Ruminal Proteolysis in Forages with Distinct Endopeptidases Activities

Improving livestock efficiency in utilisation of nitrogen resources continues to be a major environmental and economic objective. Zhu et al. (1999) have shown that plant endopeptidases are activated as a response to cutting stress. Previous work in our laboratory explored over 300 entries of forage genotypes and found a broad diversity in enzymatic activity by means of hydrolysis in gelatine and direct autolysis assays in forage tissues. The objective of this work was to assess if the species previously identified as having high or low endopeptidase activity, would behave consistently when exposed to ruminal microbial proteolysis

Solubility of nickel in slags equilibrated with Ni-S melt

To provide thermodynamic data for converting the nickel matte to liquid nickel, an experimental study was conducted in the phase equilibrium between the Ni-S melt and FeOX-SiO2, FeOX-CaO or CaO-Al2O3 based slag melted in a magnesia crucible at 1773 and 1873 K. pSO2 was controlled at 10.1 kPa while pO2 and pS2 ranged between those where NiO precipitated and Ni3S2 formed, respectively. The nickel content in the slag and the sulfur content in the metal at given pO2 and pS2 were smallest for the CaO-Al2O3 based slag. Both decreased with increasing temperature. At 1873 K, the content of nickel in the CaO-Al2O3 based slag at pO2 of 10 Pa (near the precipitation of NiO) was 4%, while the content of sulfur in alloy is 0.4 mass %. Thus, the CaO-Al2O3 base slag at 1873 K would be suitable for direct converting of Ni3S2 to metallic nickel. The distribution behavior of nickel between the slag and the Ni-S melt was discussed based on the concept of oxidic and sulfidic dissolution

Un yacimiento de cazadores-recolectores marinos en la terraza litoral de Bajo Patache, sur de Iquique

El presente artículo presenta los nuevos e importantes descubrimientos en la terraza litoral al pie del oasis de niebla, a partir de Noviembre de 2003, que junto a estudios anteriores conforman un cuadro general bastante completo de los patrones de asentamiento, modus vivendi, costumbres y actividades económicas de los antiguos pobladores costeros del norte de Chile, que reafirman la enorme importancia que adquirió el ecosistema de oasis de niebla costero en el género de vida, tipos de asentamiento y desplazamientos de los cazadores-recolectores marinos del litoral norte.Cet article présente les nouvelles et importantes découvertes dans la terrasse littorale se trouvant au pied de l’oasis de brume, à partir de Novembre 2003, lesquelles, associées à des études antérieures, conforment un cadre général très complet de patrons d’établissement, modus vivendi, d’habitudes et d’activités économiques des anciens habitants de la côte dans le nord du Chili, ce qui renforce l’importance de l’écosystème de l’oasis de brume côtier quant à la connaissance du mode de vie, de types d’établissement et de déplacements des chasseurs-cueilleurs marins du littoral du nord.This paper presents important new findings on the terrace at the foot of coastal mist oases, from November 2003, which together with previous studies form a fairly complete picture of settlement patterns, modus vivendi, customs and economic activities of the ancient inhabitants of northern coastal Chile, to reaffirm the great importance that acquired the ecosystem of coastal mist oases in the way of life, types of settlement and displacement of hunter-gatherers of the north coast marine

Un yacimiento de cazadores-recolectores marinos en la terraza litoral de Bajo Patache, sur de Iquique

El presente artículo presenta los nuevos e importantes descubrimientos en la terraza litoral al pie del oasis de niebla, a partir de Noviembre de 2003, que junto a estudios anteriores conforman un cuadro general bastante completo de los patrones de asentamiento, modus vivendi, costumbres y actividades económicas de los antiguos pobladores costeros del norte de Chile, que reafirman la enorme importancia que adquirió el ecosistema de oasis de niebla costero en el género de vida, tipos de asentamiento y desplazamientos de los cazadores-recolectores marinos del litoral norte.Cet article présente les nouvelles et importantes découvertes dans la terrasse littorale se trouvant au pied de l’oasis de brume, à partir de Novembre 2003, lesquelles, associées à des études antérieures, conforment un cadre général très complet de patrons d’établissement, modus vivendi, d’habitudes et d’activités économiques des anciens habitants de la côte dans le nord du Chili, ce qui renforce l’importance de l’écosystème de l’oasis de brume côtier quant à la connaissance du mode de vie, de types d’établissement et de déplacements des chasseurs-cueilleurs marins du littoral du nord.This paper presents important new findings on the terrace at the foot of coastal mist oases, from November 2003, which together with previous studies form a fairly complete picture of settlement patterns, modus vivendi, customs and economic activities of the ancient inhabitants of northern coastal Chile, to reaffirm the great importance that acquired the ecosystem of coastal mist oases in the way of life, types of settlement and displacement of hunter-gatherers of the north coast marine

Linking learning with governance in networks and clusters: key issues for analysis and policy

In this paper we analyse the relationship between governance and learning in clusters and networks. In particular, we see these two key elements as interdependent, suggesting that, under particular circumstances, such interdependence may drive clusters and networks towards a dynamic development trajectory. A pure ‘governance perspective’ makes the development of any locality dependent on the system of powers which exists within the locality or across the global value chain. In parallel, a pure ‘competence-based approach’ focuses mainly on the capabilities of actors to learn and undertake activities. In contrast, we open the prospects for an interdependent relation that may change the actual competences of actors as well as the governance settings and dynamics in networks and clusters. When supported by public policies, the learning process may have the potential to modify the governance environment. Simultaneously, the learning process is intrinsically influenced by economic power, which may seriously affect the development prospects of clusters and networks. This is why an intertwined consideration of both aspects is necessary to promote specific approaches to learning and to design appropriate policies. In this paper we offer two preliminary case studies to clarify some of these dynamics: the first taken from the computers cluster in Costa Rica and the second from an Italian bio-pharmaceutical firm and its production network. The first case study refers to the software cluster that was created from scratch in Costa Rica thanks to an enlightened government policy in coordination with new local enterprises and an important foreign direct investor; while the second reflects on the ability of an individual company to create a network of relationships with large transnational companies in order to acquire new competences without falling into a subordinate position with respect to its larger partners

Metástasis cutáneas de cáncer de mama

El objetivo de este estudio es identificar perfiles correspondientes a la metástasis cutánea en el cáncer de mama mediante el análisis de marcadores tumorales tales como MUC1 y antígenos carbohidratos asociados

The Long Life of Birds: The Rat-Pigeon Comparison Revisited

The most studied comparison of aging and maximum lifespan potential (MLSP) among endotherms involves the 7-fold longevity difference between rats (MLSP 5y) and pigeons (MLSP 35y). A widely accepted theory explaining MLSP differences between species is the oxidative stress theory, which purports that reactive oxygen species (ROS) produced during mitochondrial respiration damage bio-molecules and eventually lead to the breakdown of regulatory systems and consequent death. Previous rat-pigeon studies compared only aspects of the oxidative stress theory and most concluded that the lower mitochondrial superoxide production of pigeons compared to rats was responsible for their much greater longevity. This conclusion is based mainly on data from one tissue (the heart) using one mitochondrial substrate (succinate). Studies on heart mitochondria using pyruvate as a mitochondrial substrate gave contradictory results. We believe the conclusion that birds produce less mitochondrial superoxide than mammals is unwarranted