The locomotion pattern of Baurusuchus salgadoensis Carvalho, Nobre & Campos, 2005 and the distribution of Baurusuchidae in Gondwanaland

Baurusuchus salgadoensis Carvalho, Nobre & Campos, 2005 is a ziphodont mesoeucrocodylian closely related to the Sebecosuchia. Cranial features indicate that this species had terrestrial predatory habits. The postcranial skeleton of B. salgadoensis show distinctive characteristics when compared to extant Crocodylomorpha. The dorsal vertebrae are close articulated with short and craniocaudally expanded neural spines, specially the posterior ones. The sacral vertebrae are robust and have the lateral processes highly fused to the ilium. The anterior caudal vertebrae are robust as the sacral ones but their neural spines are more stout, anteriorlly expanded and higher. The close articulation of the dorsal vertebrae may indicate a less flexible dorsal spine, ideal to limb-driven methods of locomotion. The high and expanded neural spines of the posterior dorsal and sacral vertebrae are associated to muscle attachment from the osteoderms and the pelvic musculature, all used in the limb-driven locomotion. The appendicular bones of B. salgadoensis are long and stout. They show a straight aspect of their diaphysis and very well- developed epiphysis. The femur is long when compared to extant crocodilians, showing a straight aspect in lateral view and a slight sigmoid aspect in frontal view. There is a small axial torsion at its proximal end. The fourth trochanter is pronouced and posteriorlly oriented. The proximal end possess a mesial projection that articulates itself to the illium, similar to those of Protosuchia and thecodont archosaurs as the Rauisuchia. The illium of B. salgadoensis present a lateral and posteriorlly expanded postaccetabular crest, similar to those observed in Rauisuchia and Protosuchia, referred as overhanging ilium. This pattern of articulation is observed in the rauisuchian thecodonts and interpreted as a characteristic trait of those able erect-posture and limb-driven predators of Triassic environments. B. salgadoensis exoskeleton has only two dorsal osteoderm rows that run from the neck to the tip of the tail. Most of the osteoderms are wider than longer, with a round lateral portion that does not articulate to any flank osteoderm. The only morphological difference appears at the caudalmost portion of the tail, where the osteoderms are craniocaudally elongated. The medial portion has little variation along the scutes rows and may bear medial lamellar dorsoventral structures of articulation to the adjacent bony plate. The anterior articular facet is discreet and the osteoderms are not as imbricated as occur in other crocodyliforms and even may not be imbricated at all. The pelvic region osteoderms have the tallest keel of the row that runs from the anterior articular facet to posteriosmost portion of the osteoderm. B. salgadoensis has a light exoskeleton and then is less encumbranced by it. Therefore, becaming more agile. The imbrication of dorsal armor assists the limb-driven locomotion of many crocodyliform by reducing the flexibility of the dorsal spine during the high-walk (erect stance). Therefore the long and stout limb bones, overhanging crest of the illium and the light weighted armor, also allowed to B. salgadoensis to have the limb-driven locomotion without this pattern of osteoderms. These anatomical data may indicate how the Baurusuchidae had a wide distribution in Gondwanaland as they were able to move across large distances

Occurrence of Gastroliths in _Baurusuchus_ (Baurusuchidae, Mesoeucrocodylia) from Adamantina Formation, Bauru Basin

The fossil record of Baurusuchidae Mesoeucrocodylia in the General Salgado county and its surroundings is one of the best regarding preservation, completeness and articulation of skull and skeleton remains, including specimens that shown even the most delicate bone structures and cartilaginous tissues. 

One of them, UFRJ DG 288-R, has preserved its skull and about 80% of its skeleton. During the removal of the rock matrix, on what should be the specimen’s abdominal region, together with fragments of gastralia were observed some small well-polished weathered angulous to subrounded clasts, presumed to be gastroliths. 

These xenoliths occur in a restrict cluster, where at least four peeble-sized stones are visible in the surface of the specimen. The texture and fabrics of these rock fragments differs from the surrounding matrix, presenting darker purplish tones. In thin section, one of the fragments revealed isotropic texture, with opaque minerals in abundance, of euhedric to subhedric habits. The mineralogical composition presents mainly clay minerals as weathering products; biotite and chlorite are common, being the last the result of hidratation of the first. Although highly altered, the low quartz content, small-sized and well-formed crystals suggests maphic composition in volcanic context, possibly representing a basalt fragment. 

In extant Crocodyliformes, the occurrence of gastroliths is commonly associated with food processing in the stomach, diving ballast, hunger stress and/or supplementary mineral ingestion. 

As baurusuchids are characterized as medium to large size fully terrestrial predator/scavengers, based on skeletal data, the ballast function of gasthroliths is excluded in this case. As mentioned above, extant crocodyliforms such as _Caiman_ and _Crocodylus_ ingest stones when under stressful conditions of lack of food, water or when in high population density. Osteoderms are one of the primary sources for calcium and a reservoir for the homeostasis. The hunger stress can be observed in the osteoderms histological cuts as an abnormal concentration of osteoclasts at its inner region overwhelming the presence of osteoblasts and consuming the osteocytes. The preservation of osteoderms associated with gasthroliths may reveal if the stone ingestion in baurusuchids is a normal or driven by hunger behavior. 

The paleoenvironmental conditions dominating the Adamantina Formation during the Late Cretaceous are considered mainly arid, marked with strong seasonality, alternating long droughts and short rainy periods, associated with flashflood events. The stressful condition created during the dry season would cause famine and mass mortality, thus forcing animals to endure or escape. The baurusuchids underwent the dry seasons through behavorial responses of self burial and probably stone ingestion, although natural bahavior cannot be eliminated as a cause. 

Financial support provided by Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq, grant no 305780/2006–9), Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) and Instituto Virtual de Paleontologia/ Fundação Carlos Chagas Filho de Amparo à Pesquisa do Estado do Rio de Janeiro (IVP/FAPERJ, grant no E–26/152.541/2006).
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Standardized MET value underestimates the energy cost of treadmill running in men

AbstractThe main purpose of the present study was to compare the reference metabolic equivalent (MET) value and observed resting oxygen uptake (VO2) for defining cardiorespiratory fitness (VO2max) and characterizing the energy cost of treadmill running. A heterogeneous cohort of 114 healthy men volunteered to participate. In Part 1 of the study, 114 men [mean±SD, age: 24±5 years; height: 177.1±7.9 cm; body mass: 75.0±10.0 kg] visited the laboratory twice for assessment of resting and maximal VO2 values to compare the reference MET value vs. observed resting VO2 and to investigate the association between resting VO2 and VO2max. In Part 2, 14 of the 114 men visited the laboratory once more to perform a 30-min bout of running at 8.0 km∙h−1/8.3 METs. The mean observed resting VO2 of 3.26 mL·kg−1·min−1 was lower than the reference MET value of 3.5 mL·kg−1·min−1 (P&lt;0.001). Resting and maximal VO2 values relative to total body mass and fat-free mass were positively correlated (R=0.71 and 0.60, respectively; P&lt;0.001). The maximal MET and energy cost of treadmill running were consequently underestimated when calculated using the reference MET value only for those with low VO2max (P=0.005 to P&lt;0.001). In conclusion, the reference MET value considerably overestimated observed resting VO2 in men with low VO2max, resulting in underestimations of the maximal MET, exercise intensity prescription, and the energy cost of running.</jats:p

Controle Linear aplicado a uma nanorrede de corrente contínua que opera em modo ilhado utilizando modelo médio de pequenos sinais/ Linear Control applied to a direct current nano-network that operates in island mode using small signals medium model

As nanorredes de corrente contínua (CC) surgiram, nos últimos anos, como alternativa à crescente demanda energética das unidades consumidoras. Para nanorredes de corrente contínua, bem como todos os sistemas que operam em modo ilhado, o balanço instantâneo de potência é de grande importância para manter a tensão do barramento dentro dos limites de projeto. Para tal, nesse trabalho é feita a linearização do sistema (intrinsecamente não-linear), assim possibilitando a aplicação de técni-cas clássicas de controle. Portanto, faz-se a modelagem através de técnicas conhecidas do modelo mé-dio de pequenos sinais para obter as funções de transferência necessárias ao controle da tensão CC do barramento da nanorrede. Adicionalmente, projeta-se um sistema de controle e são obtidas as faixas de operação onde a estabilidade do sistema é garantida. A nanorrede é então testada através de simula-ções para validar o sistema de controle proposto bem como a análise da estabilidade

The complete genome sequence of Chromobacterium violaceum reveals remarkable and exploitable bacterial adaptability

Chromobacterium violaceum is one of millions of species of free-living microorganisms that populate the soil and water in the extant areas of tropical biodiversity around the world. Its complete genome sequence reveals (i) extensive alternative pathways for energy generation, (ii) ≈500 ORFs for transport-related proteins, (iii) complex and extensive systems for stress adaptation and motility, and (iv) wide-spread utilization of quorum sensing for control of inducible systems, all of which underpin the versatility and adaptability of the organism. The genome also contains extensive but incomplete arrays of ORFs coding for proteins associated with mammalian pathogenicity, possibly involved in the occasional but often fatal cases of human C. violaceum infection. There is, in addition, a series of previously unknown but important enzymes and secondary metabolites including paraquat-inducible proteins, drug and heavy-metal-resistance proteins, multiple chitinases, and proteins for the detoxification of xenobiotics that may have biotechnological applications