2,891 research outputs found
OrangFACS: a muscle-based facial movement coding system for orangutans (Pongo spp.)
Comparing homologous expressions between species can shed light on the phylogenetic and functional changes that have taken place during evolution. To assess homology across species we must approach primate facial expressions in an anatomical, systematic, and standardized way. The Facial Action Coding System (FACS), a widely used muscle-based tool for analyzing human facial expressions, has recently been adapted for chimpanzees (Pan troglodytes: ChimpFACS), rhesus macaques (Macaca mulatta: MaqFACS), and gibbons (GibbonFACS). Here, we present OrangFACS, a FACS adapted for orangutans (Pongo spp.). Orangutans are the most arboreal and the least social great ape, so their visual communication has been assumed to be less important than vocal communication and is little studied. We scrutinized the facial anatomy of orangutans and coded videos of spontaneous orangutan behavior to identify independent movements: Action Units (AUs) and Action Descriptors (ADs). We then compared these facial movements with movements of homologous muscles in humans, chimpanzees, macaques, and gibbons. We also noted differences related to sexual dimorphism and developmental stages in orangutan facial morphology. Our results show 17 AUs and 7 ADs in orangutans, indicating an overall facial mobility similar to that found in chimpanzees, macaques, and gibbons but smaller than that found in humans. This facial movement capacity in orangutans may be the result of several, nonmutually exclusive explanations, including the need for facial communication in specialized contexts, phylogenetic inertia, and allometric effects
Fire and climate: contrasting pressures on tropical Andean timberline species
Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA Geography, College of Life & Environmental Sciences; University of Exeter; Exeter UK Department of Biological Sciences; Florida Institute of Technology; Melbourne FL USA CEPSAR; The Open University; Milton Keynes UK Instituto de Geología; Universidad Nacional Autónoma de México; Ciudad Universitaria; Mexico City Mexico Department of Forest and Soil Sciences; University of Natural Resources and Life Sciences Vienna; Vienna Austria Department of Biology and Center for Energy; Environment and Sustainability; Wake Forest University; Winston Salem NC USACopyright © 2015 John Wiley & Sons Ltd.Aim: The aim was to test competing hypotheses regarding migration of the Andean timberline within the last 2000 years.
Location: The upper forest limit in Manu National Park, Peru.
Methods: A randomized stratified design provided 21 soil profiles from forested sites just below the timberline, 15 from puna grassland sites just above the timberline and 15 from the transitional habitat at the puna–forest boundary. From each profile a surface sample (hereafter modern) and a sample from the base of the organic horizon (hereafter historical) were collected. Pollen and charcoal were analysed from the modern and historical layers of the 51 soil profiles. A chronological framework was provided by 24 14C dates. Data were ordinated as modern and historical groups and the temporal trends illustrated by Procrustes rotation.
Results: The organic layer from the soil profiles represented the last 600–2000 years. Fire was much more abundant in all habitat types (puna, transitional and forested) in the modern compared with the historical groups. Samples that had historically been in puna just above the timberline showed encroachment by woody species. Samples that had been forested were still classified as forest but their composition had become more transitional. Sites that were transitional appeared to represent a new or expanded class of sites that was far less abundant historically.
Main conclusions: Our results are consistent with ongoing warming causing an upslope migration of species, although not necessarily of the timberline. Weedy fire-tolerant species are spreading upslope, creating a transitional forest, softening the boundary between forest and puna. Simultaneously, fire introduced to improve grazing outside the park has increasingly penetrated the forest and is causing the upper timberline to shift towards more fire-tolerant and weedy species. Consequently, both the form of the ecotone between forest and grassland and the species composition of these forests is changing and is expected to continue to change, representing a shifting baseline for what is considered to be natural.Gordon and Betty Moore Foundation Andes-to-Amazon programmeBlue Moon FundNational Science Foundatio
Optical parametric oscillation with distributed feedback in cold atoms
There is currently a strong interest in mirrorless lasing systems, in which
the electromagnetic feedback is provided either by disorder (multiple
scattering in the gain medium) or by order (multiple Bragg reflection). These
mechanisms correspond, respectively, to random lasers and photonic crystal
lasers. The crossover regime between order and disorder, or correlated
disorder, has also been investigated with some success. Here, we report
one-dimensional photonic-crystal lasing (that is, distributed feedback lasing)
with a cold atom cloud that simultaneously provides both gain and feedback. The
atoms are trapped in a one-dimensional lattice, producing a density modulation
that creates a strong Bragg reflection with a small angle of incidence. Pumping
the atoms with auxiliary beams induces four-wave mixing, which provides
parametric gain. The combination of both ingredients generates a mirrorless
parametric oscillation with a conical output emission, the apex angle of which
is tunable with the lattice periodicity
Transcriptional activation of endothelial cells by TGFβ coincides with acute microvascular plasticity following focal spinal cord ischaemia/reperfusion injury
Microvascular dysfunction, loss of vascular support, ischaemia and sub-acute vascular instability in surviving blood vessels contribute to secondary injury following SCI (spinal cord injury). Neither the precise temporal profile of the cellular dynamics of spinal microvasculature nor the potential molecular effectors regulating this plasticity are well understood. TGFβ (transforming growth factor β) isoforms have been shown to be rapidly increased in response to SCI and CNS (central nervous system) ischaemia, but no data exist regarding their contribution to microvascular dysfunction following SCI. To examine these issues, in the present study we used a model of focal spinal cord ischaemia/reperfusion SCI to examine the cellular response(s) of affected microvessels from 30 min to 14 days post-ischaemia. Spinal endothelial cells were isolated from affected tissue and subjected to focused microarray analysis of TGFβ-responsive/related mRNAs 6 and 24 h post-SCI. Immunohistochemical analyses of histopathology show neuronal disruption/loss and astroglial regression from spinal microvessels by 3 h post-ischaemia, with complete dissolution of functional endfeet (loss of aquaporin-4) by 12 h post-ischaemia. Coincident with this microvascular plasticity, results from microarray analyses show 9 out of 22 TGFβ-responsive mRNAs significantly up-regulated by 6 h post-ischaemia. Of these, serpine 1/PAI-1 (plasminogen-activator inhibitor 1) demonstrated the greatest increase (>40-fold). Furthermore, uPA (urokinase-type plasminogen activator), another member of the PAS (plasminogen activator system), was also significantly increased (>7.5-fold). These results, along with other select up-regulated mRNAs, were confirmed biochemically or immunohistochemically. Taken together, these results implicate TGFβ as a potential molecular effector of the anatomical and functional plasticity of microvessels following SCI
A scalable neural network architecture for self-supervised tomographic image reconstruction
We present a lightweight and scalable artificial neural network architecture which is used to reconstruct a tomographic image from a given sinogram. A self-supervised learning approach is used where the network iteratively generates an image that is then converted into a sinogram using the Radon transform; this new sinogram is then compared with the sinogram from the experimental dataset using a combined mean absolute error and structural similarity index measure loss function to update the weights of the network accordingly. We demonstrate that the network is able to reconstruct images that are larger than 1024 × 1024. Furthermore, it is shown that the new network is able to reconstruct images of higher quality than conventional reconstruction algorithms, such as the filtered back projection and iterative algorithms (SART, SIRT, CGLS), when sinograms with angular undersampling are used. The network is tested with simulated data as well as experimental synchrotron X-ray micro-tomography and X-ray diffraction computed tomography data
Cardiac Tissue Engineering: Implications for Pediatric Heart Surgery
Children with severe congenital malformations, such as single-ventricle anomalies, have a daunting prognosis. Heart transplantation would be a therapeutic option but is restricted due to a lack of suitable donor organs and, even in case of successful heart transplantation, lifelong immune suppression would frequently be associated with a number of serious side effects. As an alternative to heart transplantation and classical cardiac reconstructive surgery, tissue-engineered myocardium might become available to augment hypomorphic hearts and/or provide new muscle material for complex myocardial reconstruction. These potential applications of tissue engineered myocardium will, however, impose major challenges to cardiac tissue engineers as well as heart surgeons. This review will provide an overview of available cardiac tissue-engineering technologies, discuss limitations, and speculate on a potential application of tissue-engineered heart muscle in pediatric heart surgery
Neuroinflammation and structural injury of the fetal ovine brain following intra-amniotic Candida albicans exposure.
BackgroundIntra-amniotic Candida albicans (C. Albicans) infection is associated with preterm birth and high morbidity and mortality rates. Survivors are prone to adverse neurodevelopmental outcomes. The mechanisms leading to these adverse neonatal brain outcomes remain largely unknown. To better understand the mechanisms underlying C. albicans-induced fetal brain injury, we studied immunological responses and structural changes of the fetal brain in a well-established translational ovine model of intra-amniotic C. albicans infection. In addition, we tested whether these potential adverse outcomes of the fetal brain were improved in utero by antifungal treatment with fluconazole.MethodsPregnant ewes received an intra-amniotic injection of 10(7) colony-forming units C. albicans or saline (controls) at 3 or 5 days before preterm delivery at 0.8 of gestation (term ~ 150 days). Fetal intra-amniotic/intra-peritoneal injections of fluconazole or saline (controls) were administered 2 days after C. albicans exposure. Post mortem analyses for fungal burden, peripheral immune activation, neuroinflammation, and white matter/neuronal injury were performed to determine the effects of intra-amniotic C. albicans and fluconazole treatment.ResultsIntra-amniotic exposure to C. albicans caused a severe systemic inflammatory response, illustrated by a robust increase of plasma interleukin-6 concentrations. Cerebrospinal fluid cultures were positive for C. albicans in the majority of the 3-day C. albicans-exposed animals whereas no positive cultures were present in the 5-day C. albicans-exposed and fluconazole-treated animals. Although C. albicans was not detected in the brain parenchyma, a neuroinflammatory response in the hippocampus and white matter was seen which was characterized by increased microglial and astrocyte activation. These neuroinflammatory changes were accompanied by structural white matter injury. Intra-amniotic fluconazole reduced fetal mortality but did not attenuate neuroinflammation and white matter injury.ConclusionsIntra-amniotic C. albicans exposure provoked acute systemic and neuroinflammatory responses with concomitant white matter injury. Fluconazole treatment prevented systemic inflammation without attenuating cerebral inflammation and injury
- …