Radiative corrections to the polarizability tensor of an electrically small anisotropic dielectric particle

Radiative corrections to the polarizability tensor of isotropic particles are fundamental to understand the energy balance between absorption and scattering processes. Equivalent radiative corrections for anisotropic particles are not well known. Assuming that the polarization within the particle is uniform, we derived a closed-form expression for the polarizability tensor which includes radiative corrections. In the absence of absorption, this expression of the polarizability tensor is consistent with the optical theorem. An analogous result for infinitely long cylinders was also derived. Magneto optical Kerr effects in non-absorbing nanoparticles with magneto-optical activity arise as a consequence of radiative corrections to the electrostatic polarizability tensor.This work has been supported by the EU NMP3-SL-2008-214107-Nanomagma, the Spanish MICINN Consolider NanoLight (CSD2007-00046), FIS2006-11170-C02-02 and by the Comunidad de Madrid Microseres-CM Program. R.G.-M. acknowledges support from the EU COST-MP0803. Work by R.G.-M. and L.S.F.-P. was supported by the MICINN “Juan de la Cierva” Program.Peer reviewe

Conductance Fluctuations in Disordered Wires with Perfectly Conducting Channels

We study conductance fluctuations in disordered quantum wires with unitary symmetry focusing on the case in which the number of conducting channels in one propagating direction is not equal to that in the opposite direction. We consider disordered wires with $N+m$ left-moving channels and $N$ right-moving channels. In this case, $m$ left-moving channels become perfectly conducting, and the dimensionless conductance $g$ for the left-moving channels behaves as $g \to m$ in the long-wire limit. We obtain the variance of $g$ in the diffusive regime by using the Dorokhov-Mello-Pereyra-Kumar equation for transmission eigenvalues. It is shown that the universality of conductance fluctuations breaks down for $m \neq 0$ unless $N$ is very large.Comment: 6 pages, 2 figure

Optical parametric oscillation with distributed feedback in cold atoms

There is currently a strong interest in mirrorless lasing systems, in which the electromagnetic feedback is provided either by disorder (multiple scattering in the gain medium) or by order (multiple Bragg reflection). These mechanisms correspond, respectively, to random lasers and photonic crystal lasers. The crossover regime between order and disorder, or correlated disorder, has also been investigated with some success. Here, we report one-dimensional photonic-crystal lasing (that is, distributed feedback lasing) with a cold atom cloud that simultaneously provides both gain and feedback. The atoms are trapped in a one-dimensional lattice, producing a density modulation that creates a strong Bragg reflection with a small angle of incidence. Pumping the atoms with auxiliary beams induces four-wave mixing, which provides parametric gain. The combination of both ingredients generates a mirrorless parametric oscillation with a conical output emission, the apex angle of which is tunable with the lattice periodicity

Conductance Distribution in Disordered Quantum Wires with a Perfectly Conducting Channel

We study the conductance of phase-coherent disordered quantum wires focusing on the case in which the number of conducting channels is imbalanced between two propagating directions. If the number of channels in one direction is by one greater than that in the opposite direction, one perfectly conducting channel without backscattering is stabilized regardless of wire length. Consequently, the dimensionless conductance does not vanish but converges to unity in the long-wire limit, indicating the absence of Anderson localization. To observe the influence of a perfectly conducting channel, we numerically obtain the distribution of conductance in both cases with and without a perfectly conducting channel. We show that the characteristic form of the distribution is notably modified in the presence of a perfectly conducting channel.Comment: 7 pages, 16 figure

Freshwater conservation assessments in (semi-)arid regions: testing river intermittence and buffer strategies using freshwater mussels (Bivalvia, Unionida) in Morocco

The IUCN Red List assessments are essentially based on population trends and range, namely Area of Occupancy (AOO) and Extent of Occupancy (EOO). Range estimations are based on fixed grids, but this is likely inappropriate for species living in river networks. Furthermore, AOO and EOO are measured using the whole hydrographic network, therefore disregarding temporary sections, which is particularly problematic in arid and semi-arid regions. Here we mapped the permanent hydrographic network of Morocco using satellite imagery, complemented with field surveys to collect samples for molecular analyses of the five freshwater mussel species present and assess their distribution. The phylogeographic patterns are described for each species and used to identify priority areas and evolutionary significant units for conservation. Permanent hydrographic river sections represent only 18.3% of the whole hydrographic network. A north-to-south gradient of genetic diversity, species richness and distribution range was found, being coherent with water availability and river intermittence. Isolated evolutionary units were detected in southern basins that should also receive particular attention in conservation planning. We propose the mean river width multiplied by the extent of the river network as the best and the most adequate way to estimate both EOO and AOO. Given the worldwide degradation of freshwater systems and biodiversity, an accurate (re)assessment of species conservation status supported with maps of intermittent water bodies will be essential for prioritizing and guiding conservation actions and management plans, especially in arid and semi-arid regions.This work was partially supported by the Portuguese Foundation for Science and Technology (FCT) under grant SFRH/BD/115728/2016 (MLL) and grant SFRH/BD/137935/2018 (AGS). This research was developed under ConBiomics: the missing approach for the Conservation of freshwater Bivalves Project N° NORTE-01-0145-FEDER-030286, co-financed by COMPETE 2020, Portugal 2020 and the European Union through the ERDF, and by FCT through national funds. This study was additionally conducted within the scope of project “Biodiversity and conservation of the critically endangered freshwater mussels in Morocco: ecogeographic, genetic and physiological information”, funded by Mohamed bin Zayed Species Conservation Fund (Reference 15256799) and project “Breeding the most endangered bivalve on Earth: Margaritifera marocana”, funded by IUCN SOS save our species fund (Reference 2015B-015). Official capture and sampling licenses were issued by the Université Cadi Ayyad (Faculté des Sciences, Semlalia, Marrakech, Maroc)

The random phase property and the Lyapunov Spectrum for disordered multi-channel systems

A random phase property establishing in the weak coupling limit a link between quasi-one-dimensional random Schrödinger operators and full random matrix theory is advocated. Briefly summarized it states that the random transfer matrices placed into a normal system of coordinates act on the isotropic frames and lead to a Markov process with a unique invariant measure which is of geometric nature. On the elliptic part of the transfer matrices, this measure is invariant under the unitaries in the hermitian symplectic group of the universality class under study. While the random phase property can up to now only be proved in special models or in a restricted sense, we provide strong numerical evidence that it holds in the Anderson model of localization. A main outcome of the random phase property is a perturbative calculation of the Lyapunov exponents which shows that the Lyapunov spectrum is equidistant and that the localization lengths for large systems in the unitary, orthogonal and symplectic ensemble differ by a factor 2 each. In an Anderson-Ando model on a tubular geometry with magnetic field and spin-orbit coupling, the normal system of coordinates is calculated and this is used to derive explicit energy dependent formulas for the Lyapunov spectrum

Synthesis, antiangiogenesis evaluation and molecular docking studies of 1-Aryl-3-[(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas: Discovery of a new substitution pattern for type II VEGFR-2 Tyr kinase inhibitors

The synthesis and biological evaluation of novel 1-aryl-3-[2-, 3- or 4-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 3, 4 and 5 as VEGFR-2 tyrosine kinase inhibitors, are reported. The 1-aryl-3-[3-(thieno[3,2-b]pyridin-7-ylthio)phenyl]ureas 4a-4h, with the arylurea in the meta position to the thioether, showed the lowest IC50 values in enzymatic assays (10-206 nM), the most potent compounds 4d-4h (IC50 10-28 nM) bearing hydrophobic groups (Me, F, CF3 and Cl) in the terminal phenyl ring. A convincing rationalization was achieved for the highest potent compounds 4 as type II VEGFR-2 inhibitors, based on the simultaneous presence of: (1) the thioether linker and (2) the arylurea moiety in the meta position. For compounds 4, significant inhibition of Human Umbilical Vein Endothelial Cells (HUVECs) proliferation (BrdU assay), migration (wound-healing assay) and tube formation were observed at low concentrations. These compounds have also shown to increase apoptosis using the TUNEL assay. Immunostaining for total and phosphorylated (active) VEGFR-2 was performed by Western blotting. The phosphorylation of the receptor was significantly inhibited at 1.0 and 2.5 microM for the most promising compounds. Altogether, these findings point to an antiangiogenic effect in HUVECs.To the Foundation for Science and Technology (FCT–Portugal) for financial support through the NMR Portuguese network (Bruker 400 Avance III-Univ Minho). FCT and FEDER (European Fund for Regional Development)-COMPETE/QREN/EU for financial support through the research unities PEst-C/QUI/UI686/2013-2014, PEst-OE/SAU/UI0038/2013 and 2014 and PEst OE/AGR/UI0690/2013 and 2014, the research project PTDC/QUI-QUI/111060/2009, the PhD grant attributed to V.M. (SFRH/BD/77373/2011) and the post-Doctoral grant attributed to R.C.C. (SFRH/BPD/68344/2010), also financed by the POPH and FSE

Feiras livres como alternativa de comercialização de produtos da agrofloresta.

Com a busca por alternativas comerciais socialmente justas como maneira de otimizar a comercialização de produtos provenientes de agricultura familiar, destaca se a venda direta através de feiras, livres, que permite acesso direto ao consumidor sem necessidade de intermediadores. O Grupo de Produtores Agroflorestais Gralha Azul, de Morretes-PR, iniciou plantios de agroflorestas agroecológicas em 2009, sendo formado, atualmente, por 12 famílias de agricultores. Há um ano, o Gralha Azul iniciou sua participação na Matinfeira, feira semanal de produtos da agricultura familiar em Matinhos, PR. Com o objetivo de caracterização dos produtos, produtores e do processo de comercialização, foram acompanhados e sistematizados em planilha a comercialização destes produtos em 22 feiras semanais, entre maio e dezembro de 2012. Onze produtores participaram da Matinfeira, comercializando entre 13 e 29 variedades de alimentos, e proporcionando uma renda que variou de R$101,00 a R$ 386,50, por semana. Mensalmente, as feiras permitiram uma receita bruta de R$ 141,17 por produtor familiar agroflorestal. Apesar desse baixo valor, há que se considerar que o mesmo reflete os primeiros seis meses de atuação do Grupo no processo de comercialização na feira (Matinfeira). A venda direta através desta feira livre mostra potencial como alternativa comercial socialmente justa para os produtores em transição agroecológica do Grupo Gralha Azul

Cardiospondylocarpofacial syndrome as a distinct hereditary connective tissue disorder: novel missense variant in MAP3K7 in two unrelated patients

CDKL5 deficiency disorder is a rare X-linked condition that results in early onset of impairedmotor and cognitive skills such as motor rigidity, stereotypical hand movements and deficient language acquisition aswell as recurrent seizures. It is caused by mutations in the cyclin-dependent kinase-like 5 (CDKL5) gene, which encodes a serine/threonine kinase involved in important neuronal processes such as cell signaling and neuron morphogenesis.FCT: UID/Multi/04326/2019 (CCMAR)info:eu-repo/semantics/publishedVersio