590 research outputs found
Purely twistorial string with canonical twistor field quantization
We introduce new purely twistorial scale-invariant action describing the
composite bosonic D=4 Nambu-Goto string with target space parametrized by the
pair of D=4 twistors. We show that by suitable gauge fixing of local scaling
one gets the bilinear twistorial action and canonical quantization rules for
the two-dimensional twistor-string fields. We consider the Poisson brackets of
all constraints characterizing our model and we obtain four first class
constraints describing two Virasoro constraints and two U(1)xU(1) Kac-Moody
(KM) local phase transformations.Comment: v3: 6p.(extended version), in press in Physical Review
Degenerate Odd Poisson Bracket on Grassmann Variables
A linear degenerate odd Poisson bracket (antibracket) realized solely on
Grassmann variables is presented. It is revealed that this bracket has at once
three nilpotent -like differential operators of the first, the second
and the third orders with respect to the Grassmann derivatives. It is shown
that these -like operators together with the Grassmann-odd nilpotent
Casimir function of this bracket form a finite-dimensional Lie superalgebra.Comment: 5 pages, LATEX. Corrections of misprints. The relation (23) is adde
Modeling of Condensation Reaction of Aniline to Diphenylamine by PM7 Method
Modeling of the condensation reaction to diphenylamine was carried out by PM7 method with acid catalysts: tetrafluoroborate, oxytrifluoroborate and anilinium oxytetratrifluoroborate. The calculated data prove that the formation of a few protonated forms of aniline is possible during the reaction of aniline with acids. Only positively charged p- and o-[sigma]-complexes are capable of further interaction with aniline. The stage of intramolecular proton transfer from the primary to the secondary amino groups of intermediates of aniline reaction with proton aniline ?-complex determines the condensation rate of aniline to diphenylamine with acid catalysts. A catalyst anion can form ionic and ion-dipole complexes with reaction mixture components and can influence the distribution of electron density in reactants and their reactivity with its field
Field Representations of Vector Supersymmetry
We study some field representations of vector supersymmetry with superspin
Y=0 and Y=1/2 and nonvanishing central charges. For Y=0, we present two
multiplets composed of four spinor fields, two even and two odd, and we provide
a free action for them. The main differences between these two multiplets are
the way the central charge operators act and the compatibility with the
Majorana reality condition on the spinors. One of the two is related to a
previously studied spinning particle model. For Y=1/2, we present a multiplet
composed of one even scalar, one odd vector and one even selfdual two-form,
which is a truncation of a known representation of the tensor supersymmetry
algebra in Euclidean spacetime. We discuss its rotation to Minkowski spacetime
and provide a set of dynamical equations for it, which are however not derived
from a Lagrangian. We develop a superspace formalism for vector supersymmetry
with central charges and we derive our multiplets by superspace techniques.
Finally, we discuss some representations with vanishing central charges.Comment: 37 page
The Effect of Condensed Tannins in Lotus spp. on the Lesser Migratory Grasshopper
Hatchling grasshoppers (Melanoplus sanguinipes Fab.) fed one accession of field grown big trefoil (Lotus uliginosis Schkuhr) containing a tannin content of 56 mg. g-1 FW, had a significantly lower mean weight than hatchlings fed field grown Lotus species and accessions with lower tannin content. Adult female grasshoppers fed L. uliginosis foliage with 32.3 mg.g-1 FW tannin also ate more feed and had a 2-fold higher gut trypsin and chymotrypsin activity than adults fed low tannin L. corniculatus foliage (0.13 mg.g-1 FW tannin). In more controlled experiments, growth at 20o C or 30o C was used to increase tannin in rooted cuttings of L. uliginosis to concentrations ranging from 7 to 195 mg.g-1 FW. Hatchling weight decreased as a function of dietary tannin concentration when fed these clones. Both hatchling weight and survival were affected when hatchlings were fed pelleted wheat seedlings supplemented with purified L. uliginosis tannin preparations
APATITE SHELLS OF THE DEVONIAN FORAMINIFERS (SAFYANOVSKY COPPER-SULPHIDE DEPOSIT, MIDDLE URAL)
Relevance of the work is due to the possibility of a detailed study of Devonian foraminifers with apatite shells and the reconstruction of specific conditions for their formation. Foraminifer shells are morphologically similar to Parathurammina aff. tamarae L. Petrova, 1981, the Eifelian-the Givetian, which were found in thin sections of samples of carboniferous and chiselly aleuropelites of the ore-bearing strata of the Safyanovsky copper-sulphide deposit (Middle Urals) for the first time.
Purpose of work. Detailed study of the shells of Devonian foraminifers similar to Parathurammina aff. tamarae L. Petrova, 1981, as well as reconstruction of sedimentation conditions for carboniferous and chiselly rocks of the ore-bearing strata of the Safyanovsky copper-sulphide deposit.
Research methodology. Shells were studied in thin sections of carboniferous and chiselly aleuropelite samples. The detailed study of morphology and composition of the shells was carried out using a scanning electron microscope JSM-6390LV (JEOL) with an energy-dispersive spectrometer Inca Energy 450, an electron microscope Tescan and an electron probe microanalyzer Cameca SX100.
Results. Size and morphology of the shells were determined; it was also found that the walls of the shells of the studied foraminifers were represented by fluorapatite. It was assumed that initially they were calcareous, and subsequently were replaced by apatite and quartz. However, more detailed studies did not reveal traces of substitution of carbonate rock for apatite.
Conclusions. Compared with Parathurammina aff. tamarae L. Petrova, 1981, shells have a reduced size and a smaller number of fauces, which can be explained by unfavorable habitats in a shallow sea basin, where carbonate sedimentation was suppressed by a significant influx of volcanic material. The presence of sulfide minerals in nucleus of shells may indicate to the specific habitat (pH of the environment, salinity of supra-bottom water) of foraminifers. Findings of fossils of green, siphon algae together with studied foraminifers indicate that formation of the original substrate took place in near-surface layers (up to 200 m) of the photic zone of seas
Big Data Driven Customer Insights for SMEs in Redistributed Manufacturing
© 2017 The Authors. Published by Elsevier. Redistributed manufacturing (RdM) refers to manufacturing business models, strategies, systems and technologies that change the economics and organization of manufacturing, particularly related to location and scale. Small-scale manufacturing has the potential to help tailor products to satisfy the specific needs of consumers different in terms of geographical location, cultural roots, improve sustainability and drive the society towards circular economy. While RdM has the great potential to deliver this, currently, very little has been understood on how RdM could help SMEs for gaining economic benefits due to the constraint of their business model, lack of understanding on customers, limited resource commitment on R & D, marketing and sales, supply chain integration, etc. Similarly user-driven design and customer-insights delivered through 'big data' analytics has the potentially to be highly beneficial for manufacturing SME and little is known of how they can be combined with RdM to benefit SMEs. Hence, they may impose risks on the business and operation of SMEs should poor choices be made or systems be implemented badly. The economic importance of SMEs within the UK and Europe is long established with manufacturing SMEs accounting for 60% of all private sector jobs in the UK. Within the European Union the overwhelming majority of companies (trading in the non-financial sectors) were SMEs (99.8%), employing 89.7 million people (67.1% of the workforce). This paper reports some of the results of an initial exploratory survey of manufacturing SMEs within the United Kingdom. Focusing on their background and status, and their current understanding and interests in RdM, big customer analytics and related topics
An Automated Cloud-based Big Data Analytics Platform for Customer Insights
Product reviews have a significant influence on strategic decisions for both businesses and customers on what to produce or buy. However, with the availability of large amounts of online information, manual analysis of reviews is costly and time consuming, as well as being subjective and prone to error. In this work, we present an automated scalable cloud-based system to harness big customer reviews on products for gaining customer insights through data pipeline from data acquisition, analysis to visualisation in an efficient way. The experimental evaluation has shown that the proposed system achieves good performance in terms of accuracy and computing time
Measurement of the Rate of Muon Capture in Hydrogen Gas and Determination of the Proton's Pseudoscalar Coupling
The rate of nuclear muon capture by the proton has been measured using a new
experimental technique based on a time projection chamber operating in
ultra-clean, deuterium-depleted hydrogen gas at 1 MPa pressure. The capture
rate was obtained from the difference between the measured
disappearance rate in hydrogen and the world average for the decay
rate. The target's low gas density of 1% compared to liquid hydrogen is key to
avoiding uncertainties that arise from the formation of muonic molecules. The
capture rate from the hyperfine singlet ground state of the atom is
measured to be , from which the induced
pseudoscalar coupling of the nucleon, , is
extracted. This result is consistent with theoretical predictions for
that are based on the approximate chiral symmetry of QCD.Comment: submitted to Phys.Rev.Let
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