Wavelet Based Fractal Analysis of Airborne Pollen

The most abundant biological particles in the atmosphere are pollen grains and spores. Self protection of pollen allergy is possible through the information of future pollen contents in the air. In spite of the importance of airborne pol len concentration forecasting, it has not been possible to predict the pollen concentrations with great accuracy, and about 25% of the daily pollen forecasts have resulted in failures. Previous analysis of the dynamic characteristics of atmospheric pollen time series indicate that the system can be described by a low dimensional chaotic map. We apply the wavelet transform to study the multifractal characteristics of an a irborne pollen time series. We find the persistence behaviour associated to low pollen concentration values and to the most rare events of highest pollen co ncentration values. The information and the correlation dimensions correspond to a chaotic system showing loss of information with time evolution.Comment: 11 pages, 7 figure

Complementary DNA sequences of two 14.5 kDa subunits of NADH:ubiquinone oxidoreductase from bovine heart mitochondria Completion of the primary structure of the complex?

AbstractThe amino acid sequences of two nuclear-encoded subunits of complex I from bovine heart mitochondria have been determined. Both proteins have an apparent molecular weight of 14.5 kDa and their N-α-amino groups are acetylated. They are known as subunits B14.5a and B14.5b. Neither protein is evidently related to any known protein and their functions are obscure. A total of 34 nuclear-encoded subunits of bovine complex 1 have now been sequenced and it is thought that the primary structure of the complex is now complete, although with such a complicated structure it is difficult to be certain that there are no other subunits remaining to be sequenced. Seven additional hydrophobic subunits of the enzyme are encoded in mitochondrial DNA, and therefore bovine heart complex I is an assembly of about 41 different proteins. If it is assumed that there is one copy of each protein in the assembly, these polypeptides contain 7,955 amino acids in their sequences, more than are found in the Escherichia coli ribosome, which contains 7,336 amino acids in its 32 polypeptides

Sphere rolling on the surface of a cone

We analyse the motion of a sphere that rolls without slipping on a conical surface having its axis in the direction of the constant gravitational field of the Earth. This nonholonomic system admits a solution in terms of quadratures. We exhibit that the only circular of the system orbit is stable and furthermore show that all its solutions can be found using an analogy with central force problems. We also discuss the case of motion with no gravitational field, that is, of motion on a freely falling cone.Comment: 12 pages, 2 figures, to be published in Eur J Phy

Luminescence study of thermal treated and laser irradiated Bi_12GeO_20 and Bi_12SiO_20 crystals

Changes on the defect structure of Bi12GeO20 (BGO) and Bi12SiO20 (BSO) crystals induced by thermal treatments and laser irradiation have been studied by means of cathodoluminescence in the scanning electron microscope. The results have been compared to those previously reported for untreated and electron irradiated samples and recombination mechanisms responsible for some of the observed luminescence bands are discussed. Annealing of EGO samples causes the appearance of a new luminescence band at about 390 nm. The centers responsible for this band decorate the deformation slip bands in quenched EGO as observed in the cathodoluminescence images. The emission observed in BSO in the same spectral range is quenched during the annealing treatment. The annealing induced reduction of Bi ions to metallic Bi appears to be related to the quenching of a band at 640 nm observed in untreated samples

Assessing the Robustness of Cluster Solutions Obtained From Sparse Count Matrices

Psychological researchers often seek to obtain cluster solutions from sparse count matrices (e.g., social networks; counts of symptoms that are in common for 2 given individuals; structural brain imaging). Increasingly, community detection methods are being used to subset the data in a data-driven manner. While many of these approaches perform well in simulation studies and thus offer some improvement upon traditional clustering approaches, there is no readily available approach for evaluating the robustness of these solutions in empirical data. Researchers have no way of knowing if their results are due to noise. We describe here 2 approaches novel to the field of psychology that enable evaluation of cluster solution robustness. This tutorial also explains the use of an associated R package, perturbR, which provides researchers with the ability to use the methods described herein. In the first approach, the cluster assignment from the original matrix is compared against cluster assignments obtained by randomly perturbing the edges in the matrix. Stable cluster solutions should not demonstrate large changes in the presence of small perturbations. For the second approach, Monte Carlo simulations of random matrices that have the same properties as the original matrix are generated. The distribution of quality scores ("modularity") obtained from the cluster solutions from these matrices are then compared with the score obtained from the original matrix results. From this, one can assess if the results are better than what would be expected by chance. perturbR automates these 2 methods, providing an easy-to-use resource for psychological researchers. We demonstrate the utility of this package using benchmark simulated data generated from a previous study and then apply the methods to publicly available empirical data obtained from social networks and structural neuroimaging

Synergy between pyroelectric and photovoltaic effects for optoelectronic nanoparticle manipulation

© 2019 Optical Society of America. Users may use, reuse, and build upon the article, or use the article for text or data mining, so long as such uses are for non-commercial purposes and appropriate attribution is maintained. All other rights are reserved.The combined action of the pyroelectric (PY) and photovoltaic (PV) effects, exhibited by z-cut LiNbO3:Fe substrates, has been investigated for particle trapping and patterning applications. The novel hybrid procedure provides new possibilities and versatility to optoelectronic manipulation on LiNbO3 substrates. It has allowed obtaining periodic and arbitrary 2D patterns whose particle density distribution is correlated with the light intensity profile but can be tuned through ΔT according to the relative strength of the PV and PY effects. A relevant result is that the PY and PV contributions compete for a ΔT range of 1-20 °C, very accessible for experiments. Moreover, the synergy of the PY and PV has provided two additional remarkable applications: i) A method to measure the PV field, key magnitude for photovoltaic optoelectronic tweezers. Using this method, the minimum field needed to obtain a particle pattern has been determined, resulting relatively high, E~60 kV/cm, and so, requiring highly doped crystals when only using the PV effect. ii) An strategy combining the PY and PV to get particle patterning in samples inactive for PV trapping when the PV field value is under that thresholdMinisterio de Ciencia, Innovación y Universidades of Spain (MAT2014-57704-C3, MAT2017-83951-R); Universidad Politécnica de Madrid (RR01/2016

Traffic of Molecular Motors

Molecular motors perform active movements along cytoskeletal filaments and drive the traffic of organelles and other cargo particles in cells. In contrast to the macroscopic traffic of cars, however, the traffic of molecular motors is characterized by a finite walking distance (or run length) after which a motor unbinds from the filament along which it moves. Unbound motors perform Brownian motion in the surrounding aqueous solution until they rebind to a filament. We use variants of driven lattice gas models to describe the interplay of their active movements, the unbound diffusion, and the binding/unbinding dynamics. If the motor concentration is large, motor-motor interactions become important and lead to a variety of cooperative traffic phenomena such as traffic jams on the filaments, boundary-induced phase transitions, and spontaneous symmetry breaking in systems with two species of motors. If the filament is surrounded by a large reservoir of motors, the jam length, i.e., the extension of the traffic jams is of the order of the walking distance. Much longer jams can be found in confined geometries such as tube-like compartments.Comment: 10 pages, latex, uses Springer styles (included), to appear in the Proceedings of "Traffic and Granular Flow 2005

Disorder Induced Diffusive Transport In Ratchets

The effects of quenched disorder on the overdamped motion of a driven particle on a periodic, asymmetric potential is studied. While for the unperturbed potential the transport is due to a regular drift, the quenched disorder induces a significant additional chaotic ``diffusive'' motion. The spatio-temporal evolution of the statistical ensemble is well described by a Gaussian distribution, implying a chaotic transport in the presence of quenched disorder.Comment: 10 pages, 4 EPS figures; submitted to Phys. Rev. Letter