bluuebunny/crossref_metadata_2025 huggingface dataset:
Gravitational waves from current-carrying cosmic strings
Authors: Auclair Pierre , Blasi Simone , Brdar Vedran , Schmitz Kai
Published: April 2023

Cosmic strings are predicted by many Standard Model extensions involving the cosmological breaking of a symmetry with nontrivial first homotopy group and represent a potential source of primordial gravitational waves (GWs).
Present efforts to model the GW signal from cosmic strings are often based on minimal models, such as, e.g., the Nambu-Goto action that describes cosmic strings as exactly one-dimensional objects without any internal structure.

In order to arrive at more realistic predictions, it is therefore necessary to consider nonminimal models that make an attempt at accounting for the microscopic properties of cosmic strings.

With this goal in mind, we derive in this paper the GW spectrum emitted by current-carrying cosmic strings (CCCSs), which may form in a variety of cosmological scenarios.

Our analysis is based on a generalized version of the velocity-dependent one-scale (VOS) model, which, in addition to the mean velocity and correlation length of the string network, also describes the evolution of a chiral (light-like) current.

As we are able to show, the solutions of the VOS equations imply a temporarily growing fractional cosmic-string energy density, Ωcs.

This results in an enhanced GW signal across a broad frequency interval, whose boundaries are determined by the times of generation and decay of cosmic-string currents.

Our findings have important implications for GW experiments in the Hz to MHz band and motivate the construction of realistic particle physics models that give rise to large currents on cosmic strings.
Questions on calculation of primordial power spectrum with large spikes: the resonance model case
Authors: Inomata Keisuke , Braglia Matteo , Chen Xingang
Published: April 2023

Inflationary models predicting a scale-dependent large amplification of the density
perturbations have recently attracted a lot of attention because the amplified perturbations can
seed a sizable amount of primordial black holes (PBHs) and stochastic background of gravitational
waves (GWs). While the power spectra in these models are computed based on the linear equation of
motion, it is not obvious whether loop corrections are negligible when such a large amplification
occurs during inflation. In this paper, as a first step to discuss the loop corrections in such
models, we use the in-in formalism and calculate the one-loop scalar power spectrum numerically
and analytically in an illustrative model where the density perturbations are resonantly amplified
due to oscillatory features in the inflaton potential. Our calculation is technically new in that
the amplified perturbations are numerically taken into account in the in-in formalism for the
first time. In arriving at our analytical estimates, we highlight the role that the Wronskian
condition of perturbations, automatically satisfied in our model, plays in obtaining the correct
estimates. In addition, the analytical estimates show that the contribution originating from the
quantum nature of the perturbations in the loop can be dominant. We also discuss the necessary
conditions for subdominant loop corrections in this model. We find that, for the typical
parameter space leading to the 𝒪(107) amplification of the power spectrum required for
a sufficient PBH production, the one-loop power spectrum dominates over the tree-level one,
indicating the breakdown of the perturbation theory.
An extended laser cavity centered at 780 nm for high-resolution laser spectroscopy applications
Authors: Álvarez J , Pimienta J , Mercado E , Sarmiento R
Published: April 2023

Laser diodes (LDs) working in free mode present different types of effects such as shift and broadening of the spectral peak, determined by external factors such as temperature, electric current or mechanical vibrations, which are undesirable when required in applications such as high resolution laser spectroscopy, metrology or laser cooling. To reduce the width of the spectral emission peak of a laser, different configurations or optical setups are used, among which one of the most effective is to extend the optical resonator of the LD and use optical feedback, either with the help of a partially reflective mirror or with a diffraction grating. In this work, we present the design, construction, and characterization of a compact extended-cavity diode laser (ECDL) in Littrow configuration. The ECDL was machined on an aluminum block using computerized numerical control. It operates at a wavelength of 780.24 nm with a maximum output power of 35 mW. The results showed a spectral linewidth of 340 kHz using the self-heterodyne technique and a frequency stability of 0.47 MHz when the cavity was stabilized with an atomic reference.
Systematic studies on the nuclear parton distribution with photon and hadron productions in nuclear collisions at the LHC*
Authors: Li Xing-Long , Zhu Ya , Zhang Xiao-Ming , Zhou Dai-Cui
Published: April 2023

A systematic study on the impact of widely-used nuclear-modified parton distribution function (nPDF) parameterizations on the production of direct photons and charged hadrons is performed by employing a next-to-leading order Monte Carlo event generator JETPHOX in hadronic collisions at LHC energies. The nuclear modification factors of photon and charged hadron productions are studied in three types of collision systems, i.e., small (

and

), medium

, and large

, in a wide rapidity acceptance. The results illustrate that the direct photon production process is a sensitive probe to decipher the difference of the nPDF parameterization implementations, which provides new insights for the experimental measurements to refine the nuclear modifications of the parton distributions. To provide a benchmark for searching for quark gluon plasma in the upcoming small system measurements at LHC energies, we carry out detailed studies on the cold nuclear matter effect in

collisions. Our outcomes show that the cold nuclear matter effects are negligible for the charged hadron production in

collisions, which can be used as a baseline to subtract the initial state contribution.
Identifying Pauli blockade regimes in bilayer graphene double quantum dots
Authors: Mukherjee Ankan , Muralidharan Bhaskaran
Published: April 2023

Recent experimental observations of current blockades in 2D material quantum-dot platforms have opened new avenues for spin and valley-qubit processing. Motivated by experimental results, we construct a model capturing the delicate interplay of Coulomb interactions, inter-dot tunneling, Zeeman splittings, and intrinsic spin–orbit coupling in a double quantum dot (DQD) structure to simulate the Pauli blockades. Analyzing the relevant Fock-subspaces of the generalized Hamiltonian, coupled with the density matrix master equation technique for transport across the setup, we identify the generic class of blockade mechanisms. Most importantly, and contrary to what is widely recognized, we show that conducting and blocking states responsible for the Pauli-blockades are a result of the coupled effect of all degrees of freedom and cannot be explained using the spin or the valley pseudo-spin only. We then numerically predict the regimes where Pauli blockades might occur, and, to this end, we verify our model against actual experimental data and propose that our model can be used to generate data sets for different values of parameters with the ultimate goal of training on a machine learning algorithm. Our work provides an enabling platform for a predictable theory-aided experimental realization of single-shot readout of the spin and valley states on DQDs based on 2D-material platforms.
Insights to the fracture toughness, damage tolerance, electronic structure, and magnetic properties of carbides M2C (M = Fe, Cr)
Authors: Duan Junwen , Hou Tingping , Zhang Dong , Wu Kaiming
Published: April 2023

The fracture toughness, damage tolerance, electronic structure, and magnetic properties of M2C (M = Fe, Cr) carbides were analyzed using first-principles calculations. Calculations of formation energy and modulus of elasticity indicate that a Cr/Fe ratio of 1/3 is a critical threshold which triggers a significant increase in the corresponding stability and related mechanical properties. Cr atomic content enhances the crack resistance, while Cr has a significantly detrimental effect on damage resistance. The electronic properties demonstrated that the Cr atom content enhances the metallic, ionic and covalent bonding. Furthermore, the reduction in the coordination number of Fe atoms is the main reason for the reduction in the local magnetic moment of the low-spin Cr atoms, which is strongly supported by the electronic structure. These studies provide detailed insights into Cr-containing carbides, providing valuable theoretical and technological information for the knowledge-based design and prediction of the mechanical properties of chromium-containing iron-based materials.
Local field enhancement factor of spheroidal core–shell nanocomposites with passive and active dielectric cores
Authors: Hirpha Tolasa Tamasgen , Bergaga Garoma Dhaba , Ali Belayneh Mesfin , Shewamare Gebre Sisay
Published: April 2023

We studied the effects of depolarization factor (L), metal fraction (p), and dielectric function of host matrix (ε

h
) on the local field enhancement factor (LFEF) of spheroidal core–shell nanocomposites (NCs) with passive and active dielectric cores. Solving Laplace’s equations in the quasi-static limit, we obtained expressions of electric potentials for spheroidal core–shell NCs. Then, by introducing L and the Drude-Sommerfeld model into these expressions, we derived the equation of LFEF in the core of spheroidal core–shell NCs. The results show that whether L, p, and/or ε

h
vary or kept constant, LFEF of the spheroidal core–shell NCs possesses two sets of peaks with passive dielectric core, whereas only a set of peak is observed with active dielectric core. In NCs with passive dielectric core, an increase in any of these parameters resulted in a more pronounced LFEF peaks in the first set of resonances. With both passive and active dielectric cores, increasing L increases the peaks of LFEF of spheroidal core–shell NCs, whereas increasing p shows decreasing tendency on the peaks of LFEF of the same material with active dielectric core. Moreover, the highest peak of LFEF is obtained by increasing L than p or ε

h
indicating that change in the geometry of spheroidal core–shell NCs has the highest effect on the LFEF than the metal concentration and host dielectric function. With the same increase in ε

h
, intensities of LFEF of the spheroidal core–shell NCs decrease when the dielectric core is passive and increase when the dielectric core is active. Briefly, the number and intensities of peaks of LFEF of spheroidal core–shell NCs vary greatly when its core is made either passive or active dielectric. Furthermore, by changing parameters like L, p, and ε

h
, adjustable LFEF could be obtained and used for applications in optical sensing, nonlinear optics, and quantum optics.
Study of imitative micro pit morphology evaluation
Authors: Panmongkol Picha , Rojviriya Catleya , Phung-on Isaratat
Published: April 2023

This study examined the imitative micro pit formation of pitting corrosion on 304 stainless steel under electrochemical control in a 3.0% NaCl solution. Results demonstrated that the micro pits changed from a conical to a cap shape during growth, indicating that their evolution in shape and growth did not follow the same morphology over time. Additionally, the piecewise polynomial method was employed to compare real-time micro pit growth morphology evolution with current density, which was consistent with cross-sectional images of actual micro pits, enabling the separation of the pitting corrosion stages. Furthermore, 3D images obtained from SRXTM were similar to cross-sectional images of real micro pits, further validating the technique’s usefulness in studying micro pits.
Effect of holding time and Ti/B molar ratio on microstructure and mechanical properties of in-situ TiB2/Al composites fabricated by mixed salt reaction
Authors: Xie Hui , Cao Yuanbao
Published: April 2023

In this study, in situ TiB2/Al composites is fabricated by K2TiF6 and KBF4 systems. The effects of process parameters on the size, distribution and morphology of in situ TiB2 particles, as well as the microstructure and mechanical properties of the composite is analyzed. When the mixed salts is added at 750 °C, TiB2 particles are short rods. When the temperature is higher than 825 °C, TiB2 particles are cubic columns and hexagonal columns. When the reaction temperature is 825 °C, the grain refinement of the composite is most obviously. When the holding time is 80 min, TiB2 particles are uniformly distributed in the matrix and the size is less than 2 μm. The ultimate tensile strength, yield strength and elongation of the composite reach the maximum values of 230 MPa, 125 MPa and 9.5%. When the holding time is 110 min, TiB2 particles agglomerate at the grain boundary, and the mechanical properties of the composites decrease. When the Ti/B molar ratio is 1/1, in addition to forming TiB2 particles, large size hard brittle phase TiAl3 appear in the microstructure. When the Ti/B molar ratio is 1/2.2, the formation of hard brittle phase TiAl3 can be inhibited, TiB2 particles are uniformly distributed in the matrix and the grain refinement is most obviously. The ultimate tensile strength, yield strength and elongation of the composite reach the maximum values of 225 MPa, 110 MPa and 8.5%. When the Ti/B molar ratio is 1/3, the unreacted residual mixed salts appear in the microstructure of the composite, and the residual mixed salts impurities exist at the interface between TiB2 particles and the matrix, so reduce the mechanical properties of the composite.
Feasibility of using bio-enzyme as an admixture in reactive powder concrete
Authors: Raja MA , Judes Sujatha S
Published: April 2023

Utilizing bio-based elements as cement additives has a significant impact on the production of extremely durable and sustainable concrete composites. In the present research work, the effect of a bio-enzyme (Terrazyme) on the strength, durability, and microstructure of RPC was researched at various proportions of Terrazyme (TZ) as binder replacement (0, 0.5, 1, 1.5, 2, and 2.5%). The migration of water and transport properties of concrete are accessed through measurement of the water absorption and gas permeability. Results show that the use of TZ in RPC slightly reduced the compressive strength, and the reduction was more significant at high replacement levels when subjected to water curing. A significant reduction in the permeability of RPC with a relatively low permeability coefficient is obtained even at higher dosages of TZ in autoclaved RPC specimens with greater mechanical strength. In addition, greater chloride penetration with the prolongation of ages is obtained. The inclusion of TZ can not only enhance the waterproofing and penetration resistance of RPC but also achieve economic and ecological benefits.
The effect of variable labels on deep learning models trained to predict breast density
Authors: Squires Steven , Harkness Elaine F , Evans D Gareth , Astley Susan M
Published: April 2023

Purpose. High breast density is associated with reduced efficacy of mammographic screening and increased risk of developing breast cancer. Accurate and reliable automated density estimates can be used for direct risk prediction and passing density related information to further predictive models. Expert reader assessments of density show a strong relationship to cancer risk but also inter-reader variation. The effect of label variability on model performance is important when considering how to utilise automated methods for both research and clinical purposes. Methods. We utilise subsets of images with density labels from the same 13 readers and 12 reader pairs, and train a deep transfer learning model which is used to assess how label variability affects the mapping from representation to prediction. We then create two end-to-end models: one that is trained on averaged labels across the reader pairs and the second that is trained using individual reader scores, with a novel alteration to the objective function. The combination of these two end-to-end models allows us to investigate the effect of label variability on the model representation formed. Results. We show that the trained mappings from representations to labels are altered considerably by the variability of reader scores. Training on labels with distribution variation removed causes the Spearman rank correlation coefficients to rise from 0.751 ± 0.002 to either 0.815 ± 0.026 when averaging across readers or 0.844 ± 0.002 when averaging across images. However, when we train different models to investigate the representation effect we see little difference, with Spearman rank correlation coefficients of 0.846 ± 0.006 and 0.850 ± 0.006 showing no statistically significant difference in the quality of the model representation with regard to density prediction. Conclusions. We show that the mapping between representation and mammographic density prediction is significantly affected by label variability. However, the effect of the label variability on the model representation is limited.
Nanoparticles reinforced joints produced using friction stir welding: a review
Authors: Singh Tanvir
Published: April 2023

Fusion welding processes do not find attention due to their restriction to use for certain grades of materials and alloys. Friction Stir welding (FSW) or the solid-state joining process has proven to be a more efficient process for the welding of metal-matrix reinforced composite butt joints by employing various combinations of reinforcement particles and base matrices compared to the fusion welding process. Due to the solid-state nature of the FSW process, no melting of base material would occur which leads to no toxic fumes, low energy consumption, environmentally friendly, and ease of operation that makes FSW a more versatile welding process for aerospace, automobile, and transportation industries. However, the challenges in joining metal matrix reinforced composites remain even with a substantial advancement in the process made during current years. This review article outlines a brief overview of the state of art of metal matrix reinforced welds joined using FSW. More emphasis with critical evaluation has been done on the (a) macrostructural and microstructural characteristics of a metal matrix reinforced welds which merely depend on the plasticized material flow and reinforcement particles behavior and its difficulty for uniform distribution of reinforcement particles in the weld zone based on the combination of reinforcement particles and the metal matrix materials, (b) assessment of mechanical properties of the metal matrix reinforced welds those are directly interdependent on the selection of process parameters by which the grain refinement and their reinforcement particles distribution depend that leads to changes in such properties, and (c) fracture and wear properties of the metal matrix reinforced welds which again depends on the reinforcement particles and the metal matrix materials combination. The conclusions of this review are ended up with recommendations for the directions for future research.
Effects of eastern vs. central Pacific El Niño on Northern Hemisphere photosynthetic seasonality
Authors: Dannenberg Matthew P , Johnston Miriam R
Published: April 2023

The El Niño–Southern Oscillation (ENSO) affects many climatic controls on vegetation activity, driving interannual variation in timing (phenology) and magnitude of terrestrial carbon uptake. However, the climatic effects of ENSO can differ for sea surface temperature (SST) anomalies primarily centered in the eastern vs. central Pacific (EP and CP, respectively). Here, we examine the extent to which EP and CP SST anomalies affect Northern Hemisphere photosynthetic seasonality and whether their effects differ. Using two decades of satellite near-infrared reflectance of vegetation (NIRv) and FLUXNET2015 gross primary production, we estimated annual 0.05° start and end of growing season timing corresponding to the onset and offset of photosynthetic activity, as well as peak NIRv magnitude as a proxy for peak growing season productivity. We find that correlations between Northern Hemisphere photosynthetic timing/magnitude and ENSO differ for EP- and CP-centered SST anomalies, though in many regions the effects and differences between them are quite small. Warmer SSTs generally led to an earlier start of the photosynthetic season, especially in North America and parts of Eurasia. However, the magnitude (and even direction) of the relationships between start of season and SST differed for CP- and EP-dominated events. Correlations of both peak NIRv magnitude and end of season timing with ENSO tended to be smaller in magnitude and more regionally idiosyncratic, though with strong evidence of different effects of CP and EP SSTs. In southern North America, CP SSTs (but not EP SSTs) were positively associated with peak NIRv, while in boreal regions of North America and Eurasia, CP SSTs were negatively associated with peak NIRv (despite small positive associations with EP SSTs). Differences between the effects of EP and CP SST anomalies suggest that short-term vegetation forecasts based on aggregate ENSO indices could be improved by separately considering the EP and CP components.
The Existence of Designs via Iterative Absorption: Hypergraph 𝐹-designs for Arbitrary 𝐹
Authors: Glock Stefan , Kühn Daniela , Lo Allan , Osthus Deryk
Published: April 2023

We solve the existence problem for

F
F

-designs for arbitrary

r
r

-uniform hypergraphs 

F
F

. This implies that given any

r
r

-uniform hypergraph 

F
F

, the trivially necessary divisibility conditions are sufficient to guarantee a decomposition of any sufficiently large complete

r
r

-uniform hypergraph into edge-disjoint copies of 

F
F

, which answers a question asked e.g. by Keevash. The graph case

r
=
2

r=2

was proved by Wilson in 1975 and forms one of the cornerstones of design theory. The case when 

F
F

is complete corresponds to the existence of block designs, a problem going back to the 19th century, which was recently settled by Keevash. In particular, our argument provides a new proof of the existence of block designs, based on iterative absorption (which employs purely probabilistic and combinatorial methods).

Our main result concerns decompositions of hypergraphs whose clique distribution fulfills certain regularity constraints. Our argument allows us to employ a ‘regularity boosting’ process which frequently enables us to satisfy these constraints even if the clique distribution of the original hypergraph does not satisfy them. This enables us to go significantly beyond the setting of quasirandom hypergraphs considered by Keevash. In particular, we obtain a resilience version and a decomposition result for hypergraphs of large minimum degree.
Quantitative bounds for critically bounded solutions to the Navier-Stokes equations
Authors: Tao Terence
Published: April 2023

We revisit the regularity theory of Escauriaza, Seregin, and Šverák for solutions to the three-dimensional Navier-Stokes equations which are uniformly bounded in the critical

L
x
3

(

R

3

)

L^3_x(\mathbb {R}^3)

norm. By replacing all invocations of compactness methods in these arguments with quantitative substitutes, and similarly replacing unique continuation and backwards uniqueness estimates by their corresponding Carleman inequalities, we obtain quantitative bounds for higher regularity norms of these solutions in terms of the critical

L
x
3

L^3_x

bound (with a dependence that is triple exponential in nature). In particular, we show that as one approaches a finite blowup time

T
∗

T_*

, the critical

L
x
3

L^3_x

norm must blow up at a rate

(
log
⁡
log
⁡
log
⁡

1

T
∗

−
t

)
c

(\log \log \log \frac {1}{T_*-t})^c

or faster for an infinite sequence of times approaching

T
∗

T_*

and some absolute constant

c
>
0

c>0

.
Recent advances in differential expression analysis for single-cell RNA-seq and spatially resolved transcriptomic studies
Authors: Guo Xiya , Ning Jin , Chen Yuanze , Liu Guoliang , Zhao Liyan , Fan Yue , Sun Shiquan
Published: April 2023

Differential expression (DE) analysis is a necessary step in the analysis of single-cell RNA sequencing (scRNA-seq) and spatially resolved transcriptomics (SRT) data. Unlike traditional bulk RNA-seq, DE analysis for scRNA-seq or SRT data has unique characteristics that may contribute to the difficulty of detecting DE genes. However, the plethora of DE tools that work with various assumptions makes it difficult to choose an appropriate one. Furthermore, a comprehensive review on detecting DE genes for scRNA-seq data or SRT data from multi-condition, multi-sample experimental designs is lacking. To bridge such a gap, here, we first focus on the challenges of DE detection, then highlight potential opportunities that facilitate further progress in scRNA-seq or SRT analysis, and finally provide insights and guidance in selecting appropriate DE tools or developing new computational DE methods.
Photoprotection and skin cancer education: the experiences of renal transplant recipients, a qualitative study – why the ‘personal touch’ is important
Authors: Griffin Laoise , O’Reilly Pauline , Murphy Marcus , Prendergast Gemma , Pender Emily , Tummon Olga , Griffin Matthew , Laing Mary
Published: April 2023

Our qualitative study of the skin cancer information delivered to renal transplant recipients (RTRs) highlighted that we must find the optimum time when things are settled for patients to absorb this information. Knowing and trusting the person delivering the information was welcomed by participants and more likely to influence behaviour, as was the healthcare professional who took time to consider the individuality of recipients. Knowledge gaps have been uncovered and require consideration, including a predominant concern of melanoma rather than squamous cell carcinoma, and a reliance on sunscreen and not other sun protective measures. Renal colleagues are highly considered by RTRs and well placed to deliver interventions
Eigenvector centrality and its variability over time are promising indicators of alterations in brain function due to early amyloid deposition
Authors: Skouras Stavros
Published: April 2023

This scientific commentary refers to ‘Eigenvector centrality dynamics are related to Alzheimer’s disease pathological changes in non-demented individuals’, by Lorenzini et al. (https://doi.org/10.1093/braincomms/fcad088).
Implementation of Low-Barrier Human Immunodeficiency Virus Care: Lessons Learned From the Max Clinic in Seattle
Authors: Dombrowski Julia C , Ramchandani Meena S , Golden Matthew R
Published: April 2023

Low-barrier care (LBC) for people with human immunodeficiency virus (HIV) is a differentiated service delivery strategy to engage people in HIV treatment who are not well-engaged in conventionally organized HIV medical care. The LBC approach is flexible, but experience suggests that the intervention has distinct core components. This review summarizes our experience implementing one model of LBC, the Max Clinic in Seattle; describes the core components of the intervention; and presents a framework for implementing low-barrier HIV care with the goal of providing a practical guide for clinical and public health leaders seeking to implement a new LBC program. A systematic approach to addressing key factors during LBC implementation can support practitioners to design an LBC approach that fits the local context while maintaining essential elements of the intervention.
Leveraging Unique Chromosomal Microarray Probes to Accurately Detect Copy Number at the Highly Homologous 15q15.3 Deafness-Infertility Syndrome Locus
Authors: Sack Laura M , Mertens Lauren , Murphy Elissa , Hutchinson Laura , Giersch Anne B S , Mason-Suares Heather
Published: April 2023

Background

Biallelic deletions at 15q15.3, including STRC and CATSPER2, cause autosomal recessive deafness-infertility syndrome (DIS), while biallelic deletions of STRC alone cause nonsyndromic hearing loss. These deletions are among the leading genetic causes of mild–moderate hearing loss, but their detection using chromosomal microarray (CMA) is impeded by a tandem duplication containing highly homologous pseudogenes. We sought to assess copy number variant (CNV) detection in this region by a commonly-employed CMA platform.

Methods

Twenty-two specimens with known 15q15.3 CNVs, determined by droplet digital PCR (ddPCR), were analyzed by CMA. To investigate the impact of pseudogene homology on CMA performance, a probe-level analysis of homology was performed, and log2 ratios of unique and pseudogene-homologous probes compared.

Results

Assessment of 15q15.3 CNVs by CMA compared to ddPCR revealed 40.9% concordance, with frequent mis-assignment of zygosity by the CMA automated calling software. Probe-level analysis of pseudogene homology suggested that probes with high homology contributed to this discordance, with significant differences in log2 ratios between unique and pseudogene-homologous CMA probes. Two clusters containing several unique probes could reliably detect CNVs involving STRC and CATSPER2, despite the noise of surrounding probes, discriminating between homozygous vs heterozygous losses and complex rearrangements. CNV detection by these probe clusters showed 100% concordance with ddPCR.

Conclusions

Manual analysis of clusters containing unique CMA probes without significant pseudogene homology improves CNV detection and zygosity assignment in the highly homologous DIS region. Incorporation of this method into CMA analysis and reporting processes can improve DIS diagnosis and carrier detection.
Mobility and Security Aware Real-Time Task Scheduling in Fog-Cloud Computing for IoT Devices: A Fuzzy-Logic Approach
Authors: Ali Hala S , Sridevi R
Published: April 2023

This paper aims to improve the overall task processing time of mobile real-time Internet of Things (IoT) applications in fog-cloud computing, considering the various resource and security requirements along with the time constraints of the task. Fog computing extends the cloud resources to serve the IoT devices at the network edge. In such a scenario, deciding whether the tasks should be processed at the fog layer or submitted to the cloud is critical. Moreover, for real-time applications, the mobility of IoT devices and the limited bandwidth available at the edge devices endanger the low processing time of the task. Besides, the security demands of some IoT applications (i.e. healthcare) require processing the tasks by specific fog or cloud servers to assure confidentiality of information, which may also delay the task processing time. Therefore, we first address the mobility issue by proposing three different algorithms that work on allocating the mobile IoT device to the appropriate edge device (i.e. fog gateway), considering the distance and bandwidth load factors. Then, we offer a novel task scheduling algorithm that uses fuzzy logic to optimize the distribution of tasks between the fog and cloud layers, considering the task security requirements. The algorithm selects the proper processing unit to execute the task in the fog layer by exploiting the task demands (i.e. computation, storage, bandwidth, security) and deadline. Results demonstrate that considering the factors of distance and available bandwidth load while allocating the IoT device to the fog gateway improves the task processing time better than adopting one aspect. Results also show that our proposed scheduling algorithm outperforms other existing algorithms regarding makespan, turnaround time, success ratio and processing time metrics.
Vascular mechanisms of post-COVID-19 conditions: Rho-kinase is a novel target for therapy
Authors: Sykes Robert A , Neves Karla B , Alves-Lopes Rhéure , Caputo Ilaria , Fallon Kirsty , Jamieson Nigel B , Kamdar Anna , Legrini Assya , Leslie Holly , McIntosh Alasdair , McConnachie Alex , Morrow Andrew , McFarlane Richard W , Mangion Kenneth , McAbney John , Montezano Augusto C , Touyz Rhian M , Wood Colin , Berry Colin
Published: April 2023

Background

In post-coronavirus disease-19 (post-COVID-19) conditions (long COVID), systemic vascular dysfunction is implicated, but the mechanisms are uncertain, and the treatment is imprecise.

Methods and results

Patients convalescing after hospitalization for COVID-19 and risk factor matched controls underwent multisystem phenotyping using blood biomarkers, cardiorenal and pulmonary imaging, and gluteal subcutaneous biopsy (NCT04403607). Small resistance arteries were isolated and examined using wire myography, histopathology, immunohistochemistry, and spatial transcriptomics. Endothelium-independent (sodium nitroprusside) and -dependent (acetylcholine) vasorelaxation and vasoconstriction to the thromboxane A2 receptor agonist, U46619, and endothelin-1 (ET-1) in the presence or absence of a RhoA/Rho-kinase inhibitor (fasudil), were investigated. Thirty-seven patients, including 27 (mean age 57 years, 48% women, 41% cardiovascular disease) 3 months post-COVID-19 and 10 controls (mean age 57 years, 20% women, 30% cardiovascular disease), were included. Compared with control responses, U46619-induced constriction was increased (P = 0.002) and endothelium-independent vasorelaxation was reduced in arteries from COVID-19 patients (P < 0.001). This difference was abolished by fasudil. Histopathology revealed greater collagen abundance in COVID-19 arteries {Masson's trichrome (MT) 69.7% [95% confidence interval (CI): 67.8–71.7]; picrosirius red 68.6% [95% CI: 64.4–72.8]} vs. controls [MT 64.9% (95% CI: 59.4–70.3) (P = 0.028); picrosirius red 60.1% (95% CI: 55.4–64.8), (P = 0.029)]. Greater phosphorylated myosin light chain antibody-positive staining in vascular smooth muscle cells was observed in COVID-19 arteries (40.1%; 95% CI: 30.9–49.3) vs. controls (10.0%; 95% CI: 4.4–15.6) (P < 0.001). In proof-of-concept studies, gene pathways associated with extracellular matrix alteration, proteoglycan synthesis, and viral mRNA replication appeared to be upregulated.

Conclusion

Patients with post-COVID-19 conditions have enhanced vascular fibrosis and myosin light change phosphorylation. Rho-kinase activation represents a novel therapeutic target for clinical trials.
Effects and Mechanisms of CEO Quality in Public Education
Authors: Lavy Victor , Rachkovski Genia , Boiko Adi
Published: April 2023

‘CEOs’ of public schools in many countries have authority and responsibilities that can greatly affect the quality of schooling. This paper estimates the impact of CEOs on student outcomes in Israeli elementary schools. We estimate CEO quality in two ways—once using schools that do not switch CEOs and once using schools that do. We show that switches are exogenous and are not correlated with potential outcomes. CEO quality positively affects students’ test scores and behavioural outcomes, with pronounced effects for disadvantaged schools. Potential mechanisms show that high-quality CEOs lead to improvements in school priorities, working procedures and violence reduction.
Evolution, coronary artery bypass surgery and outcomes of right ventricular dysfunction in ischaemic cardiomyopathy
Authors: Zhou Zhuoming , Jian Bohao , Fu Guangguo , Liu Haoliang , Huang Yang , Feng Zicong , Huang Suiqing , Li Huayang , Liang Mengya , Wu Zhongkai
Published: April 2023

OBJECTIVES

Whether the presence or evolution of right ventricular dysfunction (RVD) affects the prognosis and the therapeutic choice between coronary artery bypass grafting (CABG) or medical therapy alone in patients with ischaemic cardiomyopathy (ICM) remains unclear. We investigate the prognostic and therapeutic implications of RVD in patients with ICM.

METHODS

Patients with baseline echocardiographic right ventricular (RV) assessment were included from the Surgical Treatment of Ischaemic Heart Failure trial. The primary outcome was all-cause mortality.

RESULTS

Of 1212 patients enrolled in the Surgical Treatment of Ischaemic Heart Failure trial, 1042 patients were included, with 143 (13.7%) mild RVD and 142 (13.6%) moderate-to-severe RVD. After a median follow-up of 9.8 years, compared with patients with normal RV function, patients with RVD had a higher risk of mortality [mild RVD: adjusted hazard ratio (aHR) 1.32; 95% confidence interval (CI) 1.06–1.65; moderate-to-severe RVD: aHR, 1.75; 95% CI 1.40–2.19]. Among patients with moderate-to-severe RVD, CABG provided no additional survival benefits compared to medical therapy alone (aHR: 0.98; 95% CI: 0.67–1.43). Among 746 patients with pre- and post-therapeutic RV assessment, a gradient risk for death increased from patients with consistent normal RV function, to patients with recovery from RVD, new-onset RVD and persistent RVD.

CONCLUSIONS

RVD was associated with a worse prognosis in patients with ICM, and CABG provided no additional survival benefits to patients with moderate-to-severe RVD. The evolution of RV function had important prognostic implications, which emphasized the importance of both pre- and post-therapeutic RV assessment.
Disruption and selection: the income gradient in mortality among natives and migrants in Sweden
Authors: Östergren Olof , Rehnberg Johan , Lundberg Olle , Miething Alexander
Published: April 2023

Background

The income gradient in mortality is generated through an interplay between socio-economic processes and health over the life course. International migration entails the displacement of an individual from one context to another and may disrupt these processes. Furthermore, migrants are a selected group that may adopt distinct strategies and face discrimination in the labour market. These factors may have implications for the income gradient in mortality. We investigate whether the income gradient in mortality differs by migrant status and by individual-level factors surrounding the migration event.

Methods

We use administrative register data comprising the total resident population in Sweden aged between 30 and 79 in 2015 (n = 5.7 million) and follow them for mortality during 2015–17. We estimate the income gradient in mortality by migrant status, region of origin, age at migration and country of education using locally estimated scatterplot smoothing and Poisson regression.

Results

The income gradient in mortality is less steep among migrants compared with natives. This pattern is driven by lower mortality among migrants at lower levels of income. The gradient is less steep among distant migrants than among close migrants, migrants that arrived as adults compared with children and migrants that received their education in Sweden as opposed to abroad.

Conclusions

Our results are consistent with the notion that income inequalities in mortality are generated through life-course processes that may be disrupted by migration. Data restrictions prevent us from disentangling life-course disruption from selection into migration, discrimination and labour market strategies.
Different species of Bradyrhizobium from symbiovars genistearum and retamae nodulate the endemic Retama dasycarpa in the High Atlas Mountains
Authors: Lamrabet Mouad , Chaddad Zohra , Bouhnik Omar , Alami Soufiane , Kaddouri Kaoutar , Bennis Meryeme , Lamin Hanane , Mnasri Bacem , Bourgerie Sylvain , Morabito Domenico , Abdelmoumen Hanaa , Bedmar Eulogio J , Missbah El Idrissi Mustapha
Published: April 2023

Retama dasycarpa is an endemic Retama species native to the cold semi-arid bioclimates of the High Atlas Mountains in Morocco. In this work, we analyzed the diversity of the microsymbionts nodulating this plant and their different phenotypic and symbiotic characteristics. Phylogenetic analysis of the 16S rRNA gene revealed that the tested isolates clustered in the Bradyrhizobium genus. Multilocus sequence analyses of four housekeeping genes (recA, gyrB, glnII and atpD) for 12 selected strains grouped them into four clusters close to B. lupini USDA 3051T, B. frederickii CNPSo 3446T, B. valentinum LmjM3T and B. retamae Ro19T. The individual phylogenies of these core genes and the symbiotic genes nodC, nodA and nifH were congruent. These isolates showed a broad host range, being able to nodulate different legume hosts, such as R. sphaerocarpa, R. monosperma, Lupinus luteus, Cytisus grandiflorus andChamaecytisus albidus, but not Phaseolus vulgaris or Glycine max. They all had a similar metabolic capacity, using the majority of the carbohydrates and amino acids tested as sole sources of carbon and nitrogen. Furthermore, out of the 12 selected strains, some displayed plant growth-promoting features, with six of them solubilizing phosphate and three of them producing siderophores. The present work provides, for the first time, a detailed description about the microsymbionts associated with the endemic legume R. dasycarpa.
Polarity of c-di-GMP synthesis and degradation
Authors: Kreiling Vanessa , Thormann Kai M
Published: April 2023

The bacterial cell pole has long been recognized as a defined compartment for enzymatic activities that are important or even vital for the cell. Polarity of diguanylate cyclases and phosphodiesterases, enzymes that synthesize and degrade the second messenger c-di-GMP, has now been demonstrated for several bacterial systems. Here we review these polar regulatory systems and show how the asymmetry of c-di-GMP production and turnover in concert with different modes of activation and deactivation creates heterogeneity in cellular c-di-GMP levels. We highlight how this heterogeneity generates a diverse set of phenotypic identities or states and how this may benefit the cell population, and we discuss reasons why the polarity of c-di-GMP signaling is probably widespread among bacteria.
Causes and consequences of linkage disequilibrium among transposable elements within eukaryotic genomes
Authors: Roze Denis
Published: April 2023

Sex and recombination can affect the dynamics of transposable elements (TEs) in various ways: while sex is expected to help TEs to spread within populations, the deleterious effect of ectopic recombination among transposons represents a possible source of purifying selection limiting their number. Furthermore, recombination may also increase the efficiency of selection against TEs by reducing selective interference among loci. In order to better understand the effects of recombination and reproductive systems on TE dynamics, this article provides analytical expressions for the linkage disequilibrium among TEs in a classical model in which TE number is stabilized by synergistic purifying selection. The results show that positive linkage disequilibrium is predicted in infinite populations despite negative epistasis, due to the effect of the transposition process. Positive linkage disequilibrium may substantially inflate the variance in the number of elements per genome in the case of partially selfing or partially clonal populations. Finite population size tends to generate negative linkage disequilibrium (Hill–Robertson effect), the relative importance of this effect increasing with the degree of linkage among loci. The model is then extended in order to explore how TEs may affect selection for recombination. While positive linkage disequilibrium generated by transposition generally disfavors recombination, the Hill–Robertson effect may represent a non-negligible source of indirect selection for recombination when TEs are abundant. However, the direct fitness cost imposed by ectopic recombination among elements generally drives the population towards low-recombination regimes, at which TEs cannot be maintained at a stable equilibrium.
Predictors of Adherence to Continuous Positive Airway Pressure in Older Adults With Apnea and Amnestic Mild Cognitive Impairment
Authors: Richards Kathy C , Lozano Alicia J , Morris Jennifer , Moelter Stephen T , Ji Wenyan , Vallabhaneni Vani , Wang Yanyan , Chi Luqi , Davis Eric M , Cheng Cindy , Aguilar Vanessa , Khan Sneha , Sankhavaram Mira , Hanlon Alexandra L , Wolk David A , Gooneratne Nalaka
Published: April 2023

Background

Almost 60% of adults with amnestic mild cognitive impairment (aMCI) have obstructive sleep apnea (OSA). Treatment with continuous positive airway pressure (CPAP) may delay cognitive decline, but CPAP adherence is often suboptimal. In this study, we report predictors of CPAP adherence in older adults with aMCI who have increased odds of progressing to dementia, particularly due to Alzheimer’s disease.

Methods

The data are from Memories 2, “Changing the Trajectory of Mild Cognitive Impairment with CPAP Treatment of Obstructive Sleep Apnea.” Participants had moderate to severe OSA, were CPAP naïve, and received a telehealth CPAP adherence intervention. Linear and logistic regression models examined predictors.

Results

The 174 participants (mean age 67.08 years, 80 female, 38 Black persons) had a mean apnea–hypopnea index of 34.78, and 73.6% were adherent, defined as an average of ≥4 hours of CPAP use per night. Only 18 (47.4%) Black persons were CPAP adherent. In linear models, White race, moderate OSA, and participation in the tailored CPAP adherence intervention were significantly associated with higher CPAP use at 3 months. In logistic models, White persons had 9.94 times the odds of adhering to CPAP compared to Black persons. Age, sex, ethnicity, education, body mass index, nighttime sleep duration, daytime sleepiness, and cognitive status were not significant predictors.

Conclusions

Older patients with aMCI have high CPAP adherence, suggesting that age and cognitive impairment should not be a barrier to prescribing CPAP. Research is needed to improve adherence in Black patients, perhaps through culturally tailored interventions.
Purchasing for high-quality care using National Health Insurance: evidence from Zambia
Authors: Osei Afriyie Doris , Masiye Felix , Tediosi Fabrizio , Fink Günther
Published: April 2023

Improving the quality of care is essential for progress towards universal health coverage. Health financing arrangements offer opportunities for governments to incentivize and reward improvements in the quality of care provided. This study examines the extent to which the purchasing arrangements established within Zambia’s new National Health Insurance can improve equitable access to high-quality care. We adopt the Strategic Purchasing Progress and the Lancet Commission for High-Quality Health Systems frameworks to critically examine the broader health system and the purchasing dimensions of this insurance scheme and its implications for quality care. We reviewed policy documents and conducted 31 key-informant interviews with stakeholders at national, subnational and health facility levels. We find that the new health insurance could boost financial resources in higher levels of care, improve access to high-cost interventions, improve care experiences for its beneficiaries and integrate the public and private sectors. Our findings also suggest that health insurance will likely improve some aspects of structural quality but may not be able to influence process and outcome measures of quality. It is also not clear if health insurance will improve the efficiency of service delivery and whether the benefits realized will be distributed equitably. These potential limitations are attributable to the existing governance and financial challenges, low investments in primary care and shortcomings in the design and implementation of the purchasing arrangements of health insurance. Although Zambia has made progress in a short span, there is a need to improve its provider payment mechanisms, and monitoring and accounting for a higher quality of care.
Hyperbolic Anderson Model 2: Strichartz Estimates and Stratonovich Setting
Authors: Chen Xia , Deya Aurélien , Song Jian , Tindel Samy
Published: April 2023

We study a wave equation in dimension $d\in \{1,2\}$ with a multiplicative space-time Gaussian noise. The existence and uniqueness of the Stratonovich solution is obtained under some conditions imposed on the Gaussian noise. The strategy is to develop some Strichartz-type estimates for the wave kernel in weighted Besov spaces, by which we can prove the well-posedness of an associated Young-type equation. Those Strichartz bounds are of independent interest.