bluuebunny/crossref_metadata_2025_split huggingface dataset:
Market stewardship of quasi‐markets by street level bureaucrats: The role of local area coordinators in the Australian personalisation system
Authors: Malbon Eleanor , Carey Gemma 
Published: May 2020

AbstractWith the rise in popularity of market‐based responses to social policy challenges, the stewardship of quasi‐markets or public service markets, is a key concern for governments worldwide. Debates about how to manage quasi‐markets have focussed on high‐level decision‐making processes. However local actors, in particular street level bureaucrats, are a key part of the complex work of managing quasi‐markets. We examine how street level bureaucrats act as local market stewards in a new quasi‐market for disability care, the Australian National Disability Insurance scheme. We find that the street level bureaucrats, known as local area coordinators, act as shapers of local markets but that their contributions are informal and often restricted by formal structures and processes. For example, we found evidence that the use of key performance indicators can disrupt effective local stewardship efforts towards a procedural approach. We conclude that introducing principles of the polycentric governance approach can improve connections between local market knowledge holders and central decision‐making agencies, thereby improving market stewardship and outcomes.
Hodgkin–Huxley–Katz Prize Lecture: Genetic and pharmacological control of glutamate receptor channel through a highly conserved gating motif
Authors: Perszyk Riley E. , Myers Scott J. , Yuan Hongjie , Gibb Alasdair J. , Furukawa Hiro , Sobolevsky Alexander I. , Traynelis Stephen F. 
Published: May 2020

AbstractGlutamate receptors are essential ligand‐gated ion channels in the central nervous system that mediate excitatory synaptic transmission in response to the release of glutamate from presynaptic terminals. The structural and biophysical basis underlying the function of these receptors has been studied for decades by a wide range of approaches. However recent structural, pharmacological and genetic studies have provided new insight into the regions of this protein that are critical determinants of receptor function. Lack of variation in specific areas of the protein amino acid sequences in the human population has defined three regions in each receptor subunit that are under selective pressure, which has focused research efforts and driven new hypotheses. In addition, these three closely positioned elements reside near a cavity that is shown by multiple studies to be a likely site of action for allosteric modulators, one of which is currently in use as an FDA‐approved anticonvulsant. These structural elements are capable of controlling gating of the pore, and appear to permit some modulators bound within the cavity to also alter permeation properties. This creates a new precedent whereby features of the channel pore can be modulated by exogenous drugs that bind outside the pore. The convergence of structural, genetic, biophysical and pharmacological approaches is a powerful means to gain insight into the complex biological processes defined by neurotransmitter receptor function.
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Biologically mediated silicification of marine cyanobacteria and implications for the Proterozoic fossil record
Authors: Moore Kelsey R. , Pajusalu Mihkel , Gong Jian , Sojo Victor , Matreux Thomas , Braun Dieter , Bosak Tanja 
Published: May 2020

Abstract
Silicification was a major mode of fossilization in Proterozoic peritidal environments, but marine silica concentrations and the chemical and biological mechanisms that drove microbial silicification and formation of early diagenetic chert in these environments remain poorly constrained. Here, we use taphonomy experiments to demonstrate that photosynthetically active cyanobacteria that are morphologically analogous to the oldest cyanobacterial fossil, Eoentophysalis, mediate the formation of magnesium-rich amorphous silica in seawater that is undersaturated with respect to silica. These results show that microbes in Proterozoic tidal environments may have mediated their own silicification at lower silica concentrations than previously assumed.
Tectonic stress controls saucer-shaped sill geometry and emplacement mechanism
Authors: Walker R.J. , Gill S.P.A. 
Published: May 2020

AbstractSaucer-shaped sills are common in sedimentary basins worldwide. The saucer shape relates to asymmetric sill-tip stress distributions during intrusion caused by bending of the overburden. Most saucer-shaped sill models are constructed using a magma-analogue excess source pressure (Po) to drive host-rock failure, but without tectonic stress. Here we present axisymmetric finite-element simulations of radially propagating sills for a range of tectonic stress (σr) conditions, from horizontal tension (σr &lt; 0) to horizontal compression (0 &lt; σr). Response to σr falls into four regimes, based on sill geometry and failure mode of the host rock. The regimes are considered in terms of the ratio of tectonic stress versus magma source pressure R = σr/Po: (I) initially seeded sills transition to a dike during horizontal extension (R &lt; 0); (II) with R increasing from 0 towards 1 (compressive σr), sill base length increases and sill incline decreases; (III) where 1 &lt; R &lt; 2, sill base length relatively decreases and sill incline increases; and (IV) where R &gt; 2, sills grow as inclined sheets. Sills in regimes I–III grow dominantly by tensile failure of the host rock, whereas sills in regime IV grow by shear failure of the host rock. Varying σr achieves a range of sill geometries that match natural sill profiles. Tectonic stress therefore represents a primary control on saucer-shaped sill geometry and emplacement mechanism.
A 23 m.y. record of low atmospheric CO2
Authors: Cui Ying , Schubert Brian A. , Jahren A. Hope 
Published: May 2020

AbstractCurrent atmospheric CO2 concentration is known to be higher than it has been during the past ∼800 k.y. of Earth history, based on direct measurement of CO2 within ice cores. A comparison to the more ancient past is complicated by a deficit of CO2 proxies that may be applied across very long spans of geologic time. Here, we present a new CO2 record across the past 23 m.y. of Earth history based on the δ13C value of terrestrial C3 plant remains, using a method applicable to the entire ∼400 m.y. history of C3 photosynthesis on land. Across the past 23 m.y., CO2 likely ranged between ∼230 ppmv and 350 ppmv (68% confidence interval: ∼170–540 ppm). CO2 was found to be highest during the early and middle Miocene and likely below present-day levels during the middle Pliocene (84th percentile: ∼400 ppmv). These data suggest present-day CO2 (412 ppmv) exceeds the highest levels that Earth experienced at least since the Miocene, further highlighting the present-day disruption of long-established CO2 trends within Earth’s atmosphere.
Disparities in baseline neurocognitive testing for student concussion management in Massachusetts high schools
Authors: Campbell Julia , Howland Jonathan , Hess Courtney , Nelson Kerrie , Stern Robert A , Torres Alcy , Olshaker Jonathan 
Published: May 2020

PurposeThere is evidence of socioeconomic disparities with respect to the implementation of student-sports concussion laws nationally. The purpose of this study was to examine school sociodemographic characteristics associated with the provision of computerised baseline neurocognitive testing (BNT) in Massachusetts (MA) high schools, and to assess whether the scope of testing is associated with the economic status of student populations in MA.MethodsA cross-sectional secondary analysis of surveys conducted with MA athletic directors (n=270) was employed to investigate school characteristics associated with the provision of BNT. Correlation and regression analyses were used to assess whether the scope of testing is associated with the economic status of student populations in MA.ResultsThe scope of BNT was independently associated with the economic disadvantage rate (EDR) of the student population (β=−0.02, p=0.01); whether or not the school employs an athletic trainer (AT) (β=0.43, p=0.03); and school size (β=−0.54, p=0.03). In a multivariable regression model, EDR was significantly associated with the scope of baseline testing, while controlling for AT and size (β=−0.01, p=0.03, adj-R2=0.1135).ConclusionAmong public high schools in MA, disparities in the provision of BNT for students are associated with the economic characteristics of the student body. Schools that have a greater proportion of low-income students are less likely to provide comprehensive BNT. The clinical implications of not receiving BNT prior to concussion may include diminished quality of postconcussive care, which can have short-term and long-term social, health-related and educational impacts.
Computed tomographic myocardial mass compared with invasive myocardial perfusion measurement
Authors: Keulards Daniëlle C J , Fournier Stephane , van 't Veer Marcel , Colaiori Iginio , Zelis Jo M , El Farissi Mohamed , Zimmermann Frederik M , Collet Carlos , De Bruyne Bernard , Pijls Nico H J 
Published: May 2020

ObjectiveThe prognostic importance of a coronary stenosis depends on its functional severity and its depending myocardial mass. Functional severity can be assessed by fractional flow reserve (FFR), estimated non-invasively by a specific validated CT algorithm (FFRCT). Calculation of myocardial mass at risk by that same set of CT data (CTmass), however, has not been prospectively validated so far. The aim of the present study was to compare relative territorial-based CTmass assessment with relative flow distribution, which is closely linked to true myocardial mass.MethodsIn this exploratory study, 35 patients with (near) normal coronary arteries underwent CT scanning for computed flow-based CTmass assessment and underwent invasive myocardial perfusion measurement in all 3 major coronary arteries by continuous thermodilution. Next, the mass and flows were calculated as relative percentages of total mass and perfusion.ResultsThe mean difference between CTmass per territory and invasively measured myocardial perfusion, both expressed as percentage of total mass and perfusion, was 5.3±6.2% for the left anterior descending territory, −2.0±7.4% for the left circumflex territory and −3.2±3.4% for the right coronary artery territory. The intraclass correlation between the two techniques was 0.90.ConclusionsOur study shows a close relationship between the relative mass of the perfusion territory calculated by the specific CT algorithm and invasively measured myocardial perfusion. As such, these data support the use of CTmass to estimate territorial myocardium-at-risk in proximal coronary arteries.
Endocarditis risk with bioprosthetic and mechanical valves: systematic review and meta-analysis
Authors: Anantha-Narayanan Mahesh , Reddy Yogesh N V , Sundaram Varun , Murad Mohammad Hassan , Erwin Patricia J , Baddour Larry M , Schaff Hartzell V , Nishimura Rick A 
Published: May 2020

ObjectiveBioprosthetic valves are being used with increased frequency for valve replacement, with controversy regarding risk:benefit ratio compared with mechanical valves in younger patients. However, prior studies have been too small to provide comparative estimates of less common but serious adverse events such as infective endocarditis. We aimed to compare the incidence of infective endocarditis between bioprosthetic valves and mechanical valves.MethodsWe searched PubMed, Cochrane, EMBASE, Scopus and Web of Science from inception to April 2018 for studies comparing left-sided aortic and mitral bioprosthetic to mechanical valves for randomised trials or observational studies with propensity matching. We used random-effects model for our meta-analysis. Our primary outcome of interest was the rate of infective endocarditis at follow-up.Results13 comparison groups with 43 941 patients were included. Mean age was 59±7 years with a mean follow-up of 10.4±5.0 years. Patients with bioprosthetic valves had a higher risk of infective endocarditis compared with patients receiving mechanical valves (OR 1.59, 95% CI 1.35 to 1.88, p<0.001) with an absolute risk reduction of 9 per 1000 (95% CI 6 to 14). Heterogeneity within the included studies was low (I2=0%). Exclusion of the study with maximum weight did not change the results of the analysis (OR 1.57, 95% CI 1.14 to 2.17, p=0.006). A meta-regression of follow-up time on incidence of infective endocarditis was not statistically significant (p=0.788) indicating difference in follow-up times did not alter the pooled risk of infective endocarditis.ConclusionsBioprosthetic valves may be associated with a higher risk of infective endocarditis. These data should help guide the discussion when deciding between bioprosthetic and mechanical valves in individual patients.
Fully automated intracranial aneurysm detection and segmentation from digital subtraction angiography series using an end-to-end spatiotemporal deep neural network
Authors: Jin Hailan , Geng Jiewen , Yin Yin , Hu Minghui , Yang Guangming , Xiang Sishi , Zhai Xiaodong , Ji Zhe , Fan Xinxin , Hu Peng , He Chuan , Qin Lan , Zhang Hongqi 
Published: May 2020

BackgroundIntracranial aneurysms (IAs) are common in the population and may cause death.ObjectiveTo develop a new fully automated detection and segmentation deep neural network based framework to assist neurologists in evaluating and contouring intracranial aneurysms from 2D+time digital subtraction angiography (DSA) sequences during diagnosis.MethodsThe network structure is based on a general U-shaped design for medical image segmentation and detection. The network includes a fully convolutional technique to detect aneurysms in high-resolution DSA frames. In addition, a bidirectional convolutional long short-term memory module is introduced at each level of the network to capture the change in contrast medium flow across the 2D DSA frames. The resulting network incorporates both spatial and temporal information from DSA sequences and can be trained end-to-end. Furthermore, deep supervision was implemented to help the network converge. The proposed network structure was trained with 2269 DSA sequences from 347 patients with IAs. After that, the system was evaluated on a blind test set with 947 DSA sequences from 146 patients.ResultsOf the 354 aneurysms, 316 (89.3%) were successfully detected, corresponding to a patient level sensitivity of 97.7% at an average false positive number of 3.77 per sequence. The system runs for less than one second per sequence with an average dice coefficient score of 0.533.ConclusionsThis deep neural network assists in successfully detecting and segmenting aneurysms from 2D DSA sequences, and can be used in clinical practice.
Intervertebral disc disease and aortic thromboembolism are the most common causes of acute paralysis in dogs and cats presenting to an emergency clinic
Authors: Rossi Graham , Stachel Alexandra , Lynch Alex M , Olby Natasha J 
Published: May 2020

BackgroundAcute paralysis is a common presentation in small animal emergency clinics, but the aetiological prevalence has not been reported. Knowledge of diagnosis frequency aids prioritisation of differential diagnoses, facilitates resource planning and clinical trial design.MethodsMedical records from NC State Veterinary Hospital Emergency Room were searched over a five‐year period to identify cases presenting with acute non‐ambulatory paraparesis or paralysis. Signalment and diagnosis category were extracted.ResultsAcute paralysis was the presenting problem in 845 of 21,535 (3.9 per cent) dogs and 66 of 4589 (1.4 per cent) cats admitted over this period. Intervertebral disc disease (IVDD) was the most common cause (608 of 845; 72 per cent) in dogs, followed by vascular disease (34 of 845; 4.0 per cent). Other diagnostic categories accounted for the remaining 20 per cent. Dachshunds were the most common breed (263 of 845; 31.1 per cent), then Labrador retrievers (57 of 845; 6.7 per cent). In cats, aortic thromboembolism (ATE) was the most common diagnosis, occurring in 40 of 66 (60.6 per cent), followed by IVDD (7 of 66; 10.6 per cent). Other diagnostic categories accounted for 30.3 per cent. Six of 845 (0.7 per cent) dogs and two of 66 (3 per cent) cats were categorised as pseudoparalysis with a non‐neurological diagnosis.ConclusionsIVDD and ATE are the overwhelming causes of acute paralysis in dogs and cats, respectively, with approximately 28 per cent of dogs and 40 per cent of cats having a different diagnosis.
Electrically evoked force loss of the knee extensors is equivalent for young and old females and males
Authors: Yacyshyn Alexandra F. , McNeil Chris J. 
Published: May 2020

Data are scant on sex-related differences for electrically evoked contractions, which assess intrinsic contractile properties while limiting spinal and supraspinal adaptations to mitigate fatigue. Furthermore, the few studies that exist use stimulus frequencies considerably higher than the natural motor unit discharge rate for the target force. The purpose of this study was to compare force loss to electrically evoked contractions at a physiological stimulus frequency among young females (n = 12), young males (n = 12), old females (n = 11), and old males (n = 11). The quadriceps of the dominant leg were fatigued by 3 min of intermittent transcutaneous muscle belly stimulation (15 Hz stimulus train to initially evoke 25% of maximal voluntary force). Impairment of tetanic contractile impulse (area under the curve) did not differ between sexes for young or old adults or between age groups, with a pooled value of 55.2% ± 12.4% control at the end of fatigue. These data contrast with previous findings at 30 Hz, when the quadriceps of females had greater fatigue resistance than males for young and old adults. The present results highlight the impact stimulus frequency has on intrinsic fatigability of muscle; the findings have implications for future fatigue paradigms and treatment approaches when utilizing electrical stimulation for rehabilitation. Novelty Fatigue was not different between sexes with a stimulation frequency comparable to discharge rates during voluntary contractions. These results highlight that stimulus frequency not only influences fatigue development but also between-group differences.
Effect of water and air injection on reduction of bend scour
Authors: Tamoradi Zeinab , Ahadiyan Javad 
Published: May 2020

In the proposed method, air and water were injected into the 180° bend flow from both sides of a perforated tube to overcome curvature-induced secondary flows by creating a non-rigid barrier. The experimental results showed that the secondary flows were deviated from the outer bend causing a reduction in the maximum scour depth along the bend. The navigable width may also be increased by shifting the maximum scour depth from the outer wall to the centerline. On the other hand, the maximum scour depth was reduced by decreasing the distance between the perforated tube and the outer wall. For example, the maximum scour depth in the water and air injection main experiments at 130° section of the bend and two tube distances of 2.5 cm and 5 cm decreased by 88%, 91%, 63%, and 45%, respectively. With the increase in the Froude numbers, the maximum scour depth has increased.
Confronting experimental data with heavy-ion models: Rivet for heavy ions
Authors: Bierlich Christian , Buckley Andy , Christensen Christian Holm , Christiansen Peter Harald Lindenov , Duncan Cody B. , Grosse-Oetringhaus Jan Fiete , Karczmarczyk Przemyslaw , Kirchgaeßer Patrick , Klein Jochen , Lönnblad Leif , Preghenella Roberto , Rasmussen Christine O. , Stefaniak Maria , Vislavicius Vytautas 
Published: May 2020

AbstractThe Rivet library is an important toolkit in particle physics, and serves as a repository for analysis data and code. It allows for comparisons between data and theoretical calculations of the final state of collision events. This paper outlines several recent additions and improvements to the framework to include support for analysis of heavy ion collision simulated data. The paper also presents examples of these recent developments and their applicability in implementing concrete physics analyses.
The soft-gluon limit and the infrared enhancement of the quark-gluon vertex
Authors: Oliveira Orlando , Frederico Tobias , de Paula Wayne 
Published: May 2020

AbstractThe Schwinger–Dyson quark equation (SDE) combined with results from lattice simulation for the propagators are used to obtain information on the quark-gluon vertex, taking into account the recent full QCD lattice results for the soft-gluon limit. Its inclusion leads to a clear enhancement of the infrared quark-gluon vertex. We also find that the relative contribution of the quark-ghost kernel to the quark-gluon vertex in the infrared region does not follow the rules from the perturbative analysis of the ultraviolet region. This shows that for QCD the intuition based on perturbation theory does not apply to the full momentum range. The framework developed in the current work provides analytical expressions for all the longitudinal components of vertex taken into account.
Tectonic terranes underlying the present-day Caribbean plate: their tectonic origin, sedimentary thickness, subsidence histories and regional controls on hydrocarbon resources
Authors: Romito Sean , Mann Paul 
Published: May 2020

Abstract
Thick sedimentary cover (≤16 km), vintage seismic and disparate crustal terranes have hindered understanding of the basement underlying the Caribbean plate. The plate formed by Early Cretaceous to Miocene amalgamation of four crustal types: the Caribbean Large Igneous Province oceanic plateau; the Chortis continental block; the related Great Arc of the Caribbean and Siuna/Mesquito Composite Oceanic Terranes island arc blocks; and the Colombian and Venezuelan basin oceanic crust. We characterize each terrane through interpretation of surface geology, 62 000-line-km of 2D seismic reflection data, 366 seismic refraction stations, 47 wells, 74 basement samples, 2D forward modelling, magnetic and gravity anomaly grids, and integration of previous studies.
Basins overlying island arc crust are small, fault-bounded and deep, while on continental crust, they are broader and shallower. Strongly flexed oceanic and oceanic plateau crust along amagmatic subduction zones on the southern and northeastern edges of the Caribbean plate produce the largest and deepest sediment-filled basins.
Areas of proven hydrocarbon source rocks and mapped seeps are associated with continental and island arc terranes in the western Caribbean plate, while organically-rich, but immature, Late Cretaceous source rocks occur across the more elevated areas of the central and eastern Caribbean plate interior.