2,347 research outputs found

    Full-wave electromagnetic modes and hybridization in nanoparticle dimers

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    The plasmon hybridization theory is based on a quasi-electrostatic approximation of the Maxwell’s equations. It does not take into account magnetic interactions, retardation effects, and radiation losses. Magnetic interactions play a dominant role in the scattering from dielectric nanoparticles. The retardation effects play a fundamental role in the coupling of the modes with the incident radiation and in determining their radiative strength; their exclusion may lead to erroneous predictions of the excited modes and of the scattered power spectra. Radiation losses may lead to a significant broadening of the scattering resonances. We propose a hybridization theory for non-Hermitian composite systems based on the full-Maxwell equations that, overcoming all the limitations of the plasmon hybridization theory, unlocks the description of dielectric dimers. As an example, we decompose the scattered field from silicon and silver dimers, under different excitation conditions and gap-sizes, in terms of dimer modes, pinpointing the hybridizing isolated-sphere modes behind them

    Automatic optimization of software data planes

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    Participatory mapping of livestock routes in Samburu county, Kenya

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    Lectin-binding sites in the seminal vesicles of entire and castrated horses

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    This research was undertaken to determine the glycoconjugates secreted by the glandular epithelium of the seminal vesicles in the entire and castrated horses using lectin histochemistry in combination with sialidase digestion and deglycosylation pre-treatments. The following lectins were used: Con-A, UEA-I, LTA, WGA, GSA-IB4, SBA, PNA, ECA and DBA. In the entire stallion, the glandular cells expressed the following sugar residues: a-Fuc, internal GlcNAc, terminal b- and a-GalNAc, b-D-Gal-(1-4)-GlcNAc and a-Gal included in O-linked oligosaccharides; b-Gal-(1-3)-GalNAc belonged to both O- and N-oligosaccharides whereas terminal GlcNAc to N-linked glycans. Additionally, a-Gal and b-Gal acted as acceptor sugars for sialic acid moieties. In castrated horses, the glandular epithelium showed a different lectin labelling pattern. In particular, we evidenced internal GlcNAc, a-GalNAc, b-Gal-(1-3)-GalNAc in both O- and N-linked glycoproteins whereas b-GalNAc and b-Gal-(1-3)-GalNAc in O-linked glycoproteins. The differences evidenced in the lectin profile between the stallion and castrated horse suggested an hormonal regulation of the glycoconjugate production. Additionally, the plurality of glycomolecules detected in the secretions of the stallion may be involved in spermatozoa maturatio

    Lagrangian Variational Framework for Boundary Value Problems

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    A boundary value problem is commonly associated with constraints imposed on a system at its boundary. We advance here an alternative point of view treating the system as interacting "boundary" and "interior" subsystems. This view is implemented through a Lagrangian framework that allows to account for (i) a variety of forces including dissipative acting at the boundary; (ii) a multitude of features of interactions between the boundary and the interior fields when the boundary fields may differ from the boundary limit of the interior fields; (iii) detailed pictures of the energy distribution and its flow; (iv) linear and nonlinear effects. We provide a number of elucidating examples of the structured boundary and its interactions with the system interior. We also show that the proposed approach covers the well known boundary value problems.Comment: 41 pages, 3 figure

    Efficient time-domain simulation of lossy multiconductor transmission lines by means of generalized method of characteristics

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    Abstract The paper investigates some crucial aspects in the derivation of time-domain equivalent circuits of lossy multiconductor transmission lines, obtained by using the generalized method of characteristic. The paper highlights how an exact evaluation of the effect of the propagation delays not only provide an accurate time-domain equivalent circuit, but suggests naturally the way to obtain a reduced-order model. The propagation is described correctly by means of damped delayed sources, while the effects of losses are efficiently taken into account by a low-order approximated lumped circuit. In this way it is easy to circumvent the main problems arising when using the generalized method of characteristic that is the correct evaluation of the impulse responses describing the time-domain model and the computational cost of the time-domain convolutions

    Production of Giant \u3cem\u3ePanicum\u3c/em\u3e in Contrasting Environments in Semi-Arid Kenya

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    Giant panicum (Panicum maximum Jacq.) is a tall, vigorous perennial grass that is native to tropical and sub-tropical Africa. It is drought tolerant due to its deep and dense fibrous roots system and grows in a wide range of soil types. It is an important livestock feed and has been extensively cultivated in Brazil (Santos et al. 2006). Despite its wide genetic diversity in East Africa, its potential for livestock feed has not been exploited there due to limited research. Our research was aimed at evaluating the production of several giant panicum ecotypes in contrasting environments in semi-arid areas of Kenya

    Ablation of smooth muscle myosin heavy chain SM2 increases smooth muscle contractility and results in postnatal death in mice

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    The smooth muscle myosin heavy chains (SMHC) are motor proteins powering smooth muscle contraction. Alternate splicing of SHMC gene at the C-terminus produces SM1, and SM2 myosin isoforms; SM2 (200 kDa) contains a unique 9-amino-acid sequence at the carboxyl terminus, whereas SM1 (204 kDa) has a 43 amino acid non-helical tail region. To date the functional difference between C-terminal isoforms has not been established; therefore, we used an exon-specific gene targeting strategy and generated a mouse model specifically deficient in SM2. Deletion of exon-41 of the SMHC gene resulted in a complete loss of SM2 in homozygous (_SM2^-/-^_) mice, accompanied by a concomitant down-regulation of SM1 in bladders. While heterozygous (_SM2^+/-^_) mice appeared normal and fertile, _SM2^-/-^_ mice died within 30 days after birth. The peri-mortal _SM2^-/-^_ mice showed reduced body weight, distention of the bladder and alimentary tract, and end-stage hydronephrosis. Interestingly, strips from _SM2^-/-^_ bladders showed increased contraction to K^+^ depolarization or M3 receptor activation. These results suggest that SM2 myosin has a distinct functional role in smooth muscle, and the deficiency of SM2 increases smooth muscle contractility, and causes dysfunctions of smooth muscle organs, including the bladder that leads to the end-stage hydronephrosis and postnatal death
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