In vivo cranial bone strain and bite force in the agamid lizard Uromastyx geyri

In vivo bone strain data are the most direct evidence of deformation and strain regimes in the vertebrate cranium during feeding and can provide important insights into skull morphology. Strain data have been collected during feeding across a wide range of mammals; in contrast, in vivo cranial bone strain data have been collected from few sauropsid taxa. Here we present bone strain data recorded from the jugal of the herbivorous agamid lizard Uromastyx geyri along with simultaneously recorded bite force. Principal and shear strain magnitudes in Uromastyx geyri were lower than cranial bone strains recorded in Alligator mississippiensis, but higher than those reported from herbivorous mammals. Our results suggest that variations in principal strain orientations in the facial skeleton are largely due to differences in feeding behavior and bite location, whereas food type has little impact on strain orientations. Furthermore, mean principal strain orientations differ between male and female Uromastyx during feeding, potentially because of sexual dimorphism in skull morphology

Scattering Compensation for Deep Brain Microscopy: The Long Road to Get Proper Images

Multiphoton microscopy is the most widespread method for preclinical brain imaging when sub-micrometer resolution is required. Nonetheless, even in the case of optimal experimental conditions, only a few hundred micrometers under the brain surface can be imaged by multiphoton microscopy. The main limitation preventing the acquisition of images from deep brain structures is the random light scattering which, until recently, was considered an unsurmountable obstacle. When in 2007 a breakthrough work by Vellekoop and Mosk [1] proved it is indeed possible to compensate for random scattering by using high resolution phase modulators, the neuro-photonics community started chasing the dream of a multiphoton microscopy capable of reaching arbitrary depths within the brain. Unfortunately, more than 10 years later, despite a massive improvement of technologies for scattering compensation in terms of speed, performances and reliability, clear images from deep layers of biological tissues are still lacking. In this work, we review recent technological and methodological advances in the field of multiphoton microscopy analyzing the big issue of scattering compensation. We will highlight the limits hampering image acquisition, and we will try to analyze the road scientists must tackle to target one of the most challenging issue in the field of biomedical imaging

Anatomy and Cranial Functional Morphology of the Small-Bodied Dinosaur Fruitadens haagarorum from the Upper Jurassic of the USA

Heterodontosaurids are an important but enigmatic and poorly understood early radiation of ornithischian dinosaurs. The late-surviving heterodontosaurid Fruitadens haagarorum from the Late Jurassic (early Tithonian) Morrison Formation of the western USA is represented by remains of several small (<1 metre total body length, <1 kg body mass) individuals that include well-preserved but incomplete cranial and postcranial material. Fruitadens is hypothesized to represent one of the smallest known ornithischian dinosaurs. We describe the cranial and postcranial anatomy of Fruitadens in detail, providing comparisons to all other known heterodontosaurid taxa. High resolution micro-CT data provides new insights into tooth replacement and the internal anatomy of the tooth-bearing bones. Moreover, we provide a preliminary functional analysis of the skull of late-surviving heterodontosaurids, discuss the implications of Fruitadens for current understanding of heterodontosaurid monophyly, and briefly review the evolution and biogeography of heterodontosaurids. The validity of Fruitadens is supported by multiple unique characters of the dentition and hindlimb as well as a distinct character combination. Fruitadens shares highly distinctive appendicular characters with other heterodontosaurids, strengthening monophyly of the clade on the basis of the postcranium. Mandibular morphology and muscle moment arms suggest that the jaws of late-surviving heterodontosaurids, including Fruitadens, were adapted for rapid biting at large gape angles, contrasting with the jaws of the stratigraphically older Heterodontosaurus, which were better suited for strong jaw adduction at small gapes. The lack of wear facets and plesiomorphic dentition suggest that Fruitadens used orthal jaw movements and employed simple puncture-crushing to process food. In combination with its small body size, these results suggest that Fruitadens was an ecological generalist, consuming select plant material and possibly insects or other invertebrates

Bite force and cranial bone strain in four species of lizards

In vivo bone strain data provide direct evidence of strain patterns in the cranium during biting. Compared to mammals, in vivo bone strains in lizard skulls are poorly documented. This paper presents strain data from the skulls of Anolis equestris, Gekko gecko, Iguana iguana and Salvator merianae during transducer biting. Analysis of variance was used to investigate effects of bite force, bite point, diet, cranial morphology and cranial kinesis on strain magnitudes. Within individuals the most consistent determinants of variance in bone strain magnitudes are gage location and bite point, with the importance of bite force varying between individuals. Inter-site variance in strain magnitudes—strain gradient—is present in all individuals, and varies with bite point. Between individuals within species, variance in strain magnitude is driven primarily by variation in bite force, not gage location or bite point, suggesting that inter-individual variation in patterns of strain magnitude is minimal. Between species, variation in strain magnitudes is significantly impacted by bite force and species membership, as well as by interactions between gage location, species, and bite point. Independent of bite force, species differences in cranial strain magnitudes may reflect selection for different cranial morphology in relation to feeding function, but what these performance criteria are is not clear. The relatively low strain magnitudes in Iguana and Uromastyx compared to other lizards may be related to their herbivorous diet. Cranial kinesis and the presence or absence of postorbital and supratemporal bars are not important determinants of inter-specific variation in strain magnitudes

A 'mãe palmeira' ante a privatização de terras sob uso comum: desafios para a conservação do babaçu por quilombolas no vale do Mearim, Brasil.

A relação entre palmeiras e comunidades é fator significativo para a constituição de territórios tradicionais e para a conservação de relevantes ecossistemas. Designada como 'mãe do povo', a palmeira babaçu 'Attalea speciosa (Mart. ex Spreng.)' tem provido historicamente o sustento de quilombos em terras de uso comum, nas áreas de sua ocorrência. Porém, contínuos assédios governamentais e civis de privatização ameaçam tais processos socioeconômicos e ecológicos, sob um mercado de terras desfavorável à tradição quilombola. É analisado o caso do quilombo Monte Alegre-Olho D'Água dos Grilos, no vale do rio Mearim, Maranhão, atualmente sob processo ilegal de privatização de terras coletivas. Quilombolas, em parceria de pesquisa-ação com os autores, realizaram inventário da vegetação arbórea no seu território. Resultados desse inventário e dados da memória oral sobre a vegetação arbórea permitem refletir sobre bases conceituais para a conservação dos babaçuais. Os resultados indicam que a regularização fundiária na modalidade coletiva é necessária, mas não suficiente para evitar a fragmentação da cobertura vegetal prejudicial à conservação florestal. Conclui-se que os direitos territoriais reivindicados, embora garantidos constitucionalmente, só serão concretizados se Estado e sociedade respeitarem a renovação da tradição do uso comum pelos quilombolas, conforme preconizado na revisada 'teoria dos comuns manejados

Acesso à ATER e os principais problemas técnicos enfrentados pela agricultura familiar no Nordeste paraense.

O presente trabalho analisou o acesso à assistência técnica, o órgão que presta o serviço, avaliação desta assistência, e os principais problemas técnico-produtivos enfrentados por produtores quilombolas, assentados e pequenos proprietários no Nordeste Paraense. A pesquisa foi realizada a partir da aplicação de questionários, no inicio de 2015, totalizando 345 entrevistados, de acordo com três categorias fundiárias: assentados, quilombolas, e produtores em pequenas propriedades particulares, e em quatro Regiões de Integração (RI) do Nordeste Paraense: Caetés, Capim, Guamá e Tocantins. Os dados coletados foram inseridos, em plataforma SQL, exportados para planilhas Excel, e analisados no programa estatístico Stata. Identificou-se insuficiente oferta de assistência técnica e extensão rural ao agricultor familiar, pois menos de um terço dos agricultores indicaram ter acesso a estes serviços. Dentre as categorias fundiárias e regiões de integração, proporcionalmente o acesso foi mais frequente entre produtores assentados (41,3%) e na Região Capim (42,5%). Na avaliação da assistência técnica recebida, constatou-se que produtores da categoria assentados e RI Tocantins indicaram maior satisfação. Notou-se que dois terços dos entrevistados enfrentam problemas técnicos, sendo que a frequência relativa é maior entre pequenos proprietários. O principal problema enfrentado é a falta de mecanização, seguido da podridão da raiz de mandioca e baixa fertilidade do solo. Dentre as Regiões de Integração, maior frequência de problemas técnicos ocorreu na RI Guamá. Evidenciou-se a escassez de políticas públicas para a agricultura familiar no Nordeste Paraense, e a demanda por uma assistência técnica eficaz e por maior acesso ao crédito rural. A presença de extensionistas apoiaria decisivamente o produtor a solucionar ao menos parte dos problemas citados pelos agricultoresCOINTER - PDVAgro

Transformações recentes e incertezas para o extrativismo de babaçu no território do médio Mearim, Maranhão.

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Inverse dynamic modelling of jumping in the red-legged running frog, Kassina maculata

Although the red-legged running frog, Kassina maculata, is secondarily a walker/runner, it retains the capacity for multiple locomotor modes, including jumping at a wide range of angles (nearly 70 deg). Using simultaneous hind limb kinematics and single-foot ground reaction forces, we performed inverse dynamics analyses to calculate moment arms and torques about the hind limb joints during jumping at different angles in K. maculata. We show that forward thrust is generated primarily at the hip and ankle, while body elevation is primarily driven by the ankle. Steeper jumps are achieved by increased thrust at the hip and ankle and greater downward rotation of the distal limb segments. Because of its proximity to the GRF vector, knee posture appears to be important in controlling torque directions about this joint and, potentially, torque magnitudes at more distal joints. Other factors correlated with higher jump angles include increased body angle in the preparatory phase, faster joint openings and increased joint excursion, higher ventrally directed force, and greater acceleration and velocity. Finally, we demonstrate that jumping performance in K. maculata does not appear to be compromised by presumed adaptation to walking/running. Our results provide new insights into how frogs engage in a wide range of locomotor behaviours and the multi-functionality of anuran limbs