Earlier Paper Research Articles

On the Fibonacci Tiling and its Modern Ramifications

AbstractIn the last 30 years, the mathematical theory of aperiodic order has developed enormously. Many new tilings and properties have been discovered, few of which are covered or anticipated by the early papers and books. Here, we start from the well‐known Fibonacci chain to explain some of them, with pointers to various generalisations as well as to higher‐dimensional phenomena and results. This should give some entry points to the modern literature on the subject.

Dynamics in Explicit Gradient Elasticity: Material Frame-Indifference, Boundary Conditions and Consistent Euler–Bernoulli Beam Theory

The paper is concerned with the boundary conditions of explicit gradient elasticity of Mindlin’s type in dynamics. It has been argued in an earlier paper that acceleration terms should not be present in the boundary tractions because of objectivity arguments. This is discussed in the present paper in more detail, and it is supplemented by assuming the validity of the principle of material frame indifference. Furthermore, new examples are discussed in order to illustrate that significant differences exist in the responses predicted by boundary tractions with and without acceleration terms.

Enhancement of the NORAD-Atomic-Data Database in Plasma

We report recent enhancements to the online atomic database at the Ohio State University, NORAD-Atomic-Data, that provide various parameters for radiative and collisional atomic processes dominant in astrophysical plasma. NORAD stands for Nahar Osu RADiative. The database belongs to the data sources, especially for the latest works, of the international collaborations of the Opacity Project and the Iron Project. The contents of the database are calculated values for energies, oscillator strengths, radiative decay rates, lifetimes, cross-sections for photoionization, electron-ion recombination cross-sections, and recombination rate coefficients. We have recently expanded NORAD-Atomic-Data with several enhancements over those reported earlier. They are as follows: (i) We continue to add energy levels, transition parameters, cross-sections, and recombination rates for atoms and ions with their publications. (ii) Recently added radiative atomic data contain a significant amount of transition data for photo-absorption spectral features corresponding to the X-ray resonance fluorescence effect, showing prominent wavelength regions of bio-signature elements, such as phosphorus ions, and emission bumps of heavy elements, such as of lanthanides, which may be created in a kilonova event. We are including (iii) collisional data for electron-impact-excitation, (iv) experimental data for energies and oscillator strengths for line formation, (v) experimental cross-sections for photoionization that can be applied for benchmarking and other applications, and (vi) the introduction of a web-based interactive feature to calculate spectral line ratios at various plasma temperature and density diagnostics, starting with our recently published data for P II. We presented a summary description of theoretical backgrounds for the computed data in the earlier paper. With the introduction of experimental results in the new version of NORAD, we present a summary description of measurement of high-resolution photoionization cross-sections at an Advanced Light Source of LBNL synchrotron set-up and briefly discuss other set-ups. These additions should make NORAD-Atomic-Data more versatile for various applications. For brevity, we provide information on the extensions and avoid repetition of data description of the original paper.

A Hardware-Based Orientation Detection System Using Dendritic Computation

Studying how objects are positioned is vital for improving technologies like robots, cameras, and virtual reality. In our earlier papers, we introduced a bio-inspired artificial visual system for orientation detection, demonstrating its superiority over traditional systems with higher recognition rates, greater biological resemblance, and increased resistance to noise. In this paper, we propose a hardware-based orientation detection system (ODS). The ODS is implemented by a multiple dendritic neuron model (DNM), and a neuronal pruning scheme for the DNM is proposed. After performing the neuronal pruning, only the synapses in the direct and inverse connections states are retained. The former can be realized by a comparator, and the latter can be replaced by a combination of a comparator and a logic NOT gate. For the dendritic function, the connection of synapses on dendrites can be realized with logic AND gates. Then, the output of the neuron is equivalent to a logic OR gate. Compared with other machine learning methods, this logic circuit circumvents floating-point arithmetic and therefore requires very little computing resources to perform complex classification. Furthermore, the ODS can be designed based on experience, so no learning process is required. The superiority of ODS is verified by experiments on binary, grayscale, and color image datasets. The ability to process data rapidly owing to advantages such as parallel computation and simple hardware implementation allows the ODS to be desirable in the era of big data. It is worth mentioning that the experimental results are corroborated with anatomical, physiological, and neuroscientific studies, which may provide us with a new insight for understanding the complex functions in the human brain.

Reflexive advocacy: The role of the interviewer in presuppositional interviews in qualitative research

The presuppositional interview in qualitative research requires the researcher to be interviewed about their thoughts, assumptions, and presumptions about their research. Its purpose is to recognise the impact of our thoughts, feelings, and actions in the ways in which we, as the researcher, exists in the research process. In earlier papers, we have discussed the purpose of the presuppositional interview, however, there is little attention in the literature about the person who interviews the researcher about their research, the presuppositional interviewer. The purpose of this paper is to discuss this unique role because the function and conversational structure differs from other types of interviewing. We propose the role of the presuppositional interviewer role is a reflexive advocate, as their engagement is intentionally directed toward supporting the researcher to develop insights about themselves, in the context of their research. The interviewer has no part in the interpretation. Instead, they are engaging in an activity which promotes the need to support and celebrate curiosity, but that remains in the domain of the researcher. To achieve this, we discuss the role and purpose of the presuppositional interviewer and offer practical guidance as to how to interview with presuppositional purpose.
  

Abelian covers of regular hypertopes

Known as thin residually connected incidence geometry, hypertopes extend the framework of abstract polytopes, and can be built from Coxeter groups (not necessarily with linear diagrams). A regular hypertope is a flag-transitive hypertope. In this paper, we present infinite families of regular hypertopes of ranks 5, 6 and 7, in terms of a certain group covering approach (analogous to a method proposed by Conder and the author in an earlier paper on abstract chiral polytopes, but with wider adaptation). Although the illustrative examples within these families are derived from Coxeter groups exhibiting Y-shaped diagrams, this approach is applicable to obtaining regular hypertopes from Coxeter groups with other diagrams, such that the size of the family members grows linearly with entries of their types.

Academic writing and identity: evaluative discourse in academic papers across cohorts of 20th century linguists

Abstract Using a cohort sequential quantitative design and evaluative features drawn from Systemic Functional Grammar, this study investigates diachronic variation in linguists’ use of evaluation to perform scholarly identities in English academic writing. More specifically, it focuses on the use of statements, commands, modality, comment assessment, and positive and negative lexis, in early and late career papers from 30 linguists born between 1905 and 1960. These linguists were grouped into three cohorts based on year of birth and studied in terms of variation along developmental and cross-generational timescales. Within the developmental timescale, scholars were found to use more evaluation in early career writing than in late career writing. Cohort-specific developmental changes are identified in the frequency of modality and comment assessment. Developmental and cohort-specific trends are found to occur within the backdrop of an overall decrease in the use of evaluative language within the discipline. Results point to a complex diachronic model of academic identity enactment in writing, whereby evaluative features pattern in similar or different ways depending on the timescale considered.

Hydraulic Hybrid Cut-to-Length Forest Harvester—Evaluation of Effects on Productivity and Fuel Efficiency

A cut-to-length (CTL) forest harvester is a purpose-built, hydraulically actuated mobile work machine used for felling, delimbing, and cross-cutting trees into dimensions and assortments. In such a machine, the diesel engine load is known to fluctuate greatly over the work cycle. To manage these changing power demands, a hydraulic hybrid system is implemented into a full-scale proof-of-concept machine to discover its functionality and to collect experimental results in real operating conditions. The hydraulic hybrid system installed on a CTL harvester machine was tuned to enable the collection of two actual datasets of timber harvesting, and data collection over a period of production use was carried out. In addition to updating the state-of-the-art research into heavy non-road mobile machinery regarding hybrid systems, this paper discusses the two tests carried out in actual production conditions with the studied hydraulic hybrid system. The adaptations and modifications to the studied and tested system since earlier papers are discussed—especially the improvements in the system dynamics and response as well as the control of the hybrid system. In conclusion, the tested system can be said to operate satisfactorily and shows clear advantages over the conventional system, even though it still has some limitations. The results show that the system has the potential to increase the productivity of the machine through the demonstrated higher peak power, as well as showing improvement in fuel efficiency under highly fluctuating loads, especially with heavy or large-volume tree stems.

A blueprint most wonderful, the homeobox discovery.

This is a personal, non-linear summary of the discovery of the homeobox, a short DNA sequence encoding a DNA-binding domain conserved in developmental control genes. It is based on our recollections, a few decaying lab notebooks and letters, the early research papers we published, and conversations with a few colleagues who were in Basel at the time. It presents a simple story, when the research we did was anything but, with failed experiments, blind alleys and dumb ideas. Homeobox DNA sequences were independently discovered by Matt Scott and Amy Weiner in Thomas Kaufmann's lab at Indiana University ( Scott and Weiner, 1984). The accompanying Perspective from Scott (2024), provides their fascinating story.

The Largest Crossing Number of Tanglegrams

A tanglegram $\mathcal{T}$ consists of two rooted binary trees with the same number of leaves, and a perfect matching between the two leaf sets. In a layout, the tanglegrams is drawn with the leaves on two parallel lines, the trees on either side of the strip created by these lines are drawn as plane trees, and the perfect matching is drawn in straight line segments inside the strip. The tanglegram crossing number ${\rm cr}({\mathcal{T}})$ of $\mathcal{T}$ is the smallest number of crossings of pairs of matching edges, over all possible layouts of $\mathcal{T}$. The size of the tanglegram is the number of matching edges, say $n$. An earlier paper showed that the maximum of the tanglegram crossing number of size $n$ tanglegrams is $<\frac{1}{2}\binom{n}{2}$; but is at least $\frac{1}{2}\binom{n}{2}-\frac{n^{3/2}-n}{2}$ for infinitely many $n$. Now we make better bounds: the maximum crossing number of a size $n$ tanglegram is at most $\frac{1}{2}\binom{n}{2}-\frac{n}{4}$, but for infinitely many $n$, at least $\frac{1}{2}\binom{n}{2}-\frac{n\log_2 n}{4}$. The problem shows analogy with the Unbalancing Lights Problem of Gale and Berlekamp.

Density of smooth functions in Musielak–Orlicz–Sobolev spaces Wk,Φ(Ω)$W^{k,\Phi }(\Omega)$

AbstractWe consider here Musielak–Orlicz–Sobolev (MOS) spaces , where is an open subset of , and is a Musielak–Orlicz function. The main outcomes consist of the results on density of the space of compactly supported smooth functions in . One section is devoted to compare the various conditions on appearing in the literature in the context of maximal operator and density theorems in MOS spaces. The assumptions on we apply here are substantially weaker than in the earlier papers on the topics of approximation by smooth functions. One of the reasons is that in the process of proving density theorems, we do not use the fact that the Hardy–Littlewood maximal operator on Musielak–Orlicz space is bounded, a standard tool employed in density results for different types of Sobolev spaces. We show in particular that under some regularity assumptions on , (A1) and that are not sufficient for the maximal operator to be bounded, the space of is dense in . In the case of variable exponent Sobolev space , we obtain the similar density result under the assumption that , , , , satisfies the log‐Hölder condition and the exponent function is essentially bounded.

Controlling the polarization structure of vector beams synthesized by a fiber laser array

In our earlier paper [Adamov, E. V., Aksenov, V. P., Dudorov, V. V., Kolosov, V. V., & Levitskii, M. E. (2022). Controlling the spatial structure of vector beams synthesized by a fiber laser array. Optics & Laser Technology, 154, 108,351], we presented the method to control the spatial intensity distribution of a beam synthesized as a result of coherent combining of subbeams from an array of phase-controlled fiber radiation sources, each subbeam characterized by its own direction of linear polarization. In this paper, we consider theoretically and experimentally the feasibility of controlling the polarization structure of such synthesized beams by changing the phase relations between individual subbeams. It is shown that for fixed polarization directions of the subbeams, the nonuniform polarization distribution of the synthesized beam, whose character depends on the phase relations and polarization directions of the subbeams, can be controlled via a change of only subbeam phases.

Whittle index approach to multiserver scheduling with impatient customers and DHR service times

AbstractWe consider the optimal scheduling problem in a multiserver queue with impatient customers belonging to multiple classes. We assume that each customer has a random abandonment time, after which the customer leaves the system if its service has not been completed before that. In addition, we assume that the scheduler is not able to anticipate the expiration of the abandonment times but only knows their distributions and how long each customer has been in the system. Many papers consider this scheduling problem under Poisson arrivals and linear holding costs assuming further that both the service times and the abandonment times have exponential distributions. Even with these additional assumptions, the exact solution is known only in very few special cases. To tackle this tricky problem, we apply the Whittle index approach. Unlike the earlier papers, which were restricted to exponential service times, we allow the service time distributions for which the hazard rate is decreasing. The Whittle index approach is applied to the discrete-time multiserver queueing problem with discounted costs. As our main theoretical result, we prove that the related relaxed optimization problem is indexable and derive the corresponding Whittle index explicitly. Based on this discrete-time result, we develop a reasonable heuristic for the original continuous-time multiserver scheduling problem. The performance of the resulting policy is evaluated in the M/G/M setup by numerical simulations, which demonstrate that it, indeed, gives better performance than the other policies included in the comparison.

Riffing on Feyerabend: Direct Observation, Paraconsistentist Logic, and a Research Immanent Account of the Rationaliy of Science

Feyerabend’s work, particularly his early papers contain important insights into the nature of science and scientific progress. I discuss his insights into the limits of empiricist foundationalism and positivism. I explain how the work of a number of philosophers has borne out Feyerabend’s claims in startling and interesting ways. Nevertheless, I criticise Feyerabend’s move from his attack on universal method to relativism. I point out that Feyerabend never confronted a well-developed research immanent view of the rationality of scientific change, which shows the limitations of the arguments in Against Method.

Singular matrices and pairwise-tangent circles

The idea of using the generalised inverse of a singular matrix A to solve the matrix equation Ax = b has been discussed in the earlier papers [1, 2, 3, 4] in the Gazette. Here we discuss three simple geometric questions which are of interest in their own right, and which illustrate the use of the generalised inverse of a matrix. The three questions are about polygons and circles in the Euclidean plane. We need not assume that a polygon is a simple closed curve, nor that it is convex: indeed, abstractly, a polygon is just a finite sequence (v1, …, vn) of its distinct, consecutive, vertices. It is convenient to let vn + 1 = v1 and (later) Cn + 1 = C1.

Local Well-Posedness of the Skew Mean Curvature Flow for Small Data in d≧2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d\\geqq 2$$\\end{document} Dimensions

The skew mean curvature flow is an evolution equation for d dimensional manifolds embedded in Rd+2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\mathbb {R}}^{d+2}$$\\end{document} (or more generally, in a Riemannian manifold). It can be viewed as a Schrödinger analogue of the mean curvature flow, or alternatively as a quasilinear version of the Schrödinger Map equation. In an earlier paper, the authors introduced a harmonic/Coulomb gauge formulation of the problem, and used it to prove small data local well-posedness in dimensions d≧4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d \\geqq 4$$\\end{document}. In this article, we prove small data local well-posedness in low-regularity Sobolev spaces for the skew mean curvature flow in dimension d≧2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$d\\geqq 2$$\\end{document}. This is achieved by introducing a new, heat gauge formulation of the equations, which turns out to be more robust in low dimensions.

TOPICS SURROUNDING THE COMBINATORIAL ANABELIAN GEOMETRY OF HYPERBOLIC CURVES IV: DISCRETENESS AND SECTIONS

Abstract Let $\Sigma $ be a nonempty subset of the set of prime numbers which is either equal to the entire set of prime numbers or of cardinality one. In the present paper, we continue our study of the pro- $\Sigma $ fundamental groups of hyperbolic curves and their associated configuration spaces over algebraically closed fields in which the primes of $\Sigma $ are invertible. The present paper focuses on the topic of comparison between the theory developed in earlier papers concerning pro- $\Sigma $ fundamental groups and various discrete versions of this theory. We begin by developing a theory concerning certain combinatorial analogues of the section conjecture and Grothendieck conjecture. This portion of the theory is purely combinatorial and essentially follows from a result concerning the existence of fixed points of actions of finite groups on finite graphs (satisfying certain conditions). We then examine various applications of this purely combinatorial theory to scheme theory. Next, we verify various results in the theory of discrete fundamental groups of hyperbolic topological surfaces to the effect that various properties of (discrete) subgroups of such groups hold if and only if analogous properties hold for the closures of these subgroups in the profinite completions of the discrete fundamental groups under consideration. These results make possible a fairly straightforward translation, into discrete versions, of pro- $\Sigma $ results obtained in previous papers by the authors. Finally, we discuss a construction that was considered previously by M. Boggi in the discrete case from the point of view of the present paper.

Same-Sex Marriage Recognition and Taxes: New Evidence about the Impact of Household Taxation

Abstract The U.S. income tax code encourages marriage for some and discourages marriage for others, but same-sex couples were only recently exposed to these incentives. We estimate marriage responses by exploiting variation in the recognition of same-sex marriages for tax purposes versus earlier papers leveraging smaller changes. Using the American Community Survey, which reports cohabitation and marriage, we estimate a significant though very small marriage elasticity, with further analysis suggesting a higher (though still small) elasticity for low-earning households and in response to federal taxes specifically. Our estimates imply that the 2018 tax reform will increase marriage among high-earning cohabiting couples.

Using easy coefficients conjecture for rotation symmetric Boolean functions

A Boolean function in n variables is rotation symmetric (RS) if it is invariant under powers of ρ(x1,…,xn)=(x2,…,xn,x1). An RS function is called monomial rotation symmetric (MRS) if it is generated by applying powers of ρ to a single monomial. Completing earlier research on special cases, the author showed in 2018 that for any RS function fn in n variables, the sequence of Hamming weights wt(fn) for all values of n satisfies a linear recurrence relation. It was also proved that the associated recursion polynomial could be explicitly calculated as the minimal polynomial of a rules matrix and an algorithm for computing the rules matrix was explained. Examples showed that the usual formula which gives the values of wt(fn)−2n−1 as a linear combination of powers of the irrational roots of the minimal polynomial has simple coefficients which are all 1/2 if the multiset made up of the roots of the characteristic polynomial of the rules matrix is used instead, no matter what the degree of the Boolean function is. The conjecture that this is always true is called the Easy Coefficients Conjecture (ECC). The special case of MRS quadratics was proved in an earlier paper. The present paper gives some ECC applications valid for any function for which the ECC is true, even though there is a proof only for the quadratic MRS case so far.

A Network Analysis of Lucas’ Early Papers in Firm Microeconomics

A Network Analysis of Lucas’ Early Papers in Firm Microeconomics