Miracle-dz/UniFAR-FTUs huggingface dataset:
A Characterization of Finite Simple Groups by the Degrees of Vertices of Their Prime Graphs

If G is a finite group, we define its prime graph Γ(G) as follows. The vertices of Γ(G) are the primes dividing the order of G and two distinct vertices p, q are joined by an edge, denoted by p~q, if there is an element in G of order pq. Assume $|G|=p_1^{\alpha_1}p_2^{\alpha_2}\cdots p_k^{\alpha_k}$ with primes p1<p2<⋯<pk and natural numbers αi. For p∈π(G), let the degree of p be deg(p)=|{q∈π(G)|q~p}|, and D(G):=(deg(p1), deg(p2),…, deg(pk)). In this paper, we prove that if G is a finite group such that D(G)=D(M) and |G|=|M|, where M is one of the following simple groups: (1) sporadic simple groups, (2) alternating groups Ap with p and p-2 primes, (3) some simple groups of Lie type, then G≅M. Moreover, we show that if G is a finite group with OC(G)={29.39. 5.7, 13}, then G≅S6(3) or O7(3), and finally, we show that if G is a finite group such that |G|=29.39. 5.7. 13 and D(G)=(3,2,2,1,0), then G≅S6(3) or O7(3).
Dialogues Concerning Two New Sciences

Galileo Galilei was a great scientist, and therefore not afraid of causing controversy, even if he had to pay a great price. His public advocacy of the Copernican over the Aristotelian system of the universe flew directly in the face of biblical authority and ecclesiastical tradition. Condemned and placed under house arrest by the Inquisition, Galileo nonetheless devoted his last years to the completion of his "Dialogues Concerning Two New Sciences", which deals with motion and the resistance of solids. The "Two New Sciences", which Galileo called his most important work, may be regarded as the summary statement of a life devoted to scientific experimentation and free inquiry un-trammeled by tradition and authority.
PAG-TSN: Ridership Demand Forecasting Model for Shared Travel Services of Smart Transportation

With the increasing popularity of cab services such as Didi and Uber, cities are faced with the challenge of high carbon emissions and traffic congestion. Ride-sharing services, as a novel green mode of transportation, have emerged as a key technology in smart transportation for addressing these problems. The implementation of ride-sharing is predicated on an accurate ridership demand forecasting model, which can effectively prevent vehicle resource waste, alleviate traffic congestion, and reduce carbon emissions. In this paper, a periodic attentional graph convolutional spatio-temporal network model (PAG-TSN) is proposed to predict regional ridership demand. Specifically, the model is trained using a large amount of GPS data and user demand data collected by the travel service provider. PAG-TSN consists of two parts: the bicomponent attention graph convolution model (BAT-GCN) and the periodic attentional gated recurrent unit model (PA-GRU). The former uses GCN to extract spatial features from pointwise and edgewise graphs; the latter uses the spatial feature vectors extracted from the former with external information as input, and uses GRU to extract temporal features from feature data of different periods, and finally uses attention mechanism and POI requirement correlation to integrate the extracted spatio-temporal information to derive prediction results. Extensive experiments and evaluations on the CD2Date and XA2Date datasets show that PAG-TSN outperforms other baseline models in accurately predicting regional ridership demand, with MAPE and RMSE values of 0.1147 and 5.56, respectively.
Work from home or office during the COVID-19 pandemic: The different chain mediation models of perceived organizational support to the job performance

With the coronavirus pandemic in 2019 (COVID-19), work from home (WFH) has become a frequent way of responding to outbreaks. Across two studies, we examined how perceived organizational support influences job performance when employees work in office or work from home. In study 1, we conducted a questionnaire survey of 162 employees who work in office. In study 2, we conducted a questionnaire survey of 180 employees who work from home. We found that perceived organizational support directly affected job performance when employees work in office. When employees work from home, perceived organizational support could not affect job performance directly. However, it could influence job performance indirectly through the separate mediating effects of job satisfaction and work engagement. These findings extend our understanding of the association of perceived organizational support and job performance and enlighten enterprises on improving employees' job performance during the COVID-19 pandemic.
Neutrino Telescopes in Antarctica

Abstract It is hoped that in the near future neutrino astronomy will reach throughout and beyond our galaxy and make measurements relevant to cosmology, astrophysics, cosmic-ray and particle physics. The construction of a high-energy neutrino telescope requires a huge volume of very transparent, deeply buried material such as ocean water or ice, which acts as the medium for detecting the particles. I will describe two experiments using Antarctic ice as this medium: the AMANDA experiment employing photomultiplier tubes and RICE utilising radio receivers.
Elastic Provisioning of Network and Computing Resources at the Edge for IoT Services

The fast growth of Internet-connected embedded devices demands new system capabilities at the network edge, such as provisioning local data services on both limited network and computational resources. The current contribution addresses the previous problem by enhancing the usage of scarce edge resources. It designs, deploys, and tests a new solution that incorporates the positive functional advantages offered by software-defined networking (SDN), network function virtualization (NFV), and fog computing (FC). Our proposal autonomously activates or deactivates embedded virtualized resources, in response to clients’ requests for edge services. Complementing existing literature, the obtained results from extensive tests on our programmable proposal show the superior performance of the proposed elastic edge resource provisioning algorithm, which also assumes an SDN controller with proactive OpenFlow behavior. According to our results, the maximum flow rate for the proactive controller is 15% higher; the maximum delay is 83% smaller; and the loss is 20% smaller compared to when the non-proactive controller is in operation. This improvement in flow quality is complemented by a reduction in control channel workload. The controller also records the time duration of each edge service session, which can enable the accounting of used resources per session.
Large-eddy simulation of three-dimensional dunes in a steady, unidirectional flow. Part 2. Flow structures

Abstract We performed large-eddy simulations of the flow over a series of three-dimensional (3D) dunes at laboratory scale. The bedform three-dimensionality was imposed by shifting a standard two-dimensional (2D) dune shape in the streamwise direction according to a sine wave. The turbulence statistics were discussed in Part 1 of this article (Omidyeganeh & Piomelli, J. Fluid Mech., vol. 721, 2013, pp. 454–483). Coherent flow structures and their statistics are discussed concentrating on two cases with the same crestline amplitudes and wavelengths but different crestline alignments: in-phase and staggered. The present paper shows that the induced large-scale mean streamwise vortices are the primary factor that alters the features of the instantaneous flow structures. Wall turbulence is insensitive to the crestline alignment; alternating high- and low-speed streaks appear in the internal boundary layer developing on the stoss side, whereas over the node plane (the plane normal to the spanwise direction at the node of the crestline), they are inclined towards the lobe plane (the plane normal to the spanwise direction at the most downstream point of the crestline) due to the mean spanwise pressure gradient. Spanwise vortices (rollers) generated by Kelvin–Helmholtz instability in the separated shear layer appear regularly over the lobe with much larger length scale than those over the saddle (the plane normal to the spanwise direction at the most upstream point of the crestline). Rollers over the lobe may extend to the saddle plane and affect the reattachment features; their shedding is more frequent than in 2D geometries. Vortices shed from the separated shear layer in the lobe plane undergo a three-dimensional instability while being advected downstream, and rise toward the free surface. They develop into a horseshoe shape (similar to the 2D case) and affect the whole channel depth, whereas those generated near the saddle are advected downstream and toward the bed. When the tip of such a horseshoe reaches the free surface, the ejection of flow at the surface causes ‘boils’ (upwelling events on the surface). Strong boil events are observed on the surface of the lobe planes of 3D dunes more frequently than in the saddle planes. They also appear more frequently than in the corresponding 2D geometry. The crestline alignment of the dune alters the dynamics of the flow structures, in that they appear in the lobe plane and are advected towards the saddle plane of the next dune, where they are dissipated. Boil events occur at a higher frequency in the staggered alignment, but with less intensity than in the in-phase alignment.
The splitting of separatrices for analytic diffeomorphisms

Abstract We study families of diffeomorphisms close to the identity, which tend to it when the parameter goes to zero, and having homoclinic points. We consider the analytical case and we find that the maximum separation between the invariant manifolds, in a given region, is exponentially small with respect to the parameter. The exponent is related to the complex singularities of a flow which is taken as an unperturbed problem. Finally several examples are given.
Toroidal stellarator diode: discharge features and electron transport

The radial dependences of the emission current I em of a small thermionic emitter at different anode voltages, as well as the current–voltage characteristics (CVCs) and the dependence of I em on the magnetic field B were measured to investigate the relationship between the electron transport and the E×B electric and magnetic fields in the toroidal stellarator diode system in stellarator-type magnetic traps (Uragan-3M and Uragan-2M torsatrons). It is demonstrated that the electron transport in the discharge is controlled to a large measure by an applied radial electric field, while the current jump (nonlinear dynamic behaviour) in the discharge is due to the attainment of the critical value by the radial electric field and to the occurrence of the ionization process. A phenomenological description of the CVCs showing a hysteresis behaviour is presented. A large variety of electron transport scalings (I em– B dependences) were obtained in two different torsatrons.
Ultra-high-resolution observations of circumstellar K i and C2 around the post-AGB star HD 56126

We have used the Ultra-High-Resolution Facility (UHRF) at the AAT, operating at a resolution of 0.35 km s−1 (FWHM), to observe K I and C2 absorption lines arising in the circumstellar environment of the post-AGB star HD 56126. We find three narrow circumstellar absorption components in K I, two of which are also present in C2. We attribute this velocity structure to discrete shells resulting from multiple mass-loss events from the star. The very high spectral resolution has enabled us to resolve the intrinsic linewidths of these narrow lines for the first time, and we obtain velocity dispersions (b-values) of 0.2–0.3 km s−1 for the K I components, and 0.54 ± 0.03 km s−1 for the strongest (and best defined) C2 component. These correspond to rigorous kinetic temperature upper limits of 211 K for K I and 420 K for C2, although the b-value ratio implies that these two species do not co-exist spatially. The observed degree of rotational excitation of C2 implies low kinetic temperatures (Tk ≈10 K) and high densities (n ≈ 106 to 107 cm−3) within the shell responsible for the main C2 component. Given this low temperature, the line profiles then imply either mildly supersonic turbulence or an unresolved velocity gradient through the shell.
GRRIEn analysis: a data science cheat sheet for earth scientists learning from global earth observations

Globally available environmental observations (EOs), specifically from satellites and coupled earth systems models, represent some of the largest datasets of the digital age. As the volume of global EOs continues to grow, so does the potential of this data to help earth scientists discover trends and patterns in earth systems at large spatial scales. To leverage global EOs for scientific insight, earth scientists need targeted and accessible exposure to skills in reproducible scientific computing and spatiotemporal data science, and to be empowered to apply their domain understanding to interpret data-driven models for knowledge discovery. The GRRIEn (Generalizable, Reproducible, Robust, and Interpreted Environmental) analysis framework was developed to prepare earth scientists with an introductory statistics background and limited/no understanding of programming and computational methods to use global EOs to successfully generalize insights from local/regional field measurements across unsampled times and locations. GRRIEn analysis is generalizable, meaning results from a sample are translated to landscape scales by combining direct environmental measurements with global EOs using supervised machine learning; robust, meaning that model shows good performance on data with scale-dependent feature and observation dependence; reproducible, based on a standard repository structure so that other scientists can quickly and easily replicate the analysis with a few computational tools; and interpreted, meaning that earth scientists apply domain expertise to ensure that model parameters reflect a physically plausible diagnosis of the environmental system. This tutorial presents standard steps for achieving GRRIEn analysis by combining conventions of rigor in traditional experimental design with the open-science movement.
Fecal Metagenomics and Metabolomics Identifying Microbial Signatures in Non-Alcoholic Fatty Liver Disease

The frequency of non-alcoholic fatty liver disease (NAFLD) has intensified, creating diagnostic challenges and increasing the need for reliable non-invasive diagnostic tools. Due to the importance of the gut–liver axis in the progression of NAFLD, studies attempt to reveal microbial signatures in NAFLD, evaluate them as diagnostic biomarkers, and to predict disease progression. The gut microbiome affects human physiology by processing the ingested food into bioactive metabolites. These molecules can penetrate the portal vein and the liver to promote or prevent hepatic fat accumulation. Here, the findings of human fecal metagenomic and metabolomic studies relating to NAFLD are reviewed. The studies present mostly distinct, and even contradictory, findings regarding microbial metabolites and functional genes in NAFLD. The most abundantly reproducing microbial biomarkers include increased lipopolysaccharides and peptidoglycan biosynthesis, enhanced degradation of lysine, increased levels of branched chain amino acids, as well as altered lipid and carbohydrate metabolism. Among other causes, the discrepancies between the studies may be related to the obesity status of the patients and the severity of NAFLD. In none of the studies, except for one, was diet considered, although it is an important factor driving gut microbiota metabolism. Future studies should consider diet in these analyses.
Smectite clay minerals: properties and uses

The physicochemical properties of smectite clay minerals that determine their industrial utilization are reviewed. Smectite is the name used for a group of phyllosilicate mineral species, the most important of which are montmorillonite, beidellite, nontronite, saponite and hectorite. These and several other less common species are differentiated by variations in chemical composition involving substitutions of Al for Si in tetrahedral cation sites and Al, Fe, Mg and Li in octahedral cation sites. Smectite clays have a variable net negative charge, which is balanced by Na, Ca, Mg and, or, H adsorbed externally on interlamellar surfaces. The structure, chemical composition, exchangeable ion type and small crystal size of smectite clays are responsible for several unique properties, including a large chemically active surface area, a high cation exchange capacity, interlamellar surfaces having unusual hydration characteristics, and sometimes the ability to modify strongly the flow behaviour of liquids. In terms of major industrial and chemical uses, natural smectite clays can be divided into three categories, Na smectites, Ca-Mg smectites and Fuller’s or acid earths. Large volumes of Na smectites and Na-exchanged Ca-M g smectites and Fuller’s earth are directly used in the foundry, oil well drilling, wine, and iron ore and feed pelletizing industries, and are also used in civil engineering to impede water movement. Significant volumes of Na smectites are used for various purposes in the manufacturing of many industrial, chemical and consumer products. Large quantities of Ca-M g smectites are used directly in iron foundries, in agricultural industries and for filtering and decolorizing various types of oils. A significant fraction of the Ca-M g smectites used for decolorizing has been acid treated. Large volumes of Fuller’s or acid earths are commercially used for preparing animal litter trays and oil and grease absorbents, as carriers for insecticides, and for decolorizing of oils and fats. Natural Na smectites occur in commercial quantities in only a few places, but Ca-M g smectite and Fuller’s earth deposits of considerable size occur on almost every continent.
Leveraging paradigms to foster theoretical contributions in information systems research

Despite all our theorizing efforts and the importance that we and our major information systems (IS) journals ascribe to theory development, making theoretical contributions to our field remains challenging. Recognizing that we cannot develop better theories without improving how we theorize, our field is now engaged in an in-depth discussion of the theorizing process. This manuscript contributes to this discussion by exposing why and how leveraging paradigms when theorizing can foster theoretical contributions within our field. Its premise is that we need to stop working within the confines of a limited set of well-entrenched paradigms and move beyond what is known as true and correct to come up with improvements that significantly alter the way we come to rationalize, explain, and master our world. Anchored on this premise, this manuscript begins by discussing the origin, role, and features of paradigms as well as explaining that they are of three different but interrelated forms (i.e., metaphysical, sociological, and artefactual). The manuscript then adds to this understanding of paradigms by detailing the unique relationships that tie paradigms of each form to theory and explaining why taking advantage of these unique bonds when theorizing may help us make theoretical contributions. Lastly, to foster theoretical contributions within our field, this manuscript proposes a set of guidelines to help us leverage paradigms of the different forms when theorizing.
Meta-Analysis of the Effects of Biochar Application on the Diversity of Soil Bacteria and Fungi

Biochar is increasingly being used for soil improvement, but the effects on microbial diversity in soil are still ambiguous due to contrasting results reported in the literature. We conducted a meta-analysis to clarify the effect of biochar addition on soil bacterial and fungal diversity with an increase in Shannon or Chao1 index as the outcome. Different experimental setups, quantitative levels of biochar addition, various biochar source materials and preparation temperatures, and the effect of natural precipitation in field experiments were the investigated variables. From a total of 95 publications identified for analysis, 384 datasets for Shannon index and 277 datasets for Chao1 index were extracted that described the bacterial diversity in the soils, of which field experiments and locations in China dominated. The application of biochar in soil significantly increased the diversity of soil bacteria but it had no significant effect on the diversity of fungi. Of the different experimental setups, the largest increase in bacterial diversity was seen for field experiments, followed by pot experiments, but laboratory and greenhouse settings did not report a significant increase. In field experiments, natural precipitation had a strong effect, and biochar increased bacterial diversity most in humid conditions (mean annual precipitation, MAP > 800 mm), followed by semi-arid conditions (MAP 200–400 mm). Biochar prepared from herbaceous materials was more effective to increase bacterial diversity than other raw materials and the optimal pyrolysis temperature was 350–550 °C. Addition of biochar at various levels produced inconclusive data for Chao1 and Shannon indices, and its effect was less strong than that of the other assessed variables.
The Square Roots of 2 × 2 Matrices

Introduction In a recent article MacKinnon [1] describes four methods that may be used to find square roots of 2 X 2 matrices. The first of these methods requires that the matrix for which the square roots are sought be diagonalizable and, subsequently, this method was used by Scott [2] to determine all the square roots of 2 X 2 matrices. A surprising conclusion is that scalar 2 X 2 matrices possess double-infinities of square roots whereas nonscalar 2 X 2 matrices have only a finite number of square roots. The purpose of this article is to show how the Cayley-Hamilton theorem may be used to determine explicit formulae for all the square roots of 2 X 2 matrices. These formulae indicate exactly when a 2 X 2 matrix has square roots, and the number of such roots. By definition, the square roots of a 2 X 2 matrix, A, are those 2 X 2 matrices, X, for which