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This study reveals the competitive evolutionary process of the main driving factors in the early, middle and late stages of sandstorms, as shear turbulence becomes dominant and is then suppressed by enhanced thermal stability, based on quadrant analysis of the sand-laden turbulent wind field acquired from field observations over the entire sandstorm process. Moreover, the self-organized state of multiscale structures in the energy-containing region of the sand-laden turbulence is found to change significantly as the sandstorm develops. The logarithmic scaling law that governs the cumulative turbulent kinetic energy for the non-stationary flow in the early and late stages of the sandstorm is different from the existing theoretical formula. The corresponding rate of increase in the cumulative kinetic energy with increasing scale is much higher in these stages than in the middle stage of the sandstorm with steady flow. The change in self-organized state of turbulence is responsible for the flow acceleration and the thermal superimposed effect, rather than the addition of sand particles.
A large body of research demonstrates positive impacts of the Coping Power Program as a preventive intervention for youth behavioral outcomes, but potential collateral effects for caregivers is less known. The current study examined whether the youth-focused Coping Power Program can have a secondary impact on caregiver self-reported symptoms of depression and in turn result in longer-term impacts on child disruptive behavior problems including aggression, conduct problems and hyperactivity. Data from 360 youth/caregiver pairs across 8 waves of data (grades 4 through 10) were analyzed. We used two methodological approaches to (a) assess indirect effects in the presence of potential bidirectionality using timepoint-to-timepoint dynamic effects under Autoregressive Latent Trajectory modeling and (b) estimate scale scores in the presence of measurement non-invariance. Results showed that individually delivered Coping Power (ICP) produced greater direct effects on conduct problems and indirect effects on general externalizing and hyperactivity (through reductions in caregiver self-reported symptoms of depression), compared to group Coping Power (GCP). In comparison to GCP, ICP produced similar direct effects on reductions in caregiver depression. Child-focused prevention interventions can have an indirect impact on caregiver depression, which later shows improvements in longer-term reductions for child disruptive problems.
Impressed by Friedrich Nietzsche's critique of liberalism but alarmed by its consequences, Leo Strauss turned in the 1930s to the medieval Islamic philosophers (falāsifa). A review of a key cleavage in their political philosophy—reflected in the contrasting positions of Ibn Rushd and Ibn Sina—identifies the fundamental alternatives Strauss found available to him on the role of religion in politics, and on the necessity and efficacy of political activism more generally. It thus illuminates the trajectory of Strauss's thoughts on the relationship between reason and revelation: from an initial appreciation for the “golden mean” between Nietzsche and liberalism he believed he had found in the writings of al-Farabi and Ibn Rushd, to a more apolitical “Avicennan” stance after his arrival in America. This last, it is suggested, was a contingent stance requiring reconsideration in light of new circumstances in American politics today.
Understanding how youth perceive household economic hardship and how it relates to their behavior is vital given associations between hardship and behavioral development. Yet, most studies ignore youth’s own perceptions of economic hardship, instead relying solely on caregiver reports. Moreover, the literature has tended to treat economic hardship as a stable force over time, rather than a volatile one that varies month-to-month. This study addressed extant limitations by collecting monthly measures of economic hardship, specifically caregiver- and youth-reported material deprivation and youth-reported financial stress, and youth internalizing and externalizing problems from 104 youth–caregiver dyads (youth: 14–16 years, 55% female, 37% Black, 43% White) over nine months. We examined month-to-month variability of these constructs and how youth-reports of material deprivation and financial stress predicted their behavior problems, controlling for caregiver-reports of material deprivation. We found that hardship measures varied month-to-month (ICCs = 0.69–0.73), and youth-reported material deprivation positively predicted internalizing when examining both within- and between-individual variability (β = .19–.47). Youth-reported financial stress positively predicted within-individual variation in externalizing (β = .18), while youth reports of material deprivation predicted externalizing when looking between families (β = .41). Caregiver-reported material deprivation was unrelated to youth behavior when accounting for youth perceptions of economic hardship.
We prove that any hyper-Kähler sixfold $K$ of generalized Kummer type has a naturally associated manifold $Y_K$ of $\mathrm {K}3^{[3]}$ type. It is obtained as crepant resolution of the quotient of $K$ by a group of symplectic involutions acting trivially on its second cohomology. When $K$ is projective, the variety $Y_K$ is birational to a moduli space of stable sheaves on a uniquely determined projective $\mathrm {K}3$ surface $S_K$. As an application of this construction we show that the Kuga–Satake correspondence is algebraic for the K3 surfaces $S_K$, producing infinitely many new families of $\mathrm {K}3$ surfaces of general Picard rank $16$ satisfying the Kuga–Satake Hodge conjecture.
When a liquid jet plunges into a pool, it can generate a bubble-laden jet flow underneath the surface. This common and simple phenomenon is investigated experimentally for circular jets to illustrate and quantify the role played by the net gas/liquid void fraction on the maximum bubble penetration depth. It is first shown that an increase in either the impact diameter or the jet fall height to diameter ratio at constant impact momentum leads to a reduction in the bubble cloud size. By measuring systematically the local void fraction using optical probes in the biphasic jet, it is then demonstrated that this effect is a direct consequence of the increase in air content within the cloud. A simple momentum balance model, including only inertia and the buoyancy force, is shown to predict the bubble cloud depth without any fitting parameters. Finally, a Froude number based on the bubble terminal velocity, the cloud depth and also the net void fraction is introduced to propose a simple criterion for the threshold between the inertia-dominated and buoyancy-dominated regimes.
The coffee berry borer, Hypothenemus hampei (Ferrari) (Coleoptera: Curculionidae), is a major destructive insect pest of coffee, which impacts the coffee crops negatively. As a draft genome has been completed for this insect, most molecular studies on gene transcriptional levels under different experimental conditions will be conducted using real-time reverse-transcription quantitative polymerase chain reactions (RT-qPCR). However, the lack of suitable internal reference genes will affect the accuracy of RT-qPCR results. In this study, the expression stability of nine candidate reference genes was evaluated under different developmental stages, temperature stress, and Beauveria bassiana infection. Data analyses were completed by four commonly used programs, BestKeeper, NormFinder, geNorm, and RefFinder. The result showed that RPL3 and EF1α combination were recommended as the most stable reference genes for developmental stages. EF1α and RPS3a combination were the top two stable reference genes for B. bassiana infection. RPS3a and RPL3 combination performed as the optimal reference genes both in temperature stress and all samples. Our results should provide a good foundation for the expression profile analyses of target genes in the future, especially for molecular studies on insect genetic development, temperature adaptability, and immune mechanism to entomogenous fungi in H. hampei.
Bees play a significant role in the health of terrestrial ecosystems. The decline of bee populations due to colony collapse disorder around the world constitutes a severe ecological danger. Maintaining high yield of honey and understanding of bee behaviour necessitate constant attention to the hives. Research initiatives have been taken to establish monitoring programs to study the behaviour of bees in accessing their habitat. Monitoring the sanitation and development of bee brood allows for preventative measures to be taken against mite infections and an overall improvement in the brood's health. This study proposed a precision beekeeping method that aims to reduce bee colony mortality and improve conventional apiculture through the use of technological tools to gather, analyse, and understand bee colony characteristics. This research presents the application of advanced digital image processing with computer vision techniques for the visual identification and analysis of bee brood at various developing stages. The beehive images are first preprocessed to enhance the important features of object. Further, object is segmented and classified using computer vision techniques. The research is carried out with the images containing variety of immature brood stages. The suggested method and existing methods are tested and compared to evaluate efficiency of proposed methodology.
DeMarco, Krieger, and Ye conjectured that there is a uniform bound B, depending only on the degree d, so that any pair of holomorphic maps $f, g :{\mathbb {P}}^1\to {\mathbb {P}}^1$ with degree $d$ will either share all of their preperiodic points or have at most $B$ in common. Here we show that this uniform bound holds for a Zariski open and dense set in the space of all pairs, $\mathrm {Rat}_d \times \mathrm {Rat}_d$, for each degree $d\geq 2$. The proof involves a combination of arithmetic intersection theory and complex-dynamical results, especially as developed recently by Gauthier and Vigny, Yuan and Zhang, and Mavraki and Schmidt. In addition, we present alternate proofs of the main results of DeMarco, Krieger, and Ye [Uniform Manin-Mumford for a family of genus 2 curves, Ann. of Math. (2) 191 (2020), 949–1001; Common preperiodic points for quadratic polynomials, J. Mod. Dyn. 18 (2022), 363–413] and of Poineau [Dynamique analytique sur$\mathbb {Z}$II : Écart uniforme entre Lattès et conjecture de Bogomolov-Fu-Tschinkel, Preprint (2022), arXiv:2207.01574 [math.NT]]. In fact, we prove a generalization of a conjecture of Bogomolov, Fu, and Tschinkel in a mixed setting of dynamical systems and elliptic curves.
We prove that after inverting the Planck constant $h$, the Bezrukavnikov–Kaledin quantization $(X, {\mathcal {O}}_h)$ of symplectic variety $X$ in characteristic $p$ with $H^2(X, {\mathcal {O}}_X) =0$ is Morita equivalent to a certain central reduction of the algebra of differential operators on $X$.
Analytical expressions for the velocity field and the effective slip length of pressure-driven Stokes flow through slippery pipes and annuli with rotationally symmetrical longitudinal slits are derived. Specifically, the developed models incorporate a finite local slip length and constant shear stress along the slits, and thus go beyond the assumption of perfect slip employed commonly for superhydrophobic surfaces. Thereby, they provide the possibility to assess the influence of both the viscosity of the air or other fluid that is modelled to fill the slits as well as the influence of the micro-geometry of these slits. First, expressions for tubes and annular pipes with superhydrophobic or slippery walls are provided. Second, these solutions are combined to a tube-within-a circular-pipe scenario, where one fluid domain provides a slip to the other. This scenario is interesting as an application to achieve stable fluid–fluid interfaces. With respect to modelling, it illustrates the specification of the local slip length depending on a linked flow field. The comparison of the analytically calculated solutions with numerical simulations shows excellent agreement. The results of this paper thus represent an important instrument for the design and optimization of slippage along surfaces in circular geometries.