61 research outputs found

    Non-contact boundary layer profiler using low-coherence self-referencing velocimetry

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    A spatially self-referencing velocimetry system based on low-coherence interferometry has been developed. The measurement technique is contactless and relies on the interference between back-reflected light from an arbitrary reference surface and seeding particles in the flow. The measurement location and the flow velocity are measured relative to the reference surface's location and velocity, respectively. Scanning of the measurement location along the beam direction does not require mechanical movement of the sensor head. The reference surface (which can move or vibrate relative to the sensor head) can be either an external object or the surface of a body over which measurements are to be performed. The absolute spatial accuracy and the spatial resolution only depend on the coherence length of the light source (tens of microns for a superluminescent diode). The prototype is an all-fiber assembly. An optical fiber of arbitrary length connects the self-contained optical and electronics setup to the sensor head. Proof-of-principle measurements in water (Taylor-Couette flow) and in air (Blasius boundary layer) are reported in this pape

    Riverine transfer of heavy metals from Patagonia to the southwestern Atlantic Ocean

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    The occurrence and geochemical behaviour of Fe, Mn, Pb, Cu, Ni, Cr, Zn and Co are studied in riverine detrital materials transported by Patagonian rivers. Their riverine inputs have been estimated and the nature of these inputs to the Atlantic Ocean is discussed. Most of the metals are transported to the ocean via the suspended load; there is evidence that Fe oxides and organic matter are important phases controlling their distribution in the detrital non-residual fraction. Most heavy metal concentrations found in bed sediments, in suspended matter, and in the dissolved load of Patagonian rivers were comparable to those reported for non-polluted rivers. There is indication that human activity is altering riverine metal inputs to the ocean. In the northern basins – and indicatinganthropogenic effects – heavy metals distribution in the suspended load is very different from that found in bed sediments. The use of pesticides in the Negro River valley seems correlated with increased riverine input of Cu, mostly bound to the suspended load. The Deseado and Chico Rivers exhibit increased specific yield of metals as a consequence of extended erosion within their respective basins. The Santa Cruz is the drainage basin least affected by human activity and its metal-exporting capacity should be taken as an example of a relatively unaffected large hydrological system. In contrast, coal mining modifies the transport pattern of heavy metals in the Gallegos River, inasmuch as they are exported to the coastal zone mainly as dissolved load

    The “hockey” assist makes the difference:validation of a defensive disruptiveness model to evaluate passing sequences in elite soccer

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    With the growing availability of position data in sports, spatiotemporal analysis in soccer is a topic of rising interest. The aim of this study is to validate a performance indicator, namely D-Def, measuring passing effectiveness. D-Def calculates the change of the teams’ centroid, centroids of formation lines (e.g., defensive line), teams’ surface area, and teams’ spread in the following three seconds after a pass and therefore results in a measure of disruption of the opponents’ defense following a pass. While this measure was introduced earlier, in this study we aim to prove the usefulness to evaluate attacking sequences. In this study, 258 games of Dutch Eredivisie season 2018/19 were included, resulting in 13,094 attacks. D-Def, pass length, pass velocity, and pass angle of the last four passes of each attack were calculated and compared between successful and unsuccessful attacks. D-Def showed higher values for passes of successful compared to unsuccessful attacks (0.001 28) needs to be present. In addition, the penultimate pass (“hockey assist”) of an attack seems crucial in characterizing successful attacks

    The “hockey” assist makes the difference—validation of a defensive disruptiveness model to evaluate passing sequences in elite soccer

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    With the growing availability of position data in sports, spatiotemporal analysis in soccer is a topic of rising interest. The aim of this study is to validate a performance indicator, namely D-Def, measuring passing effectiveness. D-Def calculates the change of the teams’ centroid, centroids of formation lines (e.g., defensive line), teams’ surface area, and teams’ spread in the following three seconds after a pass and therefore results in a measure of disruption of the opponents’ defense following a pass. While this measure was introduced earlier, in this study we aim to prove the usefulness to evaluate attacking sequences. In this study, 258 games of Dutch Eredivisie season 2018/19 were included, resulting in 13,094 attacks. D-Def, pass length, pass velocity, and pass angle of the last four passes of each attack were calculated and compared between successful and unsuccessful attacks. D-Def showed higher values for passes of successful compared to unsuccessful attacks (0.001 28) needs to be present. In addition, the penultimate pass (“hockey assist”) of an attack seems crucial in characterizing successful attacks

    Predicting the oceanic input of organic carbon by continental erosion

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    For a large set of major world rivers we established the empirical relations existing betwin the observed organic carbon fluxes and the climatic, biologic, and geomorphologic paterns characterizing the river basins.These characteristics where extracting from various ecological databases. The corresponding carbon fluxes were taken from the literature. Dissolved organic carbon fluxes are mainly related to drainage intensity, basin slope, and the amount of carbon stored in soils. Particulate organic carbon fluxes are calculated as a function of sediment fluxes, which depend principally upon drainage intensy, rainfall intensity, and basin slope. Although the drainage intensity is mainly related to the amount of precipitation and to mean temperature in the basin, slope is also retained as one of controlling factors. Our empirical models result in a total organic carbon flux to the oceans of about 0.38 Gt per year globally. About 0.21 Gt carbon (Gt C)enter the oceans in dissolved from and about 0.17 Gt C in particulate form. we further regionalize fluxes with respect to major climates, different continents, and different ocean basins. About 45% of the organic carbon is discharged from tropical wet regions. the major part of the dissolved organic carbon is discharged into the Atlantic Ocean, while the bulk of the particulate organic carbon is discharged into the Indian and Pacific Oceans

    The Controlled Synthesis of Carbon Tubes and Rods by Template-Assisted Twin Polymerization

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    The application of porous carbon is versatile. It is used for high-performance catalyst support, electrode material in batteries, and gas storage. In each of these application fields nanostructuring improves the material properties. Supercapacitors store a high energy density. Exactly adapted carbon structures increase the life of lithium batteries and protect catalysts with increasing reaction rate and selectivity. Most of porous carbon materials have a spherical shape. To the best of our knowledge, there is no procedure to synthesize nanostructured cylindrical porous carbon systematically. Here, template glass fibres and SiO2-tubes were modified with nanostructured SiO2/phenolic resin and SiO2/poly(furfuryl alcohol) layers by surface twin polymerization (TP) of 2,2′-spirobi[4H-1,3,2-benzodioxasiline] and tetrafurfuryloxysilane. Afterwards the SiO2/polymer layer on the template is thermally transformed into a defect-free nanostructured SiO2/carbon layer. After completely removing the SiO2 components microporous carbon tubes or rods are finally achieved. The diameters of the carbon rods and the inner as well as the outer diameter of the carbon tubes are adjustable according to the shape and size of the template. Thus, a huge variety of microporous carbon materials can be easily produced by template-assisted TP

    Albiglutide and cardiovascular outcomes in patients with type 2 diabetes and cardiovascular disease (Harmony Outcomes): a double-blind, randomised placebo-controlled trial

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    Background: Glucagon-like peptide 1 receptor agonists differ in chemical structure, duration of action, and in their effects on clinical outcomes. The cardiovascular effects of once-weekly albiglutide in type 2 diabetes are unknown. We aimed to determine the safety and efficacy of albiglutide in preventing cardiovascular death, myocardial infarction, or stroke. Methods: We did a double-blind, randomised, placebo-controlled trial in 610 sites across 28 countries. We randomly assigned patients aged 40 years and older with type 2 diabetes and cardiovascular disease (at a 1:1 ratio) to groups that either received a subcutaneous injection of albiglutide (30–50 mg, based on glycaemic response and tolerability) or of a matched volume of placebo once a week, in addition to their standard care. Investigators used an interactive voice or web response system to obtain treatment assignment, and patients and all study investigators were masked to their treatment allocation. We hypothesised that albiglutide would be non-inferior to placebo for the primary outcome of the first occurrence of cardiovascular death, myocardial infarction, or stroke, which was assessed in the intention-to-treat population. If non-inferiority was confirmed by an upper limit of the 95% CI for a hazard ratio of less than 1·30, closed testing for superiority was prespecified. This study is registered with ClinicalTrials.gov, number NCT02465515. Findings: Patients were screened between July 1, 2015, and Nov 24, 2016. 10 793 patients were screened and 9463 participants were enrolled and randomly assigned to groups: 4731 patients were assigned to receive albiglutide and 4732 patients to receive placebo. On Nov 8, 2017, it was determined that 611 primary endpoints and a median follow-up of at least 1·5 years had accrued, and participants returned for a final visit and discontinuation from study treatment; the last patient visit was on March 12, 2018. These 9463 patients, the intention-to-treat population, were evaluated for a median duration of 1·6 years and were assessed for the primary outcome. The primary composite outcome occurred in 338 (7%) of 4731 patients at an incidence rate of 4·6 events per 100 person-years in the albiglutide group and in 428 (9%) of 4732 patients at an incidence rate of 5·9 events per 100 person-years in the placebo group (hazard ratio 0·78, 95% CI 0·68–0·90), which indicated that albiglutide was superior to placebo (p<0·0001 for non-inferiority; p=0·0006 for superiority). The incidence of acute pancreatitis (ten patients in the albiglutide group and seven patients in the placebo group), pancreatic cancer (six patients in the albiglutide group and five patients in the placebo group), medullary thyroid carcinoma (zero patients in both groups), and other serious adverse events did not differ between the two groups. There were three (<1%) deaths in the placebo group that were assessed by investigators, who were masked to study drug assignment, to be treatment-related and two (<1%) deaths in the albiglutide group. Interpretation: In patients with type 2 diabetes and cardiovascular disease, albiglutide was superior to placebo with respect to major adverse cardiovascular events. Evidence-based glucagon-like peptide 1 receptor agonists should therefore be considered as part of a comprehensive strategy to reduce the risk of cardiovascular events in patients with type 2 diabetes. Funding: GlaxoSmithKline

    Large expert-curated database for benchmarking document similarity detection in biomedical literature search

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    Document recommendation systems for locating relevant literature have mostly relied on methods developed a decade ago. This is largely due to the lack of a large offline gold-standard benchmark of relevant documents that cover a variety of research fields such that newly developed literature search techniques can be compared, improved and translated into practice. To overcome this bottleneck, we have established the RElevant LIterature SearcH consortium consisting of more than 1500 scientists from 84 countries, who have collectively annotated the relevance of over 180 000 PubMed-listed articles with regard to their respective seed (input) article/s. The majority of annotations were contributed by highly experienced, original authors of the seed articles. The collected data cover 76% of all unique PubMed Medical Subject Headings descriptors. No systematic biases were observed across different experience levels, research fields or time spent on annotations. More importantly, annotations of the same document pairs contributed by different scientists were highly concordant. We further show that the three representative baseline methods used to generate recommended articles for evaluation (Okapi Best Matching 25, Term Frequency-Inverse Document Frequency and PubMed Related Articles) had similar overall performances. Additionally, we found that these methods each tend to produce distinct collections of recommended articles, suggesting that a hybrid method may be required to completely capture all relevant articles. The established database server located at https://relishdb.ict.griffith.edu.au is freely available for the downloading of annotation data and the blind testing of new methods. We expect that this benchmark will be useful for stimulating the development of new powerful techniques for title and title/abstract-based search engines for relevant articles in biomedical research.Peer reviewe

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    The Success Factors of Rest Defense in Soccer:A Mixed-Methods Approach of Expert Interviews, Tracking Data, and Machine Learning

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    While the tactical behavior of soccer players differs between specific phases of play (offense, defense, offensive transition, defensive transition), little is known about successful behavior of players during defensive transition (switching behavior from offense to defense). Therefore, this study aims to analyze the group tactic of rest defense (despite in ball possession, certain players safeguard quick counterattacks in case of ball loss) in defensive transition. A mixed-methods approach was used, involving both qualitative and quantitative analysis. Semi-structured expert interviews with seven professional soccer coaches were conducted to define rest defense. In the quantitative analysis, several KPIs were calculated, based on tracking and event data of 153 games of the 2020/21 German Bundesliga season, to predict the success of rest defense situations in a machine learning approach. The qualitative interviews indicated that rest defense can be defined as the positioning of the deepest defenders during ball possession to prevent an opposing counterattack after a ball loss. For instance, the rest defending players created a numerical superiority of 1.69 ± 1.00 and allowed a space control of the attacking team of 11.51 ± 9.82 [%] in the area of rest defense. The final machine learning model showed satisfactory prediction performance of the success of rest defense (Accuracy: 0.97, Precision: 0.73, f1-Score: 0.64, AUC: 0.60). Analysis of the individual KPIs revealed insights into successful behavior of players in rest defense, including controlling deep spaces and dangerous counterattackers. The study concludes regaining possession as fast as possible after a ball loss is the most important success factor in defensive transition.</p
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