X-ray computerized tomography observation of Lycopodium paste incorporating memory of shaking.

In a uniform layer consisting of a mixture of granular material and liquid, it is known that desiccation cracks exhibit various anisotropic patterns that depend on the nature of the shaking that the layer experienced before drying. The existence of this effect implies that information regarding the direction of shaking is retained as a kind of memory in the arrangements of granular particles. In this work we make measurements in paste composed of Lycopodium powder using microfocus x-ray computerized tomography (µCT) in order to investigate the three-dimensional arrangements of particles. We find shaking-induced anisotropic arrangements of neighboring particles and density fluctuations forming interstices mainly in the lower part of the layer. We compare the observed properties of these arrangements with numerical results obtained in the study of a model of non-Brownian particles under shear deformation. In the experimental system, we also observe crack tips in the µCT images and confirm that these cracks grow along interstices in the direction perpendicular to the initial shaking.

[A case of novel WDR45 mutation with beta-propeller protein-associated neurodegeneration (BPAN) presenting asymmetrical extrapyramidal signs].

Beta-propeller protein-associated neurodegeneration (BPAN) is categorized in Neurodegeneration with brain iron accumulation. The clinical feature of BPAN is global developmental delay in early childhood, followed rapid progression of cognitive disfunction and parkinsonism in adulthood. This case was pointed out intellectual disability at the age of 9, followed left dominant progressive parkinsonism from the age of 31. Brain MRI showed the T1-weighted signal hyperintensity of the substantia nigra with a central band of hypointensity and the T2 star weighted image hypointensity of substantia nigra and globus pallidus presenting dominant at right side. DAT SPECT also showed specific binding ratio decreased dominant in right side. She was diagnosed BPAN based on her genetic test revealing a novel mutation (c.411dupT) in WDR45. No studies reported detailed parkinsonism like laterality in BPAN. This case indicates the left dominant parkinsonism was caused by right dominant iron deposition to substantia nigra and globus pallidus in view of MRI findings and DAT SPECT.

Memory effect and anisotropy of particle arrangements in granular paste.

It is known that pastes of fine powder, for example those of clay, retain memory of shaking applied early in a drying process. This memory results in the appearance of anisotropic patterns of desiccation cracks after drying. In this work, we find a similar behavior in pastes consisting of large granular particles, specifically cornstarch and Lycopodium spores. Because of the large particle size, we were able to observe particle arrangements in Lycopodium paste with micro-focus X-ray computerized tomography ( µ CT). We prepared pastes consisting of Lycopodium particles and water. Agar was added to the paste in order to allow for solidification during a drying process. In these samples, we found statistical anisotropy induced by shaking applied early in the drying process. This anisotropy possesses a feature that was predicted on the basis of results obtained in previous experimental and theoretical studies.

Coordinated Behaviour in Pigeon Flocks.

We analysed pigeon flock flights using GPS trajectory data to reveal the most important kinematic aspects of flocking behaviour. We quantitatively investigated the internal motion of the flock based on pairwise statistics and found the following general relationships in all datasets: i) the temporal order of decisions characterised by the delay between directional changes is strictly related to the spatial order characterised by the longitudinal relative position within the flock; ii) during circling motion, pigeons use a mixture of two idealised and fundamentally different turning strategies, namely, parallel-path and equal-radius type turning. While pigeons tend to maintain their relative position within the flock on average, as in the parallel-path approximation, those who turn later also get behind as in the equal-radius case. Equal-radius type turning also tends to be expressed more during smaller radius turns.

Spatio-temporal structure of hooded gull flocks.

We analyzed the spatio-temporal structure of hooded gull flocks with a portable stereo camera system. The 3-dimensional positions of individuals were reconstructed from pairs of videos. The motions of each individual were analyzed, and both gliding and flapping motions were quantified based on the velocity time series. We analyzed the distributions of the nearest neighbor's position in terms of coordinates based on each individual's motion. The obtained results were consistent with the aerodynamic interaction between individuals. We characterized the leader-follower relationship between individuals by a delay time to mimic the direction of a motion. A relation between the delay time and a relative position was analyzed quantitatively, which suggested the basic properties of the formation flight that maintains order in the flock.

Scytale decodes chaos: a method for estimating unstable symmetric solutions.

A method for estimating a period of unstable periodic solutions is suggested in continuous dissipative chaotic dynamical systems. The measurement of a minimum distance between a reference state and an image of transformation of it exhibits a characteristic structure of the system, and the local minima of the structure give candidates of period and state of corresponding symmetric solutions. Appropriate periods and initial states for the Newton method are chosen efficiently by setting a threshold to the range of the minimum distance and the period.

Numerical study of drying process and columnar fracture process in granule-water mixtures.

The formation of three-dimensional prismatic cracks in the drying process of starch-water mixtures is investigated numerically. We assume that the mixture is an elastic porous medium which possesses a stress field and a water content field. The evolution of both fields is represented by a spring network and a phenomenological model with the water potential, respectively. We find that the water content distribution has a propagating front which is not explained by a simple diffusion process. The prismatic structure of cracks driven by the water content field is observed. The depth dependence and the coarsening process of the columnar structure are also studied. The particle diameter dependence of the scale of the columns and the effect of the crack networks on the dynamics of the water content field are also discussed.

Chaotically oscillating interfaces in a parametrically forced system.

Structures and motions of a single interface exhibiting chaotic behavior are studied in the one-dimensional parametrically forced complex Ginzburg-Landau equation. There exist two kinds of chaotic interfaces whose differences are characterized by their chiral symmetry and the diffusivity of their motion. The transition between these behaviors is also investigated from the viewpoint of singularities of several dynamical variables, such as the diffusion constant, the resident time to each state, and the maximum trapping time to the unstable solution.

Directional crack propagation of granular water systems.

Pattern dynamics of directional crack propagation phenomena observed in drying process of starch-water mixture is investigated. To visualize the three-dimensional structure of the drying-fracture process two kinds of experiments are performed, i.e., resin solidification planing method and real-time measurement of water content distribution with MR instruments. A cross section with polygonal structure is visualized in both experiments. The depth dependency of cell size is measured. The phenomenological model for water transportation is also discussed.

Haploinsufficiency of NSD1 causes Sotos syndrome.

We isolated NSD1 from the 5q35 breakpoint in an individual with Sotos syndrome harboring a chromosomal translocation. We identified 1 nonsense, 3 frameshift and 20 submicroscopic deletion mutations of NSD1 among 42 individuals with sporadic cases of Sotos syndrome. The results indicate that haploinsufficiency of NSD1 is the major cause of Sotos syndrome.