The cosmic evolution of radio-AGN feedback to z=1

This paper presents the first measurement of the radio luminosity function of 'jet-mode' (radiatively-inefficient) radio-AGN out to z=1, in order to investigate the cosmic evolution of radio-AGN feedback. Eight radio source samples are combined to produce a catalogue of 211 radio-loud AGN with 0.5<z<1.0, which are spectroscopically classified into jet-mode and radiative-mode (radiatively-efficient) AGN classes. Comparing with large samples of local radio-AGN from the Sloan Digital Sky Survey, the cosmic evolution of the radio luminosity function of each radio-AGN class is independently derived. Radiative-mode radio-AGN show an order of magnitude increase in space density out to z~1 at all luminosities, consistent with these AGN being fuelled by cold gas. In contrast, the space density of jet-mode radio-AGN decreases with increasing redshift at low radio luminosities (L_1.4 < 1e24 W/Hz) but increases at higher radio luminosities. Simple models are developed to explain the observed evolution. In the best-fitting models, the characteristic space density of jet-mode AGN declines with redshift in accordance with the declining space density of massive quiescent galaxies, which fuel them via cooling of gas in their hot haloes. A time delay of 1.5-2 Gyr may be present between the quenching of star formation and the onset of jet-mode radio-AGN activity. The behaviour at higher radio luminosities can be explained either by an increasing characteristic luminosity of jet-mode radio-AGN activity with redshift (roughly as (1+z) cubed) or if the jet-mode radio-AGN population also includes some contribution of cold-gas-fuelled sources seen at a time when their accretion rate was low. Higher redshifts measurements would distinguish between these possibilities.Comment: Accepted for publication in MNRA

Mineralogy of some soils from the Amazonia Sedimentary Basin.

ABSTRACT: The Amazonia Forest is an important biome that possesses great diversity of fauna and flora, which can play a significant role in several science areas, specially, the gene reserve for the future of humankind. Nevertheless, it is a very poorly understood environment, particularly the basis of this ecosystem, its soils. This study was conducted to gain insight in the mineralogy of important soils classes of the Amazonia sedimentary basin. The soils in the upland position in the landscape are developed from tertiary sediments belonging to the Alter do Chão series and those in the floodplain position are derived from quaternary, more specifically, Holocene´s sediments. Sand, silt and clay fractions were separated and X-ray diffraction analysis was conducted. Very simple mineralogy composed basically of quartz in the coarser fractions and kaolinite, goethite and anatase for the finer fraction was found for the Oxisol, the Ultisol and the Entisol from an upland toposequence but differences in kaolinite crystallography could be noticed among them. Gibbsite was virtually absent, in spite of the advanced degree of development of most of these soils. More distinctive mineralogy was revealed for the soils developed in the more recent sediments with quartz and feldspars in the sand and silt fractions and a suite of 2:1 minerals also appearing in their clay fraction, besides kaolinite and goethite. In one upland soil petroplinthite is the main feature and its mineralogy reflected its environment of formation which is usually associated with level to gently sloping areas with fluctuating water table

Geotechnical characterization of Vertisols from Bahia State, Brazil.

Despite the existence of vertic soils with predominance of kaolinite is reported around the world, there are few studies shown the influence of this clay mineral in their geotechnical characteristics. The work aimed to perform a geotechnical characterization of Vertisols from Bahia, Brazil, besides understanding the influence of physical, chemical and mineralogical properties on the geotechnical behavior. Three Vertisols were collected in Juazeiro city, in a semi-arid region, one kaolinitic Vertisol and two smectite Vertisols. Other three Vertsols were collected in Recôncavo region, all presented clay mineralogy with codominance of smectite and kaolinite (Sm-K). A geotechnical characterization was carried out in their diagnostic horizons, determining properties such as granulometric curve, clay activity, linear expansion coefficient, compaction capacity, cohesion (c?), and internal friction angle (&#981;) of saturated soils. We observed that the clay content was the attribute that most influenced the geotechnical characteristics. All soils showed expansion potential above 0.01, considered as very high. The kaolinitic Vertisol showed the lowest clay activity. However, the clay content of 68% contributed to this soil to present an expansion potential similar to the smectite Vertisol with clay content of 35%. The major values of soil compaction were observed for the kaolinitic Vertisol, which presented greater reduction of void ratio and higher density as a function of moisture increase. For this soil, the optimal moisture content (OMC) and maximum dry density (MDD) were 22% and 1.65 g cm-3, respectively. The other soils presented OMC between 18-41% and MDD between 1.75-1.24 g cm-3. These smectite-soils, MDD decreased with increasing of OMC. All soils had low c? values, which is expected for high clay content soils. The c? values increased with increasing of kaolinite and decreased with increasing of clay content. The kaolinite Vertisol showed c? of 0.19 kgf cm-2. The c? values to Sm-K Vertisols ranged between 0.05-0.11 kgf cm-2. As for smectite-soil, c? values ranged between 0.02-0.03 kgf cm-2. Low &#981; values were observed for all soils, which indicates low shear resistance. In its turn, &#981; was more influenced by granulometry, in which higher levels of sand and gravel provided higher &#981;, independently of the type of clay. Vertisols with different mineralogy present different geotechnical characteristics. Keywords: Smectite; kaolinite; expansive soil

Elastin is Localised to the Interfascicular Matrix of Energy Storing Tendons and Becomes Increasingly Disorganised With Ageing

Tendon is composed of fascicles bound together by the interfascicular matrix (IFM). Energy storing tendons are more elastic and extensible than positional tendons; behaviour provided by specialisation of the IFM to enable repeated interfascicular sliding and recoil. With ageing, the IFM becomes stiffer and less fatigue resistant, potentially explaining why older tendons become more injury-prone. Recent data indicates enrichment of elastin within the IFM, but this has yet to be quantified. We hypothesised that elastin is more prevalent in energy storing than positional tendons, and is mainly localised to the IFM. Further, we hypothesised that elastin becomes disorganised and fragmented, and decreases in amount with ageing, especially in energy storing tendons. Biochemical analyses and immunohistochemical techniques were used to determine elastin content and organisation, in young and old equine energy storing and positional tendons. Supporting the hypothesis, elastin localises to the IFM of energy storing tendons, reducing in quantity and becoming more disorganised with ageing. These changes may contribute to the increased injury risk in aged energy storing tendons. Full understanding of the processes leading to loss of elastin and its disorganisation with ageing may aid in the development of treatments to prevent age related tendinopathy

Atributos micromorfológicos de solos do Projeto Jaíba, Norte de Minas Gerais.

Avaliaram-se micromorfologicamente amostras indeformadas de horizontes B de Cambissolo Ta (CTa), Latossolos Vermelho-Escuros (LE), Podzólico Vermelho-Escuro, solos desenvolvidos de calcário do Grupo Bambuí em áreas de influência do Projeto Jaíba, Norte de Minas Gerais, em condições naturais e sob uso agrícola, irrigado ou não (LE)

Caracterização de concreções ferro manganosas em solos do Projeto Jaíba, Norte de Minas Gerais.

A ocorrência de concreções ferro-manganosas variáveis quanto ao diâmetro e formato são comuns em solos do Projeto Jaíba. Normalmente, tendem aumentar de tamanho com a profundidade nos Cambissolos e Vertissolos e a permanecer pequenas nos Latossolos, onde são mais lisas (menos corroídas) e mais arredondadas (chumbinho de caça). Com o objetivo de caracterizar estas concreções, foram formados 4 grupos de acordo com o diâmetro, as quais após trituradas foram caracterizadas química (fluorescência de raios-X - análise química total) mineralógica (difração de raios-X) e micromorfologicamente