4,093 research outputs found
Sharp values for the constants in the polynomial Bohnenblust-Hille inequality
In this paper we prove that the complex polynomial Bohnenblust-Hille constant
for -homogeneous polynomials in is exactly
. We also give the exact value of the real polynomial
Bohnenblust-Hille constant for -homogeneous polynomials in .
Finally, we provide lower estimates for the real polynomial Bohnenblust-Hille
constant for polynomials in of higher degrees.Comment: 16 page
-AlO sapphire and rubies deformed by dual basal slip at intermediate temperatures (900C-1300C) -- II. dissociation and stacking faults
Sapphire and rubies (undoped and Cr-doped -AlO single
crystals) have been deformed in compression at temperatures lower than those
previously used in studies of dislocations in the basal slip plane (see part
I). Above 1400C, several features associating stacking faults out of
the basal planes and partial dislocations (dissociation, faulted dipoles) have
been observed in previous transmission electron microscope investigations. The
formation of these features involves climb controlled by atomic diffusion.
Properties of climb dissociated dislocations are discussed in relation with
dislocation dynamics. TEM examination of dislocation structures at lower
deformation temperatures (1000-1100C) shows that similar features are
formed but that they often imply cross-slip. A new mechanism for the formation
of faulted dipole by glide is presented and an explanation for the 30{\deg}
Peierls valley orientation is proposed. The presence of chromium has a small
influence on stacking fault energies on planes perpendicular to the basal
plane
Overview of ASDEX Upgrade results
The ASDEX Upgrade (AUG) programme is directed towards physics input to critical
elements of the ITER design and the preparation of ITER operation, as well as addressing
physics issues for a future DEMO design. Since 2015, AUG is equipped with a new pair of
3-strap ICRF antennas, which were designed for a reduction of tungsten release during ICRF
operation. As predicted, a factor two reduction on the ICRF-induced W plasma content could
be achieved by the reduction of the sheath voltage at the antenna limiters via the compensation
of the image currents of the central and side straps in the antenna frame. There are two main
operational scenario lines in AUG. Experiments with low collisionality, which comprise
current drive, ELM mitigation/suppression and fast ion physics, are mainly done with freshly
boronized walls to reduce the tungsten influx at these high edge temperature conditions. Full
ELM suppression and non-inductive operation up to a plasma current of Ip = 0.8 MA could
be obtained at low plasma density. Plasma exhaust is studied under conditions of high neutral
divertor pressure and separatrix electron density, where a fresh boronization is not required.
Substantial progress could be achieved for the understanding of the confinement degradation
by strong D puffing and the improvement with nitrogen or carbon seeding. Inward/outward
shifts of the electron density profile relative to the temperature profile effect the edge stability
via the pressure profile changes and lead to improved/decreased pedestal performance.
Seeding and D gas puffing are found to effect the core fueling via changes in a region of high
density on the high field side (HFSHD).
The integration of all above mentioned operational scenarios will be feasible and
naturally obtained in a large device where the edge is more opaque for neutrals and higher
plasma temperatures provide a lower collisionality. The combination of exhaust control
with pellet fueling has been successfully demonstrated. High divertor enrichment values of
nitrogen EN 10 have been obtained during pellet injection, which is a prerequisite for the
simultaneous achievement of good core plasma purity and high divertor radiation levels.
Impurity accumulation observed in the all-metal AUG device caused by the strong neoclassical
inward transport of tungsten in the pedestal is expected to be relieved by the higher
neoclassical temperature screening in larger devices.European Commission (EUROfusion 633053
Concentración de nutrientes en la escorrentía de diferentes predios del trópico enmendados con residuos animales bajo condiciones de lluvia natural.
Excessive nutrient losses from agricultural soils represent a major source of surface water contamination. In this study we quantified concentrations of total Kjeldahl nitrogen (TKN), dissolved and total phosphorus (DP,TP), and dissolved organic carbon (DOC) in runoff from two animal farm operations of Puerto Rico. The farms, one dairy and one poultry, represented typical conditions (i.e., topography, ecological zone, management system) of these production systems.Two fields were selected for the runoff studies on each farm, and two runoff collectors were installed in each field. Runoff samples were collected under natural rainfall conditions. The average phosphorus concentration in runoff from the poultry fields (5.87 mg TP/L, 4.82 mg DP/L) was significantly greater than that observed from the dairy fields (2.29 mg TP/L, 1.79 mg DP/L). Dissolved phosphorus concentrations represented more than 90% of the total P concentrations on both farms, a situation that may exacerbate the impact on receiving water bodies. Average DP concentrations exceeded 1 mg/L, a limit proposed for the regulation of runoff P concentrations from agricultural lands, in 70% of the runoff events at the dairy farm, and 100% of the events at the poultry farm. The magnitude of the nutrient concentrations on both farms was significantly affected by the time lapse between the manure applications and the first precipitation event. Nutrient concentrations in runoff samples were also significantly affected by rainfall depth.La pérdida excesiva de nutrientes de suelos agrícolas representa una fuente primaria de contaminación de los cuerpos de agua. En este estudio se cuantificaron las concentraciones de nitrógeno total Kjeldahl (NTK), fósforo total y disuelto (PD, PT), y carbón orgánico disuelto (COD) en la escorrentía de dos fincas productoras de animales de Puerto Rico. Las fincas, una vaquería y una avícola, son representativas de las condiciones típicas (i.e., topografía, zona ecológica, sistema de manejo) de estos sistemas de producción. En cada finca se seleccionaron dos predios para estudios de escorrentía y en cada predio se instalaron dos fraccionadores de escorrentía. Se recolectaron muestras de escorrentía generadas por eventos de lluvia natural. La concentración promedio de fósforo en la escorrentía de los predios avícolas (5.87 mg TP/L, 4.82 mg PD/L) fue significativamente mayor que la observada en los predios de la vaquería (2.29 mg PT/L, 1.79 mg PD/L). La concentración de PD representó cerca del 90% de la concentración de PT observada en ambas fincas, situación que puede agravar el impacto en las aguas circundantes. La concentración de PD promedio excedió 1 mg/L, límite propuesto para controlar la escorrentía de fósforo de predios agrícolas, en 70% de los eventos de escorrentía en el caso de la vaquería y en un 100% de los casos en la finca avícola. La magnitud de las concentraciones en ambas fincas se afectó significativamente por el lapso de tiempo transcurrido entre la aplicación de los residuos orgánicos y el primer evento de lluvia. La concentración de nutrientes en la escorrentía también se afectó significativamente con la profundidad de la lámina de lluvia
High-pressure tuning of d-d crystal-field electronic transitions and electronic band gap in Co(I O3)2
High-pressure optical-absorption measurements performed on polycrystalline
Co
(
I
O
3
)
2
samples were used to characterize the influence of pressure on the electronic
d
–
d
transitions associated with
Co
2
+
and the fundamental band gap of
Co
(
I
O
3
)
2
. The results shed light on the electron-lattice coupling and show that
Co
(
I
O
3
)
2
exhibits an unusual behavior because the compression of Co–O bond distances is not coupled to pressure-induced changes induced in the unit-cell volume. Experimental results on the internal
d
–
d
transitions of
Co
2
+
have been explained based on changes in the constituent
Co
O
6
octahedral units using the semiempirical Tanabe-Sugano diagram. Our findings support that the high-spin ground state
(
4
T
1
)
is very stable in
Co
(
I
O
3
)
2
. We have also determined the band-gap energy of
Co
(
I
O
3
)
2
and its pressure dependence which is highly nonlinear. According to density-functional theory band-structure calculations, this nonlinearity occurs because the bottom of the conduction band is dominated by I-5p orbitals and the top of the valence band by Co-3d and O-2p orbitals, and because the Co–O and I–O bond lengths exhibit different pressure dependences.This work was supported by the Generalitat Valenciana under Project No. PROMETEO 2018/123-EFIMAT and by the Spanish Research Agency (AEI) and Spanish Ministry of Science and Investigation (MCIN) under Projects No. PID2019106383GB-C41/C43 (DOI: 10.13039/501100011033) cofinanced by EU FEDER funds, No. PGC2018-101464-B-I00, and No. RED2018-102612-T. A.L. and D.E. thank the Generalitat Valenciana for the Ph.D. Fellowship No. GRISOLIAP/2019/025. R.T. acknowledges funding from the Spanish MINECO via the Juan de la Cierva Formación program (Grant No. FJC2018-036185-I).
Osteoartropatía hipertrófica pulmonar asociada a megaesófago en un perro
La osteoartropatía hipertrófica pulmonar (OHP) es una enfermedad de escasa presentación en la clínica rutinaria canina, secundaria a patologías intratorácicas crónicas, con lesiones que ocupan un cierto volumen intratorácico (neoplasias, abscesos, etc.), y que se caracteriza por la presencia de neoformaciones óseas en el periostio de los huesos de las extremidades. En el presente artículo se describe un caso clínico de osteoartropatía hipertrófica pulmonar (clínica, radiología, analítica sanguínea y urinaria, necropsia y estudios histopatológicos), asociada a un megaesófago, condición no descrita en la bibliografía consultada sobre la OHP canina.Hypertrophic pulmonary osteoarthropathy (HPO) is a rare clinical disease in the dog, secondary to spaceoccuping masses inside the thoracic cavity (neoplasms, abcesses, etc.) and it's characterized by neoformation of periosteal bone affecting mainly the distallimbs. The authors review the physiopathology of the disease and describe one clinical case of hypertrophic pulmonary osteoarthropathy (clinical state, radiology, blood and urine analysis, necropsy results and histologic conclusions) associated with megaesofagus, condition not yet described associated to HPO
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