Eye-movements reveal semantic interference effects during the encoding of naturalistic scenes in long-term memory

Similarity-based semantic interference (SI) hinders memory recognition. Within long-term visual memory paradigms, the more scenes (or objects) from the same semantic category are viewed, the harder it is to recognize each individual instance. A growing body of evidence shows that overt attention is intimately linked to memory. However, it is yet to be understood whether SI mediates overt attention during scene encoding, and so explain its detrimental impact on recognition memory. In the current experiment, participants watched 372 photographs belonging to different semantic categories (e.g., a kitchen) with different frequency (4, 20, 40 or 60 images), while being eye-tracked. After 10 minutes, they were presented with the same 372 photographs plus 372 new photographs and asked whether they recognized (or not) each photo (i.e., old/new paradigm). We found that the more the SI, the poorer the recognition performance, especially for old scenes of which memory representations existed. Scenes more widely explored were better recognized, but for increasing SI, participants focused on more local regions of the scene in search for its potentially distinctive details. Attending to the centre of the display, or to scene regions rich in low-level saliency was detrimental to recognition accuracy, and as SI increased participants were more likely to rely on visual saliency. The complexity of maintaining faithful memory representations for increasing SI also manifested in longer fixation durations; in fact, a more successful encoding was also associated with shorter fixations. Our study highlights the interdependence between attention and memory during high-level processing of semantic information

Estabelecimento in vitro de pimenta de macaco utilizando sementes.

A pimenta de macaco (Piper aduncum L.) é um arbusto nativo da América Tropical, cujo óleo essencial apresenta elevado teor de dilapiol, utilizado como fungicida e inseticida. Este trabalho teve como objetivo estudar a germinação de sementes de pimenta de macaco in vitro sob influência da sua disposição e diferentes concentrações de ácido giberélico, com incidência e ausência de luz. Foram instalados dois experimentos equivalentes e em paralelo, diferindo apenas quanto à luminosidade, sendo um com 16 horas de luz e o outro no escuro contínuo. O delineamento experimental foi o inteiramente casualizado, sendo avaliadas seis concentrações de AG3 (0; 0,5; 1,0; 1,5; 2,0 e 2,5 mg.L-1) e duas formas de disposição das sementes (isoladas e agrupadas), com 5 repetições, em meio de cultura MS. Após 45 dias foi avaliado a porcentagem de germinação, o índice de velocidade de germinação e as médias do número de folhas, do comprimento da parte aérea e da raiz. O estabelecimento in vitro de pimenta de macaco não é afetado pela condição de luminosidade. As concentrações 2,0 e 2,5 mg.L-1 AG3 no meio de cultura são as mais promissoras no estabelecimento in vitro desta espécie. As sementes quando dispostas em grupos apresentaram melhor resposta quanto ao comprimento da parte aera

Synthesis of 1-amino-4-(2´-thienyl)phthalazine derivatives

A synthesis of 1-amino substituted 4-(2´-thienyl)-phthalazines is described from halo- derivatives of 4-(2´-thienyl)-1-(2H)-phthalazinone 3.Fundação para a Ciência e Tecnologia. FEDER - POCTI (ref. POCTI/QUI/37816/2001)

Acoustic-roughness receptivity in subsonic boundary-layer flows over aerofoils

The generation of a viscous–inviscid instability through scattering of an acoustic wave by localised and distributed roughness on the upper surface of a NACA 0012 aerofoil is studied with a time-harmonic compressible adjoint linearised Navier–Stokes approach. This extends previous work by the authors dedicated to flat plate geometries. The key advancement lies in the modelling of the inviscid acoustic field external to the aerofoil boundary layer, requiring a numerical solution of the convected Helmholtz equation in a non-uniform inviscid field to determine the unsteady pressure field on the curved aerofoil surface. This externally imposed acoustic pressure field subsequently drives the acoustic boundary layer, which fundamentally determines the amplitudes of acoustic-roughness receptivity. A study of receptivity in the presence of Gaussian-shaped roughness and sinusoidally distributed roughness at Mach number M∞ = 0.4 and Strouhal numbers S ≈ {46, 69, 115} shows the effects of various parameters, most notably angle of attack, angle of incidence of the externally imposed plane acoustic wave and geometry of surface roughness; the latter is varied from viewpoint of its placement on the aerofoil surface and its wavelength. The parametric study suggests that non-parallel effects are quite substantial and that considerable differences arise when using parallel flow theory to estimate the optimal width of Gaussian-shaped roughness elements to provoke the greatest response. Furthermore, receptivity amplitudes for distributed roughness are observed to be generally higher for lower angles of attack, i.e. for less adverse pressure gradients. It is also shown that the boundary layer is more receptive to upstream-travelling acoustic waves

Synthesis of arylamino-thieno-oxobutanamides and reactivity studies on the cyclisation with the Lawesson´s reagent

1-aryl-2-thienyl-substituted pyrroles and 5-arylamino-2,2´-bithiophenes are synthesized by treatment of arylamino-thieno-oxobutanamides with Lawesson´s reagent. These in turn are prepared by direct amidation of 4-oxo-(2-thienyl)butanoic acid through DCC/BtOH mediated reaction.Fundação para a Ciência e Tecnologia. FEDER - POCTI/QUI/37816/2001

Donor-acceptor substituted oligothiophenes: synthesis, spectroscopic and electrochemical properties

Seven new donor/acceptor oligothiophenes 1-2 were synthesized by Stille coupling in moderate to good yields. Compounds 1-2 were completely characterized by the usual spectroscopic methods. In agreement with the electrochemical and the spectroscopic studies for this compounds the new derivatives prepared, can find application for manufacturing new materials with strong non-linear optical (NLO) properties.Fundação para a Ciência e a Tecnologia (FCT

Synthesis of donor-acceptor substituted oligothiophenes by Stille coupling

A synthesis of donor-acceptor-substituted oligothiophenes by Stille coupling is described. The 5´-estanyl derivatives, readily prepared from 5-alkoxy- and 5-amino-2,2´-bithiophenes 7 were coupled with the appropriate aryl or heteroaryl bromides to give the title compounds.Fundação para a Ciência e Tecnologia. FEDER - POCTI/QUI/37816/2001

Arylamino-thieno-oxobutanamides under Lawesson’s conditions : competition between thienylpyrrole and bithiophene formation

1-Aryl-2-thienyl-substituted pyrroles and/or 5-arylamino-2,2´-bithiophenes were synthesized by treatment of arylaminothieno-oxobutanamides with Lawesson’s reagent. These in turn were prepared by direct amidation of 4-oxo-(2-thienyl)butanoic acid through DCC–BtOH mediated reactions.Fundação para a Ciência e Tecnologia (FCT