Non-standard Models Research Articles

Constraining on the non-standard cosmological models combining the observations of high-redshift quasars and BAO

In this work, we studied four types of cosmological models with different mechanisms driving the accelerated expansion of the universe, include Braneworld models, Chaplygin Gas models, Emergent Dark Energy models, and cosmological torsion models. Considering that the dynamics of these models at low redshifts are very similar and difficult to distinguish, we used the latest and largest UV and X-ray measurements of quasars (QSOs) observations covering the range of redshift 0.009<z<7.5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.009<z<7.5$$\\end{document}. However, the high intrinsic dispersion of this sample and the degeneracy between cosmological model parameters, we added 2D-BAO and 3D-BAO datasets to help us constrain the parameters of these cosmological models. Our results suggest that standard cold dark matter scenario may not be the best cosmological model preferred by the high-redshift observations. The Generalized Chaplygin Gas (GCG) and cosmological constant plus torsion (named Case II) models perform best by Akaike Information Criterion (AIC), but the Λ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\Lambda $$\\end{document}CDM is the best cosmological model preferred by Bayesian Information Criterion (BIC). Our work also supports that the Phenomenologically Emergent Dark Energy and cosmological torsion models may alleviate the Hubble tension, the reported value of the Hubble constant obtained from QSO+BAO datasets combination lies between Planck 2018 observations and local measurements from the SH0ES collaboration, while other cosmological models all support that the Hubble constant tends to be closer to recent Planck 2018 results, but these model are penalized by information criterion.

Accurate Nonstandard Path Integral Models for Arbitrary Dielectric Boundaries in 2-D NS-FDTD Domains.

An efficient path integral (PI) model for the accurate analysis of curved dielectric structures on coarse grids via the two-dimensional nonstandard finite-difference time-domain (NS-FDTD) technique is introduced in this paper. In contrast to previous PI implementations of the perfectly electric conductor case, which accommodates orthogonal cells in the vicinity of curved surfaces, the novel PI model employs the occupation ratio of dielectrics in the necessary cells, providing thus a straightforward and instructive means to treat an assortment of practical applications. For its verification, the reflection from a flat plate and the scattering from a cylinder using the PI model are investigated. Results indicate that the featured methodology can enable the reliable and precise modeling of arbitrarily shaped dielectrics in the NS-FDTD algorithm on coarse grids.

Analytical approach to piezoelectric model synthesis with the use of Cauer’s method for system design

Background Piezoceramic materials have unique property which enables direct and bilateral conversion between mechanical and electrical energy. This ability facilitates significant miniaturisation of technology and opens many opportunities in design of new actuators and energy harvesters. Mathematical modelling of piezoelectric modules is notoriously hard due to complex constitutive equations defining mechanical and electrical energy conversion. Methods The article presents research on a new synthesis method based on the Cauer’s method. Mechanical damping is introduced with the use of Rayleigh’s approximation. A discrete electromechanical model is formed based on the Mason’s piezoelectric model. The proposed approach allows modelling of piezoelectric systems based on a set of characteristic frequencies. The method allows a more general approach to the problem of modelling new systems, as opposed to application-oriented methods seen in literature. A non-standard model analysis method using edge graphs and structural numbers is also verified as a potential alternative for matrix-based method. The authors compare their precision and computation requirements. Results The structural method of mechanical model analysis gave identical results as the reference matrix method. However, the non-classical algorithm took much longer to calculate and was using more memory. The electromechanical model analysis has shown an error of 5% in comparison to resonance frequencies taken from a reference plate specification. The calculated magnitude of displacement was well above the capability of a 3.5mm thick piezoelectric plate. Conclusions The synthesis method presented in this paper allows synthesizing piezoelectric cascade models based on limited information in form of characteristic frequencies. Currently this method allows a coarse approximation of the real piezoelectric parameters with limited number of inputs. The additional method of analysis based on structural numbers offers a promising alternative to matrix calculations but requires a more thorough investigation of the computational power required to determine whether it can compete with existing algorithms.

Flow of a colloidal solution in an orthogonal rheometer

The flow of a colloidal solution between two parallel disks rotating with the same angular velocity about two non-coincident axes was studied. The problem has been approached from two perspectives, the first wherein the stress is expressed in terms of a power-law of kinematical quantities, and the second wherein we consider a non-standard model where the symmetric part of the velocity gradient is given by a power-law of the stress. For a range of power-law exponents, the class of models are non-invertible. By varying the material and geometric parameters, changes in the flow behavior at different Reynolds numbers were analyzed. We find that pronounced boundary layers develop even at low Reynolds numbers depending on the power-law exponents. The new class of stress power-law fluids and fluids that exhibit limiting stress also show the ability to develop boundary layers.

Indiscernibles and satisfaction classes in arithmetic

AbstractWe investigate the theory Peano Arithmetic with Indiscernibles ($$\textrm{PAI}$$ PAI ). Models of $$\textrm{PAI}$$ PAI are of the form $$({\mathcal {M}},I)$$ ( M , I ) , where $${\mathcal {M}}$$ M is a model of $$\textrm{PA}$$ PA , I is an unbounded set of order indiscernibles over $${\mathcal {M}}$$ M , and $$({\mathcal {M}},I)$$ ( M , I ) satisfies the extended induction scheme for formulae mentioning I. Our main results are Theorems A and B following. Theorem A.Let$${\mathcal {M}}$$ M be a nonstandard model of$$\textrm{PA}$$ PA of any cardinality. $$\mathcal {M }$$ M has an expansion to a model of $$\textrm{PAI}$$ PAI iff$$ {\mathcal {M}}$$ M has an inductive partial satisfaction class. Theorem A yields the following corollary, which provides a new characterization of countable recursively saturated models of $$\textrm{PA}$$ PA : Corollary.A countable model$${\mathcal {M}}$$ M of $$\textrm{PA}$$ PA is recursively saturated iff $${\mathcal {M}}$$ M has an expansion to a model of $$\textrm{PAI}$$ PAI . Theorem B.There is a sentence $$\alpha $$ α in the language obtained by adding a unary predicateI(x) to the language of arithmetic such that given any nonstandard model $${\mathcal {M}}$$ M of$$\textrm{PA}$$ PA of any cardinality, $${\mathcal {M}}$$ M has an expansion to a model of $$\text {PAI}+\alpha $$ PAI + α iff$${\mathcal {M}}$$ M has a inductive full satisfaction class.

Triangulation, incommensurability, and conditionalization

Abstract We present a new justification for methodological triangulation (MT), the practice of using different methods to support the same scientific claim. Unlike existing accounts, our account captures cases in which the different methods in question are associated with, and rely on, incommensurable theories. Using a nonstandard Bayesian model, we show that even in such cases, a commitment to the minimal form of epistemic conservatism, captured by the rigidity condition that stands at the basis of Jeffrey’s conditionalization, supports the practice of MT.

Harnessing Manycore Processors with Distributed Memory for Accelerated Training of Sparse and Recurrent Models

Current AI training infrastructure is dominated by single instruction multiple data (SIMD) and systolic array architectures, such as Graphics Processing Units (GPUs) and Tensor Processing Units (TPUs), that excel at accelerating parallel workloads and dense vector matrix multiplications. Potentially more efficient neural network models utilizing sparsity and recurrence cannot leverage the full power of SIMD processor and are thus at a severe disadvantage compared to today's prominent parallel architectures like Transformers and CNNs, thereby hindering the path towards more sustainable AI. To overcome this limitation, we explore sparse and recurrent model training on a massively parallel multiple instruction multiple data (MIMD) architecture with distributed local memory. We implement a training routine based on backpropagation though time (BPTT) for the brain-inspired class of Spiking Neural Networks (SNNs) that feature binary sparse activations. We observe a massive advantage in using sparse activation tensors with a MIMD processor, the Intelligence Processing Unit (IPU) compared to GPUs. On training workloads, our results demonstrate 5-10x throughput gains compared to A100 GPUs and up to 38x gains for higher levels of activation sparsity, without a significant slowdown in training convergence or reduction in final model performance. Furthermore, our results show highly promising trends for both single and multi IPU configurations as we scale up to larger model sizes. Our work paves the way towards more efficient, non-standard models via AI training hardware beyond GPUs, and competitive large scale SNN models.

Short-term test for the toxicogenomic assessment of ecotoxic modes of action in Myriophyllum spicatum

In environmental risk assessment of substances, the 14-day growth inhibition test following OECD test guideline 239 is employed to assess toxicity in the macrophyte Myriophyllum spicatum. Currently, this test evaluates physiological parameters and does not allow the identification of the mode of action (MoA) by which adverse effects are induced. However, for an improved ecotoxicity assessment of substances, knowledge about their ecotoxic MoA in non-target organisms is required. It has previously been suggested that the identification of gene expression changes can contribute to MoA identification. Therefore, we developed a shortened three-day assay for M. spicatum including the transcriptomic assessment of global gene expression changes and applied this assay to two model substances, the herbicide and photosynthesis inhibitor bentazone and the pharmaceutical and HMG-CoA reductase inhibitor atorvastatin. Due to the lack of a reference genome for M. spicatum we performed a de novo transcriptome assembly followed by a functional annotation to use the toxicogenomic results for MoA discrimination. The gene expression changes induced by low effect concentrations of these substances were used to identify differentially expressed genes (DEGs) and impaired biological functions for the respective MoA. We observed both concentration-dependent numbers and differentiated patterns of DEGs for both substances. While bentazone impaired genes involved in the response to reactive oxygen species as well as light response, and also genes involved in developmental processes, atorvastatin exposure led to a differential regulation of genes related to brassinosteroid response as well as potential metabolic shifts between the mevalonate and methyl erythritol 4-phosphate pathway. Based on these responses, we identified biomarker candidates for the assessment of MoA in M. spicatum. Utilizing the shortened assay developed in this study, the investigation of the identified biomarker candidates may contribute to the development of future MoA-specific screening approaches in the ecotoxicological hazard prediction using aquatic non-standard model organisms.

Locally and globally uniform approximations for ruin probabilities of a nonstandard bidimensional risk model with subexponential claims

Locally and globally uniform approximations for ruin probabilities of a nonstandard bidimensional risk model with subexponential claims

Population genetic simulation: Benchmarking frameworks for non-standard models of natural selection.

Population genetic simulation has emerged as a common tool for investigating increasingly complex evolutionary and demographic models. Software capable of handling high-level model complexity has recently been developed, and the advancement of tree sequence recording now allows simulations to merge the efficiency and genealogical insight of coalescent simulations with the flexibility of forward simulations. However, frameworks utilizing these features have not yet been compared and benchmarked. Here, we evaluate various simulation workflows using the coalescent simulator msprime and the forward simulator SLiM, to assess resource efficiency and determine an optimal simulation framework. Three aspects were evaluated: (1) the burn-in, to establish an equilibrium level of neutral diversity in the population; (2) the forward simulation, in which temporally fluctuating selection is acting; and (3) the final computation of summary statistics. We provide typical memory and computation time requirements for each step. We find that the fastest framework, a combination of coalescent and forward simulation with tree sequence recording, increases simulation speed by over twenty times compared to classical forward simulations without tree sequence recording, although it does require six times more memory. Overall, using efficient simulation workflows can lead to a substantial improvement when modelling complex evolutionary scenarios-although the optimal framework ultimately depends on the available computational resources.

Invisible dark matter decays of a non-Standard Model like CP-even scalar boson

We investigate two extensions of the standard model that include particle dark matter candidates: the Next-to-Two Higgs Doublet Model and the Next-to-minimal Supersymmetric Standard Model. These models feature a non-Standard Model like CP-even scalar with a sub-TeV mass, denoted by H2, among other particles. At a 13 TeV proton–proton collider, the primary production channel for such scalars is via the fusion of a pair of gluons. Subsequently, these scalars can decay invisibly into a pair of dark matter candidates, which can be dominant. In the supersymmetric model, it is possible for the Lightest Supersymmetric Particle (LSP) and Next-to Lightest Supersymmetric Particle (NLSP) to be mass degenerate, leading to quasi-invisible H2 decays to LSP+NLSP and NLSP+NLSP. We present the predictions of both models for this challenging scenario while ensuring compatibility with recent experimental constraints.

Precise large deviations for a multidimensional risk model with regression dependence structure

Abstract In this paper, we consider a nonstandard multidimensional risk model, in which the claim sizes $\{\vec{X}_k, k\ge 1\}$ form an independent and identically distributed random vector sequence with dependent components. By assuming that there exists the regression dependence structure between inter-arrival time and the claim-size vectors, we extend the regression dependence to a more practical multidimensional risk model. For the univariate marginal distributions of claim vectors with consistently varying tails, we obtain the precise large deviation formulas for the multidimensional risk model with the regression size-dependent structure.

Constraining exotic dark matter models with the dark ages 21-cm signal

ABSTRACT The dark ages 21-cm signal is a powerful tool for precision cosmology and probing new physics. We study two non-standard models: an excess radio background (ERB) model (possibly generated by dark matter decay) and the millicharged dark matter (mDM) model. These models were inspired by the possible EDGES detection of a strong global 21-cm absorption during cosmic dawn, but more generally they provide a way to anticipate the potential discovery space. During the dark ages the 21-cm global signal in the ERB model reaches a saturated form for an amplitude Ar = 0.4, where Ar is the radio background intensity at cosmic dawn relative to the cosmic microwave background. This amplitude is one fifth of the minimum required to explain the EDGES signal, and corresponds to just 0.1 per cent of the observed extragalactic background; it would give a signal that can be detected at 5.9σ significance (compared to 4.1σ for the standard signal) and can be distinguished from the standard (no ERB) signal at 8.5σ, all with a 1000 h global signal measurement. The 21-cm power spectrum has potentially more information, but far greater resources would be required for comparable constraints. For the mDM model, over a range of viable parameters, the global signal detection significance would be $4.7-7.2\, \sigma$, and it could be distinguished from standard at $2.2-9.3\, \sigma$. With an array of global signal antennas achieving an effective 100 000 h integration, the significance would be 10× better. Our analysis helps motivate the development of lunar and space-based dark ages experiments.

TO THE PROBLEM OF QUALITY MANAGEMENT OF SOCIO-CULTURAL AND EDUCATIONAL STRUCTURES DURING THE PERIOD OF MARTIAL STATUS

In the article, in line with the task of training specialists in the management of social groups, communities and society in general, an analysis of the problem of quality management of socio-cultural and educational structures during the wartime period was carried out, in particular, the aspect of social responsibility of managers for the results of their own activities was sharpened.&#x0D; Taking into account the Recommendations of the European Parliament and the Council of Europe, the list of competencies of managers of socio-cultural and educational structures is outlined; cultural, social and civic competence is defined as the basis of effective interaction of managers with different age groups of people in the process of professional activity. The main task of specialists of this group is the creation of long-term relations between social communities and society in the conditions of martial law in Ukraine, based on their readiness to quickly search for non-standard models of organizing the social, cultural and educational environment and innovative humanitarian and pedagogical technologies.&#x0D; In line with the requirements for managers of socio-cultural and educational institutions, the signs of management of the 21st century are highlighted (values, norms, traditions, corporate style, image, organizational culture, corporate team spirit); the requirements for specialists were systematized and the best examples of the world experience of implementing sociocultural and educational projects were clarified (the Anglo-American model of management – the diversity and self-sufficiency of sociocultural complexes, well-known initiatives of charitable foundations, volunteer practice; the European model – types of training and internships in the best sociocultural and educational institutions, multicultural education of managers, etc.).&#x0D; A conclusion was made regarding the growth of social responsibility of managers of socio-cultural and educational structures during the wartime period in Ukraine.

Pathologies in satisfaction classes

We study subsets of countable recursively saturated models of PA which can be defined using pathologies in satisfaction classes. More precisely, we characterize those subsets X such that there is a satisfaction class S where S behaves correctly on an idempotent disjunction of length c if and only if c∈X. We generalize this result to characterize several types of pathologies including double negations, blocks of extraneous quantifiers, and binary disjunctions and conjunctions. We find a surprising relationship between the cuts which can be defined in this way and arithmetic saturation: namely, a countable nonstandard model is arithmetically saturated if and only if every cut can be the “idempotent disjunctively correct cut” in some satisfaction class. We describe the relationship between types of pathologies and the closure properties of the cuts defined by these pathologies.

Are we only all by ourselves? A double-level perspective to cope with the insecurity of the nonstandard gig work model

Are we only all by ourselves? A double-level perspective to cope with the insecurity of the nonstandard gig work model

Analytical approach to piezoelectric model synthesis with the use of Cauer’s method for system design

Background: Piezoceramic materials have unique property which enables direct and bilateral conversion between mechanical and electrical energy. This ability facilitates significant miniaturisation of technology and opens many opportunities in design of new actuators and energy harvesters. Mathematical modelling of piezoelectric modules is notoriously hard due to complex constitutive equations defining mechanical and electrical energy conversion. Methods: The article presents research on a new synthesis method based on the Cauer’s method for electrical and mechanical system design. Mechanical damping is introduced with the use of Rayleigh’s approximation. A discrete electromechanical model is formed based on the Mason’s piezoelectric model. As an additional element of the research, a non-standard model analysis method using edge graphs and structural numbers is employed to investigate potential reductions in computational requirements for model analysis. Results: The electromechanical model analysis has shown an error of 5% in relation to the resonance target. The calculated peak in magnitude of displacement at the resonant frequency was well above the capability of a 3.5mm thick piezoelectric plate. The proposed non-standard method of analysis gave identical results in terms of obtained resonance frequencies. The calculated magnitude of vibrations was varying by 50 – 58%. Conclusions: The synthesis method presented in this paper allows an approximation of piezoelectric parameters of a real system based on the created mathematical model. Currently this method is subject to a considerable error in the determined vibration amplitudes of the system, but it allows a coarse approximation of the parameters while having a very limited number of input data. The additional method of analysis based on structural numbers offers a promising alternative to matrix calculations but requires a more thorough investigation of the computational power required to determine whether it can compete with existing algorithms.

Cell scientist to watch – Charlotte Aumeier

ABSTRACT Charlotte Aumeier is an Assistant Professor of Biochemistry at the University of Geneva, Switzerland. After completing her PhD at the University of Bonn, Germany, studying the cytoskeleton of diatoms, Charlotte moved to the University of Grenoble, France, for a postdoc, where she became hooked on microtubules. In 2018, she established her own lab in Geneva, where she and her team work to uncover the dynamics and regulatory mechanisms of microtubule networks using a variety of approaches, including synthetic biology and non-standard model organisms. We spoke with Charlotte over Zoom to learn more about her work, her love of diatoms and how she views some of the biggest challenges of her career as her biggest advantages as a scientist.

Formation of the hydrogen line 21-cm in Dark Ages and Cosmic Dawn: dependences on cosmology and first light

ABSTRACT We analyse the formation of the redshifted hyperfine structure line 21-cm of hydrogen atom in the Dark Ages, Cosmic Dawn, and Reionization epochs. The evolution of the global differential brightness temperature in this line was computed to study its dependence on the values of cosmological parameters and physical conditions in the intergalactic medium. Variations of the depth of the Dark Ages absorption line at z ∼ 80 with variations of the cosmological parameters Ωb, Ωcdm, ΩΛ, ΩK, and H0 are studied. The standard model with post-Planck parameters predicts a value of the differential brightness temperature in the centre of the absorption line ∼30–50 mK. The profile of this line can be quite another in the non-standard cosmological models, which include the annihilating or decaying dark matter, a primordial stochastic magnetic field, etc. It can be shallower or be an emission bump instead of an absorption trough. It is also shown that the position and depth of the Cosmic Dawn absorption line formed at 10 &amp;lt; z &amp;lt; 30, due to the Wouthuysen–Field effect, is mainly defined by the spectral energy distribution of the first sources of light. If reionization occurs at zri = 7 ± 1, then the differential brightness temperature in the centre of this line is ∼80 mK. During the reionization, the emission with an amplitude of ∼20 mK is possible. It is also shown that the temperature, density, and degree of ionization of the baryonic component are decisive in calculating the intensity of the 21-cm absorption/emission line from these epochs.

Probing the electroweak final state in type I 2HDM at the LHC

Most of the experimental searches of the non-Standard Model Higgs boson(s) at the LHC rely on the QCD induced production modes. However, in some beyond Standard Model frameworks, the additional Higgs bosons can have fermiophobic behaviour. The type I two Higgs doublet model considered here is a perfect example where all the additional Higgs bosons exhibit fermiophobic nature over a large region of parameter space. Thus the electroweak productions of these new Higgs bosons are more dominant over the QCD induced processes. In scenarios with light pseuodoscalar (A) which is bound to decay dominantly to bb¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ b\\overline{b} $$\\end{document}, even being fermiophobic, the 4b + W state via pp → H±A → (AW)A → 4b + W and followed by the leptonic decay of W boson can surpass the QCD initiated 4b final state. However, the signal gets overshadowed by large tt¯\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ t\\overline{t} $$\\end{document}+jets background and hence constructing a suitable discriminator based on the signal hypothesis and signal topology is necessary. We devised a χ2 variable as the most suitable signal-background discrimintor to reduce the background by a sizable amount and showed the discovery reach (> 3σ) of the electroweak initiated final state at the LHC.