Regular Type Research Articles

Inversion of electromagnetic induction data using a novel wavelet-based and scale-dependent regularization term

SUMMARY The inversion of electromagnetic induction data to a conductivity profile is an ill-posed problem. Regularization improves the stability of the inversion and a smoothing constraint is typically used. However, the conductivity profiles are not always expected to be smooth. Here, we develop a new inversion scheme in which we transform the model to the wavelet space and impose a sparsity constraint. This sparsity constrained inversion scheme will minimize an objective function with a least-squares data misfit and a sparsity measure of the model in the wavelet domain. A model transform to the wavelet domain allows to investigate the temporal resolution (periodicities at different frequencies) and spatial resolution (location of the peaks) characteristics of the model, and penalizing small-scale coefficients effectively reduces the complexity of the model. The novel scale-dependent regularization term can be used to favour either blocky or smooth structures, as well as high-amplitude models in globally smooth structures in the inversion. Depending on the expected conductivity profile, a suitable wavelet basis function can be chosen. The scheme supports multiple types of regularization with the same algorithm and is thus flexible. Finally, we apply this new scheme on a frequency domain electromagnetic sounding data set, but the scheme could equally apply to any other 1-D geophysical method.

Approximated solution algorithms for Urysohn-type equations

Problems of remote sensing and gravity, magnetic, seismic, geological prospecting use systems of indirect data measurement, which can be modeled with non-linear Urysohn equations. The paper presents equations of Urysohn type and their operator analogues. A number of algorithms for their solution has been developed based on the availability of a priori information, asymptotic properties of integral operators, and specific features of a model. It has been formulated a theorem on constructing a solution of the original equation based on the neighboring one with an error estimate. Both the original and neighboring equations are taken as the regularized equations. The proposed approach allows for a variety of algorithms, depending on the type of regularization and iteration schemes, in particular, a modified version of the Levenberg-Marquardt algorithm. Additionally, the algorithm for searching characteristic points of a given function based on the asymptotics of an integral Urysohn operator is provided.

The lasso binary logistic regression method for selecting variables that affect the recovery of Covid-19 patients in China

The Lasso regression performs the least squares method with the l 1-constraint. This is a particular type of regularization which adds a penalty equal to the absolute value of the magnitude of coefficients that can result in sparse models with few coefficients in which some coefficients can become zero and be eliminated. Larger penalties result in coefficient values closer to zero, which is ideal for producing simpler models. In this study, the lasso method has been applied to select variables affecting the recovery of the Covid-19 patients. The data consisted of the number of patients treated in several hospitals or clinics in China, recovered patients, demographics, comorbidities, symptoms, and treatment. The performance of the lasso binary logistic regression was compared with the full model of logistic and the stepwise logistic regression. The results showed that the number of independent variables selected by the lasso method was larger than those selected by the stepwise method. It has also been showed that coefficient values of variables produced by the lasso method were smaller than those produced by the stepwise. The independent variables that affect the cure rate of covid-19 patients with the lasso are gender, comorbidities, diabetes, cardiovascular, cough, fatigue, diarrhea, platelet count and antibiotics.

Portfolio Selection with Regularization

We study the Markowitz mean-variance portfolio selection model under three types of regularizations: single-norm regularizations on individual stocks, mixed-norm regularizations on stock groups, and composite regularizations that combine the single-norm and mixed-norm regularizations. With mixed-norm regularizations incorporated, our model can accomplish group and stock selections simultaneously. Our empirical results using both US and global equity market data show that compared to the classical mean-variance portfolio, almost all regularized portfolios have better out-of-sample risk-adjusted performance measured by Sharpe ratio. In addition, stock selection and group screening accomplished by adding [Formula: see text] and [Formula: see text] regularizations respectively can lead to decreased volatility, turnover rate, and leverage ratio. Yet there are instances in which diversifying across different groups is more favorable, depending on the grouping methods. Moreover, we find a positive correlation between portfolio turnover and leverage. Heavily leveraged portfolios also have high turnover rates and thus high transaction costs.

A new microlocal analysis of hyperfunctions

In this work we study microlocal regularity of hyperfunctions defining in this context a class of generalized FBI transforms first introduced for distributions by Berhanu and Hounie. Using a microlocal decomposition of a hyperfunction and the generalized FBI transforms we were able to characterize the wave-front set of hyperfunctions according to several types of regularity. The microlocal decomposition allowed us to recover and generalize both classical and recent results and, in particular, we proved for differential operators with real-analytic coefficients that if the elliptic regularity theorem regarding any reasonable regularity holds for distributions, then it is automatically true for hyperfunctions.

On the diversity of multi-head attention

Multi-head attention is appealing for the ability to jointly attend to information from different representation subspaces at different positions. In this work, we propose two approaches to better exploit such diversity for multi-head attention, which are complementary to each other. First, we introduce a disagreement regularization to explicitly encourage the diversity among multiple attention heads. Specifically, we propose three types of disagreement regularization, which respectively encourage the subspace, the attended positions, and the output representation associated with each attention head to be different from other heads. Second, we propose to better capture the diverse information distributed in the extracted partial-representations with the routing-by-agreement algorithm. The routing algorithm iteratively updates the proportion of how much a part (i.e. the distinct information learned from a specific subspace) should be assigned to a whole (i.e. the final output representation), based on the agreement between parts and wholes. Experimental results on the machine translation, sentence encoding and logical inference tasks demonstrate the effectiveness and universality of the proposed approaches, which indicate the necessity of better exploiting the diversity for multi-head attention. While the two strategies individually boost performance, combining them together can further improve the model performance.

Learning from hole-transporting polymers in regular perovskite solar cells to construct efficient conjugated polyelectrolytes for inverted devices

• A polyelectrolyte was designed with the same main-chain of a reported polymer HTM. • HTM based on it showed an efficiency of 19.92% in an inverted solar cell. • More thiophene unit gave a superior hole-extraction and defect-passivation ability. Owing to its high wettability and the resulting compatibility with the future industrial device fabrication process, the conjugated polyelectrolyte (CPE) has becoming a promising hole-transporting material (HTM) in the inverted perovskite solar cell (iPSC); however, only a few highly efficient CPEs have been reported probably due to the limited pool of molecular designing strategies. Here we construct a CPE named DTB(Na) with the same main-chain of a polymer DTB(EH) that was previously employed as a dopant-free HTM in a highly efficient regular type PSC (rPSC) and with simple water/alcohol soluble side-chains. Compared with its analog bearing the only variation of less thiophene units in the main-chain, DTB(Na) shows stronger capacities of hole-extraction and defect-passivation, which should be ascribed to the more intensive exposure of thiophene functional unit to the perovskite layer. As a result, the DTB(Na) iPSC device presents enhanced values on all the photovoltaic parameters and long-term stability, and a power conversion efficiency of 19.92% is realized. Our results demonstrate the feasibility for efficient polymeric HTMs in rPSCs and iPSCs to share the same main-chains, thus enriching the molecular designing strategies and probably expanding the library of efficient HTMs for iPSCs.

Two problems about calculating the number of palindromes with different numbers of digits

The aim of this work is to obtain two types of regularities for calculating the number of palindromes. The main results of the work are presented by solving two problems. In the first problem describes how to find the total number of different locations of palindromes in binary digits that do not exceed the given numbers of digits. The second problem is devoted to determining the number of palindromes of an arbitrary number system that have the same numbers of digits. The theoretical results of the work are accompanied by examples of the application of the described regularities to obtain the total number of locations of the binary palindromes with the number of digits that do not exceed the specified, as well as to calculate the number of palindromes of different number systems with predetermined numbers of digits. The considered regularities are supposed to be applied in the analysis of numerical and computer data.

In-silico analysis of non-synonymous SNPs of human LDLR gene and their impact on familial hypercholesterolemia

Single nucleotide polymorphisms (SNPs) are the most regular type of genetic variation among human genome. The low-density lipoprotein receptors (LDLR) gene encoded receptor protein that specifically binds to low density lipoprotein (LDL), to act as prime cholesterol carriers in the blood. Unregulated removal of LDL from the circulation results from inherited mutations in the LDLR gene or, more rarely, in the apo B gene, the ligand for the LDLR causes familial hypercholesterolemia (FH). Several studies have shown that non-synonymous single nucleotide polymorphisms (nsSNPs) induce more than 50% genetic diseases. However, the growing number of SNPs in databases makes it difficult to evaluate the SNPs that come up with disease development. Therefore, we tried to identify the nsSNP within LDLR gene used mainly computational tools like: PROVEAN, Predict-SNP, SIFT, MAAP, SNAP, PhD-SNP, Polyphen v1, Polyphen v2, PANTHER and nsSNPAnalyzer. After analysing a total of 1114 missense SNPs, we found only 39 nsSNPs are most deleterious, whose conservation score ranges from grade ranges 7 to 9 that is assessed through ConSurf web server. Among 39 most significant nsSNPs, 11were predicted for involving in post translational modifications. Additionally, I-Mutant 2.0 and MUpro tool showed a decreased instability for these nsSNPs upon mutation. Protein structural analysis of these amino acid variants was performed by using I-Mutant 2.0. Stability analysis predicted 11 nsSNPs (C313W, F408K, A431P, A431S, A431T, D433H, D433Y, G546D, G546V, G546E and C697W), these are decreased protein stability. The in-silico analysis in current study may be a significant model for future research design studies.

Hysteresis and turbulent vortex breakdown in transitional swirling jets

Vortex breakdown (VB) in unconfined swirling jets occurs as either a bubble form of vortex breakdown (BVB) or a conical form of vortex breakdown (CVB). This computational study examines flow features of these forms for a Reynolds number at which VB is accompanied by a transition to turbulence ( $Re = 1000$ , based on inflow jet radius and centreline velocity). Large eddy simulations were performed with the inflow condition as the Maxworthy profile which models a laminar, axisymmetric swirling jet, and the effect of varying inflow swirl strength was investigated. BVB was observed at lower swirl strengths than those at which CVB occurs. With increasing swirl, the regular and wide-open types of CVB occur. Spiral coherent structures that develop in the flow were examined using spectral proper orthogonal decomposition. Further, by means of hysteresis studies, it is established that the turbulent BVB and regular CVB are bistable forms. Similarly, it is shown that the two types of CVB are also bistable. The difference in recirculation zone (RZ) sizes between the turbulent BVB and regular CVB is greatly reduced when compared to the laminar counterparts. This is postulated as a reason for misidentification of CVB (RZ approximately conical in shape) as BVB (spheroidal RZ) in some previous studies. The present study highlights the distinct features of turbulent BVB and CVB, which can potentially be used towards improving designs of swirl-stabilized combustors.

A theoretical and experimental case study of the hydrogen bonding predilection of S-methylcysteine

S-containing amino acids can lead to two types of local NH···S interactions which bridge backbone NH sites to the side chain to form either intra- or inter-residue H-bonds. The present work reports on the conformational preferences of S-methyl-L-cysteine, Cys(Me), using a variety of investigating tools, ranging from quantum chemistry simulations, gas-phase UV and IR laser spectroscopy, and solution state IR and NMR spectroscopies, on model compounds comprising one or two Cys(Me) residues. We demonstrate that in gas phase and in low polarity solution, the C- and N-capped model compound for one Cys(Me) residue adopts a preferred C5-C6γ conformation which combines an intra-residue N-H···O=C backbone interaction (C5) and an inter-residue N-H···S interaction implicating the side-chain sulfur atom (C6γ). In contrast, the dominant conformation of the C- and N-capped model compound featuring two consecutive Cys(Me) residues is a regular type I β-turn. This structure is incompatible with concomitant C6γ interactions, which are no longer in evidence. Instead, C5γ interactions occur, that are fully consistent with the turn geometry and additionally stabilize the structure. Comparison with the thietane amino acid Attc, which exhibits a rigid cyclic side chain, pinpoints the significance of side chain flexibility for the specific conformational behavior of Cys(Me).

The nomological argument for the existence of God

AbstractAccording to the Nomological Argument, observed regularities in nature are best explained by an appeal to a supernatural being. A successful explanation must avoid two perils. Some explanations provide too little structure, predicting a universe without regularities. Others provide too much structure, thereby precluding an explanation of certain types of lawlike regularities featured in modern scientific theories. We argue that an explanation based in the creative, intentional action of a supernatural being avoids these two perils whereas leading competitors do not. Although our argument falls short of a full defense, it does suggest that the Nomological Argument is worthy of philosophical attention.

Numerical schemes for the time-fractional mobile/immobile transport equation based on convolution quadrature

In this work, the numerical approximation of the time-fractional mobile/immobile transport equation is considered. We investigate the solution regularity for two types of the initial data regularities. By applying the continuous piecewise linear finite elements in space, we obtain the spatial semidiscrete Galerkin scheme and derive its error estimates. We then propose two finite element schemes for the equation by employing convolution quadrature based on the backward Euler and the second-order backward difference methods. The corresponding error estimates for the two schemes are also given. Numerical examples of the two-dimensional problems are shown to confirm the convergence theory results.

Right lateralized alpha desynchronization increases with the proportion of symmetry in the stimulus.

Research into the neural basis of symmetry perception has intensified in the last two decades; however, the functional role of neural oscillations remains unclear. In previous work Makin et al. (2014, Journal of Vision, 14, 1-12) and Wright et al. (2015, Psychophysiology, 52, 638-647) examined occipital alpha event-related desynchronization (alpha ERD). It was concluded that alpha ERD is right lateralized during active regularity discrimination but not during a secondary task. Furthermore, alpha ERD was unaffected by stimulus properties, such as the type of regularity. These conclusions are refuted by new time-frequency analysis on an electroencephalography (EEG) data set first introduced by Makin et al. (2020, Journal of Cognitive Neuroscience, 32, 353-366). We compared alpha ERD across five tasks. First, we found that right lateralization of alpha ERD was evident in all tasks, not just active regularity discrimination. This was caused by hemispheric differences in alpha power during prestimulus baseline (left<right), which equalized after stimulus onset (left=right). Second, we found that Alpha ERD increased with the proportion of symmetric elements in the image (PSYMM). Sensitivity to PSYMM was stronger on the right. These findings suggest that known extrastriate symmetry activations are accompanied by reduced alpha power.

Radiological evaluation of maxillofacial soft tissue calcifications with cone beam computed tomography and panoramic radiography

We aimed to present the radiologic characteristics of maxillofacial soft tissue calcifications with a comparison of cone beam computed tomography (CBCT) and panoramic radiography (PR) findings. The study was based on CBCT images obtained for different purposes between October 2017 and September 2018. The absence, location and radiological characteristics of some calcifications were evaluated in 252 patients. Statistical analysis was performed with SPSS version 21.0; p < 0.05 was considered to indicate statistical significance. Palatine tonsilloliths were the most common calcifications in our study. Calcifications were most frequent in the sixth decade of life. Females had larger calcifications than males. There was a relationship between the sizes measured by CBCT and PR for tonsilloliths. In PR, region 2 had significantly more calcifications compared with the other regions. The C2 vertebral level was the most common region for tonsilloliths based on CBCT. Tonsilloliths have a high prevalence. The regular peripheral type had a higher risk of being a tonsillolith in PR. The peripheral/internal characteristics and the dimensions of calcifications between the two imaging modalities were in harmony. The location of calcification in PR and CBCT was important to distinguish the type of calcification.

Мероприятия циклового типа как перспективное направление деятельности литературного музея

A long-term, mutually interesting relationship with the public is the goal of most of the world’s museums. The author of the article suggests that a promising form of organizing museum events are programs of a regular type, formed into thematic cycles. The study explains both theoretical grounds and practical arguments emphasizing the relevance of the application of this form of events in the practice of museums. The study was based on the experience of The National Pushkin Museum, which demonstrated the possibility of multifaceted coverage of a given topic within thematic cycles, synthesizing in one event different forms of impact on the visitor. Review of cycle-type programs of two other museums – The Pushkin Museum and The State Literature Museum, confirms the conclusions that this form of organizing events contributes to the development of the cultural and educational aspect of museum activities, an increase in the number of regular visitors, an increase in the professional motivation of museum staff, and forms a favorable image of the museum, increasing its competitiveness. The prospect of cyclical events is reflected in modern trends in society towards self-education.

The Association between Regular Physical Activity Types And Metabolic Syndrome in Fertile Women

The Association between Regular Physical Activity Types And Metabolic Syndrome in Fertile Women

Structural Analysis of Chassis using AISI 4130 and AA 7068

The chassis frame is the backbone of a vehicle to safely carry the maximum load for all the designed operating conditions. This paper describes the design and analysis of vehicle chassis using different materials for different cross sections. The main objective of this attempt is to reduce the self-weight of the chassis. In this work a truck chassis is taken for modeling and analysis. Two different alloy materials of steel and aluminium are considered for three different cross sections namely I, C and regular box type. SOLIDWORKS and ANSYS software are used for modeling and analysis of this work respectively.

Regularized potentials of Schrödinger operators and a local landscape function

We study localization properties of low-lying eigenfunctions for rapidly varying potentials V in bounded domains Filoche & Mayboroda introduced the landscape function and showed that the function u has remarkable properties: localized eigenfunctions prefer to localize in the local maxima of u. Arnold, David, Filoche, Jerison & Mayboroda showed that arises naturally as the potential in a related equation. Motivated by these questions, we introduce a one-parameter family of regularized potentials Vt that arise from convolving V with the radial kernel We prove that for eigenfunctions this regularization Vt is, in a precise sense, the canonical effective potential on small scales. The landscape function u respects the same type of regularization. This allows allows us to derive landscape-type functions out of solutions of the equation for a general right-hand side

Pions and Contacts at N4LO: Some details on the chiral nuclear force

In this work we have performed a detailed study of chiral nuclear forces at N4LO approximation applied to selected channels of the neutron–proton (np) scattering. The idea is to analyse the different contributions to the nucleon–nucleon (NN) potential by separating the part coming from the exchange of pions and the one coming from the contact interactions. We consider two state-of-the-art chiral interactions at N4LO which are constructed using different regularization procedures: the non-local Idaho–Salamanca force and the semi-local interaction from the Bochum group. In order to compare the two types of regularization we consider both interactions with a 500 MeV cutoff and to analyse the cutoff dependence we select the Bochum potential with three different cutoff values: 500, 450 and 400 MeV. Our results show that the balance between pion exchanges and contact interactions depends strongly on the regularization procedure. The non-local angle-independent regularization of both components of the interaction implemented in the Idaho–Salamanca potential makes the contact terms to be present at large distances while the local regularization of the pion exchanges in the Bochum potential restricts the contact interactions to small distances. Also, the value of the cutoff affects the strength of the potential but the interplay between pion exchanges and contact terms remains qualitatively the same.