bluuebunny/crossref_metadata_2025 huggingface dataset:
Equivalent permittivity and design of nanoparticle lasers for nonlocal polar dielectrics
Authors: Yu Naifu , Gao Lei , Huang Yang
Published: May 2023

Polar dielectrics are being actively investigated as a promising platform for mid-infrared nanophotonics, and it indicates dramatic nonlocal phenomena at the nanoscale. Based on full-wave nonlocal extended Mie theory, we analytically derive the equivalent permittivity of nonlocal polar dielectric nanospheres. Then, we establish the conditions for surface phonon amplification by stimulated emission of radiation of the nonlocal polar dielectric core-gain shell nanoparticle laser based on phonon polaritons. The results show that the nonlocality dramatically affects the selection of the gain medium for lasing condition, which also indicates a new degree of freedom in the modulation of the gain medium. The validity of the derived equivalent permittivity is demonstrated by comparing the obtained extinction spectra and the choice of the threshold gain with those under nonlocal extended Mie theory. Our research may provide a practical tool for designing phonon polariton nanoparticle lasers.
Study on flow characteristics of leakage in the last stage inner blade tip clearance of steam turbine
Authors: Lv Zhijia , Liu Xiaolong , Jiang Zhicheng , Lin Zhao , Zhao Zicheng , Han Xu
Published: May 2023

Internal steam leakage in steam turbines from the high-pressure side to the low-pressure side through clearances causes loss, resulting in reduced efficiency and potentially compromising the safe operation of the turbine. Therefore, a comprehensive understanding of the flow characteristics of leakage through blade tip clearances is crucial to improve the efficiency of steam turbines. In this paper, the last stage blades of the low-pressure cylinder of a certain 600 MW ultra-supercritical steam turbine unit were studied. A wet steam flow model and a turbulence model were established, and the flow characteristics of the last stage under different inlet parameters, outlet parameters, and tip clearance sizes were analyzed. The results showed that an increase in the clearance size affects the inlet and outlet steam angles of the rotor blades, with significant changes occurring near the blade tip. The main flow velocity inside the rotor blade channel fluctuates violently starting from the 70% axial position. The high entropy region is located near the exit flow region of the rotor blade, with its range expanding as the clearance size increases. The entropy change is significant at 60% blade height and above, with more intense changes occurring in the blade tip area. The relative leakage amount and efficiency change uniformly with clearance variation. Generally, for every 0.1% increase in clearance height, the relative leakage amount increases by ∼0.31%–0.42%, and the stage efficiency decreases by 0.34%–0.44%. The results of this study can provide a theoretical basis and guidance for improving the flow efficiency of steam turbines.
Yerba mate (Ilex paraguariensis) agroforestry systems: intraspecific differences in water relations and hydraulic architecture
Authors: Villagra Mariana , di Francescantonio Débora , Munaretto Nestor , Campanello Paula I.
Published: May 2023

Intensive farming systems benefit from the additional ecosystem services provided by tree integration, which generate different growing conditions for the main crop. We studied yerba mate (Ilex paraguariensis) responses to growing conditions in monoculture (the conventional cropping system of yerba mate) and in three agroforestry systems: (1) yerba mate + Balfourodendron riedelianum; (2) yerba mate + Peltophorum dubium; and (3) yerba mate + Toona ciliata. Mainly, we focused on water relations and the hydraulic architecture of yerba mate. Agroforestry cropping systems provided a shade cover of around 34–45% and yielded as high as the conventional system. The shade cover influenced the allocation pattern to enhance leaf light capture, incrementing the leaf area to the sapwood area at the branch level. We also found a higher specific hydraulic conductivity in stems of yerba mate plants in consortium with T. ciliata than in the conventional cropping system, as well as higher resistance to water deficits due to lower vulnerability to embolism in the stems. During a severe drought, yerba mate plants had a similar stem and leaf water potential in both agricultural systems. Still, plants in monoculture had lower hydraulic safety margins and higher signs of leaf damage and mortality. This indicates that integrating trees into the yerba mate cultivation increases water stress resistance which would be beneficial to avoid restrictions on crop productivity under severe droughts induced by climate change.
Stars and junction conditions in Einstein–Gauss–Bonnet gravity
Authors: Brassel Byron P , Maharaj Sunil D , Goswami Rituparno
Published: May 2023

The junction conditions for a higher dimensional spherically symmetric charged and anisotropic static star are derived in Einstein–Gauss–Bonnet (EGB) gravity with nonvanishing cosmological constant. It is shown that for a timelike boundary hypersurface of zero thickness, the generalised matching conditions across this surface in EGB gravity are satisfied. A sufficient condition is that the Israel-Darmois conditions are valid. Therefore it is possible to generate a complete stellar model in EGB gravity. The interior matches to the exterior higher dimensional charged Boulware–Deser spacetime with cosmological constant. The barotropic radial pressure has to vanish at the boundary of the star which is also the case in general relativity.
Raman scattering studies of Si/B4C periodic multilayer mirrors with an operating wavelength of 13.5 nm
Authors: Kumar Niranjan , Smertin Ruslan M , Prathibha B S , Nezhdanov Aleksey V , Drozdov Mikhail N , Polkovnikov Vladimir N , Chkhalo Nikolay I
Published: May 2023

In order to obtain mirrors with a minimum value of residual stress, periodic multilayer mirrors composed of Si/B4C were deposited by magnetron sputtering with change in pressure of sputtering Ar gas. The microstructure and phase of Si and B4C was manipulated by the pressure of Ar gas which overall affected the stress in the mirrors. The minimum stress was obtained at higher pressure of sputter Ar gas, which showed the formation of amorphous boron, amorphous B4C, free carbon atoms and amorphous carbon structure in the B4C layers, investigated by Raman scattering spectroscopy. In Raman spectroscopy, a transverse optical (TO) mode of amorphous Si was shifted to lower frequency with increase in Ar gas pressure, which indicated relaxation of stress, also confirmed by the curvature measurement of mirrors. However, in the case of high residual stress, the amorphous B4C was a prominent phase in this layer and the frequency of the TO mode of amorphous Si was blue-shifted. Microstructure and stress affected the interfaces and modulation of the periodicity of the Si/B4C mirrors, investigated by secondary ion mass spectroscopy, which influenced the reflectivity of the mirrors.
Evaluation of material surface properties using one-way collinear mixing Rayleigh waves
Authors: Lu Lu , Xu Caibin , Lai Quanqing , Deng Mingxi
Published: May 2023

Nonlinear Rayleigh waves are useful for material surface damage detection. Traditional non-destructive testing (NDT) techniques based on higher harmonics of Rayleigh waves are inevitably interfered with by the nonlinearity of measurement systems. To overcome this disadvantage, an approach based on one-way collinear mixing Rayleigh waves (MRWs) is proposed to evaluate the material surface properties. A wedge with two different incidence angles for the excitations of transverse and longitudinal waves is designed to generate one-way collinear MRWs. The one-way collinear MRWs can be generated on the whole surface of the material, and propagate along the propagation way under one excitation. Numerical simulations of one-way collinear MRWs under different surface properties, which are characterized using different third-order elastic constants, are studied on a semi-infinite aluminum. Experiments are also conducted on the aluminum specimen, whose surface is corroded by hydrochloric acid so as to change the material surface properties. Both numerical and experimental results show that the one-way collinear MRWs are generated effectively, and the defined relative acoustic nonlinearity parameter increases with the propagation distance as well as the severity of the material surface damages. The results verify the effectiveness of the proposed MRW-based method and prove that it would be a promising NDT technique for the accurate evaluation of material surface properties.
A robust and efficient model for transmission of surface plasmon polaritons onto metal–insulator–metal apertures
Authors: Barış İplikçioğlu S , Aksun M I
Published: May 2023

A simple yet accurate model for the transmission of surface plasmon polaritons (SPPs) in a finite metal–insulator–metal (MIM) waveguide to the sides of the apertures is proposed and demonstrated to be more accurate than the available models. It is as simple as using a magnetic current density across the plane of the aperture whose value is defined by the SPPs with any number of modes in the waveguide through the equivalence principle. Then, the generated SPPs on both sides of the aperture are extracted from the convolution integral of the equivalent current density and Green’s function. As a result, the model provides the transmission coefficients of the SPPs in the MIM waveguide to the side walls of the aperture accurately and efficiently; not only for symmetric MIM waveguides with a single isolating layer but also non-symmetric ones with multi-layered insulating materials. The results are in very good agreement with those obtained by the finite-difference time-domain method and better than the other approximations available in literature for a wide range of aperture widths.
Generic role of the Dzyaloshinskii–Moriya interaction in nanocrystalline ferromagnets
Authors: Erokhin Sergey , Berkov Dmitry , Michels Andreas
Published: May 2023

Motivated by recent experimental polarized neutron results, we present a numerical micromagnetic study of the interfacial (intergrain) Dzyaloshinskii–Moriya interaction (DMI) in nanocrystalline terbium. We demonstrate that the DMI-induced spin misalignment between adjacent nanograins is the reason for the formation of the asymmetric positive-negative pattern seen in polarized neutron scattering experiments. Analysis of the remagnetization process suggests the generic impact of the DMI on the macroscopic magnetic parameters of polycrystalline defect-rich materials.
Deep Learning Applications Based on WISE Infrared Data: Classification of Stars, Galaxies and Quasars
Authors: Zhao Guiyu , Qiu Bo , Luo A-Li , Guo Xiaoyu , Yao Lin , Wang Kun , Liu Yuanbo
Published: May 2023

The Wide-field Infrared Survey Explorer (WISE) has detected hundreds of millions of sources over the entire sky. However, classifying them reliably is a great challenge due to degeneracies in WISE multicolor space and low detection levels in its two longest-wavelength bandpasses. In this paper, the deep learning classification network, IICnet (Infrared Image Classification network), is designed to classify sources from WISE images to achieve a more accurate classification goal. IICnet shows good ability on the feature extraction of the WISE sources. Experiments demonstrate that the classification results of IICnet are superior to some other methods; it has obtained 96.2% accuracy for galaxies, 97.9% accuracy for quasars, and 96.4% accuracy for stars, and the Area Under Curve of the IICnet classifier can reach more than 99%. In addition, the superiority of IICnet in processing infrared images has been demonstrated in the comparisons with VGG16, GoogleNet, ResNet34, MobileNet, EfficientNetV2, and RepVGG-fewer parameters and faster inference. The above proves that IICnet is an effective method to classify infrared sources.
Theoretical Analysis of Random Scattering Induced by Microlensing
Authors: Zheng Wenwen , Chen Hou-Zun , Chen Xuechun , Li Guoliang
Published: May 2023

Theoretical investigations into the deflection angle caused by microlenses offer a direct path to uncovering principles of the cosmological microlensing effect. This work specifically concentrates on the the probability density function (PDF) of the light deflection angle induced by microlenses. We have made several significant improvements to the widely used formula from Katz et al. First, we update the coefficient from 3.05 to 1.454, resulting in a better fit between the theoretical PDF and our simulation results. Second, we developed an elegant fitting formula for the PDF that can replace its integral representation within a certain accuracy, which is numerically divergent unless arbitrary upper limits are chosen. Third, to facilitate further theoretical work in this area, we have identified a more suitable Gaussian approximation for the fitting formula.
N ≥ 2 particles in the framework of TeVeS
Authors: Horwitz L.P.
Published: May 2023

About 40 years ago, since no viable candidate for “dark matter” was discovered, M. Milgrom and J.Bekenstein introduced a non-covariant modification of gravitational theory (MOND) to account for the anomalous rotation curves of galaxies. Bekenstein and Sanders then developed a relativistically covariant form of the theory, called TeVeS, involving scalar and tensor fields, which accounts well for the rotation curves as well for the observed lensing of background radiation around galaxies without the introduction of “dark matter”. The dynamical behavior of a particle in such a gravitational theory has been recently discussed by Horwitz, Gershon and Schiffer. In this paper we study the dynamics of the N ≥ 2 particle problem in the framework of the TeVeS theory.
Parametrized Relativistic Quantum Theory in Curved Spacetime
Authors: Fanchi John R.
Published: May 2023

The purpose of this paper is to present a parametrized relativistic quantum theory (pRQT) in curved spacetime. The formulation of pRQT in curved spacetime is developed and applied to free particle motion in flat and curved spacetime. It provides a theory for calculating probability amplitudes in curved spacetime. Unlike other formulations of parametrized relativistic dynamics (pRD), this work assumes that the metric tensor does not depend on the invariant evolution parameter.
A vielbein formalism for SHP general relativity
Authors: Land Martin
Published: May 2023

The 4+1 formalism in general relativity expresses the Einstein equations as a manifestly covariant initial value problem, resulting in a pair of first order evolution equations for the metric γμv
and intrinsic curvature Kμv
of spacetime geometry (μ, v = 0, 1, 2, 3). This approach extends the Stueckelberg-Horwitz-Piron (SHP) framework, a covariant approach to canonical particle mechanics and field theory employing a Lorentz scalar Hamiltonian K and an external chronological parameter τ. The SHP Hamiltonian generates τ-evolution of spacetime events xμ
(τ) or ψ (x, τ) in an a priori unconstrained phase space; standard relativistic dynamics can be recovered a posteriori by imposing symmetries that express the usual mass shell constraint for individual particles and fields as conservation laws. As a guide to posing field equations for the evolving metric, we generalize the structure of SHP electrodynamics, with particular attention to O(3,1) covariance. Thus, the 4+1 method first defines a 5D pseudo-spacetime as a direct product of spacetime geometry and chronological evolution, poses 5D field equations whose symmetry must be broken to 4D, and then implements the implied 4+1 foliation to obtain evolution equations. In this paper, we sharpen and clarify the interpretation of this decomposition by introducing a fixed orthonormal quintrad frame and a 5D vielbein field that by construction respects the preferred 4+1 foliation. We show that for any diagonal metric, this procedure enables the evolution equation for the metric to be replaced by an evolution equation for the vielbein field itself, simplifying calculation of the spin connection and curvature.
Mechanics of Spacetime with Surface Tension and Preferred Curvature
Authors: Perko H A
Published: May 2023

In previous publications, it was argued that because energy and matter are aligned in the thin increment of present time for an observer, spacetime should and must have surface tension. In this paper, we review how to apply 4-dimensional continuum mechanics with imaginary time coordinates to derive a mechanical model of spacetime with surface tension. Then, to continue model development, we discuss the concept of preferred curvature from the physical chemistry of surfaces and attempt to apply those concepts to spacetime geometry. We show how the model exhibits quantum fluctuations at the Plank scale and components resembling dark matter and dark energy at the cosmic scale.
Time measurement with accelerating light-clocks
Authors: Ben-Ya’acov Uri
Published: May 2023

The clock hypothesis in relativity states that the rate of time as measured by any clock is determined by its Minkowskian proper-time, regardless of the nature of its motion; in particular independent of its acceleration, depending only on its instantaneous velocity. However, a unique proper-time may be assigned to an accelerating clock, as to any physical system, only in the limit of being point-like. But clocks, by their very nature, must be spatially extended systems, to allow an internal periodical mechanism. Therefore the question, How does the internal structure of the clock affect the clock hypothesis?

The simplest model to examine the clock hypothesis is the so-called ‘light clock’, consisting of two mirrors with a light signal reflected between them. So far, such examinations were carried out mainly in the limits of point-like clocks and/or constant acceleration. Here the clock hypothesis is theoretically examined for spatially extended linearly accelerated light-clocks, parallel and vertical relative to the direction of motion, with arbitrarily varying accelerations. Using the rapidity of the clock as its evolution parameter, a Lorentz covariant analysis is neatly performed. Taking into account the spatial extension of the clock, differences between externally measured Minkowskian proper-times and the time-scale determined by the internal periodical mechanism of the clock are computed.

Although these differences are practically very minute – of order aL/c
2 for characteristic acceleration a and spatial dimension L of the clock – theoretically they cannot be ignored. They indicate inherent inconsistency between the externally measured proper-time – the physical time-line which consists of moments-of-time – and the intrinsically defined age – the internal time-line, consisting of durations, intervals-of-time.
The Proton and Occam’s Razor
Authors: Vassallo Giorgio , Kovacs Andras
Published: May 2023

Otto Stern’s 1933 measurement of the unexpectedly large proton magnetic moment indicated to most physicists that the proton is not a point particle. At that time, many physicists modeled elementary particles as point particles, and therefore Stern’s discovery initiated the speculation that the proton might be a composite particle. In this work, we show that despite being an elementary particle, the proton is an extended particle. Our work is motivated by the experimental data, which we review in section 1.

By applying Occam’s Razor principle, we identify a simple proton structure that explains the origin of its principal parameters. Our model uses only relativistic and electromagnetic concepts, highlighting the primary role of the electromagnetic potentials and of the magnetic flux quantum ΦM=h/e. Unlike prior proton models, our methodology does not violate Maxwell’s equation, Noether’s theorem, or the Pauli exclusion principle.

Considering that the proton has an anapole (toroidal) magnetic moment, we propose that the proton is a spherical shaped charge that moves at the speed of light along a path that encloses a toroidal volume. A magnetic flux quantum ΦM=h/estabilizes the proton’s charge trajectory. The two curvatures of the toroidal and poloidal current loops are determined by the magnetic forces associated with ΦM. We compare our calculations against experimental data.
Experimental analysis of energy production of a hybrid thermal-photovoltaic solar panel enhanced with phase-change material
Authors: Listarhov (Lixandru) A , Catalina T
Published: May 2023

The paper presents the difference between 2 photovoltaic thermal panels (PV/T), panels with the same initial characteristics. During the experiment, in PV/T panel no. 1 we introduce 14 kg of RT 35 phase change material, material with a liquid density at 45°C of 0.77 kg/l. According to the technical sheet of the panel, PV/T volume no. 1 was occupied 50% with PCM RT 35. Panel no. 2 is a normal PV/T. Following measurements made with the data recorder BTM-4208 SD, a difference of 6°C results on the faces of the panels. The energy production for PV/T no. 1 with PCM RT35 is 10.046 kWh compared to PV/T panel no. 2 where the energy production is 8.443 kWh. Conclusion: the efficiency of the PV/T panel no. 1 with PCM RT 35 is better by 15.20% compared to panel no. 2 PV/T.
Establishing the energy content of natural gas residential consumption : example with Belgian field-test applications
Authors: Paulus N , Lemort V
Published: May 2023

In the context of the much-needed energy transition, monitoring of residential energy appliances is more and more common in order to evaluate (and improve) their field-test performance in real applications. Many residential heating appliances use natural gas as energy source : residential gas boilers, gas engine heat pumps, gas absorption heat pumps; fuel cell-based cogeneration units, internal combustion engine cogeneration units, etc. Unfortunately, for simplicity and costs reasons, only the volume of the consumed natural is measured at the inlet of the monitored residential heating appliance. This volume, and the equivalent energy level that it contains and that is required for efficiency calculations, is affected by the atmospheric pressure and the temperature at the field-test site, as well as by the always varying natural gas composition. This paper demonstrates the method that has been used in Belgian field-test studies conducted on residential heating appliances to establish the energy content of the consumed natural gas.
Simplified test bench for experimental investigations of space heating appliances
Authors: Paulus N , Lemort V
Published: May 2023

The energy transition requires efficient space heating appliances. In that context, it is common that thermodynamics laboratories are asked to conduct experimental investigations on those appliances to establish or verify their performance. This paper aims to offer and report an example of a very simple test rig that allows for controlling both the space heating water flow rate and the space heating return temperature. Space heating depart temperature thus depends on those two controlled parameters as well as the heat transfer rate provided by the space heating appliance, based on its settings. The test rig described in this paper has been used to conduct experimental studies on residential Solid Oxide Fuel Cells used as micro-cogeneration units. It has the advantage of being reproductible or reused with other residential space heating appliances. It can easily be adapted for refrigeration appliances testing or even heat exchanger characterization Also, the test rig controlling the space heating flow rate and working temperature implies an approximative cost of only about 1 k€ (with 2021 hardware prices, without the space heating appliance to be tested).
Climate variability in the extra-Carpathian area of Romania in the context of climate change
Authors: Radu Maria-Alexandra , Bandoc Georgeta
Published: May 2023

The aim of this paper is to analyze in 2012-2017 the evolution of climate trends and meteorological parameters with significant relevance in agriculture, from the perspective of the potential risk associated with climate change and the need to adapt to their effects. Agrometeorological monitoring of a crop area includes information on the assessment of biological conditions for plant growth and development, the duration of the growing season and the vulnerability of agricultural areas to water and heat stress, in order for beneficiaries to choose the most effective measures. to prevent and reduce the negative effects on crops. In order to identify some peculiarities, we analyzed the average monthly values of temperature and atmospheric precipitation at the 63 meteorological stations with agrometeorological program, in the extra-Carpathian area of Romania, from 2012-2017 and were compared with the data from the reference period 1981-2010. Also, the temperature and precipitation data were spatialized with the highlighting of the changes in the study area compared to the reference period. Based on the calculation and analysis of agrometeorological parameters of thermal and water stress, this paper presents the importance of knowing the evolution of meteorological conditions with significant impact on the agricultural sector.
Analysis on IMF Loan Conditions with more Detrimental Impact on the Economy: A Case Study of Nigeria
Authors: Shafiu R. M. , Salleh M. A. , Bala H. , Shafiu A. M. , Abdullahi Umar
Published: May 2023

Past studies have shown that nations that borrow money from the International Monetary Fund (IMF) have greater rates of poverty, unemployment, and inflation than countries that do not borrow from the IMF. This is despite the fact that the IMF claims that fostering economic development is one of its objectives. The IMF loans conditions that are shown to have the most detrimental impact on economies are the subject of this study, which focused, specifically on Nigeria. In order to obtain data for this research, primary data sources such as official documents, newspapers, journals, and other similar sources were utilized, and Neoliberal theory was employed as the theoretical foundation for the study. Our research showed that the IMF loan conditions of currency devaluation and subsidy removal negatively impacted not just Nigeria’s economy but also the nation’s overall standard of living. As a result, it was recommended that the government should make an effort to diversify the economy, modify its relations with international financial organizations like the IMF and the World Bank, and give the populace access to the necessary resources to improve their standard of living.
The necessity of resilience: Bucharest vulnerability in seismic context
Authors: Păunescu M , Stănescu A A , Luca O
Published: May 2023

This paper aims to perform an overview of the general situation related to Bucharest vulnerability in seismic context. Brief literature review on the subject is performed, together with emphasizing success factors for improving resilience in other countries. The paper is presenting the situation related to seismic resilience in Bucharest, proposing short- and long-term measures and introduction of CRO concept in the local administration.
Synthesis and anisotropic magnetic properties of LiCrTe
2
single crystals with a triangular-lattice antiferromagnetic structure
Authors: Witteveen Catherine , Nocerino Elisabetta , López-Paz Sara A , Jeschke Harald O , Pomjakushin Vladimir Y , Månsson Martin , von Rohr Fabian O
Published: May 2023

We report on the synthesis of LiCrTe

2

single crystals and on their anisotropic magnetic properties. We have obtained these single crystals by employing a Te/Li-flux synthesis method. We find LiCrTe

2

to crystallize in a TlCdS

2

-type structure with cell parameters of a = 3.9512(5) Å and c = 6.6196(7) Å at T = 175 K. The content of lithium in these crystals was determined to be neary stoichiometric by means of neutron diffraction. We find a pronounced magnetic transition at

T

N

a
b

= 144 K and

T

N

c

= 148 K, respectively. These transition temperatures are substantially higher than earlier reports on polycrystalline samples. We have performed neutron powder diffraction measurements that reveal that the long-range low-temperature magnetic structure of single crystalline LiCrTe

2

is an A-type antiferromagnetic structure. Our DFT calculations are in good agreement with these experimental observations. We find the system to be easy axis with moments oriented along the c-direction experimentally as well as in our calculations. Thereby, the magnetic Hamiltonian can be written as

H
=

H

H
e
i
s
e
n
b
e
r
g

+

∑
i

K
c

(

S
i
z

)
2

with

K
c

=
−
0.34

K (where

|

S
z

|

=

3
2

). We find LiCrTe

2

to be highly anisotropic, with a pronounced metamagnetic transition for

H
⊥
a
b

with a critical field of

μ

H

M
M

(5 K) ≈ 2.5 T. Using detailed orientation-dependent magnetization measurements, we have determined the magnetic phase diagram of this material. Our findings suggest that LiCrTe

2

is a promising material for exploring the interplay between crystal structure and magnetism, and could have potential applications in spin-based 2D devices.
Finite element de Rham and Stokes complexes in three dimensions
Authors: Chen Long , Huang Xuehai
Published: May 2023

Finite element de Rham complexes and finite element Stokes complexes with varying degrees of smoothness in three dimensions are systematically constructed in this paper. Smooth scalar finite elements in three dimensions are derived through a non-overlapping decomposition of the simplicial lattice.

H
(
div
)

H(\operatorname {div})

-conforming finite elements and

H
(
curl
)

H(\operatorname {curl})

-conforming finite elements with varying degrees of smoothness are devised based on these smooth scalar finite elements. The finite element de Rham complexes with corresponding smoothness and commutative diagrams are induced by these elements. The div stability of the

H
(
div
)

H(\operatorname {div})

-conforming finite elements is established, and the exactness of these finite element complexes is proven.
Modular curves with infinitely many quartic points
Authors: Hwang WonTae , Jeon Daeyeol
Published: May 2023

In this work, we determine all modular curves

X
0

(
N
)

X_0(N)

which admit infinitely many quartic points.
A universal bound in the dimensional Brunn-Minkowski inequality for log-concave measures
Authors: Livshyts Galyna
Published: May 2023

We show that for any even log-concave probability measure

μ
\mu

on

R

n

\mathbb {R}^n

, any pair of symmetric convex sets

K
K

and

L
L

, and any

λ
∈
[
0
,
1
]

\lambda \in [0,1]

,
<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" alttext="mu left-parenthesis left-parenthesis 1 minus lamda right-parenthesis upper K plus lamda upper L right-parenthesis Superscript c Super Subscript n Superscript Baseline greater-than-or-equal-to left-parenthesis 1 minus lamda right-parenthesis mu left-parenthesis upper K right-parenthesis Superscript c Super Subscript n Superscript Baseline plus lamda mu left-parenthesis upper L right-parenthesis Superscript c Super Subscript n Superscript Baseline comma">

μ
(
(
1
−
λ
)
K
+
λ
L

)

c
n

≥
(
1
−
λ
)
μ
(
K

)

c
n

+
λ
μ
(
L

)

c
n

,

\begin{equation*} \mu ((1-\lambda ) K+\lambda L)^{c_n}\geq (1-\lambda ) \mu (K)^{c_n}+\lambda \mu (L)^{c_n}, \end{equation*}

where

c
n

≥

n

−
4
−
o
(
1
)

c_n\geq n^{-4-o(1)}

. This constitutes progress towards the dimensional Brunn-Minkowski conjecture (see Richard J. Gardner and Artem Zvavitch [Tran. Amer. Math. Soc. 362 (2010), pp. 5333–5353]; Andrea Colesanti, Galyna V. Livshyts, Arnaud Marsiglietti [J. Funct. Anal. 273 (2017), pp. 1120–1139]). Moreover, our bound improves for various special classes of log-concave measures.
The 𝑄-shaped derived category of a ring — compact and perfect objects
Authors: Holm Henrik , Jørgensen Peter
Published: May 2023

A chain complex can be viewed as a representation of a certain self-injective quiver with relations,

Q
Q

. To define

Q
Q

, include a vertex

q
n

q_n

and an arrow

q
n

→

∂

q

n
−
1

q_n \xrightarrow {\partial } q_{n-1}

for each integer

n
n

. The relations are

∂
2

=
0

\partial ^2 = 0

.

Replacing

Q
Q

by a general self-injective quiver with relations, it turns out that some of the key properties of chain complexes generalise. Indeed, consider the representations of such a

Q
Q

with values in

A

Mod

{}_{A}\mspace {-1mu}\operatorname {Mod}

where

A
A

is a ring. We showed in earlier work that these representations form the objects of the

Q
Q

-shaped derived category,

D

Q

(
A
)

\mathcal {D}_{Q}(A)

, which is triangulated and generalises the classic derived category

D

(
A
)

\mathcal {D}_{}(A)

. This follows ideas of Iyama and Minamoto.

While

D

Q

(
A
)

\mathcal {D}_{Q}(A)

has many good properties, it can also diverge dramatically from

D

(
A
)

\mathcal {D}_{}(A)

. For instance, let

Q
Q

be the quiver with one vertex

q
q

, one loop

∂
\partial

, and the relation

∂
2

=
0

\partial ^2 = 0

. By analogy with perfect complexes in the classic derived category, one may expect that a representation with a finitely generated free module placed at

q
q

is a compact object of

D

Q

(
A
)

\mathcal {D}_{Q}(A)

, but we will show that this is, in general, false.

The purpose of this paper, then, is to compare and contrast

D

Q

(
A
)

\mathcal {D}_{Q}(A)

and

D

(
A
)

\mathcal {D}_{}(A)

by investigating several key classes of objects: Perfect and strictly perfect, compact, fibrant, and cofibrant.
Demanding Recognition: a New Framework for the Study of Political Clientelism
Authors: Klaus Kathleen , Paller Jeffrey W , Wilfahrt Martha
Published: May 2023

Despite increasingly programmatic politics and competitive elections, political clientelism remains an enduring feature of African politics. More so, while politicians rarely deliver on political promises, citizens continue to demand and participate in patron–client relations. While moral economy and instrumentalist accounts offer insight into the puzzling persistence of political clientelism, we offer an additional framework based on demands for social recognition. Beyond expectations of materialist exchange or the performance of cultural norms, citizens expect their political leaders to recognize them as dignified human beings and members of an identity group. Drawing on evidence from three diverse African contexts—urban Ghana, rural Senegal, and coastal Kenya—we argue that citizens engage in political clientelism as a vehicle for demanding three dimensions of social recognition: (i) To be seen and heard by leaders, (ii) to be respected as agents in the political process, and (iii) to be politically included and protected from harm. By providing new insights into the enduring logics of clientelism, citizen strategies amidst unequal power relationships, and the role of emotions in democratic politics, we aim to reconcile existing approaches and bring them into a more unified framework.
Affective Disturbance and Neurocognitive Variability in College Athletes
Authors: Thomas Garrett A , Bradson Megan L , Riegler Kaitlin E , Arnett Peter A
Published: May 2023

Objective

Research on the neurocognitive effects of comorbid mood/anxiety disturbance in college athletes is limited. Previous research found that athletes with comorbid depression/anxiety performed worse on measures of attention/processing speed (A/PS) at baseline compared to healthy controls. However, this work solely examined mean performance. The current study expands upon this work by examining intraindividual variability (IIV) in relation to affective disturbance.

Method

835 (M = 624, F = 211) collegiate athletes completed baseline neuropsychological testing. Athletes were separated into four groups (Healthy Mood [n = 582], Depression Alone [n = 137], Anxiety Alone [n = 54], and Co-Occurring Depression/Anxiety [n = 62]) based on self-reported anxiety and depression. IIV was examined globally and within composites of A/PS and memory via intraindividual standard deviation, with higher scores indicating greater variability.

Results

Linear regression results revealed that the Co-Occurring Depression/Anxiety group exhibited greater variability within the memory composite compared to the Healthy Mood group, as well as the Depression Alone and Anxiety Alone groups. The Depression Alone and Anxiety Alone groups did not differ from the Healthy Mood group on memory IIV. None of the groups differed on A/PS or global IIV.

Conclusions

Athletes with co-occurring depression/anxiety demonstrated greater variability in performance on memory tasks. Greater dispersion is predictive of greater cognitive decline following concussion; therefore, it is important that neuropsychological performance is interpreted beyond measures of central tendency. These findings also highlight the importance of having baseline data available for athletes with affective disturbance, as these factors may influence performance, place athlete at risk for poorer outcomes, and skew future post-concussion comparisons.
The Efficacy of Injection Penile Girth Enhancement as an Option for Small Penis Syndrome Management
Authors: Boiko Mykola I , Notsek Mykola S , Boiko Oleksandr M
Published: May 2023

Background

In recent years aesthetic injection techniques with soft tissue fillers have become popular worldwide due to their effectiveness, safety, and low cost. There is no standard approach to the management and follow-up of patients seeking penile enlargement procedures described in the literature, and the surgical penile enlargement methods are controversial.

Objectives

The goals of this study were to assess the effect of injection penile girth enlargement on sexual relationship satisfaction, confidence, and self-esteem, and to evaluate the clinical efficacy and safety of this procedure for the management of men with small penis syndrome (SPS).

Methods

This was a single-center, clinical case series study executed from January 2019 to February 2021, which involved 148 men who were unsatisfied with the shape of their normal-size penises and requested penis girth correction.

Results

A total of 132 patients completed full treatment and follow-up. Mean girth enlargement was 1.7 ± 0.32 cm for the midshaft and 1.5 ± 0.32 cm for the glans of the penis. Satisfaction with sexual life improved. Mean scores increased by 17.9 ± 3.04 points for sexual relationship satisfaction and by 12.2 ± 3.17 points for confidence. The mean score for self-esteem increased by 8 ± 2.8 and by 4.3 ± 0.97 points for overall relationship satisfaction.

Conclusions

Penile enlargement with hyaluronic acid injection positively affects sexual relationship satisfaction, confidence, and self-esteem of men with SPS. The rate of psychosocial improvement does not correlate with penile size changes. It is a simple, safe, and effective technique that can be used in daily clinical practice.

Level of Evidence: 4
fimpera: drastic improvement of Approximate Membership Query data-structures with counts
Authors: Robidou Lucas , Peterlongo Pierre
Published: May 2023

Motivation

High throughput sequencing technologies generate massive amounts of biological sequence datasets as costs fall. One of the current algorithmic challenges for exploiting these data on a global scale consists in providing efficient query engines on these petabyte-scale datasets. Most methods indexing those datasets rely on indexing words of fixed length k, called k-mers. Many applications, such as metagenomics, require the abundance of indexed k-mers as well as their simple presence or absence, but no method scales up to petabyte-scaled datasets. This deficiency is primarily because storing abundance requires explicit storage of the k-mers in order to associate them with their counts. Using counting Approximate Membership Queries (cAMQ) data structures, such as counting Bloom filters, provides a way to index large amounts of k-mers with their abundance, but at the expense of a sensible false positive rate.

Results

We propose a novel algorithm, called fimpera, that enables the improvement of any cAMQ performance. Applied to counting Bloom filters, our proposed algorithm reduces the false positive rate by two orders of magnitude and it improves the precision of the reported abundances. Alternatively, fimpera allows for the reduction of the size of a counting Bloom filter by two orders of magnitude while maintaining the same precision. fimpera does not introduce any memory overhead and may even reduces the query time.

Availability and implementation

https://github.com/lrobidou/fimpera.
Surgical treatment of hilar cholangiocarcinoma: retrospective analysis
Authors: Li Bin , Li Zhishuai , Qiu Zhiquan , Qin Yingyi , Gao Qingxiang , Ao Jianyang , Ma Wencong , Jiang Xiaoqing
Published: May 2023

Background

Achieving a better prognosis for patients and reducing the risk of complications are primary considerations in surgical decisions for hilar cholangiocarcinoma.

Methods

A retrospective analysis of the authors' clinical practice outcomes in the surgical management of patients with hilar cholangiocarcinoma following the planned-hepatectomy surgical treatment programme between 2009 and 2018.

Results

Some 473 patients were included, of whom 127 (26.8 per cent) underwent bile duct tumour resection alone, 44 (9.3 per cent) underwent bile duct tumour resection combined with restrictive hepatectomy, and 302 (63.8 per cent) underwent bile duct tumour resection combined with extensive hepatectomy. R0 resection was achieved in 82.2 per cent and the postoperative complication rate was similar between the different operations. The 5-year survival rates after surgery were 37.0, 37.3, and 28.4 per cent in the bile duct tumour resection alone, restrictive hepatectomy, and extensive hepatectomy groups respectively, with no statistically significant differences. As TNM staging progressed, the 1–5-year cumulative survival rate for the patients in the three groups showed a significant downward trend.

Conclusion

In the setting of a high-volume centre, a planned-hepatectomy surgical treatment programme helps to strike a better balance between achieving radical tumour resection for hilar cholangiocarcinoma and reasonable control of the extent of surgical damage.
Workarounds: The Risks and the Rewards
Authors: White Martin
Published: May 2023

Your most innovative employees may be creating shadow IT solutions to the business problems they face. Martin White, Principal Analyst at SearchResearch Online, takes a tour of these workarounds and considers what they mean for IT leaders.
Futurology
Authors: Lucas Matt
Published: May 2023

Matt Lucas FBCS explores the forces driving advancements in digital health.
Mentoring
Authors: Yetim Adem
Published: May 2023

Adem Yetim IntPE FIET FBCS discusses cybersecurity and mentoring in digital transformation.
Time-varying effects are common in genetic control of gestational duration
Authors: Juodakis Julius , Ytterberg Karin , Flatley Christopher , Sole-Navais Pol , Jacobsson Bo
Published: May 2023

Preterm birth is a major burden to neonatal health worldwide, determined in part by genetics. Recently, studies discovered several genes associated with this trait or its continuous equivalent—gestational duration. However, their effect timing, and thus clinical importance, is still unclear. Here, we use genotyping data of 31 000 births from the Norwegian Mother, Father and Child cohort (MoBa) to investigate different models of the genetic pregnancy ‘clock’. We conduct genome-wide association studies using gestational duration or preterm birth, replicating known maternal associations and finding one new fetal variant. We illustrate how the interpretation of these results is complicated by the loss of power when dichotomizing. Using flexible survival models, we resolve this complexity and find that many of the known loci have time-varying effects, often stronger early in pregnancy. The overall polygenic control of birth timing appears to be shared in the term and preterm, but not very preterm, periods and exploratory results suggest involvement of the major histocompatibility complex genes in the latter. These findings show that the known gestational duration loci are clinically relevant and should help design further experimental studies.
On the Notion of Metaplectic Barbasch–Vogan Duality
Authors: Barbasch Dan , Ma Jia-Jun , Sun Binyong , Zhu Chen-Bo
Published: May 2023

In analogy with the Barbasch–Vogan duality for real reductive linear groups, we introduce a duality notion useful for the representation theory of the real metaplectic groups. This is a map on the set of nilpotent orbits in a complex symplectic Lie algebra, whose range consists of the so-called metaplectic special nilpotent orbits. We relate this duality notion with the theory of primitive ideals and extend the notion of special unipotent representations to the real metaplectic groups. We also interpret the duality map in terms of double cells of Weyl group representations.
Sexually Transmitted Infections and Risk of Epithelial Ovarian Cancer: Results From the Finnish Maternity Cohort
Authors: Skarga Elizaveta , Surcel Heljä-Marja , Kaaks Rudolf , Waterboer Tim , Fortner Renée T
Published: May 2023

Background

Sexually transmitted infections, specifically Chlamydia trachomatis (CT), may be associated with epithelial ovarian cancer (EOC) risk. The association between CT and EOC subtypes is unclear. Our aim was to investigate whether history of CT and other infections (Mycoplasma genitalium [MG], herpes simplex virus type 2 [HSV-2], and human papillomavirus [HPV]) are associated with EOC risk by histotype.

Methods

We measured antibodies (Abs) to CT, MG, HSV-2, and HPV-16/18 in serum samples in a nested case-control study in the Finnish Maternity Cohort (N = 484 cases 1:1 matched to controls). Logistic regression was used to calculate relative risks (RRs) and 95% confidence intervals (CIs) in seropositive versus seronegative individuals in all cases, as well as serous (n = 249), clear cell and endometrioid (n = 91), and mucinous (n = 144) EOC.

Results

CT seropositivity was not associated with EOC risk (eg, CT pGP3-Ab: RR, 0.92 [95% CI, .72–1.19]), regardless of disease subtype. We observed a positive association between MG seropositivity and mucinous EOC (RR, 1.66 [95% CI, 1.09–2.54]; P for heterogeneity by histotype ≤ .001), but not other subtypes. No associations were observed with seropositivity to multiple STIs.

Conclusions

CT infection was not associated with EOC risk, with associations observed only for MG and mucinous EOC. Mechanisms linking MG to mucinous EOC remain to be elucidated.
Security Attacks and Share Valuations
Authors: Ford Adrian
Published: May 2023

Dr Adrian Ford MBCS explores how markets react to information security incident announcements about publicly listed companies. Three types of events are investigated: data breaches, GDPR infringement fines and CISO appointments.