bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterising young visual M-dwarf binaries with near-infrared integral field spectra
Authors: Calissendorff Per , Janson Markus , Bonnefoy Mickaël
Published: August 2020

We present the results from an integral field spectroscopy study of seven close visual binary pairs of young M-dwarf multiple systems. The target systems are part of the astrometric monitoring AstraLux programme, surveying hundreds of M-dwarf systems for multiplicity and obtaining astrometric epochs for orbital constraints. Our new VLT/SINFONI data provides resolved spectral type classifications in the J, H, and K bands for seven of these low-mass M-dwarf binaries, which we determine by comparing them to empirical templates and examining the strength of water absorption in the K band. The medium resolution K-band spectra also allows us to derive effective temperatures for the individual components. All targets in the survey display several signs of youth, and some have kinematics similar to young moving groups, or low surface gravities which we determined from measuring equivalent widths of gravity sensitive alkali lines in the J band. Resolved photometry from our targets is also compared with isochrones from theoretical evolutionary models, further implying young ages. Dynamical masses will be provided from continued monitoring of these systems, which can be seen as emblematic binary benchmarks that may be used to calibrate evolutionary models for low-mass stars in the future.
Ejection of close-in super-Earths around low-mass stars in the giant impact stage
Authors: Matsumoto Yuji , Gu Pin-Gao , Kokubo Eiichiro , Oshino Shoichi , Omiya Masashi
Published: August 2020

Context.Earth-sized planets were observed in close-in orbits around M dwarfs. While more and more planets are expected to be uncovered around M dwarfs, theories of their formation and dynamical evolution are still in their infancy.

Aims.We investigate the giant impact stage for the growth of protoplanets, which includes strong scattering around low-mass stars. The aim is to clarify whether strong scattering around low-mass stars affects the orbital and mass distributions of the planets.

Methods.We performed anN-body simulation of protoplanets by systematically surveying the parameter space of the stellar mass and surface density of protoplanets.

Results.We find that protoplanets are often ejected after twice or three times the close-scattering around late M dwarfs. The ejection sets the upper limit of the largest planet mass. By adopting the surface density that linearly scales with the stellar mass, we find that as the stellar mass decreases, less massive planets are formed in orbits with higher eccentricities and inclinations. Under this scaling, we also find that a few close-in protoplanets are generally ejected.

Conclusions.The ejection of protoplanets plays an important role in the mass distribution of super-Earths around late M dwarfs. The mass relation of observed close-in super-Earths and their central star mass is reproduced well by ejection.
Formation of low-spinning 100 M⊙ black holes
Authors: Belczynski K. , Banerjee S.
Published: August 2020

Aims. It is speculated that a merger of two massive stellar-origin black holes in a dense stellar environment may lead to the formation of a massive black hole in the pair-instability mass gap (∼50−135 M⊙). Such a merger-formed black hole is expected to typically have a high spin (a ∼ 0.7). If such a massive black hole acquires another black hole it may lead to another merger detectable by LIGO/Virgo in gravitational waves. Acquiring a companion may be hindered by gravitational-wave kick/recoil, which accompanies the first merger and may quickly remove the massive black hole from its parent globular or nuclear cluster. We test whether it is possible for a massive merger-formed black hole in the pair-instability gap to be retained in its parent cluster and have low spin. Such a black hole would be indistinguishable from a primordial black hole.

Methods. We employed results from numerical relativity calculations of black hole mergers to explore the range of gravitational-wave recoil velocities for various combinations of merging black hole masses and spins. We compared merger-formed massive black hole speeds with typical escape velocities from globular and nuclear clusters.

Results. We show that a globular cluster is highly unlikely to form and retain a ∼100 M⊙ black hole if the spin of the black hole is low (a ≲ 0.3). Massive merger-formed black holes with low spins acquire high recoil speeds (≳ 200 km s−1) from gravitational-wave kick during formation that exceed typical escape speeds from globular clusters (∼ 50 km s−1). However, a very low-spinning (a ∼ 0.1) and massive (∼100 M⊙) black hole could be formed and retained in a galactic nuclear star cluster. Even though such massive merger-formed black holes with such low spins acquire high speeds during formation (∼ 400 km s−1), they may avoid ejection since massive nuclear clusters have high escape velocities (∼ 300−500 km s−1). A future detection of a massive black hole in the pair-instability mass gap with low spin would therefore not be proof of the existence of primordial black holes, which are sometimes claimed to have low spins and arbitrarily high masses.
The first detection of ultra-diffuse galaxies in the Hydra I cluster from the VEGAS survey
Authors: Iodice E. , Cantiello M. , Hilker M. , Rejkuba M. , Arnaboldi M. , Spavone M. , Greggio L. , Forbes D. A. , D’Ago G. , Mieske S. , Spiniello C. , La Marca A. , Rampazzo R. , Paolillo M. , Capaccioli M. , Schipani P.
Published: August 2020

In this paper, we report the discovery of 27 low-surface brightness galaxies, of which 12 are candidates for ultra-diffuse galaxies (UDG) in the Hydra I cluster, based on deep observations taken as part of the VST Early-type Galaxy Survey (VEGAS). This first sample of UDG candidates in the Hydra I cluster represents an important step in our project that aims to enlarge the number of confirmed UDGs and, through study of statistically relevant samples, constrain the nature and formation of UDGs. This study presents the main properties of this class of galaxies in the Hydra I cluster. For all UDGs, we analysed the light and colour distribution, and we provide a census of the globular cluster (GC) systems around them. Given the limitations of a reliable GC selection based on two relatively close optical bands only, we find that half of the UDG candidates have a total GC population consistent with zero. Of the other half, two galaxies have a total population larger than zero at 2σ level. We estimate the stellar mass, the total number of GCs, and the GC specific frequency (SN). Most of the candidates span a range of stellar masses of 107 − 108 M⊙. Based on the GC population of these newly discovered UDGs, we conclude that most of these galaxies have a standard or low dark matter content, with a halo mass of ≤1010 M⊙.
GIARPS High-resolution Observations of T Tauri stars (GHOsT)
Authors: Gangi M. , Nisini B. , Antoniucci S. , Giannini T. , Biazzo K. , Alcalá J. M. , Frasca A. , Munari U. , Arkharov A. A. , Harutyunyan A. , Manara C. F. , Rigliaco E. , Vitali F.
Published: August 2020

Context.Disk winds play a fundamental role in the evolution of protoplanetary systems. The complex structure and dynamics can be investigated through the emission of atomic and molecular lines detected in high-resolution optical/IR spectra of young stellar objects. Despite their great importance, however, studies connecting the atomic and molecular components are lacking so far.

Aims.In the framework of the GIARPS High-resolution Observations of T Tauri stars (GHOsT) project, we aim to characterize the atomic and molecular winds in a sample of classical T Tauri stars (CTTs) of the Taurus-Auriga region, focusing on a statistical analysis of the kinematic properties of the [O I] 630 nm and H22.12μm lines and their mutual relationship.

Methods.We analyzed the flux calibrated [O I] 630 nm and H22.12μm lines in a sample of 36 CTTs observed at the Telescopio NazionaleGalileowith the HARPS-N spectrograph (resolving power ofR= 115 000) and with the GIANO spectrograph (R= 50 000). We decomposed the line profiles into different kinematic Gaussian components and focused on the most frequently detected component, the narrow low-velocity (vp< 20 km s−1) component (NLVC).

Results.We found that the H2line is detected in 17 sources (~50% detection rate), and [O I] is detected in all sources but one. The NLV components of the H2and [O I] emission are kinematically linked, with a strong correlation between the peak velocities and the full widths at half maximum of the two lines. Assuming that the line width is dominated by Keplerian broadening, we found that the [O I] NVLC originates from a disk region between 0.05 and 20 au and that of H2in a region from 2 and 20 au. We also found that H2is never detected in sources where [O I] originates in regions below 1 au, as well as in sources of early (~F-G) spectral type with a luminosity >1L⊙. Moreover, in seven sources, both H2and [O I] have clear blueshifted peaks and prominent [O I] high-velocity components. These components have also been detected in sources with no relevant centroid shift. Finally, we did not find any clear correlation betweenvpof the H2and [O I] NVLC and the outer disk inclination. This result is in line with previous studies.

Conclusions.Our results suggest that molecular and neutral atomic emission in disk winds originate from regions that might overlap, and that the survival of molecular winds in disks strongly depends on the gas exposure to the radiation from the central star. The presence of jets does not necessarily affect the kinematics of the low-velocity winds. Our results demonstrate the potential of wide-band high-resolution spectroscopy in linking tracers of different manifestations of the same phenomenon.
KELT-17: a chemically peculiar Am star and a hot-Jupiter planet
Authors: Saffe C. , Miquelarena P. , Alacoria J. , González J. F. , Flores M. , Jaque Arancibia M. , Calvo D. , Jofré E. , Collado A.
Published: August 2020

Context. There is very little information to be found in the literature regarding the detection of planets orbiting chemically peculiar stars.

Aims. Our aim is to determine the detailed chemical composition of the remarkable planet host star KELT-17. This object hosts a hot-Jupiter planet with 1.31 MJup detected by transits, and it is one of the more massive and rapidly rotating planet hosts seen to date. We set out to derive a complete chemical pattern for this star, in order to compare it with those of chemically peculiar stars.

Methods. We carried out a detailed abundance determination in the planet host star KELT-17 via spectral synthesis. Stellar parameters were estimated iteratively by fitting Balmer line profiles and imposing the Fe ionization balance using the SYNTHE program together with plane-parallel ATLAS12 model atmospheres. Specific opacities for an arbitrary composition and microturbulence velocity vmicro were calculated through the opacity sampling (OS) method. The abundances were determined iteratively by fitting synthetic spectra to metallic lines of 16 different chemical species using SYNTHE. The complete chemical pattern of KELT-17 was compared to the recently published average pattern of Am stars. We estimated the stellar radius using two methods: a) comparing the synthetic spectral energy distribution with the available photometric data and the Gaia parallax, and b) using a Bayesian estimation of stellar parameters using stellar isochrones.

Results. We found over-abundances of Ti, Cr, Mn, Fe, Ni, Zn, Sr, Y, Zr, and Ba, together with subsolar values of Ca and Sc. Notably, the chemical pattern agrees with those recently published for Am stars, making KELT-17 the first exoplanet host whose complete chemical pattern is unambiguously identified with this class. The stellar radius derived by two different methods agrees to each other and with those previously obtained in the literature.
Comparative study of the effective parameters on residual stress relaxation in welded aluminum plates under cyclic loading
Authors: Dehkordi Yousef Ghaderi , Anaraki Ali Pourkamali , Shahani Amir Reza
Published: August 2020

The prediction of residual stress relaxation is essential to assess the safety of welded components. This paper aims to study the influence of various effective parameters on residual stress relaxation under cyclic loading. In this regard, a 3D finite element modeling is performed to determine the residual stress in welded aluminum plates. The accuracy of this analysis is verified through experiment. To study the plasticity effect on stress relaxation, two plasticity models are implemented: perfect plasticity and combined isotropic-kinematic hardening. Hence, cyclic plasticity characterization of the material is specified by low cycle fatigue tests. It is found that the perfect plasticity leads to greater stress relaxation. In order to propose an accurate model to compute the residual stress relaxation, the Taguchi L18 array with four 3-level factors and one 6-level is employed. Using statistical analysis, the order of factors based on their effect on stress relaxation is determined as mean stress, stress amplitude, initial residual stress, and number of cycles. In addition, the stress relaxation increases with an increase in mean stress and stress amplitude.
Large deflections of inextensible cantilevers: modeling, theory, and simulation
Authors: Deliyianni Maria , Gudibanda Varun , Howell Jason , Webster Justin T.
Published: August 2020

A recent large deflection cantilever model is considered. The principal nonlinear effects come through the beam’sinextensibility– local arc length preservation – rather than traditional extensible effects attributed to fully restricted boundary conditions. Enforcing inextensibility leads to:nonlinear stiffnessterms, which appear as quasilinear and semilinear effects, as well asnonlinear inertiaeffects, appearing as nonlocal terms that make the beam implicit in the acceleration. In this paper we discuss the derivation of the equations of motionviaHamilton’s principle with a Lagrange multiplier to enforce theeffective inextensibility constraint. We then provide the functional framework for weak and strong solutions before presenting novel results on the existence and uniqueness of strong solutions. A distinguishing feature is that the two types of nonlinear terms present independent challenges: the quasilinear nature of the stiffness forces higher topologies for solutions, while the nonlocal inertia requires the consideration of Kelvin-Voigt type damping to close estimates. Finally, a modal approach is used to produce mathematically-oriented numerical simulations that provide insight into the features and limitations of the inextensible model.
Profil motivationnel des étudiants du premier cycle de la Faculté de médecine de Marrakech
Authors: Hachimi Abdelhamid , Adarmouch Latifa , Ismail Ayman , Hajjine Adam , Amine Mohamed , Bouskraoui Mohammed
Published: August 2020

Contexte :  Dans le domaine de l’éducation, la motivation est identifiée comme un facteur essentiel dans l’engagement, la performance, la persévérance et la réussite. La théorie de l’autodétermination suggère que le comportement humain est régulé par plusieurs classes de motivation. La réalisation de cette étude a été considérée suite à l’intention des décideurs ministériels et pédagogiques de réformer les études médicales. Buts : Identifier les facteurs de motivation pour les études médicales et déterminer les différents types de motivation chez les étudiants du premier cycle. À notre connaissance, il s’agit d’une première étude dans notre contexte marocain. Méthodes : Il s’agit d’une étude transversale, réalisée en 2017 à la Faculté de médecine et de pharmacie de Marrakech. La population cible de notre enquête était les étudiants du premier cycle de médecine générale de l’année universitaire 2016/2017. Un questionnaire anonyme a été élaboré, en se basant sur une revue de la littérature. Il comprenait deux sections : la première a été consacrée pour les données sociodémographiques et la deuxième a été dédiée à la motivation académique à l’aide de l’Échelle de Motivation en Éducation-Études universitaires (EME-U). Résultats : Le taux de réponse était de 80,44 % et 78,55 % pour la première et la deuxième année respectivement. L’âge moyen de nos étudiants était de 19,12 ± 1,02 ans, avec une prédominance féminine dans 65 % des cas. La motivation intrinsèque vient en premier, suivie par la motivation extrinsèque. En comparant les deux sexes, les filles étaient plus altruistes et motivées que les garçons avec une différence statistiquement significative. Conclusion : La motivation intrinsèque était le type de motivation prédominant chez les étudiants. L’autonomie caractérise plus les étudiants du sexe féminin.
Mobiliser les savoirs expérientiels pour la recherche et la formation des professionnels de la santé : concepts et méthodologies
Authors: Aloisio Alves Camila , Prot Bernard , Pacquola Mariachiara , Cavaco Carmen , Breton Hervé , Fernandez Nicolas
Published: August 2020

Problématique :Les approches traditionnelles de recherche en pédagogie des sciences de la santé, axées sur l’évaluation et la mesure, s’arriment difficilement avec l’introduction de la formation des professionnels de la santé axée sur les compétences. L’exploration d’approches de recherche participative et qualitatives s’avère désormais nécessaire pour mieux étudier la formation qui se déroule dans des stages pratiques en milieux cliniques. Nous postulons que le développement des compétences s’appuie en grande partie sur la construction, l’explicitation et la mise en œuvre de savoirs d’expérience.Objectif :Cet article présente un ensemble d’éléments conceptuels et méthodologiques pour les éducateurs dans le domaine de la santé qui cherchent à mobiliser des approches centrées sur la personne, ses expériences et les savoirs qui en découlent afin d’étudier tout en soutenant le développement des compétences professionnelles.Résultats :Pour y parvenir, les auteurs mobilisent un ensemble d’approches de recherche participative pour construire un regard dynamique de l’apprentissage en situation de travail. L’abordage des savoirs expérientiels peut se faire par le biais de la biographisation, qui constitue le dévoilement des savoirs acquis par l’individu au cours de sa vie. Il peut aussi se faire par l’analyse de tâche, qui permet de dégager la construction des savoirs requis pour son accomplissement adéquat. Les deux approches, issues des domaines de la psychologie du travail et des sciences de l’éducation, mènent à une compréhension nuancée du développement des compétences des professionnels.Conclusion :L’aperçu que propose cette contribution sur les savoirs d’expérience comme objet de recherche et leur rôle dans le développement des compétences devrait permettre aux professionnels de la santé d’entamer un projet recherche en pédagogie sous un angle alternatif, alliant dans un même projet la recherche et la formation.
Variable neighborhood search based algorithms for crossdock truck assignment
Authors: Daquin Cécilia , Allaoui Hamid , Goncalves Gilles , Hsu Tienté
Published: August 2020

To operate a cross-dock successfully, an efficient assignment of trucks to docks is one of the key decisions. In this paper, we are interested in the cross-dock assignment of trucks to docks problem, where the number of trucks exceeds the number of docks. The objective is to minimize the cost of transferring goods within the cross-dock while avoiding delivery penalties. This problem being NP-hard, we use Variable Neighborhood Search metaheurisitc (VNS) to solve it approximately. More specifically, we conduct a structured empirical study to compare several VNS configurations and to find which is/are the most effective for this cross-dock problem. In this work, first we analyze the way the search strategy and the neighborhood operators can be combined in a VNS framework according to their efficiency within a local search. Then the best configurations are tested within three VNS variants, namely Basic VNS (BVNS), General VNS (GVNS) using Basic VND (B-VND) and GVNS using Union VND (U-VND) according to the number of used operators and the order of applying these operators. Finally we evaluate the influence of the stopping criterion within these variants. Some significant differences among these configurations are shown and illustrated by conducting the Friedman test.
Paraneoplastische reaktiv perforierende Kollagenose nach transienter akantholytischer Dermatose Grover
Authors: Jung N. , Vogt T. , Müller C. S. L.
Published: August 2020

Wir berichten über einen 90-jährigen Patienten mit Prostata-Karzinom, bei dem initial ein Morbus Grover bestand, welcher einen Wandel der klinischen Morphe hin zu einer erworbenen reaktiv perforierenden Kollagenose im Kontext eines paraneoplastischen Geschehens zeigte. Die detaillierte Pathogenese der transienten akantholytischen Dermatose Grover sowie der reaktiv perforierenden Kollagenose ist derzeit unklar. Während die reaktiv perforierende Kollagenose sporadisch in den paraneoplastischen Kontext gerückt wird, ist der Morbus Grover bisher nicht als paraneoplastische Erscheinung eingeordnet worden. Wir diskutieren die klinischen und histologischen differenzialdiagnostischen Überlegungen und empfehlen auf Basis dieser Beobachtungen bei Auftreten eines auffälligen Morbus Grover an fakultative Paraneoplasien zu denken.
Hyperprolactinemia in Acromegaly is Related to Prolactin Secretion by
Somatolactotroph Tumours
Authors: Van Laethem Delphine , Michotte Alex , Cools Wilfried , Velkeniers Brigitte , Unuane David , Andreescu C. E. , Bravenboer Bert
Published: August 2020

The aim of this study is to assess differences in patient characteristics,
tumour characteristics and hormone levels between acromegalic patients with
and without hyperprolactinemia. 44 patients of the University Hospital of
Brussels, Belgium with acromegaly who were diagnosed between January 2007
and July 2018 were included in this study. Nineteen patients were classified
in the hyperprolactinemia group and 25 patients were classified in the
normoprolactinemia group. No significant differences between acromegalic
patients with and without hyperprolactinemia were found in age at diagnosis,
gender, presence of hyperprolactinemia symptoms, insulin-like growth factor
1, growth hormone and testosterone levels, tumour volume, tumour
invasiveness, immunohistochemistry of growth hormone and prolactin, Ki-67
index and mitotic index. However, for a cut-off of 10% of
prolactin-positive cells, there was a trend towards a higher percentage of
prolactin-positive tumours in hyperprolactinemia patients (p=0.054)
and higher mean prolactin level in case of positive prolactin immunostaining
(p=0.007)). In our study there were no differences in
characteristics between acromegaly patients with hyper- and
normoprolactinemia. An association between the serum prolactin level and the
positivity of prolactin immunohistochemistry of the adenoma tissue was
found. The absence of a difference in tumour volume between patients with
hyper- and normoprolactinemia suggests that the hyperprolactinemia is likely
to be caused by the co-secretion of growth hormone and prolactin by the
tumour. Finally, for the first time, the cut-off of 10% of prolactin
cells was validated for the diagnosis of somatolactotroph tumours in
acromegaly.
Comparative Transcriptome Analysis Reveals Candidate Genes Involved in Isoquinoline Alkaloid Biosynthesis in Stephania tetrandra
Authors: Zhang Yangyang , Kang Yun , Xie Hui , Wang Yaqin , Li Yaoting , Huang Jianming
Published: August 2020

The roots of Stephania tetrandra are used as a traditional Chinese medicine. Isoquinoline alkaloids are considered to be the most important and effective components in this herb,
but little is known about the molecular mechanism underlying their biosynthesis. In this context, this study aimed to reveal candidate genes related to isoquinoline alkaloid
biosynthesis in S. tetrandra. Determination of tetrandrine and fangchinoline in the roots and leaves of S. tetrandra by HPLC showed that the roots had much higher contents
of the two isoquinoline alkaloids than the leaves. Thus, a comparative transcriptome analysis of the two tissues was performed to uncover candidate genes involved in isoquinoline
alkaloid biosynthesis. A total of 71 674 unigenes was obtained and 31 994 of these were assigned putative functions based on BLAST searches against 6 annotation databases. Among the 79
isoquinoline alkaloid-related unigenes, 51 were differentially expressed, with 42 and 9 genes upregulated and downregulated, respectively, when the roots were compared with the leaves.
The upregulated differentially expressed genes were consistent with isoquinoline alkaloid accumulation in roots and thus were deemed key candidate genes for isoquinoline alkaloid
biosynthesis in the roots. Moreover, the expression profiles of 10 isoquinoline alkaloid-related differentially expressed genes between roots and leaves were validated by quantitative
real-time polymerase chain reaction, which indicated that our transcriptome and gene expression profiles were reliable. This study not only provides a valuable genomic resource for
S. tetrandra but also proposes candidate genes involved in isoquinoline alkaloid biosynthesis and transcription factors related to the regulation of isoquinoline alkaloid
biosynthesis. The results lay a foundation for further studies on isoquinoline alkaloid biosynthesis in this medicinal plant.
Sigmoid Sinus Patency following Vestibular Schwannoma Resection via Retrosigmoid versus Translabyrinthine Approach
Authors: Ziegler Andrea , El-Kouri Nadeem , Dymon Zaneta , Serrano David , Bashir Mariah , Anderson Douglas , Leonetti John
Published: August 2020

Introduction The treatment options for acoustic neuromas are observation with serial imaging, stereotactic radiation, or surgical resection. The most common surgical approaches are the translabyrinthine (TL), the retrosigmoid (RS), and the middle cranial fossa. During the TL approach the sigmoid sinus is decompressed with bipolar cautery to allow greater medial exposure. It is unknown if this causes any long-term narrowing or thrombus of the sigmoid sinus.

Methods We performed a retrospective review of patients who underwent acoustic neuroma resection to determine if patients undergoing a TL approach for acoustic neuroma resection develop radiographic evidence of sigmoid sinus stenosis or thrombosis compared with patients undergoing a RS approach.

Results A total of 128 patients were included in this study, 56 patients underwent a TL approach and 72 patients underwent a RS approach. We compared the preoperative and postoperative diameter of the ipsilateral and contralateral sigmoid sinus at proximal, midpoint, and distal locations on magnetic resonance imaging examinations. There was no significant difference between the preoperative and postoperative diameter of the ipsilateral or contralateral sigmoid sinus based on surgical approach.

Conclusion Decompression of the sigmoid sinus during the TL approach does not have a significant postoperative effect on the dural venous sinus patency.
Pediatric Neuromuscular Disorders in Ile-Ife, Nigeria: Pattern and the Challenges with Management
Authors: Olorunmoteni Oluwatosin E. , Kareem Abiodun J. , Ayogu Musa
Published: August 2020

The aim of this study was to describe the presentation pattern and challenges with the management of pediatric neuromuscular disorders (NMDs) in Ile-Ife, Nigeria through retrospective review of their clinical records. We recruited 24 children aged 14 days to 15 years with a male preponderance (male-to-female ratio = 2.4:1). Late presentation was a prominent feature which was highest among children with myopathies with a mean duration of symptoms of 46.5 ± 33.4 months before presentation. Peripheral neuropathy was the most common type of NMDs (63.0%). Among these, injection nerve palsy from the use of wrong site for intramuscular injections was the most common (60.0%). Nonavailability of electrophysiologic and genetic testing as well as appropriate medications was the major challenges. Acquired NMDs are common in our setting. There is a need to improve preventive measures of acquired NMDs and early diagnosis of the inherited types.
Shortcomings in Design and Analysis of Clinical Studies on Bleeding and Thrombosis in Patients with Cirrhosis
Authors: Northup Patrick , Davis Jessica
Published: August 2020

Significant gains have been made in our understanding of bleeding and thrombosis in patients with liver disease in recent years, with concurrent exponential growth in the scientific literature published in this realm. Clinical studies of this population are challenging for multiple reasons including some hurdles unique to this population. Cirrhosis patients as a whole, especially those with decompensated cirrhosis, are a high-risk and heterogeneous population prone to serious adverse events. Outcomes of bleeding and thrombosis are relatively rare and lack standardized, validated definitions. Standard practices for clinical care have evolved rapidly and rendered some control data uninformative. We aim to highlight these challenges and make recommendations for best practices for future study design and implementation. Multidisciplinary collaboration with proceduralists, careful study design including attention to validated clinically relevant outcomes, and aggressive pursuit of all funding streams will be key to continued scientific success in this burgeoning field.
Incidence of Bleeding and Thrombosis in Patients with Liver Disease
Authors: Roberts Lara N. , Bernal William
Published: August 2020

Historically, liver disease has been associated with a bleeding tendency. Global hemostatic assays have demonstrated that hemostasis is overall rebalanced, in both acute liver failure and chronic liver disease. It is now recognized that many bleeding events in chronic liver disease are mediated by portal hypertension rather than an underlying hemostatic defect. This is acknowledged in recent guidelines, which recommend against coagulation testing prior to low risk procedures in this patient group, with avoidance also of attempts at correction of prolonged coagulation times. Over time, the incidence of bleeding events has decreased in both chronic liver disease and acute liver failure, with improved supportive care, targeted treatments for underlying cause of liver disease, and the advent of liver transplantation. Concurrently, there has been increased recognition of the risk of thrombosis in chronic liver disease, with a predilection for the splanchnic vasculature. This review describes the incidence of bleeding and thrombosis in chronic liver disease and acute liver failure, including the periprocedural and liver transplantation setting.
Three-Dimensional Finite Element Analysis to Evaluate Stress Distribution in Tooth and Implant-Supported Fixed Partial Denture–An In Vitro Study
Authors: Jain Himani , Kalra Tarun , Kumar Manjit , Bansal Ajay , Jain Deepti
Published: August 2020

Introduction This study was undertaken to assess the influence of different superstructure materials, when subjected to occlusal loading, on the pattern of stress distribution in tooth-supported, implant-supported, and tooth implant-supported fixed partial prostheses, using the finite element analysis with a comparative viewpoint.

Materials and Methods The geometric models of implant and mandibular bone were generated. Three models were created in accordance with the need of the study. The first model was given a tooth-supported fixed partial prosthesis. The second model was given tooth implant-supported fixed partial prosthesis, and the third model was given implant-supported fixed partial prosthesis. Forces of 100 N and 50 N were applied axially and buccolingually, respectively.

Results The present study compared the stresses arising in the natural tooth, implant, and the whole prostheses under simulated axial and buccolingual loading of three types of fixed partial dentures, namely, tooth-supported, tooth implant-supported, and implant-supported fixed partial dental prostheses using three different types of materials.

Conclusion The pattern of stress distribution did not appear to be significantly affected by the type of prosthesis materials in all models. The maximum stress concentrations were found in the alveolar bone around the neck of the teeth and implants.
COVID-19 Pandemic and the Mental Health of Health Care Workers: Awareness to Action
Authors: Rajhans Pallavi , Deb Koushik Sinha , Chadda Rakesh Kumar
Published: August 2020

The enormity of the coronavirus disease-2019 (COVID-19) pandemic has overwhelmed most health services and has placed health care service providers under unprecedented stress. The rapidity of spread, uncertain clinical course, and unavailability of effective treatment make clinical decisions cognitively demanding. Extended work hours inside uncomfortable protective gears, improper hydration, with conflictual health systems and patients at work; and social stigma and isolation after it ends, have created an unending downward spiral of mental health in care providers. Care providers are at increased risk of developing mental health problems in form of burnout, stress reactions, anxiety, depression, and post trauma stress. Concerted strategies for managing the mental health of care providers are urgently needed at individual and systems level. A plethora of strategies, developed from previous experience of crisis management, need to be made available to care providers through accessible mediums of delivery. This paper explores the mental health problems encountered by health care personnel and examines various strategies which need to be implemented to manage them.
The Psychological Experience of Obstetric Patients and Health Care Workers after Implementation of Universal SARS-CoV-2 Testing
Authors: Bender Whitney R. , Srinivas Sindhu , Coutifaris Paulina , Acker Alexandra , Hirshberg Adi
Published: August 2020

Objective This study was aimed to describe the hospitalization and early postpartum psychological experience for asymptomatic obstetric patients tested for severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) as part of a universal testing program and report the impact of this program on labor and delivery health care workers' job satisfaction and workplace anxiety.

Study Design This is a cohort study of asymptomatic pregnant women who underwent SARS-CoV-2 testing between April 13, 2020 and April 26, 2020. Semistructured interviews were conducted via telephone at 1 and 2 weeks posthospitalization to assess maternal mental health. Depression screening was conducted using the patient health questionnaire-2 (PHQ-2). An online survey of labor and delivery health care workers assessed job satisfaction and job-related anxiety before and during the novel coronavirus disease 2019 (COVID-19) pandemic, as well as employees' subjective experience with universal testing. Patient and employee responses were analyzed for recurring themes.

Results A total of 318 asymptomatic women underwent SARS-CoV-2 testing during this 2-week period. Six of the eight women (75%) who tested positive reported negative in-hospital experiences secondary to perceived lack of provider and partner support and neonatal separation after birth. Among the 310 women who tested negative, 34.4% of multiparous women reported increased postpartum anxiety compared with their prior deliveries due to concerns about infectious exposure in the hospital and lack of social support. Only 27.6% of women, tested negative, found their test result to be reassuring. Job satisfaction and job-related anxiety among health care workers were negatively affected. Universal testing was viewed favorably by the majority of health care workers despite concerns about delays or alterations in patient care and maternal and neonatal separation.

Conclusion Universal testing for SARS-CoV-2 in obstetric units has mixed effects on maternal mental health but is viewed favorably by labor and delivery employees. Ongoing evaluation of new testing protocols is paramount to balance staff and patient safety with quality and equality of care.

Key Points
Group singing as a resource for the development of a healthy public: a study of adult group singing
Authors: Camlin David A. , Daffern Helena , Zeserson Katherine
Published: August 2020

A growing body of evidence points to a wide range of benefits arising from participation in group singing. Group singing requires participants to engage with each other in a simultaneous musical dialogue in a pluralistic and emergent context, creating a coherent cultural expression through the reflexive negotiation of (musical) meaning manifest in the collective power of the human voice. As such, group singing might be taken—both literally and figuratively—as a potent form of ‘healthy public’, creating an ‘ideal’ community, which participants can subsequently mobilise as a positive resource for everyday life. The experiences of a group of singers (n = 78) who had participated in an outdoor singing project were collected and analysed using a three-layer research design consisting of: distributed data generation and interpretation, considered against comparative data from other singing groups (n = 88); a focus group workshop (n = 11); an unstructured interview (n = 2). The study confirmed an expected perception of the social bonding effect of group singing, highlighting affordances for interpersonal attunement and attachment alongside a powerful individual sense of feeling ‘uplifted’. This study presents a novel perspective on group singing, highlighting the importance of participant experience as a means of understanding music as a holistic and complex adaptive system. It validates findings about group singing from previous studies—in particular the stability of the social bonding effect as a less variant characteristic in the face of environmental and other situational influences, alongside its capacity for mental health recovery. It establishes a subjective sociocultural and musical understanding of group singing, by expanding on these findings to centralise the importance of individual experience, and the consciousness of that experience as descriptive and reflective self-awareness. The ways in which participants describe and discuss their experiences of group singing and its benefits points to a complex interdependence between a number of musical, neurobiological and psychosocial mechanisms, which might be independently and objectively analysed. An emerging theory is that at least some of the potency of group singing is as a resource where people can rehearse and perform ‘healthy’ relationships, further emphasising its potential as a resource for healthy publics.
Non-perturbative dynamics of the operator size distribution in the Sachdev–Ye–Kitaev model
Authors: Lucas Andrew
Published: August 2020

We prove non-perturbative bounds on the time evolution of the probability distribution of operator size in the q-local Sachdev–Ye–Kitaev model with N fermions for any even integer q > 2 and any positive even integer N > 2q. If the couplings in the Hamiltonian are independent and identically distributed Rademacher random variables, the infinite temperature many-body Lyapunov exponent is almost surely finite as N → ∞. In the limit q → ∞, N → ∞, and q6+δ/N → 0, the shape of the size distribution of a growing fermion, obtained by leading order perturbation calculations in 1/N and 1/q, is similar to a distribution that locally saturates our constraints. Our proof is not based on Feynman diagram resummation; instead, we note that the operator size distribution obeys a continuous time quantum walk with bounded transition rates to which we apply concentration bounds from classical probability theory.
Effects of different active control strategies on combustion instability decay time, actuator voltage, and damping ratio
Authors: Tao Chengfei , Zhou Hao
Published: August 2020

This article numerically investigates the effects of different control strategies on combustion instability (also known as thermoacoustic instability) based on a lean-premixed combustor. Combustion instability occurs in the combustor with a sound pressure level of 51 Pa and an oscillation frequency of 271 Hz. Experimental results and the geometric data of the unstable combustor were modeled for thermoacoustic instability active control. Four types of controllers were used, and differences among control strategies were explored by comparing the “damping ratio,” “maximum actuator voltage,” and “decay time” of the active control. Results indicate that the nonlinear controller can promptly and effectively suppress thermoacoustic instability, but its actuator overshoots after triggering. The regular linear controller could not effectively suppress thermoacoustic instability. Its damping ratio was 60% compared to the damping ratio of the other controllers, and its decay time was longer than those of the other three controllers. The variation tendency of the actuator output voltage was nearly similar to that of sound pressure. The phase-shift controller had a minimum “maximum actuator voltage” of 25.6 mV under limit cycle states. The damping characteristics of the four controllers may have depended on decay time. The nonlinear controller had a minimal decay time of 0.052 s under limit cycle states. This study compared the effects of different active controllers on combustion instability and may contribute to preventing thermoacoustic instabilities in gas turbines.
Tuning of structural and dielectric properties of Gd2O3 grown on Si(001)
Authors: Gribisch P. , Fissel A.
Published: August 2020

The structural and dielectric properties of gadolinium oxide (Gd2O3) grown on Si(001) depending on the epitaxial growth conditions were investigated. Gd2O3 layers were grown at temperatures between 250°C and 400°C with an oxygen partial pressure between 2×10−7mbar and 5×10−7mbar. The crystal structure of the Gd2O3 turns out to be monoclinic with rotational domains as revealed by x-ray diffraction measurements and transmission electron microscopy (TEM) investigations. The dielectric properties can be tuned with growth temperature, forming gas annealing, and an increase in oxygen partial pressure. Furthermore, the dielectric constant was found to increase with the layer thickness. This can be interpreted in terms of the presence of a two layer stack consisting an interfacial quasi-amorphous and monoclinic Gd2O3 on top, as confirmed by TEM. The value of around 33 was extracted for the dielectric constant of monoclinic Gd2O3, which is much higher than for cubic Gd2O3. The best Gd2O3 layers grown at 400°C and pO2=5×10−7mbar exhibit also a characteristic leakage current value J(Vfb−1V) for a CET value of around 2 nm in the range of a few nA/cm2, which enable the applicability in electronic devices.
Learning reaction coordinates via cross-entropy minimization: Application to alanine dipeptide
Authors: Mori Yusuke , Okazaki Kei-ichi , Mori Toshifumi , Kim Kang , Matubayasi Nobuyuki
Published: August 2020

We propose a cross-entropy minimization method for finding the reaction coordinate from a large number of collective variables in complex molecular systems. This method is an extension of the likelihood maximization approach describing the committor function with a sigmoid. By design, the reaction coordinate as a function of various collective variables is optimized such that the distribution of the committor pB* values generated from molecular dynamics simulations can be described in a sigmoidal manner. We also introduce the L2-norm regularization used in the machine learning field to prevent overfitting when the number of considered collective variables is large. The current method is applied to study the isomerization of alanine dipeptide in vacuum, where 45 dihedral angles are used as candidate variables. The regularization parameter is determined by cross-validation using training and test datasets. It is demonstrated that the optimal reaction coordinate involves important dihedral angles, which are consistent with the previously reported results. Furthermore, the points with pB*∼0.5 clearly indicate a separatrix distinguishing reactant and product states on the potential of mean force using the extracted dihedral angles.
Anisotropic shaped Fe3O4 nanoparticles: Microwave-assisted thermal decomposition synthesis and their electromagnetic properties
Authors: Liang Yi-Jun , Zhang Ling , Chen Minmin , Fan Lixia , Liao Wanqin , Xun Yang , Fu Li , Liu Jing , Liu Fang , Yang Anping
Published: August 2020

Investigating the electromagnetic properties of magnetite nanoparticles (Fe3O4 NPs) is beneficial for expanding their biomedical applications, especially in tumor hyperthermia. In this study, monodisperse Fe3O4 NPs of various shapes (i.e., quadrilateral-like, hexagon-like, rod-like, and triangle-like) were successfully prepared by a microwave-assisted thermal decomposition approach. The magnetic properties and inductive heating performance, as well as electromagnetic properties were analyzed systematically. The results showed that quadrilateral-like Fe3O4 NPs possessed excellent magneto-thermal effects and maximum specific absorption rate values of 226.4 W/g and 1409.6 W/g (390 kHz and 780 kHz, 12 A). Moreover, a sample filled with 70 wt. % quadrilateral-like NPs in paraffin showed a minimum reflection loss (RL) value of −33.4 dB, along with a broad absorption bandwidth of RL < −10 dB covering 2 GHz–18 GHz. The high magnetic loss may be derived from the eddy current loss and natural resonance. This study would deepen the understanding of microwave absorption properties of Fe3O4 NPs and enrich their microwave applications based on shape anisotropy.
κ-Deformed quantum and classical mechanics for a system with position-dependent effective mass
Authors: da Costa Bruno G. , Gomez Ignacio S. , Portesi Mariela
Published: August 2020

We present the quantum and classical mechanics formalisms for a particle with a position-dependent mass in the context of a deformed algebraic structure (named κ-algebra), motivated by the Kappa-statistics. From this structure, we obtain deformed versions of the position and momentum operators, which allow us to define a point canonical transformation that maps a particle with a constant mass in a deformed space into a particle with a position-dependent mass in the standard space. We illustrate the formalism with a particle confined in an infinite potential well and the Mathews–Lakshmanan oscillator, exhibiting uncertainty relations depending on the deformation.
Nonlinear forced vibration analysis of composite beam combined with DQFEM and IHB
Authors: Ri Kwangchol , Han Poknam , Kim Inchol , Kim Wonchol , Cha Hyonbok
Published: August 2020

In this paper, a forced vibration model of composite beams under the action of periodic excitation force considering geometric nonlinearity is proposed. For the strain–displacement relationship, Timoshenko beam theory is used, and the element and system matrices are developed using the differential quadrature finite element method. Each node has 3 degrees of freedom. The incremental harmonic balance method is used to solve the nonlinear forced vibration equation. In order to prove the validity of the proposed model, the solution of the Duffing equation is calculated using the analytical method and the proposed method. Next, linear forced vibration analysis of the beam made of isotropic material is performed and compared with the result of ABAQUS. The results are very close. Based on these comparisons, nonlinear vibration phenomena of composite beams are studied under the action of periodic forces.