294 research outputs found
Stringy cosmic strings in matter coupled N=2, d=4 supergravity
We extend the system of ungauged N=2, d=4 supergravity coupled to vector
multiplets and hypermultiplets with 2-form potentials. The maximal number of
2-form potentials that one may introduce is equal to the number of isometries
of either the special Kaehler or quaternionic Kaehler sigma model. We show that
the local supersymmetry algebra can be realized on the 2-form potentials. These
2-forms couple electrically to strings which we refer to as stringy cosmic
strings. The 1/2 BPS bosonic world-sheet actions for these strings are
constructed and we discuss the properties of the 1/2 BPS stringy cosmic string
solutions.Comment: 36 pages, added references, corrected typos, modificated Appendix
Tricritical gravity waves in the four-dimensional generalized massive gravity
We construct a generalized massive gravity by combining quadratic curvature
gravity with the Chern-Simons term in four dimensions. This may be a candidate
for the parity-odd tricritical gravity theory. Considering the AdS vacuum
solution, we derive the linearized Einstein equation, which is not similar to
that of the three dimensional (3D) generalized massive gravity. When a
perturbed metric tensor is chosen to be the Kerr-Schild form, the linearized
equation reduces to a single massive scalar equation. At the tricritical points
where two masses are equal to -1 and 2, we obtain a log-square wave solution to
the massive scalar equation. This is compared to the 3D tricritical generalized
massive gravity whose dual is a rank-3 logarithmic conformal field theory.Comment: 17 pages, 1 figure, version to appear in EPJ
Special Geometry of Euclidean Supersymmetry III: the local r-map, instantons and black holes
We define and study projective special para-Kahler manifolds and show that
they appear as target manifolds when reducing five-dimensional vector
multiplets coupled to supergravity with respect to time. The dimensional
reductions with respect to time and space are carried out in a uniform way
using an epsilon-complex notation. We explain the relation of our formalism to
other formalisms of special geometry used in the literature. In the second part
of the paper we investigate instanton solutions and their dimensional lifting
to black holes. We show that the instanton action, which can be defined after
dualising axions into tensor fields, agrees with the ADM mass of the
corresponding black hole. The relation between actions via Wick rotation, Hodge
dualisation and analytic continuation of axions is discussed.Comment: 72 pages, 2 figure
Green manure in coffee systems in the region of Zona da Mata, Minas Gerais: characteristics and kinetics of carbon and nitrogen mineralization.
The use of green manure may contribute to reduce soil erosion and increase the soil organic matter content and N availability in coffee plantations in the Zona da Mata, State of Minas Gerais, in Southeastern Brazil. The potential of four legumes (A. pintoi, C. mucunoides, S. aterrimum and S. guianensis)to produce above-ground
biomass, accumulate nutrients and mineralize N was studied in two coffee plantations of subsistence farmers under different climate conditions. The biomass production of C. mucunoides was influenced by the shade of the coffee plantation.C. mucunoides tended to mineralize more N than the other legumes due to the low polyphenol content and polyphenol/N ratio. In the first year, the crop establishment of A. pintoi in the area took longer than of the other legumes, resulting in lower biomass production and N2 fixation. In the long term, cellulose was the main
factor controlling N mineralization. The biochemical characteristics, nutrient accumulation and biomass production of the legumes were greatly influenced by
the altitude and position of the area relative to the sun
Spin Glass Behavior in RuSr2Gd1.5Ce0.5Cu2O10
The dynamics of the magnetic properties of polycrystalline
RuSr2Gd1.5Ce0.5Cu2O10 (Ru-1222) have been studied by ac susceptibility and dc
magnetization measurements, including relaxation and ageing studies. Ru-1222 is
a reported magneto-superconductor with Ru spins magnetic ordering at
temperatures near 100 K and superconductivity in Cu-O2 planes below Tc ~ 40 K.
The exact nature of Ru spins magnetic ordering is still debated and no
conclusion has been reached yet. In this work, a frequency-dependent cusp was
observed in ac susceptibility vs. T measurements, which is interpreted as a
spin glass transition. The change in the cusp position with frequency follows
the Vogel-Fulcher law, which is commonly accepted to describe a spin glass with
magnetically interacting clusters. Such interpretation is supported by
themoremanaent magnetization (TRM) measurements at T = 60 K. TRM relaxations
are well described by a stretched exponential relation, and present significant
ageing effects.Comment: 4 pages, 6 figures, submitted to Phys. Rev.
Goats in a comfortable and stressed environment consuming saline water: performance, digestibility, nitrogen balance, and urinary mineral concentrations
ABSTRACT The objective was to evaluate the effect of water salinity and environmental temperature on the nutrient consumption, digestibility, nitrogen balance, and mineral excretion of creole goats. Thirty-six males with an average age of 5.0±0.6 months and an average weight of 20.0±2.3kg were housed in metabolic cages. They are distributed in a completely randomized design, with a 2×3 type crossover (2 temperatures (T1 = 26±0.6ºC and T2 = 32±1.2ºC) and three levels of salinity (1.0, 6.0, and 12.0 dS m-1). The temperature influenced (P0.05) of temperatures or water salinity levels; the animals consumed and retained averages of 10.31 and 4.19 g day-1 of nitrogen in the body, respectively. The different water salinity levels influenced (P<0.05) water intake and increased the excretions of potassium and sodium in urine. Total solids levels ranging from 640 to 9,600mg L-1 in water for goats increase water consumption, as does urine potassium and sodium excretion in urine
Responses of IgE, IgG1, and IgG4 to concanavalin A-binding Blomia tropicalis antigens in allergic patients
Non-Kaehler Heterotic String Compactifications with non-zero fluxes and constant dilaton
We construct new explicit compact supersymmetric valid solutions with
non-zero field strength, non-flat instanton and constant dilaton to the
heterotic equations of motion in dimension six. We present balanced Hermitian
structures on compact nilmanifolds in dimension six satisfying the heterotic
supersymmetry equations with non-zero flux, non-flat instanton and constant
dilaton which obey the three-form Bianchi identity with curvature term taken
with respect to either the Levi-Civita, the (+)-connection or the Chern
connection. Among them, all our solutions with respect to the (+)-connection on
the compact nilmanifold satisfy the heterotic equations of motion.Comment: LaTeX, 16 pp., no figures, new Theorem 1.1, references adde
Technische en economische mogelijkheden voor het zuiveren van spuiwater
De waterkringloop op substraatbedrijven moet verder gesloten worden. De resultaten van de diverse deelprojecten van het onderzoeksproject Glastuinbouw Waterproof-substraatteelt leiden tot mogelijkheden om de hoeveelheid spui (aantal m 3 ) naar sloot of riool te verminderen en tot apparatuur om de kwaliteit van de resterende te lozen hoeveelheid spuiwater te verbeteren (minder gewasbeschermingsmiddelen (GBM), stikstof en fosfaat). In deze rapportage wordt verslag gedaan van de technische en economische mogelijkheden van zuiveringsapparatuur om telers en beleidsmakers een (globaal) advies te kunnen geven. De belangrijkste redenen voor spui zijn ophoping van natrium, het aanwezig zijn van groeiremmende stoffen, het overlopen van opslagtanks, onbalans in de voedingsoplossing, de angst voor ziekten, weg laten lopen van de eerste drain bij de start van een teelt of gewoon de wens te willen verversen. Binnen de gewassen varieert de hoeveelheid spui sterk, van nagenoeg nul tot meer dan 1250 m 3 /ha/jaar
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