Sequential Space Research Articles

Cardinal inequalities involving the weak Rothberger and cellularity games

We prove several results in the theory of topological cardinal invariants involving the game-theoretic versions of the weak Lindelöf degree and of cellularity. One of them is related to Bell, Ginsburg and Woods’s 1978 question of whether every weakly Lindelöf regular first-countable space has cardinality at most continuum and another one is connected with Arhangel’skii’s 1970 question on the weak Lindelöf degree of the Gδ\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$G_\\delta $$\\end{document} topology on a compact space. We provide a few application of our results, including some bounds on the cardinality of sequential and radial spaces. We finish with a series of counterexamples, which show the sharpness of our results and disprove a few natural conjectures about the impact of infinite games on topological cardinal invariants.

Structure of the basement of the near-Laptev part of the Eurasian basin according to geological and geophysical data

The near-Laptev part of the Eurasian basin is the area of transition from modern spreading to intraplate rifting. We propose an approach to the construction of a 3D model of the basement of the Laptev Sea part of the Eurasian basin based on the linkage of all currently available geological and geophysical data. The structure of the acoustic basement of the Eurasian basin is characterized by alternating troughs and highs in cross-section. The sparse seismic data do not allow us to directly trace the strike of these structures, but they can be correlated with the linearity established by gravity and magnetic data and related to the sequential opening of the basin. For the Laptev Sea part of the Eurasian basin, where linearity is no longer traceable from magnetic data, we propose a method of determining the strike of the basement structures on the basis of seismic stratigraphic analysis. The new 3D model of the acoustic basement in the studied area provided the basis for the tectonic scheme of the entire Eurasian basin. The model reflects the main stages of basin development: continental rifting up to 56 Ma, normal spreading 56–45 Ma, ultra-slow spreading 45–34 Ma, ultra-ultra-slow spreading 34–20 Ma. The southern part of the study area is overlain by a sedimentary cover with an age of 20 Ma and younger, which is associated with the cessation of spreading here no later than 20 Ma.

High‐Performance Cooperative DNA Nanodevice Enables Sensitive Circular RNA Imaging and Precise Tumor Growth Suppression

The utility of circular RNAs (circRNAs) as emerging biomarkers and regulatory factors in medical diagnostics and therapeutics is hampered by the challenges associated with their sensitive detection and precise modulation. Herein, a high‐performance cooperative DNA nanodevice (HCDN) based on DNA tetrahedron‐confined catalytic DNA assembly reaction (DT‐CDA) that enables both imaging and regulation of circRNAs is developed. Activation of the DT‐CDA is contingent upon the presence of the target circRNA, which, together with a replicative fuel probe, catalyzes the sequential opening of additional DT‐CDAs. This cooperative exponential signal amplification with negligible background interference allows HCDN to effectively detect minute quantities of circRNAs. Employing circSATB2 as a model, the HCDN demonstrates substantial downregulation of Cyclin D1 (CCND1) mRNA and protein levels in cellular and in vivo models, thereby inhibiting tumor growth. The innovative design of HCDN sets the stage for a powerful methodology conducive to enhanced clinical diagnostics and biomolecule manipulation, thereby advancing the capabilities and applications of DNA nanotechnology.

Solving Fractional Boundary Value Problems with Nonlocal Mixed Boundary Conditions Using Covariant JS-Contractions

This paper investigates the existence, uniqueness, and symmetry of solutions for Φ–Atangana–Baleanu fractional differential equations of order μ∈(1,2] under mixed nonlocal boundary conditions. This is achieved through the use of covariant and contravariant JS-contractions within a generalized framework of a sequential extended bipolar parametric metric space. As a consequence, we obtain the results on covariant and contravariant Ćirić, Chatterjea, Kannan, and Reich contractions as corollaries. Additionally, we substantiate our fixed-point findings with specific examples and derive similar results in the setting of sequential extended fuzzy bipolar metric space.

Addressing equifinality in agent-based modeling: a sequential parameter space search method based on sensitivity analysis

This study addresses the challenge of equifinality in agent-based modeling (ABM) by introducing a novel sequential calibration approach. Equifinality arises when multiple models equally fit observed data, risking the selection of an inaccurate model. In the context of ABM, such a situation might arise due to limitations in data, such as aggregating observations into coarse spatial units. It can lead to situations where successfully calibrated model parameters may still result in reliability issues due to uncertainties in accurately calibrating the inner mechanisms. To tackle this, we propose a method that sequentially calibrates model parameters using diverse outcomes from multiple datasets. The method aims to identify optimal parameter combinations while mitigating computational intensity. We validate our approach through indoor pedestrian movement simulation, utilizing three distinct outcomes: (1) the count of grid cells crossed by individuals, (2) the number of people in each grid cell over time (fine grid) and (3) the number of people in each grid cell over time (coarse grid). As a result, the optimal calibrated parameter combinations were selected based on high test accuracy to avoid overfitting. This method addresses equifinality while reducing computational intensity of parameter calibration for spatially explicit models, as well as ABM in general.

Rapid Synthesis of 3-Methyleneisoindolin-1-ones via Metal-Free Tandem Reactions of Ester-Functionalized Aziridines.

We have disclosed a novel metal-free tandem cyclization reaction for the synthesis of 3-methyleneisoindolin-1-ones starting from ester-functionalized aziridines. This strategy can be effectively promoted by DBU and carboxylic acids. Mechanistically, it involves sequential ring opening of aziridines with carboxylic acids, lactamization, and elimination of carboxylic acids.

BUCKLING CURVE CALIBRATION FOR STEEL I‐BEAMS WITH SEQUENTIAL WEB OPENINGS CONSIDERING RANDOM INITIAL IMPERFECTIONS

AbstractSteel beams with sequential web openings present benefits compared to plain webbed sections, especially higher bending stiffness. However, openings can affect structural behavior, requiring modifications to verification methods. In this study, a new proposal was developed to verify steel profiles with sequential web openings, based on Eurocode 3. The calculation leads to the determination of the reduction in the resistant capacity of the section due to instabilities based on an imperfection factor related to the characteristic process of manufacturing these profiles. For this, an extensive numerical study was carried out, considering random distributions of residual stresses based on experimental data.

\(\mathcal{I}^{\mathcal{K}}\)-SEQUENTIAL TOPOLOGY

In the literature, \(\mathcal{I}\)-convergence (or convergence in \(\mathcal{I}\)) was first introduced in [11]. Later related notions of \(\mathcal{I}\)-sequential topological space and \(\mathcal{I}^*\)-sequential topological space were introduced and studied. From the definitions it is clear that \(\mathcal{I}^*\)-sequential topological space is larger(finer) than \(\mathcal{I}\)-sequential topological space. This rises a question: is there any topology (different from discrete topology) on the topological space \(\mathcal{X}\) which is finer than \(\mathcal{I}^*\)-topological space? In this paper, we tried to find the answer to the question. We define \(\mathcal{I}^{\mathcal{K}}\)-sequential topology for any ideals \(\mathcal{I}\), \(\mathcal{K}\) and study main properties of it. First of all, some fundamental results about \(\mathcal{I}^{\mathcal{K}}\)-convergence of a sequence in a topological space \((\mathcal{X} ,\mathcal{T})\) are derived. After that, \(\mathcal{I}^{\mathcal{K}}\)-continuity and the subspace of the \(\mathcal{I}^{\mathcal{K}}\)-sequential topological space are investigated.

Методика вскрытия и извлечения органов лабораторных животных. Сообщение 7: собаки, кошки

Necropsy and subsequent histological examination of organs and tissues are one of the main methods of studying toxicity necessary for an adequate assessment of the results of preclinical studies. In view of this, there is a need to develop a certain order of necropsy, ensuring the repeatability of the manipulations performed from stage to stage and from experiment to experiment, as well as allowing organs to be extracted in the required composition, preserving their integrity suitable for histological examination, and optimally using working time. The purpose of this work is to describe methodology for necropsy and extracting organs of dogs (using the example of the beagle breed) and cats, applicable in preclinical studies. Dogs are used to evaluate the pharmacological safety, pharmacokinetics and efficacy of tested drugs. They also serve as a model for studying epilepsy, osteoarthritis and other pathologies. Cats are used in the study of some infectious, ophthalmological diseases and for conducting a number of studies to evaluate the pharmacokinetic parameters of the drug being tested. Both types of animals are susceptible to spontaneous diseases and are used in cardiological research, in the study of metabolic diseases (in particular, diabetes), in comparative oncology. Animals are used as a model of inflammatory diseases, in biomedical research (as sources of stem cells). The article describes the methodology step by step from the procedure of preparation for necropsy, external examination, to the sequential opening of cavities and body parts for the extraction of organs. All methods of organ extraction, as well as the sequence of actions described in this article, ensure the reproducibility of the stages of necropsy, the extraction of organs in the required composition while maintaining their integrity suitable for further histological examination, minimizing their damage, optimizing the workflow.

On-Surface Synthesis of Multiple Cu Atom-Bridged Organometallic Oligomers.

A metal-metal bond between coordination complexes has the nature of a covalent bond in hydrocarbons. While bimetallic and trimetallic compounds usually have three-dimensional structures in solution, the high directionality and robustness of the bond can be applied for on-surface syntheses. Here, we present a systematic formation of complex organometallic oligomers on Cu(111) through sequential ring opening of 11,11,12,12-tetraphenyl-1,4,5,8-tetraazaanthraquinodimethane and bonding of phenanthroline derivatives by multiple Cu atoms. A detailed characterization with a combination of scanning tunneling microscopy and density functional theory calculations revealed the role of the Cu adatoms in both enantiomers of the chiral oligomers. Furthermore, we found sufficient strength of the bonds against sliding friction by manipulating the oligomers up to a hexamer. This finding may help to increase the variety of organometallic nanostructures on surfaces.

Drivers of Foreign Direct Investment Inflows to Emerging Asian Economies

This article examines the role of domestic and global factors in driving foreign direct investment (FDI) inflows to Asian emerging economies. Conventional panel estimations do not adequately account for the interdependence among countries caused by common global shocks and spatial effects. This article, employing a novel technique, augments the panel cointegration estimations with a proxy for unobserved common factors extracted from the augmented mean group regression. Our estimations control for nonstationarity, endogeneity, cross-sectional dependence, and heterogeneity. Based on the data of six Asian emerging economies from 2000Q1 to 2019Q4, we find a significant impact of both push (global) and pull (domestic) factors in attracting FDI. Our policy implication suggests the sequential opening of the capital account with capital controls and macroprudential regulations in place. JEL Codes: F21, F30, F41

Nonlinear Inelastic Stability Behavior of High-Strength Stainless Steel I-Beams with Sinusoidal Web Openings

Perforated beams can bring countless benefits compared to traditional plain-webbed beams. However, steel beams with sequential web openings are more susceptible to instabilities, and special care must be taken in a design concerning the failure modes these structures can present. The study presented herein explicitly dealt with the stability behavior of perforated beams with sinusoidal openings. This type of perforated member features smooth-lined openings constructed from a single thermal cut in conventional plain-webbed steel profiles. A broad study was carried out through numerical simulation using the ABAQUS software, in which perforated profiles manufactured with S600E high-strength stainless steel were studied. The use of high-strength steels in perforated profiles is a little explored topic in the literature, despite having a significant impact on the behavior of these elements. With the study carried out, a broad overview of the stability behavior of these members was obtained, especially concerning global stability. A total of 5940 FE models were developed, considering the application of different types of loads. In these models, linear buckling analysis (LBA) and geometrically and materially nonlinear analysis with imperfections (GMNIA) were performed. The results obtained were compared with international design codes, and it was found that some codes fail to represent the behavior of members that present lateral-distortional buckling (LDB) and interactions between local and global failure modes. This behavior is a significant design concern since the studied members had high yield strength, making them more susceptible to interaction-governed failure modes than usual-yield strength members. Additionally, the study found that some design codes do not accurately represent the behavior of members loaded outside the shear center due to the destabilizing effect of loading on these structures.

Diverse Image Captioning via Conditional Variational Autoencoder and Dual Contrastive Learning

Diverse image captioning has achieved substantial progress in recent years. However, the discriminability of generative models and the limitation of cross entropy loss are generally overlooked in the traditional diverse image captioning models, which seriously hurts both the diversity and accuracy of image captioning. In this paper, aiming to improve diversity and accuracy simultaneously, we propose a novel Conditional Variational Autoencoder (DCL-CVAE) framework for diverse image captioning by seamlessly integrating sequential variational autoencoder with contrastive learning. In the encoding stage, we first build conditional variational autoencoders to separately learn the sequential latent spaces for a pair of captions. Then, we introduce contrastive learning in the sequential latent spaces to enhance the discriminability of latent representations for both image-caption pairs and mismatched pairs. In the decoding stage, we leverage the captions sampled from the pre-trained Long Short-Term Memory (LSTM), LSTM decoder as the negative examples and perform contrastive learning with the greedily sampled positive examples, which can restrain the generation of common words and phrases induced by the cross entropy loss. By virtue of dual constrastive learning, DCL-CVAE is capable of encouraging the discriminability and facilitating the diversity, while promoting the accuracy of the generated captions. Extensive experiments are conducted on the challenging MSCOCO dataset, showing that our proposed methods can achieve a better balance between accuracy and diversity compared to the state-of-the-art diverse image captioning models.

Sequential closure of the abdominal wall for the management of open abdomen. A new surgical technique

Sequential closure of the abdominal wall for the management of open abdomen. A new surgical technique

A Simple and Fast Heuristic Approach for the Reconfiguration of Radial Distribution Networks

This letter proposes a two-stage heuristic approach to reconfigure a radial distribution network in the least possible computational time. All the network switches are closed in the initial stage of the operation, and a sequential switch opening strategy is suggested to obtain a near-optimal radial configuration. In the subsequent stage, a pair of switches is selected from the radial network to exchange its ON/OFF status. A mathematical model, using bus injection to branch current matrix, is developed to choose a pair of switches with an objective to reduce the power loss in the network after each exchange operation. The proposed approach is tested on 33-bus, 69-bus, 84-bus, 136-bus, and 417-bus distribution networks, and the results confirm that the suggested methodology helps in achieving the best configuration of the radial distribution networks in a significantly low run-time.

Chiral Indolizinium Salts Derived from 2-Pyridinecarbaldehyde-First Diastereoselective Syntheses of (-)-1-epi-lentiginosine.

The first diastereoselective synthesis of (-)-1-epi-lentiginosine from a common chiral trans-epoxyamide derived from 2-pyridincarbaldehyde is reported. This methodology involves a sequential oxirane ring opening and intramolecular 5-exo-tet cyclization of tosylate trans-epoxyalcohol to afford a diastereomeric mixture of indolizinium salts in a one-pot fashion, followed by regio- and diastereospecific pyridinium ring reduction.

Unzipping supercontinent Pangea: Geologic, potential field data, and buried structures, and a case for sequential Atlantic opening

Amalgamation of Pangea culminated with zippered N-to-S closing of the Theic ocean during the Alleghanian orogeny. Transpressional-rotational collision produced widespread dextral faulting throughout the eastern Appalachian hinterland, and thrust faulting in the western hinterland and foreland. The partially buried southern Appalachian Eastern Piedmont fault system is a product of late Paleozoic transpressional dextral faulting. Eastern Piedmont fault system faults are cut by two 200–190 Ma Central Atlantic Magmatic Province (CAMP) diabase dike sets (∼NW and NS), which postdate initial rifting, producing the Late Triassic-Early Jurassic basins. Sinistral reactivation of suitably oriented Paleozoic faults (e.g., Towaliga) that offset Jurassic dikes implies faulting is coeval with CAMP dike emplacement, or occurred very soon after 200–190 Ma dike emplacement. A large NE-striking sinistral fault (Estill fault) offsets magnetic and gravity highs in the Brunswick (Charleston) terrane in South Carolina and Georgia. This fault is at least 185 km long, with ca. 75–80 km maximum of sinistral separation. The Estill fault geometry agrees with the stress field associated with Central Atlantic Magmatic Province dike emplacement. We conclude that movement along the Estill and other sinistral faults represents Early Jurassic displacement that is well documented in eastern North America prior to Atlantic opening. The early Mesozoic post-failed rifting (basin formation) preceded dike emplacement and pre-spreading sinistral faulting. We recognize four stages in the Late Triassic–Jurassic tectonics and kinematics of eastern North America based on field, crosscutting relationships, and available geophysical data: (1) initial W-to-E failed transtensional rifting with formation of the S-to-N-younging Triassic-Jurassic basins; (2) CAMP diabase dikes intruded 200–190 Ma; (3) sinistral movement of large blocks of crust in the North Atlantic region including southeastern North America; and (4) spreading and opening of the Atlantic Ocean 195–170 Ma. These stages mark the reversal of Alleghanian rotational dextral transpressional (zippered) collision forming Pangea supercontinent and ‘unzipping’ the supercontinent prior to Atlantic opening.

Comparative analysis of fire-adapted models for the shear buckling strength of web-posts in castellated steel beams

Web-post buckling by shear is one of the typical failure modes of beams with sequential web openings, as well as the preponderant failure mode in fire. With the increase of the temperature, the modulus of elasticity of steel reduces faster than its resistance, so the beam becomes more susceptible to failure due to instability. This paper presents a comparison between existing formulations for determining the shear buckling strength of web-posts and validated numerical results. The objective was to assess if they are valid in fire conditions, with the modification of the modulus of elasticity and yield strength of steel according to each temperature considered in the analysis, using the statistical evaluation method present in EN 1990:2002. It was evident that the formulations analyzed are satisfactory at ambient temperature but most of them need adjustments when applied in fire.

Concrete functors that respect initiality and finality

We study concrete endofunctors of the category of convergence spaces and continuous maps that send initial maps to initial maps or final maps to final maps. The former phenomenon turns out to be fairly common while the latter is rare. In particular, it is shown that the pretopological modification is the coarsest hereditary modifier finer than the topological modifier and this is applied to give a structural interpretation of the role of Fréchet-Urysohn spaces with respect to sequential spaces and of k' -spaces with respect to k -spaces.

The minimum principle on the sequential complete local convex spaces

The minimum principle on the sequential complete local convex spaces