Search results for "Trion"
showing 10 items of 92 documents
A finely tuned strategy adopted by an egg parasitoid to exploit chemical traces from host adults.
2009
SUMMARY Scelionid egg parasitoids can obtain reliable information on the presence of host eggs by discriminating host gender on the basis of chemical footprints of their co-evolved hosts, with a strong preference for the footprint left by host females. Based on the concept of dietary specialization and infochemical use in natural enemies, it could be predicted that host gender discrimination in specialist species belonging to the genus Trissolcus is further tuned to specific cues from distinctive chemical traces left by host females as a consequence of copulation and/or oviposition. To test this hypothesis we used the system Murgantia histrionica – Trissolcus brochymenae. Our results showed…
Michele Cometa, Il Trionfo della Morte. Un’allegoria della modernità
2018
La lettura del libro di Michele Cometa sull'affresco il Trionfo della Morte, esposto presso la Galleria Regionale di Palazzo Abatellis di Palermo, è affrontata attraverso l'individuazione di due sentieri di indaginedue sentieri solo apparentemente paralleli. Quali sono le due piste? Una è dedicata all’Ékphrasis, cioè alla descrizione delle immagini; l’altra alla fine, alla conclusione, alla morte. Questi due itinerari trovano nella dimensione del tempo, o se si vuole nella sua negazione, l’humus comune. L’affresco realizzato per l’Ospedale nuovo di Palazzo Sclafani occupa, dai primi anni Cinquanta del XX secolo, la parete di fondo della chiesa di Santa Maria della Pietà annessa a palazzo Ab…
Une histoire de l'élevage : les animaux et l'Archéologie
1987
Ouvrage de vulgarisation
Impact of heteroptera pentatomidae feeding and oviposition on photosynthesis of herbaceous plants and egg parasitoids host location
2009
The present study was designed to examine the effect of heteroptera pentatomidae feeding and/or oviposition on photosynthesis. Murgantia histrionica and Nezara viridula were fed on Brassica and Phaseolus plants, respectively. The changes in photosynthetic gas exchange and chlorophyll fluorescence parameters were followed immediately after the feeding as well as during the post-feeding period (24, 48 and 72 h). Murgantia feeding caused visible damage on leaf lamina, whereas this was not the case with Nezara feeding. In both cases a substantial decrease (50%) in photosynthesis was observed, which was partially restored only in Phaseolus plants by the end of the experiment. By using high resol…
The holocene marine depositional event in the historical centre of palermo
2004
Studi recenti hanno indicato come al di sopra della classica sequenza del Quaternario marino della Piana di Palermo ricorra, in alcunisiti del Centro Storico, un limitato spessore di depositi marini di età post-tirreniana. Con lo scopo di precisare l’età di tali depositi sonostate studiate le associazioni di microfossili di campioni provenienti da sondaggi geognostici. Utilizzando lo schema ecobiozonale anannofossili calcarei recentemente proposto per l’ultima deglaciazione nel Mediterraneo centrale (Canale di Sicilia) detti depositi contengononannoflore attribuibili all’Olocene. Un'analisi al radiocarbonio ha confermato tale attribuzione, limitando alla parte bassadell'Olocene la pertinenz…
Charge control in laterally coupled double quantum dots
2011
4 figuras, 4 páginas.-- PACS number(s): 78.67.Hc, 73.21.La, 78.55.Cr
Exciton, biexciton and trion recombination dynamics in a single quantum dot under selective optical pumping
2008
Continuous wave- and time-resolved micro-photoluminescence spectroscopy has been performed on single InAs self-assembled quantum dots grown on GaAs. The presence of residual impurities (donors and acceptors) in samples with low dot density opens the possibility to switch from trion to neutral exciton states inside quantum dots by selective optical pumping. We propose a microstate model to describe the recombination dynamics of all the excitonic especies (neutral exciton, positive/negative trion and biexciton) under the considered optical pumping conditions when increasing the excitation power. © 2007 Elsevier B.V. All rights reserved.
Photoluminescence structure of highly excited quantum dots of type II
2007
Abstract The photoluminescence (PL) due to decay of exciton-like e–e–h complex X– (expected to appear for higher levels of activation) in electrically defined quantum dots of type II is analyzed within the Hartree approach for Gaussian confining potential, where the existence of metastable (against far-infrared interband dipole transitions) states is predicted, due to interplay of bare confinement with Coulomb interaction between the carriers. As we will show, when three-particle complexes (e–e–h) are taken into account, three PL peaks can occur at zero magnetic field, which further split into four peaks when external magnetic field is applied, which stands in a good correspondence with the…
Tuning the exciton luminescence in an acoustically depleted two-dimensional electron gas
2007
Standing-wave piezoelectric fields can be used to vary spatially and temporally charge conditions in $\mathrm{Ga}\mathrm{As}∕\mathrm{Al}\mathrm{Ga}\mathrm{As}$ quantum wells (QWs), offering a versatile tool to control the two-dimensional electron gas (2DEG) density in the well. A $\mathrm{Li}\mathrm{Nb}{\mathrm{O}}_{3}$ piezoelectric resonator imparts a MHz-frequency oscillating piezoelectric field with a controllable ratio of the in-plane and the vertical field components to a 2DEG placed in close proximity to the plate surface. This allows us to dynamically tune the charge state in the plane of the QW and to influence the photoluminescence spectra. It is found that spatially distributed r…
Psychological interventions for people with histrionic personality disorder
2012
Reason for withdrawal from publication Authors have made no progress with this protocol in over a year due to difficulties with identifying potentially suitable studies. The protocol has been withdrawn. To view the published versions of this article, please click the 'Other versions' tab.