192 research outputs found
Nature and relationships of Sahelanthropus tchadensis
A partial left femur (TM 266-01-063) was recovered in July 2001 at Toros-Menalla, Chad, at the same fossiliferous location as the late Miocene holotype of Sahelanthropus tchadensis (the cranium TM 266-01-060-1). It was recognized as a probable primate femur in 2004 when one of the authors was undertaking a taphonomic survey of the fossil assemblages from Toros-Menalla. We are confident the TM 266 femoral shaft belongs to a hominid. It could sample a hominid hitherto unrepresented at Toros-Menalla, but a more parsimonious working hypothesis is that it belongs to S. tchadensis. The differences between TM 266 and the late Miocene Orrorin tugenensis partial femur BAR 1002âČ00, from Kenya, are consistent with maintaining at least a species-level distinction between S. tchadensis and O. tugenensis. The results of our preliminary functional analysis suggest the TM 266 femoral shaft belongs to an individual that was not habitually bipedal, something that should be taken into account when considering the relationships of S. tchadensis. The circumstances of its discovery should encourage researchers to check to see whether there is more postcranial evidence of S. tchadensis among the fossils recovered from Toros-Menalla
Towards an understanding of credit cycles: do all credit booms cause crises?
Macroprudential policy is now based around a countercyclical buffer, relating capital
requirements for banks to the degree of excess credit in the economy. We consider the
construction of the credit to GDP gap looking at different ways of extracting the cyclical
indicator for excess credit. We compare different smoothing mechanisms for the credit
gap, and demonstrate that some countries require an AR(2) smoother whilst other do
not. We embed these different estimates of the credit gap in Logit models of financial
crises, and show that the AR(2) cycle is a much better contributor to their explanation
than is the HP filter suggested by the BIS and currently in use in policy making.Weshow
that our results are robust to changes in assumptions, and we make criticisms of current
policy settings
Growth and development of the third permanent molar in Paranthropus robustus from Swartkrans, South Africa
Third permanent molars (M3s) are the last tooth to form but have not been used to estimate age at dental maturation in early fossil hominins because direct histological evidence for the timing of their growth has been lacking. We investigated an isolated maxillary M3 (SK 835) from the 1.5 to 1.8-million-year-old (Mya) site of Swartkrans, South Africa, attributed to Paranthropus robustus. Tissue proportions of this specimen were assessed using 3D X-ray micro-tomography. Thin ground sections were used to image daily growth increments in enamel and dentine. Transmitted light microscopy and synchrotron X-ray fluorescence imaging revealed fluctuations in Ca concentration that coincide with daily growth increments. We used regional daily secretion rates and Sr marker-lines to reconstruct tooth growth along the enamel/dentine and then cementum/dentine boundaries. Cumulative growth curves for increasing enamel thickness and tooth height and age-of-attainment estimates for fractional stages of tooth formation differed from those in modern humans. These now provide additional means for assessing late maturation in early hominins. M3 formation tookââ„â7 years in SK 835 and completion of the roots would have occurred between 11 and 14 years of age. Estimated age at dental maturation in this fossil hominin compares well with what is known for living great apes
Reassessment of the TM 1517 odonto-postcranial assemblage from Kromdraai B, South Africa, and the maturational pattern of Paranthropus robustus
Objectives
The Pleistocene taxon Paranthropus robustus was established in 1938 following the discovery at Kromdraai B, South Africa, of the partial cranium TM 1517a and associated mandible TM 1517b. Shortly thereafter, a distal humerus (TM 1517g), a proximal ulna (TM 1517e), and a distal hallucial phalanx (TM 1517k) were collected nearby at the site, and were considered to be associated with the holotype. TM 1517aâb represents an immature individual; however, no analysis of the potentially associated postcranial elements has investigated the presence of any endostructural remnant of recent epiphyseal closure. This study aims at tentatively detecting such traces in the three postcranial specimens from Kromdraai B.
Materials and Methods
By using ÎŒXCT techniques, we assessed the developmental stage of the TM 1517b's CâM3 roots and investigated the inner structure of TM 1517g, TM 1517e, and TM 1517k.
Results
The M2 shows incompletely closed root apices and the M3 a halfâcompleted root formation stage. The distal humerus was likely completely fused, while the proximal ulna and the distal hallucial phalanx preserve endosteal traces of the diaphyseoâepiphyseal fusion process.
Discussion
In the hominin fossil record, there are few unambiguously associated craniodental and postcranial remains sampling immature individuals, an essential condition for assessing the taxonâspecific maturational patterns. Our findings corroborate the original association of the craniodental and postcranial remains representing the P. robustus type specimen. As with other PlioâPleistocene hominins, the odontoâpostcranial maturational pattern of TM 1517 more closely fits an African great ape rather than the extant human pattern
Activity of Antioxidants from Crocus sativus L. Petals: Potential Preventive Effects towards Cardiovascular System
The petals of the saffron crocus (Crocus sativus L.) are considered a waste material in saffron production, but may be a sustainable source of natural biologically active substances of nutraceutical interest. The aim of this work was to study the cardiovascular effects of kaempferol and crocin extracted from saffron petals. The antiarrhythmic, inotropic, and chronotropic effects of saffron petal extract (SPE), kaempferol, and crocin were evaluated through in vitro biological assays. The antioxidant activity of kaempferol and crocin was investigated through the 2',7'-dichlorodihydrofluorescein diacetate (DCFH-DA) assay using rat cardiomyoblast cell line H9c2. The MTT assay was applied to assess the effects of kaempferol and crocin on cell viability. SPE showed weak negative inotropic and chronotropic intrinsic activities but a significant intrinsic activity on smooth muscle with a potency on the ileum greater than on the aorta: EC50 = 0.66 mg/mL versus EC50 = 1.45 mg/mL. Kaempferol and crocin showed a selective negative inotropic activity. In addition, kaempferol decreased the contraction induced by KCl (80 mM) in guinea pig aortic and ileal strips, while crocin had no effect. Furthermore, following oxidative stress, both crocin and kaempferol decreased intracellular ROS formation and increased cell viability in a concentration-dependent manner. The results indicate that SPE, a by-product of saffron cultivation, may represent a good source of phytochemicals with a potential application in the prevention of cardiovascular diseases
New Hydrogels Enriched with Antioxidants from Saffron Crocus Can Find Applications in Wound Treatment and/or Beautification
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkSaffron extracts have a long history of application as skin protectant, possibly due to their ability to scavenge free radicals. In this work, the performance of a hydrogel enriched with antioxidant compounds isolated from saffron crocus (Crocus sativus L.) petals was tested. These hydrogels could be considered as new drug delivery system. Hydrogels are crosslinked polymer networks that absorb large quantities of water but retain the properties of a solid, thus making ideal dressings for sensitive skin. We tested antioxidant-en- riched hydrogels on primary mouse fibroblasts. Hydrogels enriched with kaempferol and crocin extracted from saffron petals showed good biocompatibility with in vitro cultured fibroblasts. These new types of hydrogels may find applications in wound treatment and/or beautification
Is the deciduous/permanent molar enamel thickness ratio a taxon-specific indicator in extant and extinct hominids?
In Primates, enamel thickness variation stems from an evolutionary interplay between functional/adaptive constraints (ecology) and the strict control mechanisms of the morphogenetic program. Most studies on primate enamel thickness have primarily considered the permanent teeth, while the extent of covariation in tooth enamel thickness distribution between deciduous and permanent counterparts remains poorly investigated. In this test study on nine extant and fossil hominids we investigated the degree of covariation in enamel proportions between 25 pairs of mandibular dm2 and M1 by a so-called âlateral enamel thickness diphyodontic indexâ. The results did not provide an unambiguous picture, but rather suggest complex patterns likely resulting from the influence of many interactive factors. Future research should test the congruence of the âdiphyodontic signalâ between the anterior and the postcanine dentition, as well as between enamel and the enamel-dentine junction topography
Morphology on the cloud Virtual Campus, an integrated didactic platform for biomedical studies
The current Core Curricula of Degree courses in Biomedical areas has enormously compressed the hours dedicated to the student for self-learning in morphological subjects. The result is a reduced student attitude to integrate the information received by attending lectures and practical sessions, with the indispensable consultation of texts dealing with morphological and \u2018functional\u2019 subjects, a key experience to autonomously logically identify the rational of the morphology/function relationship in the human body, at the macroscopic and microscopic level. These changes are occurring at a time when new medical imaging technologies become more and more informative in both morphological and functional areas. As a consequence, we are modifying our way of organize lessons compared to the generations of colleagues who have preceded us. More and more frontal lessons are organized with a logical morpho-functional approach. For example, the reference to the anatomy of the living, displayed through invasive or not invasive imaging, is added to the necessary and traditional anatomy of the cadaver. The reference to the pathology helps to define how the alteration of morphological integrity is reflected on function, both at the macro and microscopic level, and so on. However, there are no organized easy-to-use guided tours for the student to allow, in the shortest possible time, to \u2018rationally see\u2019 what he has studied, in the various imaging contexts available at the macro- and microscopic level. At the same time, there are no \u2018data bank\u2019 of resources for the preparation of the lessons. That is why we have imagined \u2018virtual campus\u2019 an integrated digital learning platform for self-learning. The platform has been thought and realized thanks to a group of teachers of \u2018morphologic\u2019 and \u2018functional\u2019 biomedical subjects and computer engineers belonging to a publishing house. The presentation will explain the rationale behind the platform, its structure and the educational opportunities offered
Under the Skin of a Lion: Unique Evidence of Upper Paleolithic Exploitation and Use of Cave Lion (Panthera spelaea) from the Lower Gallery of La Garma (Spain)
ABSTRACT: Pleistocene skinning and exploitation of carnivore furs have been previously inferred from archaeological evidence. Nevertheless, the evidence of skinning and fur processing tends to be weak and the interpretations are not strongly sustained by the archaeological record. In the present paper, we analyze unique evidence of patterned anthropic modification and skeletal representation of fossil remains of cave lion (Panthera spelaea) from the Lower Gallery of La Garma (Cantabria, Spain). This site is one of the few that provides Pleistocene examples of lion exploitation by humans. Our archaeozoological study suggests that lion-specialized pelt exploitation and use might have been related to ritual activities during the Middle Magdalenian period (ca. 14800 cal BC). Moreover, the specimens also represent the southernmost European and the latest evidence of cave lion exploitation in Iberia. Therefore, the study seeks to provide alternative explanations for lion extinction in Eurasia and argues for a role of hunting as a factor to take into account
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