935 resultados para point-to-segment algorithm


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Re-imagining of the aerial transportation system has become increasingly important as the need for significant environmental and economic efficiency gains has become ever more prevalent. A number of studies have highlighted the benefits of the adoption of air to air refuelling within civil aviation. However, it also opens up the potential for increased flexibility in operations through smaller aircraft, shifting emphasis away from the traditional hub and spoke method of operation towards the more flexible Point to Point operations. It is proposed here that one technology can act as an enabler for the other, realising benefits that neither can realise as a standalone. The impact of an air-toair refuelling enabled point to point system is discussed, and the affect on economic and environmental cost metrics relative to traditional operations evaluated. An idealised airport configuration study shows the difference in fuel burn for point to point networks to vary from -23% to 28% from that of Hub and Spoke depending on the configuration. The sensitive natures of the concepts are further explored in a second study based on real airport configurations. The complex effect of the choice of a Point to Point or Hub and Spoke system on fuel burn, operating cost and revenue potential is highlighted. Fuel burn savings of 15% can be experienced with AAR over traditional refuelling operations, with point to point networks increasing the available seat miles (by approximately 20%) without a proportional increase in operating cost or fuel.

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The description of the image reads "Magnificent outlook over Niagara, world's grandest waterfall, from Prospect Point to Horseshoe Falls". The side of the card is also stamped "By Royal Command to Their Imperial Majesties King George V and Queen Mary".

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This 5-minute video describes how you can assess how confident your students were with their answer choices so you can adapt your teaching appropriately.

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This short video shows how you can save the date at the end of a Turning Point quiz, then view that data as an Excel spreadsheet.

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The search for ever deeper relationships among the World’s languages is bedeviled by the fact that most words evolve too rapidly to preserve evidence of their ancestry beyond 5,000 to 9,000 y. On the other hand, quantitative modeling indicates that some “ultraconserved” words exist that might be used to find evidence for deep linguistic relationships beyond that time barrier. Here we use a statistical model, which takes into account the frequency with which words are used in common everyday speech, to predict the existence of a set of such highly conserved words among seven language families of Eurasia postulated to form a linguistic superfamily that evolved from a common ancestor around 15,000 y ago. We derive a dated phylogenetic tree of this proposed superfamily with a time-depth of ∼14,450 y, implying that some frequently used words have been retained in related forms since the end of the last ice age. Words used more than once per 1,000 in everyday speech were 7- to 10-times more likely to show deep ancestry on this tree. Our results suggest a remarkable fidelity in the transmission of some words and give theoretical justification to the search for features of language that might be preserved across wide spans of time and geography.

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Plant extracts are some of the most attractive sources of new drugs and have shown promising results for the treatment of gastric ulcers. Several folk medicinal plants and herbs have been used to treat gastrointestinal disorders, including gastric ulcers. Mammea americana L. (Guttiferae) fruit is very common in the diet of the population of northern South America. Our research interest in this plant arose because of its potential medicinal value as a tonic and against stomachache, as used in folk medicine. In this paper we evaluated three different extracts (ethanolic/EtOH, methanolic/MeOH and dichloromethane/DCM) obtained from M. americana L., for their ability to protect the gastric mucosa against injuries caused by necrotizing agents (0.3 M HCI/60% EtOH), hypothermic restraint stress, nonsteroidal anti-inflammatory drugs (NSAID, indomethacin) and pylorus ligation. In the HCI/EtOH-induced gastriculcer model, EtOH and DCM extracts demonstrated significant inhibition of the ulcerative lesion index by 54% (12.0 +/- 2.6 mm) and 86% (3.7 +/- 1.8 mm), respectively, in relation to the control value (26.0 +/- 1.4 mm) (p < 0.000 1). In the NSAID/cholinomimetic-induced lesion model, both EtOH and DCM extracts showed antiulcerogenic effects with significant reduction in the damage to these gastric lesions of 36% (8.3 +/- 2.0 mm) and 42% (7.5 +/- 1.4 mm), respectively, as compared to the control group (13.0 +/- 0.9 mm) (p < 0.0001). In the gastric ulcer induced by hypothermic-restraint stress, both extracts also showed significant activity, and inhibited the gastric lesion index by 58% and 75%, respectively. The EtOH and DCM extracts also changed gastric juice parameters as well as those of cimetidine, decreased gastric acid secretion significantly (p < 0.0001), increased pH values and promoted reduced acid output (p < 0.0001). In all gastric-ulcer-induced models, MeOH extract did not show any significant antiulcerogenic activity, nor did it change gastric-juice parameters (p > 0.05). The results suggest that EtOH and DCM extracts obtained from M. americana possess excellent antisecretory and/or gastrotective effect in all gastric ulcer models. These results suggest that the antiulcerogenic compound(s) present in M. americana may be clustered in the apolar fraction, which will be investigated by our group for the probable mechanisms of action. (c) 2004 Elsevier GmbH. All rights reserved.

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BACKGROUND & AIMS: Recently, genetic variations in MICA (lead single nucleotide polymorphism [SNP] rs2596542) were identified by a genome-wide association study (GWAS) to be associated with hepatitis C virus (HCV)-related hepatocellular carcinoma (HCC) in Japanese patients. In the present study, we sought to determine whether this SNP is predictive of HCC development in the Caucasian population as well. METHODS: An extended region around rs2596542 was genotyped in 1924 HCV-infected patients from the Swiss Hepatitis C Cohort Study (SCCS). Pair-wise correlation between key SNPs was calculated both in the Japanese and European populations (HapMap3: CEU and JPT). RESULTS: To our surprise, the minor allele A of rs2596542 in proximity of MICA appeared to have a protective impact on HCC development in Caucasians, which represents an inverse association as compared to the one observed in the Japanese population. Detailed fine-mapping analyses revealed a new SNP in HCP5 (rs2244546) upstream of MICA as strong predictor of HCV-related HCC in the SCCS (univariable p=0.027; multivariable p=0.0002, odds ratio=3.96, 95% confidence interval=1.90-8.27). This newly identified SNP had a similarly directed effect on HCC in both Caucasian and Japanese populations, suggesting that rs2244546 may better tag a putative true variant than the originally identified SNPs. CONCLUSIONS: Our data confirms the MICA/HCP5 region as susceptibility locus for HCV-related HCC and identifies rs2244546 in HCP5 as a novel tagging SNP. In addition, our data exemplify the need for conducting meta-analyses of cohorts of different ethnicities in order to fine map GWAS signals.

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BACKGROUND Early identification of patients at risk of developing persistent low back pain (LBP) is crucial. OBJECTIVE Aim of this study was to identify in patients with a new episode of LBP the time point at which those at risk of developing persistent LBP can be best identified.METHODS: Prospective cohort study of 315 patients presenting to a health practitioner with a first episode of acute LBP. Primary outcome measure was functional limitation. Patients were assessed at baseline, three, six, twelve weeks and six months looking at factors of maladaptive cognition as potential predictors. Multivariate logistic regression analysis was performed for all time points. RESULTS The best time point to predict the development of persistent LBP at six months was the twelve-week follow-up (sensitivity 78%; overall predictive value 90%). Cognitions assessed at first visit to a health practitioner were not predictive. CONCLUSIONS Maladaptive cognitions at twelve weeks appear to be suitable predictors for a transition from acute to persistent LBP. Already three weeks after patients present to a health practitioner with acute LBP cognitions might influence the development of persistent LBP. Therefore, cognitive-behavioral interventions should be considered as early adjuvant LBP treatment in patients at risk of developing persistent LBP.