Stripe Orientation Research Articles

How the zebra got its stripes: Curvature-dependent diffusion orients Turing patterns on three-dimensional surfaces.

Many animals have patterned fur, feathers, or scales, such as the stripes of a zebra. Turing models, or reaction-diffusion systems, are a class of mathematical models of interacting species that have been successfully used to generate animal-like patterns for many species. When diffusion of the inhibitor is high enough relative to the activator, a diffusion-driven instability can spontaneously form patterns. However, it is not just the type of pattern but also the orientation that matters, and it remains unclear how patterns are oriented in practice. Here, we propose a mechanism by which the curvature of the surface influences the rate of diffusion, and can recapture the correct orientation of stripes on models of a zebra and of a cat in numerical simulations. Previous work has shown how anisotropic diffusion can give stripe forming reaction-diffusion systems a bias in orientation. From the observation that zebra stripes run around the direction of highest curvature, that is around the torso and legs, we apply this result by modifying the anisotropic diffusion rates based on the local curvature. These results show how local geometry can influence the reaction dynamics to give robust, global-scale patterns. Overall, this model proposes a coupling between the system geometry and reaction-diffusion dynamics that can give global control over the patterning by using only local curvature information. Such a model can give shape and positioning information in animal development without the need for spatially dependent morphogen gradients.

Destriping model for adaptive removal of arbitrary oriented stripes in remote sensing images

Abstract Destriping in remote sensing image processing remains a challenging problem, particularly when dealing with stripe noise of arbitrary orientations. Conventional methods struggle to eliminate oblique stripes, leaving a crucial gap in the production of higher-level remote sensing products. In response, we propose a novel destriping model, the Adaptive Stripe Noise Removal (ASNR) Method, designed to adapt to different orientations of stripe noise, aiming for accuracy, robustness, speed, and simplicity. The paper first addresses the conventional challenges in stripe removal, emphasizing the unintended loss of information during the process. To overcome this, we conduct a detailed study of stripe noise characteristics, employing traditional Fast Fourier Transform (FFT) for stripe orientation approximation. However, conventional techniques using spatial representations risk damaging detailed structures. To go beyond these limitations, the proposed method combines spectral processing technology with an image guidance mechanism. This approach aims to generate a guided image that retains both denoised features and important details. In the frequency domain, the method corrects the stripe image by estimating a guidance image. Experimental results, both qualitative and quantitative, demonstrate the superiority and stability of the proposed method in removing stripe noise and preserving image details without introducing artifacts. The novel approach fills a critical gap in destriping methods, offering a fast, accurate, and adaptable solution for arbitrary orientations of stripe noise in remote sensing images.

A comprehensive model for viscoplastic flows in channels with a patterned wall: longitudinal, transverse and oblique flows

We develop a comprehensive model for the creeping Poiseuille Bingham flow in channels equipped with a patterned wall, i.e. decorated with grooves or stripes that may represent a superhydrophobic (SH) or a chemically patterned (CP) surface, respectively, with longitudinal, transverse and oblique groove (stripe) orientations with respect to the applied pressure gradient. We rely on the Navier slip law to model the boundary condition on the slippery grooves. We develop semi-analytical, explicit-form and complementary computational fluid dynamics models, with solutions that have reasonable agreement. In contrast to its Newtonian analogue, a distinct solution for the oblique configuration, with an a priori unknown transform matrix, must be developed due to the viscoplastic nonlinear rheology. Our focus is to systematically analyse the effects of the Bingham number ( $B$ ), slip number ( $b$ ), groove periodicity length ( $\ell$ ), slip area fraction ( $\varphi$ ) and groove orientation angle ( $\theta$ ), on the slip velocities, effective slip length ( $\chi$ ), slip angle difference ( $\theta -s$ ), mixing index ( $I_M$ ), flow anisotropy and flow regimes. In particular, we demonstrate that, as $B$ increases, the maximum values of the shear component of $\chi$ , $\theta -s$ and $I_M$ occur progressively at smaller values of $\theta$ , compared with their Newtonian counterparts.

Helitronics as a potential building block for classical and unconventional computing

Magnetic textures are promising candidates for unconventional computing due to their non-linear dynamics. We propose to investigate the rich variety of seemingly trivial lamellar magnetic phases, e.g. helical, spiral, stripy phase, or other one-dimensional soliton lattices. These are the natural stray field-free ground states of almost every magnet. The order parameters of these phases may be of potential interest for both classical and unconventional computing, which we refer to as helitronics. For the particular case of a chiral magnet and its helical phase, we use micromagnetic simulations to demonstrate the working principles of all-electrical (i) classical binary memory cells and (ii) memristors and artificial synapses, based on the orientation of the helical stripes.

Elastic-stripe formation at electronic transitions

We investigate the possibility of a striped inhomoegenous phase occurring as an electronic system with an order parameter linearly coupled to the elastic degrees of freedom is tuned through the electronic phase transition. We find that in finite systems where boundary conditions create an eleastic incompatibility, a stripe pattern may emerge in the vicinity of the electronic transition. Stripes are stabilized when the gained elastic energy overcomes the typical electronic and domain wall energy costs. In thin film geometries, the stripes are found to extend across the entire depth of the system. We also study the behavior of the phase fraction across the spinodal region of a first order phase transition. The orientation of stripes and the possibility of more complicated patterns is also discussed.

Analysis of emergent patterns in crossing flows of pedestrians reveals an invariant of 'stripe' formation in human data.

When two streams of pedestrians cross at an angle, striped patterns spontaneously emerge as a result of local pedestrian interactions. This clear case of self-organized pattern formation remains to be elucidated. In counterflows, with a crossing angle of 180°, alternating lanes of traffic are commonly observed moving in opposite directions, whereas in crossing flows at an angle of 90°, diagonal stripes have been reported. Naka (1977) hypothesized that stripe orientation is perpendicular to the bisector of the crossing angle. However, studies of crossing flows at acute and obtuse angles remain underdeveloped. We tested the bisector hypothesis in experiments on small groups (18-19 participants each) crossing at seven angles (30° intervals), and analyzed the geometric properties of stripes. We present two novel computational methods for analyzing striped patterns in pedestrian data: (i) an edge-cutting algorithm, which detects the dynamic formation of stripes and allows us to measure local properties of individual stripes; and (ii) a pattern-matching technique, based on the Gabor function, which allows us to estimate global properties (orientation and wavelength) of the striped pattern at a time T. We find an invariant property: stripes in the two groups are parallel and perpendicular to the bisector at all crossing angles. In contrast, other properties depend on the crossing angle: stripe spacing (wavelength), stripe size (number of pedestrians per stripe), and crossing time all decrease as the crossing angle increases from 30° to 180°, whereas the number of stripes increases with crossing angle. We also observe that the width of individual stripes is dynamically squeezed as the two groups cross each other. The findings thus support the bisector hypothesis at a wide range of crossing angles, although the theoretical reasons for this invariant remain unclear. The present results provide empirical constraints on theoretical studies and computational models of crossing flows.

On the theory of nonhomogeneous nonequilibrium superconductivity in 2D systems with massless fermions

We analyze static and nonequilibrium superconducting properties of a 2D relativistic-like model system with local electron-electron interaction, Rashba spin-orbit interaction αR in presence of time-dependent in-plane magnetic field H(t). It is shown that similar to the 2D case with ordinary massive quasiparticle dispersion ε(k)∼|k|2 at large fields, such a system demonstrates a nonhomogeneous superconducting stripe phase with the order parameter Δ(r)=Δ(0)cos(2[μBB×r]n/ℏυF) (B is the magnetic induction, υF is the Fermi velocity, n is the normal to the plane, μB is the Bohr magneton, and αR≪υF) where the stripes are oriented along the B direction. In the considered system, the inter-stripe period L and the magnitude of the magnetic field B are related by a universal relation BL=ℏυF/μB≃0.714⋅10−4Tm. Contrary to the case of massive quasiparticles, where the condition αR∼υF can be, in principle, satisfied by increasing αR or by charge doping (Fermi velocity decreasing), in a relativistic-like system, where υF is doping-independent and one-two orders of magnitude larger than typical Fermi velocity in the “standard” 2D systems, the stripe phase can be the ground state at a rather low doping level. We also analyzed the nonequilibrium properties of the system with a focus on the melting of the stripe order (when the magnetic field is quenched to a lower value) and stripe dynamics (when the field is rotated by 90° degrees) and found several notable results. In particular, it was shown that the stripe domains melt according to law R∼1t at initial times, while at longer times they shrink exponentially. In the case of the flipped magnetic field, the stripe orientation gradually turns from x- to y-direction, and the intermediate “crossed-stripe” phase takes place during times of order of picoseconds. Such a crossed phase is built of periodic superconducting bubbles that potentially may have applications in modern ultrafast superconducting technologies.

3D magnetic configuration of ferrimagnetic multilayers with competing interactions visualized by soft X-ray vector tomography

Full control of magnetic properties in exchange coupled systems requires a good understanding of 3D magnetic configuration with lateral and in-depth resolution. Here we show results from a soft X-ray tomographic reconstruction which allow determining, solely from the experimental data, a detailed description of the vector magnetic configuration of a ferrimagnetic Gd12Co88/Nd17Co83/Gd24Co76 trilayer with engineered competing anisotropy, exchange and magnetostatic interactions at different depths. The trilayer displays chevron patterns with a distorted closure structure. Near the top Gd24Co76 layer, local exchange springs with out-of-plane magnetization reversal, quasi-domains with ripple-like patterns and magnetic vortices and antivortices across the thickness are observed. The detailed analysis of the magnetic tomogram shows that the effective strength of the exchange spring at the NdCo/GdCo interface can be finely tuned by GdxCo1-x composition and anisotropy (determined by sample fabrication) and in-plane stripe orientation (adjustable), demonstrating the suitability of 3D magnetic visualization techniques in magnetic engineering research.

Stripe patterns orientation resulting from nonuniform forcings and other competitive effects in the Swift–Hohenberg dynamics

Spatio-temporal pattern formation in complex systems presents rich nonlinear dynamics which leads to the emergence of periodic nonequilibrium structures. One of the most prominent equations for the theoretical and numerical study of the evolution of these textures is the Swift–Hohenberg (SH) equation, which presents a bifurcation parameter (forcing) that controls the dynamics by changing the energy landscape of the system, and has been largely employed in phase-field models. Though a large part of the literature on pattern formation addresses uniformly forced systems, nonuniform forcings are also observed in several natural systems, for instance, in developmental biology and in soft matter applications. In these cases, an orientation effect due to forcing gradients is a new factor playing a role in the development of patterns, particularly in the class of stripe patterns, which we investigate through the nonuniformly forced SH dynamics. The present work addresses amplitude instability of stripe textures induced by forcing gradients, and the competition between the orientation effect of the gradient and other bulk, boundary, and geometric effects taking part in the selection of the emerging patterns. A weakly nonlinear analysis suggests that stripes are stable with respect to small amplitude perturbations when aligned with the gradient, and become unstable to such perturbations when when aligned perpendicularly to the gradient. This analysis is vastly complemented by a numerical work that accounts for other effects, confirming that forcing gradients drive stripe alignment, or even reorient them from preexisting conditions. However, we observe that the orientation effect does not always prevail in the face of competing effects, whose hierarchy is suggested to depend on the magnitude of the forcing gradient. Other than the cubic SH equation (SH3), the quadratic–cubic (SH23) and cubic–quintic (SH35) equations are also studied. In the SH23 case, not only do forcing gradients lead to stripe orientation, but also interfere in the transition from hexagonal patterns to stripes.

Seeing the height at the end of the (wind) tunnel

Without street signs or GPS, animals develop specific and effective strategies for getting where they need to go. To efficiently navigate, honeybees fly lower when facing into the wind and higher when flying with the wind. To understand how some bees determine flight routes despite varying wind conditions, Emily Baird and colleagues at the Australian National University measured whether honeybees’ sight governs their flight paths. They found that bees control their speed and distance from the ground by using different elements of their vision, and that the insects stay on track by making small swerves to the left and right in a wavy pattern.To measure the insects’ flight routes, the team tracked their height and speed relative to the ground by analyzing videos of bees flying through a small wind tunnel, which enabled them to control the speed of the airstream the bees encountered (still air, slow 1 m s−1 or fast 2 m s−1), as well as the direction, so that the bees were flying into the wind or with it. To maximize the visual information available to the bees, the walls of the wind tunnel were lined with a pattern of intersecting perpendicular and parallel stripes made out of red tape on white paper. As the bees flew past the stripes, they swerved left and right, creating a wavy route that allowed the team to better see how they moved in relation to the stripes. Regardless of wind direction, they flew at similar speeds of 0.5 m s−1 but flew lower against the wind and higher when flying with the wind. By measuring what the bees could see based on where they were in the wind tunnel, the researchers determined that the bees maintained a constant view to each side regardless of wind direction, but their view of the ground changed at different heights, which would allow them to achieve different heights in different wind directions.To test whether the bees were relying on the parallel or the perpendicular stripes to determine how high to fly, they used only one stripe orientation, or no stripes at all. When the bees’ visual information was limited by only seeing perpendicular stripes, they maintained similar speeds and swerves to those with full vision but were no longer consistent in their ground height. In contrast, when they could only see stripes parallel to their path, they again flew lower against the wind and higher when flying with the wind. Without seeing perpendicular stripes, though, the bees sped through the wind tunnel at about 1.5 m s−1 without swerving. To simulate low visibility conditions, the researchers tracked bees as they flew through the wind tunnel without any stripes at all – as though flying through dense fog. As with parallel stripes alone, the bees flew straight without swerving. However, without visual cues, their height was inconsistent and they instead modulated their speed to fly slower against the wind and faster with the wind.Honeybees determine how high and how fast to fly according to what they see, and they judge what they see by weaving wavy flight paths in such a way that their own motion helps them to extract clues about their environment. Outside the wind tunnel, bees need to discover new paths based on ever-changing wind and visibility conditions. Instead of street signs, honeybees skilfully find routes using multiple strategies to determine where they are based on what they see.

Correlating Crystallographic Orientation and Ferroic Properties of Twin Domains in Metal Halide Perovskites.

Metal halide perovskite (MHP) solar cells have attracted worldwide research interest. Although it has been well established that grain, grain boundary, and grain facet affect MHPs optoelectronic properties, less is known about subgrain structures. Recently, MHP twin stripes, a subgrain feature, have stimulated extensive discussion due to the potential for both beneficial and detrimental effects of ferroelectricity on optoelectronic properties. Connecting the ferroic behavior of twin stripes in MHPs with crystal orientation will be a vital step to understand the ferroic nature and the effects of twin stripes. In this work, we studied the crystallographic orientation and ferroic properties of CH3NH3PbI3 twin stripes, using electron backscatter diffraction (EBSD) and advanced piezoresponse force microscopy (PFM), respectively. Using EBSD, we discovered that the orientation relationship across the twin walls in CH3NH3PbI3 is a 90° rotation about ⟨1̅1̅0⟩, with the ⟨030⟩ and ⟨111⟩ directions parallel to the direction normal to the surface. By careful inspection of CH3NH3PbI3 PFM results including in-plane and out-of-plane PFM measurements, we demonstrate some nonferroelectric contributions to the PFM responses of this CH3NH3PbI3 sample, suggesting that the PFM signal in this CH3NH3PbI3 sample is affected by nonferroelectric and nonpiezoelectric forces. If there is piezoelectric response, it is below the detection sensitivity of our interferometric displacement sensor PFM (<0.615 pm/V). Overall, this work offers an integrated picture describing the crystallographic orientations and the origin of PFM signal of MHPs twin stripes, which is critical to understanding the ferroicity in MHPs.

Gulf of Aden spreading does not conform to triple-junction formation

AbstractThe Gulf of Aden represents an evolving example of a juvenile ocean system and is considered the most evolved rift arm of the Afar triple junction. We have undertaken analysis of recent coupled satellite and marine potential-field data to understand the first-order crustal architecture along the entire length of the gulf. Our interpretation suggests the Gulf of Aden has three domains with distinct free-air gravity and magnetic characteristics. These domains record a progression from active seafloor spreading in the eastern domain, through isolated and discontinuous spreading segments in the central domain, to active continental rifting in the western domain immediately adjacent to the Afar triple junction. Forward models suggest the presence of transitional crust, which displays linear magnetic stripe–like anomalies that bound oceanic stripes in the central domain and covering the majority of the western domain. Magnetic anomalies differ from magnetic stripes sensu stricto because they are discontinuous and cannot be correlated along the length of the gulf. Detection of northwest-southeast extension in the central domain based on magnetic stripe orientation is inconsistent with the regional northeast-southwest extension. Our observations reflect heterogeneous opening of the Gulf of Aden basins, in which spreading is migrating toward Afar as a series of isolated spreading segments, rather than initiating at the junction as proposed by classical plate-tectonic theory. This mechanism of ocean initiation is inconsistent with transtensional models that involve wholesale tearing of continental crust and contradicts conceptual models that rely on the Afar plume in initiating or driving the extension.

Hybrid Angular Gradient Phase Grating for Measuring the Orbital Angular Momentum of Perfect Optical Vortex Beams

We propose an effective method to measure the orbital angular momentum of a perfect optical vortex (POV) beam with a hybrid angular gradient phase grating (HAG-PG), which is a gradient grating with angular changing distribution. The HAG-PG performs the transformation from the POV to the dark stripes of the diffraction intensity patterns. From the number and the orientation of dark stripes of far-field diffraction patterns formed by the HAG-PG, the modulus of TC and sign of the incident POV beam can be determined. The high scalability of this method for being unrestricted by the Fourier plane and its adaptation for measuring the POV beams with different states are demonstrated by loading the HAG-PG hologram on a spatial light modulator. And the detection sensitivity of the POV beam can be significantly improved. The experimental results agree well with the theoretical simulations.

Electric readout of magnetic stripes in insulators

In superconductors, a topological configuration of the superconducting order parameter called a superconducting vortex carries magnetization. Such a magnetic topological object behaves like a minute particle generating a magnetic flux. Since the flux is localized with a nanometer scale, the vortex provides a nano-scale probe for local magnetic fields. Here we show that information of magnetic stripes in insulators can be read out by using vortices in an adjacent superconductor film as a probe. The orientation and width of magnetic micro stripes are both transcribed into resistance change of the superconductor through the modulation of vortex mobility affected by local magnetization. By changing the direction of external magnetic fields, zero-field resistance changes continuously according to the stripe orientation, and its modulation magnitude reaches up to 100%. The width of the stripes can also be estimated from the oscillatory magnetoresistance. Our results demonstrate a new possibility for non-volatile analog memory devices based on topological objects.

Anomalous behavior of bending deformation induced by a magnetic field in a system of ferromagnetic stripes located on an elastomer

The effect of anomalous bending in a system of magnetically soft ferromagnetic stripes located on a highly elastic plate of elastomer has been studied both experimentally and theoretically. It was found that the magnetic-field dependences for the bending of plates with ferromagnetic stripes have a critical character with a reproduced hysteresis emerging in the repeated cycles of the magnetic field increasing and decreasing. It was found that the magnetically induced bending has a large magnitude, so that the magnetic moments of the stripes at the bending can be directed almost perpendicularly to the magnetic field. In a strong magnetic field, the effect of stripe orientation is observed, which occurs due to the orienting action of Zeeman interaction. It was shown that the hysteresis phenomenon observed at the bending of a plate with stripes is associated with a strong nonlinearity of magnetostatic interaction between the stripes at their magnetization. The hysteresis recurrence is caused by elastic forces arising at the elastomer bending and competing with magnetostatic dipole–dipole interactions between the stripes. The critical points of transitions between the ‘discrete lattice’ state of stripes and the state of laterally touching stripes were determined. A model of the phenomenon concerned was proposed which is in good agreement with experimental data.

What makes motion dazzle markings effective against predation?

AbstractMotion dazzle markings comprise patterns such as stripes and zig-zags that are postulated to protect moving prey by making predators misjudge the prey’s speed or trajectory. Recent experiments have provided conflicting results on their effect on speed perception and attack success. We focus on motion dazzle stripes and investigate the influence of four parameters—stripe orientation, stripe contrast, target size, and target speed—on perceived speed and attack success using a common experimental paradigm involving human “predators” attacking virtual moving targets on a computer touchscreen. We found that high-contrast stripes running parallel or perpendicular to the direction of motion reduce attack success compared to conspicuous uniform targets. Surprisingly, parallel stripes induced underestimation of speed, while perpendicular stripes induced overestimation of speed in relation to uniform black, suggesting that misjudgment of speed per se is sufficient to reduce attack accuracy. Across all the experiments, we found some support for parallel stripes inducing underestimation of target speed but these stripes reduced attack success only when targets were small, moved at an intermediate speed, and had high internal contrast. We suggest that prey features (e.g., size or speed) are an important determinant of capture success and that distortion of speed perception by a color pattern does not necessarily translate to reduced capture success of the prey. Overall, our results support the idea that striped patterns in prey animals can reduce capture in motion but are effective under a limited set of conditions.

Directed transport of liquid droplets on vibrating substrates with asymmetric corrugations and patterned wettability: a dissipative particle dynamics study

ABSTRACTThe development of digital (droplet-based) microfluidic (DMF) devices has received significant attention due to their importance for chemical and biomedical analyses. The precise control and manipulation of liquid droplets on a solid substrate is a major requirement for DMF devices. In this study, we propose a novel strategy to generate continuous droplet motion by combining asymmetric corrugations and patterned wettability on a vibrating substrate. The time periodic oscillations of the substrate with asymmetric triangle corrugations provide the input energy to transport a droplet along patterned stripes. Using dissipative particle dynamic (DPD) simulations, we demonstrate that hydrophobic stripes on a superhydrophobic substrate create a wettability step, which effectively constrains the droplet motion along the stripe. Due to the special design of asymmetric triangle corrugations and orientation of hydrophobic stripes, the proposed strategy enables the transport of multiple droplets with different initial locations towards a single spot and coalescence into a large droplet. We further identify a power-law dependence between the droplet velocity and the period of substrate vibration and show that this function is independent of the droplet size. The proposed droplet transportation strategy can be potentially useful for the efficient manipulation of liquid droplets in DMF devices.

Comments on “The Influence of Equatorial Scintillation on L-Band SAR Image Quality and Phase”

As was indicated in the mentioned paper, the ionospheric stripes, in general, aligned well with the orientation of the projected ambient geomagnetic field vector. However, it is shown in our study that the calculated striping heading is not only dependent upon the orientation of the projected ambient geomagnetic field vector, namely, the geomagnetic heading but also the geomagnetic inclination, the system incident, and squint angle. It also confirms that the changing direction of the visible stripes in the mentioned Phased Array-type L-band Synthetic Aperture Radar (PALSAR) data is mainly due to the variation of the geomagnetic inclination, while the geomagnetic heading is nearly constant along the orbit. Therefore, the denotation and presentation in that research that the projected geomagnetic field vector elongates in the direction of the stripe orientation might not be feasible.

Zebra stripes in the Atacama Desert revisited – Granular fingering as a mechanism for zebra stripe formation?

Although a number of studies have pointed out the remarkable slowness of Earth surface processes in the Atacama Desert, process mechanisms under such extremely limited water availability are poorly understood, and process rates remain unknown. This paper revisits the discussion on the formation of the prominent Atacama-specific hillslope zebra (stone) stripes, previously interpreted to result from palaeo-overland flow (Owen et al., 2013). Compared to this study, our data document different stripe characteristics with regard to stripe form and orientation as well as sorting- and bedding-patterns of stripe-confining surface gravel units. We found a remarkable form-concordance between zebra stripes and deposits from experiments on segregation-induced granular fingering. Hence, we propose a combination of seismic shaking and instantaneous dry granular free surface flows as the key mechanism for zebra stripe formation. Our findings underline the potential significance of seismicity in shaping Atacama landscapes, which bear important analogies to extra-terrestrial surfaces.

Effect of the orientation of laser stripes on the abrasion resistance of biomimetic laser textured surfaces

In order to improve the anti-wear performance of the semi-arc of trailer’s brake shoes, we utilized biomimetic laser texturing to fabricate special striated textures which can play roles in dispatching stress as researched in our previous studies. The orientation of biomimetic stripes was proven to be an important factor to the abrasion resistance of textured surfaces, thus blank samples cut from a brake shoe were modified with 0°, 30°, 45°, 60° and 90° angular distributed laser stripes on their surfaces. All samples undergone 10 hours of dry sliding experiments. The wear result indicated: (i) The biomimetic surface covered with 45° angular distributed stripes has the lowest wear mass loss and the wear resistance of all biomimetic surfaces shown an ascend trend at first and a descend trend at last with the increase of angle between stripe and the wear direction. (ii) When the angle between stripe and the wear direction is 0° (Stripes are parallel to the wear direction), the wear extent was most serious, however, when the angle was changed into 90°, we could deduce that the wear particles could be hindered and accumulated debris and particles would continuously plow softer surface. Only when the angle change into 45° can abrasives be hindered and dispersed in an effective way.