Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of ins...
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Optimal spatial sampling of light rigorously requires that identical photoreceptors be arranged in perfectly regular arrays in two dimensions. Examples of such perfect arrays in nature include the compound eyes of insects and the nearly crystalline photoreceptor patterns of some fish and reptiles. Birds are highly visual animals with five different cone photoreceptor subtypes, yet their photoreceptor patterns are not perfectly regular. By analyzing the chicken cone photoreceptor system consisting of five different cell types using a variety of sensitive microstructural descriptors, we find that the disordered photoreceptor patterns are “hyperuniform” (exhibiting vanishing infinite-wavelength density fluctuations), a property that had heretofore been identified in a unique subset of physical systems, but had never been observed in any living organism. Remarkably, the patterns of both the total population and the individual cell types are simultaneously hyperuniform. We term such patterns “multihyperuniform” because multiple distinct subsets of the overall point pattern are themselves hyperuniform. We have devised a unique multiscale cell packing model in two dimensions that suggests that photoreceptor types interact with both short- and long-ranged repulsive forces and that the resultant competition between the types gives rise to the aforementioned singular spatial features characterizing the system, including multihyperuniformity. These findings suggest that a disordered hyperuniform pattern may represent the most uniform sampling arrangement attainable in the avian system, given intrinsic packing constraints within the photoreceptor epithelium. In addition, they show how fundamental physical constraints can change the course of a biological optimization process. Our results suggest that multihyperuniform disordered structures have implications for the design of materials with novel physical properties and therefore may represent a fruitful area for future research
Information about several papers discussed at the 11th German Conference on Chemoinformatics (GCC) held November 8-10, 2015 sponsored by the Chemistry-Information-Computer (CIC) division of the German Chemical Society...
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Information about several papers discussed at the 11th German Conference on Chemoinformatics (GCC) held November 8-10, 2015 sponsored by the Chemistry-Information-Computer (CIC) division of the German Chemical Society is presented. Topics include accurate description of protein-ligand binding and its functional activity, combination of chemoinformatics and bioinformatics using three dimensional structure of amino acids, and Human Genome Project leading to advancement in drug discovery.
This paper presents a hardware implementation of a robust non-autonomous hyperchaotic-based PRNG driven by a 256-bit LFSR. The original chaotic output is post-processed using a novel technique based on the Fibonacci s...
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This paper presents a hardware implementation of a robust non-autonomous hyperchaotic-based PRNG driven by a 256-bit LFSR. The original chaotic output is post-processed using a novel technique based on the Fibonacci series, bitwise XOR, rotation, and feedback. The proposed post-processing technique preserves the throughput of the system and enhances the randomness in the output which is verified by successfully passing all NIST SP. 800-22 tests. The system is realized on a Xilinx Virtex 4 FPGA achieving throughput up to 13.165 Gbits/s for 16-bit bus-width surpassing previously reported CB-PRNGs.
This paper presents a digital implementation of a 3rd order chaotic system using the Euler approximation. Short-term predictability is studied in relation to system precision, Euler step size and attractor size and op...
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This paper presents a digital implementation of a 3rd order chaotic system using the Euler approximation. Short-term predictability is studied in relation to system precision, Euler step size and attractor size and optimal parameters for maximum performance are derived. Defective bits from the native chaotic output are neglected and the remaining pass the NIST SP. 800-22 tests without post-processing. The resulting optimized pseudorandom number generator has throughput up to 17.60 Gbits/s for a 64-bit design experimentally verified on a Xilinx Virtex 4 FPGA with logic utilization less than 1.85%.
Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensivel...
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Simple physical models based on fluid mechanics have long been used to understand the flow of vehicular traffic on freeways; analytically tractable models of flow on an urban grid, however, have not been as extensively explored. In an ideal world, traffic signals would be timed such that consecutive lights turned green just as vehicles arrived, eliminating the need to stop at each block. Unfortunately, this “green-wave” scenario is generally unworkable due to frustration imposed by competing demands of traffic moving in different directions. Until now this has typically been resolved by numerical simulation and optimization. Here, we develop a theory for the flow in an idealized system consisting of a long two-way road with periodic intersections. We show that optimal signal timing can be understood analytically and that there are counterintuitive asymmetric solutions to this signal coordination problem. We further explore how these theoretical solutions degrade as traffic conditions vary and automotive density increases.
Impact response of contact lenses is measured using the Levitation Mass Method (LMM). In the LMM, a small mass collides with contact lenses and the impact force is measured with high accuracy as the inertial force of ...
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DC faults may cause severe disruptions in continuity of service to vital loads in a shipboard integrated power system, hence detection, isolation, and protection against such faults must be incorporated in both medium...
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The resultant force acting on the moving part of the ceramic aerostatic linear bearing is measured highly accurately as the inertial force of the moving part of the bearing by means of the levitation mass method (LMM)...
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DC faults may cause severe disruptions in continuity of service to vital loads in a shipboard integrated power system, hence detection, isolation, and protection against such faults must be incorporated in both medium...
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DC faults may cause severe disruptions in continuity of service to vital loads in a shipboard integrated power system, hence detection, isolation, and protection against such faults must be incorporated in both medium-voltage DC (MVDC) and low-voltage DC (LVDC) systems. Here we consider the effectiveness of existing z-source breakers and propose several new designs more appropriate for fault detection in MVDC and LVDC systems. In particular, we perform an optimization study that aims to minimize dissipation and weight and we identify the key parameters for use in MVDC and LVDC systems. Preliminary verification and validation studies are also included.
S1 Health literacy and health education in adolescence Catarina Cardoso Tomás S2 The effect of a walking program on the quality of life and well-being of people with schizophrenia Emanuel Oliveira, D. Sousa, M. U...
S1 Health literacy and health education in adolescence Catarina Cardoso Tomás S2 The effect of a walking program on the quality of life and well-being of people with schizophrenia Emanuel Oliveira, D. Sousa, M. Uba-Chupel, G. Furtado, C. Rocha, A. Teixeira, P. Ferreira S3 Diagnosis and innovative treatments - the way to a better medical practice Celeste Alves S4 Simulation-based learning and how it is a high contribution Stefan Gisin S5 Formative research about acceptability, utilization and promotion of a home fortification programme with micronutrient powders (MNP) in the Autonomous Region of Príncipe, São Tomé and Príncipe Elisabete Catarino, Nelma Carvalho, Tiago Coucelo, Luís Bonfim, Carina Silva S6 Safety culture of the patient: a reflexion about the therapeutic approach on the patient with vocal pathology Débora Franco S7 About wine, fortune cookies and patient experience Jesús Alcoba González O1 The psychological impact on the emergency crews after the disaster event on February 20, 2010 Helena G. Jardim, Rita Silva O2 Musculoskeletal disorders in midwives Cristina L. Baixinho, Mª Helena Presado, Mª Fátima Marques, Mário E. Cardoso O3 Negative childhood experiences and fears of compassion: Implications for psychological difficulties in adolescence Marina Cunha, Joana Mendes, Ana Xavier, Ana Galhardo, Margarida Couto O4 Optimal age to give the first dose of measles vaccine in Portugal João G. Frade, Carla Nunes, João R. Mesquita, Maria S. Nascimento, Guilherme Gonçalves O5 Functional assessment of elderly in primary care Conceição Castro, Alice Mártires, Mª João Monteiro, Conceição Rainho O6 Smoking and coronary events in a population of Spanish health-care centre: An observational study Francisco P. Caballero, Fatima M. Monago, Jose T. Guerrero, Rocio M. Monago, Africa P. Trigo, Milagros L. Gutierrez, Gemma M. Milanés, Mercedes G. Reina, Ana G. Villanueva, Ana S. Piñero, Isabel R. Aliseda, Francisco B. Ramirez O7 Prevalence of musculoskeletal injuries in Por
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