Standard Field Research Articles

Influence of a powder-forming additive on the physical-mechanical properties and structure of a ceramic material

The purpose of the study was to explore the effect of various pore-forming additives on the porosity and permeability of alumina ceramic material. Analysis of mineralogical, particle size distribution and chemical composition of raw materials and ceramics samples was performed using standard research methods, JCM-6000 (JEOL) and field emission scanning electron microscopy (FESEM) microscopes, LW600LT, x-ray diffractometer Rigaku D/max-RA, Hitachi SU-70 and Pore Master. The microstructure of the composite ceramic material in all experiments demonstrated the presence of numerous cross-sectionally elongated pores, which proves the dependence of the pore-forming structure on the shape of the pore-forming agent. The high permeability of samples with lignin is due to the improved plastic properties of the clays. By increasing the clay content from 5 to 10 wt.% it was possible to increase the sintering density of the samples and reduce their overall porosity. The permeability porosity increases with the introduction of more urea, and the strength of the samples is then at its maximum. Samples with the addition of lignin demonstrated resistance to mechanical stress and high permeability. The study identifies the prospects of using crystallised urea and lignin from manufacturing waste as a pore former, which will allow the establishment of environmentally friendly ceramic materials with high permeability and durability and solve the problem of atmospheric pollution.

Veltman criteria in the beyond standard model effective field theory of a complex scalar triplet

Veltman criteria in the beyond standard model effective field theory of a complex scalar triplet

Carrollian Conformal Fields and Flat Holography

The null conformal boundary I of Minkowski spacetime M plays a special role in scattering theory, as it is the locus where massless particle states are most naturally defined. We construct quantum fields on I, which create these massless states from the vacuum and transform covariantly under Poincaré symmetries. Because the latter symmetries act as Carrollian conformal isometries of I, these quantum fields are Carrollian conformal fields. This group theoretic construction is intrinsic to I by contrast to existing treatments in the literature. However, we also show that the standard relativistic massless quantum fields in M, when pulled back to I, provide a realisation of these Carrollian conformal fields. This correspondence between bulk and boundary fields should constitute a basic entry in the dictionary of flat holography. Finally, we show that I provides a natural parametrisation of the massless particles as described by irreducible representations of the Poincaré group and that in an appropriate conjugate basis, they indeed transform like Carrollian conformal fields.

Tree-level UV completions for NRSMEFT d = 6 and d = 7 operators

We study ultra-violet completions for operators in standard model effective field theory extended with right-handed neutrinos (NRSMEFT). Using a diagrammatic method, we generate systematically lists of possible tree-level completions involving scalars, fermions or vectors for all operators at d = 6 and d = 7, which contain at least one right-handed neutrino. We compare our lists of possible UV models to the ones found for pure SMEFT. We also discuss how the observation of LNV processes via NRSMEFT operators at the LHC can be related to Majorana neutrino masses of the standard model neutrinos.

A new parameter-free fault location approach for power distribution systems

A power distribution system (PDS) is a crucial component of the electrical power system. Faults frequently occur over the PDS; which can usually cause damage to the entire power system and need time and effort to detect, locate and eliminate them. The proposed parameter-free fault location algorithms used measurements from two or multi-terminals of the power system, which are not always available, especially in power distribution systems, where measurements are usually available only from a single-end.This paper proposes a new parameter-free fault location approach in a PDS. The approach is mainly based on the magnetic behavior of the power distribution system before and during faulty conditions. The suggested approach only takes advantage of post-fault voltage and current measurement from one-terminal disregarding line parameters. Computer simulations using standard and real field power distribution systems are reported and have shown quite encouraging results.

Evidence for the charge asymmetry in pp → toverline{t} production at sqrt{s} = 13 TeV with the ATLAS detector

Inclusive and differential measurements of the top–antitop ( toverline{t} ) charge asymmetry {A}_{textrm{C}}^{toverline{t}} and the leptonic asymmetry {A}_{textrm{C}}^{ell overline{ell}} are presented in proton–proton collisions at sqrt{s} = 13 TeV recorded by the ATLAS experiment at the CERN Large Hadron Collider. The measurement uses the complete Run 2 dataset, corresponding to an integrated luminosity of 139 fb−1, combines data in the single-lepton and dilepton channels, and employs reconstruction techniques adapted to both the resolved and boosted topologies. A Bayesian unfolding procedure is performed to correct for detector resolution and acceptance effects. The combined inclusive toverline{t} charge asymmetry is measured to be {A}_{textrm{C}}^{toverline{t}} = 0.0068 ± 0.0015, which differs from zero by 4.7 standard deviations. Differential measurements are performed as a function of the invariant mass, transverse momentum and longitudinal boost of the toverline{t} system. Both the inclusive and differential measurements are found to be compatible with the Standard Model predictions, at next-to-next-to-leading order in quantum chromodynamics perturbation theory with next-to-leading-order electroweak corrections. The measurements are interpreted in the framework of the Standard Model effective field theory, placing competitive bounds on several Wilson coefficients.

Accuracy of aspirin prophylaxis for preeclampsia prevention documentation within a large administrative dataset.

Low-dose aspirin prophylaxis is recommended for women at risk of preeclampsia. Capturing aspirin prophylaxis within administrative databases can be challenging since it is an over-the-counter medication. The Better Outcome Registry and Network (BORN) database, a perinatal health registry in Ontario, Canada, includes a formal variable that captures aspirin prophylaxis for preeclampsia. This variable has not been formally validated. To assess the accuracy of the aspirin prophylaxis variable in the BORN database against an electronic medical record (EMR). This validation study comprised 200 randomly selected women who had a livebirth at St. Michael's Hospital (SMH) in Toronto, Ontario, from January 2018 to July 2022. Recorded aspirin prophylaxis in pregnancy and maternal sociodemographic characteristics were independently extracted by two abstractors. Accuracy of aspirin prophylaxis use in the BORN database was compared to that in the SMH EMR, expressed as sensitivity, specificity, positive (PPV) and negative predictive values (NPV), Cohen's kappa (κ), and overall percent agreement, with 95% confidence intervals (CI). Sensitivity analyses were performed to account for missing or unclear aspirin prophylaxis use. Among 200 women, 24 (12.0%) received aspirin prophylaxis - 12.5% within the SMH EMR and 8.0% in the BORN database. Women using aspirin were older (37.0 vs 33.0 years) and had higher median gravidity (3 vs. 2). Sensitivity and specificity of the BORN aspirin prophylaxis variable were 62.5% (95% CI 40.6, 81.2) and 100.0% (95% CI 97.3, 100.0), respectively. The corresponding positive and negative predictive values were 100.0% (95% CI 78.2, 100.0), and 93.8% (95% CI 88.6, 97.1), respectively. Cohen's κ was 0.74 (95% CI 0.58, 0.90), and overall percent agreement was 94.4% (95% CI 87.1, 100.0). Aspirin use within the BORN database, based on a standard variable field, appears accurate enough for the potential use in epidemiological studies of aspirin prophylaxis for preeclampsia or as a covariate in related studies.

Toward a complete description of b → uℓ− overline{nu} within the Weak Effective Theory decays

We fit the available data on exclusive semileptonic b → uℓ− overline{nu} decays within the Standard Model and in the Weak Effective Theory. Assuming Standard Model dynamics, we find left|{V}_{ub}right|={3.59}_{-0.12}^{+0.13}times {10}^{-3} . Lifting this assumption, we obtain stringent constraints on the coefficients of the ubℓν sector of the Weak Effective Theory. Performing a Bayesian model comparison, we find that a beyond the Standard Model interpretation is favoured over a Standard Model interpretation of the available data. We provide a Gaussian mixture model that enables the efficient use of our fit results in subsequent analyses beyond the Standard Model, within and beyond the framework of the Standard Model Effective Field Theory.

LEX-EFT: the Light Exotics Effective Field Theory

We propose the creation of a Light Exotics Effective Field Theory (LEX-EFT) catalog. LEX-EFT is a generic framework to capture all interactions between the Standard Model (SM) and all (or at least a large class of) theoretically allowed exotic states beyond the Standard Model (bSM), indexed by their SM and bSM charges. These states are light enough to be on or nearly on shell in some collider processes. This framework, which subsumes beyond the Standard Model paradigms as generally as possible, is meant to extend recent successful implementations of bSM EFTs and complement e.g. the Standard Model Effective Field Theory (SMEFT), which can capture the off-shell effects of exotic fields. In this work, we review a general method for the construction of a complete list of gauge-invariant operators involving SM interactions with light exotics via iterative tensor product decomposition, up to the desired order in mass dimension. Each operator is characterized by specific Clebsch-Gordan coefficients determined by the charge flow; we show how this charge flow affects the range of EFT validity and cross sections associated with an effective operator. We create an example catalog of exotic scalars coupling to SM gauge boson pairs, and we highlight some operators with exotic weak SU(2)L charges that can produce spectacular LHC phenomenology. We further demonstrate the utility of the LEX-EFT approach with several examples of effects on kinematic distributions and cross sections that would not be captured by EFTs agnostic to the exotic degrees of freedom and may evade the main inclusive collider searches tailored to the existing preferred set of standard bSM theories.

νDoBe — A Python tool for neutrinoless double beta decay

We present νDoBe, a Python tool for the computation of neutrinoless double beta decay (0νββ) rates in terms of lepton-number-violating operators in the Standard Model Effective Field Theory (SMEFT). The tool can be used for automated calculations of 0νββ rates, electron spectra and angular correlations for all isotopes of experimental interest, for lepton-number-violating operators up to and including dimension 9. The tool takes care of renormalization-group running to lower energies and provides the matching to the low-energy effective field theory and, at lower scales, to a chiral effective field theory description of 0νββ rates. The user can specify different sets of nuclear matrix elements from various many-body methods and hadronic low-energy constants. The tool can be used to quickly generate analytical and numerical expressions for 0νββ rates and to generate a large variety of plots. In this work, we provide examples of possible use along with a detailed code documentation. The code can be accessed through:GitHub: https://github.com/OScholer/nudobeOnline User-Interface: https://oscholer-nudobe-streamlit-4foz22.streamlit.app/

Exorcising the ghost condensate dark energy with a sextic dispersion relation

The universe's current acceleration is a pretty recent phenomenon in cosmological time scales. This means that the modes that have left our horizon since the beginning of the contemporary acceleration phase, have not really reached the exact IR limit. Noting this observation, we reconsider the possibility of having a ghost condensate as dark energy with a sixth-order dispersion relation. Looking at the three-point function of such a theory, we obtain the constraints on the coefficient of the sixth-order dispersion relation to avoid strong coupling. We notice that such a constraint can be easily satisfied, without fine-tuning. Such a ghost condensate, if coupled to the standard model fields, induces a constant Lorentz-violating spin-dependent force, which can gravitate or anti-gravitate. The Newtonian potential is modified with an oscillatory behavior at distance scale MPl/M2 at the time scale MPl2/M3, where M2 is the expectation value of the ghost field velocity, i.e. 〈ϕ˙〉=M2.

Probing lepton flavor violation at Circular Electron-Positron Colliders

Lepton flavor violation is one of the cleanest probes of physics beyond the standard model. In this work, we explore the sensitivity of the process e+e− → τμ to new physics above the TeV scale at the proposed circular electron-positron colliders FCC-ee and CEPC. We compute the e+e− → τμ cross-section in the Standard Model Effective Field Theory and assess the relevant backgrounds. We compare our sensitivity projections to existing and expected constraints from tau decays and Z decays and find that the future electron-positron colliders provide competitive probes of new physics. We highlight the complementarity of searches for resonant e+e−→ Z → τμ production on the Z pole and searches for non-resonant e+e−→ τμ at higher center-of-mass energies.

Tear biomarkers for Alzheimer’s disease screening and diagnosis (the TearAD study): design and rationale of an observational longitudinal multicenter study

BackgroundAlzheimer’s disease (AD) is the most common cause of dementia, and due to increasing life expectancy the number of patients is expected to grow. The diagnosis of AD involves the use of biomarkers determined by an amyloid PET scan or cerebrospinal fluid analyses that are either invasive or expensive, and not available in each hospital, thus limiting their usage as a front-line screener. The TearAD study aims to use tear fluid as a potential source for AD biomarkers. In previous reports, we demonstrated that AD biomarkers amyloid-beta and tau, are measurable in tear fluid and are associated with disease severity and neurodegeration. This study aims to validate previous results in a larger cohort and evaluate the diagnostic accuracy of tear biomarkers to discriminate between individuals with and without neurodegeneration as determined by hippocampal atrophy.MethodsThe TearAD study is an observational longitudinal multi-center study that will enroll 50 cognitively healthy controls, 50 patients with subjective cognitive decline, 50 patients with mild cognitive impairment and 50 patients with AD dementia from the memory clinic. Participants will be examined at baseline, after one year, and after two years follow-up. Study assessments include neuropsychological tests and ophthalmic examination. All participants will receive a MRI scan, and a subset of the study population will undergo cerebral spinal fluid collection and an amyloid PET scan. Tear fluid will be collected with Schirmer strips and levels of Aβ38, Aβ40, Aβ42, t-tau and p-tau in tear fluid will be determined using multiplex immunoassays. Blood samples will be collected from all participants. Images of the retina will be obtained with a standard, hyperspectral and ultra-wide field fundus camera. Additionally, macular pigment optical density will be measured with the macular pigment reflectometer, and cross-sectional images of the retina will be obtained through optical coherence tomography imaging.DiscussionThe TearAD study will provide insight into the potential diagnostic use of tear biomarkers as a minimally invasive and low cost tool for the screening and diagnosis of AD.Trial registrationRetrospectively registered at clinicaltrials.gov (NCT05655793).

Analytic Preconditioners for Decoupled Potential Integral Equations and Wideband Analysis of Scattering From PEC Objects

Many integral equations used to analyze scattering, such as the standard combined field integral equation (CFIE), are not well-conditioned for a wide range of frequencies and multi-scale geometries. There has been significant effort to alleviate this problem. A more recent one is using a set of decoupled potential integral equations (DPIE). These equations have been shown to be robust at low frequencies and immune to topology breakdown. But they mimic the ill-conditioning behavior of CFIE at high frequencies. This paper addresses this deficiency through new Calderón-type identities derived from the Vector Potential Integral Equation (VPIE). We construct novel analytic preconditioners for the vector potential integral equation (VPIE) and scalar potential integral equation (SPIE) constrained to perfect electric conductors (PEC). These new formulations are wide-band well-conditioned and converge rapidly for multi-scale geometries. This is demonstrated though a number of examples that use analytic and piecewise basis sets.

A calibration method of ground-airborne frequency domain electromagnetic receving system based on magnetic source excitation

In the ground-airborne frequency domain electromagnetic detection, the receving system converts the magnetic field signal into an electrical signal representing the magnetic field signal. In order to accurately obtain the relationship between the magnetic field signal and the electrical signal, it is necessary to avoid the influence of environment and other factors on the system accuracy through on-site calibration. This requires high calibration accuracy, simple operation, portable equipment and strong adaptability to the environment. However, the existing calibration methods put forward higher requirements for instruments and environment. For example, the calibration of uniform magnetic field generated by Helmholtz coil needs to shield external magnetic field interference. In this paper, an overall calibration method of measurement system based on magnetic source excitation is proposed to meet the requirements of electromagnetic field accurate measurement in ground-airborne frequency domain. Firstly, based on the electromagnetic measurement method in ground-airborne frequency domain, the overall calibration method and principle of the detection system are introduced. Then, based on the computable standard magnetic field generated by the magnetic source transmitting coil, determine the measured voltage obtained by the receiving system, get the calibration coefficient of the receiving system. At last,the source of standard uncertainty related to calibration is analyzed, and the uncertainty is evaluated. In addition, the method is verified by comparing the calibration results with those obtained by Braunbeck coil calibration.

The impact ofvaping ethanol-containing electronic cigarette liquids onroadside impairment investigations.

Legal professionals and others have suggested that vaping electronic cigarettes (e-cigs) prior to or during ethanol breath testing may produce false positives. Preliminary breath tests (PBTs) and evidentiary breath tests (EBTs) measure ethanol in exhaled breath and standardized field sobriety tests (SFSTs) are used to assess impairment. Ethanol has been identified in e-cig liquids (e-liquids). Presented are a series of experiments designed to determine the mechanics of vaping ethanol using an e-cig and the effects of vaping ethanol on the SFSTs and breath tests used by law enforcement officers (LEO). Twelve participants (five females, age: 21-32 and seven males, age: 21-55), vaped either one or ten puffs of an e-liquid (0% or 20% ethanol). LEOs assessed impairment using SFSTs (12 and 42 min), PBTs (<1, 27, 32, 37 and 57 min) and EBTs (2, 29, 34, 39 and 59 min) post-vaping. A self-assessment test was administered post-vaping (22 and 52 min). Baseline responses for all measures were collected prior to vaping. Results demonstrated that ethanol in the e-liquids was aerosolized by e-cigs and produced particles that could reach the deep lung tissue based on mean-mass diameter. Ethanol was detected by PBT <3 min after participants vaped one (0.007-0.030 g/210 L) or ten puffs (013-0.074 g/210 L) of a 20% ethanol e-liquid. Ethanol was not detected by PBT at any subsequent time point. Ethanol was not detected by the EBT under any condition. Impairment was not indicated by the SFST. Some subjective effects were reported, but few statistically significant differences between conditions were indicated. A wait period prior to ethanol breath testing is not always mandated, depending on jurisdiction, or observed in all applications, such as workplace testing. The results demonstrate that a wait period must be employed to prevent vaping-related false-positive breath ethanol results.

Multidimensional Drivers of Mercury Distribution in Global Surface Soils: Insights from a Global Standardized Field Survey.

Soil stores a large amount of mercury (Hg) that has adverse effects on human health and ecosystem safety. Significant uncertainties still exist in revealing environmental drivers of soil Hg accumulation and predicting global Hg distribution owing to the lack of field data from global standardized analyses. Here, we conducted a global standardized field survey and explored a holistic understanding of the multidimensional environmental drivers of Hg accumulation in global surface soils. Hg content in surface soils from our survey ranges from 3.8 to 618.2 μg kg-1 with an average of 74.0 μg kg-1 across the globe. Atmospheric Hg deposition, particularly vegetation-induced elemental Hg0 deposition, is the major source of surface soil Hg. Soil organic carbon serves as the major substrate for sequestering Hg in surface soils and is significantly influenced by agricultural management, litterfall, and elevation. For human activities, changing land-use could be a more important contributor than direct anthropogenic emissions. Our prediction of a new global Hg distribution highlights the hot spots (high Hg content) in East Asia, the Northern Hemispheric temperate/boreal regions, and tropical areas, while the cold spots (low Hg content) are in arid regions. The holistic understanding of multidimensional environmental drivers helps to predict the Hg distribution in global surface soils under a changing global environment.

Searches for new physics with boosted top quarks in the MadAnalysis 5 and Rivet frameworks

High-momentum top quarks are a natural physical system in collider experiments for testing models of new physics, and jet substructure methods are key both to exploiting their largest decay mode and to assuaging resolution difficulties as the boosted system becomes increasingly collimated in the detector. To be used in new-physics interpretation studies, it is crucial that related methods get implemented in analysis frameworks allowing for the reinterpretation of the results of the LHC such as MadAnalysis 5 and Rivet. We describe the implementation of the HEPTopTagger algorithm in these two frameworks, and we exemplify the usage of the resulting functionalities to explore the sensitivity of boosted top reconstruction performance to new physics contributions from the Standard Model Effective Field Theory. The results of this study lead to important conclusions about the implicit assumption of Standard-Model-like top quark decays in associated collider analyses, and for the prospects to constrain the Standard Model Effective Field Theory via kinematic observables built from boosted semi-leptonic tbar{t} events selected using HEPTopTagger.

Spin and orbital angular momentum of coherent photons in a waveguide

Spin angular momentum of a photon corresponds to a polarisation degree of freedom of lights, and such that various polarisation properties are coming from macroscopic manifestation of quantum-mechanical properties of lights. An orbital degree of freedom of lights is also manipulated to form a vortex of lights with orbital angular momentum, which is also quantised. However, it is considered that spin and orbital angular momentum of a photon cannot be split from the total orbital angular momentum in a gauge-invariant way. Here, we revisit this issue for a coherent monochromatic ray from a laser source, propagating in a waveguide. We obtained the helical components of spin and orbital angular momentum by the correspondence with the classical Ponyting vector. By applying a standard quantum field theory using a coherent state, we obtained the gauge-independent expressions of spin and orbital angular momentum operators. During the derivations, it was essential to take a finite cross-sectional area into account, which leads the finite longitudinal component along the direction of the propagation, which allows the splitting. Therefore, the finite mode profile was responsible to justify the splitting, which was not possible as far as we were using plane-wave expansions in a standard theory of quantum-electrodynamics (QED). Our results suggest spin and orbital angular momentum are well-defined quantum-mechanical freedoms at least for coherent photons propagating in a waveguide and in a vacuum with a finite mode profile.

Colonization and coexistence of non‐native ants on a model Atlantic island

AbstractAimsColonization by non‐native ants represents one of the gravest potential threats to island ecosystems. It is necessary to identify general mechanisms by which non‐native species are able to colonize and persist in order to inform future prevention and management. We studied a model‐island assemblage of 17 non‐native ant species with aim of identifying the spatial source of introductions and assessing how such a diversity of species are able to coexist.LocationData were collected on Ascension Island: an ideal study system for its intermediate area, compact shape, spatial heterogeneity, lack of native ant species, and availability of non‐native ant records dating back to the 1800s.MethodsWe collected over 47,000 individual ants from 73 sites using a range of baited traps and survey techniques. We combined this novel data with past occurrence records in order to determine whether human settlements have historically been the source of ant introductions and to quantify the mean rate at which species have dispersed across the island. Analysis of standardized field data revealed the extent to which ants were partitioning ecological niche space via (1) habitat separation, (2) fine‐scale resource partitioning and (3) climatic heterogeneity.ResultsAnts were radiating at a linear rate of approximately 0.5 km2 per year from human settlements on this island, with the most widespread species having been introduced earliest. After accounting for incomplete colonization, we found no evidence to suggest habitat separation between species. Instead, we found significant niche separation through resource partitioning and weather‐dependent activity patterns.Main ConclusionsOur results indicate that non‐native ants can coexist in very close proximity and are therefore capable of existing at great diversity on even small islands. It is inevitable that ant colonization will continue without increased biosecurity measures, habitat restoration around settlements and conservation of native species populations.