bluuebunny/crossref_metadata_2025 huggingface dataset:
The impact of rent seeking on social infrastructure and productivity
Authors: del Río Fernando
Published: March 2021

I develop a neoclassical growth model in which rent seeking impacts negatively on productivity and welfare because it discourages the accumulation of social infrastructure. I estimate the fraction of resources wasted in rent seeking for a sample of 141 countries. On average, countries in the first (respectively, last) decile of the distribution of the estimated rent‐seeking intensity devote around (respectively, ) of output to rent‐seeking and have (respectively, ) of output per capita and (respectively, ) of consumption per capita of a country without rent seeking. Moreover, around one quarter of the drop in consumption per capita caused by rent seeking is due to its negative impact on the accumulation of social infrastructure and the remaining three quarters are due to the waste of resources.
Financial market spillovers of U.S. monetary policy shocks
Authors: Ha Jongrim
Published: March 2021

This paper investigates the cross‐border propagation of U.S. monetary policy shocks to the financial markets of five open countries—Australia, Canada, New Zealand, South Korea, and the United Kingdom—from 2000 to 2017. I estimate the structural VAR models that consist of multiple high‐frequency financial variables, in which the impacts of foreign (U.S.) and local monetary policy shocks are estimated jointly, using a novel set of external instruments. I include a wide range of domestic, U.S., and global endogenous variables to reflect the various channels of shock transmission. I draw four main findings from the empirical results. First, the foreign exchange rates respond flexibly to domestic and foreign monetary shocks, as the overshooting theory predicts. Second, despite the reactions in foreign exchange rates, U.S. monetary shocks propagate strongly to domestic financial markets in other countries, possibly reflecting the correlated term and risk premiums across countries. Third, while the results support the significant transmission of domestic monetary policies by the central banks in the countries, U.S. monetary shocks exhibit greater and more persistent impacts on domestic asset prices than the domestic shocks. Finally, a set of counterfactual experiments reveal that the international transmission of U.S. monetary policy shocks operate through several channels, including global financial sentiments, U.S. asset prices (both equity prices and bond yields), and foreign exchange rates.
On Optimal Rerandomization Designs
Authors: Johansson Per , Rubin Donald B. , Schultzberg Mårten
Published: March 2021

Blocking is commonly used in randomized experiments to increase efficiency of estimation. A generalization of blocking removes allocations with imbalance in covariate distributions between treated and control units, and then randomizes within the remaining set of allocations with balance. This idea of rerandomization was formalized by Morgan and Rubin (Annals of Statistics, 2012, 40, 1263–1282), who suggested using Mahalanobis distance between treated and control covariate means as the criterion for removing unbalanced allocations. Kallus (Journal of the Royal Statistical Society, Series B: Statistical Methodology, 2018, 80, 85–112) proposed reducing the set of balanced allocations to the minimum. Here we discuss the implication of such an ‘optimal’ rerandomization design for inferences to the units in the sample and to the population from which the units in the sample were randomly drawn. We argue that, in general, it is a bad idea to seek the optimal design for an inference because that inference typically only reflects uncertainty from the random sampling of units, which is usually hypothetical, and not the randomization of units to treatment versus control.
Accuracy of slender body theory in approximating force exerted by thin fiber on viscous fluid
Authors: Mori Yoichiro , Ohm Laurel
Published: March 2021

We consider the mapping properties of the integral operator arising in nonlocal slender body theory (SBT) for the model geometry of a straight, periodic filament. It is well known that the classical singular SBT integral operator suffers from high wavenumber instabilities, making it unsuitable for approximating the slender body inverse problem, where the fiber velocity is prescribed and the integral operator must be inverted to find the force density along the fiber. Regularizations of the integral operator must therefore be used instead. Here, we consider two regularization methods: spectral truncation and the ‐regularization of Tornberg and Shelley (2004). We compare the mapping properties of these approximations to the underlying partial differential equation (PDE) solution, which for the inverse problem is simply the Stokes Dirichlet problem with data constrained to be constant on cross sections. For the straight‐but‐periodic fiber with constant radius , we explicitly calculate the spectrum of the operator mapping fiber velocity to force for both the PDE and the approximations. We prove that the spectrum of the original SBT operator agrees closely with the PDE operator at low wavenumbers but differs at high frequencies, allowing us to define a truncated approximation with a wavenumber cutoff . For both the truncated and ‐regularized approximations, we obtain rigorous ‐based convergence to the PDE solution as : A fiber velocity with regularity gives convergence, while a fiber velocity with at least regularity yields convergence. Moreover, we determine the dependence of the ‐regularized error estimate on the regularization parameter .
Tongue carcinoma as a secondary malignancy in a 17‐year‐old leukemia survivor: A case report
Authors: de Mendonça Regina Maria Holanda , Cappellaro Katia Maria Coutinho , Gueiros Luiz Alcino , Cardinalli Izilda Aparecida , Arboleda Lady Paola Aristizábal , Santos‐Silva Alan Roger
Published: March 2021

Pediatric hematologic malignancies present an elevated survival rate, and these survivors may experience long‐term complications, including secondary malignancies. This case describes a 17‐year‐old female patient previously treated for acute lymphoblastic leukemia (ALL) who developed a squamous cell carcinoma (SCC, T2N0M0) of the lateral border of the tongue diagnosed during dental follow‐up 2 years and 9 months after the conclusion of ALL therapy (GBTLILLA99 protocol). The patient underwent exclusive surgical resection for the tongue SCC and is free of disease 11 years after the surgery. The current case report highlights the importance of monitoring the oral health of childhood cancer survivors. As part of a multidisciplinary team, our directives include counseling to avoid carcinogenic exposures.
Deontic Concepts and Their Clash in Mīmāṃsā: Towards an Interpretation
Authors: Freschi Elisa , Pascucci Matteo
Published: March 2021

The article offers an overview of the deontic theory developed by the philosophical school of Mīmāṃsā, which is, and has been since the last centuries BCE, the main source of normative concepts in Sanskrit thought. Thus, the Mīmāṃsā deontics is interesting for any historian of philosophy and constitutes a thought‐provoking occasion to rethink deontic concepts, taking advantage of centuries of systematic reflections on these topics. Some comparison with notions currently used in Euro‐American normative theories and metaethical principles is offered in order to show possible points of contact and deep divergences. In more detail, after an introduction explaining the methodology and aims of our work, we discuss how Mīmāṃsā authors distinguished and defined some fundamental deontic concepts, such as different types of prescriptions and prohibitions. We then discuss how Mīmāṃsā authors approached the problem of conflicts among commands without jeopardising the validity of the normative text issuing them. In the second part of the article we introduce our formal apparatus, which is construed around the main taxonomic and conceptual distinctions used in the first part. Our formal rendering captures the most important features of the Mīmāṃsā theory and can thus serve as a concise and rigorous presentation of it for scholars working in deontic logic.
Origin and Evolution of the W mineralization in the Intrusion-related Hydrothermal Deposits of the Cerro Áspero Mining District, Sierras Pampeanas, Argentina
Authors: González Chiozza Sebastián
Published: March 2021

The Cerro Áspero Mining District (CAMD) is located at the Sierras Pampeanas of central Argentina and hosts significant intrusion-related wolframite mineralization. The ore deposits are associated to hydrothermal quartz veins and breccias, hosted by granitoids and metamorphic rocks at the northern contact zone of the Devonian post-orogenic Cerro Áspero Batholith (CAB). The physico-chemical conditions of the different mineralization styles are yet not totally understood, and aiming to deliver a metallogenetic model, the petrography and composition of the main ore and gangue minerals were investigated, and fluid inclusion and stable isotope studies were performed in quartz, muscovite, wolframite, apatite, pyrite, molybdenite, chalcopyrite, and galena. The integrated results revealed that the CAMD ore deposits were generated within the cooling period of the Cerro Áspero Batholith, throughout three late to post-magmatic hydrothermal mineralizing stages. Based on fluid inclusion studies and stable isotope processed data, it was found that the fluids of the first two stages were probably derived from a magmatic source, whereas the third stage solutions would have been originated from meteoric waters. The temperature of the system at the beginning of the hydrothermal phase, was estimated at 384°C; thereafter, the calculated values suggest a decreasing thermal path. Chemical analyses of wolframite showed that the CAMD ore deposit’s evolution was signed by initial formation of ferberite, and subsequently evolved with an increasing H/F ratio that conduced to hübnerite precipitation in the final stage.
Effect of Tip Clearance on Rotating Stall in a Mixed-Flow Pump
Authors: Li Wei , Ji Leilei , Li Enda , Zhou Ling , Agarwal Ramesh K.
Published: March 2021

The non-uniform disturbance in the circumferential direction is the essential cause of the occurrence of rotating stall in a turbomachinery. In order to study the effect of tip clearance leakage flow on rotating stall, the mixed-flow pump models with different tip clearances were numerically calculated, and then the energy performance curves and internal flow structures were obtained and compared. The results show that the pump efficiency and the internal flow field of the numerical calculation are in good agreement with the experimental results. A saddle region appeared in the energy performance curves of the three tip clearances, and with the decrease of clearance, the head and efficiency of the mixed-flow pump increased to varying degrees, but the critical stall point shifted to the large flowrate, and the stable operating range of the mixed-flow pump decreased, which indicating that the mixed-flow pumps were easier to stall under small tip clearance. Under the deep stall condition, the influence of the leakage flow on the end wall area increases gradually with the decrease of clearance. Under the small clearance, the leakage flow flows away from the suction surface for a certain distance to form a number of tip leakage vortex strips with the mainstream action, overflows the leading edge of the next blade, and then flows downstream into different flow passages, aggravating backflow and secondary flow separation at the blade inlet, which seriously damaged the spatial structure of the inlet flow. This resulted in the earlier occurrence of stall. With the increase of tip clearance, the tip leakage vortex develops along the radial direction to the middle of the flow channel and serious flow separation phenomenon occurs in the downstream channel, which induces the deep stall. Under the 0.8 mm tip clearance, the whole impeller outlet passage is almost blocked by the backflow of the guide vane inlet, and a deep stall was induced.
Influence of Boundary Layer Skew on the Tip Leakage Vortex of an Axial Compressor Stator
Authors: Koppe Björn , Lange Martin , Mailach Ronald
Published: March 2021

For an axial compressor stator with tip gap, the boundary layer (BL) in the hub endwall region has a significant influence on the development and progression of the tip leakage vortex. Herein, the so-called BL skew, which develops through relative motion of the hub, is of particular interest. Therefore, experimental and numerical investigations of a single axial compressor stator row with varying tip gap height (tip gap height/chord length =2.0%|5.4%|6.7%) have been conducted. Comparing cases with rotating or stationary hub endwall segments upstream of the examined vanes allowed to determine the effect of the skewed and un-skewed inflow BL. The steady-state flow fields up- and downstream of the stator row were measured using five-hole pressure probes. For validation and to improve the understanding of the existing flow phenomena, 3D-Reynolds-averaged Navier–Stokes (RANS) CFD simulations using a commercial flow solver were carried out. Furthermore, analog cases with no tip gap were examined and considered in the comparisons to extend the knowledge on this BL characteristic. The results show that the BL skew has a major influence on the trajectory and size of the tip leakage vortex for the cases with tip clearance. The effect of reduction of the produced losses decreases with increasing tip gap height.
The Effect of a Coupling Agent on the Impact Behavior of Flax Fiber Composites
Authors: Kaboglu Cihan , Liu Jun , Liu Haibao , Russo Pietro , Simeoli Giorgio , Lopresto Valentina , Dear John P. , Maharaj Chris
Published: March 2021

The effects of a coupling agent on the behavior of flax fiber-reinforced composites have been investigated by testing the specimens under both quasi-static (QS) indentation and high-velocity impact loading. The specimens are manufactured embedding a commercial flax fiber fabric in a polypropylene (PP) matrix, neat and premodified with a maleic anhydride-grafted PP, the latter acting as a coupling agent to enhance the interfacial adhesion. QS compressive tests were performed using a dynamometer testing machine equipped with a high-density polyethylene indenter having the same geometry of the projectile employed in the impact tests. The impact tests were conducted setting three different impact velocities. Digital image correlation maps of out-of-plane displacement were employed to compare the specimens with and without the coupling agent. The QS testing results indicate that the coupling agent has an enhancing influence on the bending stiffness of tested flax composites. The testing results show that the coupling agent improves the mechanical behavior by decreasing the out-of-plane displacement under impact loading. This approach gives rise to new materials potentially useful for applications where impact performance is desired while also providing an opportunity for the incorporation of natural fibers to produce a lightweight composite.
A Finite Element Study of Large Strain Extrusion Machining Using Modified Zerilli–Armstrong Constitutive Relation
Authors: Gurusamy Muralimohan , Palaniappan Karthik , Murthy H. , Rao Balkrishna C.
Published: March 2021

The objective of this work is to study the performance of modified Zerilli–Armstrong constitutive relation proposed in our previous study for the finite element modeling of a severe plastic deformation technique called large strain extrusion machining. The modified Zerilli–Armstrong constitutive relation is implemented in a finite element model of large strain extrusion machining of Inconel 718 to analyze the influence of process parameters, i.e., the chip compression ratio and tool–chip friction, on deformation, effective strain distribution, and hydrostatic pressure distribution along the extruded chip. The predicted strain values for different chip compression ratios were validated by comparison with those obtained through an analytical model. The finite element predictions also served as a guideline in designing the large strain extrusion-machining setup on which experiments were conducted to generate Inconel 718 foils with superior mechanical properties. The predicted limits of chip compression ratio were in close agreement with experimentally realizable values. Furthermore, the predicted strain distribution through the thickness of the chip was validated with the results of hardness measurement tests. Microstructural characterization of the Inconel 718 foils was carried out by using both optical and transmission-electron microscopic studies in order to reveal the presence of fine-grain structures. The validations showed the effectiveness of the modified Zerilli–Armstrong constitutive relation in modeling large strain extrusion machining—a variant of the conventional machining process.
Numerical Investigation of Thermal Performance of Key Components of Electric Vehicles Using Nucleate Boiling
Authors: P I Shyamkumar , Singh Suneet , Srivastava Atul , Visaria Milan
Published: March 2021

An efficient thermal management system is desirable for improving the performance of key components of electric vehicle (EV), such as battery packs and insulated-gate bipolar transistors (IGBTs). This paper investigates the application of single bubble nucleate boiling heat transfer in battery and IGBT component cooling pack. A semi-mechanistic flow boiling model, which combines four main submodels i.e., phase change model, micro-region model, Marangoni model, and contact angle model, is developed to get the insight of various subprocesses like bubble inception, growth, departure, scavenging effect while the bubble departs, and condensation. For model validation, simulations are carried out for single bubble flow boiling in a vertical rectangular channel and compared against the experimental data available in the literature. Thereafter, simulations are carried out for the battery and IGBT cooling pack to understand the physical phenomena associated with nucleate boiling in such systems. The choice of a single vapor bubble vis-à-vis multiple bubbles has been based on the objective of validating the developed numerical model. An enhancement of ∼30% in heat transfer is achieved for both battery and IGBT components when the system is subjected to a nucleate boiling cooling regime as compared to a conventional single-phase convection cooling system. Nusselt number variation due to the single bubble movement along the coolant path is studied in detail for both serpentine-shaped cooling path in a battery and straight flow path in an IGBT. Moreover, the influence of Reynolds number over bubble dynamics is analyzed.
Cuttlefish bone (cuttlebone), by near-ambient pressure XPS
Authors: Avval Tahereh G. , Chapman Sean C. , Carver Victoria , Dietrich Paul , Thißen Andreas , Linford Matthew R.
Published: March 2021

Near ambient pressure-x-ray photoelectron spectroscopy (NAP-XPS) is a less traditional form of XPS that allows samples to be analyzed at relatively high pressures, i.e., at greater than 2500 Pa. NAP-XPS can probe moderately volatile liquids, biological samples, porous materials, and/or polymeric materials that outgas significantly. In this submission, we show the survey, Ca 2p, C 1s, O 1s, and N 1s NAP-XPS spectra of two biological samples (cuttlefish bones in their native state and implanted with nitrogen ions), which are materials that would be difficult to analyze by conventional XPS. The measurements were performed at 100 Pa in ambient air to compensate for surface charging. Peak fits of the Ca 2p, C 1s, and N 1s narrow scans are presented.
Time Course of Neuromuscular, Hormonal, and Perceptual Responses Following Moderate- and High-Load Resistance Priming Exercise
Authors: Harrison Peter W. , James Lachlan P. , Jenkins David G. , McGuigan Michael R. , Schuster Robert W. , Kelly Vincent G.
Published: March 2021

Purpose: The aim of this study was to map responses over 32 hours following high-load (HL) and moderate-load (ML) half-squat priming. Methods: Fifteen participants completed control, HL (87% 1RM), and ML (65% 1RM) activities in randomized, counterbalanced order. Countermovement jump (CMJ), squat jump (SJ), saliva testosterone, saliva cortisol, and perceptual measures were assessed before and 5 minutes, 8 hours, 24 hours, and 32 hours after each activity. Results are presented as percentage change from baseline and 95% confidence interval (CI). Cliff delta was used to determine threshold for group changes. Results: SJ height increased by 4.5% (CI = 2.2–6.8, Cliff delta = 0.20) 8 hours following HL. CMJ and SJ improved by 6.1% (CI = 2.1–7.8, Cliff delta = 0.27) and 6.5% (CI = 1.2–11.8, Cliff delta = 0.30), respectively, 32 hours after ML. No clear diurnal changes in CMJ or SJ occurred 8 hours following control; however, increases of 3.9% (CI = 2.9–9.2, Cliff delta = 0.26) and 4.5% (CI = 0.9–8.1, Cliff delta = 0.24), respectively, were observed after 32 hours. Although diurnal changes in saliva hormone concentration occurred (Cliff delta = 0.37–0.92), the influence of priming was unclear. Perceived “physical feeling” was greater 8 hours following HL (Cliff delta = 0.36) and 32 hours after ML and control (Cliff delta = 0.17–0.34). Conclusions: HL priming in the morning may result in small improvements in jump output and psychophysiological state in the afternoon. Similar improvements were observed in the afternoon the day after ML priming.
Monitoring Rating of Perceived Exertion Time in Zone: A Novel Method to Quantify Training Load in Elite Open-Water Swimmers?
Authors: Ieno Cristian , Baldassarre Roberto , Pennacchi Maddalena , La Torre Antonio , Bonifazi Marco , Piacentini Maria Francesca
Published: March 2021

Purpose: To analyze training-intensity distribution (TID) using different independent monitoring systems for internal training load in a group of elite open-water swimmers. Methods: One hundred sixty training sessions were monitored in 4 elite open-water swimmers (2 females and 2 males: 23.75 [4.86] y, 62.25 [6.18] kg, 167 [6.68] cm) during 5 weeks of regular training. Heart-rate-based methods, such as time in zone (TIZ), session goal (SG), and hybrid (SG/TIZ), were used to analyze TID. Similarly to SG/TIZ, a new hybrid approach, the rating of perceived exertion (RPE)/TIZ for a more accurate analysis of TID was used. Moreover, based on the 3-zone model, the session ratings of perceived exertion of the swimmers and the coach were compared. Results: Heart-rate- and RPE-based TID methods were significantly different in quantifying Z1 (P = .012; effect size [ES] = 0.490) and Z2 (P = .006; ES = 0.778), while no difference was observed in the quantification of Z3 (P = .428; ES = 0.223). The heart-rate-based data for Z1, Z2, and Z3 were 83.2%, 7.4%, and 8.1% for TIZ; 80.8%, 8.3%, and 10.8% for SG/TIZ; and 55%, 15.6%, and 29.4% for SG. The RPE-based data were 70.9%, 19.9%, and 9.2% for RPE/TIZ% and 41.2%, 48.9%, and 9.7% for the session rating of perceived exertion. No differences were observed between the coach’s and the swimmers’ session ratings of perceived exertion in the 3 zones (Z1: P = .663, ES = −0.187; Z2: P = .110, ES = 0.578; Z3: P = .149, ES = 0.420). Conclusion: Using RPE-based TID methods, Z2 was significantly larger compared with Z1. These results show that RPE-based TID methods in elite open-water swimmers are affected by both intensity and volume.
Spontaneous Selection of
Cryptosporidium
Drug Resistance in a Calf Model of Infection
Authors: Hasan Muhammad M. , Stebbins Erin E. , Choy Robert K. M. , Gillespie J. Robert , de Hostos Eugenio L. , Miller Peter , Mushtaq Aisha , Ranade Ranae M. , Teixeira José E. , Verlinde Christophe L. M. J. , Sateriale Adam , Zhang Zhongsheng , Osbourn Damon M. , Griggs David W. , Fan Erkang , Buckner Frederick S. , Huston Christopher D.
Published: March 2021

The intestinal protozoan
Cryptosporidium
is a leading cause of diarrheal disease and mortality in young children. There is currently no fully effective treatment for cryptosporidiosis, which has stimulated interest in anticryptosporidial development over the last ∼10 years, with numerous lead compounds identified, including several tRNA synthetase inhibitors.
Exopolysaccharide Anchoring Creates an Extreme Resistance to Sedimentation
Authors: Kessler Nickolas G. , Caraballo Delgado David M. , Shah Neel K. , Dickinson Jeff A. , Moore Sean D.
Published: March 2021

Bacteria can partition in aqueous environments between surface-dwelling, planktonic, sedimentary, and biofilm forms. Residence in each location provides an advantage depending on nutritional and environmental stresses, and a community of a single species is often observed to be distributed throughout two or more of these niches.
Large Metabolic Rewiring from Small Genomic Changes between Strains of Shigella flexneri
Authors: Doore Sarah M. , Subramanian Sundharraman , Tefft Nicholas M. , Morona Renato , TerAvest Michaela A. , Parent Kristin N.
Published: March 2021

Shigella
causes millions of dysentery cases worldwide, primarily affecting children under 5 years old. Despite active research in developing vaccines and new antibiotics, relatively little is known about the variation of physiology or metabolism across multiple isolates.
Regulatory Involvement of the PerR and SloR Metalloregulators in the Streptococcus mutans Oxidative Stress Response
Authors: Ruxin Talia R. , Schwartzman Julia A. , Davidowitz Cleo R. , Peters Zachary , Holtz Andrew , Haney Robert A. , Spatafora Grace A.
Published: March 2021

In 2020, untreated dental caries, especially in the permanent dentition, ranked among the most prevalent infectious diseases worldwide, disproportionately impacting individuals of low socioeconomic status. Untreated caries can lead to systemic health problems and have been associated with extended school and work absences, inappropriate use of emergency departments, and an inability for military forces to deploy.
Investigation of Burkholderia cepacia Complex Methylomes via Single-Molecule, Real-Time Sequencing and Mutant Analysis
Authors: Mannweiler Olga , Pinto-Carbó Marta , Lardi Martina , Agnoli Kirsty , Eberl Leo
Published: March 2021

While the genome sequence determines an organism’s proteins, methylation of the nucleotides themselves can confer additional properties. In bacteria, MTs modify specific nucleotide motifs to allow discrimination of “self” from “nonself” DNA, e.g., from bacteriophages.
An Assessment of Siderophore Production, Mucoviscosity, and Mouse Infection Models for Defining the Virulence Spectrum of Hypervirulent Klebsiella pneumoniae
Authors: Russo Thomas A. , MacDonald Ulrike , Hassan Sidra , Camanzo Ellie , LeBreton Francois , Corey Brendan , McGann Patrick
Published: March 2021

The pathogenic potential of hvKp strains is primarily mediated by a large virulence plasmid. The minimal set of genes required for the full expression of the hypervirulent phenotype is undefined.
From Plants to Ants: Fungal Modification of Leaf Lipids for Nutrition and Communication in the Leaf-Cutter Ant Fungal Garden Ecosystem
Authors: Khadempour Lily , Kyle Jennifer E. , Webb-Robertson Bobbie-Jo M. , Nicora Carrie D. , Smith Francesca B. , Smith Richard D. , Lipton Mary S. , Currie Cameron R. , Baker Erin S. , Burnum-Johnson Kristin E.
Published: March 2021

In this work, we examined the role of lipids in the mutualism between leaf-cutter ants and fungus. These ants cut fresh leaf material, which they provide to their fungal cultivar, that converts energy and nutrients from the plants and provides it to the ants in specialized hyphal swellings called gongylidia.
Mid-ocean-ridge rhyolite (MORR) eruptions on the East Pacific Rise lack the fizz to pop
Authors: Portner Ryan A. , Dreyer Brian M. , Clague David A.
Published: March 2021

Eruptions on the Alarcon Rise segment of the northern East Pacific Rise (23.55°N, 108.42°W) at 2500–2200 m below sea level (mbsl) produced the most compositionally diverse volcanic suite found along the submarine mid-ocean-ridge (MOR) system, offering an opportunity to compare mafic through silicic eruption styles at the same abyssal depth. Eruption styles that formed evolved volcanic rocks on the submarine MOR have not been studied in detail. The prevalence of lava flows along the MOR indicates that most eruptions are nonexplosive, but some volcaniclastic characteristics suggest that explosive styles also occur. Higher viscosities in intermediate (103–5 Pa·s) versus mafic (101 Pa·s) lavas on Alarcon Rise correspond with larger, more brecciated pillows, while highly viscous rhyolite lavas (106–7 Pa·s) formed rugged domes mostly composed of autoclastic breccia. Although high H2O contents (1.5–2.1 wt%), abundant volcaniclasts, and vesicularities up to 53% in rhyolite might imply eruption explosivity, limited fine-grained ash production and dispersal indicate an effusive origin. Higher viscosities of MOR rhyolite (MORR) magma and small eruption volumes, compared to MOR basalt (MORB), limit bubble coalescence and rapid magma ascent, two likely prerequisites for deep-marine eruption explosivity. This idea is supported by widespread dispersal of basaltic ash, but very limited production and dispersal of silicic ash on Alarcon Rise.
Cyclophosphates, a new class of native phosphorus compounds, and some insights into prebiotic phosphorylation on early Earth
Authors: Britvin Sergey N. , Murashko Michail N. , Vapnik Yevgeny , Vlasenko Natalia S. , Krzhizhanovskaya Maria G. , Vereshchagin Oleg S. , Bocharov Vladimir N. , Lozhkin Maksim S.
Published: March 2021

Cyclophosphates are a class of energy-rich compounds whose hydrolytic decomposition (ring opening) liberates energy that is sufficient for initiation of biomimetic phosphorylation reactions. Because of that, cyclophosphates might be considered as a likely source of reactive prebiotic phosphorus on early Earth. A major obstacle toward adoption of this hypothesis is that cyclophosphates have so far not been encountered in nature. We herein report on the discovery of these minerals in the terrestrial environment, at the Dead Sea basin in Israel. Cyclophosphates represent the most condensed phosphate species known in nature. A pathway for cyclophosphate geosynthesis is herein proposed, involving simple pyrolytic oxidation of terrestrial phosphides. Discovery of natural cyclophosphates opens new opportunities for modeling prebiotic phosphorylation reactions that resulted in the emergence of primordial life on our planet.
Supplemental Material: A metasedimentary source of gold in Archean orogenic gold deposits
Authors: Pitcairn Iain , al. et
Published: March 2021

Compositions of metasedimentary samples, and Table S2 (geochemical compositions of Pontiac, Porcupine and Cadillac samples collected in this study including sample locations, grid references and metamorphic facies grouping; black shale database including Au, As, and Sb data and sample name; and Mann-Whitney U-test results).
Employing learning health system principles to advance research on severe neonatal and paediatric illness in Kenya
Authors: English Mike , Irimu Grace , Akech Samuel , Aluvaala Jalemba , Ogero Morris , Isaaka Lynda , Malla Lucas , Tuti Timothy , Gathara David , Oliwa Jacquie , Agweyu Ambrose
Published: March 2021

We have worked to develop a Clinical Information Network (CIN) in Kenya as an early form of learning health systems (LHS) focused on paediatric and neonatal care that now spans 22 hospitals. CIN’s aim was to examine important outcomes of hospitalisation at scale, identify and ultimately solve practical problems of service delivery, drive improvements in quality and test interventions. By including multiple routine settings in research, we aimed to promote generalisability of findings and demonstrate potential efficiencies derived from LHS. We illustrate the nature and range of research CIN has supported over the past 7 years as a form of LHS. Clinically, this has largely focused on common, serious paediatric illnesses such as pneumonia, malaria and diarrhoea with dehydration with recent extensions to neonatal illnesses. CIN also enables examination of the quality of care, for example that provided to children with severe malnutrition and the challenges encountered in routine settings in adopting simple technologies (pulse oximetry) and more advanced diagnostics (eg, Xpert MTB/RIF). Although regular feedback to hospitals has been associated with some improvements in quality data continue to highlight system challenges that undermine provision of basic, quality care (eg, poor access to blood glucose testing and routine microbiology). These challenges include those associated with increased mortality risk (eg, delays in blood transfusion). Using the same data the CIN platform has enabled conduct of randomised trials and supports malaria vaccine and most recently COVID-19 surveillance. Employing LHS principles has meant engaging front-line workers, clinical managers and national stakeholders throughout. Our experience suggests LHS can be developed in low and middle-income countries that efficiently enable contextually appropriate research and contribute to strengthening of health services and research systems.
Non-invasive early exclusion of chronic thromboembolic pulmonary hypertension after acute pulmonary embolism: the InShape II study
Authors: Boon Gudula J A M , Ende-Verhaar Yvonne M , Bavalia Roisin , El Bouazzaoui Lahassan H , Delcroix Marion , Dzikowska-Diduch Olga , Huisman Menno V , Kurnicka Katarzyna , Mairuhu Albert T A , Middeldorp Saskia , Pruszczyk Piotr , Ruigrok Dieuwertje , Verhamme Peter , Vliegen Hubert W , Vonk Noordegraaf Anton , Vriend Joris W J , Klok Frederikus A
Published: March 2021

Background

The current diagnostic delay of chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary embolism (PE) is unacceptably long, causing loss of quality-adjusted life years and excess mortality. Validated screening strategies for early CTEPH diagnosis are lacking. Echocardiographic screening among all PE survivors is associated with overdiagnosis and cost-ineffectiveness. We aimed to validate a simple screening strategy for excluding CTEPH early after acute PE, limiting the number of performed echocardiograms.

Methods

In this prospective, international, multicentre management study, consecutive patients were managed according to a screening algorithm starting 3 months after acute PE to determine whether echocardiographic evaluation of pulmonary hypertension (PH) was indicated. If the ‘CTEPH prediction score’ indicated high pretest probability or matching symptoms were present, the ‘CTEPH rule-out criteria’ were applied, consisting of ECG reading and N-terminalpro-brain natriuretic peptide. Only if these results could not rule out possible PH, the patients were referred for echocardiography.

Results

424 patients were included. Based on the algorithm, CTEPH was considered absent in 343 (81%) patients, leaving 81 patients (19%) referred for echocardiography. During 2-year follow-up, one patient in whom echocardiography was deemed unnecessary by the algorithm was diagnosed with CTEPH, reflecting an algorithm failure rate of 0.29% (95% CI 0% to 1.6%). Overall CTEPH incidence was 3.1% (13/424), of whom 10 patients were diagnosed within 4 months after the PE presentation.

Conclusions

The InShape II algorithm accurately excluded CTEPH, without the need for echocardiography in the overall majority of patients. CTEPH was identified early after acute PE, resulting in a substantially shorter diagnostic delay than in current practice.
Fig development in two Neotropical Ficus species, Ficus (subg. Pharmacosycea) yoponensis and Ficus (subg. Spherosuke) colubrinae: comparing rainforest and pasture trees
Authors: Cervantes-Pasqualli Juan Alberto , Laborde Javier
Published: March 2021

In the fragmented landscape of Los Tuxtlas, adult fig trees are found in both rainforest remnants and in pastures. Syconium (fig) development is known to vary between and within Ficus species, but it is not known whether it differs between rainforest and pasture trees. Here, we describe syconium development for two Ficus species with different life forms (free-standing and hemi-epiphytic) in two contrasting, adjacent habitats: an undisturbed rainforest and active pastures. Over three months, we monitored 15 reproductive events in Ficus (subg. Pharmacosycea) yoponensis Desv. and Ficus (subg. Spherosuke) colubrinae Standl., collecting and dissecting syconia every 3–4 days (1291 and 815 syconia per species, respectively). External and internal structural changes in the syconia are described, including foundress occurrence and the maximum duration of the receptive phase while waiting for pollinators. The duration of both the reproductive events (<8 weeks) and the developmental phases in the two species did not differ between rainforest and pasture trees and are within the lower range of time reported for other Ficus species. After pollinator exclusion, the receptive phase lasted up to four times its normal duration. Syconia were slightly larger in rainforest trees than in pasture trees, and the infestation of F. yoponensis syconia by non-pollinating insects was higher in rainforest trees.
Estimation of conservation unit and population contribution to Chinook salmon mixed-stock fisheries in British Columbia, Canada, using direct DNA sequencing for single nucleotide polymorphisms
Authors: Beacham Terry D. , Wallace Colin , Jonsen Kim , Sutherland Ben J.G. , Gummer Carrie , Rondeau Eric B.
Published: March 2021

Determination of population structure and stock identification is a general problem in fisheries assessment and management. Pacific salmon fishery management regimes are evolving to require higher resolution of stock composition on increasingly smaller reporting units. For Chinook salmon (Oncorhynchus tshawytscha), a stock identification baseline comprised of some 125 198 individuals from 369 populations ranging from Russia to California was employed for genetic stock identification (GSI). GSI analysis based on variation at up to 547 single nucleotide polymorphisms (SNPs) was demonstrated to provide accurate estimates of stock composition for 68 conservation units (CUs) in British Columbia, 23 reporting groups in the United States, and one reporting group in Russia. In many instances, accurate population-specific estimates of stock composition within a CU were possible in fishery samples, as well as identifying individuals to some specific populations. A genetics-based assessment system provides an opportunity for conservation-based management of Canadian Chinook salmon.
Clubroot resistance in canola and brassica vegetable cultivars in Ontario, Canada
Authors: Drury Sarah C. , Gossen Bruce D. , McDonald Mary Ruth
Published: March 2021

Clubroot, caused by the obligate pathogen Plasmodiophora brassicae Woronin, has been present on brassica vegetables in Ontario for decades, but was only recently identified on canola (Brassica napus L.). Once P. brassicae is present in a field, eradication is difficult, but resistant cultivars can provide effective management. Pathotype 6 has been the predominant pathotype on vegetable crops for decades, but pathotype 2 is predominant in canola fields in Ontario. Field trials were used to assess the reaction of selected canola and vegetable Brassica cultivars to pathotype 2, and controlled environment studies were conducted to evaluate the reaction of the same cultivars to pathotypes 2 and 6. Four canola cultivars with putative clubroot resistance were compared with two cultivars that were expected to be susceptible and three susceptible control cultivars. Several brassica vegetables were assessed: cabbage, cauliflower, broccoli, napa cabbage, rutabaga, and Shanghai pak choi (a susceptible control). The canola cultivars marketed as resistant were highly resistant in both the field and growth room trials. The canola cultivars not marketed as resistant were susceptible to pathotype 2, as expected. All of the canola cultivars were resistant to pathotype 6. The vegetable cultivars marketed as resistant or tolerant were resistant to pathotype 6 and most were resistant to pathotype 2. A putative resistant cultivar of cabbage and one of broccoli were resistant to pathotype 6 but susceptible to pathotype 2. Clubroot consistently reduced fresh shoot weight in susceptible cultivars of canola and brassica vegetables relative to resistant cultivars.
Stokesian dynamics simulations of a magnetotactic bacterium
Authors: Mohammadinejad Sarah , Faivre Damien , Klumpp Stefan
Published: March 2021

The swimming of bacteria provides insight into propulsion and steering under the conditions of low-Reynolds number hydrodynamics. Here we address the magnetically steered swimming of magnetotactic bacteria. We use Stokesian dynamics simulations to study the swimming of single-flagellated magnetotactic bacteria (MTB) in an external magnetic field. Our model MTB consists of a spherical cell body equipped with a magnetic dipole moment and a helical flagellum rotated by a rotary motor. The elasticity of the flagellum as well as magnetic and hydrodynamic interactions is taken into account in this model. We characterized how the swimming velocity is dependent on parameters of the model. We then studied the U-turn motion after a field reversal and found two regimes for weak and strong fields and, correspondingly, two characteristic time scales. In the two regimes, the U-turn time is dominated by the turning of the cell body and its magnetic moment or the turning of the flagellum, respectively. In the regime for weak fields, where turning is dominated by the magnetic relaxation, the U-turn time is approximately in agreement with a theoretical model based on torque balance. In the strong-field regime, strong deformations of the flagellum are observed. We further simulated the swimming of a bacterium with a magnetic moment that is inclined relative to the flagellar axis. This scenario leads to intriguing double helical trajectories that we characterize as functions of the magnetic moment inclination and the magnetic field. For small inclination angles ($$\lesssim {20^{\circ }}$$

≲

20
∘

) and typical field strengths, the inclination of the magnetic moment has only a minor effect on the swimming of MTB in an external magnetic field. Large inclination angles result in a strong reduction in the velocity in direction of the magnetic field, consistent with recent observations that bacteria with large inclination angles use a different propulsion mechanism.

Graphic abstract
Quantum E(2) groups for complex deformation parameters
Authors: Rahaman Atibur , Roy Sutanu
Published: March 2021

We construct a family of [Formula: see text] deformations of [Formula: see text] group for nonzero complex parameters [Formula: see text] as locally compact braided quantum groups over the circle group [Formula: see text] viewed as a quasitriangular quantum group with respect to the unitary [Formula: see text]-matrix [Formula: see text] for all [Formula: see text]. For real [Formula: see text], the deformation coincides with Woronowicz’s [Formula: see text] groups. As an application, we study the braided analogue of the contraction procedure between [Formula: see text] and [Formula: see text] groups in the spirit of Woronowicz’s quantum analogue of the classic Inönü–Wigner group contraction. Consequently, we obtain the bosonization of braided [Formula: see text] groups by contracting [Formula: see text] groups.
Antecedents of Equity Fund Performance: A Contingency Perspective
Authors: Liu Li Xian , Jiang Fuming , Li Jizhong , Farooque Omar Al
Published: March 2021

While the fund performance management literature has clearly documented that the fund size, fund family size, and net cash flow are important antecedents of equity fund performance, prior empirical studies have revealed mixed results that have not been adequately explained. Through the lens of the contingency perspective, we developed a conceptual model that examines how the expense ratio and management compensation as contextual factors interact with the fund size, fund family size, and net cash flow to affect equity fund performance. The empirical analyses were based on panel data including 690 equity funds in China over a 7-year period from 2009 to 2015. The results show that the expense ratio and management compensation moderate the effects of the fund family size and net cash flow on fund performance, and management compensation also moderates the relationship between the fund size and fund performance.
Dynamics of a stochastic delayed avian influenza model with mutation and temporary immunity
Authors: Kang Ting , Zhang Qimin
Published: March 2021

In this paper, the dynamic behaviors are studied for a stochastic delayed avian influenza model with mutation and temporary immunity. First, we prove the existence and uniqueness of the global positive solution for the stochastic model. Second, we give two different thresholds [Formula: see text] and [Formula: see text], and further establish the sufficient conditions of extinction and persistence in the mean for the avian-only subsystem and avian-human system, respectively. Compared with the corresponding deterministic model, the thresholds affected by the white noises are smaller than the ones of the deterministic system. Finally, numerical simulations are carried out to support our theoretical results. It is concluded that the vaccination immunity period can suppress the spread of avian influenza during poultry and human populations, while prompt the spread of mutant avian influenza in human population.
Real-time Approximation of Photometric Polygonal Lights
Authors: Luksch Christian , Prost Lukas , Wimmer Michael
Published: March 2021

We present a real-time rendering technique for photometric polygonal lights. Our method uses a numerical integration technique based on a triangulation to calculate noise-free diffuse shading. We include a dynamic point in the triangulation that provides a continuous near-field illumination resembling the shape of the light emitter and its characteristics. We evaluate the accuracy of our approach with a diverse selection of photometric measurement data sets in a comprehensive benchmark framework. Furthermore, we provide an extension for specular reflection on surfaces with arbitrary roughness that facilitates the use of existing real-time shading techniques. Our technique is easy to integrate into real-time rendering systems and extends the range of possible applications with photometric area lights.
A Time-independent Deformer for Elastic-rigid Contacts
Authors: Brunel Camille , Bénard Pierre , Guennebaud Gaël , Barla Pascal
Published: March 2021

We introduce a new tool that assists artists in deforming an elastic object when it comes in intersection with a rigid one. As opposed to methods that rely on time-resolved simulations, our approach is entirely based on time-independent geometric operators. It thus restarts from scratch at every frame from a pair of objects in intersection and works in two stages: the intersected regions are first matched and a contact region is identified on the rigid object; the elastic object is then deformed to match the contact while producing plausible bulge effects with controllable volume preservation. Our direct deformation approach brings several advantages to 3D animators: it provides instant feedback, permits non-linear editing, allows for the replicability of the deformation in different settings, and grants control over exaggerated or stylized bulging effects.
Real-Time Stochastic Lightcuts
Authors: Lin Daqi , Yuksel Cem
Published: March 2021

We present real-time stochastic lightcuts, a real-time rendering method for scenes with many dynamic lights. Our method is the GPU extension of stochastic lightcuts [Yuksel 2019], a state-of-art hierarchical light sampling algorithm for offline rendering. To support arbitrary dynamic scenes, we introduce an extremely fast light tree builder. To maximize the performance of light sampling on the GPU, we introduce cut sharing, a way to reuse adaptive sampling information in light trees in neighboring pixels.