19 research outputs found

    Adaptive bill morphology for enhanced tool manipulation in New Caledonian crows

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    Early increased sophistication of human tools is thought to be underpinned by adaptive morphology for efficient tool manipulation. Such adaptive specialisation is unknown in nonhuman primates but may have evolved in the New Caledonian crow, which has sophisticated tool manufacture. The straightness of its bill, for example, may be adaptive for enhanced visually-directed use of tools. Here, we examine in detail the shape and internal structure of the New Caledonian crow’s bill using Principal Components Analysis and Computed Tomography within a comparative framework. We found that the bill has a combination of interrelated shape and structural features unique within Corvus, and possibly birds generally. The upper mandible is relatively deep and short with a straight cutting edge, and the lower mandible is strengthened and upturned. These novel combined attributes would be functional for (i) counteracting the unique loading patterns acting on the bill when manipulating tools, (ii) a strong precision grip to hold tools securely, and (iii) enhanced visually-guided tool use. Our findings indicate that the New Caledonian crow’s innovative bill has been adapted for tool manipulation to at least some degree. Early increased sophistication of tools may require the co-evolution of morphology that provides improved manipulatory skills

    What has finite element analysis taught us about diabetic foot disease and its management?:a systematic review

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    Over the past two decades finite element (FE) analysis has become a popular tool for researchers seeking to simulate the biomechanics of the healthy and diabetic foot. The primary aims of these simulations have been to improve our understanding of the foot's complicated mechanical loading in health and disease and to inform interventions designed to prevent plantar ulceration, a major complication of diabetes. This article provides a systematic review and summary of the findings from FE analysis-based computational simulations of the diabetic foot.A systematic literature search was carried out and 31 relevant articles were identified covering three primary themes: methodological aspects relevant to modelling the diabetic foot; investigations of the pathomechanics of the diabetic foot; and simulation-based design of interventions to reduce ulceration risk.Methodological studies illustrated appropriate use of FE analysis for simulation of foot mechanics, incorporating nonlinear tissue mechanics, contact and rigid body movements. FE studies of pathomechanics have provided estimates of internal soft tissue stresses, and suggest that such stresses may often be considerably larger than those measured at the plantar surface and are proportionally greater in the diabetic foot compared to controls. FE analysis allowed evaluation of insole performance and development of new insole designs, footwear and corrective surgery to effectively provide intervention strategies. The technique also presents the opportunity to simulate the effect of changes associated with the diabetic foot on non-mechanical factors such as blood supply to local tissues.While significant advancement in diabetic foot research has been made possible by the use of FE analysis, translational utility of this powerful tool for routine clinical care at the patient level requires adoption of cost-effective (both in terms of labour and computation) and reliable approaches with clear clinical validity for decision making

    Geoeconomic variations in epidemiology, ventilation management, and outcomes in invasively ventilated intensive care unit patients without acute respiratory distress syndrome: a pooled analysis of four observational studies

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    Background: Geoeconomic variations in epidemiology, the practice of ventilation, and outcome in invasively ventilated intensive care unit (ICU) patients without acute respiratory distress syndrome (ARDS) remain unexplored. In this analysis we aim to address these gaps using individual patient data of four large observational studies. Methods: In this pooled analysis we harmonised individual patient data from the ERICC, LUNG SAFE, PRoVENT, and PRoVENT-iMiC prospective observational studies, which were conducted from June, 2011, to December, 2018, in 534 ICUs in 54 countries. We used the 2016 World Bank classification to define two geoeconomic regions: middle-income countries (MICs) and high-income countries (HICs). ARDS was defined according to the Berlin criteria. Descriptive statistics were used to compare patients in MICs versus HICs. The primary outcome was the use of low tidal volume ventilation (LTVV) for the first 3 days of mechanical ventilation. Secondary outcomes were key ventilation parameters (tidal volume size, positive end-expiratory pressure, fraction of inspired oxygen, peak pressure, plateau pressure, driving pressure, and respiratory rate), patient characteristics, the risk for and actual development of acute respiratory distress syndrome after the first day of ventilation, duration of ventilation, ICU length of stay, and ICU mortality. Findings: Of the 7608 patients included in the original studies, this analysis included 3852 patients without ARDS, of whom 2345 were from MICs and 1507 were from HICs. Patients in MICs were younger, shorter and with a slightly lower body-mass index, more often had diabetes and active cancer, but less often chronic obstructive pulmonary disease and heart failure than patients from HICs. Sequential organ failure assessment scores were similar in MICs and HICs. Use of LTVV in MICs and HICs was comparable (42\ub74% vs 44\ub72%; absolute difference \u20131\ub769 [\u20139\ub758 to 6\ub711] p=0\ub767; data available in 3174 [82%] of 3852 patients). The median applied positive end expiratory pressure was lower in MICs than in HICs (5 [IQR 5\u20138] vs 6 [5\u20138] cm H2O; p=0\ub70011). ICU mortality was higher in MICs than in HICs (30\ub75% vs 19\ub79%; p=0\ub70004; adjusted effect 16\ub741% [95% CI 9\ub752\u201323\ub752]; p<0\ub70001) and was inversely associated with gross domestic product (adjusted odds ratio for a US$10 000 increase per capita 0\ub780 [95% CI 0\ub775\u20130\ub786]; p<0\ub70001). Interpretation: Despite similar disease severity and ventilation management, ICU mortality in patients without ARDS is higher in MICs than in HICs, with a strong association with country-level economic status. Funding: No funding

    Urban Form Energy Use and Emissions in China: Preliminary Findings and Model Proof of Concept

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    Urbanization is reshaping China's economy, society, and energy system. Between 1990 and 2008 China added more than 300 million new urban residents, bringing the total urbanization rate to 46%. The ongoing population shift is spurring energy demand for new construction, as well as additional residential use with the replacement of rural biomass by urban commercial energy services. This project developed a modeling tool to quantify the full energy consequences of a particular form of urban residential development in order to identify energy- and carbon-efficient modes of neighborhood-level development and help mitigate resource and environmental implications of swelling cities. LBNL developed an integrated modeling tool that combines process-based lifecycle assessment with agent-based building operational energy use, personal transport, and consumption modeling. The lifecycle assessment approach was used to quantify energy and carbon emissions embodied in building materials production, construction, maintenance, and demolition. To provide more comprehensive analysis, LBNL developed an agent-based model as described below. The model was applied to LuJing, a residential development in Jinan, Shandong Province, to provide a case study and model proof of concept. This study produced results data that are unique by virtue of their scale, scope and type. Whereas most existing literature focuses on building-, city-, or national-level analysis, this study covers multi-building neighborhood-scale development. Likewise, while most existing studies focus exclusively on building operational energy use, this study also includes embodied energy related to personal consumption and buildings. Within the boundaries of this analysis, food is the single largest category of the building energy footprint, accounting for 23% of the total. On a policy level, the LCA approach can be useful for quantifying the energy and environmental benefits of longer average building lifespans. In addition to prospective analysis for standards and certification, urban form modeling can also be useful in calculating or verifying ex post facto, bottom-up carbon emissions inventories. Emissions inventories provide a benchmark for evaluating future outcomes and scenarios as well as an empirical basis for valuing low-carbon technologies. By highlighting the embodied energy and emissions of building materials, the LCA approach can also be used to identify the most intensive aspects of industrial production and the supply chain. The agent based modeling aspect of the model can be useful for understanding how policy incentives can impact individual behavior and the aggregate effects thereof. The most useful elaboration of the urban form assessment model would be to further generalize it for comparative analysis. Scenario analysis could be used for benchmarking and identification of policy priorities. If the model is to be used for inventories, it is important to disaggregate the energy use data for more accurate emissions modeling. Depending on the policy integration of the model, it may be useful to incorporate occupancy data for per-capita results. On the question of density and efficiency, it may also be useful to integrate a more explicit spatial scaling mechanism for modeling neighborhood and city-level energy use and emissions, i.e. to account for scaling effects in public infrastructure and transportation

    Numerical Simulation of Blood Flow in an Anatomically-Accurate Cerebral Venous Tree

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    High-resolution entrainment mapping of gastric pacing: a new analytical tool

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    Gastric pacing has been investigated as a potential treatment for gastroparesis. New pacing protocols are required to improve symptom and motility outcomes; however, research progress has been constrained by a limited understanding of the effects of electrical stimulation on slow-wave activity. This study introduces high-resolution (HR) “entrainment mapping” for the analysis of gastric pacing and presents four demonstrations. Gastric pacing was initiated in a porcine model (typical amplitude 4 mA, pulse width 400 ms, period 17 s). Entrainment mapping was performed using flexible multielectrode arrays (≤192 electrodes; 92 cm2) and was analyzed using novel software methods. In the first demonstration, entrainment onset was quantified over successive waves in spatiotemporal detail. In the second demonstration, slow-wave velocity was accurately determined with HR field analysis, and paced propagation was found to be anisotropic (longitudinal 2.6 ± 1.7 vs. circumferential 4.5 ± 0.6 mm/s; P < 0.001). In the third demonstration, a dysrhythmic episode that occurred during pacing was mapped in HR, revealing an ectopic slow-wave focus and uncoupled propagations. In the fourth demonstration, differences were observed between paced and native slow-wave amplitudes (0.24 ± 0.08 vs. 0.38 ± 0.14 mV; P < 0.001), velocities (6.2 ± 2.8 vs. 11.5 ± 4.7 mm/s; P < 0.001), and activated areas (20.6 ± 1.9 vs. 32.8 ± 2.6 cm2; P < 0.001). Entrainment mapping enables an accurate quantification of the effects of gastric pacing on slow-wave activity, offering an improved method to assess whether pacing protocols are likely to achieve physiologically and clinically useful outcomes

    Energy saving policies and low energy residential buildings: a LCA case study to support decision-makers in Piedmont (Italy)

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    Background, aim and scope A low-energy family house recently built in Northern Italy was selected by Regione Piemonte as an outstanding example of resource efficient building. An economic incentive was awarded to cover the extra costs of the thermal insulation, windows and equipment in order to decrease the yearly winter heat requirement from the legal standard of 109 to 10 kW h/m2, while existing buildings in the study area typically require 200 kW h/m2. As the building was claimed to be sustainable on the basis of its outstanding energy-saving performance, an ex post life cycle assessment (LCA) was set up to understand whether, and to what extent, the positive judgement could be confirmed in a life cycle perspective. Materials and methods After an analysis of the literature on LCA of whole buildings, a detailed life cycle assessment has been conducted by encompassing all the life cycle phases. Emphasis was given on the end-of-life stage, too often disregarded due to lack of data or heavily simplified. Virtually all the materials used in the building structure, finishes and equipment were considered, paying attention to their expected service duration and the recycling potential. In order to increase transparency and therefore credibility and acceptance of LCA in the building sector, an uncertainty analysis was carried out. Results and discussion The dramatic contribution of material-related impacts emerged. Structure and finishes materials represented the highest relative contribution, but maintenance operations also played a major role. The contributions of equipment, construction stage and transportation were minor. The important role of the recycling potential also emerged. Unlike standard buildings, where heating-related impacts overshadow the rest of the life cycle, there is no single dominating item or aspect. Rather, several of them play equally important roles. Conclusions The study confirmed that the initial goal of resource and environmental efficiency was reached, but to a much lower extent than previously thought. In comparison to a standard house, while the winter heat requirement was reduced from 109 to 10 kW h/m2 (10:1 ratio), the life cycle energy was only reduced by 2.1:1 and the carbon footprint by 2.2:1. Recommendations and perspectives The findings emphasise the need for incorporating the life cycle approach in energy-saving policies and economic incentives schemes in the building sector, in Italy and elsewhere, as single-step improvements might not be effective in a life cycle perspective and could even disappoint expectation
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