1,248 research outputs found
Co-electrolysis of H2O and CO2 on exsolved Ni nanoparticles for efficient syngas generation at controllable H2/CO ratios
Syngas (CO+H2) is a key-intermediate for the production of liquid fuels via the Fischer-Tropsch process. An emerging technology for generating syngas is the co-electrolysis of H2O/CO2 in solid oxide cells powered by renewable electricity. An application of this technology, however, is still challenging because the Ni-based cermet fuel electrodes are susceptible to degradation under redox and coking conditions, requiring protective hydrogen atmosphere to maintain stable operation. Perovskite oxides are the most promising alternatives due to their redox stability, extensive range of functionalities and the exsolution concept. The latter allows perovskites to be decorated with uniformly dispersed Ni nanoparticles with unique functionalities that can dramatically enhance the performance. Herein, we demonstrate the advantage of employing a nanoparticle-decorated La0.43Ca0.37Ni0.06Ti0.94O3 (LCT-Ni) perovskite to efficiently generate syngas at adjustable H2/CO ratios and simultaneously avoid the need of a reducing agent, hence decreasing the total cost and complexity of the process
Weather shocks and agricultural commercialization in colonial tropical Africa: did cash crops alleviate social distress?
A rapidly growing body of research examines the ways in which climatic variability influence economic and societal outcomes. This study investigates how weather shocks triggered social distress in British colonial Africa. Further, it intervenes in a long-standing and unsettled debate concerning the effects of agricultural commercialization on the abilities of rural communities to cope with exogenous shocks. We collect qualitative evidence from annual administrative records to explore the mechanisms linking weather extremes to harvest failures and social distress. We also conduct econometric testing on a novel panel dataset of 143 administrative districts across west, south-central and east Africa in the Interwar Era (1920-1939). Our findings are twofold. First, we find robust evidence that rainfall anomalies (both drought and excessive precipitation) are associated with spikes in imprisonment (our proxy for social distress). We argue that the key causal pathway is the loss of agricultural income, which results in higher imprisonment for theft, unrest, debt and tax default. Second, we find that the impact of weather shocks on distress is partially mitigated by the cultivation of export crops. Our findings suggest that, even in the British colonial context, smallholder export crop cultivation led to higher private incomes as well as greater public investment. Our findings speak to a topic of considerable urgency today as the process of global climate change accelerates, generating more severe and unpredictable climatic extremes. An increased understanding and identification of adaptive and mitigating factors, would assist in targeting policy interventions and designing adaptive institutions to support vulnerable rural societies
Appropriate Osteoporosis Treatment by Family Physicians inResponse to FRAX vs CAROC Reporting: Results Froma Randomized Controlled Trial
© 2014 The International Society for Clinical Densitometry. Canadian guidelines recommend either the FRAX or the Canadian Association of Radiologists and Osteoporosis Canada (CAROC) fracture risk assessment tools to report 10-yr fracture risk as low (20%). It is unknown whether one reporting system is more effective in helping family physicians (FPs) identify individuals who require treatment. Individuals ≥50yr old with a distal radius fracture and no previous osteoporosis diagnosis or treatment were recruited. Participants underwent a dual-energy x-ray absorptiometry scan and answered questions about fracture risk factors. Participants\u27 FPs were randomized to receive either a FRAX report or the standard CAROC-derived bone mineral density report currently used by the institution. Only the FRAX report included statements regarding treatment recommendations. Within 3 mo, all participants were asked about follow-up care by their FP, and treatment recommendations were compared with anosteoporosis specialist. Sixty participants were enrolled (31 to FRAX and 29 to CAROC). Kappa statistics of agreement in treatment recommendation were 0.64 for FRAX and 0.32 for bone mineral density. The FRAX report was preferred by FPs and resulted in better postfracture follow-up and treatment that agreed more closely with a specialist. Either the clear statement of fracture risk or the specific statement of treatment recommendations on the FRAX report may have supported FPs to make better treatment decisions
Geometric morphometrics aided by machine learning in craniofacial surgery
Geometric morphometrics aided by machine learning provide detailed and accurate statistical models of facial form. They promise to be extremely effective tools in surgical planning and assessment; however, a clinical tool to use this information is still to be created
Achievement goals and motivational responses in tennis: Does the context matter?
Objectives: This study examined: (a) whether athletes’ goal orientations differ across training and competition; (b) whether goal orientations predict effort, enjoyment, and psychological skill use differently in training and competition; and (c) whether goal orientations predict perceived improvement in training and perceived performance in competition.
Method: Participants were 116 competitive tennis players (mean age = 19.99, SD = 5.82), who completed questionnaires measuring goal orientations, effort, enjoyment, and psychological skill use in training and competition, perceived improvement in training, and perceived performance in competition.
Results: Dependent t-tests revealed that athletes reported higher task orientation in training than in competition and higher ego orientation in competition than in training, while Pearson product-moment correlations revealed a high cross-contextual consistency for both task and ego goal orientations between training and competition. Regression analyses indicated that task orientation predicted positively effort, enjoyment, self-talk, and goal setting in both contexts, perceived improvement in training, and perceived performance in competition. An interaction effect also emerged whereby ego orientation predicted positively effort in competition only when task orientation was low or average.
Conclusions: The findings suggest that goal orientations may differ between training and competition; task orientation is the goal that should be promoted in both contexts; and the context may affect the relationship between goal orientations and effort, enjoyment, and goal setting
Local Soft Tissue and Bone Displacements Following Midfacial Bipartition Distraction in Apert Syndrome – Quantification Using a Semi-Automated Method
ABSTRACT: Patients with Apert syndrome experience midfacial hypoplasia, hypertelorism, and downslanting palpebral fissures which can be corrected by midfacial bipartition distraction with rigid external distraction device. Quantitative studies typically focus on quantifying rigid advancement and rotation postdistraction, but intrinsic shape changes of bone and soft tissue remain unknown. This study presents a method to quantify these changes. Pre- and post-operative computed tomography scans from patients with Apert syndrome undergoing midfacial bipartition distraction with rigid external distraction device were collected. Digital Imaging and Communications in Medicine files were converted to three-dimensional bone and soft tissue reconstructions. Postoperative reconstructions were aligned on the preoperative maxilla, followed by nonrigid iterative closest point transformation to determine local shape changes. Anatomical point-to-point displacements were calculated and visualized using a heatmap and arrow map. Nine patients were included.Zygomatic arches and frontal bone demonstrated the largest changes. Mid-lateral to supra-orbital rim showed an upward, inward motion. Mean bone displacements ranged from 3.3 to 12.8 mm. Soft tissue displacements were relatively smaller, with greatest changes at the lateral canthi. Midfacial bipartition distraction with rigid external distraction device results in upward, inward rotation of the orbits, upward rotation of the zygomatic arch, and relative posterior motion of the frontal bone. Local movements were successfully quantified using a novel method, which can be applied to other surgical techniques/syndromes
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