bluuebunny/crossref_metadata_2025_split huggingface dataset:
Signatures of optical phase transitions in superradiant and subradiant atomic arrays
Authors: Parmee Christopher D. , Ruostekoski Janne 
Published: November 2020

AbstractResonant light interacting with matter supports different phases of a polarisable medium, and optical bistability where two phases coexist. Such phases have previously been actively studied in cavities. Here, we identify signatures of optical phase transitions and optical bistability mapped onto scattered light in free-space planar arrays of cold atoms. Methods on how to explore such systems in superradiant and extreme subradiant states are proposed. The cooperativity threshold and intensity regimes for the intrinsic optical bistability, supported by resonant dipole-dipole interactions alone, are derived in several cases of interest analytically. Subradiant states require lower intensities, but stronger cooperativity for the existence of non-trivial phases than superradiant states. The transmitted light reveals phase transitions and bistability that are predicted by mean-field theory as large jumps in coherent and incoherent signals and hysteresis. In the quantum solution, traces of phase transitions are identified in enhanced quantum fluctuations of excited level populations.
Distinct influences of large-scale circulation and regional feedbacks in two exceptional 2019 European heatwaves
Authors: Sousa Pedro M. , Barriopedro David , García-Herrera Ricardo , Ordóñez Carlos , Soares Pedro M. M. , Trigo Ricardo M. 
Published: November 2020

AbstractTwo separate heatwaves affected western Europe in June and July 2019, in particular France, Belgium, the Netherlands, western Germany and northeastern Spain. Here we compare the European 2019 summer temperatures to multi-proxy reconstructions of temperatures since 1500, and analyze the relative influence of synoptic conditions and soil-atmosphere feedbacks on both heatwave events. We find that a subtropical ridge was a common synoptic set-up to both heatwaves. However, whereas the June heatwave was mostly associated with warm advection of a Saharan air mass intrusion, land surface processes were relevant for the magnitude of the July heatwave. Enhanced radiative fluxes and precipitation reduction during early July added to the soil moisture deficit that had been initiated by the June heatwave. We show this deficit was larger than it would have been in the past decades, pointing to climate change imprint. We conclude that land-atmosphere feedbacks as well as remote influences through northward propagation of dryness contributed to the exceptional intensity of the July heatwave.
Exploring Barriers to Doctoral Education in Communication Sciences and Disorders: Insights From Practicing Professionals
Authors: Tucker Denise A. , Compton Mary V. , Allen Sarah J. , Mayo Robert , Hooper Celia , Ogletree Billy , Flynn Perry , Frazier Ashley , McMurry Summer 
Published: November 2020

Purpose
The intended purpose of this research note is to share the findings of a needs assessment online survey of speech and hearing professionals practicing in North Carolina to explore their interest in pursuing a research-focused PhD in Communication Sciences and Disorders (CSD) and to document their perceptions of barriers to pursing a PhD in CSD. In view of the well-documented shortage of doctor of philosophy (PhD) faculty to attract, retain, and mentor doctoral students to advance research and to prepare future speech and hearing professionals, CSD faculty must assess the needs, perceptions, and barriers prospective students encounter when considering pursuing a doctoral research degree in CSD.

Method
The article describes the results of a survey of 242 speech and hearing professionals to investigate their interest in obtaining an academic research-focused PhD in CSD and to solicit their perceived barriers to pursuing a research doctoral degree in CSD.

Results
Two thirds of the respondents (63.6%) reported that they had considered pursuing a PhD in CSD. Desire for knowledge, desire to teach, and work advancement were the top reasons given for pursuing a PhD in CSD. Eighty-two percent of respondents had no interest in traditional full-time study. Forty-two percent of respondents indicated that they would be interested in part-time and distance doctoral study. The barriers of time, distance, and money emerged as those most frequently identified barriers by respondents.

Conclusion
The implications inform higher education faculty on how they can best address the needs of an untapped pool of prospective doctoral students in CSD.
Spatial–temporal evolution of photospheric weak-field shifts in solar cycles 21–24
Authors: Mursula K. , Getachew T. , Virtanen I. I. 
Published: November 2020

Context. Weak magnetic field elements make a dominant contribution to the total magnetic field on the solar surface. Even so, little is known of their long-term occurrence.
Aims. We study the long-term spatial–temporal evolution of the weak-field shift and skewness of the distribution of photospheric magnetic field values during solar cycles 21−24 in order to clarify the role and relation of the weak field values to the overall magnetic field evolution.
Methods. We used Wilcox Solar Observatory (WSO) and the Synoptic Optical Long-term Investigations of the Sun Vector SpectroMagnetograph synoptic maps to calculate weak-field shifts for each latitude bin of each synoptic map, and thereby constructed a time–latitude butterfly diagram for shifts. We also calculated butterfly diagrams for skewness for all field values and for weak field values only.
Results. The weak-field shifts and (full-field) skewness depict a similar spatial–temporal solar cycle evolution to that of the large-scale surface magnetic field. The field distribution has a systematic non-zero weak-field shift and a large skewness already at (and after) the emergence of the active region, even at the highest resolution. We find evidence for coalescence of opposite-polarity fields during the surge evolution. This is clearly more effective at the supergranulation scale. However, a similar dependence of magnetic field coalescence on spatial resolution was not found in the unipolar regions around the poles.
Conclusions. Our results give evidence for the preference of even the weakest field elements toward the prevailing magnetic polarity since the emergence of an active region, and for a systematic coalescence of stronger magnetic fields of opposite polarities to produce weak fields during surge evolution and at the poles. We also find that the supergranulation process is reduced or turned off in the unipolar regions around the poles. These observations improve the understanding not only of the development of the weakest magnetic field elements, but also of the dynamics of magnetic fields at large, and even of processes below the solar surface.
Regularity analysis for an abstract thermoelastic system with inertial term
Authors: Kuang Zhaobin , Liu Zhuangyi , Fernández Sare Hugo D. 
Published: November 2020

In this paper, we provide a complete regularity analysis for the following abstract thermoelastic system with inertial term
[see formula in PDF]
where A is a self-adjoint, positive definite operator on a complex Hilbert space H and
[see formula in PDF]
It is regarded as the second part of Fernández Sare et al. [J. Diff. Eqs. 267 (2019) 7085–7134]. where the asymptotic stability of this model was investigated. We are able to decompose the region E into three parts where the associated semigroups are analytic, of Gevrey classes of specific order, and non-smoothing, respectively. Moreover, by a detailed spectral analysis, we will show that the orders of Gevrey class are sharp, under proper conditions. We also show that the orders of polynomial stability obtained in Fernández Sare et al. [J. Diff. Eqs. 267 (2019) 7085–7134] are optimal.
Synthesis of Pyridiniumboranephosphonate Diesters and Related Compounds using Trityl Cation as a Borane Hydride Acceptor
Authors: Stawinski Jacek , Rachwalak Marta , Gołębiewska Justyna , Jakubowski Tomasz 
Published: November 2020

AbstractBoranephosphonate diesters react with pyridine and some tertiary amines in the presence of dimethoxytrityl chloride used as a borane­ hydride acceptor, to afford the boron-modified phosphodiester analogues containing a P-B-N structural motif. The reaction provides a convenient entry to pyridinium- and ammoniumboranephosphonates derived from the corresponding alkyl, aryl, or nucleoside boranephosphonate diesters. Some aspects of the synthetic protocol, mechanistic features related to a possible intermediate involved, and the role of the solvents used, are discussed.
Synthesis of Azido Acids and Their Application in the Preparation of Complex Peptides
Authors: Moreira Ryan , Noden Michael , Taylor Scott D. 
Published: November 2020

AbstractAzido acids are important synthons for the synthesis of complex peptides. As a protecting group, the azide moiety is atom-efficient, easy to install and can be reduced in the presence of many other protecting groups, making it ideal for the synthesis of branched and/or cyclic peptides. α-Azido acids are less bulky than urethane-protected counterparts and react more effectively in coupling reactions of difficult-to-form peptide and ester bonds. Azido acids can also be used to form azoles on complex intermediates. This review covers the synthesis of azido acids and their application to the total synthesis of complex peptide natural products.1	Introduction2	Synthesis of α-Azido Acids2.1	From α-Amino Acids or Esters2.2	Via α-Substitution2.3	Via Electrophilic Azidation2.4	Via Condensation of N-2-Azidoacetyl-4-Phenylthiazolidin-	2-Thi	one Enolates with Aldehydes and Acetals2.5	Synthesis of α,β-Unsaturated α-Azido Acids and Esters3	Synthesis of β-Azido Acids3.1	Preparation of Azidoalanine and 3-Azido-2-aminobutanoic Acids3.2	General Approaches to Preparing β-Azido Acids Other Than	Azi	doalanine­ and AABA4	Azido Acids in Total Synthesis4.1	α-Azido Acids4.2	β-Azido Acids and Azido Acids Containing an Azide on the Side
Chain5	Conclusions
7P’s of life-satisfaction: a social constructionist model for the life satisfaction of religious minority groups in Kohat, Khyber Pakhtunkhwa (Pakistan)
Authors: Alam Jan 
Published: November 2020

AbstractMinority groups can, depending societal conditions, find themselves living marginalized lives in some communities. Religious-based discrimination can result in these groups feeling dejected and deprived of their basic rights, resulting in, among other things, stress and dissatisfaction. To understand and explore their life satisfaction, their plight needs to be addressed. Here, I present the findings from a qualitative study conducted in the Kohat district, involving the selection and interview of 27 participants, comprising 14 Christians, seven Hindus, and six Sikhs. Participants representing three different religious groups were purposively selected and interviewed using a semi-structured interview guide. Participants of the study included religious scholars, social activists, employees, and political representatives from these religious minorities. A thematic approach was used for data analysis, which comprises coding, categories, and thematic coding. The emerged categories were prioritized and then allocated names, each beginning with the letter “P”, under one thematic code namely, the “7P’s of life satisfaction”.
Examining the population flow network in China and its implications for epidemic control based on Baidu migration data
Authors: Wei Sheng , Wang Lei 
Published: November 2020

AbstractThis paper examines the spatial pattern of the population flow network and its implications for containing epidemic spread in China. The hierarchical and spatial subnetwork structure of national population movement networks is analysed by using Baidu migration data before and during the Chinese Spring Festival. The results show that the population flow was mainly concentrated on the east side of the Hu Huanyong Line, a national east-west division of population density. Some local hot spots of migration were formed in various regions. Although there were a large number of migrants in eastern regions, they tended to concentrate in corresponding provincial capital cities and the population movement subnetworks were affected by provincial administrative divisions. The patterns identified are helpful for the provincial government to formulate population policies on epidemic control. The movement flow from Wuhan (the city where the covid-19 outbreak) to other cities is significantly and positively correlated with the number of confirmed cases in other Chinese cities (about 70% of the population was constituted through innerprovincial movement in Hubei). The results show that the population flow network has great significance for informing the containment of the epidemic spread in the early stage. It suggests the importance for the Chinese government to implement provincial and municipal lockdown measures to contain the epidemic spread. The paper indicates that spatial analysis of population flow network has practical implications for controlling epidemic outbreaks.
Infant imitation in a third-party context
Authors: Stenberg Gunilla 
Published: November 2020

Abstract
The present study examined 17-month-olds’ imitation in a third-party context. In four experiments, the infants watched while a reliable or an unreliable model demonstrated a novel action with an unfamiliar (Experiments 1 and 3) or a familiar (Experiments 2 and 4) object to another adult. In Experiments 3 and 4, the second adult imitated the model’s novel action. Neither the familiarity of the object or whether or not the second adult copied the model’s behavior influenced the likelihood of infant imitation. Findings showed that the infants in the reliable model condition were more willing to imitate the model’s action with the unfamiliar object. The results suggest that infants take into account the reliability of a model even when the model has not directly demonstrated her reliability to the infant.
Improvement of spin polarization spatial uniformity in optically pumped atomic magnetometers based on counter-propagating pump beams and atomic diffusion
Authors: Zhao Junpeng , Liu Gang , Lu Jixi , Ding Ming , Ma Yanning , Ji Jie , Yang Ke , Ma Danyue , Xing Bozheng , Zhang Ning , Sun Chang , Han Bangcheng 
Published: November 2020

Abstract
In an optically pumped alkali vapor cell with a high density of atoms, the attenuation of the pump light generates a spatially non-uniform distribution of the electronic spin polarization of alkali atoms, which is detrimental to biomagnetism applications of magnetometers as well as the hyperpolarization of noble gas atoms. Therefore, in this study, we propose a new scheme to generate a nearly uniform, unsaturated spin polarization region based on counter-propagating pump beams and atomic diffusion. A finite element method-based simulation is used to demonstrate the three-dimensional distribution of the spin polarization in a spherical cell. The effects of cell temperature and pump light power on the homogeneity of the spin polarization are studied. The distribution of spin polarization near the center of the cell is experimentally measured and a 1 cm uniform spin polarization region is achieved in the center of the cell. The uniformity of spin polarization in the center region of the cell increased by 50% compared with single beam pumping. The advantage of our proposed scheme is that it can generate an unsaturated uniform region of spin polarization in the center of a cell using a single species of alkali atoms.
High-performance perovskite photodetectors based on CH3NH3PbBr3 quantum dot/TiO2 heterojunction
Authors: Ray Rajeev , Nakka Nagaraju , Pal Suman Kalyan 
Published: November 2020

Abstract
Organo-lead halide perovskite materials have opened up a great opportunity to develop high performance photodetectors because of their superior optoelectronic properties. The main issue with perovskite-only photodetector is severe carrier recombination. Integration of perovskite with high-conductive materials such as graphene or transition metal sulfides certainly improved the photoresponsivity. However, achieving high overall performance remains a challenge. Here, an improved photodetector is constructed by perovskite quantum dots (QDs) and atomic layer deposited ultrathin TiO2 films. The designed CH3NH3PbBr3 QD/TiO2 bilayer device displays inclusive performance with on/off ratio of 6.3 × 102, responsivity of 85 A W−1, and rise/decay time of 0.09/0.11 s. Furthermore, we demonstrate that interface plays a crucial role in determining the device current and enhance the overall performance of heterostructure photodetector through interface engineering. We believe that this work can provide a strategy to accelerate development of high-performance solution-processed perovskite photodetectors.
Simple in situ functionalization of carbon nanospheres
Authors: Patiño-Guillén Gerardo , Arceta-Lozano Alan , Falcón-Montes Jessica A , García-Díaz Esmeralda , Díaz de León Jorge Noé , Vazquez-Duhalt Rafael , Gao Guanhui , Méndez-Rojas Miguel Ángel , Campos-Delgado Jessica 
Published: November 2020

Abstract
Functionalized carbon nanospheres have been synthesized in situ via a facile chemical vapor deposition strategy, fabricated by the pyrolysis of toluene/ethanol mixtures at different percentages (0, 1, 2, 3, 4, and 5 wt% of ethanol). The as-grown nanospheres have been characterized using transmission electron microscopy, scanning electron microscopy, Raman and Fourier transform infrared spectroscopy, x-ray diffraction, nitrogen adsorption, zeta potential measurements and x-ray photoelectron spectroscopy. Results indicate that the incorporation of ethanol in the precursor solution reflected in the presence of oxygen and hydrogen functional groups, the highest functionalized nanospheres without compromising the morphology of the sample were yielded at 3 wt% concentration. These in situ added functional groups rendered the carbon nanostructures enhancedly dispersible and stable in water, avoiding post-synthesis and harsh chemicals processing; envisaging thus applications of the nanospheres in the biomedical field where hydrophilicity of the nanomaterials is mandatory.
Landau-like theory for buckling phenomena and its application to the elastica hypoarealis
Authors: Turzi Stefano S 
Published: November 2020

Abstract
Bifurcation phenomena are ubiquitous in elasticity, but their study is often limited to linear perturbation or numerical analysis since second or higher variations are often beyond an analytic treatment. Here, we review two key mathematical ideas, namely, the splitting lemma and the determinacy of a function, and show how they can be fruitfully used to derive a reduced function, named Landau expansion in the paper, that allows us to give a simple but rigorous description of the bifurcation scenario, including the stability of the equilibrium solutions. We apply these ideas to a paradigmatic example with potential applications to various softly constrained physical systems and biological tissues: a stretchable elastic ring under pressure. We prove the existence of a tricritical point and find bistability effects and hysteresis when the stretching modulus is sufficiently small. These results seem to be in qualitative agreement with some recent experiments on heart cells.
Sharp Hölder regularity for the inhomogeneous Trudinger’s equation
Authors: Diehl Nicolau M L , Urbano José Miguel 
Published: November 2020

Abstract
We show that locally bounded solutions of the inhomogeneous Trudinger’s equation

∂

t

|
u

|

p
−
2

u

−
d
i
v
|
∇
u

|

p
−
2

∇
u
=
f
∈

L

q
,
r

,
p
>
2
,

are locally Hölder continuous with exponent

γ
=
min

α

0

−

,

(

p
q
−
n

)

r
−
p
q

q

(

p
−
1

)

r

,

where α
0 denotes the optimal Hölder exponent for solutions of the homogeneous case. We provide a streamlined proof, using the full power of the homogeneity in the equation to develop the regularity analysis in the p-parabolic geometry, without any need of intrinsic scaling, as anticipated by Trudinger. The main difficulty in the proof is to overcome the lack of a translation invariance property.
A novel method for continuous blood pressure estimation based on a single-channel photoplethysmogram signal
Authors: Hu Qihan , Deng Xintao , Wang Aiguo , Yang Cuiwei 
Published: November 2020

Abstract

Objective: Currently, continuous blood pressure (BP) measurements are mostly based on multi-sensor combinations and datasets with limited BP ranges. Besides, most BP-related features derive from the photoplethysmogram (PPG) signal. The mechanism of PPG signal formation is not considered. We aimed to design a noninvasive and continuous method for estimation of BP using a single PPG sensor, which takes the mechanism of PPG signal formation into account. Approach: We prepared a dataset containing PPG signals for 294 patients from three public databases for constructing the BP estimation model. The features used in the model consisted of two types: novel features based on a multi-Gaussian model and existing features. The multi-Gaussian model fitted the different components (i.e. the main wave, the dicrotic wave and the tidal wave) of the PPG signal. Ensemble machine learning algorithms were applied to estimate systolic blood pressure (SBP) and diastolic blood pressure (DBP). When partitioning the dataset, there was an overlap between the training set and the testing set. Main results: Datasets with a wide-range of SBP and DBP values (SBP ranging from 74 to 229 mmHg and DBP ranging from 26 to 141 mmHg) were used to evaluate our method. The mean and standard deviation of error for SBP and DBP estimations were −0.21 ± 5.21 mmHg and −0.19 ± 3.37 mmHg, respectively. The model performance fully met the Association for the Advancement of Medical Instrumentation standard and was grade ‘A’ on the British Hypertension Society standard. Significance: The multi-Gaussian model could be used to estimate BP, and our method was able to track a wide range of BP accurately. In addition our method is based on a single PPG sensor, making it very convenient.
TJ cm−3 high energy density plasma formation from intense laser-irradiated foam targets composed of disordered carbon nanowires
Authors: Jiang K , Pukhov A , Zhou C T 
Published: November 2020

Abstract
High energy density plasma formation from intense laser-irradiated foam targets composed of disordered carbon nanowires is investigated using three-dimensional particle-in-cell simulations. It is shown that due to the unprecedentedly high laser energy absorption rate of the foam target, approximately three times larger as compared with simple solid targets, the plasma energy density reaches an unexplored TJ cm−3 regime at 1023 W cm−2 laser irradiation. In addition, nanowire thermal expansion caused by prepulse heating is considered. We find that after expansion, the target becomes relativistically transparent to the main pulse. The average value of particle energy density decreases slightly and its distribution tends to resemble that of solid targets. Furthermore, energy density scaling with laser intensities is given. It suggests that an even more extreme plasma state is reachable using ultraintense lasers, as the energy loss to photons caused by quantum electrodynamics effects is rather negligible.