bluuebunny/crossref_metadata_2025 huggingface dataset:
Global survey of star clusters in the Milky Way
Authors: Just A. , Piskunov A. E. , Klos J. H. , Kovaleva D. A. , Polyachenko E. V.
Published: February 2023

Aims. We built Galactic open star cluster mass functions (CMFs) for different age sub-samples and spatial locations in the wider solar neighbourhood. Here, we present a simple cluster formation and evolution model to reproduce the main features of the CMFs.

Methods. We used an unbiased working sample of 2227 clusters of the Milky Way Star Cluster (MWSC) catalogue, which occupy the heliocentric cylinders with magnitude-dependent completeness radii of 1–5 kpc. The MWSC survey provides an extended set of open star cluster parameters, including tidal radii, distances, and ages. From an analytic three-component Galaxy model, we derived tidal masses of clusters with a typical accuracy of about 70%. Our simple model includes a two-section cluster initial mass function, constant cluster formation rate, supervirial phase after a sudden expulsion of the remaining gas, and cluster mass loss due to stellar evolution and the clusters’ gradual destruction in the Galactic tidal field. The dynamical evolution model is based on previous N-body simulations.

Results. The obtained tidal masses have been added to the MWSC catalogue. A general CMF (GCMF), built for all cluster ages around the Sun, has a bell-like shape and extends over four decades in mass. The high-mass slope found for tidal mass log mt/M⊙ ≥ 2.3 is equal to 1.14 ± 0.07. The CMFs for different age groups show the same high-mass slopes, while the low-mass slope is nearly flat for the youngest sub-sample (clusters younger than 20 Myr) and about −0.7 for the others. The inner and outer sub-samples covering Galactocentric radii R = 4.2–8.1 kpc and 8.9–13.5 kpc, respectively, are consistent with the GCMF, once the exponential decline of the Galactic disc density is taken into account. The model suggests star formation with low efficiency of 15–20%, where only 10% of stars remain bound in a cluster after gas expulsion and subsequent violent relaxation. The cluster formation rate required to reproduce the observed distributions in age and mass is about 0.4 M⊙ pc−2 Gyr−1.

Conclusions. The obtained high-mass slope of the GCMF for the wide neighbourhood of the Sun is similar to slopes determined earlier in nearby galaxies for more luminous clusters with log m/M⊙ > 3.8. The MWSC catalogue supports models with a low star-formation efficiency, where 90% of stars are lost quickly after gas expulsion. The obtained cluster formation rate corresponds to open clusters’ contribution to the stellar content of the thin disc at the level of 30%.
Neutrino search fromγ-ray bursts during the prompt and X-ray afterglow phases using 10 years of IceCube public data
Authors: Lucarelli Francesco , Oganesyan Gor , Montaruli Teresa , Branchesi Marica , Mei Alessio , Ronchini Samuele , Brighenti Francesco , Banerjee Biswajit , Voutsinas Georgios Gerasimos
Published: February 2023

Neutrino emission fromγ-ray bursts (GRBs) has been sought for a long time, and stringent limits on the most accredited GRB emission models have been obtained from IceCube. Multiwavelength GRB observations of the last decades have improved our knowledge of the GRB emission parameters, such as the Lorentz factor and the luminosity, which can vary from one GRB to another by several orders of magnitude. Empirical correlations among such parameters have been identified during the prompt phase, with direct implications on GRB models. In this work, we use the PSLab open-access code, developed for IceCube data analyses, to search for individual neutrino emission from the prompt and afterglow phases of selected GRBs, and for stacking emission from the ensemble of such GRBs. For the afterglow phase, we focus on GRBs with X-ray flares and plateaus in particular. While past stacking searches assumed the same GRB fluence at Earth, we present a stacking scheme based on physically motivated GRB weights. Moreover, we conceive a new methodology for the prompt phase that uses the empirical correlations to infer the GRB luminosity and Lorentz factor, when redshift measurements are not available. We do not observe any significant neutrino excess. Hence, we set constraints on the GRB neutrino fluxes and on relevant GRB parameters, including the magnetic field in the jet. Notably, the baryon loading is found to be less than ten for typical GRB jets.
Helios 2 observations of solar wind turbulence decay in the inner heliosphere
Authors: Sorriso-Valvo L. , Marino R. , Foldes R. , Lévêque E. , D’Amicis R. , Bruno R. , Telloni D. , Yordanova E.
Published: February 2023

Aims. A linear scaling of the mixed third-order moment of the magnetohydrodynamic (MHD) fluctuations is used to estimate the energy transfer rate of the turbulent cascade in the expanding solar wind.

Methods. In 1976, the Helios 2 spacecraft measured three samples of fast solar wind originating from the same coronal hole, at different distances from the Sun. Along with the adjacent slow solar wind streams, these intervals represent a unique database for studying the radial evolution of turbulence in samples of undisturbed solar wind. A set of direct numerical simulations of the MHD equations performed with the Lattice-Boltzmann code FLAME was also used for interpretation.

Results. We show that the turbulence energy transfer rate decays approximately as a power law of the distance and that both the amplitude and decay law correspond to the observed radial temperature profile in the fast wind case. Results from MHD numerical simulations of decaying MHD turbulence show a similar trend for the total dissipation, suggesting an interpretation of the observed dynamics in terms of decaying turbulence and that multi-spacecraft studies of the solar wind radial evolution may help clarify the nature of the evolution of the turbulent fluctuations in the ecliptic solar wind.
The NuSTAR view of the changing-look AGN ESO 323-G77
Authors: Serafinelli Roberto , Braito Valentina , Reeves James N. , Severgnini Paola , De Rosa Alessandra , Della Ceca Roberto , Jane Turner Tracey
Published: February 2023

The presence of an obscuring torus at parsec-scale distances from the central black hole is the main ingredient for the Unified Model of active galactic nuclei (AGN), as obscured sources are thought to be seen through this structure. However, the Unified Model fails to describe a class of sources that undergo dramatic spectral changes, transitioning from obscured to unobscured and vice versa through time. The variability in these sources, which are known as changing-look AGN (CLAGN), is thought to be produced by a clumpy medium at much smaller distances than the conventional obscuring torus. ESO 323-G77 is a CLAGN that was observed in various states through the years with Chandra, Suzaku, Swift-XRT, and XMM-Newton, from unobscured (NH < 3 × 1022 cm−2) to Compton-thin (NH ∼ 1 − 6 × 1023 cm−2) and even Compton-thick (NH > 1 × 1024 cm−2), on timescales as short as one month. We present an analysis of the first NuSTAR monitoring of ESO 323-G77, consisting of five observations taken at different timescales (1, 2, 4, and 8 weeks from the first one) in 2016–2017, in which the AGN was caught in a persistent Compton-thin obscured state (NH ∼ 2 − 4 × 1023 cm−2). We find that a Compton-thick reflector is present (NH, refl = 5 × 1024 cm−2), most likely associated with the presence of the putative torus. Two ionized absorbers are unequivocally present, located within maximum radii of rmax, 1 = 1.5 pc and rmax, 2 = 0.01 pc. In one of the observations, the inner ionized absorber is blueshifted, indicating the presence of a possible faster (vout = 0.2c) ionized absorber, marginally detected at 3σ. Finally, we are able to constrain the coronal temperature and the optical depth of ESO 323-G77, obtaining kTe = 38 keV or kTe = 36 keV, and τ = 1.4 or τ = 2.8, depending on the coronal geometry assumed.
Jets in FR0 radio galaxies
Authors: Giovannini G. , Baldi R. D. , Capetti A. , Giroletti M. , Lico R.
Published: February 2023

Context.The local radio-loud AGN population is dominated by compact sources named FR0s. These sources show features, for example the host type, the mass of the supermassive black hole (SMBH), and the multi-band nuclear characteristics, that are similar to those of FRI radio galaxies. However, in the radio band, while FR0 and FRI share the same nuclear properties, the kiloparsec-scale diffuse component dominant in FRI is missing in FR0s. Previous very-long-baseline interferometry (VLBI) observations of a small sample of FR0s show a complex structure, mostly symmetric (two-sided jets) with respect to the central core.

Aims.With this project we would like to study the parsec-scale structure in FR0s in comparison with that of FRI sources. Jets in FRI are relativistic on the parsec scale and decrease their velocity becoming subrelativistic on the kiloparsec scale. We would like to test whether this result also applies to the jets in FR0s or, alternatively, whether they are subrelativistic on the parsec scale. This might be the reason why they are unable to grow, because of instabilities, related to a low jet bulk velocity.

Methods.To this end we observed 18 FR0 galaxies with the VLBA at 1.5 and 5 GHz and/or with the EVN at 1.7 GHz and produced detailed images at milliarcsec resolution of their nuclear emission to study the jet and core structure.

Results.All sources have been detected but one. Four sources are unresolved, even in these high-resolution images; jets have been detected in all other sources. We derived the distribution of the jet-to-counter-jet ratio of FR0s and found that it is significantly different from that of FRIs, suggesting different jet bulk speed velocities.

Conclusions.Combining the present data with published data of FR0 with VLBI observations, we derive that the radio structure of FR0 galaxies shows strong evidence that parsec-scale jets in FR0 sources are mildly relativistic with a bulk velocity on the order of 0.5c or less. A jet structure with a thin inner relativistic spine surrounded by a low-velocity sheath could be in agreement with the SMBH and jet launch region properties.
Search engine marketing for different competition modes – Interfirm and intrafirm
Authors: Zhang Xueli , Yang Defeng , Li Can
Published: February 2023

Brands seeking for prominent positions in online consumer search may invest in two types of search engine marketing: paid search marketing (PSM) and search engine optimization (SEO). This paper investigates how firms should allocate marketing resources between PSM and SEO under different competition modes (interfirm and intrafirm competition). We develop an analytical model where within an interfirm competition, two brands compete for every step, while for the intrafirm competition, multi-brand firm coordinates the search engine marketing decisions for its brands, but delegates the price decisions to the brand managers. We find that the resource allocation decision may depend on the firm’s brand strength in organic search. Our analysis shows an increasing curve relation between resources allocated to PSM and the brand strength for interfirm competition and inverted-U shape for intrafirm competition. More specifically, as the brand strength goes up, for the interfirm competition, the resources allocated to PSM increase till 100%, while it should increase only when brand strength is sufficiently low, but decrease when brand strength is high for the intrafirm competition. This nontrivial result underscores the challenge facing a multi-brand firm in balancing between maximizing the search prominence for the category and minimizing the internal competition.
Preparation, Characterization and Evaluation of a Novel Drug Carrier
for the Controlled Release of Curcumin
Authors: Kasim Faseela , Nair Archana Somasekharan , Lalitha Balachandran Aswathy , Sooraj Moorikoval Parambil , Nair Anoop Somasekharan
Published: February 2023

The upsurge of cancer demands intense, rapid and effective intervention from the
scientific society. Even though nanoparticles helped achieving this, maintaining
its size without using toxic capping agents is challenging. Phytochemicals
having reducing properties is a proper substitute and the efficiency of such
nanoparticles could be further improved by grafting with suitable monomers. It
could be further protected from rapid biodegradation by coating with suitable
materials. This approach was utilized wherein, the green synthesized silver
nanoparticles (AgNps) were initially functionalized with –COOH to couple
with –NH2 groups of ethylene diamine. It was then coated with
polyethylene glycol (PEG) and hydrogen bonded with curcumin. The formed amide
bonds could effectively uptake drug molecules and sensed environmental pH.
Swelling studies and release profiles confirmed selective drug release. All
these results along with those obtained from MTT assay, suggested the potential
applicability of the prepared material in pH sensitive drug delivery of
curcumin.
The Effect on the Birth Process of Endogenous Oxytocin Release Via
Coitus at Home in Pregnant Women in the Latent Phase
Authors: Kurt Begum , Demirel Gulbahtiyar , Caglayan Ilkin Seda , Doganer Adem
Published: February 2023

Objectives This study was conducted to determine the effect of endogenous
oxytocin release via coitus at home on the delivery process in pregnant women
who were not hospitalized in the latent phase.

Background For healthy pregnant women who can deliver spontaneously, it is
recommended to be admitted to the delivery room during the active phase of
labor. When the pregnant woman is admitted to the delivery room in the latent
phase before the active stage, pregnant women spend more time in the delivery
room, which makes medical intervention inevitable.

Methods 112 pregnant women for whom hospitalization in the latent phase
was recommended were included in the randomized controlled study. They were
divided into two groups in which sexual activity in the latent phase was
recommended (n=56) and the control group (n=56).

Results In our study, the duration of the 1st stage of labor was found to
be significantly shorter in the group in which sexual activity in the latent
phase was recommended, compared to the control group (p=0.001). Again,
the need for amniotomy, labor induction with oxytocin, analgesics and episiotomy
decreased.

Conclusion Sexual activity can be considered as a natural way to speed up
labor, reduce medical interventions, and prevent postterm pregnancy.
Electrosynthesis of Flavanones via oxa-Michael Addition Using Sacrificial Electrodes
Authors: Martins Guilherme M. , Mendes Samuel R. , Santos William A. B. , de Castro Pedro P. , Xavier Fernando R. , Braga Antonio L.
Published: February 2023

An electrochemical synthesis of flavanones via oxa-Michael addition using silver electrode as a sacrifice is reported. This electrosynthetic system showed good yields, broad substrate scope, and good functional group tolerance. Additionally, the method proved to be applicable on a gram-scale. Several studies were carried out to elucidate the reaction mechanism, such as control reactions, cyclic voltammetry, and theoretical studies, allowing the proposal of a plausible pathway for this transformation.
An Alternative Application of Natural Language Processing to Express a Characteristic Feature of Diseases in Japanese Medical Records
Authors: Yamanouchi Yoshinori , Nakamura Taishi , Ikeda Tokunori , Usuku Koichiro
Published: February 2023

Background Owing to the linguistic situation, Japanese natural language processing (NLP) requires morphological analyses for word segmentation using dictionary techniques.

Objective We aimed to clarify whether it can be substituted with an open-end discovery-based NLP (OD-NLP), which does not use any dictionary techniques.

Methods Clinical texts at the first medical visit were collected for comparison of OD-NLP with word dictionary-based-NLP (WD-NLP). Topics were generated in each document using a topic model, which later corresponded to the respective diseases determined in International Statistical Classification of Diseases and Related Health Problems 10 revision. The prediction accuracy and expressivity of each disease were examined in equivalent number of entities/words after filtration with either term frequency and inverse document frequency (TF-IDF) or dominance value (DMV).

Results In documents from 10,520 observed patients, 169,913 entities and 44,758 words were segmented using OD-NLP and WD-NLP, simultaneously. Without filtering, accuracy and recall levels were low, and there was no difference in the harmonic mean of the F-measure between NLPs. However, physicians reported OD-NLP contained more meaningful words than WD-NLP. When datasets were created in an equivalent number of entities/words with TF-IDF, F-measure in OD-NLP was higher than WD-NLP at lower thresholds. When the threshold increased, the number of datasets created decreased, resulting in increased values of F-measure, although the differences disappeared. Two datasets near the maximum threshold showing differences in F-measure were examined whether their topics were associated with diseases. The results showed that more diseases were found in OD-NLP at lower thresholds, indicating that the topics described characteristics of diseases. The superiority remained as much as that of TF-IDF when filtration was changed to DMV.

Conclusion The current findings prefer the use of OD-NLP to express characteristics of diseases from Japanese clinical texts and may help in the construction of document summaries and retrieval in clinical settings.
Radical Cation [2+2] Cycloadditions Enabled by Surface-Assisted Pseudo-Intramolecular Electron Transfers
Authors: Okada Yohei , Adachi Sota , Maeta Naoya , Nakayama Kaii , Wang Zimo , Hashimoto Yasuhiro
Published: February 2023

Both intermolecular and intramolecular electron transfers can be the key in the determination of synthetic outcomes of photochemical and electrochemical reactions. Herein, we report dispersed TiO2 nanoparticles in combination with methoxybenzene to be a unique heterogeneous photocatalyst for facilitating the formation of novel cyclobutanes. Although the mechanistic details are as yet unclear, the results described herein imply that methoxybenzene is adsorbed onto the TiO2 surface, coming in close proximity to the forming cyclobutane radical cation, to realize a pseudo-intramolecular electron transfer between the species.
Synthetic Strategies to Control C–N Atropisomerism in Acyclic Amines and Amides
Authors: Armstrong Roly J. , Campbell Aaron D. G.
Published: February 2023

Atropisomeric molecules are a privileged class of stereogenic material that have important applications in catalysis, materials science and medicines. To date, the majority of work has been focused upon biaryl and heterobiaryl scaffolds involving restricted rotation between a pair of cyclic fragments, but C–N atropisomeric molecules based upon amines and amides, where the nitrogen atom is not part of a ring system, are rapidly emerging as an important class of stereogenic molecules. This is the focus of this Short Review, which begins by discussing the factors which influence the configurational stability of such molecules and provides a historical background to their synthesis. This is followed by a detailed discussion of state-of-the-art catalytic asymmetric strategies that are now available to access C–Nacyclic atropisomers including carboxamides, sulfonamides, sulfinamides, phosphamides and diarylamines. A variety of different synthetic approaches are discussed, including kinetic resolution/desymmetrization, amination, C–H functionalization, N-functionalization, and annulation.

1 Introduction

2 Atropisomerism in Acyclic Amines and Amides

3 Synthesis Directed by a Chiral Auxiliary

4 Atropselective Synthesis

4.1 Kinetic Resolution and Desymmetrization

4.2 Electrophilic Amination

4.3 C–H Functionalization

4.4 N-Functionalization

4.5 Annulation

5 Conclusions and Outlook
Human-Centered Design of a Clinical Decision Support for Anemia Screening in Children with Inflammatory Bowel Disease
Authors: Miller Steven D. , Murphy Zachary , Gray Joshua H. , Marsteller Jill , Oliva-Hemker Maria , Maslen Andrew , Lehmann Harold P. , Nagy Paul , Hutfless Susan , Gurses Ayse P.
Published: February 2023

Background Inflammatory bowel disease (IBD) commonly leads to iron deficiency anemia (IDA). Rates of screening and treatment of IDA are often low. A clinical decision support system (CDSS) embedded in an electronic health record could improve adherence to evidence-based care. Rates of CDSS adoption are often low due to poor usability and fit with work processes. One solution is to use human-centered design (HCD), which designs CDSS based on identified user needs and context of use and evaluates prototypes for usefulness and usability.

Objectives this study aimed to use HCD to design a CDSS tool called the IBD Anemia Diagnosis Tool, IADx.

Methods Interviews with IBD practitioners informed creation of a process map of anemia care that was used by an interdisciplinary team that used HCD principles to create a prototype CDSS. The prototype was iteratively tested with “Think Aloud” usability evaluation with clinicians as well as semi-structured interviews, a survey, and observations. Feedback was coded and informed redesign.

Results Process mapping showed that IADx should function at in-person encounters and asynchronous laboratory review. Clinicians desired full automation of clinical information acquisition such as laboratory trends and analysis such as calculation of iron deficit, less automation of clinical decision selection such as laboratory ordering, and no automation of action implementation such as signing medication orders. Providers preferred an interruptive alert over a noninterruptive reminder.

Conclusion Providers preferred an interruptive alert, perhaps due to the low likelihood of noticing a noninterruptive advisory. High levels of desire for automation of information acquisition and analysis with less automation of decision selection and action may be generalizable to other CDSSs designed for chronic disease management. This underlines the ways in which CDSSs have the potential to augment rather than replace provider cognitive work.
Incidence of Venous Thromboembolism Based on Caprini Score in Deep Inferior Epigastric Perforator Flap Breast Reconstruction
Authors: Wu Shannon S. , Raymer Charles , Schafer Rachel , Culbert August , Bernard Steven , Djohan Risal , Schwarz Graham , Bishop Sarah N. , Gurunian Raffi
Published: February 2023

Background Deep inferior epigastric perforator (DIEP) flaps are commonly used for autologous breast reconstruction, but reported rates of venous thromboembolism (VTE) are up to 6.8%. This study aimed to determine the incidence of VTE based on preoperative Caprini score following DIEP breast reconstruction.

Methods This retrospective study included patients who underwent DIEP flaps for breast reconstruction between January 1, 2016 and December 31, 2020 at a tertiary-level, academic institution. Demographics, operative characteristics, and VTE events were recorded. Receiver operating characteristic analysis was performed to determine the area under the curve (AUC) of the Caprini score for VTE. Univariate and multivariate analyses assessed risk factors associated with VTE.

Results This study included 524 patients (mean age 51.2 ± 9.6 years). There were 123 (23.5%) patients with the Caprini score of 0 to 4, 366 (69.8%) with scores 5 to 6, 27 (5.2%) with scores 7 to 8, and 8 (1.5%) patients with scores >8. Postoperative VTE occurred in 11 (2.1%) patients, at a median time of 9 days (range 1–30) after surgery. VTE incidence by the Caprini score was 1.9% for scores 3 to 4, 0.8% for scores 5 to 6, 3.3% for scores 7 to 8, and 13% for scores >8. The Caprini score achieved an AUC of 0.70. A Caprini score >8 was significantly predictive of VTE on multivariable analysis relative to scores 5 to 6 (odds ratio = 43.41, 95% confidence interval = 7.46–252.76, p < 0.001).

Conclusion In patients undergoing DIEP breast reconstruction, VTE incidence was highest (13%) in Caprini scores greater than eight despite chemoprophylaxis. Future studies are needed to assess the role of extended chemoprophylaxis in patients with high Caprini scores.
Risky business: voluntary sex workers as suitable victims of work-related crimes in a legalised prostitution environment
Authors: Molnar Lorena , Aebi Marcelo F.
Published: February 2023

Many studies have analysed the violence to which sex workers (SWs) are exposed in countries where prostitution is criminalised, but violence in sex work when it is a legal and freelance activity has seldom been studied. This study is based on non-systematic participant observation and 14 interviews conducted with cisgender and transgender freelance SWs exercising their profession in Switzerland. Findings show that all the participants had been victims of work-related offences and that their victimisation can be interpreted through the updated version of Routine Activities Theory. Few reported the victimisation to the police although in general, they said that they appreciated the Swiss police. Most common perpetrators were customers, passers-by, and colleagues. The places where offences occurred can be defined as risky settings. The police, the SWs themselves and other actors such as social workers are identified as controllers, while the legal framework and NGOs themselves can be labelled as super-controllers. Our study suggests that public policies should not be limited simply to regulating prostitution, but also continuing to ensure SW’s safety by developing evidence-based prevention strategies.
The effects of the aesthetics and composition of hotels’ digital photo images on online booking decisions
Authors: Cuesta-Valiño Pedro , Kazakov Sergey , Gutiérrez-Rodríguez Pablo , Rua Orlando Lima
Published: February 2023

Photographic images help customers perceive product information more accurately and clearly. A customer’s perception of a particular product also influences their decision to purchase it. In the context of a hotel, guests evaluate digital hotel photos online during their booking decision process. While a large body of research has contributed to the understanding of how hotel online digital images shape hotel customer behaviour, little is known about the aesthetics, content, and composition of hotel images and their effects on booking decisions. In addition, previous research has routinely been criticised for having methodological limitations. These studies have routinely used surveys and experiments to explore how hotel pictures affect customer perception of the hotel and his/her booking intentions. Unlike prior studies, this research scopes a determination of the ‘selling’ properties pertinent to the hotel’s digital images placed online on the hotel-themed websites with the application of the latest technologies pursuant to visual data mining, processing and analysis. This study employed Google’s Inception v3 neural network as an AI solution for embedding and classifying hotel photo images with the further application of logistic regression and fuzzy cognitive mapping method. The results of the present study determined the hotel picture properties that may engender positive customer perception of the hotel and sequentially can precipitate hotel booking. The revealed ‘selling’ hotel image properties comprise (a) light and time of the photo shooting, (b) image colour scheme, (c) human presence, and (d) shooting angle. This study suggests a set of practical recommendations to hotel marketers to develop ‘selling’ photo images that generate hotel bookings online. The completed research is one of the first in the nascent literature stream in AI-powered computer vision solutions studies to determine the effects of photo aesthetics on online hotel bookings.
CRISPR-Cas9 examined for potential and challenges treating Duchenne Muscular Dystrophy
Authors: Shapiro Maura
Published: February 2023

Gene editing treatments are a promising solution to rare genetic diseases, but still face significant obstacles to implementation.
Charge conjugation approach to scattering for the Hartree type Dirac equations with chirality
Authors: Cho Yonggeun , Hong Seokchang , Ozawa Tohru
Published: February 2023

We study the Cauchy problems for the Hartree-type nonlinear Dirac equations with Yukawa-type potential derived from the pseudoscalar field. We establish scattering for large data but with a relatively small part of the initial data associated with charge conjugation by exploiting the null structure induced by the chiral operator.
Predicting the cascading dynamics in complex networks via the bimodal failure size distribution
Authors: Zhong Chongxin , Xing Yanmeng , Fan Ying , Zeng An
Published: February 2023

Cascading failure as a systematic risk occurs in a wide range of real-world networks. Cascade size distribution is a basic and crucial characteristic of systemic cascade behaviors. Recent research works have revealed that the distribution of cascade sizes is a bimodal form indicating the existence of either very small cascades or large ones. In this paper, we aim to understand the properties and formation characteristics of such bimodal distribution in complex networks and further predict the final cascade size. We first find that the bimodal distribution is ubiquitous under certain conditions in both synthetic and real networks. Moreover, the large cascades distributed in the right peak of bimodal distribution are resulted from either the failure of nodes with high load at the first step of the cascade or multiple rounds of cascades triggered by the initial failure. Accordingly, we propose a hybrid load metric (HLM), which combines the load of the initial broken node and the load of failed nodes triggered by the initial failure, to predict the final size of cascading failures. We validate the effectiveness of HLM by computing the accuracy of identifying the cascades belonging to the right and left peaks of the bimodal distribution. The results show that HLM is a better predictor than commonly used network centrality metrics in both synthetic and real-world networks. Finally, the influence of network structure on the optimal HLM is discussed.
Toward surface-enhanced Raman scattering using electroless substrate for trace arsenic detection and speciation
Authors: Adier Marie , Jurdyc Anne-Marie , Hurel Charlotte , Goutaland François , Michalon Jean-Yves , Merlen Alexandre , Dussardier Bernard , Vouagner Dominique
Published: February 2023

Arsenic is one of the most toxic elements present in the environment, especially in water. The World Health Organization (WHO) recommends a maximum concentration of arsenic in drinkable water of 10 μg/l (10 ppb). Sensors implementing Surface Enhanced Raman Scattering (SERS) can detect chemical species at low concentrations. The aim of this study is to compare two kinds of silver-coated SERS substrates for detection and speciation of trace, trivalent and pentavalent, inorganic arsenic compounds. One type of substrate was prepared by a classical thermal evaporation technique, and the second type by an electroless process. The thermally evaporated substrates allowed the detection of As(III) only, at a limit of detection (LOD) of approximately 50 mg/l, whereas As(V) could not be detected at any analyte concentration. The electroless substrates allow one to differentiate As(III) and As(V) with a LOD 1 μg/l (1 ppb) equal for each valency, below the WHO recommendation. The electroless substrates show a very large sensitivity across up to five orders of magnitude in terms of analyte concentration. Although the SERS intensity shows a nonlinear behavior over this range of concentrations, these preliminary results are encouraging in the framework of the demonstration of trace As SERS sensors in drinkable water.
Exactly solvable piecewise analytic double well potential VD(x) = min[(x + d)2, (x − d)2] and its dual single well potential VS(x) = max[(x + d)2, (x − d)2]
Authors: Sasaki Ryu
Published: February 2023

By putting two harmonic oscillator potentials x2 side by side with a separation 2d, two exactly solvable piecewise analytic quantum systems with a free parameter d > 0 are obtained. Due to the mirror symmetry, their eigenvalues {E} for the even and odd parity sectors are determined exactly as the zeros of certain combinations of the confluent hypergeometric function F11 of d and E, which are common to VD and VS but in two different branches. The eigenfunctions are the piecewise square integrable combinations of F11, the so-called U functions. By comparing the eigenvalues and eigenfunctions for various values of the separation d, vivid pictures unfold showing the tunneling effects between the two wells.
Gain recovery dynamics in active type-II semiconductor heterostructures
Authors: Schäfer F. , Stein M. , Lorenz J. , Dobener F. , Ngo C. , Steiner J. T. , Fuchs C. , Stolz W. , Volz K. , Meier T. , Hader J. , Moloney J. V. , Koch S. W. , Chatterjee S.
Published: February 2023

Type-II heterostructures as active layers for semiconductor laser devices combine the advantages of a spectrally broad, temperature stable, and efficient gain with the potential for electrical injection pumping. Their intrinsic charge carrier relaxation dynamics limit the maximum achievable repetition rates beyond any constraints of cavity design or heat dissipation. Of particular interest are the initial build up of gain after high-energy injection and the gain recovery dynamics following depletion through a stimulated emission process. The latter simulates the operation condition of a pulsed laser or semiconductor optical amplifier. An optical pump pulse injects hot charge carriers that eventually build up broad spectral gain in a model (Ga,In)As/GaAs/Ga(As,Sb) heterostructure. The surplus energies of the optical pump mimic the electron energies typical for electrical injection. Subsequently, a second laser pulse tuned to the broad spectral gain region depletes the population inversion through stimulated emission. The spectrally resolved nonlinear transmission dynamics reveal gain recovery times as fast as 5 ps. These data define the intrinsic limit for the highest laser repetition rate possible with this material system in the range of 100 GHz. The experimental results are analyzed using a microscopic many-body theory identifying the origins of the broad gain spectrum.
Studies on ion flow dynamics in a disk-shaped inertial electrostatic confinement fusion device under the influence of a triple grid arrangement
Authors: Saikia L. , Bhattacharjee D. , Mohanty S. R. , Adhikari S.
Published: February 2023

The basic interest of studying the ion flow dynamics in a disk-shaped inertial electrostatic confinement fusion (IECF) device is to achieve an explicit condition where large fusion products are possible from such a portable device, and then, it can be used for a wide range of applications. We modified the existing IECF device by introducing two external grids along with the central grid and investigated the plasma properties using the Langmuir probe technique at different operating voltages in this new configuration of the device. By taking measurements of the plasma properties throughout the chamber, the device is optimized for better ion confinement and ion flow behavior. A well-established comparison of plasma properties, such as ion density and potential in this new arrangement, has been carried out with the single-gridded IECF system. The triple grid arrangement switches to a lower working pressure region, and hence high energetic ion beams are procured. Because of the different discharge mechanisms, variations in plasma potential profile and ion confinement processes are observed when compared to the single-gridded IECF device.
Scalable selective absorber with quasiperiodic nanostructure for low-grade solar energy harvesting
Authors: Xu Zifu , Li Ying , Gao Gang , Xie Fei , Ju Ran , Yu Shimin , Liu Kaipeng , Li Jiaxin , Wang Wuyi , Li Wei , Li Tianlong , Qiu Cheng-Wei
Published: February 2023

Although the solar-thermal technology has opened up a potential green energy harvesting method, it is challenging to suppress the non-negligible energy dissipation while maintaining a high absorbance. Most disordered organic polymers are almost incapable of limiting the absorption in the desired cutoff wavelength range, which is detrimental to the design of selective absorbers. Moreover, the development of absorbers with a periodic plasmonic nanostructure is always lacking in cost-effective scalability. Herein, we report a scalable selective absorber with a quasiperiodic nanostructure composed by an economical widespread surface self-assembly of densely arranged Fe3O4 nano-particles, possessing a high-performance energy conversion for low-grade solar energy. By investigating the scale effect of the quasiperiodic densely arranged plasmonic nanostructure, a significant solar absorption >94% and ideal passive suppression of thermal emissivity <0.2 can be obtained simultaneously. With the synergy of material properties, thermal management, and environmental effect, a flexible planar solar thermoelectric harvester is demonstrated under natural sunlight (AM1.5G), reaching a significant sustaining open-circuit voltage of >20 mV/cm2, without a heat sink. This highly versatile strategy is expected to lead the exploration of energy evolution in fundamental research and pioneer next-generation, high-performance, economical, and practical solar co-harvesting systems.
Vaccination dilemma in the thermodynamic limit
Authors: Benjamin Colin , U. M. Arjun Krishnan
Published: February 2023

The vaccination game is a social dilemma that refers to the conundrum individuals face (to get immunized or not) when the population is exposed to an infectious disease. The model has recently gained much traction due to the COVID-19 pandemic since the public perception of vaccines plays a significant role in disease dynamics. This paper studies the vaccination game in the thermodynamic limit with an analytical method derived from the 1D Ising model called Nash equilibrium mapping. The individual dilemma regarding vaccination comes from an internal conflict wherein one tries to balance the perceived advantages of immunizing with the apparent risks associated with vaccination, which they hear through different news media. We compare the results of Nash equilibrium (NE) mapping from other 1D Ising-based models, namely, Darwinian evolution (DE) and agent-based simulation. This study aims to analyze the behavior of an infinite population regarding what fraction of people choose to vaccinate or not vaccinate. While Nash equilibrium mapping and agent-based simulation agree mostly, DE strays far from the two models. DE fails to predict the equilibrium behavior of players in the population reasonably. We apply the results of our study to analyze the AstraZeneca (AZ) COVID-19 vaccine risk vs disease deaths debate, both via NE mapping and the agent-based method. Both predict nearly 100% AZ vaccine coverage for people aged above 40, notwithstanding the risk. At the same time, younger people show a slight reluctance. We predict that while government intervention via vaccination mandates and/or advertisement campaigns are unnecessary for the older population, for the younger population (ages: 20–39), some encouragement from the government via media campaigns and/or vaccine mandates may be necessary.
Direct measurement of electrocaloric effect based on multi-harmonic lock-in thermography
Authors: Iguchi Ryo , Fukuda Daisuke , Kano Jun , Teranishi Takashi , Uchida Ken-ichi
Published: February 2023

We report on a direct measurement method for electrocaloric effects, the heating/cooling upon application/removal of an electric field in dielectric materials, based on a lock-in thermography technique. By use of sinusoidal excitation and multi-harmonic detection, the actual temperature change can be measured by a single measurement in the frequency domain even when the electrocaloric effect shows a nonlinear response to the excitation field. We demonstrated the method by measuring the temperature dependence of the electric-field-induced temperature change in two Sr-doped BaTiO3 systems with different ferroelectric-paraelectric phase transition temperatures, where we introduce the procedure for extracting the pure electrocaloric contribution free from heat losses and Joule heating due to leakage currents. This method can be used irrespective of the type of dielectric material and enables simultaneous estimation of the polarization change and power dissipation during the application of an electric field, making it a convenient imaging measurement method for the electrocaloric effect.
Collision-induced three-body polarizability of helium
Authors: Lang J. , Przybytek M. , Lesiuk M. , Jeziorski B.
Published: February 2023

We present the first-principles determination of the three-body polarizability and the third dielectric virial coefficient of helium. Coupled-cluster and full configuration interaction methods were used to perform electronic structure calculations. The mean absolute relative uncertainty of the trace of the polarizability tensor, resulting from the incompleteness of the orbital basis set, was found to be 4.7%. Additional uncertainty due to the approximate treatment of triple and the neglect of higher excitations was estimated at 5.7%. An analytic function was developed to describe the short-range behavior of the polarizability and its asymptotics in all fragmentation channels. We calculated the third dielectric virial coefficient and its uncertainty using the classical and semiclassical Feynman–Hibbs approaches. The results of our calculations were compared with experimental data and with recent Path-Integral Monte Carlo (PIMC) calculations [Garberoglio et al., J. Chem. Phys. 155, 234103 (2021)] employing the so-called superposition approximation of the three-body polarizability. For temperatures above 200 K, we observed a significant discrepancy between the classical results obtained using superposition approximation and the ab initio computed polarizability. For temperatures from 10 K up to 200 K, the differences between PIMC and semiclassical calculations are several times smaller than the uncertainties of our results. Except at low temperatures, our results agree very well with the available experimental data but have much smaller uncertainties. The data reported in this work eliminate the main accuracy bottleneck in the optical pressure standard [Gaiser et al., Ann. Phys. 534, 2200336 (2022)] and facilitate further progress in the field of quantum metrology.
A perspective on the device physics of lead halide perovskite semiconducting detector for gamma and x-ray sensing
Authors: Shrestha Shreetu , Tsai Hsinhan , Nie Wanyi
Published: February 2023

Metal-halide perovskites are emerging materials for radiation sensing featuring high absorption cross section, high charge mobility, and long carrier lifetime enabling superior detection efficiencies even at room temperature. Perovskite detector technologies are more complex involving different detecting modes and device architectures. To elucidate the working principles, we provide a Perspective on the device structures and the operational principles of halide perovskite direct conversion detectors for radiation sensing. We will first discuss different detection modes and introduce the commonly used device architectures and their working principles. Based on our work and pioneer developments in the field, we will next compare the performances of the reported detectors. Additionally, we will summarize the single crystal detectors and polycrystalline thin film devices and discuss their advantages and disadvantages for different applications. Finally, we provide a future Perspective on the critical problems that must be addressed to commercialize this technology.
Reconfigurable dielectric resonators with imbedded impedance surfaces—From enhanced and directional to suppressed scattering
Authors: Jacobsen Rasmus E. , Lavrinenko Andrei V. , Arslanagić Samel
Published: February 2023

Resonant elements play a vital role in tailoring of the radiation and scattering properties of devices, such as antennas and functional material platforms. We presently demonstrate a simple resonator that supports a multitude of scattering states. The resonator is a hybrid structure consisting of a finite-height dielectric cylinder integrated with a concentric impedance surface. Given its simple configuration, we apply the classical Lorentz–Mie theory to analyze its scattering properties analytically. Through a careful tuning of its geometry, the resonator is found to support enhanced and directive scattering states as well as the suppressed scattering states also known as anapole states. A prototype of the resonator has been built and tested at microwave frequencies. It utilizes water as the dielectric and a metallic tube with periodic slits as the impedance surface. Exploiting the flexibility of water, the design is easily reconfigured for different scattering responses: fully filled, the resonator is found to scatter predominantly in the forward direction, whereas an anapole state emerges with significant reduction of scattering when the resonator is partially filled with water. Consequently, the proposed resonator may be of great interest within the broad area of antenna design and functional material platforms, encompassing not only the obvious microwave frequencies but also the THz- and optical domain using high-permittivity dielectrics and graphene/nano-particle surfaces.
Corrigendum to: Altered mixed-severity fire regime has homogenised montane forests of Jasper National Park
Authors: Chavardès Raphaël D. , Daniels Lori D.
Published: February 2023

Fire suppression has altered the historical mixed-severity fire regime and homogenised forest structures in Jasper National Park, Canada. We used dendrochronology to reconstruct fire history and assess forest dynamics at 29 sites in the montane forests. Based on fire scars and even-aged post-fire cohorts, we determined 18 sites had mixed-severity fire histories through time, and 11 sites had evidence of high-severity fires only – yielding a mixed-severity fire regime for the study area. Lodgepole pine, hybrid spruce and Douglas-fir established simultaneously after low- and high-severity fires. Regardless of fire history, forest canopies were mixed in composition and subcanopies were strongly dominated by shade-tolerant hybrid spruce. Despite their size, subcanopy trees were similar in age to the canopy trees. Current stand composition and age structures largely reflect the effects of high-severity fires that burned ~110 years ago at 18 of 29 sites. In the absence of fires after 1905, forests have matured simultaneously, homogenising the landscape and resulting in forest structures that are more conducive to high-severity fire than are fires of a range of severities. Proactive fire management is justified to restore fire as a vital ecological process and promote forest resilience by countering the effects of a century of fire suppression.