Miracle-dz/UniFAR-FTUs huggingface dataset:
Generalized Stability Theory. Part II: Nonautonomous Operators

Abstract An extension of classical stability theory to address the stability of perturbations to time-dependent systems is described. Nonnormality is found to play a central role in determining the stability of systems governed by nonautonomous operators associated with time-dependent systems. This pivotal role of nonnormality provides a conceptual bridge by which the generalized stability theory developed for analysis of autonomous operators can be extended naturally to nonautonomous operators. It has been shown that nonnormality leads to transient growth in autonomous systems, and this result can be extended to show further that time-dependent nonnormality of nonautonomous operators is capable of sustaining this transient growth leading to asymptotic instability. This general destabilizing effect associated with the time dependence of the operator is explored by analysing parametric instability in periodic and aperiodic time-dependent operators. Simple dynamical systems are used as examples including th.
Visualizing output for a data learning algorithm

This paper details the process we went through to visualize the output for our data learning algorithm. We have been developing a hierarchical self-structuring learning algorithm based around the general principles of the LaRue model. One example of a proposed application of this algorithm would be traffic analysis, chosen because it is conceptually easy to follow and there is a significant amount of already existing data and related research material with which to work with. While we choose the tracking of vehicles for our initial approach, it is by no means the only target of our algorithm. Flexibility is the end goal, however, we still need somewhere to start. To that end, this paper details our creation of the visualization GUI for our algorithm, the features we included and the initial results we obtained from our algorithm running a few of the traffic based scenarios we designed.
The Alfven-Falthammar formula for the parallel E-field and its analogue in downward auroral-current regions

The authors give an alternative derivation of the Alfven-Falthammar formula for a positive parallel E-field in upward auroral-current regions and its analogue for a negative parallel E-field in downward auroral-current regions. These formulas give new insight into the physics of the Birkeland current system. They find that for downward auroral-current regions, the velocity-space anisotropy in the ion distribution function is such that half the ion energy perpendicular to the magnetic field is greater than the ion energy parallel to the magnetic field. This is just opposite to the case for upward auroral-current regions. These results are compared to recent particle-in cell simulations and FREJA satellite data.
Acoustic Emission Generated in Corners of Reinforced Concrete Rigid Frame Under Cyclic Loading

A fundamental study was made of the acoustic emission (AE) behavior of reinforced concrete structures under cyclic loading. The growth of tensile cracks, shear cracks and bond failure of the reinforcement in an L shaped rigid frame of reinforced concrete was monitored by AE. The results were compared with visual observation and the measured value of crack widths and deflections. From the tests, it was shown that different AE sources could be clearly discriminated by comparing the AE parameter data with the results of visual observation and crack width measurement. It was revealed that the Kaiser effect exists so long as the width of tensile cracks is smaller than about 0.15--0.20 mm (0.006--0.0078 in.). However, it fails after the width has reached this value and with the onset of shear cracks. The Kaiser effect, thus, becomes a very effective method for estimating the level of deterioration in concrete structures. Moment tensor analysis, a quantitative AE waveform analysis based on the moment tensor modeling of cracks, was applied to classify crack types and to determine crack orientations in the fracture process of a rigid reinforced concrete frame. Crack orientations determined from eigenvectors obtained by decomposition of moment tensor components and crack more » directions presented as crack-opening vectors for tensile cracks and fault-motion vectors for shear cracks were in good agreement with the visual observation of the surface cracks. The moment tensor analysis showed that shear cracks start to appear and play a primary role when the Kaiser effect fails. « less
Velocity Distributions among Colliding Asteroids

Abstract The probability distribution for impact velocities between two given asteroids is wide, non-Gaussian, and often contains spikes according to our new method of analysis in which each possible orbital geometry for collision is weighted according to its probability. An average value would give a good representation only if the distribution were smooth and narrow. Therefore, the complete velocity distribution we obtain for various asteroid populations differs significantly from published histograms of average velocities. For all pairs among the 682 asteroids in the main-belt with D > 50 km, we find that our computed velocity distribution is much wider than previously computed histograms of average velocities. In this case, the most probable impact velocity is ∼4.4 km/sec, compared with the mean impact velocity of 5.3 km/sec. For cases of a single asteroid (e.g., Gaspra or Ida) relative to an impacting population, the distribution we find yields lower velocities than previously reported by others. The width of these velocity distributions implies that mean impact velocities must be used with caution when calculating asteroid collisional lifetimes or crater-size distributions. Since the most probable impact velocities are lower than the mean, disruption events may occur less frequently than previously estimated. However, this disruption rate may be balanced somewhat by an apparent increase in the frequency of high-velocity impacts between asteroids. These results have implications for issues such as asteroidal disruption rates, the amount/type of impact ejecta available for meteoritical delivery to the Earth, and the geology and evolution of specific asteroids like Gaspra.
Regulatory Mechanisms and Reversal of CD8+T Cell Exhaustion: A Literature Review

Simple Summary It has been known for decades that immune T cells, especially due to their capacity for powerful antigen-directed cytotoxicity, have become a central focus for engaging the immune system in the fight against cancer. Interest in harnessing T cells for cancer immunotherapy is rapidly growing. The latest clinical research aims to effectively use immune checkpoint inhibitor (ICI) drugs to treat cancer patients. However, T cells can either establish a protective antitumor response, or, in contrast, induce severe dysfunction that promotes disease progression in the majority of chronic infection patients. The contradiction depends, to a large degree, on the interaction between immune T cells and other tumor infiltrating cells or inflammatory cytokines around the tumor microenvironment. This review aims to summarize the current knowledge and regulatory mechanisms of CD8+T cell exhaustion, since reversing T cell exhaustion will definitely become a biomarker of clinical tumor immunotherapy. Abstract CD8+T cell exhaustion is a state of T cell dysfunction during chronic infection and tumor progression. Exhausted CD8+T cells are characterized by low effector function, high expression of inhibitory receptors, unique metabolic patterns, and altered transcriptional profiles. Recently, advances in understanding and interfering with the regulatory mechanisms associated with T cell exhaustion in tumor immunotherapy have brought greater attention to the field. Therefore, we emphasize the typical features and related mechanisms of CD8+T cell exhaustion and particularly the potential for its reversal, which has clinical implications for immunotherapy.
Investigation into microstructural evolution, mechanical and tribological properties of an aluminum surface composite developed using a severe plastic deformation technique

Aluminum based surface metal matrix composite was developed with 15% and 20% of TiCp reinforcement using multi-pass friction stirring process. The effect of TiC reinforcement and multiple FSP passes on microstructural evolution was characterized using optical, X-ray diffraction, electron microscopy, and electron backscattered diffraction techniques, while texture formation was analyzed using the neutron diffraction method. Hardness and tribological investigations were carried out to examine the mechanical behavior of the reinforced surface. A defect-free, uniformly reinforced composite surface with increased matrix-reinforcement interface was attained with 15% TiC after six passes. Hardness improved substantially to 215 HV due to the combined effect of zener pinning, grain refinement, uniformly dispersed reinforcement and increased dislocation density in the matrix. Better texture index was observed on the composite surface with Copper and S as dominating texture components. Significant wear resistance was exhibited by the composite at lower load due to strong adherence of TiC to the matrix, which however decreased with increase in loading conditions. Wear surface examination revealed that the mode of wear was predominantly abrasive.
Stein's two-stage procedure and exact consistency

Abstract Stein (1945 and 1949) achieved the exact probability coverage for a fixed-width confidence interval estimation of a normal mean when the variance is unknown. To achieve this type of exact result of “consistency” (in the Chow—Robbins (1965) sense), we notice that the assumption of normal distributions for the population is not essential. It can be replaced by less restrictive conditions on independence and pivotal nature of some suitable statistics. This is our Theorem 1. Examples are provided from negative exponential, symmetric normal (Rao, 1973, pp. 196–198) and normal populations. A similar type of problem is discussed for inverse Gaussian (see Folks & Chhikara, 1978) parameters. Modified two-stage procedures are proposed along the lines of Mukhopadhyay (1980) and are shown to be asymptotically “first-order efficient” (in the Ghosh—Mukhopadhyay (1981) sense). We also develop and study some properties of two-stage fixed-width confidence intervals constructed along the lines of Birnbaum & Healy .
Effect of heavy metal present in mixing water on properties and sulfate attack on blended cement mortar

The effect of lead (Pb) present in mixing water on compressive strength, setting times, soundness and sodium sulfate attack of high strength cement mortar was experimentally evaluated. Cement mortar specimens were cast using deionised water and lead (Pb) spiked demonized water for reference and test specimens as mixing waters respectively. On comparison with reference specimens, at higher concentrations of lead in mixing water, test samples had shown considerable loss of strength, and also their setting times had significantly increased. However, at 2000 mg/L concentration of lead (Pb), the compressive strength marginally increased. Apart that when reference specimens and test specimens immersed in various concentrations of sodium sulfate solution at different immersed ages, the loss in compressive strength was a little less in test specimens compared with reference specimens. XRD technique was employed to find out main compounds.
Nurses’ awareness of the availability of HIV and AIDS research

Background Hardship of human immunodeficiency virus (HIV) and acquired immunodeficiency syndrome (AIDS) transmission in Nigeria needs research-based strategies that scientifically inform research findings for relevant research advocacy. Aim This study aimed to enhance nurses’ awareness of the availability of HIV and AIDS research in Nigeria. Setting The research was carried out in a general hospital, a tertiary hospital in Ijebu Ode, Ogun State, Nigeria. Methods A qualitative technique was used, as well as an exploratory-descriptive design was employed. Semi-structured interviews were carried out. Three focus group interviews with seven participants in each group were used to gather data. Results This study showed the value of nurses’ awareness of the availability of HIV and AIDS research in overcoming obstacles to successfully controlling HIV and AIDS transmission in a hospital context in Nigeria. The study results demonstrated the nurses’ understanding of local and global research. The result of the study also demonstrated the essential role of collaboration with partners in enhancing nurses’ awareness of the availability of HIV and AIDS research in Nigeria. Conclusion The study found that nurses in Nigeria were usually unaware of their role in healthcare research development in the context of HIV and AIDS. They preferred to go with the flow of events. Contribution This study affirms the importance of nurses’ awareness of the availability of HIV and AIDS research in overcoming obstacles to successfully controlling HIV and AIDS transmission in a hospital context in Nigeria.
Grey Box Identification for the Free Electron Laser FLASH exploiting Symmetries of the RF-System

Abstract Appropriate models are essential to achieve high performance control for particle accelerators, which are the basis for free electron lasers. This papers deals with a significant reduction of the model complexity by exploiting physical symmetries of the plant. It is shown how models obeying the inherent SO (2) symmetry of the cavities and the radio frequency subsystem are set up and their parameters are identified from data generated at the FLASH facility. Validation of the symmetric models gives results which are competitive to those of black box models but with a reduced number of parameters.
Calculating Sample Sizes in the Presence of Confounding Variables

A major issue in the design of many studies is to determine the “required” number of observations. Much of the statistical literature on sample size estimation, particularly for medical studies, is devoted to considering a very simple design, involving the testing of the difference between proportions in two groups. Accommodation of potential confounding variables at the design stage is more difficult. This paper outlines a general theory based on generalized linear models for accommodating such variables. The theory is applied to three examples from medical research.
Model Ambiguities in Configurational Comparative Research

For many years, sociologists, political scientists, and management scholars have readily relied on Qualitative Comparative Analysis (QCA) for the purpose of configurational causal modeling. However, this article reveals that a severe problem in the application of QCA has gone unnoticed so far: model ambiguities. These arise when multiple causal models fare equally well in accounting for configurational data. Mainly due to the uncritical import of an algorithm that is unsuitable for causal modeling, researchers have typically been unaware of the whole model space. As a result, there exists an indeterminable risk for practically all QCA studies published in the last quarter century to have presented findings that their data did not warrant. Using hypothetical data, we first identify the algorithmic source of ambiguities and discuss to what extent they affect different methodological aspects of QCA. By reanalyzing a published QCA study from rural sociology, we then show that model ambiguities are not a mere theoretical possibility but a reality in applied research, which can assume such extreme proportions that no causal conclusions whatsoever are possible. Finally, the prevalence of model ambiguities is examined by performing a comprehensive analysis of 192 truth tables across 28 QCA studies published in applied sociology. In conclusion, we urge that future QCA practice ensures full transparency with respect to model ambiguities, both by informing readers of QCA-based research about their extent and by employing algorithms capable of revealing them.
Critical success factors of smart card technology in South African public hospitals

Background: Even though the government has set several admirable targets for raising the standard of healthcare, as highlighted by communities and media reports, public health institutions’ services continue to fall short of patients’ expectations and basic standards of care. For this reason, the general public has lost faith in the healthcare system. The public healthcare system in South Africa is completely dysfunctional and urgently needs to be transformed to serve the majority of those who use public hospitals.Objectives: The study aimed to improve healthcare for the majority of South Africans by investigating the critical success factors (CSFs) that influence the adoption of smart card technology (SCT) in South African public hospitals.Methods: A thorough review of peer-reviewed literature was conducted to determine potential barriers to adopting SCT. Furthermore, a hybrid model that combines the Health Unified Technology of Acceptance Theory (HUTAUT) model, DeLone and McLean IS success model (DM) and the diffusion of innovation (DOI) theory will be developed, validated and tested to identify the CSFs adoption of SCT in public hospitals in South Africa.Results: The validated research model has been developed to be adopted by nurses at public hospitals.Conclusion: This research will contribute to the development of a new framework that identifies the CSFs for SCT adoption in South African public hospitals.Contribution: The study’s results will make a special contribution to the body of knowledge in the fields of health informatics, particularly e-health.
MERGER-DRIVEN FUELING OF ACTIVE GALACTIC NUCLEI: SIX DUAL AND OF AGNs DISCOVERED WITH CHANDRA AND HUBBLE SPACE TELESCOPE OBSERVATIONS

Dual active galactic nuclei (AGNs) and offset AGNs are kpc-scale separation supermassive black holes pairs created during galaxy mergers, where both or one of the black holes are AGNs, respectively. These dual and offset AGNs are valuable probes of the link between mergers and AGNs but are challenging to identify. Here we present Chandra/ACIS observations of 12 optically selected dual AGN candidates at z < 0.34 ? > , where we use the X-rays to identify AGNs. We also present Hubble Space Telescope/Wide Field Camera 3 observations of 10 of these candidates, which reveal any stellar bulges accompanying the AGNs. We discover a dual AGN system with separation Δ x = 2.2 ? > kpc, where the two stellar bulges have coincident [O iii] λ5007 and X-ray sources. This system is an extremely minor merger (460:1) that may include a dwarf galaxy hosting an intermediate mass black hole. We also find six single AGNs, and five systems that are either dual or offset AGNs with separations Δ x < 10 ? > kpc. Four of the six dual AGNs and dual/offset AGNs are in ongoing major mergers, and these AGNs are 10 times more luminous, on average, than the single AGNs in our sample. This hints that major mergers may preferentially trigger higher luminosity AGNs. Further, we find that confirmed dual AGNs have hard X-ray luminosities that are half of those of single AGNs at fixed [O iii] λ5007 luminosity, on average. This could be explained by high densities of gas funneled to galaxy centers during mergers, and emphasizes the need for deeper X-ray observations of dual AGN candidates.
Influence of Gut Microbiota on Metabolism of Bisphenol A, a Major Component of Polycarbonate Plastics

Bisphenol A (BPA) is a major component of polycarbonate plastics and epoxy resins. While many studies have investigated the effect BPA exposure has upon changes in gut microbial communities, the influence of gut microbiota on an organism’s ability to metabolize BPA remains comparatively unexplored. To remedy this, in this study, Sprague Dawley rats were intermittently (i.e., at a 7-day interval) or continuously dosed with 500 μg BPA/kg bw/day for 28 days, via oral gavage. In the rats which underwent the 7-day interval BPA exposure, neither their metabolism of BPA nor their gut microbiota structure changed greatly with dosing time. In contrast, following continuous BPA exposure, the relative level of Firmicutes and Proteobacteria in the rats’ guts significantly increased, and the alpha diversity of the rats’ gut bacteria was greatly reduced. Meanwhile, the mean proportion of BPA sulfate to total BPA in rat blood was gradually decreased from 30 (on day 1) to 7.4% (by day 28). After 28 days of continuous exposure, the mean proportion of BPA glucuronide to total BPA in the rats’ urine elevated from 70 to 81%, and in the rats’ feces the mean proportion of BPA gradually decreased from 83 to 65%. Under continuous BPA exposure, the abundances of 27, 25, and 24 gut microbial genera were significantly correlated with the proportion of BPA or its metabolites in the rats’ blood, urine, and feces, respectively. Overall, this study principally aimed to demonstrate that continuous BPA exposure disrupted the rats’ gut microbiota communities, which in turn altered the rats’ metabolism of BPA. These findings contribute to the better understanding of the metabolism of BPA in humans.
Organic Nanodelivery Systems as a New Platform in the Management of Breast Cancer: A Comprehensive Review from Preclinical to Clinical Studies

Breast cancer accounts for approximately 25% of cancer cases and 16.5% of cancer deaths in women, and the World Health Organization predicts that the number of new cases will increase by almost 70% over the next two decades, mainly due to an ageing population. Effective diagnostic and treatment strategies are, therefore, urgently required for improving cure rates among patients since current therapeutic modalities have many limitations and side effects. Nanomedicine is evolving as a promising approach for cancer management, including breast cancer, and various types of organic and inorganic nanomaterials have been investigated for their role in breast cancer diagnosis and treatment. Following an overview on breast cancer characteristics and pathogenesis and challenges of the current treatment strategies, the therapeutic potential of biocompatible organic-based nanoparticles such as liposomes and polymeric micelles that have been tested in breast cancer models are reviewed. The efficacies of different drug delivery and targeting strategies are documented, ranging from synthetic to cell-derived nanoformulations together with a summary of the interaction of nanoparticles with externally applied energy such as radiotherapy. The clinical translation of nanoformulations for breast cancer treatment is summarized including those undergoing clinical trials.