Erasing the glassy state in magnetic fine particles

BaFe10.4Co0.8Ti0.8O19 magnetic fine particles exhibit most of the features attributed to glassy behavior, e.g., irreversibility in the hysteresis loops and in the zero-field-cooling and field-cooling curves extends up to very high fields, and aging and magnetic training phenomena occur. However, the multivalley energy structure of the glassy state can be strongly modified by a field-cooling process at a moderate field. Slow relaxation experiments demonstrate that the intrinsic energy barriers of the individual particles dominate the behavior of the system at high cooling fields, while the energy states corresponding to collective glassy behavior play the dominant role at low cooling fields.

Reply to "Comment on 'Erasing glassy state in magnetic fine particles'"

The Comment affirms that no phase transition occurs in spin-glass systems with an applied magnetic field. However, only according to the droplet model is this result expected. Other models do not predict this result and, consequently, it is under current discussion. In addition, we show how the experimental results obtained in our system correspond to a cluster glass rather than to a true spin glass.

Fine structure of the vaccinia virus gene encoding the precursor of the major core protein 4 a.

A 6008 base pair fragment of the vaccinia virus DNA containing the gene for the precursor of the major core protein 4 a, which has been designated P4 a, was sequenced. A long open reading frame (ORF) encoding a protein of molecular weight 102,157 started close to the position where the P4 a mRNA had been mapped. Analysis of the mRNA by S1 nuclease mapping and primer extension indicated that the 5' end defined by the former method is not the true 5' end. This suggests that the P4 a coding region is preceded by leader sequences that are not derived from the immediate vicinity of the gene, similar to what has been reported for another late vaccinia virus mRNA. The sequenced DNA contained several further ORFs on the same, or opposite DNA strand, providing further evidence for the close spacing of protein-coding sequences in the viral genome.

Fine-Tuning Translation Kinetics Selection as the Driving Force of Codon Usage Bias in the Hepatitis A Virus Capsid

Hepatitis A virus (HAV), the prototype of genus Hepatovirus, has several unique biological characteristics that distinguish it from other members of the Picornaviridae family. Among these, the need for an intact eIF4G factor for the initiation of translation results in an inability to shut down host protein synthesis by a mechanism similar to that of other picornaviruses. Consequently, HAV must inefficiently compete for the cellular translational machinery and this may explain its poor growth in cell culture. In this context of virus/cell competition, HAV has strategically adopted a naturally highly deoptimized codon usage with respect to that of its cellular host. With the aim to optimize its codon usage the virus was adapted to propagate in cells with impaired protein synthesis, in order to make tRNA pools more available for the virus. A significant loss of fitness was the immediate response to the adaptation process that was, however, later on recovered and more associated to a re-deoptimization rather than to an optimization of the codon usage specifically in the capsid coding region. These results exclude translation selection and instead suggest fine-tuning translation kinetics selection as the underlying mechanism of the codon usage bias in this specific genome region. Additionally, the results provide clear evidence of the Red Queen dynamics of evolution since the virus has very much evolved to re-adapt its codon usage to the environmental cellular changing conditions in order to recover the original fitness.

L'experiència pilot desenvolupada a partir del projecte d'innovació "La gestió integrada de la qualitat, el medi ambient i la seguretat en la docència experimental dels estudis de grau de les Facultats de Belles Arts"

Es presenta un projecte d'innovació docent, la recerca desevolupada del qual va incorporar aspectes relacionats amb la seguretat i la sostenibilitat dels procediments realitzats als tallers i laboratoris de les Facultats de Belles Arts, aplicant criteris de gestió de qualitat. Els resultats d'aquestes investigacions tenen una extensió social en l'àmbit de les Belles Arts en general. El projecte d'innovació docent va aplicar criteris de gestió de qualitat. La recerca desenvolupada va incorporar aspectes relacionats amb la seguretat i la sostenibilitat dels procediments als tallers i laboratoris de les Facultats de Belles Arts. Els resultats d¿aquestes investigacions tenen una extensió social en l'àmbit de les Belles Arts en general. Amb aquest projecte es va redissenyar un model de procediment normalitzat de treball (PNT) que 11 tallers diferents de les Facultats de BBAA de Barcelona, Conca i València van utilitzar per a elaborar 14 PNT i 3 vídeos de suport. Aquests es van aplicar durant una experiència pilot (curs 2009-2010). El nombre de participants en l¿experiència va ser de 211 alumnes, 15 professors, 10 tècnics de taller, majoritàriament de BBAA de la Universitat de Barcelona. L'experiència pilot va demostrar satisfactòriament la viabilitat de l'aplicació del model de PNT adoptat i els beneficis, de la seva aplicació, orientats a la millora continuada de la qualitat docent i de la investigació. Per concloure el projecte es va elaborar el procediment general (PG) que determina les pautes per a redactar un PNT. Aquest PG va ser aprovat recentment per la CSSMA del Centre2 i es podrà aplicar en el futur en la Facultat de BBAA de Barcelona. Sobre l'experiència s'han realitzat les publicacions pertinents (un llibre i un DVD) i s'ha participat també en dos congressos.