203 research outputs found

    Control of the Light Interaction in a Semiconductor Nanoparticle Dimer Through Scattering Directionality

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    11 págs.; 4 figs.; 1 tab.Dimers of nanoparticles are very interesting for several devices due to the possibility of obtaining intense light concentrations in the gap between them. A dynamic control of this interaction to obtain either the maximum or minimum light through interferential effects could be also relevant for a multitude of devices such as chemical sensors or all-optical devices for interchip/intrachip communications. Semiconductor nanoparticles satisfying Kerker conditions present an anisotropic scattering distribution with a minimum in either the forward or the backward direction and prominent scattering in the contrary direction. The reduction or enhancement of the electromagnetic field in a certain direction can minimize or maximize the interaction with neighboring nanoparticles. In this paper, we consider a dimer of nanoparticles such that each component satisfies each one of the Kerker conditions. Depending on the arrangement of the nanoparticles with respect to the impinging light direction, we can produce a minimum or a maximum of the electric field between them, reducing or maximizing the interferential effects. The strong dependence of the directional conditions with external conditions, such as the incident wavelength, can be used to dynamically control the light concentration in the gap. Ó 2016 IEEEThis work was supported in part by the Ministerio de Economía y Competitividad of Spain under Grant TEC2013—50138—EXP and Grant TEC2013-47342-C2-2-R, by the RD Program of the Comunidad de Madrid under Grant SINFOTON S2013/MIT—2790, and by COST Action IC1208.Peer Reviewe

    Effect of soybean meals of different origins on apparent ileal digestibility of amino acids in 22-day-old broilers

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    We studied the effect of soybean meals (SBM) from USA, Brazil (BRA), and Argentina (ARG) on the apparent ileal digestibility (AID) of the amino acids (AA) . In total, 500 one-day-old, straight run Ross 308 broilers were used. Nine SBM samples from 3 different origins, USA (n = 3), Brazil (BRA; n = 3), and Argentina (ARG; n = 3) were used in the study

    Influence of body weight at hatching and inclusion of oat hulls in the diet on growth performance and digestive tract traits of brown-egg laying pullets from 0 to 16 wk of age

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    The influence of pre-incubated weight of eggs (EW) laid by 24 wk-old brown layer breeders and the inclusion (wt:wt) of 3% oat hulls (OH) in the diet on growth performance and gastrointestinal tract (GIT) traits were studied in pullets reared under stressful conditions from hatching to 16 wk of age. The initial BW of the pullets resulting from these eggs was of 29.9 and 38.2 g for the 2 extreme groups. The stress applied consisted in using a prolonged (8 h) transport time from the hatchery to the experimental facility, reducing barn temperature at night from placement to 7 d of age, and late beak trimming of the pullets (18 d). Growth performance, pullet uniformity, and GIT traits were measured by period (0 to 5 wk, 5 to 10 wk, and 10 to 16 wk of age) and cumulatively. Data were analyzed as a completely randomized design with treatments organized as a 7 × 2 factorial, with 7 groups of pullets that differed on pre-hatched EW (47 to 54 g with 1 g difference between groups) and 2 levels of OH inclusion (0 vs. 3%). Effects of EW on the variables studied were partitioned into linear and quadratic components. The stress conditions applied affected pullet growth, with BW at 5 wk of age that were as an average 27% lower than recommended by the genetic company (269 g vs. 367 g). Neither initial EW nor OH inclusion affected any of the variables studied. In summary, EW of young breeders did not affect growth performance, BW uniformity, or GIT traits of the resulting pullets from 0 to 16 wk of age. Eggs bigger than 47 g laid by young breeders can produce high quality pullets. Pullets fed diets with 3% OH performed equally to pullets fed the control diet, suggesting that the amount of fiber can be increased during the rearing period of brown egg pullet

    D-brane instantons and the effective field theory of flux compactifications

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    We provide a description of the effects of fluxes on euclidean D-brane instantons purely in terms of the 4d effective action. The effect corresponds to the dressing of the effective non-perturbative 4d effective vertex with 4d flux superpotential interactions, generated when the moduli fields made massive by the flux are integrated out. The description in terms of effective field theory allows a unified description of non-perturbative effects in all flux compactifications of a given underlying fluxless model, globally in the moduli space of the latter. It also allows us to describe explicitly the effects on D-brane instantons of fluxes with no microscopic description, like non-geometric fluxes. At the more formal level, the description has interesting connections with the bulk-boundary map of open-closed two-dimensional topological string theory, and with the \NN=1 special geometry.Comment: 33 page

    Effect of a serine protease on the energy content of soybean meals of different origins in 22-d-old broilers

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    A total of 1,152 one-day-old straight-run Ross 308 broilers were used to study the effect of using a mono component serine protease (PRO; Ronozyme ProAct, DSM Nutritional Products) on the AMEn of soybean meals (SBM) from USA, Brazil (BRA), and Argentina (ARG). The design was a 3 × 2 factorial arrangement of 3 SBM of different origin (USA, BRA, and ARG) and 2 levels of PRO (0 and 200 mg/kg to give 0 to 15,000 PROT units/kg feed) resulting in 6 treatments. Each of the 6 treatments was replicated 24 times and the experimental unit was a cage with 8 broilers. Birds were fed a commercial corn-soybean meal diet from 1 to 18 d of age followed by the experimental diets that resulted from the combination of 42.6% SBM and 57.4% of a nitrogen free diet to 22 d of age. The AMEn of the diet was 1.4% and 3.8% higher in chicks fed USA SBM than in chicks fed BRA or ARG SBM (2,921 vs. 2,880 vs. 2,814 kcal/kg, respectively; P < 0.001). PRO supplementation increased the AMEn of the diet by an average of 1.1% (2,888 vs. 2,856 kcal/kg; P < 0.001). An interaction between SBM origin and protease supplementation was detected (P < 0.01); addition of PRO increased AMEn diet with USA or ARG SBM but not those with BRA SBM. In conclusion, AMEn of the diet based on USA SBM was higher than that of diets with BRA SBM, and was lowest for diets with ARG SBM ARG meals. PRO supplementation increased the AMEn of diets, an improvement that varied depending on the origin of the SBM

    D terms from D-branes, gauge invariance and moduli stabilization in flux compactifications

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    We elucidate the structure of D terms in N=1 orientifold compactifications with fluxes. As a case study, we consider a simple orbifold of the type-IIA theory with D6-branes at angles, O6-planes and general NSNS, RR and Scherk-Schwarz geometrical fluxes. We examine in detail the emergence of D terms, in their standard supergravity form, from an appropriate limit of the D-brane action. We derive the consistency conditions on gauged symmetries and general fluxes coming from brane-localized Bianchi identities, and their relation with the Freed-Witten anomaly. We extend our results to other N=1 compactifications and to non-geometrical fluxes. Finally, we discuss the possible role of U(1) D terms in the stabilization of the untwisted moduli from the closed string sector.Comment: 1+31 pages, 1 figur

    No-scale supersymmetry breaking vacua and soft terms with torsion

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    We analyze the conditions to have no-scale supersymmetry breaking solutions of type IIA and IIB supergravity compactified on manifolds of SU(3)-structure. The supersymmetry is spontaneously broken by the intrinsic torsion of the internal space. For type IIB orientifolds with O9 and O5-planes the mass of the gravitino is governed by the torsion class W_1, and the breaking is mediated through F-terms associated to descendants of the original N=2 hypermultiplets. For type IIA orientifolds with O6-planes we find two families of solutions, depending on whether the breaking is mediated exclusively by hypermultiplets or by a mixture of hypermultiplets and vector multiplets, the latter case corresponding to a class of Scherk-Schwarz compactifications not dual to any geometric IIB setup. We compute the geometrically induced mu-terms for D5, D6 and D9-branes on twisted tori, and discuss the patterns of soft-terms which arise for pure moduli mediation in each type of breaking. As for D3 and D7-branes in presence of 3-form fluxes, the effective scalar potential turns out to possess interesting phenomenological properties.Comment: 44 pages; several minor corrections and added reference

    Holomorphic variables in magnetized brane models with continuous Wilson lines

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    We analyze the action of the target-space modular group in toroidal type IIB orientifold compactifications with magnetized D-branes and continuous Wilson lines. The transformation of matter fields agree with that of twisted fields in heterotic compactifications, constituting a check of type I/heterotic duality. We identify the holomorphic N = 1 variables for these compactifications. Matter fields and closed string moduli are both redefined by open string moduli. The redefinition of matter fields can be read directly from the perturbative Yukawa couplings, whereas closed string moduli redefinitions are obtained from D-brane instanton superpotential couplings. The resulting expressions reproduce and generalize, in the presence of internal magnetic fields, previous results in the literature.Comment: 9 pages, no figures; v2: conventions for Wilson lines changed, major simplifications in expressions, discussions extended, typos corrected, some references adde
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