows typically an exponential growth rate. For example, data acquisition and analysis are, among many other factor, driven by the development of ever more efficient computers and thus by Moore's law. Theory has to keep up with this development by also achieving an exponential increase in precision, which is only possible using powerful computers. This is true for both types of calculations, analytic ones as, e.g., in quantum field perturbation theory, and purely numerical ones as in Lattice QCD. As stated above such calculations are absolutely indispensable to make best use of the extremely costly large particle physics experiments. Thus, it is economically reasonable to invest a certain percentage of the cost of accelerators and experiments in related theory efforts. The basic ideas behind Lattice QCD simulations are the following: Because quarks and gluons can never be observed individually but are always ''confined'' into colorless hadrons, like the proton, all quark-gluon states can be expressed in two different systems of basis states, namely in a quark-gluon basis and the basis of hadron states. The proton, e.g., is an eigenstate of the latter, a specific quark-gluon configuration is part of the former. In the quark-gluon basis a physical hadron, like a proton, is given by an extremely complicated multi-particle wave function containing all effects of quantum fluctuations. This state is so complicated that it is basically impossible to model it
MILLER, KATHLEEN
2011-01-01
During the Great Plague of London (1665), William Winstanley veered from his better known roles as arbiter of success and failure in his works of biography or as a comic author under the pseudonym Poor Robin, and instead engaged with his reading audience as a plague writer in the rare book The Christians Refuge: Or Heavenly Antidotes Against the Plague in this Time of Generall Contagion to Which is Added the Charitable Physician (1665). From its extensive paratexts, including a table of mortality statistics and woodcut of king death, to its temporal and providential interpretation of the disease between the covers of a single text, The Christians Refuge is a compendium of contemporary understanding of plague. This article addresses The Christians Refuge as an expression of London’s print marketplace in a moment of transformation precipitated by the epidemic. The author considers the paratextual elements in The Christians Refuge that engage with the presiding norms in plague writing and publishing in 1665 and also explores how Winstanley’s authorship is expressed in the work. Winstanley has long been seen as a biographer or as a humour writer; attributing The Christians Refuge extends and challenges previous perceptions of his work. PMID:21461312
International Nuclear Information System (INIS)
Biner, S.B.; Rao, Weifeng; Zhang, Yongfeng
2016-01-01
In the first part of this study, the stability of Cu precipitates, up to 2 nm in diameter, in Fe-1at%Cu-1at%Ni-1at%Mn system was evaluated within the framework of phase-field modeling by utilizing a thermodynamic database. The implanted precipitates either in isolated or in clustered arrangements, were unstable and dissolved into the matrix. The dissolution rate decreases with increasing precipitate size; however, it is strongly influenced by the spatial arrangements of the implants and the overall alloy content. In the second part, the precipitation/segregation behavior at a circular dislocation, and square prismatic loops was parametrically studied. While precipitates formed at the dislocation loop, a significant segregation of Cu was observed at prismatic loops with either vacancy or interstitial character. Although, the both types of prismatic loops provide the spatial evolution of the stress-fields with the same absolute magnitude, the vacancy loops appears to be stronger sinks and their sink strength increases with decreasing loop size. The results clearly show the necessity of inclusion of the underlying lattice defects in the microstructure modeling of materials under the irradiation environments.
Biner, S. B.; Rao, Weifeng; Zhang, Yongfeng
2016-01-01
In the first part of this study, the stability of Cu precipitates, up to 2 nm in diameter, in Fe-1at%Cu-1at%Ni-1at%Mn system was evaluated within the framework of phase-field modeling by utilizing a thermodynamic database. The implanted precipitates either in isolated or in clustered arrangements, were unstable and dissolved into the matrix. The dissolution rate decreases with increasing precipitate size; however, it is strongly influenced by the spatial arrangements of the implants and the overall alloy content. In the second part, the precipitation/segregation behavior at a circular dislocation, and square prismatic loops was parametrically studied. While precipitates formed at the dislocation loop, a significant segregation of Cu was observed at prismatic loops with either vacancy or interstitial character. Although, the both types of prismatic loops provide the spatial evolution of the stress-fields with the same absolute magnitude, the vacancy loops appears to be stronger sinks and their sink strength increases with decreasing loop size. The results clearly show the necessity of inclusion of the underlying lattice defects in the microstructure modeling of materials under the irradiation environments.
More than Just Another Course: Service Learning as Antidote to Cultural Bias
Gökmenoglu, Tuba
2017-01-01
The social influence role of teachers and their awareness of their responsibilities towards society are as important as their subject matter and pedagogical knowledge. As a multilevel learning environment, teacher colleges should place significant emphasis on enhancing teacher candidates' social responsibility attitudes, knowledge, and skills. To…
2006-09-01
A. M. Hossini, L. F. Fecker, C. E. Orfanos, and B. Tebbe (2002). The role of nuclear factor-kappa B and melanogenesis in tumor necrosis factor...chemical warfare agents. A further goal in conjunction with consortium members is to design rat and mouse microarrays and QPCR reagents , which will be
Monte Carlo lattice program KIM
International Nuclear Information System (INIS)
Cupini, E.; De Matteis, A.; Simonini, R.
1980-01-01
The Monte Carlo program KIM solves the steady-state linear neutron transport equation for a fixed-source problem or, by successive fixed-source runs, for the eigenvalue problem, in a two-dimensional thermal reactor lattice. Fluxes and reaction rates are the main quantities computed by the program, from which power distribution and few-group averaged cross sections are derived. The simulation ranges from 10 MeV to zero and includes anisotropic and inelastic scattering in the fast energy region, the epithermal Doppler broadening of the resonances of some nuclides, and the thermalization phenomenon by taking into account the thermal velocity distribution of some molecules. Besides the well known combinatorial geometry, the program allows complex configurations to be represented by a discrete set of points, an approach greatly improving calculation speed
Weak transitions in lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Maturana, G.
1984-01-01
Some techniques to calculate the effects of the strong interactions on the matrix elements of weak processes are described. The lattice formulation of Quantum Chromodynamics is used to account for the low energy gluons, and the corresponding numerical methods are explained. The high energy contributions are included in effective lagrangians and the problem of matching the different scales related to the renormalization of the operators and wavefunctions is also discussed. The ..delta..l = 1/2 enhancement rule and the K/sup 0/-anti-K/sup 0/ are used to illustrate these techniques and the results of a numerical calculation is reported. The values obtained are very encouraging and they certainly show good qualitative agreement with the experimental values. The emphasis is on general techniques, and in particular, several improvements to this particular calculation are proposed.
Müller, H.-M.; Koonin, S. E.; Seki, R.; van Kolck, U.
2000-04-01
We investigate nuclear matter on a cubic lattice. An exact thermal formalism is applied to nucleons with a Hamiltonian that accommodates on-site and next-neighbor parts of the central, spin-, and isospin-exchange interactions. We describe the nuclear matter Monte Carlo methods which contain elements from shell model Monte Carlo methods and from numerical simulations of the Hubbard model. We show that energy and basic saturation properties of nuclear matter can be reproduced. Evidence of a first-order phase transition from an uncorrelated Fermi gas to a clustered system is observed by computing mechanical and thermodynamical quantities such as compressibility, heat capacity, entropy, and grand potential. We compare symmetry energy and first sound velocities with literature and find reasonable agreement.
Pion structure from lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Javadi Motaghi, Narjes
2015-05-12
In this thesis we use lattice QCD to compute the second Mellin moments of pion generalized parton distributions and pion electromagnetic form factors. For our calculations we are able to analyze a large set of gauge configurations with 2 dynamical flavours using non-perturbatively the improved Wilson-Sheikholeslami-Wohlert fermionic action pion masses ranging down to 151 MeV. By employing improved smearing we were able to suppress excited state contamination. However, our data in the physical quark mass limit show that some excited state contamination remains. We show the non-zero sink momentum is optimal for the computation of the electromagnetic form factors and generalized form factors at finite momenta.
Particle states of lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Kapoyannis, A.S.; Panagiotou, A.D. [University of Athens, Nuclear and Particle Physics Section, Faculty of Physics, Athens (Greece)
2017-11-15
We determine the degeneracy factor and the average particle mass of particles that produce the lattice QCD pressure and specific entropy at zero baryon chemical potential. The number of states of the gluons and the quarks are found to converge above T = 230 MeV to almost constant values, close to the number of states of an ideal quark-gluon phase, while their assigned masses retain high values. The number of states and the average mass of a system containing quarks in interaction with gluons are found to decrease steeply with increase of temperature between T ∝ 150 and 160 MeV, a region contained within the region of the chiral transition. The minimum value of the number of states within this temperature interval indicates that the states are of hadronic nature. (orig.)
Lattice studies of hadrons with heavy flavors
Aubin, C.
2009-01-01
I will discuss recent developments in lattice studies of hadrons composed of heavy quarks. I will mostly cover topics which are at a state of direct comparison with experiment, but will also discuss new ideas and promising techniques to aid future studies of lattice heavy quark physics.
Lattice Boltzmann scheme for relativistic fluids
Mendoza, M.; Boghosian, B.; Herrmann, H. J.; Succi, S.
2009-01-01
A Lattice Boltzmann formulation for relativistic fluids is presented and numerically verified through quantitative comparison with recent hydrodynamic simulations of relativistic shock-wave propagation in viscous quark-gluon plasmas. This formulation opens up the possibility of exporting the main advantages of Lattice Boltzmann methods to the relativistic context, which seems particularly useful for the simulation of relativistic fluids in complicated geometries.
Lattice dynamics of ferromagnetic superconductor UGe2
Indian Academy of Sciences (India)
This paper reports the lattice dynamical study of the UGe2 using a lattice dynamical model theory based on pairwise interactions under the framework of the shell model. The calculated phonon dispersion curves and phonon density of states are in good agreement with the measured data.
The contact polytope of the leech lattice
Sikiric, M.D.; Schürmann, A.; Vallentin, F.
2010-01-01
The contact polytope of a lattice is the convex hull of its shortest vectors. In this paper we classify the facets of the contact polytope of the Leech lattice up to symmetry. There are 1, 197, 362, 269, 604, 214, 277, 200 many facets in 232 orbits.
The contact polytope of the Leech lattice
M. Dutour Sikiric; A. Schuermann; F. Vallentin (Frank)
2010-01-01
htmlabstractThe contact polytope of a lattice is the convex hull of its shortest vectors. In this paper we classify the facets of the contact polytope of the Leech lattice up to symmetry. There are 1,197,362,269,604,214,277,200 many facets in 232 orbits.
The contact polytope of the Leech lattice
M. Dutour Sikiric; A. Schuermann; F. Vallentin (Frank)
2009-01-01
htmlabstractThe contact polytope of a lattice is the convex hull of its shortest vectors. In this paper we classify the facets of the contact polytope of the Leech lattice up to symmetry. There are 1,197,362,269,604,214,277,200 many facets in 232 orbits.
An Application of Linear Algebra over Lattices
Directory of Open Access Journals (Sweden)
M. Hosseinyazdi
2008-03-01
Full Text Available In this paper, first we consider L n as a semimodule over a complete bounded distributive lattice L. Then we define the basic concepts of module theory for L n. After that, we proved many similar theorems in linear algebra for the space L n. An application of linear algebra over lattices for solving linear systems, was given
Lattice-Valued Possibilistic Entropy Measure
Czech Academy of Sciences Publication Activity Database
Kramosil, Ivan
2008-01-01
Roč. 16, č. 6 (2008), s. 829-846 ISSN 0218-4885 R&D Projects: GA AV ČR IAA100300503 Institutional research plan: CEZ:AV0Z10300504 Keywords : complete lattice * lattice-valued possibilistic distribution * entropy measure * product of possibilistic distribution Subject RIV: BA - General Mathematics Impact factor: 1.000, year: 2008
Abelian gauge potentials on cubic lattices
DEFF Research Database (Denmark)
Burrello, M.; Lepori, L.; Paganelli, S.
2017-01-01
fields in a system of ultracold atoms in optical lattices. After reviewing two of the main experimental schemes for the physical realization of synthetic gauge potentials in ultracold setups, we study cubic lattice tight-bindingmodels with commensurate flux.We finally discuss applications of gauge...
Selective nanoscale growth of lattice mismatched materials
Energy Technology Data Exchange (ETDEWEB)
Lee, Seung-Chang; Brueck, Steven R. J.
2017-06-20
Exemplary embodiments provide materials and methods of forming high-quality semiconductor devices using lattice-mismatched materials. In one embodiment, a composite film including one or more substantially-single-particle-thick nanoparticle layers can be deposited over a substrate as a nanoscale selective growth mask for epitaxially growing lattice-mismatched materials over the substrate.
The mystery of the fifteenth Bravais lattice
Nussbaum, Allen
2000-10-01
An understanding of the principles of crystal structure is necessary for the study of solids. There are contradictions in the literature dealing with the nature of crystal lattices, and there is also a miscounting of the number of possible lattices. This paper clarifies the situation in a systematic and simple way.
Minimal Varieties of Representable Commutative Residuated Lattices
Czech Academy of Sciences Publication Activity Database
Horčík, Rostislav
2012-01-01
Roč. 100, č. 6 (2012), s. 1063-1078 ISSN 0039-3215 R&D Projects: GA ČR GAP202/10/1826 Institutional research plan: CEZ:AV0Z10300504 Keywords : commutative residuated lattice * subvariety lattice * minimal variety * substructural logic * maximally consistent logic Subject RIV: BA - General Mathematics Impact factor: 0.342, year: 2012
The Chroma Software System for Lattice QCD
International Nuclear Information System (INIS)
Edwards, Robert G.; Joo, Balint
2005-01-01
We describe aspects of the Chroma software for lattice QCD calculations. Chroma is an open source C++ based software system developed using the software infrastructure of the US SciDAC initiative. Chroma interfaces with output from the BAGEL assembly generator for optimised lattice fermion kernels on some architectures. It can be run on workstations, clusters and the QCDOC supercomputer
The Chroma Software System for Lattice QCD
International Nuclear Information System (INIS)
Robert Edwards; Balint Joo
2004-01-01
We describe aspects of the Chroma software system for lattice QCD calculations. Chroma is an open source C++ based software system developed using the software infrastructure of the US SciDAC initiative. Chroma interfaces with output from the BAGEL assembly generator for optimized lattice fermion kernels on some architectures. It can be run on workstations, clusters and the QCDOC supercomputer
Gap solitons in Rabi lattices.
Chen, Zhaopin; Malomed, Boris A
2017-03-01
We introduce a two-component one-dimensional system, which is based on two nonlinear Schrödinger or Gross-Pitaevskii equations (GPEs) with spatially periodic modulation of linear coupling ("Rabi lattice") and self-repulsive nonlinearity. The system may be realized in a binary Bose-Einstein condensate, whose components are resonantly coupled by a standing optical wave, as well as in terms of the bimodal light propagation in periodically twisted waveguides. The system supports various types of gap solitons (GSs), which are constructed, and their stability is investigated, in the first two finite bandgaps of the underlying spectrum. These include on- and off-site-centered solitons (the GSs of the off-site type are additionally categorized as spatially even and odd ones), which may be symmetric or antisymmetric, with respect to the coupled components. The GSs are chiefly stable in the first finite bandgap and unstable in the second one. In addition to that, there are narrow regions near the right edge of the first bandgap, and in the second one, which feature intricate alternation of stability and instability. Unstable solitons evolve into robust breathers or spatially confined turbulent modes. On-site-centered GSs are also considered in a version of the system that is made asymmetric by the Zeeman effect, or by birefringence of the optical waveguide. A region of alternate stability is found in the latter case too. In the limit of strong asymmetry, GSs are obtained in a semianalytical approximation, which reduces two coupled GPEs to a single one with an effective lattice potential.
Chen, Zhaopin; Malomed, Boris A.
2017-03-01
We introduce a two-component one-dimensional system, which is based on two nonlinear Schrödinger or Gross-Pitaevskii equations (GPEs) with spatially periodic modulation of linear coupling ("Rabi lattice") and self-repulsive nonlinearity. The system may be realized in a binary Bose-Einstein condensate, whose components are resonantly coupled by a standing optical wave, as well as in terms of the bimodal light propagation in periodically twisted waveguides. The system supports various types of gap solitons (GSs), which are constructed, and their stability is investigated, in the first two finite bandgaps of the underlying spectrum. These include on- and off-site-centered solitons (the GSs of the off-site type are additionally categorized as spatially even and odd ones), which may be symmetric or antisymmetric, with respect to the coupled components. The GSs are chiefly stable in the first finite bandgap and unstable in the second one. In addition to that, there are narrow regions near the right edge of the first bandgap, and in the second one, which feature intricate alternation of stability and instability. Unstable solitons evolve into robust breathers or spatially confined turbulent modes. On-site-centered GSs are also considered in a version of the system that is made asymmetric by the Zeeman effect, or by birefringence of the optical waveguide. A region of alternate stability is found in the latter case too. In the limit of strong asymmetry, GSs are obtained in a semianalytical approximation, which reduces two coupled GPEs to a single one with an effective lattice potential.
Cold collisions in dissipative optical lattices
International Nuclear Information System (INIS)
Piilo, J; Suominen, K-A
2005-01-01
The invention of laser cooling methods for neutral atoms allows optical and magnetic trapping of cold atomic clouds in the temperature regime below 1 mK. In the past, light-assisted cold collisions between laser cooled atoms have been widely studied in magneto-optical atom traps (MOTs). We describe here theoretical studies of dynamical interactions, specifically cold collisions, between atoms trapped in near-resonant, dissipative optical lattices. The extension of collision studies to the regime of optical lattices introduces several complicating factors. For the lattice studies, one has to account for the internal substates of atoms, position-dependent matter-light coupling, and position-dependent couplings between the atoms, in addition to the spontaneous decay of electronically excited atomic states. The developed one-dimensional quantum-mechanical model combines atomic cooling and collision dynamics in a single framework. The model is based on Monte Carlo wavefunction simulations and is applied when the lattice-creating lasers have frequencies both below (red-detuned lattice) and above (blue-detuned lattice) the atomic resonance frequency. It turns out that the radiative heating mechanism affects the dynamics of atomic cloud in a red-detuned lattice in a way that is not directly expected from the MOT studies. The optical lattice and position-dependent light-matter coupling introduces selectivity of collision partners. The atoms which are most mobile and energetic are strongly favoured to participate in collisions, and are more often ejected from the lattice, than the slow ones in the laser parameter region selected for study. Consequently, the atoms remaining in the lattice have a smaller average kinetic energy per atom than in the case of non-interacting atoms. For blue-detuned lattices, we study how optical shielding emerges as a natural part of the lattice and look for ways to optimize the effect. We find that the cooling and shielding dynamics do not mix
Atom interferometry using a shaken optical lattice
Weidner, C. A.; Yu, Hoon; Kosloff, Ronnie; Anderson, Dana Z.
2017-04-01
We introduce shaken lattice interferometry with atoms trapped in a one-dimensional optical lattice. By phase modulating (shaking) the lattice, we control the momentum state of the atoms. Through a sequence of shaking functions, the atoms undergo an interferometer sequence of splitting, propagation, reflection, reverse propagation, and recombination. Each shaking function in the sequence is optimized with a genetic algorithm to achieve the desired momentum state transitions. As with conventional atom interferometers, the sensitivity of the shaken lattice interferometer increases with interrogation time. The shaken lattice interferometer may also be optimized to sense signals of interest while rejecting others, such as the measurement of an ac inertial signal in the presence of an unwanted dc signal.
Synthesizing lattice structures in phase space
International Nuclear Information System (INIS)
Guo, Lingzhen; Marthaler, Michael
2016-01-01
In one dimensional systems, it is possible to create periodic structures in phase space through driving, which is called phase space crystals (Guo et al 2013 Phys. Rev. Lett. 111 205303). This is possible even if for particles trapped in a potential without periodicity. In this paper we discuss ultracold atoms in a driven optical lattice, which is a realization of such a phase space crystals. The corresponding lattice structure in phase space is complex and contains rich physics. A phase space lattice differs fundamentally from a lattice in real space, because its coordinate system, i.e., phase space, has a noncommutative geometry, which naturally provides an artificial gauge (magnetic) field. We study the behavior of the quasienergy band structure and investigate the dissipative dynamics. Synthesizing lattice structures in phase space provides a new platform to simulate the condensed matter phenomena and study the intriguing phenomena of driven systems far away from equilibrium. (paper)
A lattice approach to spinorial quantum gravity
Renteln, Paul; Smolin, Lee
1989-01-01
A new lattice regularization of quantum general relativity based on Ashtekar's reformulation of Hamiltonian general relativity is presented. In this form, quantum states of the gravitational field are represented within the physical Hilbert space of a Kogut-Susskind lattice gauge theory. The gauge field of the theory is a complexified SU(2) connection which is the gravitational connection for left-handed spinor fields. The physical states of the gravitational field are those which are annihilated by additional constraints which correspond to the four constraints of general relativity. Lattice versions of these constraints are constructed. Those corresponding to the three-dimensional diffeomorphism generators move states associated with Wilson loops around on the lattice. The lattice Hamiltonian constraint has a simple form, and a correspondingly simple interpretation: it is an operator which cuts and joins Wilson loops at points of intersection.
Supersymmetry on a space-time lattice
International Nuclear Information System (INIS)
Kaestner, Tobias
2008-01-01
In this thesis the WZ model in one and two dimensions has been thoroughly investigated. With the help of the Nicolai map it was possible to construct supersymmetrically improved lattice actions that preserve one of several supersymmetries. For the WZ model in one dimension SLAC fermions were utilized for the first time leading to a near-perfect elimination of lattice artifacts. In addition the lattice superpotential does not get modified which in two dimensions becomes important when further (discrete) symmetries of the continuum action are considered. For Wilson fermions two new improvements have been suggested and were shown to yield far better results than standard Wilson fermions concerning lattice artifacts. In the one-dimensional theory Ward Identities were studied.However, supersymmetry violations due to broken supersymmetry could only be detected at coarse lattices and very strong couplings. For the two-dimensional models a detailed analysis of supersymmetric improvement terms was given, both for Wilson and SLAC fermions. (orig.)
Lattice gravity near the continuum limit
International Nuclear Information System (INIS)
Feinberg, G.; Friedberg, R.; Lee, T.D.; Ren, H.C.
1984-01-01
We prove that the lattice gravity always approaches the usual continuum limit when the link length l -> 0, provided that certain general boundary conditions are satisfied. This result holds for any lattice, regular or irregular. Furthermore, for a given lattice, the deviation from its continuum limit can be expressed as a power series in l 2 . General formulas for such a perturbative calculation are given, together with a number of illustrative examples, including the graviton propagator. The lattice gravity satisfies all the invariance properties of Einstein's theory of general relativity. In addition, it is symmetric under a new class of transformations that are absent in the usual continuum theory. The possibility that the lattice theory (with a nonzero l) may be more fundamental is discussed. (orig.)
Interstructure Lattices and Types of Peano Arithmetic
Abdul-Quader, Athar
The collection of elementary substructures of a model of PA forms a lattice, and is referred to as the substructure lattice of the model. In this thesis, we study substructure and interstructure lattices of models of PA. We apply techniques used in studying these lattices to other problems in the model theory of PA. In Chapter 2, we study a problem that had its origin in Simpson ([Sim74]), who used arithmetic forcing to show that every countable model of PA has an expansion to PA* that is pointwise definable. Enayat ([Ena88]) later showed that there are 2N0 models with the property that every expansion to PA* is pointwise definable. In this Chapter, we use techniques involved in representations of lattices to show that there is a model of PA with this property which contains an infinite descending chain of elementary cuts. In Chapter 3, we study the question of when subsets can be coded in elementary end extensions with prescribed interstructure lattices. This problem originated in Gaifman [Gai76], who showed that every model of PA has a conservative, minimal elementary end extension. That is, every model of PA has a minimal elementary end extension which codes only definable sets. Kossak and Paris [KP92] showed that if a model is countable and a subset X can be coded in any elementary end extension, then it can be coded in a minimal extension. Schmerl ([Sch14] and [Sch15]) extended this work by considering which collections of sets can be the sets coded in a minimal elementary end extension. In this Chapter, we extend this work to other lattices. We study two questions: given a countable model M, which sets can be coded in an elementary end extension such that the interstructure lattice is some prescribed finite distributive lattice; and, given an arbitrary model M, which sets can be coded in an elementary end extension whose interstructure lattice is a finite Boolean algebra?
Light-induced lattice expansion leads to high-efficiency and stable perovskite solar cells
Energy Technology Data Exchange (ETDEWEB)
Tsai, Hsinhan; Asadpour, Reza; Blancon, Jean-Christophe; Stoumpos, Constantinos C.; Durand, Oliver; Strzalka, Joseph W.; Ajayan, Pulickel M.; Tretiak, Sergei; Even, Jacky; Nie, Wanyi; Mohite, Aditya D.
2018-04-05
Hybrid-perovskite based high-performance optoelectronic devices and clues from their operation has led to the realization that light-induced structural dynamics play a vital role on their physical properties, device performance and stability. Here, we report that continuous light illumination leads to a uniform lattice expansion in hybrid perovskite thin-films, which is critical for obtaining high-efficiency photovoltaic devices. Correlated, in-situ structural and device characterizations reveal that light-induced lattice expansion significantly benefits the performances of a mixed-cation pure-halide planar device, boosting the power conversion efficiency from 18.5% to 20.5%. This is a direct consequence of the relaxation of local lattice strains during lattice expansion, which results in the reduction of the energetic barriers at the perovskite/contact interfaces in devices, thus improving the open circuit voltage and fill factor. The light-induced lattice expansion stabilizes these high-efficiency photovoltaic devices under continuous operation of full-spectrum 1-Sun illumination for over 1500 hours. One Sentence Summary: Light-induced lattice expansion improves crystallinity, relaxes lattice strain, which enhances photovoltaic performance in hybrid perovskite device.
Quantum Simulation of Frustrated Classical Magnetism in Triangular Optical Lattices
Struck, J.; Ölschläger, C.; Le Targat, R.; Soltan-Panahi, P.; Eckardt, A.; Lewenstein, M.; Windpassinger, P.; Sengstock, K.
2011-08-01
Magnetism plays a key role in modern technology and stimulates research in several branches of condensed matter physics. Although the theory of classical magnetism is well developed, the demonstration of a widely tunable experimental system has remained an elusive goal. Here, we present the realization of a large-scale simulator for classical magnetism on a triangular lattice by exploiting the particular properties of a quantum system. We use the motional degrees of freedom of atoms trapped in an optical lattice to simulate a large variety of magnetic phases: ferromagnetic, antiferromagnetic, and even frustrated spin configurations. A rich phase diagram is revealed with different types of phase transitions. Our results provide a route to study highly debated phases like spin-liquids as well as the dynamics of quantum phase transitions.
Pehrsson, S; Johansson, K J; Janefeldt, A; Sandinge, A-S; Maqbool, S; Goodman, J; Sanchez, J; Almquist, J; Gennemark, P; Nylander, S
2017-06-01
Essentials MEDI2452 is a specific antidote of the platelet P2Y 12 receptor antagonist ticagrelor. Hemostatic effects of MEDI2452 were evaluated in pigs treated with ticagrelor and aspirin. MEDI2452 eliminated free ticagrelor within 5 min and gradually normalized platelet aggregation. Improvements in blood pressure (significant) and in blood-loss and survival (non-significant) were observed. Background Ticagrelor, a P2Y 12 antagonist, is approved for the prevention of thromboembolic events. However, antiplatelet therapies carry a risk of bleeding. Objective To explore the hemostatic effects of MEDI2452, an antidote for ticagrelor. Methods Pigs, pre-treated with aspirin, were given an intravenous infusion of ticagrelor or vehicle. At the end of the infusion, a piece of a liver lobe was cut off and a bolus of MEDI2452 or vehicle was administered intravenously. Blood was collected to monitor blood loss, mean arterial blood pressure (MAP) was recorded and survival time was observed over 4 h. Blood samples for drug plasma exposures and platelet aggregation were collected. Results MEDI2452 eliminated the free concentrations of ticagrelor and its active metabolite AR-C124910XX within 5 min. ADP-induced platelet aggregation was close to normal at 60 min, which was not significantly different from aspirin alone. MEDI2452 numerically reduced ticagrelor-mediated effects: body-weight-adjusted blood loss in the 15- to 90-min interval, 12 (confidence interval [CI] 95% 7-28] vs. 17 (CI 95% 5-31) (ticagrelor and aspirin) vs. 5 (CI 95% 3-9) mL kg -1 (aspirin alone), survival 70% (CI 95% 47-100) vs. 45% (CI 95% 21-92) (ticagrelor and aspirin) vs. 100% (CI 95% 100-100) (aspirin alone), and median survival time, 240 (CI 95% 180-240) vs. 169 (CI 95% 64-240) (ticagrelor and aspirin) vs. 240 (CI 95% 240-240) min (aspirin alone). Finally, MEDI2452 significantly attenuated the decline in MAP, 0.08 (CI 95% 0.07-0.09) vs. 0.141 (CI 95% 0.135-0.148) (ticagrelor and aspirin) vs. 0.04 (CI 95% 0
Directory of Open Access Journals (Sweden)
Chidi Uzoma Igwe
2016-11-01
Full Text Available Objective: To investigate the effects of coconut water intake on lipid profile and atherogenic predictor indices of albino rabbits overdosed with paracetamol using standard methods. Methods: Thirty-five albino rabbits weighing between 800–1200 g and aged between 2 and 3 months, were divided into 7 groups (I–VII of 5 animals each. Groups I, II and III were orally administered distilled water (20 mL/kg body weight, coconut water (20 mL/kg body weight and paracetamol (1000 mg/kg body weight respectively, for 7 days. Groups IV and V were administered coconut water (20 mL/kg body weight and silymarin (35 mg/kg body weight, respectively, for 6 days, then paracetamol (1000 mg/kg body weight on the 7th day. Groups VI and VII were administered distilled water for 6 days, paracetamol on the 7th day, then coconut water and silymarin, respectively, after 3 h. Results: The results showed that paracetamol overdose significantly reduced (P < 0.05 the mean body weight of the animals, increased the concentrations of serum total cholesterol, triacylglycerol, very low density lipoprotein cholesterol, low density lipoprotein cholesterol and the atherogenic predictor indices but reduced the serum high density lipoprotein cholesterol concentration of the animals relative to the control. The observed changes in the lipid profile and atherogenic predictor indices were countered more by post- than pre-treatment with coconut water and silymarin. Conclusions: The results indicated that coconut water acted as an effective antidote to paracetamol overdose-induced lipid abnormality in animals.
Commensurability effects in holographic homogeneous lattices
International Nuclear Information System (INIS)
Andrade, Tomas; Krikun, Alexander
2016-01-01
An interesting application of the gauge/gravity duality to condensed matter physics is the description of a lattice via breaking translational invariance on the gravity side. By making use of global symmetries, it is possible to do so without scarifying homogeneity of the pertinent bulk solutions, which we thus term as “homogeneous holographic lattices." Due to their technical simplicity, these configurations have received a great deal of attention in the last few years and have been shown to correctly describe momentum relaxation and hence (finite) DC conductivities. However, it is not clear whether they are able to capture other lattice effects which are of interest in condensed matter. In this paper we investigate this question focusing our attention on the phenomenon of commensurability, which arises when the lattice scale is tuned to be equal to (an integer multiple of) another momentum scale in the system. We do so by studying the formation of spatially modulated phases in various models of homogeneous holographic lattices. Our results indicate that the onset of the instability is controlled by the near horizon geometry, which for insulating solutions does carry information about the lattice. However, we observe no sharp connection between the characteristic momentum of the broken phase and the lattice pitch, which calls into question the applicability of these models to the physics of commensurability.
3D Metallic Lattices for Accelerator Applications
Shapiro, Michael A; Sirigiri, Jagadishwar R; Temkin, Richard J
2005-01-01
We present the results of research on 3D metallic lattices operating at microwave frequencies for application in (1) accelerator structures with higher order mode suppression, (2) Smith-Purcell radiation beam diagnostics, and (3) polaritonic materials for laser acceleration. Electromagnetic waves in a 3D simple cubic lattice formed by metal wires are calculated using HFSS. The bulk modes in the lattice are determined using single cell calculations with different phase advances in all three directions. The Brillouin diagram for the bulk modes is presented and indicates the absence of band gaps in simple lattices except the band below the cutoff. Lattices with thin wires as well as with thick wires have been analyzed. The Brillouin diagram also indicates the presence of low frequency 3D plasmon mode as well as the two degenerate photon modes analogous to those in a 2D lattice. Surface modes for a semi-infinite cubic lattice are modeled as a stack of cells with different phase advances in the two directions alon...
Lattice-Based Revocable Certificateless Signature
Directory of Open Access Journals (Sweden)
Ying-Hao Hung
2017-10-01
Full Text Available Certificateless signatures (CLS are noticeable because they may resolve the key escrow problem in ID-based signatures and break away the management problem regarding certificate in conventional signatures. However, the security of the mostly previous CLS schemes relies on the difficulty of solving discrete logarithm or large integer factorization problems. These two problems would be solved by quantum computers in the future so that the signature schemes based on them will also become insecure. For post-quantum cryptography, lattice-based cryptography is significant due to its efficiency and security. However, no study on addressing the revocation problem in the existing lattice-based CLS schemes is presented. In this paper, we focus on the revocation issue and present the first revocable CLS (RCLS scheme over lattices. Based on the short integer solution (SIS assumption over lattices, the proposed lattice-based RCLS scheme is shown to be existential unforgeability against adaptive chosen message attacks. By performance analysis and comparisons, the proposed lattice-based RCLS scheme is better than the previously proposed lattice-based CLS scheme, in terms of private key size, signature length and the revocation mechanism.
On Decompositions of Matrices over Distributive Lattices
Directory of Open Access Journals (Sweden)
Yizhi Chen
2014-01-01
Full Text Available Let L be a distributive lattice and Mn,q (L(Mn(L, resp. the semigroup (semiring, resp. of n × q (n × n, resp. matrices over L. In this paper, we show that if there is a subdirect embedding from distributive lattice L to the direct product ∏i=1mLi of distributive lattices L1,L2, …,Lm, then there will be a corresponding subdirect embedding from the matrix semigroup Mn,q(L (semiring Mn(L, resp. to semigroup ∏i=1mMn,q(Li (semiring ∏i=1mMn(Li, resp.. Further, it is proved that a matrix over a distributive lattice can be decomposed into the sum of matrices over some of its special subchains. This generalizes and extends the decomposition theorems of matrices over finite distributive lattices, chain semirings, fuzzy semirings, and so forth. Finally, as some applications, we present a method to calculate the indices and periods of the matrices over a distributive lattice and characterize the structures of idempotent and nilpotent matrices over it. We translate the characterizations of idempotent and nilpotent matrices over a distributive lattice into the corresponding ones of the binary Boolean cases, which also generalize the corresponding structures of idempotent and nilpotent matrices over general Boolean algebras, chain semirings, fuzzy semirings, and so forth.
Real de Asúa, D; Rodriguez Del Pozo, P; Fins, J J
2018-04-01
The development of hospital clinical ethics in Spain depends almost exclusively on the healthcare ethics committees, which have been criticized for a lack of proximity to the patient's bedside in day-to-day ethical conflicts and for their scarce practical operation, reflected in the low number of consultations they receive. In this study, we reflect on the need to change the current healthcare model in clinical ethics so as to reactivate it and call attention to the essential role of internists as the engine for this change. To this end, we propose a model in which the healthcare ethics committees incorporate ethics consultants, who are better positioned to discuss cases at the patient's bedside. We then analyse the characteristics that these consultants should have. Copyright © 2017 Elsevier España, S.L.U. and Sociedad Española de Medicina Interna (SEMI). All rights reserved.
Building a Consonance Between Religion and Science: an Antidote for the Seeming Conflict
Directory of Open Access Journals (Sweden)
Omomia O. Austin
2014-05-01
Full Text Available It is commonly argued by a school of thought that there is no relationship between religion and science. This extreme position has led to a lasting conflict, which has pitched religion against science and science against religion. The attempt in this paper is to articulate the fact that there can be an enduring consonance between religion and science. No doubt, the conflict and debate on the subject of religion and science has taken the front burner in both religious and philosophical discusses. Some scholars have argued that science has no role in religious or theological domain, while others contest that all religious concerns and considerations must be exposed to empirical investigations, and, proven by the dynamics of our intellect or reason. This paper, therefore, attempts to examine how religion and science complement each other. The author applied philosophical, sociological and historical methodology in his research. It is recommended that there is the need for dialogue between religion and science.
Coherent collisional spin dynamics in optical lattices.
Widera, Artur; Gerbier, Fabrice; Fölling, Simon; Gericke, Tatjana; Mandel, Olaf; Bloch, Immanuel
2005-11-04
We report on the observation of coherent, purely collisionally driven spin dynamics of neutral atoms in an optical lattice. For high lattice depths, atom pairs confined to the same lattice site show weakly damped Rabi-type oscillations between two-particle Zeeman states of equal magnetization, induced by spin-changing collisions. Moreover, measurement of the oscillation frequency allows for precise determination of the spin-changing collisional coupling strengths, which are directly related to fundamental scattering lengths describing interatomic collisions at ultracold temperatures.
Construction of Capacity Achieving Lattice Gaussian Codes
Alghamdi, Wael
2016-04-01
We propose a new approach to proving results regarding channel coding schemes based on construction-A lattices for the Additive White Gaussian Noise (AWGN) channel that yields new characterizations of the code construction parameters, i.e., the primes and dimensions of the codes, as functions of the block-length. The approach we take introduces an averaging argument that explicitly involves the considered parameters. This averaging argument is applied to a generalized Loeliger ensemble [1] to provide a more practical proof of the existence of AWGN-good lattices, and to characterize suitable parameters for the lattice Gaussian coding scheme proposed by Ling and Belfiore [3].
Measurement Based Quantum Computation on Fractal Lattices
Directory of Open Access Journals (Sweden)
Michal Hajdušek
2010-06-01
Full Text Available In this article we extend on work which establishes an analology between one-way quantum computation and thermodynamics to see how the former can be performed on fractal lattices. We find fractals lattices of arbitrary dimension greater than one which do all act as good resources for one-way quantum computation, and sets of fractal lattices with dimension greater than one all of which do not. The difference is put down to other topological factors such as ramification and connectivity. This work adds confidence to the analogy and highlights new features to what we require for universal resources for one-way quantum computation.
Racetrack lattices for the TRIUMF KAON factory
International Nuclear Information System (INIS)
Servranckx, R.V.; Craddock, M.K.
1989-05-01
Separated-function racetrack lattices have been developed for the KAON Factory accelerators that have more flexibility than the old circular lattices. The arcs of the large rings have a regular FODO structure with a superimposed six-fold symmetric modulation of the betafunction in order to raise γ t to infinity. In the small rings, γ t is kept high enough by choosing a sufficiently large phase advance in the arcs. Straight sections with zero dispersion are provided for rf cavities and fast injection and extraction, and with controlled dispersion for H - injection and slow extraction. The ion-optical properties of the lattices and the results from tracking studies are discussed
International Nuclear Information System (INIS)
Jansen, K.; Michael, C.; Urbach, C.
2008-04-01
We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With N f =2 flavours of light quark, this is the so-called η 2 meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the η 2 meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses. (orig.)
Continuum methods in lattice perturbation theory
International Nuclear Information System (INIS)
Becher, Thomas G
2002-01-01
We show how methods of continuum perturbation theory can be used to simplify perturbative lattice calculations. We use the technique of asymptotic expansions to expand lattice loop integrals around the continuum limit. After the expansion, all nontrivial dependence on momenta and masses is encoded in continuum loop integrals and the only genuine lattice integrals left are tadpole integrals. Using integration-by-parts relations all of these can be expressed in terms of a small number of master integrals. Four master integrals are needed for bosonic one loop integrals, sixteen in QCD with Wilson or staggered fermions
Optical lattice on an atom chip
DEFF Research Database (Denmark)
Gallego, D.; Hofferberth, S.; Schumm, Thorsten
2009-01-01
Optical dipole traps and atom chips are two very powerful tools for the quantum manipulation of neutral atoms. We demonstrate that both methods can be combined by creating an optical lattice potential on an atom chip. A red-detuned laser beam is retroreflected using the atom chip surface as a high......-quality mirror, generating a vertical array of purely optical oblate traps. We transfer thermal atoms from the chip into the lattice and observe cooling into the two-dimensional regime. Using a chip-generated Bose-Einstein condensate, we demonstrate coherent Bloch oscillations in the lattice....
Supersymmetric quiver gauge theories on the lattice
International Nuclear Information System (INIS)
Joseph, Anosh
2013-12-01
In this paper we detail the lattice constructions of several classes of supersymmetric quiver gauge theories in two and three Euclidean spacetime dimensions possessing exact supersymmetry at finite lattice spacing. Such constructions are obtained through the methods of topological twisting and geometric discretization of Euclidean Yang-Mills theories with eight and sixteen supercharges in two and three dimensions. We detail the lattice constructions of two-dimensional quiver gauge theories possessing four and eight supercharges and three-dimensional quiver gauge theories possessing eight supercharges.
Dynamical Regge calculus as lattice gravity
International Nuclear Information System (INIS)
Hagura, Hiroyuki
2001-01-01
We propose a hybrid approach to lattice quantum gravity by combining simultaneously the dynamical triangulation with the Regge calculus, called the dynamical Regge calculus (DRC). In this approach lattice diffeomorphism is realized as an exact symmetry by some hybrid (k, l) moves on the simplicial lattice. Numerical study of 3D pure gravity shows that an entropy of the DRC is not exponetially bounded if we adopt the uniform measure Π i dl i . On the other hand, using the scale-invariant measure Π i dl i /l i , we can calculate observables and observe a large hysteresis between two phases that indicates the first-order nature of the phase transition
Vortex-Peierls States in Optical Lattices
International Nuclear Information System (INIS)
Burkov, A.A.; Demler, Eugene
2006-01-01
We show that vortices, induced in cold atom superfluids in optical lattices, may order in a novel vortex-Peierls ground state. In such a state vortices do not form a simple lattice but arrange themselves in clusters, within which the vortices are partially delocalized, tunneling between classically degenerate configurations. We demonstrate that this exotic quantum many-body state is selected by an order-from-disorder mechanism for a special combination of the vortex filling and lattice geometry that has a macroscopic number of classically degenerate ground states
How to Share a Lattice Trapdoor
DEFF Research Database (Denmark)
Bendlin, Rikke; Peikert, Chris; Krehbiel, Sara
2013-01-01
We develop secure threshold protocols for two important operations in lattice cryptography, namely, generating a hard lattice Λ together with a "strong" trapdoor, and sampling from a discrete Gaussian distribution over a desired coset of Λ using the trapdoor. These are the central operations...... delegation, which is used in lattice-based hierarchical IBE schemes. Our work therefore directly transfers all these systems to the threshold setting. Our protocols provide information-theoretic (i.e., statistical) security against adaptive corruptions in the UC framework, and they are robust against up to ℓ...
Application of model search to lattice theory.
Energy Technology Data Exchange (ETDEWEB)
Rose, M.; Wilkinson, K.; Mathematics and Computer Science
2001-08-01
We have used the first-order model-searching programs MACE and SEM to study various problems in lattice theory. First, we present a case study in which the two programs are used to examine the differences between the stages along the way from lattice theory to Boolean algebra. Second, we answer several questions posed by Norman Megill and Mladen Pavicic on ortholattices and orthomodular lattices. The questions from Megill and Pavicic arose in their study of quantum logics, which are being investigated in connection with proposed computing devices based on quantum mechanics. Previous questions of a similar nature were answered by McCune and MACE in [2].
Spontaneous supersymmetry breaking on the lattice
Energy Technology Data Exchange (ETDEWEB)
Wenger, Urs [Albert Einstein Center for Fundamental Physics, Institute for Theoretical Physics, University of Bern, Sidlerstrasse 5, CH-3012 Bern (Switzerland)
2013-07-01
We discuss various strategies for regularising supersymmetric quantum field theories on a space-time lattice. In general, simulations of lattice models with spontaneously broken supersymmetry suffer from a fermion sign problem related to the vanishing of the Witten index. We discuss a novel approach which evades this problem in low dimensions by formulating the path integral on the lattice in terms of fermion loops. Then we present exact results on the spectrum and the Witten index for N=2 supersymmetric quantum mechanics and results from simulations of the spontaneously broken N=1 Wess-Zumino model.
Lattice-Like Total Perfect Codes
Directory of Open Access Journals (Sweden)
Araujo Carlos
2014-02-01
Full Text Available A contribution is made to the classification of lattice-like total perfect codes in integer lattices Λn via pairs (G, Φ formed by abelian groups G and homomorphisms Φ: Zn → G. A conjecture is posed that the cited contribution covers all possible cases. A related conjecture on the unfinished work on open problems on lattice-like perfect dominating sets in Λn with induced components that are parallel paths of length > 1 is posed as well.
Lattice-induced modulators at terahertz frequencies.
Naranjo, Guillermo A; Peralta, Xomalin G
2017-12-01
We measured the transmission spectra of an array of split-ring resonators (SRRs) up to 10 terahertz for parallel and perpendicular polarizations. Calculations of the lattice and plasmon mode dispersion relations, in combination with electromagnetic simulations, confirm the presence of multiple higher-order lattice and plasmon modes. We modify the quality factor of higher-order plasmon resonances by modulating the lattice-plasmon mode coupling via changes in the period of the array. We also propose single frequency switches and a broadband dual-state amplitude modulator based on structured illumination that actively modifies the period of the SRR array.
Group theory and lattice gauge fields
International Nuclear Information System (INIS)
Creutz, M.
1988-09-01
Lattice gauge theory, formulated in terms of invariant integrals over group elements on lattice bonds, benefits from many group theoretical notions. Gauge invariance provides an enormous symmetry and powerful constraints on expectation values. Strong coupling expansions require invariant integrals over polynomials in group elements, all of which can be evaluated by symmetry considerations. Numerical simulations involve random walks over the group. These walks automatically generate the invariant group measure, avoiding explicit parameterization. A recently proposed overrelaxation algorithm is particularly efficient at exploring the group manifold. These and other applications of group theory to lattice gauge fields are reviewed in this talk. 17 refs
Cold quarks stars from hot lattice QCD
International Nuclear Information System (INIS)
Schulze, R.; Kaempfer, B.
2010-01-01
At small net baryon densities ab initio lattice QCD provides valuable information on the finite-temperature equation of state of strongly interacting matter. Our phenomenological quasiparticle model provides a means to map such lattice results to regions relevant for future heavy-ion experiments at large baryon density; even the cool equation of state can be inferred to address the issue of quark stars. We report on (i) the side conditions (charge neutrality, beta equilibrium) in mapping latest lattice QCD results to large baryon density and (ii) scaling properties of emerging strange quark stars. (author)
Infinitesimal diffeomorfisms on the lattice
CERN. Geneva
2015-01-01
The energy-momentum tensor and local translation Ward identities constitute the essential toolkit to probe the response of a QFT to an infinitesimal change of geometry. This is relevant in a number of contexts. For instance in order to get the thermodynamical equation of state, one wants to study the response of a Euclidean QFT in a finite box to a change in the size of the box. The lattice formulation of QFTs is a prime tool to study their dynamics beyond perturbation theory. However Poincaré invariance is explicitly broken, and is supposed to be recovered only in the continuum limit. Approximate local Ward identities for translations can be defined, by they require some care for two reasons: 1) the energy-momentum tensor needs to be properly defined through a renormalization procedure; 2) the action of infinitesimal local translations (i.e. infinitesimal diffeomorfisms) is ill-defined on local observables. In this talk I will review the issues related to the renormalization of the energy-momentum tensor ...
Halo Mitigation Using Nonlinear Lattices
Sonnad, Kiran G
2005-01-01
This work shows that halos in beams with space charge effects can be controlled by combining nonlinear focusing and collimation. The study relies on Particle-in-Cell (PIC) simulations for a one dimensional, continuous focusing model. The PIC simulation results show that nonlinear focusing leads to damping of the beam oscillations thereby reducing the mismatch. It is well established that reduced mismatch leads to reduced halo formation. However, the nonlinear damping is accompanied by emittance growth causing the beam to spread in phase space. As a result, inducing nonlinear damping alone cannot help mitigate the halo. To compensate for this expansion in phase space, the beam is collimated in the simulation and further evolution of the beam shows that the halo is not regenerated. The focusing model used in the PIC is analysed using the Lie Transform perturbation theory showing that by averaging over a lattice period, one can reuduce the focusing force to a form that is identical to that used in the PIC simula...
Essentially Entropic Lattice Boltzmann Model
Atif, Mohammad; Kolluru, Praveen Kumar; Thantanapally, Chakradhar; Ansumali, Santosh
2017-12-01
The entropic lattice Boltzmann model (ELBM), a discrete space-time kinetic theory for hydrodynamics, ensures nonlinear stability via the discrete time version of the second law of thermodynamics (the H theorem). Compliance with the H theorem is numerically enforced in this methodology and involves a search for the maximal discrete path length corresponding to the zero dissipation state by iteratively solving a nonlinear equation. We demonstrate that an exact solution for the path length can be obtained by assuming a natural criterion of negative entropy change, thereby reducing the problem to solving an inequality. This inequality is solved by creating a new framework for construction of Padé approximants via quadrature on appropriate convex function. This exact solution also resolves the issue of indeterminacy in case of nonexistence of the entropic involution step. Since our formulation is devoid of complex mathematical library functions, the computational cost is drastically reduced. To illustrate this, we have simulated a model setup of flow over the NACA-0012 airfoil at a Reynolds number of 2.88 ×106.
Zhang, Geng; Sun, Di-Hua; Liu, Hui; Chen, Dong
2017-11-01
In this paper, a new lattice hydrodynamic model with consideration of the density difference of a lattice's current density and its anticipative density is proposed. The influence of lattice's self-anticipative density on traffic stability is revealed through linear stability theory and it shows that lattice's self-anticipative density can improve the stability of traffic flow. To describe the phase transition of traffic flow, the mKdV equation near the critical point is derived by using nonlinear analysis method. The propagating behavior of density wave in the unstable region can be described by the kink-antikink soliton of the mKdV equation. Numerical simulation validates the analytical results, which shows that traffic jam can be suppressed efficiently by considering lattice's self-anticipative density in the modified lattice hydrodynamic model.
Why QCD lattice theory is important to spin physicists
International Nuclear Information System (INIS)
Rebbi, C.
1982-01-01
The lattice formulation of a quantum field theory allows calculations in the regime of strong coupling, by expansion techniques, and for intermediate coupling, by Monte Carlo simulations. These computations are especially valuable in the case of Quantum Chromodynamics (QCD), where several of the most important problems are not amenable to a perturbative analysis. Monte carlo simulations, in particular, have recently emerged as a very powerful tool and have been used to evaluate a variety of important physical quantities, such as the string tension, the deconfinement temperature, the scale of the interquark potential, glueball masses and masses in the quark model spectrum. If we consider those problems of strong interactions where spin plays an important role, it is unlikely, for the moment at least, that the lattice formulation may be of relevance where the phenomena being investigated involve propagations over extended domains of space-time; thus, for instance, it is impossible to perform a meaningful simulation of a scattering experiment on the lattice. But we are at the stage where Monte Carlo calculations begin to provide relevant information on spectroscopic properties related to spin. These are briefly discussed
Link fermions in Euclidean lattice gauge theory
Energy Technology Data Exchange (ETDEWEB)
Brower, R.; Giles, R.; Maturana, G.
1984-02-15
The representation of the Wilson lattice fermion propagator as a sum over classical particle trajectories is discussed. A simple generalization of this path sum leads to an extended set of fermion theories characterized by one (or more) additional parameters. Such theories are nonlocal when written in terms of the usual four-component Dirac field. They are more naturally characterized by a local action functional whose degrees of freedom are those of a set of two-component Fermi fields defined on directed links of the lattice. Such lattice fields correspond to the direct product of a four-vector and Dirac spinor. For a suitable choice of parameters, the extended fermion theory offers a precocious approach to the continuum dispersion relation as the lattice spacing goes to zero and is therefore of interest for numerical studies of QCD.
Renormalization transformation of periodic and aperiodic lattices
International Nuclear Information System (INIS)
Macia, Enrique; Rodriguez-Oliveros, Rogelio
2006-01-01
In this work we introduce a similarity transformation acting on transfer matrices describing the propagation of elementary excitations through either periodic or Fibonacci lattices. The proposed transformation can act at two different scale lengths. At the atomic scale the transformation allows one to express the systems' global transfer matrix in terms of an equivalent on-site model one. Correlation effects among different hopping terms are described by a series of local phase factors in that case. When acting on larger scale lengths, corresponding to short segments of the original lattice, the similarity transformation can be properly regarded as describing an effective renormalization of the chain. The nature of the resulting renormalized lattice significantly depends on the kind of order (i.e., periodic or quasiperiodic) of the original lattice, expressing a delicate balance between chemical complexity and topological order as a consequence of the renormalization process
Lattice Waves, Spin Waves, and Neutron Scattering
Brockhouse, Bertram N.
1962-03-01
Use of neutron inelastic scattering to study the forces between atoms in solids is treated. One-phonon processes and lattice vibrations are discussed, and experiments that verified the existence of the quantum of lattice vibrations, the phonon, are reviewed. Dispersion curves, phonon frequencies and absorption, and models for dispersion calculations are discussed. Experiments on the crystal dynamics of metals are examined. Dispersion curves are presented and analyzed; theory of lattice dynamics is considered; effects of Fermi surfaces on dispersion curves; electron-phonon interactions, electronic structure influence on lattice vibrations, and phonon lifetimes are explored. The dispersion relation of spin waves in crystals and experiments in which dispersion curves for spin waves in Co-Fe alloy and magnons in magnetite were obtained and the reality of the magnon was demonstrated are discussed. (D.C.W)
Benchmarking computer platforms for lattice QCD applications
International Nuclear Information System (INIS)
Hasenbusch, M.; Jansen, K.; Pleiter, D.; Wegner, P.; Wettig, T.
2003-09-01
We define a benchmark suite for lattice QCD and report on benchmark results from several computer platforms. The platforms considered are apeNEXT, CRAY T3E, Hitachi SR8000, IBM p690, PC-Clusters, and QCDOC. (orig.)
Benchmarking computer platforms for lattice QCD applications
International Nuclear Information System (INIS)
Hasenbusch, M.; Jansen, K.; Pleiter, D.; Stueben, H.; Wegner, P.; Wettig, T.; Wittig, H.
2004-01-01
We define a benchmark suite for lattice QCD and report on benchmark results from several computer platforms. The platforms considered are apeNEXT, CRAY T3E; Hitachi SR8000, IBM p690, PC-Clusters, and QCDOC
Breatherlike impurity modes in discrete nonlinear lattices
DEFF Research Database (Denmark)
Hennig, D.; Rasmussen, Kim; Tsironis, G. P.
1995-01-01
We investigate the properties of a disordered generalized discrete nonlinear Schrodinger equation, containing both diagonal and nondiagonal nonlinear terms. The equation models a Linear host lattice doped with nonlinear impurities. We find different types of impurity states that form itinerant...
Arbitrary spin fermions on the lattice
International Nuclear Information System (INIS)
Bullinaria, J.A.
1985-01-01
Lattice actions are constructed for free Dirac and Majorana fermions of arbitrary (half-integer) spin various extensions of the spin 1/2 Kogut-Susskind, Kaehler and Wilson formalisms. In each case, the spectrum degeneracy and preservation of gauge invariance is analysed, and the equivalence or non-equivalence to previously constructed actions is determined. The Kogut-Susskind and lattice Kaehler actions are then written explicitly in terms of spinors to demonstrate how the degenerate fermions couple on the lattice and how the original spinorial actions are recovered (or to recovered) in the continuum limit. Both degenerate and non-degenerate mass terms are dealt with and the various U(1) invariances of the lattice actions are pointed out
n-Orthodistributivity in Orthomodular Lattices
Moes, Justin; Roddy, Micheale S.
2014-10-01
A useful generalization of distributivity in lattices n-distributivity, , was introduced in Huhn (Acta Sci. Math. 33:297-305, 1972). In Mayet and Roddy (Contrib. Gen. Algebra 5:285-294, 1987), `orthogonalized' versions, n-orthodistributivity, , of these equations were introduced and discussed. The discussion and results of Mayet and Roddy (Contrib. Gen. Algebra 5:285-294, 1987) centered on the class of modular ortholattices. In this paper we discuss and present some preliminary results for these conditions in orthomodular lattices. In particular, we completely classify the n-(ortho)distributive orthomodular lattices arising from Greechie's classical 1971 construction, and we prove that a certain simple atomless orthomodular lattice, presented in Roddy (Algebra Univers. 29:564-597, 1992), is 4-orthodistributive. It is not 3-orthodistributive.
Extended Josephson Relation and Abrikosov lattice deformation
International Nuclear Information System (INIS)
Matlock, Peter
2012-01-01
From the point of view of time-dependent Ginzburg Landau (TDGL) theory, a Josephson-like relation is derived for an Abrikosov vortex lattice accelerated and deformed by applied fields. Beginning with a review of the Josephson Relation derived from the two ingredients of a lattice-kinematics assumption in TDGL theory and gauge invariance, we extend the construction to accommodate a time-dependent applied magnetic field, a Floating-Kernel formulation of normal current, and finally lattice deformation due to the electric field and inertial effects of vortex-lattice motion. The resulting Josephson-like relation, which we call an Extended Josephson Relation, applies to a much wider set of experimental conditions than the original Josephson Relation, and is explicitly compatible with the considerations of TDGL theory.
Lattice Regenerative Cooling Methods (LRCM) Project
National Aeronautics and Space Administration — ORBITEC proposes to develop and demonstrate a novel cooling concept called Lattice Regenerative Cooling Methods (LRCM) for future high thrust in-space propulsion...
The Gluon Propagator without lattice Gribov copies on a finer lattice
Alexandrou, C; Follana, E; Forcrand, Ph. de
2002-01-01
We extend our study of the gluon propagator in quenched lattice QCD using the Laplacian gauge to a finer lattice. We verify the existence of a pole mass as we take the continuum limit and deduce a value of $\\sim 600^{+150}_{-30}$ MeV for this pole mass. We find a finite value of $(454(5){\\rm MeV})^{-2}$ for the renormalized zero-momentum propagator, in agreement with results on coarser lattices.
Reflective Writing for Medical Students on the Surgical Clerkship: Oxymoron or Antidote?
Liu, Geoffrey Z; Jawitz, Oliver K; Zheng, Daniel; Gusberg, Richard J; Kim, Anthony W
2016-01-01
Reflective writing has emerged as a solution to declining empathy during clinical training. However, the role for reflective writing has not been studied in a surgical setting. The aim of this proof-of-concept study was to assess receptivity to a reflective-writing intervention among third-year medical students on their surgical clerkship. The reflective-writing intervention was a 1-hour, peer-facilitated writing workshop. This study employed a pre-post-intervention design. Subjects were surveyed on their experience 4 weeks before participation in the intervention and immediately afterwards. Surveys assessed student receptivity to reflective writing as well as self-perceived empathy, writing habits, and communication behaviors using a Likert-response scale. Quantitative responses were analyzed using paired t tests and linear regression. Qualitative responses were analyzed using an iterative consensus model. Yale-New Haven hospital, a tertiary care academic center. All medical students of Yale School of Medicine, rotating on their surgical clerkship during a 9-month period (74 in total) were eligible. In all, 25 students completed this study. The proportion of students desiring more opportunities for reflective writing increased from 32%-64%. The proportion of students receptive to a mandatory writing workshop increased from 16%-40%. These differences were both significant (p = 0.003 and p = 0.001). In all, 88% of students also reported new insight as a result of the workshop. In total, 39% of students reported a more positive impression of the surgical profession after participation. Overall, the workshop was well-received by students and improved student attitudes toward reflective writing and the surgical profession. Larger studies are required to validate the effect of this workshop on objective empathy measures. This study demonstrates how reflective writing can be incorporated into a presurgical curriculum. Copyright © 2015 Association of Program Directors in
Distances on a lattice from noncommutative geometry
International Nuclear Information System (INIS)
Bimonte, G.; Lizzi, F.; Sparano, G.
1994-04-01
Using the tools of noncommutative geometry we calculate the distances between the points of a lattice on which the usual discretized Dirac operator has been defined. We find that these distances do not have the expected behaviour, revealing that from the metric point of view the lattice does not look at all as a set of points sitting on the continuum manifold. We thus have an additional criterion for the choice of the discretization of the Dirac operator. (author). 11 refs, 1 tab
Lattice quantum chromodynamics with approximately chiral fermions
Energy Technology Data Exchange (ETDEWEB)
Hierl, Dieter
2008-05-15
In this work we present Lattice QCD results obtained by approximately chiral fermions. We use the CI fermions in the quenched approximation to investigate the excited baryon spectrum and to search for the {theta}{sup +} pentaquark on the lattice. Furthermore we developed an algorithm for dynamical simulations using the FP action. Using FP fermions we calculate some LECs of chiral perturbation theory applying the epsilon expansion. (orig.)
Multifractal behaviour of Т-simplex lattice
Indian Academy of Sciences (India)
Sanjay Kumar, D Giri and Sujata Krishna each of the lattice points of the Цth order map by the entire Цth order map. Each of the resulting Т points is connected to one of the lines connecting the originalЦth order vertices. The fractal and spectral dimensions of this lattice are given by: = ln(Т) ln 2. (1) and. = 2 ln(Т) ln(Т + 2). (2).
Lattice quantum chromodynamics with approximately chiral fermions
International Nuclear Information System (INIS)
Hierl, Dieter
2008-05-01
In this work we present Lattice QCD results obtained by approximately chiral fermions. We use the CI fermions in the quenched approximation to investigate the excited baryon spectrum and to search for the Θ + pentaquark on the lattice. Furthermore we developed an algorithm for dynamical simulations using the FP action. Using FP fermions we calculate some LECs of chiral perturbation theory applying the epsilon expansion. (orig.)
Mining Complex Hydrobiological Data with Galois Lattices
Bertaux, Aurélie; Braud, AGNès; Ber, Florence Le
2008-01-01
International audience; We have used Galois lattices for mining hydrobiological data. These data are about macrophytes, that are macroscopic plants living in water bodies. These plants are characterized by several biological traits, that own several modalities. Our aim is to cluster the plants according to their common traits and modalities and to find out the relations between traits. Galois lattices are efficient methods for such an aim, but apply on binary data. In this article, we detail ...
Status of the Fermilab lattice supercomputer project
International Nuclear Information System (INIS)
Mackenzie, P.; Eichten, E.; Hockney, G.
1988-10-01
Fermilab has completed construction of a sixteen node (320 megaflop peak speed) parallel computer for lattice gauge theory calculations. The architecture was designed to provide the highest possible cost effectiveness while maintaining a high level of programmability and constraining as little as possible the types of lattice problems which can be done on it. The machine is programmed in C. It is a prototype for a 256 node (5 gigaflop peak speed) computer which will be assembled this winter. 6 refs
Lattice Boltzmann approach for complex nonequilibrium flows.
Montessori, A; Prestininzi, P; La Rocca, M; Succi, S
2015-10-01
We present a lattice Boltzmann realization of Grad's extended hydrodynamic approach to nonequilibrium flows. This is achieved by using higher-order isotropic lattices coupled with a higher-order regularization procedure. The method is assessed for flow across parallel plates and three-dimensional flows in porous media, showing excellent agreement of the mass flow with analytical and numerical solutions of the Boltzmann equation across the full range of Knudsen numbers, from the hydrodynamic regime to ballistic motion.
Finite size scaling and lattice gauge theory
International Nuclear Information System (INIS)
Berg, B.A.
1986-01-01
Finite size (Fisher) scaling is investigated for four dimensional SU(2) and SU(3) lattice gauge theories without quarks. It allows to disentangle violations of (asymptotic) scaling and finite volume corrections. Mass spectrum, string tension, deconfinement temperature and lattice β-function are considered. For appropriate volumes, Monte Carlo investigations seem to be able to control the finite volume continuum limit. Contact is made with Luescher's small volume expansion and possibly also with the asymptotic large volume behavior. 41 refs., 19 figs
Vague Congruences and Quotient Lattice Implication Algebras
Directory of Open Access Journals (Sweden)
Xiaoyan Qin
2014-01-01
Full Text Available The aim of this paper is to further develop the congruence theory on lattice implication algebras. Firstly, we introduce the notions of vague similarity relations based on vague relations and vague congruence relations. Secondly, the equivalent characterizations of vague congruence relations are investigated. Thirdly, the relation between the set of vague filters and the set of vague congruences is studied. Finally, we construct a new lattice implication algebra induced by a vague congruence, and the homomorphism theorem is given.
Vague Congruences and Quotient Lattice Implication Algebras
Qin, Xiaoyan; Xu, Yang
2014-01-01
The aim of this paper is to further develop the congruence theory on lattice implication algebras. Firstly, we introduce the notions of vague similarity relations based on vague relations and vague congruence relations. Secondly, the equivalent characterizations of vague congruence relations are investigated. Thirdly, the relation between the set of vague filters and the set of vague congruences is studied. Finally, we construct a new lattice implication algebra induced by a vague congruence, and the homomorphism theorem is given. PMID:25133207
Matching fields and lattice points of simplices
Loho, Georg; Smith, Ben
2018-01-01
We show that the Chow covectors of a linkage matching field define a bijection of lattice points and we demonstrate how one can recover the linkage matching field from this bijection. This resolves two open questions from Sturmfels & Zelevinsky (1993) on linkage matching fields. For this, we give an explicit construction that associates a bipartite incidence graph of an ordered partition of a common set to all lattice points in a dilated simplex. Given a triangulation of a product of two simp...
Lattice models and conformal field theories
International Nuclear Information System (INIS)
Saleur, H.
1988-01-01
Theoretical studies concerning the connection between critical physical systems and the conformal theories are reviewed. The conformal theory associated to a critical (integrable) lattice model is derived. The obtention of the central charge, critical exponents and torus partition function, using renormalization group arguments, is shown. The quantum group structure, in the integrable lattice models, and the theory of Visaro algebra representations are discussed. The relations between off-critical integrable models and conformal theories, in finite geometries, are studied
Topological Aspects of the Product of Lattices
Directory of Open Access Journals (Sweden)
Carmen Vlad
2011-01-01
Full Text Available Let be an arbitrary nonempty set and a lattice of subsets of such that ∅, X∈L. ( denotes the algebra generated by , and ( denotes those nonnegative, finite, finitely additive measures on (. In addition, ( denotes the subset of ( which consists of the nontrivial zero-one valued measures. The paper gives detailed analysis of products of lattices, their associated Wallman spaces, and products of a variety of measures.
Topological Aspects of the Product of Lattices
Vlad, Carmen
2011-01-01
Let be an arbitrary nonempty set and a lattice of subsets of such that ∅ , X ∈ L . ( ) denotes the algebra generated by , and ( ) denotes those nonnegative, finite, finitely additive measures on ( ). In addition, ( ) denotes the subset of ( ) which consists of the nontrivial zero-one valued measures. The paper gives detailed analysis of products of lattices, their associated Wallman spaces, and products of a variety of measures....
The world according to lattice QCD
International Nuclear Information System (INIS)
Sharpe, S.R.
1988-12-01
A non-technical introduction to lattice calculations is given. The successes and problems of current calculations are emphasized. A summary of lattice results on non-exotic meson and baryon masses indicates that while calculations in the quenched approximation are becoming reliable, the results differ in systematic ways from the physical values. Results for exotic mesons (glueballs and hybrids) are then presented. The future prospects are discussed. 23 refs., 4 figs
A lattice hierarchy and its continuous limits
International Nuclear Information System (INIS)
Fan Engui
2008-01-01
By introducing a discrete spectral problem, we derive a lattice hierarchy which is integrable in Liouville's sense and possesses a multi-Hamiltonian structure. It is show that the discrete spectral problem converges to the well-known AKNS spectral problem under a certain continuous limit. In particular, we construct a sequence of equations in the lattice hierarchy which approximates the AKNS hierarchy as a continuous limit
Improved lattice fermion action for heavy quarks
Cho, Yong-Gwi; Jüttner, Andreas; Kaneko, Takashi; Marinkovic, Marina; Noaki, Jun-Ichi; Tsang, Justus Tobias
2015-01-01
We develop an improved lattice action for heavy quarks based on Brillouin-type fermions, that have excellent energy-momentum dispersion relation. The leading discretization errors of $O(a)$ and $O(a^2)$ are eliminated at tree-level. We carry out a scaling study of this improved Brillouin fermion action on quenched lattices by calculating the charmonium energy-momentum dispersion relation and hyperfine splitting. We present a comparison to standard Wilson fermions and domain-wall fermions.
Lattice QCD and the Jefferson Laboratory Program
Energy Technology Data Exchange (ETDEWEB)
Jozef Dudek, Robert Edwards, David Richards, Konstantinos Orginos
2011-06-01
Lattice gauge theory provides our only means of performing \\textit{ab initio} calculations in the non-perturbative regime. It has thus become an increasing important component of the Jefferson Laboratory physics program. In this paper, we describe the contributions of lattice QCD to our understanding of hadronic and nuclear physics, focusing on the structure of hadrons, the calculation of the spectrum and properties of resonances, and finally on deriving an understanding of the QCD origin of nuclear forces.
Building the RHIC tracking lattice model
Energy Technology Data Exchange (ETDEWEB)
Luo, Y.; Fischer, W.; Tepikian, S.
2010-01-27
In this note we outline the procedure to build a realistic lattice model for the RHIC beam-beam tracking simulation. We will install multipole field errors in the arc main dipoles, arc main quadrupols and interaction region magnets (DX, D0, and triplets) and introduce a residual closed orbit, tune ripples, and physical apertures in the tracking lattice model. Nonlinearities such as local IR multipoles, second order chromaticies and third order resonance driving terms are also corrected before tracking.
Vitreous in lattice degeneration of retina.
Foos, R Y; Simons, K B
1984-05-01
A localized pocket of missing vitreous invariably overlies lattice degeneration of the retina. Subjects with lattice also have a higher rate of rhegmatogenous retinal detachment, which is usually a complication of retinal tears. The latter are in turn a result of alterations in the central vitreous--that is, synchysis senilis leading to posterior vitreous detachment. In order to determine if there is either an association or a deleterious interaction between the local and central lesions of the vitreous in eyes with lattice, a comparison was made in autopsy eyes with and without lattice the degree of synchysis and rate of vitreous detachment. Results show no association between the local and central vitreous lesions, indicating that a higher rate of vitreous detachment is not the basis for the higher rate of retinal detachment in eyes with lattice. Also, there was no suggestion of deleterious interaction between the local and central vitreous lesions, either through vitreodonesis as a basis for precocious vitreous detachment, or through a greater degree of synchysis as a basis for interconnection of local and central lacunae (which could extend the localized retinal detachment in eyes with holes in lattice degeneration).
Superfluidity of bosons on a deformable lattice
International Nuclear Information System (INIS)
Jackeli, G.; Ranninger, J.
2001-01-01
We study the superfluid properties of a system of interacting bosons on a lattice, which, moreover, are coupled to the vibrational modes of this lattice, treated here in terms of Einstein phonon modes. The ground state corresponds to two correlated condensates: that of the bosons and that of the phonons. Two competing effects determine the common collective sound-wave-like mode with sound velocity v, arising from gauge symmetry breaking. (i) The sound velocity v 0 (corresponding to a weakly interacting Bose system on a rigid lattice) in the lowest-order approximation is reduced due to reduction of the repulsive boson-boson interaction, arising from the attractive part of the phonon-mediated interaction in the static limit. (ii) The second-order correction to the sound velocity is enhanced as compared to that of bosons on a rigid lattice when the boson-phonon interaction is switched on due to the retarded nature of the phonon-mediated interaction. The overall effect is that the sound velocity is essentially unaffected by the coupling with phonons, indicating the robustness of the superfluid state. The induction of a coherent state in the phonon system driven by the condensation of the bosons could be of experimental significance, permitting spectroscopic detection of superfluid properties of bosons. Our results are based on an extension of the Beliaev-Popov formalism for a weakly interacting Bose gas on a rigid lattice to one on a deformable lattice with which it interacts
Matter-wave bright solitons in effective bichromatic lattice potentials
Indian Academy of Sciences (India)
Matter-wave bright solitons in bichromatic lattice potentials are considered and their dynamics for different lattice environments are studied. Bichromatic potentials are created from superpositions of (i) two linear optical lattices and (ii) a linear and a nonlinear optical lattice. Effective potentials are found for the solitons in both ...
An approach to the isoperimetric problem on some lattices
International Nuclear Information System (INIS)
Duarte, J.A.M.S.
1979-01-01
In this paper it is shown how elements of convex-set theory and lattice symmetry requirements can be combined to determine the areas, symmetry point groups and lattice constants of all isoperimetric solutions for regular lattices. The technique is also applied to one semi-regular lattice, where it assists in obtaining the exact expansion for polygonal closures. (author)
Hyper-lattice algebraic model for data warehousing
Sen, Soumya; Chaki, Nabendu
2016-01-01
This book presents Hyper-lattice, a new algebraic model for partially ordered sets, and an alternative to lattice. The authors analyze some of the shortcomings of conventional lattice structure and propose a novel algebraic structure in the form of Hyper-lattice to overcome problems with lattice. They establish how Hyper-lattice supports dynamic insertion of elements in a partial order set with a partial hierarchy between the set members. The authors present the characteristics and the different properties, showing how propositions and lemmas formalize Hyper-lattice as a new algebraic structure.
An extended lattice model accounting for traffic jerk
Redhu, Poonam; Siwach, Vikash
2018-02-01
In this paper, a flux difference lattice hydrodynamics model is extended by considering the traffic jerk effect which comes due to vehicular motion of non-motor automobiles. The effect of traffic jerk has been examined through linear stability analysis and shown that it can significantly enlarge the unstable region on the phase diagram. To describe the phase transition of traffic flow, mKdV equation near the critical point is derived through nonlinear stability analysis. The theoretical findings have been verified using numerical simulation which confirms that the jerk parameter plays an important role in stabilizing the traffic jam efficiently in sensing the flux difference of leading sites.
Lattice Gauge Theory and the Origin of Mass
Energy Technology Data Exchange (ETDEWEB)
Kronfeld, Andreas S.
2013-08-01
Most of the mass of everyday objects resides in atomic nuclei/ the total of the electrons' mass adds up to less than one part in a thousand. The nuclei are composed of nucleons---protons and neutrons---whose nuclear binding energy, though tremendous on a human scale, is small compared to their rest energy. The nucleons are, in turn, composites of massless gluons and nearly massless quarks. It is the energy of these confined objects, via $M=E/c^2$, that is responsible for everyday mass. This article discusses the physics of this mechanism and the role of lattice gauge theory in establishing its connection to quantum chromodynamics.
Few quantum particles on one dimensional lattices
Energy Technology Data Exchange (ETDEWEB)
Valiente Cifuentes, Manuel
2010-06-18
There is currently a great interest in the physics of degenerate quantum gases and low-energy few-body scattering due to the recent experimental advances in manipulation of ultracold atoms by light. In particular, almost perfect periodic potentials, called optical lattices, can be generated. The lattice spacing is fixed by the wavelength of the laser field employed and the angle betwen the pair of laser beams; the lattice depth, defining the magnitude of the different band gaps, is tunable within a large interval of values. This flexibility permits the exploration of different regimes, ranging from the ''free-electron'' picture, modified by the effective mass for shallow optical lattices, to the tight-binding regime of a very deep periodic potential. In the latter case, effective single-band theories, widely used in condensed matter physics, can be implemented with unprecedent accuracy. The tunability of the lattice depth is nowadays complemented by the use of magnetic Feshbach resonances which, at very low temperatures, can vary the relevant atom-atom scattering properties at will. Moreover, optical lattices loaded with gases of effectively reduced dimensionality are experimentally accessible. This is especially important for one spatial dimension, since most of the exactly solvable models in many-body quantum mechanics deal with particles on a line; therefore, experiments with one-dimensional gases serve as a testing ground for many old and new theories which were regarded as purely academic not so long ago. The physics of few quantum particles on a one-dimensional lattice is the topic of this thesis. Most of the results are obtained in the tight-binding approximation, which is amenable to exact numerical or analytical treatment. For the two-body problem, theoretical methods for calculating the stationary scattering and bound states are developed. These are used to obtain, in closed form, the two-particle solutions of both the Hubbard and
Few quantum particles on one dimensional lattices
International Nuclear Information System (INIS)
Valiente Cifuentes, Manuel
2010-01-01
There is currently a great interest in the physics of degenerate quantum gases and low-energy few-body scattering due to the recent experimental advances in manipulation of ultracold atoms by light. In particular, almost perfect periodic potentials, called optical lattices, can be generated. The lattice spacing is fixed by the wavelength of the laser field employed and the angle betwen the pair of laser beams; the lattice depth, defining the magnitude of the different band gaps, is tunable within a large interval of values. This flexibility permits the exploration of different regimes, ranging from the ''free-electron'' picture, modified by the effective mass for shallow optical lattices, to the tight-binding regime of a very deep periodic potential. In the latter case, effective single-band theories, widely used in condensed matter physics, can be implemented with unprecedent accuracy. The tunability of the lattice depth is nowadays complemented by the use of magnetic Feshbach resonances which, at very low temperatures, can vary the relevant atom-atom scattering properties at will. Moreover, optical lattices loaded with gases of effectively reduced dimensionality are experimentally accessible. This is especially important for one spatial dimension, since most of the exactly solvable models in many-body quantum mechanics deal with particles on a line; therefore, experiments with one-dimensional gases serve as a testing ground for many old and new theories which were regarded as purely academic not so long ago. The physics of few quantum particles on a one-dimensional lattice is the topic of this thesis. Most of the results are obtained in the tight-binding approximation, which is amenable to exact numerical or analytical treatment. For the two-body problem, theoretical methods for calculating the stationary scattering and bound states are developed. These are used to obtain, in closed form, the two-particle solutions of both the Hubbard and extended Hubbard models
SSC lattice database and graphical interface
International Nuclear Information System (INIS)
Trahern, C.G.; Zhou, J.
1991-11-01
When completed the Superconducting Super Collider will be the world's largest accelerator complex. In order to build this system on schedule, the use of database technologies will be essential. In this paper we discuss one of the database efforts underway at the SSC, the lattice database. The SSC lattice database provides a centralized source for the design of each major component of the accelerator complex. This includes the two collider rings, the High Energy Booster, Medium Energy Booster, Low Energy Booster, and the LINAC as well as transfer and test beam lines. These designs have been created using a menagerie of programs such as SYNCH, DIMAD, MAD, TRANSPORT, MAGIC, TRACE3D AND TEAPOT. However, once a design has been completed, it is entered into a uniform database schema in the database system. In this paper we discuss the reasons for creating the lattice database and its implementation via the commercial database system SYBASE. Each lattice in the lattice database is composed of a set of tables whose data structure can describe any of the SSC accelerator lattices. In order to allow the user community access to the databases, a programmatic interface known as dbsf (for database to several formats) has been written. Dbsf creates ascii input files appropriate to the above mentioned accelerator design programs. In addition it has a binary dataset output using the Self Describing Standard data discipline provided with the Integrated Scientific Tool Kit software tools. Finally we discuss the graphical interfaces to the lattice database. The primary interface, known as OZ, is a simulation environment as well as a database browser
Elcoro, Luis; Etxebarria, Jesus
2011-01-01
The requirement of rotational invariance for lattice potential energies is investigated. Starting from this condition, it is shown that the Cauchy relations for the elastic constants are fulfilled if the lattice potential is built from pair interactions or when the first-neighbour approximation is adopted. This is seldom recognized in widely used…
Topological phases of shaken quantum Ising lattices
International Nuclear Information System (INIS)
Fernández-Lorenzo, Samuel; Porras, Diego; García-Ripoll, Juan José
2016-01-01
The quantum compass model consists of a two-dimensional square spin lattice where the orientation of the spin–spin interactions depends on the spatial direction of the bonds. It has remarkable symmetry properties and the ground state shows topological degeneracy. The implementation of the quantum compass model in quantum simulation setups like ultracold atoms and trapped ions is far from trivial, since spin interactions in those systems typically are independent of the spatial direction. Ising spin interactions, on the contrary, can be induced and controlled in atomic setups with state-of-the art experimental techniques. In this work, we show how the quantum compass model on a rectangular lattice can be simulated by the use of the photon-assisted tunneling induced by periodic drivings on a quantum Ising spin model. We describe a procedure to adiabatically prepare one of the doubly degenerate ground states of this model by adiabatically ramping down a transverse magnetic field, with surprising differences depending on the parity of the lattice size. Exact diagonalizations confirm the validity of this approach for small lattices. Specific implementations of this scheme are presented with ultracold atoms in optical lattices in the Mott insulator regime, as well as with Rydberg atoms. (paper)
Lattice mismatch modeling of aluminum alloys
Energy Technology Data Exchange (ETDEWEB)
Shin, Dongwon; Roy, Shibayan; Watkins, Thomas R.; Shyam, Amit
2017-10-01
We present a theoretical framework to accurately predict the lattice mismatch between the fcc matrix and precipitates in the multi-component aluminum alloys as a function of temperature and composition. We use a computational thermodynamic approach to model the lattice parameters of the multi-component fcc solid solution and θ'-Al2Cu precipitate phase. Better agreement between the predicted lattice parameters of fcc aluminum in five commercial alloys (206, 319, 356, A356, and A356 + 0.5Cu) and experimental data from the synchrotron X-ray diffraction (SXD) has been obtained when simulating supersaturated rather than equilibrium solid solutions. We use the thermal expansion coefficient of thermodynamically stable θ-Al2Cu to describe temperature-dependent lattice parameters of meta-stable θ' and to show good agreement with the SXD data. Both coherent and semi-coherent interface mismatches between the fcc aluminum matrix and θ' in Al-Cu alloys are presented as a function of temperature. Our calculation results show that the concentration of solute atoms, particularly Cu, in the matrix greatly affects the lattice mismatch
Techniques for transparent lattice measurement and correction
Cheng, Weixing; Li, Yongjun; Ha, Kiman
2017-07-01
A novel method has been successfully demonstrated at NSLS-II to characterize the lattice parameters with gated BPM turn-by-turn (TbT) capability. This method can be used at high current operation. Conventional lattice characterization and tuning are carried out at low current in dedicated machine studies which include beam-based measurement/correction of orbit, tune, dispersion, beta-beat, phase advance, coupling etc. At the NSLS-II storage ring, we observed lattice drifting during beam accumulation in user operation. Coupling and lifetime change while insertion device (ID) gaps are moved. With the new method, dynamical lattice correction is possible to achieve reliable and productive operations. A bunch-by-bunch feedback system excites a small fraction (∼1%) of bunches and gated BPMs are aligned to see those bunch motions. The gated TbT position data are used to characterize the lattice hence correction can be applied. As there are ∼1% of total charges disturbed for a short period of time (several ms), this method is transparent to general user operation. We demonstrated the effectiveness of these tools during high current user operation.
Full CKM matrix with lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Okamoto, Masataka; /Fermilab
2004-12-01
The authors show that it is now possible to fully determine the CKM matrix, for the first time, using lattice QCD. |V{sub cd}|, |V{sub cs}|, |V{sub ub}|, |V{sub cb}| and |V{sub us}| are, respectively, directly determined with the lattice results for form factors of semileptonic D {yields} {pi}lv, D {yields} Klv, B {yields} {pi}lv, B {yields} Dlv and K {yields} {pi}lv decays. The error from the quenched approximation is removed by using the MILC unquenced lattice gauge configurations, where the effect of u, d and s quarks is included. The error from the ''chiral'' extrapolation (m{sub l} {yields} m{sub ud}) is greatly reduced by using improved staggered quarks. The accuracy is comparable to that of the Particle Data Group averages. In addition, |V{sub ud}|, |V{sub ts}|, |V{sub ts}| and |V{sub td}| are determined by using unitarity of the CKM matrix and the experimental result for sin (2{beta}). In this way, they obtain all 9 CKM matrix elements, where the only theoretical input is lattice QCD. They also obtain all the Wolfenstein parameters, for the first time, using lattice QCD.
Classification of lattices: a new step
International Nuclear Information System (INIS)
Gruber, B.
1997-01-01
From the classification of (three-dimensional) lattices into the 14 Bravais types, the finer classifications into the 44 Niggli characters and 24 Delaunay sorts are considered. The last two divisions are mutually incompatible and the Niggli characters show a disturbing 'asymmetry' with respect to the conventional parameters. The aim of the paper is to find a common subdivision of both the Niggli characters and Delaunay sorts that reveals no 'asymmetry' and is crystallographically meaningful. The first attempt based on separating the non-sharp inequalities (≤) into sharp inequalities ( 5 , its Buerger points. These Buerger points lie in two convex five-dimensional hyperpolyhedra Ω + , Ω - . The division of lattices into classes is determined by the distribution of their Buerger points along the vertices, edges, faces, three- and four-dimensional hyperfaces and the interior of Ω + and Ω - . The resulting classes are called genera. There are 127 of them. They form a subdivision of both the Delaunay sorts and the Niggli characters (and, consequently, also of the Bravais types) and their parameter ranges are open. Genera stand for a remarkably strong bond between lattices. The lattices belonging to the same genus agree in a series of important crystallographic properties. Genera are explicitly described by systems of linear inequalities. The five-dimensional geometrical objects obtained in this way are illustrated by their three-dimensional cross sections. From these illustrations, a suitable notation of the genera was derived. Extensive tables enable the determination of the genus of a given lattice. (orig.)
Incommensurate lattice modulations in Potassium Vanadate
Chakoumakos, Bryan; Banerjee, Arnab; Mark, Lumsden; Cao, Huibo; Kim, Jong-Woo; Hoffman, Christina; Wang, Xiaoping
Potassium Vanadate (K2V3O8) is an S = 1/2 2D square lattice antiferromagnet that shows spin reorientation indicating a strong coupling between the magnetism and its dielectric properties with a promise of rich physics that promises multiferroicity. These tangible physical properties are strongly tied through a spin-lattice coupling to the underlying lattice and superlattice behavior. It has a superlattice (SL) onsetting below Tc = 115 K with an approximate [3 x 3 x 2] modulation. Here we present our recent experiments at TOPAZ beamline at SNS which for the first time proves conclusively that the lattice modulations are incommensurate, with an in-plane Q of 0.315. We will also show our attempts to refine the data using JANA which requires a redefinition of the lattice, as well as the temperature and Q dependence of the superlattice modulation measured using neutrons at HFIR and synchrotron x-rays at APS. Our results are not only relevant for the ongoing search of multifunctional behavior in K2V3O8 but also generally for the superlattice modulations observed in a large family of fresnoites. Work performed at ORNL and ANL is supported by U.S. Dept. of Energy, Office of Basic Energy Sciences and Office of User Facilities Division.
The thermoelectric properties of inhomogeneous holographic lattices
Energy Technology Data Exchange (ETDEWEB)
Donos, Aristomenis [DAMTP, University of Cambridge,Wilberforce Road, Cambridge, CB3 0WA (United Kingdom); Gauntlett, Jerome P. [Blackett Laboratory, Imperial College,Prince Consort Rd, London, SW7 2AZ (United Kingdom)
2015-01-09
We consider inhomogeneous, periodic, holographic lattices of D=4 Einstein-Maxwell theory. We show that the DC thermoelectric conductivity matrix can be expressed analytically in terms of the horizon data of the corresponding black hole solution. We numerically construct such black hole solutions for lattices consisting of one, two and ten wave-numbers. We numerically determine the AC electric conductivity which reveals Drude physics as well as resonances associated with sound modes. No evidence for an intermediate frequency scaling regime is found. All of the monochromatic lattice black holes that we have constructed exhibit scaling behaviour at low temperatures which is consistent with the appearance of AdS{sub 2}×ℝ{sup 2} in the far IR at T=0.
Updated lattice results for parton distributions
Energy Technology Data Exchange (ETDEWEB)
Alexandrou, Constantia [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; The Cyprus Institute, Nicosia (Cyprus); Cichy, Krzysztof [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik; Poznan Univ. (Poland). Faculty of Physics; Constantinou, Martha [Temple Univ., Philadelphia, PA (United States); Hadjiyiannakou, Kyriakos [Cyprus Univ., Nicosia (Cyprus). Dept. of Physics; Jansen, Karl; Steffens, Fernanda; Wiese, Christian [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC
2017-07-15
We provide an analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The x-dependence of the calculated PDFs resembles the one of the phenomenological parameterizations, a feature that makes this approach very promising. Furthermore, we apply momentum smearing for the relevant matrix elements to compute the lattice PDFs and find a large improvement factor when compared to conventional Gaussian smearing. This allows us to extend the lattice computation of the distributions to higher values of the nucleon momentum, which is essential for the prospects of a reliable extraction of the PDFs in the future.
Chiral perturbation theory for lattice QCD
Energy Technology Data Exchange (ETDEWEB)
Baer, Oliver
2010-07-21
The formulation of chiral perturbation theory (ChPT) for lattice Quantum Chromodynamics (QCD) is reviewed. We start with brief summaries of ChPT for continuum QCD as well as the Symanzik effective theory for lattice QCD. We then review the formulation of ChPT for lattice QCD. After an additional chapter on partial quenching and mixed action theories various concrete applications are discussed: Wilson ChPT, staggered ChPT and Wilson ChPT with a twisted mass term. The remaining chapters deal with the epsilon regime with Wilson fermions and selected results in mixed action ChPT. Finally, the formulation of heavy vector meson ChPT with Wilson fermions is discussed. (orig.)
Periodic Toda lattice in quantum mechanics
International Nuclear Information System (INIS)
Matsuyama, A.
1992-01-01
The quantum mechanical periodic Toda lattice is studied by the direct diagonalization of the Hamiltonian. The eigenstates are classified according to the irreducible representations of the dihedral group D N . It is shown that Gutzwiller's quantization conditions are satisfied and they have a one-to-one correspondence to the irreducible representation of the D N group. The authors have also carried out the semiclassical quantization of the periodic Toda lattice by the EBK formulation. The eigenvalues of the semiclassical quantization have a one-to-one correspondence to the integer quantum numbers, and those quantum numbers also have a close relationship to the symmetry of the state. Numerical calculations have been done for N = 3, 4, 5, and 6 particle periodic Toda lattices. The distributions of the eigenvalues are systematic and distinguished by the symmetry of the state. As illustrative examples, amplitudes of the wave functions and density distributions are shown. 14 refs., 8 figs., 11 tabs
Exotic meson decay widths using lattice QCD
International Nuclear Information System (INIS)
Cook, M. S.; Fiebig, H. R.
2006-01-01
A decay width calculation for a hybrid exotic meson h, with J PC =1 -+ , is presented for the channel h→πa 1 . This quenched lattice QCD simulation employs Luescher's finite box method. Operators coupling to the h and πa 1 states are used at various levels of smearing and fuzzing, and at four quark masses. Eigenvalues of the corresponding correlation matrices yield energy spectra that determine scattering phase shifts for a discrete set of relative πa 1 momenta. Although the phase shift data is sparse, fits to a Breit-Wigner model are attempted, resulting in a decay width of about 60 MeV when averaged over two lattice sizes having a lattice spacing of 0.07 fm
Making sense of nanocrystal lattice fringes
International Nuclear Information System (INIS)
Fraundorf, P.; Qin Wentao; Moeck, Peter; Mandell, Eric
2005-01-01
The orientation dependence of thin-crystal lattice fringes can be gracefully quantified using fringe-visibility maps, a direct-space analog of Kikuchi maps [Nishikawa and Kikuchi, Nature (London) 121, 1019 (1928)]. As in navigation of reciprocal space with the aid of Kikuchi lines, fringe-visibility maps facilitate acquisition of crystallographic information from lattice images. In particular, these maps can help researchers to determine the three-dimensional lattice of individual nanocrystals, to 'fringe-fingerprint' collections of randomly oriented particles, and to measure local specimen thickness with only a modest tilt. Since the number of fringes in an image increases with maximum spatial-frequency squared, these strategies (with help from more precise goniometers) will be more useful as aberration correction moves resolutions into the subangstrom range
Updated lattice results for parton distributions
International Nuclear Information System (INIS)
Alexandrou, Constantia; Cichy, Krzysztof; Hadjiyiannakou, Kyriakos; Jansen, Karl; Steffens, Fernanda; Wiese, Christian
2017-07-01
We provide an analysis of the x-dependence of the bare unpolarized, helicity and transversity iso-vector parton distribution functions (PDFs) from lattice calculations employing (maximally) twisted mass fermions. The x-dependence of the calculated PDFs resembles the one of the phenomenological parameterizations, a feature that makes this approach very promising. Furthermore, we apply momentum smearing for the relevant matrix elements to compute the lattice PDFs and find a large improvement factor when compared to conventional Gaussian smearing. This allows us to extend the lattice computation of the distributions to higher values of the nucleon momentum, which is essential for the prospects of a reliable extraction of the PDFs in the future.
Critical Power Performance of Tight Lattice Bundle
Yamamoto, Yasushi; Hiraiwa, Kouji; Morooka, Shinichi; Abe, Nobuaki
An innovative fuel cycle system concept named BARS (BWR with an Advanced Recycle System) has been proposed as a future fuel cycle option aiming at enhanced utilization of uranium resources and reduction of radioactive wastes. In BARS, the spent fuel from conventional light water reactors (LWRs) is recycled as a mixed oxide (MOX) fuel for a BWR core with the fast neutron spectrum by means of oxide dry-processing and vibro-packing fuel fabrication. The fast neutron spectrum is obtained by means of triangular tight fuel lattice. Further study on BARS, especially on tight lattice MOX fuel, has been initiated as a joint study by Toshiba and Gifu University. The objective of this paper is to show the latest progress of the study on BARS, especially concerning the thermal-hydraulics measurements for tight lattice bundle.
Lattice Boltzmann model for numerical relativity.
Ilseven, E; Mendoza, M
2016-02-01
In the Z4 formulation, Einstein equations are written as a set of flux conservative first-order hyperbolic equations that resemble fluid dynamics equations. Based on this formulation, we construct a lattice Boltzmann model for numerical relativity and validate it with well-established tests, also known as "apples with apples." Furthermore, we find that by increasing the relaxation time, we gain stability at the cost of losing accuracy, and by decreasing the lattice spacings while keeping a constant numerical diffusivity, the accuracy and stability of our simulations improve. Finally, in order to show the potential of our approach, a linear scaling law for parallelization with respect to number of CPU cores is demonstrated. Our model represents the first step in using lattice kinetic theory to solve gravitational problems.
Lattice models for invasions through patchy environments.
Campos, Daniel; Méndez, Vicenç; Ortega-Cejas, Vicente
2008-10-01
We analyze traveling front solutions for a class of reaction-transport Lattice Models (LMs) in order to claim their interest on the description of biological invasions. As lattice models are spatially discrete models, we address here the problem of invasions trough patchy habitats, where every node in the lattice represents a different patch. Distributed generation times for the individuals are considered, so that different temporal patterns can be studied. Specifically, we explore some examples of seasonal and nonseasonal patterns which may be of ecological interest. The main advantage of the LMs described here is that a direct correspondence between these discrete models and a mesoscopic description of Continuous-Time Random Walks (CTRW) can be found. This point is of great importance, since many times one needs analytical expressions to support or validate numerical results, or vice versa. Finally, that correspondence allows us to provide a discussion about some general aspects of reaction-dispersal models.
Fractional quantum Hall effect in optical lattices
International Nuclear Information System (INIS)
Hafezi, M.; Demler, E.; Lukin, M. D.; Soerensen, A. S.
2007-01-01
We analyze a recently proposed method to create fractional quantum Hall (FQH) states of atoms confined in optical lattices [A. Soerensen et al., Phys. Rev. Lett. 94, 086803 (2005)]. Extending the previous work, we investigate conditions under which the FQH effect can be achieved for bosons on a lattice with an effective magnetic field and finite on-site interaction. Furthermore, we characterize the ground state in such systems by calculating Chern numbers which can provide direct signatures of topological order and explore regimes where the characterization in terms of wave-function overlap fails. We also discuss various issues which are relevant for the practical realization of such FQH states with ultracold atoms in an optical lattice, including the presence of a long-range dipole interaction which can improve the energy gap and stabilize the ground state. We also investigate a detection technique based on Bragg spectroscopy to probe these systems in an experimental realization
Directory of Open Access Journals (Sweden)
Patrick Durel
2006-06-01
Full Text Available Cette étude examine les opérations mentales d'apprenants utilisant l'assistant grammatical Antidote en phase de révision de leurs productions écrites. Analysant des données obtenues à partir de la méthode des protocoles verbaux, ce travail montre comment ce type d'activité de révision assistée par ordinateur conduit l'apprenant à manipuler, construire, renforcer ou élargir le champ d'application de ses connaissances, qu'elles soient déclaratives ou procédurales. Les éléments dégagés indiquent que l'utilisation d'Antidote peut être vecteur d'apprentissage et offrent quelques pistes permettant de concevoir des activités de révision assistée par ordinateur qui s'inscrivent dans le cadre d'une didactique de la production scripturale.This study explores learners' cognitive processes when using the grammar assistant software Antidote during the revision phase of their composition. Analysing data obtained using a hybrid form of verbal protocols, it shows how computer-assisted revision activity can lead learners to manipulate, build or reinforce declarative and procedural knowledge. We argue that using grammar assistant software can be conducive to learning. The results of the analysis provide an insight into how such a tool can be integrated into classroom activities, contributing to writing quality and the acquisition of revision strategies.
Fast lattice Boltzmann solver for relativistic hydrodynamics.
Mendoza, M; Boghosian, B M; Herrmann, H J; Succi, S
2010-07-02
A lattice Boltzmann formulation for relativistic fluids is presented and numerically validated through quantitative comparison with recent hydrodynamic simulations of relativistic fluids. In order to illustrate its capability to handle complex geometries, the scheme is also applied to the case of a three-dimensional relativistic shock wave, generated by a supernova explosion, impacting on a massive interstellar cloud. This formulation opens up the possibility of exporting the proven advantages of lattice Boltzmann methods, namely, computational efficiency and easy handling of complex geometries, to the context of (mildly) relativistic fluid dynamics at large, from quark-gluon plasmas up to supernovae with relativistic outflows.
Automated generation of lattice QCD Feynman rules
International Nuclear Information System (INIS)
Hart, A.; Mueller, E.H.; Horgan, R.R.
2009-04-01
The derivation of the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially for highly improved actions such as HISQ. This task is, however, both important and particularly suitable for automation. We describe a suite of software to generate and evaluate Feynman rules for a wide range of lattice field theories with gluons and (relativistic and/or heavy) quarks. Our programs are capable of dealing with actions as complicated as (m)NRQCD and HISQ. Automated differentiation methods are used to calculate also the derivatives of Feynman diagrams. (orig.)
Response of Kondo lattice systems to pressure
International Nuclear Information System (INIS)
Thompson, J.D.; Borges, H.A.; Fisk, Z.; Horn, S.; Parks, R.D.; Wells, G.L.
1987-01-01
Yb-based Kondo lattice systems (YbAgCu 4 , YbCu 2 Si 2 , YbRh 2 Si 2 ) represent an interesting class of materials in which it is possible to study systematically the development of heavy electron behavior through the application of pressure. Certainly, additional experiments are required to determine to what extent Yb compounds are mirror images of their Ce counterparts. Finally, pressure reveals the presence of competing interactions for which a simple model exists that qualitatively accounts for the pressure response observed in a large number of Ce, U and Yb-based Kondo lattice systems
Neutron Electric Dipole Moment on the Lattice
Directory of Open Access Journals (Sweden)
Yoon Boram
2018-01-01
Full Text Available For the neutron to have an electric dipole moment (EDM, the theory of nature must have T, or equivalently CP, violation. Neutron EDM is a very good probe of novel CP violation in beyond the standard model physics. To leverage the connection between measured neutron EDM and novel mechanism of CP violation, one requires the calculation of matrix elements for CP violating operators, for which lattice QCD provides a first principle method. In this paper, we review the status of recent lattice QCD calculations of the contributions of the QCD Θ-term, the quark EDM term, and the quark chromo-EDM term to the neutron EDM.
Neutron Electric Dipole Moment on the Lattice
Yoon, Boram; Bhattacharya, Tanmoy; Gupta, Rajan
2018-03-01
For the neutron to have an electric dipole moment (EDM), the theory of nature must have T, or equivalently CP, violation. Neutron EDM is a very good probe of novel CP violation in beyond the standard model physics. To leverage the connection between measured neutron EDM and novel mechanism of CP violation, one requires the calculation of matrix elements for CP violating operators, for which lattice QCD provides a first principle method. In this paper, we review the status of recent lattice QCD calculations of the contributions of the QCD Θ-term, the quark EDM term, and the quark chromo-EDM term to the neutron EDM.
Two Dimensional Super QCD on a Lattice
Energy Technology Data Exchange (ETDEWEB)
Catterall, Simon [Syracuse U.; Veernala, Aarti [Fermilab
2017-10-04
We construct a lattice theory with one exact supersymmetry which consists of fields transforming in both the adjoint and fundamental representations of a U(Nc) gauge group. In addition to gluons and gluinos, the theory contains Nf flavors of fermion in the fundamental representation along with their scalar partners and is invariant under a global U(Nf) flavor symmetry. The lattice action contains an additional Fayet-Iliopoulos term which can be used to generate a scalar potential. We perform numerical simulations that corroborate the theoretical expectation that supersymmetry is spontaneously broken for Nf
Automated generation of lattice QCD Feynman rules
Energy Technology Data Exchange (ETDEWEB)
Hart, A.; Mueller, E.H. [Edinburgh Univ. (United Kingdom). SUPA School of Physics and Astronomy; von Hippel, G.M. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Horgan, R.R. [Cambridge Univ. (United Kingdom). DAMTP, CMS
2009-04-15
The derivation of the Feynman rules for lattice perturbation theory from actions and operators is complicated, especially for highly improved actions such as HISQ. This task is, however, both important and particularly suitable for automation. We describe a suite of software to generate and evaluate Feynman rules for a wide range of lattice field theories with gluons and (relativistic and/or heavy) quarks. Our programs are capable of dealing with actions as complicated as (m)NRQCD and HISQ. Automated differentiation methods are used to calculate also the derivatives of Feynman diagrams. (orig.)
Late complications following cryotherapy of lattice degeneration.
Benson, W E; Morse, P H; Nantawan, P
1977-10-01
We observed 341 patients who had received cryotherapy for lattice degeneration in order to identify possible late complications. Sequelae such as retinal tears posterior to an operculum or flap tears within treated areas showed that treatment did not necessarily prevent subsequent vitreous traction. Moreover, the newly created flap tears may extend beyond the treated area and can cause retinal detachment. Even scleral buckling did not necesserily prevent further traction. Therefore, we concluded that when cryotherapy is used to treat lattice degeneration, an adequate margin of surrounding retina should be treated and the treatment should extend to the ora serrata.
Genetics of lattice degeneration of the retina.
Murakami, F; Ohba, N
1982-01-01
First-degree relatives of proband patients with lattice degeneration of the retina revealed a significantly higher prevalence of the disease than the prevalence in the general population: the former had the disease about three times as frequently as the latter. The observed data were analyzed in terms of their accordance with recognized genetic models. The inheritance pattern did not fit well to a monogenic mode of inheritance, and it was hypothesized that a polygenic or multifactorial mode of inheritance is the most likely for lattice degeneration of the retina.
Deflation acceleration of lattice QCD simulations
International Nuclear Information System (INIS)
Luescher, Martin
2007-01-01
Close to the chiral limit, many calculations in numerical lattice QCD can potentially be accelerated using low-mode deflation techniques. In this paper it is shown that the recently introduced domain-decomposed deflation subspaces can be propagated along the field trajectories generated by the Hybrid Monte Carlo (HMC) algorithm with a modest effort. The quark forces that drive the simulation may then be computed using a deflation-accelerated solver for the lattice Dirac equation. As a consequence, the computer time required for the simulations is significantly reduced and an improved scaling behaviour of the simulation algorithm with respect to the quark mass is achieved
Deflation acceleration of lattice QCD simulations
Lüscher, Martin
2007-01-01
Close to the chiral limit, many calculations in numerical lattice QCD can potentially be accelerated using low-mode deflation techniques. In this paper it is shown that the recently introduced domain-decomposed deflation subspaces can be propagated along the field trajectories generated by the Hybrid Monte Carlo (HMC) algorithm with a modest effort. The quark forces that drive the simulation may then be computed using a deflation-accelerated solver for the lattice Dirac equation. As a consequence, the computer time required for the simulations is significantly reduced and an improved scaling behaviour of the simulation algorithm with respect to the quark mass is achieved.
YANG-MILLS FIELDS AND THE LATTICE.
Energy Technology Data Exchange (ETDEWEB)
CREUTZ,M.
2004-05-18
The Yang-Mills theory lies at the heart of our understanding of elementary particle interactions. For the strong nuclear forces, we must understand this theory in the strong coupling regime. The primary technique for this is the lattice. While basically an ultraviolet regulator, the lattice avoids the use of a perturbative expansion. I discuss some of the historical circumstances that drove us to this approach, which has had immense success, convincingly demonstrating quark confinement and obtaining crucial properties of the strong interactions from first principles.
Mobile localization in nonlinear Schroedinger lattices
Energy Technology Data Exchange (ETDEWEB)
Gomez-Gardenes, J. [Departamento de Fisica de la Materia Condensada and Instituto de Biocomputacion y Fisica de los Sistemas Complejos (BIFI), Universidad de Zaragoza, 50009 Zaragoza (Spain) and Departamento de Teoria y Simulacion de Sistemas Complejos, Instituto de Ciencia de Materiales de Aragon (ICMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain)]. E-mail: gardenes@unizar.es; Falo, F. [Departamento de Fisica de la Materia Condensada and Instituto de Biocomputacion y Fisica de los Sistemas Complejos (BIFI), Universidad de Zaragoza, 50009 Zaragoza (Spain); Departamento de Teoria y Simulacion de Sistemas Complejos, Instituto de Ciencia de Materiales de Aragon (ICMA), CSIC-Universidad de Zaragoza, 50009 Zaragoza (Spain); Floria, L.M. [Departamento de Fisica de la Materia Condensada and Instituto de Biocomputacion y Fisica de los Sistemas Complejos (BIFI), Universidad de Zaragoza, 50009 Zaragoza (Spain)
2004-11-15
Using continuation methods from the integrable Ablowitz-Ladik lattice, we have studied the structure of numerically exact mobile discrete breathers in the standard discrete nonlinear Schroedinger equation. We show that, away from that integrable limit, the mobile pulse is dressed by a background of resonant plane waves with wavevectors given by a certain selection rule. This background is seen to be essential for supporting mobile localization in the absence of integrability. We show how the variations of the localized pulse energy during its motion are balanced by the interaction with this background, allowing the localization mobility along the lattice.
Bottomonium above Deconfinement in Lattice Nonrelativistic QCD
International Nuclear Information System (INIS)
Aarts, G.; Kim, S.; Lombardo, M. P.; Oktay, M. B.; Ryan, S. M.; Sinclair, D. K.; Skullerud, J.-I.
2011-01-01
We study the temperature dependence of bottomonium for temperatures in the range 0.4T c c , using nonrelativistic dynamics for the bottom quark and full relativistic lattice QCD simulations for N f =2 light flavors on a highly anisotropic lattice. We find that the Υ is insensitive to the temperature in this range, while the χ b propagators show a crossover from the exponential decay characterizing the hadronic phase to a power-law behavior consistent with nearly free dynamics at T≅2T c .
Topology in dynamical lattice QCD simulations
Energy Technology Data Exchange (ETDEWEB)
Gruber, Florian
2012-08-20
Lattice simulations of Quantum Chromodynamics (QCD), the quantum field theory which describes the interaction between quarks and gluons, have reached a point were contact to experimental data can be made. The underlying mechanisms, like chiral symmetry breaking or the confinement of quarks, are however still not understood. This thesis focuses on topological structures in the QCD vacuum. Those are not only mathematically interesting but also closely related to chiral symmetry and confinement. We consider methods to identify these objects in lattice QCD simulations. Based on this, we explore the structures resulting from different discretizations and investigate the effect of a very strong electromagnetic field on the QCD vacuum.
Natural uranium lattice in heavy water
International Nuclear Information System (INIS)
Girard, Y.; Koechlin, J.C.; Moreau, J.; Naudet, R.
1959-01-01
A group of Laplacian determinations have been made under critical running conditions in a heavy water pile specially constructed to this end using either complete lattices or samples of lattices employing a two-zone method. The experimental equipment is briefly described: it has been devised to allow rapid modifications of the charge. The methods of measurement employed are also summarily described one operates either by flux charts in the case of lattices which are then used as references, or by progressive replacement of the bars by concentric rings and measurements of the reactivity. In this case, one attempts to obtain the difference between the material laplacian of the central unknown lattice and that of the reference lattice. The method has been specially develop ped to give precision. Results of Laplacian measurements for all these lattice types are presented, allowing the construction of a set of curves as a function of the separation. Various other effects have also been measured: the equivalent reactivity of a mm of water - anisotropy - temperature effect, etc. However in this first attack on the problem, the measurement of a large variety of Laplacian has been carried out, rather than careful measurements in particular cases. It is in this spirit that the interpretation of the results has been made. As a large number of very complex phenomena still escape the possibilities of the calculation, it is considered that a certain number of adjustments are necessary; now these can only give the desired efficiency in forecasting results if they refer to a sufficiently great number of experimental data. It is necessary then to connect the measurements closely on with the other whilst, at the same time, subdividing them according to logically deduced formulae. The principal source of trouble has been that of coherence. The rules governing the calculations employed in the interpretation of the data are given. In the first instance simple formula are used: first of
Induced Chern-Simons term in lattice QCD at finite temperature
International Nuclear Information System (INIS)
Borisenko, O.A.; Petrov, V.K.; Zinov'ev, G.M.
1992-01-01
The general conditions when the Chern-Simons action could arise (in continuum limit) as non universal contribution of fermionic determinant of finite-temperature lattice QCD are formulated. The dependence of this action coefficient on non universal parameters (a chemical potential, vacuum features, etc.) is investigated in detail. Special attention is paid to the role of possible 0 >-condensate existence. 42 refs. (author)
Common Variants in the COL4A4 Gene Confer Susceptibility to Lattice Degeneration of the Retina
Meguro, Akira; Ideta, Hidenao; Ota, Masao; Ito, Norihiko; Ideta, Ryuichi; Yonemoto, Junichi; Takeuchi, Masaki; Uemoto, Riyo; Nishide, Tadayuki; Iijima, Yasuhito; Kawagoe, Tatsukata; Okada, Eiichi; Shiota, Tomoko; Hagihara, Yuta; Oka, Akira
2012-01-01
Lattice degeneration of the retina is a vitreoretinal disorder characterized by a visible fundus lesion predisposing the patient to retinal tears and detachment. The etiology of this degeneration is still uncertain, but it is likely that both genetic and environmental factors play important roles in its development. To identify genetic susceptibility regions for lattice degeneration of the retina, we performed a genome-wide association study (GWAS) using a dense panel of 23,465 microsatellite...
Phase structure of lattice N=4 super Yang-Mills
DEFF Research Database (Denmark)
Catterall, Simon; Damgaard, Poul H.; DeGrand, Thomas
2012-01-01
We make a first study of the phase diagram of four-dimensional N = 4 super Yang-Mills theory regulated on a space-time lattice. The lattice formulation we employ is both gauge invariant and retains at all lattice spacings one exactly preserved supersymmetry charge. Our numerical results are consi......We make a first study of the phase diagram of four-dimensional N = 4 super Yang-Mills theory regulated on a space-time lattice. The lattice formulation we employ is both gauge invariant and retains at all lattice spacings one exactly preserved supersymmetry charge. Our numerical results...
Lattice formulation of a two-dimensional topological field theory
International Nuclear Information System (INIS)
Ohta, Kazutoshi; Takimi, Tomohisa
2007-01-01
We investigate an integrable property and the observables of 2-dimensional N=(4,4) topological field theory defined on a discrete lattice by using the 'orbifolding' and 'deconstruction' methods. We show that our lattice model is integrable and, for this reason, the partition function reduces to matrix integrals of scalar fields on the lattice sites. We elucidate meaningful differences between a discrete lattice and a differentiable manifold. This is important for studying topological quantities on a lattice. We also propose a new construction of N=(2,2) supersymmetric lattice theory, which is realized through a suitable truncation of scalar fields from the N=(4,4) theory. (author)
On the hierarchical lattices approximation of Bravais lattices: Specific heat and correlation length
International Nuclear Information System (INIS)
Tsallis, C.
1984-01-01
Certain types of real-space renormalization groups (which essentially approximate Bravais lattices through hierarchical ones) do not preserve standard thermodynamic convexity properties. It is pointed out that this serious defect is not intrinsic to any real-space renormalization. It can be avoided if form-invariance (under uniform translation of the energy scale) of the equation connecting the Bravais lattice (which is intended to study) to the hierarchical one (which approximates it) is demanded. In addition to that expressions for the critical exponentes ν and α corresponding to hierarchical lattices are analysed; these are consistent with Melrose recent analysis of the fractal intrinsic dimensionality. (Author) [pt
Directory of Open Access Journals (Sweden)
Dawson Andrew H
2010-06-01
Full Text Available Abstract Background Cardiac toxicity due to ingestion of oleander plant seeds in Sri Lanka and some other South Asian countries is very common. At present symptomatic oleander seed poisoning carries a mortality of 10% in Sri Lanka and treatment of yellow oleander poisoning is limited to gastric decontamination and atropine administration. The only proven effective antidote is digoxin antibodies but these are not available for routine use because of the high cost. The main objective of this study is to investigate the effectiveness of a new and inexpensive antidote for patients with life threatening arrhythmias due oleander poisoning. Method/design We set up a randomised double blind clinical trial to assess the effectiveness of Fructose 1, 6 diphosphate (FDP in acute yellow oleander poisoning patients admitted to the adult medical wards of a tertiary hospital in Sri Lanka. Patients will be initially resuscitated following the national guidelines and eligible patients will be randomised to receive either FDP or an equal amount of normal saline. The primary outcome measure for this study is the sustained reversion to sinus rhythm with a heart rate greater than 50/min within 2 hours of completion of FDP/placebo bolus. Secondary outcomes include death, reversal of hyperkalaemia on the 6, 12, 18 and 24 hour samples and maintenance of sinus rhythm on the holter monitor. Analysis will be on intention-to-treat. Discussion This trial will provide information on the effectiveness of FDP in yellow oleander poisoning. If FDP is effective in cardiac glycoside toxicity, it would provide substantial benefit to the patients in rural Asia. The drug is inexpensive and thus could be made available at primary care hospitals if proven to be effective. Trial Registration Current Controlled trial ISRCTN71018309
Ghannoum, Marc; Hoffman, Robert S; Mowry, James B; Lavergne, Valery
2014-01-01
Morbidity and mortality from toxic alcohols like ethylene glycol and methanol remain prevalent worldwide. The introduction of fomepizole, a potent blocker of alcohol dehydrogenase, has modified current practice over the last 15 years. The aim of the study was to describe the characteristics of toxic alcohol poisoning reported to US poison centers, the trends in the incidence of antidote use and hemodialysis treatment, as well as the related mortality. A retrospective study of all electronic entries from the AAPCC National Poison Data System database, from the years 2000 to 2013 was reviewed. When considering all exposures, the great majority of patients had a benign outcome. Major effects (e.g., life threatening) occurred in 2.1% and 4.9% of methanol and ethylene glycol cases, respectively. Mortality rates were similar for both toxic alcohols, approximately 0.6%. When only considering ingestions reported to healthcare facilities, a major effect was reported in 9.5% and 20.5%, and the mortality rate was 2.9% and 2.4% for methanol and ethylene glycol exposures, respectively, and remained constant over time. The use of fomepizole increased statistically over the study period while that of ethanol decreased, until it became proportionally negligible by 2012-2013. The use of hemodialysis significantly decreased in "Early" ethylene glycol exposures during the study period. Similar to other reports, it appears that the use of fomepizole has largely supplanted ethanol as the antidote of choice in toxic alcohol exposures and may decrease the requirements for hemodialysis in patients poisoned with ethylene glycol who have no acidosis and normal kidney function. © 2014 Wiley Periodicals, Inc.
Directory of Open Access Journals (Sweden)
Suryadi Budi Utomo
2013-08-01
Full Text Available A research has been conducted to synthesize tetrakis-N,N,N-trimethylammoniummethyl-C-3,4-dimethoxyphenylcalix[4]resorcinarene iodide from vanillin and investigate its antidote capability for Cr(VI intoxication. The synthesis was carried out in four steps i.e. (1 O-alkylation of 4-hydroxy-3-methoxybenzaldehyde, (2 HCl-catalyzed condensation of 3,4-dimethoxybenzaldehyde with resorcinol, (3 Mannich reaction of C-3,4-dimethoxyphenylcalix[4]resorcinarene with formaldehyde and dimethylamine in the presence of HCl to yield tetrakis-N,N-dimethylaminomethyl-C-3,4-dimethoxyphenylcalix[4]resorcinarene, and (4 treatment the Mannich base with methyl iodide to produce the quaternary ammonium salt of tetrakis-N,N,N-trimethylammoniummethyl-C-3,4-dimethoxyphenylcalix[4]resorcinarene iodide. According to the analysis of 1H-NMR spectrometer, the targeted compounds tend to exist in the chair (C2h conformation. The capability of resorcinarene for Cr(VI antidote was examined by orally injection method on mice groups. Based on LD50 determination, the resorcinarene was classified as non toxic compound according to Loomis criteria. Therapeutic using quaternary ammonium-modified resorcinarene was able to reduce metal concentrations of Cr(VI in liver, kidney, and serum in the magnitude of 78.30; 85.72, and 88.79%, respectively. The higher dose of drug administered the greater decrease in the level of heavy metal. Judging from the amount of milligrams of reduced chromium per gram of organ, kidney is the organ having highest decreasing metal concentrations.
Fuel lattice design using heuristics and new strategies
Energy Technology Data Exchange (ETDEWEB)
Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R. [ININ, Carretera Mexico-Toluca s/n, Ocoyoacac 52750, Estado de Mexico (Mexico); Pelta, D. A. [ETS Ingenieria Informatica y Telecomunicaciones, Universidad de Granada, Daniel Saucedo Aranda s/n, 18071 Granada (Spain); Campos S, Y., E-mail: juanjose.ortiz@inin.gob.m [IPN, Escuela Superior de Fisica y Matematicas, Unidad Profesional Adolfo Lopez Mateos, Edif. 9, 07738 Mexico D. F. (Mexico)
2010-10-15
This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)
Fuel lattice design using heuristics and new strategies
International Nuclear Information System (INIS)
Ortiz S, J. J.; Castillo M, J. A.; Torres V, M.; Perusquia del Cueto, R.; Pelta, D. A.; Campos S, Y.
2010-10-01
This work show some results of the fuel lattice design in BWRs when some allocation pin rod rules are not taking into account. Heuristics techniques like Path Re linking and Greedy to design fuel lattices were used. The scope of this work is to search about how do classical rules in design fuel lattices affect the heuristics techniques results and the fuel lattice quality. The fuel lattices quality is measured by Power Peaking Factor and Infinite Multiplication Factor at the beginning of the fuel lattice life. CASMO-4 code to calculate these parameters was used. The analyzed rules are the following: pin rods with lowest uranium enrichment are only allocated in the fuel lattice corner, and pin rods with gadolinium cannot allocated in the fuel lattice edge. Fuel lattices with and without gadolinium in the main diagonal were studied. Some fuel lattices were simulated in an equilibrium cycle fuel reload, using Simulate-3 to verify their performance. So, the effective multiplication factor and thermal limits can be verified. The obtained results show a good performance in some fuel lattices designed, even thought, the knowing rules were not implemented. A fuel lattice performance and fuel lattice design characteristics analysis was made. To the realized tests, a dell workstation was used, under Li nux platform. (Author)
Lattice Boltzmann method for the fractional advection-diffusion equation
Zhou, J. G.; Haygarth, P. M.; Withers, P. J. A.; Macleod, C. J. A.; Falloon, P. D.; Beven, K. J.; Ockenden, M. C.; Forber, K. J.; Hollaway, M. J.; Evans, R.; Collins, A. L.; Hiscock, K. M.; Wearing, C.; Kahana, R.; Villamizar Velez, M. L.
2016-04-01
Mass transport, such as movement of phosphorus in soils and solutes in rivers, is a natural phenomenon and its study plays an important role in science and engineering. It is found that there are numerous practical diffusion phenomena that do not obey the classical advection-diffusion equation (ADE). Such diffusion is called abnormal or superdiffusion, and it is well described using a fractional advection-diffusion equation (FADE). The FADE finds a wide range of applications in various areas with great potential for studying complex mass transport in real hydrological systems. However, solution to the FADE is difficult, and the existing numerical methods are complicated and inefficient. In this study, a fresh lattice Boltzmann method is developed for solving the fractional advection-diffusion equation (LabFADE). The FADE is transformed into an equation similar to an advection-diffusion equation and solved using the lattice Boltzmann method. The LabFADE has all the advantages of the conventional lattice Boltzmann method and avoids a complex solution procedure, unlike other existing numerical methods. The method has been validated through simulations of several benchmark tests: a point-source diffusion, a boundary-value problem of steady diffusion, and an initial-boundary-value problem of unsteady diffusion with the coexistence of source and sink terms. In addition, by including the effects of the skewness β , the fractional order α , and the single relaxation time τ , the accuracy and convergence of the method have been assessed. The numerical predictions are compared with the analytical solutions, and they indicate that the method is second-order accurate. The method presented will allow the FADE to be more widely applied to complex mass transport problems in science and engineering.
Supersymmetry and the lattice: A reconciliation?
International Nuclear Information System (INIS)
Curci, G.
1987-01-01
Contrary to common prejudice, we claim that supersymmetric gauge theories can be studied non-perturbatively on the lattice (by using known ideas and techniques). We discuss in detail super-Yang-Mills theory and propose some explicit measurements which are both physically interesting and within present or near-future computer capabilities. (orig.)
Lattice QCD on a beowulf cluster
International Nuclear Information System (INIS)
Kima, Seyong
2000-01-01
Using commodity component personal computers based on Alpha processor and commodity network devices and a switch, we built an 8-node parallel computer. GNU/Linux is chosen as an operating system and message passing libraries such as PVM, LAM, and MPICH have been tested as a parallel programming environment. We discuss our lattice QCD project for a heavy quark system on this computer