Evolving small spiking neural networks to work as state machines for temporal pattern recognition

Peer reviewe

The size of selected human skull foramina in relation to skull capacity

An anatomical study was undertaken in order to investigate whether the sizes of selected human skull foramina with significant venous compartments correlated significantly with skull capacity. A total of 100 macerated human skulls were examined to determine the diameter of the foramina and the skull capacity. Measurements of the surface area of the foramina were made using a computerised digital analysis system. Only the size of the hypoglossal canal and jugular foramen were found to correlate significantly with the capacity of the skull. This correlation, together with the considerable size of the hypoglossal canal, indicated its important role in the venous drainage of the brain. There was considerable centralisation of venous outflow from the brain, with 60% of the area of all venous foramina of the skull occupied by jugular foramina. Asymmetry between the right and left jugular foramina was identified, with an average ratio of 1.6 (ranging between 1 and 3.47). In the case of right-sided domination the correlation between the skull capacity and the size of both jugular foramina was negative (the larger the skull cavity, the less the asymmetry), while in the case of left-sided domination the correlation was positive. Perhaps the left-sided domination is less advantageous for the haemodynamics of blood outflow, as the left brachiocephalic vein is longer and is often compressed by the sternum and aortic arch

Topography and morphometry of the subarcuate canal

The current study shows in a close-up view anatomical relationship between the subarcuate canal and the osseous labyrinth. For this purpose we used micro-computed tomography which allowed performing three-dimensional reconstruction of the subarcuate canal and gave adequate data for estimation its diameter across its course. The diameter of the middle part (the most uniform) of the subarcuate canal varied from 0.28 mm to 0.46 mm. Hence, we calculated the centre of mass for each cross-section of the separated subarcuate canal. This procedure helped us to visualise trajectory of the subarcuate canal and its spatial orientation within the petrous bone. From our data we concluded that subarcuate canals revealed not well defined trajectories and their spatial orientation varied across the studied temporal bones

Low energy states with different symmetries in the t-J model with two holes on a 32-site lattice

We study the low energy states of the t-J model with two holes on a 32-site lattice with periodic boundary conditions. In contrary to common belief, we find that the state with d_{x^2-y^2} symmetry is not always the ground state in the realistic parameter range 0.2\le J/t\le 0.4. There exist low-lying finite-momentum p-states whose energies are lower than the d_{x^2-y^2} state when J/t is small enough. We compare various properties of these low energy states at J/t=0.3 where they are almost degenerate, and find that those properties associated with the holes (such as the hole-hole correlation and the electron momentum distribution function) are very different between the d_{x^2-y^2} and p states, while their spin properties are very similar. Finally, we demonstrate that by adding ``realistic'' terms to the t-J model Hamiltonian, we can easily destroy the d_{x^2-y^2} ground state. This casts doubt on the robustness of the d_{x^2-y^2} state as the ground state in a microscopic model for the high temperature superconductors

Three dimensional visualisation and morphometry of bone samples studied in microcomputed tomography (micro-CT)

This article highlights the utility of micro-computed tomography (micro-CT) for characterisingmicroscale bone morphology. For this purpose we tested selected samplesof the human bones (Wormian bone, rib, lumbar vertebra) to reconstruct externaland internal morphological features. Selected bony samples were investigatedusing a micro-CT scanner (Skyscan 1172, N.V., Aartselaar, Belgium). The imageresolution of scans varied from 5 to 27 μm/pixel depending on the bone sample.We used CTvox software (by Skyscan) to perform volume rendering of the samples.Further, 3-dimensional geometrical models were reconstructed using theCTvol application. Such models enabled graphical distinction between osseouscomponents of various morphology and were used to visualise the Haversian canalsystem inside the compact bone of the rib. Applying a modified transfer functionfor volume rendering we presented the overall morphology of the Wormian boneand small vascular channels penetrating its interior. As an example of quantitativeanalysis based on micro-CT scans we compared the trabecular structure of thelumbar vertebrae with CTAn software. Significant differences in percent bonevolume (BV/TV) were determined. Micro-CT was found to be a very accurate andhelpful method to study small anatomical structures of the bones in micro scale

Automatic method for the dermatological diagnosis of selected hand skin features in hyperspectral imaging

Introduction: Hyperspectral imaging has been used in dermatology for many years. The enrichment of hyperspectral imaging with image analysis broadens considerably the possibility of reproducible, quantitative evaluation of, for example, melanin and haemoglobin at any location in the patient's skin. The dedicated image analysis method proposed by the authors enables to automatically perform this type of measurement. Material and method: As part of the study, an algorithm for the analysis of hyperspectral images of healthy human skin acquired with the use of the Specim camera was proposed. Images were collected from the dorsal side of the hand. The frequency λ of the data obtained ranged from 397 to 1030 nm. A total of 4'000 2D images were obtained for 5 hyperspectral images. The method proposed in the paper uses dedicated image analysis based on human anthropometric data, mathematical morphology, median filtration, normalization and others. The algorithm was implemented in Matlab and C programs and is used in practice. Results: The algorithm of image analysis and processing proposed by the authors enables segmentation of any region of the hand (fingers, wrist) in a reproducible manner. In addition, the method allows to quantify the frequency content in different regions of interest which are determined automatically. Owing to this, it is possible to perform analyses for melanin in the frequency range λE∈(450,600) nm and for haemoglobin in the range λH∈(397,500) nm extending into the ultraviolet for the type of camera used. In these ranges, there are 189 images for melanin and 126 images for haemoglobin. For six areas of the left and right sides of the little finger (digitus minimus manus), the mean values of melanin and haemoglobin content were 17% and 15% respectively compared to the pattern. Conclusions: The obtained results confirmed the usefulness of the proposed new method of image analysis and processing in dermatology of the hand as it enables reproducible, quantitative assessment of any fragment of this body part. Each image in a sequence was analysed in this way in no more than 100 ms using Intel Core i5 CPU M460 @2.5 GHz 4 GB RAM

Relation between flux formation and pairing in doped antiferromagnets

We demonstrate that patterns formed by the current-current correlation function are landmarks which indicate that spin bipolarons form in doped antiferromagnets. Holes which constitute a spin bipolaron reside at opposite ends of a line (string) formed by the defects in the antiferromagnetic spin background. The string is relatively highly mobile, because the motion of a hole at its end does not raise extensively the number of defects, provided that the hole at the other end of the line follows along the same track. Appropriate coherent combinations of string states realize some irreducible representations of the point group C_4v. Creep of strings favors d- and p-wave states. Some more subtle processes decide the symmetry of pairing. The pattern of the current correlation function, that defines the structure of flux, emerges from motion of holes at string ends and coherence factors with which string states appear in the wave function of the bound state. Condensation of bipolarons and phase coherence between them puts to infinity the correlation length of the current correlation function and establishes the flux in the system.Comment: 5 pages, 6 figure

New results for the t-J model in ladders: Changes in the spin liquid state with applied magnetic field. Implications for the cuprates

Exact Diagonalization calculations are presented for the t-J model in the presence of a uniform magnetic field. Results for 2xL ladders (L=8,10,12) and 4x4 square clusters with 1 and 2 holes indicate that the diamagnetic response to a perpendicular magnetic field tends to induce a spin liquid state in the spin background. The zero-field spin liquid state of a two-leg ladder is reinforced by the magnetic field: a considerable increase of rung antiferromagnetic correlations is observed for J/t up to 0.6, for 1 and 2 holes. Pair-breaking is also clearly observed in the ladders and seems to be associated in part with changes promoted by the field in the spin correlations around the zero-field pair. In the 4x4 cluster, the numerical results seem to indicate that the field-induced spin liquid state competes with the zero-field antiferromagnetic short-range-order, the spin liquid state being favored by higher doping and smaller values of J/t. It is interesting to note that the field-effect can also be observed in a 2x2 plaquette with 1 and 2 holes. This opens up the possibility of gaining a qualitative understanding of the effect.Comment: 16 pages, 7 figures, latex New results adde

Large cell anaplastic lypmhoma versus Hodgkin's disease – difficulties in the diagnosis

AbstractDuring the last 5 years in the Polish Children's Leukemia/Lymphoma Study Group (7 centers) 241 children with Hodgkin's Disease and 14 children with Large Cell Anaplastic Lymphoma were treated.In 5 of them we had problems with differential diagnosis.Immunohistochemical tests:–CD30 positive, CD15 positive, LCA negative allowed us to change the diagnosis from Large Cell Anaplastic Lymphoma to Hodgkin's Disease (one child) and–CD30 positive, CD15 negative from Hodgkin's Disease to Large Cell Anaplastic Lymphoma (four children).All children achieved remission after changing the protocol of chemotherapy