482 research outputs found

    Social rank overrides environmental and community fluctuations in determining meat access by female chimpanzees in the Taï National Park, Côte d’Ivoire

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    Meat, long hypothesized as an important food source in human evolution, is still a substantial component of the modern human diet, with some humans relying entirely on meat during certain times of the year. Understanding the socio-ecological context leading to the successful acquisition and consumption of meat by chimpanzees (Pan troglodytes), our closest living relative, can provide insight into the emergence of this trait because humans and chimpanzees are unusual among primates in that they both (i) hunt mammalian prey, (ii) share meat with community members, and (iii) form long-term relationships and complex social hierarchies within their communities. However, females in both human hunter-gatherer societies as well as chimpanzee groups rarely hunt, instead typically accessing meat via males that share meat with group members. In general, female chimpanzee dominance rank affects feeding competition, but so far, the effect of female dominance rank on meat access found different results within and across studied chimpanzee groups. Here we contribute to the debate on how female rank influences meat access while controlling for several socio-ecological variables. Multivariate analyses of 773 separate meat-eating events collected over more than 25 years from two chimpanzee communities located in the Taï National Park, Côte d’Ivoire, were used to test the importance of female dominance rank for being present at, and for acquiring meat, during meat-eating events. We found that high-ranking females were more likely to be present during a meat-eating event and, in addition, were more likely to eat meat compared to the subordinates. These findings were robust to both large demographic changes (decrease of community size) and seasonal ecological changes (fruit abundance dynamics). In addition to social rank, we found that other female properties had a positive influence on presence to meat-eating events and access to meat given presence, including oestrus status, nursing of a small infant, and age. Similar to findings in other chimpanzee populations, our results suggest that females reliably acquire meat over their lifetime despite rarely being active hunters. The implication of this study supports the hypothesis that dominance rank is an important female chimpanzee property conferring benefits for the high-ranking females

    Implementation issues in chemistry and transport models

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    International audienceOffline chemistry and transport models (CTMs) are versatile tools for studying composition and climate issues requiring multi-decadal simulations. They are computationally fast compared to coupled chemistry climate models, making them well-suited for integrating sensitivity experiments necessary for understanding model performance and interpreting results. The archived meteorological fields used by CTMs can be implemented with lower horizontal or vertical resolution than the original meteorological fields in order to shorten integration time, but the effects of these shortcuts on transport processes must be understood if the CTM is to have credibility. In this paper we present a series of CTM experiments, each differing from another by a single feature of the implementation. Transport effects arising from changes in resolution and model lid height are evaluated using process-oriented diagnostics that intercompare CH4, O3, and age tracer carried in the simulations. Some of the diagnostics used are derived from observations and are shown as a reality check for the model. Processes evaluated include the tropical ascent, tropical-midlatitude exchange, the poleward circulation in the upper stratosphere, and the development of the Antarctic vortex. We find that faithful representation of stratospheric transport in this CTM using Lin and Rood advection is possible with a full mesosphere, ~1 km resolution in the lower stratosphere, and relatively low vertical resolution (>4 km spacing) in the middle stratosphere and above, but lowering the lid from the upper to lower mesosphere leads to less realistic constituent distributions in the upper stratosphere. Ultimately, this affects the polar lower stratosphere, but the effects are greater for the Antarctic than the Arctic. The fidelity of lower stratospheric transport requires realistic tropical and high latitude mixing barriers which are produced at 2°×2.5°, but not lower resolution. At 2°×2.5° resolution, the CTM produces a vortex capable of isolating perturbed chemistry (e.g. high Cly and low NOy) required for simulating polar ozone loss

    Experimental Evaluation of Dual-Modality Electrical Tomographic Systems on Gas-Oil-Water Flow in Horizontal Pipeline

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    A variety of dual-modality tomographic systems have been proposed for the characterisation of multiphase flow, but the evaluation of such systems are generally carried out under simplified flow conditions, such as stratified flow and slug flow. This paper reports the evaluation results of a dualmodality electrical tomographic system in an industry-scale gas-oil-water three-phase flow. Experimental conditions include water-to-liquid ratio (WLR) from 0% to 100% in parallel with gas volume fractions from 0% to 100%, which produces a variety of flow patterns, such as stratified-wavy flow, slug flow, plug flow, bubbly flow, and annular flow. Commercialised ITS M3C (ECT) and V5R (ERT) dual-modality systems were applied to perform the measurement. A threshold-based multidimensional data fused approach was implemented for the data fusion process. The results demonstrated that the ERT system is able to measure water continuous flow with WLR higher than 40%, which is in good agreement with previous reports. The ECT system is able to measure from 0% to 100% WLR, far beyond its conventional capabilities. Even though the tomograms are distorted when WLR is higher than 90%, this result is much better than the reported 40% limit. Visualisation and mean concentration derived from the tomograms by advanced data fusion verify the capability of the system in the application of gas-oil-water flow characterisation

    The Sensitivity of Arctic Ozone Loss to Polar Stratospheric Cloud Volume and Chlorine and Bromine Loading in a Chemistry and Transport Model

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    The sensitivity of Arctic ozone loss to polar stratospheric cloud volume (V(sub PSC)) and chlorine and bromine loading is explored using chemistry and transport models (CTMs). A simulation using multi-decadal output from a general circulation model (GCM) in the Goddard Space Flight Center (GSFC) CTM complements one recycling a single year s GCM output in the Global Modeling Initiative (GMI) CTM. Winter polar ozone loss in the GSFC CTM depends on equivalent effective stratospheric chlorine (EESC) and polar vortex characteristics (temperatures, descent, isolation, polar stratospheric cloud amount). Polar ozone loss in the GMI CTM depends only on changes in EESC as the dynamics repeat annually. The GSFC CTM simulation reproduces a linear relationship between ozone loss and Vpsc derived from observations for 1992 - 2003 which holds for EESC within approx.85% of its maximum (approx.1990 - 2020). The GMI simulation shows that ozone loss varies linearly with EESC for constant, high V(sub PSC)

    The Causal Structure of Emotions in Aristotle: Hylomorphism, Causal Interaction between Mind and Body, and Intentionality

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    Recently, a strong hylomorphic reading of Aristotelian emotions has been put forward, one that allegedly eliminates the problem of causal interaction between soul and body. Taking the presentation of emotions in de An. I 1 as a starting point and basic thread, but relying also on the discussion of Rh. II, I will argue that this reading only takes into account two of the four causes of emotions, and that, if all four of them are included into the picture, then a causal interaction of mind and body remains within Aristotelian emotions, independent of how strongly their hylomorphism is understood. Beyond the discussion with this recent reading, the analysis proposed of the fourfold causal structure of emotions is also intended as a hermeneutical starting point for a comprehensive analysis of particular emotions in Aristotle. Through the different causes Aristotle seems to account for many aspects of the complex phenomenon of emotion, including its physiological causes, its mental causes, and its intentional object

    A bimodal spacecraft bus based on a cermet fueled heat pipe reactor

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    Bimodal space reactor systems provide both thermal propulsion for the spacecraft orbital transfer and electrical power to the spacecraft bus once it is on station. These systems have the potential to increase both the available payload in high energy orbits and the available power to that payload. These increased mass and power capabilities can be used to either reduce mission cost by permitting the use of smaller launch vehicles or to provide increased mission performance from the current launch vehicle. A major barrier to the deployment of these bimodal systems has been the cost associated with their development. This paper describes a bimodal spacecraft bus with performance potential to permit more than 70% of the instrumented payload of the Titan IV/Centaur to be launched from the Atlas IIAS. The development cost is minimized by basing the design on existing component technologies

    Capability of dual-modality electrical tomography for gas-oil-water three-phase pipeline flow visualisation

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    Numerous dual-modality tomography systems have previously been studied for multiphase flow characterisation, however, the capability of the majority of these systems was only demonstrated under limited flow regime conditions, such as stratified flow and slug flow. This paper reports a dual-modality electrical tomography for visualisation of industrial-scale, horizontal gas-oil-water three-phase flows. Experimental conditions include water-to-liquid ratio (WLR) from 0% to 100% in parallel with gas volume fractions (GVF) from 0% to 100%, which produced a variety of flow patterns, typically stratified flow, slug flow, plug flow, bubbly flow, and annular flow. A commercial dual-modality electrical tomographic system was utilised to carry out the measurement. A threshold-based data fusion method was also deployed for the fusion of oil-continuous and water-continuous data to provide full three phase images. The tomography visualisation is validated against optical photographs derived from a high-speed video logger located one diameter upstream of the device. The results demonstrate that a subcomponent of the dual modality sensor, an electrical resistance tomography (ERT) system, is able to visualise water continuous flow with WLR higher than 40%, providing good agreement with previous reports. The remaining subcomponent, the electrical capacitance tomography (ECT) system, is able to provide stable measurement during WLR from 0% to 90%, which is far beyond initial expectations and previous findings. Mean concentrations measured with the dual-modality system reveal the potential capability of the tomography system for phase fraction measurement. The visualisation results with the advanced data fusion method and mean concentration measurement verify the capability of the system in the application of gas-oil-water flow characterisation

    Expression and DNA methylation of TNF, IFNG and FOXP3 in colorectal cancer and their prognostic significance.

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    BACKGROUND: Colorectal cancer (CRC) progression is associated with suppression of host cell-mediated immunity and local immune escape mechanisms. Our aim was to assess the immune function in terms of expression of TNF, IFNG and FOXP3 in CRC. METHODS: Sixty patients with CRC and 15 matched controls were recruited. TaqMan quantitative PCR and methylation-specific PCR was performed for expression and DNA methylation analysis of TNF, IFNG and FOXP3. Survival analysis was performed over a median follow-up of 48 months. RESULTS: TNF was suppressed in tumour and IFNG was suppressed in peripheral blood mononuclear cells (PBMCs) of patients with CRC. Tumours showed enhanced expression of FOXP3 and was significantly higher when tumour size was >38 mm (median tumour size; P=0.006, Mann-Whitney U-test). Peripheral blood mononuclear cell IFNG was suppressed in recurrent CRC (P=0.01). Methylated TNFpromoter (P=0.003) and TNFexon1 (P=0.001) were associated with significant suppression of TNF in tumours. Methylated FOXP3cpg was associated with significant suppression of FOXP3 in both PBMC (P=0.018) and tumours (P=0.010). Reduced PBMC FOXP3 expression was associated with significantly worse overall survival (HR=8.319, P=0.019). CONCLUSIONS: We have detected changes in the expression of immunomodulatory genes that could act as biomarkers for prognosis and future immunotherapeutic strategies
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