2,154 research outputs found
Noncommutative Maxwell-Chern-Simons theory, duality and a new noncommutative Chern-Simons theory in d=3
Noncommutative Maxwell-Chern-Simons theory in 3-dimensions is defined in
terms of star product and noncommutative fields. Seiberg-Witten map is employed
to write it in terms of ordinary fields. A parent action is introduced and the
dual action is derived. For spatial noncommutativity it is studied up to second
order in the noncommutativity parameter \theta. A new noncommutative
Chern-Simons action is defined in terms of ordinary fields, inspired by the
dual action. Moreover, a transformation between noncommuting and ordinary
fields is proposed.Comment: 7 pages. Some comments, new eqs. and references added. The version to
be published in Phys. Lett.
Quantification of soil mapping by digital analysis of LANDSAT data
Soil survey mapping units are designed such that the dominant soil represents the major proportion of the unit. At times, soil mapping delineations do not adequately represent conditions as stated in the mapping unit descriptions. Digital analysis of LANDSAT multispectral scanner (MSS) data provides a means of accurately describing and quantifying soil mapping unit composition. Digital analysis of LANDSAT MSS data collected on 9 June 1973 was used to prepare a spectral soil map for a 430-hectare area in Clinton County, Indiana. Fifteen spectral classes were defined, representing 12 soil and 3 vegetation classes. The 12 soil classes were grouped into 4 moisture regimes based upon their spectral responses; the 3 vegetation classes were grouped into one all-inclusive class
A family as a basic value of youth
The research of vital values of a modern person is an actual problem of sociology. Youth as a specific category represents special interest for scientists. In the article the results of author's and other sociological researches of vital values of youth are presented. The authors come to the conclusion that a family holds a leading position in the system of vital values of youth.Исследование жизненных ценностей современного человека – актуальная проблема социологической науки. Молодежь как специфическая категория представляет особый интерес для ученых. В статье приводятся результаты авторских и других социологических исследований жизненных ценностей молодежи. Авторами делается вывод о лидирующем положении семьи в системе жизненных ценностей современной молодежи
Uncertainty-principle noise in vacuum-tunneling transducers
The fundamental sources of noise in a vacuum-tunneling probe used as an
electromechanical transducer to monitor the location of a test mass are
examined using a first-quantization formalism. We show that a tunneling
transducer enforces the Heisenberg uncertainty principle for the position and
momentum of a test mass monitored by the transducer through the presence of two
sources of noise: the shot noise of the tunneling current and the momentum
fluctuations transferred by the tunneling electrons to the test mass. We
analyze a number of cases including symmetric and asymmetric rectangular
potential barriers and a barrier in which there is a constant electric field.
Practical configurations for reaching the quantum limit in measurements of the
position of macroscopic bodies with such a class of transducers are studied
Spin-1/2 particles moving on a 2D lattice with nearest-neighbor interactions can realize an autonomous quantum computer
What is the simplest Hamiltonian which can implement quantum computation
without requiring any control operations during the computation process? In a
previous paper we have constructed a 10-local finite-range interaction among
qubits on a 2D lattice having this property. Here we show that
pair-interactions among qutrits on a 2D lattice are sufficient, too, and can
also implement an ergodic computer where the result can be read out from the
time average state after some post-selection with high success probability.
Two of the 3 qutrit states are given by the two levels of a spin-1/2 particle
located at a specific lattice site, the third state is its absence. Usual
hopping terms together with an attractive force among adjacent particles induce
a coupled quantum walk where the particle spins are subjected to spatially
inhomogeneous interactions implementing holonomic quantum computing. The
holonomic method ensures that the implemented circuit does not depend on the
time needed for the walk.
Even though the implementation of the required type of spin-spin interactions
is currently unclear, the model shows that quite simple Hamiltonians are
powerful enough to allow for universal quantum computing in a closed physical
system.Comment: More detailed explanations including description of a programmable
version. 44 pages, 12 figures, latex. To appear in PR
Synthesis and Antimalarial Activity of 11 Dispiro-1,2,4,5-tetraoxane Analogues of WR 148999. 7,8,15,16-Tetraoxadispiro[5.2.5.2]hexadecanes Substituted at the 1 and 10 Positions with Unsaturated and Polar Functional Groups
Eleven novel dispiro-1,2,4,5-tetraoxanes 3 bearing unsaturated and polar functional groups were designed to enhance the oral antimalarial activity of the prototype tetraoxane 2 (WR 148999). With the exception of 3g and 3h, tetraoxanes 3 were available via the peroxidation of corresponding cyclohexanone derivatives in H2SO4/CH3CN. Tetraoxanes 3g and 3h were prepared by hydrolysis of ester tetraoxanes 3e and 3i, respectively. Five of the 11 tetraoxanes were inactive, but six tetraoxanes had IC50 values of 6-26 nM against the K1 and NF54 strains of Plasmodium falciparum compared to corresponding IC50 values of 28 and 39 nM for 2, and 10 and 12 nM for artemisinin (1). Ester tetraoxane 3e was the most active in vitro, some 2-fold more potent than 1. However, none of the six tetraoxanes active in vitro were as effective as either 1 or 2 in vivo; at single doses of 100 mg/kg most possessed little to no vivo activity in mice infected with Plasmodium berghei. Unsaturated tetraoxane 3a was uniquely more active when administered per os (po) than subcutan (sc). For this series of tetraoxanes, the discrepancy between vitro and vivo activities underscores the limitations of conclusions drawn solely from in vitro antimalarial data and illustrates a practical benefit of complementary single-dose in vivo antimalarial screens
Metallicity, temperature, and gravity scales of M subdwarfs
The aim of the project is to define a metallicity/gravity/temperature scale
vs spectral types for metal-poor M dwarfs.
We obtained intermediate-resolution ultraviolet (R~3300), optical (R~5400),
and near-infrared (R~3900) spectra of 43 M subdwarfs (sdM), extreme subdwarfs
(esdM), and ultra-subdwarfs (usdM) with the X-shooter spectrograph on the
European Southern Observatory Very Large Telescope. We compared our atlas of
spectra to the latest BT-Settl synthetic spectral energy distribution over a
wide range of metallicities, gravities, and effective temperatures to infer the
physical properties for the whole M dwarf sequence (M0--M9.5) at sub-solar
metallicities and constrain the latest state-of-the-art atmospheric models.
The BT-Settl models reproduce well the observed spectra across the 450-2500
nm wavelength range except for a few regions. We find that the best fits are
obtained for gravities of log(g) = 5.0-5.5 dex for the three metal classes. We
infer metallicities of [Fe/H] = -0.5, -1.5, and -2.0+/-0.5 dex and effective
temperatures of 3700-2600 K, 3800-2900 K, and 3700-2900 K for subdwarfs,
extreme subdwarfs, and ultra-subdwarfs, respectively. Metal-poor M dwarfs tend
to be warmer by about 200+/-100 K and exhibit higher gravity than their
solar-metallicity counterparts. We derive abundances of several elements (Fe,
Na, K, Ca, Ti) for our sample but cannot describe their atmospheres with a
single metallicity parameter. Our metallicity scale expands the current scales
available for midly metal-poor planet-host low-mass stars. Our compendium of
moderate-resolution spectra covering the 0.45--2.5 micron range represents an
important legacy value for large-scale surveys and space missions to come.Comment: 31 pages, 4 pages, 4 tables + 1 appendix with 12 figures and 5
tables. Accepted for publication in A&A. Version prior to language editio
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