bluuebunny/crossref_metadata_2025 huggingface dataset:
Graphene-based enhancement of near-field radiative-heat-transfer rectification
Authors: Landrieux Simon , Ben-Abdallah Philippe , Messina Riccardo
Published: April 2022

We present a thermal device based on the near-field interaction between two substrates made of a polar and a metal-insulator-transition material. As a result of the temperature dependence of the optical properties, this device acts as a thermal rectifier, implying a strong asymmetry in the heat flux when reversing the two temperatures. By covering both substrates with a graphene sheet, we show a significant enhancement of rectification coefficient. The investigation of the flux spectral properties along with its distance dependence allows us to prove that this enhancement is associated with a change in the power-law dependence of the heat flux with respect to the separation distance in the electrostatic regime due to the presence of graphene sheets. Our results highlight the promising role of graphene-based hybrid structures in the domain of nanoscale thermal management.
Investigating finite-size effects in molecular dynamics simulations of ion diffusion, heat transport, and thermal motion in superionic materials
Authors: Grasselli Federico
Published: April 2022

The effects of the finite size of the simulation box in equilibrium molecular dynamics simulations are investigated for prototypical superionic conductors of different types, namely, the fluorite-structure materials PbF2, CaF2, and UO2 (type II), and the α phase of AgI (type I). Largely validated empirical force-fields are employed to run ns-long simulations and extract general trends for several properties, at increasing size and in a wide temperature range. This work shows that, for the considered type-II superionic conductors, the diffusivity dramatically depends on the system size and that the superionic regime is shifted to larger temperatures in smaller cells. Furthermore, only simulations of several hundred atoms are able to capture the experimentally observed, characteristic change in the activation energy of the diffusion process, occurring at the order–disorder transition to the superionic regime. Finite-size effects on ion diffusion are instead much weaker in α-AgI. The thermal conductivity is found generally smaller for smaller cells, where the temperature-independent (Allen-Feldman) regime is also reached at significantly lower temperatures. The finite-size effects on the thermal motion of the non-mobile ions composing the solid matrix follow the simple law that holds for solids.
Construing FL writers’ meaning-making choices in a historical recount genre in Spanish
Authors: Sheldon Elena
Published: April 2022

This study reports on a four-semester teaching programme for foreign language (FL) intermediate writing abilities
in Spanish to be implemented in educational practice. The study conducts qualitative analysis, drawing on systemic functional
linguistics (SFL), of developmental changes in twenty undergraduate, Spanish Level 4 students, based on their performance of, and
comments on, pre- and post-instructional written tasks, focusing on meaning-making choices in the construction of a historical
recount genre over one semester of instruction at an Australian university. Responding to the need for research on academic
writing in FL, the paper shows that SFL facilitates students’ understanding of writing development in an FL as they explore
textual, ideational and interpersonal meanings in conjunction with required lexicogrammatical choices to fulfil the rhetorical
demands of this genre.
The embodiment of language
Authors: Korner Anthony
Published: April 2022

In this paper an understanding of psychotherapeutic conversation is outlined emphasising whole-body functioning. The underpinning of conversation by both Central and Autonomic Nervous Systems (CNS & ANS) and evolutionary developments that support social engagement and language are considered. An idea will be taken up that for psychotherapy, language needs to be understood within each patient as more than meets the eye, rather than less, providing a potential for exchanges in the therapeutic conversation that enhance the growth of self for each individual. The notion ofculminativepatterns of communicative interaction speaks to this growth and the enhancement of a sense of meaning in personal contexts. This goes beyond an analytic approach, implying synthesis, integration and growing coherence over time. Human development is towards social engagement, building upon a capacity for relations that are rewarding to the parties involved (Meares 2016). The problem of responding to embodied communication in psychotherapy is considered in relation to moments of meeting, seen as mutative in therapy. Each person is anembodied textwith potential for elaboration, re-shaping and discovery. Clinical illustrations are provided, demonstrating a linguistic model of therapeutic growth and an experimental method that provides a window onto the exchange characteristics of language. To close, the problem of systematising embodiment and its relation to the conversation is considered, along with the implications for therapy and future research, integrating linguistics and interactive functional measures of the body.
Non-linear waves of a surface charge in a cold plasma with an inhomogeneous transition layer on the boundary
Authors: Gradov O M
Published: April 2022

The properties of nonlinear wave formations of the surface charge, the parameters of which oscillate in time, as well as also other perturbations, the temporal evolution of which is not carried out according to the harmonic law, are considered in the approximation of the inhomogeneous transition layer at the boundary of a cold plasma. A single equation for one of the related parameters of a nonlinear process is obtained, which allows to take into account the influence of an inhomogeneous transition layer, which leads in a linear approximation to the resonant absorption and spatial dispersion of surface oscillations. New forms of nonlinear waves of surface charge have been analyzed.
A pure dielectric metamaterial absorber with broadband and thin thickness based on a cross-hole array structure
Authors: Cao Wenbo , Wen Youquan , Jiang Chao , Yu Yantao , Wang Yiyu , Ma Zheyipei , Zhao Zixiang , Wang Lanzhi , Huang Xiaozhong
Published: April 2022

A pure dielectric metamaterial absorber with broadband and thin thickness is proposed, whose structure is designed as a periodic cross-hole array. The pure dielectric metamaterial absorber with high permittivity is prepared by ceramic reinforced polymer composites. Compared with those with low permittivity, the absorber with high permittivity is more sensitive to structural parameters, which means that it is easier to optimize the equivalent electromagnetic parameters and achieve wide impedance matching by altering the size or shape of the unit cell. The optimized metamaterial absorber exhibits reflection loss below −10 dB in 7.93 GHz–35.76 GHz with a thickness of 3.5 mm, which shows favorable absorption properties under the oblique incidence of TE polarization (±45°). Whether it is a measured or simulated value, the strongest absorbing peak reaches below −45 dB, which exceeds that of most metamaterial absorbers. The distributions of power loss density and electric and magnetic fields are investigated to study the origin of their strong absorbing properties. Multiple resonance mechanisms are proposed to explain the phenomenon, including polarization relaxation of the dielectric and edge effects of the cross-hole array. This work overcomes the shortcomings of the narrow absorbing bandwidth of dielectrics. It demonstrates that the pure dielectric metamaterial absorber with high permittivity has great potential in the field of microwave absorption.
Electron delocalization enhances the thermoelectric performance of misfit layer compound (Sn1−x
Bi
x
S)1.2(TiS2)2
Authors: Zhao Xin , Zhao Xuanwei , Lin Liwei , Ren Ding , Liu Bo , Ang Ran
Published: April 2022

The misfit layer compound (SnS)1.2(TiS2)2 is a promising low-cost thermoelectric material because of its low thermal conductivity derived from the superlattice-like structure. However, the strong covalent bonds within each constituent layer highly localize the electrons thereby it is highly challenging to optimize the power factor by doping or alloying. Here, we show that Bi doping at the Sn site markedly breaks the covalent bonds networks and highly delocalizes the electrons. This results in a high charge carrier concentration and enhanced power factor throughout the whole temperature range. It is highly remarkable that Bi doping also significantly reduces the thermal conductivity by suppressing the heat conduction carried by phonons, indicating that it independently modulates phonon and charge transport properties. These effects collectively give rise to a maximum ZT of 0.3 at 720 K. In addition, we apply the single Kane band model and the Debye–Callaway model to clarify the electron and phonon transport mechanisms in the misfit layer compound (SnS)1.2(TiS2)2.
Enhanced and tunable circular dichroism in the visible waveband by coupling of the waveguide mode and local surface plasmon resonances in double-layer asymmetric metal grating
Authors: Wang Liu-Li , Gu Yang , Chen Yi-Jing , Ni Ya-Xian , Dong Wen
Published: April 2022

Circular dichroism (CD) has shown very interesting possibilities as a means to characterize the chiral signal of a chiral structure. Here, we theoretically demonstrated enhanced and tunable CD in the visible light regime using a composite structure consisting of a double-layer metal grating gaped by a dielectric waveguide layer. Based on the coupling of the waveguide modes and the localized plasmonic resonances, the CD could reach a maximum value as high as 0.52 at 635 nm, which is four times higher than the CD value obtained in a conventional double-layer grating without the waveguide coupling effect. Furthermore, the spectral positions of the enhanced CD bands could be easily tuned by controlling the structural parameters. The proposed hybrid double-grating and waveguide structures could have potential applications in chiral selective imaging, sensing and spectroscopy, especially where the transmission measurement is required.
Design of a low-frequency miniaturized piezoelectric antenna based on acoustically actuated principle
Authors: Zhang Yong , Yan Zhong-Ming , Han Tian-Hao , Zhu Shuang-Shuang , Wang Yu , Zhou Hong-Cheng
Published: April 2022

An acoustically actuated piezoelectric antenna is proposed for low frequency (LF) band in this paper. The proposed antenna is theoretically calculated, numerically optimized by the finite element method (FEM), and experimentally analyzed. The measurement results show that the near-field radiation pattern of the piezoelectric antenna is similar to that of the electric dipole antenna. The radiation efficiency of the piezoelectric antenna is 3–4 orders of magnitude higher than that of electrically small antenna (ESA), with their sizes being the same size, and the maximum transmission distance obtained experimentally is 100 cm, which can be improved by increasing the input power. In addition, the gain, directivity, and quality factor of piezoelectric antenna are also analyzed. In this paper, traditional antenna parameters are creatively used to analyze the performance of piezoelectric antenna. The research conclusions can provide reliable theoretical basis for realizing LF antenna miniaturization.
A band-pass frequency selective surface with polarization rotation
Authors: Lin Bao-Qin , Huang Wen-Zhun , Guo Jian-Xin , Liu Zhe , Wang Yan-Wen , Ye Hong-Jun
Published: April 2022

A band-pass frequency selective surface (FSS) with polarization rotation property is proposed. The proposed polarization rotating FSS (PR-FSS) is a two-dimensional periodic structure, its unit cell is an antenna-filter-antenna (AFA) module, and the polarization directions of the upper and lower antennas in each AFA module are orthogonal to each other, so the PR-FSS can achieve frequency selection and 90 degrees polarization rotation at the same time. The numerical simulation demonstrate that the anticipated frequency selection and polarization rotation are realized by the PR-FSS in the frequency band from 8.84 GHz to 10.30 GHz with a relative bandwidth of 15.26%, and the maximum insertion loss in the pass band is only 0.17 dB. Finally, one effective experiment validation is carried out, a reasonable agreement is observed between the experimental and simulated results except for a slight deviation caused by fabrication error and measurement tolerance.
Nonreciprocal coupling induced entanglement enhancement in a double-cavity optomechanical system
Authors: Liu Yuan-Yuan , Zhang Zhi-Ming , Liu Jun-Hao , Wang Jin-Dong , Yu Ya-Fei
Published: April 2022

We investigate the quantum entanglement in a double-cavity optomechanical system consisting of an optomechanical cavity and an auxiliary cavity, where the optomechanical cavity mode couples with the mechanical mode via radiation-pressure interaction, and simultaneously couples with the auxiliary cavity mode via nonreciprocal coupling. We study the entanglement between the mechanical oscillator and the cavity modes when the two cavities are reciprocally or nonreciprocally coupled. The logarithmic negativity

E
n

(
1
)

(

E
n

(
2
)

) is adopted to describe the entanglement degree between the mechanical mode and the optomechanical cavity mode (the auxiliary cavity mode). We find that both

E
n

(
1
)

and

E
n

(
2
)

have maximum values in the case of reciprocal coupling. By using nonreciprocal coupling,

E
n

(
1
)

and

E
n

(
2
)

can exceed those maximum values, and a wider detuning region where the entanglement exists can be obtained. Moreover, the entanglement robustness with respect to the environment temperature is also effectively enhanced.
Numerical study of converting beat-note signals of dual-frequency lasers to optical frequency combs by optical injection locking of semiconductor lasers
Authors: Liu Chenhao , Jin Haoshu , Liu Hui , Bai Jintao
Published: April 2022

The optical injection locking of semiconductor lasers to dual-frequency lasers is studied by numerical simulations. The beat-note signals can be effectively transformed to optical frequency combs due to the effective four wave-mixing in the active semiconductor gain medium. The low-noise Gaussian-like pulse can be obtained by locking the relaxation oscillation and compensating the gain asymmetry. The simulations suggest that pulse trains of width below 30 ps and repetition rate in GHz frequency can be generated simply by the optical injection locking of semiconductor lasers. Since the optical injection locking can broaden the spectrum and amplify the optical power simultaneously, it can be a good initial stage for generating optical frequency combs from dual-frequency lasers by multi-stage of spectral broadening in nonlinear waveguides.
Metallic ion-based graphene oxide functionalized silk fibroin-based dressing promotes wound healing via improved bactericidal outcomes and faster re-epithelization
Authors: Gupta Sharda , Prasad Pushpa , Roy Amit , Alam Mohammad Mahtab , Ahmed Irfan , Bit Arindam
Published: April 2022

An ideal wound dressing material should enhance the wound healing process and must avoid bacterial contamination. In this study, the synergistic effect of graphene oxide (GO), silver (Ag) and magnesium (Mg) based silk electrospun nanofibrous film on wound healing was evaluated. It reports the influence of essential elements Mg and Ag during the skin regeneration process. Silver and magnesium nanoparticles were doped in graphene oxide. The goal of the present study was to fabricate an electrospun nanofibrous patch with nanoscale fillers to improve the wound recuperation manner and decrease the recuperation time to forestall microorganism infections and improve cellular behavior. Doping was done to insert Ag+ and Mg2+ ions in the crystal lattice of GO to overcome the disadvantage of aggregation of Ag and Mg nanoparticles. In this study, Mg2+ and Ag+ ions doped GO functionalized silk fibroin/PVA dressing material was prepared using the electrospinning technique. It was found that, Mg-GO@NSF/PVA and Ag/Mg-GO@NSF/PVA film possess good cytocompatibility, low hemolytic effect and effective antibacterial and anti-biofilm activities. Furthermore, their improved hydrophilicity and mid-range water vapor transmission rate allow them to be a suitable wound dressing material. Tensile strength of the composite silk film were enhanced relatively to silk/PVA film. The effect of prepared film on wound repair were investigated in excision rat model. It indicates, the wound covered with Ag/Mg-GO@NSF/PVA film showed the highest wound contraction rate and re-epithelization, allowing faster repair of wound sites. In conclusion, the development of metallic ions doped GO based silk fibroin/PVA is a promising approach towards development of antibiotic free wound dressing material. It prevents anti-biofilm formation and also provides adequate therapeutic effects for accelerating wound healing.
Climate regulation ecosystem services and biodiversity conservation are enhanced differently by climate- and fire-smart landscape management
Authors: Campos João C , Rodrigues Sara , Sil Ângelo , Hermoso Virgilio , Freitas Teresa R , Santos João A , Fernandes Paulo M , Azevedo João C , Honrado João P , Regos Adrián
Published: April 2022

The implementation of climate-smart policies to enhance carbon sequestration and reduce emissions is being encouraged worldwide to fight climate change. Afforestation practices and rewilding initiatives are climate-smart examples suggested to tackle these issues. In contrast, fire-smart approaches, by stimulating traditional farmland activities or agroforestry practices, could also assist climate regulation while protecting biodiversity. However, there is scarce information concerning the potential impacts of these alternative land management strategies on climate regulation ecosystem services and biodiversity conservation. As such, this work simulates future effects of different land management strategies in the Transboundary Biosphere Reserve of Meseta Ibérica (Portugal-Spain). Climate-smart (‘Afforestation’, ‘Rewilding’) and fire-smart (‘Farmland recovery’, ‘Agroforestry recovery’) scenarios were modelled over a period of 60 years (1990–2050), and their impacts on climate regulation services were evaluated. Species distribution models for 207 vertebrates were built and future gains/losses in climate-habitat suitability were quantified. Results suggest climate-smart policies as the best for climate regulation (0.98 Mg C ha−1 yr−1 of mean carbon sequestration increase and 6801.5 M€ of avoided economic losses in 2020–2050 under Afforestation scenarios), while providing the largest habitat gains for threatened species (around 50% for endangered and critically endangered species under Rewilding scenarios). Fire-smart scenarios also benefit carbon regulation services (0.82 Mg C ha−1 yr−1 of mean carbon sequestration increase and 3476.3 M€ of avoided economic losses in 2020–2050 under Agroforestry scenarios), benefiting the majority of open-habitat species. This study highlights the main challenges concerning management policies in European rural mountains, while informing decision-makers regarding landscape planning under global change.
Recent progress on the J-TEXT three-wave polarimeter-interferometer
Authors: WANG Yuhan , GAO Li , SHI Peng , XU Xin , ZHOU Yinan , YANG Qinglong , YANG Chengyu , TAO Qinlin , SHEN Chengshuo , WANG Yajun , WANG Lu , CHEN Zhipeng , XIA Donghui , CHEN Zhongyong , WANG Nengchao , YANG Zhoujun , DING Yonghua , PAN Yuan
Published: April 2022

The J-TEXT three-wave polarimeter-interferometer system (POLARIS), which measures time-space distribution of electron density and current density, has been optimized with both the optical system and the equilibrium reconstruction method. The phase resolution of a Faraday rotation angle has been improved from 0.1 to 0.06 degree in chords from –0.18 to 0.18 m (plasma minor radius), and the sawtooth oscillation behavior has been detected by Faraday rotation angle measurement. By combining the POLARIS measured data and the equilibrium and fitting code (EFIT), an upgraded equilibrium reconstruction method has been developed, which provides a more accurate temporal and spatial distribution of current density and electron density. By means of the optimized POLARIS and improved equilibrium reconstruction, variations of profiles with increasing density have been carried out, under both Ohmic and electron cyclotron resonance heating discharges.
The limit of the inverse mean curvature flow on a torus
Authors: Harvie Brian
Published: April 2022

For an

H
>
0

H>0

rotationally symmetric embedded torus

N

0

⊂

R

3

N_{0} \subset \mathbb {R}^{3}

evolved by Inverse Mean Curvature Flow, we show that the total curvature

|

A

|

|A|

remains bounded up to the singular time

T

max

T_{\max }

. This in turn implies convergence of the

N

t

N_{t}

to a

C

1

C^{1}

rotationally symmetric embedded torus

N

T

max

N_{T_{\max }}

as

t
→

T

max

t \rightarrow T_{\max }

without rescaling, contrasting sharply with the behavior of other extrinsic flows. Later, we note a scale-invariant

L

2

L^{2}

energy estimate on any flow solution in

R

3

\mathbb {R}^{3}

that may be useful in ruling out curvature blowup near singularities more generally.
Local approximation of heterogeneous porous medium equation by some nonlocal dispersal problems
Authors: Sun Jian-Wen , Vo Hoang-Hung
Published: April 2022

The classical porous medium equation is widely used to model different natural phenomena related to diffusion, filtration and heat propagation. In this short communication, we prove that the solution of porous medium equation can be locally approximated by the solution of a class of nonlocal dispersal equation. Our work is a counterpart to the important works (see Berestycki et al. [J. Funct. Anal. 271 (2016), pp. 2701–2751; J. Math. Biol. 72 (2016), pp. 1693–1745]; Dipierro et al. [J. Eur. Math. Soc. (JEMS) 19 (2017), pp. 957–966; J. Geom. Anal. 29 (2019), pp. 1428–1455]; Hansen and Netuka [Potential Anal. 2 (1993), pp. 67–71]; Ignat and Rossi [J. Funct. Anal. 251 (2007), pp. 399–437]; Shen and Xie [J. Differential Equations 259 (2015), pp. 7375–7405]; Sprekels and Valdinoci [SIAM J. Control Optim. 55 (2017), pp. 70–93]).
Maximum number of limit cycles bifurcating from the period annulus of cubic polynomial systems
Authors: Shi Hongwei , Bai Yuzhen
Published: April 2022

This paper is devoted to the limit cycle bifurcation problem for some cubic polynomial systems, whose unperturbed systems have a period annulus and two invariant lines. Using the first order Melnikov function and Chebyshev criterion, we obtain the maximum number of limit cycles bifurcating from the period annulus. It improves a known result given by Sui and Zhao [Internat. J. Bifur. Chaos Appl. Sci. Engrg. 28 (2018), 1850063].
Patterson–Sullivan theory for Anosov subgroups
Authors: Dey Subhadip , Kapovich Michael
Published: April 2022

We extend several notions and results from the classical Patterson–Sullivan theory to the setting of Anosov subgroups of higher rank semisimple Lie groups, working primarily with invariant Finsler metrics on associated symmetric spaces. In particular, we prove the equality between the Hausdorff dimensions of flag limit sets, computed with respect to a suitable Gromov (pre-)metric on the flag manifold, and the Finsler critical exponents of Anosov subgroups.
On some topological realizations of groups and homomorphisms
Authors: Chocano Pedro J. , Morón Manuel , Ruiz del Portal Francisco
Published: April 2022

Given a homomorphism of groups

f
:
G
→
H

f:G\rightarrow H

, we construct a topological space

X
f

X_f

such that its group of homeomorphisms

A
u
t
(

X
f

)

Aut(X_f)

is isomorphic to

G
G

, its group of homotopy classes of self-homotopy equivalences

E

(

X
f

)

\mathcal {E}(X_f)

is isomorphic to

H
H

and the natural map between

A
u
t
(

X
f

)

Aut(X_f)

and

E

(

X
f

)

\mathcal {E}(X_f)

is

f
f

. In addition, we consider realization problems involving homology groups, homotopy groups and groups of automorphisms.
High Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Household Transmission Rates Detected by Dense Saliva Sampling
Authors: Kolodziej Lisa M , van Lelyveld Steven F L , Haverkort Mildred E , Mariman Rob , Sluiter-Post Judith G C , Badoux Paul , de Koff Emma M , Koole Jeffrey C D , Miellet Willem R , Swart Adriaan N , Coipan Elena C , Meijer Adam , Sanders Elisabeth A M , Trzciński Krzysztof , Euser Sjoerd M , Eggink Dirk , van Houten Marianne A
Published: April 2022

Background

Understanding the dynamics of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) household transmission is important for adequate infection control measures in this ongoing pandemic.

Methods

Households were enrolled upon a polymerase chain reaction–confirmed index case between October and December 2020, prior to the coronavirus disease 2019 vaccination program. Saliva samples were obtained by self-sampling at days 1, 3, 5, 7, 10, 14, 21, 28, 35, and 42 from study inclusion. Nasopharyngeal swabs (NPS) and oropharyngeal swabs (OPS) were collected by the research team at day 7 and capillary blood samples at day 42. Household secondary attack rate (SAR) and per-person SAR were calculated based on at least 1 positive saliva, NPS, OPS, or serum sample. Whole genome sequencing was performed to investigate the possibility of multiple independent SARS-CoV-2 introductions within a household.

Results

Eighty-five households were included consisting of 326 (unvaccinated) individuals. Comparable numbers of secondary cases were identified by saliva (133/241 [55.2%]) and serum (127/213 [59.6%]). The household SAR was 88.2%. The per-person SAR was 64.3%. The majority of the secondary cases tested positive in saliva at day 1 (103/150 [68.7%]). Transmission from index case to household member was not affected by age or the nature of their relationship. Phylogenetic analyses suggested a single introduction for the investigated households.

Conclusions

Households have a pivotal role in SARS-CoV-2 transmission. By repeated saliva self-sampling combined with NPS, OPS, and serology, we found the highest SARS-CoV-2 household transmission rates reported to date. Salivary (self-) sampling of adults and children is suitable and attractive for near real-time monitoring of SARS-CoV-2 transmission in this setting.
Complementary interactions between indirect and direct fitness in a cooperatively breeding bird
Authors: Li Zhibing , Da Xinwei , Lu Xin
Published: April 2022

Altruism is difficult to explain evolutionarily and to understand it, there is a need to quantify the benefits and costs to altruists. Hamilton’s theory of kin selection argues that altruism can persist if the costs to altruists are offset by indirect fitness payoffs from helping related recipients. Nevertheless, helping nonkin is also common and in such situations, the costs must be compensated for by direct benefits. While previous researchers tended to evaluate the indirect and direct fitness in isolation, we expect that they have a complementary interaction where altruists are associated with recipients of different relatedness within a population. The prediction is tested with 12 years of data on lifetime reproductive success for a cooperatively breeding bird, Tibetan ground tits Pseudopodoces humilis. Helpers who helped distantly related recipients gained significantly lower indirect benefits than those who helped closely related recipients, but the opposite was true for direct fitness, thereby making these helpers have an equal inclusive fitness. Helping efforts were independent of helpers’ relatedness to recipients, but those helping distantly related recipients were more likely to inherit the resident territory, which could be responsible for their high direct reproductive success. Our findings provide an explanatory model for the widespread coexistence of altruists and recipients with varying relatedness within a single population.
Linearized Bayesian estimation of magnetization and depth to magnetic bottom from satellite data
Authors: Szwillus Wolfgang , Baykiev Eldar , Dilixiati Yixiati , Ebbing Jörg
Published: April 2022

Estimating the depth to magnetic bottom (DTB) from magnetic data is one of the most important and difficult potential field inversion problems. Since DTB can often be linked to the Curie isotherm depth of magnetite (∼580 °C), it could provide crucial constraints on heat flow, even in remote or inaccessible areas. Spectral methods are the most popular approach to estimate DTB, but their reliability has been challenged on many grounds. In contrast, space-domain methods have received relatively little attention, even though they might avoid some of the limitations of spectral methods. Furthermore, many DTB estimation methods are to some extent ad hoc, which makes uncertainty estimation and effective communication of the results difficult. In this work, we develop a Bayesian approach to estimate susceptibility and DTB from magnetic data. We describe the subsurface in terms of tesseroids and use a two-step inversion procedure that consists of a Monte Carlo Markov Chain hyperparameter optimization and a linearized inversion. This way, the uncertainties due to unknown hyperparameter are rigorously propagated to the final maps of susceptibility and DTB. Additionally, pointwise constraints based on heat flow measurements can be easily included into the inversion. Synthetic tests are used to determine the accuracy and reliability of the new algorithm. We find that heat flow constraints are necessary to achieve reliable results, although already a small number of points is sufficient. Finally, we apply the algorithm to the Australian continent and demonstrate applicability to real data.
Gravity field forward modelling using tesseroids accelerated by Taylor series expansion and symmetry relations
Authors: Zeng Xianghang , Wan Xiaoyun , Lin Miao , Wang Wenbin
Published: April 2022

In this study, we developed a new method that can significantly accelerate the forward modelling of gravity fields generated by large-scale tesseroids while keeping the computational accuracy as high as possible. The cost of the high efficiency is that the method only works under the assumptions that (1) all tesseroids in the same latitude band have the same horizontal dimension, (2) the computation points are located at the same surface level and aligned with the horizontal centres of tesseroids and (3) each tesseroid has a constant or linearly varying density. The new method first integrates the kernel function of the Newton’s volume integral analytically in the radial direction to eliminate its dependence on the vertical dimension of the tesseroid, and then expands the integrated kernel function into a Taylor series up to a certain order. Because the Taylor series expansion term of the integrated kernel function is an odd or even function of the difference between the longitudes of the tesseroid and computation point, there exist shifting or swapping symmetry relations among the gravity field of tesseroids. Consequently, the shifting or swapping symmetry is extended to the tesseroids with unequal vertical dimensions. Numerical experiments using the spherical shell model are conducted to verify the effectiveness of the new method. The results show that the computational speed of the new method is about 30 times faster than that of the traditional method, which employs the Gauss–Legendre quadrature rule and a 2-D adaptive subdivision approach, while keeping almost the same computational accuracy. When applying the new method to an ice shell with unequal thicknesses, the results reveal that the relative errors of calculating V, Vz and Vzz are smaller than 10−8, 10−6 and 10−4, respectively if the Taylor series expansion is truncated at order 4, while the computational time consumed by the new method is about 7 times less than that of the traditional method. Finally, the influence of the truncation order on the computational accuracy and the strategies for dividing the latitude band into several parts to further improve the accuracy are discussed.
Molecular connections between circadian clock and health/ageing
Authors: Nakahata Yasukazu , Fukada Yoshitaka
Published: April 2022

For decades, considerable efforts have been expended for solving the molecular mechanisms of disease progression. An important clue to tackle this question is the circadian clock. Recent findings have uncovered previously unknown molecular connections between circadian clock and disease incidence, consequently causing the ageing process. Furthermore, ‘chronotherapy’ is emerging as a new concept of optimizing the time of the day for drug administration according to target gene expressions in order to maximize therapeutic efficacy and minimize the side effects. This concept will help cure patients and prevent them from suffering evitable pain and side effects. This JB special issue ‘Molecular connections between circadian clock and health/aging’ discusses how the circadian clocks link to health and ageing from molecular to organismal levels.
The quantitative characterization of hydraulic fracture connectivity from a postmortem investigation
Authors: Jayawickrama Eranga G , Muto Jun , Sasaki Osamu , Nagahama Hiroyuki
Published: April 2022

Two bio-siliceous Onnagawa (ONG I and ONG II) shale samples have been hydraulically fractured under two constant differential stresses (60 and 85 MPa, respectively) to investigate the fracture network's connectivity evolution by a postmortem analysis. The pressure inside the drilled borehole in a cylindrical core sample is increased above the confining pressure (10 MPa) until failure by hydraulic fracture. The two samples failed at two different borehole pressures (ONG I: 42 MPa, ONG II: 16 MPa). Fractured samples were scanned in an industrial X-ray CT machine and the tomographic images of the fracture network were extracted for a postmortem investigation. From the fracture volume segments, obtained by thresholding the frequency distribution of the fracture network's voxel values, a quantitative estimation of fracture connectivity was carried out. The connectivity was quantified based on the relative entropy of size distribution of fractures (${H_r}$), a method adapted from information theory. Fracture connectivity estimation shows that ${H_r}$ is at a maximum value when the fractures show a significant distribution with very limited connectivity. The value of ${H_r}$ is at a minimum and close to 0 when a well-linked fracture network is formed. In both samples, this minimum was attained at the threshold of 43k indicating the highest connectivity and the best representation of the fracture network. The extracted fracture network of ONG I showed a multi-winged hydraulic fracture network while a planar conventional two-winged hydraulic fracture network had been generated in ONG II with a lower fracture volume.
Field Occurrence and Overwintering of Oospores of Pseudoperonospora cubensis in the Southeastern United States
Authors: Kikway Isaack , Keinath Anthony P. , Ojiambo Peter S.
Published: April 2022

In the United States, the cucurbit downy mildew pathogen, Pseudoperonospora cubensis, has been shown to form oospores under laboratory conditions, but there are no reports on the formation of oospores in naturally infected cucurbit plants in the field. This study investigated the occurrence of oospores in naturally infected leaves from cucurbit fields in North Carolina and South Carolina from 2018 to 2020. Oospore viability and survival was also determined outdoors during the winter in North Carolina during this study period using soil containing leaves infested with oospores. About 5% of 1,658 naturally infected cucumber and cantaloupe leaves sampled during the study had oospores, with a mean density of 585 oospores per cm2 of infected leaf tissue. Absolute oospore viability, as assessed using the plasmolysis method, declined linearly (slope = −0.27; P < 0.0001) over the 6-month exposure period from 67.8% in November to 19.3% in May. Other variables being equal, the decrease in oospore viability was significantly affected by soil temperature (b = −0.03 to −0.05; P < 0.0001) and number of rainy days (b = 21.6 to 40.46; P < 0.05), while the effects of soil moisture on oospore viability were less clear. About 20% of the oospores exposed to outdoor conditions at the end the study period were putatively viable and deemed potentially infective. However, these putatively viable oospores failed to germinate or initiate disease when inoculated onto cucumber or cantaloupe leaves. These results indicate that oospores might require some unrecognized stimuli or physiological factors to initiate germination and infection. Nonetheless, viability of oospores at the end of the winter season suggests that once exposed to the right conditions that stimulate germination, these oospores could potentially serve as a primary inoculum source in the southeastern United States where winter temperatures are cold enough to kill cucurbits plants.
Development and Psychometric Testing of the Academic Clinical Nurse Educator Skill Acquisition Tool
Authors: Shellenbarger Teresa , Sebach Aaron M.
Published: April 2022

AIM

This article reports the development and psychometric testing of an instrument to measure academic clinical nurse educator skill acquisition.

BACKGROUND

Little research explores clinical nurse educator competence.

METHOD

Using the National League for Nursing Academic Clinical Nurse Educator core competencies and a literature review, newly created clinical nurse educator skill acquisition items underwent two rounds of content validity testing. The resulting 40-item Academic Clinical Nurse Educator Skill Acquisition Tool was pilot tested with a convenience sample of 133 clinical nurse educators.

RESULTS

The Academic Clinical Nurse Educator Skill Acquisition Tool demonstrated adequate validity and internal consistency reliability. Factor analysis identified two factors: facilitating clinical learning through the use of effective teaching, assessment, and evaluation and promoting nursing enculturation.

CONCLUSION

Further use of this tool may provide insight about the psychometrics, offer information about clinical teaching competence, and could lead to improved orientation and mentoring programs for clinical nurse educators.
Connectome Analysis in an Individual with SETD1B-Related Neurodevelopmental Disorder and Epilepsy
Authors: Weng Rosa , Nenning Karl-Heinz , Schwarz Michelle , Riedhammer Korbinian M. , Brunet Theresa , Wagner Matias , Kasprian Gregor , Lehrner Johann , Zimprich Fritz , Bonelli Silvia B. , Krenn Martin
Published: April 2022

Objective:

Causative variants in SETD1B, encoding a lysine-specific methyltransferase, have recently been associated with a neurodevelopmental phenotype encompassing intellectual disability, autistic features, pronounced language delay, and epilepsy. It has been noted that long-term and deep phenotype data are needed to further delineate this rare condition.

Methods:

In this study, we provide an in-depth clinical characterization with long-term follow-up and trio exome sequencing findings to describe one additional individual affected by SETD1B-related disorder. The diagnostic workup was complemented by a functional magnetic resonance imaging (fMRI) study.

Results:

We report a 24-year-old male individual with an early-onset neurodevelopmental disorder with epilepsy due to the de novo missense variant c.5699A>G, p.(Tyr1900Cys) in SETD1B (NM_015048.1). He exhibited delayed speech development, autism spectrum disorder, and early-onset epilepsy with absence and generalized tonic-clonic seizures. Despite profoundly impaired communication skills, ongoing improvements regarding language production have been noted in adulthood. fMRI findings demonstrate abnormal language activation and resting-state connectivity structure.

Conclusion:

Our report expands the previously delineated phenotype of SETD1B-related disorder and provides novel insights into underlying disease mechanisms.
Rare Cutaneous Malignancies in Skin of Color
Authors: Mosallaei Daniel , Lee Erica B. , Lobl Marissa , Clarey Dillon , Wysong Ashley
Published: April 2022

BACKGROUND

There is a scarcity of information regarding the clinical characteristics of rare cutaneous malignancies in skin of color that has yet to be comprehensively explored.

OBJECTIVE

To review and compile the racial differences in epidemiology, clinical presentation, histology, treatments, and outcomes of 3 rare skin cancers: dermatofibrosarcoma protuberans (DFSP), Merkel cell carcinoma (MCC), and sebaceous carcinoma (SC).

METHODS

Several searches with keywords denoting specific skin cancer type and race were conducted on PubMed to complete this narrative review.

RESULTS

We analyzed 50 sources that were relevant to the initial objective.

CONCLUSION

The literature demonstrates that there are nuances in DFSP, MCC, and SC unique to African Americans, Asians/Pacific Islanders, and Hispanics that may differ significantly from Caucasian counterparts. African Americans consistently suffer from the worst clinical outcomes in all 3 rare cutaneous malignancies reviewed. Greater physician awareness and knowledge of the discussed racial differences is the preliminary step to address these disparities.
On the Use of Covariate Supersets for Identification Conditions
Authors: Zivich Paul N. , Shook-Sa Bonnie E. , Edwards Jessie K. , Westreich Daniel , Cole Stephen R.
Published: April 2022

The union of distinct covariate sets, or the superset, is often used in proofs for the identification or the statistical consistency of an estimator when multiple sources of bias are present. However, the use of a superset can obscure important nuances. Here, we provide two illustrative examples: one in the context of missing data on outcomes, and one in which the average causal effect is transported to another target population. As these examples demonstrate, the use of supersets may indicate a parameter is not identifiable when the parameter is indeed identified. Furthermore, a series of exchangeability conditions may lead to successively weaker conditions. Future work on approaches to address multiple biases can avoid these pitfalls by considering the more general case of nonoverlapping covariate sets.
Towards Precision Dosing of Clozapine in Schizophrenia: External Evaluation of Population Pharmacokinetic Models and Bayesian Forecasting
Authors: Lereclus Aurélie , Korchia Théo , Riff Camille , Dayan Frédéric , Blin Olivier , Benito Sylvain , Guilhaumou Romain
Published: April 2022

Background:

Therapeutic drug monitoring and treatment optimization of clozapine are recommended, owing to its narrow therapeutic range and pharmacokinetic (PK) variability. This study aims to assess the clinical applicability of published population PK models by testing their predictive performance in an external data set and to determine the effectiveness of Bayesian forecasting (BF) for clozapine treatment optimization.

Methods:

Available models of clozapine were identified, and their predictive performance was determined using an external data set (53 patients, 151 samples). The median prediction error (PE) and median absolute PE were used to assess bias and inaccuracy. The potential factors influencing model predictability were also investigated. The final concentration was reestimated for all patients using covariates or previously observed concentrations.

Results:

The 7 included models presented limited predictive performance. Only 1 model met the acceptability criteria (median PE ≤ ±20% and median absolute PE ≤30%). There was no difference between the data used for building the models (therapeutic drug monitoring or PK study) or the number of compartments in the models. A tendency for higher inaccuracy at low concentrations during treatment initiation was observed. Heterogeneities were observed in the predictive performances between the subpopulations, especially in terms of smoking status and sex. For the models included, BF significantly improved their predictive performance.

Conclusions:

Our study showed that upon external evaluation, clozapine models provide limited predictive performance, especially in subpopulations such as nonsmokers. From the perspective of model-informed prediction dosing, model predictability should be improved using updating or metamodeling methods. Moreover, BF substantially improved model predictability and could be used for clozapine treatment optimization.
Efficacy evaluation of Chinese herbal medicine, VGH-BPH1, for patients with benign prostatic hyperplasia: A randomized, double-blind, placebo-controlled, and crossover study
Authors: Tran Diem Ngoc Hong , Yeh Hsin-Fu , Huang William J. , Wu Pei-Wen , Liao Ying-Ju , Hwang Shinn-Jang , Kung Yen-Ying , Yang Jen-Lin , Wu Ta-Peng , Hsu Chung-Hua , Chen Fang-Pey
Published: April 2022

Background:

Benign prostatic hyperplasia (BPH) can affect quality of life and cause various complications. Previous studies have suggested that Chinese herbal medicine can alleviate symptoms in patients with BPH. This study aimed to investigate whether the Chinese herbal medicine prescription VGH-BPH1 can alleviate BPH symptoms when used as an add-on treatment.

Methods:

In this crossover, randomized, double-blind, placebo-controlled trial, patients with BPH were randomly segregated into two groups: group A received VGH-BPH1, and group B received a placebo for 8 weeks. Subsequently, after a 2-week wash-out period, the two groups were switched to the opposite treatment for another 8 weeks. The International Prostate Symptoms Score and Aging Male Symptoms Score were adopted as the primary outcomes to assess improvement in BPH and patient quality of life. The secondary outcomes were the International Index of Erectile Function, Constitution Chinese Medicine Questionnaire, uroflowmetry results, and postvoid residual urine volume.

Results:

VGH-BPH1 treatment significantly decreased the International Prostate Symptoms Score total score (p = 0.027); however, no significant difference was observed between the treatment and placebo groups. The Aging Male Symptoms Score “joint pain and muscular ache” score in the VGH-BPH1 group was significantly lower than that of the placebo group (p = 0.022). The “physical exhaustion” score also exhibited a decreasing trend when both groups were compared (p = 0.057).

Conclusion:

Although VGH-BPH1 treatment did not outperform the placebo in terms of improving BPH symptoms, it resulted in improvement in several quality of life indicators when relative to the placebo. Future research using a larger sample size with appropriate amendments to the protocol should be conducted to further investigate the effects of VGH-BPH1.