Ultrastructural data on the life cycle of the parasite, Perkinsus atlanticus (Apicomplexa), on the clam, Ruditapes phillipinarum, in the Mediterranean

An Apicomplexan Perkinsus species has been found parasitizing the clam Ruditapes philippinarum (= Tapes semidecussatus) collected on the Mediterranean coast in the region of the Ebro Delta (Tarragona, Spain). Light and transmission electron microscopy were used to study different stages of this parasite during zoosporulation induced by incubation in thioglycollate medium and seawater. During incubation the trophozoites began zoosporulation, which originated prezoosporangia and zoosporangia at different developmental stages. Successive cytokinesis and nucleokinesis gave rise to prezoospores, which became elongate and differentiated in biflagellated zoospores. The latter presented large mitochondria and an apical complex formed by a conoid, polar ring, micronemes, rhophtries and subpellicular microtubules. The zoosporangium wall showed some typical lamosomes and a discharge tube developed in early phases of incubation. Ultrastructural data were compared with the only four species of the genus Perkinsus previously described. The morphological data, the host and the geographic proximity suggest that the species located on the Mediterranean coast was Perkinsus atlanticus.

Metal-Nitride-oxide-semiconductor light-emitting devices for general lighting.

The potential for application of silicon nitride-based light sources to general lighting is reported. The mechanism of current injection and transport in silicon nitride layers and silicon oxide tunnel layers is determined by electro-optical characterization of both bi- and tri-layers. It is shown that red luminescence is due to bipolar injection by direct tunneling, whereas Poole-Frenkel ionization is responsible for blue-green emission. The emission appears warm white to the eye, and the technology has potential for large-area lighting devices. A photometric study, including color rendering, color quality and luminous efficacy of radiation, measured under various AC excitation conditions, is given for a spectrum deemed promising for lighting. A correlated color temperature of 4800K was obtained using a 35% duty cycle of the AC excitation signal. Under these conditions, values for general color rendering index of 93 and luminous efficacy of radiation of 112 lm/W are demonstrated. This proof of concept demonstrates that mature silicon technology, which is extendable to lowcost, large-area lamps, can be used for general lighting purposes. Once the external quantum efficiency is improved to exceed 10%, this technique could be competitive with other energy-efficient solid-state lighting options. ©2011 Optical Society of America OCIS codes: (230.2090) Electro-optical devices; (150.2950) Illumination.

The cave (La caverna -1952-1969) by Josep Palau i Fabre: theatre versus philosophical allegory in order both to perform and stop the tragic and dark end of the bright art of thinking

What is the use of representing in performance the image of the cave from book VII of Plato’s Republic? Josep Palau i Fabre considers that in Plato’s dialogues the speakers are mere instruments at the service of his dialectical purpose. The aim of this article is to show how, by turning the myth into a tragedy and relying on Heraclitus’s conflict or war of opposites, the playwright succeeds in favouring a sort of thought which is not one-sided or univocal. On the contrary, in Palau i Fabre’s La Caverna, the tragic hero, the released prisoner transformed by the light of Reality and finally killed by his “cavemates” –after having been imprisoned again and having tried to rescue them from their ignorance or shadows– still leaves them his powerful experience of the agonistikós thought, which might bear fruit in their life to come.

Mourning Becomes Electra by Eugene O’Neill: Aeschylus and Plato’s Cave to Create a Dark Drama

The fundamental debt of E. O’Neill’s Mourning Becomes Electra to Aeschylus, and to a lesser degree to Sophocles and Euripides, has been always recognised but, according to the author’s hypothesis, O’Neill might have taken advantage of the Platonic image of the cave in order to magnify his both Greek and American drama. It is certainly a risky hypothesis that stricto sensu cannot be proved, but it is also reader’s right to evaluate the plausibility and the possible dramatic benefit derived from such a reading. Besides indicating to what degree some of the essential themes of Platonic philosophy concerning darkness, light or the flight from the prison of the material world are not extraneous to O’Neill’s work, the author proves he was aware of the Platonic image of the cave thanks to its capital importance in the work of some of his intellectual mentors such as F. Nietzsche or Oscar Wilde. Nevertheless, the most significant aim of the author’s article is to emphasize both the dramatic benefits and the logical reflections derived, as said before, from reading little by little O’Neill’s drama bearing in mind the above mentioned Platonic parameter.

Effects of neurotrophins on synaptic protein expression in the visual cortex of dark reared rats.

Total lack of visual experience [dark rearing (DR)] is known to prolong the critical period and delay development of sensory functions in mammalian visual cortex. Recent results show that neurotrophins (NTs) counteract the effects of DR on functional properties of visual cortical cells and exert a strong control on critical period duration. NTs are known to modulate the development and synaptic efficacy of neurotransmitter systems that are affected by DR. However, it is still unknown whether the actions of NTs in dark-reared animals involve interaction with neurotransmitter systems. We have studied the effects of DR on the expression of key molecules in the glutamatergic and GABAergic systems in control and NT-treated animals. We have found that DR reduced the expression of the NMDA receptor 2A subunit and its associated protein PSD-95 (postsynaptic density-95), of GRIP (AMPA glutamate receptor interacting protein), and of the biosynthetic enzyme GAD (glutamic acid decarboxylase). Returning dark-reared animals to light for 2 hr restored normal expression of the above-mentioned proteins almost completely. NT treatment specifically counteracts DR effects; NGF acts primarily on the NMDA system, whereas BDNF acts primarily on the GABAergic system. Finally, the action of NT4 seems to involve both excitatory and inhibitory systems. These data demonstrate that different NTs counteract DR effects by modulating the expression of key molecules of the excitatory and inhibitory neurotransmitter systems