bluuebunny/crossref_metadata_2025 huggingface dataset:
Near‐infrared‐to‐vacuum‐ultraviolet high‐harmonic Raman and plasma emission spectroscopy with ultrashort mid‐infrared laser pulses
Authors: Mitrofanov Alexander V. , Rozhko Mikhail V. , Sidorov‐Biryukov Dmitry A. , Voronin Alexander A. , Fedotov Andrei B. , Zheltikov Aleksei M.
Published: October 2021

We demonstrate a new modality of ultrafast laser spectroscopy based on high‐harmonic‐driven stimulated Raman scattering (hi‐SRS) and incoherent laser‐plasma emission (iLPE). The spectra of high‐order harmonics driven by sub‐100‐fs pulses in the mid‐infrared are shown to display well‐resolved Raman‐gain, Raman‐loss, and iLPE features, enabling a chemically specific, single‐beam, single‐shot spectroscopy of gases and plasmas within a spectral range stretching from the near‐infrared to vacuum ultraviolet. We present a theoretical framework based on a suitably adapted nonlinear evolution equation that enables a closed‐form description of hi‐SRS as an ultrafast nonlinear‐optical phenomenon. We show that the content of hi‐SRS as a physical process and as a method of spectroscopy goes well beyond standard SRS, offering a powerful resource for spectroscopy, remote sensing, and ultrafast optical science. Standing out as particularly relevant for nitrogen‐containing gas systems, including atmospheric air, is a multimodal spectroscopic probe that combines ultrafast hi‐SRS via the second positive system of molecular nitrogen with iLPE via the γ band of nitrogen monoxide.
Selective Fetal Growth Restriction Type III
Authors: Chmait Sami R. , Monson Martha A. , Korst Lisa M. , Llanes Arlyn , Chon Andrew H.
Published: October 2021

Objectives

Per a recent expert definition, diagnosis of selective fetal growth restriction (sFGR) in monochorionic diamniotic twins is based on an estimated fetal weight (EFW) <3% as sole criterion and/or combinations of 4 contributory criteria (1 twin EFW <10%; 1 twin abdominal circumference <10%; EFW discordance ≥25%; and smaller twin umbilical artery [UA] pulsatility index >95th percentile). We assessed these criteria in sFGR Type III (intermittent absent or reversed end‐diastolic flow of the UA [iAREDF]) patients to test whether meeting the more stringent parameters of the consensus definition had worse outcomes, that is, progression to sFGR Type II (persistent AREDF) or twin‐twin transfusion syndrome; or secondarily, decreased dual survivorship.

Methods

This was a retrospective study of referred sFGR Type III patients (2006–2017). Patients were retrospectively categorized using consensus criteria for 2 comparisons: 1) EFW <3% versus remaining cohort; 2) EFW <3% or met all 4 contributory criteria versus remaining cohort.

Results

Forty‐eight patients were studied. Comparison 1: EFW <3% patients (58.3%) were not more likely to demonstrate disease progression (46.4% versus 65.0%, P = .2489) or worse dual survivorship (78.6% versus 85.0%, P = .7161). Comparison 2: EFW <3% or met all 4 contributory criteria (75.0%) patients were not more likely than the others to demonstrate progression (44.4% versus 83.3%, P = .0235) or worse dual survivorship (80.6% versus 83.3%, P = 1.0000).

Conclusions

In a referred cohort of sFGR Type III patients, there was no evidence that meeting more stringent parameters of the consensus definition was associated with disease progression or dual survivorship.
Noninvasive Respiratory Support as an Alternative to Tracheostomy in Severe Laryngomalacia
Authors: Veroul Elina , Amaddeo Alessandro , Leboulanger Nicolas , Gelin Matthieu , Denoyelle Françoise , Thierry Briac , Fauroux Brigitte , Luscan Romain
Published: October 2021

Objectives/Hypothesis

To analyze the role of noninvasive respiratory support (NRS) as an alternative to tracheostomy in the management of severe laryngomalacia.

Study Design

We conducted a monocentric retrospective study in a tertiary pediatric care center.

Methods

All children under the age of 3 years with severe laryngomalacia, treated between January 2014 and December 2019, were included. Patient demographics, medical history, nutrition, surgery, NRS, and outcome were reviewed. Predictors for NRS were analyzed.

Results

One hundred and eighty‐eight patients were included. Mean age was 4 ± 5 months and mean weight was 4,925 ± 1,933 g. An endoscopic bilateral supraglottoplasty was performed in 183 (97%) patients and successful in 159 (87%). NRS was initiated in 29 (15%) patients at a mean age of 3 ± 2 months (1–11 months): 15 (52%) patients were treated with NRS after surgical failure, 9 (31%) were treated with NRS initiated prior to surgery because of abnormal overnight gas exchange, and 5 (17%) were treated exclusively with NRS due to comorbidities contraindicating an endoscopic procedure. NRS was successfully performed in all patients with a mean duration of 6 ± 11 months. No patient required a tracheostomy. Univariate analysis identified the following predictors of NRS: neonatal respiratory distress (P = .003), neurological comorbidity (P < .001), associated laryngeal abnormality (P < .001), cardiac surgery (P = .039), surgical endoscopic revision (P = .007), and nutritional support (P < .001).

Conclusion

NRS is a safe procedure, which may avoid a tracheostomy in severe laryngomalacia, in particular, in case of endoscopic surgery failure, respiratory failure before surgery, and/or severe co‐morbidity.

Level of Evidence

3 Laryngoscope, 132:1861–1868, 2022
Succession of aquatic and littoral vegetation in disused sandpits
Authors: Müllerová Anna , Řehounková Klára , Prach Karel
Published: October 2021

Vegetation succession in aquatic and littoral environments has received much less attention compared to terrestrial habitats. We sampled differently aged successional stages in 63 sandpits across the Czech Republic, Central Europe. They ranged in age since abandonment from 1 to 64 years. The chronosequence approach was adopted. Besides species identity itself, basic life‐history species traits were considered to describe the succession. Based on the location (elevation) of plots, two geographical regions were delimited based on temperature and precipitation. Alongside the vegetation data, several environmental variables were recorded: age, water depth, substratum type (i.e., proportion of sand, clay, gravel and organic material), pH, conductivity, elevation and additional disturbances. Altogether, 249 vascular plant species were determined. Individual successional series in aquatic and littoral habitats differed between the altitudinal regions. As generally expected, water table was one of the main driving factors alongside age and water conductivity. Moreover, the vegetation pattern was significantly affected by substrate composition and pH. The species composition at aquatic sites was most likely mainly driven by the accumulation of organic material. Hydrophytes dominated throughout these sites. In littoral vegetation, several distinct groups of life forms could be distinguished along the successional gradient. The young sites typically included stress‐tolerant therophytes and hemicryptophytes. With age, woody species started to dominate at littoral sites at higher elevations, while perennial graminoids dominated at lowland sites. Spontaneous succession at aquatic and littoral sites leads to valuable semi‐natural stages and is recommended as a passive restoration option in disused sandpits.
Ultra‐Sensitive and Highly Stretchable Strain Sensors for Monitoring of Human Physiology
Authors: Verma Ravi Prakash , Sahu Prateekshya Suman , Rathod Mitesh , Mohapatra Soumya Sanjeeb , Lee Junghoon , Saha Biswajit
Published: October 2021

The flexible strain sensors have potential applications in advanced electronics, health monitoring systems, wearable sensors, robotics, and human–machine interfaces. The development of highly sensitive, stretchable, and durable strain sensors is a challenging task for researchers. However, the sensors with a detection range from large strain to minute deflection are imperative for human‐interactive applications. This work has demonstrated a facile method of sensor fabrication, which use reduced graphene oxide (rGO) as sensing material and silicone sealant as a flexible substrate. Few‐layer rGO is synthesized by electrochemical exfoliation of pencil lead. The fabricated sensors have a gauge factor higher than 4000 and durability longer than 1600 cycles at 100% strain. At the same time, developed strain sensors exhibit detection capability over a wide range of strain (0–120%), which is an essential requirement of wearable sensors. To the best of the authors’ knowledge, fewer works have reported strain sensors that have ultra‐high gauge factor (≥4000) in combination with high stretchability (>100%). Utilizing the ultra‐sensitivity and sub‐second response time of the rGO‐sealants, these wearable sensors are used to monitor physical activities, heartbeats, and finger touches.
Discussion on the controllability results for fractional neutral impulsive Atangana–Baleanu delay integro‐differential systems
Authors: Kavitha Williams W. , Vijayakumar V.
Published: October 2021

This manuscript is mainly focusing on the existence of Atangana–Baleanu semilinear fractional integro‐differential equations with noninstantaneous impulses. The outcomes are proved via Darbo's fixed point theorem and their results when combined with the properties of the measure of noncompactness. Finally, we present a theoretical application to support the validity of the study.
An equilibrium‐based formulation with nonlinear configuration dependent interpolation for geometrically exact 3D beams
Authors: Santana Murillo V. B. , Sansour Carlo , Hjiaj Mohammed , Somja Hugues
Published: October 2021

This article describes a novel equilibrium‐based geometrically exact beam finite element formulation. First, the spatial position and rotation fields are interpolated by nonlinear configuration‐dependent functions that enforce constant strains along the element axis, completely eliminating locking phenomena. Then, the resulting kinematic fields are used to interpolate the spatial sections force and moment fields in order to fulfill equilibrium exactly in the deformed configuration. The internal variables are explicitly solved at the element level and closed‐form expressions for the internal force vector and tangent stiffness matrix are obtained, allowing for explicit computation, without numerical integration. The objectivity and absence of locking are verified and some important numerical and theoretical aspects leading to a computationally efficient strategy are highlighted and discussed. The proposed formulation is successfully tested in several numerical application examples.
Nurse and case manager views on improving access and use of healthcare for adults living in permanent supportive housing
Authors: Schneiderman Janet U. , Nedjat‐Haiem Frances , Rivera Dean , Pérez Jolles Mónica
Published: October 2021

Housing is one of the social determinants of health, and homelessness is associated with health inequalities including increased morbidity and decreased life expectancy. Services to improve access to and use of primary healthcare are provided to formerly homeless individuals (hereafter residents) who live in permanent supportive housing (PSH). Residents do not always utilize services, nor receive adequate healthcare, and often have poor health outcomes. The study aims were to explore nurse and case manager (hereafter participants) views on the challenges of providing healthcare to residents, and strategies to address challenges. This descriptive, qualitative study used thematic analysis. Five nurses and eight case managers working with residents of PSH agencies were interviewed using semistructured interviews. Five main themes emerged. The first theme of context of healthcare use included how the residents' history of homelessness, trauma, and survival affected using services. The second theme was how aspects of relationships (communication issues and mistrust) were barriers to care. The third theme was how residents' health issues (physical chronic diseases, mental health, and substance dependency) affected care. Community level barriers (insurance, financial hardship, and transportation) was the fourth theme. The final theme highlighted recommendations to improve access and use of healthcare by building rapport, addressing mistrust, and using effective communication techniques. Participants noted that barriers to healthcare use were often influenced by residents' previous homeless experience. Nurses noted that chronic physical health issues were problematic for residents. Participants expressed the need to take time to form an authentic relationship to increase trust with residents.
Long‐term antagonism and allosteric regulation of mu opioid receptors by the novel ligand, methocinnamox
Authors: Zamora Joshua C. , Smith Hudson R. , Jennings Elaine M. , Chavera Teresa S. , Kotipalli Varun , Jay Aleasha , Husbands Stephen M. , Disney Alex , Berg Kelly A. , Clarke William P.
Published: October 2021

Opioid overdose is a leading cause of death in the United States. The only treatment available currently is the competitive antagonist, naloxone (Narcan®). Although naloxone is very effective and has saved many lives, as a competitive antagonist it has limitations. Due to the short half‐life of naloxone, renarcotization can occur if the ingested opioid agonist remains in the body longer. Moreover, because antagonism by naloxone is surmountable, renarcotization can also occur in the presence of naloxone if a relatively larger dose of opioid agonist is taken. In such circumstances, a long‐lasting, non‐surmountable antagonist would offer an improvement in overdose treatment. Methocinnamox (MCAM) has been reported to have a long duration of antagonist action at mu opioid receptors in vivo. In HEK cells expressing the human mu opioid receptor, MCAM antagonism of mu agonist‐inhibition of cAMP production was time‐dependent, non‐surmountable and non‐reversible, consistent with (pseudo)‐irreversible binding. In vivo, MCAM injected locally into the rat hindpaw antagonized mu agonist‐mediated inhibition of thermal allodynia for up to 96 h. By contrast, antagonism by MCAM of delta or kappa agonists in HEK cells and in vivo was consistent with simple competitive antagonism. Surprisingly, MCAM also shifted the concentration‐response curves of mu agonists in HEK cells in the absence of receptor reserve in a ligand‐dependent manner. The shift in the [D‐Ala2,N‐MePhe4,Gly‐ol5]‐enkephalin (DAMGO) concentration‐response curve by MCAM was insensitive to naloxone, suggesting that in addition to (pseudo)‐irreversible orthosteric antagonism, MCAM acts allosterically to alter the affinity and/or intrinsic efficacy of mu agonists.
Secondary structures, dynamics, and DNA binding of the homeodomain of human SIX1
Authors: Li Yan , Ng Elizabeth YiHui , Loh Ying Ru , Gea Chong Yu , Huang Qiwei , Li Qingxin , Kang CongBao
Published: October 2021

Human sine oculis homeobox homolog (SIX) 1 contains a homeodomain (HD), which is important for binding to DNA. In this study, we carried out structural studies on the HD of human SIX1 using nuclear magnetic resonance (NMR) spectroscopy. Its secondary structures and dynamics in solution were explored. HD is well‐structured in solution, and our study shows that it contains three α‐helices. Dynamics study indicates that the N‐ and C‐terminal residues of HD are flexible in solution. HD of human SIX1 exhibits molecular interactions with a short double‐strand DNA sequence evidenced by the 1H‐15N‐heteronuclear single quantum correlation (HSQC) and 19F‐NMR experiments. Our current study provides structural information for HD of human SIX1. Further studies indicate that this construct can be utilized to study SIX1 and DNA interactions.
Application of hypergraph theory in the analysis of the failure propagation and diffusion behaviour of machining centre
Authors: Mu Liming , Zhang Yingzhi , Wang Xiaofeng , Zhou Yutong
Published: October 2021

To improve the rationality of failure diagnosis, this research uses hypergraph theory as basis in proposing a method of analysing failure propagation behaviour to study the failure propagation mechanism from the system perspective. A hierarchical structure model is constructed by failure correlation analysis, matrix transformation and decomposition. The probability of failure is determined by considering the influence of multiple truncation data. On this basis, hypergraph theory is used to calculate the one‐step and cumulative coefficient of failure propagation and diffusion. The influence degree of failure is calculated by integrating the edge betweenness. Using the influence degree of failure as an indicator, failure propagation and diffusion behaviour are analysed, and critical failure nodes and paths are identified. Lastly, a machining centre is used as an example for specific application. The results are compared with the ranking results of critical failure propagation paths determined by other methods, and the effectiveness of the proposed method is verified.
The fate of the City of Mutare's urban water supply as changing climate impacts on its source in the Pungwe sub‐catchment
Authors: Gumbo Anesu D. , Kapangaziwiri Evison
Published: October 2021

Sustaining a steady supply of water to urban communities is of importance in a period that is characterised by rapid urban population growth, a global pandemic, and a changing climate that threatens the availability of the resource from its sources. Water supply to the City of Mutare is from three sources, Small Bridge Dam, Odzani, and the Pungwe River. The Pungwe source provides better quality water resources equivalent to the combined quantity supplied by the other two. It becomes an important source for the city, but climate change threatens the availability of water resources in the southern African region. Thus, it is imperative to quantitatively assess the impacts of a changing climate on water resources to enable the development of sustainable management alternatives. Using two carbon emission scenarios Representative Concentration Pathways (RCPs) 4.5 and 8.5, the study assesses the future availability of water resources from the Pungwe River to the City of Mutare using the Pitman hydrological model applied in an uncertainty framework. Available historical streamflow observations at gauging station F14 indicate a Q95 flow of about 2 Mm3/year. Projected future water resources at the end of the 21st century show a slight increase of up to 2.38% under the low carbon emission scenario (RCP4.5) and a decrease of up to 9.73%under the high carbon emission scenario (RCP8.5). These model‐generated results are useful to water managers to plan for catchment management strategies that would ensure continuous urban water supply, and the identification and development of possible future alternative water sources.
Mapping soil depth in southern pampas Argentina using ancillary data and statistical learning
Authors: Peralta Nahuel Raul , Alesso Carlos Agustín , Costa Jose Luis , Martin Nicolás Federico
Published: October 2021

Restrictive layers such as hardpans limit the soil water and nutrients available for crops. In the southern Argentinean pampas, petrocalcic hardpans are found at variable depth within the field. Mapping the spatial distribution of depth to the petrocalcic hardpan is important for proper land evaluation, use, and management. Intensive grid sampling and spatial interpolation are labor‐intensive and time‐consuming mapping approaches for this soil property. In addition, the spatial distribution of this property is often difficult for interpolation techniques such as kriging. This study's objective was to evaluate the potential of soil electrical conductivity (ECa) and terrain attributes to map within‐field spatial variation of soil depth using statistical learning techniques. Soil depth measurements up to 1‐m depth were taken in eight fields at spatial sampling density ranging from 2 to 12 points ha–1. Spatially dense data of elevation, terrain attributes, and ECa were migrated to soil depth sampling points and also spatially aggregated to include spatial information into the featured space. Then, random forest regression models were used to predict soil depth from colocated ECa and terrain data. Models were cross‐validated using a k‐fold approach using entire fields as folds. The overall model (using all data) resulted in out‐of‐the bag R2 and RMSE of .66 and 22.8 cm respectively. Shallow (0–30 cm) and deep (0–90 cm) ECa values were the most important variables, accounting for variability at different ranges, but the importance varied between the soil types. These results suggested that field‐scale ECa data and terrain attributes have potential to predict soil depth to hardpan. Further research is needed to improve the generalization of these models and improve the representation of spatial effects in order to implement site‐specific management based on soil depth maps.
Rationalizing Surface Electronic Configuration of Ni–Fe LDO by Introducing Cationic Nickel Vacancies as Highly Efficient Electrocatalysts for Lithium–Oxygen Batteries
Authors: Ren Longfei , Zheng Ruixin , Zhou Bo , Xu Haoyang , Li Runjing , Zhao Chuan , Wen Xiaojuan , Zeng Ting , Shu Chaozhu
Published: October 2021

Cationic defect engineering is an effective strategy to optimize the electronic structure of active sites and boost the oxygen electrode reactions in lithium–oxygen batteries (LOBs). Herein, Ni–Fe layered double oxides enriched with cationic nickel vacancies (Ni–Fe LDO‐VNi) are first designed and studied as the electrocatalysts for LOBs. Based on the density functional theory calculation, the existence of nickel vacancy in Ni–Fe LDO‐VNi significantly improves its intrinsic affinity toward intermediates, thereby fundamentally optimizing the formation and decomposition pathway of Li2O2. In addition, the number of eg electrons on each nickel site is 1.19 for Ni–Fe LDO‐VNi, which is much closer to 1 than 1.49 for Ni–Fe LDO. The near‐unity occupation of eg orbital enhances the covalency of transition metal–oxygen bonds and thus improves the electrocatalytic activity of Ni–Fe LDO‐VNi toward oxygen electrode reactions. The experimental results show that the LOBs with Ni–Fe LDO‐VNi electrode deliver low overpotentials of 0.11/0.29 V during the oxygen reduction reaction/oxygen evolution reaction, respectively, large specific capacities of 13 933 mA h g−1 and superior cycling stability of over 826 h. This study provides a novel approach to optimize the electrocatalytic activity of LDO through reasonable defect engineering.
ZaligVinder: A generic test framework for string solvers
Authors: Kulczynski Mitja , Manea Florin , Nowotka Dirk , Poulsen Danny Bøgsted
Published: October 2021

The increased interest in string solving in the recent years has made it very hard to identify the right tool to address a particular user's purpose. Firstly, there is a multitude of string solvers, each addressing essentially some subset of the general problem. Generally, the addressed fragments are relevant and well motivated, but the lack of comparisons between the existing tools on an equal set of benchmarks cannot go unnoticed, especially as a common framework to compare solvers seems to be missing. In this paper, we gather a set of relevant benchmarks and introduce our new benchmarking framework to address this purpose.
Software refactoring side effects
Authors: AbuHassan Amjad , Alshayeb Mohammad , Ghouti Lahouari
Published: October 2021

Software refactoring solutions aim at mitigating the negative effects of code and design smells on the overall software quality. Many efforts have been exerted to improve the software refactoring process. However, most of these efforts, despite their contributions, overlooked the side effects of the identified refactoring opportunities that may lead to new smells that will go unnoticed. This paper addresses the side effects of software refactoring and proposes sound solutions for handling them. Unlike current practices in software maintenance, we recommend three different approaches to handle the refactoring side effects. In the first approach, called the baseline, we opt to ignore the smells, caused by refactoring, while executing the identified refactoring decisions. In the second one, refactoring decisions are continually updated to fix all smells caused by side effects. In the last approach, only a subset of these smells is appended to the original smell sequence during the execution of the refactoring decisions. Thanks to the proposed approaches, optimal refactoring decisions are identified using a multi‐objective (MO) optimization algorithm commonly known as the MO covariance matrix adaptation evolution strategy (MO‐CMA‐ES). Experiment results corroborate our assumptions and show the superiority of the second approach over the other ones.
Natural Products & Bioactivity Inspired Synthetic Pursuits Interfacing with Carbohydrates: Ongoing Journey with C‐Glycosides
Authors: Singh Aidhen Indrapal , Thoti Naveenkumar
Published: October 2021

Natural products, remains the most important source for the discovery of new drugs for the treatment of human diseases. This has inspired the synthetic community to design and develop mimics of natural products either to answer important questions in biology or to explore their therapeutic potentials. Glycosides present themselves abundantly in nature, right from the cell surface receptors to natural products of any origin. The O‐Glycosides are hydrolytically less stable compared to C‐glycosides and this feature has presented a great opportunity for drug discovery. The discovery of Dapagliflozin, an SGLT inhibitor and C‐glucoside, for the treatment of diabetes is one such example. Aryl acyl‐anion chemistry has been explored for the synthesis of 2‐deoxy‐C‐aryl furanoside/pyranoside/septanosides. Besides success, the studies have provided valuable insight into the natural propensities of the architectural framework for the cascade to furan derivatives. The aryl acyl‐anion chemistry has also enabled the synthesis of biologically active diaryl heptanoids. Inspired from sucesss of Dapagliflozin, new analogues have been synthesized with pyridine and isocoumarin heterocycle as the proximal ring. C‐glucosides of isoliquiritigenin have been synthesized for the first time and evaluated as an efficient aldose reductase inhibitor. The synthesis and evaluation of acyl‐C‐β‐D‐glucosides and benzyl‐C‐β‐D‐glucoside as glucose‐uptake promoters has revealed promise in small molecules. The concept of building blocks has been used to obtain natural oxylipins, D‐xylo and L‐xylo‐configured alkane tetrols and novel lipophilic ketones with erythro/threo configured trihydroxy polar head‐group as possible anti‐mycobacterial agents.
Cyclisations and Strategies for Stereoselective Synthesis of Piperidine Iminosugars
Authors: Dhara Debashis , Dhara Ashis , Bennett Jack , Murphy Paul V.
Published: October 2021

This personal account focuses on synthesis of polyhydroxylated piperidines, a subset of compounds within the iminosugar family. Cyclisations to form the piperidine ring include reductive amination, substitution via amines, iminium ions and cyclic nitrones, transamidification (N‐acyl transfer), addition to alkenes, ring contraction and expansion, photoinduced electron transfer, multicomponent Ugi reaction and ring closing metathesis. Enantiomerically pure piperidines are obtained from chiral pool precursors (e. g. sugars, amino acids, Garner's aldehyde) or asymmetric reactions (e. g. epoxidation, dihydroxylation, aminohydroxylation, aldol, biotransformation). Our laboratory have contributed cascades based on reductive amination from glycosyl azide precursors as well as Huisgen azide‐alkene cycloaddition. The latter's combination with allylic azide rearrangement has given substituted piperidines, including those with quaternary centres adjacent to nitrogen.
How smooth is quantum complexity?
Authors: Bulchandani Vir B. , Sondhi S. L.
Published: October 2021

Abstract

The “quantum complexity” of a unitary operator measures the difficulty of its construction from a set of elementary quantum gates. While the notion of quantum complexity was first introduced as a quantum generalization of the classical computational complexity, it has since been argued to hold a fundamental significance in its own right, as a physical quantity analogous to the thermodynamic entropy. In this paper, we present a unified perspective on various notions of quantum complexity, viewed as functions on the space of unitary operators. One striking feature of these functions is that they can exhibit non-smooth and even fractal behaviour. We use ideas from Diophantine approximation theory and sub-Riemannian geometry to rigorously quantify this lack of smoothness. Implications for the physical meaning of quantum complexity are discussed.
Target space entanglement in Matrix Models
Authors: Hampapura Harsha R. , Harper Jonathan , Lawrence Albion
Published: October 2021

Abstract

We study target space entanglement in gauged multi-matrix models as models of entanglement between groups of D-branes separated by a planar entangling surface, paying close attention to the implementation of gauge invariance. We open with a review of target space entanglement between identical particles, which shares some important features (specifically a gauged permutation symmetry) with our main problem. For our matrix models, we implement a gauge fixing well-adapted to the entangling surface. In this gauge, we map the matrix model problem to that of entanglement of a U(1) gauge theory on a complete or all-to-all lattice. Matrix elements corresponding to open strings stretching across the entangling surface in the target space lead to interesting contributions to the entanglement entropy.
Production of heavy charged particles in proton-proton ultraperipheral collisions at the Large Hadron Collider: survival factor
Authors: Godunov S. I. , Novikov V. A. , Rozanov A. N. , Vysotsky M. I. , Zhemchugov E. V.
Published: October 2021

Abstract

Ultraperipheral collisions of high energy protons are a source of approximately real photons colliding with each other. Photon fusion can result in production of yet unknown charged particles in very clean events. The cleanliness of such an event is due to the requirement that the protons survive during the collision. Finite sizes of the protons reduce the probability of such outcome compared to point-like particles. We calculate the survival factors and cross sections for the production of heavy charged particles at the Large Hadron Collider.
Eigenstate Thermalization Hypothesis for Wigner Matrices
Authors: Cipolloni Giorgio , Erdős László , Schröder Dominik
Published: October 2021

We prove that any deterministic matrix is approximately the identity in the eigenbasis of a large random Wigner matrix with very high probability and with an optimal error inversely proportional to the square root of the dimension. Our theorem thus rigorously verifies the Eigenstate Thermalisation Hypothesis by Deutsch (Phys Rev A 43:2046–2049, 1991) for the simplest chaotic quantum system, the Wigner ensemble. In mathematical terms, we prove the strong form of Quantum Unique Ergodicity (QUE) with an optimal convergence rate for all eigenvectors simultaneously, generalizing previous probabilistic QUE results in Bourgade and Yau (Commun Math Phys 350:231–278, 2017) and Bourgade et al. (Commun Pure Appl Math 73:1526–1596, 2020).
A new approach to correct the overestimated persistence in tree-ring width based precipitation reconstructions
Authors: Yuan Naiming , Xiong Feilin , Xoplaki Elena , He Wenping , Luterbacher Jürg
Published: October 2021

Tree-ring width is one of the most widely used proxy in paleoclimatological studies. Due to various environmental and biological processes, however, the associated reconstructions often suffer from overestimated low-frequency variability. In this study, a new correction approach is proposed using fractional integral techniques that corrects for the overestimated long-term persistence in tree-ring width based hydroclimatic reconstructions. Assuming the high frequency interannual climate variability is well recorded by tree rings, the new approach is able to (i) extract the associated short-term forcing signals of various climate conditions from the reconstructions, and (ii) simulate the long-term impacts of these short-term forcings by setting a proper fractional integral order in the fractional integral statistical model (FISM). In this way, the overestimated long-term persistence, as well as the associated low-frequency variability in tree-ring width based reconstructions can be corrected. We apply this approach to a recently published dataset of precipitation field reconstructions over China covering the past half millennium and removed the redundant, non-precipitation related long-term persistence. Compared to the original reconstruction with multi-century long-term dry conditions in western China, the corrected reconstruction considerably shortened the wet/dry periods to decadal scales. In view of the widespread non-climatic/mixed-climatic signals in tree-ring widths, this new approach may serve as a useful post-processing method to reconsider previous reconstructions. It may even be combined with the current detrending approaches by upgrading the pre-whitening methods.
Are there differences between officers and ratings on merchant vessels concerning effort–reward imbalance: a cross-sectional maritime field study
Authors: Oldenburg Marcus , Jensen Hans-Joachim
Published: October 2021

Purpose

Today, measures to economise in the operation of ships can cause either an effort–reward imbalance or health impairments. The goal of this study was to assess the risk of effort–reward imbalance including overcommitment among officers and ratings on merchant vessels during their assignments and to evaluate lifestyle factors of seafarers as well as the health-promoting conditions on board.

Methods

A study sample of 308 male seafarers was examined during a total of 20 sea voyages on German container ships (participation rate 91.9%).

Results

Only 11 seafarers were identified as having an increased health risk of an effort–reward imbalance (ER ratio > 1). Officers tended to have a higher risk of an elevated ratio than ratings (4.4% vs. 3.1%) and also showed a significantly higher risk of an ER ratio above the median (58.8% vs. 41.8%; p = 0.022). Compared to land-based populations, the average overcommitment score of seafarers was high (17.9)—particularly among officers (20.3 vs. 16.5; p = 0.031). This corresponded to an elevated risk of overcommitment among officers compared to ratings (OR 2.14; 95% CI 1.78–2.37). This elevated risk remained significant after adjustment for age (OR 2.11; 95% CI 1.76–2.35) and job-related stressors.

Conclusion

Although an elevated risk of effort–reward imbalance was only observed in few seafarers, this study revealed a high prevalence of overcommitment particularly among officers. In the course of time, overcommitment can lead to mental exhaustion. Therefore, shipboard health-promoting conditions need to be optimised.
Manual delineation approaches for direct imaging of the subcortex
Authors: Alkemade Anneke , Mulder Martijn J. , Trutti Anne C. , Forstmann Birte U.
Published: October 2021

The growing interest in the human subcortex is accompanied by an increasing number of parcellation procedures to identify deep brain structures in magnetic resonance imaging (MRI) contrasts. Manual procedures continue to form the gold standard for parcellating brain structures and is used for the validation of automated approaches. Performing manual parcellations is a tedious process which requires a systematic and reproducible approach. For this purpose, we created a series of protocols for the anatomical delineation of 21 individual subcortical structures. The intelligibility of the protocols was assessed by calculating Dice similarity coefficients for ten healthy volunteers. In addition, dilated Dice coefficients showed that manual parcellations created using these protocols can provide high-quality training data for automated algorithms. Here, we share the protocols, together with three example MRI datasets and the created manual delineations. The protocols can be applied to create high-quality training data for automated parcellation procedures, as well as for further validation of existing procedures and are shared without restrictions with the research community.
Root form and canal anatomy of maxillary first premolars: a cone-beam computed tomography study
Authors: Olczak Katarzyna , Pawlicka Halina , Szymański Witold
Published: October 2021

The aim of this study was to evaluate the root and canal morphology of permanent maxillary first premolars in a Polish population using cone-beam computed tomography scanning (CBCT) and to compare the classifications by Vertucci and Ahmed et al. Images of 350 maxillary first premolars were analyzed. Scans were obtained from 226 patients: 131 women and 95 men. The root canal configurations were classified according to Vertucci and a new system by Ahmed et al. In addition, the number of roots and the level where roots bifurcated were identified. The results were submitted to statistical analysis. Most maxillary first premolars had two roots (69.1%). Most bifurcations were located in the coronal part of the root (44.2%) and the least in the apical part (15.3%). Bifurcation in the coronal part of the root was observed more often in the teeth of men than women. In turn, bifurcation in the central or apical part was significantly more common in women than in men. The most common canal configuration of the maxillary first premolars was type IV (78.2%) according to Vertucci and 2FPB1P1 (65.4%) according to the new classification. Among the remaining cases, almost all types of canals described by Vertucci, and many combinations of codes given in the new classification were demonstrated. The maxillary first premolars displayed a wide range of root and canal anatomical variations. The new system for classifying canal morphology based on Ahmed et al. is more accurate than the Vertucci classification.
Post mortem brain temperature and its influence on quantitative MRI of the brain
Authors: Berger Celine , Bauer Melanie , Wittig Holger , Scheurer Eva , Lenz Claudia
Published: October 2021

Objective

MRI temperature sensitivity presents a major issue in in situ post mortem MRI (PMMRI), as the tissue temperatures differ from living persons due to passive cooling of the deceased. This study aims at computing brain temperature effects on the MRI parameters to correct for temperature in PMMRI, laying the foundation for future projects on post mortem validation of in vivo MRI techniques.

Materials and methods

Brain MRI parameters were assessed in vivo and in situ post mortem using a 3 T MRI scanner. Post mortem brain temperature was measured in situ transethmoidally. The temperature effect was computed by fitting a linear model to the MRI parameters and the corresponding brain temperature.

Results

Linear positive temperature correlations were observed for T1, T2* and mean diffusivity in all tissue types. A significant negative correlation was observed for T2 in white matter. Fractional anisotropy revealed significant correlations in all gray matter regions except for the thalamus.

Discussion

The linear models will allow to correct for temperature in post mortem MRI. Comparing in vivo to post mortem conditions, the mean diffusivity, in contrast to T1 and T2, revealed additional effects besides temperature, such as cessation of perfusion and active diffusion.
Now, I think doctors can be heroes … Medical student’s attitudes towards the COVID-19 pandemic’s impact on key aspects of medical education and how the image of the medical profession has changed due to the COVID-19 pandemic
Authors: Steiner-Hofbauer Verena , Grundnig Julia S. , Drexler Viktoria , Holzinger Anita
Published: October 2021

Background

The COVID-19 (coronavirus disease 2019) pandemic hit the world in early 2020 and influenced medical education worldwide. Distance learning, risk of infection and patient care, telehealth literacy, medical ethics and research in medical education are key factors of medical education challenged by the pandemic. Additionally, the following question arises: “What do medical students think about their future profession in the face of this crisis?”

Methods

A cross-sectional survey was conducted among all undergraduate medical students of the Medical University of Vienna. 872 students answered the self-developed questionnaire. Qualitative and quantitative data analyses were conducted.

Results

The data show that the COVID-19 pandemic has raised awareness for the key aspects. In all areas of interest, students’ feeling of petaredness is limited. Limitations in practical training and distance learning as well as social isolation concern a majority of students. Neutral, positive, and negative themes emerged in qualitative data analysis. Only 8% of the students of the first 3 years of study versus 13.4% of the students in higher years commented negatively. 18.7% of male vs. only 12.5% of all female students’ comments were positive. A large proportion of positive comments were dedicated to the relevance and deeper meaning of the medical profession. Infection risk and the demanding nature of the medical profession were predominant in negative comments.

Conclusion

The COVID-19 crisis has turned the spotlight on several aspects of medical education in need of reform. In addition, the occupational image of the medical profession seems to shift under the weight of this pandemic.
The role of changing pH on olfactory success of predator–prey interactions in green shore crabs, Carcinus maenas
Authors: Richardson Bryce , Martin Holly , Bartels-Hardege Helga , Fletcher Nichola , Hardege Jörg Detlef
Published: October 2021

Arguably climate change is one of the biggest challenges faced by many organisms. One of the more significant of these is the decreasing pH level of the ocean, a consequence of the increasing amount of atmospheric CO2 being absorbed. With the current open ocean pH level of 8.15 projected to fall to just over 7.6 in 2100, the impacts could be devastating for marine species reliant upon olfaction to survive. Here, we show that Carcinus maenas (shore crab) can detect and respond to the presence of odour cues from predatory species with no significant change between both current and projected pH conditions. In contrast, C. maenas ability to detect and respond to prey cues is altered in the projected climate change conditions, with a delayed response being observed at pH 7.6. A difference can be seen between males and females, with males detecting prey cues faster than females in reduced pH, suggesting the potential for males to be better acclimated to future climate change conditions. The change in ocean chemistry is postulated to have a fundamental impact on chemical communication systems in aquatic species. Here, we show such negative impacts of altered pH on feeding responses in Carcinus maenas, a typically robust keystone intertidal species and confirm that not all behaviours are affected equally with potentially significant implications for such functional traits and species interactions.
The H3K27 demethylase controls the lateral line embryogenesis of zebrafish
Authors: Tang Dongmei , Lu Yitong , Zuo Na , Yan Renchun , Wu Cheng , Wu Lijuan , Liu Shaofeng , He Yingzi
Published: October 2021

Background

Kdm6b, a specific histone 3 lysine 27 (H3K27) demethylase, has been reported to be implicated in a variety of developmental processes including cell differentiation and cell fate determination and multiple organogenesis. Here, we regulated the transcript level of kdm6bb to study the potential role in controlling the hearing organ development of zebrafish.

Methods

A morpholino antisense oligonucleotide (MO) strategy was used to induce Kdm6b deficiency; immunohistochemical staining and in situ hybridization analysis were conducted to figure out the morphologic alterations and embryonic mechanisms.

Results

Kdm6bb is expressed in the primordium and neuromasts at the early stage of zebrafish embryogenesis, suggesting a potential function of Kdm6b in the development of mechanosensory organs. Knockdown of kdm6bb severely influences the cell migration and proliferation in posterior lateral line primordium, abates the number of neuromasts along the trunk, and mRNA-mediated rescue test can partially renew the neuromasts. Loss of kdm6bb might be related to aberrant expressions of chemokine genes encompassing cxcl12a and cxcr4b/cxcr7b in the migrating primordium. Moreover, inhibition of kdm6bb reduces the expression of genes in Fgf signaling pathway, while it increases the axin2 and lef1 expression level of Wnt/β-catenin signaling during the migrating stage.

Conclusions

Collectively, our results revealed that Kdm6b plays an essential role in guiding the migration of primordium and in regulating the deposition of zebrafish neuromasts by mediating the gene expression of chemokines and Wnt and Fgf signaling pathway. Since histone methylation and demethylation are reversible, targeting Kdm6b may present as a novel therapeutic regimen for hearing disorders.
Combined Lorentz Symmetry: Lessons from Superfluid $$^3$$He
Authors: Volovik G. E.
Published: October 2021

We consider the possibility of the scenario in which the P, T and Lorentz symmetry of the relativistic quantum vacuum are all the combined symmetries. These symmetries emerge as a result of the symmetry breaking of the more fundamental P, T and Lorentz symmetries of the original vacuum, which is invariant under separate groups of the coordinate transformations and spin rotations. The condensed matter vacua (ground states) suggest two possible scenarios of the origin of the combined Lorentz symmetry, and both are realized in the superfluid phases of liquid $$^3$$

3

He: the $$^3$$

3

He-A scenario and the $$^3$$

3

He-B scenario. In these scenarios, the gravitational tetrads are considered as the order parameter of the symmetry breaking in the quantum vacuum. The $$^3$$

3

He-B scenarios applied to the Minkowski vacuum lead to the continuous degeneracy of the Minkowski vacuum with respect to the O(3, 1) spin rotations. The symmetry breaking leads to the corresponding topological objects, which appear due to the nontrivial topology of the manifold of the degenerate Minkowski vacua, such as torsion strings. The fourfold degeneracy of the Minkowski vacuum with respect to discrete P and T symmetries suggests that the Weyl fermions are described by four different tetrad fields: the tetrad for the left-handed fermions, the tetrad for the right-handed fermions, and the tetrads for their antiparticles. This may lead to the gravity with several metric fields, so that the parity violation may lead to the breaking of equivalence principle. Finally, we considered the application of the gravitational tetrads for the solution of the cosmological constant problem.