403 research outputs found

    Linking the proximal tibiofibular joint to hominid locomotion: A morphometric study of extant species

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    Objectives: We perform a comparative assessment of shape variation of the proximal fibula in extant humans and great apes, intending to investigate the possible link between proximal fibular shape and locomotor patterns.Methods: Our sample includes 94 fibulae of 37 Homo sapiens, 15 Gorilla, 17 Pongo, and 25 Pan. Fibular morphology was investigated through three-dimensional (semi)landmark-based geometric morphometric methods.Results: We found unique features of the human fibular head compared to that of great apes (i.e., oblique articular surface, the presence of the styloid process, specific morphology of muscle attachment sites), supporting the functional role of this bone in relation to human obligate bipedalism. Great apes also showed distinctive traits in their proximal fibula morphology, in agreement with differences in locomotor behavior.Conclusion: The morphology of the proximal fibula in extant humans and great apes is indicative of locomotor behavior, offering the potential for the comparative analysis of fossil hominin remains

    Feulgen-DNA Content and C-Banding of Robertsonian Transformed Karyotypes in Dugesia Lugubris

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    SUMMARYIn the planarian species, Dugesia lugubris, two biotypes are found: E (2n = 8, n = 4) and F (2n = 6, n = 3); on the basis of karyometric studies it has been hypothesized that the second was derived from the first through a Robert-sonian mechanism of centric fusion. The quantitative cytochemical data reported here confirm the hypothesis of karyotype evolution, since there are no significant differences between the DNA content of the nucleus in the two biotypes. The regenerative blastemas of both biotypes contain a number of cellular populations with a variable Feulgen-DNA content; these correspond to successive doublings of the 2C diploid content. In addition, metaphase plates with multistranded chromosomes have been found. A difference between the chromosome C-banding in the two biotypes has also been observed

    Old subjects with sepsis in the emergency department: Trend analysis of case fatality rate

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    Background: The burden of sepsis represents a global health care problem. We aimed to assess the case fatality rate (CFR) and its predictors in subjects with sepsis admitted to a general Italian hospital from 2009 to 2016, stratified by risk score. Methods: We performed a retrospective analysis of all sepsis-related hospitalizations after Emergency Department (ED) visit in a public Italian hospital in an 8-year period. A risk score to predict CFR was computed by logistic regression analysis of selected variables in a training set (2009-2012), and then confirmed in the whole study population. A trend analysis of CFR during the study period was performed dividing patient as high-risk (upper tertile of risk score) or low-risk. Results: Two thousand four hundred ninety-two subjects were included. Over time the incidental admission rate (no. of sepsis-related admissions per 100 total admissions) increased from 4.1% (2009-2010) to 5.4% (2015-2016); P < 0.001, accompanied by a reduced CFR (from 38.0 to 18.4%; P < 0.001). A group of 10 variables (admission to intensive care unit, cardio-vascular dysfunction, HIV infection, diabetes, age 65 80 years, respiratory diseases, number of organ dysfunction, digestive diseases, dementia and cancer) were selected by the logistic model to predict CFR with good accuracy: AUC 0.873 [0.009]. Along the years CFR decreased from 31.8% (2009-2010) to 25.0% (2015-2016); P = 0.007. The relative proportion of subjects 6580 years (overall, 52.9% of cases) and classified as high-risk did not change along the years. CFR decreased only in low-risk subjects (from 13.3 to 5.2%; P < 0.001), and particularly in those aged 6580 (from 18.2 to 6.6%; P = 0.003), but not in high-risk individuals (from 69.9 to 64.2%; P = 0.713). Conclusion: Between 2009 and 2016 the incidence of sepsis-related hospitalization increased in a general Italian hospital, with a downward trend in CFR, only limited to low-risk patients and particularly to subjects 6580 years

    The cranial biomechanics and feeding performance ofHomo floresiensis

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    Homo floresiensis is a small-bodied hominin from Flores, Indonesia, that exhibits plesiomorphic dentognathic features, including large premolars and a robust mandible, aspects of which have been considered australopith-like. However, relative to australopith species, H. floresiensis exhibits reduced molar size and a cranium with diminutive midfacial dimensions similar to those of later Homo, suggesting a reduction in the frequency of forceful biting behaviours. Our study uses finite-element analysis to examine the feeding biomechanics of the H. floresiensis cranium. We simulate premolar (P3) and molar (M2) biting in a finite-element model (FEM) of the H. floresiensis holotype cranium (LB1) and compare the mechanical results with FEMs of chimpanzees, modern humans and a sample of australopiths (MH1, Sts 5, OH5). With few exceptions, strain magnitudes in LB1 resemble elevated levels observed in modern Homo. Our analysis of LB1 suggests that H. floresiensis could produce bite forces with high mechanical efficiency, but was subject to tensile jaw joint reaction forces during molar biting, which perhaps constrained maximum postcanine bite force production. The inferred feeding biomechanics of H. floresiensis closely resemble modern humans, suggesting that this pattern may have been present in the last common ancestor of Homo sapiens and H. floresiensis

    Atypical depressive syndromes in varying definitions

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    Background: Atypical depression (AD) exhibits distinct patterns of gender,bipolar-II disorder, genetic, and neuro-biological measures. Using prospective data from a community sample, this paper identifies criteria (and correlates) for an AD syndrome that maximizes the association with female sex and bipolar-II. Methods: The Zurich cohort study is composed of 591 subjects selected from a population-based cohort of young adults in the canton of Zurich in Switzerland, screened in 1978 and followed with six interviews through 1999. Seven definitions of atypical depression were tested, using varying combinations of vegetative symptoms and mood reactivity. Results: The atypical definitions using 2 of 3 (fatigue, overeating, oversleeping) or 2 of 2 (overeating, oversleeping) vegetative symptoms showed the strongest association with gender, bipolarity, and family history of mania. The 2/3 definition was chosen for further analysis due to its high sensitivity for identifying these characteristics. This syndrome had cumulated weighted prevalence of 16.4% (males 9.7%, females 23%); when associated with major depressive episodes, 8.2% (males 3.2%, females 15.1%). AD patients were characterized by high treatment rates, severity, and work impairment, early age of onset and long illness. AD was comorbid with social phobia, binge eating, neurasthenia, migraine headache, and subjective cognitive impairmen

    3D enamel thickness in Neandertal and modern human permanent canines

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    Enamel thickness figures prominently in studies of human evolution, particularly for taxonomy, phylogeny, and paleodietary reconstruction. Attention has focused on molar teeth, through the use of advanced imaging technologies and novel protocols. Despite the important results achieved thus far, further work is needed to investigate all tooth classes. We apply a recent approach developed for anterior teeth to investigate the 3D enamel thickness of Neandertal and modern human (MH) canines. In terms of crown size, the values obtained for both upper and lower unworn/slightly worn canines are significantly greater in Neandertals than in Upper Paleolithic and recent MH. The 3D relative enamel thickness (RET) is significantly lower in Neandertals than in MH. Moreover, differences in 3D RET values between the two groups appear to decrease in worn canines beginning from wear stage 3, suggesting that both the pattern and the stage of wear may have important effects on the 3D RET value. Nevertheless, the 3D average enamel thickness (AET) does not differ between the two groups. In both groups, 3D AET and 3D RET indices are greater in upper canines than in lower canines, and overall the enamel is thicker on the occlusal half of the labial aspect of the crown, particularly in MH. By contrast, the few early modern humans investigated show the highest volumes of enamel while for all other components of 3D enamel, thickness this group holds an intermediate position between Neandertals and recent MH. Overall, our study supports the general findings that Neandertals have relatively thinner enamel than MH (as also observed in molars), indicating that unworn/slightly worn canines can be successfully used to discriminate between the two groups. Further studies, however, are needed to understand whether these differences are functionally related or are the result of pleiotropic or genetic drift effects

    Buffer breakdown in GaN-on-Si HEMTs: A comprehensive study based on a sequential growth experiment

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    Abstract The aim of this work is to investigate the breakdown mechanisms of the layers constituting the vertical buffer of GaN-on-Si HEMTs; in addition, for the first time we demonstrate that the breakdown field of the AlN nucleation layer grown on a silicon substrate is equal to 3.2 MV/cm and evaluate its temperature dependence. To this aim, three samples, obtained by stopping the epitaxial growth of a GaN on Silicon stack at different steps, are studied and compared: Si/AlN, Si/AlN/AlGaN, full vertical stack up to the Carbon doped buffer layer. The current-voltage (IV) characterizations performed at both room temperature and high temperature show that: (i) the defectiveness of the AlN nucleation layer is the root cause of the leakage through an AlN/Silicon junction, and causes the vertical I-V characteristics to have a high device-to-device variability; (ii) the first AlGaN layer grown over the AlN, beside improving the breakdown voltage of the whole structure, causes the leakage current to be more stable and uniform across the sample area; (iii) a thick strain-relief stack and a carbon-doped GaN buffer enhance the breakdown voltage up to more than 750 V at 170 °C, and guarantee a remarkably low device-to-device variability. Furthermore, a set of constant voltage stress on the Si/AlN sample demonstrate that the aluminum nitride layer shows a time dependent breakdown, with Weibull-distributed failures and a shape factor greater than 1, in line with the percolation model

    Canine placenta histological findings and microvascular density: The histological basis of a negative neonatal outcome?

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    Placenta is essential for the development of the fetus, and its impaired function can lead to a negative outcome (i.e., neonatal mortality). In dogs, investigations on placenta histology and neonatal outcome in healthy bitches are lacking, and a contribution is provided in this study to emphasize the use of placenta histology in practice. Fifty-one placentas from 11 litters were collected during cesarean section, classified according to the litter size (large (L) or small (S)) and the outcome, this latter as healthy (Group 1) or dead within 7 days (Group 2). The placenta/puppy weight ratio (PPR) was calculated, and specimens were formalin-fixed and paraffin-wax embedded, and on the resulting histological slides, capillary density (CD) was quantified. Among necrosis, calcification, and intravascular leucocytes, only the presence of multifocal-confluent necrosis (significantly more frequent in Group 2) was associated with a higher risk of death within 7 days (odds ratio = 30.7). Mixed logistic regression ruled out the effect on death both of a bitch and cesarean type (programmed vs. emergency). PPR and CD values were associated with litter size; large litters had lower PPR (p < 0.01) and higher CD (p < 0.05) than small litters. The relationship between PPR and CD was negative and significant (p < 0.01). Necrosis was a frequent finding in canine placentas, but only when multifocal-confluent was it associated with a poor outcome. The litter size influenced PPR (lower in L) and CD (higher in L), and this is likely due to the plasticity of placenta adaptation

    The Ornaments of the Arma Veirana Early Mesolithic Infant Burial

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    Personal ornaments are widely viewed as indicators of social identity and personhood. Ornaments are ubiquitous from the Late Pleistocene to the Holocene, but they are most often found as isolated objects within archaeological assemblages without direct evidence on how they were displayed. This article presents a detailed record of the ornaments found in direct association with an Early Mesolithic buried female infant discovered in 2017 at the site of Arma Veirana (Liguria, Italy). It uses microscopic, 3D, and positional analyses of the ornaments as well as a preliminary perforation experiment to document how they were perforated, used, and what led to their deposit as part of the infant’s grave goods. This study provides important information on the use of beads in the Early Mesolithic, in general, as well as the relationship between beads and young subadults, in particular. The results of the study suggest that the beads were worn by members of the infant’s community for a considerable period before they were sewn onto a sling, possibly used to keep the infant close to the parents while allowing their mobility, as seen in some modern forager groups. The baby was then likely buried in this sling to avoid reusing the beads that had failed to protect her or simply to create a lasting connection between the deceased infant and her community.Funding was provided by the Wenner-Gren Foundation (#9412), L.S.B. Leakey Foundation, National Geographic Society Waitt Program (#W391-15), Hyde Family Foundation [via the Human Origins Migrations and Evolutionary Research (HOMER) consortium], Social Sciences and Humanities Research Council (SSHRC) Insight Development Grant (#430–2018-00846), University of Colorado Denver, Washington University in St. Louis, Université de Montréal, and ERC n. 724046 – SUCCESS (to S.B.; http://www.erc-success.eu/). Part of the ornament analysis was supported by the European Research Council under the European Union’s Horizon 2020 Research and Innovation Program (grant agreement no. 639286 HIDDEN FOODS to E.C; http://www.hidden-foods.eu) to E.C. CHEI (University of California San Diego) supported 3D imaging. S. Talamo has received funding from the European Research Council under the European Union’s Horizon 2020 Research and Innovation Programme (grant agreement no. 803147 RESOLUTION, https://site.unibo.it/resolution-erc/en). The micro-CT scans have been co-funded by EuroBioimaging, Italian Multi-sited Multi-modal Molecular Imaging (MMMI) Node, application n.EuBI_FANE130
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