LC-Circuit Calorimetry

We present a new type of calorimeter in which we couple an unknown heat capacity with the aid of Peltier elements to an electrical circuit. The use of an electrical inductance and an amplifier in the circuit allows us to achieve autonomous oscillations, and the measurement of the corresponding resonance frequency makes it possible to accurately measure the heat capacity with an intrinsic statistical error that decreases as ~t^{-3/2} with measuring time t, as opposed to a corresponding error ~t^{-1/2} in the conventional alternating current (a.c.) method to measure heat capacities. We have built a demonstration experiment to show the feasibility of the new technique, and we have tested it on a gadolinium sample at its transition to the ferromagnetic state.Comment: 6 pages, 5 figure

Wild birds of the Italian Middle Ages: diet, environment and society

Wild birds are intrinsically associated with our perception of the Middle Ages. They often feature in heraldic designs, paintings, and books of hours; few human activities typify the medieval period better than falconry. Prominent in medieval iconography, wild birds feature less frequently in written sources (as they were rarely the subject of trade transactions or legal documents) but they can be abundant in archaeological sites. In this paper we highlight the nature of wild bird exploitation in Italian medieval societies, ranging from their role as food items to their status and symbolic importance. A survey of 13 Italian medieval sites corresponding to 19 ‘period sites’, dated from the fifth to the fifteenth centuries, reveals the occurrence of more than 100 species (certainly an under-estimate of the actual number). Anseriformes and Columbiformes played a prominent role in the mid- and late medieval Italian diet, though Passeriformes and wild Galliformes were also important. In the late Middle Ages, there is an increase in species diversity and in the role of hunting as an important marker of social status

Evidence for a second class of S-adenosylmethionine riboswitches and other regulatory RNA motifs in alpha-proteobacteria

BACKGROUND: Riboswitches are RNA elements in the 5' untranslated leaders of bacterial mRNAs that directly sense the levels of specific metabolites with a structurally conserved aptamer domain to regulate expression of downstream genes. Riboswitches are most common in the genomes of low GC Gram-positive bacteria (for example, Bacillus subtilis contains examples of all known riboswitches), and some riboswitch classes seem to be restricted to this group. RESULTS: We used comparative sequence analysis and structural probing to identify five RNA elements (serC, speF, suhB, ybhL, and metA) that reside in the intergenic regions of Agrobacterium tumefaciens and many other α-proteobacteria. One of these, the metA motif, is found upstream of methionine biosynthesis genes and binds S-adenosylmethionine (SAM). This natural aptamer most likely functions as a SAM riboswitch (SAM-II) with a consensus sequence and structure that is distinct from the class of SAM riboswitches (SAM-I) predominantly found in Gram-positive bacteria. The minimal functional SAM-II aptamer consists of fewer than 70 nucleotides, which form a single stem and a pseudoknot. Despite its simple architecture and lower affinity for SAM, the SAM-II aptamer strongly discriminates against related compounds. CONCLUSION: SAM-II is the only metabolite-binding riboswitch class identified so far that is not found in Gram-positive bacteria, and its existence demonstrates that biological systems can use multiple RNA structures to sense a single chemical compound. The two SAM riboswitches might be 'RNA World' relics that were selectively retained in certain bacterial lineages or new motifs that have emerged since the divergence of the major bacterial groups

Nanofibras de celulosa a partir de batata INTA (Ipomoea batatas) y caña tacuara argentina (Guadua angustifolia)

Las Nanofibras de Celulosa (CNF) tienen la capacidad de servir de refuerzo y formar materiales compuestos con sistemas dinámicos que están mostrando un enorme potencial para mejorar significativamente las tecnologías actuales, y encontrar nuevas y sorprendentes aplicaciones.El objetivo de este trabajo es aislar y caracterizar nanofibras de celulosa de batata (Ipomoea Batatas) y caña tacuara (Guada Angustafolia)EEA San PedroFil: García, Nancy Lis. Universidad Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: D´Accorso, Norma. Universidad Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Química Orgánica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Hidratos de Carbono; ArgentinaFil: Dufresne, Alain. Université Grenoble Alpes. Centre National de la Recherche Scientifique Alpes; FranciaFil: Corbino, Graciela Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Rol, Fleur. Université Grenoble Alpes. Centre National de la Recherche Scientifique Alpes; FranciaFil: Rodríguez Ramírez, Carlos A. Universidad Buenos Aires; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones en Hidratos de Carbono; Argentin

Seminario - taller sobre usos y multiplicación de plantas aromáticas

En el marco del proyecto específico "Desarrollo de tecnologías innovativas para la diversificación, intensificación y diferenciación de la producción de aromáticas para la región pampeana" y en cumplimiento de uno de sus objetivos referente a la transferencia de la información disponible y/o generada por el prouyecto, se plantea la realización de este seminación taller para contribuir al mejor conocimiento del uso de las plantas aromáticas, su multiplicación y manejo sanitario general. Incluye bibliografía de referencia para profundizar sobre la temática.EEA San PedroFil: Paunero, Ignacio Eugenio. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Corbino, Graciela Beatriz. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Segade, Gonzalo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria San Pedro; ArgentinaFil: Madia, Mónica Silvia. Instituto Nacional de Tecnología Agropecuaria (INTA). ProHuerta; ArgentinaFil: Gaetán, Silvia A. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Madia, Marta Susana. Universidad de Buenos Aires. Facultad de Agronomía; Argentin

Sulla variazione della costante dielettrica per la trazione del coibente

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