1,721,125 research outputs found
Response to comment on “Antibiotic treatment and appendectomy for uncomplicated acute appendicitis in adults and children: A Systematic Review and Meta-analysis” by Minneci PC et al
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Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Sweet cherry (Prunus avium L.) 'Giorgia', adventitious regeneration from leaves of microplants
No full textWith the aim of exploiting the regenerative capability
of sweet cherry (Prunus avium L.) ‘Giorgia’, experiments
were carried out using suitable plant tissue cultures
established in vitro. Relatively high percentages
of adventitious shoot regeneration were consistently
obtained from in vitro leaves, wounded by three cuts
transversely to the midrib, excised from 3-week-old
proliferating shoots. The regeneration capacity was influenced
by the mineral salts and the plant growth regulator
(PGR) composition of the regeneration medium:
Woody Plant Medium (WPM) gave the best results
and 22.7 μM of 1-Phenyl-3-(1,2,3-thiazol-5-yl)urea
(thidiazuron, TDZ) induced most adventitious regeneration.
The pre-culture of the donor shoots on MS
medium with phloroglucinol (PG)-added improved
the regeneration rate. Histological studies demonstrated
the origin of the adventitious shoots from callus
formed by epidermal and sub-epidermal cells as
well as by the inner cells of the vascular bundles
First insight into the immunological defence system of the sea urchin Spherechinus granularis (Echinoidea, Echinodermata).
No full textImprovement of the P/E window in nanocrystal memories by the use of high-k materials in the control dielectric
No full textIn this paper nanocrystals memories program curves are shown and their saturation points (steady state condition) can be observed. We present a model that relates the voltage shift at the steady state (ΔVTss) to the gate program voltage (VG). Starting from a good agreement between experimental data and simulations for nanocrystals memory cells with a conventional dielectric structure (SiO2), we present the estimated values of the ΔVTss vs VG for different control stacks. Our investigation shows an improvement if a material with a high dielectric constant and a small conduction band-offset with respect to the SiO2, is placed between two SiO2 layers when the first of them is very thin. © 2004 Elsevier Ltd. All rights reserved
Effects of nitridation by N2O or NO on the electrical properties of thin gate or tunnel oxides
No full textWe have studied the effects of nitridation on the leakage current of thin (7-8 nm) gate or tunnel oxides. A polarity dependence of the tunneling current has been found this behavior is related to the presence of a thin silicon oxynitride layer at the SiO2/Si-substrate interface. The oxynitride layer lowers the tunneling current when electrons are injected from the interface where the oxynitride is located (substrate injection). The current flowing across the oxide when electrons are injected from the opposite interface (gate injection) is not influenced by the oxynitride. The increase of nitrogen concentration leads to a decrease of the tunneling current for substrate electron injection
Comparison between textured SnO_2:F and Mo contacts with the p-type layer in p–i–n hydrogenate amorphous silicon solar cells by forward bias impedance analysis
Full text linkIn this paper we compare the performance of the textured SnO_2:F and Mo contacts with the p-type layer in p–i–n hydrogenate amorphous silicon (a-Si:H) solar cells. We use standard current–voltage (I–V) electrical characterization methods coupled with forward bias small signal impedance analysis. We show the efficacy of this technique to determine the effective carrier lifetime in photovoltaic cells. We
show that such effective lifetimes are indeed directly connected to the respective dark diode saturation currents. We also find that the effective lifetime is constant with the temperature in the 0–70 °C range and it is significantly better for the solar cell with Mo diode contact. This also explains well the higher open circuit voltage Voc found under illumination in the Mo/p–i–n cell compared to the SnO_2:F/p–i–n one
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