bluuebunny/crossref_metadata_2025 huggingface dataset:
Hydrogen isotopic exchange kinetics between organic matter and water: Implications for chemical evolution during meteorite parent body processing
Authors: Kebukawa Yoko , Kobayashi Sachio , Kawasaki Noriyuki , Wang Ying , Yurimoto Hisayoshi , Cody George D.
Published: March 2021

The large variations in hydrogen isotope ratios found in insoluble organic matter (IOM) in chondritic meteorites may be attributed to hydrogen isotopic exchange between IOM and water during aqueous alteration. We conducted D–H exchange experiments (1) during synthesis of IOM simulant (hereafter called chondritic organic analog, COA) from formaldehyde, glycolaldehyde, and ammonia with water, and (2) with the synthesized COA with a secondary reservoir of water. The changes in the D/H ratios obtained by infrared spectra of the COA suggest that most of the hydrogen in the COA is derived from water during synthesis. We further investigated the kinetics of D–H exchange between D‐rich COA and D‐poor water, as well as the opposite case, D‐poor COA and D‐rich water. To help assess understanding exchange kinetics, two‐dimensional isotope imaging obtained using isotope microscope revealed that no gradient D–H exchange profiles were present in the COA grains, indicating that the rate‐limiting step for D–H exchange is not diffusion. Thus, the changes in D/(D + H) ratios were fit by the first‐order reaction rate law. Apparent kinetic parameters—the rate constants, the activation energies, and the frequency factors—were obtained with the Arrhenius equation. Using these kinetic expressions, hydrogen isotopic exchange profiles were estimated for time and temperature behavior. The D–H exchange between organic matter and water is apparently relatively fast and this implies that the aqueous alteration temperatures should have been very low, likely close to 0 °C to maintain hydrogen isotopic disequilibrium between organic matter and liquid water for millions of years.
Dyadic explanations during preparatory self‐study enhance learning: A randomised controlled study
Authors: Rotgans Jerome I. , Cleland Jennifer A.
Published: March 2021

Objectives

The objective of the present study was to investigate to which extent preparatory self‐study can be improved by encouraging students to engage in individual self‐explanations or dyadic explanations (ie in pairs). Individual self‐explanations refer to an act of metacognition in which students, after having processed a certain amount of information, attempt to explain their understanding to themselves of what was just learned. Dyadic explanations refer to the same process, but instead of explaining to oneself, the student explains his/her understanding to another student.

Method

An experiment was conducted in which 120 medical students studied a video‐recorded lecture on the role of protein synthesis inhibition on memory reconsolidation. Participants were randomly allocated to one of four conditions: (1) a control condition in which they listened to the lecture once; (2) a control condition in which they listened to the lecture twice; (3) an experimental condition in which they had to listen to the lecture and provide self‐explanations individually; and (4) an experimental condition in which they had to listen to the lecture and provide dyadic explanations. Participants’ knowledge regarding the topic was measured three times: at the start and end of the experiment, and one week after the experiment to determine knowledge retention. Data were analysed by means of a 2 × 2 and 4 × 3 repeated‐measures ANOVA.

Results

The results suggest that participants who engaged in individual self‐ or dyadic explanations significantly outperformed participants in the two control conditions in terms of learning and retention (F = 5.67, Wilks Λ = 0.94, P = .019, η2 = 0.05). Moreover, the results suggest that dyadic explanations were more effective than individual self‐explanations (F = 3.70, Wilks Λ = 0.83, P = .002, η2 = 0.09).

Conclusions

These outcomes suggest that encouraging students to work in pairs or in small teams to prepare for a learning event results in superior preparation and learning.
Direct phosphorylation of HY5 by SPA kinases to regulate photomorphogenesis in Arabidopsis
Authors: Wang Wenli , Paik Inyup , Kim Junghyun , Hou Xilin , Sung Sibum , Huq Enamul
Published: March 2021

Elongated hypocotyl5 (HY5) is a key transcription factor that promotes photomorphogenesis. Constitutive photomorphogenic1 (COP1)–Suppressor of phytochrome A‐105 (SPA) E3 ubiquitin ligase complex promotes ubiquitination and degradation of HY5 to repress photomorphogenesis in darkness. HY5 is also regulated by phosphorylation at serine 36 residue. However, the kinase responsible for phosphorylation of HY5 remains unknown.

Here, using extensive in vitro and in vivo biochemical, genetic, and photobiological techniques, we have identified a new kinase that phosphorylates HY5 and demonstrated the significance of phosphorylation of HY5 in Arabidopsis thaliana.

We show that SPA proteins are the missing kinases necessary for HY5 phosphorylation. SPAs can directly phosphorylate HY5 in vitro, and the phosphorylated HY5 is absent in the spaQ background in vivo. We also demonstrate that the unphosphorylated HY5 interacts strongly with both COP1 and SPA1 and is the preferred substrate for degradation, whereas the phosphorylated HY5 is more stable in the dark. In addition, the unphosphorylated HY5 actively binds to the target promoters and is the physiologically more active form. Consistently, the transgenic plants expressing the unphosphorylated form of HY5 display enhanced photomorphogenesis.

Collectively, our study revealed the missing kinase responsible for direct phosphorylation of HY5 that fine‐tunes its stability and activity to regulate photomorphogenesis.
Ligament of Marshall ablation for persistent atrial fibrillation
Authors: Vlachos Konstantinos , Derval Nicolas , Pambrun Thomas , Duchateau Josselin , Martin Claire A. , Bazoukis George , Frontera Antonio , Takigawa Masateru , Nakashima Takashi , Efremidis Michael , Letsas Konstantinos P. , Bourier Felix , André Clémentine , Krisai Philipp , Ramirez F. Daniel , Kamakura Tsukasa , Takagi Takamitsu , Nakatani Yosuke , Tixier Romain , Chauvel Remi , Welte Nicolas , Kitamura Takeshi , Cheniti Ghassen , Sacher Frédéric , Jaïs Pierre , Haïssaguerre Michel , Hocini Mélèze
Published: March 2021

Beyond pulmonary vein isolation, the two main additional strategies: Cox‐Maze procedure or targeting of electrical signatures (focal bursts, rotational activities, meandering wavelets), remain controversial. High‐density mapping of these arrhythmias has demonstrated firstly that a patchy lesion set is highly proarrhythmogenic, favoring macro‐re‐entry through conduction slowing and providing pivots for localized re‐entry. Secondly, discrete anatomical structures such as the Vein or Ligament of Marshall (VOM/LOM) and the coronary sinus (CS) have epicardial muscular bundles that are more frequently involved in re‐entry than previously thought. The Marshall Bundle can be ablated at any point along its course from the mid‐to‐distal coronary sinus to the left atrial appendage. If necessary, the VOM may be directly ablated using ethanol infusion to eliminate PV contributions and produce conduction block across the mistral isthmus. Ethanol ablation of the VOM, supplemented with RF ablation, may be more effective in producing conduction block at the mitral isthmus than repeat RF ablation alone.
Inducibility of atrial fibrillation after catheter ablation predicts recurrences of atrial fibrillation: a meta‐analysis
Authors: Millenaar Dominic , Becker Nicolas , Pavlicek Valérie , Wintrich Jan , Böhm Michael , Mahfoud Felix , Ukena Christian
Published: March 2021

Background

Pulmonary vein isolation (PVI) is a component of standard care for patients with symptomatic atrial fibrillation (AF). Procedural inducibility of AF following PVI has been suggested as predictor of AF recurrence but is discussed controversially. This meta‐analysis aimed at evaluating the relevance of electrophysiological inducibility of AF following PVI for future AF recurrences.

Methods

A literature search of MEDLINE and Web of Science was performed until April 2020. Prospective trials of PVI in patients with AF and post‐procedural atrial stimulation to test for inducibility of AF as well as adequate follow‐up for AF recurrence (defined as AF >10 s to >10 min at follow‐up) were included. Odds ratios (ORs) were analyzed using random‐effects models.

Results

A total of 11 trials with 1544 patients (follow‐up 7–39 months, age 56 ± 6 years, predominantly male 74 ± 6%) were included. Inducibility of AF post‐PVI was predictive for AF recurrence during follow‐up (OR 2.08; 95% CI 1.25 to 3.46). Prediction for AF recurrence at follow‐up was better for patients with paroxysmal AF (OR 4.06; 95% CI 1.39 to 11.91), stimulation in the CS (OR 2.82, 95% CI 1.17 to 6.79). A trend towards higher ORs was seen without the use of isoproterenol (OR 2.43; 95% CI 1.17 to 5.07), as well as few stimulations during induction and a short definition of AF in meta‐regression analyses.

Conclusions

Electrophysiological inducibility of AF following PVI was predictive for future recurrence of AF, in particular in patients with paroxysmal AF, stimulation in only CS and no use of isoproterenol.
Rapid systemic uptake of naloxone after intranasal administration in children
Authors: Malmros Olsson Eva , Lönnqvist Per‐Arne , Stiller Carl‐Olav , Eksborg Staffan , Lundeberg Stefan
Published: March 2021

Background

Naloxone has a high affinity for the µ‐opioid receptor and acts as a competitive antagonist, thus reversing the effects of opioids. Naloxone is often administrated intravenously, but there is a growing interest in the intranasal route in treating patients with opioid overdose, and in reversing effects after therapeutic use of opioids. As administration is painless and no intravenous access is needed, the intranasal route is especially useful in children.

Aim

The aim of this study was to investigate the uptake of naloxone 0.4 mg/ml during the first 20 min after administration as a nasal spray in a pediatric population, with special focus on the time to achieve maximum plasma concentration.

Methods

Twenty children, 6 months–10 years, were included in the study. The naloxone dose administered was 20 µg/kg, maximum 0.4 mg, divided into repeated doses of 0.1 ml in each nostril. Venous blood samples were collected at 5, 10, and 20 min after the end of administration.

Results

All patients had quantifiable concentrations of naloxone in venous blood at 5 min, and within 20 min, peak concentration had been reached in more than half of the children. At 20 min after intranasal administration, the plasma naloxone concentrations were within the range of 2–6 nanogram/ml.

Conclusion

This study confirms the clinical experience that the rapid effect of naloxone after intranasal administration in children was reflected in rapid systemic uptake to achieve higher peak plasma concentrations than previously reported in adults.
Learning Facts About Migration: Politically Motivated Learning of Polarizing Information About Refugees
Authors: Glinitzer Konstantin , Gummer Tobias , Wagner Markus
Published: March 2021

Information processing during heated debates on asylum and immigration may often be influenced by prejudice rather than a desire to learn facts. In this article, we investigate how people process empirical evidence on the consequences of refugee arrivals through a novel survey experiment that disentangles politically motivated learning from other forms of learning and expressive responding. Specifically, we ask respondents to interpret a 2×2 table about the relationship between asylum seekers and crime rates. Crucially, respondents are randomly allocated to evaluate a conclusion that triggers their identity‐protective stakes or not. In addition, we test for motivated responding as an alternative explanation by randomly providing some respondents with a response format that motivates them to report their inference truthfully. We find that information processing changes substantially when new information challenges existing asylum attitudes. Politically motivated learning is strongest among voters with strong negative prior attitudes towards asylum seekers. Our results also indicate that expressive responding can only partially account for this gap in correctly reported inferences. Our research has important implications for research on the consequences of refugee migration, theories of motivated reasoning, and survey methodology.
Scrutinizing the impact of water deficit in plants: Transcriptional regulation, signaling, photosynthetic efficacy, and management
Authors: Kaur Harsimran , Kohli Sukhmeen Kaur , Khanna Kanika , Bhardwaj Renu
Published: March 2021

Suboptimal availability of water limits plant growth, development, and performance. Drought is one of the leading factors responsible for worldwide crop yield reduction. In the future, owing to climate changes, more agricultural land will be affected by prolonged periods of water deficit. Thus, understanding the fundamental mechanism of drought response is a major scientific concern for improvement of crop production. To combat drought stress, plants deploy varied mechanistic strategies and alter their morphological, physiochemical, and molecular attributes. This helps plant to enhance water uptake and storage, reduce water loss and avoid wilting. Induction of several transcription factors and drought responsive genes leads to synthesis of stress proteins, regulation of water channels i.e. aquaporins and production of osmolytes that are essential for maintenance of osmotic balance at the cellular level. Self‐ and hormone‐regulated signaling pathways are often stimulated by plants after receiving drought stress signals via secondary messengers, mitogen‐activated protein kinases, and stress hormones. These signaling cascades often leads to stomatal closure and reduction in transpiration rates. Reduced carbon dioxide diffusion in chloroplast, lowered efficacy of photosystems, and other metabolic constraints limits the key regulatory photosynthetic process during water deficit. The impact of these stomatal and nonstomatal limitations varies with stress intensity, superimposed stresses and plant species. A clear understanding of the drought resistance process is thus important before adopting strategies for imparting drought tolerance in plants. These management practices at present include exogenous hormone application, breeding, and genetic engineering techniques for combating the water deficit issues.
Exploiting the Capabilities of Bayesian Networks for Engineering Risk Assessment: Causal Reasoning through Interventions
Authors: Ruiz‐Tagle Andres , Lopez Droguett Enrique , Groth Katrina M.
Published: March 2021

In the last decade, Bayesian networks (BNs) have been widely used in engineering risk assessment due to the benefits that they provide over other methods. Among these, the most significant is the ability to model systems, causal factors, and their dependencies in a probabilistic manner. This capability has enabled the community to do causal reasoning throughassociations, which answers questions such as: “How does new evidence about the occurrence of event change my belief about the occurrence of event ?” Associative reasoning has helped risk analysts to identify relevant risk‐contributing factors and perform scenario analysis by evidence propagation. However, engineering risk assessment has yet to explore other features of BNs, such as the ability to reason throughinterventions, which enables the BN model to support answering questions of the form “How doesdoingchange my belief about the occurrence of event ?” In this article, we propose to expand the scope of use of BN models in engineering risk assessment to support intervention reasoning. This will provide more robust risk‐informed decision support by enabling the modeling of policies and actions before being implemented. To do this, we provide the formal mathematical background and tools to model interventions in BNs and propose a framework that enables its use in engineering risk assessment. This is demonstrated in an illustrative case study on third‐party damage of natural gas pipelines, showing how BNs can be used to inform decision‐makers about the effect that new actions/policies can have on a system.
Bending of Curved Thin Tubes
Authors: Beskin Leon
Published: March 2021

The stress distribution in curved tubes under the action of applied couples acting either in the plane of curvature of the tube or perpendicularly to that plane greatly differs from the conventional beam distribution, especially in the case of tubes with thin walls and a great curvature of the center line. For that reason, curved tubes with thin walls are much more flexible under applied couples than the corresponding straight tubes. The stress distribution in curved tubes, and its influence on the rigidity, are examined by the author in the case when the ratio of the radius of the center line to the radius of the tube is great. It is also shown that, when this ratio is small, the results relative to rigidity remain fairly accurate, while the results relative to stress distribution are incorrect and require a more complete analysis.
The Structural Efficiency of Wing Covers
Authors: Donovan A. F. , Goland Martin , Goodier J. N.
Published: March 2021

The paper seeks to establish rational criteria for evaluating the structural efficiencies of sheet-stiffener combinations and alternative constructions used for wing and other surfaces, and to determine the suitability of the available materials for panels of various proportions. The efficiency criteria require the determination of the ideal construction for such panels, and this is carried out. It is found that the primary requirement of the “best” material for the ideal design is a high strength-weight ratio (yield stress-density). A diagram (Fig. 5) is given to determine readily the weights of panels of ideal design made of various materials, all to carry the same load. In general one material is better than another only for a limited range of panel proportions.
Measurement of Torque Transmitted by Rotating Shafts
Authors: Langer B. F.
Published: March 2021

Various torque-measuring devices are described briefly and a more detailed description is given of the recently developed “magnetic-coupled” torquemeter. This new-device operates on a rotating shaft without brushes or slip rings and is particularly applicable where high speeds and severe operating conditions are encountered.
The Axial Vibration of Turbine Disks
Authors: Moody A. M. G.
Published: March 2021

The theoretical basis for calculation of disk vibrations developed by Stodola leaves a wide gap to be supplied between theory and useful procedure. This paper outlines a method by which the designer may obtain useful results without resorting to complicated procedures and with a minimum of empirical modifications. Taking Stodola’s differential equations for the energy of an element of a disk, including bending energy when disk is in its position of extreme deflection, kinetic energy as disk passes through its undeflected position, and work done against centrifugal force, the author presents a simplified method of applying them which results in a satisfactory degree of accuracy with but slight expenditure of time in calculations. He points out that static-frequency calculations make a convenient basis for comparing disks and may be checked much more readily experimentally than running frequencies, although the latter may at times be necessary if static-frequency results are too low. In a typical calculation for static frequency for a 3-nodal-diameter vibration of a steel disk, the procedure is demonstrated, and the use of tables of function for simplifying the work is indicated.
Fatigue Tests of Airplane Generator Brackets With Special Reference to Failure of Screw Fastenings
Authors: Wahl A. M.
Published: March 2021

Fatigue tests on forged-steel airplane-generator brackets of different proportions are described. It was found that in many cases the limiting factor in the strength of the assembly was not that of the bracket itself but rather that of the screw fastenings used to hold the bracket to the generator frame. The fatigue strength of these screw fastenings is largely dependent on the rigidity (or thickness) of the bracket rim, since a flexible rim allows a high variable stress to be set up. Methods, which appear to yield reasonable results for design purposes, are given for calculating screw stresses as well as spoke and rim stresses in brackets of this type.
Direct Analysis of Mechanical Wave Filters
Authors: Binder R. C.
Published: March 2021

Certain basic mechanical-filter sections are analyzed directly by means of the mobility method. Following the development of general relations is a discussion of low-, high-, and band-pass filters. Both filter structure and characteristics are treated.
Inelastic Buckling of Variable-Section Columns
Authors: Young Dana
Published: March 2021

A method is outlined for determining the critical load for variable-section columns in the inelastic range, that is, when the column is so short that buckling takes place after the stress at any section has exceeded the proportional limit of the material. The method is based on the Engesser-Considère theory and makes use of difference equations to solve the problem. The procedure is illustrated by a numerical example. The results of calculations for three different types of pin-ended columns are given.
A Graphic Resolution of Strain
Authors: Hoff N. J.
Published: March 2021

A purely graphic procedure is developed for the resolution of strain data obtained from measurements by strain rosettes of any shape. The characteristic features of the procedure arc: (a) The diagram is constructed directly from the measured data, without necessitating even addition; (b) strains are represented by distances measured in the true directions; (c) the true directions of principal strain are shown; (d) the true sense of rotation of straight lines is shown. The development of the procedure affords a purely geometric proof of the representation of the state of two-dimensional strain by Mohr’s circle.
Tension Tests at Constant True Strain Rates
Authors: MacGregor C. W. , Fisher J. C.
Published: March 2021

Tension tests of the true stress-strain type are reported for which the true strain rate is maintained constant throughout each test. Several metals are investigated under testing temperatures ranging from −183 C to 665 C. The influence of temperature and strain velocity on the true stress-strain properties is described. A single variable called the velocity-modified temperature is used to represent the combined influences of true strain rate and testing temperature.
Electric Turret-Traversing Mechanism for Tanks
Authors: Mikina Stanley J.
Published: March 2021

This paper describes the development of a new electric-power drive for 360-deg traverse of tank turrets that was undertaken early in 1941. The development was brought to a successful conclusion with the satisfactory completion of Army Ordnance acceptance tests on December 6, 1941, and mass production of these traverse units was achieved shortly after Pearl Harbor Day, in time to equip the General Sherman tanks that contributed to the victories in the North African campaigns. A description of the drive and its positionally regulated system of control is given together with the mathematical analysis of system stability upon which the design criteria of the control were based.
Parallel Columns With Common Lateral Supports
Authors: Langhaar H. L.
Published: March 2021

Problems in the stress analyses of semimonocoque aircraft structures have suggested the investigation of the stability of a system of closely spaced, equally stressed, parallel columns with lateral bulkhead supports. The theory presented in this paper establishes a correlation between this problem and the problem of stability of a single column with lateral spring supports. Since the theory for the latter case has been developed by several authors, the correlation effects a solution of the more general problem.
Modeling Noise Radiation From Concrete Box Girder Bridges as an Infinitely Long Periodic Structure Excited by a High-Speed Train
Authors: He Yuanpeng , Cheng Gong , Han Jian , Sheng Xiaozhen
Published: March 2021

Concrete box girder bridges occupy over 80% of the total mileage of the Chinese high-speed railway. The box girder structure has many natural modes of low frequencies, which can be excited by a train passing at high-speed, generating low-frequency bridge noise. This paper is concerned with the prediction of such bridge noise and reports a prediction model. The model, as other existing models of the same nature, also incorporates two parts, one dealing with vehicle–track-viaduct dynamics and the other dealing with sound radiation from the girders, but takes into account more features related to high-speed. In this model, vehicle–track-viaduct dynamics is dealt with in the frequency-domain based on the theory of infinitely long periodic structure and the Fourier-series method, predicting vibration frequency spectra for each and every box girder. The predicted vibration frequency spectra of all the box girders are expressed as a sum of propagating waves at different wavenumbers, and sound radiation from each propagating wave is evaluated using the 2.5D acoustic boundary element method. This approach to sound radiation enables contributions from all the box girders to be included at a reasonable computational cost. This paper continues with a comparison in bridge vibration and noise between prediction and measurement for a typical site. And finally, based on the parameters of that site, characteristics of noise radiation from the concrete box girders are studied using the prediction model.
The Plasmid-Mediated
Kluyvera
-Like
arnBCADTEF
Operon Confers Colistin (Hetero)Resistance to Escherichia coli
Authors: Gallardo Alejandro , Iglesias María-Rocío , Ugarte-Ruiz María , Hernández Marta , Miguela-Villoldo Pedro , Gutiérrez Gloria , Rodríguez-Lázaro David , Domínguez Lucas , Quesada Alberto
Published: March 2021

The use of colistin as a last-resort antimicrobial is compromised by the emergence of resistant enterobacteria with acquired determinants like
mcr
genes, mutations that activate the PmrAB system, and still unknown mechanisms. This work analyzed 74
Escherichia coli
isolates from healthy swine, turkey, or bovine, characterizing their colistin resistance determinants.
Emergence of Two AcrB Substitutions Conferring Multidrug Resistance to
Salmonella
spp.
Authors: Yang Ling , Shi Haiyang , Zhang Lijuan , Lin Xiaoling , Wei Yinan , Jiang Hongxia , Zeng Zhenling
Published: March 2021

AcrAB-TolC is a major tripartite multidrug efflux pump conferring resistance to a wide variety of compounds in Gram-negative pathogens. Many AcrB mutants have been constructed through site-directed mutagenesis to probe the mechanism of AcrB function in antibiotic resistance.
Protolith affiliation and tectonometamorphic evolution of the Gurla Mandhata core complex, NW Nepal Himalaya
Authors: Godin Laurent , Ahenda Mark , Grujic Djordje , Stevenson Ross , Cottle John
Published: March 2021

Assigning correct protolith to high metamorphic-grade core zone rocks of large hot orogens is a particularly important challenge to overcome when attempting to constrain the early stages of orogenic evolution and paleogeography of lithotectonic units from these orogens. The Gurla Mandhata core complex in NW Nepal exposes the Himalayan metamorphic core (HMC), a sequence of high metamorphic-grade gneiss, migmatite, and granite, in the hinterland of the Himalayan orogen. Sm-Nd isotopic analyses indicate that the HMC comprises Greater Himalayan sequence (GHS) and Lesser Himalayan sequence (LHS) rocks. Conventional interpretation of such provenance data would require the Main Central thrust (MCT) to be also outcropping within the core complex. However, new in situ U-Th/Pb monazite petrochronology coupled with petrographic, structural, and microstructural observations reveal that the core complex is composed solely of rocks in the hanging wall of the MCT. Rocks from the core complex record Eocene and late Oligocene to early Miocene monazite (re-)crystallization periods (monazite age peaks of 40 Ma, 25–19 Ma, and 19–16 Ma) overprinting pre-Himalayan Ordovician Bhimphedian metamorphism and magmatism (ca. 470 Ma). The combination of Sm-Nd isotopic analysis and U-Th/Pb monazite petrochronology demonstrates that both GHS and LHS protolith rocks were captured in the hanging wall of the MCT and experienced Cenozoic Himalayan metamorphism during south-directed extrusion. Monazite ages do not record metamorphism coeval with late Miocene extensional core complex exhumation, suggesting that peak metamorphism and generation of anatectic melt in the core complex had ceased prior to the onset of orogen-parallel hinterland extension at ca. 15–13 Ma. The geometry of the Gurla Mandhata core complex requires significant hinterland crustal thickening prior to 16 Ma, which is attributed to ductile HMC thickening and footwall accretion of LHS protolith associated with a Main Himalayan thrust ramp below the core complex. We demonstrate that isotopic signatures such as Sm-Nd should be used to characterize rock units and structures across the Himalaya only in conjunction with supporting petrochronological and structural data.
Acoustic neuroma presenting as a hypnic headache
Authors: Ceronie Bryan , Green Frederick , Cockerell Oliver Charles
Published: March 2021

Hypnic headache (HH) is a rare, primary headache syndrome that invariably occurs during sleep and wakes the patient. Acoustic neuroma (AN) is a benign tumour that uncommonly presents with isolated headache. Here, we describe a patient with AN that presented with an HH-like syndrome. A 40-year-old woman presented with 4 months of generalised, throbbing, nocturnal headaches that woke her from sleep. Neurological examination was unremarkable. Retrospectively, she reported a 4-year history of mild, bilateral tinnitus. Neuroimaging demonstrated a large, left-sided AN in the cerebellopontine angle without obstructive hydrocephalus. Gamma knife radiosurgery controlled tumour growth. One year after radiosurgery, she became nocturnal headache-free. AN has not previously been described as presenting with an HH-like syndrome. There are four previous reports of an HH-like syndrome secondary to intracranial masses. In all cases, patients became headache-free following surgery. This advocates for neuroimaging to exclude structural causes.
Imperforate hymen mimicking acute appendicitis in an adolescent woman: a rare presentation
Authors: Russell Victoria Rose , Ibrahim Mohamed , Phillips Georgina , Setchell Tom , Purkayastha Sanjay
Published: March 2021

Imperforate hymen is a rare congenital malformation of the female genital tract. The condition poses several diagnostic challenges owing to its low incidence and often atypical presentation. Classical symptoms include amenorrhoea and cyclical abdominal pain. Delayed diagnosis leads to potentially irreversible and lifechanging sequelae including infertility, endometriosis and renal failure. A premenarchal 13-year-old girl with a background of chronic constipation presented with symptoms mimicking acute appendicitis. The underlying cause was imperforate hymen and retrograde menstruation. The diagnosis was made during diagnostic laparoscopy. As with this patient, pre-existing symptoms are often troublesome long before the true diagnosis is made. This case report highlights the importance of recognising imperforate hymen as a potential cause of acute abdominal pain in premenarchal adolescent girls. The clinical picture may present as right or left iliac fossa pain. Early identification reduces the risk of adverse complications and avoids unnecessary and potentially harmful interventions.
Impact and effect mechanisms of mass campaigns in resource-constrained health systems: quasi-experimental evidence from polio eradication in Nigeria
Authors: Haenssgen Marco J , Closser Svea , Alonge Olakunle
Published: March 2021

Background

Mass campaigns are a key strategy for delivering life-saving interventions under Global Health Initiatives, especially in weak health system contexts. They are frequently designed parallel to the health system to rapidly achieve programme targets such as vaccination coverage, but we lack quantitative evidence demonstrating their impact and effect mechanisms on health system performance at sub-/national level. This longitudinal study responds to this gap through an analysis of polio eradication campaigns in Nigeria.

Methods

Using four rounds of Demographic and Health Surveys in Nigeria between October 2000 and December 2017, we created a longitudinal dataset containing 88 881 under-5 children/pregnancies. We estimated the relationships between individuals’ campaign exposure and health system performance indices (full RI schedule attainment, maternal healthcare services utilisation and child survival) using multilevel, mixed-effects regression models applied nationally and stratified by the six geopolitical zones in Nigeria.

Results

Nationally, high-frequency mass campaigns had detrimental health systems effects that potentially left 3.6 million children deprived of full immunisation. The frequency of campaigns was most concentrated in regions with weak health systems, where the operations of RI were disrupted, alongside negative effects on child survival and institutional delivery. In contrast, regions with relatively strong health systems and few campaigns experienced beneficial effects on maternal healthcare service utilisation.

Conclusions

As we provide evidence that well-functioning health systems can benefit from mass campaigns under Global Health Initiatives, our work also challenges the established wisdom to intensify mass campaigns in weaker health systems to bypass service provision bottlenecks. Mass campaigns do not inherently benefit or damage a health system, but frequent campaigns in weak health system contexts can impede service provision. We call for an additional burden of proof and active efforts to integrate mass campaigns into routine health services by harmonising implementation plans and service delivery in weak health system contexts.
How fragile are Mediterranean diet interventions? A research-on-research study of randomised controlled trials
Authors: Grammatikopoulou Maria G , Nigdelis Meletios P , Theodoridis Xenophon , Gkiouras Konstantinos , Tranidou Antigoni , Papamitsou Theodora , Bogdanos Dimitrios P , Goulis Dimitrios G
Published: March 2021

Introduction

The Mediterranean diet (MD) is a traditional regional dietary pattern and a healthy diet recommended for the primary and secondary prevention of various diseases and health conditions. Results from the higher level of primary evidence, namely randomised controlled trials (RCTs), are often used to produce dietary recommendations; however, the robustness of RCTs with MD interventions is unknown.

Methods

A systematic search was conducted and all MD RCTs with dichotomous primary outcomes were extracted from PubMed. The fragility (FI) and the reverse fragility index (RFI) were calculated for the trials with significant and non-significant comparisons, respectively.

Results

Out of 27 RCTs of parallel design, the majority failed to present a significant primary outcome, exhibiting an FI equal to 0. The median FI of the significant comparisons was 5, ranging between 1 and 39. More than half of the comparisons had an FI <5, indicating that the addition of 1–4 events to the treatment arm eliminated the statistical significance. For the comparisons with an FI=0, the RFI ranged between 1 and 29 (Median RFI: 7). When the included RCTs were stratified according to masking, the use of a composite primary endpoint, sample size, outcome category, or dietary adherence assessment method, no differences were exhibited in the FI and RFI between groups, except for the RFI among different compliance assessment methods.

Conclusions

In essence, the present study shows that even in the top tiers of evidence hierarchy, research on the MD may lack robustness, setting concerns for the formulation of nutrition recommendations.
Knowledge and attitudes of university health students in the Pacific Islands towards childhood hearing loss and hearing services: a Samoan survey study protocol
Authors: Kaspar Annette , Pifeleti Sione , Driscoll Carlie
Published: March 2021

Introduction

The Pacific Islands have among the highest rates of ear disease and hearing loss in the world, especially among children. Given that Ear, Nose and Throat (ENT)/audiology specialists are limited in the region, the successful implementation of ear and hearing health services will depend on the participation and support of the wider community of health professionals. There are currently no studies from the Pacific Islands investigating the knowledge and attitudes of either health students or health professionals towards childhood hearing loss and hearing services.

Methods and analysis

Survey of medical and nursing students (n=370) currently enrolled at the National University of Samoa. Students will independently and anonymously complete a 10-item questionnaire. The questions assess attitudes to childhood hearing loss (two questions), knowledge of aetiology of childhood hearing loss (three questions), and knowledge of identification and interventions for children with hearing loss (five questions). Responses are based on a 5-point Likert scale (Strongly agree/Agree/Neutral/Disagree/Strongly disagree).

Discussion/conclusion

We publish these protocols to facilitate similar studies in other low-income and middle-income countries, and especially among our Pacific Island neighbours.
Exploring activity levels in physical education lessons in the UK: a cross-sectional examination of activity types and fitness levels
Authors: Beale Nick , Eldridge Emma , Delextrat Anne , Esser Patrick , Bushnell Oliver , Curtis Emily , Wassenaar Thomas , Wheatley Catherine , Johansen-Berg Heidi , Dawes Helen
Published: March 2021

Objectives

To establish pupil fitness levels, and the relationship to global norms and physical education (PE) enjoyment. To measure and describe physical activity (PA) levels during secondary school PE lessons, in the context of recommended levels, and how levels vary with activity and lesson type.

Methods

A cross-sectional design; 10 697 pupils aged 12.5 (SD 0.30) years; pupils who completed a multistage fitness test and wore accelerometers to measure PA during PE lessons. Multilevel models estimated fitness and PE activity levels, accounting for school and class-level clustering.

Results

Cardiorespiratory fitness was higher in boys than girls (ß=−0.48; 95% CI −0.56 to −0.39, p<0.001), within absolute terms 51% of boys and 54% of girls above the 50th percentile of global norms. On average, pupils spent 23.8% of PE lessons in moderate-to-vigorous PA (MVPA), and 7.1% in vigorous PA (VPA). Fitness-focused lessons recorded most VPA in co-educational (ß=1.09; 95% CI 0.43 to 1.74) and boys-only lessons (ß=0.32; 95% CI −0.21 to 0.85). In girls-only lessons, track athletics recorded most VPA (ß=0.13; 95% CI −0.50 to 0.75) and net/wall/racket games (ß=0.97; 95% CI 0.12 to 1.82) the most MVPA. For all lesson types, field athletics was least active (ß=−0.85; 95% CI −1.33 to −0.36). There was a relationship of enjoyment of PE to fitness (ß=1.03; 95% CI 0.83 to 1.23), and this relationship did not vary with sex (ß=−0.14 to 0.23; 95% CI −0.16 to 0.60).

Conclusions

PE lessons were inactive compared with current guidelines. We propose that if we are to continue to develop a range of sporting skills in schools at the same time as increasing levels of fitness and PA, there is a need to introduce additional sessions of PE activity focused on increasing physical activity.

Trial registration number

NCT03286725.
Safety and activity of the TGFβ receptor I kinase inhibitor galunisertib plus the anti-PD-L1 antibody durvalumab in metastatic pancreatic cancer
Authors: Melisi Davide , Oh Do-Youn , Hollebecque Antoine , Calvo Emiliano , Varghese Anna , Borazanci Erkut , Macarulla Teresa , Merz Valeria , Zecchetto Camilla , Zhao Yumin , Gueorguieva Ivelina , Man Michael , Gandhi Leena , Estrem Shawn T , Benhadji Karim A , Lanasa Mark C , Avsar Emin , Guba Susan C , Garcia-Carbonero Rocio
Published: March 2021

Background

We assessed the safety, efficacy, and pharmacokinetics of the transforming growth factor beta (TGFβ) receptor inhibitor galunisertib co-administered with the anti-programmed death-ligand 1 (PD-L1) antibody durvalumab in recurrent/refractory metastatic pancreatic cancer previously treated with ≤2 systemic regimens.

Methods

This was a two-part, single-arm, multinational, phase Ib study. In a dose-finding phase, escalating oral doses of galunisertib were co-administered on days 1–14 with fixed-dose intravenous durvalumab 1500 mg on day 1 every 4 weeks (Q4W), followed by an expansion cohort phase.

Results

The galunisertib recommended phase II dose (RP2D) when co-administered with durvalumab 1500 mg Q4W was 150 mg two times per day. No dose-limiting toxicities were recorded. Among 32 patients treated with galunisertib RP2D, 1 patient had partial response, 7 had stable disease, 15 had objective progressive disease, and 9 were not evaluable. Disease control rate was 25.0%. Median overall survival and progression-free survival were 5.72 months (95% CI: 4.01 to 8.38) and 1.87 months (95% CI: 1.58 to 3.09), respectively. Pharmacokinetic profiles for combination therapy were comparable to those published for each drug. There was no association between potential biomarkers and treatment outcomes.

Conclusion

Galunisertib 150 mg two times per day co-administered with durvalumab 1500 mg Q4W was tolerable. Clinical activity was limited. Studying this combination in patients in an earlier line of treatment or selected for predictive biomarkers of TGFβ inhibition might be a more suitable approach.

Trial registration number

ClinicalTrials.gov identifier:NCT02734160.
A Robust Method for Dehazing of Single Image with Sky Region Detection and Segmentation
Authors: Pal Tannistha
Published: March 2021

In recent times, there has been a tremendous progress in image dehazing for computer vision applications, while the sky region processed by these algorithms tends to degrade by noise and color distortion. In this paper, an improved dark channel prior algorithm is proposed which detects the sky region first and divides the image into sky region and non-sky region and then estimates the transmission of two parts separately, followed by combining with refining step. The proposed algorithm also accurately corrects the transmission of the sky region to avoid noise and color distortion. Experimental results show a greater quality improvement in the output images than the existing strategies.
Single-Image Dehazing via Dark Channel Prior and Adaptive Threshold
Authors: Pan Yongpeng , Chen Zhenxue , Li Xianming , He Weikai
Published: March 2021

Due to the haze weather, the outdoor image quality is degraded, which reduces the image contrast, thereby reducing the efficiency of computer vision systems such as target recognition. There are two aspects of the traditional algorithm based on the principle of dark channel to be improved. First, the restored images obviously contain color distortion in the sky region. Second, the white regions in the scene easily affect the atmospheric light estimated. To solve the above problems, this paper proposes a single-image dehazing and image segmentation method via dark channel prior (DCP) and adaptive threshold. The sky region of hazing image is relatively bright, so sky region does not meet the DCP. The sky part is separated by the adaptive threshold, then the scenery and the sky area are dehazed, respectively. In order to avoid the interference caused by white objects to the estimation of atmospheric light, we estimate the value of atmospheric light using the separated area of the sky. The algorithm in this paper makes up for the shortcoming that the algorithm based on the DCP cannot effectively process the hazing image with sky region, avoiding the effect of white objects on estimating atmospheric light. Experimental results show the feasibility and effectiveness of the improved algorithm.
A Simulation Optimisation Approach for Managing Bed Capacity in an Intensive Care Unit
Authors: Mohamed Israa , Hussein Rania
Published: March 2021

Determining the optimal number of beds in a hospital unit is often a very critical task. Patients’ number of arrivals and length of stay are random variables which necessitates the treatment with the number of patients at hospital as a stochastic process, and thus adding to the complexity of the bed sizing problem. The optimal number of beds is affected by some critical parameters such as target utilisation level, admission rate and target service level. This study applies a discrete event simulation model to approximate the true relationships between different control parameters and optimal number of beds. A goal programming model is then solved to find the optimal number of beds that maintains minimal deviation from target admission and utilisation levels. Data have been collected for the calendar year 2019 and then analysed and used in the simulation model. Mathematical relationships are then embedded in a multiobjective optimisation model that finds the optimal number of beds in an Intensive Care Unit that minimises the deviations from a pre-specified service and beds utilisation levels.
WHAT INFLUENCES US TO SUPPORT A CROWDFUNDING PROJECT? A FACTORIAL SURVEY ANALYSIS TO VALIDATE AND EXTEND EXISTING KNOWLEDGE
Authors: MOYSIDOU KRYSTALLIA
Published: March 2021

There is abundant research on the factors that influence backers’ decision to support a crowdfunding project. Yet work validating existing results and offering in a single study a direct comparison of those factors among crowdfunding types is needed. We draw upon the theory of perceived values and examine empirically which perceived values influence backers’ decision across equity, lending and reward-based crowdfunding. We employ a factorial survey that testes how changing the type of crowdfunding (ceteris paribus) alters the significance of the perceived values that a project must demonstrate in order to attract funding. A total of 337 participants evaluated one of the three variations of the same crowdfunding project with a manipulation of the type of reward that was offered (shares for equity, interest rate for lending and product for reward-based). Our findings validate and extend existing results, confirming the heterogeneity in backers’ decision-to support a project.
A Family of Banach Spaces Over ℝ∞
Authors: Gill Tepper L. , Kalita Hemanta , Hazarika Bipan
Published: March 2021

In T. L. Gill and W. W. Zachary, Functional Analysis and the Feynman Operator Calculus (Springer, New York, 2016), the topology of [Formula: see text] was replaced with a new topology and denoted by [Formula: see text]. This space was then used to construct Lebesgue measure on [Formula: see text] in a manner that is no more difficult than the same construction on [Formula: see text]. More important for us, a new class of separable Banach spaces [Formula: see text], [Formula: see text], for the HK-integrable functions, was introduced. These spaces also contain the [Formula: see text] spaces and the Schwartz space as continuous dense embeddings. This paper extends the work in T. L. Gill and W. W. Zachary, Functional Analysis and the Feynman Operator Calculus (Springer, New York, 2016) from [Formula: see text] to [Formula: see text].