bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of flow regimes in arc plasma–gas interactions using a two-temperature arc in crossflow model
Authors: Bhigamudre V. G. , Trelles J. P.
Published: February 2020

The perpendicular impingement of a gas stream on an electric arc, a configuration known as the arc in crossflow, is of primary relevance in the study of plasma–gas interactions as well as in industrial applications such as circuit breakers and wire-arc spraying. The flow dynamics in the arc in crossflow are the result of coupled fluid-thermal-electromagnetic phenomena accompanied by large property gradients, which can produce significant deviations from Local Thermodynamic Equilibrium (LTE) among electrons and gas species. These characteristics can lead to the establishment of distinct flow regimes depending on the relative values of the controlling parameters of the system, such as inflow velocity, arc current, and inter-electrode spacing. A two-temperature non-LTE model is used to investigate the arc dynamics and the establishment of flow regimes in the arc in crossflow. The plasma flow model is implemented within a nonlinear Variational Multiscale (VMS) numerical discretization approach that is less dissipative and, hence, better suited to capture unstable behavior than traditional VMS methods commonly used in computational fluid dynamics simulations. The Reynolds and the Enthalpy dimensionless numbers, characterizing the relative flow strength and arc strength, respectively, are chosen as the controlling parameters of the system. Simulation results reveal the onset of dynamic behavior and the establishment of steady, periodic, quasi-periodic, and chaotic or potentially turbulent regimes, as identified by distinct spatiotemporal fluctuations. The computational results reveal the role of increasing the relative arc strength on enhancing flow stability by delaying the growth of fluctuating and unstable flow behavior.
Research on fault diagnosis and state assessment of vacuum pump based on acoustic emission sensors
Authors: Rui Xiaobo , Liu Jiawei , Li Yibo , Qi Lei , Li Guangfeng
Published: February 2020

A vacuum pump is a widely used vacuum device and a key component of the space environment simulator. Aiming at the problem of fault diagnosis and state assessment of the vacuum pump, this paper proposes a complete set of empirical mode decomposition [Complete Ensemble Empirical Mode Decomposition with Adaptive Noise (CEEMDAN)] based on adaptive noise and support vector machine optimized by particle swarm optimization (PSO-SVM). The CEEMDAN method can adaptively decompose the acoustic emission signal of the vacuum pump to obtain several eigenmode functions [Intrinsic Mode Functions (IMFs)] and residuals. The normalized energy values of the IMF component are extracted as the eigenvector. The PSO algorithm is used to optimize the key parameters of the SVM, and the samples are used for training to establish a fault diagnosis model. The vacuum pump overload fault and vacuum pump with different working states are judged by experiments. The results show that the method has an accuracy of more than 97.0% and can effectively realize fault diagnosis and state assessment of vacuum pump equipment.
Crossed beam energy transfer in the presence of laser speckle ponderomotive self-focusing and nonlinear sound waves
Authors: Hüller S. , Raj G. , Rozmus W. , Pesme D.
Published: February 2020

Crossed beam energy transfer, CBET, is investigated by taking into account the speckle structure of smoothed laser beams that overlap in a plasma with an inhomogeneous flow profile. Using the two-dimensional simulation code Harmony, it is shown how ponderomotive self-focusing of laser speckles in crossing beams can significantly affect the transfer of energy from one beam to the other. The role of plasma flow in speckle self-focusing is investigated and revisited, in particular its consequences in terms of redirection and increasing angular spread of the laser beams due to beam bending and plasma-induced smoothing, respectively. In close-to-sonic flow, the onset of self-focusing in the beam speckle structure occurs at considerably lower beam intensities than expected for the case without flow. CBET and speckle self-focusing can, hence, occur together when two crossed beams with equal frequency resonantly exchange energy via their ponderomotively driven density perturbations flowing with sound speed. From the simulations, it is found that consequences of ponderomotive self-focusing can be expected above an average intensity threshold scaling as IL∼2×1014 W cm−2(λ0/1 μm)−2(Te/ keV ), with an impact on the spatial and temporal coherence of the transmitted light. The density perturbations due to the ponderomotive force of the crossing beams can locally be enhanced in self-focusing speckles, partly leading to shock-like structures. These structures eventually increase the effect of plasma-induced smoothing and are at the origin of the stronger angular spread.
The ab initio density functional theory applied for spin-polarized calculations
Authors: Śmiga Szymon , Marusiak Volodymyr , Grabowski Ireneusz , Fabiano Eduardo
Published: February 2020

We have performed a systematic and broad study of the performance of the ab initio OEP2-sc functional for spin-polarized systems, including the computation of ionization potentials and atomization and reaction energies of closed- and open-shell molecules. The results have revealed that, in line with other second-order methods, OEP2-sc can provide accurate results, being competitive to the orbital-optimized MP2 method. Moreover, the analysis of total and relative energies has shown that, unlike the case of double-hybrid functionals, this relatively good performance is not based on an error cancellation effect.
Thermodynamics of switching in multistable non-equilibrium systems
Authors: Cook Jacob , Endres Robert G.
Published: February 2020

Multistable non-equilibrium systems are abundant outcomes of nonlinear dynamics with feedback, but still relatively little is known about what determines the stability of the steady states and their switching rates in terms of entropy and entropy production. Here, we will link fluctuation theorems for the entropy production along trajectories with the action obtainable from the Freidlin–Wentzell theorem to elucidate the thermodynamics of switching between states in the large volume limit of multistable systems. We find that the entropy production at steady state plays no role, but the entropy production during switching is key. Steady-state entropy and diffusive noise strength can be neglected in this limit. The relevance to biological, ecological, and climate models is apparent.
Supervised chaotic source separation by a tank of water
Authors: Lu Zhixin , Kim Jason Z. , Bassett Danielle S.
Published: February 2020

Whether listening to overlapping conversations in a crowded room or recording the simultaneous electrical activity of millions of neurons, the natural world abounds with sparse measurements of complex overlapping signals that arise from dynamical processes. While tools that separate mixed signals into linear sources have proven necessary and useful, the underlying equational forms of most natural signals are unknown and nonlinear. Hence, there is a need for a framework that is general enough to extract sources without knowledge of their generating equations and flexible enough to accommodate nonlinear, even chaotic, sources. Here, we provide such a framework, where the sources are chaotic trajectories from independently evolving dynamical systems. We consider the mixture signal as the sum of two chaotic trajectories and propose a supervised learning scheme that extracts the chaotic trajectories from their mixture. Specifically, we recruit a complex dynamical system as an intermediate processor that is constantly driven by the mixture. We then obtain the separated chaotic trajectories based on this intermediate system by training the proper output functions. To demonstrate the generalizability of this framework in silico, we employ a tank of water as the intermediate system and show its success in separating two-part mixtures of various chaotic trajectories. Finally, we relate the underlying mechanism of this method to the state-observer problem. This relation provides a quantitative theory that explains the performance of our method, and why separation is difficult when two source signals are trajectories from the same chaotic system.
Opto-chemo-mechanical transduction in photoresponsive gels elicits switchable self-trapped beams with remote interactions
Authors: Morim Derek R. , Meeks Amos , Shastri Ankita , Tran Andy , Shneidman Anna V. , Yashin Victor V. , Mahmood Fariha , Balazs Anna C. , Aizenberg Joanna , Saravanamuttu Kalaichelvi
Published: February 2020

Significance

Self-trapped light beams hold potential for optical interconnects, applications in image transmission, rerouting light, logic gates for computing and, importantly, for the next-generation light-guiding-light signal processing, which envisions a circuitry-free and reconfigurable photonics powered by the dynamic interactions of self-trapped beams. In conventional nonlinear materials, however, self-trapping suffers from either the need for large incident beam powers and loss of beam interactions at large distances, or it is slow and irreversible. We show that rapidly and repeatably switchable self-trapped laser beams with remote communication capabilities can be elicited at exceptionally small intensities in a pliant, processable hydrogel functionalized with a chromophore. The ability to generate self-trapped beams with this unique set of properties offers unprecedented opportunities to develop light-guiding-light technologies.
Mismatches between demographic niches and geographic distributions are strongest in poorly dispersed and highly persistent plant species
Authors: Pagel Jörn , Treurnicht Martina , Bond William J. , Kraaij Tineke , Nottebrock Henning , Schutte-Vlok AnneLise , Tonnabel Jeanne , Esler Karen J. , Schurr Frank M.
Published: February 2020

Significance

Forecasts of global change impacts on biodiversity often assume that the current geographical distributions of species match their ecological niches. Here we examine this assumption using an extensive dataset of large-scale variation in demographic rates that enables us to quantify demography-based ecological niches of 26 plant species. Contrasting these niches with the species’ geographic distributions reveals that niche–distribution mismatches can be large and depend on key life-history traits: poorly dispersed species are absent from suitable sites, and species with high persistence ability are present in sites that are currently unsuitable for them. Such niche–distribution mismatches need to be accounted for to improve forecasts of biodiversity dynamics under environmental change.
Actin reduction by MsrB2 is a key component of the cytokinetic abscission checkpoint and prevents tetraploidy
Authors: Bai Jian , Wioland Hugo , Advedissian Tamara , Cuvelier Frédérique , Romet-Lemonne Guillaume , Echard Arnaud
Published: February 2020

Abscission is the terminal step of cytokinesis leading to the physical separation of the daughter cells. In response to the abnormal presence of lagging chromatin between dividing cells, an evolutionarily conserved abscission/NoCut checkpoint delays abscission and prevents formation of binucleated cells by stabilizing the cytokinetic intercellular bridge (ICB). How this bridge is stably maintained for hours while the checkpoint is activated is poorly understood and has been proposed to rely on F-actin in the bridge region. Here, we show that actin polymerization is indeed essential for stabilizing the ICB when lagging chromatin is present, but not in normal dividing cells. Mechanistically, we found that a cytosolic pool of human methionine sulfoxide reductase B2 (MsrB2) is strongly recruited at the midbody in response to the presence of lagging chromatin and functions within the ICB to promote actin polymerization there. Consistently, in MsrB2-depleted cells, F-actin levels are decreased in ICBs, and dividing cells with lagging chromatin become binucleated as a consequence of unstable bridges. We further demonstrate that MsrB2 selectively reduces oxidized actin monomers and thereby counteracts MICAL1, an enzyme known to depolymerize actin filaments by direct oxidation. Finally, MsrB2 colocalizes and genetically interacts with the checkpoint components Aurora B and ANCHR, and the abscission delay upon checkpoint activation by nuclear pore defects also depends on MsrB2. Altogether, this work reveals that actin reduction by MsrB2 is a key component of the abscission checkpoint that favors F-actin polymerization and limits tetraploidy, a starting point for tumorigenesis.
Loss of phenotypic inheritance associated with
ydcI
mutation leads to increased frequency of small, slow persisters in
Escherichia coli
Authors: Hingley-Wilson Suzanne M. , Ma Nan , Hu Yin , Casey Rosalyn , Bramming Anders , Curry Richard J. , Tang Hongying Lilian , Wu Huihai , Butler Rachel E. , Jacobs William R. , Rocco Andrea , McFadden Johnjoe
Published: February 2020

Whenever a genetically homogenous population of bacterial cells is exposed to antibiotics, a tiny fraction of cells survives the treatment, the phenomenon known as bacterial persistence [G.L. Hobby
et al.
,
Exp. Biol. Med.
50, 281–285 (1942); J. Bigger,
The Lancet
244, 497–500 (1944)]. Despite its biomedical relevance, the origin of the phenomenon is still unknown, and as a rare, phenotypically resistant subpopulation, persisters are notoriously hard to study and define. Using computerized tracking we show that persisters are small at birth and slowly replicating. We also determine that the high-persister mutant strain of
Escherichia coli
,
HipQ
, is associated with the phenotype of reduced phenotypic inheritance (RPI). We identify the gene responsible for RPI,
ydcI
, which encodes a transcription factor, and propose a mechanism whereby loss of phenotypic inheritance causes increased frequency of persisters. These results provide insight into the generation and maintenance of phenotypic variation and provide potential targets for the development of therapeutic strategies that tackle persistence in bacterial infections.
Transdermal cold atmospheric plasma-mediated immune checkpoint blockade therapy
Authors: Chen Guojun , Chen Zhitong , Wen Di , Wang Zejun , Li Hongjun , Zeng Yi , Dotti Gianpietro , Wirz Richard E. , Gu Zhen
Published: February 2020

Significance

Strategies to improve efficacy and reduce side effects of immune checkpoint blockade (ICB) therapy are clinically relevant. Here, we described a transdermal cold atmospheric plasma (CAP)-mediated ICB therapy. Local delivery of CAP through hollow-structured microneedles as microchannels promote the release of tumor-associated antigens by CAP. The subsequent T cell-mediated immune response can be augmented by the immune checkpoint inhibitors delivered via microneedles, resulting in enhanced local and systemic anticancer immunity. The synergism between CAP and ICB integrated with microneedles provides a platform technique for cancer treatment and other diseases in a minimally invasive manner.
Lack of RAN-mediated toxicity in Huntington’s disease knock-in mice
Authors: Yang Su , Yang Huiming , Huang Luoxiu , Chen Luxiao , Qin Zhaohui , Li Shihua , Li Xiao-Jiang
Published: February 2020

Identification of repeat-associated non-AUG (RAN) translation in trinucleotide (CAG) repeat diseases has led to the emerging concept that CAG repeat diseases are caused by nonpolyglutamine products. Nonetheless, the in vivo contribution of RAN translation to the pathogenesis of CAG repeat diseases remains elusive. Via CRISPR/Cas9-mediated genome editing, we established knock-in mouse models that harbor expanded CAG repeats in the mouse
huntingtin
gene to express RAN-translated products with or without polyglutamine peptides. We found that RAN translation is not detected in the knock-in mouse models when expanded CAG repeats are expressed at the endogenous level. Consistently, the expanded CAG repeats that cannot be translated into polyglutamine repeats do not yield the neuropathological and behavioral phenotypes that were found in knock-in mice expressing expanded polyglutamine repeats. Our findings suggest that RAN-translated products do not play a major role in the pathogenesis of CAG repeat diseases and underscore the importance in targeting polyglutamine repeats for therapeutics.
Spacetimes with all Penrose limits diagonalisable*
Authors: Tod Paul
Published: February 2020

We consider the problem of finding all space-time metrics for which all plane-wave Penrose limits are diagonalisable plane waves. This requirement leads to a conformally invariant differential condition on the Weyl spinor which we analyse for different algebraic types in the Petrov–Pirani–Penrose classification. The only vacuum examples, apart from actual plane waves which are their own Penrose limit, are some of the nonrotating type D metrics, but some nonvacuum solutions are also identified. The condition requires the Weyl spinor, whenever it is nonzero, to be proportional to a valence-4 Killing spinor with a real function of proportionality.
Particle dance: particle physics in the dance studio
Authors: Nikolopoulos K , Pardalaki M
Published: February 2020

A workshop using dance to introduce particle physics concepts to young children is presented. The workshop is realised in the dance studio, the children assume complete ownership of the activity and dance becomes the means to express ideas. The embodiement of the physics concepts facilitates knowledge assimilation, while empowering the students with respect to science. Beyond the scientific and artistic benefits of this workshop, this approach aspires to overcome the barriers between art and science; and open new interdisciplinary horizons for the students.
Cloud shape of a molecular Bose–Einstein condensate in a disordered trap: a case study of the dirty boson problem
Authors: Nagler Benjamin , Radonjić Milan , Barbosa Sian , Koch Jennifer , Pelster Axel , Widera Artur
Published: February 2020

We investigate, both experimentally and theoretically, the static geometric properties of a harmonically trapped Bose–Einstein condensate of 6Li2 molecules in laser speckle potentials. Experimentally, we measure the in situ column density profiles and the corresponding transverse cloud widths over many laser speckle realizations. We compare the measured widths with a theory that is non-perturbative with respect to the disorder and includes quantum fluctuations. Importantly, for small disorder strengths we find quantitative agreement with the perturbative approach of Huang and Meng, which is based on Bogoliubov theory. For strong disorder our theory perfectly reproduces the geometric mean of the measured transverse widths. However, we also observe a systematic deviation of the individual measured widths from the theoretically predicted ones. In fact, the measured cloud aspect ratio monotonously decreases with increasing disorder strength, while the theory yields a constant ratio. We attribute this discrepancy to the utilized local density approximation, whose possible failure for strong disorder suggests a potential future improvement.
Continuous feedback on a quantum gas coupled to an optical cavity
Authors: Kroeger Katrin , Dogra Nishant , Rosa-Medina Rodrigo , Paluch Marcin , Ferri Francesco , Donner Tobias , Esslinger Tilman
Published: February 2020

We present an active feedback scheme acting continuously on the state of a quantum gas dispersively coupled to a high-finesse optical cavity. The quantum gas is subject to a transverse pump laser field inducing a self-organization phase transition, where the gas acquires a density modulation and photons are scattered into the resonator. Photons leaking from the cavity allow for a real-time and non-destructive readout of the system. We stabilize the mean intra-cavity photon number through a micro-processor controlled feedback architecture acting on the intensity of the transverse pump field. The feedback scheme can keep the mean intra-cavity photon number n
ph constant, in a range between n
ph = 0.17(4) and n
ph = 27.6(5), and for up to 4 s. Thus we can engage the stabilization in a regime where the system is very close to criticality as well as deep in the self-organized phase. The presented scheme allows us to approach the self-organization phase transition in a highly controlled manner and is a first step on the path towards the realization of many-body phases driven by tailored feedback mechanisms.
Small Target Recognition Using Dynamic Time Warping and Visual Attention
Authors: Zhang Xinpeng , Wu Jigang , Meng Min
Published: February 2020

Microaneurysm is a kind of small targets in color retinal image, and it is an essential work to recognize the small target for the early diagnosis of diabetic retinopathy. This paper proposes an efficient method to accurately recognize microaneurysm. A symmetric extended curvature Gabor wavelet is presented to generate candidate objects, where some novel features are extracted for classification. A kind of statistic features is generated to distinguish between microaneurysm and thin vessels, in terms of the shape similarity of cross-section profiles. Furthermore, the visual attention-based features are proposed to compute local contrast of small targets in complex background. Random undersampling with AdaBoost (RUSBoost) classifier is employed to discriminate true microaneurysm from an overwhelming amount of candidate objects. Experimental results demonstrate that the proposed method achieves significant sensitivity and accuracy on the public datasets, in comparison to the state-of-the-arts.
3D biofilms: in search of the polysaccharides holding together lichen symbioses
Authors: Spribille Toby , Tagirdzhanova Gulnara , Goyette Spencer , Tuovinen Veera , Case Rebecca , Zandberg Wesley F
Published: February 2020

Stable, long-term interactions between fungi and algae or cyanobacteria, collectively known as lichens, have repeatedly evolved complex architectures with little resemblance to their component parts. Lacking any central scaffold, the shapes they assume are casts of secreted polymers that cement cells into place, determine the angle of phototropic exposure and regulate water relations. A growing body of evidence suggests that many lichen extracellular polymer matrices harbor unicellular, non-photosynthesizing organisms (UNPOs) not traditionally recognized as lichen symbionts. Understanding organismal input and uptake in this layer is key to interpreting the role UNPOs play in lichen biology. Here, we review both polysaccharide composition determined from whole, pulverized lichens and UNPOs reported from lichens to date. Most reported polysaccharides are thought to be structural cell wall components. The composition of the extracellular matrix is not definitively known. Several lines of evidence suggest some acidic polysaccharides have evaded detection in routine analysis of neutral sugars and may be involved in the extracellular matrix. UNPOs reported from lichens include diverse bacteria and yeasts for which secreted polysaccharides play important biological roles. We conclude by proposing testable hypotheses on the role that symbiont give-and-take in this layer could play in determining or modifying lichen symbiotic outcomes.
Estimating the relative probability of direct transmission between infectious disease patients
Authors: Leavitt Sarah V , Lee Robyn S , Sebastiani Paola , Horsburgh C Robert , Jenkins Helen E , White Laura F
Published: February 2020

Background

Estimating infectious disease parameters such as the serial interval (time between symptom onset in primary and secondary cases) and reproductive number (average number of secondary cases produced by a primary case) are important in understanding infectious disease dynamics. Many estimation methods require linking cases by direct transmission, a difficult task for most diseases.

Methods

Using a subset of cases with detailed genetic and/or contact investigation data to develop a training set of probable transmission events, we build a model to estimate the relative transmission probability for all case-pairs from demographic, spatial and clinical data. Our method is based on naive Bayes, a machine learning classification algorithm which uses the observed frequencies in the training dataset to estimate the probability that a pair is linked given a set of covariates.

Results

In simulations, we find that the probabilities estimated using genetic distance between cases to define training transmission events are able to distinguish between truly linked and unlinked pairs with high accuracy (area under the receiver operating curve value of 95%). Additionally, only a subset of the cases, 10–50% depending on sample size, need to have detailed genetic data for our method to perform well. We show how these probabilities can be used to estimate the average effective reproductive number and apply our method to a tuberculosis outbreak in Hamburg, Germany.

Conclusions

Our method is a novel way to infer transmission dynamics in any dataset when only a subset of cases has rich contact investigation and/or genetic data.
Immunological and Inflammatory Biomarkers of Susceptibility and Severity in Adult Respiratory Syncytial Virus Infections
Authors: Wiseman Dexter J , Thwaites Ryan S , Drysdale Simon B , Janet Sophie , Donaldson Gavin C , Wedzicha Jadwiga A , Openshaw Peter J ,   RESCEU Investigators, Nair Harish , Campbell Harry , Shi Ting , Zhang Shanshan , Li You , Openshaw Peter , Wedzicha Jadwiga , Falsey Ann , Miller Mark , Beutels Philippe , Bont Louis , Pollard Andrew , Molero Eva , Martinon-Torres Federico , Heikkinen Terho , Meijer Adam , Kølsen Fischer Thea , van den Berge Maarten , Giaquinto Carlo , Mikolajczyk Rafael , Hackett Judy , Tafesse Eskinder , Cai Bing , Knirsch Charles , Gonzalez Lopez Antonio , Dieussaert Ilse , Dermateau Nadia , Stoszek Sonia , Gallichan Scott , Kieffer Alexia , Demont Clarisse , Cheret Arnaud , Gavart Sandra , Aerssens Jeroen , Wyffels Veronique , Cleenewerck Matthias , Fuentes Robert , Rosen Brian , Nair Harish , Campbell Harry , Shi Ting , Zhang Shanshan , Li You , Openshaw Peter , Wedzicha Jadwiga , Falsey Ann , Miller Mark , Beutels Philippe , Bont Louis , Pollard Andrew , Molero Eva , Martinon-Torres Federico , Heikkinen Terho , Meijer Adam , Kølsen Fischer Thea , van den Berge Maarten , Giaquinto Carlo , Mikolajczyk Rafael , Hackett Judy , Tafesse Eskinder , Cai Bing , Knirsch Charles , Gonzalez Lopez Antonio , Dieussaert Ilse , Dermateau Nadia , Stoszek Sonia , Gallichan Scott , Kieffer Alexia , Demont Clarisse , Cheret Arnaud , Gavart Sandra , Aerssens Jeroen , Wyffels Veronique , Cleenewerck Matthias , Fuentes Robert , Rosen Brian
Published: February 2020

Background

Respiratory syncytial virus (RSV) is the most common cause of bronchiolitis in young infants. However, it is also a significant pathogen in older adults. Validated biomarkers of RSV disease severity would benefit diagnostics, treatment decisions, and prophylactic interventions. This review summarizes knowledge of biomarkers for RSV disease in adults.

Methods

A literature review was performed using Ovid Medline, Embase, Global health, Scopus, and Web of Science for articles published 1946–October 2016. Nine articles were identified plus 9 from other sources.

Results

From observational studies of natural infection and challenge studies in volunteers, biomarkers of RSV susceptibility or disease severity in adults were: (1) lower anti-RSV neutralizing antibodies, where neutralizing antibody (and local IgA) may be a correlate of susceptibility/severity; (2) RSV-specific CD8+ T cells in bronchoalveolar lavage fluid preinfection (subjects with higher levels had less severe illness); and (3) elevated interleukin-6 (IL-6), IL-8, and myeloperoxidase levels in the airway are indicative of severe infection.

Conclusions

Factors determining susceptibility to and severity of RSV disease in adults have not been well defined. Respiratory mucosal antibodies and CD8+ T cells appear to contribute to preventing infection and modulation of disease severity. Studies of RSV pathogenesis in at-risk populations are needed.
Characteristics and Outcomes of ERCP at a Canadian Tertiary Centre: Initial Results from a Prospective High-Fidelity Biliary Endoscopy Registry
Authors: Forbes Nauzer , Koury Hannah F , Bass Sydney , Cole Martin , Mohamed Rachid , Turbide Christian , Gonzalez-Moreno Emmanuel , Kayal Ahmed , Chau Millie , Lethebe B Cord , Hilsden Robert J , Heitman Steven J
Published: February 2020

Background

Endoscopic retrograde cholangiopancreatography (ERCP) is an essential procedure in the management of pancreatic and biliary disease. While its role is firmly established, further well-designed prospective ERCP research is required, as a large portion of previous work has employed retrospective or administrative methodologies, both prone to potential biases. The aim of the Calgary Registry for Advanced and Therapeutic Endoscopy (CReATE) is to be a high-fidelity prospective multicentre registry.

Methods

The study population consisted of consecutive adult ERCP patients from September 2018 to September 2019. Informed consent was acquired for each patient. All relevant preprocedural, procedural, peri-procedural and postprocedural data were captured in real time by a full-time third-party research assistant directly observing procedures. Outcomes were ascertained by comprehensive medical record review and patient phone interview 30 days after the index procedure.

Results

Five endoscopists performed 895 ERCP procedures, 90.1% of which were deemed successful. Suspected choledocholithiasis was the most common indication for ERCP, followed by suspected or confirmed stricture(s), at 61.0% and 29.5%, respectively. 61.0% of procedures were performed on ERCP-naive patients. Post-ERCP pancreatitis occurred following 4.9% of procedures, with clinically significant bleeding or perforation occurring following 1.8% and 0.1% of procedures, respectively.

Discussion

Through 12 months, CReATE captured 895 procedures prospectively, with each entry containing over 300 data fields. Active expansion to additional tertiary centres is underway, and this will enhance the existing data pool. CReATE has the potential to improve multiple facets of ERCP, including training, optimal procedural techniques, mitigation of adverse events and personalized patient care.
Systematic Review of Health Literacy in Childhood Cancer Patients, Survivors, and Their Caregivers
Authors: Lynn Courtney , Quast Lauren , Rogers Hannah , Effinger Karen , Gilleland-Marchak Jordan
Published: February 2020

Objective

This systematic review examined the literature regarding health literacy among pediatric cancer patients, survivors, and their caregivers. Specific aims were to identify and summarize measures used, levels of and demographic correlates of health literacy, effects of health literacy interventions, and associations between health literacy and health outcomes.

Methods

The search strategy was executed in the following databases: PubMed, EMBASE, PsycINFO, CINAHL, ERIC, and the Cochrane Library. Of the 842 unique studies retrieved, 9 met the inclusion criteria and were included in the systematic review.

Results

Studies used a variety of validated and study-specific measures with no measure emerging as the standard. Levels of health literacy were typically assessed subjectively and across studies the majority of those sampled self-reported adequate health literacy. Few studies examined demographic correlates of health literacy, precluding the identification of consistent predictors. Health literacy intervention research for this population is in its infancy and only pilot projects were identified; effects could not be evaluated. No studies assessed the impact of health literacy on health outcomes.

Conclusions

Very few studies assessed health literacy in pediatric oncology. As treatment for childhood cancer becomes increasingly complex, and patients and caregivers are expected to have adequate understanding of health information, health literacy is a critical construct that should not be overlooked.
A case of peeping testis moving from the inguinal position into the abdomen
Authors: Tatekawa Yukihiro
Published: February 2020

We report herein a 14-month-old boy with a left-sided peeping testis. At the age of 1 month, the left testis was palpated between the inguinal canal and the scrotum. When he was 6 months old, ultrasonography showed the left testis in the inguinal canal. At the age of 13 months, the left testis was not palpable. At the age of 14 months, he underwent surgery for a planned inguinal orchidopexy with a preoperative diagnosis of an undescended testis. When the inguinal canal was opened, a patent processus vaginalis was observed and the testis was found inside the abdominal cavity. The patent processus vaginalis was closed, a dartos pouch was created and the testis was guided into the pouch and fixed to its wall. We describe a case of a peeping testis moving from the inguinal position into the abdomen.
SN 2016gsd: an unusually luminous and linear Type II supernova with high velocities
Authors: Reynolds T M , Fraser M , Mattila S , Ergon M , Dessart L , Lundqvist P , Dong Subo , Elias-Rosa N , Galbany L , Gutiérrez C P , Kangas T , Kankare E , Kotak R , Kuncarayakti H , Pastorello A , Rodriguez O , Smartt S J , Stritzinger M , Tomasella L , Chen Ping , Harmanen J , Hosseinzadeh G , Howell D Andrew , Inserra C , Nicholl M , Nielsen M , Smith K , Somero A , Tronsgaard R , Young D R
Published: February 2020

We present observations of the unusually luminous Type II supernova (SN) 2016gsd. With a peak absolute magnitude of V = −19.95 ± 0.08, this object is one of the brightest Type II SNe, and lies in the gap of magnitudes between the majority of Type II SNe and the superluminous SNe. Its light curve shows little evidence of the expected drop from the optically thick phase to the radioactively powered tail. The velocities derived from the absorption in H α are also unusually high with the blue edge tracing the fastest moving gas initially at 20 000 km s−1, and then declining approximately linearly to 15 000 km s−1 over ∼100 d. The dwarf host galaxy of the SN indicates a low-metallicity progenitor which may also contribute to the weakness of the metal lines in its spectra. We examine SN 2016gsd with reference to similarly luminous, linear Type II SNe such as SNe 1979C and 1998S, and discuss the interpretation of its observational characteristics. We compare the observations with a model produced by the jekyll code and find that a massive star with a depleted and inflated hydrogen envelope struggles to reproduce the high luminosity and extreme linearity of SN 2016gsd. Instead, we suggest that the influence of interaction between the SN ejecta and circumstellar material can explain the majority of the observed properties of the SN. The high velocities and strong H α absorption present throughout the evolution of the SN may imply a circumstellar medium configured in an asymmetric geometry.
Convection with misaligned gravity and rotation: simulations and rotating mixing length theory
Authors: Currie Laura K , Barker Adrian J , Lithwick Yoram , Browning Matthew K
Published: February 2020

We present numerical simulations, using two complementary set-ups, of rotating Boussinesq thermal convection in a three-dimensional Cartesian geometry with misaligned gravity and rotation vectors. This model represents a small region at a non-polar latitude in the convection zone of a star or planet. We investigate the effects of rotation on the bulk properties of convection at different latitudes, focusing on determining the relation between the heat flux and temperature gradient. We show that our results may be interpreted using rotating mixing length theory (RMLT). The simplest version of RMLT (due to Stevenson) considers the single mode that transports the most heat. This works reasonably well in explaining our results, but there is a systematic departure from these predictions (up to approximately $30{{\ \rm per\ cent}}$ in the temperature gradient) at mid-latitudes. We develop a more detailed treatment of RMLT that includes the transport afforded by multiple modes, and we show that this accounts for most of the systematic differences. We also show that convectively generated zonal flows and meridional circulations are produced in our simulations, and that their properties depend strongly on the dimensions of the box. These flows also affect the heat transport, contributing to departures from RMLT at some latitudes. However, we find the theoretical predictions of the multi-mode theory for the mid-layer temperature gradient, the root-mean-square (rms) vertical velocity, the rms temperature fluctuation, and the spatial spectrum of the heat transport at different latitudes are all in reasonably good agreement with our numerical results when zonal flows are small.
The faint host galaxies of C IV absorbers at z > 5
Authors: Finlator Kristian , Doughty Caitlin , Cai Zheng , Díaz Gonzalo
Published: February 2020

We explore the expected galaxy environments of $\mathrm{C\, \small {IV}}$ absorbers at z > 5 using the Technicolor Dawn simulations. These simulations reproduce the observed history of reionization, the z ∼ 6 galaxy stellar mass function, the Ly α forest transmission at z > 5, and the $\mathrm{Si\, \small {IV}}$ column density distribution (CDD) at z ≈ 5.5. None the less, the $\mathrm{C\, \small {IV}}$ CDD remains underproduced. Comparison with observed $\mathrm{C\, \small {II}}/\mathrm{Si\, \small {II}}$ equivalent width ratios and the $\mathrm{C\, \small {II}}$ line incidence suggests that a low carbon yield accounts for some, but not all, of the $\mathrm{C\, \small {IV}}$ discrepancy. Alternatively, a density-bounded escape scenario could harden the metagalactic ionizing background more dramatically even than binary stellar evolution, boosting the $\mathrm{C\, \small {IV}}$ CDD into near agreement with observations. In this case, galaxies ionize more efficiently and fewer are required to host a given high-ionization absorber. Absorbers’ environments therefore constrain ionizing escape. Regardless of the escape scenario, galaxies correlate with $\mathrm{C\, \small {IV}}$ absorbers out to 300 proper kpc (pkpc). The correlation strengthens independently with galaxy luminosity and $\mathrm{C\, \small {IV}}$ column density. Around strong systems ($\log (N_\mathrm{C\, \small {IV}}/{\rm cm}^{-2})\gt 14)$), the overdensity of galaxies with MUV < −18 or log (LLy α/erg s−1) > 41.9 declines from 200–300 within 100 pkpc to 40–60 within 250 pkpc. The previously suggested association between strong $\mathrm{C\, \small {IV}}$ absorbers and Ly α emitters at z > 5 is not expected. It may arise if both populations inhabit large-scale voids, but for different reasons. Although most neighbouring galaxies are too faint for HST, JWST will, with a single pointing, identify ∼10 neighbouring galaxies per strong $\mathrm{C\, \small {IV}}$ absorber at z > 5. Ground-based tests of these predictions are possible via deep surveys for Ly α emission using integral field units.
Evolution of porous dust grains in protoplanetary discs – I. Growing grains
Authors: Garcia Anthony J L , Gonzalez Jean-François
Published: February 2020

One of the main problems in planet formation, hampering the growth of small dust to planetesimals, is the so-called radial-drift barrier. Pebbles of cm to dm sizes are thought to drift radially across protoplanetary discs faster than they can grow to larger sizes, and thus to be lost to the star. To overcome this barrier, drift has to be slowed down or stopped, or growth needs to be sped up. In this paper, we investigate the role of porosity on both drift and growth. We have developed a model for porosity evolution during grain growth and applied it to numerical simulations of protoplanetary discs. We find that growth is faster for porous grains, enabling them to transition to the Stokes drag regime, decouple from the gas, and survive the radial-drift barrier. Direct formation of small planetesimals from porous dust is possible over large areas of the disc.
Classification of blazar candidates of uncertain type from the Fermi LAT 8-yr source catalogue with an artificial neural network
Authors: Kovačević M , Chiaro G , Cutini S , Tosti G
Published: February 2020

The Fermi Large Area Telescope (LAT) has detected more than 5000 γ-ray sources in its first 8 yr of operation. More than 3000 of them are blazars. About 60 per cent of the Fermi-LAT blazars are classified as BL Lacertae objects (BL Lacs) or Flat Spectrum Radio Quasars (FSRQs), while the rest remain of uncertain type. The goal of this study was to classify those blazars of uncertain type, using a supervised machine learning method based on an artificial neural network, by comparing their properties to those of known γ-ray sources. Probabilities for each of 1329 uncertain blazars to be a BL Lac or FSRQ are obtained. Using 90 per cent precision metric, 801 can be classified as BL Lacs and 406 as FSRQs while 122 still remain unclassified. This approach is of interest because it gives a fast preliminary classification of uncertain blazars. We also explored how different selections of training and testing samples affect the classification and discuss the meaning of network outputs.
Clusterix 2.0: a virtual observatory tool to estimate cluster membership probability
Authors: Balaguer-Núñez L , López del Fresno M , Solano E , Galadí-Enríquez D , Jordi C , Jimenez-Esteban F , Masana E , Carbajo-Hijarrubia J , Paunzen E
Published: February 2020

Clusterix 2.0 is a web-based, Virtual Observatory compliant, interactive tool for the determination of membership probabilities in stellar clusters based on proper-motion data using a fully non-parametric method. In an area occupied by a cluster, the frequency function is made up of two contributions: cluster and field stars. The tool performs an empirical determination of the frequency functions from the vector point diagram without relying on any previous assumption about their profiles. Clusterix 2.0 allows us to search the appropriate spatial areas in an interactive way until an optimal separation of the two populations is obtained. Several parameters can be adjusted to make the calculation computationally feasible without interfering with the quality of the results. The system offers the possibility to query different catalogues, such as Gaia, or upload a user’s own data. The results of the membership determination can be sent via Simple Application Messaging Protocol (SAMP) to Virtual Observatory (VO) tools such as Tool for OPerations on Catalogues And Tables (TOPCAT). We apply Clusterix 2.0 to several open clusters with different properties and environments to show the capabilities of the tool: an area of five degrees radius around NGC 2682 (M67), an old, well-known cluster; a young cluster NGC 2516 with a striking elongated structure extended up to four degrees; NGC 1750 and NGC 1758, a pair of partly overlapping clusters; the area of NGC 1817, where we confirm a little-known cluster, Juchert 23; and an area with many clusters, where we disentangle two overlapping clusters situated where only one was previously known: Ruprecht 26 and the new Clusterix 1.
Texturally Controlled U–Th–Pb Monazite Geochronology Reveals Paleoproterozoic UHT Metamorphic Evolution in the Khondalite Belt, North China Craton
Authors: Jiao Shujuan , Fitzsimons Ian C W , Zi Jian-Wei , Evans Noreen J , Mcdonald Brad J , Guo Jinghui
Published: February 2020

Sapphirine-bearing UHT granulites from the Dongpo locality in the Khondalite Belt of the North China Craton have been comprehensively characterized in terms of petrology, mineral chemistry, metamorphic evolution and zircon geochronology. However, the precise timing of the peak-UHT metamorphism and other key stages in the P–T–t evolution remain controversial due to the complexity of multiple metamorphic overprints and the lack of petrographic context for zircon age data. In this study, monazite from four samples of the Dongpo granulite are divided into six groups based on chemical composition and textural context, and dated (in-situ SHRIMP and LA–ICP–MS U–Pb). An age population of 1·91–1·88 Ga was obtained from high-Y cores of monazite inclusions in garnet (Group 1) and on grains in the rock matrix (Group 2). The maximum age of c.1·91 Ga is interpreted as the minimum timing for prograde metamorphism before UHT metamorphism (M1). An age population of 1·90–1·85 Ga was obtained from low-Y domains of monazite inclusions (Group 3) and of matrix grains (Group 4). Combined with previous zircon dating results, the age population from low-Y Mnz constrains the timing and duration of the UHT metamorphism to 1·90–1·85 Ga and 50 (±15) million years, respectively. The large (50 m.y.) age spread is interpreted to reflect continuous monazite formation, and it is consistent with the slow post-peak near-isobaric cooling stage (M2). An age of c.1·86 Ga was obtained from monazite in textural contact with sapphirine/spinel + plagioclase intergrowths (Group 5), which is interpreted as the timing of the subsequent decompression–heating stage (M3). The younger age clusters at c.1·80 and 1·77 Ga, obtained from Th-rich monazite rims (Group 6) and one single Th-depleted monazite in textural contact with matrix biotite, respectively, indicate dissolution–reprecipitation and new monazite growth from fluid released by crystallizing anatectic melt during retrogression. These results, along with the previous 1·93–1·91 Ga data for UHT metamorphism, suggest that there was a very long-lived Paleoproterozoic UHT metamorphism (1·93–1·85 Ga) in the Khondalite Belt of the North China Craton. This supports the large hot orogeny model for the generation of Paleoproterozoic UHT metamorphism in the Khondalite Belt during the amalgamation of the Nuna supercontinent.
Aided Hearing Moderates the Academic Outcomes of Children With Mild to Severe Hearing Loss
Authors: Tomblin J. Bruce , Oleson Jake , Ambrose Sophie E. , Walker Elizabeth A. , McCreery Ryan W. , Moeller Mary Pat
Published: February 2020

Objectives:

There are very limited data regarding the spoken language and academic outcomes of children with mild to severe hearing loss (HL) during the elementary school years, and the findings of these studies are inconsistent. None of these studies have examined the possible role of aided hearing in these outcomes. This study used a large cohort of children to examine these outcomes and in particular to examine whether aided hearing moderates the effect of HL with regard to these outcomes.

Design:

The spoken language, reading, writing, and calculation abilities were measured after second and fourth grades in children with mild to severe HL (children who are hard of hearing; CHH, n = 183) and a group of children with normal hearing (CNH, n = 91) after the completion of second and fourth grades. Also, among the CHH who wore hearing aids, aided better-ear speech intelligibility index values at the age of school entry were obtained.

Results:

Oral language abilities of the CHH with mild and moderate HL were similar to the CNH at each grade. Children with moderately-severe HL (better-ear pure tone threshold >59 but <76 dB HL) had significantly poorer oral language and reading skills than the CNH at each grade. The children with mild and moderate HL did not differ from the CNH in oral language or reading. No differences were found between the CHH regardless of severity and CNH with regard to spelling, passage writing, or calculation. The degree to which hearing aids provided audible speech information played a moderating role in the oral language outcomes of CHH and this moderation of language mediated the relationship between the unaided hearing ability of the CHH and their academic outcomes.

Conclusions:

As a group, children with mild and moderate HL have good outcomes with regard to language and academic performance. Children with moderately-severe losses were less skilled in language and reading than the CNH and CHH children with mild and moderate losses. Audibility provided by hearing aids was found to moderate the effects of HL with respect to these outcomes. These findings emphasize the importance of including the effects of clinical interventions such as aided hearing when examining outcomes of CHH.