969 research outputs found

    Summary of International Transport Energy Modeling Workshop

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    The NextSTEPS program at ITS-Davis convened a one-day workshop on international transportation energy modeling (iTEM), focused on comparing the frameworks and scenario projections from four major global transport models: -- Global Change Assessment Model (GCAM) by Pacific Northwest National Laboratory (PNNL) and ITS-Davis, -- MESSAGE-Transport (Model for Energy Supply Strategy Alternatives and their General Environmental Impact) by the International Institute for Applied Systems Analysis (IIASA), -- Mobility Model (MoMo) by the International Energy Agency, and -- Roadmap by the International Council on Clean Transportation (ICCT). Highlights: -- Projections of "baseline" global transportation energy use rise from 98 EJ in 2010 to 160-250 EJ by 2050. -- There are considerable differences in historical data for some modes, both globally and for individual countries (particularly non-OECD countries). Variability in estimates of transportation activity are in most cases much larger than energy differences. -- Global average vehicle ownership rates are projected to range from 270 to 450 per 1,000 people by 2050 with wide ranges across countries: 700-1,075 for the US by the middle of the century (US is around 700 today), 100-650 for China, and 80-380 for India across four models. -- All models rely mainly on GDP to estimate the future demand for freight and hold the base year modal shares (e.g. truck v. rail) roughly constant through 2050. In reality, future evolution will depend on characteristics of products (e.g. type of commodities) being shipped, technologies available for freight and their efficiencies, and policies and infrastructure. -- Current policy commitments toward EVs, PHEVs and H2FCVs (and thus baseline projections) maybe below the numbers suggested by iTEM models as required for meeting climate targets (e.g., 2 degrees C). -- Improvements in data quality and the representation of car ownership and use across the models were identified as priorities. Modeling transport energy use can either be done by estimating how far people travel and what mode of transportation they choose or by estimating how many vehicles there are and how far each one travels. These are complementary approaches, and in theory they should both lead to the same answer. The former approach, used in "service demand" models, seem more intuitive when one wants to model societal shifts in modes of transportation, either in emerging economies as they develop or in developed economies as they decarbonize; but collecting data on service demand is notoriously difficult. In contrast, vehicle stock models use readily-available vehicle sales data, but are harder to use in future-state, what-if scenarios (particularly in estimating modal shift behaviors) and thus require special attention by experts. The four iTEM models are different in terms of scope (GCAM and MESSAGE cover all sectors of the energy system vs. MoMo and Roadmap which cover transportation only) and model structure (GCAM and MESSAGE rely on internal drivers, particularly the costs of technology and travel, to project future changes whereas MoMo and Roadmap rely on experts' judgments and detailed analysis of technology and policies to drive long-term changes). Yet, owing to these differences, the models are highly complementary and in some cases can be used jointly to answer questions that no single model can tackle on its own. The following summary shares some of the comparisons and findings from the workshop

    Expedition Earth and Beyond: Engaging Classrooms in Student-Led Research Using NASA Data, Access to Scientists, and Integrated Educational Strategies

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    Classroom teachers are challenged with engaging and preparing today s students for the future. Activities are driven by state required skills, education standards, and high-stakes testing. Providing educators with standards-aligned, inquiry-based activities that will help them engage their students in student-led research in the classroom will help them teach required standards, essential skills, and help inspire their students to become motivated learners. The Astromaterials Research and Exploration Science (ARES) Education Program, classroom educators, and ARES scientists at the NASA Johnson Space Center created the Expedition Earth and Beyond education program to help teachers promote student-led research in their classrooms (grades 5-14) by using NASA data, providing access to scientists, and using integrated educational strategies

    Mapping interactions between the sustainable development goals: lessons learned and ways forward

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    Pursuing integrated research and decision-making to advance action on the sustainable development goals (SDGs) fundamentally depends on understanding interactions between the SDGs, both negative ones (“trade-offs”) and positive ones (“co-benefits”). This quest, triggered by the 2030 Agenda, has however pointed to a gap in current research and policy analysis regarding how to think systematically about interactions across the SDGs. This paper synthesizes experiences and insights from the application of a new conceptual framework for mapping and assessing SDG interactions using a defined typology and characterization approach. Drawing on results from a major international research study applied to the SDGs on health, energy and the ocean, it analyses how interactions depend on key factors such as geographical context, resource endowments, time horizon and governance. The paper discusses the future potential, barriers and opportunities for applying the approach in scientific research, in policy making and in bridging the two through a global SDG Interactions Knowledge Platform as a key mechanism for assembling, systematizing and aggregating knowledge on interactions

    Vascular complications of prosthetic inter-vertebral discs

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    Five consecutive cases of prosthetic inter-vertebral disc displacement with severe vascular complications on revisional surgery are described. The objective of this case report is to warn spinal surgeons that major vascular complications are likely with anterior displacement of inter-vertebral discs. We have not been able to find a previous report on vascular complications associated with anterior displacement of prosthetic inter-vertebral discs. In all five patients the prosthetic disc had eroded into the bifurcation of the inferior vena cava and the left common iliac vein. In three cases the aortic bifurcation was also involved. The fibrosis was so severe that dissecting out the arteries and veins to provide access to the relevant disc proved impossible. Formal division of the left common iliac vein and artery with subsequent repair was our solution. Anterior inter-vertebral disc displacement was associated with severe vascular injury. Preventing anterior disc displacement is essential in disc design. In the event of anterior displacement, disc removal should be planned with a Vascular Surgeon

    Renormalization Group Analysis of a Quivering String Model of Posture Control

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    Scaling concepts and renormalization group (RG) methods are applied to a simple linear model of human posture control consisting of a trembling or quivering string subject to damping and restoring forces. The string is driven by uncorrelated white Gaussian noise intended to model the corrections of the physiological control system. We find that adding a weak quadratic nonlinearity to the posture control model opens up a rich and complicated phase space (representing the dynamics) with various non-trivial fixed points and basins of attraction. The transition from diffusive to saturated regimes of the linear model is understood as a crossover phenomenon, and the robustness of the linear model with respect to weak non-linearities is confirmed. Correlations in posture fluctuations are obtained in both the time and space domain. There is an attractive fixed point identified with falling. The scaling of the correlations in the front-back displacement, which can be measured in the laboratory, is predicted for both the large-separation (along the string) and long-time regimes of posture control.Comment: 20 pages, 13 figures, RevTeX, accepted for publication in PR

    Randomized clinical trial of percutaneous transluminalangioplasty, supervised exercise and combined treatment forintermittent claudication due to femoropopliteal arterial disease

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    Background:The aim was to compare percutaneous transluminal angioplasty (PTA), a supervisedexercise programme (SEP) and combined treatment (PTA plus SEP) for intermittent claudication dueto femoropopliteal arterial disease.Methods: Consenting patients with femoropopliteal arterial lesions were randomized to one of threetreatment arms: PTA, SEP, or PTA plus SEP. All patients received optimal medical treatment. Patientswere assessed at baseline and 1, 3, 6 and 12 months after intervention. Clinical (ankle pressures, walkingdistances, symptoms) and quality-of-life (QoL) outcomes (Short Form 36, VascuQol) were analysed.Results: A total of 178 patients (108 men, median age 70 years) were included. All three treatmentgroups demonstrated significant clinical and QoL improvements. One year after PTA (60 patients, 8withdrew), 37 patients (71 per cent) had improved (16 mild, 16 moderate, 5 marked), nine (17 per cent)showed no improvement and six (12 per cent) had deteriorated. After SEP (60 patients, 14 withdrew),32 patients (70 per cent) had improved (19 mild, 10 moderate, 3 marked), six (13 per cent) showed noimprovement and eight (17 per cent) had deteriorated. After PTA plus SEP (58 patients, 11 withdrew),40 patients (85 per cent) had improved (18 mild, 20 moderate, 2 marked), seven (15 per cent) showedno improvement and none had deteriorated. On intergroup analysis, PTA and SEP alone were equallyeffective in improving clinical outcomes, although the effect was short-lived. PTA plus SEP produced amore sustained clinical improvement, but there was no significant QoL advantage.Conclusion: For patients with intermittent claudication due to femoropopliteal disease, PTA, SEP,and PTA plus SEP were all equally effective in improving walking distance and QoL after 12 months.Registration number: NCT00798850 (http://www.clinicaltrials.gov)

    Length of carotid stenosis predicts peri-procedural stroke or death and restenosis in patients randomized to endovascular treatment or endarterectomy.

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    BACKGROUND: The anatomy of carotid stenosis may influence the outcome of endovascular treatment or carotid endarterectomy. Whether anatomy favors one treatment over the other in terms of safety or efficacy has not been investigated in randomized trials. METHODS: In 414 patients with mostly symptomatic carotid stenosis randomized to endovascular treatment (angioplasty or stenting; n = 213) or carotid endarterectomy (n = 211) in the Carotid and Vertebral Artery Transluminal Angioplasty Study (CAVATAS), the degree and length of stenosis and plaque surface irregularity were assessed on baseline intraarterial angiography. Outcome measures were stroke or death occurring between randomization and 30 days after treatment, and ipsilateral stroke and restenosis ≥50% during follow-up. RESULTS: Carotid stenosis longer than 0.65 times the common carotid artery diameter was associated with increased risk of peri-procedural stroke or death after both endovascular treatment [odds ratio 2.79 (1.17-6.65), P = 0.02] and carotid endarterectomy [2.43 (1.03-5.73), P = 0.04], and with increased long-term risk of restenosis in endovascular treatment [hazard ratio 1.68 (1.12-2.53), P = 0.01]. The excess in restenosis after endovascular treatment compared with carotid endarterectomy was significantly greater in patients with long stenosis than with short stenosis at baseline (interaction P = 0.003). Results remained significant after multivariate adjustment. No associations were found for degree of stenosis and plaque surface. CONCLUSIONS: Increasing stenosis length is an independent risk factor for peri-procedural stroke or death in endovascular treatment and carotid endarterectomy, without favoring one treatment over the other. However, the excess restenosis rate after endovascular treatment compared with carotid endarterectomy increases with longer stenosis at baseline. Stenosis length merits further investigation in carotid revascularisation trials

    Migrant workers' engagement with labour market intermediaries in Europe: symbolic power guiding transnational exchange

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    This article explores the strategies of migrant workers from post-socialist Central and Eastern Europe (CEE) within the process of transnational exchange characterized by transnational labour market intermediaries that have substantially altered the former national bilateral employment relations. Utilizing a Bourdieuian conceptual framework it examines Slovenian and Polish workers’ migration strategies and struggles to acquire and convert capitals within the process of transnational exchange and upon arrival in the UK. The article uncovers the (self-)colonial cultural capital embodied in CEE workers’ habitus that drives their strategies to take up various working and training opportunities in the UK in order to acquire (trans)nationally recognized cultural capital. This labour of acquisition drives Polish and Slovenian workers to seek specific cross-cultural and ethnic-niche intermediary services that can manipulate the most reliable symbolic signs in order to make profits from migrant worker-consumers. In this regard the article also exposes inter- and intra-ethnic variations

    The burden and risks of pediatric pneumonia in Nigeria: A desk‐based review of existing literature and data

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    Background: Pneumonia is a leading killer of children under‐5 years, with a high burden in Nigeria. We aimed to quantify the regional burden and risks of pediatric pneumonia in Nigeria, and specifically the states of Lagos and Jigawa. / Methods: We conducted a scoping literature search for studies of pneumonia morbidity and mortality in under‐5 children in Nigeria from 10th December 2018 to 26th April 2019, searching: Cochrane, PubMed, and Web of Science. We included grey literature from stakeholders' websites and information shared by organizations working in Nigeria. We conducted multivariable logistic regression using the 2016 to 2017 Multiple Cluster Indicators Survey data set to explore factors associated with pneumonia. Descriptive analyses of datasets from 2010 to 2019 was done to estimate trends in mortality, morbidity, and vaccination coverage. / Results: We identified 25 relevant papers (10 from Jigawa, 8 from Lagos, and 14 national data). None included data on pneumonia or acute respiratory tract infection burden in the health system, inpatient case‐fatality rates, severity, or age‐specific pneumonia mortality rates at state level. Secondary data analysis found that no household or caregiver socioeconomic indicators were consistently associated with self‐reported symptoms of cough and/or difficulty breathing, and seasonality was inconsistently associated, dependant on region. / Conclusion: There is a clear evidence gap around the burden of pediatric pneumonia in Nigeria, and challenges with the interpretation of existing household survey data. Improved survey approaches are needed to understand the risks of pediatric pneumonia in Nigeria, alongside the need for investment in reliable routine data systems to provide data on the clinical pneumonia burden in Nigeria
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